Corticosteroid levels and male mortality in Antechinus stuartii

1977 ◽  
pp. 209-220 ◽  
Author(s):  
Anthony K. Lee ◽  
Adrian J. Bradley ◽  
Richard W. Braithwaite
Keyword(s):  
Male Mortality ◽  
Antechinus Stuartii

Reproductive parameters of surviving 'die-off' male Antechinus flavipes and Antechinus stuartii (Dasyuridae : Marsupialia) in their second year of life

2009 ◽  
Vol 31 (1) ◽  
pp. 17 ◽  
Author(s):  
B. M. McAllan
Keyword(s):  
Male Mortality ◽  
Mating Period ◽  
Second Year Of Life ◽  
Sexual Characteristics ◽  
In Captivity ◽  
In The Wild ◽  
Antechinus Stuartii ◽  
Second Year ◽  
And Function ◽  
First Year Of Life

Males of the genus Antechinus (Dasyuromorphia) undergo dramatic behavioural, physical and physiological change that results in complete male mortality after the mating period. Occasionally, males in the wild survive longer than this immediate post-mating period, and post ‘die-off’ survivorship for a second year has also been documented in captivity. The present study sought to quantify changes in the physiology and behaviour of male A. flavipes and A. stuartii that survive through a second year of life. Males from both species never demonstrated spermatorrhoea in their second year, although secondary sexual characteristics and sexual behaviour were recovered in their second year. Thus, the seminiferous tubular collapse seen before the mating period in their first year of life is irreversible and complete, although the cycling of other sexual characteristics suggests that the hypothalamic-pituitary-gonadal pathways and function of the interstitial cells of the testes are retrievable.

The parasites of Antechinus stuartii Macleay from Powelltown, Victoria, with observations on seasonal and sex-related variations in numbers of Helminths

1976 ◽  
Vol 24 (2) ◽  
pp. 265 ◽  
Author(s):  
I Beveridge ◽  
IK Barker
Keyword(s):  
Detailed Examination ◽  
Male Mortality ◽  
Seasonal Mortality ◽  
Antechinus Stuartii ◽  
Population Sizes ◽  
Made In

A detailed examination of helminth and arthropod parasites was made in association with a study of male mortality in A. stuartii from Powelltown. The prevalence and population sizes of Woolleya spp., Capillaria rickardi and Peramelistrongylus skedatos rose sharply in the period June-August, male A. stuartii being significantly more heavily parasitized than females. It was considered unlikely that the parasites encountered are directly involved in the seasonal mortality of male A. stuartii.

Observations on Spontaneous Stress-Related Mortality Among Males of the Dasyurid Marsupial Antechinus Stuartii Macleay.

1978 ◽  
Vol 26 (3) ◽  
pp. 435 ◽  
Author(s):  
IK Barker ◽  
I Beveridge ◽  
AJ Bradley ◽  
AK Lee
Keyword(s):  
Gastrointestinal Haemorrhage ◽  
Hepatic Necrosis ◽  
Male Mortality ◽  
Duodenal Ulcers ◽  
Concomitant Reduction ◽  
Antechinus Stuartii ◽  
Response To Stress ◽  
Latent Disease ◽  
High Level ◽  
Related Mortality

Splenic follicle sizes in male A. stuartii killed during the period of male mortality in 1973 were smaller than those of females killed at the same time. In 1974, all 17 males and two of four females held in the laboratory died during the period of male mortality in the field. Significant findings in some moribund animals included moderate anaemia, associated with heavy parasitaemias by Babesia sp. and elevated plasma corticosteroid levels. At autopsy, a high proportion of animals had haemoglobinuria, focal hepatic necrosis, and gastrointestinal haemorrhage due to gastric and duodenal ulcers. Males dying spontaneously had severely involuted splenic follicles. Listeria monocytogenes was recovered from four livers with focal necrosis but not from six livers with no necrotic foci. Splenic follicles were smaller in one group of males treated experimentally with a high level of exogenous corticosteroid. Deaths were related mainly to gastrointestinal haemorrhage, listeriosis and possibly babesiosis, considered to be associated with an adrenocortical response to stress, and concomitant reduction in resistance to infec- tion or latent disease. The probability that this syndrome is involved in mortality in the field is discussed.

Changes in the Haematology of Antechinus Stuartii (Marsupialia), and Their Association With Male Mortality.

1976 ◽  
Vol 24 (3) ◽  
pp. 299 ◽  
Author(s):  
PD Cheal ◽  
AK Lee ◽  
JL Barnett
Keyword(s):  
Oxygen Consumption ◽  
Stress Response ◽  
Seasonal Changes ◽  
Haemoglobin Concentration ◽  
Gastrointestinal Haemorrhage ◽  
Blood Parameters ◽  
Severe Stress ◽  
Aerobic Scope ◽  
Male Mortality ◽  
Antechinus Stuartii

Seasonal changes in the blood parameters of A. stuartii show that most males and a few females are anaemic immediately preceding the post-mating mortality of males. Gastrointestinal haemorrhage and intravascular haemolysis, possibly resulting from infections of Babesia sp., appear probable causes of the anaemias. The marked lymphopenias and neutrophilias observed in males, but not females, are consistent with other evidence of a severe stress response in males at this time. The reduction in haemoglobin concentration and haematocrit detected in most anaemic animals was correlated with an increase in the resting oxygen consumption and a reduction in aerobic scope. These changes coincide with a time of considerable energy expenditure by males and may contribute to their demise.

The role of production and non-production factors in the formation of male mortality (on the example of two Arctic single-industry towns)

2020 ◽  
Vol 60 (11) ◽  
pp. 738-741
Author(s):  
Maria S. Bryleva
Keyword(s):  
Negative Impact ◽  
Well Being ◽  
Malignant Neoplasms ◽  
Male Mortality ◽  
Occupational Factors ◽  
Copper Nickel ◽  
Production Factors ◽  
Single Industry ◽  
Working Age ◽  
Quality Of Medical Care

Introduction. One of the priority socio-economic and medical-demographic problems in Russia is the high mortality. The study aim is to identify the most significant factors that determine the mortality on the example of two single-industry towns. Materials and methods. Mortality in two single-industry towns specializing in copper-nickel production, differenced in climate, environmental, and socio-economic indicators, was studied using age-standardized indicators averaged over 8 years (2010-2017). Results. In Monchegorsk, compared to Russia, with similar non-production characteristics, working-age mortality from cardiovascular diseases (CVD) was higher by 49.0%, from malignant neoplasms (MN) by 34.7%, from diseases of the digestive system by 35.5%, which confirms the negative impact of occupational factors on the mortality of the population of a single-industry city. In Norilsk city, with the worst characteristics of the environment and climate, compared to Monchegorsk, mortality from CVD was lower in working age by 40.6%, in post-working age by 41.4%; from MN - in working age lower by 37.2% that shows the compensating influence of socio-economic factors on mortality. Conclusion. Risk factors for increased mortality rates in single-industry towns with copper-nickel enterprises are the influence of harmful occupational factors, as well as environmental pollution. Along with primary prevention, an effective mechanism for reducing mortality is to improve socio-economic well-being, and the quality of medical care.

scholarly journals Monocyte subsets predict mortality after cardiac arrest

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K.A Krychtiuk ◽  
M Lenz ◽  
B Richter ◽  
K Huber ◽  
J Wojta ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Spontaneous Circulation ◽  
Strong Increase ◽  
Funding Source ◽  
Monocyte Subset ◽  
Male Mortality ◽  
National Budget ◽  
Classical Monocytes ◽  
Intermediate Monocytes ◽  
Subset Distribution

Abstract Background After successful cardiopulmonary resuscitation with return of spontaneous circulation (ROSC), many patients show signs of an overactive immune activation. Monocytes are a heterogenous cell population that can be distinguished into three subsets. Purpose The aim of this prospective, observational study was to analyze whether monocyte subset distribution is associated with mortality at 6 months in patients after cardiac arrest. Methods We included 53 patients admitted to our medical ICU after cardiac arrest. Blood was taken on admission and monocyte subset distribution was analyzed by flow cytometry and distinguished into classical monocytes (CM; CD14++CD16-), intermediate monocytes (IM; CD14++CD16+CCR2+) and non-classical monocytes (NCM; CD14+CD16++CCR2-). Results Median age was 64.5 (IQR 49.8–74.3) years and 75.5% of patients were male. Mortality at 6 months was 50.9% and survival with good neurological outcome was 37.7%. Of interest, monocyte subset distribution upon admission to the ICU did not differ according to survival. However, patients that died within 6 months showed a strong increase in the pro-inflammatory subset of intermediate monocytes (8.3% (3.8–14.6)% vs. 4.1% (1.5–8.2)%; p=0.025), and a decrease of classical monocytes (87.5% (79.9–89.0)% vs. 90.8% (85.9–92.7)%; p=0.036) 72 hours after admission. In addition, intermediate monocytes were predictive of outcome independent of initial rhythm and time to ROSC and correlated with the CPC-score at 6 months (R=0.32; p=0.043). Discussion Monocyte subset distribution is associated with outcome in patients surviving a cardiac arrest. This suggests that activation of the innate immune system may play a significant role in patient outcome after cardiac arrest. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): FWF - Fonds zur Förderung der wissenschaftlichen Forschung

Effects of logging and fire on small mammals in Mumbulla State Forest, near Bega, New South Wales

1987 ◽  
Vol 14 (2) ◽  
pp. 163 ◽  
Author(s):  
D. Lunney ◽  
B. Cullis ◽  
P. Eby
Keyword(s):  
Small Mammals ◽  
New South ◽  
New South Wales ◽  
Canopy Cover ◽  
Ground Cover ◽  
First Year ◽  
Severe Effect ◽  
South Wales ◽  
Antechinus Stuartii ◽  
Rattus Fuscipes

This study of the effects of logging on small mammals in Mumbulla State Forest on the south coast of New South Wales included the effects of a fire in November 1980 and a drought throughout the study period from June 1980 to June 1983. Rattus fuscipes was sensitive to change: logging had a significant impact on its numbers, response to ground cover, and recapture rate; fire had a more severe effect, and drought retarded the post-fire recovery of the population. The three species of dasyurid marsupials differed markedly in their response to ground cover, canopy cover, logging and fire. Antechinus stuartii was distributed evenly through all habitats and was not affected by logging, but fire had an immediate and adverse effect which was sustained by the intense drought. A. swainsonii markedly preferred the regenerating forest, and was not seen again after the fire, the failure of the population being attributed to its dependence on dense ground cover. Sminthopsis leucopus was found in low numbers, appeared to prefer forest with sparse ground cover, and showed no immediate response to logging or fire; its disappearance by the third year post-fire suggests that regenerating forest is inimical to the survival of this species. Mus musculus showed no response to logging. In the first year following the fire its numbers were still very low, but in the next year there was a short-lived plague which coincided with the only respite in the 3-year drought and, importantly, occurred in the intensely burnt parts of the forest. The options for managing this forest for the conservation of small mammals include minimising fire, retaining unlogged forest, extending the time over which alternate coupes are logged and minimising disturbance from heavy machinery.

Effects of phytoseiid predators on the sex ratio of the spider mite Panonychus ulmi

1991 ◽  
Vol 69 (1) ◽  
pp. 208-212 ◽  
Author(s):  
Dan L. Johnson ◽  
Heather C. Proctor
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Spider Mite ◽  
Total Population ◽  
Panonychus Ulmi ◽  
Encounter Rate ◽  
Male Mortality ◽  
Adult Sex Ratio ◽  
Biased Sex Ratio ◽  
Male Activity

The effect of predator presence on the adult sex ratio of a spider mite (Panonychus ulmi) was examined in a field experiment. Phytoseiid predators (chiefly Typhlodromus occidentalis) were removed from 32 trees harboring P. ulmi populations, and allowed to remain at natural levels on 32 other trees. Both total population density and proportion of males in the prey population were significantly higher in predator-free trees. Mechanisms that could explain the increase in the proportion of males are examined. The most probable is that greater male activity results in a higher encounter rate between predator and prey, and that subsequent higher male mortality when predators are present exaggerates the female-biased sex ratio. The theoretical effects of sex-biased predation on diplo-diploid and haplo-diploid organisms are discussed.

Powerline Easements: Do They Promote Edge Effects in Eucalypt Forest for Small Mammals?

1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan
Keyword(s):  
Small Mammals ◽  
Edge Effects ◽  
Native Species ◽  
Vegetative Cover ◽  
Mammal Species ◽  
Terrestrial Mammals ◽  
Eucalypt Forest ◽  
Hair Sampling ◽  
South Wales ◽  
Antechinus Stuartii

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.

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