13 research outputs found
Mammal responses to global changes in human activity vary by trophic group and landscape
Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.Peer reviewe
Intra-abdominal fat is a major determinant of the National Cholesterol Education Program Adult Treatment Panel III Criteria for the Metabolic Syndrome
The underlying pathophysiology of the metabolic
syndrome is the subject of debate, with both insulin
resistance and obesity considered as important
factors. We evaluated the differential effects of insulin
resistance and central body fat distribution in
determining the metabolic syndrome as defined by
the National Cholesterol Education Program (NCEP)
Adult Treatment Panel III. In addition, we determined
which NCEP criteria were associated with insulin
resistance and central adiposity. The subjects,
218 healthy men (n = 89) and women (n = 129)
with a broad range of age (26–75 years) and BMI
(18.4–46.8 kg/m2), underwent quantification of the
insulin sensitivity index (Si) and intra-abdominal fat
(IAF) and subcutaneous fat (SCF) areas. The metabolic
syndrome was present in 34 (15.6%) of subjects
who had a lower Si [median: 3.13 vs. 6.09 ×
× 10–5 min–1/(pmol/l)] and higher IAF (166.3 vs. 79.1 cm2)
and SCF (285.1 vs. 179.8 cm2) areas compared with
subjects without the syndrome (P < 0.001). Multivariate
models including Si, IAF, and SCF demonstrated
that each parameter was associated with the
syndrome. However, IAF was independently associated
with all five of the metabolic syndrome criteria.
In multivariable models containing the criteria
as covariates, waist circumference and triglyceride
levels were independently associated with Si and IAF
and SCF areas (P < 0.001). Although insulin resistance
and central body fat are both associated with the
metabolic syndrome, IAF is independently associated
with all of the criteria, suggesting that it may have
a pathophysiological role. Of the NCEP criteria, waist
circumference and triglycerides may best identify insulin
resistance and visceral adiposity in individuals
with a fasting plasma glucose < 6.4 mmol/l
Body Mass Index Is Associated with Increased Creatinine Clearance by a Mechanism Independent of Body Fat Distribution
Context: Although obesity has been, in general, associated with glomerular hyperfiltration, visceral adiposity has been suggested to be associated with reduced glomerular filtration
β-Cell Loss and β-Cell Apoptosis in Human Type 2 Diabetes Are Related to Islet Amyloid Deposition
Amyloid deposition and reduced β-cell mass are pathological hallmarks of the pancreatic islet in type 2 diabetes; however, whether the extent of amyloid deposition is associated with decreased β-cell mass is debated. We investigated the possible relationship and, for the first time, determined whether increased islet amyloid and/or decreased β-cell area quantified on histological sections is correlated with increased β-cell apoptosis. Formalin-fixed, paraffin-embedded human pancreas sections from subjects with (n = 29) and without (n = 39) diabetes were obtained at autopsy (64 ± 2 and 70 ± 4 islets/subject, respectively). Amyloid and β cells were visualized by thioflavin S and insulin immunolabeling. Apoptotic β cells were detected by colabeling for insulin and by TUNEL. Diabetes was associated with increased amyloid deposition, decreased β-cell area, and increased β-cell apoptosis, as expected. There was a strong inverse correlation between β-cell area and amyloid deposition (r = −0.42, P < 0.001). β-Cell area was selectively reduced in individual amyloid-containing islets from diabetic subjects, compared with control subjects, but amyloid-free islets had β-cell area equivalent to islets from control subjects. Increased amyloid deposition was associated with β-cell apoptosis (r = 0.56, P < 0.01). Thus, islet amyloid is associated with decreased β-cell area and increased β-cell apoptosis, suggesting that islet amyloid deposition contributes to the decreased β-cell mass that characterizes type 2 diabetes
Adipocytokines as features of the metabolic syndrome determined using confirmatory factor analysis
Purpose: Confirmatory factor analysis (CFA) was used to test the hypothesis whether adipocytokines are associated with the risk factor cluster that characterizes the metabolic syndrome (MetS). Methods: Data from 134 nondiabetic subjects were analyzed using CFA. Insulin sensitivity (SI) was quantified using intravenous glucose tolerance tests, visceral fat area by computed tomography and fasting high-density lipoprotein, triglycerides, monocyte chemoattractant protein-1 (MCP-1), serum amyloid A (SAA), tumor necrosis factor (TNF)-α, adiponectin, resistin, leptin, interleukin (IL)-6, C-reactive protein (CRP), and plasminogen activator inhibitor (PAI)-1 were measured. Results: The basic model representing the MetS included six indicators comprising obesity, SI, lipids, and hypertension, and demonstrated excellent goodness of fit. Using multivariate analysis, MCP-1, SAA, and TNF-α were not independently associated with any of the MetS variables. Adiponectin, resistin, leptin, CRP, and IL-6 were associated with at least one of the risk factors, but when added to the basic model decreased all goodness-of-fit parameters. PAI-1 was associated with all cardiometabolic factors and improved goodness-of-fit compared with the basic model. Conclusions: Addition of PAI-1 increased the CFA model goodness of fit compared with the basic model, suggesting that this protein may represent an added feature of the MetS
Reduced Adipogenic Gene Expression in Thigh Adipose Tissue Precedes Human Immunodeficiency Virus-Associated Lipoatrophy
Context: The expression of adipogenic genes in sc adipose tissue has been reported to be lower among patients with HIV-associated lipoatrophy than HIV-uninfected controls. It is unclear whether this is a result or cause of lipoatrophy