Animal model study with mechanistic findings on arrhythmia reduction; lacks human validation and hard clinical outcomes needed for stronger evidence grading.
In vitro mechanistic study demonstrating enhanced probiotic metabolite activity against colorectal cancer cells and angiogenesis, but lacking in vivo efficacy data, clinical endpoints, or human translation.
A mechanistic, preclinical mouse study raising a question about phenol's role in metabolism and body composition; findings need confirmation in humans and disease models.
Descriptive comparative immunohistochemistry study raising mechanistic questions about CREB phosphorylation regulation in primate versus human prostate tissue, without clinical outcome data or functional validation.
A sound in vivo model study demonstrating clear biological effects of a natural extract on metabolic markers, but limited to a non-mammalian organism and surrogate endpoints with no human data.
Retrospective, non-randomized study with acknowledged selection bias and baseline imbalances; propensity score adjustment did not find mortality difference, but renal injury association lacks causal evidence and requires prospective confirmation.
An uncontrolled animal model study demonstrating mechanistic features of obesity-asthma interaction; descriptive findings in a single species without human validation or clinical outcome data.
Single-centre observational cohort study with exploratory multivariable analyses of prognostic factors in a small sample; the authors acknowledge potential selection bias and call for prospective validation, placing this in hypothesis-generating territory rather than confirmatory evidence.