Biomedical subjects

Matthew Weiss

Publications and source records attributed to Matthew Weiss.

3 recordsLinked to original sources

PubMed2026

Climate Gradients and Habitat Discontinuity Structure Genetic Variation in a Spring-Specialist Plant.

BACKGROUND AND AIMS: Groundwater-dependent ecosystems support disproportionate biodiversity in arid regions, yet the population genetics of spring-specialist plants remains poorly understood. Here, we present the first species-wide genetic dataset for crimson monkeyflower (Mimulus verbenaceus, Phrymaceae), a spring-specialist plant distributed in seeps, springs, and associated riparian areas across desert regions of North America. We aim to relate landscape features and climate gradients to the spatial genetic structuring within this system. METHODS: Using genome-wide reduced representation sequencing data consisting of 10,760 SNPs from 175 individuals across 17 populations, we characterized the patterns of genetic differentiation and diversity. Population structure was assessed using ADMIXTURE and Principal Component Analysis. We examined the contributions of climate to range-wide genetic variation in crimson monkeyflower using redundancy analysis. KEY RESULTS: Patterns of genetic differentiation were more consistent with those of spring-specialist animal taxa than those of upland plants or generalist riparian plants. We found strong population structure at both broad regional scales and at fine local scales. While geographic and spatial structuring was a primary driver of genetic structure across all scales, riparian connectivity influenced local patterns of diversity, and adaptation to local climatic variation was more influential at regional scales, with temperature, relative humidity, and a monsoon-driven climate gradient contributing to genetic differentiation. CONCLUSIONS: Our findings highlight the distinctive association with isolated perennial groundwater sources, as well as climate gradients, with genetic variation in this spring-specialist plant. These findings suggest that spring-specialist plants deserve special consideration in ecological theory, management, and conservation.

Mimulus↗

PubMed2002

Managing conflicts of interest in the conduct of clinical trials.

The interaction between medical research and for-profit corporations is not new, but it has expanded considerably in recent years. Some of the recent trends may accelerate the research process, particularly when large clinical trials are required. However, a renewed commitment to the application of high ethical standards is essential to ensure that societal trust in research is not eroded, subjects enrolled in trials do not become merely a means to an end, and medical research is efficiently translated into clinical advances that will benefit future patients. This article focuses on the analysis of conflicts of interest in the conduct of clinical trials in both academic and community-based settings. Specifically, it discusses how the roles of research scientists and clinical practitioners differ and the importance of ensuring that participants' consent to enroll in clinical trials is not the result of confusion about the goals of an experimental treatment that may resemble clinical care. The article also discusses the potential conflicts of interest that can arise when clinicians stand to gain from enrolling their own patients as subjects in clinical trials and examines various instances in which disclosure of information regarding funding and compensation may serve to minimize such conflicts. This article emphasizes that to preserve the integrity of research and to protect the welfare of human subjects who enroll in trials, physicians should have adequate training in the conduct of research and be familiar with the ethics of research. When a physician has treated or continues to treat a patient who is eligible to enroll as a subject in a clinical trial conducted by the same physician, someone other than the treating physician should obtain the participant's informed consent. Finally, the article addresses disclosure of financial incentives and related funding issues.

Biomedical Research↗

PubMed2002

Surgical "placebo" controls.

OBJECTIVE: To set ethical guidelines on the use of surgical placebo controls in the design of surgical trials. BACKGROUND DATA: Ethical concerns recently arose from surgical trials where subjects in the control arm underwent surgical procedures that had the appearance of a therapeutic intervention, but during which the essential therapeutic maneuver was omitted. Although there are ethical guidelines on the use of a placebo in drug trials, little attention has been paid to the use of a surgical placebo control in surgical trials. METHODS: The Council on Ethical and Judicial Affairs developed ethical guidelines based on a wide literature search and consultation with experts. RESULTS: Surgical placebo controls should be limited to studies of new surgical procedures aimed at treating diseases that are not amenable to other surgical therapies, and are reasonably anticipated to be susceptible to substantial placebo effects. If the standard nonsurgical treatment is efficacious and acceptable to the patient, then it must be offered as part of the study design. CONCLUSIONS: Surgical placebo controls should be used only when no other trial design will yield the requisite data and should always be accompanied by a rigorous informed consent process and a careful consideration of the related risks and benefits. The recommended ethical guidelines were adopted as AMA ethics policy and are now incorporated in the AMA's Code of Medical Ethics.

Clinical Trials as Topic↗