Biomedical subjects

Andrew A Dwyer

Publications and source records attributed to Andrew A Dwyer.

5 recordsLinked to original sources

PubMed2026

Health Service Delivery Outcomes From Nursing in Genomics: A Scoping Review of the Literature (2012-2025).

AIM: This study aimed to summarize the current state of the science for "health service delivery-oriented outcomes" from nursing in genomics (2012-2025). BACKGROUND: Nurses can play a vital role in increasing access to genomic healthcare and improving outcomes for patients, families, and communities. METHODS: We conducted a scoping review of the literature in four databases (2012-2025). Articles were categorized using the Cochrane Collaboration outcome domains and sub-domains to identify salient topics and synthesize findings. RESULTS: Of 11,646 retrieved articles, 66 publications reporting "health service delivery-oriented outcomes" were included for analysis. Identified articles spanned three sub-domains: "service delivery level," "related to research," and "societal or governmental." Within sub-domains, articles were further categorized into dimensions, the most prominent being "service utilization" under the "service delivery level" sub-domain. Studies were primarily from anglophone countries and near-evenly split into interventional and noninterventional studies. Studies reported that nurses working in multidisciplinary and/or interprofessional teams are a cost-effective means to increase access to genomic healthcare and reduce burden on genetic specialists. Nurses are incorporating genomics in various settings, including oncology, pharmacogenomics, genetic counseling, rare genetic diseases, and symptom science. CONCLUSION: Despite evidence of nurses contributing to health system delivery-oriented outcomes, evidence suggests that nurses are underutilized and underprepared in genomic healthcare. IMPLICATIONS FOR NURSING: A significant barrier to integrating genomics into nursing practice is a lack of foundational knowledge and genomic competency across nursing education, clinical practice, and nursing policymakers. IMPLICATIONS FOR NURSING POLICY: Nursing leadership spanning education, research, practice, and policy domains will be critical for integrating genomics in nursing practice and improving health system delivery-oriented outcomes.

Humans↗

PubMed2005

Increasing insulin resistance is associated with a decrease in Leydig cell testosterone secretion in men.

Insulin resistance is associated with low testosterone (T) levels in men, the mechanism of which is unclear. Thus, the aim of this study was to evaluate the hypothalamic-pituitary-gonadal axis in men with a spectrum of insulin sensitivity. Twenty-one men (aged 25-65 yr) had a glucose tolerance test and assessment of insulin sensitivity using a hyperinsulinemic-euglycemic clamp. Insulin sensitivity, expressed as the M value (milligrams per kilograms(-1) per minute(-1)), was calculated from the glucose disposal rate during the final 30 min of the clamp. Eighteen subjects had blood sampling every 10 min for 12 h to assess LH pulsatility. Hypogonadism was then induced with a GnRH antagonist, followed by sequential stimulation testing with GnRH (750 ng/kg, iv) and human chorionic gonadotropin (hCG; 1000 IU, im) to assess pituitary and testicular responsiveness, respectively. Nine subjects had normal glucose tolerance, nine had impaired glucose tolerance, and three had diabetes mellitus. There was a positive relationship between M and T levels (r = 0.46; P < 0.05). No relationship was seen between M and parameters of LH secretion, including mean LH levels, LH pulse amplitude, LH pulse frequency, and LH response to exogenous GnRH administration. In contrast, a strong correlation was observed between M and the T response to hCG (r = 0.73; P < 0.005). Baseline T levels correlated with the increase in T after hCG administration (r = 0.47; P < 0.05). During the clamp, T levels increased from a baseline level of 367 +/- 30 to 419 +/- 38 ng/dl during the last 30 min (P < 0.05). From these data we conclude that insulin resistance is associated with a decrease in Leydig cell T secretion in men. Additional studies are required to determine the mechanism of this effect.

Adult↗

PubMed2005

Relationship between testosterone levels, insulin sensitivity, and mitochondrial function in men.

OBJECTIVE: The goal of this study was to examine the relationship between serum testosterone levels and insulin sensitivity and mitochondrial function in men. RESEARCH DESIGN AND METHODS: A total of 60 men (mean age 60.5 +/- 1.2 years) had a detailed hormonal and metabolic evaluation. Insulin sensitivity was measured using a hyperinsulinemic-euglycemic clamp. Mitochondrial function was assessed by measuring maximal aerobic capacity (V(O2max)) and expression of oxidative phosphorylation genes in skeletal muscle. RESULTS: A total of 45% of subjects had normal glucose tolerance, 20% had impaired glucose tolerance, and 35% had type 2 diabetes. Testosterone levels were positively correlated with insulin sensitivity (r = 0.4, P < 0.005). Subjects with hypogonadal testosterone levels (n = 10) had a BMI >25 kg/m(2) and a threefold higher prevalence of the metabolic syndrome than their eugonadal counterparts (n = 50); this relationship held true after adjusting for age and sex hormone-binding globulin but not BMI. Testosterone levels also correlated with V(O2max) (r = 0.43, P < 0.05) and oxidative phosphorylation gene expression (r = 0.57, P < 0.0001). CONCLUSIONS: These data indicate that low serum testosterone levels are associated with an adverse metabolic profile and suggest a novel unifying mechanism for the previously independent observations that low testosterone levels and impaired mitochondrial function promote insulin resistance in men.

Adult↗

PubMed2004

Reversible kallmann syndrome, delayed puberty, and isolated anosmia occurring in a single family with a mutation in the fibroblast growth factor receptor 1 gene.

Kallmann syndrome (KS) is a clinically and genetically heterogeneous disorder. Recently, loss-of-function mutations in the fibroblast growth factor receptor 1 (FGFR1) gene have been shown to cause autosomal dominant KS. To date, the detailed reproductive phenotype of KS associated with mutations in the FGFR1 has yet to be described. We report a kindred comprising a male proband with KS and spontaneous reversibility, whose mother had delayed puberty and whose maternal grandfather isolated anosmia. The proband presented at age 18 yr with KS and was subsequently treated with testosterone (T) therapy. Upon discontinuation of T therapy, he recovered from his hypogonadotropic hypogonadism, as evidenced by a normal LH secretion pattern, sustained normal serum T levels, and active spermatogenesis. The three members of this single family harbor the same FGFR1 mutation (Arg(622)X) in the tyrosine kinase domain. This report demonstrates 1) the first genetic cause of the rare variant of reversible KS, 2) the reversal of hypogonadotropic hypogonadism in a proband carrying an FGFR1 mutation suggests a role of FGFR1 beyond embryonic GnRH neuron migration, and 3) a loss of function mutation in the FGFR1 gene causing delayed puberty.

Adult↗

PubMed2004

Acute stress masking the biochemical phenotype of partial androgen insensitivity syndrome in a patient with a novel mutation in the androgen receptor.

Hypogonadism has traditionally been classified as either hypogonadotropic or hypergonadotropic based on serum gonadotropin levels. However, when hypothalamic suppression of GnRH secretion occurs, it can mask an underlying hypergonadotropic state. In this report we document the unusual case of a 61-yr-old man with androgen insensitivity and coincidental functional hypogonadotropic hypogonadism (HH). Although functional HH is not a well-recognized entity in the male, major stress has been reported to cause transient suppression of the hypothalamic-pituitary-gonadal axis in men. The patient in question was noted to have undervirilization, minimal pubertal development, hypogonadal testosterone, and low gonadotropin levels consistent with congenital HH during a hospital admission for myocardial infarction. However, the patient had also had surgery for hypospadias, a clinical feature not typically part of the phenotypic spectrum of congenital HH. We therefore hypothesized that the combination of acute stress and chronic glucocorticoid administration for temporal arteritis induced transient HH in a patient with a disorder of sexual differentiation in whom gonadotropin levels would have otherwise been elevated. Using clinical, molecular, and genetic studies, the patient was found to have partial androgen insensitivity syndrome (PAIS) caused by a novel mutation (Ser(740)Cys) in the ligand-binding domain of the androgen receptor. Subsequent studies of the patient confirmed the characteristic gonadotropin and sex steroid abnormalities of PAIS. We describe for the first time a patient with PAIS presenting with a reversible hypogonadotropic biochemical profile triggered by an acute illness and corticosteroid therapy. This case highlights the necessity for caution when interpreting gonadotropin levels during acute stress.

Androgen-Insensitivity Syndrome↗