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Biomedical subjects

M L Healy

Publications and source records attributed to M L Healy.

11 recordsLinked to original sources
PubMed2005

Effects of high-dose growth hormone on glucose and glycerol metabolism at rest and during exercise in endurance-trained athletes.

CONTEXT: Recombinant human-GH (r-hGH), in supraphysiological doses, is self-administered by athletes in the belief that it is performance enhancing. OBJECTIVE: The objective of this study was to determine whether r-hGH alters whole-body glucose and glycerol metabolism in endurance-trained athletes at rest and during and after exercise. DESIGN: This was a 4-wk double-blind placebo-controlled trial. SETTING: This study was conducted at St. Thomas Hospital (London, UK). PARTICIPANTS: Twelve endurance-trained male athletes were recruited and randomized to r-hGH (0.2 U/kg.d) (n = 6) or identical placebo (n = 6) for 4 wk. One (placebo group) withdrew after randomization. INTERVENTION: Intervention was conducted by randomization to r-hGH (0.2 U/kg x d) or identical placebo for 4 wk. MAIN OUTCOME MEASURES: Whole-body rates of appearance (Ra) of glucose and glycerol (an index of lipolysis) and rate of disappearance of glucose were measured using infusions of d-[6-6-2H2]glucose and 2H5-glycerol. RESULTS: Plasma levels of glycerol and free fatty acids and glycerol Ra at rest and during and after exercise increased during r-hGH treatment (P < 0.05 vs. placebo). Glucose Ra and glucose rate of disappearance were greater after exercise during r-hGH treatment (P < 0.05 vs. placebo). Resting energy expenditure and fat oxidation were greater under resting conditions during r-hGH treatment (P < 0.05 vs. placebo). CONCLUSIONS: r-hGH in endurance-trained athletes increased lipolysis and fatty acid availability at rest and during and after exercise. r-hGH increased glucose production and uptake rates after exercise. The relevance of these effects for athletic performance is not known.

Adult↗
PubMed2003

Psychological effects of withdrawal of growth hormone therapy from adults with growth hormone deficiency.

OBJECTIVE: Growth hormone (GH) is known to be required for physical well-being. Although it is also widely believed to be important for quality of life (QoL) and psychological health, there is less supportive evidence. The objective of this study was to investigate the psychological effects of discontinuation of GH replacement from adults with severe GH deficiency (GHD). DESIGN: A double-blind, placebo-controlled trial in which GH replacement therapy was discontinued for 3 months from 12 of 21 GH-deficient adults, where nine continued with GH replacement. PATIENTS: GH-treated adults (10 men, 11 women), all with severe GHD (peak GH < 7.7 mU/l on provocative testing), mean age 44.9 years (range 25-68 years). MEASUREMENTS: Semi-structured interviews were given at baseline and end-point plus questionnaires that included a new hormone-deficiency specific, individualized, QoL questionnaire (HDQoL), the General Well-being Index (GWBI), the Well-being Questionnaire (W-BQ12), the Short-Form 36 health status questionnaire (SF-36), the Nottingham Health Profile (NHP) and the General Health Questionnaire (GHQ). RESULTS: Three months after baseline the serum total IGF-I of placebo-treated patients fell from normal, age-related levels (mean 26.6 +/- 13.2 nmol/l) to levels indicative of severe GHD (11.6 +/- 6.6 nmol/l) (P<0.001). Psychological symptoms of GH withdrawal, reported in interviews at end-point by placebo-treated patients, included decreased energy, and increased tiredness, pain, irritability and depression. Patients who believed they knew which treatment they had received correctly identified the treatment (GH or placebo) at end-point (chi2=11.25, P<0.01). Significant between-treatment-group differences in change scores were found for SF-36 General Health (P<0.01), W-BQ12 Energy (P<0.01) and HDQoL do physically (P<0.05), indicating reduced general health, reduced energy and greater perceived impact of hormone deficiency on physical capabilities in the placebo-treated group at end-point relative to GH-treated patients. CONCLUSION: Withdrawal of GH treatment from adults with severe GH deficiency has detrimental psychological effects.

Adult↗
PubMed2003

Effect of growth hormone (GH) on glycerol and free fatty acid metabolism during exhaustive exercise in GH-deficient adults.

GH is an important regulator of fat metabolism at rest, but it is not known whether it regulates fat metabolism during exercise. To determine whether physiologic concentrations of GH influence fat metabolism during exercise, we randomized 16 GH-deficient adults, receiving long-term (mean duration, 5 yr) GH replacement, to either continue GH (n = 8) or receive identical placebo (n = 8) for a 3-month period. Metabolic studies, at rest, during and following exhaustive exercise were carried out at baseline and at the end of the 3 months. The rate of appearance of glycerol (glycerol Ra, an index of lipolysis) and free fatty acids (FFA, FFA Ra) and the rate of disappearance of FFA (FFA Rd) in the plasma were measured using infusions of (2)H(5)-glycerol and 1-(13)C-palmitic acid. Changes in body composition were assessed using dual-energy x-ray absorptiometry scanning and anthropometric measurements. In the baseline studies, exercise resulted in an increase in plasma glycerol and FFA concentrations, glycerol Ra, FFA Ra, and FFA Rd (P < 0.001). Three months of GH withdrawal resulted in reductions in plasma glycerol and FFA, glycerol Ra, FFA Ra, and FFA Rd at rest (P < 0.05 vs. baseline) and during exercise (P < 0.05 vs. baseline and vs. GH treated). Lean body mass decreased after 3 months of GH withdrawal, but total body fat, trunk fat, waist circumference, and the sum of skinfold thicknesses increased after 3 months of GH withdrawal (P < 0.05 vs. baseline and vs. GH treated). Fasting insulin and homeostasis model assessment of insulin resistance decreased after 3 months of GH withdrawal (P < 0.05 vs. baseline and vs. GH treated). In summary, GH withdrawal for 3 months resulted in reductions in release of glycerol and FFA into the circulation and uptake of FFA into the tissues during intense exercise. These changes were accompanied by reduced lean body mass and increased total body and trunk fat. Further studies are required to determine whether reduced mobilization of fat during exercise contributes to reduced exercise capacity and increased body fat in GH-deficient adults.

Absorptiometry, Photon↗
PubMed2003

High dose growth hormone exerts an anabolic effect at rest and during exercise in endurance-trained athletes.

The anabolic actions of GH in GH-deficient adults and children are well documented. Replacement with GH in such individuals promotes protein synthesis and reduces irreversible loss of protein through oxidation. Although GH is known to be self-administered by athletes, its protein metabolic effects in this context are unknown. This study was designed to determine whether 4 wk of high dose recombinant human GH (r-hGH) administration altered whole body leucine kinetics in endurance-trained athletes at rest and during and after 30 min of exercise at 60% of maximal oxygen uptake. Eleven endurance-trained male athletes were studied, six randomized to receive r-hGH (0.067 mg/kg.d), and five to receive placebo. Whole body leucine turnover was measured at rest and during and after exercise, using a 5-h primed constant infusion of 1-[(13)C]leucine, from which rates of leucine appearance (an index of protein breakdown), leucine oxidation, and nonoxidative leucine disposal (an index of protein synthesis) were estimated. Under resting conditions, r-hGH administration increased rate of leucine appearance and nonoxidative leucine disposal, and reduced leucine oxidation (P < 0.01). This effect was apparent after 1 wk, and was accentuated after 4 wk, of r-hGH administration (P < 0.05). During and after exercise, GH attenuated the exercise-induced increase in leucine oxidation (P < 0.05). There were no changes observed in placebo-treated subjects compared with the baseline study. We conclude that GH administration to endurance-trained male athletes has a net anabolic effect on whole body protein metabolism at rest and during and after exercise.

Adult↗
PubMed2001

The response of molecular isoforms of growth hormone to acute exercise in trained adult males.

Circulating GH consists of multiple molecular isoforms, all derived from the one gene in nonpregnant humans. To assess the effect of a potent stimulus to pituitary secretion on GH isoforms, we studied 17 aerobically trained males (age, 26.9 +/- 1.5 yr) in a randomized, repeat measures study of rest vs. exercise. Exercise consisted of continuous cycle ergometry at approximately 80% of predetermined maximal oxygen uptake for 20 min. Serum was assayed for total, pituitary, 22-kDa, recombinant, non-22-kDa, 20-kDa, and immunofunctional GH. All isoforms increased during, peaked at the end, and declined after exercise. At peak exercise, 22-kDa GH was the predominant isoform. After exercise, the ratios of non-22 kDa/total GH and 20-kDa GH/total GH increased and those of recombinant/pituitary GH decreased. The disappearance half-times for pituitary GH and 20-kDa GH were significantly longer than those for all other isoforms. We conclude that 1) all molecular isoforms of GH measured increased with and peaked at the end of acute exercise, with 22-kDa GH constituting the major isoform in serum during exercise; and 2) the proportion of non-22-kDa isoforms increased after exercise due in part to slower disappearance rates of 20-kDa and perhaps other non-22-kDa GH isoforms. It remains to be determined whether the various biological actions of different GH isoforms impact on postexercise homeostasis.

Adult↗
PubMed2001

Management strategies for an aging work force.

1. The demographic shift to an aging population has significant societal and cultural implications that carry over into the workplace. 2. The occupational and environmental health nurse needs to be aware of the risks associated with the aging process including physiological changes of aging, comorbidities and chronic diseases, and psychosocial factors as well as the impact those risks may have on work ability. 3. Health management strategies for an aging worker population include developing an older worker profile, creative job accommodations, and training programs. 4. The occupational and environmental health nursing scope of practice will require significant change for the profession to take a proactive approach to address this workplace transformation.

Aging↗
PubMed2000

Growth hormone (GH) effects on bone and collagen turnover in healthy adults and its potential as a marker of GH abuse in sports: a double blind, placebo-controlled study. The GH-2000 Study Group.

The effects of GH on bone remodeling in healthy adults have not been systematically investigated. An analysis of these effects might provide insights into GH physiology and might yield data useful for the detection of GH doping in sports. The aim of this study was to evaluate the effects of GH administration on biochemical markers of bone and collagen turnover in healthy volunteers. Ninety-nine healthy volunteers of both sexes were enrolled in a multicenter, randomized, double blind, placebo-controlled study and assigned to receive either placebo (40 subjects) or recombinant human GH (0.1 IU/kg day in 29 subjects and 0.2 IU/kg x day in 30 subjects). The treatment duration was 28 days, followed by a 56-day wash-out period. The biochemical markers evaluated were the bone formation markers osteocalcin and C-terminal propeptide of type I procollagen, the resorption marker type I collagen telopeptide, and the soft tissue marker procollagen type III. All variables increased on days 21 and 28 in the two active treatment groups vs. levels in both the baseline (P < 0.01) and placebo (P < 0.01) groups. The increment was more pronounced in the 0.2 IU/kg-day group and remained significant on day 84 for procollagen type III (from 0.53 +/- 0.13 to 0.61 +/- 0.14 kU/L; P < 0.02) and osteocalcin (from 12.2 + 2.9 to 14.6 +/- 3.6 UG/L; P < 0.02), whereas levels of C-terminal propeptide of type I procollagen and type I collagen telopeptide declined after day 42 and were no longer significantly above baseline on day 84 (from 3.9 +/- 1.2 to 5.1 +/-1.5 microg/L and from 174 +/- 60 to 173 +/- 53 microg/L, respectively). Gender-related differences were observed in the study; females were less responsive than males to GH administration with respect to procollagen type III and type I collagen telopeptide (P < 0.001). In conclusion, exogenous GH administration affects the biochemical parameters of bone and collagen turnover in a dose- and gender-dependent manner. As GH-induced modifications of most markers, in particular procollagen type III and osteocalcin, persist after GH withdrawal, they may be suitable markers for detecting GH abuse.

Adult↗
PubMed2000

Telecommuting: Occupational health considerations for employee health and safety.

1. Information technology has moved "work" out of a centralized location. Employees who telecommute pose significant challenges and considerations for the practice of occupational health nursing. 2. Employer and employee benefits associated with telecommuting are reportedly associated with high levels of job satisfaction. However, the occupational health and safety risks of this new work environment need to be fully assessed and understood. 3. The ergonomic controls to minimize the risk of repetitive motion injuries are the same for both office and home locations. Additional attention need to be paid to implementing risk controls for other physical hazards and psychosocial considerations, as well as personal safety and security issues. 4. The scope of occupational health nursing practice needs to remain dynamic, recognizing the impact new technologies have on the workplace, to continue to meet the needs of the changing workplace.

Health Personnel↗
PubMed1994

Laparoscopic splenectomy for idiopathic thrombocytopenic purpura.

Laparoscopic splenectomy was performed on eight patients with idiopathic thrombocytopenic purpura refractory to medical treatment. Preoperative infusion of immunoglobulin G gamma-globulin was used to boost the platelet count. Accessory spleens were sought by preoperative computed tomography and peroperative examination of the usual anatomical locations. Seven patients underwent successful laparoscopic splenectomy, with a mean postoperative stay of 3.6 days. One patient with an accessory spleen detected before operation but not during laparoscopy required conversion to open surgery for control of haemorrhage from the splenic hilum. Another patient had a transient pancreatic fistula. Laparoscopic splenectomy is feasible and sfe in patients with idiopathic thrombocytopenic purpura. Long-term results require evaluation as detection of accessory spleens can prove difficult during laparoscopy.

Adolescent↗