Search PubMed⌕ Search

Biomedical subjects

M E Gordon

Publications and source records attributed to M E Gordon.

At least 19 recordsLinked to original sources
PubMed2006

Oral and intravenous carbohydrate challenges decrease active ghrelin concentrations and alter hormones related to control of energy metabolism in horses.

This study tested the hypothesis that grain and intravenous dextrose challenges would alter plasma concentrations of active ghrelin, adiponectin, leptin, glucose, insulin, and cortisol in Standardbred mares. To deliver 0.5 g of glucose (dextrose solution for the intravenous test)/kg of BW, mares received intravenous dextrose (50% solution) or oral grain administration in 2 trials. In response to the oral grain challenge, plasma glucose and insulin concentrations increased (P < 0.001) by 56 and 802%, respectively. Plasma ghrelin concentration initially decreased (P < 0.001) by 40%, then subsequently increased (P < 0.05) from its nadir by 259%. Plasma leptin concentration decreased (P = 0.002) 17% compared with baseline. There was no change (P = 0.34) in plasma adiponectin concentration in response to oral grain challenge; however, plasma cortisol concentrations decreased (P < 0.001) by 24%. In response to the intravenous dextrose challenge, plasma glucose and insulin concentrations increased (P < 0.001) by 432 and 395%, respectively. Plasma active ghrelin concentration initially decreased (P < 0.001) by 56%, then subsequently increased (P < 0.001) from its nadir by 314%. Plasma leptin concentration also increased (P < 0.001) by 33% compared with baseline. There was no change (P = 0.18) in plasma adiponectin concentration throughout the dextrose challenge. Plasma cortisol concentration increased (P = 0.027) by 20%. Hence, oral grain and intravenous nutrient challenges have the ability to alter variables potentially related to energy metabolism in mares, with acute changes in glucose and insulin possibly modulating changes in ghrelin and leptin.

Adiponectin↗
PubMed2005

Diurnal variation of ghrelin, leptin, and adiponectin in Standardbred mares.

Twelve Standardbred mares underwent blood sampling for 24 h to test the hypothesis that there is diurnal variation of humoral mediators of peripheral energy balance including active ghrelin, adiponectin, leptin, glucose, insulin, and cortisol. The experiment was conducted under acclimated conditions. Grass hay and pelleted grain were provided at 0730 and 1530. Plasma concentrations of active ghrelin and leptin concentrations both peaked (47.3 +/- 6.5 pg/ mL and 5.9 +/- 1.1 ng/mL, respectively; P < 0.05) at 1550, 20 min after feeding. Active ghrelin decreased (P < 0.05) to 28.9 +/- 4.5 pg/mL overnight. The nadir of leptin (4.6 +/- 0.9 ng/mL) occurred at 0650. Neither hormone showed variation (P > 0.05) after the morning feeding. Plasma glucose and insulin concentrations increased (P < 0.05) in response to feeding; however, the morning responses (glucose = 96.9 +/- 2.6 mg/dL; insulin = 40.6 +/- 7.3 uIU/mL) were greater (P < 0.05) than the afternoon responses (glucose = 89.9 +/- 1.8 mg/dL; insulin = 23.2 +/- 4.3 uIU/mL at 180 and 60 min after feeding, respectively). Cortisol concentrations increased (P < 0.05) during the morning hours, but did not respond to feeding, whereas adiponectin concentrations remained stable throughout the study. Hence, active ghrelin and leptin may be entrained to meal feeding in horses, whereas adiponectin seems unaffected. We concluded that there seems to be a diurnal variation in glucose and insulin response to a meal in horses. Furthermore, elevated glucose and insulin concentrations resulting from the morning feeding may be responsible for the increase in leptin concentration in the afternoon.

Adiponectin↗
PubMed1998

Efficacy and safety of the ProTek (Vifilcon A) therapeutic soft contact lens after photorefractive keratectomy.

PURPOSE: To test the ProTek (Vifilcon A) therapeutic soft contact lens in the alleviation of post-photorefractive keratectomy pain, its effect on epithelial healing, and its safety. METHODS: Forty-seven consecutive eligible patients undergoing unilateral excimer laser photorefractive keratectomy for myopia were randomly assigned to receive standard postoperative care with or without the use of a ProTek soft contact lens. Patients prospectively graded a self-administered 5-point scale for pain and a 4-point scale for abnormal sensations at 4, 8, 12, 16, and 20 hours after surgery. They also recorded the type and dose of all medications taken during that time period. All patients were examined on the first and third days after surgery. The lenses were worn continuously for 3 days. RESULTS: The soft contact lens group (n = 24) disclosed a statistically significant (P < .05) reduction in pain intensity and abnormal sensations that was greatest at 8, 12, 16, and 20 hours postoperatively. Compared with control patients (n = 23), the soft contact lens group showed significant decreased dependence on most pain medications after the 12th hour (P < .05) and faster epithelial healing (P = .03). However, one case of bacterial keratitis, two cases of subepithelial infiltrates, and seven cases of contact lens intolerance were present in the soft contact lens group. CONCLUSIONS: The ProTek therapeutic soft contact lenses were effective in decreasing pain and other related abnormal sensations after excimer photorefractive keratectomy. They decreased dependence on pain medications and hastened epithelial healing but were not well tolerated in some patients.

Adult↗
PubMed1993

A comprehensive algorithm for determining whether a run-in strategy will be a cost-effective design modification in a randomized clinical trial.

In randomized clinical trials, poor compliance and treatment intolerance lead to reduced between-group differences, increased sample size requirements, and increased cost. A run-in strategy is intended to reduce these problems. In this paper, we develop a comprehensive set of measures specifically sensitive to the effect of a run-in on cost and sample size requirements, both before and after randomization. Using these measures, we describe a step-by-step algorithm through which one can estimate the cost-effectiveness of a potential run-in. Because the cost-effectiveness of a run-in is partly mediated by its effect on sample size, we begin by discussing the likely impact of a planned run-in on the required number of randomized, eligible, and screened subjects. Run-in strategies are most likely to be cost-effective when: (1) per patient costs during the post-randomization as compared to the screening period are high; (2) poor compliance is associated with a substantial reduction in response to treatment; (3) the number of screened patients needed to identify a single eligible patient is small; (4) the run-in is inexpensive; (5) for most patients, the run-in compliance status is maintained following randomization and, most importantly, (6) many subjects excluded by the run-in are treatment intolerant or non-compliant to the extent that we expect little or no treatment response. Our analysis suggests that conditions for the cost-effectiveness of run-in strategies are stringent. In particular, if the only purpose of a run-in is to exclude ordinary partial compliers, the run-in will frequently add to the cost of the trial. Often, the cost-effectiveness of a run-in requires that one can identify and exclude a substantial number of treatment intolerant or otherwise unresponsive subjects.

Algorithms↗
PubMed1991

Gastrointestinal and other vulnerabilities for geriatric globetrotters.

An awareness of the journey's destination and the consequential events along the way will better enhance our diagnoses and in turn sustain our elder "homo turisticus," no longer an endangered species but worthy of our continued compassionate care while enjoying their longevity. All potential treacheries must be assessed by each elderly traveler. It may be the first of many trips or the last opportunity to view and relate to the sequoia's longevity, hike the Scottish highlands, view the game of the Serengeti, explore the Nordic fjords, indulge in the Patagonian scenes of the Iguazú falls, seek the habitats of the Galápagos tortoise, partake of the photograph opportunities of Papua-New Guinea, or finalize that "last" business contract in the Orient. With consideration of these many vulnerabilities and potential hazards, why then undertake the journey? Perhaps our geriatric globetrotters give credence to the age-old saying (of unknown origin) "Running water never freezes."

Aged↗
PubMed1990

A musculoskeletal model of the human lower extremity: the effect of muscle, tendon, and moment arm on the moment-angle relationship of musculotendon actuators at the hip, knee, and ankle.

We have developed a musculoskeletal model of the human lower extremity for computer simulation studies of musculotendon function and muscle coordination during movement. This model incorporates the salient features of muscle and tendon, specifies the musculoskeletal geometry and musculotendon parameters of 18 musculotendon actuators, and defines the active isometric moment of these actuators about the hip, knee, and ankle joints in the sagittal plane. We found that tendon slack length, optimal muscle-fiber length, and moment arm are different for each actuator, thus each actuator develops peak isometric moment at a different joint angle. The joint angle where an actuator produces peak moment does not necessarily coincide with the joint angle where: (1) muscle force peaks, (2) moment arm peaks, or (3) the in vivo moment developed by maximum voluntary contractions peaks. We conclude that when tendon is neglected in analyses of musculotendon force or moment about joints, erroneous predictions of human musculotendon function may be stated, not only in static situations as studied here, but during movement as well.

Ankle Joint↗
PubMed1990

Bicarbonate-buffered lidocaine-epinephrine-hyaluronidase for eyelid anesthesia.

A double-masked, randomized clinical trial was conducted to determine if subcutaneous eyelid injections of a bicarbonate-buffered lidocaine-epinephrine-hyaluronidase mixture were less painful than unbuffered injections. Twenty-one patients received both buffered (pH = 7.4) and unbuffered (pH = 4.6) injections. After each injection, patients recorded pain on a scale of 0, "no pain," to 10, "severe pain." Mean pain score for buffered injections was 2.0 versus 4.1 for unbuffered injections (P = 0.0003). Seventeen (81%) of 21 patients ranked the buffered injection less painful. Use of a bicarbonate-buffered lidocaine-epinephrine-hyaluronidase mixture is effective in making ophthalmic anesthesia less painful.

Adult↗
PubMed1988

Travails of travel. Subtle and obscure causes of illness.

Knowledge of patients' travel history is an important facet of diagnosis. Malaria, Chagas' disease, toxoplasmosis, Lyme disease, arboviruses, and many other relatively unusual diseases can be contracted while the patient is traveling, and the symptoms, which may mimic another disease, may not become obvious until the patient returns. The Roman philosopher Marcus Aurelius Antoninus alerts us to easier resolutions of our daily diagnostic dilemmas: "Look within and let neither the peculiar quality of anything nor its value escape thee."

Communicable Disease Control↗
PubMed1986

Natural history of retinal pigment epithelial detachments in age-related macular degeneration.

The natural history of 100 eyes of 93 patients with retinal pigment epithelial detachment (PED) and bilateral age-related macular degeneration (AMD) was retrospectively studied for a minimum of 12 months in the offices of Retina Consultants, Ltd. Detachment was defined as serous in 46 eyes, turbid in 12 eyes, hemorrhagic without evident neovascular membrane (NVM) in 20 eyes, and hemorrhagic with angiographically proven NVM in 17 eyes. Final visual results demonstrated visual acuity of 20/200 or worse in 33% of serous PED, 83% of turbid PED, and 89% of hemorrhagic PED. Despite strict inclusion criteria, 26% of serous PED developed NVM by one year and 49% of serous PED developed NVM by three years. Variables associated with NVM development in serous PED include older patient age, larger detachment size, presence of subretinal fluid at initial examination, and disciform scar in the fellow eye at presentation.

Age Factors↗
PubMed1985

Neovascular glaucoma after intracapsular and extracapsular cataract extraction in diabetic patients.

A retrospective study of the rate of development of neovascular glaucoma after cataract extraction in 242 eyes of 186 diabetic patients identified neovascular glaucoma in 13 of 146 eyes (8.9%) after intracapsular extraction, in two of 17 eyes (11.8%) after extracapsular extraction with primary capsulotomy, and in zero of 53 eyes after extracapsular extraction without capsulotomy. The incidence of neovascular glaucoma was significantly lower in patients who underwent extracapsular extraction with preservation of an intact posterior capsule than in those undergoing intracapsular cataract extraction (P less than .01) or extracapsular cataract extraction with primary capsulotomy (P less than .05).

Aged↗