Biomedical subjects
D McHugh
Publications and source records attributed to D McHugh.
Cross-sectional age differences in body composition in persons 60+ years of age.
BACKGROUND: There is little information for age differences in body composition in elderly people > 65 years of age, especially for those > 80 years. As the proportion of people older than 65 years is expected to nearly double during the next few decades, this information is needed. METHODS: Age differences in body composition and anthropometry were examined in 316 men and women aged 60 to 95 years. Multiple components of body composition were quantified using dual energy X-ray absorptiometry and isotope dilution methods, and expressed in molecular and cellular models. Analysis of variance was used to test for differences between age groups 60 to 70, 71 to 80, and > 80 years in each sex. Body composition components were regressed on age, controlling for knee height, fat-free mass, or total body fat. Age-adjusted correlations were calculated with anthropometric variables. RESULTS: Fat-free mass (FFM), body cell mass (BCM), and appendicular skeletal muscle (ASM) decreased with age in both sexes. ASM decreased relative to FFM in both the men and the women, while BCM decreased relative to FFM in the women only. Total fat mass and percent body fat decreased with age in the women, but not in the men. Body fat distribution did not appear to change with age. Anthropometric indices, muscle area and waist/hip ratio, had low correlations with muscle mass and fat distribution. CONCLUSIONS: "Sarcopenia," or muscle loss, continues to occur into old age, and may have significant impacts on physical function and health status. New anthropometric techniques are needed for assessing muscle loss with age.
Inhibition of delayed rectifier K(+)-current by levcromakalim in single intestinal smooth muscle cells: effects of cations and dependence on K(+)-flux.
1. Whole-cell voltage-clamp recordings were made from single smooth muscle cells isolated from the longitudinal layer of the guinea-pig small intestine. 2. Levcromakalim ((-)Ckm) inhibited delayed rectifier K-current (IK(DR)) and induced a voltage-independent K-current (IK(-Ckm)). Both effects were inhibited similarly by glibenclamide. In some cells, however, IK(-Ckm) could be induced without any effect on IK(DR). 3. Ba2+ caused a voltage-dependent block of IK(-Ckm). The IC50 was 0.2 mM at -40 mV (6 cells), but at 0 mV 2 mM Ba2+ caused only a 26 +/- 7% inhibition (n = 5). Ba2+ had much less effect on IK(DR), 2 mM Ba2+ having no inhibitory effect on current elicited by depolarization to -30 mV (n = 6) or 0 mV (n = 5). 4. Low concentrations of Zn2+ blocked IK(-Ckm) while having little effect on IK(DR). Zn2+ (40 microM) caused a 77 +/- 1% reduction of IK(-Ckm) at -30 mV (n = 4) but IK(DR) was inhibited by only 10 +/- 3% at the same voltage (n = 4). 5. Inward current amplitudes were compared in 135 mM Rb+ and 135 mM K+ bath solutions. (-)Ckm-activated Rb(+)-current was only 4% of the K(+)-current, whereas delayed rectifier Rb(+)-current was larger than K(+)-current. 6. (-)Ckm did not inhibit IK(DR) if IK(-Ckm) was blocked. In the presence of 2 mM Ba2+ or 135 mM Rb+, (-)Ckm did not induce current nor did it inhibit the delayed rectifier. When [Rb+]o was 25 mM and [K+]J was 130 mM, (-)Ckm elicited outward current and inhibited outward delayed rectifier current (at voltages positive of the reversal potential) but it did not elicit inward current or inhibit inward delayed rectifier current (at voltages negative of the reversal potential).7. These experiments indicate that (-)Ckm-activated K channels are more sensitive to inhibition by Ba2+and Zn2+ and pass inward Rb+ current less well than delayed rectifier K channels. They also suggest that (-)Ckm does not modulate delayed rectifier K channels directly or via an intermediate protein but that the inhibitory effect of (-)Ckm on IK(DR) arises as a consequence of K+-flux through (-)Ckm activated K channels.
Irradiation of rabbit retina with diode and Nd:YAG lasers.
AIMS: This study was carried out to compare the effects of continuous wave infrared laser radiation on pigmented and albino rabbit retinas at two wavelengths: 810 nm (diode) and 1064 nm (Nd:YAG). METHODS: Transpupillary laser pulses were applied with a spot size of 200 microns and durations of 200 ms (pigmented rabbits) and 0.5-1 s (albino rabbits). Light and electron microscopic analyses were performed immediately after exposure. RESULTS: In pigmented rabbits, threshold lesions were induced using a power of 100 mW with the diode and 200 mW with the Nd:YAG lasers. Damage was incurred by the retinal pigment epithelium with extension into the superficial and mid choroid posteriorly and into the outer retina anteriorly. In albino rabbits, lesions of comparable anteroposterior extension were identified using a power of 10 W with the Nd:YAG laser. Using diode laser irradiation, a maximum power output of 1.2 W failed to produce discernible lesions. CONCLUSIONS: The observed patterns of morphological damage are produced by complex tissue radiation interactions. In pigmented animals, this was primarily related to absorption of radiant energy by melanin within the retinal pigment epithelium and the choroidal melanocytes. In albino rabbits, laser induced effects occurred as a consequence of multiple scattering, together with absorption within haemoglobin and possibly also within tissue water. The data obtained provide further insight into the biological mechanisms arising from retinal photocoagulation with near infrared lasers.
Experimental long-term vitreous replacement with purified and nonpurified perfluorodecalin.
Explore the source record for details and available documents.
Enhancement of pain control with ketorolac tromethamine in patients with sickle cell vaso-occlusive crisis.
Twenty one patients with sickle cell disease admitted to the hospital with the pain of vaso-occlusive crisis (VOC) were treated by continuous IV infusion of ketorolac or normal saline for up to 5 days. All patients received supplemental IM injections of meperidine, 100 mg, as necessary, but not more frequently than every 3 hr. Over the 5 days the ketorolac treated patients (KT) required 33% less meperidine than did the placebo treated patients (PL), P = 0.04, and had significantly better pain relief as assessed by categorical, visual analog, and pain relief scales. By the end of 5 days infusions had been discontinued in six KT and one PL. The time to discontinuation of the infusion was significantly shorter in KT, (P = 0.009). The median duration of hospital stay from the start of treatment was 3.3 days for KT and 7.2 days for PL, P = 0.027. Adverse events were mainly related to the digestive system. This study showed that continuous infusion of ketorolac significantly reduced total meperidine requirement and that the analgesia produced by this combination was superior to that produced by meperidine alone. Further evaluation of this drug in the management of sickle cell VOC is warranted.
Contact diode laser cyclo-photocoagulation for refractory glaucoma. A pilot study.
Initial experience with non-contact diode cyclo-photocoagulation for refractory glaucoma has shown positive results. Diode laser irradiation applied via a contact probe results in greater transmission through the sclera and delivery of more energy to the ciliary body. A trial was performed to evaluate the effects of contact diode cyclo-photocoagulation. A total of 12 patients with glaucoma due to conditions such as central retinal vein occlusion were treated. A mean of 22 pulses (810 nm) with powers of up to 2 W and of 2 s duration were applied via a fibre-optic delivery system and a contact probe. The mean intra-ocular pressure dropped from 42.3 to 13.6 mmHg over 3 months. Four patients required retreatment. Three patients had side effects that included hyphaema, anterior fibrinous uveitis and pupil block. In conclusion, contact diode cyclo-photocoagulation had a significant ocular hypotensive action in the treatment of refractory glaucoma. As compared with non-contact diode cyclo-photocoagulation, the contact modality produced more marked non-therapeutic side effects.
Long-term results of ab externo neodymium:YAG cyclophotocoagulation.
Neodymium: YAG cyclophotocoagulation (CPC) was performed in 128 eyes of 123 patients with refractory glaucoma. In each eye, 40 burns delivered with energy of up to 7 J were placed 1.5 mm behind the limbus in a 360 degrees pattern. The minimal follow-up period was 24 months, with the mean being 36.9 (range, 24-84; SD, 5.8) months. The mean intraocular pressure was 35.0 (range 23-54; SD, 12.2) mmHg preoperatively, 20.6 (range 15-24; SD, 3.5) mmHg after 1 year, and 20.2 (range 12-24; SD, 8.1) mmHg after 2 years. A total of 25 eyes (19.5%) lost 2 or more lines in visual acuity. Success was defined as a lowering of intraocular pressure by > 30% and a decrease in visual acuity of < 2 Snellen lines. By this definition the success rate was 52.4%. There was no correlation with either the diagnosis, the stage of the disease, or the pigmentation of the trabecular meshwork, although patients with secondary traumatic or uveitic glaucoma tended to be less responsive to CPC. The most common acute complication of treatment was transient corneal edema. Phthisis bulbi developed in 1 eye (0.8%). In conclusion, CPC achieved satisfactory long-term control of intraocular pressure in the majority of patients with severe late-stage glaucoma.
Bone mineral in southwest Native American women.
Explore the source record for details and available documents.
Body composition in the elderly using multicompartmental methods.
Explore the source record for details and available documents.
A programmable Doppler string test object.
A prototype water filled ultrasound string test object is presented for performance checks on Doppler ultrasound systems. The string motion produces realistic and reproducible Doppler wave forms on the system by means of a programmable stepper motor. Wave forms can be generated using a computer, and programmed into the device. The test object can be used to check Doppler calculation parameters, such as pulsatility index and resistance index, as well as range gate registration and wall filter function. The test object is water filled, and the lack of attenuation did prove to be a problem on some systems. The object was tested using five different duplex and colour scanners, and found to be sufficiently reproducible for use as a field test object for Doppler ultrasound machines. The device is compact and portable, making it suitable for checks in the field for both longterm monitoring of performance and inter-machine comparisons.
Current uses of ophthalmic lasers.
Current laser treatments are quick, relatively painless, and well tolerated. Some ophthalmic techniques can be performed only by laser while others have a lower morbidity than alternative treatments. Peripheral retinal photocoagulation and focal photocoagulation now offer greatly improved visual prognosis for diabetic patients with proliferative diabetic retinopathy or diabetic macular disease. Selected cases of macular degeneration may be treated by focal laser photocoagulation. The role of lasers in treating sub-retinal neovascular membranes is limited by the extent and location of the membrane at presentation and the high risk of recurrence after treatment. Patients with distorted vision must be referred urgently for specialist ophthalmic assessment. Flat retinal holes and tears may be sealed by laser therapy, thus preventing retinal detachment. Short pulsed neodymium-YAG photodisruptive capsulotomy effectively clears the visual axis of thickened posterior lens capsule after cataract surgery. Short pulsed neodymium-YAG photodisruptive iridotomy may be used to treat and prevent angle closure glaucoma. Laser trabeculoplasty aids the control of open angle glaucoma. Research is continuing into the role of other lasers in managing open angle glaucoma and of photoablative lasers in treating refractive errors and superficial corneal disorders.
Comparison of the efficacy and safety of ketorolac and meperidine in the relief of dental pain.
A single-dose, randomized, double-blind study of parallel design was conducted to determine the analgesic efficacy and safety of ketorolac tromethamine in patients who experience moderate or severe pain after the surgical removal of three or more third molars, one of which was a bony-impacted mandibular molar. Meperidine hydrochloride was used as the control analgesic. In this 8-hour study, assessments were made of pain intensity, pain relief, and overall rating of the medication in 145 patients, each of whom had received an intramuscular injection of 10 mg, 30 mg, or 90 mg of ketorolac, or 50 mg or 100 mg of meperidine. The summed pain intensity and total pain relief scores showed that, at 3 and 8 hours, the effectiveness of 30 mg of ketorolac was similar to that of 90 mg ketorolac and that both of these doses were significantly more efficacious than 10-mg ketorolac, 50-mg meperidine, or 100-mg meperidine. Patients who received 30 mg or 90 mg of ketorolac gave the study medication significantly higher ratings overall than did patients who received 50 mg or 100 mg of meperidine. Significantly fewer patients treated with ketorolac reported adverse events in comparison with those treated with meperidine (17% and 59%, respectively), which suggests that it possesses a better therapeutic index than meperidine. Thus, ketorolac appears to represent an important advance in analgesic therapy.
The reversal of extrapyramidal side effects with SCH 39166, a dopamine D1 receptor antagonist.
Explore the source record for details and available documents.
Pseudophakic retinal detachment.
A total of 93 cases of pseudophakic retinal detachment are reported. The present study showed that vitreous loss had occurred during cataract surgery in 28% of eyes, indicating that anterior segment complications are an important contributory factor to aphakic retinal detachment in these cases. There was impairment of the retinal view in 46% of eyes, and in 22.5% no retinal breaks could be identified. The main factor responsible for poor visibility was inadequate pupillary dilatation, which was found particularly in association with the use of iris-supported lenses. Detachment of the macula was unexpectedly found to occur in as many as 88% of cases. Reattachment of the retina either by conventional detachment procedures or by pars plana vitrectomy was achieved in 76.3% of eyes. Complications directly attributable to the presence of an intraocular lens (such as dislocation or haemorrhage) are described. Failure of surgery was more likely to occur in eyes exhibiting a poor fundal view, in which the detection of retinal breaks was difficult. The best results were achieved in eyes in which posterior-chamber lenses had been implanted.
Tumour size as a prognostic factor in carcinoma of the cervix: assessment by transrectal ultrasound.
Transrectal ultrasound (TRUS) was used to measure tumour size in patients with carcinoma of the cervix and to assess its prognostic significance. Clinical staging was conducted and at the time of examination under anaesthesia, TRUS was used to assess maximum transverse diameter of the tumour. Eighty-one patients were studied. FIGO stages were 1B 34 patients, IIA seven patients, IIB 31 patients, IIIA two patients and IIIB seven patients. Mean tumour diameters by stage were IB 37 mm, IIA 37 mm, IIB 49 mm, IIIA 42 mm and IIIB 50 mm. There was a significant correlation between size and stage (p = 0.001). With a median follow-up of 18 months, 16 relapses have occurred. The actuarial relapse rates at median follow-up by stage were IB 10%, IIA 17%, IIB 22%, IIIA 0% and IIIB 35%. The actuarial relapse rates by size grouping at median follow-up were less than 30 mm 0%, greater than 30 and less than 40 mm 11%, greater than 40 and less than 50 mm 22%, and greater than 50 mm 38%. There was a significant difference between the mean recorded size of the tumours in the relapsed group and the relapse-free group (p = 0.02). Despite the small number of patients and short follow-up, tumour size as measured by TRUS appears to predict relapse.