Search PubMed⌕ Search

Biomedical subjects

G Young

Publications and source records attributed to G Young.

At least 145 records · Page 8Linked to original sources
PubMed1994

Evaluation of chronic foot pain.

Chronic pain problems and the resultant loss of function and productivity are major problems facing medicine today. Diagnosis of the underlying cause of the pain often eludes our best efforts. Unfortunately, part of the problem stems from the lack of a systematic and logical approach to the evaluation of patients with chronic pain. This article details the systematic approach used at the Intermountain Center for Podiatric Excellence and reviews the current literature on the subject. The evaluation system is driven by the differential diagnosis and includes psychosocial evaluation as indicated. This system was developed with the goal of maximizing diagnostic precision while minimizing costs.

Diagnosis, Differential↗
PubMed1993

Translocation (Y;1)(q12;q21) in acute leukemia.

This report documents one patient with myelodysplasia evolving into acute leukemia who showed a t(Y;1) translocation confirmed by in situ hybridization. Most of the q arm of the Y chromosome was translocated to an additional q arm of chromosome 1, resulting in trisomy 1q. To our knowledge only four other cases with this t(Y;1) have been reported.

Adult↗
PubMed1993

Changes in intra- or extracellular pH do not mediate P-glycoprotein-dependent multidrug resistance.

P-glycoprotein (Pgp)-mediated multidrug resistance (MDR) is thought to result from active extrusion of lipid-soluble, titratable chemotherapeutic agents. Given the lack of demonstration of coupling between ATP hydrolysis and drug transport, the resistance to chemically unrelated compounds, and findings of elevated intracellular pH (pHi), it has been proposed that reduced intracellular accumulation of drugs in MDR is due to changes in the pH difference across the plasma membrane. Elevation of pHi or decrease in local extracellular pH (pHo) could reduce the intracellular accumulation of the protonated chemotherapeutic drugs and account for Pgp-mediated MDR. Alternatively, changes in pHi or pHo could increase drug efflux by other mechanisms, such as coupled transport involving H+ or OH-, or allosteric effects on Pgp or other proteins. Both mechanisms could operate independently of the charge of the substrate. The possibility of a role of pHi in drug efflux is important to test because of the clinical significance of the phenomenon of MDR of tumors. We tested this hypothesis and found that MDR can occur in cells with low, normal, or high pHi. Further, resistant cells exhibited reduced steady-state drug accumulation and increased efflux without changes in local pHo. Finally, acute changes in pHi had no appreciable effect on Pgp-mediated drug efflux. We conclude that Pgp-mediated MDR is not a consequence of changes in pHi or pHo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Effects of hypophysectomy on coho salmon interrenal: maintenance of steroidogenic pathway and restoration of in vitro responsiveness to adrenocorticotropin after handling.

The role of the pituitary in regulating interrenal activity in coho salmon (Oncorhynchus kisutch) was examined using short- (1 week) or long- (10 week) term hypophysectomized (Hx) animals. In experiments in which Hx animals were injected with ovine growth hormone (oGH), triiodothyronine, or vehicle, plasma cortisol was significantly lower (close to non-detectable, 1 ng/ml) in vehicle-injected or hormone-treated short- and long-term Hx animals compared to vehicle-treated sham-operated (SO animals). Treatment of long-term Hx animals with oGH led to a significant increase in plasma cortisol, in comparison to other Hx groups. Interrenal responsiveness to ACTH or cAMP was not consistently affected by hypophysectomy or hormone treatment. Pregnenolone-supported cortisol production by tissue from Hx groups was at least as great as that by tissue from SO animals; production by tissue from GH-treated, long-term Hx animals was significantly greater than that by tissue from Hx or SO animals. Similar experiments utilizing handling stress (handling and anesthesia) instead of hormone injection as a variable revealed that the response of tissue from Hx animals to ACTH or cAMP was significantly reduced in the absence of handling in comparison with SO animals. However, utilization of pregnenolone as a substrate by tissue from Hx animals was no different from that by tissue from SO animals and was independent of handling. These results indicate that the maintenance of the steroid-biosynthetic pathway is pituitary independent. The decrease in tissue responsiveness to ACTH or cAMP in undisturbed Hx animals may be partially attributable to: (1) the absence of nonpituitary/nonpituitary-mediated factors that are stimulated by handling and which probably upregulate ACTH receptors and mediating systems; and/or (2) to the presence of inhibitory factors which are decreased after handling.

Adrenocorticotropic Hormone↗
PubMed1993

Water properties of hydrogel contact lens materials: a possible predictive model for corneal desiccation staining.

A set of properties of the water contained within hydrogel contact lens materials was determined with the aim of developing a model which would predict the propensity of a hydrogel contact lens material to induce corneal desiccation staining. We postulated that materials containing a larger proportion of water with the properties of bulk water would tend to induce corneal desiccation more readily than materials with the same overall water content but containing a larger proportion of water that interacts strongly with the polymer. The water structure [as measured by differential scanning calorimetry (DSC)] and the permeabilities of water and glucose were determined for a series of commercial hydrogel lenses. Both glucose permeability and DSC measurements are sensitive indicators of water structure and able to distinguish between various materials. To illustrate the potential of our model, the results of a short-term clinical study are presented. Lower levels of staining were noted for a material with a lower glucose permeability and a larger amount of water melting below 0 degrees C than for a control lens, even though both materials were similar in water content and water permeability. Further clinical studies are needed to validate this model.

Biocompatible Materials↗
PubMed1993

Effects of salinity on chloride cells and Na+, K(+)-ATPase activity in the teleost Gillichthys mirabilis.

1. Longjawed mudsuckers, Gillichthys mirabilis, in 30 ppt seawater (SW) were transferred to 1.5, 30 and 60 ppt SW. 2. In the first 1-3 days after transfer, plasma chloride level and plasma osmolarity rose in the 60 ppt SW fish, and decreased in the 1.5 ppt SW fish. 3. By day 21, however, plasma chloride and osmolarity were at or near the levels seen in the controls (30 ppt). 4. Branchial and jawskin Na+, K(+)-ATPase activities were high in all salinities, and did not differ significantly among treatments. 5. The vital fluorescent stains DASPEI and anthroylouabain were used to detect mitochondria and Na+, K(+)-ATPase, respectively, in chloride cells. 6. Both stains indicated that jawskin chloride cell density did not differ among treatment groups. 7. In contrast, chloride cell size increased significantly with increasing salinity. 8. The chloride cells of fish in 60 ppt SW were noticeably angular in outline, whereas those of both the 1.5 and 30 ppt SW fish were circular. 9. The results are discussed in relation to the ion transport requirements encountered in the intertidal habitat of the mudsucker.

Animals↗
PubMed1993

Proposals for health care reform: how do we evaluate them?

The Society for Academic Emergency Medicine suggests a systematic approach to evaluating proposals for reform of the medical care system. Described are the three components of the problem--access, cost, and quality. Then, goals are proposed for health care reform. With this background, we describe the major questions that reform proposals must address and the potential impact of reform on emergency medicine. Emergency physicians must actively support health reform legislation that is in the over-all best interest or our patients and our specialty, and work with the new federal administration to evaluate proposed changes.

Cost Control↗
PubMed1993

Influence of soft contact lens design on clinical performance.

A double-masked, randomized study in four parts was conducted to evaluate the effect of varying certain soft contact lens design parameters on clinical performance. The effects of varying back optic zone radius (BOZR) (8.20 to 9.00 mm), back surface design (monocurve, bicurve, aspheric), edge thickness (0.12 to 0.24 mm), and back vertex power (+ 1.00 to -6.00 D) were investigated using test lenses manufactured in a high water content material. In each part of the study, between 20 and 35 volunteer subjects wore a range of lenses which were assessed after > 30 min settling periods. Postblink movement and lens "tightness" as assessed by the push-up test were unaffected by the variation in BOZR. Lenses of flatter BOZR centered lower and more temporally than steeper lenses. Lenses of similar back surface sagittal depth, but differing in terms of back surface design, did not center the same; the monocurve lenses decentered more than bicurve or aspheric lenses. Edge thickness had no significant effect on comfort or lens fit. Plus power lenses resulted in more postblink movement than minus lenses of similar power. The results are discussed in relation to the design and fitting of soft contact lenses.

Adolescent↗
PubMed1993

Partial characterization of Nocardia farcinica beta-lactamases.

The beta-lactamases obtained from culture supernatants and cell extracts of 26 clinical strains and 5 reference strains of Nocardia farcinica were partially characterized. The enzymes exhibited two patterns on isoelectric focusing (IEF). beta-Lactamases from the majority of the 31 strains (87%) including the 5 reference strains exhibited two major bands with pIs of 4.56 and 4.49. The remaining strains had two similar major bands but with slightly higher pIs. Culture supernatants and cell extracts exhibited identical patterns. The two sets of enzymes were functionally indistinguishable by substrate and inhibitor profiles and lack of inducibility. By disk testing, ampicillin, amoxicillin, ticarcillin, amoxicillin-clavulanic acid, and imipenem were highly synergistic with cefotaxime. The enzymes were primarily penicillinases and hydrolyzed cephalosporins at rates of < or = 12% of those for penicillins. N. farcinica beta-lactamases were susceptible to inhibition by clavulanic acid and BRL 42715, exhibiting 50% inhibitory concentrations of 0.025 to 0.045 micrograms/ml (0.12 to 0.22 microM) and 0.05 to 0.1 micrograms/ml (0.31 to 0.63 microM), respectively, less susceptible to tazobactam, and least susceptible to sulbactam, cloxacillin, and imipenem. The beta-lactamases of N. farcinica are believed to mediate penicillin resistance and may play a secondary role in extended-spectrum cephalosporin resistance. The close similarity among N. farcinica beta-lactamases and their distinct differences from beta-lactamases of other Nocardia species support the taxonomic identity of this species.

Amoxicillin↗
PubMed1993

Delayed and progressive brain injury in closed-head trauma: radiological demonstration.

The importance of delayed or secondary brain insults in the eventual outcome of closed-head trauma has been documented in experimental models. To understand this phenomenon in the clinical setting, we studied a series of head-injured patients in whom multiple cranial computed tomographic (CT) scans were obtained. Patients whose follow-up CT studies revealed new intracranial lesions or worsening, compared with admission findings, were considered to have delayed cerebral injury. One hundred forty-nine (44.5%) of 337 consecutively studied patients developed delayed brain injury. There were highly significant associations (P < 0.001) between the appearance of delayed cerebral insults and the severity of the initial brain injury, the need for cardiopulmonary resuscitation in the field, the presence of coagulopathy at admission, and subdural hematoma on the initial CT scan. In addition, delayed injury was associated (P < 0.001) with higher mortality, slowed recovery, and poorer outcome at 6 months. Delayed brain injury was not significantly associated with patient age, sex, injury mechanism, associated injury, the need for endotracheal intubation in the field, early talking, CT abnormality other than intracranial hematoma, or type of residual neurological deficits. We used multiple regression analysis to explore the relationship between severity of injury, delayed insults, and outcome. As expected, the severity of the initial brain trauma contributed significantly to neurological outcome. The presence of delayed cerebral injury makes the outcome dramatically worse for each category of initial injury severity. The relationship between initial and secondary brain injury is discussed.

Adolescent↗
PubMed1993

Flexor digitorum longus tendon transfer.

A retrospective evaluation consisting of a written survey and physical examination was completed on flexor digitorum longus tendon transfer patients. The tendon transfer is used to alleviate symptoms and address imbalance of extrinsic and intrinsic muscles. The authors present an evaluation of 110 procedures with an average follow-up period of 65.7 months (range 7 to 198 months). A literature review, discussion of a new theory as to the etiology of hammer toes, and criteria for using the procedure are included.

Follow-Up Studies↗
PubMed1993

Ankle joint dorsiflexion. Establishment of a normal range.

Various values have been proposed as the required amount of ankle joint dorsiflexion, but a normal range has not been established. The authors establish a normal range based on direct measurements and compare the standard nonweightbearing method of measuring ankle joint dorsiflexion with a weightbearing method. The normal range for ankle joint dorsiflexion was established as 0 degrees to 16.5 degrees nonweightbearing and 7.1 degrees to 34.7 degrees weightbearing. A statistically significant (p < 0.01) difference exists between the two measuring systems. In addition, the study shows poor correlation between the two measurements. This lack of correlation brings into question the clinical relevance of the standard nonweightbearing measurement.

Adolescent↗
PubMed1993

Etiology of symptomatic recurrent interdigital neuromas.

Morton's neuroma is a common disease entity of the foot that is often treated with surgical resection. A complication of neuroma resection is recurrence of symptoms as a result of the formation of an amputation neuroma. The authors offer an anatomical and biomechanical explanation for the location of symptomatic amputation neuromas. The neuromas are found on the plantar surface proximal to the condyles of the metatarsal and medial to the interspace where the nerve is resected. The theory is based on intraoperative observations during surgery for recurrent neuromas and on cadaver dissections and offers a method based on this theory to reduce the number of recurrences.

Amputation Stumps↗
PubMed1993

Transverse plantar incision for heel spur surgery. Four-year follow-up survey of 35 patients.

A transverse plantar incisional approach was used on 35 patients who underwent heel spur surgery from 1982 through 1990. Ten bilateral procedures were performed on a total of 45 feet. A medial approach was used for five of the bilateral surgeries. The average age of the patient was 47 years, and the average follow-up period was 49 months. Of the 34 plantar approach cases in which complete data were obtained, 94% showed either good or excellent results. The authors illustrate a technique using a transverse plantar incision as an alternative to the medial approach for heel spur surgery.

Calcaneus↗
PubMed1993

Rheumatoid arthritic foot. Two manifestations with case studies.

The authors review rheumatoid arthritis with focus on two pedal manifestations, rheumatoid nodules and digital deformities. The prevalence, presentation, and diagnostic features concerning these entities are discussed, and three case studies are presented.

Aged↗
PubMed1993

Single daily ceftriaxone and tobramycin in the empirical management of febrile neutropenic patients: a randomised trial.

A single-institution, randomised pilot trial was conducted to compare the clinical efficacy, microbiological efficacy and possible toxicity of empirical single daily antibiotic administration in febrile neutropenic patients with haematologic disorders (absolute neutrophil count < 1 x 10(9)/l). Upon the development of signs of sepsis, patients received either single daily dose tobramycin (5 mg/kg per day) plus ceftriaxone (2 g/day) (C + T, n = 47) or tobramycin (1.5 mg/kg, every 8 h) plus azlocillin (4 g, every 6 h) (A + T, n = 45). In addition, flucloxacillin (1-2 g, every 4 h) could be added if there was clinical suspicion of staphylococcal infection (17 in each arm). Analysis was performed for the whole group and for the subset which did not receive flucloxacillin. When evaluated at 96 h, 62% of patients randomised to C + T and 67% randomised to A + T had responded (95% confidence interval (CI) for the difference in rates, -25% to +15%). Ninety-six hour response rates for those who did not receive flucloxacillin were 73% and 78%, respectively (95% CI, -17% to +27%). Overall, 42 (89%) and 41 (91%) patients, respectively, eventually became afebrile (95% CI, -14 to 10%) and there was no evidence of altered renal function or electrolyte imbalance in patients randomised to single daily antibiotic therapy compared with the conventional (multi-daily dose) arm. Within 10 days of antibiotic commencement there was 1 death in the C + T arm and 4 deaths in the A + T arm, although overall there were 4 deaths in each arm. Our results suggest that single daily empirical antibiotic therapy with tobramycin and ceftriaxone is efficacious and is not associated with an increased incidence of renal dysfunction or electrolyte imbalance compared with conventional administration schedules of azlocillin plus tobramycin. Single daily therapy has the potential to lead to savings in nursing-staff time and materials and may well contribute to an improved quality of life for febrile neutropenic patients.

Adolescent↗