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Biomedical subjects

M McCoy

Publications and source records attributed to M McCoy.

At least 19 recordsLinked to original sources

Skeletal muscle GLUT-4 and postexercise muscle glycogen storage in humans.

The purpose of this study was to examine the relationship between skeletal muscle GLUT-4 protein and postexercise glycogen storage in human subjects fed adequate carbohydrate. Eleven men completed 2 h of cycling, and a biopsy of the vastus lateralis was performed immediately after exercise cessation for the determination of muscle GLUT-4 protein and glycogen concentrations, glycogen synthase activity, and citrate synthase activity. The subjects ingested meals providing 2.0 g carbohydrate/kg body weight at 0, 2, and 4 h postexercise, and a second biopsy was performed 6 h postexercise. Muscle glycogen concentration increased significantly during the 6-h recovery period (glycogen immediately postexercise, 27.2 +/- 5.4 mmol/kg wet weight; glycogen storage, 52.4 +/- 2.9 mmol x kg wet weight-1 x 6 h-1; P<0.05). Glycogen storage during recovery was directly related to GLUT-4 protein (2.20 +/- 0.33 arbitrary standard units; r = 0.63; P<0.05) and inversely related to glycogen immediately postexercise (r = -0.70; P < 0.05). A direct correlation existed between glycogen storage during recovery and the activity of the I form of glycogen synthase (r = 0.60; P < 0.05). These results suggest that muscle GLUT-4 protein concentration, as well as factors relating to glucose disposal, may affect postexercise glycogen storage in humans fed adequate carbohydrate.

Adult

Know your UAPs.

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Clinical Competence

Effect of detraining on GLUT-4 protein in human skeletal muscle.

The present study was undertaken to examine the effect of 10 days of detraining levels of GLUT-4 protein expression and citrate synthase (CS) activity in the vastus lateralis of trained men. During the course of normal training, seven endurance-trained (T) men and eight age- and weight-matched active but untrained (UT) men underwent an oral glucose tolerance test (OGTT) after an overnight fast. Muscle samples were obtained from the vastus lateralis by needle biopsy for measurement of GLUT-4 protein and CS activity. The tests were repeated on six of the T subjects after 10 days of detraining (DT men). The area under the insulin response curve during OGTT was lower in T men than in DT and UT men (22.4 +/- 2.8, 32.1 +/- 5.9, and 39.9 +/- 4.7 x 10(-3) pmol.l-1.min-1, respectively; P < 0.05). There were no differences between groups in the glucose responses to OGTT. GLUT-4 protein levels and CS activity were higher in T men than in DT and UT men (GLUT-4: 4.37 +/- 0.40, 2.92 +/- 0.53, and 1.71 +/- 0.22 arbitrary standard units and CS: 47.12 +/- 4.75, 33.63 +/- 3.98, and 24.51 +/- 2.97 mumol.min-1.g-1, respectively; both P < 0.05). Muscle GLUT-4 protein content was correlated with CS activity in all three groups (r = 0.64, 0.68, and 0.96 for UT, T, and DT men, respectively). These results suggest that muscle GLUT-4 protein content and oxidative capacity undergo parallel adaptations after detraining in previously well-trained men.

Adult

Skeletal muscle GLUT-4 and glucose uptake during exercise in humans.

The present study examined the relationship between total skeletal muscle GLUT-4 protein level and glucose uptake during exercise. Eight active non-endurance-trained men cycled at 72 +/- 1% peak pulmonary oxygen consumption for 40 min, with rates of glucose appearance and disappearance (Rd) determined by utilizing a primed continuous infusion of [3-3H]glucose commencing 2 h before exercise. Muscle glycogen content and utilization, citrate synthase activity, and total GLUT-4 protein were measured on muscle biopsy samples obtained from the vastus lateralis. A direct relationship existed between preexercise muscle glycogen content and glycogen utilization during exercise (r = 0.76, P < 0.05). Citrate synthase activity and glucose Rd at the end of exercise averaged 21.9 +/- 3.0 mumol.min-1.g-1 and 27.3 +/- 2.5 mumol.kg-1.min-1, respectively. There was a direct correlation between citrate synthase activity and GLUT-4 protein (r = 0.78, P < 0.05); however, at the end of exercise, glucose Rd was inversely related to both GLUT-4 (r = -0.89, P < 0.01) and citrate synthase activity (r = -0.72, P < 0.05). Plasma insulin, which decreased during exercise, was not related to glucose Rd. In conclusion, glucose uptake during 40 min of exercise at 72% peak pulmonary oxygen consumption was inversely related to the total muscle GLUT-4 protein level. This suggests that factors other than the total GLUT-4 protein level are important in the regulation of glucose uptake during exercise.

Adult

Early decrease in GLUT4 protein levels in brown adipose tissue of New Zealand obese mice.

The aim of this study was to determine if the previously described insulin resistance in the New Zealand Obese (NZO) mouse is associated with a decrease in GLUT4 protein and if such changes occur early in the evolution of the syndrome. GLUT4 levels were measured in whole membranes isolated from a variety of tissues in 4 and 20-week-old NZO and control NZC mice by Western blotting using a specific antibody to the C terminal end of the protein. At 20 weeks of age, GLUT4 levels were lower in the NZO mice in brown and white adipose tissue, heart, diaphragm, red and white quadriceps, and red and white gastrocnemius, but not in soleus muscle. At 4 weeks of age, GLUT4 levels were 52% lower in BAT (3309 +/- 1006 vs 6951 +/- 1870 cpm P = 0.039) but were not lower in WAT, heart or red quadriceps. It is concluded that adult NZO mice have a decrease in GLUT4 levels in most insulin-sensitive tissues and that in BAT, this occurs at an early age.

Adipose Tissue

Violent patients and the prehospital provider.

STUDY OBJECTIVES: To estimate the frequency of violence directed toward prehospital providers; to identify the methods used to manage violent patients in the prehospital setting; and to identify the educational, medical, and legal issues in the prehospital management of violent patients. DESIGN: A convenient sample survey and a descriptive review of ambulance call reports from June to December 1991. SETTING: The survey was distributed to registrants at the National Association of EMS Physicians in Pittsburgh, Pennsylvania, in June 1992. Ambulance call reports were reviewed for a metropolitan county with a service population of 60,000. INTERVENTIONS: None. RESULTS: Only about 50% of survey respondents reported having protocols for the management of violent patients. Law enforcement officers provided assistant in managing violent patients for 97% of respondents, and 81% reported that a violent patient who refused transport could be arrested. Injury to prehospital providers in the past year was reported by 67% of respondents. Although 67% reported some training in the management of violent patients, only 9% had training by law enforcement officers and only 25% thought that they were trained in assessing the scene for potential violence. Ambulance call report review identified an 0.8% incidence of violent episodes. Weapons were evident in 12% of violent encounters. Transport was refused by 18% of violent patients. In 9% of violent encounters, patients were hypoglycemic. No emergency medical technician injuries were reported for the study period. CONCLUSION: The potential for injury to prehospital providers from violent patients is probably widespread, and no mechanism for identifying injuries or exposure to violent patients currently exists. All systems should have protocols for managing violent patients and for restraint application. Educational sessions for self-defense and assessment of the scene for violence may be indicated.

Adult

Potassium and ventilation during incremental exercise in trained and untrained men.

The present investigation was undertaken to examine the relationship between plasma potassium (K+) and ventilation (VE) during incremental exercise. Blood lactate (La-) was also measured, and its relationship with VE was similarly examined. Eight endurance-trained triathletes (ET) and eight active but untrained men (UT) performed an incremental cycling test to volitional fatigue. Maximal oxygen uptake (VO2max) and oxygen uptake (VO2) at lactate threshold (LT) were higher (P < 0.05) in ET (VO2max 4.60 +/- 0.10 l/min, LT 2.77 +/- 0.85 l/min) than in UT (VO2max 3.79 +/- 0.11 l/min, LT 1.94 +/- 0.60 l/min). There were significant (P < 0.05) correlations between VE and K+ (UT 0.87, ET 0.77) and between VE and La- (UT 0.88, ET 0.85). In ET compared with UT, VE was lower (P < 0.05) at 330 W, K+ was lower at 300 and 330 W, and La- was lower at all work loads > 90 W. These results suggest that K+ may make an important contribution to the regulation of ventilation during incremental exercise and that endurance training attenuates the K+ response to that exercise.

Adult

Regulation of interleukin 2 and interleukin 2 receptor gene expression in human T cells: I. Effect of Ca2+-ionophore on phorbol myristate acetate co-stimulated cells.

Human peripheral blood T lymphocytes were treated with phorbol myristate acetate (PMA), an activator of protein kinase C (PKC) activity, and with the calcium ionophore A23187. The resulting accumulation of specific mRNA for interleukin 2 (IL-2) and interleukin 2 receptor (IL-2R), as well as IL-2 secretion and membrane IL-2R expression were examined. At low concentrations (0.1 microM), A23187 synergized maximally with PMA to induce proliferation, to increase IL-2R mRNA levels and the expression of membrane IL-2R, and to produce a low but sufficient accumulation of IL-2 mRNA and IL-2 secretion. A high concentration of A23187 (1.0 microM) did not show any synergism for the accumulation of IL-2R mRNA, membrane IL-2R expression and inhibited the proliferation of PMA co-stimulated T cells. It did, however, induce maximum accumulation of IL-2 mRNA and IL-2 secretion.

Calcimycin

[Rectal shielding for a Selectron-ring applicator system (HDR- and LDR-afterloading)].

In order to decrease the morbidity rate after combined radiotherapy of the cervix carcinoma, a tungsten shield 3 and 5 mm thick for the rectum has been developed by the authors which is applied with the ring and pin applicator of the Selectron unit (LDR- and HDR-afterloading). The isodose curves were measured in a plexiglas phantom, and the radiation dose at the reference points was determined by means of a ionization dosimeter. The phantom measurements were performed with the same arrangement of sources as applied in radiotherapy. The measurements showed a dose reduction at point Rmax of 33% (HDR) and 44% (LDR) with the tungsten shield 5 mm thick.

Brachytherapy

[Simplified standardized afterloading therapy of cervical cancer using a new applicator system (modeled after the Munich method)].

In order to be able to continue to benefit from the Munich method - fixed applicator geometry - even after changing from radium therapy to low dose rate afterloading therapy, our department has developed a standardized treatment program for the ring applicator. Its prerequisites are the dose specified on the Manchester point A and the distribution of sources specified for the ring applicator. The make-up of the source flow in the ring catheter is chosen in such a way as to reduce the maximum rectal dose to more favourable levels.

Brachytherapy

[Standardized low-dose-rate afterloading therapy of cervical cancer using a ring applicator].

At our hospital, the Munich method has already proved its value in gynecologic brachytherapy. In order to use this method for the afterloading technique (LDR), too, we developed a computer program for a standardized therapy with the circular applicator. A certain arrangement of sources is indicated for all applicator sizes. So the dose prescribed (point A) as well as the treatment times and the maximum rectum doses can be given in tabular form. Furthermore, another reduction of the exposure of the rectum could be achieved by means of a certain symmetric arrangement of the sources. To our opinion, this standardized treatment scheme allows in most cases a sufficiently exact definition of the dose distribution in the pelvis minor. If necessary, a more individualized irradiation planning can be established later using CT scans.

Brachytherapy

Splenectomy in hematologic malignancy.

Fifty patients undergoing splenectomy for complications of hematologic malignancy were reviewed to define indications and results. Primary diseases included lymphoma (n = 14), chronic lymphatic leukemia (n = 13), hairy-cell leukemia (n = 12), myeloid metaplasia (n = 6), and other similar disorders (n = 5). Indications for splenectomy in these patients included cytopenia (n = 37), diagnostic laparotomy (n = 8), "small stomach" syndrome (n = 3), and abdominal pain (n = 2). Splenectomy was performed by the midline approach in 32 patients. In 40 patients, the splenic artery was ligated prior to mobilization of the spleen. The spleens averaged 1650 g; in eight patients accessory spleens were removed. Additional surgical procedures included liver biopsy (n = 30), lymph node biopsy (n = 15), and cholecystectomy (n = 3). Intraoperative blood loss averaged 750 ml. In 14 patients, drainage of the left subphrenic space was used. Splenectomy was effective in 36 of 50 patients. In seven patients, splenectomy was ineffective in correction of cytopenia. Seven mortalities were from bleeding (n = 2), pulmonary embolus (n = 2), postoperative sepsis (n = 2), and progression of primary disease (n = 1). Additional complications included reoperation for bleeding (n = 3), septic complications including pneumonia (n = 14), wound infection (n = 4), and intra-abdominal abscess (n = 2). Splenectomy for the patients with hematologic malignancy is generally effective. Meticulous hemostasis, timely administration of intraoperative platelets, surgical asepsis, and aggressive pulmonary care are essential to reduce morbidity and mortality.

Adult

Human c-Ki-ras2 proto-oncogene on chromosome 12.

A human colonic adenocarcinoma transforming gene, recently identified as a cellular homolog of the Kirsten sarcoma gene (v-ras), was used to assign the human cellular Kirsten ras2 gene to chromosome 12 by the Southern hybridization method. A single 640 base-pair Eco RI--Hind III fragment of the transforming gene, isolated by DNA transfection and molecular cloning, can detect a single Eco RI fragment (2.9 kilobase pairs) of DNA from phenotypically normal cells. The data suggest a constant chromosomal location of c-Ki-ras2.

Adenocarcinoma

A test of the role of two oncogenes in inherited predisposition to colon cancer.

Inheritance of mutationally altered oncogenes could predispose individuals to the development of specific tumors and account for familial tumor phenotypes. Using adjacent DNA sequence polymorphisms as genetic markers, we have examined two oncogenes, the Kirsten ras2, isolated from a human colon cancer cell line, and the Harvey ras1, isolated from a human bladder cancer cell line, for their role in the genetic etiology of inherited colon cancer in Gardner syndrome. Both oncogene loci have been shown to be unlinked to the Gardner syndrome locus and are, therefore, eliminated as candidates for the Gardner syndrome gene.

Base Sequence

Duodenal injury. Analysis of common misconceptions in diagnosis and treatment.

Seventy-five consecutive patients who sustained injuries to the duodenum were admitted to our hospital over a nine-year period. Nineteen blunt injuries and 56 penetrating injuries were encountered. Blunt injuries were usually the result of motor vehicle accidents and steering wheel impact was frequently implicated. Penetrating injuries most commonly followed gunshot wounds, particularly those where the bullet tract travelled transversely across the peritoneal cavity. Seventy-nine per cent of the patients had two or more associated intra-abdominal organ injuries with other intestinal injuries, biliary tract injuries, and pancreatic injuries predominating. Forty-seven per cent of the patients were admitted in shock. Following blunt injury, diagnostic delay was encountered in two patients. Adjuncts to diagnosis such as abdominal roentgenograms, serum amylase levels, and contrast gastroduodenography, were not helpful. Peritoneal lavage, however, was valuable in patients with equivocal physical findings. Intraoperative diagnosis was also challenging. Complete mobilization of the structures surrounding the duodenum to provide exposure of the entire duodenum was necessary. Six injuries that initially appeared trivial would have been missed had this procedure not been followed. Suture closure was the most common reparative technique used. Tube decompression of the duodenum was a valuable addition. No suture line dehiscences were encountered in ten patients so treated. Overall mortality in patients surviving more than 24 hours was 12%.

Abdominal Injuries