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Biomedical subjects

L Wright

Publications and source records attributed to L Wright.

At least 127 records · Page 7Linked to original sources
PubMed1982

Distance and movement time effects on the timing of agonist and antagonist muscles: a test of the impulse-timing theory.

The experiment examined the effects of movement time (MT) and distance on the timing at electromyographic (EMG) activity from an agonist and antagonist muscle during rapid, discrete elbow movements in the horizontal plane. According to impulse-timing theory (Wallace, 1981) MT, not distance moved, should have a pronounced effect on the timing of EMG activity (duration of initial agonist and antagonist burst and time to onset of initial antagonist burst). The levels of MT were 100 and 160 msec and the levels of distance were 27 degrees and 45 degrees of elbow flexion. In general support of impulse-timing theory, the results of the three EMG timing measures showed that MT had a more pronounced effect on these measures than distance. In addition, the timing of EMG activity in relation to total MT remained fairly consistent across the four MT-distance conditions.

Journal Article↗
PubMed1982

Ten years portal hypertensive surgery at Emory. Results and new perspectives.

Five hundred four Shunt procedures have been done at Emory University Hospitals between 1971 and 1981 to decompress bleeding esophageal varices. This paper reviews how far the experiences of a prospective randomized study (55 patients) of distal splenorenal shunts against total shunts is supported by the nonrandomized experience (449 patients), and outlines our current methods of management dictated by this experience. The overall operative mortality for 348 selective shunts is 4.1% and for 156 nonselective shunts, 14.1%. The five-year survival following Selective shunt is 59%, and following nonselective shunt is 49%: more than half the selective shunt patients are alive, in contrast to the median survival of 44.5 months for patients having nonselective shunts. Following Selective shunt, the survival in nonalcoholic patients is significantly better than the median survival of alcoholic patients of 57 months. Encephalopathy, reported at three years after surgery in the randomized patients was significantly (p < 0.001) lower after selective shunt (12%) compared to nonselective shunt (52%): in the same population at seven years, all patients with patent nonselective shunts have clinical or subclinical encephalopathy, but only 30% of the selective shunt patients have subclinical encephalopathy. Shunt patency, immediately after surgery, is 93% following selective shunt, with only two documented late thromboses: nine of nine patients, at a mean of seven years, retain patency in the randomized study. Shunt occlusion increases with time after interposition nonselective shunts: seven of 13 are occluded at a mean follow-up of seven years in the randomized study. Portal venous perfusion is retained in 93% of patients seven to ten days after selective shunt, but in no patient with a patent nonselective shunt. Late portal perfusion is maintained in nine of the eleven patients in the randomized group studied at a mean of seven years after selective shunt. Restoration of portal perfusion has led to clearing of encephalopathy and improvement in hepatic function in six patients. The following conclusions are made: (1) selective shunts can be done with low operative mortality, and long-term patency with excellent control of bleeding; (2) hepatic portal venous perfusion has been maintained after selective shunt for ten years, and this is vital for preventing encephalopathy and maintaining hepatic function; (3) long-term survival after selective shunt is better than any reported series for nonselective shunt; and (4) selective shunts are the operative procedure of choice for variceal decompression and nonselective shunts should rarely be performed for elective decompression.

Analysis of Variance↗
PubMed1982

The incidence and natural history of thrombus in the portal vein following distal splenorenal shunt.

The incidence of thrombus formation in the portal vein following distal splenorenal shunt was 4% occlusive and 14% nonocclusive from 1974 to 1977, and 6% occlusive and 22% nonocclusive in 1980. The increased incidence was probably due to more aggressive ligation of collaterals on the portal vein. Ten patients with this complication were evaluated prospectively with clinical and biochemical parameters, angiography, and nutrient hepatic perfusion. In this group, one thrombus was occlusive immediately after operation, and nine were nonocclusive: eight of the latter resolved by six months, but one progressed to total thrombosis. There were no demonstrable adverse clinical or biochemical sequelae. Angiography showed continuing portal perfusion in the face of nonocclusive thrombus, but at six months there was increased collateral formation and significant (p less than 0.05) reduction in portal vein diameter, from 20 +/- 4 mm to 14 +/- 5 mm. Nutrient hepatic perfusion at six months, 896 +/- 257 ml/min, was not significantly different from that seen prior to operation, 848 +/- 92 ml/min. It is concluded that the natural history of nonocclusive portal vein thrombus after distal splenorenal shunt is resolution, and management should be expectant.

Adult↗
PubMed1982

Coordinated system for comprehensive newborn metabolic screening.

In September 1978 phenylketonuria (PKU) screening in the state of Georgia was expanded to include testing for five additional metabolic disorders. Our goal was to begin therapy within the first three weeks of an infant's life. During the first 22 months, 167,458 specimens were received; 151,250 from infants less than or equal to 1 week of age. During this period 157,893 live births were reported. More than 90% of 2,299 infants with abnormal screening results were retested. The number of cases and incidence of each disease detected were hyperphenylalaninemia, five (1/31,579); maple syrup urine disease, 0 (0/151,250); homocystinuria, one (1/151,250); galactosemia, two (1/63,352); transient tyrosinemia (greater than or equal to 12 mg/dl), 50 (1/3,158); primary congenital hypothyroidism, 17 (1/7,453); and thyroid binding globulin deficiency, ten (1/12,670). For eight children with either hyperphenylalaninemia, homocystinuria, or galactosemia, the average time for retrieval between the initial abnormal screening result ad the first follow-up test was 6.2 days (range three to ten days). Therapy was started by 9.9 days of age (range seven to 17). For the 17 children with congenital hypothyroidism, the retrieval time was 11.6 days (range three to 27) and treatment began by 21.3 days of age (range ten to 69 days).

Academic Medical Centers↗
PubMed1981

Cell survival in chick embryo ciliary ganglion is reduced by chronic ganglionic blockade.

Changes in the activities of enzymes involved in the synthesis or degradation of transmitters has been used as an index of maturation in autonomic neurons. In some cases, a reduction in enzyme activity during normal development may reflect decreased cell survival rather than, or in addition to, changes in the rate of development. Similarly, changes in enzyme activity following experimental manipulation during development may also reflect cell loss. In the ciliary ganglion, biochemical indexes of development are altered after denervation, and after treatment with a ganglionic blocker, chlorisondamine. Surgical removal of afferents to the ciliary ganglion in the early chick embryo results in a virtually complete loss of ganglion cells. Chiappinelli et al. have reported that choline acetyltransferase (ChAT) is reduced in chick iris and ciliary ganglion after chronic treatment with chlorisondamine (on days 5, 8, 10 and 13 of incubation). This suggests that the development of transmitter enzymes may be regulated via interaction at the presynaptic site. Since they also report that chlorisondamine treatment reduced ganglionic dry weight, which could reflect a loss of cells, it may be that the same synaptic interaction governs cell survival as well as enzyme maturation. The present study provides evidence that treatment with chlorisondamine does, in fact, reduce cell survival in the ciliary ganglion.

Afferent Pathways↗
PubMed1978

In-house staff designs energy-saving system.

With a relatively small amount of money and a lot of ingenuity, an innovative engineering team developed a successful pilot program that resulted in substantial energy and dollar savings. Using commercially available component parts, the team designed a preventive maintenance and energy-saving microprocessor system that is especially geared toward the hospital setting.

California↗
PubMed1978

Interactive effects of parity and early pup stress on the open field behavior of laboratory rats.

Pups of primiparous and multiparous Sprague Dawley rats received 0-, 2-, or 5-min cold stress on Days 2-6 postpartun. Stressed offspring of primiparous mothers had shorter latencies to move in an open field than did control offspring of primiparous mothers. However, stressed offspring of multiparous mothers had longer latencies than did the controls. The results suggest differences in maternal responsiveness immediately following return of stressed pups to the nest.

Animals↗
PubMed1978

Antigenic relationships between the typhus and spotted fever groups of rickettsiae.

Paired sera from cases of epidemic typhus in Ethiopia and from probable cases of Rocky Mountain spotted fever (RMSF) in the United States were examined by microagglutination (MA) and microimmunofluorescence (micro-IF) tests for antibodies against Rickettsia prowazekii, Rickettsia typhi, Rickettsia canada, Rickettsia rickettsii, Rickettsia conorii and Ricksettsia akari. IgG and IgM antibodies against the various rickettsiae were titrated with specific fluorescein-conjugated anti-IgG and anti-IgM sera. Purified, particulate rickettsial antigens were employed in all tests. A majority of patients acutely ill with epidemic typhus produced both IgG and IgM antibodies against R. prowazekii, R. typhi and R. canada. Concurrently they produced IgG (but seldom IgM) antibodies against members of the spotted fever group. In contrast, patients ill with probably spotted fever, while producing IgG and IgM antibodies against R. rickettsii, R. conorii and R. akari, also produced both IgG and IgM antibodies with about equal frequency against members of the typhus group. It was concluded that a relatively broad antigenic relationship exists between rickettsiae of the typhus and spotted fever groups.

Agglutination Tests↗
PubMed1977

Effect of handling on maternal behavior following return of pups to the nest.

Handling rat pups during the 1st week after birth altered adult behavior in the open-field, whereas simply spearating the pups from their mothers during the same period produced differences in body weight at weaning. Observations of mother-infant interaction following pup treatment yielded different patterns of maternal behavior. Moreover, pups receiving early treatment were more active as adults in a novel environment and had a greater body weight at weaning. The quality of maternal care and the immediate effects of infantile stimulation on the mother-infant relation should be considered in specifying a mediating mechanism for the effects of early experience.

Age Factors↗