Biomedical subjects

G W Lange

Publications and source records attributed to G W Lange.

17 recordsLinked to original sources

PubMed1998

Quantification of elastic resistance knee rehabilitation exercises.

Elastic resistance exercises are frequently used for knee rehabilitation following injury and/or surgery. The evidence supporting this mode of rehabilitation is primarily anecdotal, and no biomechanical assessment of elastic resistance exercises has been previously published. The purpose of this project was to quantify muscle activation levels, knee joint angles, and applied force during five rehabilitation exercises utilizing an elastic resistance device. Twelve subjects with no previous knee injury performed double knee dip, hamstring pull, leg press, single knee dip, and side-to-side jump exercises while sagittal plane kinematics, applied force from the elastic resistance device, and electromyographic activity of eight lower extremity muscles were collected. The muscle activation patterns suggest a progressive continuum of rehabilitation exercises that can be applied to nonoperative injuries as well as anterior cruciate ligament reconstructions.

Adult↗

PubMed1997

Muscle activity in wedge, parallel, and giant slalom skiing.

Muscle activity patterns of six alpine skiers were compared during nine runs each of wedge (W), short radius parallel (P), and giant slalom (GS) turns. Bipolar surface electrodes were placed over 12 muscles on the right side of the body: anterior tibialis, medial gastrocnemius, vastus medialis, vastus lateralis, rectus femoris, medial hamstrings, biceps femoris, gluteus maximus, adductors, rectus abdominis, external obliques, and erector spinae. Repeated measures ANOVA was used to test for differences in average and peak EMG amplitudes between W, P, and GS (P < 0.1). Average amplitude was significantly different between all turning styles (W < P < GS) for four muscles (vastus lateralis, medial hamstrings, biceps femoris, and external obliques) and significantly less for W versus P or GS for four muscles (anterior tibialis, vastus medialis, rectus femoris, and rectus abdominis). The gluteus maximus was the only muscle that had significantly greater activity in W than P. Average amplitude was greater than 50% MVC for the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions; and for the anterior tibialis, medial hamstrings, and rectus femoris in GS and P; and for the medial gastrocnemius and erector spinae in GS. Peak amplitude was greater than 150% maximal voluntary contraction (MVC) for the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions, and for the medial gastrocnemius, rectus femoris, and erector spinae in GS. This research indicates that with the exception of the gluteus maximus, greater muscle activity is required in GS followed by P and W turns.

Adult↗

PubMed1996

Electromyographic and kinematic analysis of graded treadmill walking and the implications for knee rehabilitation.

Muscle activity, joints, angles, and heart rate during uphill walking were compared for application in knee rehabilitation. The objectives of this study were to quantify muscle activation levels at different treadmill grades and to determine the grade(s) at which knee range of motion would not further compromise the joint. Average and peak electromyographic activity of the quadriceps (vastus medialis oblique and vastus lateralis) and hamstrings (biceps femoris and medial hamstrings (semimembranosus/semitendinosus)] was recorded during walking at 0, 12, and 24% grade. Six subjects (age = 28.5 +/- 3.7 years, stature = 1.79 +/- .05 m, and mass = 74.7 +/- 7.9 kg) walked at self-selected speeds at each grade while ankle, knee and hip angles, heart rate, and electromyographic activity (surface electrodes) were recorded. Maximum voluntary contractions provided a relative reference for the electromyographic activity during walking. Average and peak electromyographic activity increased significantly across grades for the vastus medialis oblique (125 and 154%), vastus lateralis (109 and 139%), and biceps femoris (53 and 46%), but remained similar for the medial hamstrings. Maximum knee flexion at heel strike increased significantly with grade. Despite decreased self-selected speeds with increasing grade, there were significant increases in heart rate across grades. The results of this study provide a basic understanding of the quadriceps and hamstrings activity levels, lower extremity joint range of motion, and cardiovascular requirements of graded treadmill walking in normal subjects. The results also suggest that a grade just greater than 12% may be most beneficial for knee rehabilitation to minimize patellofemoral discomfort or potential strain on the anterior cruciate ligament. The benefits achieved through this functional activity encourage its implementation in rehabilitation and provide a basis for comparison with injured patients.

Adult↗

PubMed1995

Muscle activity in slalom and giant slalom skiing.

The purpose of this study was to document and compare the muscular activity patterns observed in seven competitive racers during slalom (SL) and giant slalom (GS) skiing using quantitative parameters of EMG and qualitative video recordings. Twelve muscles of the leg and trunk were monitored using surface electrodes and telemetry. EMG activity was related to phases of movement determined from the video. SL was partitioned into two phases (initiation and turning) and a third phase (completion) was distinguished for GS. The majority of muscles were active at a moderate to high level for the whole turn, with average amplitudes (AA) between 58% and 112% maximum voluntary contraction. Large peak amplitudes (PA) were attributed to the substantial components of centrifugal and gravitational force that the skier must resist in the latter part of the turn. The similarity in muscle activity between SL and GS was surprising. The only significant differences were increases of 11.8% in AA for the AT in SL and 8.8% in PA for the EO in GS. There was ample evidence of co-contraction, suggesting a quasistatic component to skiing.

Abdominal Muscles↗

PubMed1994

Heterogeneity of plasma tissue factor pathway inhibitor.

Much of tissue factor pathway inhibitor (TFPI) in plasma is bound to lipoproteins. The major form of TFPI associated with low density lipoproteins (LDL) is 34 kDa, whereas that associated with high density lipoproteins (HDL) is 41 kDa and appears in part to represent a mixed disulphide complex between TFPI and apolipoprotein AII. The native and recombinant TFPI produced by mammalian cells in tissue culture and the TFPI released by heparin in vivo, however, are 34 kDa. Western blotting with antibodies raised against specific TFPI peptides and cation exchange chromatography under denaturing conditions of partially purified plasma TFPI suggest that only a fraction of TFPI circulating in plasma is in the form of the full length molecule, the remainder consisting of variably carboxyl-terminal truncated forms. Electrospray mass spectrometry of the isolated 34 kDa form of plasma TFPI, which predominantly circulates bound to LDL, confirms that it lacks a substantial portion of the carboxyl-terminus including at least a portion of the third Kunitz-type domain.

Amino Acid Sequence↗

PubMed1993

Identification and oligosaccharide structure analysis of rhodopsin glycoforms containing galactose and sialic acid.

The N-linked oligosaccharides of frog (Rana pipiens) rhodopsin were analysed by sequential exoglycosidase digestion and gel filtration chromatography, following reductive tritiation. In addition, selected tryptic glycopeptides obtained from frog retinal rod outer segment membranes were examined by electrospray mass spectrometry (ES-MS), fast atom bombardment mass spectrometry (FAB-MS), amino acid sequence and composition analysis, and carbohydrate composition analysis. The amino acid sequence data demonstrated that the glycopeptides were derived from rhodopsin and confirmed the presence of two N-glycosylation sites, at residues Asn2 and Asn15. The predominant glycan (approximately 60% of total) had the structure GlcNAc beta 1-2Man alpha 1-3(Man alpha 1-6) Man beta 1-4GlcNAc beta 1-4GlcNAc-(Asn), with the remaining structures containing 1-3 additional hexose residues, as reported previously for bovine rhodopsin. Unlike bovine rhodopsin, however, a sizable fraction of the total glycans of frog rhodopsin also contained sialic acid (NeuAc), with the sialylated oligosaccharides being present exclusively at the Asn2 site. FAB-MS analysis of oligosaccharides released from the Asn2 site gave, among other signals, an abundant quasimolecular ion corresponding to a glycan of composition NeuAc1Hex6HexNAc3 (where Hex is hexose and HexNAc is N-acetylhexosamine), consistent with a hybrid structure. The potential biological implications of these results are discussed in the context of rod outer segment membrane renewal.

Amino Acid Sequence↗

PubMed1992

Comparison of recombinant tissue factor pathway inhibitors expressed in human SK hepatoma, mouse C127, baby hamster kidney, and Chinese hamster ovary cells.

Recombinant tissue factor pathway inhibitor (rTFPI) has been expressed in four mammalian expression systems using human SK hepatoma, mouse C127, baby hamster kidney (BHK), and Chinese hamster ovary (CHO) cells as hosts. On sodium dodecyl sulfate polyacrylamide gel electrophoresis, the immunoaffinity purified rTFPIs all show broad bands and the mean molecular weight of SK hepatoma and C127 rTFPIs (M(r) approximately 38,000) appear larger than those of BHK and CHO rTFPIs (M(r) approximately 35,000). All these proteins inhibit factor Xa and appear to bind factor Xa with 1:1 stoichiometry. The ability of these proteins to inhibit tissue factor-induced coagulation in plasma was examined using a prothrombin time assay. The relative activities of SK rTFPI:C127 rTFPI:BHK rTFPI:CHO rTFPI were found to be 28:15:2.1:1. By Western blot using specific antisera against the amino- and carboxy-termini of TFPI as probes, it is found that all the immunoaffinity purified rTFPIs possess approximately equal amounts of the amino terminus, but the C127 and BHK rTFPIs are deficient in carboxy terminus and the CHO rTFPI is essentially devoid of this region of the protein. Mono S chromatography allowed separation of the full-length and the truncated molecules with high and low anticoagulant activities, respectively. The above results suggest that proteolysis of the carboxy terminus of TFPI occurs to different extent when TFPI is expressed in different cells and that the carboxy terminal region of the TFPI molecule is important for the inhibition of tissue factor-induced coagulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Purification and characterization of pituitary bovine somatotropin.

Bovine somatotropin (bST) has been isolated from pituitary glands and compared in a variety of chemical analyses and bioassays with somatotropin derived from recombinant Escherichia coli. Comparison of pituitary extracts and purified bST by Western blot analysis of two-dimensional gels suggested that the immunoreactive somatotropin species present in the extract were also present in the purified material, with no significant losses or degradation as a result of the purification method. NH2-terminal sequence analysis indicated the presence of equal quantities of Ala-Phe-Pro-Ala-Met-Ser-Leu-Ser- and Phe-Pro-Ala-Met-Ser-Leu-Ser- sequences. The Met-Ser-Leu-Ser-NH2-terminal sequence, a degradation product observed in NIH standard lots, was not detected. Assay of bioactivity in a bovine liver receptor-binding assay and in a female rat growth assay showed pituitary bST and recombinant methionyl-bovine somatotropin to be equipotent. Tryptic maps and sequence analysis of pituitary-derived somatotropin suggest the presence of isoaspartate derivatization at Asp128.

Amino Acid Sequence↗

PubMed1980

Distribution of DNA polymerase Cm in normal and malignant human tissues.

The distribution in human tissues has been determined of the new DNA polymerase activity designated DNA polymerase Cm, first isolated from the human melanoma cell line A-375. Tissue samples were fractionated by ion exchange chromatography on diethylaminoethyl cellulose and phosphocellulose and by affinity chromatography on poly(2'-O-methylcytidylate)-Sepharose. DNA polymerase activity was monitored with poly(2'-O-methylcytidylate) . oligodeoxyguanylate and poly(adenylate) . oligodeoxyribothymidylate, the most specific and most sensitive template primers, respectively, for DNA polymerase Cm. Tissues were scored as to presence or absence of detectable DNA polymerase Cm activity as well as to their validity for scoring dependent on content of total DNA polymerase activity. On this basis, seven of 14 malignant and none of 11 normal or embryonic tissues were found to contain detectable levels of DNA polymerase Cm.

DNA-Directed DNA Polymerase↗

PubMed1970

Effect of speed of muscle contraction on physiological tremor in normal subjects and in patients with thyrotoxicosis and myxoedema.

The speed of the ankle jerk and physiological finger tremor in patients with thyrotoxicosis and myxoedema have been compared with those in age-matched control subjects. Tremor amplitude depends on the speed of muscle contraction; the faster muscle contracts the greater is the amplitude of tremor, and vice versa. The frequency of the dominant tremor peak is not affected by the speed of contraction but its size increases as muscle contracts faster. Muscle dynamics is clearly one of many factors influencing physiological tremor but is not responsible for the dominant frequency of tremor at round 9 c/sec.

Ankle↗

PubMed1969