Accuracy of the functional method of hip joint center location: effects of limited motion and varied implementation.

Accurate location of the hip joint center is essential for computation of hip kinematics and kinetics as well as for determination of the moment arms of muscles crossing the hip. The functional method of hip joint center location involves fitting a pelvis-fixed sphere to the path traced by a thigh-fixed point while a subject performs hip motions; the center of this sphere is the hip joint center. The aim of the present study was to evaluate the potential accuracy of the functional method and the dependence of its accuracy on variations in its implementation and the amount of available hip motion. The motions of a mechanical linkage were studied to isolate the factors of interest, removing errors due to skin movement and the palpation of bony landmarks that are always present in human studies. It was found that reducing the range of hip motion from 30 degrees to 15 degrees did significantly increase hip joint center location errors, but that restricting motion to a single plane did not. The magnitudes of these errors, however, even in the least accurate cases, were smaller than those previously reported for either the functional method or other methods based on pelvis measurements of living subjects and cadaver specimens. Neither increasing the number of motion data observations nor analyzing the motion of a single thigh marker (rather than the centroid of multiple markers) was found to significantly increase error. The results of this study (1) imply that the limited range of motion that is often evident in subjects with hip pathology does not preclude accurate determination of the hip joint center when the functional method is used; and (2) provide guidelines for the use of the functional method in human subjects.     

Differences in Fine Structures between Normal and RNA-induced Drosophila Pole Cells

Fine structures were compared between normal pole cells and those induced in embryos that had been uv-irradiated and then injected with intact polar plasm or with poly(A)⁺RNA extracted from cleavage embryos. Nuclei in nomal pole cells were spherical. In contrast, those in the induced pole cells were deformed to variable extents depending on materials injected with. Polar granules were smaller in pole cells induced by injection of poly(A)⁺RNA than in normal pole cells. The size of polar granules in polar-plasm-induced pole cells was intermediate between those in poly(A)⁺RNA-induced and normal pole cells. Small polar granules were observed in posterior cells of embryos uv-irradiated, nevertheless those cells were columnar and with identical morphology to somatic cells. Nuclear bodies showed a similar tendency in size differences as observed in polar granules in three types of pole cells observed.     

Effects of pancreastatin on insulin and pancreatic polypeptide secretion in the dog

Porcine pancreastatin (1.19 nmol) was administered into the peripheral vein (i.v.) or the third cerebral ventricle (i.t.v.) of dogs and its effect on the secretion of insulin and pancreatic polypeptide (PP) studied. Neither means of administration had any effect on basal and glucose-induced insulin or PP secretion. However, i.v. pancreastatin did inhibit the i.v. CCK-8-induced insulin but not PP release. Pancreastatin may thus play a role in the regulation of insulin secretion in the canine pancreas.     

Omega-hydroxylation of prostaglandin E1 in the isolated perfused lungs of pregnant rabbits

Cytochrome P450PG omega is induced in the rabbit lung in a gestational age-dependent manner and hydroxylates certain eicosanoids at their terminal, or omega (omega), carbon. This enzyme has been isolated from microsomal fractions and its activity has been characterized (Williams, D.E., et al., J. Biol. Chem. 259; 14600-14608, 1984). The experiments presented here examine the omega-hydroxylation activity of the intact lung during presentation of an eicosanoid substrate, prostaglandin E1 (PGE1), to the lung vasculature. Isolated, perfused lungs from three pregnant and four nonpregnant rabbits were injected with [3H]-PGE1. One-second fractions were collected from the perfusion effluent and were analyzed for metabolism of PGE1. Lungs isolated from pregnant rabbits metabolized PGE1 mainly to two polar derivatives, 20-hydroxy-PGE1 and 13,14-dihydro-15-keto-20-hydroxy-PGE1, whereas lungs from nonpregnant rabbits yielded mainly a relatively nonpolar metabolite, 13,14-dihydro-15-keto-PGE1. These metabolites were identified by coelution with standards that were generated enzymatically in vitro and whose structures were confirmed by gas chromatography/mass spectrometry (GC/MS).     

Oxygen uptake rate of immobilized growing hybridoma cells

Summary The specific oxygen uptake rate of hybridoma cells immobilized in calcium alginate gel particles was measured, and the observed data was compared with those of non-immobilized cells. The uptake rate of the immobilized cells coincided with that of the non-immobilized hybridoma cells just after immobilization, but increased with cell growth. On the other hand, the cellular glucose consumption rate decreased slightly during the experiments. The increased oxygen uptake rate by immobilized cells was closely related to the formation of cell colonies in the gel particles.     

Formation of wheat protein bodies: Involvement of the Golgi apparatus in gliadin transport

Developing wheat (Triticum aestivum L.) endosperm was examined using ultrathin sections prepared from tissues harvested at 5, 9, 16 and 25 d after flowering. Protein bodies were evident by 9 d and displayed a variety of membranous structures and inclusions. The Golgi apparatus was a prominent organelle at all stages, and by 9 d was associated with small electron-dense inclusions. By immunocytochemical techniques, gliadin (wheat prolamine) was localized within these vesicles and in homogeneous regions of protein bodies, but not in the lumen of the rough endoplasmic reticulum. The protein bodies appear to enlarge by fusion of smaller protein bodies resulting in larger, irregular-shaped organelles. The affinity of the Golgi-derived vesicles for gliadin-specific probes during the period of maximal storage-protein synthesis and deposition indicates that this organelle includes the bulk, if not all, of the gliadin produced. The involvement of the Golgi apparatus in the packaging of gliadins into protein bodies indicates a pathway which differs from the mode of prolamine deposition in other cereals such as maize, rice and sorghum, and resembles the mechanism employed for the storage of rice glutelin and legume globulins.Abbreviations ER endoplasmic reticulum - IgG immunoglobulin G - DAF days after flowering     

Effects of CCK antagonists on CCK-induced suppression of locomotor activity in mice.

Sulfated cholecystokinin octapeptide (CCK-8) was administered either intraperitoneally or into the cerebral ventricle of fully conscious mice, and locomotor activity was quantified. CCK-8 administered by either route suppressed locomotor activity. Subcutaneously administered selective CCK-A receptor antagonist, L-364,718 (1 mg/kg), reversed the inhibitory effect of centrally as well as peripherally administered CCK-8, but the selective CCK-B receptor antagonist, L-365,260 (1 mg/kg), did not. These results demonstrate that centrally as well as peripherally administered CCK-8 suppresses locomotor activity in mice through an interaction with CCK-A, but not CCK-B, receptors.     

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area

To assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (31P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSAmax) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J.cm-2 CSAmax for 1 min and an increment of 1 J.cm-2 CSAmax every minute to the point of muscle exhaustion. A series of measurements of 31P-MRS were performed every minute. The CSAmax was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm2, P less than 0.05]. The absolute maximal exercise intensity (J.min-1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J.min-1.cm-2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5'-diphosphate to drive adenosine 5'-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J.min-1.cm-2).(ABSTRACT TRUNCATED AT 250 WORDS)     

Nucleotide and primary sequence of a major rice prolamine

A recombinant cDNA clone encoding a major rice seed storage prolamine was isolated by antibody screening of a cDNA lambda gt 11 library. This clone contained a single open reading frame encoding a putative rice prolamine precursor (Mr 17,300). In contrast to other cereal prolamines, the primary sequence of the rice prolamine was devoid of any major tandem repetitive sequences, a feature prevalent in all cereal prolamines studied to date. No significant homology was detected between the rice prolamine and other cereal prolamines, indicating that the rice gene evolved from unique ancestral DNA segments.     

Characterization of an endogenous inhibitor of lung 15-hydroxyprostaglandin dehydrogenase

An endogenous inhibitor of the NAD+-dependent 15-hydroxyprostaglandin dehydrogenase was isolated from the 105,000 X g supernatant fraction of lungs of pregnant rabbits following DEAE chromatography. The material was heat stable and was resistant to pronase treatment. The inhibitor contained a mixture of saturated and mono-unsaturated fatty acids and cholesterol with palmitate and oleate representing the major fatty acids in the inhibitory factor. The factor inhibited prostaglandin dehydrogenase activity but had only minor effects on the activity of NAD+-dependent alcohol and lactate dehydrogenases or the NADP+-dependent isocitrate dehydrogenase. In an attempt to develop a greater understanding of the inhibitory action of fatty acids on prostaglandin dehydrogenase activity, a variety of standard fatty acids were examined for their ability to decrease enzymic activity. Oleate and palmitate inhibited enzymic activity by 70% at 10 microM, whereas arachidonate and myristate were only 30% inhibitory at this concentration. A comparison among the 18-carbon-containing fatty acids demonstrated that oleate was more potent than linoleate and linolenate in inhibiting prostaglandin dehydrogenase activity. The coenzyme A derivatives of oleate, linoleate and linolenate were less inhibitory than the free fatty acids.