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Biomedical subjects

J Tijmes

Publications and source records attributed to J Tijmes.

3 recordsLinked to original sources
PubMed1994

Monoclonal antibody to phosphatidylserine inhibits Na+/K(+)-ATPase activity.

A monoclonal IgG, directed to phosphatidylserine (PS1G3), partially (40-50%) inhibited Na+/K(+)-ATPase activity (forward running reaction cycle) without affecting the K0.5 values for Na+,K+ and MgATP. The Hill or interaction coefficients (nH) for Na+ and K+ for this reaction were reduced from 3.0 to 1.6 and from 1.6 to 0.8, respectively. The K(+)-stimulated p-nitrophenylphosphatase activity (p-NPPase), which is a partial reaction sequence of the Na+/K(+)-ATPase system (but in the backward running mode), was inhibited more strongly (about 70%) due to an increase in K+/substrate antagonism. In this system K0.5 and nH values for both p-nitrophenyl phosphate (p-NPP) and K+ were increased by the mAb. At the maximally inhibitory concentration of PS1G3 the Vmax of the p-NPPase was also reduced. Partial reactions, which were inhibited by PS1G3, are: (1) the Na(+)-activated phosphorylation (non-competitive vs. Na+), (2) the Rb+ occlusion (competitive vs. Rb+). Partial reactions not harmed by PS1G3 are: (3) the K(+)-dependent dephosphorylation, (4) the K(+)-dependent E1 + K+<-->E2K transition. We conclude that PtdSer is involved in cation occlusion, possibly by forming part of the access gate.

4-Nitrophenylphosphatase↗
PubMed1979

Arthrography in acute shoulder dislocations.

Arthrography of the shoulder was performed on 50 patients with acute traumatic shoulder dislocations. The mean interval between injury and arthrogram was 2.3 days, with a median interval of one day. Anterior dislocations occurred in 96% of patients, and posterior dislocations in 4%. Initial dislocations were present in 74%, and recurrent dislocations in 26%. The most frequent abnormality identified or arthrograms was an enlarged but intact shoulder capsule (58%), most commonly seen in shoulders subject to recurrent dislocations (77%). Shoulder joint capsular tears or disruptions were seen in 48% of the patients. The next most common lesion was fracture (52%), identified on standard roentgenograms. These included Hill-Sachs lesions (28%), greater tuberosity fractures (22%), and coracoid fractures (2%). Ruptures of the rotator cuff, present in 28% of the cases (14 patients), occurred more frequently in initial dislocations (62%) than in recurrent ones (36%). The high frequency of enlarged intact shoulder capsules, even after an acute initial joint dislocation (58%), suggests that the humeral head does not routinely rupture the capsule during dislocation, but rather tears the glenoid labrum at its bony attachment and dislocates subperiosteally, dissecting a false pouch below the periosteum and under the subscapularis.

Acute Disease↗