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Biomedical subjects

S Katz

Publications and source records attributed to S Katz.

At least 397 records · Page 22Linked to original sources
PubMed1981

Splenic pseudocyst associated with hypersplenism.

A patient with hypersplenism, who was found to have a splenic pseudocyst containing an organized hematoma, is described. There are only two patients with splenic pseudocyst and hypersplenism and an additional two patients with splenic cysts and hypersplenism reported in the world literature. The hypersplenism associated with splenic cysts and pseudocysts is explained on the basis of an expansion of the plasma volume and the total blood volume, an increased destruction of red blood cells and a pooling of blood in the enlarged spleen. The combined use of ultrasonography and computerized tomography has increased the accuracy of noninvasive diagnosis and made more invasive examinations unnecessary. When the ultrasound is technically unsuccessful or when it shows a mixed echo pattern, one should resort to computerized tomography with which it is possible, almost invariably, to differentiate between cysts and neoplasms.

Adult↗
PubMed1981

Six-year experience with bovine arterial graft for hemodialysis.

During the last six years 29 bovine arterial grafts were implanted in 21 patients. A total of 186 angioaccesses had been performed on these patients prior to the insertion of bovine graft. Nineteen grafts (65.5%) are still patent with a mean patency time of 43 months. Ten grafts (34.5%) failed, the main cause of failure being infection. The cumulative patency of failed grafts was 46 months.

Adolescent↗
PubMed1981

Serial radionuclide liver imaging in Budd-Chiari syndrome.

Budd-Chiari syndrome or hepatic vein occlusion may be related to oral contraceptive medication. A patient is presented in whom radionuclide liver imaging contributed to the diagnosis of the syndrome and to the management of the patient.

Adult↗
PubMed1981

Giant pseudopolyps in Crohn's colitis. A nonoperative approach.

Six patients with Crohn's disease had colonic intraluminal multilobulated masses detected on barium enema. Four had Crohn's colitis and two ileocolitis. The mean duration of disease was four and eight tenths years. Three patients underwent surgery and three had colonoscopy with multiple biopsies and cytology. Pseudopolypoid inflammatory tissue was found in each case. One patient died after a prolonged postoperative course due to sepsis and abscess formation. No surgery was performed in three patients and follow-up colonoscopic examinations at four and a half years revealed no change in these findings. The presence of an intraluminal colonic mass in Crohn's colitis may mimic a neoplasm. If surveillance with x-ray, endoscopic biopsies and cytology reveals pseudopolypoid inflammatory tissue then surgery is not mandatory. Pseudopolypoid inflammatory tissue has never been associated with carcinoma.

Adult↗
PubMed1980

Characterization of calmodulin effects on calcium transport in cardiac microsomes enriched in sarcoplasmic reticulum.

Calmodulin prepared from red cell hemolysates was found to significantly increase Ca2+ uptake into cardiac microsomal preparations enriched in sarcoplasic reticulum in a dose-dependent manner. The stimulation of calcium uptake by calmodulin was additive to that stimulation produced by maximal stimulatory concentrations of adenosine cyclic 3',5'-phosphate (cAMP) dependent protein kinase and cAMP, indicating separate mechanisms of action and potentially different modulatory roles for these two systems in the control of calcium transport. K+ significantly decreased calmodulin stimulation of calcium uptake, while in the absence of calmodulin, K+ increased Ca2+ uptake. In the absence of K+, calmodulin increased Ca2+ uptake to levels observed at maximal K+ concentrations without calmodulin present. Na+ produced effects similar to those of K+ in this preparation both in the presence and absence of calmodulin. The effect of calmodulin on the intermediate steps of the (Mg2+,Ca2+)ATPase in cardiac sarcoplasmic reticulum was also investigated. Calmodulin was found to reduce the steady-state level of the Ca2+-dependent phosphoprotein (ECaP) and increase the (Mg2+,Ca2+)ATPase activity of this preparation. Dephosphorylation of ECaP in the presence of Tris-ATP (0.5 mM) was significantly stimulated by calmodulin. These studies indicate that calmodulin stimulates Ca2+ transport in cardiac sarcoplasmic reticulum by increasing the turnover rate of the transport process.

Animals↗
PubMed1980

Structure-volume relationships: singular volume effects produced by cupric ion-globular protein interaction.

The nature of the volume isotherms produced by the coordination of Cu(II) with ovalbumin and bovine serum albumin differs substantially from the adsorption isotherms produced by these systems. Whereas there was increased binding of Cu(II) associated with a pH increase from pH 5.3 to pH 7.4, the volume isotherms for these systems did not exhibit this type of pH dependence. The volume changes were determined at 30.0 +/- 0.001 degrees C with microdilatometers which could be read to 0.01 muL. The binding isotherms for ovalbumin at pH 5.3 and 7.4 and for bovine serum albumin at pH 5.3 was resolved by a Scatchard plot to yield the appropriate thermodynamic parameters. An algorithm was derived to calculate the distribution of the individual PMi complexes, i.e., PMi-1 + M in equilibrium (Ki) PMi where i equals 1, 2, 3, ..., n moles of cation, M, bound per mole of protein, P, for the above systems. The volume isotherms were then resolved in terms of the constituent delta Vi terms, i.e., the volume change produced by the formation of the individual PMi complexes. These values were verified by an independent graphical differentiation procedure. The coordination of Cu(II) to BSA at pH 7.4 produced a cooperative adsorption isotherm which was not amenable to a Scatchard analysis. The resultant anomalous volume isotherm was resolved into a component related to Cu(II)-site interaction and a negative volume effect attributable to a conformational change induced by complex formation. This structural transition which occurs at physiological pH may constitute a control mechanism for regulating the serum level of Cu(II) and possibly other divalent ions.

Adsorption↗
PubMed1980

(Mg2+ + Ca2+)-ATPase activity in plasma membrane enriched preparations of human skin fibroblasts: decreased activity in fibroblasts derived from cystic fibrosis patients.

Plasma membrane enriched preparations obtained from cultured human skin fibroblasts by differential centrifugation and sucrose density centrifugation techniques were found to contain a Mg2+-dependent Ca2+-stimulated ATPase activity. The specific activity of the (Mg2+ + Ca2+)-ATPase present was 4-5-fold higher than that present in crude membrane preparations and 80-100-fold higher than that present in homogenates. The (Mg2+ + Ca2+)-ATPase activity of both crude and plasma membrane enriched preparations of cultured fibroblasts from cystic fibrosis patients was significantly reduced compared to that activity observed in age-matched controls. This study corroborates our previous observations made in crude homogenate preparations of fibroblasts and indicates another cell type where (Mg2+ + Ca2+)-ATPase activity may be altered in cystic fibrosis.

Calcium-Transporting ATPases↗
PubMed1980

Effects of spinal cord lesions on somatic evoked potentials altered by interactions between afferent inputs.

In cats anesthetized with alpha-chloralose, somatic evoked potentials (SEP) were recorded in response to electrical stimulation of surgically isolated peripheral nerves. Selected surgical lesions were made at T9-L1 spinal cord and were histologically verified. Two stimulus magnitudes were used to activate peripheral nerves, one only exciting the large fibers and another exciting the small fibers as well. Control SEPs were recorded in response to stimulation of both large and small fibers of the radial nerve. The later components (latencies greater than 40 msec) of this SEP were suppressed when evoked 100 msec after application of a conditioning stimulus (CS) to the large fibers of either peroneal nerve. Bilateral transection of the dorsal columns and spinocervical tracts eliminates these effects. Increasing the CS intensity to include small diameter fibers again resulted in reduction of the later components of the SEP. This interaction was largely eliminated if the transection was extended to include mid-lateral cord tracts. These results suggest that the SEP can be influenced by small fiber afferent activity conducted in mid-ventrolateral spinal cord in the absence of the dorsal columns and spinocervical tracts. Alterations in the forelimb-evoked SEP by a conditioning hindlimb stimulus is a sensitive indicator of spinal cord integrity. This method may be used to assess whether low spinal injury spares ventrolateral columns.

Afferent Pathways↗
PubMed1980

Cardiac contusion in the patient with multiple injuries.

We have treated 20 patients with multiple injuries and concomitant myocardial contusion. The diagnosis of myocardial contusion was based mainly on serial ECG tracings which showed arrhythmias, dynamic ischaemic patterns or conduction disturbances. The clinical and laboratory findings of cardiac contusion are sometimes indistinguishable from those found in multiple injuries. Furthermore, they are overshadowed by the overt manifestation of cerebral, thoraco-abdominal and skeletal injuries. Awareness and prompt diagnostic measures are essential in the diagnosis of cardiac injury. Strict cardiac monitoring following multiple trauma will prevent serious or even fatal outcome of cardiac injury.

Accidents, Traffic↗
PubMed1980

Uptake and release of chlorhexidine by bovine pulp and dentin specimens and their subsequent acquisition of antibacterial properties.

Bovine pulp and dentin specimens were treated with either a 0.02 or 1.00 percent solution of chlorhexidine for either 20 or 40 minutes. Culture determination of the acquisition of antibacterial properties by the treated specimens immediately and 1 week after the treatment was evaluated using the test organism Streptococcus faecalis. It was concluded that chlorhexidine is a potent antibacterial agent under the test conditions and that its use as an endodontic irrigating solution should be further evaluated.

Adsorption↗