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Biomedical subjects

K Rosen

Publications and source records attributed to K Rosen.

At least 37 records · Page 2Linked to original sources
PubMed1989

Ultrasound: effectiveness of treatments given under water.

The purpose of this study was to determine whether ultrasound treatments given with a limb immersed in tap water are as effective in heating the tendons overlying a superficial bony prominence as ultrasound treatments given with the applicator and coupling agent in direct contact with the limb. The lateral epicondyle of a pig was treated with the applicator in contact with the limb and with the limb immersed in a water bath with the applicator held 2cm from the skin surface. With a thermocouple inserted into a 20-gauge needle, the temperature elevations in the tendon of the extensor muscles originating at the lateral epicondyle were measured. It was found that the temperatures of the tendons rose into the therapeutic range when the ultrasound was applied directly to the skin surface, but not when treatment was given under water. It is therefore preferable to give ultrasound treatments with the applicator in direct contact with the subject rather than in an immersion bath with tap water as the coupling agent.

Animals↗
PubMed1988

A reversible pulmonary artery band: preliminary experience.

Pulmonary artery banding has become an infrequently used surgical technique. However, if a band was developed that could be relieved without the need for open heart surgery, it is likely that pulmonary artery banding would be used more frequently in the management of infants with congenital heart disease. Such a pulmonary artery band was placed in seven 1 week old mongrel puppies by using a loop of an absorbable suture material (Vicryl). One dog died at 2 months as a result of right ventricular failure. The remaining six dogs underwent cardiac catheterization and pulmonary balloon angioplasty at 6 months of age. After measuring pulmonary artery, right ventricular and aortic pressures and performing a right ventricular angiogram, balloon angioplasty of the band site was performed. A 20 mm balloon angioplasty catheter (Medi-Tech) was used in all dogs. Balloon angioplasty decreased right ventricular pressure from 101 +/- 19 to 42 +/- 3 mm Hg (p less than 0.05) and right ventricular systolic outflow tract gradient from 59 +/- 14 to 7 +/- 2 mm Hg (p less than 0.03), and increased the size of the band site from 8.7 +/- 0.03 to 14.9 +/- 0.5 mm (p less than 0.01). All dogs were recatheterized 2 months after angioplasty and were then killed for pathologic evaluation. At follow-up catheterization, right ventricular pressure, right ventricular outflow tract gradient and pulmonary artery size at the band site remained at the values obtained immediately after angioplasty. Postmortem examination demonstrated that there was no evidence of pulmonary artery damage. Although these studies are preliminary, they suggest that a reversible pulmonary artery band can be performed.

Angioplasty, Balloon↗
PubMed1988

Fentanyl uptake by the scimed membrane oxygenator.

With the initiation of cardiopulmonary bypass (CPB), using a membrane oxygenator, the drop in circulating fentanyl concentration is greater than can be attributed to dilution alone. This study examined the Scimed brand (2A-800) membrane oxygenator as a site of fentanyl binding. Initial experiments used an assembled CPB circuit. Subsequent dissection and analysis of the oxygenator revealed that the silicone-based membrane sheets were the primary site of fentanyl binding. The silicone-containing waterproof wrapper was also responsible for 1% to 2% of fentanyl binding. Binding of fentanyl to the Scimed membrane oxygenator occurs at a rapid rate and continues until the membrane has taken up 130 ng/cm2 of membrane surface area. The interaction is complete by 15 to 30 minutes if suprasaturated concentrations are used. Samples of membrane material with a surface area of 1 cm2 were also studied. Isolated membrane squares in a nonmoving prime solution required two hours for saturation at the same fentanyl concentrations as the intact membrane with circulating prime. Introduction of motion to the priming solution accelerated the rate of fentanyl binding by the isolated membrane squares to a rate similar to the intact membrane. Motion also provided results similar to those previously reported using different analysis techniques. Therefore, this method of studying fentanyl-membrane interactions using samples of membrane and tritiated fentanyl is a valid model for the intact membrane oxygenator in the assembled bypass circuit. In addition to solution movement, fentanyl concentration of the priming solution was also found to affect the rate of fentanyl uptake. When fentanyl concentrations were used which were insufficient to achieve saturation of the membrane (10 ng/mL and 20 ng/mL), the rate of uptake was slowed. Binding of all available fentanyl under these conditions occurred within three hours. There is potential modification of this interaction by several clinically relevant factors, including temperature, pH, protein content of prime solution, and other drugs. These areas require further study before the saturation data are applied to clinical practice.

Absorption↗
PubMed1987

Normal cellular counterparts of B cell chronic lymphocytic leukemia.

In an attempt to compare B cell chronic lymphocytic leukemia (B-CLL) with its normal cellular counterpart, the cell surface phenotype of 100 cases of B-CLL was determined by using a panel of monoclonal antibodies (MoAbs) directed against B cell-restricted and -associated antigens. The majority of B-CLL cells expressed Ia, B4 (CD19), B1 (CD20), B2 (CD21), surface immunoglobulin (sIg), and T1 (CD5) but lacked C3b (CD35) receptors. In contrast, the overwhelming majority of small unstimulated B cells expressed Ia, B4, B1, B2, sIg, and C3b receptors but lacked detectable T1. Small numbers of weakly sIg+ cells could be identified in peripheral blood and tonsil that coexpressed the B1 and T1 antigens. Approximately 16% of fetal splenocytes coexpressed B1, T1, weak sIg, B2, and Ia but lacked C3b receptors and therefore closely resembled most B-CLL cells. With the phenotypic differences between the majority of small unstimulated B cells and B-CLL cells, we examined normal in vitro activated B cells and B-CLL cells for the expression of B cell-restricted and -associated activation antigens. Of 20 cases examined, virtually all expressed B5, and approximately 50% of the cases expressed interleukin-2 receptors (IL-2R) and Blast-1. Normal B cells were activated with either anti-Ig or 12-0-tetradecanoylphorbol-beta-acetate (TPA) and then were examined for coexpression of B1, T1, and the B cell activation antigens B5 and IL-2R. Only cells activated with TPA coexpressed B1 and T1 as well as B5 and IL-2R. B cells activated with either anti-Ig or TPA proliferated in the presence of IL-2, whereas B-CLL cells did not, although they all expressed the identical 60-kilodalton proteins by immunoprecipitation. These studies are consistent with the notion that B-CLL resembles several minor subpopulations of normal B cells including a population of B cells that are activated in vitro directly through the protein kinase C pathway.

Antibodies, Anti-Idiotypic↗
PubMed1983

Tests of a two-stage model of visual matching.

Predictions from a model of visual matching were tested in two experiments. The model consists of a wholistic comparison process followed by an element-by-element comparison process. All stimuli are processed by the first stage but only those that permit a decision based on a wholistic comparison produce responses. When discrimination is difficult and a decision cannot be reached by a wholistic comparison, the second stage of processing is initiated. Degree of discriminability and stimulus duration (100 and 1000 msec.) were varied in both experiments. In Exp. 1, the stimulus elements were arranged in a square configuration to facilitate a wholistic comparison. As predicted, the hard-different stimuli took longer to match than the same or easy-different stimuli. The hard-different stimuli presented for 1000 msec. took longer to match than those presented for 100 msec. There was no difference in accuracy between responses to hard-different pairs at the two durations. In Exp. 2, the stimulus elements were arranged in a horizontal row and placed one above the other to facilitate element-by-element comparison. As predicted, these stimuli produced slower and more accurate responses for same and hard-different stimulus pairs only when they were exposed for 1000 msec. Responses to easy-different stimulus pairs were made quickly and accurately.

Adult↗
PubMed1982

Aprindine-induced polymorphous ventricular tachycardia.

Five cases of aprindine-induced polymorphous ventricular tachycardia (torsade de pointes) are presented. In four cases, polymorphous ventricular tachycardia appeared after the oral administration of 400 mg of aprindine. One patient had mild hypokalemia at the time of polymorphous ventricular tachycardia so that a direct cause and effect relation between the drug and the tachycardia cannot be established. All five patients manifested Q-T prolongation and recurrent syncope due to polymorphous ventricular tachycardia. In all five, polymorphous ventricular tachycardia subsided once administration of aprindine was discontinued.

Aged↗
PubMed1982

The conduction system in Pompe's disease.

We report our findings in the microscopic examination of the conduction system in four infants with glycogen storage disease, one of whom had adequate electrophysiologic studies. The electrophysiologic studies in the latter case showed P-A and A-H intervals at the lower limits of normal, but the H-V interval was just above the normal mean. This suggests that the rapid conduction was not localized in the anatomic counterpart of the H-V interval. The short P-R interval in the ECG may be related to the enlargement of cells, which may in turn be related to increased glycogen content. The relationship of glycogen per se to the speed of conduction is unknown. We found that the summit of the ventricular septum bulged, probably because of the generally increased cell size, and that the topography of the atrioventricular conducting system was different from normal. This is possibly related both to an increase in the cell sizes of the specialized conducting tissue itself and to deforming effects of this bulging summit of the ventricular septum. New microscopic details of the components of the conducting system are described in these cases.

Cardiomegaly↗
PubMed1982

Symptomatic spontaneous paroxysmal AV nodal block due to localized hyperresponsiveness of the AV node to vagotonic reflexes.

Two apparently healthy patients had recurrent syncope with documented paroxysmal AV block. In both patients the site of AV block was demonstrated to be in the AV node. Coronary angiography (in both patients) and sustained deep inspiration (one patient) reproducibly initiated episodes of paroxysmal AV nodal block (identical to spontaneous episodes). Atropine abolished further attempts of AV block induction. Vagal hyperresponsiveness was limited to the AV node, since the interventions provoking paroxysmal AV nodal block produced only appropriate sinus slowing. This syndrome reflects hyperresponsiveness of the AV node to vagotonic reflexes, and exists as a clinically significant entity producing recurrent syncope.

Adult↗
PubMed1982

Serial electrophysiologic studies in patients with chronic bundle branch block.

Serial His bundle recordings were obtained during 1:1 atrioventricular (AV) conduction in 90 patients with chronic bundle branch block over a mean interval of 30 months. Atrioventricular conduction time (AH) increased greater than or equal to 10 msec in 25 (28%) and infranodal conduction time (HV) increased greater than or equal to 8 msec in 29 (32%), but only 10 patients had parallel increases in AH and HV intervals. Increases in conduction times were independent of age, time interval between studies, cause of heart disease or initial AH or HV intervals. Women were significantly more likely than men to show an increased HV interval and spontaneous trifascicular block. Spontaneous progression to second- or third-degree AV block occurred at the AV node in seven patients and below the node in 12 patients. The initial AH interval was prolonged in five of seven patients (71%) with AV nodal block and had increased further in only two at restudy. The initial HV interval was abnormal in eight of 12 patients (67%) who progressed to infranodal block and was prolonged further in eight at restudy. We conclude that in patients with chronic bundle branch block, (1) approximately 33% show progressive AV conduction system disease and AV nodal and infranodal disease progress independently; (2) progression of infranodal disease is more common in women; (3) AV nodal disease progress independently; (2) progression of infranodal disease is more common in women; (3) AV nodal disease is a common cause of AV block and can occur without further prolongation of the AH interval once a critical level of disease is attained, whereas infranodal block is usually accompanied by progressive lengthening of the HV interval; and (4) progression of AV conduction disease is not readily predictable from clinical and electrophysiologic variables.

Aged↗
PubMed1981

Radionuclide regurgitant index: value and limitations.

The radionuclide regurgitant index, defined as left ventricular/right ventricular stroke counts obtained from gated equilibrium studies, has been reported to predict the presence and severity of left-sided valve regurgitation. This study evaluated the radionuclide regurgitant index in 100 patients in whom left-sided valve regurgitation was angiographically graded (0 to 4+) with regard to most severe mitral or aortic regurgitation. Regurgitation was graded 0 in 44 of the 100 patients, 1+ in 22, 2+ in 8, 3+ in 6 and 4+ in 20. The radionuclide regurgitant index was 0.9 to 1.5 in 51 patients, 1.6 to 2.4 in 23 and 2.5 to 12.0 in 26. The mean radionuclide regurgitant index was 1.34 in the group with no regurgitation and 1.60 in those with 1+, 2.01 in those with 2+, 2.80 in those with 3+ and 3.85 in those with 4+ regurgitation. There was a significant difference (p less than 0.05) in the radionuclide regurgitant index between patients with no regurgitation and each group with regurgitation and between groups with regurgitation separated by two or more grades of angiographic regurgitation. Twelve patients had a discordant radionuclide regurgitant index; their index either predicted clinically significant or severe regurgitation when they had no or trivial regurgitation, or predicted no or trivial regurgitation when they had clinically significant regurgitation. Eight of 10 patients with a left ventricular ejection fraction of less than 0.30 had a discordant index (p less than 0.0005). All three patients with mitral valve prolapse associated with frequent ventricular extrasystoles had a discordant index (p less than 0.0005).

Adolescent↗
PubMed1980

The anatomic substrate for preexcitation in corrected transposition.

We report three cases of corrected transposition (CT), all with Ebstein's disease, ventricular septal defect (VSD) and ventricular preexcitation. In cases 1 and 2, the ECG revealed sinus rhythm, with type A fusion preexcitation QRS complexes, suggesting left-sided Kent bundles and intact conduction system (CS). Complete serial section (SS) of the CS in both cases revealed an anterior CS and a Kent bundle in the posteroseptal wall of the morphologic right ventricle (MRV). Case 3 had intermittent preexcitation, with periods of complete atrioventricular (AV) block with narrow QRS escape rhythm. The preexcitation complexes suggested the presence of a left lateral Kent bundle. SS of the CS revealed a blind posterior and two anterior AV nodes, one on either side of the pulmonary trunk. The left anterior AV node was blind. The right anterior node formed the anterior bundle, which ended blindly. This bundle emerged again and joined a posterior bundle to form an interrupted sling around the closed VSD. In addition, there was a tenous Kent bundle at the posterolateral wall of the MRV. In summary: (1) preexcitation in CT with Ebstein's disease of the left AV valve is associated with Kent bundles; (2) fusion complexes reflected intact CS; and (3) intermittent preexcitation with AV block was associated with the presence of tenuous Kent bundl and discontinuity of the CS.

Atrioventricular Node↗
PubMed1980

Echocardiographic demonstration of porcine mitral valve vegetation and dehiscence.

The echocardiographic study of a patient with a malfunctioning porcine valve in the mitral position is presented. Echocardiography of the mitral valve revealed multiple, dense heterogeneous echoes behind and within the valve stent which were suggestive of vegetations. At the aortic valve level, a clear systolic echo in the left atrium was recorded. This echo probably represented the prolapsing anterior valve stent and was caused by a major dehiscence of the valve stent due to endocarditis.

Adult↗
PubMed1978

Normalization of bundle branch block patterns by distal His bundle pacing. Clinical and experimental evidence of longitudinal dissociation in the pathologic his bundle.

Clinical and experimental observations in which bundle branch block patterns (BBBP) in ECG leads were normalized by distal His bundle (H) pacing are reported. The clinical material includes four patients with acute right BBBP secondary to anterior wall myocardial infarction and three patients with chronic left BBBP. Six of the seven patients had a prolonged H-V interval (60-85 msec) including three who showed evidence of an intra-H conduction delay (IHCD) with split H (H and H'). Distal H pacing from a right-sided electrode catheter normalized the BBBP with a stimulus-to-QRS (PI-V) interval 20-35 msec shorter than the H-V interval and almost identical to the H'-V interval in the three patients with documented IHCD. In 18 dogs ligation of the anterior septal artery resulted in IHCF with split H associated with right or left BBBP. Distal H pacing from catheter and/or plunge wire electrodes normalized the BBBP in 12 experiments (67%) with a PI-V interval identical to the H'-V interval. H pacing was selective and direct stimulation of myocardium was excluded by monitoring the high ventricular septal electrogram. The clinical and experimental observations are discussed as evidence that functional longitudinal dissociation is probably only operative in the pathologic H due to selectively greater depression of conduction in the transverse interconnections.

Animals↗
PubMed1976

A quantitative description of normal AV nodal conduction curve in man.

The AV nodal conduction curve generated by the atrial extrastimulus technique has been described only qualitatively in man, making clinical comparison of known normal curves with those of suspected AV nodal dysfunction difficult. Also, the effects of physiological and pharmacological interventions have not been quantifiable. In 50 patients with normal AV conduction as defined by normal AH (less than 130 ms), normal AV nodal effective and functional refractory periods (less than 380 and less than 500 ms), and absence of demonstrable dual AV nodal pathways, we found that conduction curves (at sinus rhythm or longest paced cycle length) can be described by an exponential equation of the form delta = Ae-Bx. In this equation, delta is the increase in AV nodal conduction time of an extrastimulus compared to that of a regular beat and x is extrastimulus interval. The natural logarithm of this equation is linear in the semilogarithmic plane, thus permitting the constants A and B to be easily determined by a least-squares regression analysis with a hand calculator.

Adult↗
PubMed1975

Comparison of cardiac refractory periods in children and adults.

Atrial (A) and A-V nodal (AVN) effective and functional refractory periods (ERP & FRP) were determined by atrial extrastimulus technique in 40 children, aged 7 months to 16 years, with normal P-R intervals and QRS durations. These data were compared to adult data at longest cycle lengths (CL) assuring atrial capture. All values are listed in msec as means plus or minus standard errors of the means. CL was 566 plus or minus 15 in children and 699 plus or minus 29 in adults (P less than .001). Refractory periods (RP) in children and adults were, respectively: AERP 196 plus or minus 9 and 239 plus or minus 13 (P less than .01), AFRP 225 plus or minus 8 and 284 plus or minus 11 (P less than .001), AVNERP 239 plus or minus 11 and 293 plus or minus 7 (P smaller than .001), AVNFRP 360 plus or minus 13 and 403 plus or minus 7 (P smaller than .005). RP were then compared at three equivalent CL ranges: CL1, 850-600; CL2 599-460; CL3 459-280. The following RP were significantly shorter in children (P smaller than .05-.001): AERP, AFRP, AVENERP and AVNFRP at CL2 and CL3. RP of the bundle branches were compared and tended to be shorter in children. In conclusion, atrial and A-V nodal ERP and FRP are shorter in children than adults. This shortening is only partially related to the shorter CL in children. These data are germane to understanding the maturation of the conduction system in man.

Adolescent↗