Biomedical subjects
S Rush
Publications and source records attributed to S Rush.
Comprehensive management including interstitial brachytherapy for locally advanced or recurrent gynecologic malignancies.
Radical therapy for locally advanced or recurrent gynecologic malignancies (LARGM) may include interstitial brachytherapy (IB) when intracavitary brachytherapy is impossible or inadequate and external beam teletherapy would be limited by surrounding normal tissue tolerance. Sixteen women received IB as all or part of their treatment at North Shore University Hospital for the treatment of locally advanced primary or recurrent tumors of gynecologic origin from May 1988 through September 1990. Primary sites included the vulva (3), vagina (2), cervix (7), and endometrium (4). Radiosensitizing chemotherapy was used in 8 patients. With a median follow-up of 23 months (range, 12-44 months), 11 patients (69%) have experienced continuous local control of their tumor and 4 patients (25%) have experienced severe complications. While significant risks may attend the use of IB, IB is an integral part of management for select patients with LARGM.
Molecular cloning of calmodulin mRNA species which are preferentially expressed in neurons in the rat brain.
A cDNA clone designated NGB, which was isolated from a rat brain expression library, detected two mRNA species of 1.8 and 4.0 kb which are highly enriched in brain tissue. cDNAs NGB1 and NGB2 corresponding to these two mRNAs have been isolated and characterized. Sequence data showed that both mRNA species contain the same open reading frames but differ in their 3' untranslated regions. The open reading frame encodes a calmodulin protein of 148 amino acids. Both mRNA species are derived from the rat CaMI gene by utilization of different polyadenylation addition sites. Analysis of the 3' untranslated sequence which is unique to the larger mRNA species revealed a putative AU-rich 'destabilizer' sequence which is thought to be involved in mechanisms of selective mRNA breakdown. In situ hybridization studies revealed that the two calmodulin mRNAs are expressed strongly in neuronal cells in the adult rat brain. Levels of the two mRNA species increased during early postnatal development.
Fraction size in external beam radiation therapy in the treatment of melanoma.
RTOG 83-05 was a prospective randomized trial evaluating the effectiveness of high dose per fraction irradiation in the treatment of melanoma. Retrospective analysis suggested a dose response curve of melanoma to external beam irradiation as the dose per fraction is increased. RTOG 83-05 randomized patients with measureable lesions to 4 x 8.0 Gy in 21 days once weekly to 20 x 2.5 Gy in 26-28 days, 5 days a week. One hundred thirty-seven patients were randomized and 126 patients were evaluable: 62 patients in the 4 x 8.0 Gy arm and 64 patients in 200 x 2.5 Gy arm. Patient characteristics were essentially identical. Stratification was performed on lesions less than 5 cm or greater than or equal to 5 cm. The study was closed on May 31, 1988 when interim statistical analysis suggested that further accrual would not reveal a difference between arms. Response rate overall was complete remission 23.8%, partial remission 34.9%. The 4 x 8.0 Gy arm exhibited a complete remission of 24.2% and partial remission of 35.5%. The 20 x 2.5 Gy arm exhibited a complete remission of 23.4% and partial remission of 34.4%. There was no difference between arms.
The use of intraoperative transabdominal ultrasound in gynecologic brachytherapy.
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Prolactin reduction after combined therapy for prolactin macroadenomas.
The ability of surgery or bromocriptine to produce endocrine control of a prolactin macroadenoma decreases as the prolactin level increases. Guidelines for the use of multimodality therapy have not been developed for tumors associated with markedly elevated prolactin levels. We reviewed the records of 21 patients with prolactin levels greater than 200 ng/ml treated by transsphenoidal surgery and postoperative radiotherapy with or without a dopamine agonist. Values before and after treatment were available for 19 patients (13 men and 6 women). The mean basal prolactin level before treatment for the entire group was 2410 ng/ml. Surgery and radiotherapy resulted in a 90% reduction and serum prolactin levels within normal limits in 0 of 7 patients, versus the combination of surgery, radiotherapy, and dopamine agonist, which resulted in a 99.5% reduction and values within the normal range in 12 of 12 patients. Spontaneous physiological improvement was not often observed. One woman and two men were able subsequently to have children. A plan for these patients is discussed.
Treatment of aggressive keratoacanthomas by radiotherapy.
Keratoacanthomas infrequently are treated by radiotherapy. However, keratoacanthomas that are recurrent after surgical excision or whose resection would result in cosmetic deformity may benefit from radiotherapy. Between January 1970 and June 1988, 29 such keratoacanthomas in 18 patients were irradiated. Doses ranged from 3500 cGy in 15 fractions to 5600 cGy in 28 fractions. Measured end points of therapy were (1) initial response, (2) freedom from recurrence, and (3) quality of the subsequent cosmetic appearance (scored as good, fair, or poor). No lesion progressed and all eventually regressed completely. Cosmetic results generally were considered good by both the patient and the referring dermatologist; none of the results was considered poor. Our results demonstrate that radiation is an effective means of treating keratoacanthomas.
EMG to torque relationship in rectus abdominis muscle. Results with repeated testing.
Rectus abdominis muscles of young healthy female volunteers were studied to determine both the maximum strength in isometric flexion and the relation between the surface electromyogram (RMS EMG) and torque. Both the upper and lower portions of the abdominal muscle were studied during graded increase and decrease of torque. Repeated testing was performed over 6 weeks. The form of the relation between torque and EMG was better described by a quadratic than by a linear regression relationship, but with considerable variability about the best-fit line. The torque-increasing and torque-decreasing parts of each test were different and were analyzed separately. After 6 weeks of repeated testing, maximum voluntary isometric flexion torque increased 16.8% (P less than 0.01). There was a decrease in the ratio of electromyographic activity to torque production, which was statistically significant in the torque-increasing recordings. These changes in maximum torque and in the EMG-torque relation were attributed to learning through a test-retest effect, rather than to a true change in muscle characteristics. These findings, which show changes in normal subjects undergoing repeated testing, do not support the reliability of isometric strength measurements, or measurements based on RMS EMG recordings, for quantifying abdominal muscle function in patients with back pain, or those undergoing strengthening exercises.
Rat and mouse identifier sequences are preferentially but not exclusively located in cortical neuronal genes expressed postnatally.
A genetic element called the identifier (ID) sequence, highly repeated in the rat genome, has previously been reported to be located in the introns of some genes transcribed in the adult rat brain by RNA polymerase II (Pol II). We show that nuclear RNA isolated from neurons of cerebral hemispheres (cortex) of 14-day old rats is enriched more than 10-fold in ID sequences compared to nuclear RNA from liver, kidney, cerebellum, or cortical glia. The developmental onset of the difference is during the first 2 weeks after birth. Mouse cortical neuronal nuclear RNA is similarly enriched in an element related but not identical to the rat ID element, and the enrichment also has postnatal onset. The enriched appearance of ID sequences in transcripts whose expression is increased postnatally in cortical neurons correlates developmentally and spatially with the transcription of ID elements by RNA polymerase III (Pol III) and with a change in chromatin structure.
Optimisation of the locations of multiple-dipole heart generators in a simple torso model.
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A practical algorithm for solving dynamic membrane equations.
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Relationships among Green's theorem, Helmholtz' theorem, and integral equation methods of solving the forward ECG problem.
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Response of cultured myocardial cells to countershock-type electric field stimulation.
Myocardial cells isolated from 8-day chick embryos were grown in monolayer culture under conditions that produce "standard embryonic" and "adult-type" cells. These cells were subjected to electric field stimulation that had a waveshape and intensities similar to those used in clinical electric countershock procedures. Photocell mechanograms obtained before, during, and after stimulation were correlated with simultaneously measured transmembrane potentials to determine the relationship between membrane polarization and arrhythmia production that occured after the stimulus. The results of these experiments demonstrate that a predictable sequence of mechanical responses occurs after stimuli ranging in intensity from 6 to 200 V/cm. This sequence, which closely resembles that observed in vivo after similar stimulation intensities, consists of a single response (activation), tachyarrhythmia, relaxed arrest followed by transient tachyarrhythmia, arrest with contracture, and cellular fibrillation. This diverse pattern of arrhythmias is associated with a prolonged depolarization of the cell membrane which increases with the intensity of the applied stimulus. It is probable that this depolarization is caused by a transient electromechanical deformation of the cell membrane during the shock. These findings contribute to a better understanding of the causes of the arrhythmias that appear after clinical and experimental electric countershock procedures.
Local potential gradients as a unifying measure for thresholds of stimulation, standstill, tachyarrhythmia and fibrillation appearing after strong capacitor discharges.
The pattern of arrhythmias following capacitor discharges of increasing amplitude, which have been observed by the authors in cultured myocardial cells from chick embryos, was compared to the arrhythmia patterns caused by similar discharges in experimental animals and humans, as reported in the literature. While the absolute voltages and currents causing each type of arrhythmia showed great variation, the scatter decreased considerably when the stimulus level was recalculated on the basis of peak current density in myocardial tissue, and was reduced further when the peak potential gradient at the cell level was used as the common basis of comparison. The similarity in the arrhythmia patterns and in the voltage gradients at which they occur indicates that the mechanism of these arrhythmias may be similar in cultured cells and intact animals and humans.
Application of a muscle-potential monitor to electroconvulsive therapy.
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Some quantitative estimates of inhomogeneity effects in electrocardiography.
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Current density in bilateral and unilateral ECT.
This paper describes a method of computer simulation which will enable the researcher to test, on the theoretical level, the effects of a wide variety of electrode placements, currents, tissue resistivities, and volumetric differences on the distribution of current within the brain. It is based on a nonhomogenous, threesphere model of the head and is capable of expansion to account for known inhomogenities within the brain. It should prove a useful research tool for a wide variety of purposes.
On the independence of magnetic and electric body surface recordings.
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