Biomedical subjects
L Cohen
Publications and source records attributed to L Cohen.
Apgar scores and umbilical cord arterial pH in the breech neonate.
Apgar scores and umbilical cord arterial pH measurements of 449 singleton breech deliveries are compared retrospectively to those of 1425 singleton vertex neonates. In the vaginal deliveries the Apgar scores and umbilical arterial pH were higher for the vertex neonates. There were no differences in either Apgar scores or umbilical arterial pH between the breech and vertex neonates delivered by cesarean section. Whereas Apgar scores in the less than 1000 g and greater than or equal to 2500 g weight groups were lower in the breech neonates delivered vaginally compared to cesarean section, umbilical arterial pH measurements were similar. The data suggest that liberal use of cesarean section may improve the Apgar scores but will probably not appreciably improve the acid-base status of the breech neonate.
Neutron therapy in cervical cancer: results of a phase III RTOG Study.
Between October 1976 and May 1984, 156 patients with locally advanced cervical cancer were entered into a Phase III trial with the participation of five institutions. Patients were randomly assigned to receive photons only (50 Gy in 25 fractions over 5 weeks plus intracavitary applications or external-beam boost) or mixed-beam radiotherapy (2 fractions a week of neutrons, 3 fractions a week of photons to a total RBE-adjusted dose of 50 Gy over 5 weeks plus intracavitary applications or external mixed-beam boost). Only patients with squamous carcinoma of FIGO Stages IIB, III, or IVA with negative para-aortic nodes on lymphangiogram were eligible. Ten patients were excluded from the analysis because of ineligibility or cancellation. Of the 146 patients analyzed, 80 were treated with mixed-beam radiotherapy and 66 with photons. Patients were grouped by stage and institution. The percentage of patients undergoing intracavitary applications was 50% on mixed beam and 75% on photons (p less than 0.01). Tumor clearance was 52% and 72% for mixed beam and photons, respectively (p less than 0.03). Local control at 2 years was 45% for mixed beam and 52% for photons. Median survivals were 1.9 years on mixed beam and 2.3 years on photons. Severe complications occurred in 19% and 11% in mixed beam and photons respectively (p less than 0.13). The inferior outcome with neutron therapy in this study may have resulted from the use of horizontal neutron beams of varying energy and penetration. A new randomized trial using high-energy hospital-based cyclotrons with gantry-mounted beam-delivery systems has recently been activated to evaluate more rigorously the role of fast-neutron therapy for advanced cervical cancer.
A unified approach to dose-effect relationships in radiotherapy. I: Modified TDF and linear quadratic equations.
A linear quadratic factor analogue (LQF) to the variable-exponent TDF model is introduced. In both of these models, account is taken of the volume of tissue irradiated. Scaling factors are used such that an LQF or a TDF of 100 represents tolerance for each volume or partial volume of each tissue or organ irradiated. These models are sufficient for tissues which are irradiated fairly homogeneously. Examples illustrate the use of these models.
Re-irradiation of locally recurrent tumors with fast neutrons.
Forty-six patients with locally recurrent disease were re-irradiated with fast neutrons at Fermilab. All had received prior radical radiation therapy either with or without surgery. Six were palliative. Forty patients treated with curative intent were analyzed for local response, survival, and complications. The overall response rate was 78% (31/40); 50% (20/40) had a complete local response. Ten of 16 patients (63%) with non-epidermoid carcinomas in the head and neck regions had complete response, whereas only nine of twenty patients (45%) with epidermoid carcinomas were complete responders. In a subset of 12 patients with salivary gland type tumors, 10 had a complete response (83%). Two of these 10 patients are alive beyond 5 years. Observed median survival for the forty patients was 9.3 months, and for complete responders 14.4 months. Observed median survival for partial responders was only 7.5 months. Four of six patients treated for palliation had significant subjective improvement. Significant morbidity, Grade III or greater (EORTC/RTOG scale), was seen in only 10 patients (25%), and this was found to depend directly on the total dose delivered. We conclude that neutron beam therapy can be used as a therapeutic modality for patients with recurrent tumors with an acceptable degree of morbidity.
Importance of variables affecting pit and fissure sealant use in the United Kingdom.
A mail survey of 1000 dentists representing the general population of practising dentists in Great Britain and Northern Ireland was conducted to identify those factors most predictive of sealant use. The response rate obtained was 73.7%. The mean percentage of patients aged 18 and under receiving sealants was 13.4 (SD 20.7). For both respondents who had received sealant training in dental school and those who had not, the three variable groupings having the strongest correlation with levels of sealant use were preventive orientation, opinion about sealants, and patient influence. Multiple regression analyses reflected these simple correlations. For both sealant educated respondents (R2 = 39%) and respondents without sealant education (R2 = 49%), the best combination of variables predicting sealant use were preventive orientation, opinion about sealants, and patient influence.
The use of pit and fissure sealants in private practice: a national survey.
The slowness in the adoption of sealant use has been caused by many interrelated professional, scientific, social, and economic factors. To study these factors, data were collected by the use of mail questionnaires sent to a representative sample of 3,504 private practice general dentists. The average percent of patients 18 years of age and younger receiving sealants was 18.7. Nearly one-third of the respondents indicated that none of their patients received sealants. Data describing the following factors were obtained: demographic background, sealant awareness, attitudes and knowledge about sealants, and decision-making factors. We concluded that professional organizations should take a more active role in promoting sealants to dentists, professional organizations and governmental agencies should increase efforts to inform patients/consumers of the benefits of sealants, guidelines for sealant use should be developed, state boards should permit the delegation of sealants to trained auxiliaries, and sealant manufacturers should make more effort to advertise and promote sealants.
Anomalous left coronary artery arising from the pulmonary artery in infancy: is early operation better?
From January 1975 to January 1987, 21 consecutive infants aged less than six months (mean (SD) 2.6 (1.2] were admitted with anomalous origin of the left coronary artery from the pulmonary artery. In the first 12 patients, who were seen up to 1982, operation was performed after the age of one year (mean (SD) 29 (29) months) (group 1). The next nine infants, seen from 1983 to 1987, had their operations within a few weeks of the onset of symptoms (mean (SD) age 4.8 (1.4) months) (group 2). In group 2 the left coronary artery was relocated into the aorta, whereas in group 1 there was additional resection of the left ventricular wall or mitral valvoplasty or both. At presentation there were no differences in age, clinical condition, heart enlargement, and echocardiographic left ventricular dysfunction between groups 1 and 2. Seven of the 12 patients in group 1 died, five while they were awaiting operation (three died suddenly at home) and two at operation. The five survivors are doing well 6.4 (3.1) years after operation with normal left ventricular function which improved slowly over several months after operation. Two of the nine patients in group 2 died; both deaths occurred at or soon after operation. The seven survivors are doing well 1.8 (0.9) years after operation. In three, left ventricular function recovered within three weeks; and there was even partial or total regression of the Q waves in the supposedly necrotic areas. In the remaining four the pattern of improvement in left ventricular function resembled that in group 1. Operation should be undertaken early in infants with anomalous left coronary artery arising from the pulmonary artery because the procedure is relatively safe, prevents a high natural mortality, and offers a better chance of a faster recovery of left ventricular function.
Postural adjustments associated with rapid voluntary arm movements. II. Biomechanical analysis.
Normal subjects performed bilaterally symmetric rapid elbow flexions or extensions ("focal movements") while standing. Specific patterns of electromyographic activity in leg and trunk muscles ("associated postural adjustments") were seen for each type of movement. The biomechanical significance of these postural adjustments was analysed by means of the ground reaction forces and motion of the various body segments. Experimental data were compared with that from a theoretical model of the body consisting of a six segment kinetic chain with rigid links. Distinct patterns of the ground reaction forces with elbow flexion were opposite in direction to those seen with elbow extension. Movements of the various body segments were small and specific for a certain focal movement. Dynamic perturbations arising from the arm movement in an anteroposterior direction were found to be compensated by postural adjustments, whereas vertical perturbations were not compensated. The muscular activity acting about different joints in the different movements was found to correlate with the predictions of activity needed to compensate for net joint reaction moments arising from the focal movement. Motion of the various body segments could be understood as resulting from the interplay of the net reaction moments and the net muscular moments at the different joints. Dynamic postural requirements are accomplished by a precise active compensation initiated before the focal movement.
Outpatient extracorporeal lithotripsy of kidney stones: 1,200 treatments.
1,200 extracorporeal lithotripsies have been performed in 816 patients. 58% of the stones had a diameter of 3-10 mm, 41% measured between 11 and 20 mm and 1% were larger than 20 mm. The patients were all treated on an outpatient basis without either anesthesia or analgesia. The mean time spent at the lithotripsy center was 2 h: the mean treatment time was 46 min, i.e. 3,450 shocks at a frequency of 1.25/s. 530 patients were reviewed after 3 months. Overall, 64% of them were stone free. These results varied between 73% for stones less than 10 mm in diameter and 43% for stones larger than 20 mm in diameter. 69% of the patients presenting with a single stone were stone free at 3 months. The best results were obtained in upper caliceal stones (78%) and the least satisfactory results were obtained in the lower caliceal stones (68%). The complication rate was low: renal colic in 18% of cases, fever in 2% of cases. Altogether, 13 disobstructions were required, namely 12 endoscopic and 1 surgical. 33% of patients were retreated without admission to hospital. Outpatient extracorporeal piezoelectric lithotripsy is indicated for renal pelvic or caliceal stones less than 20 mm in diameter situated in a nonobstructed renal cavity, in a noninfected patient without any particular risk factors. 85% of patients are currently treated at the lithotripsy center on an outpatient basis.
Pit and fissure sealant use in private practice: influence of state practice acts.
To study the influence of the delegation of sealant procedures to auxiliaries on sealant use, we queried a national sample of general dentists and pedodontists. A large percentage (34-58 per cent) of both groups were unaware or mistaken in their perception of the legality of delegating sealants. Although perception of legality to delegate was associated with increased sealant use, a large percentage (33-59 per cent) of both groups did not delegate even when it was perceived legal to do so.
Effects of labeling patients "psychiatric" or "medical": favorability of traits ascribed by hospital staff.
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Cardiomyopathy and multiple myeloma. Complications of scleredema adultorum.
Multiple myeloma and congestive heart failure developed in a patient with long-standing scleredema adultorum. Staining of the myocardium, performed after her death, was positive for acid mucopolysaccharide and negative for amyloid. To the best of our knowledge, this is the first case in which acid mucopolysaccharide has been demonstrated in the myocardium, thus explaining the cardiomyopathy of scleredema adultorum. Review of the world literature enabled us to identify a statistically significant increased prevalence of plasma cell dyscrasia among patients with protracted scleredema. In all patients, plasma cell dyscrasia appeared years after the onset of scleredema. Immunofluorescent studies were negative for immunoglobulin deposition. We assume, therefore, that the plasma cell dyscrasia was secondary to scleredema.
Free-flap surgery: nurses make it work.
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Recent data on magnesium and osteoporosis.
Larger and more perfect bone mineral crystals and decreased bone magnesium concentration were found in postmenopausal osteoporosis, senile osteoporosis, alcoholic osteoporosis and osteoporosis associated with thalassaemia. The decreased bone magnesium concentration and the increased retention of magnesium in the magnesium load test suggest magnesium deficiency in post-menoposal osteoporosis, probably caused by magnesium malabsorption.
High serum magnesium and the renin-aldosterone axis: a personal analysis.
High concentrations of extracellular Mg in the rat and sheep but not in man stimulate renin secretion. High concentrations of Mg inhibit aldosterone secretion in dog and man but not in the sheep.
Cytology of concomitant oral lesions.
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Alzheimer's Disease Assessment Scale (ADAS).
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