Biomedical subjects
D Fried
Publications and source records attributed to D Fried.
[Illnesses of Charles Darwin].
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[Harvey Cushing--the man behind the syndrome].
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Lasers in dentistry.
Since the development of the ruby laser by Maiman in 1960, there has been great interest among dental practitioners, scientists, and patients to use this tool to make dental treatment more pleasant. Oral soft tissue uses are becoming more common in dental offices. The possible multiple uses of lasers in dentistry, beyond soft tissue surgery and dental composite curing, unfortunately, have not yet been realized clinically. These include replacement of the dental drill with a laser, laser dental decay prevention, and laser decay detection. The essential question is whether a laser can provide equal or improved treatment over conventional care. Safe use of lasers also must be the underlying goal of proposed or future laser therapy. With the availability and future development of different laser wavelengths and methods of pulsing, much interest is developing in this growing field. This article reviews the role of lasers in dentistry since the early 1960s, summarizes some research reports from the last few years, and proposes what the authors feel the future may hold for lasers in dentistry.
Light deposition in dental hard tissue and simulated thermal response.
Near-IR (approximately 1 micron) lasers are presently used for a variety of intra-oral applications including dental hard tissue ablation, although the light intensity distribution and subsequent heating of the hard tissue are still poorly understood. This paper presents a detailed numerical study of the scattered light intensity distribution along with the corresponding predicted thermal response. The calculations are based on recently published scattering and absorption data for dental hard tissue around 1 micron. Our simulations indicate strongly enhanced energy deposition and concomitant heating near the dentino-enamel junction (DEJ), mainly due to the higher absorption in dentin. We predict from 10 to 20 times higher internal temperatures near the DEJ compared with the surface. For example, for 50-ms pulses of 5-J energy on a 3-mm-diameter spot (approximately 1 kW/cm2 or approximately 50 J/cm2), one can expect internal temperatures near the DEJ in excess of 100 degrees C. Elevated temperatures are predicted to extend far into the dentin, endangering the vitality of the pulp several millimeters below the surface. Our results are compared with published experimental data taken under similar conditions and are found to be in good general agreement. The results of this study do not contradict recently reported ablation of dentin with Nd:YAG laser radiation by contact fiber probes. In this case, the irradiation intensities are 3 to 4 orders of magnitude higher, so plasma formation and plasma shielding of the interior of the tooth are likely.
Scanning electron microscope observations of CO2 laser effects on dental enamel.
Studies of the effects of carbon dioxide (CO2) lasers on dental enamel have demonstrated that surface changes can be produced at low fluences (< 10 J/cm2) if wavelengths are used which are efficiently absorbed by the hard tissues. In this study, scanning electron microscopy (SEM) was used to characterize the wavelength dependence of surface changes in dental enamel after exposure to an extensive range of CO2 laser conditions. Bovine and human enamel were irradiated by a tunable, pulsed CO2 laser (9.3, 9.6, 10.3, 10.6 microns), with 5, 25, or 100 pulses, at absorbed fluences of 2, 5, 10, or 20 J/cm2, and pulse widths of 50, 100, 200, 500 microseconds. SEM micrographs revealed evidence of melting, crystal fusion, and exfoliation in a wavelength-dependent manner. Crystal fusion occurred at absorbed fluences as low as 5 J/cm2 per pulse at 9.3, 9.6, and 10.3 microns, in contrast to no crystal fusion at 10.6 microns (< or = 20 J/cm2). Longer pulses at constant fluence conditions decreased the extent of surface melting and crystal fusion. The total number of laser pulses delivered to the tissue did not significantly affect surface changes as long as a minimum of 5 to 10 pulses was used. Within the four easily accessible wavelengths of the CO2 laser, there are dramatic differences in the observed surface changes of dental hard tissue.
Selective increases in adrenal steroidogenic capacity during acute respiratory disease in infants.
To examine steroidogenic responses of the different zones of the adrenal cortex to acute disease we determined the basal and adrenocorticotropin (ACTH)-stimulated levels of cortisol, dehydroepiandrosterone (DHEAS) and aldosterone in 16 infants aged 1-4 months with acute bronchiolitis. Fourteen of the infants were retested after recovery. During illness the mean basal levels of cortisol and DHEAS were twice as high as the levels after recovery (370 vs 180 nmol/l and 2.7 vs 1.3 mumol/l, respectively). The mean peak ACTH-stimulated levels of cortisol and DHEAS during illness were 1.5- and 2.5-fold higher, respectively, than the levels found after recovery. Although aldosterone secretion was stimulated > or = 3-fold by ACTH, illness was not associated with any change in aldosterone secretory capacity. The basal and stimulated levels of both cortisol and DHEAS during illness and after recovery were correlated significantly. Thus, the relative steroidogenic capacities for these two steroids were characteristic of the individual infant and showed constancy over a period of at least several weeks. While the levels of cortisol and aldosterone were not dependent on the age of the infants, both the basal and stimulated levels of DHEAS correlated strongly with age. We conclude that during acute disease the steroidogenic capacity selectively increases in the zones that secrete cortisol and DHEAS (only in infants < 3 months) but not in the zona glomerulosa that secretes aldosterone. The DHEAS response may be related to its putative effects to enhance immune responses.
Serious complications of routine ritual circumcision in a neonate: hydro-ureteronephrosis, amputation of glans penis, and hyponatraemia.
A 13-day-old infant developed bilateral hydroureteronephrosis, severe hyponatraemia, hyperkalaemia, and acidosis, as a result of urethral damage following circumcision. The hydroureteronephrosis and biochemical abnormalities normalized after resolution of the penile injury. Conclusion. Infants with urinary retention following circumcision may develop hydro-ureteronephrosis and electrolyte disturbances. An awareness of the potential dangers of circumcision may help to limit its complications.
[Value of preoperative embolization of uterine fibroma: report of a multicenter series of 31 cases].
Pre-operative embolization of fibroids, an intervention radiology technique, significantly reduces the per and post-operative bleeding. It is an interesting alternative in the looking after of patients who have to undergo multiple myomectomies or the operation of voluminous fibroids responsible of large bleeding.
[Complication after an exploratory hysteroscopy: one more case].
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[David Ben-Gurion as a patient].
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[William Osler--clinician and teacher].
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[Aspirin in gravy--laughter is healthy].
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Benign cystic mesothelioma of the peritoneum: the occurrence of an adult entity in a child.
Benign cystic mesothelioma of the peritoneum is considered a disease of adulthood occurring predominantly in women. We report a case of benign cystic mesothelioma of the peritoneum in an 11-year-old boy. The innumerable cystic lesions that varied in size occupied the entire peritoneal cavity. He underwent two laparotomies in a period of 15 months during which a partial removal of the tumor was performed. Four years after the second operation the child is well and active, despite significant tumor tissue left behind after the first two operations. The management of this disease is discussed, and the importance of a conservative approach minimizing the number of laparotomies and avoiding radical surgical intervention especially in childhood is emphasized.
The first empirical demonstration of transference in psychotherapy.
This study investigates the similarity between patients' relationships with their therapists and patients' relationships with others in their life. We examined the in-session narratives about the therapist and compared them with the patient's general relationship pattern as determined by a previously tested method, the Core Conflictual Relationship Theme (CCRT) method. The source for both narratives and CCRT patterns were transcripts of therapy sessions from 35 consenting outpatients in a university clinic. We found significant similarity between the patterns of relationship with the therapist and with others. One aspect of the relationship pattern, the patient's response to the therapist and to others, was consistently similar. We offer objective evidence in support of an age-old and central tenet of psychodynamic therapy, the transference concept.
Diseases that mimic meningitis. Analysis of 650 lumbar punctures.
A retrospective review of charts for 650 children who had lumbar puncture for suspected meningitis was undertaken to determine the characteristics of patients with and without meningitis, identify other conditions suggesting meningitis, and evaluate the predictive value of signs and symptoms of meningitis. The incidence of positive lumbar punctures increased with patient age. Younger infants did not present with classical features of meningitis. Bulging fontanel, lethargy, and irritability were nonspecific symptoms. Vomiting and headache, although not specific, proved to be more sensitive indicators of meningeal infection. Most patients with meningitis (75%) had at least one sign of meningeal irritation, but so did 25% of patients without meningitis. Brudzinski's sign was not specific. In contrast, nuchal rigidity and Kernig's sign had high predictive value. Up to age five, the diseases most often suggesting meningitis were right-sided pneumonia, gastroenteritis, otitis, tonsillitis, exanthema subitum, and urinary tract infections. Of 171 patients with febrile convulsion, one (0.5%) had bacterial meningitis and four had aseptic meningitis.
Diseases that mimic meningitis.
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Development of severe Stevens-Johnson syndrome after administration of slow-release theophylline.
A 9-year-old boy developed Stevens-Johnson syndrome after taking slow-release theophylline for bronchial asthma. Multisystem symptoms were severe, especially in the skin and eyes. This is the first reported case of Stevens-Johnson syndrome after administration of theophylline (Theodur).