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Biomedical subjects

M Erlich

Publications and source records attributed to M Erlich.

6 recordsLinked to original sources
PubMed1997

Collagen shortening. An experimental approach with heat.

Decreasing joint laxity is a clinical goal of ligament reconstructions. This in vitro study examined the structural and histologic effects of heat shrinkage of human collagen. Two preliminary studies were performed to assess the effect of heat on fresh frozen human tendons obtained from a local tissue bank. As heat was applied to tissue in a saline solution, the percent shrinkage was plotted against temperature. A second study used a freebeam Nd:YAG laser to maximally shrink patellar tendons measuring percent shrinkage versus energy applied. Finally, the effects of 10% shrinkage of fresh frozen human patellar tendons were analyzed mechanically and histologically. Consistent tendon shrinkage curves were found with increasing temperatures in a saline solution. A sharp increase in shrinkage to approximately 70% of resting length was noted around 70 degrees C. Tendon shrinkage by laser induced heat was precise and dose related. Tensile testing of the tendons shortened 10% of their resting length showed a decrease in load to failure to approximately 1/3 compared with that of historical control specimens. Histologic sections showed a well demarcated site of diffuse denaturation and degeneration of collagenous elements. Normal collagen was present adjacent to these thermal changes. These experiments showed that collagen tissue can be shortened precisely by the application of heat. Future studies need to examine the in vivo biologic response of shortened collagen tissue with time, especially recollagenization, restoration of length, and the long term biomechanical effects.

Biomechanical Phenomena↗
PubMed1988

Optic nerve regeneration--new aspects.

Injury to the optic nerve and its environment provokes a process of degeneration that leads to a degenerative process resulting in an irreversible loss of visual function. We succeeded in stimulating regeneration in injured optic nerves of adult rabbits. The stimulus to regeneration was achieved by implanting in injured optic nerves of adult rabbits substances originating from growing (regenerating) optic nerves of fish or developing optic nerves of neonatal rabbits, and by delaying the degenerative process by irradiating the injured optic nerve with a low energy laser. The effect was manifested by abundant growth of new fibers across the injury site and by other manifestation of regeneration characteristics.

Animals↗
PubMed1987

Effects of low-energy He-Ne laser irradiation on posttraumatic degeneration of adult rabbit optic nerve.

Axons of the mammalian peripheral and central nervous systems degenerate after nerve injury. We have recently found that He-Ne laser irradiation may prevent some of the consequences of the injury in peripheral nerves of mammals. In the present study, the efficacy of the laser in treating injured neurons of the mammalian CNS was tested. Optic nerves of adult rabbits were exposed daily for 8-14 days to He-Ne laser irradiation (14 min, 15 mW) through the overlying muscles and skin. As a result of this treatment, the injured nerves maintained their histological integrity, which is invariably lost in injured mammalian CNS neurons.

Animals↗
PubMed1975

Some additional observations relating to the mechanism of trypan blue induced teratogenesis.

The mechanism and site of teratogenic action of trypan blue on mammalian embryos was reinvestigated. The experiments to be presented include (1) an analysis of the effect of trypan blue treatment on the morphology of the early mouse egg cylinder, (2) a demonstration of the effect of dye treatment on the enzyme acid phosphatase of yolk sac epithelium using histochemical procedures. Results obtained from these experiments indicate that trypan blue injected into mothers on day 7 of gestational age leads, within 12 to 24 hours after treatment, to dramatic abnormalities in 90-95% of egg cylinders examined. The frequency of gross malformations obtained by this treatment is considerably less when litters are examined at later stages of gestation. Acid phosphatase activity in yolk sac epithelium is depressed by the dye treatment, but there is no difference between enzymatically depressed yolk sacs of malformed embryos and yolk sacs surrounding normally appearing litter mates both obtained from trypan blue treated mothers. The hypothesis that trypan blue may exert its teratogenic effect by the direct exposure of egg cylinder stages to the dye, and that some of the egg cylinders affected may subsequently repair, is recommended for further testing.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

[Panic attacks and 24-hour ambulatory EEG monitoring].

A 24 hour ambulatory EEG study performed in a population of 300 non epileptic outpatients with an anxious and depressive pathology revealed a high prevalence of abnormalities in subjects referred with panic disorder. Two groups of 150 medication-free patients each have been selected on the base of DSM-III-R = one with panic attacks (PA), the other with depressive patients without paroxystic anxiety (DS). The results showed respectively = in the PA group 63.2% abnormal, 19.7% normal and 17.1% dubious records. In the DS group = 74.5% normal, 18.3% abnormal and 7.2% dubious records. Epileptiform abnormalities were 4 times more frequent in the PA group (80%) than in the DS group (20%). Two nycthemeral peaks were found (5-8 pm and 3 hours after awakening). MRI has permitted the discovery of abnormal cerebral images in 3 patients of the PA group (cyst of the insula, temporal and parietal cryptic angiomas, sequelae of a parietal vasculo-cerebral stroke) frequency appearing to be clearly superior to the one resulting from recent epidemiologic data. The subclinical character of 2/3 of these abnormalities refers beyond epilepsy to their signification in the field of emotive and intellectual disturbances. The paradoxal efficiency of tricyclic drugs in panic disorder, sets the problem of their eventual antiepileptic action at low doses. If recent data on standard EEG in panic disorder is available, we did not find any similar study to ours in order to confront our results.

Adult↗