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Biomedical subjects

I Friedman

Publications and source records attributed to I Friedman.

At least 19 recordsLinked to original sources
PubMed1992

Prolonged conductive hearing loss in rat pups causes shorter brainstem transmission time.

A carefully controlled study was conducted in rats to determine whether a reversible conductive hearing loss during the neonatal period could induce changes in central conduction and thereby perhaps contribute to an understanding of learning problems seen in children following conductive hearing loss in infancy. Ear plugs were inserted from post-natal day 9 in rat pups and auditory nerve brainstem evoked responses were recorded in the presence of ear plugs and following their removal on post-natal day 23. The I-IV interpeak latency (brainstem transmission time) was significantly shorter in the experimental rats several days after plug removal (day 28) compared to untreated control rats. This difference was not related to residual conductive loss, nor to different body weights and was present even in response to equal sensation level stimuli, and was not present in adult rats with similarly induced conductive hearing losses. It seems therefore that conductive hearing loss in the young animal (critical period?) can induce changes in central auditory conduction and may be related to the findings of smaller brainstem auditory neurons in sound deprived animals. These results have implications for neonatal hearing loss in humans.

Animals↗
PubMed1992

Initial experience with laparoscopic cholecystectomy at the Beth Israel Medical Center.

Laparoscopic cholecystectomy has changed the treatment of symptomatic gallstones. We present an initial experience with this technique. From March 1990 to March 1991, there were 250 patients who were studied. There were 182 females and 68 males, with most classified as American Society of Anesthesiology Index Class I or II. All procedures were done using electrocautery. There was a definite learning curve for the procedure as evidenced by the duration of the operation. The mean time to perform the procedure was 112 minutes for the first 50 patients and 79 minutes for the last 50 patients. We converted 12 percent of the procedures to an open cholecystectomy for a variety of reasons, the most common being inflammation and adhesions in the triangle of Calot. However, we only had a 4 percent conversion rate in the last 50 patients. There were nine serious complications, with no deaths. The most frequent was a bile leak from the cystic duct stump. Other complications included a pneumothorax, requiring chest tube drainage and an unobserved carcinoma of the stomach. There were no injuries to the common bile duct. The results of our current experience confirm the safety and efficacy of laparoscopic cholecystectomy for the treatment of symptomatic gallstones. The use of electrocautery is safe during laparoscopy and the need for a laser is optional. Laparoscopic cholecystectomy will continue to evolve as more experience is gained and new instruments are introduced.

Adult↗
PubMed1991

Auditory brainstem response (ABR) latency shifts in animal models of various types of conductive and sensori-neural hearing losses.

Clinical ABR studies in patients with peripheral hearing loss have led to conflicting results, some reporting increases in brainstem transmission time (BTT), some decreases, and others no change. In order to study this in a carefully controlled fashion, various types of peripheral hearing losses were induced in experimental animals: conductive hearing loss by occluding auditory meatus (rats) (CHL), noise induced temporary sensori-neural hearing loss (rats) (NI-SNHL), stimulus intensity attenuation (rats), (Atten.), and controlled hypoxemia induced temporary sensori-neural hearing loss (cats) (HI-SNHL). ABR latencies and thresholds were determined in each animal before (control) and during the induced hearing loss (experimental) states. The data in each group in each state were analyzed by calculating group average values for latency of waves 1 and 4, their interpeak latency (BTT), paired t-tests for changes between the control and experimental states and linear regression analysis of latency changes on threshold shift. In each group, there were small decreases in BTT in the experimental state (not significant in the CHL group only). This was caused by the prolongation of latency of wave 1 to a greater extent than that of wave 4. These changes were smaller than the standard deviation of the BTT in the control state. Therefore, in attempting to apply these results to the human clinical situation, these small decreases in BTT would not be considered abnormal. Possible mechanisms of these BTT changes are considered.

Animals↗
PubMed1980

Interactions of cardiac glycosides with cultured cardiac cells. II. Biochemical and electron microscopic studies on the effects of ouabain on muscle and non-muscle cells.

Electron microscopic and biochemical studies revealed a salient difference in the response to toxic doses of ouabain by cultured cardiac muscle and non-muscle cells from neonatal rats. Progressive cellular injury in myocytes incubated with 1 . 10(-4)--1 . 10(-3) M ouabain ultimately leads to swelling and necrosis. The morphological damage in myocytes was accompanied by a drastic decrease in 14CO2 formation from 14C-labeled stearate or acetate but not glucose. Neither morphological nor biochemical impairments were observed in non-muscle cells. The interaction between ouabain and the cultured cells, using therapeutic doses of ouabain (i.e., less than 1 . 10(-7) M), was characterized. Two binding sites were described in both classes of cells, one site is a saturable K+-sensitive site whereas the other is non-saturable and K+-insensitive. The complexes formed between the sarcolemma receptor(s) and ouabain, at low concentrations of the drug (e.g., 7.52 . 10(-9) M), had Kd values of 8.9 . 10(-8) and 2.3 . 10(-8) M for muscle and non-muscle cells, respectively. The formation and dissociation of the complexes were affected by temperature and potassium ions.

Animals↗
PubMed1977

Retrorectal abscess with neurologic involvement of the lower extremities: report of a case.

A case of retrorectal abscess with neurologic involvement of both lower extremities is presented. The authors believe that an adequate description of this entity is necessary for the clinician, insofar as rectal suppurations rarely cause neurologic symptoms. The clinician must be alert for the possibility of the presence of various presacral tumors, whose treatment and prognosis present much graver problems.

Abscess↗