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Biomedical subjects

L Finkel

Publications and source records attributed to L Finkel.

8 recordsLinked to original sources
PubMed2002

Nicotinic receptor modulation: advantages for successful Alzheimer's disease therapy.

Galantamine is a modest acetylcholinesterase inhibitor (AChEI) that is also an allosteric potentiating ligand (APL) of nicotinic acetylcholine receptors (nAChRs). In this report, these two effects are shown to be dependent upon each other using a realistic computer model of the cholinergic synaptic cleft. The model is based upon realistic estimates of the anatomy of a neuronal synapse, the kinetic states of pre- and postsynaptic nAChRs, and the acetylcholinesterase enzyme. The number of open postsynaptic nAChRs per action potential is a measure of cholinergic neurotransmission. Using mathematical equations and published data, the effect of the AChEI and APL actions of galantamine is quantitatively described and compared to the effects of pure AChEIs. The model shows that galantamine--compared to similar concentrations of pure AChEIs--is able to compensate for its somewhat modest effect on the cholinesterase enzyme with its allosteric modulatory effects that include the additional benefit of a lower degree of receptor desensitization.

Aged↗
PubMed1998

Gap-filling and end-of-sentence effects in real-time language processing: implications for modeling sentence comprehension in aphasia.

We present an on-line study showing different sources of lexical activation during sentence comprehension, distinguishing in this respect between reflexive syntactic and less temporarily constrained nonsyntactic sources. Specifically, we show that both the syntactic process of gap filling and a nonsyntactic end-of-sentence effect can be measurable in real time and can be temporally separated. The distinction between activation sources provides a new perspective on real-time sentence comprehension in aphasia and accounts for the disparate results reported in the literature.

Aged↗
PubMed1998

The neurology of empty categories aphasics' failure to detect ungrammaticality.

A direct investigation into the grammatical abilities of Broca's and Wernicke's aphasics sought to obtain critical evidence for a revised model of the functional neuroanatomy of language. We examined aphasics' ability to make grammaticality judgments on a set of theoretically selected, highly complex syntactic structures that involve, most prominently, fine violations of constraints on syntactic movement. Although both groups have been thought to possess intact abilities in this domain, we discovered severe deficits; Broca's and Wernicke's aphasics (whose performances differed) exhibited clear, delineated, and grammatically characterizable deficits - they follow from the Trace-Deletion Hypothesis, which is motivated by independent comprehension results. These conclusions have both linguistic and neurological implications; Linguistically, they show that the aphasic deficit interacts with more than one module of the grammar. Namely, it manifests not only when the thematic module is called for in interpretive tasks but also when constraints on syntactic movement are tapped in a study of judgment. Neurologically, the results support a view of receptive grammatical mechanisms in the left cortex, which is functionally more restrictive than currently assumed; neuroanatomically, however, it is more distributed.

Aged↗
PubMed1992

Differential modulation of transforming growth factor-beta 1 expression and mucin deposition by retinoic acid and sodium lauryl sulfate in human skin.

Immunohistochemical staining of skin sections with two polyclonal antibodies (anti-CC 1-30 and anti-LC 1-30), specific for transforming growth factor-beta 1, revealed increased extracellular and decreased intracellular expression of transforming growth factor-beta 1 in retinoic acid-treated, compared to vehicle-treated, skin. Transforming growth factor-beta 1 staining, with both antibodies, was most marked in the upper layers of the epidermis, although dermal staining was also evident. The modulation of transforming growth factor-beta 1 expression by retinoic acid occurred in the absence of any change in its mRNA level. Transforming growth factor-beta 1 protein, as detected by rabbit polyclonal antibody (anti-LC 50-75) and mRNA, were only minimally detected in either retinoic acid- or vehicle-treated skin. Similar changes in TGF-beta 1 and TGF-beta 2 immunoreactivity and mRNA levels, as observed in retinoic acid-treated skin, were observed in skin following topical application of the irritant sodium lauryl sulfate, indicating that the alterations induced by retinoic acid were not specific. In contrast, mucin deposition, which is induced by transforming growth factor-beta, was elevated in retinoic acid-treated but not sodium lauryl sulfate-treated skin. Cultured adult human keratinocytes also expressed predominantly transforming growth factor-beta 1 protein, as measured by ELISA, and mRNA. Treatment of keratinocytes with retinoic acid resulted in a 50% induction of transforming growth factor-beta 1 protein, without any detectable change in transforming growth factor-beta 2. These data demonstrate disassociation of modulation of transforming growth factor-beta 1 expression and mucin deposition by retinoic acid and sodium lauryl sulfate in human skin in vivo. Whereas alterations in transforming growth factor-beta 1 expression were observed in both retinoic acid- and sodium lauryl sulfate-treated skin, accumulation of mucin was specific to retinoic acid-treated skin.

Adult↗
PubMed1988

Fatal complications related to diagnostic barium enema.

Thousands of barium enemas are performed in the United States each year without incident. Occasionally complications arise, only a few of which are fatal. Perforation is the most frequent serious complication of this procedure. Two instances of fatal perforation, one colonic and the other vaginal, are described, and the relevant literature is reviewed.

Aged↗
PubMed1986

Endometrial cyst of the liver.

A 21-yr-old woman with a history of epigastric pain and a right upper quadrant mass was found to have a large parenchymal hepatic cyst on CT scan. The cyst was removed at surgery and found to be lined by ectopic endometrial tissue. This is, to our knowledge, the first recorded instance of endometriosis of the liver. The clinicopathological features of this patient and the possible pathogenesis of her most unusual hepatic lesion are discussed.

Adult↗