PubMed Health⌕ Search

Biomedical subjects

J Alzofon

Publications and source records attributed to J Alzofon.

5 recordsLinked to original sources
PubMed1990

Ultrastructural evidence that insoluble microtubules are components of the neurofibrillary tangle.

The ultrastructure of Alzheimer's neurofibrillary tangles is heterogeneous and includes abnormal paired helical filaments (PHF) and various other insoluble structures. Insoluble non-PHF components isolated from neurofibrillary tangles were examined by electron microscopy. Comparison of these fractions with normal assembled neurofilaments and normal brain microtubules revealed scattered profiles which were morphologically (not chemically) identical to structures present in the microtubule, but not in the neurofilament preparations. These results support the notion that insoluble microtubules contribute to the make up of the neurofibrillary tangle. Based on these findings, preliminary experiments were conducted which suggest that non-enzymatic glycosylation may be a pathway leading to insolubility of the microtubules.

Aged↗
PubMed1988

Colloid (hyaline) inclusion bodies in the central nervous system: their presence in the substantia nigra is diagnostic of Parkinson's disease.

Intracytoplasmic "colloid" inclusions have been described within neurons of several discrete central nervous system nuclei in a variety of entities. Although they lack specificity for any particular disease, they are believed to represent one of the morphologic changes of neuronal aging. Because premature aging of the substantia nigra has been one of the claimed mechanisms occurring in Parkinson's disease, the prevalence of colloid inclusions was studied within the substantia nigra in 15 patients with Parkinson's disease, 15 age-matched controls, 50 "normal" individuals, 10 patients with dementia of Alzheimer's type, and two patients with amyotrophic lateral sclerosis. Colloid bodies were found in the substantia nigra of all patients with Parkinson's disease and were virtually absent in the other populations. Histochemical and ultrastructural analyses showed that colloid bodies differ from early and mature Lewy bodies. They may represent the "pale" inclusions rarely mentioned in the literature and often mistaken for early Lewy bodies. "Colloid" bodies in the substantia nigra are diagnostic of Parkinson's disease. These findings support the theory of "premature" aging of the substantia nigra in this disease.

Adult↗
PubMed1987

Uptake of sidestream smoke by Syrian golden hamsters.

An inhalation bioassay with Syrian golden hamsters is being conducted to evaluate the toxic and carcinogenic potential of cigarette sidestream smoke (SS) relative to mainstream smoke (MS). A Hamburg II smoking machine is used to deliver MS by nose-only exposure to hamsters and a modification allows for the simultaneous collection of SS for whole-body delivery to a different rack of animals. The tolerated dose of SS was determined by varying the air/smoke dilutions drawn through the animal restrainers. Preliminary data indicated that 20% carboxyhemoglobin (COHb) could be obtained in SS-exposed animals without fatality. Optimum exposure levels were determined. Monthly measurements of COHb, nicotine and cotinine indicate that the SS-exposed animals are absorbing slightly higher amounts of these smoke constituents than the MS-exposed hamsters. Tumor incidence and carcinogenicity data are being collected through complete necropsy and histology protocols and uptake data continue to be collected. These studies should help elucidate the carcinogenic potential of SS which has been suggested from its composition and from recent epidemiological data of cancer incidence in non-smokers.

Animals↗