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H Sternberg

Publications and source records attributed to H Sternberg.

11 recordsLinked to original sources
PubMed1990

Family of human neuronal external surface epitopes defined by Torpedo monoclonal antibodies.

We are employing a library of monoclonal antibodies (MAbs) that were made to Torpedo cholinergic synaptosomes to identify conserved, physiologically vital epitopes of the neuronal surface. Our particular interest is in those epitopes that are present on some but not all neurons. In the present study we screened this library on different cell lines, the neuronal cell lines PC12, NG108, MC-IXC, and SY5Y, and the endocrine cell lines GH-3 and HIT. Of these cell lines, only SY5Y cells bind MAbs that define neuronal surface subsets. Utilizing its parent cell line, SK-N-SH, we verified that six MAbs, Tor 25, Tor 103, Tor 190, Tor 201, Tor 219, and Tor 233, bind the external neuronal surface. The cytolocalization of all six MAbs is very similar: the membrane of the cell body and its processes are finely outlined in a punctate distribution. Western blot analyses of Torpedo electric organ homogenates, a highly enriched source of antigenic material, revealed that each MAb identifies multiple polypeptides, two of which have the relative mobilities of 180 kD and 67 kD. In a screen of peripheral nerves from cases of amyotrophic lateral sclerosis (ALS), we found that all these MAbs revealed surface alterations; some displayed a decrease in binding, while others displayed an increase. The combined data provide evidence that these epitopes belong to an important, complex family of polypeptides of the external neuronal surface.

Amyotrophic Lateral Sclerosis↗
PubMed1989

Doxorubicin affects tau protein metabolism in human neuroblastoma cells.

The microtubule associated protein called tau, found primarily in neurons, was detected in a human neuroblastoma cell line, LAN-5. Cells treated with retinoic acid (2.0 x 10(-5) M) differentiate and acquire processes similar to neurons. Differentiated and logarithmically growing undifferentiated cells were exposed to varying doses of doxorubicin (an anthracycline chemotherapeutic antibiotic). While doxorubicin was lethal to many undifferentiated dividing cells, it was not as damaging to differentiated cells. After 2 to 4 days of doxorubicin treatment, the cells were harvested, the protein concentration determined and SDS-PAGE performed. Proteins were blotted onto nitrocellulose paper and immunostained with either a rabbit antiserum or mouse monoclonal antibody to tau. Undifferentiated LAN-5 cells treated with 4.0 x 10(-8) M doxorubicin for 4 days and cells treated with 8.0 x 10(-8) M doxorubicin for 2 days displayed a distinct lower band (just below the 50 kd marker) that was either absent or very faint in untreated controls.

Antibodies, Monoclonal↗
PubMed1987

A human teratocarcinoma which expresses a rare neuronal cell surface antigen.

A molecular characterization of the events at the cell surface of neurons is pivotal for our understanding of how the nervous system is formed and maintained. This study of cell surface events in the human nervous system may be crucial to the study of human neurological maladies. NTERA-2 is a human teratocarcinoma which is unique amongst the teratocarcinomas for its ability to express many neurons. Tested for the binding of a monoclonal antibody Tor 23, which recognizes a surface antigen on rare and specific neurons, cultures of NTERA-2 cells contained cells with a neuronal morphology which bound the monoclonal antibody Tor 23 on their surface. The data indicate that Tor 23 antigen is a cell surface molecule with the same or very similar properties in rays, rats, and humans. The NTERA-2 cells are thus capable of expressing highly differentiated neuronal cell surface phenotypes and promise to be a powerful model system for the study of cell surface events of the human nervous system in vitro.

Acetylcholinesterase↗
PubMed1985

Effects of dietary choline on memory and brain chemistry in aged mice.

The purpose of this study was to investigate in more detail the characteristics of the age-related extension of the retrograde amnesia gradient previously demonstrated in a passive avoidance task [6]. In Experiment 1, it was found that while 2-3 month old mice were susceptible to the amnesic effects of anisomycin (ANI) only when given prior to 15 min post-training, memory of 14-16 month old mice was susceptible to disruption when ANI was given as late as 20 min post-training, and retention of 17-20 month old mice was impaired when ANI was injected even as late as 30 min after training. Experiment 2 examined whether the age-related change in susceptibility to the effects of ANI could be ameliorated by chronic pretreatment with a choline-enriched diet. Results showed that ANI injected 20 min after training did not induce amnesia in choline treated mice (14.5 month old), but did induce amnesia when injected 15 min post training. Subsequent assay of choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) activity showed that choline treatment significantly reduced ChAT activity but did not affect TH activity. It appears that dietary choline treatment can render new long-term memories less susceptible to disruption following training.

Aging↗
PubMed1979

Cellular replication and aging.

Controversy exists concerning the effect of aging on replicating cell systems. This review summarizes a number of studies which indicate that both in vivo and in vitro, cell replication is significantly altered during aging. In vitro, studies of both human lymphocytes and fibroblasts indicated that a number of replication kinetic parameters are influenced by the age of the cell donor. In vivo, the application of the bromodeoxyuridine-(BrdU)-differential chromatid staining techniques to the analysis of cellular replication kinetics has permitted us to demonstrate that cellular replication is also significantly diminished with aging in mouse and rat cell populations. Therefore, both in vivo and in vitro in human as well as rodent cell populations, the rates of cellular replication are significantly decreased with cellular aging.

Aging↗
PubMed1977

In vivo analysis of cellular replication.

The number of previous cell replications that a metaphase cell has undergone in the presence of BrdUrd can be determined by the differential fluorescent patterns of metaphse chromosomes stained with Hoechst dye 33258. To examine if this technique could be applied to analyzing cell cycle kinetics in vivo, we infused Wistar rats with BrdUrd for 7.5-33 hr at concentrations of the nucleotide analog that did not inhibit cellular replication. Examination of the frequency of one, two, and three or more replication cycle cells as a function of BrdUrd infusion time indicates that cell replication times for rat bone marrow cells are relatively homogeneous. Analysis of this data with a computer simulation model produced a mean cell cycle duration of 9.2 hr, which is compatible with the fastest times obtained with radioisotope studies. These results support the potential of nonradioisotope analysis of cell replication in vivo.

Animals↗
PubMed1976

The coupling effects of some thiol and other sulfur-containing compounds on the circadian rhythm of cell division in photosynthetic mutants of Euglena.

Previous work has demonstrated a persisting, free-running, circadian rhythm of cell division in the P4ZUL photosynthetic mutant of the alga Euglena gracilis Klebs (Strain Z) Pringsheim grown organotrophically in continuous light or darkness at 19 degrees C following prior synchronization by a repetitive LD:10,14 light cycle. A similar circadian rhythmicity has been recently discovered in the W6ZHL heat-bleached and the Y9ZNalL naladixic acid-induced mutants of Euglena grown under comparable conditions. Over extended timespans, however, these mutants appear to gradually lose first their ability to display persisting overt rhythms, and then even their capability of being entrained by imposed LD cycles. These properties can be restored by the addition of certain sulfur-containing compounds to the medium including cysteine, methionine, dithiothreital, sodium monosulfide, sodium sulfite, and sodium thiosulfate, as well as thioglycolic [mercaptoacetic] acid. The implications of these findings toward biological clock mechanisms are discussed: It appears that some sort of coupling process is operating as opposed to the initiation of an underlying oscillation.

Amino Acids, Sulfur↗
PubMed1976

Corneal endothelial damage associated with phacoemulsification.

Twenty-one cats underwent standard Kelman phacoemulsification procedures in their right eyes. The left eyes of the same amimals underwent a planned extracapsular cataract extraction or irrigation and aspiration for 15 minutes using the Kelman phacoemulsification unit. The corneal endothelium was evaluated at various times postoperatively using a stain for endothelial cell viability and scanning electron microscopy. The results suggested that the irrigation procedure alone is deleterious to the cat endothelium as is the rubbing of nuclear material against the endothelial cells. These two procedures caused additonal damage when combined in a routine phacoemulsification procedure.

Animals↗