Comparison of hepatic protein synthesis in vivo versus in vitro in the tumor-bearing rat

1. The intraperitoneal injection of N-methyl-N-nitrosourea (100mg/kg) caused a partial inhibition of protein synthesis in several organs of the rat, the maximum effect occurring after 2–3h. 2. In the liver the inhibition of protein synthesis was paralleled by a marked disaggregation of polyribosomes and an increase in ribosome monomers and ribosomal subunits. No significant breakdown of polyribosomes was found in adult rat brains although N-methyl-N-nitrosourea inhibited cerebral and hepatic protein synthesis to a similar extent. In weanling rats N-methyl-N-nitrosourea caused a shift in the cerebral polyribosome profile similar to but less marked than that in rat liver. 3. Reaction of polyribosomal RNA with N-[14C]methyl-N-nitrosourea in vitro did not lead to a disaggregation of polyribosomes although the amounts of 7-methylguanine produced were up to twenty times higher than those found after administration of sublethal doses in vivo. 4. It was concluded that changes in the polyribosome profile induced by N-methyl-N-nitrosourea may reflect the mechanism of inhibition of protein synthesis rather than being a direct consequence of the methylation of polyribosomal mRNA.

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Synthesis of M Protein by Mouse Myeloma Tumor: Correlation of In Vitro and In Vivo Methods

Blood ◽

10.1182/blood.v18.2.176.176 ◽

1961 ◽

Vol 18 (2) ◽

pp. 176-181

Author(s):

WAYNE E. TRUAX ◽

JUANITA P. BRAY

Keyword(s):

Multiple Myeloma ◽

Protein Synthesis ◽

M Protein ◽

Tumor Bearing ◽

Myeloma Proteins ◽

In Vitro Incubation ◽

Human Multiple Myeloma ◽

Mouse Myeloma

Abstract 1. In vitro incubation of Potter-Pilgrim No. 5563 and No. 5647 mouse myeloma tumors with tritiated-d,l-leucine produced demonstrable radioactivity in the respective myeloma proteins. 2. In vivo inoculation of H3-d,l-leucine in tumor bearing animals showed similar incorporation and in addition showed incorporation of radioactivity into albumin and alpha globulin. 3. It is suggested that the in vitro studies better serve to identify the isolated tissue function in protein synthesis. 4. Mouse myeloma studies confirm previous results in human multiple myeloma and indicate that in vitro incubation of protein producing tissues with H3-d,l-leucine can demonstrate protein synthesis.

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Comparison of cycloheximide effect on hepatic protein synthesis at the microsomal level in vivo and in vitro

Biochemical Pharmacology ◽

10.1016/0006-2952(67)90325-5 ◽

1967 ◽

Vol 16 (10) ◽

pp. 2055-2059 ◽

Cited By ~ 10

Author(s):

W.R. Jondorf ◽

D. Grünberger

Keyword(s):

Protein Synthesis ◽

Hepatic Protein Synthesis

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Certain aspects of cholesterol metabolism and hepatic protein synthesis in the rat

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1964.207.6.1287 ◽

1964 ◽

Vol 207 (6) ◽

pp. 1287-1294 ◽

Cited By ~ 6

Author(s):

Shiro Saito ◽

Louis Charles Fillios

Keyword(s):

Protein Synthesis ◽

Cholesterol Metabolism ◽

Dietary Treatment ◽

High Serum ◽

Liver Protein ◽

High Serum Cholesterol ◽

Cholesterol Levels ◽

Hepatic Protein Synthesis

Hepatic protein synthesis was studied in rats fed a hypercholesteremic diet, containing cholesterol and cholic acid, and high in fat. If such a diet was fed for periods of at least 4 weeks a lowered capacity of amino acid incorporation into liver protein in vivo and in vitro was observed. The animals selected were rats which had been previously characterized by such a dietary assay as being neither refractory nor susceptible to induction of high serum cholesterol levels. When "hypo-responders" (i.e., rats which are relatively refractory to hypercholesteremia) were compared to "hyper-responders" significant differences in protein synthesis in vivo were observed after only 2 weeks of dietary treatment; the capacity for incorporation of amino acids in the livers of hyper-responders was significantly lower than that in the hypo-responders. Several studies were also carried out in vitro including an attempt to determine which intracellular components of the liver may be affected; it appears that the defect(s) is primarily related to the endoplasmic reticulum. Thus, diet may act as the modus operandi for revealing any purported inherent defect(s).

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EXTH-71. CYTOSTATIC HYPOTHERMIA FOR GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.425 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii102-ii103

Author(s):

Syed Faaiz Enam ◽

Jianxi Huang ◽

Cem Kilic ◽

Connor Tribble ◽

Martha Betancur ◽

...

Keyword(s):

Tumor Recurrence ◽

Progression Free Survival ◽

Rodent Model ◽

Behavioral Alterations ◽

Free Survival ◽

Tumor Bearing ◽

Car T ◽

The Brain

Abstract As a cancer therapy, hypothermia has been used at sub-zero temperatures to cryosurgically ablate tumors. However, these temperatures can indiscriminately damage both tumorous and healthy cells. Additionally, strategies designed to kill tumor typically accelerate their evolution and recurrence can be inevitable in cancers such as glioblastoma (GBM). To bypass these limitations, here we studied the use of hypothermia as a cytostatic tool against cancer and deployed it against an aggressive rodent model of GBM. To identify the minimal dosage of ‘cytostatic hypothermia’, we cultured at least 4 GBM lines at 4 continuous or intermittent degrees of hypothermia and evaluated their growth rates through a custom imaging-based assay. This revealed cell-specific sensitivities to hypothermia. Subsequently, we examined the effects of cytostatic hypothermia on these cells by a cursory study of their cell-cycle, energy metabolism, and protein synthesis. Next, we investigated the use of cytostatic hypothermia as an adjuvant to chemotherapy and CAR T immunotherapy. Our studies demonstrated that cytostatic hypothermia did not interfere with Temozolomide in vitro and may have been synergistic against at least 1 GBM line. Interestingly, we also demonstrated that CAR T immunotherapy can function under cytostatic hypothermia. To assess the efficacy of hypothermia in vivo, we report the design of an implantable device to focally administer cytostatic hypothermia in an aggressive rodent model of F98 GBM. Cytostatic hypothermia significantly doubled the median survival of tumor-bearing rats with no obvious signs of distress. The absence of gross behavioral alterations is in concurrence with literature suggesting the brain is naturally resilient to focal hypothermia. Based on these findings, we anticipate that focally administered cytostatic hypothermia alone has the potential to delay tumor recurrence or increase progression-free survival in patients. Additionally, it could also provide more time to evaluate concomitant, curative cytotoxic treatments.

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Effect of microbial isolates on microbial yield estimation in RUSITEC system

BSAP Occasional Publication ◽

10.1017/s0263967x0003295x ◽

1998 ◽

Vol 22 ◽

pp. 306-308

Author(s):

M. D. Carro ◽

E. L. Miller

Keyword(s):

Protein Synthesis ◽

Liquid Phase ◽

Solid Phase ◽

Liquid Fraction ◽

Microbial Protein ◽

Microbial Protein Synthesis ◽

Continuous Culture System ◽

The One

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).

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