Time-associated variations of mitotic activity in livers of young rats

1959 ◽  
Vol 134 (3) ◽  
pp. 365-377 ◽  
Author(s):  
B. Jackson
Keyword(s):  
Mitotic Activity ◽  
Young Rats

Limited myogenic response to a single bout of weight-lifting exercise in old rats

2000 ◽  
Vol 278 (6) ◽  
pp. C1143-C1152 ◽  
Author(s):  
Tetsuro Tamaki ◽  
Shuichi Uchiyama ◽  
Yoshiyasu Uchiyama ◽  
Akira Akatsuka ◽  
Shinichi Yoshimura ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Western Blotting ◽  
Weight Lifting ◽  
Specific Gene ◽  
Myogenic Response ◽  
Acid Uptake ◽  
Rt Pcr ◽  
Young Rats ◽  
Single Bout ◽  
Old Rats

The purpose of the present study was to compare the myogenic response of hindlimb muscles in young (14–20 wk of age) and old (>120 wk of age) rats with a single exhaustive bout of heavy resistance weight lifting. [3H]thymidine and [14C]leucine labeling were monitored for up to 2 wk after the exercise bout to estimate serial changes in mitotic activity and the level of amino acid uptake and myosin synthesis. Histological, histochemical, and immunohistochemical [anti-5-bromo-2′-deoxyuridine and myogenic determination genes (MyoD)] analyses of whole muscles and analysis of muscle-specific gene expression (MyoD) using Western blotting and RT-PCR were performed. Old rats showed significant muscle atrophy and a lower exercise capacity than young rats. Exercise-induced muscle damage, as assessed in histological sections, and increases in serum creatine kinase activity were evident in both young and old exercised groups. Mitotic activity was increased in young, but not old, rats 2 days after exercise. There was a biphasic increase in [14C]leucine uptake during the 14 days postexercise (peaks at 1–4 and 10 days) in young rats: only the first peak was observed in old rats. There was a lower uptake of [14C]leucine in the myosin fraction and an impaired expression of MyoD at the protein (immunohistochemistry and Western blotting) and mRNA (RT-PCR) levels in old rats throughout the postexercise period. These results demonstrate a reduced reparative capability of muscle in response to a single bout of exercise in old compared with young rats.

An adrenocortical oncocytoma with unusual mitochondrial inclusions and cytoplasmic crystals

1994 ◽  
Vol 52 ◽  
pp. 250-251
Author(s):  
W.T. Gunning ◽  
G.D. Haselhuhn ◽  
E.R. Phillips ◽  
S.H. Selman
Keyword(s):  
Adrenal Gland ◽  
Salivary Glands ◽  
Mitotic Activity ◽  
Diagnostic Criteria ◽  
Vascular Invasion ◽  
Benign Neoplasm ◽  
Benign Tumors ◽  
Nuclear Morphology ◽  
Case Presentation ◽  
Microscopic Evidence

Within the last few years, adrenal cortical tumors with features concordant with the diagnostic criteria attributed to oncocytomas have been reported. To date, only nine reported cases exist in the literature. This report is the tenth case presentation of a presumptively benign neoplasm of the adrenal gland with a rare differentiation. Oncocytomas are well recognized benign tumors of the thyroid, parathyroid, and salivary glands and of the kidney. Other organs also give rise to these types of tumors, however with less frequency than the former sites. The characteristics generally used to classify a tumor as an oncocytoma include the following criteria: the tumor is 1) usually a solitary circumscribed mass with no gross nor microscopic evidence of metastasis (no tissue nor vascular invasion), 2) fairly bland in terms of mitotic activity and nuclear morphology, and 3) composed of large eosinophillic cells in which the cytoplasm is packed full of mitochondria (Figure 1).

On the Fibrinolytic System in Aged Rats, and Its Reactivity to Endotoxin and Cytokines

1992 ◽  
Vol 67 (06) ◽  
pp. 697-701 ◽  
Author(s):  
J J Emeis ◽  
A Brouwer ◽  
R J Barelds ◽  
M A Horan ◽  
S K Durham ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
High Dose ◽  
Base Line ◽  
Aged Rats ◽  
Tissue Type Plasminogen Activator ◽  
Young Rats ◽  
Type Plasminogen Activator

SummaryAged rats are more susceptible to endotoxin-induced effects, including microthrombosis and platelet aggregation, than are young rats. To investigate whether changes in the fibrinolytic system might be involved, we investigated the fibrinolytic activity in plasma euglobulin fractions and tissues (lung and heart) of young (6-months old) and aged (24-months old) rats under baseline conditions and after challenge with endotoxin. Aged rats had lower plasma levels of tissue-type plasminogen activator (t-PA) and of urokinase-type PA (u-PA) activity. PA inhibitor (PAI) activity was higher in the plasma of aged rats, as was t-PA activity in lung and heart.Rats were treated with either a low dose (1 μg/kg) or a high dose (10 mg/kg) of endotoxin. Both treatments induced a transient phase of increased blood fibrinolytic activity, as evidenced by higher levels of tissue-type plasminogen activator (t-PA) activity and decreased levels of PA inhibitor (PAI) activity. Over time, the fibrinolytic activity decreased, probably due to increased levels of PA inhibitor.Both the early increase in t-PA activity, and the subsequent increase in PAI activity, were more pronounced in the aged rats, as compared with the younger rats, after the high dose of endotoxin. The aged rats also responded to an injection of interleukin-1β or tumor necrosis factor-α with a larger increase of PAI activity than did the younger rats.Together the data suggest that, compared to young rats, aged rats have a decreased base-line plasma fibrinolytic activity, while their fibrinolytic system is more responsive to challenge by endotoxin and cytokines.

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