scholarly journals Histomorphometric identification of carbonic anhydrase in fetal rat bone embedded in glycolmethacrylate.

1987 ◽  
Vol 35 (2) ◽  
pp. 245-250 ◽  
Author(s):  
P J Marie ◽  
M Hott
Keyword(s):  
Acid Phosphatase ◽  
Carbonic Anhydrase ◽  
Bone Tissue ◽  
Specific Inhibitor ◽  
Slight Modification ◽  
Histochemical Staining ◽  
Histochemical Reaction ◽  
Low Concentrations ◽  
Fetal Rat ◽  
Rat Bone

Carbonic anhydrase was identified in bone-resorbing cells present in sections of fetal rat femur embedded in glycolmethacrylate. Using a slight modification of the Hansson's histochemical method, we demonstrated that most chondroclasts (91.8-95.4%) and osteoclasts (95.1-96.3%) display a positive histochemical reaction for carbonic anhydrase. This staining was consistently inhibited in the presence of very low concentrations (10(-6), 10(-7) M) of the specific inhibitor acetazolamide. The number of chondroclasts reacting for carbonic anhydrase was identical to the number of acid phosphatase-stained chondroclasts determined on adjacent sections. A large majority of osteoclasts (96.3%) stained for carbonic anhydrase and for acid phosphatase (97.2%), with more osteoclasts reacting for the latter enzyme than the former (76.8 +/- 8.5 (SD) vs 85.3 +/- 9.2 cells/mm2 of endosteal bone; p less than 0.01). The observation that acetazolamide at a concentration as low as 10(-7) M inhibited Hansson's reaction, together with our histomorphometric results, validates the use of histochemical staining for carbonic anhydrase to evaluate activity of bone-resorbing cells identified in plastic-embedded fetal bone tissue.

Platelet-Bound Prekallikrein Promotes Pro-Urokinase-Induced Clot Lysis: A Mechanism for Targeting the Factor XII Dependent Intrinsic Pathway of Fibrinolysis

1994 ◽  
Vol 71 (03) ◽  
pp. 347-352 ◽  
Author(s):  
Jean-Pierre Loza ◽  
Victor Gurewich ◽  
Michael Johnstone ◽  
Ralph Pannell
Keyword(s):  
Platelet Rich Plasma ◽  
Specific Inhibitor ◽  
Specific Effect ◽  
Clot Lysis ◽  
Factor Xii ◽  
Intrinsic Pathway ◽  
Clot Retraction ◽  
Enzymatic Mechanism ◽  
Low Concentrations ◽  
Factor Xiia

SummaryClots formed from platelet rich plasma were found to be lysed more readily by low concentrations of pro-urokinase (pro-UK) than clots formed from platelet poor plasma. This was not a non-specific effect since the reverse occurred with tissue plasminogen activator. A mechanical explanation due to platelet-mediated clot retraction was excluded by experiments in which retraction was inhibited with cyto-chalasin B. Therefore, a platelet-mediated enzymatic mechanism was postulated to explain the promotion of fibrinolysis. Casein autography of isolated platelets revealed a ≈ 90 kDa band of activity which comigrated with plasma prekallikrein (PK)/kallikrein, a known activator of pro-UK. Furthermore, treatment of platelets with plasma PK activator (PPA), consisting essentially of factor XIIa, induced activation of pro-UK and of chromomgenic substrate for kallikrein (S-2302). This activity corresponded to approximately 40-200 pM kallikrein per 10 8 washed and gel filtered platelets per ml. The activation of pro-UK by PPA-pretreated platelets was dose-dependent and inhibited by soybean trypsin inhibitor but not by bdellin, a specific inhibitor of plasmin, nor by the corn inhibitor of factor XIIa. Kinetic analysis of pro-UK activation by kallikrein showed promotion of the reaction by platelets. The KM of the reaction was reduced by platelets by ≈ 7-fold, while the kcat was essentially unchanged. In conclusion, PK was shown to be tightly associated with platelets where it can be activated by factor XIIa during clotting. The activation of pro-UK by platelet-bound kallikrein provides an explanation for the observed platelet mediated promotion of pro-UK-induced clot lysis. Since pro-UK and plasminogen have also been shown to be associated with platelets, the present findings suggest a mechanism by which the factor Xlla-dependent intrinsic pathway of fibrinolysis can be localized and targeted to a thrombus.

Proteoglycan synthesis and deposition in fetal rat bone

Biochemistry ◽  
1984 ◽  
Vol 23 (7) ◽  
pp. 1572-1576 ◽  
Author(s):  
Graeme K. Hunter ◽  
Johan N. M. Heersche ◽  
Jane E. Aubin
Keyword(s):  
Proteoglycan Synthesis ◽  
Fetal Rat ◽  
Rat Bone

Thyroid hormones increase insulin-like growth factor I content in the medium of rat bone tissue

2009 ◽  
Vol 8 (12) ◽  
pp. 1475-1481 ◽  
Author(s):  
Peter Lakatos ◽  
Matthew D. Caplice ◽  
Vikram Khanna ◽  
Paula H. Stern
Keyword(s):  
Growth Factor ◽  
Thyroid Hormones ◽  
Bone Tissue ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Rat Bone

Activation of serum complement inhibits collagen synthesis in fetal rat bone in organ culture

1982 ◽  
Vol 34 (1) ◽  
pp. 370-375 ◽  
Author(s):  
Barbara E. Kream ◽  
Lawrence G. Raisz ◽  
Ann L. Sandberg
Keyword(s):  
Organ Culture ◽  
Collagen Synthesis ◽  
Serum Complement ◽  
Fetal Rat ◽  
Rat Bone

Biological Response to Wollastonite Doped α-Tricalcium Phosphate Implants in Hard and Soft Tissues in Rats

2008 ◽  
Vol 396-398 ◽  
pp. 7-10 ◽  
Author(s):  
Ana Maria Minarelli Gaspar ◽  
Sybele Saska ◽  
R. García Carrodeguas ◽  
A.H. De Aza ◽  
P. Pena ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Bone Formation ◽  
Bone Tissue ◽  
Tricalcium Phosphate ◽  
Rattus Norvegicus ◽  
Soft Tissues ◽  
Subcutaneous Tissue ◽  
Biological Response ◽  
New Bone Formation ◽  
Rat Bone

The biological response following subcutaneous and bone implantation of β-wollastonite(β-W)-doped α-tricalcium phosphate bioceramics in rats was evaluated. Tested materials were: tricalcium phosphate (TCP), consisting of a mixture of α- and β-polymorphs; TCP doped with 5 wt. % of β-W (TCP5W), composed of α-TCP as only crystalline phase; and TCP doped with 15 wt. % of β-W (TCP15), containing crystalline α-TCP and β-W. Cylinders of 2x1 mm were implanted in tibiae and backs of adult male Rattus norvegicus, Holtzman rats. After 7, 30 and 120 days, animals were sacrificed and the tissue blocks containing the implants were excised, fixed and processed for histological examination. TCP, TCP5W and TCP15W implants were biocompatible but neither bioactive nor biodegradable in rat subcutaneous tissue. They were not osteoinductive in connective tissue either. However, in rat bone tissue β-W-doped α-TCP implants (TCP5W and TCP15W) were bioactive, biodegradable and osteoconductive. The rates of biodegradation and new bone formation observed for TCP5W and TCP15W implants in rat bone tissue were greater than for non-doped TCP.

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