Brain-type Isoenzyme Of Creatine Kinase Research Articles

若齢犬の血清脳型クレアチンキナーゼ活性

若齢犬の血清脳型クレアチンキナーゼ活性

Stimulation of creatine kinase activity in rat skeletal tissue in vivo and in vitro by protease-resistant variants of parathyroid hormone fragments.

We have reported that mid-region fragments of human parathyroid hormone (hPTH), exemplified by hPTH-(28-48), stimulated [3H]thymidine incorporation into DNA and increased the specific activity of the brain-type isoenzyme of creatine kinase (CK) in both skeletal-derived cell cultures (ROS 17/2.8 cells) and immature rat epiphyseal cartilage and diaphyseal bone, without stimulating cyclic AMP synthesis which is a prerequisite for bone resorption. In the present study, substitution of amino acids in hPTH-(28-48), which resulted in increased resistance to proteolysis, produced variants that stimulated skeletal systems at two orders of magnitude lower concentration than the wild-type fragment. We modified hPTH-(28-48) at Leu-37 by replacement with Met, Thr or Val. Under conditions in which 20% of the native hPTH-(28-48) resisted proteolysis by cathepsin D for 6 h, approx. 40% of the L37V mutant and 70% of the L37T mutant remained intact. Substitution of Met for Phe-34 in addition to Thr for Leu-37, or the substitution of Met for Phe-34 alone, produced 100%-resistant fragments. These variants at residue 34 caused maximal stimulation of CK in ROS 17/2.8 cells at 0.24 nM compared with 24 nM for hPTH-(28-48). The double mutant stimulated CK activity significantly in immature rats, at a minimum dose of 12.5 ng/rat, and caused maximal stimulation at 125 ng/rat, a 10-fold lower dose than for hPTH-(28-48). The effect of the double mutant lasted up to 24 h which differs from the stimulation by hPTH-(28-48) in which CK specific activity returns to the control level at 24 h. This same dose also significantly stimulated CK activity in gonadectomized rats. These results show the advantage of using protease-resistant mid-region variants of hPTH-(28-48) to stimulate bone cells, in terms of lower doses and longer duration of effectiveness, both in vitro and in vivo.

脳疾患犬における血清クレアチンキナーゼ-BB活性値の上昇

脳疾患犬における血清クレアチンキナーゼ-BB活性値の上昇

Evaluation of hypoxic brain injury with spinal fluid enzymes, lactate, and pyruvate.

To investigate the prognostic importance in neurologic recovery of the lumbar cerebrospinal fluid (CSF) variables creatine kinase (CK) and brain-type creatine kinase isoenzyme (CK-BB), lactate dehydrogenase (LDH) and its isoenzymes (LDH 1-5), CSF acid phosphatase, beta-D-N-acetylglucosaminidase activity, and CSF lactate, pyruvate, sodium, potassium, and calcium concentrations in patients who experienced cardiac arrest. Prospective clinical study with blood and CSF samples collected 4, 28, 76, and 172 hrs after resuscitation. Medical ICU in a university hospital. Twenty consecutive victims of out-of-hospital cardiac arrest. Eight patients recovered neurologically and 12 patients remained comatose or neurologically disabled until death. CSF CK, CK-BB, LDH, and LDH isoenzyme 1-3 concentrations in all disabled patients were markedly increased at 76 hrs after the resuscitation. However, these variables were not changed in the recovered subjects. Patients (n = 7) with a mean CSF CK level of 25 +/- 33 (SD) U/L, CK-BB 23 +/- 33 U/L, and CSF lactate 3.8 +/- 0.9 mmol/L at 28 hrs after cardiac arrest remained unconscious and died. In the recovered patients, the mean CSF CK concentration was 2.0 +/- 1.5 U/L (p less than .001) and CSF lactate concentration 2.5 +/- 0.5 mmol/L (p less than .002). The lactate concentration was highest at 4 hrs after resuscitation, declining thereafter. Patients with a mean CSF total LDH level of 609 +/- 515 U/L and acid phosphatase 2.4 +/- 1.2 U/L 76 hrs after resuscitation died without regaining consciousness. In the recovered patients, the mean total CSF LDH activity was 82 +/- 58 U/L (p = .003) and CSF acid phosphatase was 0.8 +/- 0.5 U/L (p = .01) 76 hrs after resuscitation. CSF CK, CK-BB, and CSF lactate concentrations reflect a patient's outcome most reliably when measured within 28 to 76 hrs of the cardiac arrest. Similarly, CSF LDH, its isoenzymes 1-3, and CSF acid phosphatase concentrations, when measured at 76 hrs, can be used to monitor the patient's outcome after cardiac arrest. When correlated with Glasgow Coma Scale scores, the closest negative correlation was again seen in CSF CK and CK-BB at 28 and 76 hrs, as well as in LDH, LDH1-3, and acid phosphatase values at 76 hrs. The negative correlation between CSF lactate and Glasgow Coma Scale scores was most distinct at 28 hrs.

Stimulation of cell proliferation in skeletal tissues of the rat by defined parathyroid hormone fragments

We have found, in previous studies in vitro using skeletal derived cell cultures, that mid-region fragments of human parathyroid hormone (hPTH) stimulate [3H]thymidine incorporation into DNA and increase the specific activity of the brain-type isoenzyme of creatine kinase (CK). These changes occurred without an increase in cyclic AMP formation which is linked to bone resorption. In this study, we found that the mid-region fragment hPTH-(28-48) stimulated CK activity in diaphysis, epiphysis and kidney in a time- and dose-dependent manner, parallel to the effects of the whole molecule bovine (b)PTH-(1-84) and the fully active fragment hPTH-(1-34). The increase caused by hPTH-(28-48) at a dose of 1.25 micrograms/rat was not less than the 2-fold increase caused by a roughly equimolar concentration bPTH-(1-84). A significant increase was reached at 1 h after intraperitoneal injection in all cases. All three sequences of PTH caused an increase in [3H]thymidine incorporation into DNA in diaphysis and epiphysis, but not in kidney, 24 h after injection. A fragment further towards the C-terminal, hPTH-(34-47), was inactive compared with an equimolar concentration of the fragment hPTH-(25-39), which stimulated both CK activity and DNA synthesis. These results in vivo are in line with previous findings in vitro; they provide further support for the suggestion that mid-region fragments of the PTH molecule could be used to induce bone formation without incurring the deleterious effect of bone resorption.

Hypoxic risk in twins assessed by serum creatine kinase brain isoenzyme measurement

A marked intrapair discordance in placentas and in many body and organ measurements are risk factors influencing perinatal mortality and morbidity in twins. Asphyxia is the single most important perinatal cause of neurologic morbidity in newborn infants. The higher hypoxic risk for the second twin arises, however, from conclusions based on studies that did not consider the new diagnostic possibility of using blood measurements of the brain-type isoenzyme of creatine kinase (CK-BB) as a marker of perinatal asphyxia. CK-BB levels were measured in cord blood of 60 preterm infants (mean birth weight 1670 ± 390 g, and mean gestational age 33 ± 1.9 weeks) born of twin gestation in the last 3 years. The mean CK-BB values were 48 ± 40 U/1 versus 29 ± 31 U/1 (p > 0.5). Skilful antepartum and perinatal care are the keys for optimal management of both babies, as demonstrated by similar CK-BB values obtained in their cord-blood specimens after birth.

Creatine kinaseBB-activity after head trauma related to outcome.

The brain-type isoenzyme of creatine kinase was determined in serum (S) and cerebrospinal fluid (CSF) in 37 patients with severe head injury, and a correlation was made with the Glasgow coma score and Glasgow outcome score. All patients with normal S-CKBB and CSF-CKBB activities had a coma score of 15, i.e., no neurological deficits, at six hours after the trauma and a good outcome. All 15 patients with a significant increase in the enzyme in serum and CSF had a coma score less than 15. The outcome was still good for five of these patients, while six were moderately disabled, two were severely disabled, and two died. There was no correlation between the individual CKBB-values and the outcome.

Expression of creatine kinase isoenzyme during oogenesis and embryogenesis in the mouse

Creatine kinase activity was discovered in the growing mouse oocyte and in the preimplantation embryo. Changes in the enzyme activity during the growth and maturation of the egg and during the development of the embryo up to the blastocyst stage were determined. Close similarity of the protein to the brain-type isoenzyme of creatine kinase was established immunochemically. The kinetic parameters of the brain-type isoenzyme ( M. R. Iyengar, C. E. Fluellen, and C. W. L. Iyengar, 1982, J. Muscle Cell Motil. 3, 231–246) and the pattern of development-associated changes in activity suggest a possible role for creatine kinase in maintaining the reported high ATP/ADP ratio ( L. Ginsberg and N. Hillman, 1975, J. Reprod. Fertil. 43, 83–90), which is essential for the biosynthetic activities of the embryo.

Assessment of neurologic outcome in asphyxiated term infants by use of serial CK-BB isoenzyme measurement

Brain-type isoenzyme of creatine kinase was measured serially in 45 healthy and 22 severely asphyxiated term infants. The enzyme was measured in cord blood and in venous, capillary, or arterial blood at six to eight hours, 24 to 30 hours, and 72 to 80 hours after birth. In the healthy infants a brief rise of CK-BB occurred at six to eight hours; CK-BB activities were greater than 2.5 log-transformed standard deviations above the mean of the control values in ten of the asphyxiated infants and in none of the control infants. When normal CK-BB activity was used as a predictor of good neurologic outcome and elevated CK-BB as a predictor of subsequent neurologic abnormality, the outcome was predictable from the CK-BB activity in 17 of 22 cases (77%) and in 11 of the 12 survivors (92%). Eight of the 12 surviving infants had neonatal seizures and outcome was predictable from CK-BB activity in all cases. We conclude that serum CK-BB activity, especially when measured in cord blood and at six to 12 hours of life, correlates with neurologic outcome after severe asphyxia, and that measurement of CK-BB compares favorably with radionuclide and computerized tomographic scanning as a method of predicting neurologic outcome after asphyxia.

Blood Platelets as a Possible Source of Creatine Kinase in Rat Plasma and Serum

The creatine kinase (CK) activity in rat plasma was found to be correlated with that in serum or platelets. Rat serum contained higher activity not only of CK but also of lactate dehydrogenase than the corresponding plasma. The plasma CK activity decreased with increasing age of rats. Only the brain-type isoenzyme of CK was found in plasma, serum and platelets. Contamination of brain-type with muscle-type isoenzyme was detected in rather exceptional cases in which the activity was high among old rats. These results suggest the possible contribution of blood platelets to the CK activity of circulating plasma as well as to the activity in serum in rats.

Brain-type creatine kinase isoenzyme. Occurrence in serum in acute cerebral disorders.

Acute brain damage-cerebrovascular or cardiovascular, traumatic or infectious-released brain-type isoenzyme of creatine kinase (BB-CK) into the circulation within a few hours in 16 of 62 patients (26%). Occurrence of BB-CK was transient in the serum. BB-CK activity was found in the peripheral blood in 13 of 23 patients with diffuse brain damage compared to three of 39 patients with a local cerebrovascular accident (P less than .0005). The mortality of patients having BB-CK in their serum was 63% compared to 39% of those without BB-CK activity in their serum (P less than .05).