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PubMed1985

Beneficial effects of high-dose intravenous gammaglobulin on the accelerated phase of Chediak-Higashi syndrome.

The Chediak-Higashi syndrome (CHS) is a rare, autosomal-recessively inherited disease characterized by giant cytoplasmic granules in neutrophils, monocytes and lymphocytes. It has been reported that a lymphoma-like illness develops in the accelerated phase of the syndrome and that early death ensues. Treatment of CHS has not been established, particularly when the accelerated phase develops. We treated a 15-year-old boy, who had entered into the accelerated phase, with high-dose intravenous gammaglobulin. The treatment was beneficial in the management of accelerated phase of CHS.

Adolescent↗

PubMed1981

A high acceleration programmable centrifuge used in purification of myocardial and skeletal muscle myosins.

Protein purification can be improved by using high acceleration - deceleraton centrifugation. This study describes a high acceleration programmable centrifuge which reaches 5,000 x g in 3 sec and brakes from 5,000 to 0 x g in 4.3 sec. This study further describes the use of this centrifuge in myosin purification and thus demonstrates that protein purification can be improved by separating particles with a high acceleration - deceleration centrifuge for the following reasons: (1) biological and chemical equilibria are immediately terminated, (2) proteolysis is reduced, (3) working time is decreased, and (4) the native state of labile proteins are better preserved. Rapid acceleration and deceleration is advantageous in reducing centrifugation time for separation of particles because it decreases diffusion time of particles and non-desirable interactions.

Adenosine Triphosphatases↗

PubMed1984

[Effect of secular acceleration on the human brain weight and its changes during aging].

The presented examinations on humans are based on 26 publications regarding the secular acceleration and 16 regarding the brain weight (each of the latter containing at least 500 values). The secular acceleration of the body length was only insignificant up to 1800 AD (about 1 mm per 100). From 1800 to 1900, the size of the length increased steadily and reached finally a size of 1 to 1.2 mm/a which is probably unchanged at present. This behaviour can be observed in every country in which such data were sampled. A positive correlation between brain size and body length can be found in a sample of about 11,000 values. An increase of 10 cm body-length corresponds to an increase of 59 g in brain weight, respectively 10 g brain weight are equal to 1.7 cm body-length. 21,300 values of 15 transversal examinations regarding brain weight and age compare the brains of the older and smaller generation having primarily smaller brains with those of the younger generation having primarily larger brains. Therefore the observed diminution of the brain weight during ageing is partly fictitious. With the help of correlation between brain weight and body length on the one hand and the secular acceleration of the body length on the other hand it is possible to correct the fictitious part of this diminishing. The result can state that the real diminution of the brain begins around the 60th year of age. However, it is probable that a high individual variability concerning time and speed exists. At present, the ideas regarding the sources of the secular acceleration are highly speculative.

Adolescent↗

PubMed1984

[Blood testosterone levels in nonpsychotic psychopath-like behavior disorders among adolescents with accelerated or delayed physical development].

The authors examined 128 male adolescents admitted to a psychiatric hospital for the psychopathlike syndrome free of psychotic manifestations which was associated with the abnormal rate of sexual development. A correlation was established between the maturation rate, plasma testosterone levels and clinical features of behavioural abnormalities. Retarded puberty was related to decreased testosterone concentrations throughout the pubertal period. In cases of accelerated development the testosterone content was increased at the age of 14-15 years, i.e. in the period of the most intensive maturation; later on, in the process of reaching puberty, the hormone level approaches the age specific rate. The clinical picture of behavioural disorders in the presence of retarded or accelerated development depends on whether the symptoms caused by abnormal rates of maturation were combined with the symptoms of cerebral insufficiency. Adolescents with accelerated development unattended by cerebral insufficiency manifestations were characterized by marked aggression and an increase in desires. Depending on the degree of activity, asthenic nature, leadership capacities and the level of intellect, they are divided into two clinical variants: epileptoid and conformational-epileptoid types of accentuations. Cerebral insufficiency was reflected in the form of lowered intellect, explosiveness and impaired desires in the clinical picture of both accelerated and retarded pubertal development.

Adolescent↗

PubMed1983

Accelerated 86Rb+ (K+) release from the cytotoxic T lymphocyte is a physiologic event associated with delivery of the lethal hit.

Cloned CTL have been loaded with the K+ analogue 86Rb+. When mixed with unlabeled target cells, accelerated 86Rb+ release occurs from the CTL. The magnitude of accelerated 86Rb+ release is proportional to the efficacy of the target in standard 51Cr release assays. The signal responsible for accelerated 86Rb+ release has been localized to a postbinding event and has the physiologic requirements of delivery of the lethal hit. Thus, accelerated 86Rb+ release from the CTL represents the first direct observation of a physiologic event within the CTL related to a functional CTL-target interaction.

Animals↗

PubMed1977

[Accelerated idioventricular rhythm in acute myocardial infarct].

A continuous (for 24 hours) ECG recording on a magnetic tape with its subsequent decodification on a special analyser was performed in 31 patients with acute myocardial infarction during the 1st day of the onset of the disease in order to reveal an accelerated idioventricular rhythm and ventricular tachycardia. An accelerated idioventricular rhythm was found to occur within the 1st and early during the 2nd day of the disease in 29% of the patients. The importance of some factors, that of the sinus rhythm rate in particular, was studied with reference to the development of an accelerated idioventricular rhythm. The causes of its development are discussed, as well as those of its disappearance, interrelationship with ventricular tachycardia, and the prognostic importance of the accelerated idioventricular rhythm recorded throughout a 3-month observation and its place in the differential diagnosis in acute myocardial infarction.

Acute Disease↗

PubMed1981

Accelerations in "intra-partum" cardiotocographic record. III. Correlation with meconium staining of amniotic fluid.

The Authors examined perinatal outcome and presence of accelerations in cardiotocographic records in a group of patients showing meconium staining of amniotic fluid in labor, in comparison with the data of a control group. The first group showed an average Apgar between 1' and 5' and an average number of accelerations every 30' significantly lower than those of the control group. Moreover the study of accelerations confirmed that an average of more than 5 accelerations every 30' is a clear indicator of fetal well-being.

Amniotic Fluid↗

PubMed1981

[Secular acceleration of the physical development of Czech school children (author's transl)].

The presented contribution reports on the acceleration of physical development and pubescence of school children, based on anthropometrical studies dating of 1895, 1951, 1961 and 1971. Since 1895 the acceleration for the development has been recorded by .2 to 2.5 years. The acceleration of the growth of body height and mass was less during 1961--1971 than within the period of 1951--1961. The higher mean values found 1971 in children and youth of Prague suggest that possible secular acceleration in our adolescents has not been terminated so far.

Adolescent↗

PubMed1995

[Stereotactic radiotherapy with linear accelerators. Dosage considerations on collimators and photon beam energy].

The small X-ray beam profiles produced by linear accelerators and used in stereotactic radiosurgery were studied. Circular focusing and not-focusing beams outlined by additional collimators (diameter ranging 10 to 30 mm) and square field outlined by the jaws (field size 10 to 30 mm) were measured. 6 and 18-MV X-ray beams from a dual energy accelerator and 6 and 15-MV X-ray beams produced by 2 single-energy accelerators were used. Measurements were carried out with Kodak X Omat V films in a perspex phantom in the same conditions for all the fields. To study the profile characteristics we introduced the V80/V20 = (R80/R20)3 ratio where R80 and R20 are respectively the mean distance of the 80% and 20% isodose lines from the beams axis. Measurement results show that 6-MV X-ray beams have a higher V80/V20 ratio than the ones obtained with the other energies. There is no significant difference between the beams produced with focused collimators and those produced with not-focused collimators. Square fields outlined by the jaws have a V80/V20 ratio greatly dependent on the accelerator used. This ratio is generally worse than the ones obtained with beams outlined by additional collimators.

Photons↗

PubMed1993

Tyrosine-rich acidic matrix protein (TRAMP) accelerates collagen fibril formation in vitro.

Tyrosine-rich acidic matrix protein (TRAMP) is a recently discovered protein that co-purifies with porcine skin lysyl oxidase and is equivalent to the M(r) 22,000 extracellular matrix protein from bovine skin that co-purifies with dermatan sulfate proteoglycans (Cronshaw, A. D., MacBeath, J. R. E., Shackleton, D. R., Collins, J. F., Fothergill-Gilmore, L. A., and Hulmes, D. J. S. (1993) Matrix 13, 255-266; Neame, P. J., Choi, H. U., and Rosenberg, L. C. (1989) J. Biol. Chem. 264, 5474-5479). The effect of TRAMP on collagen fibril formation was studied in vitro by reconstitution of fibrils from lathyritic rat skin collagen I. Fibril formation was initiated by the warm start procedure, in which acidic collagen solutions and double strength neutral buffer, both preincubated separately at 34 degrees C, were mixed. When monitored by turbidimetry, TRAMP was found to accelerate collagen fibril formation. Acceleration occurred at sub-stoichiometric molar ratios of TRAMP collagen, and the presence of TRAMP stabilized the fibrils against low temperature dissociation. It was confirmed by centrifugation that the amount of fibrillar collagen formed in the presence of TRAMP was greater than in its absence. By SDS-polyacrylamide gel electrophoresis and scanning densitometry, binding of TRAMP to collagen was detected that approached saturation with a molar ratio of TRAMP to collagen of approximately 1:2. Fibrils formed in the presence of TRAMP were normal when observed by electron microscopy, although fibril diameters were smaller than the controls. TRAMP was found to partially reverse the inhibitory effects of urea and increased ionic strength on the kinetics of fibril formation, although inhibition by glucose was unaffected. TRAMP also accelerated the assembly of pepsin-treated collagen, where the non-helical, telopeptide regions were partially removed. Acceleration of collagen fibril formation by TRAMP is discussed in the light of the known effects of other extracellular matrix components on this process.

Animals↗

PubMed1994

Enhancement of rod outer segment GTPase accelerating protein activity by the inhibitory subunit of cGMP phosphodiesterase.

The cGMP phosphodiesterase (PDE) of retinal rod outer segments (ROS) is activated by the GTP-bound form of the G protein, transducin (Gt alpha). This activation can be reversed by the inhibitory gamma subunit of PDE through two distinct mechanisms: acceleration of GTP hydrolysis and direct inactivation independent of GTP hydrolysis. We have found that acceleration of Gt alpha GTPase by PDE gamma does not occur upon formation of a Gt alpha PDE gamma complex but rather reflects enhanced activity toward this complex of a membrane-bound GTPase accelerating protein. GTPase rate constants for Gt alpha in the presence of 3.3 microM PDE gamma were as high as 0.7 s-1 with hypotonically washed ROS membranes at 40 microM rhodopsin but were more than 10-fold lower when protein-free vesicles containing ROS lipids were substituted for ROS membranes. Acceleration of Gt alpha GTPase by PDE gamma was also barely detectable at low ROS concentrations (e.g. 4 microM rhodopsin) or if ROS treated with trypsin or urea were used. GTPase-independent inactivation by PDE gamma occurred efficiently at much lower membrane concentrations. Inhibition of Gt alpha-activated PDE was much slower than inhibition of PDE alpha beta by PDE gamma. Effects of PDE gamma upon successive additions of GTP suggested formation of a complex of PDE gamma and Gt alpha-GDP that is refractory to reactivation.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1977

Decreased surface charge and accelerated senescence of red blood cells following neuraminidase treatment.

Female LAF1 mice were given single or repeated injections of V. cholerae N'ase and the effects on circulating RBC surface charge and life span were determined. Intravenous injection of N'ase caused a rapid decrease in RBC surface charge of approximately 14 percent, and survival of such treated cells was reduced by approximately one fifth by virtue of an acceleration of senescence. When RBC's were treated in vitro with N'ase, a comparable (14 to 17 percent) reduction in surface charge was seen. Such cells, when injected into intact mice, showed a similar acceleration of senescence. When N'ase was injected intravenously into splenectomized mice, RBC survival was similar to that of controls. Intravenous injection of N'ase 1 hour before injection of labeled RBC's did not alter RBC survival nor did it accelerate the clearance of carbon particles by the RES. These results indicate that N'ase accelerates senescence in treated mouse erythrocytes by acting on the RBC's and not by activating the RES. Absence of this effect in splenectomized mice implicates the spleen as the sensor of the induced alterations in surface charge. These results and those recently reported for treated RBC's in the dog, rat, rabbit, and man suggest that at least a portion of the phenomenon of RBC senescence may be related to the loss of RBC surface charge.

Animals↗

PubMed1993

Surface-independent acceleration of factor XII activation by zinc ions. I. Kinetic characterization of the metal ion rate enhancement.

The effect of zinc ions (Zn(II)) on the activation of factor XII in the absence of a procoagulant surface was investigated by initial velocity kinetic studies at I = 0.15, pH 7.4, and 25 degrees C. Zinc ions at concentrations greater than 160 microM potentiated 99-fold the kcat/KM for the activation of factor XII by kallikrein and, at an optimum concentration of 110 microM, accelerated 140-fold the apparent kcat/KM for factor XII autoactivation. High molecular weight kininogen had no effect on either metal-potentiated reaction. Analysis of the factor XII concentration dependence of initial activation rates revealed that Zn(II), at levels that saturate the effect, accelerates kallikrein activation of factor XII by lowering KM (from 52 to 7.3 microM) and raising kcat (from 2.6 to 31 min-1). For the autocatalytic activation reaction of factor XII in the presence of optimal Zn(II), apparent KM and kcat values of 2.4 microM and 0.041 min-1, respectively, were determined, but these parameters were not resolvable in the absence of the metal ion. Zinc ions minimally affected kallikrein enzymatic activity and inhibited factor XIIa enzymatic activity with KI values of 20-40 microM, suggesting that the rate-enhancing effects of the metal ion are due to interactions with the substrate (factor XII) rather than with the enzyme. The Zn(II) inhibition of factor XIIa enzymatic activity accounted for a decreased Zn(II) enhancement of factor XII autoactivation at high metal ion concentrations (> 110 microM). The Zn(II) concentration dependence of the acceleration of factor XII activation reactions were sigmoid and characterized by Hill coefficients of 3.3-4.3, suggesting that cooperative binding of at least four zinc ions to factor XII was responsible for the Zn(II) potentiating effect. The Zn(II) enhancement of the rates of factor XII activation decreased both above and below pH 7.4 with midpoint pH values of 6.5-7.0 and 8.0, consistent with histidine and possibly water ligands mediating Zn(II) binding to the protein. Despite an apparent weaker binding of Zn(II) to factor XII at pH 6.5, indistinguishable maximum accelerating effects of the metal ion were observed at saturation at this pH, indicating that the increased positive charge of factor XII resulting from protonation at the lower pH did not mimic the effect of Zn(II) binding. These results imply that zinc ions induce a conformational change in factor XII that makes it a better substrate for its enzyme activators.

Factor XII↗

PubMed1996

RANTES chemokine expression in transplant-associated accelerated atherosclerosis.

BACKGROUND: The pathogenesis of transplantation-associated accelerated atherosclerosis is poorly understood, but it is likely to be an alloimmune response involving infiltration of the vessel wall by T lymphocytes and monocytes leading to smooth muscle cell proliferation and extracellular matrix deposition. RANTES is a chemokine that selectively chemoattracts T lymphocytes, NK cells, monocytes, and eosinophils. The expression of RANTES in accelerated atherosclerosis was investigated by in situ hybridization and immunohistochemistry. METHODS: Coronary arteries from six patients undergoing accelerated atherosclerosis were obtained at the time of retransplantation. Normal coronary arteries from two patients with idiopathic dilated cardiomyopathy were used as controls. Messenger RNA for RANTES was localized with digoxigenin-labeled complementary DNA probes. RANTES protein was detected by use of a monoclonal antibody and a three-step horseradish peroxidase method. RESULTS: RANTES mRNA and protein were detected in the lymphocytes, macrophages, myofibroblasts, and endothelial cells of arteries undergoing accelerated atherosclerosis but not in normal coronary arteries. CONCLUSIONS: In view of its in vitro biologic activity and in vivo expression pattern, RANTES may be a pivotal mediator of the cellular infiltrate seen in graft atherosclerosis. This information may help in the design of novel diagnostic and therapeutic approaches to this increasingly important disease process.

Adult↗

PubMed1977

[Investigations on acceleration of processes of differentiation and aging in rats after influence of x-ray (author's transl)].

On the basis of the hypothesis of a relation between the processes of differentiation and aging in connection with the assumption, that ionizing radiation accelerates the aging of organism, the authors investigated the changes in the cellular reaction in organ cultures of the spleen and the kidney, in the pattern of enzymes in the kidney and the liver and moreover the behaviour of the serum protein level. In dependence of the x-ray dosis and the length of time after radiation an acceleration of the processes of maturation and differentiation could be observed with the three above mentioned methods. Changes could be found which were similar to those, observed in adult or senile rats. The latent phase or organ cultures was prolonged as well as the morphology of cells migrating out of the explants did not differ from that of senile donor animals. The chemical differentiation of the kidney is accelerated after radiation. The detected changes were similar to those in adult or senile rats. The increase in the albumin, haptoglobin and transferrin concentrations of juvenile rats following radiation mean an acceleration of development, for these concentrations are attained during normal development. The authors discuss their results with reference to the existing theories of aging.

Aging↗

PubMedDate not supplied

Role of accelerated fractionated irradiation for supraglottic carcinoma: assessment of results.

PURPOSE: We evaluated the results of locoregional control, patients' relapse-free survival, and voice preservation in patients with supraglottic carcinoma treated with accelerated radiation therapy. PATIENTS AND METHODS: The records of 164 patients undergoing accelerated fractionated radiation therapy for carcinoma of the supraglottis from 1981 to 1992 were reviewed and evaluated for locoregional control, disease-specific survival, and rates of voice preservation. All patients were treated with 1.6 Gy per fraction two fractions a day (BID) for 67.2 to 70.0 Gy in 6 weeks. The median follow-up was 56 months. Due to severe acute mucosal toxicity, all patients were given a short treatment break after 38.4 to 48.0 Gy. RESULTS: For T1, T2, T3, and T4 tumors, the 5-year actuarial local control rates were 96%, 86%, 76%, and 43%, respectively, and relapse-free survival rates were 78%, 82%, 64%, and 40%, respectively. With surgical salvage, the corresponding ultimate local control rates for the T1, T2, T3, and T4 tumors were 96%, 93%, 88%, and 51%, respectively. Regional control by T and N stage was non-significant. Voice preservation rates for the T1, T2, T3, and T4 tumors were 96%, 80%, 72%, and 43%, respectively, and for the entire group the rate was 79%. CONCLUSIONS: Accelerated fractionated radiation therapy resulted in excellent locoregional control, relapse-free survival, and voice preservation rates for patients with supraglottic carcinoma. The T stage and N stage were significant predictors of outcome. T4 tumors and node-positive neck disease portended a poor prognosis. These results as compared to our historical control and the published data in the literature with conventional once-daily radiation therapy (QD) suggested improved local control and patient survival after accelerated fractionated BID radiation therapy. For confirmation of these results, a prospective randomized trial is needed.

Carcinoma, Squamous Cell↗

PubMed1997

Reversal of accelerated renal allograft rejection with FK 506.

Although FK 506 has been shown to effectively reverse refractory renal allograft rejection, its ability to reverse accelerated renal allograft rejection as a primary agent has not been specifically addressed. Herein evidence of the ability of FK 506 to reverse accelerated renal allograft rejection is presented. A 16-yr-old highly sensitized (PRA 75%) male underwent a second cadaveric renal transplant procedure. Despite induction immunosuppression with ATGAM, cyclosporine, azathioprine, and corticosteroids, a marked elevation in serum creatinine (1.6-->2.1 ng/dl) and reduction in urine output (4000 ml/d-->1000 ml/d) were observed on the sixth post-transplant day. Renal allograft biopsy performed at that time revealed typical features of accelerated rejection including neutrophil margination in glomerular and interstitial capillaries, and C3, IgG, and fibrin deposition in glomerular and interstitial capillaries (by immunofluorescence). FK 506 therapy was promptly instituted and ATGAM therapy discontinued. Serum creatinine peaked within 3 d of FK 506 therapy (2.5 mg/dl) and subsequently progressively dropped to 1.2 mg/dl. Repeat biopsy on FK 506 treatment day 12 revealed marked histologic improvement. Renal function remains excellent (1.3 mg/dl) 18 months after initiation of FK 506 therapy, and recurrent rejection has not been observed. This experience provides evidence that FK 506 therapy may effectively reverse accelerated renal allograft rejection, and that it provides a means for treating antibody-mediated mechanisms of allograft rejection.

Adolescent↗

PubMed1996

A comparative study of intravenous accelerated streptokinase dose regimen with conventional dose regimen for coronary thrombolysis.

The aim of this study is to test the patency rate and safety of the accelerated streptokinase dose regimen for coronary thrombolysis compared with the conventional one. One hundred and four patients entering three hospitals up to 12 hours after the onset of definite acute myocardial infarction were randomizely treated with intravenous accelerated streptokinase dose regimen (1.5 million units/30 min) (group A, 47 cases) and conventional dose regimen (1.5 million units/60 min) (group B, 57 casese). The reperfusion rate of infarct-related arteries determined by clinical evidence of reperfusion was 76.6% (36/47) in group A VS 61.4% (35/57) in group B. There was significant difference in reperfusion rates among patients within 6 hours after the onset of chest pain: 87.9% (29/33) in group A VS 67.4 (29/43) in group B (P < 0.05). The incidence of mild bleeding, allergic reaction, hypotension was 12.8% (6/47), 4.3% (2/47), 12.8 (6/47) respectively in group A vs 21.1 (12/57), 3.5 (2/57), 17.5% (10/57) respectively in group B. Compared to conventional dose regimen, intravenous accelerated streptokinase dose regimen for coronary thrombolysis seems to improve reperfusion rate markedly without increasing adverse events such as bleeding, allergic reaction and hypotension. It suggests that accelerated streptokinase therapy deserves more extensive investigation.

Aged↗