Brain Oxygenation and Metabolism during Repetitive Apnea with Resuscitation of 21% and 100% Oxygen in Newborn Piglets

The oxygen distribution in the microcirculation of the piglet’s brain and striatal extracellular dopamine were determined during repetitive apnea and resuscitation with 21% or 100% oxygen. Pre-apnea cortical oxygen was 49.5 ± 10.4 mm Hg and during each apnea decreased to 8 ± 0.9 mm Hg. After ten apneic episodes followed by resuscitation with 21% or 100% oxygen, 7.48 ± 1.6% or 2.6 ± 0.5% of the tissue volume was below 10 mm Hg, respectively. Extracellular dopamine increased progressively with an increase in the number of apneas with resuscitation of 21% oxygen and at the end of ten apneic episodes it was up to 59,500 ± 11,320% of control. There was no increase in extracellular dopamine during apnea resuscitated with 100% oxygen. Repetitive apnea caused progressive increase in fraction of hypoxic brain tissue in newborn. The magnitude of the increase is dependent on whether the animals were resuscitated with room air or 100% oxygen.     

DNA ploidy and proliferative activity of human pulmonary epithelium

DNA ploidy and distribution has been determined in normal and abnormal bronchial, bronchiolar and alveolar epithelium from 22 patients, aged between 0 and 85 years, 9 of whom had received chemotherapy for malignant disease. The DNA ploidy was diploid in all the specimens examined. The S + G2/M fraction was significantly greater in diseased than normal bronchial trees. In the bronchial epithelium, mean values ± the standard deviation (SD) were 5.5 + 2.2% vs 1.1±0.6%, in bronchiolar epithelium 4.6 ± 1.6% vs 1.0 ± 0.9% and in alveolar epithelium 4.6 ± 1.6% vs 0.8 ± 0.5%. The highest S + G2/M value of 8.9% was obtained from inflamed bronchial epithelium. Polyploid cells up to the octaploid range occurred infrequently but their incidence was slightly increased to between 0.16% and 0.9% in diseased lungs and in patients who had received chemotherapeutic drugs. It was concluded that (1) non-cancerous pulmonary epithelium is diploid, that (2) pulmonary epithelium shows steady-state renewal at all ages and polyploid cells are rare under normal conditions and that (3) the S + G2/M fraction increases up to approximately 10% in reactive proliferative states.     

Subcellular distribution of tissue radiocopper following intravenous administration of 67Cu-labeled Cu-PTSM

The subcellular distribution of radiocopper in the brain and liver of rats has been determined following i.v. administration of Cu-PTSM, pyruvaldehyde bis(N⁴-methylthiosemicarbazonato)copper(II), labeled with copper-67. Homogenized tissue samples were separated by differential centrifugation into four subcellular fractions: (I) cell membrane + nuclei; (II) mitochondria; (III) microsomes; and (IV) cell cytosol. Upon sacrifice at 10 min post-Cu-PTSM injection, brain fractions, I, II, III and IV contain 35 ± 12, 11 ± 3, 2.8 ± 1.3 and 51 ± 7% of brain activity, respectively (n = 4). In animals sacrificed 24 h post-injection the subcellular fractions of brain tissue show little change from the radiocopper distribution seen at 10 min post-injection, although the mitochondrial fraction may contain slightly more tracer and the cytosolic fraction slightly less (I, 40 ± 10%; II, 18 ± 5%; III, 3.4 ± 1.5%; and IV, 38 ± 5%; n = 5). Subcellular fractions I, II, III and IV of liver contain 25 ± 5, 12 ± 3, 17 ± 4 and 46 ± 6% of ⁶⁷Cu tracer in animals sacrificed 10 min post-Cu-PTSM injection. An identical subcellular distribution of ⁶⁷Cu, was found in the liver following i.v. administration of ionic radiocopper (as Cu-citrate). The liver and brain cytosolic fractions at 10 min post-injection were further separated by Sephadex column chromatography. In liver cytosol, three different radiocopper components with molecular weights of about 140,000, 41,000–46,000 and 10,000–16,000 Da were found. In the brain supernatant fraction, most of the radiocopper was bound to a single low molecular weight cytosolic component (14,000–16,000 Da). These results suggest that the intracellular decomposition of tracer Cu-PTSM may result in the radiocopper entering the normal cellular pools for copper ions.     

ALTERATION OF CELLULAR PROLIFERATION IN THE ILEAL EPITHELIUM OF SUCKLING AND WEANED RATS: THE EFFECTS OF ISOPROTERENOL

The purpose of this study was to analyse cell proliferation in the ileum before and after neonatal closure to macromolecules and to determine the effects of the sympathomimetic amine, isoproterenol (IPR), on cell cycle parameters. 8- and 28-day-old rats were employed in this study representing the neonatal periods of pre- and post-closure ileum respectively. The duration of the cell cycle phases was determined by the percentage of labeled metaphases technique (PLM) with computerized analysis of the curves. The generation cycle time was longer in 8-day-old suckling rats (18.63 hr) as compared to the older weaned rats (11.85 hr), and most of this 6.78 hr difference was in the G₁-period (4.5 hr). Other proliferative indices were also lower in the suckling rats—mitotic index (1.9 ± 0.4% as compared to 6.7 ± 0.9%), labelling index (26.8 ± 2.5% versus 44.2 ± 2.6%) and migration rate measured as per cent labeled villus cells (8.9 ± 3.1% versus 45.2 ± 3.4%). IPR was found to inhibit cellular proliferation in the ileal epithelium of both age groups. The cell cycle of the ileal epithelium of 8-day-old rats was lengthened from 18.63 to 21.07 hr and 28-day-old rats from 11.85 to 13.98 hr. IPR produced a decrease in mitotic index from 1.9 ± 0.4% to 1.6 ± 0.4% in pre-closure ileum and from 6.7 ± 0.9% to 5.1 ± 0.6% in post-closure ileum. Labeling index decreased from 26.8 ± 2.5% to 20.0 ± 2.0% in 8-day-old rats and from 44.2 ± 2.6% to 31.1 ± 3.0% in 28-day-old rats after IPR administration. There were also significant differences in growth fraction between age groups and a significant decrease in growth fraction after IPR-treatment. From the results of this study it appears that β-adrenergic stimulation has an inhibitory effect on neonatal ileal epithelium.     

In Vitro Synthesis of Human Brain Proteins Including Tubulin and Actin by Purified Postmortem Polysomes

Abstract: Polysomes were prepared from human brain tissue 2-6 h postmortem; the polysomes were active in a cell-free protein synthesis system containing rabbit reticulocyte factors. Protein synthesis was totally dependent upon added MgCl₂, ATP, the reticulocyte factor fraction, and the human polysome fraction. Human brain proteins synthesized in the presence of L-[³⁵S]methionine were analyzed by one- and two-dimensional polyacrylamide gel electrophoresis. Over 250 proteins were synthesized and they extended in size up to 250,000 d; many of the most abundant native human brain proteins were synthesized, including tubulin and actin. It was shown that human brain α and β tubulin and actin isomers synthesized in vitro from human postmortem polysomes have the same apparent molecular weights and isoelectric points as the corresponding proteins synthesized by rat polysomes from fresh cortices. The corresponding tubulin and actin synthesized by human and rat brain polysomes also yield the same radioactive methionine-containing peptides after digestion with Staphylococcus aureus V8 protease. These analyses indicate that postmortem polysomes contain active messenger RNA which can direct the partial and/or complete synthesis of actin and tubulin subunits and other human brain proteins.     

Total Iron and Heme Iron Content and their Distribution in Beef Meat and Viscera

To determine the content of total iron (TFe) and heme iron (HeFe) in major cuts of meat and principal viscera of bovine origin. ⁵⁵Fe (30 mCi) was injected into two 4-month-old calves. Triplicate samples of the 12 basic American cuts of meat and major viscera were obtained from each specimen. Samples were acid digested and their iron content was read by atomic absorption spectrophotometry. Duplicate samples of the basic cuts of meat and major viscera were analyzed to determine the concentration of ⁵⁵Fe using a double isotopic technique. The mean and standard deviation of TFe for all cuts was 1.4?±?0.3 mg/100 g of meat. The mean TFe for organs was (per mg/100 g): 0.9?±?0.1 brain, 3.0?±?0.05 kidney, 3.2?±?0.04 heart, 5.7?±?0.2 lung, 6.0?±?0.1 liver, and 31.2?±?0.4 spleen. HeFe was 64% of TFe in meat and 72.8% in spleen, 53.8% in lung, 35.7% in brain, 35.0% in kidney, 27.3% in heart, and only 13.6% in liver. Blood contained 85.5% of the radioisotope and only 1.4% was found in muscle and 1.6% was found in viscera. Results suggest that bovine cuts of meat have a low variation in TFe and that HeFe comprises more than 60% of TFe.     

Composition, antimicrobial and antioxidant activity of the extracts of Eryngium palmatum Pančić and Vis. (Apiaceae)

The chemical composition, antimicrobial and antioxidant activity of Eryngium palmatum, an endemic plant species from the Balkan Peninsula, were investigated. The flavonoids apigenin (9.5±0.3 mg g^?1) and apigenin 7-O-glucoside (2.4±0.1 mg g^?1) were determined in a methanol extract of aerial parts using HPLC analysis. The methanol extract of roots contained catechin (5.0±0.1 mg g^?1), epicatechin (2.9±0.1 mg g^?1), chlorogenic acid (1.6±0.0 mg g^?1), gallic acid (0.9±0.0 mg g^?1) and rosmarinic acid (0.9±0.2 mg g^?1). GC-FID and GCMS analysis of a chloroform extract of aerial parts showed that the main volatile constituents were falcarinol, linoleic acid, hexadecanoic acid and methyl linoleate (comprising 32.6%; 24.4%; 19.9; 13.2% of the volatile fraction, respectively), while octanoic acid, tetradecanol and dodecanol dominated in the chloroform extract of the roots (34.9%; 25.8%; 22.2% of the volatile fraction, respectively). Investigation of antimicrobial activity by broth microdilution showed that the methanol and chloroform extracts of aerial parts and roots exerted a significant effect (MIC 3.5–15.6 μg mL^?1) against tested Gram-positive and Gram-negative bacteria. The methanol extracts of aerial parts or roots exerted moderate ferric reducing antioxidant power, DPPH radical scavenging activity and hydroxyl radical scavenging activity.     

早期经皮气管切开治疗原发性脑干出血的临床效果

目的:探讨早期经皮气管切开治疗原发性脑干出血中的临床效果。方法:选择2012年8月至2015年6月我院ICU收治的原发性脑干出血患者125例,按患者行气管切开的时间分组,以早期行气管切开(发病5 d内)定为观察组,发病5 d后行气管切开的患者定为对照组,对比两组患者的治疗效果。结果:两组患者的性别、年龄、APACHEII评分、GCS评分、疾病构成方面对比无明显差异(P0.05);观察组患者气管切开时机为(2.6±0.8)d,低氧血症发生的次数(20.6±5.5)次,镇静药物用量(132.8±23.4)mg,抗生素使用时间(11.2±0.9)d,机械通气时间(153.5±82.4)h,HAP发生率44.6%,病死率23.1%,均明显优于对照组患者,差异具有统计学意义(P0.05)。结论:早期气管切开有助于降低原发性脑干出血的死亡率,临床效果更好。     

心脏磁共振成像评价缺血性心肌病的临床应用价值

目的:评估心脏磁共振(cardiac magnetic resonance,CMR)功能成像在缺血性心肌病临床诊断中的价值。方法:使用飞利浦3.0T磁共振仪,对32例临床确诊的缺血性心肌病患者进行CMR平扫及钆对比剂动态增强扫描。应用Cardiac MR Analysis软件进行相关后处理分析,计算左室射血分数、室壁增厚率等心功能参数并与超声心动图检查结果相比较。采用17节段分段法分析心脏形态学、心肌组织运动、局部灌注、延迟增强等特点,评价其临床应用价值。结果:所有患者的心功能参数均降低,包括左室射血分数、每搏输出量、心输出量和室壁增厚率,心脏磁共振和超声心动图的测量结果并无明显差异(49%±5.3%vs 52%±8.2%;42.8 mL±8.9 mLvs 45.7 mL±10.6 mL; 3.5 L/min±0.6 L/min vs 3.8 L/min±0.9 L/min; 28%±4%. vs 31%±6%)(P0.05)。所有患者中存在室壁运动异常的为184段(184/544);其中心肌血流灌注信号减低的有136段(136/184),呈现心肌延迟强化的有98段(98/136)。结论:CMR功能成像对于缺血性心肌病的临床诊疗及预后评估可提供与心肌形态及功能相关的重要信息。     

Further characterization of a brain high molecular weight actin-binding protein (BABP): interaction with brain actin and ultrastructural studies

Crude actomyosin fraction from porcine brain contained a large amount of high molecular weight actin-binding protein (BABP). The molar ratio of BABP to actin (BABP/actin) in the fraction was estimated to be 0.22. From this fraction, BABP and actin were solubilized with a molar ratio of 0.25, suggesting the existence of an interaction between BABP and brain actin. BABP was finally purified to 90% purity. The purified BABP was negatively stained and observed by electron microscopy; it appeared to be a slender, flexible, two-stranded molecule whose contour length was about 200 nm. The structure was very similar to those of fodrin and other high molecular weight actin-binding proteins such as filamin, spectrin, and ABP. Lattice cage-like structures composed of BABP molecules were occasionally observed at high BABP concentrations. The addition of BABP to actin filaments resulted in the appearance of many branching, filamentous bundles. The electron microscopic observations suggested that a single BABP molecule could crosslink actin filaments, that is, one BABP molecule has two actin binding sites.     

Reduction of Serotonergic Function in Rat Brain by Tryptophan Depletion: Effects in Control and Fluvoxamine-Treated Rats

Abstract: The administration of tryptophan (Trp)-free amino acid mixtures to depressed patients responding to serotonin [5-hydroxytryptamine (5-HT)] uptake inhibitors (SSRIs) worsens their clinical state. This procedure reduces Trp availability to brain and thus impairs 5-HT synthesis. We have examined the influence of Trp depletion on extracellular 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the rat brain using in vivo microdialysis. The treatment with the SSRI fluvoxamine significantly increased 5-HT content in dialysates from frontal cortex, as compared with control rats (10.2 ± 2.7 vs. 3.1 ± 0.4 fmol per fraction), whereas 5-HIAA was unaffected. Food deprivation for 20 h reduced dialysate 5-HT content to almost control values in fluvoxamine-treated rats (10.2 ± 2.7 vs. 4.3 ± 0.6 fmol per fraction) but did not alter dialysate 5-HIAA content (7.8 ± 0.4 vs. 7.2 ± 0.5 pmol per fraction). The administration of Trp-free amino acid mixtures to fluvoxamine-treated rats significantly attenuated the release of 5-HT in frontal cortex (～50%) and, to a lesser extent, in the midbrain raphe nuclei. This effect was more marked in rats not deprived from food before the experiments (67% reduction of dialysate 5-HT content in frontal cortex) and was absent in control rats (treated with saline). In contrast, dialysate 5-HIAA was markedly affected by Trp depletion in all groups, including controls (65–75% reductions). These data show that the administration of an amino acid mixture with the same composition and dose (in milligrams per kilogram of body weight) as those inducing a severe mood impairment in depressed patients reduces 5-HT and 5-HIAA concentrations in brain dialysates. The reduction of 5-HT release, however, occurs only in animals previously treated with the antidepressant fluvoxamine for 2 weeks, which would be consistent with a marked reduction of 5-HT-mediated transmission in treated depressed patients but not in healthy controls.     

Effect of Hypothyroidism on Different Forms of Actin in Rat Cerebral Neuronal Cultures Studied by an Improved DNase I Inhibition Assay

An improved DNase I inhibition assay for the filamentous actin (F-actin) and monomeric actin (G-actin) in brain cells has been developed. Unlike other methods, the cell lysis conditions and postlysis treatments, established by us, inhibited the temporal inactivation of actin in the cell lysate and maintained a stable F-actin/G-actin ratio for at least 4-5 h after lysis. The new procedure allowed separate quantitation of the noncytoskeletal F-actin in the Triton-soluble fraction (12,000 g, 10 min supernatant) that did not readily sediment with the Triton-insoluble cytoskeletal F-actin (12,000 g, 10 min pellet). We have applied this modified assay system to study the effect of hypothyroidism on different forms of actin using primary cultures of neurons derived from cerebra of neonatal normal and hypothyroid rats. Our results showed a 20% increase in the Triton-insoluble cytoskeletal F-actin in cultures from hypothyroid brain relative to normal controls. In the Triton-soluble fraction, containing the G-actin and the noncytoskeletal F-actin, cultures from hypothyroid brain showed a 15% increase in G-actin, whereas the F-actin remained unaltered. The 10% increase in total actin observed in this fraction from hypothyroid brain could be totally accounted for by the enhancement of G-actin. The mean F-actin/G-actin ratio in this fraction was about 30% higher in the cultures from normal brain compared to that of the hypothyroid system, which indicates that hypothyroidism tends to decrease the proportion of noncytoskeletal F-actin relative to G-actin.     

Domestic use of a disclosing solution for denture hygiene: a randomised trial

doi:10.1111/j.1741‐2358.2009.00309.x
Domestic use of a disclosing solution for denture hygiene: a randomised trial Objectives: The purpose of this study was to investigate the effect of the domestic use of a disclosing agent for denture hygiene. Materials and methods: Completely edentulous participants wearing maxillary dentures were randomly assigned to one of the three intervention groups: (1) Follow‐up only (control; n = 12); (2) Oral and denture hygiene instructions (n = 10); (3) Instructions associated with the home use of a disclosing agent (1% neutral red; n = 10). Biofilm coverage area (%) over internal and external surfaces of the maxillary denture was assessed at baseline and after 14 and 90 days. Data were evaluated by generalised estimating equations based on score tests (α = 0.05). Results: The participants presented low changes for areas of biofilm coverage (14 days (%): internal: GI = 1.4 ± 0.9; GII = 1.5 ± 1.3; GIII = ?0.4 ± 0.9; external: GI = 1.4 ± 1.5; GII = 1.5 ± 1.4; GIII = ?0.4 ± 0.9; 90 days (%): internal: GI = 2.0 ± 0.9; GII = 2.2 ± 1.4; GIII = 0.3 ± 1.0; external: GI = 2.1 ± 1.4; GII = 2.2 ± 1.5; GIII = 0.3 ± 0.9). Changes were similar for the three groups (p = 0.293) and were not influenced by the test time (p = 0.218). Conclusion: It can be concluded that the home use of a disclosing agent for denture hygiene does not improve the removal of the biofilm, particularly for patients with adequate oral hygiene habits.     

Partial characterization of neuropathy target esterase and related phenyl valerate esterases from bovine adrenal medulla

The mechanism by which organo-phosphorus-induced delayed polyneuropathy is induced relates to the specific inhibition and subsequent modification (“aging”) of a protein known as neuropathy target esterase (NTE), operatively defined as paraoxon-resistant and mipafox-sensi-tive phenyl valerate (PV) esterase activity. This protein has fundamentally been investigated in hen brain, the latter being the habitually employed OPIDP study model. In the present article, a partial characterization is made of the NTE and other related PV esterases in the bovine adrenal medulla and brain; NTE sensitivity to the neurotoxic or-ganophosphorus compound mipafox is investigated, and its subcellular distribution is studied. The NTE activity of the adrenal medulla was found to be the highest of those among the tissues studied to date (5000 ± 1400 mU/g tissue; ± SD, n = 12). This activity represented 93% of the PV esterase activity resistant to 40 μm paraoxon in the par-ticulate fraction of the adrenal medulla and approximately 50% of total PV esterase activity. In the bovine brain, these proportions were 72 and 26%, respectively, i.e., similar to those described in hen brain. The mipafox inhibition curve of PV esterase activity resistant to 40μM paraoxon in the particulate fraction of the adrenal medulla suggests that NTE activity fundamentally comprises a mipafox-sensitive component with an I ₅₀ of 6.39 μM at 30 minutes, which is similar to the value reported in hen brain. NTE activity in the bovine adrenal medulla is almost exclusively limited to the particulate fraction, the microsomal fraction, plasma membrane, and chromaffin granule-enriched fractions being the highest in terms of specific activity. On the contrary, the mitochondria-enriched fraction was very poor in such activity. In bovine brain, most NTE activity was likewise limited to the particulate fraction.     

Effect of Resuscitation with 21% Oxygen and 100% Oxygen on NMDA Receptor Binding Characteristics Following Asphyxia in Newborn Piglets

The present study investigated the effect of reventilation with 21% and 100% oxygen following asphyxia in newborn piglets on NMDA receptor binding characteristics, Na⁺, K⁺-ATPase activity, and lipid peroxidation. After achieving a heart rate less than 60 beats per minute, asphyxiated piglets were reventilated with 21% oxygen or 100% oxygen. ³[H]MK-801 binding showed the Bmax in the 21% and 100% groups to be 1.53 ± 0.43 and 1.42 ± 0.35 pmol/mg protein (p = ns). Values for Kd were 4.56 ± 1.29 and 4.17 ± 1.05 nM (p = ns). Na⁺, K⁺-ATPase activity in the 21% and 100% groups were 23.5 ± 0.9 and 24.4 ± 3.9 μmol Pi/mg protein/h (p = ns). Conjugated dienes (0.05 ± 0.02 vs. 0.07 ± 0.03 μmol/g brain) and fluorescent compounds (0.54 ± 0.05 vs. 0.78 ± 0.19 μg quinine sulfate/g brain), were similar in both groups (p = ns). Though lipid peroxidation products trended higher in the 100% group, these data show that NMDA receptor binding and Na⁺, K⁺-ATPase activity were similar following reventilation with 21% or 100% oxygen after a single episode of mild asphyxia. Funded in part by a grant from the American Academy of Pediatrics/American Heart Association/Neonatal Resuscitation Program and NIH grant number HD-20337.     

Formulation,Optimization, Characterization,and Pharmacokinetics of Progesterone Intravenous Lipid Emulsion for Traumatic Brain Injury Therapy

Traumatic brain injury (TBI) is a major cause of mortality and disability throughout the world. Progesterone (PROG) plays an important role in neurologic treatment. The aim of this study was to develop a progesterone formulation with good physical and chemical stability. Progesterone intravenous lipid emulsion (PILE) was prepared based on one-factor-at-a-time experiments and orthogonal design. The optimal PILE was evaluated for mean particle size, particle size distribution, zeta potential, morphology, pH, osmolarity, entrapment efficiency, storage stability, and pharmacokinetics in ICR mice compared with the commercial progesterone products. The droplets of PILE had the smallest possible diameters of 218.0?±?1.8 nm and adequate zeta potential of ?41.1?±?0.9 mV. The volume percentage of droplets exceeding 5 μm (PFAT₅) of PILE was 0.003?±?0.0015% and much less than the specified standard. The TEM imaging proved that emulsion droplets had a smooth spherical appearance. Chemically and physically stable PILE was obtained with excellent entrapment efficiency that was up to 95.23%, with suitable pH at 7.15?±?0.01 and osmolarity at 301.3?±?1.2 mOsmol/l. Storage stability tests indicated that the emulsion was stable long term under ambient temperature conditions. Animal studies demonstrated that the emulsion was more effective with the higher progesterone concentration in the brain compared with commercial products. Therefore, the optimized PILE would offer great promise as a means of progesterone delivery for TBI therapy.     

Synthesis of Cytoskeletal Proteins in Bulk-Isolated Neuronal Perikarya Takashi Nakayama

Abstract: Neuronal perikarya were isolated from young rat brain by sucrose density gradient centrifugation of the tissue, dissociated with a low concentration of trypsin. The isolated cells retained their endogenous proteins, and were capable of active protein synthesis. After incubation with L-[³⁵S]methionine, perikarya were homogenised and separated into soluble and particulate fractions by centrifugation at 70,000 g. Newly synthesised polypeptides in each fraction were resolved by SDS-gel and two-dimensional gel electrophoresis coupled with fluorography. Neuronal perikarya synthesised predominantly actin, and α¹-, α² and β-tubulin. In addition, polypeptides with molecular weights of 35,000, 68,000 and 85,000 were heavily labelled. On two-dimensional electrophoresis, microheterogeneities were seen in soluble actin as well as in soluble tubulins, indicating that heterogeneities reported for brain actin and tubulins are inherent in neuronal actin and tubulins, but not owing to the heterogeneity of cells in the brain tissue. Structural differences between soluble tubulins and those associated with the particulate fraction were indicated by two-dimensional gel electrophoresis and also by one-dimensional peptide maps. The 68,000 molecular weight polypeptide synthesised in neuronal perikarya in vitro yielded a peptide map virtually identical with that generated from the major component of the neurofilament triplet polypeptides that were synthesised in situ. The 160,000 and 200,000 components of the neurofilament triplet were also synthesised in perikarya in vitro , but to disproportionately weaker extents compared with the 68,000 component.     

MICROHETEROGENEITY OF BRAIN CYTOPLASMIC AND SYNAPTOPLASMIC ACTINS

Abstract— Actin present in whole rat brain cytoplasm and in synaptosomes was purified by DNase I affinity chromatography. By use of two-dimensional gels and one-dimensional isoelectric focusing gels, brain actin was shown to be composed of two isomeric forms. By comparison with muscle actins, brain actins were identified as the β and γ isomers. Muscle type α actin is not present in brain. Synaptosomal protein with high affinity for DNase I is primarily composed of β and γ actin, however, two minor synaptosomal proteins, S₁ and S₂, with similar DNase I affinity were also isolated. S₁1 and S₂ have the same apparent molecular weight as whole brain actin, are more acidic than the major actin forms and are distinct from a actin. Relative to β and γ actin, the content of S₁ and S₂ is 3-fOld greater in synaptosomes when compared to similar non-synaptosomal species. The results demonstrate heterogeneity of brain actins and compartmentalization of brain proteins with high affinity for DNase I at the synapse. It was also shown that tubulin has selective affinity for the DNase I-actin complex.     

Actin and tubulin in normal and cystic fibrosis fibroblasts

Actin and tubulin contents of early passage, confluent human fibroblast cultures have been determined. Actin comprised 5.87 ± 0.81% of the total protein of IMR-90 fibroblasts which was not significantly different than the actin contents of two cystic fibrosis fibroblast cultures GM0142 and GM1348 (5.64 ± 0.90% of total protein). However, a significant difference between the amount of tubulin in IMR-90 fibroblasts (7.17 ± 0.25% of total protein) and the amount of tubulin in cystic fibrosis fibroblasts (4.51 ± 0.64% of total protein) was found.