Biomedical subjects

J Carlsson

Publications and source records attributed to J Carlsson.

At least 19 recordsLinked to original sources

PubMed1992

[Coronary stent implantation: a procedure for treatment of acute dissections after percutaneous transluminal coronary angioplasty].

The development of percutaneous wire-guided endoprostheses (stents) has expanded the possibilities for treating acute vascular occlusion within the field of coronary angioplasty (PTCA). A balloon-expandable Palmaz-Schatz stent was implanted in a total of 14 patients. The coronary arteries involved were the right coronary artery (seven cases), the anterior interventricular branch (five cases), and the circumflex branch (two cases). In seven cases the stent was inserted on an emergency basis to deal with treatening occlusion during PTCA, in one case of occlusion following coronary angiography, and in three cases to recanalize the infarcted vessel. Seven of these eleven patients were submitted to a follow-up angiography three months later, when none was shown to have a restenosis of more than 50%. Stent placement was followed by anticoagulation therapy comprising coumarin combined with acetylsalicylic acid. The Palmaz-Schatz stent represents an alternative to emergency bypass surgery in the treatment of acute dissection during PTCA.

Adult↗

PubMed1992

Influence of glucose on metabolism and growth of rat glioma cells (C6) in multicellular spheroid culture.

The metabolism and growth of rat glioma C6 cells in multicellular spheroid culture depended strongly on the glucose supply. A low glucose level (0.1 g/l) in the culture medium reduced lactate production, increased oxygen consumption and diminished hydrogen ion production under normoxia as well as hypoxia. A high glucose level (10 g/l glucose) increased lactate production, had no significant influence on oxygen consumption and increased the hydrogen ion production under hypoxia. Hydrogen ion release from cells under normoxic and hypoxic conditions could be significantly diminished by amiloride (l mM), indicating the involvement of the Na+/H+ exchanger. The growth of the C6 spheroids was enhanced under low glucose conditions, possibly due to the more physiological extracellular pH in the deeper regions of the spheroids. The growth was inhibited under high glucose conditions, which seemed to be toxic due to a massive hydrogen production giving acidosis. The glucose supply strongly influenced the local hydrogen ion production inside the C6 spheroids and this might in turn lead to changes in the response to different therapeutic modalities.

Animals↗

PubMed1992

Accumulation of 10B in the central degenerative areas of human glioma and colon carcinoma spheroids after sulfhydryl boron hydride administration.

Sulfhydryl boron hydride (BSH) (10B enriched) is presently used for boron neutron capture therapy of malignant gliomas. BSH must be close to the target cells to be effective in the inactivation of cell proliferation because of the short range of the reaction products (5-9 microns). Clinical experience indicates that BSH is taken up in gliomas but it is not known to which structures it binds at the cellular level. In vitro tests on monolayer cultured cells have indicated that BSH does not bind, or only shows very weak binding, to single isolated cells. It is possible that BSH accumulates in tumor regions due to the special conditions in poorly vascularized tumor tissue, such as low pO2, low extracellular pH, metabolic gradients, and degenerative changes. To test this we incubated three types of multicellular tumor spheroids with BSH for different times and analyzed both penetration and binding. The spatial distribution of 10B in sections of the spheroids was analyzed by neutron capture autoradiography. We found extensive accumulation of 10B in the central regions of both glioma and colon carcinoma spheroids. The accumulation closely followed the pattern of the degenerative changes which were characterized by massive necrosis in the central regions of the colon carcinoma spheroids and by a continuously increasing frequency of pyknotic nuclei as a function of depth in the glioma spheroids. The accumulation of 10B in the prostatic carcinoma spheroids was much lower. The penetration assay, based on freeze-drying and vapor fixation, showed that BSH penetrated easily since 10B equilibrated within 5-15 min in the studied spheroids. Thus, the low accumulation in the prostatic carcinoma spheroids was not due to penetration difficulties. The results of the present study on cellular spheroids and the results from previous studies on transplanted tumors support the observation that BSH penetrates easily into the degenerative tumor areas and that 10B, for some tumor types, might accumulate in these regions as a result of the BSH administration.

Autoradiography↗

PubMed1992

Radiation sensitization by estramustine studies on cultured human prostatic cancer cells.

In low-stage prostatic carcinoma, local cure can be obtained with radiation therapy alone, while in locally advanced disease the chances for cure are less. In this study, we have addressed the question of whether estramustine (EM), the main cytostatic metabolite of estramustine phosphate (Estracyt), may act as a radiosensitizing agent. This drug accumulates in prostatic cancer and has also been shown to arrest cancer cells at metaphase both in vitro and in vivo. The human prostatic cancer cell line DU 145 was grown as cultures monolayer and incubated with EM in concentrations varying from 1 to 20 micrograms/ml. External beam irradiation was performed with doses ranging from 0 to 8 Gy using gamma rays from a 60Co source. Clonogenic cell survival (CS) was used to analyse the radiation sensitizing effect of EM. The radiation dose modifying factor (DMF) at the survival level 0.1 was found to be 0.77 in the presence of EM (5 micrograms/ml), i.e., 23% sensitization was obtained. When irradiating cells at the standard fraction dose of 2 Gy in the absence of EM, 22% of the cells lost their clonogenic ability. In presence of EM (5 micrograms/ml), 2 Gy caused 40% of the cells to lose their clonogenic ability. Thus a radiation sensitizing effect of EM was established in the CS assay. It was also of interest to determine if the radiosensitizing effect of EM could be confirmed in a rapid assay. The rapid fluorescence assay was used to observe early damage of the cells. Results showed that by 2 days after exposure to irradiation a weak tendency towards sensitization was seen, while a clear sensitization was obtained after 4 days. This indicates that the rapid assay might be developed to a predictive assay for detection of the response of primary prostate tumor cells to the radiation sensitizing effect of EM.

Cell Survival↗

PubMed1992

Effects of EGF-dextran-tyrosine-131I conjugates on the clonogenic survival of cultured glioma cells.

Epidermal growth factor, EGF, and 131I or 125I-labelled tyrosine were conjugated to the sugar polymer dextran. The conjugates bound to EGF-receptor rich human glioma cells in culture and the binding was mainly receptor specific because cells presaturated with nonradioactive EGF gave strongly reduced binding. The 131I labelled conjugates were used in tests on cellular retention and therapeutical effects. 131I activity delivered to the cells as EGF-dextran-tyrosine-131I remained cell-associated for much longer periods of time than 131I activity delivered by only EGF. The amount of cell-associated 131I activity was nearly constant for up to 25 hours. The 131I labelled conjugate gave, after a one hour incubation period for binding followed by a 25 hour incubation in nonradioactive medium, a good therapeutical effect. This effect, which corresponded to about 3.0 Gy of external 60Co radiation, was due to the specifically bound 131I. The comparatively small effects of nonbound 131I in the culture medium, present only during the first incubation hour, were measured in control experiments with presaturated receptors and were corrected for in the evaluation of the EGF-receptor mediated effects. Control experiments showed that neither nonradioactive EGF nor non-radioactive EGF-dextran conjugates gave measurable effects on clonogenic growth. The results obtained were promising and the possibilities to use EGF-dextran conjugates for therapy should be further examined.

Brain Neoplasms↗

PubMed1992

Relations between the penetration, binding and average concentration of cytostatic drugs in human tumour spheroids.

A penetration assay based on freeze-drying and vapour fixation was applied to show the spatial distribution of non-bound and bound cytostatic drugs in cellular spheroids. Several studies have proposed that peripheral binding of drugs correlates with limited penetration. We showed that granular accumulation, mainly at the peripheral part of spheroids, might occur in parallel with good penetration. For example, this was the case in human glioma spheroids after incubation with Adriamycin for 15-30 min. Following treatment with actinomycin D, colon carcinoma spheroids exhibited rather good penetration but also showed granular accumulation mainly in their peripheral regions. Ara-C accumulated largely and homogeneously in the peripheral regions of colon carcinoma spheroids and this severely delayed penetration. It took about 1 h for ara-C in the central regions of the spheroids to reach the same concentration as in the culture medium. In contrast, ara-C easily penetrated glioma spheroids without accumulating noticeably at the periphery. Retention tests involving washing and further incubation in drug-free culture medium revealed that the areas demonstrating extensive accumulation most often retained the drug, indicating binding, whereas the concentration of drug in other areas decreased. The oil-centrifugation method, which was used for rapid separation of the spheroids from the drug-containing medium, showed that the average concentration of daunomycin in the spheroids exceeded that in the culture medium as early as after 15 min, by which time only limited penetration had occurred. We found that good penetration of ara-C correlated with a low average concentration in glioma spheroids, whereas limited penetration correlated with a high average concentration in colon carcinoma spheroids. The latter finding was attributable to the high accumulation of drug at the spheroid periphery. Thus, there was an inverse relationship between penetration and binding and between penetration and average drug concentration. It seemed that binding delayed or prevented penetration, whereas little, if any binding resulted in better penetration. Granular binding such as that observed Adriamycin and actinomycin D gave intermediately good penetration.

Antineoplastic Agents↗

PubMed1992

Malaria and the red cell membrane.

Malarial parasites are primarily parasites of red cells and during infection ingest most of the haemoglobin within these cells, leaving the membrane as the only vestige of the original host cell. The red cell membrane thus plays a key role at all stages of infection with malarial parasites, and is modified in many ways during parasitisation, so that at least functionally it has little resemblance to the membrane from which it was originally derived. The highly specific and ordered process of parasite invasion of red cells is regulated at least in part by the uninfected red cell membrane. The red cell sialoglycoproteins or glycophorins of this membrane have been shown to play an important role in invasion by Plasmodium falciparum, the species of most importance to man because of it's high morbidity and mortality. Structurally, dynamic changes occur within the membrane during parasitisation, and a number of parasite proteins have been found to be associated within it, but changes on the surface of the infected cell have been more difficult to demonstrate. The membrane of the infected cell is important in the many metabolic processes of the parasite, as well as the critical cell-cell interactions that occur when cells containing mature parasites bind to endothelial cells (cytoadherence), bind to uninfected cells (rosetting), or interact with macrophages and other leucocytes. The recognition molecules on the red cell membrane involved in invasion, cytoadherence and rosetting appear to be quite distinct. Structural and functional changes have also been shown to occur in the membranes of uninfected red cells, both in infected patients, and in the presence of parasites in vitro. Interactions of the parasite P. falciparum with the red cell membrane hold the key to our understanding of the pathogenesis of severe falciparum infection in man.

Animals↗

PubMed1992

Strategy for planned radiotherapy of malignant gliomas: postoperative treatment with combinations of high dose proton irradiation and tumor seeking radionuclides.

A strategy for improved treatment of malignant gliomas grade III-IV is presented. The strategy can briefly be described as surgical removal of the bulky tumor, high precision external irradiation of small brain volumes over and near the primary tumor area with high doses from proton beams, and thereafter treatment of spread cells with toxic radionuclides. Proton beams suitable for this are under development. The clinical effects of high single doses on malignant gliomas grade III-IV are presently tested with conventional gamma radiation. Targeting of spread glioma cells with toxic radionuclides tagged to epidermal growth factor, EGF, or to EGF-dextran is presently tested in experimental systems and can, in the near future, be tested in combination with local high doses of external proton radiation. The possibilities to combine proton beams with EGF-guided neutron capture therapy will be considered in a longer perspective.

Brain Neoplasms↗

PubMed1992

The effect of additional feeding on the fertility of high-yielding dairy cows.

One hundred and ninety three pairs of cows were selected from 38 herds, and the numbers of each pair were assigned at random to experimental and control groups. Each control cow was fed according to its yield with the feedstuffs normally used by the herd. Each experimental cow was fed in the same way and, in addition, received 500 g of a feed additive twice daily from the 40th day of lactation until first insemination or to the 75th day of lactation if no visible oestrus had been observed between days 40 and 75. One kg of the feed additive contained glucogenic substances (glycerol and Ca-propionate) equivalent to 1.90 moles of glucose, 13.6 MJ metabolizable energy, and 180 g digestible crude protein. There were no significant differences between the groups with respect to their mean daily milk yield, their plasma glucose concentrations at first insemination, or the interval between calving and first insemination. However, the experimental cows had a significantly shorter interval between calving and last insemination (mean difference 11.0 days). The pregnancy rate was significantly higher among cows with high than among cows with low plasma glucose concentrations. There was also a tendency towards a reduced pregnancy rate among cows with either high (greater than 7.0 mmol/litre) or low (less than 4.0 mmol/litre) milk urea concentrations.

Animal Feed↗

PubMed1992

Present status of boron neutron capture therapy.

The neutron capture reaction 10B(1n,4He)7Li produces two energetic particles, 4He2+ and 7Li3+ that are strongly cell toxic. Due to the short range of these nuclear fragments (5-9 microns) mainly those cells that have bound or internalized a 10B-containing substance are growth-inactivated. The most critical and difficult step in an efficient boron neutron capture therapy (BNCT) is the tumour targeting. It is today possible to synthesize a large number of boron compounds and conjugate them to tumour-seeking macromolecules, such as monoclonal antibodies or different polypeptides. The boron-containing substances presently considered for therapy are sulfhydryl boron hydride (BSH) and boron-phenylalanine, (BPA) for the treatment of gliomas and malignant melanomas respectively. Other boronated compounds considered are ligands for receptor-amplified tumour cells, antibodies for tumour cells with specific antigens and thioureas for treatment of melanotic melanomas. The required boron concentration is given by the relative dose due to neutron capture in 10B and that of the competing capture reactions in nitrogen and hydrogen. Capture in nitrogen produces protons with a range of about 10-11 microns and this gives a radiation dose to all cells in the neutron activated area. Calculations show that the local concentration of 10B near the critical radiation target, DNA, must be higher than 10 ppm (10 micrograms/g). Increased emphasis will be put on the development of combinations of treatments that fulfil the requirements for attacking the microscopic spread of the tumour.

Boron↗

PubMed1992

Thrombolysis using consecutive high dose bolus and infusion of alteplase in a patient with acute massive pulmonary embolism.

We describe the successful use of a novel dosage regimen of alteplase in a 77-year-old man with massive acute pulmonary embolism in the presence of a relative contraindication (recent cranial surgery). An intravenous alteplase bolus of 50 mg was administered, followed 40 min later by a 50 mg infusion over 2 h. Pulmonary arteriography showed a considerable increase in intraluminal filling of thrombotically occluded vessels as a result of alteplase administration, and was accompanied by marked clinical improvement. Peak alteplase plasma concentration after the bolus was 5.5 micrograms/ml, and the steady state concentration during infusion was 0.52 micrograms/ml. Detailed monitoring of haemostasis parameters showed elevated endogenous fibrinolytic activity at baseline, very high levels of fibrin degradation products during treatment resulting from lysis of an extensive thrombus mass, moderate fibrinogenolysis compared to fibrinolysis, long plasma half-lives of fibrin(ogen) degradation products (9.2-11.0 h), and increased thrombin generation. There were no bleeding side-effects. The regimen combines the advantages of rapid onset (bolus) and maintained potency (infusion) of thrombolytic effect in pulmonary embolism.

Aged↗

PubMed1992

Induction and quantification of hepatic metastases from a human colonic cancer in the nude rat.

Nude rats were injected with human colonic cancer cells (LS 174 T) in the superior mesenteric vein and the extent of hepatic metastases at sacrifice was estimated by visual inspection and computer-based area calculation. After 3 weeks, 5.0 x 10(6) cells caused hepatic metastases in 14/14 rats whereas 0.5 x 10(6) cells failed to produce liver metastases in 4/4 rats (P < 0.001). Injection of 1.0 x 10(7) cells caused portal vein occlusion in 3/5 rats. Extrahepatic tumour growth was rare; lung metastases were observed in four rats, and three rats had local tumour in the abdomen. The average extent of hepatic tumour replacement was 20.2 +/- 4.0%. Injection of embolies or single cells did not affect the incidence or extent of hepatic metastases. The incidence of hepatic metastases was similar in male and female rats, but the extent of hepatic tumour was larger in males (24.6%) than in females (3.2%) (P = 0.005). The pathophysiological similarities to human disease should make this model suitable for diagnostic and therapeutic studies with clinical application.

Animals↗

PubMed1991

Clinical relevance of the quantification of apolipoprotein E in cerebrospinal fluid.

Apolipoprotein E was measured in paired sera and cerebrospinal fluid samples from 483 neurological patients. The average apolipoprotein E concentration was 7.5 (+/- 3.1) mg/l in cerebrospinal fluid and 93.5 (+/- 29.7) mg/l in serum. Mean apolipoprotein B concentrations in 88 patients were 0.77 +/- 3.4 mg/l in cerebrospinal fluid and 1.06 +/- 0.31 g/l in serum. The apolipoprotein E concentration in cerebrospinal fluid was much greater than expected for passive diffusion from serum. By contrast to apolipoprotein B, there was no correlation between the apolipoprotein E cerebrospinal fluid/serum concentration quotient and the albumin concentration quotient. This suggests that apolipoprotein E in cerebrospinal fluid, unlike apolipoprotein B, is locally synthesized and that the use of a cerebrospinal fluid/serum concentration quotient is unnecessary. In a control group (n = 64) the mean cerebrospinal fluid apolipoprotein E value (+/- SD) was 5.9 (1.6) mg/l. Elevated cerebrospinal fluid apolipoprotein E concentrations were observed in acute (n = 22, 12.5 +/- 6.2 mg/l) and chronic inflammatory central nervous system diseases (n = 15, 10.4 +/- 2.4 mg/l).

Adult↗

PubMed1991

Binding of epidermal growth factor-dextran conjugates to cultured glioma cells.

Some gliomas, melanomas and squamous carcinomas have large numbers of EGF receptors which could, in these cases, be used for targeting with toxic agents. We investigated whether EGF could be conjugated to dextran, which is a suitable carrier for toxic agents, without losing its ability to bind to the receptor. Dextran of 20 kDa molecular weight was activated with I-cyano-4-dimethylamino pyridinium tetrafluoroborate (CDAP) yielding highly active pyridinium-isourea derivatives. EGF was coupled to the activated dextran through the amino terminus and glycine was added to block residual activity. The EGF-dextran conjugate was, after purification on Sephadex G25 and Sephacryl 200 columns, tested for its receptor binding properties on human malignant glioma, U343MGaC12:6, cells. The conjugate inhibited binding of 125I-EGF in a competitive assay, showing that the binding was receptor-specific. Dextran conjugated with glycine, without EGF, had no inhibitory effect. The conjugate was radio-labelled either on the EGF part with 125I or on the dextran part with 3H-glycine, and the internalization patterns were compared to the internalization of 125I-EGF. The radioactivity of the conjugates remained cell-associated for more than 20 hr, regardless of whether the radioactivity was on the EGF or on the dextran part, while the radioactivity of unconjugated EGF rapidly disappeared from the cells. Most of the cell-associated radioactivity was, at all analysed time intervals, located intracellularly. Thus, it seems promising to use dextran, conjugated with EGF, as a carrier of, for example, toxic radioactive nuclides.

Dextrans↗

PubMed1991

Effects of amiloride treatment on U-118 MG and U-251 MG human glioma and HT-29 human colon carcinoma cells.

Human glioma (U-118 MG, U-251 MG) and human colon carcinoma (HT-29) spheroids and monolayers were continuously exposed to amiloride under physiological Na+ and HCO3- conditions. Amiloride in concentrations of 0.1-0.2 mM inhibited growth, while 0.5 mM or higher induced disintegration of the glioma spheroids within 4-6 days. Growth retardation of the HT-29 spheroids was achieved at concentrations of 0.4-0.5 mM and total growth inhibition and disintegration were achieved at 1.0 mM. Monolayer cultures of glioma cells were also more sensitive to amiloride than those of colon carcinoma cells. The higher amiloride concentrations induced pyknotic nuclei mainly in the central areas of the spheroids where the extracellular pH (pHe) was low. The amiloride-sensitive glioma spheroids had lower pHe than the colon carcinoma spheroids. The intracellular pH (pHi), measured in monolayers, was higher (7.11-7.18) in glioma cells than in colon carcinoma cells (6.94). High concentrations of amiloride, 1.0 mM for 1 h in combination with low Na+ concentrations, caused a strong pHi decrease in glioma cells but only a slight decrease in the colon carcinoma cells. The pHi measurements in glioma monolayers were carried out after 2-6 days of continuous exposure to 0.1 mM amiloride at physiological levels of Na+ and HCO3- to simulate the conditions during growth inhibition. After several days this caused, when growth already was inhibited, an acidification of pHi. Parallel measurements with X-ray microanalysis showed an increase of intracellular sodium and a decrease of intracellular potassium in the gliomas, while no such changes were seen in the colon carcinoma cells under identical conditions. It is concluded that the two glioma cell lines were more sensitive to amiloride, both as monolayers and spheroids, than the corresponding cultures of the colon carcinoma cell line. The inhibition of proliferation by amiloride seemed not to have a clear connection to pHi regulation.

Amiloride↗

PubMed1991

Studies on Pf155/RESA and other soluble antigens from in vitro cultured Plasmodium falciparum.

Spent culture medium from in vitro cultures of Plasmodium falciparum was used as the source for immunoadsorbent enrichment of soluble parasite antigens. IgG obtained from P. falciparum-hyperimmune Liberian serum was used as the ligand in the immunoadsorbent. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the immunoadsorbent isolated material revealed the presence of at least 15 antigenic and parasite-derived polypeptides. Immunoblotting after SDS-PAGE showed greater than 20 antigenic polypeptides in the molecular weight range of 15-250 kDa. Several of these were heat-stable (100 degrees C for 5 min), and six of them were detected even after heating for 60 min. Among the latter antigens was Pf155/RESA, a merozoite antigen deposited in the erythrocyte membrane at invasion. Pf155/RESA can be detected using a modified erythrocyte membrane immunofluorescence (EMIF) assay. Inhibition of EMIF with heated parasite material showed that the antigenic activity was intact after heating for up to 30 min. The immunofluorescence-inhibitory activity was separated into two fractions, one containing Pf155/RESA and one containing polypeptides with molecular weights of 135 and 120 kDa. All three of these antigenic polypeptides bound selectively, albeit nonspecifically, to aminoethyl-BioGel resins.

Animals↗

PubMed1991

Heterogeneity in antigenic expression and radiosensitivity in human colon carcinoma cell lines.

A panel of human colon carcinoma cell lines were characterized regarding both antigenic heterogeneity and variations in radiosensitivity. Monoclonal antibodies were used to study the expression of carcinoembryonic antigen (CEA), gastrointestinal cancer antigen (GICA or CA 19-9) and carcinoma-associated antigen (CA-50). Radiosensitivity was studied with the clonogenic survival technique. Three cell lines, LS 174T, HCTC, and SW 1116 stained positive for all three antigens. HT-29 was positive for CA 19-9 and CA-50 whereas Caco-2 was positive for CEA and CA 19-9. The cell lines SW 620 and LIM 1215 only stained positive for one of the antigens, CA-50 and CEA, respectively. In nearly all positive cases the stainings were very heterogeneous with mixtures of positive and negative cells. One exception was the HCTC cells which stained homogeneously for the CA 19-9 and CA-50 antigens. The neuroendocrinelike COLO 320 cells were negative in all cases. The radiosensitivity varied strongly between the cell lines with Dq-values between 0.8 and 1.9, extrapolation numbers between 2.0 and 4.7, Do-values between 1.1 and 2.8. The surviving fraction at 2 Gy varied between 0.3 and 0.7 with HCTC as the most radiosensitive and HT-29 as the most radioresistant cell line. Thus, there were differences in antigenic expression and intrinsic radiosensitivity between the cell-lines and antigenic heterogeneities within each cell line. The analyzed panel of cell lines will be valuable in studies of dose-effect relations for monoclonal antibodies labeled with toxic radionuclides simulating both antigenic heterogeneity and variations in radiosensitivity.

Adenocarcinoma↗

PubMed1991

Plasmodium falciparum: analysis of the interaction of antigen Pf155/RESA with the erythrocyte membrane.

The location of the Plasmodium falciparum vaccine candidate antigen Pf155/RESA in the membrane of infected erythrocytes was analzyed by means of selective surface radioiodination and immunofluorescence of surface-modified cells. The lack of radiolabel in Pf155/RESA as well as its localization by immunofluorescence similar to that of the N-terminal region of erythrocyte band 3 suggests that the antigen is associated with the cytoplasmic phase of the erythrocyte membrane. In concordance with this, Pf155/RESA was detected by immunofluorescence on the surface of inside out membrane vesicles from P. falciparum-infected erythrocytes. Pf155/RESA from spent culture medium also bound to inside out membrane vesicles of normal erythrocytes as well as to cytoskeletal shells of such vesicles, but failed to bind to sealed right-side out membrane vesicles. Depletion of spectrin from the vesicles abolished antigen binding, suggesting that Pf155/RESA association with the erythrocyte cytoskeleton is mediated by spectrin.

Amino Acid Sequence↗