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PubMed2000

Activation of p53 or loss of the Cockayne syndrome group B repair protein causes metaphase fragility of human U1, U2, and 5S genes.

Infection by adenovirus 12, transfection with the Ad12 E1B 55 kDa gene, or activation of p53 cause metaphase fragility of four loci (RNU1, PSU1, RNU2, and RN5S) each containing tandemly repeated genes for an abundant small RNA (U1, U2, and 5S RNA). We now show that loss of the Cockayne syndrome group B protein (CSB) or overexpression of the p53 carboxy-terminal domain induces fragility of the same loci; moreover, p53 interacts with CSB in vivo and in vitro. We propose that CSB functions as an elongation factor for transcription of structured RNAs, including some mRNAs. Activation of p53 would inhibit CSB, stalling transcription complexes and locally blocking chromatin condensation. Impaired transcription elongation may also explain the diverse clinical features of Cockayne syndrome.

Acetylation↗
PubMed1999

Min-21 and min-23, the smallest peptides that fold like a cystine-stabilized beta-sheet motif: design, solution structure, and thermal stability.

Small disulfide-rich proteins provide examples of simple and stable scaffolds for design purposes. The cystine-stabilized beta-sheet (CSB) motif is one such elementary structural motif and is found in many protein families with no evolutionary relationships. In this paper, we present NMR structural studies and stability measurements of two short peptides of 21 and 23 residues that correspond to the isolated CSB motif taken from a 28-residue squash trypsin inhibitor. The two peptides contain two disulfide bridges instead of three for the parent protein, but were shown to fold in a native-like fashion, indicating that the CSB motif can be considered an autonomous folding unit. The 23-residue peptide was truncated at the N-terminus. It has a well-defined conformation close to that of the parent squash inhibitor, and although less stable than the native protein, it still exhibits a high T(m) of about 100 degrees C. We suggest that this peptide is a very good starting building block for engineering new bioactive molecules by grafting different active or recognition sites onto it. The 21-residue peptide was further shortened by removing two residues in the loop connecting the second and third cysteines. This peptide exhibited a less well-defined conformation and is less stable by about 1 kcal mol(-)(1), but it might be useful if a higher flexibility is desired. The lower stability of the 21-residue peptide is supposed to result from inadequate lengths of segments connecting the first three cysteines, thus providing new insights into the structural determinants of the CSB motif.

Amino Acid Sequence↗
PubMed1997

Sequence-specific and domain-specific DNA repair in xeroderma pigmentosum and Cockayne syndrome cells.

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) cells have specific DNA repair defects. We had previously analyzed repair rates of cyclobutane pyrimidine dimers at nucleotide resolution along the human JUN gene in normal fibroblasts and found very efficient repair of sequences near the transcription initiation site but slow repair along the promoter. To investigate sequence-specific repair rate patterns in XP and CS cells, we conducted a similar analysis in XPA, XPB, XPC, XPD, and CSB fibroblasts. XPA cells were almost completely repair-deficient at all sequences analyzed. XPC cells repaired only the transcribed DNA strand beginning at position -20 relative to the transcription start site. Both XBP and XPD cells were deficient in repair of nontranscribed DNA and also very inefficiently repaired the transcribed strand including sequences near the transcription start site. CSB cells exhibited rapid repair near the transcription initiation site but were deficient in repair of sequences encountered by RNA polymerase during elongation (beginning at position +20). Since transcription of the JUN gene was UV-induced in all fibroblast strains, including CSB, the defective repair of the transcribed strand in CSB cannot be explained by a lack of transcription; rather, it appears to be a true DNA repair defect.

Base Sequence↗
PubMedDate not supplied

Viability and acrosome staining of stallion spermatozoa by Chicago sky blue and Giemsa.

A simple trypan blue-neutral red-Giemsa staining procedure for simultaneous evaluation of acrosome, sperm head, and tail membrane integrity and morphology has been used to evaluate equine spermatozoa. Some special characteristics and problems have arisen in evaluating stallion semen. One problem was the differentiation of intact vs. damaged sperm tails primarily in frozen and thawed samples. After freezing and thawing, a high percentage of spermatozoa with an unstained head and stained tail were observed. These cells are considered immotile. Therefore, unambiguous differentiation of intact vs. damaged sperm tail membrane is very important for evaluating semen quality. The aim of our study was to develop a method especially for stallion sperm to distinguish more accurately the different cell types. We compared Chicago sky blue 6B (CSB) to trypan blue (TB) for viability staining. CSB/Giemsa staining showed good repeatability and agreement with TB/Giemsa measurements. For densitometry analysis, individual digital images were taken from smears stained by CSB/Giemsa and by TB/Giemsa. A red-green-blue (RGB) histogram for each area of spermatozoa was drawn. Differences of means of RGB values of live vs. dead tails and separate live vs. dead heads from each photo were used to compare the two staining procedures. CSB produced similar live/dead sperm head differentiation and better tail differentiation. TB can be replaced by CSB and this results in more reliable evaluation. After staining with 0.16% CSB and 4 min fixation, 2-4 h Giemsa staining at 25-40 degrees C is recommended for stallion semen.

Acrosome↗
PubMed2001

Expression of a Pseudomonas aeruginosa citrate synthase gene in tobacco is not associated with either enhanced citrate accumulation or efflux.

Aluminum (Al) toxicity and poor phosphorus (P) availability are factors that limit plant growth on many agricultural soils. Previous work reported that expression of a Pseudomonas aeruginosa citrate synthase gene in tobacco (Nicotiana tabacum; CSb lines) resulted in improved Al tolerance (J.M. de la Fuente, V. Ramírez-Rodríguez, J.L. Cabrera-Ponce, L. Herrera-Estrella [1997] Science 276: 1566-1568) and an enhanced ability to acquire P from alkaline soils (J. López-Bucio, O. Martínez de la Vega, A. Guevara-García, L. Herrera-Estrella [2000] Nat Biotechnol 18: 450-453). These effects were attributed to the P. aeruginosa citrate synthase increasing the biosynthesis and efflux of citrate from roots. To verify these findings we: (a) characterized citrate efflux from roots of wild-type tobacco; (b) generated tobacco lines expressing the citrate synthase gene from P. aeruginosa; and (c) analyzed selected CSb lines described above. Al stimulated citrate efflux from intact roots of wild-type tobacco and root apices were found to be responsible for most of the efflux. Despite generating transgenic tobacco lines that expressed the citrate synthase protein at up to a 100-fold greater level than the previously described CSb lines, these lines did not show increased accumulation of citrate in roots or increased Al-activated efflux of citrate from roots. Selected CSb lines, similarly, failed to show differences compared with controls in either citrate accumulation or efflux. We conclude that expression of the P. aeruginosa citrate synthase gene in plants is unlikely to be a robust and easily reproducible strategy for enhancing the Al tolerance and P-nutrition of crop and pasture species.

Citrate (si)-Synthase↗
PubMed2003

Cardiovascular regulation in the period preceding vasovagal syncope in conscious humans.

To study cardiovascular control in the period leading to vasovagal syncope we monitored beat-to-beat blood pressure, heart rate (HR) and forearm blood flow in 14 patients with posturally related syncope, from supine through to tilt-induced pre-syncope. Signals of arterial blood pressure (BP) from a Finapres photoplethysmograph and an electrocardiograph (ECG) were fed into a NeuroScope system for continuous analysis. Non-invasive indices of cardiac vagal tone (CVT) and cardiac sensitivity to baroreflex (CSB) were derived on a beat-to-beat basis from these data. Brachial vascular resistance (VR) was assessed intermittently from brachial blood flow velocity (Doppler ultrasound) divided by mean arterial pressure (MAP). Patients underwent a progressive orthostatic stress test, which continued to pre-syncope and consisted of 20 min head-up tilt (HUT) at 60 deg, 10 min combined HUT and lower body suction (LBNP) at -20 mmHg followed by LBNP at -40 mmHg. Pre-syncope was defined as a fall in BP to below 80 mmHg systolic accompanied by symptoms. Baseline supine values were: MAP (means +/- S.E.M.) 84.9 +/- 3.2 mmHg; HR, 63.9 +/- 3.2 beats min-1; CVT, 10.8 +/- 2.6 (arbitrary units) and CSB, 8.2 +/- 1.6 ms mmHg-1. HUT alone provoked pre-syncope in 30 % of the patients whilst the remaining 70 % required LBNP. The cardiovascular responses leading to pre-syncope can be described in four phases. Phase 1, full compensation: where VR increased by 70.9 +/- 0.9 %, MAP was 89.2 +/- 3.8 mmHg and HR was 74.8 +/- 3.2 beats min-1 but CVT decreased to 3.5 +/- 0.5 units and CSB to 2.7 +/- 0.4 ms mmHg-1. Phase 2, tachycardia: a progressive increase in heart rate peaking at 104.2 +/- 5.1 beats min-1. Phase 3, instability: characterised by oscillations in BP and also often in HR; CVT and CSB also decreased to their lowest levels. Phase 4, pre-syncope: characterised by sudden decreases in arterial blood pressure and heart rate associated with intensification of the symptoms of pre-syncope. This study has given a clearer picture of the cardiovascular events leading up to pre-syncope. However, the mechanisms behind what causes a fully compensated system suddenly to become unstable remain unknown.

Adult↗
PubMed1997

Recruitment of the putative transcription-repair coupling factor CSB/ERCC6 to RNA polymerase II elongation complexes.

Cockayne's syndrome (CS) is a disease characterized by developmental and growth defects, sunlight sensitivity, and a defect in transcription-coupled nucleotide excision repair. The two principle proteins involved in CS, CSA and CSB/ERCC6, have been hypothesized to bind RNA polymerase II (Pol II) and link transcription to DNA repair. We have tested CSA and CSB in assays designed to determine their role in transcription-coupled repair. Using a unique oligo(dC)-tailed DNA template, we provide biochemical evidence that CSB/ERCC6 interacts with Pol II molecules engaged in ternary complexes containing DNA and nascent RNA. CSB is a DNA-activated ATPase, and hydrolysis of the ATP beta-gamma phosphoanhydride bond is required for the formation of a stable Pol II-CSB-DNA-RNA complex. Unlike CSB, CSA does not directly bind Pol II.

Adenosine Triphosphatases↗
PubMed1998

Central interaction between carotid baroreceptors and skeletal muscle receptors inhibits sympathoexcitation.

To determine the potential of an inhibitory interaction between the carotid sinus baroreflex (CSB) and the exercise pressor reflex (EPR), both pathways were activated to produce sympathoexcitation. It was hypothesized that, under conditions when the baroreflex increased sympathetic outflow, the interaction between CSB and EPR would be inhibitory. Bilateral carotid occlusion (BCO), electrically induced muscle contraction (EMC), and passive muscle stretch (PMS) were used to evoke sympathoexcitation. BCO decreased sinus pressure 50 +/- 5 mmHg, and the levels of muscle tension generated by EMC and PMS were 7 +/- 2 and 8 +/- 1 kg, respectively. This resulted in significant increases in mean arterial pressure (MAP) of 55 +/- 9, 50 +/- 7, and 50 +/- 6 mmHg (P = not significant, BCO vs. EMC vs. PMS) and in heart rate (HR) of 7 +/- 2, 19 +/- 4, and 17 +/- 2 beats/min (P < 0. 05, BCO vs. EMC and PMS). When BCO was combined with EMC or PMS, the reflex increase in MAP was augmented (80 +/- 8 and 79 +/- 10 mmHg; BCO+EMC and BCO+PMS, respectively; P < 0.05). However, summation of the individual MAP responses was greater than the response evoked during coactivation (106 +/- 11 and 103 +/- 12 mmHg, respectively, P < 0.05). Because summing the individual blood pressure responses exceeded the response during coactivation, the net effect was that the CSB and EPR interacted in an occlusive manner. In contrast, summation of the individual chronotropic responses was the same as the response evoked during coactivation. Moreover, there was no difference in summation of the individual MAP or HR responses when muscle afferents were activated by either EMC or PMS. In conclusion, the interaction between the CSB and the EPR in control of MAP was occlusive when both reflexes were stimulated to evoke sympathoexcitation. However, summation of the reflex changes in HR was simply additive.

Animals↗
PubMed2004

Donated fortified cereal blends improve the nutrient density of traditional complementary foods in Haiti, but iron and zinc gaps remain for infants.

This research assesses whether fortified cereal blends such as corn-soy blend (CSB) or wheat-soy (WSB) blend can significantly contribute to improving the quality of the diet of infants and young children 6 to 23 months of age. A series of participatory recipe trials was conducted to assess current complementary feeding practices in the Central Plateau of Haiti and to develop new, improved recipes by using a combination of locally available ingredients and foods and donated fortified cereal blends. Our findings show that it is feasible to improve the nutritional quality of complementary foods in poor rural areas of Haiti, using locally available ingredients and fortified cereal blends. Significant improvements in the concentrations of vitamin A could be obtained by including acceptable and affordable amounts of locally available vitamin A-rich foods such as pumpkin or eggs. Only preparations using CSB, however, could achieve the recommended concentrations of iron and zinc in complementary foods, and even this was achievable only for 12- to 23-month-old children. For infants, and especially those between 6 and 8 months of age, the high requirements of 7.7 mg of iron and 1.6 mg of zinc per 100 kcal of complementary foods could not be met, even with a combination of fortified CSB and other locally available, acceptable, and affordable foods. The same was true for the zinc density of complementary foods among 9- to 11-month-old children, which could not be achieved even with fortified CSB. Thus, in this population, fortified cereal blends were key to achieving the recommended iron and zinc densities of complementary foods for children 12 to 23 months of age, but they were not sufficient for infants. Complementary approaches, such as improving the availability, access, and intake of animal-source foods or the use of home fortification techniques (using spreads, sprinkles, or dispersible tablets), are needed to ensure adequate iron and zinc density of complementary foods for infants younger than 12 months in resource-constrained environments such as rural Haiti.

Edible Grain↗
PubMed2002

Supplemental betaine and peroxide-treated feather meal for finishing cattle.

These studies evaluated the effects of betaine, provided either as feed-grade betaine or as concentrated separator by-product (CSB; desugared beet molasses), on performance and carcass characteristics of finishing cattle. In Exp. 1, 175 steers (410 kg initial BW) were fed a finishing diet based on steam-flaked and dry-rolled corn, and treatments included 10.5 and 21 g/d feed-grade betaine and 250 and 500 g/d CSB (supplying 15.5 and 31 g/d of betaine, respectively). Steers fed feed-grade betaine had greater (linear and quadratic effects, P < 0.1) DMI than control steers, but ADG and gain efficiencies were not affected by treatment. Dressing percent and backfat thickness was greater (P < 0.1) for steers that received feed-grade betaine than for controls. Longissimus muscle area was lower (P < 0.1) for steers supplemented with either feed-grade betaine or CSB than for control steers. Yield grades were higher for cattle receiving feed-grade betaine (quadratic effect, P < 0.1) than for control steers. Marbling scores were not affected by supplemental betaine, but the percentage of carcasses grading USDA Select was lower (linear and quadratic effects, P < 0.1) for steers fed feed-grade betaine than for control steers, predominantly due to a greater percentage grading USDA Choice. In Exp. 2, 312 heifers (343 kg initial BW) were used in a finishing study to evaluate the effects of graded levels of feed-grade betaine and peroxide-treated feather meal on performance and carcass characteristics. Treatments included two finishing diets (containing peroxide-treated or untreated feather meal) and four levels (0, 4, 8, and 12 g/d) of feed-grade betaine arranged in a 2 x 4 factorial. No significant interactions occurred between treatment of feather meal and betaine. Treatment of feather meal with hydrogen peroxide (5% wt/wt) increased in situ protein degradability but did not alter DMI, ADG, gain efficiencies, or carcass characteristics of heifers when it replaced untreated feather meal in the diet. Top-dressing feed-grade betaine to the diets had no effect on DMI, ADG, and gain efficiencies. Marbling scores were greater (cubic effect, P < 0.05) for heifers fed diets top-dressed with 4 and 12 g/d of feed-grade betaine, but other carcass characteristics were not altered significantly. Overall, feed-grade betaine and CSB did not alter growth performance, but did have minor effects on carcass characteristics.

Adipose Tissue↗
PubMed2004

Recovery of the rabbit's conditioned nictitating membrane response without direct reinforcement after extinction.

Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CSA--e.g., tone), the pairing of a novel, cross-modal stimulus (CSB--e.g., light) with the unconditioned stimulus (US) results in strong recovery of responding to the extinguished CSA. Experiment 1 demonstrated that the recovery of responding to CSA is not the result of US reinstatement but is attributable to pairings of CSB with the US. Experiment 2 demonstrated that the recovery of responding is specific to CSA and is not the result of cross-modal generalization. Experiment 3 revealed that a large number of CSB-US pairings in Stage 1 significantly reduced the amount of recovery to CSA during subsequent CSB-US trials. Experiment 3 also provided unexpected evidence of cross-modal secondary extinction. The extinction and subsequent recovery of responding seen in the present experiments is discussed with respect to possible contributions from contextual associations, CS processing, US processing, conditioned response expression, and layered excitatory associations.

Animals↗
PubMed2002

[Surgical treatment of progressive and symptomatic retinal detachment in senile retinoschisis].

BACKGROUND: This is 23-years retrospective study of consecutive, non-selected patients with senile retinoschisis and rare progressive and symptomatic retinal detachment (RD). The presence of RD was manifested by spectrum of retinal pathology of inner and outer layers of senile retinoschisis, ranging from simple holes to giant tears with or without proliferative vitreoretinopathy. The goals of this study were: 1--to evaluate the characteristics of the progressive and symptomatic RD based on detail preoperative examination of the eye, 2--to evaluate the anatomic and functional results of RD surgery. PATIENTS AND METHODS: From 1978 to 1999, RD surgery was performed on 57 eyes of 55 patients (28 men and 27 women) with senile retinoschisis and progressive and symptomatic RD. On average, we observed the patients for approximately 11.3 years after surgery; the minimum follow-up period was 20 months. The patients were divided in two groups according to the preoperative findings and the surgical procedures. Based on the size and the location of the defects of the inner and outer layer of senile retinoschisis and the proliferative vitreoretinopathy these procedures were indicated: 1--Uncomplicated cases of progressive and symptomatic retinal detachment were operated on primary cryopexy and scleral buckling (CSB) with episcleral silicone implants in 45 eyes. 2--Complicated cases of progressive and symptomatic retinal detachment underwent a pars plana vitrectomy (PPV) in 12 eyes: a--primary PPV was used as the primary treatment method in 6 eyes, b--secondary PPV as a secondary treatment method after unsuccessfully primary CSB with episcleral silicone implants in next 6 eyes. RESULTS: Characteristics preoperative findings were: RD in two or more quadrants in 84.2% of the eyes, including macula region in 71.9% of the eyes. Defect of the outer layer of senile retinoschisis was located postequatorial in 80% of the eyes, large retinal tears were found in 53.3% of the eyes and single defect was diagnosed in 68.8% of the eyes. Defect the of inner layer of senile retinoschisis was located equatorial in 69.5% of the eyes, small defects were found in 78.2% of the eyes and multiple defects were diagnosed in 58.6% of the eyes. Defects of the outer and the inner layer of senile retinoschisis were diagnosed in the equal quadrant in 61.4% of the eyes. The results of surgery varied, depending on the size and location of the defects of the inner and outer layer of senile retinoschisis and proliferative vitreoretinopathy: 1--The complete retinal reattachment in group treated with CSB was achieved in 43 eyes (95.5%), the average visual acuity was 0.34-2--The complete retinal reattachment in group treated with PPV was achieved by: a--primary PPV in six eyes, the average visual acuity was 0.37, b--secondary PPV four eyes, the average visual acuity was 0.16. CONCLUSIONS: Characteristic of senile retinoschisis, especially its defects of inner and outer layers is important preoperative finding for optimal indication of primary surgical treatment of progressive and symptomatic retinal detachment. According to our clinical experiences we created the syllabus of the care about the senile retinoschisis and syllabus of surgical treatment of progressive and symptomatic RD. Standard surgical procedures are the CSB and in the last period also primary PPV.

Adult↗
PubMed1991

[Inhibitory effects of alcoholic extract of Cordyceps sinensis on abdominal aortic thrombus formation in rabbits].

Aortic thrombosis in de-endotheliazed rabbit and 51Cr labeled autologous platelets were used for the evaluation of in vivo effects of CsB-851 on platelet-vessel wall interaction. The result showed that when CsB-851, an active part of alcoholic extract of mycelium from Cordyceps sinensis (Berk.) Sacc., was infused intravenously, the 51Cr labeled platelet number per gram dry weight of injured abdominal aorta (98.14 +/- 9.41 x 10(6)) was much lower than that in the control group (201.25 +/- 27.21 x 10(6)) in a concentration dependent manner. This indicated that CsB-851 could inhibit thrombus formation at the de-endotheliazed surface of the aorta. Since it could inhibit platelet aggregation in vitro had no effect on coagulation function in vivo, it seemed that the inhibitory effect of CsB-851 on arterial thrombus formation was mainly related to the inhibition of platelet functions.

Animals↗
PubMed1993

Real-time processing of serial stimuli in classical conditioning of the rabbit's nictitating membrane response.

Real-time models contend that a conditioned stimulus (CS) gives rise to a cascade of hypothetical stimuli that govern conditioned responses (CRs) on a moment-by-moment basis. Experiments with the rabbit nictitating membrane response successfully extended these models to external stimuli. CSs were trained in sequence with an unconditioned stimulus (CSA-CSB-US). When the CSA-CSB interval was shortened, the CR was compressed; when the CSA-CSB interval was lengthened, the CR was broadened. Peaks appeared at 2 places, namely, 1 following CSA by a period equal to its CS-US interval and another following CSB by its CS-US interval. Outside the sequence, the individual CSs evoked CRs located between their respective CS-US intervals. When, however, the 2 CSs were trained separately, the CRs were appropriate to their respective CS-US intervals when tested alone or in sequence. The results are discussed in terms of the J.E. Desmond and J.W. Moore (1988) and S. Grossberg and N.A. Schmajuk (1989) models.

Animals↗
PubMed1998

Surgical treatment of atherosclerotic lesions of subclavian artery: carotid-subclavian bypass versus subclavian-carotid transposition.

BACKGROUND: The aim of this retrospective study is to analyze the short and long term results of two different surgical treatments in patients with subclavian lesions: common carotid-subclavian artery bypass (CSB) versus transposition of subclavian artery on the common carotid artery (SCT). METHODS: From 1981 until 1995, 40 non randomized patients with symptomatic subclavian steal underwent 20 CSBs and 20 SCTs. Risk factor rates were equally balanced in the two groups. Surgery was carried out routinely under general anesthesia, with electroencephalic continuous monitoring. Patency of revascularization was assessed by physical examination, brachial blood pressure determinations, ultrasound sonography and angiography whenever recurrence of symptoms developed or when the function of repair was in doubt. Patients were examined every year. In Spring 1996 (range 9-189 mos, average 7 years) a general clinical-instrumental follow-up was performed. RESULTS: In the short term (<30 days) mortality was 5%: one death (5%) for pulmonary embolism in a patient with CSB and one for myocardial infarction in a patient with SCT. The early thrombosis rate was 5% (1 CSB and 1 common carotid artery distal to a patent SCT). During follow-up 10 patients (25%) died and 6 were lost. The six-year actuarial patency rate was 100% for SCT and 66% for CSB. Moreover there were 3 thromboses of the vertebral artery homolateral to patent CSBs. CONCLUSIONS: In conclusions SCT should be considered the surgical technical choice for the treatment of proximal subclavian artery lesions.

Adult↗
PubMed2006

The isoflavonoid aglycone-rich fractions of Chungkookjang, fermented unsalted soybeans, enhance insulin signaling and peroxisome proliferator-activated receptor-gamma activity in vitro.

We investigated anti-diabetic candidates and their mechanisms from the fractions of Chungkookjang (CKJ), a traditional fermented unsalted soybean, by investigating insulin signaling, peroxisome proliferator-activated receptor (PPAR)-gamma activity and glucose-stimulated insulin secretion, in vitro. Cooked soybeans (CSB) and CKJ, fermented predominantly with Bacillus subtilis, were extracted by 70% EtOH followed by an XAD-4 column chromatography with a serial mixture of solvents comprised of MeOH and water. During fermentation, the contents of isoflavonoid aglycones were elevated, and the fractions enriched with aglycones enhanced insulin-stimulated glucose uptake in 3T3-L1 adipocytes. This increase in glucose uptake resulted from stimulating a translocation of the glucose transporter (GLUT)-4 into the plasma membrane through the phosphorylation of insulin receptor substrate (IRS)-1 and Akt. Especially, daidzein enriched fractions elevated insulin-stimulated glucose uptake by acting as PPAR-gamma agonist up to levels exhibited when 10 nM insulin is administered. Fractions containing small peptides with low polarity in CKJ slightly increased glucose-stimulated insulin secretion. The data suggest that an increase in isoflavonoid aglycones in CKJ, in comparison to CSB, enhances glucose utilization via activating insulin signaling and stimulates PPAR-gamma activity in adipocytes. In addition, CKJ contains small peptides improving glucose-stimulated insulin secretion in insulinoma cells. Overall, CKJ is superior to CSB in anti-diabetic action.

3T3-L1 Cells↗
PubMed1999

Maintenance of CD34 expression during proliferation of CD34+ cord blood cells on glycosaminoglycan surfaces.

Recent studies have indicated that glycosaminoglycan (GAG) interactions with hematopoietic progenitors play a significant role in the regulation of hematopoiesis. However, the details of these interactions are not clear. In this study, we examined the role of soluble and immobilized GAGs in the proliferation of CD34+ cells. Chitosan, a cationic polysaccharide, was used to immobilize GAGs in ionic complex membranes. The GAGs studied were heparin, hyaluronate, and chondroitin sulfates A, B, and C. CD34-enriched umbilical cord blood cells were seeded onto tissue culture plates coated with the GAG-chitosan complex membranes. Cultures were maintained in medium supplemented with stem cell factor and interleukin 3 for up to six weeks, during which total and CD34+ cell numbers were determined by flow cytometry. Total cell number expansion ranged from 25-fold to 40-fold after six weeks. However, only heparin and chondroitin sulfate B (CSB) surfaces retained a significant CD34+ fraction. All other surfaces exhibited declines in CD34 expression, with negligible CD34+ percentages remaining after four weeks. In contrast, heparin and CSB surfaces exhibited CD34+ fractions as high as 90% after four weeks. GAG desorption studies indicated that the observed effects were partly mediated by desorbed GAGs in a concentration dependent manner. Subsequent studies showed that sustained high (160 microg/ml) heparin levels had toxic effects, while the same concentration of CSB exhibited more rapid early proliferation of CD34+ cells. In conclusion, this culture system has demonstrated the ability to produce simultaneous proliferation and CD34+ cell enrichment of a partially purified cord blood population by controlling the nature and levels of GAG moieties to which the cells are exposed. The results indicate that specific GAGs can significantly influence the growth and differentiation characteristics of cultured CD34+ cells.

Animals↗
PubMed1996

Cockayne syndrome complementation group B associated with xeroderma pigmentosum phenotype.

Two siblings have been reported whose clinical manifestations (cutaneous photosensitivity and central nervous system dysfunction) are strongly reminiscent of the DeSanctis-Cacchione syndrome (DCS) variant of xeroderma pigmentosum (XP), a severe form of XP. Fibroblasts from the siblings showed UV sensitivity, a failure of recovery of RNA synthesis (RRS) after UV-irradiation, and a normal level of unscheduled DNA synthesis (UDS), which were, unexpectedly, the biochemical characteristics usually associated with Cockayne syndrome (CS). However, no complementation group assignment in these cells has yet been performed. We here report that these patients can be assigned to CS complementation group B (CSB) by cell fusion complementation analysis. To our knowledge, these are the first patients with defects in the CSB gene to be associated with an XP phenotype. The results imply that the gene product from the CSB gene must interact with the gene products involved in excision repair and associated with XP.

Cell Fusion↗