[Polarized populations of T helper cells in patients with chronic hepatitis B virus infection]

OBJECTIVES

To investigate the composition of Th1/Th2/Th3 cells in chronic HBV-infected individuals by determining the expression of IL-4/IFN-gamma/TGF-beta in single CD4+ T cell isolated from the peripheral blood mononuclear cells (PBMCs), and analyze the role of Th cells polarized population in chronic HBV-infection.

METHODS

PBMCs from chronic HBV infected individuals were separated routinely, stimulated by PMA/Ionomycin/Monensin, and the production of IL-4/IFN-gamma/TGF-beta by CD4+ T cells in PBMCs was determined by FACS analysis.

RESULTS

The percentage of IFN-gamma-producing T cells, IL-4-producing T cells and TGF-beta producing T cells ranged from 2.3%-18.6%, 1.1%-8.7% and 0.7%-7.1%, respectively, in CD4+ cells from non-infected individuals. The majority of CD4+ T cells from PBMCs in chronic HBV-infected individuals were Th0 cells. The proportion of Th1 cells increased significantly with the hepatic inflammation activity, and the proportion in active period of chronic hepatitis B was higher than that in nonactive period (P < 0.05). The percentage of Th2 cells in CD4+ T cells from HBV-infected individuals did not differ significantly (P > 0.05), but it was higher than controls (P < 0.05). The percentage of Th3 cells in CD4+ T cells from AsC group was higher than that in CHB group and control (P < 0.05).

CONCLUSIONS

Th1 phenotype cytokine are correlated with hepatic inflammation activity of chronic hepatitis B. Th2 cells may be associated with the persistence of HBV infection. Th3 cells cooperating with Th2 cells exert negative immunoregulating action and may be associated with the immune tolerance state of chronic HBV infection.

Dietary plasma protein is used more efficiently than extruded soy protein for lean tissue growth in early-weaned pigs

We compared the effects of supplementing either animal plasma or extruded soy protein in the diet based on the efficiency of dietary protein utilization for lean tissue growth in early-weaned pigs. Twenty-four 14-d-old pigs (4 kg body weight) were pair-fed (per kg body weight) either a control diet containing extruded soy protein (C; n = 12) or a diet with 10% animal plasma (P; n = 12) for 24 d. During the 24 days, protein intake was not different, yet mean daily body weight gains (+23%) and food conversion efficiencies (expressed as the ratio of body weight gain to protein intake) (+19%) were greater (P < 0.05) in the P group than in the C group. Lean body mass measured after 24 d, using both dual-energy X-ray absorptiometry and total body potassium analysis, was significantly (P < 0.05) greater (approximately 16%) in P than in C pigs. The circulating urea concentrations were 40% lower (P < 0.05) in P than in C pigs. Our results demonstrate that supplementing early-weaned pig diets with animal plasma rather than extruded soy protein increased the efficiency of dietary protein use for lean tissue growth and that this response is mediated in part by decreased amino acid catabolism.

[The impact of hepatitis B virus infected patients or donors on the outcome of hematopoietic stem cell transplantation]

OBJECTIVE

To investigate the impact of recipients and/or donors infected with hepatitis B on the outcome of hematopoietic stem cells transplantation (HSCT).

METHODS

We analyzed retrospectively the transplantation outcome in 26 of 164 hematological diseases patients who and whose donors were infected with hepatitis prior to transplantation.

RESULTS

(1) Three of the 26 patients developed VOD after HSCT, the incidence (11.5%) is significant higher than that in patients and donors who did not infected with HBV (P < 0.05). (2) Two of 5 patients transfused hematopoietic stem cells from HBsAg + donors developed hepatitis B. (3) Four patients with allogeneic stem cell transplantation developed hepatic failure (HF) which occurred during cyclosporin (CsA) being tapered off or withdrawal. The incidence of HF in patients and/or donors infected with HBV (15.4%) is obviously higher than that in patients and donors who did not (0.08%, P < 0.01). (4) In 4 patients with HbeAg +, 2 patients died of HF after allogeneic HSCT, the other 2 patients survived after autologous HSCT.

CONCLUSION

Donors and recipients infected with hepatitis B are not contraindication of HSCT, but patients with allogeneic HSCT are in danger to develop LF during CsA being tapered off or withdrawal.

[The degradation performance of bioabsorbable acylchitin fiber reinforced PLA composite materials in vitro and in vivo]

The present authors have investigated the degradation performance of acylchitin fiber reinforced polylactide composite materials plates both in vitro and in vivo. The initial flexural strength and the initial flexural modulus of this plate are 114.72 MPa and 3980.05 MPa, respectively. The flexural strength of this plate decreases to 31.42 MPa after the plate has been submerged in injectio natrii lactatic ringeri tissue fluid for a period of 16 weeks at 37 degrees C. Both the in vitro degradation performance and the strength retention of this plate are better than those of the self-reinforced PGA/PLA and PGA, though the initial strength of the latter two being much higher than that of the former. The degradation products of the chitin/PLA composite materials can be absorbed by metabolic pathway.

Minimal enteral nutrient requirements for intestinal growth in neonatal piglets: how much is enough?

BACKGROUND

Parenterally nourished preterm infants commonly receive minimal enteral feedings, the aim being to enhance intestinal function. Whether this regimen increases intestinal growth has not been established.

OBJECTIVE

Our objective was to determine the minimal enteral nutrient intakes necessary to stimulate and to normalize neonatal intestinal growth.

METHODS

Intestinal growth and cell proliferation were quantified in neonatal pigs given equal amounts of an elemental nutrient solution for 7 d. Different groups (n = 5-7 per group) received 0%, 10%, 20%, 40%, 60%, 80%, or 100% of total nutrient intake enterally, with the remainder given parenterally.

RESULTS

In the jejunum, wet weight, protein mass, and villus height were significantly greater at enteral intakes >40%. Stimulation of ileal protein mass required a higher enteral intake (60%). In both segments, abrupt increases in DNA mass, crypt depth, ornithine decarboxylase activity, and crypt cells in S-phase occurred between enteral intakes of 40% and 60%. Circulating concentrations of glucagon-like peptide-2 and peptide YY, but not gastrin, increased significantly between enteral intakes of 40% and 60% and closely paralleled indexes of cell proliferation.

CONCLUSIONS

The minimal enteral nutrient intake necessary to increase mucosal mass was 40% of total nutrient intake, whereas 60% enteral nutrition was necessary to sustain normal mucosal proliferation and growth. Our results imply that providing <40% of the total nutrient intake enterally does not have significant intestinal trophic effects.

Hsc70 chaperones clathrin and primes it to interact with vesicle membranes

When Hsc70 uncoats clathrin-coated vesicles in an auxilin- and ATP-dependent reaction, a single round of rapid uncoating occurs followed by very slow steady-state uncoating. We now show that this biphasic time course occurs because Hsc70 sequentially forms two types of complex with the dissociated clathrin triskelions. The first round of clathrin uncoating is driven by formation of a pre-steady-state assembly protein (AP)-clathrin-Hsc70-ADP complex. Then, following exchange of ADP with ATP, a steady-state AP-clathrin-Hsc70-ATP complex forms that ties up Hsc70, preventing further uncoating. This steady-state complex forms only during uncoating in the presence of APs; in the absence of APs, Hsc70 rapidly dissociates from the uncoated clathrin and continues to carry out uncoating. Whether it is complexed with ATP or ADP, the steady-state complex has very different properties from the pre-steady-state complex in that it cannot be immunoprecipitated by anti-clathrin antibodies and is readily dissociated by fast protein liquid chromatography. Remarkably, when the steady-state complex is incubated with uncoated vesicle membranes in ATP, the pre-steady-state complex reforms, suggesting that the clathrin triskelions in the steady-state complex rebind to the membranes and are again uncoated by Hsc70. We propose that Hsc70 not only uncoats clathrin but also chaperones it to prevent it from inappropriately polymerizing in the cell cytosol and primes it to reform clathrin-coated pits.

[Treatment of acute lymphoblastic leukemia by autologous stem cell transplantation: an analysis of 30 cases]

OBJECTIVE

To evaluate the clinical outcome of autologous stem cell transplantation (ASCT) in acute lymphoblastic leukemia (ALL) and the affected factors.

METHODS

Data of 30 ALL patients received ASCT in our hospital between July 1987 and December 1997 were retrospectively analyzed. Twenty-four of them were in the first complete remission (CR(1)) and six in the second complete remission (CR(2)) or early relapse (ER). Conditioning regimens were CTX 120 mg/kg + single total body irradiation 9 - 10 Gy (sTBI) or Bu 16 mg/kg of Mel 140 - 180 mg/m(2) + Ara-c 2 - 4 g/m(2).

RESULTS

All patients reconstituted hematopoiesis. The median follow-up duration was 504 (18-3043) days. Transplant-related mortality was 10%. The probabilities of 3 year disease-free survival (DFS) for ALL in CR(1) and CR(2) were 67.7% +/- 10.3% and 16.7% +/- 15.2%, respectively (P = 0.00547); the 3 year DFS was significantly better with posttransplant treatment than without it (92.3% +/- 7.4% vs 50.0% +/- 17.7%, P = 0.0130).

CONCLUSION

Acute lymphoblastic leukemia patients without HLA-matched related donor are recommended for ASCT in CR(1). To reduce relapse and improve the outcome, adoptive immunotherapy or maintenance chemotherapy should be given after ASCT.

Dietary plasma protein reduces small intestinal growth and lamina propria cell density in early weaned pigs

ABSTRACT We quantified the effects of a diet containing animal plasma protein on small intestinal growth and mucosal morphology in early weaned pigs. Ninety-six pigs [14 d old, 4 kg body weight (BW)] were assigned in groups of 32 to three dietary treatments as follows: 1) free access to control diet (C), 2) free access to plasma protein diet (P), and 3) plasma protein, pair-fed to C (PPF). Eight pigs from each group were killed at 2, 4, 8 or 16 d. Over a 16-d period, weight gain in the P group was 43% greater (P < 0.05) than that in C pigs; weight gain was similar in C and PPF groups. Protein intake in the P group was 33% higher (P < 0.05) than that in the PPF group; no significant difference was observed between the C and P groups. Dietary protein conversion efficiencies in both the P and PPF groups were approximately 18% greater (P < 0.05) than those in the C group. Intestinal masses in the three groups did not differ at 2, 4 and 8 d. By 16 d, the jejunal and ileal protein and DNA masses (mg/kg BW) in both the P and PPF groups were lower than those in the C group (P < 0.05). Dietary plasma protein did not affect crypt cell proliferation, crypt depth or villous height in either the jejunum or ileum. However, the intravillous lamina propria cell density in the jejunum was significantly lower (P < 0.05) in P and PPF pigs than in C pigs. Plasma urea concentrations were also 40 and 42% lower (P < 0.05) in the P and PPF groups, respectively, than in the C group. Our results indicate that dietary plasma protein reduces the cellularity of the lamina propria, but not epithelial cell surface of the small intestine. Feeding plasma protein also increased the efficiency of dietary protein utilization, in part, by decreasing amino acid catabolism.

A multiple-capillary electrophoresis system for small-scale DNA sequencing and analysis

A five-capillary system has been developed for DNA sequencing and analysis. The post-column fluorescence detector is based on a sheath-flow cuvette. The instrument provides uniform and continuous illumination of the samples. The cuvette virtually eliminates cross-talk in the fluorescence signal between capillaries. Discrete single-photon counting avalanche photodiodes provide high efficiency light detection. The instrument has detection limits (3sigma) of 130 +/- 30 fluorescein molecules injected onto each capillary. Over 650 bases of sequence at 98.8% accuracy were generated in 100 min at 50 degrees C from M13mp18. Separation and detection of short tandem repeats proved efficient and accurate with the use of internal standards for direct comparison of migration times between capillaries.

[Study on the posterior vitreous detachment in patients with high myopia]

OBJECTIVE

To access the development of posterior vitreous detachment(PVD) related to age, axial length of the eye, vitreous changes as well as the myopic chorioretinal manifestation in patients with high myopia.

METHODS

The vitreous status of 61 consecutive patients with high myopia(> or = -8.0 D and axial length > or = 26.0 mm) 110 eyes and 68 controls (< or = -3.0 D) 119 eyes were examined with biomicroscopic slit lamp and B-scan ultrasound. The myopic chorioretinal changes at the posterior pole were examined by indirect ophthalmoscope. The axial length of the eye was measured by A-scan ultrasound. The incidence of PVD was evaluated by Chi-square test.

RESULTS

The incidence of PVD in patients with high myopia increased with age. Its overall incidence was significantly higher than that in the controls (78.2% vs 31.1%, P < 0.001). In addition, the onset of PVD in patients with high myopia occurred much earlier in age than that in the control group. Axial length was an important factor responsible for the development of PVD in patients with high myopia. The incidence of PVD and age were highly correlated (r = 0.9997, P < 0.05). Retinal detachment occurred in 5 eyes in the patients with high myopia.

CONCLUSIONS

The results in the present study suggested that the incidence of PVD in patients with high myopia, increased with axial length of the eye and age. Vitreous changes are characteristic findings associated with high myopia, which was also involved in the development of PVD.

Absorption of sunscreens across human skin: an evaluation of commercial products for children and adults

AIMS

Topical sunscreens are routinely applied to the skin by a large percentage of the population. This study assessed the extent of absorption of a number of common chemical sunscreen agents into and through human skin following application of commercially available products.

METHODS

Sunscreen products were applied to excised human epidermis in Franz diffusion cells with the amount penetrating into and across the epidermis assessed by h.p.l.c. for 8 h following application.

RESULTS

All sunscreen agents investigated penetrated into the skin (0.25 g m-2 or 14% of applied dose), but only benzophenone-3 passed through the skin in significant amounts (0.08 g m-2 or 10% of the applied dose). With one exception, suncreen agents in corresponding products marketed for adults and children had similar skin penetration profiles.

CONCLUSIONS

Whilst limited absorption across the skin was observed for the majority of the sunscreens tested, benzophenone-3 demonstrated sufficiently high penetration to warrant further investigation of its continued application.

[Antagonistic effects of metallothionein on genetic damage caused by gamma-rays and mitomycin C]

OBJECTIVE

To study the antagonistic effects of metallothionein (Zn-MT)on genetic damage caused by gamma-rays and mitomycin C (MMC) in the liver of rabbits.

METHODS

Micronucleus test and DNA strand breaks were determined in vitro and in vivo with single-cell gel electrophoresis assay to observe the effects of Zn-MT on the micronucleus formation and cleavage of DNA chain before and after gamma-rays radiation and MMC treatment.

RESULTS

A dose of 664 microg/kg of Zn-MT could inhibit micronucleus formation in the bone marrow of the mice induced by 5 Gy gamma-rays radiation (P < 0.05). Concentrations of 10 and 50 microg/ml Zn-MT could antagonize the increase in bimicronucleus frequency in g12 cells induced by 1 and 3 Gy gamma-rays radiation and 0.3 microg/ml MMC treatment (P < 0.05 or P < 0.01). A dose of 50 microg/ml Zn-MT could reduce the DNA single strand breaks caused by 1 Gy gamma-rays radiation, but without statistical significance (P > 0.05).

CONCLUSION

Zn-MT could antagonize the genetic damage to certain extent in the liver of the rabbits caused by gamma-rays radiation and MMC treatment.

[Surgical management of acute retinal necrosis]

OBJECTIVE

To investigate the effects of vitreoretinal surgery in the management of acute retinal necrosis (ARN).

METHODS

17 cases (20 eyes) of ARN had undertaken the surgery, including vitreoretinal surgery for 18 eyes and scleral surgery for 2 eyes. 14 cases (21 eyes) of ARN patients hospitalized at the same period without surgery were used as controls.

RESULTS

The follow-up was 5 months to 5 years. 15 eyes in the control group (71.4%) became phthisis bulbi. Useful vision remained in 17 eyes in the surgical group.

CONCLUSIONS

Retinal detachment is still a severe complication of ARN, and proper vitreoretinal surgery can improve its prognosis.

Human B cells accumulate immunoglobulin V gene somatic mutations in a cell contact-dependent manner in cultures supported by activated T cells but not in cultures supported by CD40 ligand

The acquisition of somatic mutations in the rearranged immunoglobulin V regions in B cells occurs within the tightly regulated microenvironment of a germinal centre. The precise mechanism responsible for turning on the mutational process is unknown. To dissect the role of different components of the germinal centre in this mechanism, we have used in vitro cultures of normal human IgD+ peripheral blood B lymphocytes co-cultured with activated CD4+ T cells, or with resting CD4+ T cells, or with CD40 ligand and IL-4. We observed that if the cultures included activated CD4+ T cells, then up to 100% of VH transcripts on day 14 were somatically mutated. Transcripts were found to carry from one to 36 substitutions (median five). In contrast, in the absence of activated T cells, transcripts contained only background levels of somatic mutation irrespective of the presence of resting T cells or CD40 ligand and IL-4. Cell-cell contact was required for mutation because mutations were not detected when B cells were separated from activated T cells by a membrane.

[Secretory expression of salmon calcitonin in Streptomyces lividans]

A gene coding for salmon calcitonin precursor (sCT-Gly) was amplified from salmon genomic DNA by Polymerase Chain Reaction (PCR) and fused to the expression and secretion signals of melC1 amplified by PCR. The fusion gene was cloned into the Streptomyces vector pIJ680 and expressed under the control of aminoglycoside phosphotransferase gene (aph) promoter. Streptomyces lividans TK54 transformed with the expression plasmid (pMS680) secreted biologically active sCT-Gly into the culture medium which was confirmed by Enzyme Immunoassay (EIA) and bioassay. Production of sCT-Gly by the recombinant strain in YEME medium reached a maximum of 100 micrograms/L culture at about 96 h. The recombinant sCT-Gly had almost the same HPLC retention time as the standard sCT obtained from Sigma.

Notch signalling pathway mediates hair cell development in mammalian cochlea

The mammalian cochlea contains an invariant mosaic of sensory hair cells and non-sensory supporting cells reminiscent of invertebrate structures such as the compound eye in Drosophila melanogaster. The sensory epithelium in the mammalian cochlea (the organ of Corti) contains four rows of mechanosensory hair cells: a single row of inner hair cells and three rows of outer hair cells. Each hair cell is separated from the next by an interceding supporting cell, forming an invariant and alternating mosaic that extends the length of the cochlear duct. Previous results suggest that determination of cell fates in the cochlear mosaic occurs via inhibitory interactions between adjacent progenitor cells (lateral inhibition). Cells populating the cochlear epithelium appear to constitute a developmental equivalence group in which developing hair cells suppress differentiation in their immediate neighbours through lateral inhibition. These interactions may be mediated through the Notch signalling pathway, a molecular mechanism that is involved in the determination of a variety of cell fates. Here we show that genes encoding the receptor protein Notch1 and its ligand, Jagged 2, are expressed in alternating cell types in the developing sensory epithelium. In addition, genetic deletion of Jag2 results in a significant increase in sensory hair cells, presumably as a result of a decrease in Notch activation. These results provide direct evidence for Notch-mediated lateral inhibition in a mammalian system and support a role for Notch in the development of the cochlear mosaic.

In vitro human epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 from a range of solvents

PURPOSE

To study epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 (BP) from a range of single solvent vehicles and evaluate solvent effects on permeability parameters.

METHODS

The solubility of BP was measured in a number of solvents. Penetration of BP across human epidermis and high density polyethylene (HDPE) membranes was studied from 50% saturated solutions in each solvent.

RESULTS

Maximal BP fluxes from the solvents across the two membranes varied widely. Highest fluxes were observed from 90% ethanol (EtOH) for epidermis and from isopropyl myristate (IPM) and C12-15 benzoate alcohols (C12-15 BA) for HDPE membrane. Both the flux and estimated permeability coefficient and skin-vehicle partitioning of BP appeared to be related to the vehicle solubility parameter (delta(v)). The major effects of solvents on BP flux appear to be via changes in BP diffusivity through the membranes.

CONCLUSIONS

Minimal penetration of sunscreens such as BP is best achieved by choosing vehicles with a delta(v) substantially different to the solubility parameter of the membrane.

Genomic organization, expression and chromosomal localization of the mouse Slug (Slugh) gene

The Slug gene encodes a zinc finger protein implicated in the generation and migration of neural crest cells in several vertebrate species. Here we describe the genomic organization and chromosomal localization of the mouse Slug (Slugh) gene. The mouse Slug gene consists of three exons spanning approx. 4 kb. Northern blot analysis of RNA isolated from several tissues of adult mice revealed the presence of a single 2.1 kb transcript. The chromosomal location of mouse Slug was determined by interspecific backcross analysis. The mapping results indicated that Slugh is located in the proximal region of mouse chromosome 16.

Conjugates of Tremella polysaccharides with microbeads and their TNF-stimulating activity

A mannan (A) and a heteroglycan (D) were prepared by partial acidic hydrolysis of T3, a major polysaccharide fraction of the fungus Tremella fuciformis Berk. Methylation analysis of A and D showed that they contained a 1-->3 linked mannosyl main chain, to which were linked different side chains at position 2, 4, or 6 of the mannosyl residues. A and D were conjugated to albumin microbeads (AM) by reductive amination. The conjugates showed significant cytokine-stimulating activity in vitro whereas unconjugated AM had no activity. Not conjugated A and D showed cytokine-stimulating activity only in about 100 times higher concentrations.

The Slug gene is not essential for mesoderm or neural crest development in mice

The Slug gene encodes a zinc finger protein, homologous to the product of the Drosophila Snail gene, that is implicated in the generation and migration of both mesoderm and neural crest cells in several vertebrate species. We describe here the cloning and genetic analysis of the mouse Slug (Slugh) gene. Slugh encodes a 269-amino-acid protein the shares 92% amino acid identity with the product of the chicken Slug gene. We have characterized Slugh gene expression during early mouse embryogenesis by whole mount in situ hybridization of Slugh mRNA and through detection of beta-galactosidase expression from an in-frame SlughIacZ allele generated through homologous recombination. Slugh expression is first detected in extraembryonic mesoderm and is later detected in many mesodermal subsets, although it is not detected in the primitive streak. In contrast to many other vertebrates, the mouse Slug gene is not expressed in premigratory neural crest cells but is expressed in migratory neural crest cells. Analysis of a targeted null mutation that deleted all Slugh coding sequences revealed that Slugh is not required for mesoderm formation or for neural crest generation, migration, or development in mice. These results indicate that neither the expression pattern nor the biological function of the Slug gene is conserved among all vertebrates. These data also raise interesting questions about the regulation of neural crest generation, which is one of the distinguishing characteristics of the vertebrate subphylum.

VH usage and somatic hypermutation in peripheral blood B cells of patients with rheumatoid arthritis (RA)

The human antibody repertoire has been demonstrated to have a marked V-gene-dependent bias that is conserved between individuals. In RA patients, certain heavy chain V genes (VH) have been found to be preferentially used for encoding autoantibodies. To determine if such preferential use of VH genes in autoantibodies is associated with a general distortion of the V gene repertoire in RA patients, the VH composition of peripheral blood B cells was analysed among four RA patients and four age- and sex-matched healthy controls. Usage of individual VH genes (eight VH3 and three VH4 genes tested by hybridization with a set of gene-specific oligonucleotide probes) was highly biased among RA patients, but no evidence of a distortion in the bias was observed compared with healthy controls. However, the occurrence of somatic mutations in these VH genes (estimated by differential hybridization with motif-specific oligonucleotide probes targeted to CDR and FR of the tested genes, and by DNA sequence analysis) was strikingly different between patients and healthy subjects. The number of VH3 rearrangements that had accumulated somatic mutations and the number of mutations per rearrangement were significantly elevated in three of the four RA patients. A slight but not significant elevation in mutations among rearranged VH4 genes was also observed in these patients. These data suggest that although usage of individual VH genes among peripheral blood B cells is not affected by the disease, the autoimmune process may involve a significant fraction of the B cell compartment.

[Treatment of acute optic neuritis with high dose of prednisone]

OBJECTIVE

The benefit of glucocorticoid for the treatment of acute optic neuritis remains controversial. The efficacy of oral prednisone in 12 patients (14 eyes) with acute optic neuritis was reviewed.

METHODS

The time of visual symptoms before treatment was 3-15 days. The visual acuities were worse than 0.1 in all patients, with positive relative afferent pupillary defect. Visual field defect and delay latency of P100 in pattern VEP were also found. The regimen of glucocorticoid therapy was oral prednisone, starting with 160 mg daily followed by reducing the dosage by 20 mg every three days until 40 mg per day was attained and then tapering the dosage at 70 mg every other day until stoppage of the drug. The treatment was 3-11 months and 9 patients were followed up more than one year.

RESULTS

The visual acuities improved rapidly and stable. After 4 days, the visual acuity was 0.2 or better in 10 eyes. It was better than 0.6 in 12 eyes at 15 days. At 6 months, all had the visual acuity better than 0.7, with 85.7% equal or better than 1.0.

CONCLUSIONS

The regimen of oral prednisone beginning with 160 mg followed by tapering for three months would be feasible. Pattern VEP was a sensitive and credible sign for evaluating the extent of demyelination.

[Application of IHW2 purged bone marrow to autologous bone marrow transplantation in the treatment of acute myeloid leukemia]

OBJECTIVE

To observe the clinical effectiveness of IHW2 purged autologous bone marrow transplantation (ABMT) in the treatment of AML patients.

METHODS

Large volume of bone marrow was purged in vitro by IHW2 and then reinfused to patients for ABMT.

RESULTS

All of the three patients transplanted with IHW2 purged autologous bone marrow successfully reconstituted hemopoiesis. Two patients got continuous complete remission for 36+ and 34+ months, respectively. The karyotype of one of the two patient was 46,XY,del(16)(q22) before ABMT and changed to 46,XY in 2 months after transplantation. The third patient relapsed after ABMT 19 months.

CONCLUSION

The preliminary study suggests that IHW2 may have certain purging effect on leukemic cells and is safe for clinical application.

Glucose-regulated interaction of a regulatory subunit of protein phosphatase 1 with the Snf1 protein kinase in Saccharomyces cerevisiae

The Snf1 protein kinase family has been conserved in eukaryotes. In the yeast Saccharomyces cerevisiae, Snf1 is essential for transcription of glucose-repressed genes in response to glucose starvation. The direct interaction between Snf1 and its activating subunit, Snf4, within the kinase complex is regulated by the glucose signal. Glucose inhibition of the Snf1-Snf4 interaction depends on protein phosphatase 1 and its targeting subunit, Reg1. Here we show that Reg1 interacts with the Snf1 catalytic domain in the two-hybrid system. This interaction increases in response to glucose limitation and requires the conserved threonine in the activation loop of the kinase, a putative phosphorylation site. The inhibitory effect of Reg1 appears to require the Snf1 regulatory domain because a reg1Delta mutation no longer relieves glucose repression of transcription when Snf1 function is provided by the isolated catalytic domain. Finally, we show that abolishing the Snf1 catalytic activity by mutation of the ATP-binding site causes elevated, constitutive interaction with Reg1, indicating that Snf1 negatively regulates its own interaction with Reg1. We propose a model in which protein phosphatase 1, targeted by Reg1, facilitates the conformational change of the kinase complex from its active state to the autoinhibited state.

Defects in limb, craniofacial, and thymic development in Jagged2 mutant mice

The Notch signaling pathway is a conserved intercellular signaling mechanism that is essential for proper embryonic development in numerous metazoan organisms. We have examined the in vivo role of the Jagged2 (Jag2) gene, which encodes a ligand for the Notch family of transmembrane receptors, by making a targeted mutation that removes a domain of the Jagged2 protein required for receptor interaction. Mice homozygous for this deletion die perinatally because of defects in craniofacial morphogenesis. The mutant homozygotes exhibit cleft palate and fusion of the tongue with the palatal shelves. The mutant mice also exhibit syndactyly (digit fusions) of the fore- and hindlimbs. The apical ectodermal ridge (AER) of the limb buds of the mutant homozygotes is hyperplastic, and we observe an expanded domain of Fgf8 expression in the AER. In the foot plates of the mutant homozygotes, both Bmp2 and Bmp7 expression and apoptotic interdigital cell death are reduced. Mutant homozygotes also display defects in thymic development, exhibiting altered thymic morphology and impaired differentiation of gamma delta lineage T cells. These results demonstrate that Notch signaling mediated by Jag2 plays an essential role during limb, craniofacial, and thymic development in mice.

Plasma cholecystokinin-8 in pigs with divergent genetic potential for feed intake and growth

Plasma cholecystokinin-8 (CCK-8) was studied in pigs with divergent genetic potential for feed intake. Differences in feed intake resulted from selection for either fast (line F) or slow (line S) postweaning gain. The hypothesis was that the relatively lesser feed intake in S versus F may be attributable, in part, to greater circulating concentrations of the putative satiety hormone CCK-8. In Experiment I, barrows from F (n = 23) and S (n = 19) were used to determine changes in CCK-8 associated with ad libitum feed consumption. Blood samples were collected after overnight feed deprivation, then periodically during a 2-hr feeding period. Averaged across sampling times, concentration of CCK-8 tended to be greater (P = 0.07) in S (6.70 pmol/l) than in F (5.06 pmol/l). Concentration of CCK-8 per unit of feed consumed (CCK-8/cumulative feed intake) was greater (P < 0.01) in S than in F during the first 30 min of the feeding period. In Experiment 2, plasma concentrations were determined for nine pairs (F, S) of the same barrows allowed an amount of feed equal to the previous ad libitum intake of the S barrow in the pair. Averaged across times, the difference between CCK-8 concentrations of S (11.65 pmol/l) and F (7.94 pmol/l) barrows was not significant (P = 0.18). A greater concentration of CCK-8 per unit of feed consumed in S than in F supports the hypothesis that satiety effects of CCK-8 may play a role in genetic differences between the lines for feed intake.

Characterization and cytokine-stimulating activities of acidic heteroglycans from Tremella fuciformis

Four acidic heteroglycans, T2a-T2d, were isolated from the body of Tremella fuciformis Berk. They contained 1.9%-2.9% of acetyl groups and were composed of mannose (Man), glucuronic acid (GlcA), and small amounts of xylose (Xyl), glucose (Glc), and fucose (Fuc). According to methylation analysis they had a mannan backbone consisting of 3-linked Man, and side chains containing glucosyl, mannosyl, fucosyl, xylosyl, and glucuronic acid residues. The side chains were attached through O-2, O-4, or O-6 in about 40 percent of backbone mannosyl residues. Molecular masses of the four polysaccharides were 410, 250, 34, and 20 kDa, respectively. T2a-T2d induced human monocytes to produce interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF) in vitro. The products of Smith degradation (T2a-S) and lithium degradation (T2a-L) of T2a and the product of deacetylation (T2b-D) of T2b also induced monocytes to secret IL-1 as efficiently as the original polysaccharides, indicating that xylosyl and glucuronic acid residues as well as acetyl groups were not important to promote the cytokine-stimulating activity.

Percutaneous absorption of sunscreen agents from liquid paraffin: self-association of octyl salicylate and effects on skin flux

This study provides an investigation of the availability of octyl salicylate (OS), a common sunscreen agent, from liquid paraffin and the effect of OS on skin permeability. A model membrane system to isolate the vehicle effect from membrane permeability has been developed. Partitioning of OS between liquid paraffin and aqueous receptor phases was conducted. Partition coefficients increased with increase in OS concentration. A range of OS concentrations in liquid paraffin was diffused across human epidermis and synthetic membranes into 4% bovine serum albumin in phosphate-buffered saline and 50% ethanol. Absorption profiles of OS obtained from silicone and low-density polyethylene (LDPE) membranes were similar to each other but higher than for the high-density polyethylene [HDPE (3 times)] membrane and human epidermis (15 times). The steady state fluxes and apparent permeability coefficients (Kp') obtained from the diffusion studies showed the same trends with all membranes, except for the HDPE membrane which showed greater increase in flux and Kp' at concentrations above 30%. IR spectra showed that several bands of OS were shifted with concentrations, and the molecular models further suggested that the main contribution to the self-association is from non-1,4 van der Waals interactions.

Gene targeting: things go better with Cre

New technologies are changing the way in which gene targeting experiments are being designed. It is now becoming possible to analyze gene function in defined tissues at specific times during the life of a mouse.

The Snf1 protein kinase and its activating subunit, Snf4, interact with distinct domains of the Sip1/Sip2/Gal83 component in the kinase complex

The Snf1 protein kinase plays a central role in the response to glucose starvation in the yeast Saccharomyces cerevisiae. Previously, we showed that two-hybrid interaction between Snf1 and its activating subunit, Snf4, is inhibited by high levels of glucose. These findings, together with biochemical evidence that Snf1 and Snf4 remain associated in cells grown in glucose, suggested that another protein (or proteins) anchors Snf1 and Snf4 into a complex. Here, we examine the possibility that a family of proteins, comprising Sip1, Sip2, and Gal83, serves this purpose. We first show that the fraction of cellular Snf4 protein that is complexed with Snf1 is reduced in a sip1delta sip2delta gal83delta triple mutant. We then present evidence that Sip1, Sip2, and Gal83 each interact independently with both Snf1 and Snf4 via distinct domains. A conserved internal region binds to the Snf1 regulatory domain, and the conserved C-terminal ASC domain binds to Snf4. Interactions were mapped by using the two-hybrid system and were confirmed by in vitro binding studies. These findings indicate that the Sip1/Sip2/Gal83 family anchors Snf1 and Snf4 into a complex. Finally, the interaction of the yeast Sip2 protein with a plant Snf1 homolog suggests that this function is conserved in plants.

[Hemorheological disorders in patients with sudden deafness]

Fourteen hemorheological and related parameters of blood samples derived from 59 patients with sudden deafness were observed and were compared with those of blood samples got from 512 healthy persons. The ratio viscosity of whole blood (6.50 +/- 1.07), reduced viscosity of whole blood (12.37 +/- 1.80), and plasma viscosity (1.84 +/- 0.14) in male patients were significantly higher than those (6.05 +/- 0.63, 11.06 +/- 1.04, and 1.70 +/- 0.07, respectively) in male controls. The reduced viscosity of whole blood (16.62 +/- 3.87) and plasma viscosity (1.92 +/- 0.13) in female patients were also significantly higher than those (14.40 +/- 2.27 and 1.72 +/- 0.06, respectively) in female controls. The findings above suggest that there is an intimate relationship between the microcirculationary disorder resulting from hemorheological changes and the onset of sudden deafness. The parameters related to plasma viscosity revealed that there were higher concentrations of plasma fibrinogen and triglyceride in male patients than those in male controls, while the concentrations of plasma cholesterol and triglyceride were higher in female patients than in female controls. These results indicate that the factors which induce the change of plasma viscosity in male patients could not be the same as those in female patients. Thus, in the process of treating sudden deafness, besides the use of common devices such as reducing blood viscosity and improving microcirculation, some other special steps based on the hemorheological parameters derived from different sexes or individuals, should also be considered.

Glucose regulates protein interactions within the yeast SNF1 protein kinase complex

The SNF1 protein kinase is broadly conserved in eukaryotes and has been implicated in responses to environmental and nutritional stress. In yeast, the SNF1 kinase has a central role in the response to glucose starvation. SNF1 is associated with its activating subunit, SNF4, and other proteins in complexes. Using the two-hybrid system, we show that interaction between SNF1 and SNF4 is strongly regulated by the glucose signal. Moreover, this interaction is appropriately affected by mutations in regulators, including protein phosphatase 1. We show that SNF4 binds to the SNF1 regulatory domain in low glucose, whereas in high glucose the regulatory domain binds to the kinase domain of SNF1 itself. Genetic analysis further suggests that the SNF1 regulatory domain autoinhibits the kinase activity and that in low glucose SNF4 antagonizes this inhibition. Finally, these interactions have been conserved from yeast to plants, indicating that homologs of the SNF1 kinase complex respond to regulatory signals by analogous mechanisms.

Characterisation of acidic heteroglycans from Tremella fuciformis Berk with cytokine stimulating activity

Four kinds of acidic heteroglycan, T3a-T3d, were isolated from the body of the fungus Tremella fuciformis Berk. The molecular weights of T3a-T3d were 550, 420, 55, and 48 kDa, respectively. Glycosidic linkage analysis showed that they had a mannan backbone consisting of 3-linked Man p, and side chains containing glucosyl, mannosyl, fucosyl, xylosyl, and glucuronic acid residues attached through O-2, O-4, or O-6 of about half of the backbone mannosyl residues. A partial acidic hydrolysate of T3a could be divided into a low-branching region (T3a-1, 2, 3, 4) mainly branched at the 2-position of 3-linked Man p in the mannan backbone, and a high-branching region (T3a-5A) branched at the 2,4- or 2,4,6-positions of 3-linked Man p in the backbone. The low-branching region, which is predominant in the backbone, was substituted with non-reducing terminal Glc pA, Fuc p and short side chains consisting of (1-->6)-linked Glc p and (1-->2)-linked Man p linked through C-2 of the mannan backbone. The high-branching region, which is a minor component of the backbone, was linked with long side chains of (1-->6)-linked Glc p and (1-->4)-linked Glc pA in their branching points. T3a-T3d were able to induce human monocytes to produce interleukin-1, interleukin-6, and tumor necrosis factor in vitro. The different fragments of the acidic hydrolysate of T3a (T3a-1, 2, 3, 4, 5A) also induced monocytes to secret interleukin-6 with high potency, indicating that the activity may be caused by a common structure, (1-->3)-mannan in the four heteroglycans and their fragments. The change of molecular weight had no obvious influence on the activity of the heteroglycans.

Supplementation with L-2-oxothiazolidine-4-carboxylic acid, a cysteine precursor, does not protect against lipid peroxidation in puromycin aminonucleoside-induced nephropathy

Lipid peroxidation in the kidney has been shown to precede proteinuria in puromycin aminonucleoside (PAN)-induced nephropathy. The aim of this study was to determine if L-2-oxothiazolidine-4-carboxylic acid (procysteine) would protect rats against PAN-induced nephrotoxicity. Male Sprague-Dawley rats were treated with procysteine (16 mg/100 g body weight i.p.) 24 h and 30 min prior to receiving a single injection of PAN (15 mg/100 g body weight i.v.) followed by procysteine in the drinking water (4 g/l). Control rats received procysteine alone (intraperitoneally and in drinking water) or PAN alone and then plain water. Proteinuria was not significantly different between PAN/ procysteine and PAN groups, reaching a maximum at day 14 and persisting at day 28. Lipid peroxidation was more severe in PAN/procysteine rats reaching a maximum at day 3 (253 +/- 30 ng/mg protein) compared to day 5 in PAN rats (196 +/- 20 ng/mg protein). Procysteine alone did not modulate proteinuria over 28 days or lipid peroxidation over 7 days. GSH levels over 7 days were not elevated by procysteine and were virtually zero in PAN and PAN/procysteine rats. Focal glomerulosclerosis (FGS) was worse at day 28 in PAN/procysteine rats than in PAN rats (39 +/- 8.2 vs. 23 +/- 4.5%; p < 0.05). This study shows that procysteine as a potential source of reducing equivalents does not protect against renal lipid peroxidation and FGS in this model. On the contrary, PAN/procysteine rats developed significantly more FGS through yet unknown mechanisms.

High-performance liquid chromatographic assay for common sunscreening agents in cosmetic products, bovine serum albumin solution and human plasma

This paper reports the development of a reversed-phase high-performance liquid chromatographic assay for quantifying five of the most common sunscreen agents, namely 2-ethylhexyl-p-dimethyl aminobenzoate (Escalol 507), 2-ethylhexyl-p-methoxycinnamate (Parsol MCX); 4-tert.-butyl-4'-methoxydibenzoylmethane (Parsol 1789), 2-hydroxy-4-methoxybenzophenone-3 (oxybenzone) and 2-ethylhexyl-salicylate (octylsalicylate). The assay permits analysis of the sunscreen agents in formulations and in biological fluids, including bovine serum albumin (BSA) solution, a common additive to in vitro skin diffusion cell receptor fluids, as well as human plasma. Separation was achieved using an ODS C154 column with a methanol-water (88:12) mobile phase. The analytes were detected by ultraviolet light absorption at a wavelength of 315 nm. The assay was linear with minimum detectable limits, calculated as greater than 3-times the baseline noise level: for oxybenzone and Escalol 507, 0.05 microgram/ml; for Parsol 1789 and Parsol MCX, 0.1 microgram/ml; for octylsalicylate, 1 microgram/ml. Recoveries from both plasma and 2% BSA were within the range 89-107%. The inter- and intra-day coefficients of variation for the five agents were not more than 4% at the upper end of the linear range and not more than 10% at the lower end. Preliminary stability studies of the sunscreen agents in a commercial product and in two diffusion cell receptor fluids were also conducted.

The limiting mobility of DNA sequencing fragments for both cross-linked and noncross-linked polymers in capillary electrophoresis: DNA sequencing at 1200 V cm-1

The mobility of DNA sequencing fragments was measured in Long-Ranger gels at an electric field ranging from 200 to 1200 V cm-1 and in noncross-linked polyacrylamide at electric fields ranging from 100 to 300 V cm-1. In both cases, N*, the fragment length that denotes the onset of biased reptation with orientation, is inversely proportional to electric field. The inverse dependence of N* is inconsistent with the original biased reptation model but is consistent with modern models of DNA migration. While separation speed increases dramatically with electric field, the number of bases determined in a separation decreases in proportion to field strength. We present a DNA sequencing run at an electric field of 1200 V cm-1. Roughly 200 bases of sequence are determined in 3.5 min.

Non-stochastic utilization of Ig V region genes in unselected human peripheral B cells

Limited evidence based on a few subjects suggests that human peripheral blood B cells may express a non-stochastic assortment of V region genes. To determine if non-stochastic utilization was a generally applicable rule, the identities of rearranged V region gene segments were determined in unselected peripheral blood B cells from 12 subjects (five male, seven female), ranging in age from 35 to 72 years. The analysis was limited to V region genes belonging to the VH3 gene family. More than 4500 independent VH3-containing rearrangements were analysed. The frequency of occurrence of eight individual VH3 gene segments contained in rearrangements was assessed using gene specific oligonucleotide probes. Usage of elements was not uniform. Three elements, which have been known to encode autoantibodies as well as to be frequently rearranged during fetal development, were represented among rearrangements more frequently than were other members of the VH3 family, and in aggregate, accounted for the majority of rearrangements. These three predominant loci are clustered in an 80 kb region suggesting an influence of chromosomal location on efficiency of rearrangement. The results document a clear, statistically significant, preference for the occurrence of specific V region genes among rearrangements. The modest amount of variation observed between subjects was not associated with either age or gender. Duplications which increased gene dose may have contributed to increased gene usage. These data indicate that, in caucasians, the immunoglobulin rearrangements in adult human B cells are dominated by a few heavy chain V region genes to the exclusion of other putatively equally functional genes. Thus, the conventional notion that the adult repertoire is normalized with respect to family complexity is not confirmed by analysis of individual VH genes.

Use of non-cross-linked polyacrylamide for four-color DNA sequencing by capillary electrophoresis separation of fragments up to 640 bases in length in two hours

Four-color DNA cycle sequencing was performed on an M13mp18 template using dye-labeled primers. Sequencing fragments were separated by capillary electrophoresis at 60 degrees C and at an electric field of 150 V/cm. The sieving medium was 5%T, non-cross-linked polyacrylamide in 7 M urea. The use of high temperature for the separation reduces formation of secondary structures in the sequencing fragments, generating a sequence that is free of compressions without the use of strongly denaturing gels. The use of high temperatures also increases the separation rate compared with room-temperature operation. Fragments up to 640 bases are separated in less than 2 h.

Expression of syndecan-1 changes during the differentiation of visceral and parietal endoderm from murine F9 teratocarcinoma cells

F9 teratocarcinoma stem cells treated with retinoic acid differentiate in suspension into embryoid bodies with an outer layer of visceral endoderm surrounding a core of largely undifferentiated cells. The visceral endoderm-containing embryoid bodies, when plated onto an extracellular matrix coating, give rise to parietal endoderm outgrowth. These in vitro cell cultures mimic both geometrically and biochemically the differentiation of visceral and parietal endoderm in the early mouse embryo and, thus, were used as a model system for the study of molecular and cellular mechanisms underlying the differentiation of the extraembryonic endoderm lineages. We have investigated the expression of syndecan-1, an integral membrane proteoglycan that binds to multiple components of the extracellular matrix and basic FGF, during visceral endoderm differentiation and parietal endoderm outgrowth. Syndecan-1 immunostaining is detected on all cell surfaces in the undifferentiated embryoid bodies and in the differentiating embryoid bodies prior to the formation of the visceral endoderm. Following the differentiation of visceral endoderm, syndecan-1 localizes predominantly to the basal surface of this epithelial layer, while syndecan-1 staining in the core of differentiated embryoid bodies is faint. Quantitation of cell associated syndecan-1 indicates that syndecan-1 is down-regulated during embryoid body differentiation. However, northern analysis shows that the amounts of steady-state syndecan-1 mRNA are the same in undifferentiated versus differentiated embryoid bodies, suggesting post-transcriptional regulation of syndecan-1 expression in the differentiating embryoid body. Analysis of syndecan-1 distribution in the outgrowth culture by immunofluorescence demonstrates that syndecan-1 is absent from the cell surface of parietal endoderm. However, a substantial amount of syndecan-1 is detected inside parietal endoderm cells. While all three cell types release syndecan-1 ectodomain into the culture medium, the parietal endoderm outgrowth releases more syndecan-1 ectodomain than the differentiated embryoid body. These data suggest that the post-transcriptional control and post-translational shedding of syndecan-1 from the cell surface are developmentally regulated during the differentiation of visceral to parietal endoderm and the migration of parietal endoderm.

Loss of allosteric behaviour in recombinant hemoglobin alpha 2 beta 2(92)(F8) His-->Ala: restoration upon addition of strong effectors

In the stereochemical model proposed by Perutz [1], the Fe-His(F8) bond plays a significant role in the allosteric transition in hemoglobin and the resulting cooperativity in ligand binding. When this bond is ruptured, there is a loss in the transmission of the information concerning ligand binding; examples are Hb(NO)4 in the presence of inositol hexakisphosphate (IHP), or nickel substituted Hb hybrids which, despite being liganded, exhibit deoxy-like properties. To study the effects of the loss of the iron proximal histidine bond, we have engineered the alpha 2 beta 2(F8)H92A recombinant Hb. The replacement of the highly conserved proximal histidine F8 residue by an alanine results in a low affinity for the heme group and a loss of the allosteric properties; kinetics of CO recombination after photodissociation show only the rapid bimolecular phase, characteristic of the high affinity R-state. However, a significant amount of deoxy (T-state) kinetics are observed after addition of external effectors such as IHP. The iron-histidine bond is apparently crucial for the heme-heme interaction, but the allosteric equilibrium may still be influenced by external constraints.

Stability of hydrocortisone oral suspensions prepared from tablets and powder

OBJECTIVE

To assess the stability, dosage uniformity, and clinical acceptability of hydrocortisone oral suspensions prepared from tablets and powder.

DESIGN

Hydrocortisone 2.5 mg/mL oral suspensions were stored in the dark for 91 days at 5, 25, and 40 degrees C. Dosage uniformity was assessed by repeated sampling of the formulation prepared from tablets at 5 and 25 degrees C. The formulation was clinically evaluated in 2 pediatric patients.

SETTING

A university pharmacy school and affiliated urban teaching hospital.

PARTICIPANTS

A brother (4 y old) and sister (1 y old) with congenital adrenal hyperplasia maintained on a commercially available hydrocortisone cypionate suspension.

MAIN OUTCOME MEASURES

Samples removed at 5 time points were analyzed for hydrocortisone to assess decomposition over 90 days. Dosage uniformity was evaluated by intra- and interday variability. Palatability was examined in the 2 children and urinary cortisol concentrations were measured in the boy before and 5 days after commencing the formulation prepared from tablets.

RESULTS

Decomposition of hydrocortisone was not significant except in the formulation that was prepared from tablets and stored at 40 degrees C. Dosage uniformity gave coefficients of variation less than 4.5%. The formulation was well-tolerated and resulted in satisfactory urinary cortisol concentrations in the boy.

CONCLUSIONS

The hydrocortisone oral suspensions supply a uniform dose and are chemically stable when stored in the dark at 5 and 25 degrees C for at least 30 days. They provide flexible and convenient dosage forms for pediatric patients.

STD1 (MSN3) interacts directly with the TATA-binding protein and modulates transcription of the SUC2 gene of Saccharomyces cerevisiae

STD1 (MSN3) was isolated independently as a multicopy suppressor of mutations in the TATA-binding protein and in SNF4, suggesting that STD1 might couple the SNF1 kinase signaling pathway to the transcriptional machinery. We report here a direct physical interaction between STD1 and the TATA-binding protein (TBP), observed in vivo by the two-hybrid system and in vitro by binding studies. STD1 bound both native TBP in yeast cell-free extracts and purified recombinant TBP. This interaction was altered when TBP delta 57 was used, suggesting a role for the non-conserved N-terminal domain of TBP in mediating protein-protein interactions. We also show that perturbation of STD1-TBP stoichiometry alters SUC2 expression in vivo and that this effect is dependent on the N-terminal domain of TBP. The activation of SUC2 expression by increased copy number of STD1 occurs at the level of mRNA accumulation and it requires the same TATA element and uses the same transcription start site as does activation of SUC2 by glucose limitation. Taken together, these results suggest that STD1 modulates SUC2 transcription through direct interactions with TBP.