Immunostimulation by Alsophila spinulosa extract fraction VII of both humoral and cellular immune responses

Alsophila spinulosa (Cyatheaceae) has been used in Asia as a herbal medicine. In this study, the immunomodulatory effects of Alsophila spinulosa dried stems water extract fraction VII (AS-VII) were studied in vitro using an animal model. The results showed that AS-VII stimulated splenocyte proliferation in both BALB/c and C3H/HeJ mice. By cell fractionation analysis, the results showed that the mitogenic effect of AS-VII was predominantly on B cell population. The antibody response was also augmented by AS-VII in BALB/c and C3H/HeJ mice. The augmentation of immune responses in C3H/HeJ, the lipopolysaccharide (LPS)-hyporesponsive mouse strain, indicated that the activity was not simply due to the LPS contamination which may be present in AS-VII preparation. Furthermore, AS-VII caused an increase in cytotoxic T cell activity in a mixed lymphocyte reaction culture. These data indicate that AS-VII possesses the capability of augmenting both humoral and cellular immune responses.

The surface density gradient of grafted poly (ethylene glycol): preparation, characterization and protein adsorption

A surface density gradient of grafted poly (ethylene glycol) (PEG) chains was prepared using two-phase silanization of a flat silica surface. The first step was to create the surface density gradient of isocyanatopropyldimethylsilyl groups and to hydrolyze the isocyanato moiety into an amine. These surface amines were reacted with an excess of aldehyde-terminated PEG. The PEG-silica surface was characterized by dynamic contact angle measurements, X-ray photoelectron spectroscopy and ellipsometry. The length of the PEG gradient region was approximately 7 mm and the thickness in air ranged from zero to 1.1 nm. The maximum surface density of the PEG layer, as calculated from ellipsometric data, amounted to an average 0.4 PEG (molecular weight Mw = 2000 Da) molecule nm-2, while the surface density average of the amine groups was 1.4 molecules nm-2, indicating that only a fraction of the surface amines reacted with aldehyde-terminated PEG. The PEG segment density profile in the gradient PEG region was computed by a self-consistent mean field theory. The PEG (Mw = 2000 Da) segments profile was not parabolic, but showed a thin depletion zone next to the surface. The influence of the surface density of the grafted PEG chains on protein repellence was tested by the adsorption of fibrinogen from solution and from a ternary protein solution mixture containing fibrinogen, albumin and immunoglobulin G. Fibrinogen adsorption onto the silica end of the gradient was extremely low, both in the presence of the other two proteins and in their absence. As the surface density of the grafted PEG chains increased, so did the fibrinogen adsorption (up to 0.024 μg cm-2). It is not clear whether this low fibrinogen adsorption resulted from the interactions of the protein with the grafted PEG chains or with residual surface amines that were available due to some imperfections in the grafted PEG layer.

Effects of baicalein and esculetin on transduction signals and growth factors expression in T-lymphoid leukemia cells

The possible mechanisms of antiproliferative effect of baicalein were studied in human T-lymphoid leukemia cells (CEM cells) and compared with those of esculetin. Baicalein, esculetin and related compounds, baicalein, wogonin, esculin and scoparone, inhibited CEM cell proliferation. Baicalein exhibited the greatest antiproliferative activity with an IC50 of 4.7 +/- 0.5 microM and the maximal suppression of 91.5 +/- 1.4% in CEM cells. The protein tyrosine kinase activity in the CEM cells was significantly reduced by baicalein (10(-6)-10(-4) M) and esculetin (10(-4) M). Baicalein exhibited a greater inhibitory activity on the protein tyrosine kinase than did esculetin (74.1 +/- 3.3% vs. 64.6 +/- 2.8% inhibition at 10(-4) M). On the other hand, the protein kinase C activity stimulated by phorbol-12-myristate 13-acetate was reduced by directly incubating with baicalein (10(-6)-10(-4) M) and esculetin (10(-4) M). However, the inhibitory activities on protein kinase C did not show a dose-dependency. The reverse transcription-polymerase chain reaction analysis of platelet-derived growth factor-A (PDGF-A) and transforming growth factor-beta 1 (TGF-beta 1) messenger RNA levels demonstrates that baicalein and esculetin reduced the PDGF-A mRNA level, but less affected the TGF-beta 1 mRNA. Baicalein exhibited the greater reduction on the expression of PDGF-A mRNA than did esculetin. It is suggested that baicalein and esculetin may affect cell proliferation by direct inhibition of growth-related signal, protein tyrosine kinase, as well as reduction of mRNA expression of growth factor, platelet-derived growth factor.

Variation in mitochondrial DNA and population structure of the Taipei treefrog Rhacophorus taipeianus in Taiwan

Mitochondrial DNA (mtDNA) from 40 samples of the Taipei treefrog Rhacophorus taipeianus collected from seven populations in Taiwan were sequenced to document the DNA sequence variation in anuran mtDNA and to elucidate the phylogeographic population structure in the Taipei treefrog. Sequences of 722-764 bases in length, including a 108-bp segment of the cytochrome b gene and a 614-656-bp D-loop segment, were obtained by direct sequencing using polymerase chain reaction (PCR). The variation in length was due to a 40-bp region that tandemly repeated four to five times in the D-loop region. The first repeat is the most conserved one among the five repeats because there are no variable sites in this repeat. Besides the 40-bp length variation, 28 positions in the 764-bp sequences are variable and distributed evenly in the cytochrome b gene fragment and D-loop region. Variation in the D-loop of the Taipei treefrog is comparable to those of other vertebrates. Two well-differentiated lineages (northern and central) differing by mean sequence divergence of 1.7% are identified and concordant with their geographic distributions. The two lineages are inferred to have split from a common ancestral population in the early Pleistocene. However, the interpopulation divergence of the northern lineage (< 0.33%) is apparently lower than that of the central lineage (1.11%), implying that the two lineages evolved independently and had different demographic histories after divergence. This study reveals that anuran D-loop has potential as a genetic marker in phylogenetic and population genetic analyses of anurans.

[Cyclocryotherapy for refractory glaucoma after penetrating keratoplasty]

Twenty-eight patients (28 eyes) with secondary glaucoma following penetrating keratoplasty and failed to respond to anti-glaucoma drugs and routine filtering procedures were performed with cyclocryotherapy by nitrogen monoxide. All patients were followed up for more than one year. The results showed intraocular pressure was well controlled in 89% of the eyes, graft remained clear in 85%, and visual functions are preserved in 82% of the patients. Our study suggests that precisely controlled temperature, time, and extent of cryotherapy, and post-operative anti-rejection agents be the key factor to success. Over-treatment, which may lead to atrophy of the eye, must be avoided. It should not be given up flowing under-treatment in the initial procedure.

Sepsis-induced apoptosis of the thymocytes in mice

Intraperitoneal injection of Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) induces thymic atrophy in mice. The thymus weight, cell number, and viability began to decrease at 3 h, and reached their lowest level at 72 h. The thymocyte death was associated with DNA fragmentation of approximately 200 base pairs in ladder form. The kinetic study on histopathology revealed the process of thymocyte death and thymic atrophy. Flow-cytometric analysis showed that CD4+CD8+ thymocytes decreased predominantly. LPS caused thymocyte apoptosis, but only in LPS-responder mice, unlike Gram-negative bacteria that induced apoptosis in both LPS-responder (C3H/HeN) and LPS-nonresponder (C3H/HeJ). Gram-positive bacteria Streptococcus pneumoniae also caused apoptosis in LPS-nonresponder (C3H/HeJ) and LPS-responder mice (B6). The kinetics of serum TNF-alpha production after Gram-negative or Gram-positive bacteria injection was slightly different. E. coli induced serum TNF-alpha peak at 1 h in B6 mice, whereas S. pneumoniae induced a peak at 6 h in C3H/HeJ and at 9 h in B6 mice. Similarly, S. pneumoniae induced thymocyte apoptosis around 9 to 12 h, which was 6 to 9 h later than that observed with E. coli in B6 mice. Anti-TNF-alpha Ab completely blocked the E. coli-induced thymocyte apoptosis, but was only partially inhibitory on the S. pneumoniae-induced thymocyte apoptosis. Furthermore, thymocyte apoptosis induced by E. coli was inhibited by cycloheximide or actinomycin D. These data indicate that both Gram-negative and Gram-positive bacteria could induce thymus atrophy via apoptosis, and that TNF-alpha is a common denominator released and might be responsible for the thymocyte apoptosis.

Sepsis-induced apoptosis of the thymocytes in mice

Intraperitoneal injection of Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) induces thymic atrophy in mice. The thymus weight, cell number, and viability began to decrease at 3 h, and reached their lowest level at 72 h. The thymocyte death was associated with DNA fragmentation of approximately 200 base pairs in ladder form. The kinetic study on histopathology revealed the process of thymocyte death and thymic atrophy. Flow-cytometric analysis showed that CD4+CD8+ thymocytes decreased predominantly. LPS caused thymocyte apoptosis, but only in LPS-responder mice, unlike Gram-negative bacteria that induced apoptosis in both LPS-responder (C3H/HeN) and LPS-nonresponder (C3H/HeJ). Gram-positive bacteria Streptococcus pneumoniae also caused apoptosis in LPS-nonresponder (C3H/HeJ) and LPS-responder mice (B6). The kinetics of serum TNF-alpha production after Gram-negative or Gram-positive bacteria injection was slightly different. E. coli induced serum TNF-alpha peak at 1 h in B6 mice, whereas S. pneumoniae induced a peak at 6 h in C3H/HeJ and at 9 h in B6 mice. Similarly, S. pneumoniae induced thymocyte apoptosis around 9 to 12 h, which was 6 to 9 h later than that observed with E. coli in B6 mice. Anti-TNF-alpha Ab completely blocked the E. coli-induced thymocyte apoptosis, but was only partially inhibitory on the S. pneumoniae-induced thymocyte apoptosis. Furthermore, thymocyte apoptosis induced by E. coli was inhibited by cycloheximide or actinomycin D. These data indicate that both Gram-negative and Gram-positive bacteria could induce thymus atrophy via apoptosis, and that TNF-alpha is a common denominator released and might be responsible for the thymocyte apoptosis.

The chromosomal DNA of Streptomyces lividans 66 is linear

Two copies of a DNA sequence similar or identical to one end of the linear plasmid SLP2 were found on the Streptomyces lividans chromosome. Restriction mapping showed that these sequences represented free ends. Electrophoretic retardation and glass-binding studies indicated that the telomeres carry covalently bound proteins. Moreover, the chromosome migrated as an 8 Mb linear DNA in pulsed-field gel electrophoresis. A similar finding with the chromosomes of six other Streptomyces species suggested that a linear chromosome may be characteristic of the genus. The S. lividans chromosome can be circularized by joining the two ends by artificial targeted recombination or by spontaneous deletions spanning both telomeres. Thus the chromosome appears to be able to exist, in viable bacteria, as a linear or a circular molecule.

Renovascular actions of angiotensin II in the isolated kidney of the rat: relationship to lipoxygenases

Several actions of angiotensin II have been linked to metabolism of arachidonic acid by lipoxygenases. To evaluate the importance of this interaction intrarenally we tested the effect of three different lipoxygenase inhibitors, BW755c (50 microM), a dual lipoxygenase-cyclooxygenase inhibitor, MK447 (200 microM), a nonselective lipoxygenase inhibitor which can stimulate cyclooxygenase, and baicalein (1 microM), a highly selective 12-lipoxygenase inhibitor, on angiotensin II-evoked hemodynamic changes in the rat isolated kidney, perfused with oncotic agents. Kidneys were pretreated with indomethacin (10 microM) to exclude participation of cyclooxygenase-dependent arachidonate products. Renal perfusion pressure was kept constant at 90 mm Hg by continuous adjustments in perfusate flow rate. Inhibition of cyclooxygenase alone produced a transient potentiation of the vasoconstrictor response to angiotensin II without altering GFR. On the other hand, the lipoxygenase inhibitors attenuated the angiotensin II-induced increase in renal vascular resistance by approximately 50% and promoted an increase in GFR above that of kidneys infused with angiotensin II in the presence of only indomethacin. Base-line values were essentially unchanged by lipoxygenase inhibition. Furthermore, the vasoconstrictor response to the thromboxane/endoperoxide agonist U46619 was unaffected. We conclude that products of the lipoxygenase pathway, arising within the kidney, contribute to the renal hemodynamic effects of angiotensin II.

Medical treatment of uterine myoma with long-acting gonadotropin-releasing hormone agonist prior to myomectomy

A less bulky uterine myoma is technically easier to deal with during surgery. Recently gonadotropin-releasing hormone agonists (GnRH-a) have been used for the purpose of medical hypophysectomy, thereby reducing the size of uterine myomas. Ten premenopausal women with infertility and intramural-submucous myoma manifesting with menorrhagia and obstruction of the tubal ostia were recruited for this study. A long-acting depot GnRH-a, Decapeptyl, was given intramuscularly every four weeks for three months as an adjunct prior to myomectomy. Luteinizing hormone, follicular stimulating hormone and estradiol declined to the menopausal range following treatment. The size of the myoma decreased to a mean of 32.3 +/- 13.3% of the original volume. Myomectomy was performed in eight patients at the end of the study. Remarkably little blood loss was observed during the surgery. All of the patients had their uteri preserved, and six out of eight patients achieved pregnancy within 12 months after surgery. Our results indicate that monthly administration of long-acting GnRH-a significantly reduces the myoma volume and makes myomectomy technically easier to perform with the possibility of reduced complication rates and better preservation of future fertility.

The conjugative plasmid SLP2 of Streptomyces lividans is a 50 kb linear molecule

The SLP2 plasmid had previously been demonstrated genetically to exist in Streptomyces lividans by its ability to promote conjugation and to elicit 'pocks' on recipient (SLP2-) cultures, but it had not been physically detected. Using pulsed-field gel electrophoresis, a 50 kb linear DNA was isolated from SLP2+ but not SLP2- strains of S. lividans, and from Streptomyces coelicolor and Streptomyces parvulus strains to which SLP2 had been transferred by conjugation or transformation. We conclude that this linear DNA is SLP2. The terminal fragments of SLP2 were cloned. The determined sequences revealed a 44bp imperfect terminal inverted repeat. The terminal 12bp sequence of SLP2 was identical to those of two other Streptomyces linear plasmids, pSLA2 and pSCL, and similar to the terminal sequences of another Streptomyces linear plasmid, SCP1. The termini of SLP2 DNA were resistant to digestion by lambda exonuclease and ExoIII. A truncated (probably crippled) copy of Tn4811 is present on the plasmid. While the SLP2 plasmid exists as a free form in the host, a 15.7 kb sequence corresponding to the segment of SLP2 from Tn4811 to the right terminus is also present (at a copy number similar to the free form) elsewhere in the genome of S. lividans. Furthermore, SLP2 is partially homologous to a newly discovered 650 kb linear plasmid in S. parvulus.

The effect of chronic and acute exercise on immunity in rats

The effects of exercise training and acute exercise on the immune system were investigated in rats. For chronic exercise training, the rats ran on a drum exerciser at the intensity of about 60-70% of maximal oxygen consumption (VO2max) for 30 min and then extended up to 60 min per day, 5 days per week for 10 weeks. The rats were at rest for 3 days before sacrifice. The mitogenic activity of spleen lymphocytes to concanavalin A (Con A) and staphylococcal enterotoxin B (SEB) decreased as compared to the sedentary control, while proliferative response to lipopolysaccharide (LPS) increased. The interleukin-2 (IL-2) production in the training group was reduced. The immunomodulatory effect after acute exercise has also been investigated and it showed profound enhancement of cell proliferation to Con A, SEB and LPS in mild (50% VO2max for 10 min) and moderate (70% VO2max for 10 min) exercise groups. The enhancing activity was less prominent after severe exercise (> 75%) VO2max until exhaustion). The IL2 production increased in all of these acute exercise groups. Nevertheless, there was no significant variation between exercise and control groups in the cell number per spleen and the percentages of various lymphocyte populations, i.e., total T, CD4+, CD8+ and IL-2R+ T cells as well as B cells. In summary, this study indicates that chronic exercise training may cause the reduction of T cell activity while acute exercise manifests an enhancing effect. However, B cell proliferation was elevated in both chronic and acute exercise groups.

Prediction of fetal macrosomia by single ultrasonic fetal biometry

A total of 1,056 fetuses underwent single ultrasonographic measurement of fetal biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and estimated body weight within five days of delivery. The accuracy of these parameters and estimated body weight equations in the prediction of macrosomia (birth weight > or = 4,000 g) was evaluated. With the use of receiver operator characteristic curves, the optimal cutoff value for each parameter with the best sensitivity, specificity and accuracy was selected. BPDs > or = 9.4 cm had the best sensitivity (68.8%), specificity (74.3%), and accuracy (74.1%). ACs > or = 35 cm had the best sensitivity (81.3%), specificity (81.5%), and accuracy (81.5%). FLs > or = 7.0 cm had the best sensitivity (68.8%), specificity (74.5%), and accuracy (74.3%). The estimated body weight equations did not increase the prediction values whether or not FL was included. Both had the same prediction values at > or = 3,700 g, ie, sensitivity (71.9% vs 71.9%), specificity (92.1% vs 93.8%), and accuracy (91.5% vs 93.2%). The results showed AC to be the best single parameter for predicting macrosomia. Combinations of these parameters were better than a single parameter in the prediction of macrosomia.

Chloride anion concentration as a determinant of renal vascular responsiveness to vasoconstrictor agents

1. The role of chloride concentration in modulating vasoconstrictor responses of the rat isolated kidney, perfused with Krebs-Henseleit solution, to angiotensin II (AII), arginine vasopressin (AVP) and phenylephrine (PE) was investigated. 2. Reduction of perfusate chloride from a high (117 mM) to low (87 mM) concentration, by substitution of sodium chloride with a mixture of sodium salts of propionate, acetate and methanesulphonate, reduced responsiveness to all three vasoconstrictors, the change for AII being most pronounced. 3. For AII, reduced vasoactivity with low chloride was evident both in terms of the threshold dose and on the linear part of the dose-response curve but not for the maximum response. This attenuating effect of low chloride on the vasoconstrictor response to AII was reversed when perfusion with high chloride was reinstituted. Continuous perfusion with high chloride progressively increased the vasoconstrictor effect of low doses of AII for successive dose-response curves. 4. In addition to reducing responses on the linear part of the dose-response curve for both AVP and PE, low chloride also reduced the maximum vasoconstrictor response to PE, whereas the threshold dose for the two agonists was unchanged. In contrast to the enhanced pressor response to AII, during continuous perfusion with high chloride, tachyphylaxis occurred with AVP and PE. 5. The ability of chloride to modify renal responsiveness to vasoconstrictor agents may contribute to the increase in renal vascular resistance and decrease in glomerular filtration rate (GFR) which occurs during infusion of hyperchloremic solutions into the renal artery and explain the need for chloride as the anion accompanying sodium in salt-sensitive hypertensive models.

In vivo induction of apoptosis in immature thymocytes by staphylococcal enterotoxin B

Staphylococcal enterotoxins are potent T cell mitogens. Recent studies have shown that the binding of these toxins to class II MHC molecules on accessory cells is essential for the stimulation of T cells which bear specific V beta segment of TCR. In the present study we show that i.v. administration of staphylococcal enterotoxin B (SEB) results in an enlargement of spleen and lymph nodes but causes thymus atrophy. Elimination of CD4+CD8+ cells predominantly accounted for the shrinkage of thymus, and the lowest level of this cell population was reached 4 days after SEB injection. Furthermore, this decrease in CD4+CD8+ cells was accompanied by a relative increase in the percentages of CD4+CD8-, CD4-CD8+ and CD4-CD8- cells, whereas their absolute numbers actually reduced on day 4. The thymus shrinkage involved apoptosis which was characterized by DNA fragmentation and morphologic changes. The depletion of Thy-1 high, TCR-alpha beta low and TCR-alpha beta intermediate cells also occurred with a kinetic correlated to the reduction of CD4+CD8+ cells. Our results further showed that the percentages of V beta 8+ cells reduced 12 h post SEB injection, increased after 2 days, and decreased again thereafter. SEB thus causes both apoptotic and stimulative effects in the thymus. Apparently, the tremendous loss of double-positive cells (greater than 90% in cell number on day 4) is not simply due to the reduction of V beta 8+ cells, the possible modulatory effect of other factors or hormones which may play a role in the cell death is discussed.

In vivo induction of apoptosis in immature thymocytes by staphylococcal enterotoxin B

Staphylococcal enterotoxins are potent T cell mitogens. Recent studies have shown that the binding of these toxins to class II MHC molecules on accessory cells is essential for the stimulation of T cells which bear specific V beta segment of TCR. In the present study we show that i.v. administration of staphylococcal enterotoxin B (SEB) results in an enlargement of spleen and lymph nodes but causes thymus atrophy. Elimination of CD4+CD8+ cells predominantly accounted for the shrinkage of thymus, and the lowest level of this cell population was reached 4 days after SEB injection. Furthermore, this decrease in CD4+CD8+ cells was accompanied by a relative increase in the percentages of CD4+CD8-, CD4-CD8+ and CD4-CD8- cells, whereas their absolute numbers actually reduced on day 4. The thymus shrinkage involved apoptosis which was characterized by DNA fragmentation and morphologic changes. The depletion of Thy-1 high, TCR-alpha beta low and TCR-alpha beta intermediate cells also occurred with a kinetic correlated to the reduction of CD4+CD8+ cells. Our results further showed that the percentages of V beta 8+ cells reduced 12 h post SEB injection, increased after 2 days, and decreased again thereafter. SEB thus causes both apoptotic and stimulative effects in the thymus. Apparently, the tremendous loss of double-positive cells (greater than 90% in cell number on day 4) is not simply due to the reduction of V beta 8+ cells, the possible modulatory effect of other factors or hormones which may play a role in the cell death is discussed.

Comparison of umbilical blood gas and acid-base status of small-for-date and normal Chinese newborns

A prospective study of umbilical arterial blood gas in appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) babies was performed at our hospital from August 1989 to July 1990. A total of of 512 cases were included, 432 cases in the AGA group and 80 cases in the SGA group, with gestational ages ranging from 26 to 42 weeks. Umbilical arterial blood was collected immediately after delivery of the newborns. Comparisons of maternal age, gestational age, birth body weight and body length of infants. Apgar scores at one minute and five minutes, cord arterial blood pH, pO2, pCO2, base excess, bicarbonate, total CO2, O2 saturation and O2 content between the AGA and SGA groups were taken into account. Our results demonstrated significant differences in birth body weight, birth body length, Apgar scores at one minute and five minutes and gestational age in the SGA group compared with those in the AGA group. The parameters of cord arterial blood gas were not correlated with gestational age in either group. The mean pH value in the AGA group (7.30 +/- 0.05) was higher than that in the SGA group (7.28 +/- 0.08). The same trend of difference was also noted between the AGA (7.30 +/- 0.04) and SGA (7.27 +/- 0.07) babies who were delivered by Cesarean section (p < 0.05). The latter results imply a more academic state in SGA babies which is independent of labor. Prepartum asphyxia plays an important role in determining the prognosis of SGA babies. We suggest routine umbilical cord blood gas and acid-base analysis at delivery to assess fetal asphyxia.

Immunomodulatory activity of various fractions derived from Physalis angulata L extract

The immunomodulatory effects of Physalis angulata L. extract fraction VII (PA-VII), PA-VII-A, PA-VII-B and PA-VII-C were investigated in this study. The results showed that PA-VII and PA-VII-C strongly enhanced blastogenesis response, PA-VII-B had moderate activity, and PA-VII-A exerted only slight effect on cell proliferation. A synergistic effect was observed when the suboptimal dosage of phytohemagglutinin (PHA) or lipopolysaccharide (LPS) was added to the culture. Furthermore, PA-VII and PA-VII-C possessed stimulatory activity on B cells and less effect on T cells. The antibody responses were also augmented by PA-VII, PA-VII-B and PA-VII-C, but not by PA-VII-A. The enhancement of antibody response could be observed both in BALB/c and C3H/HeJ mice.

Adsorption of complement proteins on surfaces with a hydrophobicity gradient

Activation of the complement system is recognized as one of the major problems with respect to biocompatibility of biomaterials. The binding of C3 (central component of complement) and B (factor B, an activator of C3), and H (factor H, an inhibitor of C3 activation) plays a crucial role in the activation of the alternative pathway of complement on the surfaces of biomaterials during extracorporeal procedures. Here we report on the adsorption of C3, B or H on to the silica surface with a hydrophobicity gradient. The amount of native 125I-C3 bound to both hydrophilic and hydrophobic surfaces was very similar (0.8 and 0.9 micrograms/cm2; 4 x 10(-12) mol/cm2). Neither factor H nor factor B was able to displace already adsorbed 125I-C3 from either of the surfaces. The extent of binding of factors B and H to preadsorbed C3 was a function of the surface hydrophobicity: more 125I-B or 125I-H was bound to C3 adsorbed at the hydrophilic end than at the hydrophobic end of the gradient surface. The binding of 125I-B or 125I-H to preadsorbed C3 appeared to be influenced by the availability of their binding sites on adsorbed C3 molecules rather than by the amount of surface-bound C3. At the hydrophobic end of the gradient surface the molar binding ratio of B/C3 was considerably smaller than the molar binding ratio of H/C3. It can be speculated that the hydrophobicity of the surface determines orientation and/or conformation of adsorbed C3 molecule; when adsorbed at the hydrophobic end of the gradient, C3 molecule predominantly exposes the binding site to which only factor H can bind.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical validation of two equations in antenatal prediction of Chinese fetal weight by ultrasonography

The purpose of this series is to prospectively validate the Chinese equations for predicting fetal weight developed in a previous study. A total of 640 Chinese fetuses were examined antenatally for biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) by real-time ultrasonography within two days of delivery. The results showed the actual birth weight (BW) to be highly correlated with the estimated body weight for both the equation using BPD and AC (EBW1) (r = 0.888, p less than 0.0001) and the equation using BPD, AC and FL (EBW2) (r = 0.890, p less than 0.0001). Our results demonstrate that the Chinese equations developed by Hsieh et al are a better fit for Chinese fetuses than the foreign equations are. Also, the two Chinese equations predict fetal weight well between 2,000 g and 4,000 g, but further modification is needed in cases where the BW is less than 2,000 g or greater than 4,000 g.

Utilization of methoxylated aromatic compounds by the acetogen Clostridium thermoaceticum: expression and specificity of the co-dependent O-demethylating activity

The aromatic CO-dependent O-demethylating activity of Clostridium thermoaceticum was evaluated. Secondary aromatic substituent groups (-OH, -CO2H, -CH2OH, and -OCH3) were critical to O demethylation. O-demethylating activities and specificities were similar from cells grown at the expense of different methoxylated aromatic compounds; all O-methyl-grown cells catalyzed the same sequential O demethylation of multi-methoxylated compounds, suggesting that a broad specificity O demethylase was involved in O demethylation. In cell-fractionation studies, CO-dependent O demethylation was catalyzed by membrane-associated components.

Binding of general transcription factor TFIIB to an acidic activating region

A central issue in eukaryotic transcriptional regulation is the mechanism by which promoter-specific transcription factors (activators) stimulate transcription. Two lines of evidence indicate that the general transcription factor TFIIB is a pivotal component in the mechanism by which an acidic activator functions. First, during assembly of the preinitiation complex TFIIB binding is a rate-limiting step enhanced by an acidic activator. Second, the TFIIB activity in a HeLa cell nuclear extract is specifically retained on a column containing an acidic activating region. But because our previous study monitored only TFIIB activity, it remains possible that the interaction between TFIIB and the acidic activating region is mediated through additional proteins, for example, those designated as adaptors, coactivators or mediators. A complementary clone encoding TFIIB has recently been isolated and shown to encode a polypeptide of relative molecular mass 35,000. Here we report that TFIIB expressed in and purified from Escherichia coli (recombinant TFIIB) binds directly to the potent acidic activating region of the herpes simplex virus-1 VP16 protein.

Fetal alcohol syndrome: report of a case

Fetal alcohol syndrome is an uncommon occurrence in Taiwan, especially in the southern area. We report here a case who demonstrated severe intrauterine growth retardation with major limb reduction, chest hypoplasia and characteristic facial dysmorphism-short palpebral fissures, hypoplastic philtrum, and a thin upper lip. The mother had been consuming large quantities of alcohol, 6 bottles of "rice wine" per day (800 grams of absolute alcohol per day) during the pregnancy. The maternal serum level of ethanol was as high as 173 mg/dl. According to previous reports, we causally suggest that maternal ethanol abuse may be related to fetal anomalies in this case.

Mechanism of action of an acidic transcriptional activator in vitro

Transcription of a eukaryotic structural gene by RNA polymerase II requires the ordered assembly of general transcription factors on the promoter to form a pre-initiation complex. Here we analyze affinity-purified complexes at various stages of assembly to determine the mechanism of action of an acidic transcriptional activator. We show that the activator can function in the absence of ATP and stimulates transcription by increasing the number of functional preinitiation complexes. The activator effects this increase by recruiting the general transcription factor TFIIB to the promoter. Using protein affinity chromatography we demonstrate a specific interaction between an acidic activating region and TFIIB. Based on these combined results, we propose that TFIIB is a direct target of an acidic activator.

Inhibition of the delayed-type hypersensitivity response by staphylococcal enterotoxin B-induced suppressor T cells

Staphylococcal enterotoxin B (SEB) is a member of a family of gram-positive bacterial exotoxins which act as superantigens in both mouse and man. The administration of this toxin has been shown to inhibit antibody responses in vivo. We have previously shown that SEB is a potent inducer in vitro of multiple T suppressor cell populations. The present studies show that administration of microgram quantities of this toxin result in a reduced capacity to manifest a delayed-type hypersensitivity (DTH) response. In addition, we find that the failure to generate a normal DTH response appears to be due to the generation of a T suppressor cell population following SEB administration. Adoptive transfer studies show that the suppressor cells bear the CD5+ I-J+ CD4- CD8- Thy 1+ surface phenotype. The relationship of these cells to suppressor T cell populations generated following in vitro activation by SEB is discussed.

Immunosuppressive activity of staphylococcal enterotoxin B. II. Activation of suppressor-effector cells by a staphylococcal enterotoxin B-induced suppressor factor

The capacity of staphylococcal enterotoxins to stimulate all T cells bearing certain T cell receptors has recently generated a great deal of interest. These toxins are believed to bind directly both to the TCR:CD4 complex via its V beta domains and to class II MHC molecules on accessory cells prior to T cell activation. Previous studies from this laboratory have demonstrated that staphylococcal enterotoxin B (SEB) is capable of inducing multiple T suppressor cell populations which can inhibit in vitro antibody responses. Additional studies have demonstrated that the suppressive activity of these cells is mediated, at least in part, by an I-J-restricted suppressor factor. Efforts to characterize the inhibitory activity of this factor have demonstrated that the suppressive element is capable of activating both early and late acting suppressor cell populations in vitro. Analysis by both positive and negative selection shows that cells bearing the Lyt1-2+ surface marker phenotype are active early, whereas Lyt1+2+ cells are active both early and late in the antibody response. Additional experiments using various strains of mice as sources of suppressor factor and of naive splenocyte populations have demonstrated that activation of suppressor-effector cells by this suppressor factor is restricted at the I-J, but not Igh, gene locus. These studies suggest that this SEB-induced suppressor factor alone provides the signals necessary for the induction and activation of suppressor-effector cell activity.

Immunosuppressive activity of staphylococcal enterotoxin B. I. Characterization of staphylococcal enterotoxin-B-induced suppressor cells

Staphylococcal enterotoxin B (SEB) binds specifically to major histocompatibility complex class II molecules on the surface of accessory cells and stimulates virtually all T cells bearing certain, but not all, T cell-receptor V beta alleles. We have previously shown that this superantigen is a potent inducer of multiple regulatory T cell populations. In the present report we show that SEB induces a population of suppressor T cells which inhibits the generation of alloantigen-induced cytotoxic T cell activity. Using both negative- and positive-selection analysis, we found that this suppressor population is a CD4- CD8- CD5+ IL-2R+ T cell. This cell population inhibited both syngeneic and allogeneic cytotoxic T lymphocyte activity, but the cell population which inhibited allogeneic CTL activity was radiation sensitive. In addition, allogeneic SEB-primed cells appeared to develop cytolytic activity as a result of the additional stimulation in the mixed-lymphocyte reaction culture. The relationship of the SEB-primed CD4- CD8- CD5+ T cells to related regulatory T cell populations is discussed.

Depression of prothymosin alpha production in murine thymus correlates with staphylococcal enterotoxin-B-induced immunosuppression [corrected]

Prothymosin alpha [corrected] (ProT alpha) and thymosin beta 4 [corrected] (T beta 4) were isolated from murine thymus and characterized by microsequence analysis. Murine T beta 4 has an identical sequence to bovine T beta 4, whereas murine ProT alpha is highly homologous to rat Pro T alpha. Murine Pro T alpha differs from rat Pro T alpha at two positions, Glu100 and Asp108 of the rat sequence are substituted by aspartic and glutamic acid, respectively, in murine Pro T alpha. The amount of Pro T alpha in murine thymus was found to be reduced after in vivo treatment with staphylococcal enterotoxin B [corrected] (SEB), a superantigen which stimulates T cells bearing specific V beta receptors. Results from the anti-SRBC (sheep erythrocyte) plaque-forming cell assay showed that the antibody response of the spleen cells from these animals was also suppressed. On the other hand, the amount of T beta 4 was not changed significantly. Our studies suggest that the suppression of SEB on antibody response correlates with the depression of Pro T alpha production in the thymus.

Requirement for accessory cells in suppression of MOPC-315 IgA secretion by staphylococcal enterotoxin B-induced T-suppressor cells

Staphylococcal enterotoxin B (SEB) is a potent polyclonal activator of both human and murine T cells. We previously reported data which show that SEB-induced T cells suppress antibody secretion by various mouse plasmacytoma cell lines. This suppression of antibody secretion was found to be both idiotype and isotype nonspecific, and the suppressor cell bears the CD5-positive CD8-negative cell surface phenotype. The present studies demonstrate that accessory cells are required in the SEB-primed spleen cell (SEB-PSC) population in order for this population to mediate suppression. The suppressive activity of SEB-PSC is abrogated following accessory cell depletion by passage over Sephadex G-10 columns. B cell depletion using nylon-wool also abrogates suppression mediated by SEB-PSC. The addition of nonelicited adherent peritoneal exudate cells (PECs) restores suppressive activity to accessory cell-depleted SEB-PSC. The restoration of suppression by the PECs is not major histocompatibility complex restricted, since both syngeneic and allogeneic PECs can carry out this activity. In addition, it is not necessary for the accessory cells to be metabolically active in order to participate in the suppressive activity. This is based on results demonstrating that glutaraldehyde fixation, at levels reported to eliminate metabolic activity, does not affect the ability of PECs to restore suppression to Sephadex G-10-depleted SEB-PSC. The results are consistent with the well established requirement for accessory cells in the function of antigen-induced suppressor T cells.

[Influence of dexamethasone on electrical activities in cultured rat beating myocardial cells infected with Coxsackie B-2 virus]

The effects of dexamethasone (Dex) on electrical activities in cultured rat beating myocardial cells infected with 100 TCID-50 Coxsackie B-2 virus (CB2V) was evaluated by conventional intracellular microelectrode technique. The frequency began to increase, the beating % decreased, and multiform arrhythmias were shown in the infected group 24 h post-challenge. Meanwhile, the cytopathic effect (CPE) appeared rapidly from 1+ to 3+. In the infected and Dex-treated group, the beating % was higher and the arrhythmias and CPE were less than in the infected group at the same intervals. The numbers of non-beating cells increased parallel to the incubation time in the infected group. Decreases of maximal diastolic potential (MDP), maximal upstroke rate (Vmax), overshoot (OS) and action potential amplitude (APA), and abbreviation of action potential duration (APD50 and APD100) in infected and Dex-treated group were less than those in control group during 24-96 h post-challenge. Premature beats, tachycardia, bradycardia and fibrillation occurred in the early stages after infection. It is surmised that steroids can probably save the lives of patients with severe myocarditis if Dex was supplemented.

A mechanism for synergistic activation of a mammalian gene by GAL4 derivatives

In prokaryotes and eukaryotes many gene activators work synergistically. For example, two dimers of lambda repressor interact to promote binding of these proteins to DNA, a reaction that is crucial at the repressor concentrations found in lysogens. In this case one of the bound dimers activates transcription, evidently by touching RNA polymerase. In another example, the yeast transcriptional activator GAL4, which can stimulate transcription in many eukaryotes, binds to multiple sites on DNA to activate transcription synergistically; the presence of two such sites can elicit a level of transcription more than twice that found with a single site. In this paper we show that synergistic activation by each of several GAL4 derivatives involves a mechanism different from that illustrated by the lambda repressor: multiple activator molecules can work synergistically under conditions in which their binding sites on DNA are saturated. The accompanying paper shows that under similar conditions of activator excess, GAL4 derivatives work synergistically with a heterologous mammalian gene activator. These results support the idea that eukaryotic activators can cooperate not by directly interacting but by simultaneously touching some component(s) of the transcriptional machinery.

How different eukaryotic transcriptional activators can cooperate promiscuously

A striking characteristic of many different eukaryotic transcriptional activators is their ability to activate gene expression synergistically. Thus, for example, the rat glucocorticoid receptor and the yeast activator GAL4 cooperatively activate transcription of a mammalian gene bearing binding sites for each of the proteins: activation by both activators is greater than the sum of the effects of each working alone. It would seem unlikely that these two proteins from such different organisms directly interact; rather, the idea has been suggested that these and at least some other eukaryotic activators can work synergistically by simultaneously touching some part of the transcriptional machinery. An important prediction of this idea is that synergy between two such activators would be seen under conditions where each is present at concentrations sufficiently high to saturate its site on DNA. In this paper we use transcription in vitro to confirm that prediction using a derivative of the yeast activator GAL4 and the mammalian transcription factor ATF. The accompanying paper describes a similar conclusion comparing the effects of singly and multiply bound GAL4 molecules.

Effect of astragalus membranaceus on electric activities of cultured rat beating heart cells infected with Coxsackie B-2 virus

Astragalus membranaceus (AM) which has a protective effect on rat beating heart cells infected experimentally with Coxsackie B-2 virus was evaluated on the basis of changes in morphologic and electric activity of the cells. Rhythm, beating frequency, beating percentage, cardiac cellular damage and cytopathic effects (CPE) were monitored every 24 h after challenge; electric activities parameters were measured by conventional intracellular microelectrode technique. Significant protective effects were demonstrated when AM was given in the early period of infection. The results suggest that AM should be valuable in preventing and treating acute myocarditis caused by Coxsackie B virus.

A new approach to suppress bucking before extubation--lidocaine through modified endotracheal tube

The conventional endotracheal tube was modified with an epidural catheter adhered on the concave aspect of it. The opening of the catheter is at the proximal margin of the cuff. Local anesthetic can be injected into the trachea, then desensitize the tracheal mucosa nearby the cuff. Thirty-four female gynecological patients underwent abdominal total hysterectomy were studied and divided into three groups. In group 1, anesthesia was maintained without special management. In groups 2 and 3, 2 mL gentian violet stained 4% lidocaine solution was administered intratracheally by two different methods 60-120 minutes before the conclusion of the surgery. The peak cuff pressures generated by the awakening patients were 53.8 +/- 2.2 cm H2O (mean +/- SE) in group 1, 47.3 +/- 2.5 cmH2O (Group 2) and 36.4 +/- 1.6 cmH2O Group 3) respectively. Bucking before awakening was also evaluated clinically and showed 100%, 73% and 0% in each group. Intratracheal administration of lidocaine in dose of 2 mL 4% showed significant effect for the suppression of bucking during the recovery of general anesthesia in group 2 and 3 compared with the group 1. Lidocaine administered through the catheter of modified endotracheal tube also resulted in less increase in the peak cuff pressure and even no clinically observed bucking than direct administered through the endotracheal tube. Gag reflex was preserved in all patients and none had suffered from aspiration postoperatively.

Estimation of the length of nasopharyngeal airway in Chinese adults

Nasopharyngeal airway should be placed to reach the tongue base without contact with the epiglottis. The correct length of the nasopharyngeal airway in Chinese adults was estimated in seventy-three surgical patients under general anesthesia (30 males and 43 females, aged 18-82 yr). Measurements were performed with a soft, uncuffed, ID 6.0 mm endotracheal tube (Portex) introduced through the nasopharyngeal passage. The proper tip placement of the tube was evaluated under direct laryngoscopy. The Nostril-epiglottis distance (N-E distance) is 15.31 +/- 1.09 cm (mean +/- SD) for all cases, 16.03 +/- 1.04 cm for male cases and 14.97 +/- 0.95 cm for female cases. There are correlation between the N-E distance and the height (p less than 0.001, r = 0.41), and between the N-E distance and the N-A distance (The distance from nose tip to mandibular angle) (p less than 0.004, r = 0.324). Linear regression analysis relating the N-E distance to the height and the N-E distance to the N-A distance were also statistically significant (p less than 0.001 and p less than 0.01, respectively).

Characterization and genetic restriction of suppressor-effector cells induced by staphylococcal enterotoxin B

The capacity of the staphylococcal enterotoxins to stimulate all T cells bearing certain (but not all) TCR has generated a great deal of interest. This stimulation appears to involve specific binding of the toxin to class II Ags and subsequent stimulation via the TCR. Previous studies from this laboratory have demonstrated that staphylococcal enterotoxin B (SEB) induces multiple T suppressor cell populations that inhibit both primary and secondary plaque-forming cell responses. Efforts to characterize these suppressor cell populations have demonstrated that the suppressor population active early in the antibody response expresses the Lyt-1-2+ cell surface phenotype, whereas depletion analysis suggests that the population active late in an ongoing response bears the Lyt-1+2+ cell-surface markers. In the present study, enrichment for this late acting effector population with the use of sequential panning with anti-Lyt mAb reveals significant suppressive activity at both the initiation and effector phases of a 5-day Mishell-Dutton coculture. Additional experiments using I-J disparate strains of mice have demonstrated a genetic restriction at the "I-J" gene locus between the cells mediating SEB-induced suppression and their target. Depletion of SEB-primed splenocytes with anti-I-J mAb suggests that both the early and late effector cells bear I-J molecules on their surface. Taken together, these results show that SEB induces suppressor cell populations with properties similar to those exhibited by Ag-specific cell circuits.

Characterization and genetic restriction of suppressor-effector cells induced by staphylococcal enterotoxin B

The capacity of the staphylococcal enterotoxins to stimulate all T cells bearing certain (but not all) TCR has generated a great deal of interest. This stimulation appears to involve specific binding of the toxin to class II Ags and subsequent stimulation via the TCR. Previous studies from this laboratory have demonstrated that staphylococcal enterotoxin B (SEB) induces multiple T suppressor cell populations that inhibit both primary and secondary plaque-forming cell responses. Efforts to characterize these suppressor cell populations have demonstrated that the suppressor population active early in the antibody response expresses the Lyt-1-2+ cell surface phenotype, whereas depletion analysis suggests that the population active late in an ongoing response bears the Lyt-1+2+ cell-surface markers. In the present study, enrichment for this late acting effector population with the use of sequential panning with anti-Lyt mAb reveals significant suppressive activity at both the initiation and effector phases of a 5-day Mishell-Dutton coculture. Additional experiments using I-J disparate strains of mice have demonstrated a genetic restriction at the "I-J" gene locus between the cells mediating SEB-induced suppression and their target. Depletion of SEB-primed splenocytes with anti-I-J mAb suggests that both the early and late effector cells bear I-J molecules on their surface. Taken together, these results show that SEB induces suppressor cell populations with properties similar to those exhibited by Ag-specific cell circuits.

Similarities between prokaryotic and eukaryotic cyclic AMP-responsive promoter elements

Organisms as diverse as bacteria and man contain genes that show transcriptional induction when the intracellular concentration of cAMP is increased. This regulated transcriptional response is mediated through specific promoter elements located, in general, upstream from the transcription start site. In Escherichia coli the element responsible for cAMP-mediated transcriptional induction is the binding site for the cAMP-receptor protein (CAP). In mammalian cells the cAMP regulatory element is composed of one or more binding sites for various transcription factors. In many instances the cAMP regulatory element contains binding sites for a family of proteins referred to as ATF. Here we provide evidence that some prokaryotic and mammalian cAMP-response elements are functionally related. First, we show that mammalian ATF binds specifically to some E. coli CAP sites, and conversely E. coli CAP binds specifically to some mammalian ATF sites. Second, we demonstrate that an E. coli CAP binding site can confer cAMP-inducibility onto a mammalian gene when assayed in transfected mammalian cells.

Immunomodulatory activity of staphylococcal enterotoxin-B. The induction of an I-J-restricted suppressor factor

Staphylococcal enterotoxin-B (SEB), a common cause of food-borne intoxication, is a potent polyclonal T cell activator. Previous studies from this laboratory and others have shown that SEB has the capacity to nonspecifically inhibit antibody responses both in vivo and in vitro. We have shown that the inhibitory activity of SEB is mediated, in part, by the activation of a CD8+, CD4-, and CD5- suppressor cell population. The present studies show that the activity of the SEB-induced suppressor cell population is mediated by a soluble factor. This factor nonspecifically inhibits both primary and secondary in vitro antibody responses. Delayed addition analysis demonstrates that the factor must be present early in the ongoing antibody response to exhibit suppressive activity. Monoclonal anti-I-J antisera block the activity of the factor, and eluates (but not filtrates) collected from monoclonal anti-I-J immunoaffinity columns possess suppressive activity. Furthermore, the activity is restricted at the "I-J" gene locus, but is not restricted at the Igh locus. Finally, size-exclusion chromatographic analysis shows that the factor possesses an apparent Mr of 26 kDa. These studies suggest that SEB induces the production of a suppressive factor with properties similar to those exhibited by Ag-induced, and typically Ag-specific, suppressor factors.

Immunomodulatory activity of staphylococcal enterotoxin-B. The induction of an I-J-restricted suppressor factor

Staphylococcal enterotoxin-B (SEB), a common cause of food-borne intoxication, is a potent polyclonal T cell activator. Previous studies from this laboratory and others have shown that SEB has the capacity to nonspecifically inhibit antibody responses both in vivo and in vitro. We have shown that the inhibitory activity of SEB is mediated, in part, by the activation of a CD8+, CD4-, and CD5- suppressor cell population. The present studies show that the activity of the SEB-induced suppressor cell population is mediated by a soluble factor. This factor nonspecifically inhibits both primary and secondary in vitro antibody responses. Delayed addition analysis demonstrates that the factor must be present early in the ongoing antibody response to exhibit suppressive activity. Monoclonal anti-I-J antisera block the activity of the factor, and eluates (but not filtrates) collected from monoclonal anti-I-J immunoaffinity columns possess suppressive activity. Furthermore, the activity is restricted at the "I-J" gene locus, but is not restricted at the Igh locus. Finally, size-exclusion chromatographic analysis shows that the factor possesses an apparent Mr of 26 kDa. These studies suggest that SEB induces the production of a suppressive factor with properties similar to those exhibited by Ag-induced, and typically Ag-specific, suppressor factors.

Reliability of the Doppler pressure half-time method for assessing effects of percutaneous mitral balloon valvuloplasty

The mitral valve areas determined by Doppler pressure half-time and by cardiac catheterization with use of the Gorlin formula were compared in 18 adult patients who underwent percutaneous mitral balloon valvuloplasty. Doppler measurements and catheterization were performed simultaneously before, immediately after and 24 to 48 h after valvuloplasty. A high correlation between Doppler- and catheterization-derived mitral valve areas was found before mitral valvuloplasty (r = 0.81, Y = 0.88X + 0.1, SEE = 0.11 cm2) and 24 to 48 h after valvuloplasty (r = 0.84, Y = 0.70X + 0.67, SEE = 0.20 cm2). In contrast, the correlation immediately after valvuloplasty was only moderate (r = 0.72, Y = 0.43X + 1.1, SEE = 0.49 cm2). The Doppler-derived mitral valve area (2.41 +/- 0.61 cm2) immediately after valvuloplasty was significantly larger than the catheterization-derived area (2.08 +/- 0.39 cm2, p less than 0.05). In conclusion, the Doppler echocardiographic measurement performed with the pressure half-time method may lead to significant error immediately after mitral balloon valvuloplasty, but clinically accurate measurement can be obtained 24 to 48 h after valvuloplasty.

Identification and purification of a Saccharomyces cerevisiae protein with the DNA binding specificity of mammalian activating transcription factor

Activating transcription factor (ATF) is a mammalian transcriptional activator, which is involved in the expression of many viral E1a-inducible and cellular cAMP-inducible genes. Here we identify from the yeast Saccharomyces cerevisiae a previously uncharacterized protein whose DNA binding specificity is like mammalian ATF. We purify this protein (yATF) and show that it is a 66-kDa polypeptide. Finally, we demonstrate that a mammalian ATF site can function as an upstream activating sequence in S. cerevisiae. Taken together, our results suggest that yATF is a previously uncharacterized S. cerevisiae transcriptional activator.

Production and characterisation of monoclonal antibodies specific for staphylococcal enterotoxin B

We have generated monoclonal antibodies (MABs) to staphylococcal enterotoxin B (SEB) in BALB/c mice. Five out of 20 clones which produce anti-SEB MABs have been characterised. Among them, three produce IgG1/kappa, one produces IgM/lambda, and one apparently produces both IgG1/lambda and IgM/lambda MABs. The anti-SEB titres of ascites fluids range from 3200 to greater than 819200 by ELISA. All of the MABs analysed thus far neutralise the mitogenic response of BALB/c splenocytes to a suboptimal dose of SEB. Also, the induction of suppressor cells by SEB in vitro is reversed by pre-incubating SEB with these MABs. Limited digestion with chymotrypsin, trypsin or Staphylococcus aureus V8 protease yields peptide fragments which have been tested by Western-blot analysis. MABs 1FD7 and 2GD9 are specific for the carboxy-terminal end of SEB, and have a similar, but not identical, binding epitope. MABs 2DA3 and 2HA10 bind to intact SEB but not to cleaved products, and are probably specific for antigenic determinants altered by the cleavage or by the denaturing conditions of the electrophoresis, or by both.

Percutaneous mitral balloon dilatation by a new sequential single- and double-balloon technique

Percutaneous balloon valvotomy by means of a new sequential single- and and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dilatation procedure was initially performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two balloons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dilatation was successful in all patients; the mitral valve pressure gradient decreased from 19 +/ 6 to 5 +/ 2 mm Hg, the cardiac output increased from 4.0 +/ 0.5 to 5.2 +/ 0.6 L/min, and the MVA increased from 0.8 +/ 0.2 to 1.9 +/ 0.4 cm2 (p less than 0.01 each). The MVA after dilatation was relative to the effective balloon dilatation diameter selected (r = 0.57; p less 0.01). A small atrial septal defect was observed in 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced in 3 of 23 patients by the dilatation. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamics in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 +/ 18 mm of two balloons) is necessary for effective dilatation.

A common trans-acting factor is involved in transcriptional regulation of neurotransmitter genes by cyclic AMP

Activation of neurotransmitter receptors can regulate transcription in postsynaptic cells through the actions of second messengers. Trans-synaptic regulation of transcription appears to be an important mechanism controlling the synthesis of molecules involved in neuronal signaling, especially neuropeptides. Proenkephalin, vasoactive intestinal polypeptide, and somatostatin have been shown to be transcriptionally regulated by the second messenger, cyclic AMP (cAMP), as has the catecholamine synthesizing enzyme tryosine hydroxylase. cAMP-inducible elements have been mapped within these genes, and trans-acting factors which bind to several such elements have been identified. With the discovery that individual neurons generally contain multiple transmitters within their synaptic terminals, it has become important to understand in detail the mechanisms by which the synthesis of transmitters can be coregulated. Here we compare the structure and function of the proenkephalin cAMP-inducible enhancer with the mapped cAMP-inducible elements of the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and a putative cAMP-inducible element in the proto-oncogene c-fos. We have previously shown that the proenkephalin enhancer is composed of two different elements, ENKCRE-1 and ENKCRE-2. We show here that one of these, ENKCRE-2, is structurally similar to elements found within the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and binds a trans-acting factor that is competed for both in cotransfection experiments (in vivo) and in DNase I footprint assays (in vitro) by these other elements. The c-fos element has similar structural requirements to confer transcriptional induction by cAMP but competes less strongly. Protein purified by affinity chromatography with the ENKCRE-2 sequence binds to each of these elements. A second element within the proenkephalin cAMP-inducible enhancer, ENKCRE-1, binds a factor that is not competed for by these other genes and is therefore distinct. This analysis suggests a potential mechanism of transcriptional coregulation of the neuronally expressed genes investigated in this study and also demonstrates that multiple factors are involved in transcriptional activation by cAMP.

Transcription factor ATF interacts with the TATA factor to facilitate establishment of a preinitiation complex

The mammalian activator protein ATF stimulates transcription from the adenovirus E4 promoter by binding to multiple upstream promoter and enhancer elements. DNAase footprint analyses have revealed that there are cooperative interactions between ATF and TFIID (the mammalian TATA factor) when both are bound simultaneously to the promoter and that these interactions in turn facilitate promoter recognition by RNA polymerase II and the general initiation factors TFIIB and TFIIE. However, the complex of TFIID and the other general factors is stable following oligonucleotide-mediated dissociation of ATF from the complete preinitiation complex. These results indicate that TFIID is a direct target for ATF, that these interactions facilitate assembly of a complete preinitiation complex, and that the role of ATF might be transient.

GAL4 derivatives function alone and synergistically with mammalian activators in vitro

We show that derivatives of the yeast transcriptional activator GAL4, synthesized in and purified from E. coli, stimulate transcription of a mammalian gene (the adenovirus E4 gene) in a HeLa cell nuclear extract. Stimulation depended upon GAL4 binding sites inserted in the template. When the GAL4 sites were placed immediately upstream of the E4 TATA box, GAL4 stimulated efficiently. When the GAL4 sites were further upstream from TATA, however, efficient stimulation by GAL4 required, in addition, a site for a mammalian transcriptional activator immediately upstream of TATA. Under these conditions, the GAL4 derivatives functioned synergistically with the proximally bound activator. Previous experiments have defined two "activating regions" in GAL4, and our current experiments define a third, whose function is observed in vitro but not in vivo.

Induction of suppressor cells by staphylococcal enterotoxin B: identification of a suppressor cell circuit in the generation of suppressor-effector cells

We have shown previously that staphylococcal enterotoxin B (SEB) has the capacity to non-specifically inhibit antibody responses in vitro through the induction of a suppressor cell population. In the present studies, an analysis of the cellular dynamics has shown that the generation of Lyt-1-2+ suppressor-effector cells is dependent on the initial activation by SEB of an Lyt-1+2- suppressor-inducer population. Co-culture experiments carried out in vitro suggest that the induction of the suppressor-effector population requires at least two signals: one signal is provided by the suppressor-inducer population, and the second signal is provided by SEB. Studies also show that the in vitro antibody response is suppressed when the suppressor cells are added as late as Day 4 of a 5-day culture. While the suppressor cell population activated early in the antibody response is Lyt-1-2+, depletion studies suggest that the population that acts late in an ongoing response bears the Lyt-1+2+ surface phenotype. The results demonstrate that at least three distinct SEB-induced T-cell populations are capable of participating in the suppression of the antibody response. The relationship between the generation of non-specific suppressor cells and the activation of antigen-specific cell circuits is discussed.