Oncogenic stimulation recruits cyclin-dependent kinase in the cell cycle start in rat fibroblast

The rat fibroblast NRK cells are transformed reversibly by a combination of growth factors. When stimulated with serum, NRK cells rely on cyclin-dependent kinase 4 (Cdk4) for their S phase entry. However, when stimulated with serum containing oncogenic growth factors, they come to rely on either Cdk4 or Cdk6, and their S phase entry cannot be blocked unless both Cdk4 and Cdk6 are immunodepleted. Such change of dependence does not occur in the NRK cell mutants defective in an oncogenic signal pathway and, therefore, deficient in anchorage-independent cell cycle start ability, correlating Cdk6 dependence with this remarkable, cancer-associated phenotype. However, both Cdk4 and Cdk6 are activated upon serum stimulation, and neither the amounts of Cdk6, Cdk4, cyclin D1, and cyclin-dependent kinase inhibitors nor the activities or subcellular localization of Cdk6 and Cdk4 are significantly influenced by oncogenic stimulation. Thus, oncogenic stimulation invokes Cdk6 to participate in a critical step of the cell cycle start in a rat fibroblast, but by a mechanism seemingly unrelated to the regulation of the kinase. Given that many hematopoietic cells employ predominantly Cdk6 for the cell cycle start and perform anchorage-independent growth by nature, our results raise the possibility that the oncogenic stimulation-induced anchorage-independent cell cycle start of NRK is elicited by a mechanism similar to the one used for hematopoietic cell proliferation.

A double-strand break repair component is essential for S phase completion in fission yeast cell cycling

Fission yeast rad22(+), a homologue of budding yeast RAD52, encodes a double-strand break repair component, which is dispensable for proliferation. We, however, have recently obtained a cell division cycle mutant with a temperature-sensitive allele of rad22(+), designated rad22-H6, which resulted from a point mutation in the conserved coding sequence leading to one amino acid alteration. We have subsequently isolated rad22(+) and its novel homologue rti1(+) as multicopy suppressors of this mutant. rti1(+) suppresses all the defects of cells lacking rad22(+). Mating type switch-inactive heterothallic cells lacking either rad22(+) or rti1(+) are viable, but those lacking both genes are inviable and arrest proliferation with a cell division cycle phenotype. At the nonpermissive temperature, a synchronous culture of rad22-H6 cells performs DNA synthesis without delay and arrests with chromosomes seemingly intact and replication completed and with a high level of tyrosine-phosphorylated Cdc2. However, rad22-H6 cells show a typical S phase arrest phenotype if combined with the rad1-1 checkpoint mutation. rad22(+) genetically interacts with rad11(+), which encodes the large subunit of replication protein A. Deletion of rad22(+)/rti1(+) or the presence of rad22-H6 mutation decreases the restriction temperature of rad11-A1 cells by 4-6 degrees C and leads to cell cycle arrest with chromosomes incompletely replicated. Thus, in fission yeast a double-strand break repair component is required for a certain step of chromosome replication unlinked to repair, partly via interacting with replication protein A.

Clinical usefulness of TSAb assay with high polyethylene glycol concentrations

We previously demonstrated the stimulatory effect of polyethylene glycol (PEG) on thyroid-stimulating antibody (TSAb)-IgG-stimulated cAMP production (thyroid stimulating (TS) index) in porcine thyroid cell (PTC) assay. In the present study the clinical usefulness of the practical method using high PEG concentrations was examined. TS activity using PEG 22.5% precipitated fraction (PF) was significantly higher compared to standard TSAb activity using 12.5% PF from TSAb-positive serum, but the maximum TS activity was observed with PEG 12.5% PF + 4% PEG or PEG 22.5% PF + 2% PEG. In all cases of untreated Graves' patients, TSAb activity determined by PEG 22.5% PF was higher compared to standard TSAb activity using PEG 12. 5% PF from test serum, but the highest TSAb activity was observed by PEG 12.5% PF + 4% PEG without increased cAMP production to normal serum. TSAb was positive in 85% (40/47), 98% (46/47) and 100% (47/47) of untreated Graves' patients by the method of PEG 12.5% PF, PEG 22.5% PF and PEG 12.5% + 4% PEG, respectively. Increased TSAb activity by PEG 12.5% PF + 4% PEG method was also observed even if the standard TSAb activity using PEG 12.5% PF method was negative in the euthyroid states of Graves' patients during antithyroid drug therapy. The stimulatory effect of PEG on TS activity was not found in other thyroidal diseases [thyroiditis chronica (with high serum TSH), thyroid stimulation-blocking antibody (TSBAb)-positive sera (with low serum TSH), adenomatous goiter, subacute thyroiditis, and thyroid cancer]. The stimulatory effect of 5% PEG on TS activity produced directly by small amounts of Graves' serum (50 microl) was also found, although the sensitivity was lower than with PEG-precipitated IgG from 0.2 ml serum. The clinical usefulness of the sensitive TSAb assay using PEG-precipitated IgG or direct serum assay in the presence of high PEG concentrations was demonstrated.

Basic study on gene therapy of human malignant glioma by use of the cationic multilamellar liposome-entrapped human interferon beta gene

For gene therapy of human malignant glioma, we adopted positively charged multilamellar liposomes entrapping the human interferon beta (hIFN-beta) gene. One week after the transplantation of human malignant glioma U251-SP cells to produce glioma in nude mouse brain, the liposomes entrapping the gene (500 ng of DNA per 25 nmol of lipids per 2 microl) were injected into the same site of the cell transplantation once every second day for a total of five injections; and by this means the tumor completely disappeared. To confirm the antiproliferative effect of hIFN-beta, we performed an in vitro study using a plasmid containing a secretion signal sequence-deleted hIFN-beta gene and one containing the hIFN-beta gene inserted in reverse. In both cases, there was no hIFN-beta release into the medium and no growth inhibition effect. On addition of anti-hIFN-beta antibody to the medium, the growth inhibition effect was abolished. As this cell line expresses IFN-alpha/beta receptor, the hIFN-beta produced in the transfected cells could be released and acted in a paracrine manner. For 120 days the body weight change of normal mice treated by the same procedure as used in the curing experiment was not significant among the groups injected with empty liposomes, plasmid only, and liposomes entrapping the gene. In all of these three groups, death, abnormal behavior, and significant histological changes were not observed.

Disruption of cholecystokinin (CCK)-B receptor gene did not modify bile or pancreatic secretion or pancreatic growth: a study in CCK-B receptor gene knockout mice

Pancreatic exocrine function and bile secretion were examined in cholecystokinin (CCK)-B receptor gene-targeted mice and compared among different genotypes [i.e., CCK-B receptor gene: (+/+), wild-type; (+/-), heterozygous; and (-/-), homozygous deficient]. The histology and protein concentrations in the pancreas also were examined. Amylase release from the dispersed acini was examined in vitro by using the various doses of CCK-8, carbachol, and secretin. In vivo, the bile and pancreatic juice were collected, and the concentrations of amylase and bile acid were measured in anesthetized mice. The responses to CCK (100 pmol/kg) or acetyl-beta-methylcholine (500 nmol/kg) were examined. In vitro studies showed that the maximal effective concentrations of CCK-8 (10(-l0) M), carbachol (10(-5) M), and secretin (5 x 10(-7) M) were comparable for all genotypes. Fluid, amylase, and bile acid outputs in vivo also were comparable for all genotypes. Pancreatic wet weight and protein concentrations were not significantly different, and no abnormal findings were observed on histologic examination in any genotype. These results indicated that the CCK-B receptor has no role in pancreatic growth, exocrine secretion, or bile secretion in adult mice.

Clinical significance of a sensitive assay for thyroid-stimulating antibodies in Graves' disease using polyethylene glycol at high concentrations and porcine thyroid cells

The Inui and Ochi group recently reported that cAMP production by porcine thyroid cells (PTC) was augmented more by polyethylene glycol (PEG) 22.5% precipitated fractions from almost all Graves' sera than those of PEG 12.5%. In the present study, thyroid stimulating immunoglobulin (TSI) activity was determined with PTC and prepared crude Ig fractions precipitated by two different concentrations of PEG (final concentrations 13.5% and 22.5%) from sera obtained from 117 Graves' patients. The activity of TSI determined by the PEG 13.5% assay and activity determined by the PEG 22.5% assay were designated as thyroid-stimulating antibody (TSAb) and sTSAb, respectively. At first we studied 55 TSAb-positive patients with untreated hyperthyroid Graves' disease and classified them according to the TSAb activity-below 500% (group 1) and above 500% (group 2). The positive stimulatory effect, arbitrarily defined as the ratio of sTSAb to TSAb, being more than 1.2, was observed in 85% of patients, and group 1 had a significantly (P<0.025) greater stimulatory effect (34/35, 97.1%) than group 2 (13/20, 65%). Subsequently, in 29 TSAb-negative patients, sTSAb was measured and detected in 26 (89.7%). Finally, sTSAb, TSAb and TBII were compared between patients presenting with recurrent Graves' disease and those with silent thyroiditis after withdrawal of antithyroid drug treatment for Graves' disease. sTSAb was detected in all 14 relapsed patients, but none of the 9 patients with silent thyroiditis had detectable sTSAb. In contrast, TSAb and TBII activities were found in only 7 (50.0%) of the 14 relapsed cases. The present paper demonstrated that the assay with a higher PEG concentration was found to be sensitive, specific and useful for the diagnosis and follow-up of Graves' disease after drug withdrawal, although the underlying mechanism remains unclear.

Effects of nitrous oxide on haemodynamic and electroencephalographic responses induced by tetanic electrical stimulation during propofol anaesthesia

We studied the effect of nitrous oxide on haemodynamic and electroencephalographic responses caused by noxious stimulation during propofol anaesthesia. Thirty-four patients (ASA I-II) were anaesthetised with propofol 3 mg x kg(-1) and were randomly allocated to receive either 60% nitrous oxide in oxygen or 40% oxygen in air. Anaesthesia was maintained using propofol infusion of 10 mg x kg(-1) x h(-1) for the first 10 min, 8 mg x kg(-1) x h(-1) for the next 10 min and 6 mg x kg(-1) x h(-1) thereafter. Thirty minutes after the induction of anaesthesia, tetanic electrical stimulation (80 mA, 100 Hz) was applied to the ulnar nerve. Tetanic stimulation significantly increased blood pressure and heart rate in both groups (p < 0.005 or less), but did not induce any arousal pattern on the electroencephalograph. Nitrous oxide significantly attenuated the tetanic stimulation-induced increase in blood pressure (p < 0.05 or less), but not the heart rate.

Polyethylene glycol augments thyroid cAMP responses by fragments from protease-digested TSAb or TSBAb-IgG

In the previous reports, we have demonstrated (1) that polyethylene glycol (PEG)(5%) augmented TSAb (thyroid stimulating antibody)-stimulated cAMP responses of porcine thyroid cells, and (2) that fragments from papain-digested TSBAb (thyroid stimulation blocking antibody) could stimulate thyroid cAMP synthesis. Thus, we studied the effect of 5% PEG on cAMP responses stimulated by the protease-digested TSAb- or TSBAb-fragments. Stimulatory effect of 5% PEG on cAMP production by Fab fragment (Mr 50 KDa) and the retarded fraction (Mr 20 KDa) from the gel-filtration on Sephadex G-100 using papain-digested TSAb-IgG unbound to Protein A-Sepharose was observed. Similar stimulatory effect of 5% PEG on the second fraction (Fc with trace amounts of Fab) in the gel-filtration on Sephadex G-100 using papain digested TSAb-IgG bound to Protein A-Sepharose was observed. Stimulatory effect of PEG on the second fraction was derived from Fab fragment. PEG (5%) also showed stimulatory effect on cAMP production by F(ab')2 fragment (Mr 100 KDa) from the gel-filtration on Sephadex G-100 using pepsin-digested TSAb-IgG unbound to Protein A-Sepharose. PEG (5%) augmented cAMP responses by both Fab and the retarded fractions from the gel-filtration using papain-digested TSBAb-IgG unbound to Protein A when these fractions could stimulate cAMP synthesis. In conclusion, PEG (5%) augments cAMP responses stimulated by F(ab')2, Fab and the smaller molecular components (Mr 20 KDa) separated from protease-digested TSAb-IgG. PEG also augments cAMP responses stimulated by Fab and the smaller molecular components with thyroid stimulating activity separated from papain-digested TSBAb-IgG.

Augmentation of thyroid-stimulating antibody-stimulated cyclic adenosine monophosphate response by polyethylene glycol, polyvinyl alcohol, and dextran; highly sensitive porcine thyroid cell thyroid-stimulating antibody assay

Previously, we reported that 5% polyethylene glycol (PEG) (6000) augmented thyroid-stimulating antibody (TSAb)-stimulated cyclic adenosine monophosphate (cAMP) production in porcine thyroid cell (PTC) assay. This augmentation by PEG was specific to TSAb-stimulation. In this study we examined the effects of nonionic hydrophilic polymers such as PEG, polyvinyl alcohol (PVA), and dextran (DEX) on TSAb-stimulated cAMP production. We demonstrated that graded doses of PEG, PVA, and DEX augmented TSAb-stimulated cAMP productions; the prominent augmentations were observed with 5% PEG (20,000), 5% PEG (6000), 6% PEG (4000), 10% PVA, 14% DEX T-250, and 14% DEX T-70. PVA did not augment thyrotropin (TSH)-stimulated cAMP synthesis. Five percent PEG (20,000), 14% DEX T-250, and 14% DEX T-70 augmented TSH-stimulated cAMP synthesis very slightly. PEG, PVA, and DEX had no effects on the cAMP synthesis stimulated by GTPgammaS, forskolin, or pituitary adenylate cyclase activating polypeptide (PACAP), which stimulated adenylate cyclase. We also demonstrated that PEG, PVA, and DEX augmented the cAMP responses stimulated by small amounts (50 microL) of sera from Graves' patients; small amounts (50 microL) of sera could be used instead of purified immunoglobulin G (IgG). This may simplify the TSAb assay. We developed a highly sensitive simplified TSAb assay. PEG weakly augmented TSAb binding to isolated TSH receptor (thyrotropin-binding inhibitor immunoglobulin [TBII] increased slightly). The mechanisms of the augmentations of TSAb-stimulated cAMP productions by PEG, PVA, and DEX is not simply explained by increased binding of TSAb to the receptors. Some factors that enhance TSAb action at the receptor site are suggested.

Mechanism of the augmentative effect of high polyethylene glycol (PEG) concentrations on the thyroid stimulating activity in TSAb-IgG using a porcine thyroid cell assay

We previously demonstrated that high polyethylene glycol (PEG) concentrations (5% PEG) significantly augmented cAMP production in response to TSAb-IgG using the porcine thyroid cell (PTC) assay. The mechanism of the stimulatory effect of 5% PEG on cAMP production was examined by a two-step incubation with PTC. TSAb-IgG was preincubated with or without addition of 5% PEG in the PTC assay for 2.5 hr (1st incubation) and separated PTC was re-incubated with fresh Hank's buffer for 5 hr (2nd incubation). cAMP production in the 1st incubation medium by co-incubation of TSAb-IgG and 5% PEG for 2.5 hr was significantly increased (3.3-fold) compared to that without 5% PEG. When the cAMP content in PTC and the incubation medium were compared in the same volume of incubation medium after co-incubation of TSAb-IgG and 5% PEG for 2.5 hr, cAMP contents in PTC were about 7-fold higher than that in the incubation medium, and this ratio did not change in the incubation medium of TSAb-IgG without 5% PEG. Similar increases in cAMP contents in PTC (6.6-fold) compared to the incubation medium were also observed with bTSH, although there was no augmentative effect of 5% PEG on cAMP production by bTSH in either the incubation medium or PTC. When PTC, which had been preincubated with normal-IgG and 5% PEG in the 1st incubation, was re-incubated with TSAb-IgG in the 2nd incubation medium, cAMP production by TSAb-IgG was not stimulated by 5% PEG. The augmentative effect of 5% PEG on cAMP production by TSAb-IgG was observed whenever 5% PEG and TSAb-IgG were co-incubated in either the 1st or 2nd incubation. However, no stimulatory effect of 5% PEG on bTSH was observed. These results suggested the stimulatory effect of 5% PEG on TSAb-IgG-stimulated cAMP production may be due to the increase of binding or incorporation of TSAb-IgG into the membranes of PTC compared to TSH.

Lack of tactile pain (allodynia) in lipocalin-type prostaglandin D synthase-deficient mice

Prostaglandin (PG) D2 is the most abundant prostanoid produced in the central nervous system of mammals and has been implicated in the modulation of neural functions such as sleep induction, nociception, regulation of body temperature, and odor responses. We generated gene-knockout mice for lipocalin-type PGD2 synthase (L-PGDS) and found that the intrathecal administration of PGE2, an endogenous pain-producing substance, failed to elicit allodynia (touch-evoked pain), which is one typical phenomenon of neuropathic pain, whereas it evoked thermal hyperalgesia, in L-PGDS-/- mice. We also found that the allodynic response induced by the gamma-aminobutyric acid (GABA)A receptor antagonist bicuculline was selectively abolished in the L-PGDS-/- mice, among excitatory and inhibitory agents that induced allodynia in wild-type mice. Interestingly, simultaneous injection of a femtogram amount of PGD2 with PGE2 or bicuculline induced allodynia in L-PGDS-/- mice to the same extent as in wild-type mice. The PGE2- or bicuculline-evoked allodynia in wild-type and in PGD2-supplemented L-PGDS-/- mice was blocked by a PGD2 receptor antagonist given in a femtogram amount. These results reveal that endogenous PGD2 is essential for both PGE2- and bicuculline-induced allodynia.

Modulation of the soleus H reflex with different velocities of passive movement of the arm

Modulation of the gain of the soleus H reflex pathway produced by passive movement of the elbow joint was investigated and compared to that produced by passively maintained displacement of the elbow joint position. Little modulation of the gain of the soleus H reflex pathway was observed during passive displacement of the elbow joint position. In contrast, passive movement of the elbow joint facilitated the gain of the soleus H reflex amplitude and the degree of modulation was large as the velocity increased. The degree of the facilitatory effect upon passive movement of the upper extremity ipsilateral to the leg under test was larger than that obtained upon passive movement of the upper extremity contralateral to the leg under test. The modulation may be caused by discharge at the primary endings of the spindles in the upper extremity which is likely to excite propriospinal interneurons connecting to motor neurons of the lower extremity.

Propofol inhibits ketamine-induced c-fos expression in the rat posterior cingulate cortex

Ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, has psychotomimetic activity. NMDA receptor antagonists cause morphological damage in the posterior cingulate cortex, which may be the brain region responsible for their psychotomimetic effects. Benzodiazepines are effective in preventing these effects through gamma-aminobutyric acid A (GABA(A)) receptor activation. We investigated the effect of propofol, which has both GABAA receptor-activating and NMDA receptor-suppressing activity, on ketamine-induced c-fos expression in the rat posterior cingulate cortex. Propofol or vehicle was continuously infused IV. Fifteen minutes later, 100 mg/kg ketamine or isotonic sodium chloride solution was injected intraperitoneally. Two hours later, brain sections were prepared, and c-fos expression was detected using immunohistochemical methods. Propofol significantly inhibited ketamine-induced c-fos expression in the posterior cingulate cortex. Propofol itself did not induce c-fos expression in this brain region. We conclude that propofol may be able to inhibit ketamine-induced psychotomimetic activity and neuronal damage.

IMPLICATIONS

In the present study, we demonstrated that the clinically relevant dose of propofol significantly inhibited ketamine-induced c-fos expression in the rat posterior cingulate cortex. This finding implies that propofol may inhibit ketamine-induced psychotomimetic activity and neuronal damage.

The effects of the lateral position on cardiopulmonary function during laparoscopic urological surgery

Laparoscopic urological surgery is usually performed transperitoneally with retroperitoneal insufflation of carbon dioxide (CO2) in the lateral position. We studied whether a difference in the side of lateral position affected hemodynamic and pulmonary functions during pneumoperitoneum. Fifteen patients (eight in the right and seven in the left lateral position) undergoing elective laparoscopic urological surgery were studied under general anesthesia. Hemodynamic variables and blood gas data were recorded. Before insufflation, mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) in the right lateral position were higher than those in the left lateral position. Pneumoperitoneum increased MAP, MPAP, CVP, PCWP, and cardiac index but decreased systemic vascular resistance in the right lateral position. Similar changes occurred during pneumoperitoneum in the left lateral position, but the changes were less than those in the right lateral position. The respiratory index (PaO2/PAO2), intrapulmonary shunt, and SpO2 did not change during pneumoperitoneum in either lateral position. Changing the side of the lateral position affected hemodynamic function but did not affect pulmonary oxygenation during pneumoperitoneum.

IMPLICATIONS

The right and left lateral positions produced different hemodynamic changes during laparoscopic urological surgery. The increases in preload and cardiac index and the decrease in systemic vascular resistance were greater in the right than in the left lateral position. Respiratory changes were not affected differently between the right and left lateral positions.

Afterdischarges following F waves observed in a patient with tetanus

We report a case of non-fluminent and mildly affected tetanus patient who showed afterdischarges following F waves in the affected extremity. The afterdischarges occurred following F waves and showed different configuration respond to each stimuli. Diazepam was also effective for spasms of our patient. This finding disappeared after treatment and showed a good correlation to clinical symptoms. These observations suggest that afterdischarges following F waves are induced by tetanus toxin which puts most of the motor neuron pool in a hyperactive state through its own action to the motor nerve including the spinal motor neuron.

Case report: Steatonecrosis in the upper abdomen following transcatheter arterial embolization for hepatocellular carcinoma

A 66-year-old female with liver cirrhosis was treated by transcatheter arterial embolization (TAE) for a small hepatocellular carcinoma. She developed steatonecrosis with tenderness which occurred in the upper abdomen after TAE. The hepatic falciform artery from the middle hepatic artery was detected by arteriography. Necrosis in the upper abdomen was considered to be due to ischaemic changes caused by micromaterials for embolization of this artery, injuries of hepatic arterial endothelia slowly caused by carcinostatics, and chemotoxicity. It was considered that such complication as observed in this patient should be taken into consideration when performing TAE.

Increase of thyroid stimulating activity in Graves' immunoglobulin-G by high polyethylene glycol concentrations using porcine thyroid cell assay

Cyclic adenosine monophosphate (cAMP) production during a 5-hour incubation using porcine thyroid cells (PTC) was stimulated significantly more by polyethylene glycol (PEG) 22.5% precipitated fractions (ppt frs) than by PEG 12.5% ppt frs from almost all Graves' sera. However, the thyrotropin (TSH) binding inhibition (TBI) activities of the PEG 12.5% and 22.5% ppt frs using porcine thyroid membranes were similar, and did not change in the 5-hour incubation. When the PEG 12.5% ppt fr from Graves' serum and the PEG 22.5% ppt fr from normal human serum (NHS) were coincubated, cAMP production was also stimulated as much as by the PEG 22.5% ppt fr from Graves' serum. When purified thyroid stimulating antibody (TSAb)-immunoglobulin G (IgG) and the PEG 22.5% ppt fr from NHS were coincubated, increased cAMP production was also observed, whereas bovine thyrotropin (bTSH) did not produce this effect. When purified TSAb-IgG and PEG solutions were coincubated, maximum increases in cAMP production (approximately 10-fold) with 5% PEG were found, whereas no increase was observed using bTSH. The stimulatory effect of high PEG concentrations on thyroid stimulating activity was observed by TSAb-IgG in salt-free or salt-containing medium (<0.15 mol/L NaCl concentration) but not by either TSAb-IgG conjugated to protein A-sepharose 4B or the inactivated TSAb-IgG by the treatment of 70 degrees C for 10 minutes. No stimulatory action by PEG was found with the thyroid stimulating substances such as GTPgammaS, forskolin, or pituitary adenylate-cyclase activating polypeptide (PACAP). The increased thyroid stimulating activity of Graves (IgG) at high PEG concentrations suggests the existence of some factors influencing the ability of TSAb to stimulate thyroid cells, although the exact mechanism remains to be clarified.

High-performance liquid chromatographic separation of microcystins derivatized with a highly fluorescent dienophile

Microcystins are potent hepatotoxins produced by cyanobacteria, and are also tumor promoters as well as potent inhibitors of the catalytic subunits of protein phosphatases 1 and 2A. In order to establish a physicochemical method for individual detection and determination of trace amounts of microcystins, we developed a derivatization method for fluorescence (FL) and chemiluminescence (CL) detection, in which a highly fluorescent dienophile, DMEQ-TAD (4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl) ethyl]-1,2,4-triazoline-3,5-dione), was used as the labeling reagent. DMEQ-TAD reacted smoothly with the conjugated diene of the Adda moiety to give 2 stereoisomers of the adducts. As a result of the extensive experiments, the following reaction conditions were optimized for the labeling: sample amount, 10 micrograms; reaction solvent, DMF:acetonitrile (1:1); reaction time, 15 minutes; reaction temperature, 70 degrees C; amount of DMEQ-TAD used relative to that of microcystin, 80 equivalent. The resulting 6 adducts from microcystins-LR, -YR, and -RR can be separated from one another using the following reversed phase HPLC conditions in combination with a clean-up using ODS silica gel: column, Cosmosil 5C18-AR (150 x 4.6 I.D. mm); mobile phase, methanol:0.05M phosphate buffer (pH 3) (1:1); flow rate, 1.0 ml/min; detection, FL lambda ex 370 nm, lambda em 440 nm. The detection limits of the DMEQ-TAD derivatives were estimated to be 100 and 500 pg for LR, and 65 and 2,500 pg for RR using FL and CL detections, respectively; and the detection behavior was different from that of the Dns-Cys derivatives, which were more sensitive to CL than FL.

Neurotoxicodynamics of the interaction between ciprofloxacin and foscarnet in mice

The potential for convulsions induced by the coadministration of ciprofloxacin (CPFX) and foscarnet (PFA) may be due not to a change in the distribution of CPFX to the brain but to a potential CPFX-induced inhibition of gamma-aminobutyric acid (GABA)-GABA(A) receptor binding in the presence of PFA.

Demonstration of fragments with thyroid stimulating activity from thyroid stimulation blocking antibodies-IgG molecules by papain digestion

OBJECTIVES

Thyroid stimulation blocking antibodies (TSBAb) inhibit TSH action and may have a role in the pathogenesis of hypothyroidism. In order to study the relationship between blocking and stimulating activities we have examined the biologically active fragments in TSBAb-IgG molecules after papain digestion.

DESIGN

Both thyroid stimulating (TS) activity (cAMP production in thyroid cells) and TSH binding inhibitory (TBI) activity (determined by TSH receptor assay) in sera from patients with primary hypothyroidism were examined after digestion with papain-Sepharose in the presence of cysteine. The digested IgG was separated into unbound (UF) and bound (BF) fractions on a Protein A-Sepharose column. Each fraction was then gel-filtrated on a Sephadex G-100 column.

RESULTS

TS activity was found within one hour after hydrolysis in 5 out of 7 antibodies, then gradually decreased after more prolonged incubation. Both TS and TBI activities in the UF and the BF from Protein A were found in Feb (Mr 50 kD) and the second protein peak (Fc with trace amounts of Fab), respectively. The biological activity in the second protein peak was suggested as being derived from Fab fraction, because the activity bound to the anti-F(ab')2 column. However, the first peak (undigested IgG) in the BF had neither TS nor TSB activity. The TS activity in the retarded fraction (less than Mr 20 kD) in the UF gradually increased with prolonged digestion.

CONCLUSIONS

The conversion of Thyroid stimulation blocking antibodies activity to thyroid stimulating activity by papain digestion suggests that the inherent thyroid stimulating activity located in the Fab portion of the IgG molecule is unmasked by papain cleavage. We also suggest that the thyroid stimulating activity in the retarded fraction in the unbound fraction may be released from hydrolysis of the Fab portion of the IgG molecule.

Calmodulin purified from human and porcine thyroids inhibits thyrotropin binding to porcine thyroid cells

A thyrotropin (TSH) binding inhibiting protein (TBIP) that inhibits TSH binding to the TSH receptor, as determined by the TSH receptor assay, was purified from human and porcine thyroid. The soluble fraction (100,000 x g supernatant of Graves' thyroid homogenate) was precipitated with ammonium sulfate between 1.75 to 2.5 mol/L. TBIP was eluted by 0.5 mol/L sodium chloride (NaCl) containing 20 mmol/L Tris buffer, pH 7.5 from a Q-sepharose column. The unbound fraction from concanavalin A (Con A) and blue-sepharose was gel-filtered using sephadex G-100, and finally purified by Resource Q column chromatography. Purified TBIP was confirmed as a single protein band of 17 kDa. The TBI activity in the purified TBIP was significantly decreased by either etnylene glycol tetraacetate (EGTA) (1 mmol/L) or antibody to calmodulin (CaM) in the TSH receptor assay. The TBIP was confirmed immunologically as CaM by the Ouchterlony method using antibody for CaM. These findings demonstrated that the TBIP purified from human and porcine thyroids was, in fact, CaM. We examined the effects of TBIP purified from human thyroid on bovine TSH (bTSH) or thyroid stimulating antibody (TSAb)-stimulated cyclic adenosine monophosphate (cAMP) production in porcine thyroid cells (PTC). TBIP itself did not increase basal levels of cAMP production, but inhibited bTSH (100 mU/L)-stimulated cAMP production. However, TBIP did not inhibit cAMP production stimulated by TSAb-IgG and various thyroid stimulators (GTPgammaS, forskolin and pituitary adenylate cyclase-activating polypeptide [PACAP, 27 and 38 amino acids]). Authentic CaM purified from bovine brain behaved in a manner similar to that of TBIP. These data showed that CaM differentially affects thyroid stimulation by TSH and TSAb in intact thyroid cell experiments.

Enzyme-linked immunosorbent assay using F(ab')2 fragment for the detection of human pulmonary surfactant protein D in sera

We developed an enzyme-linked immunosorbent assay (ELISA) for detection of SP-D in serum using recombinant SP-D as a standard and horseradish peroxidase conjugated F(ab')2 fragment of mouse monoclonal antibody IgG to avoid the interaction of serum factors including rheumatoid factor. The use of F(ab')2 fragment dramatically decreased the value of serum SP-D concentration in rheumatoid arthritis patients without pulmonary complication to the close level of healthy volunteer. In contrast, the patients with collagen disease having interstitial pulmonary pneumonia exhibited consistently elevated levels of serum SP-D. The use of new ELISA with recombinant SP-D and F(ab')2 fragment of anti-SP-D monoclonal antibody gives a greater advantage for the accurate detection of SP-D in sera from patients with idiopathic pulmonary fibrosis, interstitial pneumonia with collagen disease and pulmonary alveolar proteinosis without interference of rheumatoid factor.

A zinc finger protein required for stationary phase viability in fission yeast

Yeast cells exit the cell cycle and enter a metabolically inert stationary phase when starved for nutrients essential for normal proliferation. We have cloned a novel gene named rsv1+ (required for stationary phase viability) that is essential for fission yeast cell viability in a stationary phase induced by glucose starvation. rsv1+ encodes a 47 kDa protein with two zinc finger motifs that are partially homologous with Aspergillus nidulans CreA, Saccharomyces cerevisiae Mig1 and mammalian EGR-1/NGFI-A. Cells deleted for rsv1+ are unable to survive glucose starvation. Transcription of rsv1+ is negatively regulated by the cAMP pathway and induced by glucose starvation. Cells with the constitutively activated cAMP pathway are known to lose viability when grown to confluence or when starved for glucose. These cells are poor in rsv1+ induction and their viability loss is largely suppressed by ectopic expression of rsv1+. Thus, poor induction of rsv1+ is at least partially responsible for the viability loss. Analysis also showed that cells need to receive starvation signals before entry into the stationary phase in order to maintain viability in a glucose-poor environment.

Thyroid-stimulating antibody and TSH-binding inhibitor immunoglobulin in 277 Graves' patients and in 686 normal subjects

TSH receptor antibodies (TRAb) are believed to cause hyperthyroidism of Graves' disease. Thyroid-stimulating antibody (TSAb) and TSH-binding inhibitor immunoglobulin (TBII) have been measured as TRAb to diagnose Graves' disease and to follow Graves' patients. We intended to evaluate the clinical value of TRAb (TSAb and TBII) assay in establishing the diagnosis of Graves' disease and in predicting its clinical course. TSAb and TBII were studied in 686 normal subjects and in 277 Graves' patients before antithyroid drug therapy. We followed serial changes of TSAb and TBII in 30 Graves' patients before, during and after antithyroid drug therapy over 3.5-9 yr. We measured TSAb as a stimulator assay and TBII as a receptor assay. Both TSAb and TBII were distributed normally in 686 normal subjects. ROC curves demonstrated that both TSAb and TBII had high sensitivity and specificity for the diagnosis of Graves' disease, and were equally sensitive and specific; 150% was chosen as cut-off value for TSAb and 10% for TBII. Of the 277 untreated Graves' patients, 254 (92%) had positive TSAb and positive TBII. All of the 277 untreated Graves' patients had positive TRAb (TSAb and/or TBII). We followed the serial changes of TSAb and TBII in 30 Graves' patients over 3.5-9 yr. During antithyroid drug therapy, TSAb and TBII activities decreased and disappeared in 27 patients (Group A), but continued to be high in the other 3 (Group B). The former 27 Group A patients achieved remission, but the latter 3 Group B patients continued to have hyperthyroidism. Of the 27 Group A patients, 16 (59%) had parallel decreases of TSAb and TBII activities; in 6, the changes were predominantly observed in either TSAb or TBII, and in 4, complex changes in TSAb and TBII activities were observed. Disappearance of TSAb and appearance of TSBAb was seen in one. The other 3 Group B patients continued to have high TSAb and TBII activities and to have hyperthyroidism. In conclusion, TSAb and TBII are of clinical value in establishing the diagnosis of Graves' disease and in predicting its clinical course. We clearly demonstrated its diagnostic usefulness. Both TSAb and TBII have high sensitivity and specificity. All of the 277 untreated Graves' patients had TRAb (TSAb and/or TBII). Serial changes of TSAb and TBII during therapy differ from one patient to another, and can be classified into several groups. Changes in TSAb and TBII activities reflect the clinical courses of Graves' patients. The simultaneous measurement of both TSAb and TBII is clinically useful, since TSAb and TBII reflect two different aspects of TRAb. TSAb and TBII are different.