The direct interaction of phospholipase C-gamma 1 with phospholipase D2 is important for epidermal growth factor signaling

The epidermal growth factor (EGF) receptor has an important role in cellular proliferation, and the enzymatic activity of phospholipase C (PLC)-gamma1 is regarded to be critical for EGF-induced mitogenesis. In this study, we report for the first time a phospholipase complex composed of PLC-gamma1 and phospholipase D2 (PLD2). PLC-gamma1 is co-immunoprecipitated with PLD2 in COS-7 cells. The results of in vitro binding analysis and co-immunoprecipitation analysis in COS-7 cells show that the Src homology (SH) 3 domain of PLC-gamma1 binds to the proline-rich motif within the Phox homology (PX) domain of PLD2. The interaction between PLC-gamma1 and PLD2 is EGF stimulation-dependent and potentiates EGF-induced inositol 1,4,5-trisphosphate (IP(3)) formation and Ca(2+) increase. Mutating Pro-145 and Pro-148 within the PX domain of PLD2 to leucines disrupts the interaction between PLC-gamma1 and PLD2 and fails to potentiate EGF-induced IP(3) formation and Ca(2+) increase. However, neither PLD2 wild type nor PLD2 mutant affects the EGF-induced tyrosine phosphorylation of PLC-gamma1. These findings suggest that, upon EGF stimulation, PLC-gamma1 directly interacts with PLD2 and this interaction is important for PLC-gamma1 activity.

Attenuation of signal flow from P2Y6 receptor by protein kinase C-alpha in SK-N-BE(2)C human neuroblastoma cells

Extracellular nucleotides exert a variety of biological actions through several kinds of P2 receptors in many tissues and cell types. We found that treatment with nucleotides increases intracellular Ca2+ concentration ([Ca2+]i) in SK-N-BE(2)C human neuroblastoma cells with a following order of potency: UDP > UTP > ADP >> ATP. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that specific mRNAs coding for human P2Y1, P2Y4, and P2Y6 receptors were expressed in the cells, but Northern blot analysis revealed that P2Y6 receptors were the predominant type. Activation of protein kinase C-alpha by treatment with 1 micro m phorbol 12-myristate 13-acetate dramatically inhibited both the UDP-induced [Ca2+]i rise and inositol 1,4,5-trisphosphate (IP3) generation, whereas incubation with pertussis toxin had little effect on the responses. The UDP-induced [Ca2+]i rise and IP3 production were maintained up to 30 min after stimulation, while bradykinin-induced responses rapidly decreased to the basal level within 5 min of stimulation. Pretreatment of cells with the maximal effective concentration of UDP reduced the subsequent carbachol- or bradykinin-induced [Ca2+]i rise without inhibition of IP3 generation. Neuronal differentiation of the cells by treatment with retinoic acid for 7 days did not change the expression level of P2Y6 receptors. Taken together, the data indicate that P2Y6 receptors highly responsive to diphosphonucleotide UDP are endogenously expressed in the human neuroblastoma SK-N-BE(2)C cells and that they are involved in the modulation of other phospholipase C-coupled receptor-mediated Ca2+ mobilization by depleting the IP3-sensitive Ca2+ stores.

Protein kinase A- and C-induced insulin release from Ca2+ -insensitive pools

Insulin secretion is known to depend on an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)). However, recent studies have suggested that insulin secretion can also be evoked in a Ca(2+)-independent manner. In the present study we show that treatment of intact mouse islets and RINm5F cells with protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) or protein kinase A (PKA) activator forskolin promoted insulin secretion with no changes of [Ca(2+)](i). Moreover, insulin secretion mediated by PMA or forskolin was maintained even when extracellular or cytosolic Ca(2+) was deprived by treatment of cells with ethylene glycol bis(beta-amino ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) or 1,2-bis(2-amino phenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxy methyl ester) (BAPTA/AM) in RINm5F cells. The secretagogue actions of PMA and forskolin were blocked by GF109203X and H89, selective inhibitors for PKC and PKA, respectively. PMA treatment caused translocation of PKC-alpha and PKC- epsilon from cytosol to membrane, implying that selectively PKC-alpha and PKC- epsilon isoforms might be important for insulin secretion. Co-treatment with high K(+) and PMA showed a comparable level of insulin secretion to that of PMA alone. In addition, PMA and forskolin evoked insulin secretion in cells where Ca(2+)-dependent insulin secretion was completed. Our data suggest that PKC and PKA can elicit insulin secretion not only in a Ca(2+)-sensitive manner but also in a Ca(2+)-independent manner from separate releasable pools.

Activation of B2 bradykinin receptors by neurotensin

Many previous reports suggested that relatively high concentrations of neurotensin were required to exert its effects on neurotransmitter secretion. The neurotensin binding sites, which recognize high concentrations of neurotensin, were characterized in rat pheochromocytoma (PC12) cells. When PC12 cells were treated with neurotensin, [3H]norepinephrine secretion and elevation of cytosolic calcium were evoked at EC(50) values of 59+/-4 and 37+/-7 microM, respectively. Both calcium release and inositol 1,4,5-trisphosphate (IP(3)) production induced by neurotensin suggested involvement of phospholipase C. Experiments with simultaneous or sequential treatment with neurotensin and bradykinin suggested that neurotensin and bradykinin act on the same binding sites. Furthermore, both inhibition of bradykinin- and neurotensin-induced calcium rises by bradykinin receptor antagonists with similar IC(50) values and receptor binding analysis using [3H]bradykinin confirmed that neurotensin directly binds to B2 bradykinin receptors. The data suggest that neurotensin binds and activates the B2 bradykinin receptors.

Enhancement of B-MYB transcriptional activity by ZPR9, a novel zinc finger protein

By using the yeast two-hybrid system, the zinc finger protein ZPR9 was identified as one of the B-MYB interacting proteins that associates with the carboxyl-terminal conserved region of B-MYB. ZPR9 was found to form in vivo complexes with B-MYB, as demonstrated by in vivo binding assay and coimmunoprecipitation experiments of the endogenously and exogenously expressed proteins. Deletion analysis revealed that this binding was mediated by all three functional domains, an amino-terminal DNA-binding domain, a transactivation domain, and a carboxyl-terminal conserved region of B-MYB. We show that the interaction of ZPR9 with B-MYB is functional because cotransfection of ZPR9 significantly up-regulates B-MYB transcriptional activity in a dose-dependent manner. In addition, coexpression of ZPR9 with B-MYB caused the accumulation of B-MYB, as well as ZPR9, in the nucleus. Furthermore, constitutive expression of ZPR9 in human neuroblastoma cells induces apoptosis in the presence of retinoic acid. These results strongly suggest that ZPR9 plays an important role in modulation of the transactivation by B-MYB and cellular growth of neuroblastoma cells.

Inhibition of acetylcholine-mediated effects by borneol

We previously reported that the aqueous extract from a medicinal plant Dryobalanops aromatica specifically inhibits the nicotinic acetylcholine receptor (nAChR) (Oh et al. Pharmacol Res 2000;42(6):559-64). Here, the effect of borneol, the main constituent of D. aromatica, on nAChR activity was investigated in bovine adrenal chromaffin cells. Borneol inhibited a nAChR agonist 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP)-induced calcium increase with a half maximal inhibitory concentration (IC(50)) of 56+/-9 microM. In contrast, borneol did not affect the calcium increases induced by high K+, veratridine, and bradykinin. The sodium increase induced by DMPP was also inhibited by borneol with similar potency (49+/-12 microM), suggesting that the activity of nAChRs is inhibited by borneol. Borneol inhibited DMPP-induced secretion of [3H]norepinephrine with an IC(50) of 70+/-12 microM. Carbon-fiber amperometry also confirmed the inhibition of DMPP-induced exocytosis by borneol in single chromaffin cells. [3H]nicotine binding, however, was not affected by borneol. The inhibitory effect by borneol is more potent than the effect by lidocaine, a commonly used local anesthetic. The data suggest that borneol specifically inhibits the nAChR-mediated effects in a noncompetitive way.

Heterogeneous nuclear ribonucleoprotein C modulates translation of c-myc mRNA in a cell cycle phase-dependent manner

The c-myc proto-oncogene plays a key role in the proliferation, differentiation, apoptosis, and regulation of the cell cycle. Recently, it was demonstrated that the 5' nontranslated region (5' NTR) of human c-myc mRNA contains an internal ribosomal entry site (IRES). In this study, we investigated cellular proteins interacting with the IRES element of c-myc mRNA. Heterogeneous nuclear ribonucleoprotein C (hnRNP C) was identified as a cellular protein that interacts specifically with a heptameric U sequence in the c-myc IRES located between two alternative translation initiation codons CUG and AUG. Moreover, the addition of hnRNP C1 in an in vitro translation system enhanced translation of c-myc mRNA. Interestingly, hnRNP C was partially relocalized from the nucleus, where most of the hnRNP C resides at interphase, to the cytoplasm at the G(2)/M phase of the cell cycle. Coincidently, translation mediated through the c-myc IRES was increased at the G(2)/M phase when cap-dependent translation was partially inhibited. On the other hand, a mutant c-myc mRNA lacking the hnRNP C-binding site, showed a decreased level of translation at the G(2)/M phase compared to that of the wild-type message. Taken together, these findings suggest that hnRNP C, via IRES binding, modulates translation of c-myc mRNA in a cell cycle phase-dependent manner.

Phosphorylation of a novel zinc-finger-like protein, ZPR9, by murine protein serine/threonine kinase 38 (MPK38)

We have identified previously a new murine protein serine/threonine kinase, MPK38, closely related to the sucrose-non-fermenting protein kinase family [Gil, Yang, Lee, Choi and Ha (1997) Gene 195, 295-301]. Using the C-terminal half of the putative human counterpart of MPK38, HPK38, as a bait in a yeast two-hybrid screen of a human HeLa cDNA library, it was discovered that the zinc-finger-motif-containing protein, termed zinc-finger-like protein 9 (ZPR9), bound both HPK38 and MPK38. In a co-expression assay, ZPR9 associated with MPK38 in vivo, and we showed that the ZPR9 is also phosphorylated by MPK38. In addition, ZPR9 physically interacts with itself in mammalian cells. The ZPR9 cDNA hybridized with a mRNA species of approx. 1.7 kb in Northern-blot analysis. The ZPR9 transcript was detected in all tissues examined, including lung, kidney, spleen,liver and brain. Co-expression of ZPR9 with MPK38 caused the accumulation of ZPR9 in the nucleus. These findings suggest a potentially important role for ZPR9 in MPK38-mediated signal transduction, and that ZPR9 is a physiological substrate of MPK38 in vivo.

Blocking of acidosis-mediated apoptosis by a reduction of lactate dehydrogenase activity through antisense mRNA expression

Lactic acid produced from the cells is a potential cause of extra- and intracellular acidification. Due to scarce technical tools, lactic acid that leads to acidification could not be reduced and direct evidence of the relationship between metabolic lactate and apoptosis has not yet been elucidated. In this study, we designed a cellular pH regulation system in CHO cells by a reduction of lactate dehydrogenase (LDH) activity through LDH antisense mRNA expression. This inhibited lactate production and, therefore, acidification of the cytosol. Under HCO3(-)-buffered growth conditions, both the parent CHO cells and the engineered CHO cells maintained their extracellular pH and intracellular pH fairly well. However, upon acidification of the cytosol, only the parent CHO cells underwent apoptosis under HCO3(-)-free conditions. In fact, we observed a number of apoptosis-related events only in control cells, including mitochondrial dysfunction, cytochrome c release, and an increase in caspase-3 enzymatic activity.

Low-dose levalbuterol in children with asthma: safety and efficacy in comparison with placebo and racemic albuterol

BACKGROUND

Racemic albuterol (RAC) is an equal mixture of (R)-albuterol and (S)-albuterol. Only the (R)-isomer, levalbuterol (LEV), is therapeutically active. Lower doses of LEV, devoid of (S)-albuterol, have demonstrated efficacy comparable to that of higher doses of the (R)-isomer administered as a component of RAC.

OBJECTIVE

The purpose of this study was to determine whether LEV results in improved safety and efficacy in children.

METHODS

Asthmatic children aged 4 to 11 years (n = 338; FEV(1), 40% to 85% of predicted) participated in this multicenter, randomized, double-blinded study and received 21 days of 3-times-a-day treatment with nebulized LEV (0.31 or 0.63 mg), RAC (1.25 or 2.5 mg), or placebo. The primary endpoint was FEV(1) (peak percent change). Adverse events, clinical laboratory test results, vital signs, and electrocardiograms were evaluated for safety.

RESULTS

All active treatments significantly improved the primary endpoint in comparison with placebo (P < .001). Significant differences in FEV(1) were noted immediately after nebulization (median change, 2.0%, 19.0%, 18.1%, 12.4%, and 15.6% for placebo, LEV 0.31 and 0.63, RAC 1.25 and 2.5 mg, respectively; P < .05 vs placebo; P < .05 for LEV 0.31 and 0.63 vs RAC 1.25 mg). LEV 0.31 mg was the only treatment not different from placebo for changes in ventricular heart rate, QT(c) interval, and glucose (P > .05). All active treatments decreased serum potassium (range, -0.3 to -0.6; P < .002 vs placebo), and RAC 2.5 mg caused the greatest change (P < .005 vs other actives). In a patient subset with severe asthma, a dose-response relationship was observed for levalbuterol, indicating that higher doses were more effective.

CONCLUSION

LEV was clinically comparable to 4- to 8-fold higher doses of RAC, and it demonstrated a more favorable safety profile. LEV 0.31 mg should be used as the starting dose in 4-11 year old children with mild to moderate persistent asthma. Patients with severe disease might benefit from higher doses.

Fine-needle aspiration cytology of pleuropulmonary blastoma: a case report with unusual features

Pleuropulmonary blastoma (PPB) is a rare and aggressive intrathoracic neoplasm of childhood, typically presenting as a pulmonary and/or pleural-based mass with cystic, solid, or combined features. Histologically, the tumor is well characterized with a mixture of primitive mesenchymal and variably differentiated sarcomatous components, and the cytologic features described in the three previous reports are also compatible to the histologic ones. Now, we present another case of PPB showing unusual features. A 3-yr-old boy presented with a pleural- or chest wall-based tumor. The fine-needle aspiration cytologic smears were highly cellular with poorly differentiated cells showing variable size and shape rather than those of typical blastemal cells. The histologic findings were also distinctive, exhibiting diffuse sheets of poorly differentiated cells without typical blastemal cell component. Diagnosis was confirmed by the support of immunohistochemical and ultrastructural features. The patient underwent a typical aggressive clinical course to death within 8 mo after diagnosis.

A simple and secure technique for tracheal T-tube insertion

We describe a simple and secure technique for the insertion of a long Montgomery type T-tube in patients with tracheal stenosis. An endotracheal tube is placed into the lumen of the T-tube and by maintaining the airway during insertion, the technique has been found to be safe and it can prevent the kind of tracheal damage occurring with blind techniques.

Potentiation of PGE(2)-mediated cAMP production during neuronal differentiation of human neuroblastoma SK-N-BE(2)C cells

The prostaglandin-evoked cAMP production was studied in human neuroblastoma SK-N-BE(2)C cells during neuronal differentiation induced by all-trans retinoic acid. The incubation with 5 microM all-trans retinoic acid for 4-6 days promoted neurite outgrowth of cells. After differentiation, prostaglandin E(2) (PGE(2))-induced cAMP production was dramatically increased, whereas forskolin- and AlF-induced cAMP productions were not changed. The increase reached maximum after 4-days of incubation with all-trans retinoic acid. The differentiation caused an increase in the maximal response and a decrease in the half-maximal effective concentration of the PGE(2)-induced cAMP production. In addition, the binding of [(3)H]PGE(2) to membrane receptors was enhanced in differentiated cells. However, the order of potency of the various prostaglandins (PGE(1) = PGE(2) > PGD(2) = PGF(2alpha) = PGI(2)) in cAMP production did not change during the differentiation, suggesting that mainly E-prostanoid (EP) receptors were involved. Butaprost, an EP(2) receptor specific agonist, increased the cAMP level in a concentration dependent manner and had a similar potentiating effect on cAMP production as PGE(2) upon differentiation. Northern blot analysis using the human cDNA probes shows that the EP(2) mRNA level was about seven times higher in differentiated cells, while the dopamine beta-hydroxylase (DBH) mRNA completely disappeared. Our results, thus, suggest that elevated gene expression of the prostanoid EP(2) receptor results in an increase in the PGE(2)-evoked cAMP production in SK-N-BE(2)C cells during neuronal differentiation.

Pharmacological characterization of adenosine receptors in PGT-beta mouse pineal gland tumour cells

1. The adenosine receptor in mouse pinealocytes was identified and characterized using pharmacological and physiological approaches. 2. Expression of the two adenosine receptor subtypes A2B and A3 was detected in mouse pineal glands and PGT-beta cells by polymerase chain reaction and nucleotide sequencing. 3. Adenosine and 5'-N-ethylcarboxamidoadenosine (NECA) evoked cyclic AMP generation but the A2)-selective agonist 2-(4-(2-carboxyethyl)phenylethylamino)adenosine-5'-N-ethylcarboxamideadenosine (CGS 21680) and the A1-specific agonists R-N(6)-(2-phenylisopropyl)adenosine (R-PIA) and N(6)-cyclopentyladenosine (CPA) had little effect on intracellular cyclic AMP levels. The A2B receptor selective antagonists alloxazine and enprofylline completely blocked NECA-mediated cyclic AMP accumulation. 4. Treatment of cells with the A3-selective agonist N(6)-(3-iodobenzyl)-5'-(N-methylcarbamoyl)adenosine (IB-MECA) inhibited the elevation of the cyclic AMP level induced by NECA or isoproterenol in a concentration-dependent manner with maximal inhibition of 40 - 50%. These responses were blocked by the specific A3 adenosine receptor antagonist MRS 1191. Pretreatment of the cells with pertussis toxin attenuated the IB-MECA-induced responses, suggesting that this effect occurred via the pertussis toxin-sensitive inhibitory G proteins. 5. IB-MECA also caused a concentration-dependent elevation in [Ca(2+)]i and IP3 content. Both the responses induced by IB-MECA were attenuated by treatment with U73122 or phorbol 12-myristate 13-acetate. 6. These data suggest the presence of both A2B and A3 adenosine receptors in mouse pineal tumour cells and that the A2B receptor is positively coupled to adenylyl cyclase whereas the A3 receptor is negatively coupled to adenylyl cyclase and also coupled to phospholipase C.

P2X7 nucleotide receptor mediation of membrane pore formation and superoxide generation in human promyelocytes and neutrophils

The P2X(7) receptor, which induces cation channel opening imparting significant permeability to Ca2+ and pore formation with changes in the plasma membrane potential, has been known to be rather restrictedly expressed in cells of the macrophage lineage including dendrites, mature macrophages, and microglial cells. However, we show here that the P2X(7) receptor is also expressed in cells of granulocytic lineage such as HL-60 promyelocytes, granulocytic differentiated cells, and neutrophils. Exposure of these cells to 2',3'-O-(4-benzoyl)benzoyl-ATP (BzATP) triggered intracellular Ca2+ rise through the mediation of phospholipase C-independent and suramin-sensitive pathways. BzATP also induced depolarization of the plasma membrane in the absence of extracellular Ca2+, whereas it hyperpolarized the cells in the presence of external Ca2+, probably in part through the activation of Ca2+-activated K(+) channels. However, the hyperpolarization phenomenon was markedly attenuated in differentiated HL-60 cells and neutrophils. RT-PCR and Northern blot analysis revealed the presence of P2X(7) receptors on both HL-60 and neutrophil-like cells. This was further confirmed by pore formation through which the uptake of Lucifer yellow and YO-PRO1 occurred on BzATP treatment. BzATP stimulated in a concentration-dependent manner the production of superoxide in differentiated HL-60 cells via a pathway partially dependent on extracellular Ca2+. Moreover, in human neutrophils, BzATP was a more effective inducer of superoxide generation than PMA. Taken together, this is a first demonstration of the expression of P2X(7) receptors on neutrophils, which shows that the receptor is functionally involved in the defense mechanism by activation of the respiratory burst pathway.

Inhibition of H2 histamine receptor-mediated cation channel opening by protein kinase C in human promyelocytic cells

Histamine, through H(2) receptors, triggers a prominent rise in intracellular free Ca(2+) concentration ([Ca(2+)](i)) in addition to an elevation of cAMP level in HL-60 promyelocytes. Here we show that the histamine-induced [Ca(2+)](i) rise was due to influx of Ca(2+) from the extracellular space, probably through nonselective cation channels, as incubation of the cells with SKF 96365 abolished the histamine-induced [Ca(2+)](i) rise, Na(+) influx, and membrane depolarization. The Ca(2+) influx was specifically inhibited by pretreatment of the cells with PMA or extracellular ATP with 50% inhibitory concentrations of 0.12 +/- 0.03 nM and 185 +/- 17 microM, respectively. Western blot analysis of protein kinase C (PKC) isoforms revealed that PMA (< or =1 nM) and ATP (300 microM) caused selective translocation of PKC-delta to the particulate/membrane fraction. Costimulation of the cells with histamine and SKF 96365 partially reduced histamine-induced granulocytic differentiation, which was evaluated by looking at the extent of fMet-Leu-Phe-induced [Ca(2+)](i) rise and superoxide generation. In conclusion, nonselective cation channels are opened by stimulation of the H(2) receptor, and the channels are at least in part involved in the induction of histamine-mediated differentiation processes. Both effects of histamine were selectively inhibited probably by the delta isoform of PKC in HL-60 cells.

Ten-year survival of patients with locally advanced, stage ib-iib cervical cancer after neoadjuvant chemotherapy and radical hysterectomy

OBJECTIVE(S)

The aim of this study was to evaluate the effects of neoadjuvant chemotherapy and radical hysterectomy on long-term survival in stage IB-IIB locally advanced cervical cancer by conducting a 10-year follow-up.

METHODS

Between August 1983 and May 1990, 80 locally advanced, stage IB-IIB cervical cancer patients with tumor diameter greater than or equal to 4 cm were treated with neoadjuvant VBP chemotherapy (cisplatin, vinblastine, and bleomycin) followed by radical hysterectomy with pelvic lymphadenectomy. After this therapeutic modality, patients were followed for more than 10 years. Ten-year survival rates and factors affecting recurrence after this therapy were evaluated.

RESULTS

Of 80 patients, 75 (93.7%) showed a reduction in tumor size after neoadjuvant chemotherapy. At pathologic examination, stage reduction was noted in 53 (66.2%) patients and 20 patients (25%) showed no residual or microinvasive cervical tumor. Pelvic lymph node metastases were found in 17 patients (21.3%). During the 10-year follow up, 2 patients were lost and 16 patients recurred. Overall 5-year and 10-year disease-free actual survival rates were 82.0 (64/78) and 79.4% (62/78), respectively. Clinical stage, initial tumor size, clinical response, and residual tumor size were not risk factors for recurrence after this therapy. However, pelvic lymph node metastasis was a significant risk factor for recurrence.

CONCLUSION(S)

Neoadjuvant VBP chemotherapy followed by radical hysterectomy in locally advanced, stage IB-IIB cervical cancer patients seemed to improve the long-term survival rate for these patients compared to that of conventional therapy. However, randomized controlled trials are needed to confirm this result.

Effects of polychlorinated biphenyl 19 (2,2',6-trichlorobiphenyl) on contraction, Ca2+ transient, and Ca2+ current of cardiac myocytes

Polychlorinated biphenyls (PCBs) have been known as serious environmental pollutants, causing developmental delays, motor dysfunction, and decrease in brain dopamine level in humans and animals. We have investigated the effects of a PCB congener, 2,2',6-trichlorobiphenyl (PCB 19) on contractile force, Ca2+ transient, and L-type Ca2+ current (I(Ca,L)) in guinea pig ventricular myocytes stimulated at a rate of 0.25-0.33 Hz. PCB 19 decreased contractile force in a concentration-dependent manner. During the negative inotropic response, the action potential duration at 20% (APD20), 90% of repolarization (APD90), and the action potential amplitude (APA) were decreased concentration dependently: 30 microM PCB 19 reduced APD20, APD90 and APA by 36.7 +/- 3.5%, 22.6 +/- 3.9%, and 2.4 +/- 0.6%, respectively (n = 11, p < 0.01). PCB 19 30 microM decreased the Ca2+ transient and the I(Ca,L) by 46.8 +/- 1.8% (n = 9, p < 0.01) and 47.1 +/- 3.1% (n = 9, p < 0.01), respectively. The results suggest that PCB 19 decreased the Ca2+ transient through inhibition of L-type Ca2+ channels and that the decreased Ca2+ transient consequently caused a negative inotropic effect in cardiac myocytes.

Characteristics of body heat balance of paraplegics during exercise in a hot environment

The purpose of this investigation was to clarify the characteristics of body temperature regulation in paraplegics due to spinal cord injury (SCI) during an arm cranking exercise in a hot environment. Twelve paraplegics with lesions located between Th3 and L1,2 and seven able-bodied subjects (AB) participated in this study. The subjects were exposed to a hot (33 degrees C) or a moderate temperature (25 degrees C) environment for one hour and during the last 10 min of the exposure, the subjects performed arm cranking exercises at an exercise intensity of 40 W. The skin temperatures at the chest, the upper arm, the thigh and the calf, the tympanic membrane temperature (Tty), and the skin blood flow of the thigh (SBFT) were continuously monitored during the experiment. Although no systematical variation was found in the Tty at 25 degrees C, the Tty at 33 degrees C in paraplegics during exercise was significantly greater than that at rest (P < 0.01), which indicated a pronounced heat stress for paraplegics at 33 degrees C. SBFT of paraplegics with high lesions of the SCI remained unchanged during the experiment at 25 degrees C and 33 degrees C, while paraplegics with low lesions in this study showed consecutive increases in SBFT during exercise in both environmental conditions similar to AB. The increased core temperature in paraplegics with high lesions was considered to be due to a lack of sweat response and vasomotor activity in the paralyzed area. On the basis of the findings in this study, it can be suggested that high core temperature without any increment of SBFT may be characterized as body heat balance of paraplegics with high lesions during exercise in a hot environment.

Selective inhibition of beta(2)-adrenergic receptor-mediated cAMP generation by activation of the P2Y(2) receptor in mouse pineal gland tumor cells

Rhythmic noradrenergic signaling from the hypothalamic clock in the suprachiasmatic nucleus to the pineal gland causes an increase in intracellular cAMP which regulates the circadian fluctuation of melatonin synthesis. The activation of phospholipase C (PLC)-coupled P2Y(2) receptors upon treatment with ATP and UTP exclusively inhibited the isoproterenol-stimulated cAMP production in mouse pineal gland tumor cells. However, the activation of other PLC-coupled receptors including P2Y(1) and bombesin receptors had little or no effect on the isoproterenol-stimulated cAMP production. Also, ATP did not inhibit cAMP production caused by forskolin, prostaglandin E(2), or the adenosine analog NECA. These results suggest a selective coupling between signalings of P2Y(2) and beta(2)-adrenergic receptors. The binding of [(3)H]CGP12177 to beta(2)-adrenergic receptors was not effected by the presence of ATP or UTP. Ionomycin decreased the isoproterenol-stimulated cAMP production, whereas phorbol 12-myristate 13-acetate slightly potentiated the isoproterenol response. Chelation of intracellular Ca(2+), however, had little effect on the ATP-induced inhibition of cAMP production, while it completely reversed the ionomycin-induced inhibition. Treatment of cells with pertussis toxin almost completely blocked the inhibitory effect of nucleotides. Pertussis toxin also inhibited the nucleotide-induced increase in intracellular Ca(2+) and inositol 1,4,5-trisphosphate production by 30-40%, suggesting that the ATP-mediated inhibition of the cAMP generation and the partial activation of PLC are mediated by pertussis toxin-sensitive G(i)-protein. We conclude that one of the functions of P2Y(2) receptors on the pineal gland is the selective inhibition of beta-adrenergic receptor-mediated signaling pathways via the inhibitory G-proteins.

Sonographic evaluation of gallbladder-wall thickening in hemorrhagic fever with renal syndrome: prediction of disease severity

PURPOSE

Gallbladder-wall thickening (GBWT) frequently occurs in patients with hemorrhagic fever with renal syndrome (HFRS), an acute infectious disease caused by hantaviruses. HFRS is manifested by fever, hemorrhage, renal failure, and in many cases gastrointestinal symptoms, such as abdominal pain and tenderness. The clinical significance of GBWT in HFRS has not been reported. The purpose of this study was to investigate the incidence of GBWT and the relationship between GBWT and the severity of HFRS.

METHODS

We retrospectively reviewed the medical records and sonograms of 68 patients with HFRS (47 males and 21 females, with an age range of 10-76 years) who underwent abdominal sonography in the acute stage of the disease. We measured the gallbladder-wall thickness on the sonograms and reviewed other sonographic and radiographic findings. Clinical factors that reflect the severity of HFRS were compared between the patients with GBWT (defined as thickness of 4 mm or more) and those without GBWT.

RESULTS

Of the 68 patients, 29 (43%) had GBWT, which was even and diffuse in all cases. The patients with GBWT had a significantly lower mean platelet count and serum albumin level and significantly higher serum aspartate aminotransferase and serum lactate dehydrogenase levels than did the patients without GBWT. In addition, the incidence of renal failure requiring hemodialysis and the incidences of ascites and pleural effusion were higher in the patients with GBWT than in those without GBWT. Five patients died of HFRS; all 5 had GBWT (p = 0.011 for comparison with patients without GBWT).

CONCLUSIONS

Our results suggest that the sonographic measurement of gallbladder-wall thickness during the acute stage of HFRS is useful for determining the severity of HFRS.

Regulation of macrophage migration inhibitory factor and thiol-specific antioxidant protein PAG by direct interaction

Macrophage migration inhibitory factor (MIF) is an important mediator that plays a central role in the control of the host immune and inflammatory response. To investigate the molecular mechanism of MIF action, we have used the yeast two-hybrid system and identified PAG, a thiol-specific antioxidant protein, as an interacting partner of MIF. Association of MIF with PAG was found in 293T cells transiently expressing MIF and PAG. The use of PAG mutants (C52S, C71S, and C173S) revealed that this association was significantly affected by C173S, but not C52S and C71S, indicating that a disulfide involving Cys(173) of PAG is responsible for the formation of MIF-PAG complex. In addition, the interaction was highly dependent on the reducing conditions such as dithiothreitol or beta-mercaptoethanol but not in the presence of H2O2. Analysis of the activities of the interacting proteins showed that the D-dopachrome tautomerase activity of MIF was decreased in a dose-dependent manner by coexpression of wild-type PAG, C52S, and C71S, whereas C173S was almost ineffective, suggesting that the direct interaction may be involved in the control of D-dopachrome tautomerase activity of MIF. Moreover, MIF has been shown to bind to PAG and it also inhibits the antioxidant activity of PAG.

Coupling of L-type voltage-sensitive calcium channels to P2X(2) purinoceptors in PC-12 cells

Extracellular ATP elevates cytosolic Ca(2+) by activating P2X and P2Y purinoceptors and voltage-sensitive Ca(2+) channels (VCCCs) in PC-12 cells, thereby facilitating catecholamine secretion. We investigated the mechanism by which ATP activates VSCCs. 2-Methylthioadenosine 5'-triphosphate (2-MeS-ATP) and UTP were used as preferential activators of P2X and P2Y, respectively. Nifedipine inhibited the ATP- and 2-MeS-ATP-evoked cytosolic Ca(2+) concentration increase and [(3)H]norepinephrine secretion, but not the UTP-evoked responses. Studies with Ca(2+) channel blockers indicated that L-type VSCCs were activated after the P2X activation. Mn(2+) entry profiles and studies with thapsigargin revealed that Ca(2+) entry, rather than Ca(2+) release, was sensitive to nifedipine. Although P2X(2) and P2X(4) receptor mRNAs were detected, studies with pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid revealed that P2X(2) was mainly coupled to the L-type VSCCs. The inhibitory effect of nifedipine did not occur in the absence of extracellular Na(+), suggesting that Na(+) influx, which induces depolarization, was essential for the P2X(2)-mediated activation of VSCCs. We report that depolarization induced by Na(+) entry through the P2X(2) purinoceptors effectively activates L-type VSCCs in PC-12 cells.

Noncompetitive inhibition by camphor of nicotinic acetylcholine receptors

The effect of camphor, a monoterpenoid, on catecholamine secretion was investigated in bovine adrenal chromaffin cells. Camphor inhibited [3H]norepinephrine ([3H]NE) secretion induced by a nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), with a half-maximal inhibitory concentration (IC50) of 70 +/- 12 microM. In addition, camphor inhibited the rise in cytosolic calcium ([Ca2+]i) and sodium ([Na+]i) induced by DMPP with IC50 values of 88 +/- 32 and 19 +/- 2 microM, respectively, suggesting that the activity of nAChRs is also inhibited by camphor. On the other hand, binding of [3H]nicotine to nAChRs was not affected by camphor. [Ca2+]i increases induced by high K+, veratridine, and bradykinin were not affected by camphor. The data suggest that camphor specifically inhibits catecholamine secretion by blocking nAChRs without affecting agonist binding.

Role of titin in nonmuscle and smooth muscle cells

Extensive investigation of vertebrate striated muscle titin has yielded significant insight into its structure and function in striated muscle. We have begun to investigate other members of the titin protein family found in vertebrate smooth muscle and nonmuscle cells. Smooth and nonmuscle titins resemble striated muscle titin in molecular size and morphology but differ in their interactions with myosin II filaments and in the structural contexts in which they exist in vivo. Divergence of these titins from the muscle titin paradigm demonstrates the versatility of this remarkable family of giant proteins.

Modulation of H2 histamine receptor-mediated cAMP generation and granulocytic differentiation by extracellular nucleotides via activation of protein kinase C

Extracellular ATP exerts a variety of biological actions through several kinds of P2 receptor in HL-60 promyelocytes. We show that stimulation of P2Y2 receptors with ATP and analogs resulted in the inhibition of a subsequently histamine-induced cAMP production and functional differentiation. Treatment of the cells with phorbol 12-myristate 13-acetate also blocked the histamine-mediated cAMP generation just as ATP did. Incubation of the cells with the protein kinase C inhibitor bisindolylmaleimide (GF109203X) abolished the inhibitory effects of extracellular nucleotides, suggesting that protein kinase C may act as an inter-regulator between two receptors. However, ATP did not affect the binding affinity or total binding of [3H]histamine to membrane receptors; it also did not heterologously desensitize H2 receptors. The ATP treatment synergistically elevated the cAMP levels induced directly by forskolin or indirectly by G protein activation after cholera toxin treatment. This indicates that the site of the protein kinase C action is not the G protein or effector enzyme. Co-stimulation of the cells with nucleotides and histamine inhibited histamine-mediated granulocytic differentiation, which was evaluated by looking at the extent of N-formyl-methionyl-leucyl-phenylalanine responses. Taken together, the results demonstrate that extracellular nucleotides are negatively involved in the modulation of histamine signaling via activation of protein kinase C, probably by inhibiting coupling between receptor and G protein.

Chlorpromazine inhibits store-operated calcium entry and subsequent noradrenaline secretion in PC12 cells

1. The effect of chlorpromazine on the store-operated Ca2+ entry activated via the phospholipase C signalling pathway was investigated in PC12 cells. 2. Chlorpromazine inhibited the sustained increase after the initial peak in the intracellular Ca2+ concentration produced by bradykinin while having no effect on the initial transient response. The inhibition was lowered by the removal of extracellular free Ca2+. However, chlorpromazine did not inhibit bradykinin-induced inositol 1,4,5-trisphosphate production. 3. Chlorpromazine inhibited the bradykinin-induced noradrenaline secretion in a concentration-dependent manner (IC(50): 24+/-5 microM, n=3). 4. To test for a direct effect of chlorpromazine on store-operated Ca2+ entry, thapsigargin, an inhibitor of microsomal Ca(2+)-ATPase, was used to induce store-operated Ca2+ entry in PC12 cells. Chlorpromazine reduced the thapsigargin-induced sustained Ca2+ level (IC(50): 24+/-2 microM, n=3), and the inhibition also occluded the inhibitory action of 1-[-[3-(4-methoxyphenyl) propoxy]-4-methoxyphenyl]-1H-imidazole hydrochloride (SK&F96365). 5. The results suggest that chlorpromazine negatively modulates the store-operated Ca2+ entry activated subsequent to PLC activation.

Inhibition of nicotinic receptor-mediated catecholamine secretion by Dryobalanops aromatica in bovine adrenal chromaffin cells

Effect of the aqueous extract from a medicinal plant Dryobalanops aromatica(Dipterocarpaceae) on catecholamine secretion was investigated in bovine adrenal chromaffin cells. The aqueous extract inhibited [(3)H]norepinephrine ([(3)H]NE) secretion induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nicotinic acetylcholine receptor (nAChR) agonist, with a half-maximal inhibitory concentration (IC(50)) of 8.4 +/- 1.7 microgml(-1). Increases in cytosolic calcium ([Ca(2+)](i)) and sodium ([Na(+)](i)) induced by DMPP were also inhibited by the extract. However, the binding of [(3)H]nicotine to nAChRs was not affected by the addition of the extract in receptor binding competition analysis, suggesting that active components in the extract and nicotine do not share the binding site in the nAChR. On the other hand, [Ca(2+)](i)increases induced by high K(+), ionomycin, bradykinin, angiotensin II, and thapsigargin were not inhibited by the extract. The data suggest that the extract from D. aromatica specifically inhibits catecholamine secretion by blocking nAChR in a noncompetitive manner.

Fluticasone propionate versus zafirlukast: effect in patients previously receiving inhaled corticosteroid therapy

BACKGROUND

The use of inhaled corticosteroids compared with leukotriene modifying drugs in the treatment of persistent asthma has not been extensively studied.

OBJECTIVE

To compare the efficacy and safety of a low dose of fluticasone propionate (FP) and zafirlukast in patients previously maintained on inhaled corticosteroids.

METHODS

Patients (> or = 12 years old; FEV1 = 60% to 85% of predicted) with persistent asthma who were previously treated with low doses of triamcinolone acetonide (TAA) 400 to 800 microg/day or beclomethasone dipropionate (BDP) 168 to 336 microg/day were randomized to treatment with FP aerosol 88 microg BID (FP, n = 221) or zafirlukast 20 mg BID (n = 216) over 6 weeks.

RESULTS

Treatment with FP significantly increased the mean change at endpoint (the last post-baseline observation) in FEV1 (0.22 L versus 0.03 L, P < .001), morning PEF (17.8 versus 3.1 L/min, P = .004), evening PEF (16.7 versus 2.6 L/min, P = .002), the percentage of symptom-free days (16.2 versus 7.1%, P = .007), and the percentage of rescue-free days (23.4 versus 9.3%, P < .001), and significantly decreased rescue albuterol use (-0.66 puffs/day versus an increase of 0.27 puffs/day, P < .001) and combined symptom scores (-0.13 versus an increase of 0.08, P < .001) compared with zafirlukast. Treatment with FP maintained the percentage of awakening-free nights (-1.0 +/- 1.0); in contrast, treatment with zafirlukast reduced the percentage of awakening-free nights (-9.0 +/- 1.6, P < .001). A clinically meaningful difference (change of > or = 0.5; P < .001) was observed between FP and zafirlukast in the Asthma Quality of Life Questionnaire (AQLQ) global score and for each domain score except activity limitation (change of 0.3, P < .001). Significantly more patients in the zafirlukast group experienced an asthma exacerbation (n = 14) compared with FP-treated patients (n = 5, P = .035). Patients in the zafirlukast group were significantly more likely to be withdrawn due to lack of efficacy (P < .001).

CONCLUSION

Switching patients from low doses of inhaled corticosteroids to a lower total microgram dose of FP improves pulmonary function, asthma symptoms, and quality of life, while switching to the leukotriene receptor antagonist zafirlukast may result in worsening of asthma control. This was indicated by the significant number of zafirlukast-treated patients who were dropped from the study due to lack of efficacy within 6 weeks of discontinuing inhaled corticosteroids.

Loading of oxidizable transmitters into secretory vesicles permits carbon-fiber amperometry

Carbon-fiber amperometry detects oxidizable molecules released by exocytosis. We extended this electrochemical technique to cells that do not normally secrete oxidizable transmitters. We incubated AtT-20 cells, pituitary gonadotropes, cultured cerebellar granule cells, and yeast with high concentrations of dopamine (DA) and observed spontaneous and evoked quantal release of DA by amperometry. The rate of detectable spontaneous amperometric events was used as a measure of loading in AtT-20 cells. With 70 mm DA in the bath, loading was complete within 40 min. Cytoplasmic accumulation preceded vesicular loading. Loading decreased proportionally as the bath DA concentration was lowered. Loading rates were similar at 37 and 25 degrees C and much slower at 15 degrees C. Loading was blocked by bafilomycin A(1), a proton pump inhibitor, but not by bupropion, an inhibitor of the plasma membrane DA transporter. Other cells were tested. Spontaneous quantal events became more frequent and evoked events became larger and more frequent when PC12 cells were loaded with DA. Fluid-phase loading of neurons by short stimulation in DA solutions seemed selective for the synaptic vesicles. Thus, many cell types can be loaded with DA to study spontaneous and evoked exocytosis. The amine molecules enter these cells passively and may become concentrated in acidic vesicles by protonation.

Differential regulation of P2Y(11) receptor-mediated signalling to phospholipase C and adenylyl cyclase by protein kinase C in HL-60 promyelocytes

The regulatory mode of the P2Y(11) purinoceptor-mediated signalling cascades towards phospholipase C and adenylyl cyclase was studied in HL-60 promyelocytes. Treatment with the potent P2Y(11) receptor activator dATP evoked an elevated intracellular Ca(2+) concentration ([Ca(2+)](i)) and inositol 1,4,5-trisphosphate (IP(3)) production that was sustained for longer than 30 min. However, the dATP-induced responses were significantly inhibited by the activation of protein kinase C after a short exposure to phorbol 12-myristate 13-acetate (PMA). dATP also potently stimulated cyclic AMP production with half maximum effect seen at 23+/-7 microM dATP. In addition, a 5-min pretreatment with PMA enhanced the dATP-stimulated cyclic AMP accumulation. PMA potentiated the cyclic AMP production when adenylyl cyclase was activated directly by forskolin or indirectly by G protein activation after cholera toxin treatment. dATP also enhanced the forskolin-mediated cyclic AMP generation. Treatment of the cells with 10 microM U-73122, which almost completely blocked the dATP-stimulated IP(3) production and [Ca(2+)](i) rise, had no effect on cyclic AMP accumulation, while 10 microM 9-(tetrahydro-2-furyl)adenine (SQ 22536), which inhibited the adenylyl cyclase activation, did not effect the dATP-stimulated phosphoinositide turnover. Taken together, the results indicate that P2Y(11) receptor-mediated activation of phospholipase C and adenylyl cyclase occurs through independent pathways and is differentially regulated by protein kinase C in HL-60 cells.

Capsaicin inhibits platelet-activating factor-induced cytosolic Ca2+ rise and superoxide production

Platelet-activating factor (PAF) is an important participant in the inflammatory process. We studied the regulation of PAF activity by capsaicin in human promyelocytic leukemia HL-60 cells. Capsaicin inhibited PAF-induced superoxide production in a concentration-dependent manner. In addition to PAF, the fMLP- and extracellular ATP-induced superoxide productions were inhibited by capsaicin, whereas PMA-induced superoxide production was not affected. In the PAF-stimulated cytosolic Ca2+ increase, capsaicin inhibited in particular the sustained portion of the raised Ca2+ level without attenuation of the peak height. In the absence of extracellular Ca2+, the PAF-induced Ca2+ elevation was not inhibited by capsaicin because capsaicin only inhibited the Ca2+ influx from the extracellular space. In addition, capsaicin did not affect PAF-induced inositol 1,4,5-trisphosphate production, suggesting that phospholipase C activation by PAF is not affected by capsaicin. Store-operated Ca2+ entry (SOCE) induced by thapsigargin was inhibited by capsaicin in a concentration-dependent manner. This capsaicin effect was also observed on thapsigargin-induced Ba2+ and Mn2+ influx. Furthermore, capsaicin's inhibitory effect on the thapsigargin-induced Ca2+ rise overlapped with that of SK&F96365, an inhibitor of SOCE. Both capsaicin and SK&F96365 also inhibited PAF-induced cytosolic superoxide generation in HL-60 cells differentiated by all-trans-retinoic acid. Our data suggest that capsaicin exerts its anti-inflammatory effect by inhibiting SOCE elicited via PLC activation, which occurs upon PAF activation and results in the subsequent superoxide production.

Performance analysis of phase-code multiplexed holographic memory

For analysis of effective phase-code multiplexing in a holographic memory system four types of phase code are generated and used as a reference beam. In computer simulations the size of the address beam is fixed at 32 x 32 pixels, and 0%, 5%, 10%, 15%, 20%, and 25% phase-error rates in a pixel are purposely added to the real phase values for consideration of the nonlinear phase-modulation characteristics of a practical spatial light modulator. Cross talk and signal-to-noise ratios (SNR's) are comparatively analyzed for these phase codes by calculation of the autocorrelation and the cross correlation. The pseudorandom code (PSR) has the lowest cross-correlation mean value of 0.067 among the four types of phase code, which means that the SNR of the PSR is higher than with other phase codes. Also, the standard deviation of the PSR, indicating the degree of recalled data degradation, has the lowest value, at 0.0113.

Torsional rigidity of scoliosis constructs

STUDY DESIGN

A biomechanical study of the rigidity of various scoliosis constructs instrumented with and without caudal pedicle screw anchors and with none, one, or two cross-link devices.

OBJECTIVES

To determine whether the increased torsional rigidity provided by distal pedicle screw fixation might make cross-linking unnecessary.

SUMMARY OF BACKGROUND DATA

Pedicle screws and cross-linking devices have been shown to increase the structural rigidity of spinal constructs. Their relative contributions to scoliosis construct rigidity has not been determined.

METHODS

"Short" (T2-T11) and "long" (T2-L3) scoliosis constructs were mounted on an industrially fabricated spine model and tested in a hydraulic testing machine. Four different short and four different long constructs were tested: hooks only, hooks with concave side thoracic sublaminar wires, hooks with distal pedicle screw anchors, and hooks, distal pedicle screw anchors, and concave thoracic sublaminar wires. There were four iterations for each construct tested: no cross-links, one superior cross-link at T4-T5, one inferior cross-link at T9-T10, and two cross-links. Torsional rigidity was tested by applying a rotational torque at T2. Vertebral body motion was recorded with a three-dimensional video analysis system.

RESULTS

Constructs with distal pedicle screws were statistically more rigid in torsion than those with hooks as distal anchors. The additional torsional rigidity from one or more cross-links was negligible compared with that provided by pedicle screws.

CONCLUSIONS

With pedicle screws as distal anchors in scoliosis constructs, cross-linking with one or two devices adds very little additional rotational stiffness and may be unnecessary in many cases.

Differential stereoselectivity of D- and L-myo-inositol 1,2,4, 5-tetrakisphosphate binding to the inositol 1,4,5-trisphosphate receptor and 3-kinase

D- and L-myo-inositol 1,2,4,5-tetrakisphosphate (Ins(1,2,4,5)P(4)) were investigated for their ability to bind to the D-myo-inositol 1, 4,5-trisphosphate (Ins(1,4,5)P(3)) receptor in a bovine adrenal cortical membrane fraction, to mobilize intracellular Ca(2+) stores in Xenopus oocytes, and to bind to the rat brain Ins(1,4,5)P(3) 3-kinase overexpressed and purified in E. coli. In competitive binding experiments with the Ins(1,4,5)P(3) receptor, D-Ins(1,2,4, 5)P(4) effectively displaced [(3)H]Ins(1,4,5)P(3) in a concentration-dependent manner with a potency comparable to that of D-Ins(1,4,5)P(3), while L-Ins(1,2,4,5)P(4) was approximately 50-fold less effective than D-Ins(1,4,5)P(3) and D-Ins(1,2,4,5)P(4). The DL-Ins(1,2,4,5)P(4) racemate bound to the Ins(1,4,5)P(3) receptor with an apparent intermediate efficiency. Injection of D-Ins(1,2,4, 5)P(4) into oocytes evoked a chloride current dependent on intracellular Ca(2+) mobilization in which the agonists ranked in a similar order of potency as in the Ins(1,4,5)P(3) receptor binding. On the other hand, D-Ins(1,2,4,5)P(4) only inhibited the binding of [(3)H]Ins(1,4,5)P(3) to 3-kinase very weakly with a markedly reduced potency compared to D-Ins(1,4,5)P(3), indicating that D-Ins(1,2,4, 5)P(4) is not an effective competitor in the phosphorylation of [(3)H]-Ins(1,4,5)P(3) by 3-kinase. The results, therefore, clearly indicate that D-Ins(1,2,4,5)P(4) is as effective as D-Ins(1,4,5)P(3) in the binding to the receptor but not 3-kinase, and access of Ins(1, 2,4,5)P(4) over the Ins(1,4,5)P(3) receptor calls for stringent stereospecificity with D-Ins(1,2,4,5)P(4) being the active form in DL-Ins(1,2,4,5)P(4)-mediated Ca(2+) mobilization.

Primary peritoneal pregnancy implanted on the uterosacral ligament: a case report

Peritoneal pregnancies are classified as primary and secondary. Primary implantation on the peritoneum is extremely rare in extrauterine pregnancy and is a potentially life-threatening variation of ectopic pregnancy within the peritoneal cavity, representing a grave risk to maternal health. Secondary abdominal pregnancies are by far the most common and result from tubal abortion or rupture, or less often, after uterine rupture with subsequent implantation within abdomen. Early diagnosis and appropriate surgical management, regardless of stage of gestation, appear to be important in achieving good results. We report a case of primary peritoneal pregnancy in a 28-year-old woman, who had severe lower abdominal pain one day before laparotomy for a preoperative diagnosis of ectopic pregnancy. The conceptus was implanted on the left uterosacral ligament. A fresh embryo of approximately 8 weeks' gestation was found in the conceptus.

Nongenomic inhibition of catecholamine secretion by 17beta-estradiol in PC12 cells

We investigated the effects of 17beta-estradiol, an estrogen, on [(3)H]norepinephrine ([(3)H]NE) secretion in PC12 cells. Pretreatment with 17beta-estradiol reduced 70 mM K(+)-induced [(3)H]NE secretion in a concentration-dependent manner with a half-maximal inhibitory concentration (IC(50)) of 2 +/- 1 microM. The 70 mM K(+)-induced cytosolic free Ca(2+) concentration ([Ca(2+)](i)) rise was also reduced when the cells were treated with 17beta-estradiol (IC(50) = 15 +/- 2 microM). Studies with voltage-sensitive calcium channel (VSCC) antagonists such as nifedipine and omega-conotoxin GVIA revealed that both L- and N-type VSCCs were affected by 17beta-estradiol treatment. The 17beta-estradiol effect was not changed by pretreatment of the cells with actinomycin D and cycloheximide for 5 h. In addition, treatment with pertussis or cholera toxin did not affect the inhibitory effect of 17beta-estradiol. 17beta-Estradiol also inhibited the ATP-induced [(3)H]NE secretion and [Ca(2+)](i) rise. In PC12 cells, the ATP-induced [Ca(2+)](i) rise is known to occur through P2X(2) receptors, the P2Y(2)-mediated phospholipase C (PLC) pathway, and VSCCs. 17beta-Estradiol pretreatment during complete inhibition of the PLC pathway and VSCCs inhibited the ATP-induced [Ca(2+)](i) rise. Our results suggest that 17beta-estradiol inhibits catecholamine secretion by inhibiting L- and N-type Ca(2+) channels and P2X(2) receptors in a nongenomic manner.

A new method for aesthetic reduction of labia minora (the deepithelialized reduction of labioplasty)

An enlarged labium minus can be bothersome for functional, aesthetic, and social reasons. Labia minora hypertrophy can be congenital or acquired by chronic irritation, exogenous androgenic hormones, or stretching with weights. This can cause inflammation, poor hygiene, interference with sexual intercourse, or intermittent urinary self-catheterization in myelodysplastic women. Aesthetically, an asymmetric or enlarged labium minus causes self-consciousness sexually and when the subject wears tight pants. Previously, labia minora reduction was performed by amputation of the protuberant segment and oversewing the edge, or a wedge of protuberant labial tissue was excised and reapproximated. However, the former technique removes the natural contour and color of the edge of the labium minus, and the latter can result in an incomplete or tight reduction. Therefore, rather than an amputation or a wedge resection, we preserved the natural contour and anatomy of the labium minus by simply reducing its central width through bilateral deepithelialization and reapproximation of the central portion with preservation of the neurovascular supply to the edge. Six patients have undergone this reduction method with excellent results without specific complications.

Rapid and simple measurement of serotonin N-acetyltransferase activity by liquid biphasic diffusion assay

We report here a rapid, simple, and accurate method to assay for serotonin N-acetyltransferase (NAT) activity. This assay relies on the selective diffusion of radiolabeled acetyltryptamine into a water-immiscible scintillation fluid. Unlike organic solvent extraction, thin-layer chromatography, or high performance liquid chromatography, the separation of acetyltryptamine from acetyl CoA and tryptamine is not required in the method. Moreover, the limit of sensitivity is less than 4 pmol of N-acetyltryptamine formed per sample. Enhancement of NAT activity upon beta-adrenergic receptor stimulation in the rat pineal gland was clearly detected with this method. In addition, the NAT activity measurements obtained with this method agreed quantitatively in the pineal gland and other brain tissues with the conventional organic solvent extraction method. The results suggest that this liquid biphasic diffusion assay is applicable to the detection of NAT activity in tissues and cells.

Minimum prevalence of latex hypersensitivity in health care workers

Health care workers (HCW) have been shown to be at significant risk for developing latex allergy. Natural rubber latex hypersensitivity has been reported in 2.9 to 17% of health care workers in previously published studies. This study describes the prevalence of latex hypersensitivity in a large cohort of medical center employees. A screening questionnaire was distributed to 1967 employees in six job categories exposed to latex, and 1331 questionnaires were returned (68%) between March and November 1995. Skin and serologic testing was performed on 156 volunteers. Of the 1331 HCWs who completed the screening questionnaire, 290 (21.8%) self-reported contact dermatitis to latex, 67 (5.0%) self-reported urticaria to latex, 163 (12.2%) self-reported rhinoconjunctivitis to latex, and 17 (1.3%) self-reported asthmatic symptoms to latex. Of the total population of 1967 employees, 38 (1.9%) were either skin test or blood test positive and 30 (1.5%) of these 38 were symptomatic around latex. This study suggests a minimum prevalence of IgE-mediated hypersensitivity to latex of 1.5% among medical center employees. Our reported prevalence figures are lower than previously reported, reflecting, in part, reporting methods using a denominator more consistent with the total population at risk. Our study also illustrates the pitfall of relying on self-reporting in making the diagnosis of latex allergy.

B-myb proto-oncogene products interact in vivo with each other via the carboxy-terminal conserved region

Using the yeast two-hybrid assay and in vivo binding assay, we investigated whether B-myb oncogene products (B-myb) can associate with each other. Specificity tests of the yeast two-hybrid system showed a self-association of B-myb proteins in yeast. Cotransfection experiments demonstrated that B-myb proteins form a complex in vivo. Deletion analysis revealed that this binding was sufficiently mediated by the carboxy-terminal conserved region of B-myb. In addition, the B-myb self-association is directly dependent on the amount of expressed B-myb in cells and slightly increased by the dephosphorylation state. These results suggested that B-myb could form a complex and influence its transcriptional activity.

Capsaicin inhibits phospholipase C-mediated Ca(2+) increase by blocking thapsigargin-sensitive store-operated Ca(2+) entry in PC12 cells

Capsaicin has been shown to act through vanilloid receptors, which are temperature-sensitive cation channels. However, there also are indications that suggest the capsaicin effect is not mediated by the vanilloid receptor. We therefore investigated the effect of capsaicin on the phospholipase C-mediated Ca(2+) rise in PC12 cells. Capsaicin caused a rapid decline in extracellular ATP- or bradykinin-induced calcium transients to the basal level without significant attenuation of the peak level. However, capsaicin did not inhibit either ATP- or bradykinin-induced Ca(2+) elevation in the absence of extracellular Ca(2+) or inositol-1,4,5-trisphosphate production. Capsaicin also inhibited ATP-induced norepinephrine secretion. Capsaicin dramatically reduced the thapsigargin-induced sustained Ca(2+) level, suggesting that capsaicin inhibits thapsigargin-sensitive store-operated Ca(2+) entry (SOCE). Thapsigargin-induced Ba(2+) and Mn(2+) influx was also inhibited by capsaicin. Furthermore, capsaicin overlapped SK&F96365 in inhibiting thapsigargin-sensitive SOCE. Capsaicin-induced inhibition of SOCE also occurred in thapsigargin-treated Jurkat-T cells, which have a rather prominent SOCE. Resiniferatoxin, a vanilloid receptor agonist, did not mimic the effect of capsaicin. Ruthenium red and capsazepine, which are known to inhibit the vanilloid receptor, did not affect this capsaicin effect. The results suggest that capsaicin does not mediate vanilloid receptor signaling when inhibiting the thapsigargin-sensitive SOCE. The capsaicin action was also not mediated by activation of protein kinase C because phorbol-12-myristate 13-acetate and capsaicin did not overlap each other's effect and GF109203X did not reverse the inhibitory effect of capsaicin. The results suggest that capsaicin negatively modulates thapsigargin-sensitive SOCE subsequent to phospholipase C activation.

Chlorpromazine-induced inhibition of catecholamine secretion by a differential blockade of nicotinic receptors and L-type Ca2+ channels in rat pheochromocytoma cells

We investigated the effect of chlorpromazine (CPZ), a phenothiazine neuroleptic, on catecholamine secretion in rat pheochromocytoma (PC12) cells. CPZ inhibited [3H]norepinephrine ([3H]NE) secretion induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), an agonist of nicotinic acetylcholine receptors (nAChRs) with an IC50 value of 1.0 +/- 0.2 microM. The DMPP-induced rise in cytosolic free Ca2+ concentration [Ca2+]i was inhibited by CPZ with an IC50 of 1.9 +/- 0.1 microM. The DMPP-induced increase in cytosolic free Na+ concentration [Na+]i was also inhibited by CPZ with a similar potency. Furthermore, the binding of [3H]nicotine to PC12 cells was inhibited by CPZ with an IC50 value of 2.7 +/- 0.6 microM, suggesting that the nAChRs themselves are inhibited by CPZ. In addition, both 70 mM K+-induced [3H]NE secretion and [Ca2+]i increase were inhibited by CPZ with IC50 of 7.9 +/- 1.1 and 6.2 +/- 0.3 microM, respectively. Experiments with Ca2+ channel antagonists suggest that L-type Ca2+ channels are mainly responsible for the inhibition. We conclude that CPZ inhibits catecholamine secretion by blocking nAChRs and L-type Ca2+ channels, with the former being more sensitive to CPZ.

Phospholipase C-delta1 is activated by capacitative calcium entry that follows phospholipase C-beta activation upon bradykinin stimulation

To characterize the regulatory mechanism of phospholipase C-delta1 (PLC-delta1) in the bradykinin (BK) receptor-mediated signaling pathway, we used a clone of PC12 cells, which stably overexpress PLC-delta1 (PC12-D1). Stimulation with BK induced a significantly higher Ca(2+) elevation and inositol 1,4,5-trisphosphate (IP(3)) production with a much lower half-maximal effective concentration (EC(50)) of BK in PC12-D1 cells than in wild type (PC12-W) or vector-transfected (PC12-V) cells. However, BK-induced intracellular Ca(2+) release and IP(3) generation was similar between PC12-V and PC12-D1 cells in the absence of extracellular Ca(2+), suggesting that the availability of extracellular Ca(2+) is essential to the activation of PLC-delta1. When PC12-D1 cells were treated with agents that induce Ca(2+) influx, more IP(3) was produced, suggesting that the Ca(2+) entry induces IP(3) production in PC12-D1 cells. Furthermore, the additional IP(3) production after BK-induced capacitative calcium entry was detected in PC12-D1 cells, suggesting that PLC-delta1 is mainly activated by capacitative calcium entry. When cells were stimulated with BK in the presence of extracellular Ca(2+), [(3)H]norepinephrine secretion was much greater from PC12-D1 cells than from PC12-V cells. Our results suggest that PLC-delta1 is activated by capacitative calcium entry following the activation of PLC-beta, additively inducing IP(3) production and Ca(2+) rise in BK-stimulated PC12 cells.

Orbital floor and infraorbital rim reconstruction after total maxillectomy using a vascularized calvarial bone flap

A number of techniques have been introduced to support the orbital floor after maxillectomy without orbital exenteration. These methods include skin graft or muscular sling, but they have resulted in severe complications, such as enophthalmos, global ptosis, diplopia, and facial deformity. Currently, advanced microvascular reconstruction using bone and soft tissue is performed by many surgeons. This usually results in the filling of the postmaxillectomy defect, but the lack of support for the orbital rim and floor by the bone flap may still cause the complications mentioned above. Vascularized calvarial bone flap was chosen in this study for reconstruction of the orbital floor and infraorbital rim to function as a buttress, to reconstruct recipient sites of poor vascular bed after radiation therapy, and to withstand further postoperative radiation. By providing a solid floor and rim, these complications can be prevented with satisfactory function and aesthetically acceptable results. From September of 1995 to July of 1998, we performed vascularized bone flap for the reconstruction of the orbital floor and infraorbital rim in four cases after total maxillectomy involving the orbital floor. With a follow-up period from 19 to 35 months (mean, 27 months), we obtained significant improvement of functional and aesthetically acceptable results without global ptosis, enophthalmos, diplopia, or severe facial contour deformity.

Chronic pruritic papular dermatitis in adult men: a variant of prurigo

Chronic recurrent pruritic papular eruptions in which a specific diagnosis cannot be established becomes a baffling experience to the dermatologist. We have met adult male patients with chronic recurrent pruritic papular eruptions, but their clinicopathological features are not described in English language textbooks. Our purpose was to study the clinical and histological features of this entity and review the various existing taxonomy. We conducted a study of 20 patients over a six year period by taking histories, performing skin biopsies, screening patch tests, and doing immunofluoresence studies. The eruptions occurred exclusively in male adults and had a predilection for the trunk and proximal extremities. The lesions were characterized by severely pruritic, nonfollicular, monomorphic, erythematous urticarial papules. There was no evidence of atopic diathesis or history of insect bite. Most patients had normal levels of serum eosinophils and IgE. The predominant histopathologic finding was a presence of perivascular infiltration of mononuclear cells with eosinophils. The patients followed a chronic course of at least six months with waxing and waning; systemic corticosteroids were the only effective treatment. Finally, all other pruritic erythematous papular dermatoses were ruled out. These cases comprise a distinct entity that has previously been mentioned in a few reports. Clear definition of this entity with an appropriate designation is in order to avoid confusion among dermatologists, and we propose the disease name "chronic papular dermatitis in adult men" as a variant of prurigo.

Update on the status of Africanized honey bees in the western states

The Africanized honey bee (AHB), Apis mellifera scutella--perhaps better known as the "killer bee"--has arrived in the western United States and in southern California, following a nearly 50-year north-ward migration across South and Central America. First detected near Hidalgo, Texas in October 1993, the bees continue to advance 100 to 300 miles per year by colonizing existing hives or forming new hives in the wild. Although the AHB's "killer" reputation has been greatly exaggerated, the presence of AHBs will increase the chances of people being stung.