Cholelithiasis prevalence and risk factors in individuals with severe or profound intellectual and motor disabilities

BACKGROUND

The prevalence and risk factors of cholelithiasis in individuals with severe or profound intellectual and motor disabilities (SPIMD) are poorly characterised. Thus, we aimed to investigate the prevalence and risk determinants of cholelithiasis in a cohort with SPIMD under medical care in a residential facility.

METHODS

We categorised 84 patients in a residential hospital for persons with SPIMD into groups: those with (Group CL) and without (Group N) cholelithiasis. Gallstones were detected via computed tomography, ultrasonography or both. We evaluated gastrostomy status, nutritional and respiratory support, constipation, and bladder and kidney stones. Data were significantly analysed using univariate and multivariate logistic regression analyses.

RESULTS

The prevalence rate of cholelithiasis in our SPIMD cohort was 27%. There were no significant differences in sex, age, weight, height, or Gross Motor Function Classification System between the two groups. However, more patients received enteral nutrition (39.13% vs. 6.56%; P = 0.000751) and were on ventilator support (56.52% vs. 19.67%; P = 0.00249) in Group CL than in Group N. Enteral nutrition [odds ratio (OR) 10.4, 95% confidence interval (CI) 1.98-54.7] and ventilator support (OR 20.0, 95% CI 1.99-201.0) were identified as independent risk factors for the prevalence of cholelithiasis in patients with SPIMD.

CONCLUSIONS

Patients with SPIMD demonstrated an increased prevalence of cholelithiasis, with a notable association between nutritional tonic use and respiratory support. Therefore, to emphasise the need for proactive screening, it is crucial to devise diagnostic and therapeutic strategies specific to patients with SPIMD. Further investigation is essential to validate our findings and explore causative factors.

A Case of Closed Pilon Fracture Resulting in Soft-Tissue Necrosis and Treated with Reverse Sural Artery Flap and Circular External Fixation

Tibial pilon fractures are difficult to treat due to articular comminution and soft-tissue injuries caused by high-energy trauma. Open reduction and internal fixation is a commonly used method of treatment. However, it has a high risk of infection and soft-tissue complications due to the extensive detachment of soft tissue. We report on a case with a tibial pilon fracture and soft-tissue necrosis that we treated using limited internal fixation combined with a circular external fixator (LIFCEF) and reverse sural artery flap (RSAF) as part of an orthoplastic approach within the orthopedic surgery department alone, which obtained good results. A 51-year-old man was injured in a motorcycle accident and transported to a nearby hospital. X-rays at the time of injury showed tibial pilon fractures (AO Foundation/Orthopedic Trauma Association 43c3.3, Ruedi-Allgower: Type III). Soft-tissue necrosis with blisters on the medial side of the lower leg (AO soft-tissue classification: IC3-MT1-NV1) was observed. In addition, the patient was referred to our hospital on day 10 of the injury. LIFCEF was chosen for treating the fracture because plate fixation was accompanied by the risk of plate exposure, soft-tissue complications, and an increased skin defect area, and RSAF was chosen to reconstruct the soft tissue defect. Four years after the surgery, the American Orthopedic Foot and Ankle Score was 92 points. X-ray alignment evaluation showed mLDTA 93° and aADTA 91°. Stage 2 arthrosis was present according to the Takakura ankle osteoarthritis classification, but the patient was able to walk without pain. Tibial pilon fractures are difficult to treat due to articular comminution and soft-tissue injuries caused by high-energy trauma. The timing and choice of treatment are crucial concerning the soft tissue.

The impact of right atrium and left atrium reverse remodeling for functional regurgitation of atrioventricular valve among patients who were underwent ablation for atrial fibrillation

Background

Atrial fibrillation (AF) is a risk factor of Regurgitation of Atrioventricular Valve and Regurgitation of Atrioventricular Valve is improved after ablation for AF. However, Mechanism of improvement of Tricuspid regurgitation (TR) and Mitral regurgitation (MR) after ablation for AF were unclear.

Methods

The one hundred fifty-seven cases consecutive patients who were underwent ablation for persistent AF were examined in this study. These patients were performed Holter ECG and Echocardiography 6 months after ablation for persistent AF. The area of the Right Atrium (RA), Left Atrium (LA), diameter of the tricuspid valve anulus and Mitral valve annulus, were measured by echocardiography at before and 6 months after ablation for AF. The reverse remodeling index (RRI) was defined as divided post area of RA and LA by pre area of RA and LA. The Improved group was defined as one or more than regurgitation grade improvements.

Results

TR improved in 56 cases (35.7%) of 157 cases and MR improved in 25 (16.6%) cases of 157 cases. The ratio of improved TR was significantly higher than ratio of improved MR (p<0.01). The difference in tricuspid annulus diameter before and after ablation for AF was significantly longer in TR improved group than in TR non-improved group. (4.9±5.3 mm vs 1.6±5.4 mm, p<0.01). The RRI of RA in TR improved group was significantly smaller than in TR non-improved group (0.73±0.19 vs 0.89±0.26 p<0.01). The difference in mitral annulus diameter before and after ablation for AF was not significant differences between MR improved group and MR non-improved group. The RRI of LA in MR improved group was significantly smaller than in MR non-improved group (0.79±0.22 vs 0.90±0.25 p<0.01). The RRI of RA was significantly smaller than RRI of LA among patients who were able to maintain sinus rhythm after ablation for persistent AF (0.79±0.23 vs 0.85±0.24 p=0.04).

Conclusion

Reverse remodeling of RA was higher than Reverse remodeling of LA among patients who were able to maintain sinus rhythm after ablation for persistent AF and Reverse remodeling of RA and LA were important factors of improvement of TR and MR after ablation for persistent AF. These results considered to be the cause why the improvement rate of TR was higher than the Improvement rate of MR after persistent AF.

Funding Acknowledgement

Type of funding sources: None.

Nail insertion points in semi-extended nailing of tibial fractures and their influence on alignment: A retrospective cohort study comparing two nail insertion techniques

INTRODUCTION

Semi-extended tibial nailing techniques include the extra-articular technique (EAT) and the patellar eversion technique (PET). These approaches differ regarding the exposure of the patellar retinaculum and the size of the surgical field. This study compared the postoperative alignment and intramedullary nailing entry points between the EAT and PET for tibial fractures.

PATIENTS AND METHODS

A total of 54 patients (aged ≥18 years) who had undergone intramedullary nailing by the EAT (n = 29) or PET (n = 25) for a tibial shaft fracture were evaluated. The intramedullary nailing entry point and postoperative alignment were measured, and the 1-year postoperative follow-up results were compared.

RESULTS

For the EAT and PET, the intramedullary nailing entry point was located at a mean distance of 4.04 mm medial to the optimal entry point and 0.27 mm lateral to the optimal entry point, respectively. The mean angular deformation observed in anteroposterior radiographs following surgery using the EAT and PET were 2.49° and 0.32° valgus, respectively.

CONCLUSION

The intramedullary nailing entry point affected postoperative alignment. Intramedullary nailing may result in malalignment while performing the EAT due to the interference of the patella at the time of nailing.

[Concurrent chemoradiation therapy with nedaplatin for high-risk cervical cancer--clinical investigation of adverse events]

A clinical investigation of adverse events was conducted to confirm the safety of concurrent chemotherapy using nedaplatin (cisplatin derivative) and radiotherapy in the high-risk carcinoma of the uterine cervix. Seven patients who were treated with radical radiotherapy and 5 patients who were treated with adjunctive radiotherapy after radical hysterectomy and pelvic lymphadenectomy were eligible for the study. Nedaplatin was given intravenously at 70 mg/m2 on day 1 and day 29, and a total of 24 courses of nedaplatin administration were observed. None of the planned radiotherapy was postponed or discontinued due to side effects. Major adverse effects observed were gastrointestinal effects such as anorexia (66.7%), nausea and vomiting (33.3%) and diarrhea (66.7%). Grade 3 (in the 2nd course) and Grade 4 (in the 1st course) diarrhea was observed in one patient, which was easily relieved by antidiarrheal. Hematologic side effects were also major, including leukopenia (62.5%), neutropenia (75.0%), anemia (75.0%), and thrombocytopenia (33.3%). Hematologic effects were generally moderate; no Grade 4 (severe) effects were observed. Although these hematologic effects were lasting longer compared with radiation therapy alone, there were no significant differences in the seriousness of these side effects. Concurrent chemoradiation therapy with nedaplatin 70 mg/m2 every 4 weeks was safe and adverse effects were self-limited or resolved with medical management. Dose escalation in the phase III clinical study may be considered.

Transient thyrotoxicosis and hypothyroidism following administration of the GnRH agonist leuprolide acetate

A 45-year-old women with chronic idiopathic thrombocytopenic purpura was given monthly injections of the GnRH agonist leuprolide acetate for the treatment of uterine leiomyoma. Two weeks after the fifth injection, she showed mild symptoms of thyrotoxicosis. At that time, serum thyroxin (T4) and triiodothyronine (T3) levels were elevated whereas TSH level was suppressed. Anti-thyroglobulin (anti-Tg) and anti-thyroid peroxidase (anti-TPO) antibodies were positive, whereas TSH binding inhibitory immunoglobulin (TBII) was undetectable. Two months later, serum T4 and T3 levels spontaneously decreased below the normal ranges. Five months after the onset of the disease, they returned to normal without any treatment. Anti-TPO and anti-Tg antibodies gradually decreased during the clinical course. Thus, the present case was indicated to be an instance wherein silent thyroiditis developed after leuprolide acetate administration. This is the first report to demonstrate the association of thyroid disorder with leuprolide injection.

Structure-activity studies of analogues of blomhotin mediating contraction of rat fundus

Blomhotin is a novel peptide (pGlu1-Gly2-Arg3-Pro4-Pro5-Gly6-Pro7-Pro8-Ile9-Pro10-Arg11) which has been isolated from the venom of Agkistrodon halys blomhoffii and exhibits contractile activity on rat stomach fundus. We carried out a structure-activity study of blomhotin and its related peptides, and the findings suggested that the N-terminal portion of blomhotin is mainly responsible for affinity for the blomhotin receptor, whereas the C-terminal portion of blomhotin, Pro-Ile-Pro-Arg, is responsible for complete activation of the blomhotin receptor in the rat stomach fundus. In particular, the amino acids at positions 9 and 11 of blomhotin appear to be essential for binding and intrinsic activity. Using knowledge gained from this structure-activity analysis, we have identified photoactive blomhotin analogues that have sufficient biological activity to probe the target molecule of blomhotin.

[Vascular anastomoses in free jejunal reconstruction to the neck vessels: an experience of consecutive 20 cases without using surgical microscope]

Twenty consecutive cases of pharyngoesophageal cancer who underwent free jejunal reconstruction were reported. The common carotid or external carotid artery was used for a feeder of the free graft. The internal jugular vein were served as a drainage vein. All anastomoses were performed in an end-to-side fashion without using surgical microscopes. Mean carotid artery clamping time was 16 minutes and no neurological complications were noticed postoperatively. Graft failure was occurred in 1 patient. The presenting technique, showing 95% success rate, is recommended as a simple option for vascular anastomosis in free jejunal reconstructive surgery.

cDNA cloning of bradykinin-potentiating peptides-C-type natriuretic peptide precursor, and characterization of the novel peptide Leu3-blomhotin from the venom of Agkistrodon blomhoffi

A cDNA clone, 1.8 kb long, was isolated from a venom gland cDNA library of Agkistrodon blomhoffi that encodes a large plurifunctional precursor composed of 263 amino-acid residues. Nucleotide sequence analysis of this clone revealed that sequences which code for blomhotin and a novel peptide Leu3-blomhotin are located in the N-terminal region of the precursor polypeptide, followed by four tandemly aligned sequences which code for three types of bradykinin-potentiating peptide. In the C-terminal region, the sequence for the C-type natriuretic peptide was located along with a preceding processing signal. The deduced amino-acid sequences for the four bradykinin-potentiating peptides coincided exactly with previously known sequences for potentiator B, potentiator C and potentiator E. The actual Leu3-blomhotin peptide was subsequently isolated from the venom of A. blomhoffi and characterized. Leu3-blomhotin possesses contractile activity in isolated rat stomach fundus smooth muscle in the same manner as blomhotin. Furthermore, it was shown that blomhotin and Leu3-blomhotin retained activity to inhibit the angiotensin-converting enzyme.

Cytokine production in chorioamnionitis

Lymphohematopoietic cytokines play a significant role in many biological mechanisms including a number of reproductive processes such as ovulation, implantation, placentation, cervical dilation and parturition. Recent experiments have suggested that cytokines play a crucial role in the mechanisms of preterm labor and delivery, which are the leading causes of perinatal morbidity and mortality. Growing evidence suggests that infection is deeply concerned in the pathogenesis of preterm labor and delivery. Chorioamnionitis, a subset of intrauterine infection, has been identified in 20-33% of women with preterm delivery, and the inflammatory and related cytokines, interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8), showed substantial increases in the amniotic fluid at women with intrauterine infection. Although the precise mechanism for chorioamnionitis-driven preterm labor mediated via cytokines is still unknown, both IL-1 and TNF-alpha along with IL-6 enhance prostaglandin production by human amnion cells, chorionic cells and decidual cells. Analysis of the regulatory sequences in the 5' upstream regions of receptor gene for human oxytocin, a potent uterotonic agent, suggests a close relationship between preterm labor and inflammatory cytokines through induction at the oxytocin receptor. Prompt identification of the patients with intra-amniotic infection may be useful in clinical practice. At present, the measurement of IL-8 in maternal serum or the measurement of IL-6 in cervical secretion may be helpful as a non-invasive screening for chorioamnionitis.

Amino acid sequence studies on cytolytic toxins from sea anemone Heteractis magnifica, Entacmaea quadricolor and Stichodactyla mertensii (Anthozoa)

The complete amino acid sequence of a cytolytic toxin, HmT, isolated from sea anemone Heteractis magnifica was determined. It is composed of 177 amino acid residues and lacks half-cystines. Partial N-terminal sequences of three other cytolysins from Entacmaea quadricolor (EnT) and Stichodactyla mertensii (SmT-1 and SmT-2) were also determined. Comparing these sequences with those of other sea anemone cytolysins, a high degree of homology was observed.

Blomhotin: a novel peptide with smooth muscle contractile activity identified in the venom of Agkistrodon halys blomhoffii

A novel peptide has been isolated from the venom of Agkistrodon halys blomhoffii using a bioassay that monitors the stimulant effect on rat stomach fundus. The 11-amino acid peptide, named blomhotin, was purified to homogeneity by gel-filtration column chromatography and reverse-phase HPLC. The amino acid sequence of blomhotin was determined to be pGlu-Gly-Arg-Pro-Pro-Gly-Pro-Pro-Ile-Pro-Arg, which is similar to that of bradykinin-potentiating peptides which themselves cause no contraction of smooth muscle. The contraction induced by blomhotin showed homologous desensitization, implicating the involvement of a blomhotin-specific site in the response.

Satisfaction of patients treated surgically for intractable aspiration

STUDY OBJECTIVE

Impaired laryngeal protective function can result in intractable aspiration requiring surgical treatment. There are, however, few reports evaluating the satisfaction of patients and the efficacy of surgical therapy. The purpose of this study is to determine whether surgery for intractable aspiration is beneficial for alleviating depression and improving the mood of patients who have undergone surgical treatment and whether patients and their families are satisfied with the therapy.

PATIENTS AND STUDY DESIGN

Seven patients with recurrent aspiration pneumonia that could not be controlled by appropriate medical therapies participated in the study. These patients had no hope of recovering laryngeal function. Six underwent laryngectomy and one underwent laryngotracheal separation. After surgery, we evaluated the efficacy of the therapy and the patients' satisfaction with the therapy.

METHODS

The following clinical variables concerning surgical procedure were examined: operation time, time until oral intake, videofluorographic study, and surgical complications. The treatment methods including feeding status were also examined before and after surgery. In addition, the following markers were examined to evaluate the efficacy of the surgery: score of aspiration pneumonia, body mass index, total protein, albumin, hematocrit, WBC count, C-reactive protein, erythrocyte sedimentation rate, and the Barthel Index, an indicator of daily activity. Furthermore, the grade of depression and mood, and satisfaction of patients and their caretakers among family members were scored by the Zung self-rating depression scale, a 20-picture face scale, and the visual analog scale.

RESULTS

After surgical therapy, we confirmed by videofluorography that aspiration was completely prevented. No surgical complications occurred. By 18 +/- 6 days, all seven patients were able to ingest a meal orally. The need for extensive medical care and repeated hospitalizations became unnecessary after surgery. The control of pneumonia and albumin improved significantly. The grade of depression and mood of patients and their families also improved significantly. Satisfaction scores of patients receiving therapy were very high.

CONCLUSIONS

Our study shows that surgical therapy to prevent aspiration improves the depression and mood of patients and their families as well as feeding status and clinical outlook. Surgical therapy for patients with intractable aspiration is effective and beneficial.

Inhibition of lysoPAF acetyltransferase activity by components of licorice root

Licorice root traditionally used as an anti-inflammatory drug exhibited an inhibitory effect on lysoPAF (platelet-activating factor) acetyltransferase in vitro: the ether soluble fraction of the crude drug produced a 27.3% inhibition at a concentration 10 microg/ml. From this fraction, licoricidin (1), 1-methoxyphaseollin (2), 6,8-diprenylgenistein (3) and 1-methoxyphaseollidin (4) were isolated as active components, whose IC50 values were 7.7, 57, 19 and 48 microM, respectively. Licoricidin (1) seems to be one of the most potent compounds of plant origin isolated so far.

Effects of PAF on histamine H1 receptor mRNA expression in rat trigeminal ganglia

The application of platelet-activating factor (PAF) to the nasal mucosa of humans has been shown to increase histamine-induced hyper-reactivity. To test the hypothesis that PAF acts by increasing the reactivity of sensory nerve endings in the nasal mucosa to histamine, we examined PAF-stimulated rat trigeminal nerve ganglion cells. We found that relatively low concentrations of PAF (10(-12)-10(-9) M) induced increased histamine H1 receptor mRNA expression. This increase appeared as early as 1 h after PAF stimulation, peaked at 4 h, and disappeared after 24 h. The PAF receptor antagonist WEB2086 inhibited the increased expression of histamine H1 receptor mRNA induced by PAF, suggesting that the effects of PAF are mediated by specific receptors. This PAF effect was abolished by actinomycin D, suggesting that PAF induces de novo transcription of histamine H1 and/or PAF receptor mRNA. PAF may be important in the hyper-responsiveness of nasal mucosa exposed to histamine.

Dynamics of immunoglobulins at the feto-maternal interface

Transplacental transport of maternal immunoglobulin G (IgG) to the developing fetus is extremely important in the protection of the newborn from infection. Although the exact mechanisms of the selective and active transfer of IgG across the placental barrier are not fully understood, receptors for the Fc part of IgG (FcgammaRs) in the placenta are believed to play a key role. Several known Fc receptors, FcgammaRI, FcgammaRII, FcgammaRIII and FcRn (neonatal FcR), demonstrate heterogeneous expression patterns in placenta. Immunohistochemical analysis shows the expression of FcgammaRI on Hofbauer cells in stromal tissue, FcbetaRII on Hofbauer cells and fetal blood endothelium, FcgammaRIII on Hofbauer cells and trophoblasts, and FcRn on syncytiotrophoblasts and endothelial cells. Recent studies provide evidence for important associations among these receptors and transcytosis of IgG, as well as scavenger mechanisms for clearing immune complexes in the placenta during pregnancy.

Suicide gene therapy for human uterine adenocarcinoma cells using herpes simplex virus thymidine kinase

In gene therapy, the herpes simplex virus thymidine kinase (HSV-tk) gene is widely used as a suicide agent. Tumor cells expressing HSV-tk are sensitive to nucleoside analogs such as ganciclovir (GCV). An advantage of this system is the bystander killing effect whereby HSV-tk-positive cells exposed to GCV are lethal to surrounding HSV-tk-negative cells. We transfected the HSV-tk gene into a human cervical adenocarcinoma cell line, BU25TK-, and a human endometrial adenocarcinoma cell line, HHUA, by the Lipofectine method. The sensitivity of HSV-tk-positive cells to GCV and bystander killing effect on HSV-tk-negative cells were examined in vitro. HSV-tk-positive cells were sensitive to GCV at concentrations of 1 to 100 microg/ml in a dose- and time-dependent manner. The growth of HSV-tk-negative cells was inhibited when the population of cultured cells contained more than about 3% HSV-tk-positive cells. Moreover, for BU25TK- cells, HSV-tk-positive cells were injected into SCID mice subcutaneously and the effects of GCV therapy and bystander killing at a daily concentration of 25 mg/kg for 14 days were examined. HSV-tk-positive tumors transduced into SCID mice almost disappeared upon GCV treatment. Furthermore, tumor reduction was observed when mixtures of HSV-tk-negative cells containing more than 20% HSV-tk-positive cells were injected into SCID mice. In conclusion, the HSV-tk/GCV system might be applied to both cervical and endometrial adenocarcinoma.

cAMP stimulates the bystander effect in suicide gene therapy of human choriocarcinoma

In gene therapy, tumor cells expressing herpes simplex virus thymidine kinase (HSV-tk) are sensitive to ganciclovir (GCV) and HSV-tk positive cells exposed to GCV are lethal to adjacent HSV-tk negative cells. This phenomenon has been called the bystander effect, and the gap junction is thought to mediate it. In this study, sensitivity to GCV and bystander effect in a human choriocarcinoma cell line, BeWo, transfected with HSV-tk were investigated. Furthermore, the effect of 8-bromo-cAMP on bystander effect and connexin40 gene transcription were examined. HSV-tk positive cells were sensitive to GCV at the concentration of 10 micrograms/ml in a time-dependent manner. The growth of HSV-tk negative cells was inhibited when the population of cultured cells contained more than 10% HSV-tk positive cells and 8-bromo-cAMP enhanced bystander effect. 8-bromo- cAMP increased connexin40 mRNA expression and gap junctional intercellular communication.

Modulation of normal human eosinophil chemotaxis in vitro by herbimycin A, erbstatin and pervanadate

BACKGROUND

The mediators involved in eosinophil accumulation in diseases such as allergy continue to be an area of interest, even though little is known regarding the signaling involved in the human cell type recruitment. In the present study, we demonstrate a novel modulatory role of tyrosine kinase and tyrosine phosphatase activities on normal human eosinophil chemotaxis induced by different groups of chemoattractant.

METHODS

Purified eosinophils were obtained from normal healthy volunteers with the CD16-negative procedure. Chemotactic activities against platelet-activating factor (PAF), vasoactive intestinal peptide (VIP) and eotaxin were assessed using a 48-well microchemotaxis chamber assay. Purified eosinophils were pretreated with herbimycin A, erbastatin or pervanadate to examine the role of tyrosine kinase in chemoattractant signaling.

RESULTS

Pretreatment of eosinophils with the tyrosine kinase inhibitors herbimycin A and erbstatin significantly blocked chemotaxis induced by eotaxin whilst both inhibitors augmented chemotaxis induced by VIP; however, they had no effect on PAF-induced chemotaxis. On the other hand, pretreatment of eosinophils with the phosphotyrosine phosphatase inhibitor pervanadate resulted in augmentation of eotaxin-induced chemotaxis and inhibition of VIP-induced chemotaxis, but it had no effect on PAF-induced chemotaxis.

CONCLUSIONS

These results suggest that protein kinase plays a modulatory role in eosinophil chemotaxis induced by various chemoattractants.

Human eotaxin induces eosinophil-derived neurotoxin release from normal human eosinophils

BACKGROUND

Eosinophil granule proteins deposition at the site of allergic inflammation contributes to the late-phase reaction of hypersensitivity diseases. In the present communication, we describe the effect of human eotaxin on normal human eosinophil exocytosis measured as degranulation of eosinophil-derived neurotoxin (EDN).

METHODS

Purified eosinophils were obtained from normal healthy volunteers with the CD16-negative procedure. Purified eosinophils were stimulated with various concentrations of eotaxin and the amount of EDN released was analysed by radioimmunoassay. Flow cytometry was used to examine the surface expression of adhesion molecules on eosinophils.

RESULTS

Eotaxin significantly induced EDN release in a dose-dependent manner. The potency of eotaxin in this effect was equal to that of RANTES, and comparable to that of platelet-activating factor. Eotaxin-induced EDN release was blocked by cytochalasin B in a dose-dependent manner. The surface expression of CD11a, CD11b, CD18 and VLA-4 adhesion molecules on normal human eosinophils were not modulated by eotaxin stimulation.

CONCLUSIONS

These results indicate that eotaxin may play an important role not only as a selective chemotaxin for the cell type but also as a secretagogue. Furthermore, they demonstrate a degranulation mechanism(s) involving cytoskeletal changes which is probably independent of the quantitative expression of adhesion molecules.

PAF- and histamine-receptor antagonists lessen allergen-induced hearing impairment in guinea pigs

We have demonstrated degranulation of mast cells in the endolymphatic sac as well as an increase in audiological threshold shift in the experimental animal models following antigen provocation. Mast cells, however, release such chemical mediators as histamine, platelet activating factor (PAF), and leukotriene due to an antigen-antibody reaction on the cell surface. The aim of this study was to clarify the major chemical mediators responsible for hearing impairment in the animal models following antigen provocation. Guinea pigs were actively sensitized with DNP-Ascaris and provoked with an injection of DNP-BSA. A significant audiological threshold shift was observed at 1, 10, 24, and 72 h following challenge with allergen. The peak shift was at 10 h; all changes were reversed after 7 days. This threshold shift was abolished by prior injection of either a histamine- or PAF-receptor antagonist to allergen, but not of a leukotriene-receptor antagonist. Results suggest that histamine and PAF are involved in the hearing impairment induced by allergen exposure in the guinea pig.

Activated mast cells release extracellular type platelet-activating factor acetylhydrolase that contributes to autocrine inactivation of platelet-activating factor

IgE-dependent and -independent activation of mouse bone marrow-derived mast cells (BMMC) elicited rapid and transient production of platelet-activating factor (PAF), which reached a maximal level by 2-5 min and was then degraded rapidly, returning to base-line levels by 10-20 min. Inactivation of PAF was preceded by the release of PAF acetylhydrolase (PAF-AH) activity, which reached a plateau by 3-5 min and paralleled the release of beta-hexosaminidase, a marker of mast cell exocytosis. Immunochemical and molecular biological studies revealed that the PAF-AH released from activated mast cells was identical to the plasma-type isoform. In support of the autocrine action of exocytosed PAF-AH, adding exogenous recombinant plasma-type PAF-AH markedly reduced PAF accumulation in activated BMMC. Furthermore, culture of BMMC with a combination of c-kit ligand, interleukin-1beta and interleukin-10 for > 24 h led to an increase in plasma-type PAF-AH expression, accompanied by a reduction in stimulus-initiated PAF production. Collectively, these results suggest that plasma-type PAF-AH released from activated mast cells sequesters proinflammatory PAF produced by these cells, thereby revealing an intriguing anti-inflammatory aspect of mast cells.

Preferential infiltration by activated eosinophils in allergic sinusitis

Although Type I allergy is a trigger for provoking chronic inflammation, whether allergic sinusitis (AS) can be distinguished from sinusitis due to chronic infection is still debated. This study was performed to characterize inflammatory cells in AS and to determine whether patients with AS differ from patients with chronic suppurative sinusitis (CSS). 5 patients with AS and 10 patients with CSS were investigated. Cellular infiltration was studied using immunohistochemistry with monoclonal antibodies using CD3, CD4, CD8, CD25, major basic protein (BMK13), eosinophil cationic protein (EG2), neutrophil elastase, and tryptase. There were no differences in CD3+, CD4+, CD25+, and tryptase+ cells between the groups. Whereas the total number of eosinophils (BMK13+) also did not significantly differ, the number of activated eosinophils (EG2+) was significantly higher (P < 0.05) in patients with AS. Furthermore, a statistically significant increase in the percentage of activated eosinophils to total eosinophils (P < 0.05) was observed in patients with AS. In contrast, the number of neutrophil elastase+ cells was significantly higher (P < 0.05) in patients with CSS. These results suggest that patients with AS can be distinguished immunohistochemically from patients with CSS, with AS being distinguished by activated eosinophil infiltration.

Specificity of two types of phospholipase A2 inhibitors from the plasma of venomous snakes

Specificity of two different types of phospholipase A2 (PLA2) inhibitory proteins from the blood plasma of venomous snakes was investigated. Two Crotalidae inhibitors, having a carbohydrate recognition domain (CRD) in their sequences, inhibited specifically the group-II acidic PLA2s of their own snake venom. On the other hand, Elapidae inhibitor, having two tandem patterns of cysteine residues found in proteins of the Ly-6 superfamily, inhibited not only the group-I PLA2 from its own snake venom but also the group-I, -II, and -III PLA2s from other snake venom. Amino acid sequences of PLA2s that were specifically inhibited by the inhibitors were compared with those of the other PLA2s. A unique aromatic patch structure appeared on the group-II acidic PLA2s was suggested to be involved in the binding to the Crotalidae inhibitors; and residues located in or close to the Ca2+ binding loop of PLA2, in the binding to the Elapidae inhibitor.

Lactoferrin as a suppressor of cell migration of gastrointestinal cell lines

The effects of lactoferrin (Lf), an iron-binding glycoprotein, on cell migration were investigated. Lf inhibited the cell migration of three gastrointestinal cell lines (Caco-2 cells, AGS cells, and IEC-18 cells) in vitro. Both iron-saturated (holo) and iron-depleted (apo) Lf showed this inhibitory effect. Chelation of iron in the culture medium by desferrioxamine did not affect the activity of either form of Lf. A pepsin hydrolysate of Lf exhibited effectiveness similar to that of intact Lf. These results demonstrate a novel activity of Lf and suggest a potential role for this molecule in gastrointestinal wound healing, which is independent of its iron-binding capacity.

Amino acid sequence of two neurotoxins from the venom of the Egyptian black snake (Walterinnesia aegyptia)

The venom of the Egyptian black snake Walterinnesia aegyptia contains at least three toxins, which act postsynaptically to block the neuromuscular transmission of isolated rat phrenic nerve-diaphragm and chicken biventer cervicis muscle. The complete amino acid sequence of the two toxins, W-III and W-IV, consisting of 62 amino acid residues, was elucidated by Edman degradation of fragments obtained after Staphylococcus aureus protease and prolylpeptidase digestion. Although the toxins exhibit close structural homology to other short-chain postsynaptic neurotoxins from Elapidae venoms, toxin IV is unique by having a free SH-group (cysteine) at position 16. In position 35 of W-III, which is located at the tip of the central loop, threonine is replaced by lysine, which may alter the interaction of the toxin with the acetylcholine receptor, since the toxin is seven times less lethal than toxin W-IV.

The novel role of 3',5'-guanosine monophosphate (cGMP) on the differentiation of trophoblasts: comparison with the effects of 3',5'-adenosine monophosphate (cAMP)

We investigated the effects of 3',5'-guanosine monophosphate (cGMP) on the differentiation of human trophoblasts. Isolated cytotrophoblasts were cultured with 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) or 8-bromoadenosine 3'5-cyclic monophosphate (8-Br-cAMP) and then stained immunocytochemically with anti-human chorionic gonadotropin (anti-hCG) antibody to identify hCG expression as an index of differentiation. Concurrently, morphological changes from cytotrophoblasts to syncytiotrophoblasts were analyzed. Both 8-Br-cGMP and 8-Br-cAMP enhanced the expression of hCG in cultured cytotrophoblasts with the differentiation of cytotrophoblasts to syncytiotrophoblasts dose-dependently. With regard to trophoblast proliferation, 8-Br-cAMP but not 8-Br-cGMP enhanced [3H]thymidine uptake by these cells. hCG, a trophoblast-specific glycoprotein hormone has been identified as a potent growth factor for trophoblasts, also increased [3H]thymidine uptake and the intracellular 3',5'-adenosine monophosphate (cAMP) concentration. However, in this study, hCG did not increase the concentration of intracellular cGMP. We also showed that sodium nitroprusside (SNP), which is a donor of nitric oxide (NO), enhanced intracellular cGMP concentration. These results suggest that cGMP enhances trophoblast differentiation without affecting their proliferation, while cAMP enhances both differentiation and proliferation. We conclude that an alternative pathway mediated through cGMP is responsible for the differentiation of trophoblasts. NO may be involved in trophoblast differentiation with an increase in cellular cGMP level.

Inhibition of lysoPAF acetyltransferase activity by flavonoids

OBJECTIVE AND DESIGN

Several kinds of flavonoids, widely distributed natural products of the vegetable kingdom which possess anti-inflammatory activity, were examined for inhibitory effects on the acetyl-CoA: 1-alkyl-2-lyso-sn-glycero-3-phosphocholine (lysoPAF) acetyltransferase activity.

METHODS

Acetyl-CoA:lysoPAF acetyltransferase activity was determined using homogenates of a rat mucosal-type mastocytoma cell line, RBL-2H3 as an enzyme source. The production of platelet-activating factor (PAF) in rat peripheral white blood cells stimulated with the calcium ionophore A23187 was studied.

RESULTS

Of the flavonoids tested, luteolin and quercetin exhibited significant inhibitory effects (IC50, 45 microM and 80 microM, respectively), whereas other structurally-related flavonoids failed to affect the lysoPAF acetyltransferase activity. Luteolin did not suppress the activity of choline acetyltransferase, suggesting that the inhibition observed here was specific. Luteolin also inhibited the production of PAF in rat peripheral white blood cells.

CONCLUSIONS

These results indicate that luteolin could become a leading compound for developing a novel type of anti-inflammatory, anti-allergic drugs that target lysoPAF acetyltransferase.

Inhibition of human eosinophil chemotaxis in vitro by the anti-allergic agent emedastine difumarate

Emedastine difumarate (emedastine), an anti-allergic agent with anti-histaminic properties, was studied for its effect on human eosinophil chemotaxis induced by platelet activating factor (PAF). Peripheral blood eosinophils (98% purity) were obtained from healthy donors and chemotaxis assay were performed in microchemotaxis chambers. Emedastine showed a significant inhibitory effect on 10(-6) M PAF-induced eosinophil chemotaxis, in dose dependent fashion, at concentrations from 10(-6) to 10(-8) M. Conversely, no inhibitory effect was observed on human neutrophil chemotaxis. Pretreatment of eosinophils with Pyrilamine did not affect PAF-induced eosinophil chemotaxis. Thus emedastine appears to possess a potent and selective inhibitory effect on eosinophils chemotaxis, an action which is probably unrelated to its anti-histamine properties.

Local production of interleukin-5 by T lymphocytes is associated with recruitment of eosinophils in patients with eosinophilic granuloma of the soft tissue

Eosinophilic granuloma of the soft tissue (EOSG) is a rare disease of unknown cause. Since the in vivo mechanism of eosinophilia remains unclear, the present study was performed to investigate the mechanism of the infiltration of eosinophils into the granuloma tissue. Immunohistochemical techniques and an eosinophil chemotactic assay were used in analysis. Peripheral blood eosinophils obtained from one patient showed an increased chemotactic response against tissue extract that was inhibited by pretreatment with anti-IL-5 antibodies. Eosinophils obtained from the peripheral blood of patients with EOSG showed a significant increase in chemotactic activity toward 10(-9) M recombinant human (rh) IL-5 versus that of healthy individuals, whereas eosinophils from granuloma tissue showed no chemotactic response toward rhIL-5, indicating that IL-5 may deactivate the eosinophils. Immunohistochemical studies showed that CD4+ cells were predominantly found in the extrafollicular region, along with interleukin-5+ (IL-5) cells. Staining of the adjacent 3-micrometers sections for CD3, eosinophils, and IL-5 revealed that most of the IL-5 immunoreactive CD3+ cells exhibited cytoplasmic staining. Conversely, 97% of IL-5+ eosinophils were stained peripherally in a ring-like manner, suggesting that IL-5 was bound to its cell surface receptor on the eosinophil. IL-5 mRNA expression was detectable in the CD3+T lymphocytes but not in eosinophils from granuloma tissue. These findings suggest that locally produced IL-5 from T lymphocytes may enhance the infiltration of eosinophils into the eosinophilic granuloma.

Kappa-casein suppresses melanogenesis in cultured pigment cells

The effects of bovine milk proteins on melanogenesis in B16 cells were examined. Both whey protein isolate and casein exhibited depigmenting properties. Among the major protein components of milk--including beta-lactoglobulin, alpha-lactalbumin, alpha-, beta-, and kappa-casein--only kappa-casein exhibited the depigmenting effect. However, the carboxyl terminal peptide of kappa-casein, glycomacropeptide, did not show this activity. Also, kappa-casein promoted the proliferation of the cells and inhibited the activity of tyrosinase in the cells. These results indicate that kappa-casein acts as a melanogenesis-suppressing modulator.

Identification of the functional region on the superantigen Yersinia pseudotuberculosis-derived mitogen responsible for induction of lymphocyte proliferation by using synthetic peptides

Yersinia pseudotuberculosis-derived mitogen (YPM) is the unique Gram-negative bacillary superantigen known. In order to identify the regions on the YPM molecule involved in its superantigenic activity, seven overlapping peptides of the entire YPM molecule were synthesized and tested to evaluate their effects on the YPM-induced proliferation of human peripheral blood lymphocytes. A peptide corresponding to the N-terminal amino acid sequence (1-23) was found to inhibit YPM-induced lymphocyte proliferation in a concentration-dependent manner. The N-terminal peptide was found to show no inhibition of the proliferation induced by the other superantigen (staphylococcal enterotoxin B) or the other T-cell mitogen pertussis toxin, indicating that the inhibition is specific to YPM-induced proliferation. Thus, we have identified the N-terminal region (1-23) of the YPM as one of the functional regions responsible for its superantigenic activity.

Muscarinic acetylcholine receptors on human lymphocytes in patients with Menière's disease

To investigate patients with Menière's disease and the association of cholinergic hyperreactivity, we performed muscarinic acetylcholine receptor assay using peripheral blood lymphocytes from patients with Menière's disease and non-dizzy, non-allergic control subjects. Cholinergic receptor maximal bindings (Bmax) and dissociation constants (Kd) were compared between the two groups, indicating the number and the affinities of the receptors, respectively. The receptor Bmax value in Meniére's patients during the remission state (108.6 +/- 51.2 fmol/l x 10(6) lymphocytes) was higher than that in normal controls (45.8 +/- 9.2 fmol/l x 10(6) lymphocytes) (p < 0.01). Furthermore, during an exacerbated state, Bmax was increased significantly (223.7 +/- 90.2 fmol/l x 10(6) lymphocytes) compared to the remission state (p < 0.01). In contrast, Kd values for the receptor did not differ between the two groups. These results suggest that patients with Menière's disease have cholinergic hyperreactivity, which may be further upregulated during a state of exacerbation due to an increase in the number of cholinergic receptors.

Leukemia inhibitory factor (LIF) enhances trophoblast differentiation mediated by human chorionic gonadotropin (hCG)

We investigated the effect of LIF on the differentiation of trophoblasts. Isolated cytotrophoblasts were cultured with and without LIF and cell smears were immunocytochemically analyzed, using anti-hCG antibody. The percentage of differentiated trophoblasts stimulated by 10ng/ml of LIF was about 2.5-fold that in the control culture. The effect of LIF in inducing the differentiation of cytotrophoblasts to syncytiotrophoblasts was dose-dependent. The same effect was shown when hCG was added to the medium. This enhancing effect of LIF on trophoblast differentiation was blocked by adding anti-hCG antibody to the culture system. These results indicate that LIF enhanced trophoblast differentiation by stimulating hCG production in trophoblasts, and not by exerting a direct effect on the trophoblasts.

Chemical modification and inactivation of phospholipases A2 by a manoalide analogue

Chemical modification and inactivation of bovine pancreatic, porcine pancreatic, Naja naja atra and Pseudechis australis phospholipases A2 (PLA2s), belonging to Group I, and of Trimeresurus flavoviridis, Vipera russelli russelli and Agkistrodon halys blomhoffii PLA2s, belonging to Group II, were investigated by the use of a manoalide (MLD)-analogue, 1-(2,5-dihydro-hydroxy-5-oxo-3-furanyl)-8,12-dimethyl-4-formyl-3,7, 11-tridecatrienol. At appropriate time intervals, residual PLA2 activities towards monodispersed, anionic mixed micellar and non-ionic mixed micellar substrates were measured. We tested the protective effect of micellar n-dodecylphosphocholine (n-C12PC) on enzyme inactivation. Inactivation of pancreatic PLA2s (Group I) was only observed towards anionic mixed micellar substrates. This inactivation was completely prevented by the presence of micellar n-C12PC. From a fragmentation study of modified bovine pancreatic PLA2 using lysyl endopeptidase, we speculated that Lys-56 of this enzyme was modified by MLD-analogue and that this modification was responsible for enzyme inactivation. Inactivation of non-pancreatic PLA2s was observed towards all types of substrate, except that no significant inactivation of N. naja atra PLA2 (Group I) towards monodispersed substrate was noted. Micellar n-C12PC protected N. naja atra PLA2 (Group I) completely from inactivation by MLD-analogue, but had lesser protective effects on P. australis PLA2 (Group I), T. flavoviridis and V. russelli russelli PLA2s (Group II). However, no significant protection of A. halys blomhoffii PLA2s (Group II) activity was observed. These results indicate that the inactivation of pancreatic and N. naja atra PLA2s originates from the modification of Lys residues at the interfacial recognition site, and that inactivation of P. australis, T. flavoviridis and V. russelli PLA2s arises from the modification of Lys residues at the catalytic site, interfacial recognition site and regions outside both sites. The inactivation of A. halys blomhoffii PLA2 was assumed to be due to the modification of Lys residues outside the two sites described above.

'Bystander killing' induces apoptosis and is inhibited by forskolin

'Bystander killing' is a term used to describe the broad cell death associated with the transduction of the herpes simplex virus thymidine kinase gene (HSV1-tk) and administration of nucleoside analogs and which extends the killing effect to adjacent cells not transduced with HSV1-tk ('bystander cells'). HSV1-tk negative cells can be killed by co-culture with HSV1-tk positive cells at a ratio as small as one HSV1-tk positive to 32 HSV1-tk negative cells (1:32). In this report, several aspects of bystander killing are characterized. First, the sensitivity to bystander killing is shown to differ among cell lines. Second, cell-to-cell contact, or at least proximity between cells, is demonstrated to be necessary for bystander killing. Third, forskolin is shown to inhibit bystander killing. We also show that bystander killing is not species specific. Finally, it is demonstrated that cell death induced by bystander killing is mediated via apoptosis.

Binding mode of phospholipase A2 with a new type of phospholipid analog having an oxazolidinone ring

Inhibition of phospholipases A2 (PLA2s) by a new type of monodispersed phospholipid analog, 3-dodecanoyl-4-phosphatidylcholinohydroxymethyl-2-oxazolidinone (oxazolidinone-PC), was investigated by the pH stat assay method using monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC) as the substrate. The PLA2s used were those from bovine pancreas and cobra (Naja naja atra) venom (Group I) and from Japanese mamushi (Agkistrodon halys blomhoffii) venom (Group II). This new-type substrate analog was shown to inhibit competitively both types of venom and bovine pancreatic enzymes by binding to the active site in a similar manner to the carboxamide-type analog 2-dodecanoyl-amino-1-hexanol-phosphocholine (amide-PC). The binding of a stereoisomer, (R)-amide-PC, to N. naja atra (Group I) and A. halys blomhoffii (Group II) PLA2s was facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of (R)-oxazolidinone-PC to the N. naja atra (Group I) enzyme was found to be independent of Ca2+ binding, while its binding to the A. halys blomhoffii (Group II) enzyme was markedly facilitated by the binding of Ca2+ to the enzyme. The binding of (R)-amide-PC to N. naja atra PLA2 (Group I) was markedly influenced by the ionization state of the catalytic residue His 48, whereas the binding of (R)-oxazolidinone-PC was found to be practically independent of the ionization state of this residue.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of Ca2+ in the binding of phospholipase A2 with a monomeric substrate and with its amide-type analog

Effects of Ca2+ on the kinetic parameters for the hydrolysis of monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC), catalyzed by Group I phospholipases A2 (PLA2s) from Pseudechis australis, Naja naja atra, and bovine pancreas and by Group II enzymes from Vipera russelli russelli, Agkistrodon halys blomhoffii, and Trimeresurus flavoviridis, were studied by the pH-stat assay method at 25 degrees C, pH 7.5-8.2, and an ionic strength of 0.1 or 0.2 in the absence or presence of an amide-type substrate analog, 2-dodecanoyl-amino-1-hexanol-phosphoglycol. The binding of genuine substrate to the Group II enzymes and that of its analog to the Groups I and II enzymes were markedly facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of genuine substrate to the Group I enzymes was found to be independent of the Ca2+ binding. The former result suggests that the structures of the Group II enzyme-genuine substrate complexes and both types of enzyme-analog complexes are generally stabilized by the Ca2+ binding, whereas the latter indicates that the structures of the Group I enzyme-genuine substrate complexes are already similar to those of their Ca2+ complexes and that, therefore, these enzyme-substrate interactions are independent of the Ca2+ binding.

Heterogeneous eosinophils of allergic rhinitis in chemotactic response

Chemotactic responses of eosinophils from patients with allergic rhinitis to 5 STO-2-derived eosinophil chemotactic factors (ECF), IL-3, IL-5 and GM-CSF were examined. The patients were divided into two groups: patients with perennial allergic rhinitis sensitive to Dermatophagoides farinae and those with seasonal allergic rhinitis sensitive to Japanese cedar pollen. There was no essential difference between chemotactic response of eosinophils from the former to STO-2-derived ECF and that from healthy individuals. However, eosinophils from patients with seasonal allergic rhinitis failed to respond to one of the STO-2-derived ECFs, ECF-P19. Before and after nasal antigen provocation, no change occurred in the chemotactic profiles. Furthermore, we found that eosinophils from both types of patients with allergic rhinitis responded not only to IL-3 and GM-CSF but also to IL-5 unlike those of healthy individuals.

Crystallization and preliminary X-ray study of Agkistrodon halys blomhoffii phospholipase A2 complexed with a specific inhibitor

Phospholipase A2 from the venom of Agkistrodon halys blomhoffii has been crystallized as a complex with a specific inhibitor, (S)-2-dodecanoyl-amino-3-hexanol-1-phosphoglycol. The complex crystals belong to the hexagonal space group, P6(1)22 (or P6(5)22), with cell dimensions of a = b = 61.13 A, and c = 173.15 A. The diffraction extends to at least 2.3 A resolution.

Nasal tissue eosinophils in allergic rhinitis

The density characteristics and functional heterogeneity of nasal tissue eosinophils were studied. The density distribution profiles of eosinophils from patients with allergic rhinitis (AR) showed peaks at densities of 1.068 to 1.084 g/ml, significantly lower than the densities of eosinophils in non-allergic patients with nasal polyps and chronic sinusitis (p < 0.01). The proportion of hypodense eosinophils in patients with AR was 43%; this was significantly greater than that in non-allergic subjects (p < 0.001). Patients with AR tended to have more EG2-positive tissue eosinophils. Furthermore, normodense eosinophils in nasal tissue tended to show a higher percentage of EG2-positive cells than hypodense eosinophils. On the other hand, circulating hypodense eosinophils showed a higher percentage of EG2-positive cells than normal density eosinophils. These results suggest that tissue eosinophils may be activated, and that the functional heterogeneity of eosinophils is dependent on factors other than cell density.

Pulse methylprednisolone therapy in the treatment of Wegener's granulomatosis

Five patients with Wegener's granulomatosis were treated with high-dose intravenous methylprednisolone (MTP) pulse therapy. Three out of five patients received MTP pulse therapy as the initial treatment and remission was achieved. Renal biopsy after the treatment confirmed the improvement of kidney involvement in 2 cases. Although the other two patients received MTP pulse therapy when a relapse occurred, the therapy could not suppress the progression of the disease. These observations suggest that MTP pulse therapy when given early may make it possible to suppress the progression of kidney involvement and improve the prognosis of the disease. Furthermore, it may also decrease the total doses of oral steroids and cyclophosphamide because of a strong anti-inflammatory and immunosuppressive action and consequently diminish the side effects. In conclusion MTP pulse therapy as the initial treatment may be beneficial in treating patients with Wegener's granulomatosis.

Structure of acidic phospholipase A2 for the venom of Agkistrodon halys blomhoffii at 2.8 A resolution

The crystal structure of acidic phospholipase A2 from the venom of Agkistrodon halys blomhoffii has been determined by molecular replacement methods based on the known structure of Crotalus atrox PLA2, a same group II enzyme. The overall structures, except the calcium-binding regions, are very similar to each other. A calcium ion is pentagonally ligated to two carboxylate oxygen atoms of Asp-49 and each carbonyl oxygen atoms of Tyr-28, Gly-30 and Ala-31. A reason why the former enzyme functions as monomeric form, while the latter one does as dimer, could be presumed by the structural comparison of these calcium-binding regions. Although Gly-32 is usually participated as a ligand in the coordination with calcium ion in group I PLA2, it is characteristically replaced to Ala-31 in the present structure, and thus the coordination geometry of calcium ion is rather different from the usually observed one.

Kinetics of the hydrolysis of micellar substrates catalyzed by snake venom phospholipases A2

Effects of Ca2+ on the kinetic parameters for the hydrolysis of mixed micelles of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (diC16PC) with Triton X-100, catalyzed by a cobra (Naja naja atra) (Group I) and a Habu (Trimeresurus flavoviridis) (Group II) PLA2s, were studied and compared with the results reported for other Group I and II enzymes. The substrate bindings to Group I enzymes were independent of the Ca2+ binding, whereas the substrate bindings to Group II enzymes were facilitated more than 10 times by the Ca2+ binding to the enzymes. The result for Group II enzymes, but not Group I enzymes, seemed compatible with the hypothesis for interpreting the catalytic mechanism that an intermediate complex should be stabilized by the coordination of the bound Ca2+ with the phosphoryl group and the carbonyl oxygen atom of the ester bond at the sn-2 position of the bound substrate molecule [Verheij et al. (1980) Biochemistry 19, 743-750 and (1981) Rev. Physiol. Biochem. Pharmacol. 91, 91-203]. The pH dependence of the kinetic parameters for the hydrolysis of the mixed micellar diC16PC, catalyzed by the cobra (N. naja atra) (Group I) and Habu (T. flavoviridis) (Group II) PLA2s, was also studied. The pK values of the catalytic group, His 48, and Tyr 52 for N. naja atra PLA2, shifted from 7.25 to 7.70 and from 10.30 to 10.85, respectively, and the corresponding values for T. flavoviridis PLA2 shifted from 5.80 to 6.95 and from 10.10 to 10.76, respectively, on binding of the micellar substrates to the enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopic observation of killer cells induced by mixed culture of lymphocytes with autologous cancer cells and further culture with recombinant interleukin-2

Peripheral blood lymphocytes obtained from 2 patients with hypopharyngeal cancer were cultured with mitomycin C treated autologous tumor cells (autologous MLTC) for 10 days and further cultured with recombinant interleukin 2 (rIL-2). In one case 10-day MLTC induced increase of CD25-positive lymphocyte count, indicating that IL-2 receptors were expressed dominantly by the autologous tumor stimulation, and further culture with rIL-2 differentiated killing activity against autologous tumor cells. In the other case, however, MLTC alone induced killing activity against autologous tumor cells, indicating that the tumor cells from this patient might possess stimulatory activity sufficient to induce mature killer cells. Electron microscopic observation of the morphological features of lymphocytes cultured for 10 days revealed mostly small lymphocytes with low incidence of cytoplasmic granules. Further culture with rIL-2, however, induced slightly larger lymphocytes with well-developed microvilli, and cytoplasmic granules were found in many of the cells. Lymphokine activated killer (LAK) cells induced by culture of lymphocytes with rIL-2 alone were much larger and had long microvilli and abundant cytoplasmic granules, and were apparently morphologically different from the killer cells initiated by MLTC. The small lymphocytes induced by autologous MLTC alone might be autologous tumor specific cytotoxic T lymphocytes (CTL) and/or CTL precursors. Further culture with rIL-2 induced maturation of the CTL. However, the nature of the cytoplasmic granules remains obscure.

Pharmacological actions of chemically-modified phospholipase A2 from the venom of Trimeresurus flavoviridis on the smooth muscle of the rat stomach fundus

The pharmacological activities of Trimeresurus flavoviridis phospholipase A2 (PLA2) and their chemically-modified PLA2 were characterized by measuring the contraction of rat stomach fundus strips. The native PLA2 produced a contraction of rat fundus strips. The alpha-amino-modified enzyme induced an almost identical contraction of the fundus with that of the native enzyme, whereas His-modified and Lys-modified enzymes induced a markedly decreased contraction as compared with the native enzyme. These results demonstrate that lysine and histidine residues but not the alpha-amino group in the PLA2 molecule are essential for contractile activity of the stomach fundus.