Nuclear localization and dominant-negative suppression by a mutant SKCa3 N-terminal channel fragment identified in a patient with schizophrenia

The small conductance calcium-activated K+ channel gene SKCa3/KCNN3 maps to 1q21, a region strongly linked to schizophrenia. Recently, a 4-base pair deletion in SKCa3 was reported in a patient with schizophrenia, which truncates the protein at the end of the N-terminal cytoplasmic region (SKCa3Delta). We generated a green fluorescent protein-SKCa3 N-terminal construct (SKCa3-1/285) that is identical to SKCa3Delta except for the last two residues. Using confocal microscopy we demonstrate that SKCa3-1/285 localizes rapidly and exclusively to the nucleus of mammalian cells like several other pathogenic polyglutamine-containing proteins. This nuclear targeting is mediated in part by two polybasic sequences present at the C-terminal end of SKCa3-1/285. In contrast, full-length SKCa3, SKCa2, and IKCa1 polypeptides are all excluded from the nucleus and express as functional channels. When overexpressed in human Jurkat T cells, SKCa3-1/285 can suppress endogenous SKCa2 currents but not voltage-gated K+ currents. This dominant-negative suppression is most likely mediated through the co-assembly of SKCa3-1/285 with native subunits and the formation of non-functional tetramers. The nuclear localization of SKCa3-1/285 may alter neuronal architecture, and its ability to dominantly suppress endogenous small conductance K(Ca) currents may affect patterns of neuronal firing. Together, these two effects may play a part in the pathogenesis of schizophrenia and other neuropsychiatric disorders.

Life-threatening pulmonary edema following unilateral stent implantation for bilateral branch pulmonary stenosis: recovery after contralateral stent implantation

A 13-year-old girl, who was suffering complications with bilateral pulmonary artery stenosis after intracardiac repair for tetralogy of Fallot, suffered life-threatening left pulmonary bleeding and edema following inadvertent unilateral stent implantation for a left pulmonary stenosis. Pulmonary edema and subsequent hypoxia persisted despite intensive medical treatment; however, contralateral stent deployment resolved her symptoms quickly.

Balloon aortic valvuloplasty in children: a multicenter study in Japan

A questionnaire was used to survey the experience of 8 Japanese institutions with percutaneous transluminal aortic valvuloplasty (PTAV) in children. Among 99 procedures reported in 88 patients, sufficient data for analysis was obtained from 76 procedures in 72 patients. In those 76 procedures the pressure gradient decreased significantly from 68+/-25 (20-140) to 33+/-22 (0-100) mmHg (p<0.01), whereas aortic regurgitation (AR) increased at least one grade in 26 cases (34%). None of the parameters analyzed in this study were predictors of an increase in AR. The reduction in pressure gradient was judged as good in 44 of the 76 procedures (58%). A larger ring diameter, larger balloon diameter and larger ratio balloon diameter/the normal predicted diameter of the aortic valve ring significantly contributed to an effective reduction of pressure gradient. Follow up data (mean interval, 4 years) was available for 26 of 39 clinically effective procedures. AR progressed at least 1 grade in 11 (42%), and the pressure gradient re-developed to more than 50mmHg in 2 cases (8%). In Japan, PTAV has been accepted as a useful procedure for valvular aortic stenosis in children, but progressive AR or re-development of the pressure gradient is not uncommon even after clinically effective PTAV.

Imbalance of cusp width and aortic regurgitation associated with aortic cusp prolapse in ventricular septal defect

The Doppler echocardiograms of the aortic valve and associated aortic regurgitation (AR) were reviewed in 72 patients with a ventricular septal defect (VSD). Group I comprised 13 patients without any deformity of the aortic cusp for > or = 10 years, group 2 included 35 patients who did not develop AR for > or = 10 years after right coronary cusp prolapse (RCCP) was first detected, group 3 comprised 11 patients with RCCP and AR in whom the AR remained subclinical for > or = 10 years, and group 4 was 13 patients who underwent surgical treatment because of moderate to severe AR. The cusp imbalance index [width of right (R) or non- (N) coronary cusp/width of left coronary cusp (L)] was compared among the 4 groups. R/L or N/L was larger in group 4 than in groups 1-3; R/L exceeded 1.30 in all the patients in group 4, whereas it was less than 1.30 in all the atients in groups 1-3. Two patients in group 4 with non-coronary cusp prolapse had an N/L greater than 1.50. No other patients in any group had an N/L larger than 1.20. An imbalance of cusp width may predict possible progressive deterioration of AR.

[Aspiration and drainage for a gas-producing brain abscess causing delayed bleeding from the abscess capsule--a case report]

A 65-year-old man was admitted with the complaint of gait disturbance. CT scan revealed a low density lesion in the right parietal lobe. MRI was carried out 3 days after admission, the lesion showing low intensity on T1 WI and T2 WI. Gd-DTPA enhanced T1 WI showing abnormal enhancement surround it. CT scan then revealed a gas bubble in the lesion 12 days after admission, so we diagnosed it as gas-producing brain abscess and aspiration, drainage and irrigation with antibiotics were performed. Although, the brain abscess was reduced in size after the operation, the lesion expanded again 2 weeks after the operation. MRI was performed and the lesion showed iso-intensity on T1 WI and high intensity on T2 WI. Emergent aspiration and drainage were performed and uncoagulated old-hematoma-like matter such as chronic subdural hematoma was removed. As significant neovascularization with inflammatory cells had been detected in the capsule of the brain abscess, we suspected that aspiration and drainage surgery for brain abscess may cause delayed bleeding from the capsule of the abscess. We conclude that attention should be drawn to such a complication.

[The early hemorrhage and development of a bacterial aneurysm after a cerebral ischemic attack caused by a septic embolism--a case report]

A 71-year-old female was admitted with the complaints of dysarthria and right hemiparesis. CT scan revealed subarachnoid hemorrhage in the left cerebral sulcus. The first angiography was performed 3 days after the onset and left carotid angiography revealed a small aneurysm arising from the left middle cerebral artery. After 3 weeks of antibiotic therapy, the second angiography showed the aneurysm to be clearly enlarged, so it was resected. The patient complained of marked dysarthria a day after the operation and CT scan revealed a new infarction in the right frontal lobe. The third angiography showed an aneurysm arising from the right middle cerebral artery and the fact that two peripheral arteries of the aneurysm had disappeared 3 weeks after the first operation. The second operation was performed and a bacterial aneurysm was resected. The patient left the hospital without any neurological deficits. Septic embolism is the most important complication of infective endocarditis and it is usually presented with subarachnoid hemorrhage and intracerebral hemorrhage caused by ruptured bacterial aneurysms. In this case the septic embolism occurred two times. At each time cerebral ischemic attacks were presented. The reason why this case presented with ischemic symptoms was suspected to be that embolisms occurred at the trifurcation of the distal middle cerebral arteries. We were able to detect a bacterial aneurysm angiographically 3 days after the ischemic attack and we suspected that a bacterial aneurysm had been able to develop within 3 days after the septic embolism.

Use of a 0.052" Gianturco coil to embolize a persistent right superior vena cava following extracardiac total cavopulmonary connection

A persistent right superior vena following extracardiac total cavopulmonary connection was occluded using a 0.052" Gianturco coil combined with a 3 Fr biopsy forceps. Controlled delivery of a 0.052" Gianturco coil is a safe and effective procedure to occlude a large anomalous vessel other than a large persistent arterial duct.

Helical computer assisted tomography in pulmonary hypertension complicating left-to-right shunts--correlation with pulmonary hemodynamics

The present study analyzed the helical computer-assisted tomography (CAT) findings in 30 patients with pulmonary hypertension (PH) associated with left-to-right shunts; specifically, ventricular septal defect, 23; atrioventricular septal defect, 6; patent ductus arteriosus, 1. Eight patients had 21 trisomy. Age ranged from 1 to 18 (mean, 4.1) months, and body weight ranged from 2.6 to 10.7 (mean, 4.9) kg. In all patients, the chest CAT revealed patchy areas of high and low attenuation (mosaic pattern) and regional atelectasis in the lung fields. The volume of low attenuated lesions and of atelectasis, and the total lung volume were derived from integration of areas measured on the CAT image. The ratios of low attenuated lesion/total lung volume (Lo), volume of atelectasis/ total lung volume (Ate) and low attenuated lesion and volume of atelectasis/total lung volume (Lo&Ate) were compared with hemodynamic parameters measured at cardiac catheterization. The pulmonary to systemic resistance ratio correlated with Lo (r=0.61, p<0.01) and Lo&Ate (r=0.69, p<0.01), whereas the pulmonary vascular resistance correlated with Ate (r=0.53, p<0.01). Lo, Ate and Lo&Ate in the chest CAT are reliable parameters that can be used to estimate pulmonary vascular resistance in patients with PH associated with left-to-right shunts.

Selective down-regulation of high-affinity IgE receptor (FcepsilonRI) alpha-chain messenger RNA among transcriptome in cord blood-derived versus adult peripheral blood-derived cultured human mast cells

Substantial numbers of human mast cells (MCs) were generated from umbilical cord blood (CB) and from adult peripheral blood (PB). A single CB progenitor produced 15 436 MCs, whereas a single PB progenitor produced 807 MCs on average. However, PB-derived MCs were far more active than CB-derived MCs in terms of high-affinity IgE receptor (FcepsilonRI)-mediated reactions. One million sensitized PB-derived MCs released 3.6 microg histamine, 215 pg IL-5, and 14 ng granulocyte macrophage-colony-stimulating factor (GM-CSF), whereas 10(6) sensitized CB-derived MCs released only 0.8 microg histamine, 31 pg IL-5, and 0.58 ng GM-CSF on anti-IgE challenge. However, ionophore A23 187 released similar levels of histamine from the 2 MC types. PB-derived MCs highly expressed surface FcepsilonRI alpha chain, and CB-derived MCs almost lacked it in the absence of IgE. PB-derived MCs expressed approximately 5 times higher levels of messenger RNA (mRNA) for FcepsilonRI alpha chain than CB-derived MCs, but mRNAs for beta and gamma chains of the receptors were equally expressed. Among the approximately 5600 kinds of full-length human genes examined by using the high-density oligonucleotide probe-array system, FcepsilonRIalpha was ranked the fifth most increased transcript in PB-derived MCs. The 4 other increased transcripts were unrelated to MC function. These results suggest that IgE-mediated reactions may be restricted during early infancy through the selective inhibition of FcepsilonRIalpha transcription, which is probably committed at progenitor stages and is, at least in part, cytokine-insensitive.

Coagulation profile, hepatic function, and hemodynamics following Fontan-type operations

We analyzed retrospectively the relationship between coagulation profile, and either hepatic function or hemodynamics, in patients who had undergone a Fontan-type procedure, comparing them, first, with a control group of 12 patients without significant hemodynamic abnormality, and, second, with a group of 14 patients who had not undergone a Fontan procedure, but whose mean right atrial pressure exceeded 8 mmHg. Follow-up catheterization had been performed in all 30 patients submitted to the Fontan-type operation. Prothrombin time, and factor XIII, were significantly lower in those who had undergone the Fontan procedure than in the other groups. Those submitted to the Fontan operation also had lower levels of protein C than controls, and their levels of plasminogen were lower than the patients with high right atrial pressure. Both aspartate aminotransferase and alanine aminotransferase were higher in those undergoing the Fontan procedure than in the other groups, while gamma-glutamyltranspeptidase in these patients was higher than in the control group. Mean right atrial pressure was highest in those undergoing the Fontan procedure, while cardiac index was lowest. Prothrombin time was correlated to some extent with aspartate aminotransferase, mean right atrial pressure, and cardiac index. Protein C correlated with both aspartate aminotransferase and mean right atrial pressure, while factor XIII correlated with alanine aminotransferase, mean right atrial pressure, and cardiac index. Aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltranspeptidase, parameters of hepatic function, correlated significantly with mean right atrial pressure. In those who had undergone the Fontan procedure, decreased synthesis of pro-and anti-coagulant factors is a risk factor for both thrombosis and bleeding. Abnormal hemodynamics, in the absence of a right sided pumping chamber, may predispose to subclinical hepatic dysfunction, leading to selective disturbances of protein synthesis.

Incidence of Spontaneous Closure of Outlet Ventricular Septal Defect

The present study examined the Doppler echocardiograms of 742 patients with an outlet ventricular septal defect (VSD) who were seen at the National Cardiovascular Center from 1987 to 1999. Of these, 450 patients were followed for longer than 1 year; 161 of these 450 were younger than 12 months when first examined. During follow-up, Doppler echocardiographic examination was repeated at least once a year. The medical charts of these patients were reviewed. Doppler echocardiographic findings were analysed in patients whose defect closed spontaneously:spontaneous closure at the age of 1-25 years was identified in 17 (3.8%) of 450 patients who were followed for longer than 1 year, and 7 (4.3%) of the 161 patients who were younger than 12 months at the first examination. All closed VSDs were originally smaller than 4mm. Although 5 cases of 17 developed trivial deformity of the right coronary cusp, suggesting a prolapse, this did not progress. Of these 5, trivial aortic regurgitation (AR) was detected in one patient, while another patient in the group of 17 developed trivial AR without any deformity of the right coronary cusp. Aortic regurgitation was not progressive in either patient. An outlet VSD closes spontaneously in a small percentage of patients without developing progressive AR.

[Analysis of patients with middle lobe and lingular syndrome complicated with nontuberculous mycobacterosis, chronic sinusitis, or bronchopulmonary tuberculosis]

The clinical characteristics and chest CT scan findings in 77 cases of middle lobe and lingular syndrome, many of which were complicated with nontuberculous mycobacteriosis (21 cases, 27.3%), chronic sinusitis (16, 20.8%), or bronchopulmonary tuberculosis (11, 14.3%) are reported. Sixteen (76.2%) cases complicated with nontuberculous mycobacteriosis and 14 (87.5%) cases complicated with chronic sinusitis had granular shadows with dilated bronchi of both middle lobe and lingular in their chest CT scans. Granular shadows with a thickening of the bronchial wall or dilated bronchi were common characteristics of the chest CT scans of the patients with nontuberculous mycobacteriosis. However, cicatrization atelectasis of either middle lobe or lingular was the most common finding in patients with bronchopulmonary tuberculosis.

Overcoming of radioresistance in human gliomas by p21WAF1/CIP1 antisense oligonucleotide

Malignant gliomas are highly resistant tumors against gamma-irradiation and contained overexpression of p21WAF1/CIP1 (p21). Overexpression of p21 enhanced clonogenic survival and suppressed apoptosis after gamma-irradiation in human brain tumor cell lines with or without p53 protein deficiency. The effect of antisense oligonucleotide to p21 against the gamma-irradiation-induced apoptosis and cytotoxicity in malignant glioma cell lines was examined. Antennapedia homeodomain internalization peptide was used as an insertion vector. The high transfection efficiency of Antennapedia homeodomain internalization peptide joined with antisense oligonucleotide was observed. The pretreatment with antisense oligonucleotide enhanced the gamma-irradiation-induced apoptosis and cytotoxicity in radioresistant glioma cells. p21 may represent an important new target for radiosensitization protocols, possibly involving antisense oligonucleotide directed against p21.

[Study on pulmonary cryptococcosis disclosed by chest radiographic screening in Nagasaki Prefecture]

We conducted a retrospective investigation of 20 cases of pulmonary cryptococcosis discovered by chest radiographic screening in Nagasaki Prefecture among 2,011,577 persons over a period of 9 years, Apr. 1989-Mar. 1998. Eight males and 12 females between 15 and 72 years of age(mean: 46.6 years) were diagnosed as having pulmonary cryptococcosis. The mean detectability of pulmonary cryptococcosis by screening was 0.99 per 10(5) persons: 1.30 for residents, 0.51 for school children and 0.80 for workers. Chest radiography showed shadows of solitary nodules in 9 patients, multiple nodules in 4, infiltration in 4 and others in 3. Cavities were noted in 7. However, it was difficult to distinguish between pulmonary cryptococcosis from pulmonary tuberculosis and pulmonary cancer based on radiographic data alone. Final diagnoses for 11 and 3 patients, respectively, were made using TBLB or BAL, and lung biopsy. Sixteen patients each underwent an Eiken-Latex agglutination test (serum cryptococcus antigen test) and 15 (93.8%) had positive results. The serum antigen level thus appears to be a useful indicator in the supplementary serological diagnosis of pulmonary cryptococcosis.

[A case of metastatic tumor of the pituitary gland presenting as a subarachnoid hemorrhage]

We reported the case of a 55-year-old man with metastatic tumor of the pituitary gland who suffered from symptomatic pituitary apoplexy with subarachnoid hemorrhage. The patient, who had sigmoid colon carcinoma and left parietal metastatic brain tumor, developed severe headache and decrease of right visual acuity. CT showed a pituitary mass with subarachnoid hemorrhage. Transsphenoidal surgery was performed after replacement therapy with corticosteroids. Histological examination revealed metastasis of adenocarcinoma. Pituitary apoplexy is an unusual manifestation of metastatic pituitary tumor. The case of metastatic tumor of the pituitary gland presenting as subarachnoid hemorrhage such as this case is especial rare.

[A case report of TS-1 in a patient with advanced gastric cancer]

TS-1 is an oral anticancer drug that produces biochemical modulation. TS-1 is composed of FT (tegafur), CDHP (gimestat, which inhibits 5-FU degradation enzyme), and Oxo (otastat potassium, which reduces 5-FU gastrointestinal toxicities), in a molar ratio of 1:0.4:1. We administered TS-1 to a 68-year-old female gastric cancer patient, after distal gastrectomy (Stage IV, cur C). As a result of abdominal CT, the diameter of metastatic lymph node increased before and after surgery, and before TS-1 (45 x 35 mm), but it was reduced after 1 course of TS-1 (37 x 25 mm), 2 courses of TS-1 (35 x 20 mm), 3 courses of TS-1 (30 x 20 mm), 4 courses of TS-1 (30 x 20 mm), and 6 months after 4 courses of TS-1 (20 x 20 mm). The reduction rate is 74.6%. The value of CA125 was reduced 74.4 to 8.6 after TS-1. Anorexia and back pain, which occurred after operation, disappeared after TS-1. There was no side effect over grade 3.

Lack of association with interleukin 1 receptor antagonist and interleukin-1beta gene polymorphisms in sarcoidosis patients

Interleukin-1beta (IL-1beta) and its endogenous antagonist, the interleukin-1 receptor antagonist (IL-1ra), play important roles in immune responses. In sarcoidosis, IL-1beta is reported to be increased whereas IL-1ra is decreased. It has recently been shown that polymorphisms in the IL-1ra and IL-1beta genes may account for variation in the two proteins. These polymorphisms are also reported to be associated with several autoimmune diseases. Since this might be expected to affect sarcoidosis, an investigation of 108 sarcoidosis patients and 113 healthy control subjects was performed. The IL-1ra genotype was determined using the polymerase chain reaction (PCR), and the IL-1beta genotype by PCR restriction fragment length polymorphism. We found no significant differences in IL-ra and IL-1beta genotypes between sarcoidosis patients and healthy controls. Furthermore, there was no association between the IL-1beta genotype and the roentgenographic stage, disappearance of chest X-ray shadows or organ involvement. In conclusion, there is no bias in the IL-1ra and IL-1beta genotype in Japanese sarcoidosis patients.

Gene expression of the phosducin-like protein in the retina

Phosducin, which is expressed abundantly in the retina, mediates phototransduction or signal transduction cascades by interacting with transducin or G-protein beta gamma-subunits. We have reported on the possibility that phosducin is expressed from a multiple gene family and that each phosducin may mediate G-protein-coupled signal transduction cascades. To elucidate new genes that may mediate signal transduction cascades in the retina and that may form a gene family with phosducin, we screened a bovine retinal cDNA library. During the screening, we identified a cDNA that looked the same as the phosducin-like protein of the rat, as reported by other investigators. We examined the gene expression in rat retina using semiquantitative polymerase chain reaction and compared it to that of other organs. One form generated by alternative splicing expressed in the retina was the same as in other tissues, but, interestingly, another form had differing tissue distribution and was expressed abundantly in the retina.

A case of multicentric Castleman's disease associated with renal amyloidosis and pure red cell aplasia

This is the first reported case of multicentric Castleman's disease (MCD) associated with renal amyloidosis and pure red cell aplasia (PRCA). Inguinal lymph node biopsy showed follicular hyperplasia with prominent germinal centers and plasma cell proliferation in the interfollicular areas. Renal biopsy specimens revealed intraglomerular amyloid deposits, defined as AA amyloidosis. Since amyloid deposits were not present in the gastric and rectal mucosal tissues, his renal disorder was found to be an unusual secondary amyloidosis associated with MCD. Following treatment by plasma exchange, there was progressive deterioration of anemia due to PRCA detected by bone marrow aspiration. Subsequently he was successfully treated with steroid pulse therapy not only for anemia but also for renal function.

Vitamin D receptor gene polymorphism and calcium metabolism in sarcoidosis patients

BACKGROUND

Hypercalcemia has been recognized as an important complication of sarcoidosis, caused by overproduction of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) at sites of granulomatous reactions. Polymorphism of the vitamin D receptor (VDR) gene has recently been shown to be related to bone mineral density, and also associated with hyperparathyroidism and risk of granulomatous disease. In light of the possible impact on hypercalcemia of sarcoidosis, an investigation of calcium metabolism and polymorphism of the VDR gene in sarcoidosis patients was carried out.

METHODS

Genotypes were determined using the polymerase chain reaction and restriction fragment length polymorphism. Maximum calcium, 1,25(OH)2D3, and intact PTH levels were also determined.

RESULTS

Depressed PTH levels were found in sarcoidosis patients, especially in those with the bb genotype, but there was no difference in 1,25(OH)2D3 levels among the VDR genotypes, and this polymorphism also had no association with onset of hypercalcemia.

CONCLUSION

From these results, we speculate that although the VDR gene polymorphism may affect the serum PTH level, it is not a risk factor for hypercalcemia in sarcoidosis.

An aortic valve with four leaflets

An aortic valve with four leaflets is a rare congenital malformation. It is usually diagnosed unexpectedly at autopsy, during replacement of the aortic valve, or by aortic angiography. Transthoracic cross-sectional echocardiography, however, can also delineate the structure of the aortic valve, and demonstrate the presence of valves with four leaflets

Evolution of aortic regurgitation following simple patch closure of doubly committed subarterial ventricular septal defect

We reviewed the Doppler echocardiographic findings of the aortic valve and associated aortic regurgitation (AR) in 55 patients who underwent patch closure of doubly committed subarterial ventricular septal defect (VSD). The maximal diameter of the VSD measured > or = 5 mm, whereas the postoperative follow-up interval was > or = 5 years. Twenty-three patients underwent closure before they developed aortic cusp prolapse or AR (group A). In 15 patients the VSD was closed when aortic cusp prolapse was recognized, but AR was absent (group B). Aortic cusp prolapse with AR was detected before closure in a further 15 patients (group C). Of 8 patients with no AR before closure, AR was detected during follow-up in 6 group A and in 2 group B patients. In group C, AR resolved after surgery in 4 patients, whereas AR grade improved in a further 8 patients and remained unchanged in 3. Although residual AR was more frequent in patients with aortic cusp prolapse and AR before closure, it was silent and asymptomatic.

Domain-specific mutations in TGFB1 result in Camurati-Engelmann disease

Camurati-Engelmann disease (CED, MIM 131300) is an autosomal dominant, progressive diaphyseal dysplasia characterized by hyperosteosis and sclerosis of the diaphyses of long bones. We recently assigned the CED locus to an interval between D19S422 and D19S606 at chromosome 19q13.1-q13.3, which two other groups confirmed. As the human transforming growth factor-1 gene (TGFB1) is located within this interval, we considered it a candidate gene for CED.

[The presence of air in epidural hematoma due to congenital bone defect in the mastoid tegmen--a case report]

Presence of air in acute epidural hematomas has been described by several authors. Although the air trapped in the epidural space is thought to be derived from the air-containing structure, there are some cases in which there is an absence of any demonstrable fracture involving air-containing structure. We report a very rare case of air in an epidural hematoma which was not related to fracture involving air-containing structure. The patient was a 30-year-old man whose left temporal bone was struck during a fall. CT scan revealed acute epidural hematoma with a large amount of air in the epidural space. We found many congenital bone defects in the mastoid tegmen during the operation and suspected that the air had been derived from them. The difference between our case and other cases reported was the amount of the air in epidural space. We suspected that air bubbles were derived from the fracture involving air-containing structure, while a large amount of air could be derived from congenital bone defects in the mastoid tegmen.

Regulation of chymase production in human mast cell progenitors

BACKGROUND

Although mature tryptase-positive mast cells (MCs) and tryptase and chymase double-positive MCs are recognized using in situ staining and are preferentially distributed in different tissues, recent findings suggest that tryptase-positive MCs can give rise to tryptase and chymase double-positive MCs.

OBJECTIVE

We investigated the regulation of chymase production in developing MCs.

METHODS

Human cord blood or peripheral blood cells were cultured in the presence of stem cell factor and IL-6 with or without IL-4 in methylcellulose or liquid medium. Intracellular chymase and tryptase were determined with immunocytochemistry, flow cytometry, and ELISA. Chymase messenger RNA expression was examined with 3 different methods, such as Northern blotting.

RESULTS

Flow cytometric analysis always showed a unimodal histogram of chymase-positive, as well as tryptase-positive, cells in the presence of various cytokines, even when chymase was not detected in some MCs with immunocytochemistry. The chymase protein expression increased by culture duration and was enhanced by cytokines, such as a high concentration of stem cell factor or IL-4. Chymase messenger RNA was expressed higher in immature MCs than mature chymase protein-rich MCs. We generated macroscopic MC colonies in methylcellulose by culturing CD34(+) cells for 10 weeks and measured cellular chymase, tryptase, and histamine. The chymase/histamine ratio widely varied (0.07-1.01) depending on MC colony, even under the same culture conditions, including IL-4, whereas the tryptase/histamine ratio was relatively constant (1.02-1.89).

CONCLUSION

All human MCs in culture are capable of producing chymase, and the production is clonally regulated at their progenitors by cytokine-independent mechanisms, as well as being totally controlled by cytokine-dependent mechanisms accompanied by maturation.