Identification of N(omega)-carboxymethylarginine as a novel acid-labileadvanced glycation end product in collagen

Collagen undergoes continuous non-enzymatic glycation during its long life period. The products resulting from the glycation reaction, so-called advanced glycation end products (AGEs), were regarded as potential pathogens of various diseases such as diabetic complications. Although several AGEs were identified from acid hydrolysates of glycated collagen, the major AGE(s) responsible for the diseases have not yet been fully characterized. Moreover, acid-labile constituents were decomposed during acid hydrolysis. To investigate these AGEs, we used the enzymatic hydrolysis method [Bensusan, Dixit and McKnight (1971) Biochim. Biophys. Acta 251, 100-108]. As a result, an acid-labile unknown compound was discovered from the digested glycated collagen. We identified this compound as N(omega)-carboxymethylarginine (CMA) by matrix-assisted laster-desorption ionization-MS and NMR. CMA gradually increased in collagen during incubation with glucose and the yield reached about 8 mol/mol of collagen, which is 100 times higher than that of pentosidine. This result suggests that CMA is a major AGE in collagen.

Red wine polyphenols inhibit proliferation of vascular smooth muscle cells and downregulate expression of cyclin A gene

BACKGROUND

Red wine polyphenols have been shown to contribute to the "French paradox" phenomenon, which consists of lower morbidity and mortality from coronary heart disease in the French population. Although vascular smooth muscle cell (VSMC) proliferation plays an important role in the progression of atherosclerotic lesions, the effects of red wine polyphenols on VSMC proliferation have not been elucidated.

METHODS AND RESULTS

We extracted the total polyphenolic fraction from red wine (RW-PF) by column chromatography. Treatment with RW-PF showed a potent inhibitory effect on the proliferation and DNA synthesis of cultured rat aortic smooth muscle cells (RASMCs). In contrast, the inhibitory effect of RW-PF on the proliferation of bovine carotid endothelial cells was observed only at much higher concentrations. To elucidate the molecular mechanisms of this antiproliferative effect of RW-PF on RASMCs, we investigated the effects of RW-PF on cell cycle regulation. RW-PF downregulated the expression of cyclin A mRNA and cyclin A promoter activity. In addition, RW-PF decreased the binding of nuclear proteins to the activating transcription factor (ATF) site in the cyclin A promoter and downregulated the mRNA levels of transcription factors, cAMP-responsive element-binding protein (CREB), and ATF-1.

CONCLUSIONS

These results suggest that the downregulation of cyclin A gene expression may contribute to the antiproliferative effect of red wine polyphenols on RASMCs through the inhibition of transcription factor expression.

Structure-activity relationship studies of chloromethyl ketone derivatives for selective human chymase inhibitors

Based on the SAR study of a classical chloromethyl ketone derivative, Z-PheCH2Cl 1, a series of compounds were synthesized. Among all the derivatives, compound 21 was found to be a potent human chymase inhibitor with no inhibitory activity against human leukocyte cathepsin G.

Changes in gastric acid secretion assayed by endoscopic gastrin test before and after Helicobacter pylori eradication

BACKGROUND

It remains controversial whether or not Helicobacter pylori infection causes altered gastric acid secretion. A novel test for evaluating gastric acid secretion (endoscopic gastrin test; EGT) has recently been developed.

AIM

To investigate by EGT the effects of H pylori eradication on the state of gastric acid secretion in patients with peptic ulcer.

METHODS

Twenty six patients with duodenal ulcer and 33 with gastric ulcer, for all of whom H pylori infection had been documented, were studied by EGT, histological examination of gastric mucosa, and measurement of plasma gastrin levels before and one and seven months after H pylori eradication.

RESULTS

In patients with duodenal ulcer, the mean EGT value before H pylori eradication was higher than that in H pylori negative controls, but it had decreased significantly seven months after the treatment. In contrast, the mean EGT value of patients with gastric ulcer before H pylori eradication was lower than that in H pylori negative controls, but it had increased one month after the treatment; this was followed by a slight decrease at seven months. In both groups, mean EGT values seven months after the treatment were not significantly different from the mean control value.

CONCLUSIONS

The reduced acid secretion in gastric ulcer patients and gastric acid hypersecretion in duodenal ulcer patients were both normalised after the clearance of H pylori.

Gender effects on age-related changes in brain structure

BACKGROUND AND PURPOSE

Previous reports have suggested that brain atrophy is associated with aging and that there are gender differences in brain atrophy with aging. These reports, however, neither exclude silent brain lesions in "healthy subjects" nor divide the brain into subregions. The aim of this study is to clarify the effect of gender on age-related changes in brain subregions by MR imaging.

METHODS

A computer-assisted system was used to calculate the brain matter area index (BMAI) of various regions of the brain from MR imaging of 331 subjects without brain lesions.

RESULTS

There was significantly more brain atrophy with aging in the posterior parts of the right frontal lobe in male subjects than there was in female subjects. Age-related atrophy in the middle part of the right temporal lobe, the left basal ganglia, the parietal lobe, and the cerebellum also was found in male subjects, but not in female subjects. In the temporal lobe, thalamus, parieto-occipital lobe, and cerebellum, brain volume in the left hemisphere is significantly smaller than in the right hemisphere; sex and age did not affect the hemisphere differences of brain volume in these regions.

CONCLUSION

The effect of gender on brain atrophy with aging varied in different subregions of the brain. There was more brain atrophy with aging in male subjects than in female subjects.

Helicobacter pylori infection inhibits reflux esophagitis by inducing atrophic gastritis

OBJECTIVE

Although it is widely accepted that Helicobacter pylori (H. pylori) infection is an important cause of atrophic gastritis, few studies have examined the relationship between H. pylori-induced atrophic gastritis and the occurrence of reflux esophagitis. The present study was aimed to examine the relationship between H. pylori infection, atrophic gastritis, and reflux esophagitis in Japan.

METHODS

A total of 175 patients with reflux esophagitis were compared with sex- and age-matched 175 control subjects. Diagnosis of H. pylori infection was made by gastric mucosal biopsy, rapid urease test, and serum IgG antibodies. Severity of atrophic gastritis was assessed by histology and serum pepsinogen I/II ratio.

RESULTS

H. pylori infection was found in 59 (33.7%) patients with reflux esophagitis, whereas it was found in 126 (72.0%) control subjects. The grade of atrophic gastritis was significantly lower in the former than in the latter. Among the H. pylori-positive patients, atrophic gastritis was milder in the patients with reflux esophagitis than in the patients without it.

CONCLUSIONS

These findings suggest that most cases of reflux esophagitis in Japan occur in the absence of H. pylori infection and atrophic gastritis, and it may also tend to occur in patients with milder gastritis even in the presence of H. pylori infection. Therefore, H. pylori infection may be an inhibitory factor of reflux esophagitis through inducing atrophic gastritis and concomitant hypoacidity.

[The production and coexistence of neurotransmitters in the neurons of the rat's locus coeruleus]

The production and coexistence of neurotransmitters in the locus coeruleus is reviewed. Immunocytochemical and in situ hybridization evidence demonstrated that the LC consists mainly of a single cell population that is producing GABA and 5-HT in addition to noradrenaline (NA) simultaneously in single neurons. The coexistence of GABA, 5-HT and NA in single LC neurons was proved by identifying the same neurons in adjacent sections alternately immunostained by different antisera. In situ hybridization detected the signals of glutamic acid decarboxylase mRNA and tryptophan hydroxylase mRNA indicating the presence of GABA/GAD system and the ability to produce 5-HT in many LC neurons. Neuroanatomical studies strongly suggest that a single NA cell population produces multiple transmitters so that the LC can play a role in mechanism controlling the human's adaptation to environmental changes. The present author introduces three different recent works concerning the LC. Caffé concluded that the concept of a NA-ergic cell population in all mammals is questionable. In similar cases to the domestic pig's LC, acetylcholinesterase activity, muscarinic and nicotinic receptor proteins should be checked. Tohyama et al. examined various receptor proteins in the LC and found localization of GAGAA, glutamate and glycine receptors. Maeda et al. reported that doaminergic neurons in the hypothalamus play a powerful role in mechanisms controlling the activity of NA-ergic neurons in the LC. Senile dementia of Alzheimer type causes marked atrophy and cell loss in the LC as well as the frontal lobe of the cerebrum. Molecular biology of the cell has been devoted to clarify the pathology of this fatal disease.

Effects of acupuncture on peripheral T lymphocyte subpopulation and amounts of cerebral catecholamines in mice

The aim of this study was to investigate the effects of acupuncture on peripheral lymphocyte subpopulations and cerebral catecholamines. In order to examine the effects of acupuncture, two experiments were performed. Experiment 1: Eighteen female mice (strain; C57BL/6) at the age of 7 weeks were divided three groups, (a) sham operated (control; n=6), (b) ovariectomized (OVX; n=6), and (c) ovariectomized and stimulated by subcutaneous needles on acupuncture point, Shenshu (BL23) at the both sides of the back for 20 days (OVX+Acu; n=6). These animals were sacrificed at 20 days after needle insertion, and the splenic lymphoid cells were examined by two-color flow cytometry, using monoclonal antibodies (mAb) to the cell surface antigens, CD3, CD4, CD8a and NK1.1 (CD56). In the ovariectomized (OVX) group, the peripheral CD4/CD8 ratio was significantly increased and the ratio of natural killer (NK) cells (CD3-NK1.1+; CD3 negative, NK1.1 positive) to T lymphocytes was decreased compared to the sham control group. In the ovariectomized with needle insertion (OVX+Acu) group, the CD4/CD8 ratio was reduced, but the NK cells ratio was not changed compared to the OVX group. Experiment 2: To investigate the acute effects of subcutaneous needle insertion, male C57BL/6 mice (7 weeks old) were used (n=6, each group). The acupuncture points Shen-shu (BL23) on the backs of the male mice were also stimulated by subcutaneous needles for 3 and 7 days. As a result, the CD4/CD8 ratio was significantly decreased at day 3 and day 7, compared to the control group. On the other hand the NK cells ratio and activated T-cells were increased at day 7. The mitogenic activities in the splenic lymphocytes were also increased by acupuncture stimulation at day 3. Catecholamine contents in the hippocampus were measured by high performance liquid chromatography with the electro-chemical detector (ECD-HPLC) method. No significant change was observed in either dopamine contents or norepinephrine; however, dopamine metabolite, homovanillic acid (HVA) and DOPAC (3,4-dihydroxyphenylacetic acid) were increased at day 3. The study suggests that acupuncture has effects on peripheral lymphocyte subpopulations and may modulate mitogenic activity. In addition, acupuncture may stimulate dopamine turnover.

Detection of mutations in the COL4A5 gene in over 90% of male patients with X-linked Alport's syndrome by RT-PCR and direct sequencing

X-linked Alport's syndrome is caused by mutations in the COL4A5 gene encoding the type IV collagen alpha5 chain (alpha5[IV]). Polymerase chain reaction-single-str and conformation polymorphism (PCR-SSCP) on genomic DNA has previously been used to screen for mutations in the COL4A5 gene, but this method was relatively insensitive, with mutations detected in less than 50% of patients. Here, we report a systematic analysis of the entire coding region of the COL4A5 gene, using nested reverse-transcription-polymerase chain reaction (RT-PCR) and the direct sequence method using leukocytes. This study examines twenty-two unrelated Japanese patients with X-linked Alport's syndrome showing abnormal expression of alpha5(IV) in the glomerular or epidermal basement membranes. Mutations that were predicted to be pathogenic were identified in 12 of the 13 male patients (92%) and five of the nine female patients (56%). Six patients had missense mutations, four had out-of-frame deletion mutations, three had nonsense mutations, and three had mutations causing exon loss of the transcript. The current study shows that nested RT-PCR and the direct sequence method using leukocytes are highly sensitive and offer a useful approach for systematic gene analysis in patients with X-linked Alport's syndrome.

Correlation between flow-mediated vasodilatation of the brachial artery and intima-media thickness in the carotid artery in men

Endothelial dysfunction has been reported to be the initial step in atherosclerosis. A noninvasive technique that uses ultrasound to measure the intima-media thickness of the carotid artery has been applied to evaluate localized atherosclerosis. This study was undertaken to elucidate whether endothelial dysfunction in the brachial artery is related to the intima-media thickness of the carotid artery. Thirty-four men with atherosclerosis (mean+/-SE age 61+/-2 years) and 33 age-matched men without clinical atherosclerosis were examined. The intima-media thickness and plaque formation of the common carotid artery were assessed by B-mode ultrasonography. We also noninvasively measured brachial artery diameter by the same ultrasound machine when the subjects were at rest, during reactive hyperemia, which causes endothelium-dependent vasodilatation, and after sublingual administration of nitroglycerin, which causes endothelium-independent vasodilatation. The atherosclerosis group had a significantly greater intima-media thickness of the common carotid artery than did the control group (1. 02+/-0.04 versus 0.91+/-0.03 mm, P<0.05). The flow-mediated diameter (FMD) increase (percent FMD=DeltaD/D x 100) in the atherosclerosis group was significantly smaller than that in the control group (2. 8+/-0.4% versus 5.1+/-0.6%, P<0.01). A significant negative correlation between the intima-media thickness of the carotid artery and percent FMD was found in all of the subjects. On multiple regression analysis, percent FMD showed a significant negative correlation with the intima-media thickness of the common carotid artery. These findings support the concept that endothelial dysfunction is significantly related to atherogenesis.

[Changes of activities of daily living and quality of life in a special nursing home during a one-year period]

The aim of this study was to examine the changes of activities of daily living and with quality of life of patients in a special nursing home founded in 1997 in Tsuwano Town, Shimane. We studied 19 special nursing home patients (age 69 to 96 years, mean age 83.3 years) for one year. To evaluate activities of daily living, mental decline, and quality of life, the Tokyo Metropolitan Institute of Gerontology Competence Index. Hasegawa's dementia rating scale, self-rating depression scale (Zung), apathy scale (Starkstein et al) and PGC morale scale (Lawton, subjective well-being scale) were used. The total score of the index of activities of daily living, self-rating depression scale, and the apathy score did not significantly change during one year. Although the total score of Hasegawa's dementia rating scale decreased significantly, PGC morale scale significantly improved during one year. These findings demonstrate that daily active rehabilitation had a beneficial effect on PGC morale scale in a special nursing home.

Acupuncture inhibits the decrease in brain catecholamine contents and the impairment of passive avoidance task in ovariectomized mice

The effects of acupuncture on the disorders elicited by abnormalities of endocrine system were investigated in ovariectomized mice. Female mice (strain; C57BL/6) were ovariectomized (OVX) and acupuncture points, Shenshu ([Japanese pictograph see text] : BL23) on both side of the back were continuously stimulated by subcutaneous needles for 20 days. After completion of experimental sessions, animals were sacrificed and specific brain regions were assayed for catecholamine contents by high performance liquid chromatography with electro chemical detector (ECD-HPLC). The mitogenic activities of splenic lymphocytes were measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTS) assay and alkaline phosphatase (ALP) assay. Furthermore, the effects of needle stimulation on learning and memory ability were studied by the step-through type passive avoidance test. Norepinephrine and dopamine contents in the frontoparietal cerebral cortex, ventral hippocampus and olfactory bulb were decreased in the OVX group, and both MTS activity and ALP activity were decreased 20 days after ovariectomy. The mean latent period was also shortened in the passive avoidance test in the OVX group. However, applying needle stimulation increased norepinephrine and dopamine contents in the brain regions, and enhanced mitogenic activities of splenic lymphocytes. The stimulation also improved memory-related behavior. It was concluded from this study that after mice were stimulated by subcutaneous needle insertion, overall changes were observed in central nervous system (including retention of memory) and immune functions. The study suggests that acupuncture improves the memory loss and decrease of immune responses accompanying aging and/or menopause, and the that it may have an important role in medical care for the elderly.

Relationship among activities of daily living, apathy, and subjective well-being in elderly people living alone in a rural town

BACKGROUND

There are limited psychological data on the quality of life and activities of daily living among elderly Japanese who live alone.

OBJECTIVE

The aim of this study was to examine the frequency of apathy and its correlation with activities of daily living and with subjective well-being in elderly people living alone in a depopulated rural area.

METHODS

We evaluated 96 individuals aged 70 years or older (mean age 77.8 years) who lived alone at home in a rural town. To evaluate activities of daily living, apathy, and subjective well-being, the Tokyo Metropolitan Institute of Gerontology Competence Index, the Apathy Scale, and the Philadelphia Geriatric Center Morale Scale (subjective well-being scale) were used.

RESULTS

Of the 96 subjects, 94 (97.9%) showed apathy. The total score of the index of activities of daily living was primarily related to age and the apathy score and less to the PGC Morale Scale score.

CONCLUSION

These findings demonstrate that apathy in subjects who live alone appears to exert a marked effect on their ability to perform routine activities of daily living.

Juzen-taiho-to, a Japanese herbal medicine, modulates type 1 and type 2 T cell responses in old BALB/c mice

Aging is associated with skewed type 2 (T2) T cell responses that may be modulated by herbal medicines. A group of Japanese herbal medicines, so-called "Hozai," have been used to improve the physical condition of the elderly. One representative "Hozai," Juzen-Taiho-To (JTX) appears to have beneficial effects on cancer patients. In this study we hypothesized that JTX modulated skewed T2 responses in the elderly. T1 and T2 responses against ovalbumin (OVA) were examined in old BALB/c mice fed JTX (0.2% w/w). We measured anti-OVA IgG1, IgG2a, and IgG2b antibody (Ab) levels after the primary and secondary OVA challenges; T1 and T2 responses augment IgG2a/IgG2b Ab and IgG1/IgE Ab production, respectively. We also assessed production of T1 and T2 cytokines (IFN-gamma and IL-5, respectively), and co-stimulatory molecule expression by regional draining lymph node cells. JTX-fed mice had higher IgG2b Ab and IFN-gamma production than controls along with lower IgG1 Ab. JTX did not alter IL-5 production or co-stimulatory molecule expression. Hoelen, an herbal component, induced similar changes. Our results indicate that JTX and Hoelen modulate T cell responses against OVA toward more balanced T1/T2 responses in old BALB/c mice. Such effects of JTX may help prevent the development of diseases associated with immunodisregulation in the elderly.

Infrared gold alloy brazing on titanium and Ti-6Al-4V alloy surfaces and its application to removable prosthodontics

PURPOSE

This study investigated the area size of the flow of a gold braze alloy on commercially pure titanium and Ti-6Al-4V alloy plates, and elemental composition at the interface was determined. In the second part of this study, the tensile strengths of titanium plates brazed using a gold alloy were investigated.

MATERIALS AND METHODS

Chips of Type IV gold alloy and silver braze alloys were melted onto commercially pure titanium and Ti-6Al-4V surfaces in a dental infrared radiation unit. Flow area of each braze alloy was measured using a digital image analyzer. Tensile specimens (n = 5) were also prepared by infrared brazing using the braze alloys. Five specimens for each combination of the two titanium plates and the two braze alloys were subjected to tensile loading using a Universal testing machine. Electronprobe microanalysis of x-rays at cross-section of the brazed joints to determine elemental composition across the interface, as well as scanning electron microscopic observation at the fracture surfaces, were also conducted.

RESULTS

The braze alloys flowed well and spread over the Ti and Ti-6Al-4V plates. Braze alloy type significantly influenced flow, and the gold alloy flowed less on the titanium materials. The mean tensile strengths of Ti and Ti-6Al-4V plates brazed using the gold braze alloy were 219 MPa and 417 MPa, respectively. The fracture surfaces of Ti-6Al-4V specimens with the gold braze alloy exhibited typical ductile behavior. Ti with the same braze alloy showed brittle surfaces. A greater concentration of Cu was found at the Ti with gold braze interface.

CONCLUSION

The flow and the tensile strength of the gold alloy coating on titanium surface by means of an infrared brazing is adequate for dental use.

Characterization of liposomes carrying von Willebrand factor-binding domain of platelet glycoprotein Ibalpha: a potential substitute for platelet transfusion

Platelet glycoprotein (GP) Ib/IX/V complex is a receptor for von Willebrand factor (vWf), which plays a crucial role in primary hemostasis by mediating platelet adhesion to injured blood vessels. We have expressed in CHO cells a fragment of GPIba that retained a vWf-binding function. The recombinant fragment (rGPIba) was incorporated into liposomes and evaluated their functions in vitro. rGPIba on the liposome surface was detectable by flow cytometric analysis. Addition of vWf and ristocetin caused specific agglutination of rGPIbalpha-liposomes, as evaluated by an aggregometer or a fluorescent microscopy. When ristocetin was added to platelet-rich plasma (PRP) pre-mixed with rhodamine-labeled rGPIbalpha-liposomes, platelets aggregated and rhodamine-fluorescence was strongly positive in the platelet thrombi, suggesting that heterologous aggregation (attachment of liposomes to platelets) occurred. Platelet aggregation in PRP at low platelet concentration (20-80 x 10(6)/ml) was enhanced by rGPIbalpha-liposomes in a dose-dependent manner. Thus, rGPIbalpha-liposomes may accumulate on vWf-exposed subendothelial tissues and enhance platelet function in vivo, supporting hemostasis in thrombocytopenic individuals.

Microwave Spectrum and Molecular Conformation of (E)-Benzaldehyde Oxime

The microwave spectrum of (E)-benzaldehyde oxime, C(6)H(5)-CH&dbond;NOH and C(6)H(5)-CH&dbond;NOD, has been observed in the frequency range from 26.5 to 40.0 GHz. The spectrum of the ground vibrational state was assigned and fitted to the Watson's A-reduced Hamiltonian to obtain these rotational and centrifugal distortion constants: A = 5183.13(29) MHz, B = 895.367(3) MHz, C = 763.819(3) MHz, Delta(J) = 0.019(3) kHz, and Delta(JK) = 0.204(7) kHz for the normal species, and A = 5158.4(23) MHz, B = 869.44(2) MHz, C = 744.34(2) MHz, Delta(J) = 0.023(2) kHz, and Delta(JK) = 0.193(7) kHz for the deuterated species. The values of the DeltaI (=I(c) - I(a) - I(b)) obtained for the normal and deuterated species were -0.295(6) and -0.28(5) a.m.u. Å(2), respectively. The molecular conformation of this molecule was a planar one in which the values of the dihedral angles, CCNO and CNOH, were almost 180 degrees and 180 degrees, respectively. Copyright 1999 Academic Press.

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

p16/MTS1/INK4A gene is frequently inactivated by hypermethylation in childhood acute lymphoblastic leukemia with 11q23 translocation

The p16 gene encoding a specific inhibitor of cyclin-dependent kinases 4 and 6 has been reported to be inactivated at a variety of rates in malignant tumors. We studied frequency and mechanism of inactivation of the p16 gene in various types of childhood acute lymphoblastic leukemia (ALL) using 36 leukemic cell lines established from children (B precursor-ALL, 28; B-ALL/Burkitt's lymphoma, 3; and T-ALL, 5). On Southern blot, homozygous deletions or hemizygous deletions with rearrangement were detected in 14 cell lines. The expression of p16 protein was not observed on Western blot in 18 of 22 cell lines with intact p16 gene, but induced in 16 cell lines after treatment with the demethylating agent, indicating the silencing of the p16 gene by hypermethylation. Of note, the p16 gene was inactivated by hypermethylation of the 5' CpG island in nine of nine cell lines with 11q23 translocation, but was restored with the treatment of the demethylating agent. Partial methylation of the p16 gene was also demonstrated in three of eight primary leukemia samples with this translocation, suggesting that the p16 gene inactivation by hypermethylation might play a role in the leukemogenesis and disease progression of ALL with 11q23 translocation.

Role of phosphorylation of Alzheimer's amyloid precursor protein during neuronal differentiation

Alzheimer's amyloid precursor protein (APP), the precursor of beta-amyloid (Abeta), is an integral membrane protein with a receptor-like structure. We recently demonstrated that the mature APP (mAPP; N- and O-glycosylated form) is phosphorylated at Thr668 (numbering for APP695 isoform), specifically in neurons. Phosphorylation of mAPP appears to occur during, and after, neuronal differentiation. Here we report that the phosphorylation of mAPP begins 48-72 hr after treatment of PC12 cells with NGF and that this correlates with the timing of neurite outgrowth. The phosphorylated form of APP is distributed in neurites and mostly in the growth cones of differentiating PC12 cells. PC12 cells stably expressing APP with Thr668Glu substitution showed remarkably reduced neurite extension after treatment with NGF. These observations suggest that the phosphorylated form of APP may play an important role in neurite outgrowth of differentiating neurons.

Intrapericardial organized hematoma. A rare complication after open heart surgery

Intrapericardial organized hematoma, which compresses cardiac chambers late after open heart surgery, is extremely rare. We report a case of intrapericardial organized hematoma in a 63-year-old man who underwent aortic valve replacement 8 years prior, which may have aggravated rheumatic mitral valve regurgitation compressing the mitral valve anulus. Under extracardiopulmonary bypass and cardioplegic heart arrest, we removed the hematoma and replaced the mitral valve with a 27 mm St. Jude Medical valve. There were no bleeding points on the heart and pericardium at operation and no history of blunt chest trauma. The etiology of the hematoma is uncertain.

Effect of temperature and mechanical strain on gastric epithelial cell line GSM06 wound restoration in vitro

BACKGROUND

The influence of the degree of cell differentiation and of physical stimulation on gastric mucosal wound healing is not completely understood.

METHODS

A gastric mucosal cell line, GSM06, derived from the gastric mucosal cells of transgenic mice harbouring the simian virus 40 large T antigen, was cultured at 33 degrees C to make a confluent cell sheet. Artificial wounds of constant size were created. Wound healing was monitored at different temperatures (33, 37 and 39 degrees C), which altered the degree of differentiation. Cell proliferation was detected by bromodeoxyuridine staining. Mechanical strain was applied to adherent GSM06 cells after wounding in order to increase their length by an average of 5 or 10% at 5 cycles/min for 60 h. Repair of the wound was monitored every 12 h.

RESULTS

Differentiated gastric epithelial cells showed a higher speed of migration. The number of proliferating cells around the wound was greatest at 33 degrees C and barely detectable at 39 degrees C. Under conditions of mechanical strain, the migration speed of differentiated cells (at 39 degrees C) slowed in a strain strength-dependent manner.

CONCLUSIONS

It is suggested that cell differentiation status and physical stimulants might play a role in gastric wound healing in vivo by modifying cellular migration.