[Detection of specific antibodies in saliva of patients with chronic schistosomiasis japonica]

OBJECTIVE

To investigate the feasibility of detecting specific antibodies in the saliva of schistosomiasis patients.

METHODS

Specific antibodies in saliva samples of 32 schistosomiasis patients and 140 normal individuals were detected by using ELISA and the results were compared with those detected for specific antibodies in serum.

RESULTS

The sensitivity and specificity of the ELISA were 90.6% and 94.4%, respectively, being slightly lower than that of the 100% sensitivity and 96.2% specificity for the serum. No significant difference between them was found (P > 0.05).

CONCLUSION

Detecting specific antibodies in saliva can be used for immunodiagnosis of schistosomiasis japonica as a noninvasive method in field surveys.

[The diagnostic value of combined detection of circulating antigens and antibodies in urine of patients with schistosomiasis japonica]

OBJECTIVE

To assess the value of detecting circulating antigens and antibodies in urine as a noninvasive method for the diagnosis of schistosomiasis.

METHODS

A sandwich ELISA and ELISA using McAb were applied to detect circulating schistosomal antigens and specific antibodies in the urine of patients with acute and chronic schistosomiasis.

RESULTS

When the urine samples from 10 cases of acute schistosomiasis and 61 cases of chronic schistosomiasis were examined, the positive rates of circulating antigens and specific antibodies were 60%, 40%, and 80%, 60.1%, respectively; when both detection was combined, the positive rates were 100% and 71.7% respectively, whereas a false positive rate of 3% of CAg or CAb was detected in the urine of 100 normal controls.

CONCLUSION

The detection of circulating antigen in urine is a practicable and noninvasive method for the diagnosis of schistosomiasis.

In vivo pyruvate detected by MR spectroscopy in neonatal pyruvate dehydrogenase deficiency

We present a unique finding of an elevated level of pyruvate at 2.37 ppm revealed by in vivo MR spectroscopy of a female neonate. Low fibroblast pyruvate dehydrogenase (PDH) complex activity subsequently confirmed a diagnosis of PDH deficiency. Abnormalities of brain development consistent with PDH deficiency were also evident on fetal and postnatal MR images. To our knowledge, this is the first report of pyruvate being shown in vivo in a child and the first report of MR spectroscopy aiding in the diagnosis of inborn error in pyruvate metabolism before confirmation by conventional enzymatic testing. This finding has potential implications for earlier diagnosis in patients with defects in mitochondrial metabolism.

Chromosomal polymorphism of mandarin vole, Microtus mandarinus (Rodentia)

The mitotic and meiotic chromosomes of mandarin vole, Microtus mandarinus Milne-Edwards, from Shandong Province of China were analyzed by conventional, G- and C-banding and Silver-staining techniques. We detected chromosomal polymorphism in the vole, exhibiting diploid chromosome numbers 2n = 48-50 and variable morphology of the 1st pair, one medium sized telocentric pair and the X chromosomes. Four types of karyotypes were revealed in the population. According to banding analysis, there were pericentric inversion, Robertsonian fusion and translocation in M. mandarinus karyotype evolution. The X displayed two different morphologies, which could be explained by prericentric inversion and a telocentric autosome translocation.

The transportation, time-dependent distribution of heavy metals in paddy crops

Sixteen experimenmtal plots (5 m x 6 m = 30 m2) were designed with four different levels of heavy metals (HMs) concentration in soil. The concentrations of heavy metals in soils, and paddy plant during the different periods of growth were investigated. A relationship between the total HM content in plants and the HM level in soil was found for a wide range of concentrations. The exchangeable fraction of HMs extracted with 1 M MgCl2 solution according to Tessier's method increased correlation with the dosage of supplemented HMs, then decreased as time went on. The time-related variation of exchangeable HMs in soil demonstrated that the amount of effective HMs taken up by paddy differed at various growth phases. The amount of HMs accumulated in different parts of paddy followed the order of root > stem > grain, leaf. The transportation potential of the HMs in paddy in present study followed the order of Zn, Cr > Cd, Cu > Pb. The HM content in root, stem and leaf of paddy plant (dry weight) was low at time of seedling. The concentration in the root increased sharply at time of tillering, decreased thereafter. The concentrations in stem and leaf reached the highest at time of tillering, then decreased, while rose slightly at following time.

Phosphine and methane generation by the addition of organic compounds containing carbon-phosphorus bonds into incubated soil

Formation of phosphine and methane in anaerobic incubation systems was investigated under stirred and unstirred conditions. The PH3 and CH4 levels in the headspace, as well as the matrix-bound PH3 content in the stirred soil, significantly increased upon the addition of phosphonoacetic acid (P(O)(OH)2CH2COOH). Both the levels of matrix-bound PH3 and CH4 are positively correlated to the buffered dithionite fraction of reactive phosphorus in the soil samples, while a negative correlation was observed between matrix-bound PH3/CH4 levels and the reactive phosphorus fraction.

The effect of fulvic acid on the dose effect of selenite on the growth of wheat

The effect of fulvic acid on the dose effect of selenite has been studied by using the hydroponics culture of wheat in the presence of selenite and fulvic acid (FA). The bioavailability of Se was investigated by 5 morphological end points and 12 biological and biochemical end points at different phases of growth of wheat seedling and seed germination. The "platform" of the dose effect observed indicates that the presence of FA can have both the beneficial effects and antagonists on the toxicity of Se to a certain extent.

Proton magnetic resonance spectroscopy of brain metabolites in galactosemia

Brain edema may occur in infants with galactosemia and has been associated with accumulation of galactitol. Proton magnetic resonance spectra were obtained from 12 patients (four newly diagnosed neonates and eight patients on galactose-restricted diets, age range 1.7-47 years) and control subjects to measure brain galactitol levels in vivo and correlate them with urinary galactitol excretion. The results demonstrate that a markedly elevated brain galactitol level may be present only in newborn infants with galactosemia who exhibit massive urinary galactitol excretion.

Synthesis and properties of 9,9-diarylfluorene-based triaryldiamines

[reaction: see text] 9,9-Diaryl-2,7-dibromofluorene was synthesized by a triflic acid promoted Friedel-Crafts reaction. Introduction of diarylamino groups at its C2 and C7 positions by a Pd-catalyzed amination results in the formation of a novel class of triaryldiamines. The 9,9-diaryl substituents at the central linkage play a less important role in the photophyscial properties but affect the oxidation potential and improve the morphological stability of these new triarylamines.

Aromatase (Cyp19) expression is up-regulated by targeted disruption of Dax1

DAX-1 [dosage-sensitive sex reversal, adrenal hypoplasia congenita (AHC) critical region on the X chromosome, gene 1] is an orphan nuclear receptor that represses transcription by steroidogenic factor-1 (SF-1), a factor that regulates expression of multiple steroidogenic enzymes and other genes involved in reproduction. Mutations in the human DAX1 gene (also known as AHC) cause the X-linked syndrome AHC, a disorder that is associated with hypogonadotropic hypogonadism also. Characterization of Dax1-deficient male mice revealed primary testicular defects that included Leydig cell hyperplasia (LCH) and progressive degeneration of the germinal epithelium, leading to infertility. In this study, we investigated the effect of Dax1 disruption on the expression profile of various steroidogenic enzyme genes in Leydig cells isolated from Dax1-deficient male mice. Expression of the aromatase (Cyp19) gene, which encodes the enzyme that converts testosterone to estradiol, was increased significantly in the Leydig cells isolated from mutant mice, whereas the expression of other proteins (e.g., StAR and Cyp11a) was not altered. In in vitro transfection studies, DAX-1 repressed the SF-1-mediated transactivation of the Cyp19 promoter but did not inhibit the StAR or Cyp11a promoters. Elevated Cyp19 expression was accompanied by increased intratesticular levels of estradiol. Administration of tamoxifen, a selective estrogen-receptor modulator, restored fertility to the Dax1-deficient male mice and partially corrected LCH, suggesting that estrogen excess contributes to LCH and infertility. Based on these in vivo and in vitro analyses, aromatase seems to be a physiologic target of Dax-1 in Leydig cells, and increased Cyp19 expression may account, in part, for the infertility and LCH in Dax1-deficient mice.

Time-dependent apoptotic development and pro-apoptotic genes expression in rat heart after myocardial infarction

We investigated the apoptotic development and apoptotic-related gene expression after myocardial infarction (MI) at different time points in the current study. Bax gene expression was increased at 12 h after MI and peaked at 24 h. Fas gene started to over-express at 12 h after MI as well but it reached maximum at 72 h. In the MI groups, strongest staining of apoptosis was detected in rats 3 days post operation. Our results demonstrate that apoptotic development after MI is time dependent in the ischemic area and there could be some linkage with the over expression of angiotensin II receptors post MI.

Sertoli cell-specific rescue of fertility, but not testicular pathology, in Dax1 (Ahch)-deficient male mice

DAX1 is an orphan member of the nuclear hormone receptor superfamily of transcription factors. Our recent characterization of Dax1 (Ahch)-deficient male mice revealed a primary testicular defect resulting in hypogonadism and sterility. The progressive degeneration of the germinal epithelium, independent of abnormal gonadotropin and testosterone production, suggested an intrinsic loss of Dax1 function in the Sertoli cells. To test this hypothesis, we assessed the effect of Sertoli cell-specific expression of a human DAX1 (AHC) transgene driven using the promoter of the Müllerian inhibiting substance (MIS) gene. The MIS-DAX1 transgene partially rescued the mutant phenotype of the Dax1-deficient male mice. Although testicular morphology remained abnormal, fertility was restored to levels matching that of wild-type littermates. Examination of several markers of sperm fertilizing capability revealed significant improvements in MIS-DAX1-rescued mice. Epididymal sperm count and sperm motility were greater in 12-week-old rescued mice than in age-matched Dax1-deficient mice. The ability of sperm to undergo an immediate acrosome reaction was impaired in Dax1-deficient animals, and sperm from Dax1-deficient mice fertilized only 8.2 +/- 6.8% of eggs in vitro, significantly less than rescue (67.8 +/- 19.1%) and wild-type (88.9 +/- 3.9%) sperm. These results indicate that Dax1 expression in Sertoli cells is adequate to overcome crucial thresholds related to sperm production and function. However, the failure to completely rescue the testicular pathology of Dax1-deficient mice suggests that Dax1 expression in other somatic cells is essential for normal testicular development.

Utilization of dental services in Southern China

A population's utilization of dental services is an important parameter in oral health care planning, which has rarely been studied in China. The objectives of this report were to describe the dental service utilization pattern of middle-aged and elderly Chinese and to analyze the influence of selected variables on the use of dental services. A Guangdong Province population of 1,573 35- to 44-year-olds and 1,515 65- to 74-year-olds recruited from urban and rural communities was interviewed in their local dialect. It was found that 23% of the middle-aged and 24% of the elderly subjects had visited a dentist within the preceding year. The two most commonly cited reasons for not having seen a dentist for at least 3 years were: no perceived need, and no serious dental problems. Among subjects who had visited a dentist within 3 years, the 3 most commonly received treatments were: fillings, extractions, and dental prostheses. Furthermore, a logistic regression analysis showed that women, subjects who lived in urban areas, were better educated, were wealthier, and had better oral health knowledge were more likely to be a recent dental service user. In conclusion, dental service utilization among the adult Southern Chinese was found to be low, problem-driven, and influenced by some socio-economic factors.

An Oral Health Survey in Southern China, 1997: background and methodology

Relatively limited information is available about the oral health in the Guangdong Province of Southern China, the closest neighbor to Hong Kong. The study intended to explore the oral health status, knowledge, attitudes, and dental care utilization in the Guangdong population as a basis for formulating strategies for oral health prevention and treatment. Through multi-stage stratified and quota-sampling, individuals from urban as well as rural communities were selected (5- to 6-; 12-; 35- to 44-; and 65- to 74-year-olds; total N = 6251). Structured interviews and clinical examinations were performed. Inter-examiner reliability was high (kappa = 0.60-0.96). Samples of community water were taken for fluoride assessment. Overall, the sample surveyed was acceptably representative of the population, with some under-representation of rural residents and agricultural workers. Re-weighting was performed in appropriate analyses. The data analysis model used in the Second International Collaborative Study was used as a guide for the present data analysis. This approach has not previously been used on a Mainland Chinese population.

Oral health knowledge, attitudes, and practices of Chinese adults

Only recently have behavioral aspects been taken into consideration in oral health studies in China; thus, relevant information on perceptions in adult Chinese about oral health care is inadequate. In 1996-97, a large-scale oral epidemiological study was conducted in Southern China. Among its objectives were to describe the oral health knowledge, attitudes, and practices of the urban and rural adults living in Southern China and to analyze the influence of selected demographic and socio-economic factors. From 8 urban and 8 rural communities in Guangdong Province, 1,573 35- to 44-year-olds and 1,515 65- to 74-year-olds were sampled. Specially trained interviewers from the staff of local government or hospitals conducted face-to-face structured interviews. Almost all of the middle-aged and more than 90% of the dentate elderly surveyed claimed that they brushed their teeth every day and used toothpaste during toothbrushing, but awareness about fluoride content was lacking. The respondents had poor oral health knowledge but positive attitudes toward oral health, providing a basis for more community-based oral health education programs, especially targeting adults who are less-well-educated and have fewer socio-economic advantages.

Low allicin release from garlic supplements: a major problem due to the sensitivities of alliinase activity

Most garlic supplements are standardized on allicin potential and are enteric-coated to prevent gastric acid inactivation of the allicin-producing enzyme, alliinase. To determine whether these products release the claimed amount of allicin under simulated gastrointestinal conditions, USP dissolution method 724A for drug release was applied to all 24 known brands of enteric-coated tablets. It was found that nearly all brands employed effective coatings and that they met their claims for allicin potential when crushed and suspended in water. However, all brands except one gave low dissolution allicin release, with 83% of the brands releasing less than 15% of their potential. The low allicin release was found to be due to both impaired alliinase activity, mostly caused by tablet excipients, and to slow tablet disintegration, which also impairs alliinase activity. Only when tablets had high alliinase activity and disintegrated rapidly did they show high allicin release. The ability of USP 724A to estimate allicin release in vivo was validated by monitoring breath levels of the allicin metabolite, allyl methyl sulfide. In conclusion, garlic powder supplements should no longer be standardized on allicin potential, but rather on dissolution allicin release.

[Effects of nutrition condition on pcDNA3-HBS plasmid DNA production]

To investigate the effects of nutrition condition on plasmid DNA production, Escherichia coli JM109 containing plasmid pcDNA3S-HBA was grown in different culture media. Results show that carbon source, nitrogen source affected plasmid DNA yield significantly. Glucose and peptone was selected, since they were preferable to other investigated carbon source and nitrogen source. In M9P medium, the appropriate concentration of(NH4)2SO4 was important for plasmid DNA production, Gly, Asp, Gln were formulated into the M9G medium because they served as the nitrogen donors for nucleotides synthesis. With addition of 1.2 g/L Asp, 1.0 g/L Gln and 0.4 g/L Gly into M9G medium, plasmid DNA yield was 25 mg/L after 20 h culture. Foreign nucleotides distinctively affected plasmid DNA production. With addition of 0.4 g/L nucleosides mixture of thymidine and cytidine(moles fraction of thymidine:cytidine = 1:1) into M9P medium, plasmid DNA yield was 35 mg/L.

Allicin release under simulated gastrointestinal conditions from garlic powder tablets employed in clinical trials on serum cholesterol

The failure of five recent clinical trials to show significant reduction in elevated serum cholesterol by a single brand of allicin-standardized garlic powder tablets is in contrast to many prior positive studies with the same brand. The hypocholesterolemic activity of garlic is mainly due to allicin, a compound that is produced by the acid-sensitive garlic enzyme, alliinase, only after tablet consumption. Therefore, the allicin-releasing ability of ten lots of these tablets--manufactured over the same years that the positive and negative clinical trials were conducted (1989-1997)--was determined under simulated gastrointestinal dissolution conditions, as defined by U.S. Pharmacopeia Method 724A. It was found that the older lots were more resistant to acid-disintegration (2.5 h vs. 1.3 h, P < 0.001) and that they released three times as much allicin (44% vs. 15 % of their potential, P < 0.001) as the newer lots. A second brand of tablets employed in a recent negative trial released no detectable amount of allicin, while a third set of tablets with high allicin release was used in a trial that gave positive effects. Hence, the persons involved in the recent negative clinical trials probably received considerably less allicin than did those in the older positive studies, possibly accounting for much of the discrepancy in the outcomes. In conclusion, clinical trials using garlic powder tablets to assess any effect of garlic that might be related to allicin, as most are, cannot be considered valid for garlic when the trial shows no effect, unless the expected allicin release from the tablets has at least been determined under standardized drug release conditions (USP 724A).

MR spectroscopy in pediatric neuroradiology

MR spectroscopy of the pediatric brain now has entered the clinical arena as a result of enhanced technology, complementary new sequences, and proof of clinical utility. Armed with a knowledge of the variation in metabolite concentrations over time, with myelination and brain growth, proton MR spectroscopy can be helpful in differential diagnosis, management, and prognostication of pediatric disease processes. Although other molecules can be interrogated, hydrogen proton spectroscopy is the mainstay. The development of multiplanar techniques, performed in a time-efficient fashion, has enabled more robust spectra to be obtained from larger volumes of brain, permitting spatial localization of different metabolites, such as lactate. With the introduction of gene therapy and other new interventions, a noninvasive tool such as MR spectroscopy may prove to be invaluable.

[Experimental research on inhibitory effect of alcohol extracts from Loranthus yadoriki Sieb. on coxsackie B3 virus]

OBJECTIVE

To investigate the antiviral effect of two components (B and C) in the alcohol extracts from Loranthus yadoriki Sieb for development of new antiviral drugs for coxsackie B3 virus(CVB3).

METHOD

Using ribavirin as positive control, the plaque reduction assay was adopted for pharmadynamic detection.

RESULTS

In the HEp-2 cell system, with respect to direct virucidal activity and the inhibition on CVB3 infection and multiplication, ED50s of component B were 2.32 micrograms.ml-1, 0.24 microgram.ml-1 and 1.91 micrograms.ml-1, respectively and those of component C, 1.44 micrograms.ml-1, 2.06 micrograms.ml-1 and 3.70 micrograms.ml-1 respectively. For the inhibition on multiplication of CVB3, ED50 of ribavirin was 7.55 micrograms.ml-1.

CONCLUSION

Treatment indexes (TI) of the direct virucidal activity and inhibitory effects of component B on CVB3 infection and multiplication 22.6, 219 and 27.5 respectively; component C, 115, 165 and 21.6; inhibition of ribavirin on CVB3 is 38, which is comparable to those of components B and C. It is thus suggested that the anti-CVB3 action of components B and C in the alcohol extracts from Loranthus yadoriki Sieb deserves to be exploited.

[Triterpenoid compounds of Prunella genus and their features of 13C NMR spectroscopy]

OBJECTIVE

To summarize the research advances and 13C NMR features of triterpenoid compounds in the plant of Prunella genus.

METHODS

Consulting related literatures and summing up the triterpenoid compounds and their features of 13C NMR spectra.

RESULT AND CONCLUSION

Up to now, 28 triterpenoid compounds were isolated from the plant of P. genus. of which 20 were in free state and 8 were triterpenoid saponins. The 13C NMR spectra of different triterpenoids showed different features in respects such as skeletons, substituent groups and positions.

Study on the dose-effect relationship of selenite with the growth of wheat

The wheat in hydroponics culture has been chosen as a model to study the dose-effect relationship of selenite with its growth. Five different morphological end points and 12 different biological and biochemical end points during different phases of growth of wheat seedling and seed germination have been measured and analyzed. A dose-effect relationship of selenite with the growth of wheat has been obtained from data analysis. The results shows that critical threshold for beneficial effect is about 1.0 mg Se/L, and the critical threshold for adverse effect is about 5.0 mg Se/L in hydroponics culture. From the result of product of lipid peroxidation, it is assumed that the role of selenium for plant is related to the oxy-radical reaction.

Allelic imbalance at the LKB1 (STK11) locus in tumours from patients with Peutz-Jeghers' syndrome provides evidence for a hamartoma-(adenoma)-carcinoma sequence

Patients with Peutz-Jeghers' syndrome (PJS) develop hamartomatous gastrointestinal polyps and characteristic pigmentation, as a result of germline mutations in the LKB1 gene. The hamartomas in PJS were long considered to be without malignant potential. There is, however, accumulating epidemiological evidence to suggest that PJS predisposes to cancers at several different sites (colon, pancreas, breast, ovary, testis, and cervix), although large enough patient samples are rarely available to prove this. Allelic imbalance [allele loss, loss of heterozygosity (LOH)] has previously been reported in a small number of PJS polyps, suggesting that LKB1 acts as a tumour suppressor in these tumours. This study confirms allelic loss at LKB1 in PJS polyps and shows that LOH also occurs in cancers of the colon, breast, and cervix in PJS patients. Allele loss was additionally found in a colonic adenoma from a PJS patient, strongly suggesting the existence of a hamartoma-(adenoma)-carcinoma sequence in tumourigenesis. These results provide molecular evidence that PJS patients are predisposed to cancers at several sites, as a direct result of selection for loss of the 'wild-type' LKB1 allele in tumours. Given the rare involvement of LKB1 in sporadic cancers, these data also suggest that the indirect effect on cancer risk (or 'bystander effect') proposed for hamartomas in juvenile polyposis does not apply to carcinomas in PJS.

Spectrum of the fokker-planck operator representing diffusion in a random velocity field

We study spectral properties of the Fokker-Planck operator that represents particles moving via a combination of diffusion and advection in a time-independent random velocity field, presenting in detail work outlined elsewhere [J. T. Chalker and Z. J. Wang, Phys. Rev. Lett. 79, 1797 (1997)]. We calculate analytically the ensemble-averaged one-particle Green function and the eigenvalue density for this Fokker-Planck operator, using a diagrammatic expansion developed for resolvents of non-Hermitian random operators, together with a mean-field approximation (the self-consistent Born approximation) which is well controlled in the weak-disorder regime for dimension d>2. The eigenvalue density in the complex plane is nonzero within a wedge that encloses the negative real axis. Particle motion is diffusive at long times, but for short times we find a novel time dependence of the mean-square displacement, <r(2)> approximately t(2/d) in dimension d>2, associated with the imaginary parts of eigenvalues.

Antimicrobial activity of synthetic all-D mastoparan M

Mastoparan M, a tetradecapeptide toxin (INKAIAALAKKLL-NH2) from hornet venom and its D-form mastoparan M were synthesized chemically. All D- and L-mastoparan M forms were found to adopt 28% alpha-helical structures in a 30% trifluroethanol solution as shown by the circular dichroism spectrum. All-D mastoparan M caused 3H-thymidine release from labeled bacterial cells after incubation for 1 h and complete cell lysis by 4 h. Both L- and D-mastoparan M showed strong activity against gram-positive and gram-negative bacteria. All-D mastoparan M showed 2-fold higher antibacterial activity than L-mastoparan M. The effects of all-D mastoparan M on the surface morphology of Staphylococcus aureus (ATCC29213) and Escherichia coli (ATCC25922) were studied by scanning-beam electron microscopy. Blast-like bleb extrusions on the surface of some S. aureus and swellings on the end of E. coli were seen after culture with all-D mastoparan M. These findings indicated the all-D mastoparan M could kill bacteria by disrupting cells.

Pharmacokinetics, tissue distribution and photodynamic therapy efficacy of liposomal-delivered hypocrellin A, a potential photosensitizer for tumor therapy

Hypocrellin A, from Hypocrella bambusae, is a novel photosensitizer of high singlet oxygen quantum yield for photodynamic therapy (PDT). Tissue distributions were studied in tumor-bearing mice as a function of time following administration. The tumor model was S-180 sarcoma transplanted into one hind leg of male Kunming mice; hypocrellin A (HA) was delivered to the mice by intravenous injection of 5 mg/kg of body weight as a suspension either as a unilamellar liposome or in dimethyl sulfoxide (DMSO)-solubilized saline. The HA was isolated from several tissues and organs, as well as tumors and peritumoral muscles and skin. Quantitation was performed by a high-performance liquid chromatographic technique with detection that utilizes the native fluorescence of HA. Independent of the delivery system, the dye was retained in tumors at higher concentrations than in normal tissues, except for kidney, liver, lung and spleen. The dye retention in tumors was high and was vehicle dependent. For the liposomal system, the maximal accumulation in tumor and maximal ratios of dye in tumor versus peritumoral muscle and skin occurred 12 h postinjection; for the DMSO saline system, the maximal ratio occurred earlier, 6 h postadministration. Liposomal delivery improved the selective accumulation of the dye in tumor with higher maximal levels in tumor and higher ratios of tumor-to-muscle and tumor-to-skin. Levels of dye were very low or not detectable in the brain. The PDT efficacy of HA in the liposome and DMSO saline systems was determined by evaluating the tumor volume regression percent. The PDT efficacy of HA in liposomes was highest when light treatment was performed at 12 h postinjection, consistent with the highest retention of HA in tumors. Similarly, the maximal PDT efficacy in DMSO saline was attained at 6 h postinjection, the highest HA retention point in tumor. Moreover, the peak PDT efficacy of HA in liposomes was much higher than that of HA in DMSO saline and even hematoporphyrin monomethylether.

Study of the incorporation of selenium into peroxidase isozyme of wheat seedling

The effects of selenium on the activity of peroxidase (POD) of wheat seedling and its isozyme pattern were studied using a greenhouse hydroponic experiment. The results show that the activity of POD is increased in response to higher Se concentration (approx 5.0 mg/L) in culture medium. The electrophoretic pattern of the POD isozyme was altered by growth of the wheat in a selenium medium. Se could incorporate into some POD isozymes during either seed germination or the seedling growth period. There is a dose-responsive incorporation of selenium in isozyme of POD and selenium content in the isozyme increase along with the increase of selenium concentration in the medium.

Magnetic resonance imaging measurement of volume magnetic susceptibility using a boundary condition

A magnetic resonance imaging method is described for measuring the magnetic susceptibility difference between two homogeneous macroscopic compartments in contact with each other. A boundary condition is derived for the interface of the two compartments. This boundary condition predicts that across the interface there is a resonant frequency jump, which is a function of interfacial orientation relative to B0 field and the difference in susceptibility of the two sides. Based on this relationship, the magnetic susceptibility difference between two materials can be obtained from MR gradient echo imaging using signals from both sides in the vicinity of the boundary. This method is demonstrated by solution phantom experiments.

Three-dimensional multivoxel proton MR spectroscopy of the brain in children with neurofibromatosis type 1

BACKGROUND AND PURPOSE

Neurofibromatosis type 1 (NF1), the most common autosomal dominant genetic disorder, frequently manifests as focal areas of signal intensity (FASI) on T2-weighted MR images. The purpose of our study was to investigate whether tumor(s), focal areas of signal intensity (FASI), and normal brain can be differentiated by using 3D multivoxel localized proton MR spectroscopy in children with neurofibromatosis type 1 (NF1) disorder.

METHODS

Five children with NF1 and two healthy control subjects, all in the 3- to 11-year-old age group, were studied with a new 3D proton MR spectroscopy technique: a hybrid of 1D fourth-order transverse Hadamard spectroscopic imaging and 2D chemical shift imaging. A 3D volume-of-interest (VOI) was image-guided onto the site of the abnormality and identified on three orthogonal images. Proton MR spectroscopy partitioned the VOI into 6 x 6 x 4 (or 8 x 8 x 4) voxels, 1.5 (or 1.0) cm3 each.

RESULTS

Simultaneous coverage of the entire VOI yielded good spectral signal-to-noise ratio from 136 (or 256) voxels in 27 minutes. Proton MR spectroscopy indicated that FASI a) are characterized by significantly elevated choline (Cho), reduced creatine (Cr), 2>Cho: Cr>1.3, and near normal N-acetylaspartate (NAA) levels; b) are different from tumors that exhibit Cho:Cr>2 and no NAA; c) have no intrinsic lipid or lactate signal(s); and d) correlate in spatial extent but are more extensive than indicated by MR imaging.

CONCLUSION

Three-dimensional multivoxel proton MR spectroscopy reveals distinct metabolic features that differentiate normal, FASI, and tumor regions in the pediatric brain.

In vivo brain myo-inositol levels in children with Down syndrome

The Na+/myo-inositol cotransporter (SLC5A3) gene, located on the long arm of human chromosome 21, may play a key role in osmoregulation including the regulation of levels of the "idiogenic osmole," myo-inositol, in brain cells. To determine whether the levels of myo-inositol are increased in the basal ganglia of children with Down syndrome, we performed in vivo brain hydrogen 1-nuclear magnetic resonance or 1H-magnetic resonance spectroscopy and measured plasma osmolality in a cohort of children with trisomy 21. Myo-inositol is elevated in the corpus striatum of infants and children with Down syndrome, even in the absence of hypertonic stress.

Germline mutations of the LKB1 (STK11) gene in Peutz-Jeghers patients

Germline mutations of the LKB1 (STK11) serine/threonine kinase gene (chromosome 19p13.3) cause Peutz-Jeghers syndrome, which is characterised by hamartomas of the gastrointestinal tract and typical pigmentation. Peutz-Jeghers syndrome carries an overall risk of cancer that may be up to 20 times that of the general population. Here, we report the results of a screen for germline LKB1 mutations by DNA sequencing in 12 Peutz-Jeghers patients (three sporadic and nine familial cases). Mutations were found in seven (58%) cases, in exons 1, 2, 4, 6, and 9. Five of these mutations, two of which are identical, are predicted to lead to a truncated protein (three frameshifts, two nonsense changes). A further mutation is an in frame deletion of 6 bp, resulting in a deletion of lysine and asparagine; the second of these amino acids is conserved between species. The seventh mutation is a missense change in exon 2, converting lysine to arginine, affecting non-conserved amino acids and of uncertain functional significance. Despite the fact that Peutz-Jeghers syndrome is usually an early onset disease with characteristic clinical features, predictive and diagnostic testing for LKB1 mutations will be useful for selected patients in both familial and non-familial contexts.

Allelic imbalance at the LKB1 (STK11) locus in tumours from patients with Peutz-Jeghers' syndrome provides evidence for a hamartoma-(adenoma)-carcinoma sequence

Patients with Peutz-Jeghers' syndrome (PJS) develop hamartomatous gastrointestinal polyps and characteristic pigmentation, as a result of germline mutations in the LKB1 gene. The hamartomas in PJS were long considered to be without malignant potential. There is, however, accumulating epidemiological evidence to suggest that PJS predisposes to cancers at several different sites (colon, pancreas, breast, ovary, testis, and cervix), although large enough patient samples are rarely available to prove this. Allelic imbalance [allele loss, loss of heterozygosity (LOH)] has previously been reported in a small number of PJS polyps, suggesting that LKB1 acts as a tumour suppressor in these tumours. This study confirms allelic loss at LKB1 in PJS polyps and shows that LOH also occurs in cancers of the colon, breast, and cervix in PJS patients. Allele loss was additionally found in a colonic adenoma from a PJS patient, strongly suggesting the existence of a hamartoma-(adenoma)-carcinoma sequence in tumourigenesis. These results provide molecular evidence that PJS patients are predisposed to cancers at several sites, as a direct result of selection for loss of the 'wild-type' LKB1 allele in tumours. Given the rare involvement of LKB1 in sporadic cancers, these data also suggest that the indirect effect on cancer risk (or 'bystander effect') proposed for hamartomas in juvenile polyposis does not apply to carcinomas in PJS.

Allele loss and mutation screen at the Peutz-Jeghers (LKB1) locus (19p13.3) in sporadic ovarian tumours

Germline mutations in the LKB1 (STK11) gene (chromosome sub-band 19p13.3) cause characteristic hamartomas and pigmentation to develop in patients with Peutz-Jeghers syndrome. Peutz-Jeghers syndrome carries an overall risk of cancer that may be up to 20 times that of the general population and Peutz-Jeghers patients are at increased risk of benign and malignant ovarian tumours, particularly granulosa cell tumours. Loss of heterozygosity (allele loss, LOH) has been reported in about 50% of ovarian cancers on 19p13.3. LKB1 is therefore a candidate tumour suppressor gene for sporadic ovarian tumours. We found allele loss at the marker D19S886 (19p13.3) in 12 of 49 (24%) sporadic ovarian adenocarcinomas. Using SSCP analysis, we screened ten ovarian cancers with LOH, 35 other ovarian cancers and 12 granulosa cell tumours of the ovary for somatic mutations in LKB1. No variants were detected in any of the adenocarcinomas. Two mutations were detected in one of the granulosa cell tumours: a mis-sense mutation affecting the putative 'start' codon (ATG --> ACG, M1T); and a silent change in exon 7 (CTT --> CTA, leucine). Like BRCA1 and BRCA2, therefore, it appears that LKB1 mutations can cause ovarian tumours when present in the germline, but occur rarely in the soma. The allele loss on 19p13.3 in ovarian cancers almost certainly targets a different gene from LKB1.

The role of humic substances in drinking water in Kashin-Beck disease in China

We conducted in vitro and in vivo assays in a selenium-deficient system to determine if organic matter (mainly fulvic acid; FA) is involved in a free radical mechanism of action for Kashin-Beck disease. Cartilage cell culture experiments indicated that the oxy or hydroxy functional groups in FA may interfere with the cell membrane and result in enhancement of lipid peroxidation. Experiments with rats demonstrated that toxicity from FA was reduced when the hydroxy group was blocked. Induction of lipid peroxidation by FA in liver and blood of rats was similar to that exhibited by acetyl phenyl hydrazine. FA accumulated in bone and cartilage, where selenium rarely concentrates. In addition, selenium supplementation in rats' drinking water inhibited the generation of oxy-free radicals in bone. We hypothesized that FA in drinking water is an etiological factor of Kashin-Beck disease and that the mechanism of action involves the oxy and hydroxy groups in FA for the generation of free radicals. Selenium was confirmed to be a preventive factor for Kashin-Beck disease.

Proton MR spectroscopy of pediatric brain metabolic disorders

Brain metabolic disorders are a major cause of mortality and morbidity in children. Proton MR spectroscopy is a sensitive diagnostic modality for these diseases. The abnormalities in metabolite levels revealed by MR spectroscopy provide specific information in a wide range of metabolic disturbances. Continuing MR imaging and MR spectroscopy yields maximum diagnostic information in an MR examination.

Stress-induced secretion of growth inhibitors: a novel tumor suppressor function of p53

p53 tumor suppressor gene controls cell response to a variety of stresses inducing growth arrest or apoptosis in damaged cells. It largely determines the sensitivity of tumor and normal cells to radiation and chemotherapy, and, therefore, defines both the efficacy and limitations of anti-cancer treatment. To determine molecular mechanisms of p53-dependent stress response in normal tissues we identified and compared the spectra of radiation-responsive genes in cells of different origin and p53 status using a cDNA array hybridization technique. The majority of genes identified were p53-dependent and cell type specific. Several of the new p53 responders encode known secreted growth inhibitory factors. This suggests that p53, in addition to its intrinsic antiproliferation activity, can cause 'bystander effect' by inducing export of growth suppressive stimuli from damaged cells to neighboring cells. Consistently, a p53-dependent accumulation of factors, which causes growth inhibitory effects in a variety of cell lines, was found after gamma irradiation in the media from established and primary cell cultures and in the urine of irradiated mice. Moreover, p53-dependent factors released by normal human fibroblasts potentiated the cytotoxic effect of a chemotherapeutic drug on co-cultivated tumor cells. This suggests a previously unknown role for normal cells in chemo- and radiation therapy of cancer.

Genetic pathways of colorectal carcinogenesis rarely involve the PTEN and LKB1 genes outside the inherited hamartoma syndromes

Germline mutations of the PTEN/MMAC1/TEP and LKB1 genes cause hamartomas to develop in the gastrointestinal tracts of patients with Cowden syndrome and Peutz-Jeghers syndrome, respectively. PTEN mutations may also be responsible for some cases of juvenile polyposis. Histologically, hamartomas appear benign, but there is good evidence that in these syndromes, the hamartomas can progress to colorectal carcinoma. It remains unknown whether or not cancers that develop from hamartomas acquire a spectrum of mutations similar to those in sporadic colon cancers. PTEN and LKB1 are candidate genes for mutations in sporadic colon cancers, either as initiating events in tumorigenesis or providing a selective advantage during tumor growth. Using single-strand conformational polymorphism analysis, we have screened a set of sporadic colon cancers for somatic mutations in PTEN and LKB1. No variants predicted to alter protein function were detected in LKB1, but 1 of 72 cancers showed a somatic mutation in PTEN, together with allele loss. This cancer did not have a detectable APC mutation or allele loss at APC. It remains possible that PTEN and LKB1 are inactivated in other sporadic colon cancers by means such as deletion or promoter methylation. Like BRCA1 and BRCA2, however, it appears that PTEN and LKB1 mutations can cause cancers when present in the germline, but occur rarely in the soma.

Imaging studies in a unique familial dysmyelinating disorder

We report the imaging findings in five patients with a unique dysmyelinating disorder. MR studies of these infants showed obstructive hydrocephalus caused by mass effect produced by an enlarged cerebellum. The white matter of an enlarged cerebrum and cerebellum showed delayed myelination. Proton spectroscopy showed normal N-acetylaspartate (NAA) levels. While the dysmyelinating disorder was clearly differentiated from Canavan disease by an absence of elevated NAA and differing histopathologic findings and autosomal-dominant inheritance pattern, there were similarities to this disease in the presentation and, to some extent, in the initial imaging findings.

1H MR spectroscopy of the basal ganglia in childhood: a semiquantitative analysis

Proton MR spectra of the basal ganglia were obtained from 28 patients, 24 male and 14 female, median age 16.3 months (5 weeks to 31 years). They included 17 patients with normal MRI of the basal ganglia without metabolic disturbance (control group) and 11 patients with various metabolic diseases: one case each of high serum sodium and high serum osmolarity, cobalamin C deficiency, Leigh disease, Galloway-Mowat syndrome, Pelizaeus-Merzbacher disease, hemolytic-uremic syndrome and Wilson disease and two cases of Alagille syndrome and methylmalonic acidemia with abnormal MRI of the basal ganglia or blood or urine analysis (abnormal group). The MR spectrum was measured by using STEAM. The MR-visible water content of the region of interest was obtained. Levels of myoinositol, choline, creatine and N-acetylaspartate were measured using a semiquantitative approach, with absolute reference calibration. In the control group, there was a gradual drop of water content over the first year of life; N-acetylaspartate, creatine and myoinositol levels showed no significant change with age, in contrast to the occipital, parietal and cerebellar regions. Choline showed a gradual decrease for the first 2 years of life and then remained fairly constant. In the abnormal group the water content was not significantly different. N-Acetylaspartate was decreased in patients with high serum sodium and high serum osmolarity, cobalamin C deficiency, Leigh disease and one case of methylmalonic acidemia. Decreased creatine was also found in Leigh disease, and decreased choline in Galloway-Mowat syndrome and Wilson disease. Myoinositol was elevated in the patient with abnormally high serum sodium, and decreased in the hemolytic-uremic syndrome.

Iron-induced apoptosis in the photoreceptor cells of rats

PURPOSE

To determine whether apoptosis is involved in retinal degeneration induced by intravitreal implantation of 5 iron particles in rat eyes.

METHODS

Autoclaved iron particles were implanted in the vitreous cavities of the experimental eyes. Glass chips were implanted in the control eyes. The experimental eyes were enucleated at various time intervals from days 1 to 15. Retinal degeneration was examined using the TdT-mediated, dUTP-biotin nick-end labeling (TUNEL) method. Electrophoresis on agarose gel was used to detect internucleosomal DNA fragmentation.

RESULTS

TUNEL-positive nuclei were observed only in the outer nuclear layer beginning on day 2. The nuclei spread throughout the outer nuclear layer by the end of day 3. No TUNEL-positive nuclei were observed in other layers throughout the experimental period. Analysis of DNA, extracted from the retinas by electrophoresis on agarose gel, revealed a typical ladder pattern of internucleosomal DNA cleavage in the experimental eyes.

CONCLUSIONS

Apoptosis occurred during photoreceptor cell death at the early phase of iron-induced retinopathy in these rats. Like photic injury, iron-induced apoptosis was limited to the outer nuclear layer.

Prognostic value of proton MR spectroscopy of cerebral hemisphere tumors in children

We studied 14 young people with newly diagnosed hemisphere tumors, aged from 3 to 20 years (average 10 years). All underwent surgery following MR imaging (MRI) and spectroscopy (MRS). The tumors studied were three glioblastomas, one each of ganglio-glioblastoma, primitive neuroectodermal tumor (PNET), rhabdoid teratoid tumor, pilocytic astrocytoma, ependymoma, anaplastic ependymoma, and gliomatosis cerebri, and four gangliogliomas. Four patients died; ten patients are alive (five with stable residual tumor, five with no evident tumor). Images and spectra were acquired on a 1.5-T imager. Proton MRS was performed before gadolinium injection in all but one case. Single-voxel techniques were utilized in all cases, using a spin-echo or STEAM sequence with a long echo time (135 or 270 ms). Peak areas of N-acetyl aspartate (NAA), choline (Cho), and creatine and phosphocreatine (Cr) were assessed. The NAA/Cho peak-area ratio was very low in the patients who died (mean +/- s.d. 0.20 +/- 0.14), and higher in the patients who are alive (0.74 +/- 0.47; P = 0.007 by two-tailed t-test). The Cr/Cho peak-area ratio also followed a similar trend for the two groups (mean +/- s.d. 0.17 +/- 0.07 and 0.49 +/- 0.30, respectively; P = 0.01 by two-tailed t-test).

Proton spectroscopy of suprasellar tumors in pediatric patients

OBJECTIVE

Magnetic resonance imaging and computed tomography provide good anatomic detail of suprasellar tumors in pediatric patients but are not able to predict histology in many cases. Proton magnetic resonance spectroscopy provides metabolic data that may add to diagnostic specificity. We preoperatively performed localized proton magnetic resonance spectroscopy on pediatric patients with suprasellar tumors and correlated the results with the histological findings. Cyst fluid obtained from patients with craniopharyngiomas was studied with high-resolution magnetic resonance spectroscopy to better understand the in vivo data.

METHODS

Nineteen patients aged 1 to 21 years underwent spectroscopy. Surgical pathological samples were obtained from 14 patients. In each of five patients, the presence of a solid chiasmatic mass in addition to clinical evidence of neurofibromatosis Type I allowed the presumptive diagnosis of chiasmatic astrocytoma. Thus, the study population included 6 patients with craniopharyngiomas, 10 with chiasmatic/hypothalamic astrocytomas, and 3 with pituitary adenomas. The data obtained were compared with those of healthy brain from age-matched participants.

RESULTS

Spectroscopy was specific for the diagnosis. All craniopharyngiomas showed a dominant peak at 1 to 2 ppm, consistent with lactate or lipids, with trace amounts of other metabolites. This was confirmed using high-resolution spectroscopy. Chiasmatic gliomas showed a profile of choline, N-acetylaspartate, and creatine, and the choline:N-acetylaspartate ratio was 2.6 +/- 1.3, compared with 0.7 +/- 0.3 for samples of healthy brain (t test, P = 0.0003). Pituitary adenomas showed only a choline peak or no metabolites at all.

CONCLUSION

Proton spectroscopy may be helpful in supplementing standard imaging for the preoperative diagnosis of three types of suprasellar tumors that are common in pediatric patients.

A role for Indian hedgehog in extraembryonic endoderm differentiation in F9 cells and the early mouse embryo

Hedgehog genes in Drosophila and vertebrates control patterning of a number of different structures during embryogenesis. They code for secreted signaling proteins that are cleaved into an active aminopeptide and a carboxypeptide. The aminopeptide can mediate local and long range events and can act as a morphogen, inducing differentiation of distinct cell types in a concentration-dependent manner. We demonstrate here that the expression of Indian hedgehog mRNA and protein is upregulated dramatically as F9 cells differentiate in response to retinoic acid, into either parietal endoderm or embryoid bodies, containing an outer visceral endoderm layer. The ES cell line D3 forms embryoid bodies in suspension culture without addition of retinoic acid and also upregulates Indian hedgehog expression. RT-PCR analysis of blastocyst outgrowth cultures demonstrates that whereas little or no Indian hedgehog message is present in blastocysts, significant levels appear upon subsequent days of culture, coincident with the emergence of parietal endoderm cells. In situ hybridization analysis for Indian hedgehog mRNA expression demonstrates the presence of elevated levels of message in the outer visceral endoderm cells relative to the core cells in mature embryoid bodies and in the visceral endoderm of Day 6.5 embryos. Whole-mount in situ hybridization analysis of Day 7.5 and 8.5 embryos indicates that Indian hedgehog expression is highest in the visceral yolk sac at this stage. F9 cell lines expressing a full length Indian hedgehog cDNA express a number of characteristics of differentiated cells, in the absence of retinoic acid. Taken together, these data suggest that Indian hedgehog is involved in mediating differentiation of extraembryonic endoderm during early mouse embryogenesis.

Prediction of posterior fossa tumor type in children by means of magnetic resonance image properties, spectroscopy, and neural networks

Recent studies have explored characteristics of brain tumors by means of magnetic resonance spectroscopy (MRS) to increase diagnostic accuracy and improve understanding of tumor biology. In this study, a computer-based neural network was developed to combine MRS data (ratios of N-acetyl-aspartate, choline, and creatine) with 10 characteristics of tumor tissue obtained from magnetic resonance (MR) studies, as well as tumor size and the patient's age and sex, in hopes of further improving diagnostic accuracy. Data were obtained in 33 children presenting with posterior fossa tumors. The cases were analyzed by a neuroradiologist, who then predicted the tumor type from among three categories (primitive neuroectodermal tumor, astrocytoma, or ependymoma/other) based only on the data obtained via MR imaging. These predictions were compared with those made by neural networks that had analyzed different combinations of the data. The neuroradiologist correctly predicted the tumor type in 73% of the cases, whereas four neural networks using different datasets as inputs were 58 to 95% correct. The neural network that used only the three spectroscopy ratios had the least predictive ability. With the addition of data including MR imaging characteristics, age, sex, and tumor size, the network's accuracy improved to 72%, consistent with the predictions of the neuroradiologist who was using the same information. Use of only the analog data (leaving out information obtained from MR imaging), resulted in 88% accuracy. A network that used all of the data was able to identify 95% of the tumors correctly. It is concluded that a neural network provided with imaging data, spectroscopic data, and a limited amount of clinical information can predict pediatric posterior fossa tumor type with remarkable accuracy.

[An epidemiologic study on the aetiological factors of primary liver cancer in Shunde City of Guangdong province]

In order to investigate the aetiological factors of Primary Liver Cancer (PLC) in Shunde City of Guangdong province, 96 clinically diagnosed PLC patients and 144 matched hospital controls were interviewed and their blood samples were examined for HBV, HCV and other seven indices. Monofactorial and multifactorial analyses were fitted by using Non-conditional Logistic Regression model. The findings confirmed the strong association between HBV infection and PLC. Histories of hepatitis and histories of eating raw fish, shrimp or salt fish were also noticed. The history of alcohol intake might have associated with PLC. The present study did not find associations between PLC and drinking water, histories of blood transfusion and injection- or exposure to insecticides. Antibody of HBV surface antigen seemed to be a protective factor with a relative risk of 0.3064 (0.1647-0.5701). The results showed that the combined effects of HBsAg infection and HCV infection were worthy for further study.

[Helicobacter pylori: a great discovery]

Within the past decade, there has been an explosion of investigative activity and publications about Helicobacter pylori pathogen. Its role in gastroduodenal diseases is becoming remarkably evident. It is accepted that H. pylori is intimately involved in the pathogenesis of chronic gastritis microbiol/DT and peptic ulcer disease. Furthermore, it is also associated with stomach cancers. The old creed in medical field that "No acid, no ulcer" would probably be changed to "No H. pylori infection, no ulcer". So, the discovery of H. pylori revolutionized our understanding of gastroduodenal diseases.