Microglia in the olfactory bulb of rats during postnatal development and olfactory nerve injury with zinc sulfate: a lectin labeling and ultrastrucutural study

Using isolectin (GSA I-B4) as a marker, this study examined the possible alterations of lectin-labeled membranous glycoproteins in microglial cells in the olfactory bulb of normal development and under experimentally induced degeneration. In light microscopy, several morphological types of microglial cells representing different degrees of cell differentiation were distributed in the bulb laminae. A gradient of microglial differentiation extending from the intermediate to superficial and intermediate to deep occurs in the bulb layers. The differentiation gradient and lectin labeling pattern of microglial cells in the developing bulb resembled those in other areas of the brain tissues. Differentiating microglia showed a gradual diminution of lectin staining when the nascent round cells transformed into the mature ramified cells. Microglia in the external plexiform layer of the olfactory bulb were the first to mature and the cells expressed very weak lectin reactivity. In mature or adult rats, some microglial cells showing intense lectin labeling were observed in the olfactory nerve layer, granule cell layer and subependymal layer. Ultrastructurally, lectin labeling was localized at the trans saccules of the Golgi apparatus. Microglial cells in other bulb laminae, however, exhibited a negative reaction for the isolectin at the Golgi apparatus. Following intranasal irrigation of zinc sulfate, some microglial cells in the olfactory nerve layer and glomerular layer were activated to become phagocytic cells with increased lectin labeling at their ramified processes. GSA I-B4 staining was also localized at their trans saccules of the Golgi apparatus. The lectin labeling pattern of these phagocytic cells resembled that of differentiating microglia in postnatal bulbs, suggesting that bulb microglia in the lesioned sites were activated through cell dedifferentiation into macrophages.

Establishment of cell lines from a tropical grouper, Epinephelus awoara (Temminck & Schlegel), and their susceptibility to grouper irido- and nodaviruses

Four tropical marine fish cell lines have been established from the eye, fin, heart and swim bladder of grouper, Epinephelus awoara (Temminck & Schlegel). Optimum media and temperature conditions for maximum growth were standardized. The eye and swim bladder cells were mostly epithelial, but the fin and heart cells were mostly fibroblastic. The viability of cells was 95% after 1 year of storage in liquid nitrogen (-196 degrees C). Besides these four cell lines, previously established grouper brain, kidney and liver cell lines were also used for a viral susceptibility study which showed that all the cell lines were sensitive to grouper iridovirus, whereas only brain, fin and liver cell lines were susceptible to the yellow grouper nervous necrosis virus (a nodavirus). Electron microscopy studies of the grouper irido- and nodaviruses in ultrathin sections of infected cells showed an abundance of viral particles in the cytoplasm of the virus-infected cells indicating the effective replication of these two viruses. It is suggested that these cell lines can be used for the isolation of putative fish specific viruses and provide a valuable tool to study the mechanisms of host-pathogen interactions. Furthermore, these cell lines upon transfection, using pEGFP-C1 and pEGFP-aMT2.5 (ayu metallothionein promoter), produced significant fluorescent signals indicating their utility for exogenous studies.

Application of a membrane bioreactor system for opto-electronic industrial wastewater treatment--a pilot study

The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention is critical to achieving more efficiency for biological degradation of pollutants. Although it is a new technology, the MBR process has been applied to industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is a high technological manufacturing industry. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds, with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N), is very difficult to meet the discharge limits. The purpose of this research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 2 m3/day capacity MBR pilot plant consisting of anoxic and aerobic tanks and a membrane bioreactor was installed for evaluation. The operation was continued for 130 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification were also successfully achieved. The effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.

Combined Fenton-MF process increases acrylonitrile removal

The Fenton oxidation process is possessed of the advantages of both oxidation and coagulation processes. In addition to these functions, Fenton's reagent is also a typical initiator of polymerization. The application of the Fenton-microfiltration process for removal of acrylonitrile (AN), which is the major raw material for manufacturing ABS reins, was investigated. As for Fenton oxidation, in the range of pH 2 to pH 4, AN removal efficiency increased as the pH increased. In experiment of the same initial molar ratio of [FeSO4]0/[H2O2]0, the higher dosage can obtain the higher removal efficiency. At pH 4, the AN removal increased as the [H2O2]0 increased for each [FeSO4]0. Acrylic acid and acrylamide were detected in the solution after Fenton oxidation. On the other hand, acrylamide, polyacrylamide, and polyacrylic acid exist in the precipitate after the Fenton oxidation of AN solution. Moreover, it was also found that the operational mode is an important factor of the combined Fenton-MF process.

Decomposition of 2-naphthalenesulfonate in aqueous solution by ozonation with UV radiation

This study investigates the ozonation of 2-naphthalenesulfonate (2-NS) combined with ultraviolet (UV) radiation. Naphthalenesulfonic acids are of importance as dye intermediates for the dye and textile auxiliary industries. Its derivatives, such as 2-NS, have been found in rivers and tannery effluents causing pollution problems. Thus, the 2-NS is of concern for the aquatic pollution control especially in the surface and waste waters. Ozonation combined with UV radiation is employed for the removal of 2-NS in the aqueous solution. Semibatch ozonation experiments were proceeded under different reaction conditions to study the effects of ozone dosage and UV radiation on the oxidation of 2-NS. The concentrations of 2-NS and sulfate are analyzed at specified time intervals to elucidate the decomposition of 2-NS. In addition, values of pH and oxidation reduction potential are continuously measured in the course of experiments. Total organic carbon is chosen as a mineralization index of the ozonation of 2-NS. The mineralization of 2-NS via the ozonation is remarkably enhanced by the UV radiation. These results can provide useful information for the proper removal of 2-NS in the aqueous solution by the ozonation with UV radiation.

Preoperative staging of cervical carcinoma with MR imaging: a reappraisal of diagnostic accuracy and pitfalls

The purpose of this study was to assess the diagnostic accuracy and pitfalls of MR imaging in preoperative staging of cervical cancer. Magnetic resonance imaging was performed to determine the tumor staging for 41 patients with cervical carcinoma emphasizing tumor size, parametrial invasion, vaginal invasion, and lymph node metastases. According to the correlation of MR findings with surgical-pathological features, there was less than 5 mm discrepancy in the size in 29 of 34 tumors (85.3%) that were larger than 1 cm. In assessing parametrial invasion, vaginal invasion and lymph node metastases, MR imaging had an accuracy of 95, 83, and 86%, respectively. In determining stage of disease and differentiating operable (< or =stage IIA) from advanced disease (> or =stage IIB), MR imaging had an accuracy of 82.9 and 93%. Pitfalls leading to staging errors included difficulties in differentiating cancer foci from surrounding tissue edema and detecting microscopic tumor extension. Magnetic resonance imaging is accurate in the evaluation of parametrial invasion and differentiation of operable from advanced disease. The ability of MR imaging to detect microscopic extra-cervical tumor extension and differentiate cancer foci from surrounding tissue edema is not as reliable.

Coronary artery calcium determined by electron beam computed tomography for predicting angiographic coronary artery disease in moderate- to high-risk Chinese patients

The aim of this study was to evaluate the prevalence of coronary calcification among moderate- to high-risk Chinese patients and to evaluate the ability of the coronary calcium score determined by electron beam computed tomography (EBCT) to predict angiographic coronary artery disease in this population. We enrolled 163 consecutive patients and analyzed their cardiovascular risk factors, coronary calcium scores and coronary angiogram results. One hundred and twenty-five patients (76.7%) had a positive EBCT scan result (coronary calcium score >0). The prevalence of calcification and the calcium scores showed a graded relation to the number of cardiovascular risk factors and age (p < 0.001 for trend). Coronary calcium scores showed statistically significant differences between patients with angiographic evidence of coronary artery disease and patients with normal coronary angiography (p < 0.05), but could not differentiate between patients with significant and insignificant coronary artery disease. Receiver operating characteristic curve analysis showed that a coronary calcium score >5 predicted angiographic coronary artery disease with 93% sensitivity and 86% specificity (area under the curve 0.95 +/- 0.019). Multivariate analysis showed a coronary calcium score >5 to be the strongest independent predictor of angiographic coronary artery disease (odds ratio 120.7, 95% confidence interval 21.7-671.4; p < 0.001). Coronary calcium score determined by EBCT appears to have a similar predictive value in Chinese patients as it does in other ethnic populations that have been reported to date.

Association of globular beta-actin with intracellular lipid droplets in rat adrenocortical cells and adipocytes

Proteins located on the surface of lipid droplets may mediate intracellular lipid metabolism. In the present study, immunofluorescent staining and polyacrylamide gel electrophoresis demonstrated that actin (43 kD) is associated with isolated intracellular lipid droplets of rat adrenocortical cells and adipocytes. Two-dimensional gel electrophoresis and immunoblot analysis further confirmed that the lipid droplet-associated actin is the beta isoform. In cultured adrenocortical cells, stress fibers and the surface of intracellular lipid droplets were labeled with anti-beta-actin monoclonal antibody, whereas FITC-phalloidin staining did not mark the rim of lipid droplets. The present results provide the first morphological evidence that globular beta-actin is associated with intracellular lipid droplets. This significant association of actin with the surface of lipid droplets suggests that beta-actin might be involved in the regulation of intracellular lipid metabolism, particularly providing insight into the important transport of lipid constituents.

Molecular basis of the adult i phenotype and the gene responsible for the expression of the human blood group I antigen

The human blood group i and I antigens are characterized as linear and branched repeats of N-acetyllactosamine, respectively. Conversion of the i to the I structure requires the activity of I-branching beta-1,6-N-acetylglucosaminyltransferase (IGnT). Thus the blood group I gene is assigned to encode a beta-1,6-N-acetylglucosaminyltransferase; however, its identity has not been confirmed. The null phenotype of I, the adult i phenotype, provides a means to identify the I gene. Interestingly, the adult i phenotype has been noted to be associated with congenital cataracts in Asians. Molecular genetic studies of 3 adult i pedigrees are reported here. The results obtained on mutation detection within the 2 I-branching enzyme encoding genes, segregation analyses, and enzyme function assays identify molecular changes associated with the adult i phenotype. The adult i phenotype in 2 of the pedigrees studied resulted from 1043G-->A and 1148G-->A mutations, which predict Gly348Glu and Arg383His alterations, respectively, in the IGnT gene. These amino acid changes abolished the original GlcNAc-transferase activity. Deletion of the IGnT gene was observed in the person with adult i phenotype in the third pedigree. These findings suggest that the IGnT gene, first reported in 1993, is the candidate for the blood group I gene. Confirmation of the blood group I gene will further assist in the investigations of the molecular genetics that control I antigen expression in secretions and the molecular basis for the association of the adult i phenotype with congenital cataracts in Asians.

Glucocorticoids manifest androgenic activity in a cell line derived from a metastatic prostate cancer

The pathophysiological mechanism(s) by which androgen independence develops in prostate cancer remains to be determined. The identification in many prostate cancer specimens of a mutant androgen receptor, T877A, with altered ligand specificity has provided an explanation for some treatment failures. The T877A mutant androgen receptor recognizes a number of nonandrogenic compounds, including certain estrogens, progestins, and even antiandrogens as androgens. However, a comprehensive screen for hormonal agents which display agonist activity on this mutant has not been performed. In this study, we characterized this clinically important receptor mutant further and found that it can be activated by a wide range of compounds, including a number of endogenous glucocorticoids. Among the most clinically relevant compounds identified are DOC and corticosterone, both of which can effectively activate the mutant receptor at concentrations normally found in blood. Dexamethasone, a synthetic glucocorticoid frequently used in various contexts for prostate cancer therapy, is also recognized as an androgen by the mutant receptor. These unexpected findings suggest the need to: (a) reassess the role of adrenally derived glucocorticoids in prostate cancer disease progression; and (b) recognize the potential for iatrogenic stimulation of disease progression with certain glucocorticoid interventions.

Residue characteristics and pore development of petrochemical industry sludge pyrolysis

Petrochemical industry bio-sludge was pyrolyzed to investigate the composition and pore size distribution of pyrolytic residue. Results indicated that the carbon, nitrogen, and hydrogen concentrations could be reduced after an increase in pyrolytic temperature. The trace element analysis indicated that Al, Ca, Fe, Mg. K, Cu, Sr, and Sb concentrated during the pyrolytic process. When forty grams of pre-dried sludge were pyrolyzed at various pyrolytic temperatures, the transfers from the gas phase to liquid phase to residue were from 21.2 to 36.0%, from 49.0 to 70.0%, and from 8.3 to 16.5%. Results of the pore size distribution examination indicated that the mesopore had the greatest effect on the bio-sludge pyrolysis. The optimal pyrolytic temperatures and times were approximately 800 degrees C for 30 min and 900 degrees C for 10 min. The conceptual model can reasonably explain the pore structure development during the pyrolysis process.

Capitalizing on the complexities of estrogen receptor pharmacology in the quest for the perfect SERM

The term Selective Estrogen Receptor Modulators (SERMs) has been used of late to describe a group of pharmaceuticals that manifest estrogen receptor (ER) agonist activity in some tissues, but that oppose estrogen action in others. Whereas the name describing this class of drugs is new, the concept is not. Indeed, compounds exhibiting tissue-selective ER agonist/antagonist properties have been around for nearly 40 years. What is new is the idea that it may be possible to capitalize on the paradoxical activities of these drugs and develop them as treatments for estrogenopathies where it is desirable to direct therapy to a specific estrogen-responsive target organ. This realization has provided the impetus for research in this area and has pushed the development and clinical use of this class of drugs. The objective of this review is to describe how the medical need for SERMs arose and how recent studies of the mechanism of action of the currently available drugs are paving the way for the development of novel drugs with improved selectivity.

Sequential MRI studies of a patient with complex partial status--a case report

Complex partial status (CPS), the status epilepticus of complex partial seizure, is rarely seen in clinical practice. The clinical presentations of CPS are characterized by confusion, slowness in response, together with stereotypic or complex automatisms and occasional secondary generalization. The electroencephalographic findings of CPS reveal characteristic focal epileptiform activities of mesial temporal region. Magnetic resonance image (MRI) is the imaging method of choice for studying epilepsy, particularly when focus is in the temporal lobe. We report a 49-year-old female with diagnosis of viral encephalitis and clinical presentation of CPS. We present the sequential brain MRI findings at acute, subacute and chronic stages of this patient.

Positron emission tomography in evaluation of dementia: Regional brain metabolism and long-term outcome

CONTEXT

Deficits in cerebral glucose utilization have been identified in patients with cognitive dysfunction attributed to various disease processes, but their prognostic and diagnostic value remains to be defined.

OBJECTIVE

To assess the sensitivity and specificity with which cerebral metabolic patterns at a single point in time forecast subsequent documentation of progressive dementia.

DESIGN, SETTING, AND PATIENTS

Positron emission tomography (PET) studies of [(18)F]fluorodeoxyglucose in 146 patients undergoing evaluation for dementia with at least 2 years' follow-up for disease progression at the University of California, Los Angeles, from 1991 to 2000, and PET studies in 138 patients undergoing evaluation for dementia at an international consortium of facilities, with histopathological diagnoses an average of 2.9 years later, conducted from 1984 to 2000.

MAIN OUTCOME MEASURES

Regional distribution of [(18)F]fluorodeoxyglucose in each patient, classified by criteria established a priori as positive or negative for presence of a progressive neurodegenerative disease in general and of Alzheimer disease (AD) specifically, compared with results of longitudinal or neuropathologic analyses.

RESULTS

Progressive dementia was detected by PET with a sensitivity of 93% (191/206) and a specificity of 76% (59/78). Among patients with neuropathologically based diagnoses, PET identified patients with AD and patients with any neurodegenerative disease with a sensitivity of 94% and specificities of 73% and 78%, respectively. The negative likelihood ratio of experiencing a progressive vs nonprogressive course over the several years following a single negative brain PET scan was 0.10 (95% confidence interval, 0.06-0.16), and the initial pattern of cerebral metabolism was significantly associated with the subsequent course of progression overall (P<.001).

CONCLUSION

In patients presenting with cognitive symptoms of dementia, regional brain metabolism was a sensitive indicator of AD and of neurodegenerative disease in general. A negative PET scan indicated that pathologic progression of cognitive impairment during the mean 3-year follow-up was unlikely to occur.

Hematometra of the rudimentary horn of a unicornuate uterus resulting from cesarean section

A 30-year-old woman complained of increasing dysmenorrhea and progressive right lower-quadrant pain after cesarean section. A pelvic mass was observed and subsequently a congenital müllerian anomaly was diagnosed upon serial examination. We report the first apparent case of hematometra of the rudimentary horn of a unicornuate uterus resulting from cesarean section.

Primary leiomyosarcoma of bone

We report a case of primary leiomyosarcoma in the right femoral diaphysis. Conventional radiographs revealed an indistinct osteolytic lesion with a very subtle periosteal reaction. MR imaging revealed an intramedullary lesion with a well-defined margin, cortical breakthrough and soft tissue extension. The lesion was isointense relative to muscle on T1-weighted imaging, iso-hypointense relative to fat on fast spin echo T2-weighted imaging, and hyperintense to muscle on fast spin echo T2-weighted imaging with fat saturation. A peripheral rim and intratumoral spoke-wheel-like enhancement in the soft tissue component of the tumor was noted on gadolinium-enhanced T1-weighted imaging with fat saturation. Such an enhancing pattern, which has not been described in the literature previously but has been seen in leiomyosarcomas elsewhere by both MR imaging and computed tomography, deserves further pathological correlation.

Polymorphism and distribution of the Secretor alpha(1,2)-fucosyltransferase gene in various Taiwanese populations

BACKGROUND

The Secretor gene (Se or FUT2), which produces alpha(1,2)-fucosyltransferase, exhibits extensive polymorphism. Six Se genes, including the weak Se (Se(w) or Se385) and three nonsecretor alleles (se571, se685, and se849) have been detected in various populations of Taiwan. The distribution of various Lewis phenotypes among the Taiwanese population groups has been shown to vary considerably.

STUDY DESIGN AND METHODS

A PCR-RFLP analysis system, which was based on the nucleotide polymorphism variation of the different Se alleles and which can reveal the Se genotype of an individual easily and accurately, was developed. The distribution of the Se alleles among Taiwanese population groups, including the two major populations, Minnan and Hakka Taiwanese, and 11 indigenous groups, was analyzed by the method.

RESULTS

Frequencies of the Se alleles among the Taiwanese populations were revealed. The distribution of the nonsecretor alleles, especially se849, showed a marked variation. A good correlation was observed between a person's Se genotype and Lewis phenotype.

CONCLUSION

The Se genes have a polymorphic distribution among various Taiwanese populations, and this agrees with previous results for Lewis phenotype distributions. The Se(w) allele and the three se alleles are responsible for the Le(a+b+) and Le(a+b-) phenotypes, respectively.

Adsorption of acid dye onto activated carbons prepared from agricultural waste bagasse by ZnCl2 activation

A series of activated carbons were prepared from agricultural waste sugarcane bagasse by chemical activation with zinc chloride (ZnCl2) as an activating agent at 500 degrees C and 0.5 h soaking time. The Langmuir surface area and total pore volume were used to estimate the average pore diameter of the carbon products. The values of the surface area and pore volume increased linearly with increase in the impregnation ratio (IR) up to 100 wt%. The adsorption capacities of the derived adsorbents for Acid Orange 10 were measured at 20 degrees C and 40 degrees C to gain further insights into the acidic surface oxides of the adsorbent from the results of Fourier transform infrared (FTIR) spectroscopy analysis and pH measurement. Adsorption isotherms of the acid dye on adsorbents prepared were determined and correlated with common isotherm equations. It was found that the Langmuir model appears to fit the isotherm data better than the Freundlich model. The physical properties of these adsorbents were consistent with the parameters obtained from the isotherm equations.

Variant palmaris profundus enclosed byan unusual loop of the median nerve

According to the usual description in most anatomy texts, the median nerve in the forearm passes between the 2 heads of pronator teres. It continues distally between flexor digitorum superficialis and profundus almost to the retinaculum. Muscular branches leave the nerve near the elbow and supply all superficial muscles of the anterior part of the forearm except flexor carpi ulnaris. Many variations of the median nerve in the forearm have been reported (Urban & Krosman, 1992). The palmaris profundus is also a rare anomaly of the forearm (Dyreby & Engber, 1982). It originates from the radial side of the common flexor tendon in the proximal forearm and inserts into the undersurface of the palmar aponeurosis. The origin of palmaris profundus may be close to the median nerve and its branches, and may be involved in compressive neuropathy of the anterior interosseous nerve. Its tendon crossing through the carpal canal has been implicated in the carpal tunnel syndrome (reviewed by Lahey & Aulicino, 1986). In some cases, palmaris profundus was found enclosed in a common fascial sheath with the median nerve (Stark, 1992; Sahinoglu et al. 1994). To indicate its close association with the median nerve, the palmaris profundus was also named ‘musculus comitans nervi mediani’ (Sahinoglu et al. 1994). This article reports an unusual loop of the median nerve encircling an anomalous palmaris profundus in the forearm, which, to the best of our knowledge, has not been previously described.

Utilization of agricultural waste corn cob for the preparation of carbon adsorbent

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K2CO3) and carbon dioxide (CO2). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO2 was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption-desorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO2 is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m2/g and about 1.0 cm3/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K2CO3 and CO2 was suitable for the preparation of large-surface-area activated carbons.

The triple-phase CT image appearance of post-irradiated livers

OBJECTIVE

To evaluate the sequential CT appearance of the liver after hepatic irradiation and to investigate the correlation between CT findings and radiation-induced hepatic injury.

MATERIAL AND METHODS

The triple-phase CT images of 18 patients with hepatocellular carcinomas (HCC) after hepatic irradiation were retrospectively reviewed (in total 41 CT studies). The high-dose region within the liver was defined as the area receiving more than 90% of the prescribed irradiation dose. The mean radiation dose was 55.5 Gy. Density changes and patterns of enhancement in the high-dose region were classified as three types: type I, constant low-density change in all phases; type II, low-density change in both pre-contrast and arterial phases, and iso-density change in the portal phase; type III, low- or iso-density change in the pre-contrast phase, low- or high-density change in the arterial phase, and persistent high-density change in the portal phase. The interval between completion of radiotherapy and the CT examinations ranged from 9 to 469 days, with a mean of 147 days.

RESULTS

Nine of the 41 CT studies presented with type I, 9 with type II, and 16 with type III CT findings. The mean interval between completion of radiotherapy and the appearance of types I, II, and III CT findings were 74, 183, and 220 days, respectively. The interval was significantly shorter for type I findings than for type II and type III. The difference in interval was not significant between type II and type III. A type I finding with constant low-density change in the high-dose region of the liver was the most common pattern of CT findings within the first 3 months after hepatic irradiation. Either types II or III findings were frequently seen after 3 months.

CONCLUSION

The sequential CT appearance and the density changes may indicate correlation with the pathogenesis of veno-occlusive disease.

A comparative MR and pathological study on fetal CNS disorders

OBJECT

We used MR after sonography to help us in prenatal counseling in 58 complicated pregnancies from 1998 to 2000.

METHODS

All fetal MR examinations were undertaken with a 1.5-T magnet using a body-phased-array coil and an ultrafast imaging technique, half-Fourier single-shot turbo spin-echo (HASTE). Twelve fetuses were found to have major anomalies, and in each of these cases either delivery was induced or the pregnancy was terminated. In 6 of the fetuses, with anomalies of the central nervous system, postmortem examinations were then performed after they failed to survive, and these constitute the patient sample investigated in the current study. The fetal gestational ages in these 6 cases ranged from 24 to 32 weeks. MR imaging demonstrated morphological details of the anomalies. They were: alobar holoprosencephaly in 2, middle interhemispheric fusion in 1, alobar holoprosencephaly with Dandy-Walker malformations in 1, a Dandy-Walker variant in 1 and twin-twin transfusion syndrome with hypoxic-ischemic injury to the brain in 1.

CONCLUSIONS

Postmortem examinations confirmed the MR diagnoses, and these observations support us in improving our understanding of the pathogenesis of fetal CNS anomalies.

The organic precursors affecting the formation of disinfection by-products with chlorine dioxide

The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics.