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.

Sonographic appearance of lipoma of the inferior vena cava

Lipomas of the major central veins are rare, and their sonographic features have rarely been reported. We report a case in which a lipoma of the inferior vena cava (IVC) was incidentally identified during liver sonography in a 68-year-old man. Sonography of the upper abdomen revealed coarsening of the liver echotexture, with a relatively small liver and atrophy of the right hepatic lobe. A 2-cm hypoechoic hepatic nodule was visualized in segment IV. Sonography also showed a 2.2- x 1.8-cm, highly echogenic, homogeneous nodule in the hepatic segment of the IVC at its junction with the right atrium. The lumen of the IVC was partially occluded. The CT and MRI appearances of the IVC lesion were consistent with a lipoma, which was not treated because there was no clinical evidence of obstruction. Histopathologic analysis following a sonographically guided biopsy of the liver nodule revealed hepatocellular carcinoma, which was treated by percutaneous ethanol injection.

Response of amoeboid and differentiating ramified microglia to glucocorticoids in postnatal rats: a lectin histochemical and ultrastructural study

After glucocorticoid injection(s), the number of amoeboid microglial cells (AMC) in the corpus callosum labelled by lectin was markedly reduced when compared with the corresponding control rats. In rats killed at the age of 7 days, all the labeled cells differentiated to become ramified microglia. Ultrastructurally, the AMC in glucocorticoid-injected rats were extremely vacuolated and showed increased lipid droplets. Furthermore, the cells displayed varied lectin labelling patterns especially at both the trans saccules of the Golgi apparatus and lysosomes. In differentiating ramified microglia, massive cellular debris and lectin-stained vesicles or vacuoles were observed; some of the latter appeared to fuse with the plasma membrane. The most striking feature after glucocorticoid (GCC) treatment was the complete diminution of lectin labelling at the Golgi saccules in some differentiating ramified microglia. The present results have demonstrated different effects of glucocorticoids on AMC and differentiating ramified microglia. The differential response of AMC and differentiating ramified microglia to the immunosuppressive drugs may be attributed to the fact that these cells in the postnatal brains subserve different functions or that they are at different differentiation stages. In other words, the sensitivity of microglial cells to the immunosuppressive drugs is dependent upon the stage of cell maturation/differentiation.

Sonographic features of xanthogranulomatous pyelonephritis

PURPOSE

The purpose of this study was to describe the various sonographic features of xanthogranulomatous pyelonephritis (XGP).

METHODS

We retrospectively reviewed the CT, sonographic, and medical records of patients diagnosed with XGP from January 1981 to December 1998. Twenty-seven patients for whom XGP was histopathologically confirmed were included in the study. There were 12 men and 15 women, with an age range of 21-86 years (mean, 57 years). All patients had undergone sonography of the kidneys. The renal size, shape, and outline were recorded. The presence of perinephric fluid accumulation, of obstructive uropathy, or of internal echoes in the dilated collecting system and the echotexture of the renal parenchyma were documented.

RESULTS

We categorized the XGP into 4 groups on the basis of the sonographic features: (1) diffuse hydronephrotic, 12 patients (44%); (2) diffuse parenchymal, 9 patients (33%); (3) diffuse contracted, 4 patients (15%); and (4) segmental or focal, 2 patients (7%). A localized perinephric fluid collection was present in 4 patients (15%). The preoperative sonographic diagnoses were pyonephrosis (n = 14, 52%), renal pelvic tumor with possible associated infection (n = 5, 19%), renal parenchymal mass (n = 2, 7%), hydronephrosis (n = 2, 7%), and chronic pyelonephritis with renal atrophy (n = 4, 15%). XGP was considered a possible diagnosis in only 11 patients (41%).

CONCLUSIONS

XGP has no specific sonographic features but is suggested by parenchymal thinning and hydronephrosis, sonographic signs of chronic obstructive uropathy caused by stones; echoes in the dilated collecting system; and a perinephric fluid collection. CT, needle biopsy, or both are recommended to further evaluate and confirm sonographically suspected XGP.

The role of high-resolution ultrasonography in management of calcific tendonitis of the rotator cuff

This article predicts the possibility of resorption of the calcific plaques in the shoulder using high-resolution ultrasonography (HRUS) and color Doppler ultrasound (CDUS), and evaluates the therapeutic effect of US-guided fine-needle multiple punctures of the calcific plaque. A total of 100 patients with calcific tendenosis were divided into 3 groups: In group 1, patients having chronic shoulder pain received conservative treatment; in group 2, patients having acute exacerbation of shoulder pain also received conservative treatment; and group 3 patients received US-guided fine-needle multiple punctures or aspiration. In CDUS, all images were classified as grade 0 (no color flow signals), grade 1 (weak spotty color flow signal), grade 2 (few rod-like color flow signals), grade 3 (many rod-like or linear color flow signals). In the follow-up study, marked improvement of patients' clinical condition with more than 50% size reduction of calcific plaque was defined as an effective treatment. There was no significant difference between group 1 and group 3 (p = 0.558) in CDUS, but there was a significant difference between group 1 and group 2 (p = 0.000), and group 2 and group 3 (p = 0.000) on the basis of classification of grade < 1 and grade > or = 1. There was also significant difference in the follow-up result of effective management between group 1 and group 3 (p = 0.000), and group 1 and group 2 (p = 0.000). In conclusion, HRUS with CDUS proved to be a good modality in evaluating the possibility of resorption of shoulder calcification and, if CDUS > or = grade 1 in calcific tendonitis, we highly recommend conservative treatment with regular follow-up. On the other hand, if CDUS < grade 1, fine-needle repeated puncture could be considered as an effective alternative treatment.

Lithopedion

Lithopedion is a rare obstetrical outcome of an undiagnosed and untreated advanced abdominal pregnancy, mostly found incidentally. We present a case of lithopedion. In a 76 year-old female suffering from cervical neoplasm, total abdominal hysterectomy was performed for the lesion and the lithopedion was found incidentally. The patient's history was unremarkable, and laboratory tests were normal. The patient recalled having experienced a severe abdominal pain about 50 years before. Her physician had felt "a benign tumor" in her pelvis at that time, indicating that the stone child had retained in the maternal peritoneal cavity for 50 years.

Preparation of activated carbons from corn cob catalyzed by potassium salts and subsequent gasification with CO2

In the present study, granular activated carbons were prepared from agricultural waste corn cob by chemical activation with potassium salts and/or physical activation with CO2. Under the experimental conditions investigated, potassium hydroxide (KOH) and potassium carbonate (K2CO3) were effective activating agents for chemical activation during a ramping period of 10 degrees C/min and subsequent gasification (i.e., physical activation) at a soaking period of 800 degrees C. Large BET surface areas (>1,600 m2/g) of activated carbons were thus obtained by the combined activation. In addition, this study clearly showed that the porosity created in the acid-unwashed carbon products is substantially lower than that of acid-washed carbon products due to potassium salts left in the pore structure.

Sensitivity of diffusion-weighted magnetic resonance imaging in the diagnosis of acute lacunar infarcts

BACKGROUND AND PURPOSE

Heightened interest in the early diagnosis and treatment of acute stroke challenges neuroimaging specialists to optimize available modalities and to develop new techniques for the evaluation of cerebrovascular disease. The purpose of this study was to evaluate the sensitivity of diffusion-weighted (DW) magnetic resonance (MR) imaging in detecting early small infarcts and in differentiating acute from nonacute small infarcts when conventional MR imaging demonstrates multiple small infarcts.

METHODS

Thirty-eight consecutive patients with a clinical diagnosis of lacunar infarcts (20 men and 18 women, aged 50-79 yr) who underwent DW MR imaging within 3 days of symptom onset were enrolled in this study. All patients underwent both conventional fast spin-echo (FSE) MR imaging and DW MR imaging. Apparent diffusion coefficient (ADC) maps were also acquired. All patients had at least one of the following classic lacunar syndromes: pure motor hemiparesis, ataxic hemiparesis, dysarthria-clumsy hand, pure sensory stroke, and sensorimotor stroke.

RESULTS

Thirty-six patients (40 acute lesions) had focal areas of high intensity on DW MR imaging associated with their clinical symptoms. Acute lacunar infarcts were seen on DW MR imaging as bright areas of decreased ADC ratio (range 0.31-0.85, mean 0.64). Lesion conspicuity with DW MR imaging was superior to that with FSE in 33 acute lesions. In four patients with small hyperacute (within 6 hours) infarcts, DW MR imaging was particularly sensitive for infarcts that were not visible on FSE sequences. The sensitivity of DW MR imaging and ADC map for acute lacunar infarcts was 95%, specificity 94%, positive predictive value 97%, negative predictive value 90%, and accuracy 95%. In 15 patients with both acute and nonacute old small infarcts, DW MR imaging and ADC map could easily distinguish the new infarct from adjacent old ones, although this distinction was difficult to make with FSE.

CONCLUSIONS

DW MR imaging accompanied by ADC map is a sensitive diagnostic modality for hyperacute and acute lacunar infarcts. It is also sensitive in distinguishing fresh small infarcts from adjacent multiple old infarcts.

Magnetic resonance imaging appearance of intradural spinal lipoma

Intradural spinal lipoma not associated with spinal dysraphism is a rare tumor often presenting with nonspecific symptoms and indolent clinical course. Its intradural location and fat component is the key for proper preoperative diagnosis, which could hardly be made by traditional imaging studies including plain film and myelography. Both CT and MRI can reveal the fat component of the tumor, but MRI is superior to CT in demonstrating its relationship with adjacent normal nerve tissue. We report a 32-year-old man who had back pain for years and the symptom progressed rapidly in recent two months. MRI revealed an intradural tumor at T12 level with high signal intensity on both T1- and T2-weighted images. The signal intensity dropped dramatically with fat saturation technique, which confirmed fat as its main component. The patient received surgery and the tumor was proved to be an intraspinal lipoma.

Differential coronary artery calcification detected by electron beam computed tomography as an indicator of coronary stenosis among patients with stable angina pectoris

BACKGROUND

The detection of coronary artery calcification by electron beam computed tomography (EBCT) has been suggested as an indicator of atherosclerosis and coronary artery disease (CAD). There is no consensus on the correlation between coronary calcification and angiographically significant stenosis on an artery-by-artery basis.

OBJECTIVE

To examine the relationship between coronary calcification score (CCS) and the presence of significant CAD on an artery-by-artery basis in patients with stable angina pectoris.

METHODS AND RESULTS

EBCT and coronary angiogram (CAG) were evaluated in 71 patients with stable angina and in nine control subjects. The CCSs of each of the four major coronary arteries were highest in patients with significant CAD (n=43), followed by patients with insignificant CAD (n=5), patients with syndrome X (n=23) and control subjects, respectively. Calcification scores of the four major coronary arteries appeared to have different predictive power for significant stenosis on the same vessel. For left main (LM) and left anterior descending (LAD) coronary arteries, CCSs of vessels with significant stenoses were not different from those without significant stenoses (values expressed as medians: LM 0 versus 1; LAD 98.5 versus 70; not significant). Calcification scores of left circumflex (LCX) and right coronary arteries (RCA) were significantly higher in vessels with significant stenosis (LCX 49.5 versus 0; RCA 53 versus 1; P<0.05). CCSs appeared to be moderately useful to predict significant stenoses in these two vessels (areas under receiver operating characteristic curves: LCX 0.68+/-0.08, 95% CI 0.52 to 0.81; RCA 0.71+/-0.08, 95% CI 0.55 to 0.84).

CONCLUSIONS

The CCSs of RCA and LCX arteries, but not those of LM and LAD arteries, may predict significant angiographic stenosis on an artery-by-artery basis among patients with stable angina pectoris.

Primary structure and developmental expression of zebrafish sodium channel Na(v)1.6 during neurogenesis

A zebrafish sodium channel cDNA encoding a 1949-amino acid polypeptide, Na(v)1.6, was isolated. Two transcripts were detected in zebrafish adult brain but not in cardiac or skeletal muscle. The RNase protection analysis confirmed the neural specificity of zebrafish Na(v)1.6 24 hours postfertilization (hpf) Na(v)1.6 was expressed in the trigeminal ganglion, anterior and posterior lateral line ganglia, rhombomeres, and Rohon-Beard neurons. This preferential localization suggests that Na(v)1.6 plays an important role in tactile sensitivity. The abundance of zebrafish Na(v) 1.6 mRNA in the central and peripheral nervous systems increased markedly between 48 and 72 hpf, during the maturation of the nervous system.

Characterization of activated carbons prepared from sugarcane bagasse by ZnCl2 activation

Activated carbons were prepared from the agricultural waste of sugarcane bagasse by the chemical activation with zinc chloride (ZnCl2) at the activation temperature of 500 degrees C with soaking time of 0.5 hour. The influence of activation parameters on the final carbon products was examined by varying the impregnation ratio (i.e., mass ratio of added ZnCl2 to bagasse) and bagasse size. The physical properties of carbon products were characterized by nitrogen adsorption/desorption isotherms (at 77 K) and helium displacement method. The surface area and pore volume of carbons were thus obtained by the BET equation and t-plot method. Also, the particle density and porosity of carbons were estimated by the total pore volume and true density. The increases of the values of surface area and pore volume are approximately proportional to the impregnation ratio. The microporous carbon product with the BET surface area of 905 m2/g and total pore volume of 0.44 cm3/g was obtained in the present study. Further, the adsorption isotherms of two acid dyes from aqueous solutions onto the carbon products were performed at 30 degrees C. The results show that the adsorption isotherms of acid dyes with high molecular weight or large molecular size on the microporous adsorbents of activated carbons are plateau forms, indicating multilayer adsorptions, which may be attributed to the steric hindrance of the adsorbate molecules.

Phosphorylation of Ser363, Thr370, and Ser375 residues within the carboxyl tail differentially regulates mu-opioid receptor internalization

Prolonged activation of opioid receptors leads to their phosphorylation, desensitization, internalization, and down-regulation. To elucidate the relationship between mu-opioid receptor (MOR) phosphorylation and the regulation of receptor activity, a series of receptor mutants was constructed in which the 12 Ser/Thr residues of the COOH-terminal portion of the receptor were substituted to Ala, either individually or in combination. All these mutant constructs were stably expressed in human embryonic kidney 293 cells and exhibited similar expression levels and ligand binding properties. Among those 12 Ser/Thr residues, Ser(363), Thr(370), and Ser(375) have been identified as phosphorylation sites. In the absence of the agonist, a basal phosphorylation of Ser(363) and Thr(370) was observed, whereas [d-Ala(2),Me-Phe(4),Gly(5)-ol]enkephalin (DAMGO)-induced receptor phosphorylation occurs at Thr(370) and Ser(375) residues. Furthermore, the role of these phosphorylation sites in regulating the internalization of MOR was investigated. The mutation of Ser(375) to Ala reduced the rate and extent of receptor internalization, whereas mutation of Ser(363) and Thr(370) to Ala accelerated MOR internalization kinetics. The present data show that the basal phosphorylation of MOR could play a role in modulating agonist-induced receptor internalization kinetics. Furthermore, even though mu-receptors and delta-opioid receptors have the same motif encompassing agonist-induced phosphorylation sites, the different agonist-induced internalization properties controlled by these sites suggest differential cellular regulation of these two receptor subtypes.