Relating microstructure to rheology of a bundled and cross-linked F-actin network in vitro

The organization of individual actin filaments into higher-order structures is controlled by actin-binding proteins (ABPs). Although the biological significance of the ABPs is well documented, little is known about how bundling and cross-linking quantitatively affect the microstructure and mechanical properties of actin networks. Here we quantify the effect of the ABP scruin on actin networks by using imaging techniques, cosedimentation assays, multiparticle tracking, and bulk rheology. We show how the structure of the actin network is modified as the scruin concentration is varied, and we correlate these structural changes to variations in the resultant network elasticity.

Elastic behavior of cross-linked and bundled actin networks

Networks of cross-linked and bundled actin filaments are ubiquitous in the cellular cytoskeleton, but their elasticity remains poorly understood. We show that these networks exhibit exceptional elastic behavior that reflects the mechanical properties of individual filaments. There are two distinct regimes of elasticity, one reflecting bending of single filaments and a second reflecting stretching of entropic fluctuations of filament length. The mechanical stiffness can vary by several decades with small changes in cross-link concentration, and can increase markedly upon application of external stress. We parameterize the full range of behavior in a state diagram and elucidate its origin with a robust model.

Colloid surface chemistry critically affects multiple particle tracking measurements of biomaterials

Characterization of the properties of complex biomaterials using microrheological techniques has the promise of providing fundamental insights into their biomechanical functions; however, precise interpretations of such measurements are hindered by inadequate characterization of the interactions between tracers and the networks they probe. We here show that colloid surface chemistry can profoundly affect multiple particle tracking measurements of networks of fibrin, entangled F-actin solutions, and networks of cross-linked F-actin. We present a simple protocol to render the surface of colloidal probe particles protein-resistant by grafting short amine-terminated methoxy-poly(ethylene glycol) to the surface of carboxylated microspheres. We demonstrate that these poly(ethylene glycol)-coated tracers adsorb significantly less protein than particles coated with bovine serum albumin or unmodified probe particles. We establish that varying particle surface chemistry selectively tunes the sensitivity of the particles to different physical properties of their microenvironments. Specifically, particles that are weakly bound to a heterogeneous network are sensitive to changes in network stiffness, whereas protein-resistant tracers measure changes in the viscosity of the fluid and in the network microstructure. We demonstrate experimentally that two-particle microrheology analysis significantly reduces differences arising from tracer surface chemistry, indicating that modifications of network properties near the particle do not introduce large-scale heterogeneities. Our results establish that controlling colloid-protein interactions is crucial to the successful application of multiple particle tracking techniques to reconstituted protein networks, cytoplasm, and cells.

A fatal case of Vibrio vulnificus meningoencephalitis

The objective of this paper is to report a rare case of Vibrio vulnificus presenting as meningoencephalitis without a wound infection. Vibrio vulnificus is capable of causing severe and often fatal infections in susceptible individuals. It commonly causes necrotizing wound infections, primary septicemia, and gastroenteritis. A 69-year-old man had meningoencephalitis with lesion on the red nucleus, substantia nigra, basal ganglia, and dentate nucleus as the initial clinical manifestation of a V. vulnificus infection. This is the first case of V. vulnificus infection in which MRI demonstrated the involvement of deep nuclei of the brain.

Clostridium perfringens septicemia with thrombophlebitis of the portal vein

We report a case of patient with Clostridium perfringens septicemia and thrombophlebitis of the portal vein (pylephlebitis), probably secondary to an initially unrecognized gastric ulcer. The extension of the thrombosis from the superior mesenteric vein to the main portal vein on a repeat CT scan and subsequent partial resolution of the thrombus with antibiotic therapy alone, suggested that Clostridium perfringens bacteremia may have enhanced the formation of thrombus. The coexistence of Clostridium perfringens septicemia and pylephlebitis should prompt a search for intra-abdominal processes as the portal of entry of infection.

Renal perfusion abnormality. Coded harmonic angio US with contrast agent

PURPOSE

Coded harmonic angio (CHA) US is a recently developed technique that can depict the effects of contrast agents. The purpose of this study was to determine the role of this technique in depicting the enhancement patterns of various renal perfusion abnormalities compared with dynamic CT.

MATERIAL AND METHODS

During a 6-month period, various renal lesions including renal cell carcinoma (n=12), transitional cell carcinoma (n=5), acute pyelonephritis (n=5), and renal trauma (n=2) were evaluated with CHA US using a microbubble contrast agent. US images were obtained before contrast administration and with a bolus injection of 4 g of microbubble contrast agent (300 mg/ml) every 10 s for 1 min and every minute for 5 min. The contrast enhancement patterns of various renal masses were compared with dynamic CT.

RESULTS

Of 12 renal cell carcinomas, 9 (75%) showed heterogeneous enhancement and the remaining 3 (25%) showed homogeneous enhancement. Enhancement of more than adjacent renal parenchyma was seen 16-252 s after injection. The duration of enhancement was 13-208 s (mean, 80 s). All transitional cell carcinomas showed peripheral enhancement. Enhancement was seen 22-270 s after injection. The duration of enhancement was 191-238 s (mean, 291 s). Five patients with acute pyelonephritis and 2 with renal trauma showed focal perfusion defects not shown on the pre-contrast examinations.

CONCLUSION

CHA US with microbubble contrast agent is an effective US technique for the evaluation of both tumor vascularity and renal perfusion abnormality.

Renal perfusion abnormality. Coded harmonic angio US with contrast agent

PURPOSE

Coded harmonic angio (CHA) US is a recently developed technique that can depict the effects of contrast agents. The purpose of this study was to determine the role of this technique in depicting the enhancement patterns of various renal perfusion abnormalities compared with dynamic CT.

MATERIAL AND METHODS

During a 6-month period, various renal lesions including renal cell carcinoma (n=12), transitional cell carcinoma (n=5), acute pyelonephritis (n=5), and renal trauma (n=2) were evaluated with CHA US using a microbubble contrast agent. US images were obtained before contrast administration and with a bolus injection of 4 g of microbubble contrast agent (300 mg/ml) every 10 s for 1 min and every minute for 5 min. The contrast enhancement patterns of various renal masses were compared with dynamic CT.

RESULTS

Of 12 renal cell carcinomas, 9 (75%) showed heterogeneous enhancement and the remaining 3 (25%) showed homogeneous enhancement. Enhancement of more than adjacent renal parenchyma was seen 16-252 s after injection. The duration of enhancement was 13-208 s (mean, 80 s). All transitional cell carcinomas showed peripheral enhancement. Enhancement was seen 22-270 s after injection. The duration of enhancement was 191-238 s (mean, 291 s). Five patients with acute pyelonephritis and 2 with renal trauma showed focal perfusion defects not shown on the pre-contrast examinations.

CONCLUSION

CHA US with microbubble contrast agent is an effective US technique for the evaluation of both tumor vascularity and renal perfusion abnormality.

Association of the CD14 gene -159C polymorphism with progression of IgA nephropathy

The risk factors associated with the progression of IgA nephropathy (IgAN), the most common form of glomerulonephritis, are unclear. It has been suggested that CD14 signalling in response to various microbes affects the natural history of chronic inflammatory conditions. It has been hypothesised that variants in the promoter region of the CD14 gene might alter the expression of CD14, and this in turn could influence the progressive nature of IgAN. PCR-RFLP was used to determine the polymorphism at the -159 site (T to C). The distribution of the CD14/-159 polymorphism was no different in patients with IgAN (n=216) compared to 171 healthy controls. After follow up for 86 months, it was found that an excess of the C genotype occurred in patients with progressive disease (p=0.03) and the risk of disease progression increased as the number of C alleles increased (p for trend = 0.002). The hazard ratio for progression in the patients with the CC genotype was 3.2 (p=0.025) compared with the patients possessing the TT genotype. After LPS stimulation, sCD14 was released more abundantly from the PBMCs of the TT subjects than from that of the CC subjects (p=0.006), even though mCD14 expression level was no different. In addition, the TT subjects released less IL-6 than the CC subjects after stimulation (p=0.0003). These results suggest that the CD14/-159 polymorphism is an important marker for the progression of IgAN and may modulate the level of the inflammatory responses.

Effect of cooking on the formation of N-nitrosodimethylamine in Korean dried seafood products

Only N-nitrosodimethylamine (NDMA) was detected when N-nitrosamines (NA) were analysed in seven dried seafood products, either uncooked or cooked. The cooking methods used were a briquet fire, a gas range, an electric oven, a microwave oven, a steam cooker and an electric coil cooker. The contents of NDMA ranged from 1.0 to 46.9 microgram kg(-1) in uncooked products. When these samples were cooked, regardless of the cooking method, the content of NDMA tended to increase, ranging from 1.1 to 630.5 microgram kg(-1). In general, indirect heating such as a steam cooker and a microwave oven, as compared with direct heating such as a gas range and a briquet fire, caused less increase in NDMA during cooking.

Identification of amino acid residues lining the pore of a gap junction channel

Gap junctions represent a ubiquitous and integral part of multicellular organisms, providing the only conduit for direct exchange of nutrients, messengers and ions between neighboring cells. However, at the molecular level we have limited knowledge of their endogenous permeants and selectivity features. By probing the accessibility of systematically substituted cysteine residues to thiol blockers (a technique called SCAM), we have identified the pore-lining residues of a gap junction channel composed of Cx32. Analysis of 45 sites in perfused Xenopus oocyte pairs defined M3 as the major pore-lining helix, with M2 (open state) or M1 (closed state) also contributing to the wider cytoplasmic opening of the channel. Additional mapping of a close association between M3 and M4 allowed the helices of the low resolution map (Unger et al., 1999. Science. 283:1176-1180) to be tentatively assigned to the connexin transmembrane domains. Contrary to previous conceptions of the gap junction channel, the residues lining the pore are largely hydrophobic. This indicates that the selective permeabilities of this unique channel class may result from novel mechanisms, including complex van der Waals interactions of permeants with the pore wall, rather than mechanisms involving fixed charges or chelation chemistry as reported for other ion channels.

Interdependent effect of angiotensin-converting enzyme and platelet-activating factor acetylhydrolase gene polymorphisms on the progression of immunoglobulin A nephropathy

In order to investigate the interdependent action of the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene and polymorphism in exon 11 (C1136-->T; Ala379Val) of the platelet-activating factor acetylhydrolase (PAF-AH) gene, which encodes a functional antagonist of PAF, on the progression of immunoglobulin A (IgA) nephropathy, we analysed both polymorphisms in patients with primary IgA nephropathy, who were followed-up for longer than 3 years. During the follow-up (87.3 +/- 50.0 months), the disease progressed in 38 of the 191 patients (19.9%). The D allele of the ACE gene in the absence of the T allele of the PAF-AH gene did not affect the prognosis [odds ratio (OR), 3.6; 95% confidence interval (CI), 0.8-16.4] and neither did the T allele in the absence of the D allele (OR, 3.0; 95% CI, 0.4-24.2). However, the presence of both was a significant prognostic factor (OR, 6.6; 95% CI, 1.4-31.3). After adjusting for other risk factors, the presence of both proved to be an independent risk factor (OR, 4.5; 95% CI, 1.6-12.7). These results suggest that the interdependent effects of ACE and PAF-AH polymorphisms on the progression of IgA nephropathy might be more important than the effect of the individual polymorphisms.

A case of giant congenital nevocytic nevus with neurotization and onset of vitiligo

The authors report the case of a 21-year-old woman with a giant congenital nevocytic nevus (GCNN) who developed vitiligo at the age of 16 years on skin areas remote from the GCNN. This is the first reported case of GCNN developing neurotization combined with vitiliginous changes within the GCNN lesion. Treatment with PUVA achieved repigmentation of the vitiligo lesions, except for the hypochromic areas within the area of the nevus that were shielded from UVA radiation.

Acute abdominal pain in systemic lupus erythematosus: focus on lupus enteritis (gastrointestinal vasculitis)

OBJECTIVE

To determine the causes of acute abdominal pain in systemic lupus erythematosus (SLE) and to compare the clinical and laboratory data, especially antiphospholipid antibodies and the SLE Disease Activity Index (SLEDAI), between lupus enteritis (gastrointestinal vasculitis) and acute abdominal pain without lupus enteritis in patients with SLE.

METHODS

A retrospective study was carried out for all patients admitted with SLE from 1993 to March 2001. The SLEDAI and laboratory data were collected at the time of diagnosis of SLE and at the time of acute abdominal pain. Lupus enteritis (gastrointestinal vasculitis) was diagnosed by clinical investigation and abdominal computed tomographic findings.

RESULTS

Chart review identified 175 patients (20 male, 155 female) who had been admitted with SLE. Of these patients, 38 (22%) presented with acute abdominal pain. Lupus enteritis was the most common cause of acute abdominal pain. Patients were divided into three groups: group 1: lupus enteritis (n=17), group 2: acute abdominal pain without lupus enteritis (n=21), and group 3: SLE without acute abdominal pain (n=137). There was no difference in age and sex among the three groups. Antiphospholipid, anti-RNP, anti-Sm, anti-Ro, and anti-La antibodies did not differ among the three groups. There was no difference in the SLEDAI at the time of diagnosis and at the time of acute abdominal pain between groups 1 and 2. Complement, erythrocyte sedimentation rate, C reactive protein, and anti-dsDNA measured at the time of acute abdominal pain did not differ between groups 1 and 2. A drop in the white blood cell count at the time of abdominal pain was more prominent in group 1 than group 2. In lupus enteritis, the jejunum and ileum were the sites most commonly affected. Rectal involvement was rare. Even though four patients relapsed, all the patients with lupus enteritis, including those who relapsed, responded well to corticosteroid.

CONCLUSION

Lupus enteritis is the most common cause of acute abdominal pain in SLE. All patients with lupus enteritis responded well to a high dose of a corticosteroid without surgical intervention. The SLEDAI and laboratory data, except leucopenia, do not correlate with the occurrence of lupus enteritis.

Solitary fibrous tumor in the buccal space: MR findings with pathologic correlation

We report MR findings in a case of a solitary fibrous tumor involving the buccal space in a middle-aged man. On MR images, most of the mass was isointense and hyperintense to the muscle on T1- and T2-weighted images, respectively, and showed homogeneously strong enhancement on contrast-enhanced T1-weighted images. The medial peripheral portion, which was isointense on T2-weighted images and showed less enhancement on contrast-enhanced T1-weighted images, corresponded to the hypocellular and collagenous sclerotic area on pathologic correlation.

Synthesis and structural characterization of PHP[(C(5)Me(4))(2)], a monodentate chiral phosphine derived from intramolecular C-C coupling of tetramethylcyclopentadienyl groups: an evaluation of steric and electronic properties

The chiral monodentate phosphine PhP[(C(5)Me(4))(2)] is readily obtained by oxidation of the lithium complex Li(2)[PhP(C(5)Me(4))(2)] with I(2), which couples the two cyclopentadienyl groups to form a five-membered heterocyclic ring. The steric and electronic properties of PhP[(C(5)Me(4))(2)] have been evaluated by X-ray diffraction and IR spectroscopic studies on a variety of derivatives, including Ph[(C(5)Me(4))(2)]PE (E = S, Se), Cp*MCl(4)[P[(C(5)Me(4))(2)]Ph] (M = Mo, Ta), Ir[P[(C(5)Me(4))(2)]Ph](2)(CO)Cl, and CpFe(CO)[PhP[(C(5)Me(4))(2)]]Me. For comparison purposes, derivatives of the related phospholane ligand PhP[Me(2)C(4)H(6)] have also been investigated, including Ph[Me(2)C(4)H(6)]PS, Ir[Ph[Me(2)C(4)H(6)]](2)(CO)Cl, Ir[Ph[Me(2)C(4)H(6)]](2)(CO)Me, Ir[PPh[Me(2)C(4)H(6)]](COD)(Cl), and Pd[P[Me(2)C(4)H(6)]Ph][eta(2)-C(6)H(4)C(H)(Me)NMe(2)]Cl. The steric and electronic properties of PhP[(C(5)Me(4))(2)] are determined to be intermediate between those of PPh(2)Me and PPh(3). Thus, the crystallographic cone angles increase in the sequence PPh(2)Me (134.5 degrees) < PhP[(C(5)Me(4))(2)] (140.2 degrees) < PPh(3) (148.2 degrees), while the electron donating abilities decrease in the sequence PPh(2)Me > PhP[(C(5)Me(4))(2)] > PPh(3). Finally, PhP[(C(5)Me(4))(2)] has a smaller cone angle and is less electron donating than the structurally similar phosphine, PhP[Me(2)C(4)H(6)].

Renal biopsy in elderly patients: clinicopathological correlation in 117 Korean patients

AIM

In the elderly with renal disease, the clinical presentations are frequently inconsistent with the pathologic findings. We tried to clarify the differences in pathological findings between the young and the elderly, in Korea and in Western countries, and the usefulness of a percutaneous renal biopsy in the elderly with renal disease.

PATIENTS AND METHODS

We analyzed the clinical presentations and spectrums of renal histopathology by reviewing medical records and renal biopsy reports retrospectively in 117 Korean patients aged 60 years or more with renal disease.

RESULTS

85 patients had primary renal disease. The remaining 32 patients had renal diseases associated with systemic conditions. Out of the 85 patients with primary renal disease, 61 cases presented as idiopathic nephrotic syndrome. Compared with renal biopsy results of younger adult patients (age 15-59, n = 1,908), membranous nephropathy, crescentic glomerulonephritis, membranoproliferative glomerulonephritis, amyloidosis, light chain disease, and thrombotic thrombocytopenic purpura were more prevalent, but IgA nephropathy and lupus nephritis were less common in the elderly patients. In clinical presentation, nephrotic syndrome and rapidly progressive renal failure were more prevalent, but asymptomatic urinary abnormality was less common in elderly patients. The responsiveness to treatment was good in elderly patients with minimal-change lesion (complete remission in all patients) but poor in crescentic glomerulonephritis, IgA nephropathy, and membranoproliferative glomerulonephritis. From the above findings, the clinical presentation, patterns of histopathology and responsiveness to treatment of elderly Korean patients were similar to those of the younger Korean control group and the Western elderly group.

CONCLUSION

Percutaneous renal biopsy is a useful diagnostic aid and can be used as a therapeutic guideline even in elderly patients with renal disease.

Activation of the IGF-II gene by HBV-X protein requires PKC and p44/p42 map kinase signalings

We have recently shown that HBx protein, one of the causative agents of hepatocellular carcinomas, regulates Sp1 mediated transcription of insulin-like growth factor II promoter 4 (Lee et al. (1998) Oncogene 16, 2367-2380). Here we show that PKC and p44/p42MAPK signalings are required for the HBx-induced Sp1-mediated IGF-II P4 transcriptional activity since (i) PKC activation by PMA or PKC expression vector increases Sp1 phosphorylation and P4 activity in HBx-transfected HepG2 cells; (ii) PKC inhibition by PKC inhibitor Gö6976 reduces Sp1 phosphorylation, P4 activity, and IGF-II mRNA in HBx-transfected HepG2 cells; and (iii) the inhibition of MEK activation by U0126 reduces Sp1 phosphorylation, P4 activity and IGF-II mRNA in HBx-transfected HepG2 cells. These results demonstrate that PKC and p44/p42 MAPK cascades are the essential signaling pathways in Sp1-mediated IGF-II gene activation by HBx.

Choroid plexus papilloma in the posterior cranial fossa: MR, CT, and angiographic findings

In this study, we reviewed the magnetic resonance (MR, n=5), computed tomography (CT, n=3), and angiography (n=3) of six patients with pathologically confirmed choroid plexus papilloma (CPP) in the posterior cranial fossa. CPPs in the posterior cranial fossa have several features, including a propensity to arise at the foramen of Luschka with extraventricular extension, occasional peritumoral signal voids/cysts or calcification, weaker enhancement on MR or CT, and less strong tumor staining by the anterior or posterior inferior cerebellar artery or angiography.

A Preliminary Report of the Virtual Craniofacial Center: Development of Internet-/Intranet-Based Care Coordination of Pediatric Craniofacial Patients

The authors present preliminary information regarding the development of an Internet-based Virtual Craniofacial Center that provides access to a patient database with visual and textual data. Patients are photographed by digital camera with standardized images. Through a Web site linked to a remote database, patient demographics, management data, reports, and acquired digital photographic images are stored and retrieved. The database can be used to sort and to present data as desired by multiple specialists. Confidentiality is maintained by unique identification numbers and password access to the server for craniofacial team members. The current system uses economical equipment (i.e., digital camera, personal computer with modem, and access to a remote Windows NT-based server), using data that can be entered in a variety of cross-platform personal computer systems and transmitted on a wide range of bandwidths-from a relatively low-bandwidth (28.8 KB per second) modem to a high-speed T-3 line connection. Long-term goals include archival data storage and analysis, as well as the development of multicenter telemedicine links for active craniofacial centers.

Repair of cartilage defect in the rabbit with cultured mesenchymal stem cells from bone marrow

In 16 mature New Zealand white rabbits mesenchymal stem cells were aspirated from the bone marrow, cultured in monolayer and implanted on to a full-thickness osteochondral defect artificially made on the patellar groove of the same rabbit. A further 13 rabbits served as a control group. The rabbits were killed after 14 weeks. Healing of the defect was investigated histologically using haematoxylin and eosin and Safranin-O staining and with immunohistochemical staining for type-II collagen. We also used a reverse transcription-polymerase chain reaction (RT-PCR) to detect mRNA of type-I and type-II collagen. The semiquantitative histological scores were significantly higher in the experimental group than in the control group (p < 0.05). In the experimental group immunohistochemical staining on newly formed cartilage was more intense for type-II collagen in the matrix and RT-PCR from regenerated cartilage detected mRNA for type-II collagen in mature chondrocytes. These findings suggest that repair of cartilage defects can be enhanced by the implantation of cultured mesenchymal stem cells.

Spinal epidural extraskeletal Ewing sarcoma: MR findings in two cases

SUMMARY

We report the CT myelography and MR findings of two cases of extraskeletal Ewing sarcoma involving the spinal epidural and paravertebral spaces in a middle-aged man (case 1) and a young woman (case 2). In both cases CT myelography showed epidural and paravertebral masses on one side, with widening of the ipsilateral neural foramina at the C5-C6 level in case 1 and at the C7-T1 level in case 2. On MR images, the masses were isointense to muscle on T1-weighted images, hyperintense on T2-weighted images, and showed moderate enhancement on contrast-enhanced T1-weighted images. In one case, all pulse sequences showed linear signal voids, representing the vertebral artery encasement within the mass. The intradural component connected with the main mass was detected in the other case.

Electrophoretic karyotype analysis of sequential Candida parapsilosis isolates from patients with persistent or pecurrent fungemia

We assessed the genetic relatedness of sequential isolates of Candida parapsilosis during persistent or recurrent fungemia and the effect of central venous catheter (CVC) removal. Serial isolates of C. parapsilosis were obtained from 17 patients with persistent or recurrent fungemia over periods of up to 5 months. Forty-eight C. parapsilosis isolates from the blood of 17 patients were analyzed by electrophoretic karyotyping (EK) with pulsed-field gel electrophoresis (PFGE), revealing 25 different karyotypes. The strains sequentially isolated from each of seven patients whose fungemia resolved following CVC removal had the same karyotype. Two patients with fungemia that cleared without CVC removal each had two sequential isolates with different karyotypes. In six (75%) of the eight patients whose fungemia was recurrent even after CVC removal, the karyotypes of the pre- and post-CVC removal isolates were different, implying the emergence of a new strain. Overall, the sequential strains from each patient had identical karyotypes in 53% (9 of 17) of the patients and two different karyotypes in 47% (8 of 17). This study shows that EK with PFGE is useful for investigating persistent or recurrent fungemia due to C. parapsilosis and that recurrent fungemia due to C. parapsilosis is more likely caused by reinfection with a second strain.

Syntheses and evaluation of pyrido[2,3-dlpyrimidine-2,4-diones as PDE 4 inhibitors

The syntheses and in vitro evaluation of a new series of pyrido[2,3-d]pyrimidine-2,4-diones bearing substituents at C-3 and/or C-4 positions on the pyridine ring are described. Some of these compounds, especially 51 and 6f, were found to be potent phosphodiesterase 4 (PDE 4) inhibitors exhibiting improved ratio of PDE 4 inhibitory activity:rolipram binding assay (RBA).

Spinal epidural cavernous hemangioma: MR findings

PURPOSE

Cavernous hemangiomas with a spinal epidural location are very uncommon vascular tumors in contrast to those in the vertebral body. The purpose of this study was to describe the radiologic findings, focusing on the MR studies, of spinal epidural cavernous hemangiomas.

METHOD

Five pathologically proven cases of spinal epidural cavernous hemangioma were retrospectively reviewed. MR (n = 5) and CT (n = 1) were evaluated.

RESULTS

The level was thoracic (n = 4) or lumbosacral (n = 1). The mass was located in the epidural space and showed paravertebral extension in all cases. It showed a lobulated contour in all cases and encircled the spinal cord partially with a larger posterior (n = 3) or anterior (n = 1) component in four cases. In all cases, the mass showed high signal intensity on T2-weighted images and homogeneous, strong enhancement. Adjacent bony erosion (n = 5) and intervertebral neural foraminal widening (n = 4) were common.

CONCLUSION

Spinal epidural cavernous hemangioma shows characteristic MR findings of a lobulated contoured epidural mass partially encircling the spinal cord with a larger posterior component in the spinal canal, high signal intensity on T2-weighted images, and homogeneous, strong enhancement.

Parapharyngeal second branchial cyst manifesting as cranial nerve palsies: MR findings

SUMMARY

We report the MR findings of parapharyngeal branchial cleft cyst manifesting as multiple, lower cranial nerve palsies in a 35-year-old woman. On MR images, a well-marginated cystic mass was detected in the right parapharyngeal space, with displacement of both the right internal carotid artery and the right internal jugular vein on the posterolateral side. The cyst contained a whitish fluid that was slightly hyperintense on T1-weighted images and slightly hypointense to CSF on T2-weighted images. No enhancement on contrast-enhanced T1-weighted images was present. The right side of the tongue showed high signal intensity on T2-weighted images, suggesting denervation.

Lymphonodular cryptococcosis diagnosed by fine needle aspiration cytology in hyper-IgM syndrome. A case report

BACKGROUND

Most cases of cryptococcosis are diagnosed when signs of meningitis have appeared. We report a case of lymphonodular cryptococcosis that was diagnosed by fine needle aspiration cytology (FNAC), excisional biopsy of a cervical lymph node and culture of aspirated material.

CASE

An 11-year-old boy presented with a history of fever and enlarged bilateral cervical lymph nodes of two weeks' duration. Past medical history included immunoglobulin replacement for hyper-IgM syndrome for the previous eight years. FNAC smears from a cervical lymph node showed numerous yeasts of various sizes, ranging from 5 to 15 microns in diameter, located in the cytoplasm of multinucleated giant cells and in the background. In air-dried, Diff-Quik-stained slides, the yeasts stained blue and were surrounded by clear halos. Aspirated material collected in the syringe was cultured, and Cryptococcus neoformans was isolated.

CONCLUSION

This case report suggests that a combination of FNAC and culture is a simple and useful method of diagnosing fungal infections. Early diagnosis by FNAC makes possible the early initiation of treatment.

Repair of cartilage defect in the rabbit with cultured mesenchymal stem cells from bone marrow

In 16 mature New Zealand white rabbits mesenchymal stem cells were aspirated from the bone marrow, cultured in monolayer and implanted on to a full-thickness osteochondral defect artificially made on the patellar groove of the same rabbit. A further 13 rabbits served as a control group. The rabbits were killed after 14 weeks. Healing of the defect was investigated histologically using haematoxylin and eosin and Safranin-O staining and with immunohistochemical staining for type-II collagen. We also used a reverse transcription-polymerase chain reaction (RT-PCR) to detect mRNA of type-I and type-II collagen. The semiquantitative histological scores were significantly higher in the experimental group than in the control group (p < 0.05). In the experimental group immunohistochemical staining on newly formed cartilage was more intense for type-II collagen in the matrix and RT-PCR from regenerated cartilage detected mRNA for type-II collagen in mature chondrocytes. These findings suggest that repair of cartilage defects can be enhanced by the implantation of cultured mesenchymal stem cells.

Application of SCAM (substituted cysteine accessibility method) to gap junction intercellular channels

The pore-lining residues of gap junction channels determine their permeability to ions and small cellular metabolites. These residues can be identified through systematic cysteine substitution and accessibility analysis, commonly known as SCAM (Substituted Cysteine Accessibility Method). However, application of this technique to intercellular channels is more complicated than for their transmembrane counterparts. We have utilized a novel dual-oocyte perfusion device to apply cysteine reagents to the cytoplasmic face of paired, voltage-clamped Xenopus oocytes. In this configuration, a large and irreversible cysteine reagent MBB (maliemidobutyryl biocytin, mw 537) was shown to readily traverse the gap junction pore and induce conductance changes upon reaction of accessible sites. Of the 11 reactive sites identified, 6 were located in M3, where they span the bilayer. They display a periodicity characteristic of the tilted helix that lines the pore in the gap junction structure of Unger et al. (1999). Access to several of the other sites was attributed to aqueous crevices between transmembrane helices. Reactive sites were slightly different than those identified for gap junction hemichannels (Zhou et al. 1997), suggesting that conformational changes occur upon docking.

Vertebral artery dissection: spectrum of imaging findings with emphasis on angiography and correlation with clinical presentation

A study was performed to evaluate the relationship between the imaging features and clinical presentation of vertebral artery (VA) dissection. Twenty-two patients with 24 VA dissections at angiography and clinical evaluation also underwent computed tomography and magnetic resonance imaging. The angiographic patterns of VA dissection were categorized as aneurysmal (n = 10) or steno-occlusive (n = 14). All 10 patients (10 lesions) with the aneurysmal pattern had dissection in the V4 (intradural) segment and presented with headache (n = 5), neurologic deficit (n = 2), dizziness (n = 2), or altered mentality (n = 1). However, the 12 patients (14 lesions) with the steno-occlusive pattern had dissection from the V1 segment to the V4 segment and presented with neurologic deficits caused by infarction of an embolic nature. Overall, the most frequent VA dissection site was the V4 segment. The distribution of the dissection sites and the clinical presentation tended to differ according to the angiographic patterns of aneurysm or stenosis-occlusion.

T-butyl hydrogen peroxide increases the activities of the Maxi-K channels of rat brain

In this study, we investigated the effects of tertiary-butyl hydrogen peroxide (tBHP) on the large-conductance Ca2+-activated K+ (Maxi-K) channel of rat brain using lipid bilayer. When tBHP was applied to the cytosolic side, the open probability (Po) of both fast- and slow-gating Maxi-K channels increased within 1 min in dose-dependent manner. tBHP effects did not reverse immediately, suggesting tBHP induces some chemical modification on the channel protein. From kinetic analysis of single channel data, the increase in the Po appears to be mainly due to shortening of closed dwell time in both types of the Maxi-K channels. 50 microM diamide, a sulfhydryl-specific oxidant, irreversibly decreased the Po. However, further addition of 7.3 mM tBHP still increased the Po, suggesting that tBHP does not share the target for oxidation with diamide.

An arachnoid granulation in the straight sinus

We report CT, MRI and angiographic findings of an arachnoid granulation in the straight sinus in a young man. Its density and signal intensity were isodense and isointense with cerebrospinal fluid on CT and MRI, respectively. The lesion appeared as a filling defect on MR venography and conventional angiography.

A planar pCO2 sensor with enhanced electrochemical properties

To develop planar microchemical pCO2 sensing devices with improved electrochemical properties, we combined two advanced technologies. One is a differential sensor arrangement to simplify the microfabrication procedure by employing pH-sensitive gas-permeable membranes, and the other is the use of an enzyme (carbonic anhydrase) to shorten total measurement time by accelerating the rate of CO2 hydration. The adhesion of the polyurethane-matrix gas-permeable membrane is enhanced significantly by incorporating a silanizing reagent (silicon tetrachloride), improving the stability and extending sensor lifetime. The proposed differential pCO2 microelectrodes exhibited significantly improved performance in their preconditioning period, response and recovery times, stability, response slope, and lifetime.

Multiplex in-cell reverse transcription-polymerase chain reaction for the simultaneous detection of p210 and p190 BCR-ABL mRNAs in chronic myeloid leukemia and Philadelphia-positive acute lymphoblastic leukemia cell lines

We designed a novel multiplex in-cell reverse transcription-polymerase chain reaction method for the simultaneous detection and differentiation of p190 and p210 BCR-ABL mRNAs within single cells from the human chronic myeloid leukemia and Philadelphia positive acute lymphoblastic leukemia. Human K562 chronic myeloid leukemia and SUP B-15 Ph+ acute lymphoblastic leukemia cell lines were used as positive controls for p210 and p190 BCR-ABL mRNAs, respectively. HL60 cell line was used as a negative control. After the leukemia cells were fixed and permeabilized, without extracting nucleic acids, the mRNAs were reverse transcribed to cDNAs, and the cDNAs were amplified by multiplex polymerase chain reaction with fluorescent primers specific for p190 and p210 BCR-ABL mRNAs. After transfer onto glass slides by cytospin, the amplified cells were detected by fluorescence microscopy. Fluorescence microscopy after propidium iodide or 4',6-diamidino-2-phenylindone counterstaining showed that the positive K562 cells exhibited a yellow-green fluorescent cytoplasm around a red nucleus, and that the positive SUP B-15 cells exhibited an orange cytoplasm around a blue nucleus. Only the red or blue nucleus was visible in respective negative HL60 cells. The specificity of amplification was confirmed by the absence of a signal when control experiments were performed either with RNase digestion of mRNA or without reverse transcriptase/Taq polymerase. We conclude that the multiplex in-cell reverse transcription-polymerase chain reaction method is capable of simultaneously detecting and differentiating the p210 and p190 BCR-ABL mRNAs of chronic myeloid leukemia and Philadelphia-positive acute lymphoblastic leukemia cells, and that it may be useful in quantitatively monitoring the minimal residual disease during therapy.

Renal functional responses to centrally administered ouabain in anesthetized rabbits

The effects of intracerebroventricularly administered ouabain on renal function were studied in rabbits. Ouabain, when given intracerebroventricularly in doses ranging from 0.1 to 10 micrograms/kg, dose-dependently produced antidiuretic, antinatriuretic and antikaliuretic effects, along with decreases in renal perfusion and glomerular filtration rate. Systemic blood pressure also increased significantly in a dose-related fashion. No increase in free water reabsorption was noted. Intravenously administered ouabain (10 micrograms/kg) caused less pronounced antidiuresis and antinatriuresis, with the renal hemodynamics tending slightly to decrease. No significant increment of systemic blood pressure with intravenous ouabain was observed. In rabbits with one kidney denervated and the contralateral left intact, ouabain 10 micrograms/kg i.c.v. produced the typical renal effects on the intact kidney, while the denervated kidney responded with prominent natriuresis and diuresis, showing the maximal response in the second 10-min period after administration. Renal nerve activity increased significantly upon administration of ouabain 10 micrograms/kg i.c.v. and reached a peak at around 10 to 20 min after drug administration, a period in which the most remarkable antidiuresis and antinatriuresis is produced by i.c.v. ouabain. These observations suggest that the antidiuresis and antinatriuresis elicited by centrally administered ouabain results mainly from the decrease of renal hemodynamics, which is caused by the increased renal nerve activity.

Castleman's disease in the retropharyngeal space: CT and MR imaging findings

We report CT and MR imaging findings in a case of Castleman's disease involving the retropharyngeal space in a middle-aged woman. On CT scans, a well-marginated, homogeneous, and densely enhancing mass was detected in the right retropharyngeal space. The mass was isointense to the muscle on T1-weighted MR images, hyperintense to the muscle on T2-weighted MR images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted MR images. The linear hypointense signal in an arborizing pattern was observed within the mass on all pulse sequences.

Synthesis of tetrakis(multifluoro-4-pyridyl)porphin derivatives as acetylcholinesterase inhibitors

New tetrakis(multifluoro-4-pyridyl)porphin derivatives (2-4) and water soluble porphyrin (5) were synthesized to investigate their interactions with acetylcholinesterase from electric eel. These compounds have been found to be the potent reversible inhibitors of the enzyme with Ki values of microM range. In addition, porphyrin (5) showed broad spectrum of anticancer activities.

Aroma-active compounds of miniature beefsteakplant (Mosla dianthera Maxim)

Volatile flavor compounds of miniature beefsteakplant (Mosla dianthera Maxim.) from Vietnam were analyzed through gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Sixty-two compounds were identified by GC-MS. Of these, (+/-)-carvone and (+/-)-limonene were the most abundant, followed by (Z)-limonene oxide, beta-caryophyllene, and alpha-humulene. Twenty aroma-active compounds were detected by aroma extract dilution analysis conducted on two GC columns of different polarities (DB-5MS and DB-Wax). The most intense aroma-active compounds were linalool (floral/sweet/lemon), (-)-carvone (spearminty), and 1-octen-3-one (mushroom/earthy). Other predominant aroma-active compounds included (Z)-3-hexenol (grassy/leafy/metallic), (Z)-limonene oxide (lemon/floral), myrcene (plastic/sweet), (+)-limonene (orange/lemon), alpha-thujene (soy sauce/grassy), and (Z)-dihydrocarvone (spearminty/pepperminty). On the basis of the aroma characteristics and intensity, it was concluded that (-)-carvone was responsible for the characteristic aroma of miniature beefsteakplant.

Spontaneously infected cephalohematoma: case report and review of the literature

Spontaneously infected cephalohematomas are rare occurrences; only five cases have been reported previously. Uninfected cephalohematomas are common and usually resolve without treatment. However, physicians should be aware that cephalohematomas are potential sites for infection and may require aspiration for diagnosis and treatment. Untreated infected cephalohematomas may lead to osteomyelitis, epidural abscess, or subdural empyema. We present a case of a spontaneously infected cephalohematoma with an associated osteomyelitis which was successfully managed with drainage and long-term antibiotics. A review of the literature is also presented.

Genetic variation of the Apo Al-CIII-AIV gene cluster in hypertriglyceridemic patients with chronic renal failure undergoing hemodialysis

Many patients with chronic renal failure (CRF) requiring hemodialysis present with hypertriglyceridemia (HTG). But the exact cause of HTG in CRF is still unknown. Genetic variation of the apo AI-CIII-AIV gene cluster was reported to be associated with primary HTG, atherosclerosis and coronary artery disease. This study was designed to evaluate the association between the restriction fragment length polymorphism (RFLP) of the apo AI-CIII-AIV gene cluster and HTG in patients with CRF undergoing hemodialysis. Genetic variations of the apo AI-CIII-AIV gene cluster were analysed in peripheral leukocyte samples from 59 patients with CRF undergoing hemodialysis: 17 patients with HTG (CRF-HTG) and 42 patients without HTG (CRF-NTG). The RFLP was achieved through the digestion of PCR products by two restriction enzymes, SstI and MspI. The frequency of SstI minor allele (S2) in CRF-HTG was 0.44, which was significantly higher than that in CRF-NTG (0.17). Frequencies of MspI minor allele (M2) in CRF-HTG and CRF-NTG were not significantly different (0.5 vs 0.32) (p=0.07). Frequencies of S2-M2 genotype were 0.65 in CRF-HTG, and 0.27 in CRF-NTG (p<0.005). These data indicate that genetic variation of the apo AI-CIII-AIV gene cluster may serve as one of the causes of HTG in CRF.

Production and characterization of biologically active human GM-CSF secreted by genetically modified plant cells

Human granulocyte-macrophage colony-stimulating factor (GM-CSF), a hemopoietic growth factor, was produced and secreted from tobacco cell suspensions. The GM-CSF cDNA was carried by a binary vector under the control of the CaMV 35S promoter and the T7 terminator. In addition, a 5'-nontranslated region from the tobacco etch virus (TEV leader sequence) was fused to the N-terminal end of the GM-CSF transgene. For ease of purification, a 6-His tag was added to the 3' end of the GM-CSF cDNA. Addition of the TEV leader sequence increased protein production more than twofold compared to non-TEV controls. Initial batch cultivation studies indicated a maximum of 250 microg/L extracellular and 150 microg/L intracellular GM-CSF. Western blot analysis detected multiple peptides with masses from 14 to 30 kDa in the extracellular medium. The plant-produced GM-CSF was biologically active and could be bound to a nickel affinity matrix, indicating that both the receptor-binding region and the 6-His tag were functional. The batch production of GM-CSF was compared with the production of other recombinant proteins secreted by transformed tobacco cells. The recovery of secreted GM-CSF was increased by the addition of stabilizing proteins and by increasing salt in the growth medium to physiological levels.

Acute cerebral phaeohyphomycosis due to Wangiella dermatitidis accompanied by cerebrospinal fluid eosinophilia

We report a case of cerebral phaeohyphomycosis due to Wangiella dermaitidis in an immunocompetent adult man. His cerebrospinal fluid (CSF) showed pleocytosis with a high eosinophil count but without peripheral blood eosinophilia. The present case suggested that this black yeast-like fungus should be included when the causes of CSF eosinophilia are considered, even though it is an extremely rare pathogen.

Nosocomial cluster of Candida lipolytica fungemia in pediatric patients

Candida lipolytica has rarely been reported as a human pathogen. An apparent outbreak of Candida lipolytica fungemia (n = 5 cases) occurred in a pediatric ward over a 9-week period. The five patients infected were hospitalized in three adjacent rooms and cared for by the same healthcare workers. The index patient had central venous catheter-related fungemia, whereas the second patient, who was in the adjacent single room, had transient fungemia. Three additional cases of fungemia occurred in patients with hematological disorders who shared the same room; all three patients had central venous catheters and had been receiving oral fluconazole prophylaxis (50 mg/day for more than 3 weeks) at the time of infection. In vitro susceptibility testing of the strains showed that the MIC of fluconazole for all the isolates was 32 microg/ml. Random amplified polymorphic DNA analysis provided evidence of the clonal origin of the isolates, but the source of the outbreak was not identified. All four patients with persistent fungemia were successfully treated via catheter removal or empiric amphotericin B treatment. This outbreak shows the potential for the nosocomial epidemic transmission of Candida lipolytica.

Spinal intradural capillary hemangioma: MR findings

We report a case of a spinal intradural capillary hemangioma. On MR images, a well-circumscribed intradural mass was detected at the T8-T9 level. The signal intensity of the mass relative to the spinal cord was isointense on T1-weighted images, hyperintense on T2-weighted images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted images. The mass had both extramedullary and intramedullary components.

Psoralen-ultraviolet A-induced erythema: sensitivity correlates with the concentrations of psoralen in suction blister fluid

Since the advent of psoralen-ultraviolet A (PUVA) therapy, the value of plasma 8-methoxypsoralen (8-MOP) concentrations to predict PUVA-induced erythema has been widely investigated. Plasma 8-MOP concentrations have not been proportional to, and cannot alone predict, the degree of PUVA-induced erythema. We assumed that PUVA-induced erythema was related more closely to psoralen concentrations in the skin tissue rather than those within blood vessels. This study was designed to investigate the correlations between the 8-MOP concentrations in suction blister fluid (SBF) and in plasma, with the degree of PUVA-induced erythema. 8-MOP concentrations in plasma and SBF were measured in 15 vitiligo patients and 11 volunteers. Blood and SBF samples were collected 2 h after taking 8-MOP, and 8-MOP concentrations in plasma and SBF were quantified using reverse-phase high-performance liquid chromatography. Eleven volunteers were phototested using a series of doses of ultraviolet A at the time of sampling. The erythema responses were estimated visually to determine the minimal phototoxic dose (MPD). SBF 8-MOP concentrations showed a weak positive correlation with plasma 8-MOP concentrations, which means that we could not predict the exact SBF 8-MOP concentrations using the plasma 8-MOP concentrations. The MPD showed a better correlation with the log of the SBF 8-MOP concentration than with that of the plasma 8-MOP concentration. These results show that plasma 8-MOP concentration cannot represent the exact SBF 8-MOP concentration, and that SBF 8-MOP concentrations, which are representative of the skin tissue 8-MOP level, are more closely related to the erythemal sensitivity during PUVA therapy.

Novel mutations of the PKD1 gene in Korean patients with autosomal dominant polycystic kidney disease

The gene for the most common form of autosomal dominant polycystic kidney disease (ADPKD), PKD1, has recently been characterized and shown to encode an integral membrane protein, polycystin-1, which is involved in cell-cell and cell-matrix interactions. Until now, approximately 30 mutations of the 3' single copy region of the PKD1 gene have been reported in European and American populations. However, there is no report of mutations in Asian populations. Using the polymerase chain reaction and single-strand conformation polymorphism (SSCP) analysis, 91 Korean patients with ADPKD were screened for mutation in the 3' single copy region of the PKD1 gene. As a result, we have identified and characterized six mutations: three frameshift mutations (11548del8bp, 11674insG and 12722delT), a nonsense mutation (Q4010X), and two missense mutations (R3752W and D3814N). Five mutations except for Q4010X are reported here for the first time. Our findings also indicate that many different mutations are likely to be responsible for ADPKD in the Korean population. The detection of additional disease-causing PKD1 mutations will help in identifying the location of the important functional regions of polycystin-1 and help us to better understand the pathophysiology of ADPKD.

Degeneration of the acetabular cartilage in osteonecrosis of the femoral head: histopathologic examination of 15 hips

Acetabular cartilage with subchondral bone was taken from the superior dome from 15 hips of 13 patients undergoing total hip arthroplasty due to osteonecrosis of the femoral head. The mean age of the patients was 40 years. There were 10 hips ARCO stage IIIA, and 5 hips stage IIIB. 3 of the cases were mild, 12 moderate, and 1 had severe arthrosis. The degree of collapse of the femoral head was significantly related to the degeneration of the acetabular cartilage on histological examination. Our observations support the view that patients with an ARCO Stage III hip do not benefit from head-preserving procedures. They may also explain why bipolar prosthesis gives poorer results than total hip arthroplasty, in cases of osteonecrosis of the femoral head.

Nonocclusive mesenteric ischemia in a patient on maintenance hemodialysis

Nonocclusive mesenteric ischemia (NOMI) is known to occupy about 25% to 60% of intestinal infarction. NOMI has been reported to be responsible for 9% of the deaths in the dialysis population and the postulated causes of NOMI include intradialytic hypotension, atherosclerosis and medications, such as diuretics, digitalis and vasopressors. Clinical manifestations, such as fever, diarrhea and leukocytosis, are nonspecific, which makes early diagnosis of NOMI very difficult.

CASE

A 66-year-old woman on maintenance hemodialysis for 5 years was admitted with syncope, abdominal pain and chilly sensation. Since 7 days prior to admission, blood pressure on the supine position during hemodialysis had frequently fallen to 80/50 mmHg. Four days later, she complained of progressive abdominal pain. Rebound tenderness and leukocytosis (WBC 13900/mm3) with left shift were noted. Stool examination was positive for occult blood. Abdominal CT scan showed a distended gall bladder with sludge. Under the impression of acalculous cholecystitis, she was operated on. Surgical and pathologic findings of colon colon were compatible with NOMI. Because of recurrent intradialytic hypotension, we started midodrine 2.5 mg just before hemodialysis and increased the dose up to 7.5 mg. After midodrine therapy, blood pressure during dialysis became stable and the symptoms associated with hypotension did not recur.

CONCLUSION

As NOMI may occur within several hours or days after an intradialytic hypotensive episode, abdominal pain should be carefully observed and NOMI should be considered as a differential diagnosis. In addition, we suggest that midodrine be considered to prevent intradialytic hypotensive episodes.