Prevention of infection in dental procedures

The efficacy of a newly-developed anti-cross-contamination device in dentistry, the Air Flushing Clean System (AFCS), was tested under experimental and clinical conditions. In the experimental situation, a dental air turbine handpiece with or without AFCS was contaminated with two bacterial strains, Staphylococcus aureus FDA209P and Streptococcus mutants ATCC25175. After contamination with these bacteria, the handpieces were subjected to two disinfecting methods. Residual bacteria inside the handpiece or an air/water line were cultured and counted, and compared with controls. In this experiment, with AFCS but no dental vacuum suction, wiping of the handpiece with 70% ethanol gauze reduced the count of S. aureus by 99%. No bacterial contamination in the air/water line was detected after exchanging with an autoclaved handpiece. With AFCS and dental vacuum suction, bacterial contamination in the air/water line, as well as in the interior of the handpiece, was not detected. These results indicate that AFCS could reduce bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece regardless of whether or not the dental vacuum suction was used.

The sticking probability of a hydrogen atom on icy mantle

In the present work, we investigate the sticking process of a hydrogen atom on the surface of dust grains. As a realistic model for the icy mantle of dust grains, we produced slab-shaped amorphous water ice with infinite area by classical molecular dynamics (MD) computational simulation using two-dimensional periodic boundary condition. The resulting amorphous water ice slabs at 10 K and 70 K were found to be in good agreement with the experimental high-density and low-density amorphous water ice, respectively. Then, we investigated the dynamical behaviors of an impinging H atom on the surface of it by MD simulations. The sticking probabilities of incident H atoms with several initial temperatures on 10 K and 70 K ice were obtained. It was found that most of H atoms colliding with the 10 K ice stuck on the surface of it. After having stuck, the impinging H atoms diffused on the surface of ice and became trapped in one of potential wells on the surface. The mobility of a H atom on the surface of the amorphous water ice was found to depend only upon the temperature of ice.

MR signal intensity changes in hepatic parenchyma with ductal dilation caused by intrahepatic cholangiocarcinoma

MR images of the liver in 13 patients with surgically proven intrahepatic cholangiocarcinoma were reviewed retrospectively and correlated to the histologic analysis of surgical specimens. We paid special attention to the peripheral liver tissue with ductal dilation but without tumorous involvement. High signal intensity was observed in the hepatic parenchyma with ductal dilation on T1-weighted spin-echo images (8 of 12) and spoiled gradient-recalled echo images (seven of seven), as compared with the contralateral hepatic lobe without duct dilation. The high signal intensity was not suppressed with fat saturation and showed enhancement after administration of contrast (11 of 12). Concurrent portal venous obstruction did not have significant effect on these findings (P < .05). Correlation with pathologic specimens suggested that this enhancement was associated with periportal fibrosis. The etiology of the high signal intensity on unenhanced spin echo or gradient-recalled T1-weighted image remains unclear. Radiologists should recognize these findings and should distinguish these from tumor involvement or the arterial buffer response caused by portal venous obstruction.

B cell epitope mapping of the bacterial superantigen staphylococcal enterotoxin B: the dominant epitope region recognized by intravenous IgG

We showed that i.v. IgG contains Abs against a major group of bacterial superantigens, and that they can inhibit superantigen-elicited T cell activation. The B cell epitope region of the superantigen and the inhibitory mechanism have remained unknown. To analyze the dominant B cell epitopes on the bacterial superantigen SEB (staphylococcal enterotoxin B), we constructed fusion proteins of SEB deletion mutants, and the reactivities of these recombinant proteins to i.v. IgG and healthy human sera were evaluated by means of immunoblotting. Intravenous IgG and healthy human sera mostly recognized the C-terminal fragment (amino acid (aa) 133-239). The C-terminally truncated protein (aa 1-228) and the truncated mutant delta 225-234 lost reactivity, while the truncated protein (aa 1-234) did not, suggesting that the region (aa 225-234) is the dominant B cell epitope. The mutant, in which residues 226-229 of SEB were exchanged for residues 209-212 of streptococcal pyrogenic exotoxin A, reduced the reactivity with the C-terminal region-specific IgG purified by affinity chromatography. The C-terminal region-specific IgG inhibited SEB-elicited T cell activation, suggesting that this Ab that recognizes the epitope functions as the humoral defensive factor against SEB in humans. Furthermore, the assumed epitope region was homology to the residues (aa 32-41) of human thymopoietin, containing the biologic active site.

B cell epitope mapping of the bacterial superantigen staphylococcal enterotoxin B: the dominant epitope region recognized by intravenous IgG

We showed that i.v. IgG contains Abs against a major group of bacterial superantigens, and that they can inhibit superantigen-elicited T cell activation. The B cell epitope region of the superantigen and the inhibitory mechanism have remained unknown. To analyze the dominant B cell epitopes on the bacterial superantigen SEB (staphylococcal enterotoxin B), we constructed fusion proteins of SEB deletion mutants, and the reactivities of these recombinant proteins to i.v. IgG and healthy human sera were evaluated by means of immunoblotting. Intravenous IgG and healthy human sera mostly recognized the C-terminal fragment (amino acid (aa) 133-239). The C-terminally truncated protein (aa 1-228) and the truncated mutant delta 225-234 lost reactivity, while the truncated protein (aa 1-234) did not, suggesting that the region (aa 225-234) is the dominant B cell epitope. The mutant, in which residues 226-229 of SEB were exchanged for residues 209-212 of streptococcal pyrogenic exotoxin A, reduced the reactivity with the C-terminal region-specific IgG purified by affinity chromatography. The C-terminal region-specific IgG inhibited SEB-elicited T cell activation, suggesting that this Ab that recognizes the epitope functions as the humoral defensive factor against SEB in humans. Furthermore, the assumed epitope region was homology to the residues (aa 32-41) of human thymopoietin, containing the biologic active site.

MR imaging of hepatocellular carcinomas: effect of Cu and Fe contents on signal intensity

BACKGROUND

To elucidate the metallic factors contributing to the signal intensities of hepatocellular carcinoma (HCC) on T1-weighted magnetic resonance (MR) images and to determine whether or not changes in signal intensity contribute to the diagnosis of histological grading of HCC.

METHODS

In 35 patients immediately after surgery, the quantities of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) were determined in HCCs and the surrounding hepatic parenchyma. The correlations among these findings, the histopathological findings, and the signal intensities of T1-weighted MR images were evaluated.

RESULTS

Among the 35 HCCs, 12 (34%) were of high intensity, 14 (40%) were isointense, and 9 (26%) were of low intensity on T1-weighted images versus the surrounding hepatic parenchyma. The paramagnetic ions, which contributed to the signal intensity patterns, were assumed to be Cu in HCCs (30.5 +/- 52.9 microg/g ww), and Fe in the livers (106.2 +/- 86.8 microg/g ww) and HCCs (87.7 +/- 49.1 microg/g ww). In 12 HCCs with high intensity, one was grade I, eight were grade II, and three were grade III according to Edmondson-Steiner's histopathological classification.

CONCLUSIONS

Signal intensity and signal intensity patterns alone cannot be signs of low-grade malignancy because of the Fe in livers and in HCCs.

Positron emission tomography (PET) in Machado-Joseph disease

Positron emission tomography studies on the regional cerebral glucose metabolism (rCMRglc) and 18F-fluorodopa (18F-Dopa) uptake were performed in 3 patients with Machado-Joseph disease (MJD), a dominantly inherited degenerative disease in the cerebellum, brainstem and basal ganglia. The rCMRglc in MJD was found to be significantly decreased in the cerebellum, brainstem, striatum and whole cerebral cortex in comparison to that in normal subjects. These results of rCMRglc were different from those for dominantly inherited olivopontocerebellar atrophy (dOPCA) or cerebellar cortical degeneration (CCD), however they were similar to those for sporadic olivopontocerebellar atrophy (sOPCA) and multiple system atrophy (MSA). The 18F-Dopa uptake in MJD was found to be significantly decreased in the putamen and relatively spared in the caudate, which was different from that of MSA. In addition, these results indicate that MJD showed a dysfunction, not only in the regions with apparent pathological involvement such as cerebellum, brainstem and nigro-striatal dopaminergic system, but also in the cerebral cortex and the striatum where no pathology could be observed using conventional morphological techniques.

Vimentin-positive adenocarcinomas of the stomach: co-expression of vimentin and cytokeratin

Recently, the expression of vimentin has been reported in some carcinomas. This study was designed to clarify the significance of vimentin expression in solid type poorly differentiated adenocarcinomas of the stomach. Immunohistochemically, 239 poorly differentiated adenocarcinomas with solid components of the stomach were stained for vimentin. Vimentin-positive cases were also stained by CAM 5.2 using serial mirror sections. We found 15(6.3%) vimentin-positive cases. Twelve of them demonstrated varying amounts of rhabdoid-like cells. Eight cases diffusely co-expressed vimentin and cytokeratin simultaneously. In addition, four co-expressing cases showed positive staining with Keratin-903 which recognizes the high molecular-weight cytokeratin. Most of the co-expressing cases showed a diffuse proliferation of polygonal tumour cells with focal cell-to-cell contact. The prognosis of the co-expressing cases was poor in comparison with that of the 89 vimentin-negative tumours (P < 0.05).

[Current topics in glaucoma]

Among the many factors involved in the development of glaucoma, the elevation of intraocular pressure (IOP) is the most important. The treatment of glaucoma aims to lower IOP in order to maintain visual function. New anti-glaucoma drugs, latanoprost and nipradilol, have been shown to effect a reduction in IOP equal to that achieved with the equivalent dosage of timolol, with no adverse systemic side effects. The mechanism of the reduction of IOP by these drugs mainly involves the increase of uveoscleral outflow. The success rate of filtering surgery for glaucoma has been increased by using antimetabolites such as mitomycin C (MMC) and 5-fluorouracil (5-FU). The use of MMC during surgery has resulted in a better outcome than with 5-FU. Normal tension glaucoma (NTG) cases are reported to constitute more than 60% of total glaucoma cases in Japan. NTG is different from primary open-angle glaucoma not only in IOP but also in the pattern of the visual field defect, cupping and peripapillary atrophy of the optic nerve head (ONH). The first choice of treatment for NTG is using drugs for reducing IOP and, if necessary, argon laser trabeculoplasty. In addition to these treatments a drug for increasing the blood circulation in the brain, brovinecamine fumarate, has shown beneficial effects in the treatment of NTG. NTG patients whose visual field can be shown by static perimetry to be deteriorating are indicated for filtering surgery. The results of filtering surgery for NTG have been confirmed that it is more effective than drugs for maintaining the visual field. We have developed an instrument using the laser speckle phenomenon for determining the microcirculation in the eye, as well as in the ONH, noninvasively, quantitatively, and repetitively. With the same instrument, the effects of anti-glaucomadrugs on ocular circulation, especially in the ONH, can also be determined. Timolol has no effect on the circulation in the ONH, but carteolol and betaxlol increase the circulation significantly. The Ca(+2)-blocker, nilvadipine, increases the circulation in the ONH. These findings indicate that the drugs increasing the ONH circulation many be beneficial for the control of glaucoma.

Glucose metabolism in the cortical and subcortical brain structures in multiple system atrophy and Parkinson's disease: a positron emission tomographic study

The brain glucose metabolism was studied by PET with 18F-FDG in 11 patients with multiple system atrophy (MSA) and 12 patients with idiopathic Parkinson's disease (PD). Seven of the 11 MSA patients were diagnosed as having olivopontocerebellar atrophy, two had striatonigral degeneration, while two demonstrated Shy-Drager syndrome. The glucose metabolic rates for each region in the PD patients showed no difference from the normal controls. The frontal, temporal and parietal cortical glucose metabolic rates and the caudate, the putaminal, the cerebellar and the brainstem glucose metabolic rates in the MSA patients decreased significantly from the controls. The atrophy of the cerebellum and the brainstem in the MSA patients were scored by MRI. The cerebellar and brainstem glucose metabolism in the MSA patients decreased as the atrophy score in such regions advanced in each group; however, some patients with no atrophy showed a decreased glucose metabolism. Although the cerebellar and the brainstem glucose metabolism decreased in all MSA patients, such a decrease was not observed in the SND patients. The decrease in the glucose metabolism for the non-cortical regions in the MSA patients seems to be due to a diffuse depletion of the neurons not restricted to the nigrostriatal neurons. Deafferentation to the cerebral cortices seems to result in a decreased cortical metabolism. The differences in the glucose metabolism between MSA and PD as assessed by PET may be caused by the pathophysiological differences between MSA and PD, and such differences therefore appear to be useful when making a differential diagnosis between MSA and PD. The relative sparing of the brainstem and cerebellar glucose metabolism is considered to be a feature of patients with SND.

[Effectiveness of the radioactive strontium (89Sr) chloride agent, SMS.2P for pain palliation in patients with metastatic bone tumor in phase III multicenter clinical trial]

The phase III clinical trial of strontium-89 chloride agent (SMS.2P) was performed in 90 patients with painful bone metastases secondary to prostate (53), breast (18) and other types of cancer (19). Some patients experienced a transient increase in pain or nausea and vomiting. However both symptoms subsided and serious side effects were not observed in any of the patients. As reported, we confirmed some abnormal changes in peripheral blood picture. A decrease in the number of white blood cells and platelets was considered to be partly a result of bone marrow suppression due to 89Sr irradiation. Pain was substantially improved after 89Sr therapy in 58% of the patients and there was some alleviation in 12%. The release from pain was accompanied by an improved quality of life for these patients including sleep patterns and morbidity. Some patients were able to resume their former life styles. Most of the improved patients experienced pain relief from days to one week following 89Sr therapy and in half cases, this remained effective for 2 or 3 months. There were even cases in which the pain relief continued over an observation period of time of clinical study.

V alpha 14+ NK T cells: a novel lymphoid cell lineage with regulatory function

A novel lymphoid lineage, NK T cells, was recently found. The NK T cells are the major population in the periphery comprising 5% of splenic T cells and 40% of bone marrow T cells. They express a unique TCR composed of invariant V alpha 14J alpha 281 and V beta 8.2 together with NK receptor (NKRPI). Surprisingly, the invariant V alpha 14+ TCR is exclusively expressed on NK T cells but not on conventional T cells. As the selective decrease in V alpha 14+ NK T cell population in the periphery is tightly correlated with autoimmune disease development, V alpha 14+ NK T cells control development of autoimmune diseases. We also found that V alpha 14 TCR gene rearrangement and transcripts were detected at an early embryogenesis (d9.5) before the thymus formation. Therefore NK T cells are in the distinct category from conventional T cells. The target of NK T cells is found to be CD1 (class 1b, monomorphic class I MHC-like molecule) present on bone marrow-derived cells and is killed by Fas-FasL interaction or perforin-mediated mechanisms. These results indicate that NK T cells consist of an immunoregulatory system different from defense system in terms of homogeneous repertoire, extrathymic development in early stage of gestation, and their regulatory functional role.

Regulation of bcl-xL expression and Fas susceptibility in mouse B cells by CD40 ligation, surface IgM crosslinking and IL-4

CD40 is one of the key molecules involved in the survival, growth and differentiation of B lymphocytes. In contrast, Fas (Apo-1, CD95) mediates apoptosis of a variety of cell types, including lymphocytes. Recent studies have found that Fas expression on mouse B cells could be strongly induced by CD40 ligation, a helper T cell-derived signal. Here, evidence is provided that CD40 ligation induced two distinct signals: one leading to the upregulation of Fas and the other leading to the enhanced Fas susceptibility. B lymphoma cell lines, CH31 and WEHI279, expressed Fas on cell surfaces, but were resistant to anti-Fas antibody (Ab) induced apoptosis. Treatment with CD40 ligand (CD40L), however, greatly enhanced Fas susceptibility of these cells. Similarly, normal splenic B cells became highly susceptible to Fas-mediated apoptosis following prolonged signaling through CD40. While CD40 ligation enhanced Fas-mediated apoptosis, stimulation with anti-IgM and IL-4 partially protected CD40L-activated B cells from Fas-mediated apoptosis. It was found that bcl-xL gene expression in normal splenic B cells was induced drastically by treatment with anti-IgM and IL-4, but not CD40L. By contrast, the expression of bcl-2 or bax was not significantly affected by these treatments. Moreover, in three of the four B lymphoma cell lines tested, Fas susceptibility correlated with the status of bcl-xL expression. The data suggest that an increase in bcl-xL expression may protect B cells from Fas-mediated apoptosis.

Serum levels of hyaluronic acid indicate the severity of joint symptoms in patients with systemic and polyarticular juvenile rheumatoid arthritis

OBJECTIVE

Elevated serum levels of hyaluronic acid (HA) correlate with joint inflammation in adult rheumatoid arthritis (RA). There are no laboratory indices for specifically assessing joint inflammation. Therefore, serial measurements of HA were assessed as a possible tool for measuring the severity of arthritic symptoms in children with juvenile rheumatoid arthritis (JRA).

METHODS

Serum levels of HA, measured by a sandwich assay method using HA binding protein, were correlated with the severity of joint symptoms and with laboratory test values in 71 patients with JRA, 30 children with other rheumatic diseases, and 138 children without rheumatic disease.

RESULTS

Serum levels of HA showed significant correlation with the severity of joint symptoms, but not with systemic symptoms, in patients with systemic and polyarticular JRA. No other laboratory tests, including C-reactive protein and erythrocyte sedimentation rate, reflected the severity of joint symptoms. This correlation of serum levels of HA with joint symptoms was observed in patients with systemic and polyarticular JRA, but not in pauciarticular JRA, other rheumatic diseases, or nonrheumatic diseases, even when signs of arthritis were present in the latter 3 groups.

CONCLUSION

Serum levels of HA are useful in objectively evaluating arthritic symptoms in patients with systemic and polyarticular JRA, and may have diagnostic value in this disease.

Contrast-enhanced MRI in spinal arteriovenous malformations and fistulae before and after embolisation therapy

MRI was performed in six cases of spinal arteriovenous malformation (AVM) and arteriovenous fistula (AVF) before and after embolisation. Intramedullary and perimedullary AVMs showed marked vascular enhancement after embolisation. This was thought to reflect feeding vessel occlusion and correlated well with a favourable clinical outcome. In dural AVFs, contrast-enhanced studies were essential for the diagnosis, unenhanced images being nonspecific. After embolisation, enhancement of the spinal cord was reduced, although one case with a poor outcome showed persistent enhancement.

Expression of hybrid isomyosins in human skeletal muscle

Myosin of human skeletal muscles was analyzed by means of several electrophoretic techniques. Myosin heavy chain (HC)-IIa-and HC-IIb-based isomyosins were identified by pyrophosphate-polyacrylamide gel electrophoresis (PP-PAGE). The electrophoretic mobilities of these fast-twitch muscle isomyosins differed in the order HC-IIa triplets < HC-IIb triplets. To determine the subunit composition of myosin molecules that function in intact muscle, two-dimensional electrophoresis in which the first and second dimensions were PP-PAGE and sodium dodecyl sulfate-PAGE, respectively, was also performed. Slow-twitch muscle isomyosin contained, in addition to slow-twitch light chain (LC) and HC-I isoforms, appreciable amounts of LC-2f, HC-IIa, and HC-IIb isoforms, and fast-twitch muscle isomyosin consisted of LC-2s and HC-I isoforms as well as fast-twitch LC and HC isoforms. Without consideration of HC- and slow-twitch alkali LC heterodimers, at least 31 possible isomyosins are derived from these findings on the subunit composition of isomyosins in human skeletal muscle.

Asymptomatic colorectal cancer detected by screening

PURPOSE

Colorectal cancer screening has become prevalent. To discuss the efficacy of screening, we studied the characteristic of asymptomatic colorectal cancer detected by screening.

METHODS

This is a retrospective review of patients with colorectal cancer treated at our institution. During the past 20 years, 96 of 1,046 cases of colorectal cancer were asymptomatic and detected by screening. Sixty-one of these cases were detected in the recent five years. The initial screening procedures were fecal occult blood test in 51 cases, sigmoidoscopy or colonoscopy in 18, barium enema in 9, and other tests in 18.

RESULTS

Thirteen lesions (14 percent) were smaller than 1.0 cm and 32 (33 percent) were 1-2 cm in size. There were 34 Tis, 21 T1, and 8 T2 tumors. Of the 55 Tis or T1 lesions, 14 showed nonpolypoid growth (5 flat-elevated, 7 flat-elevated with depression, 1 flat, 1 depressed), and 12 of these were detected on endoscopy. Thirty-four cases were TNM Stage 0, 25 were Stage I, 16 were Stage II, 12 were Stage III, and 9 were Stage IV. Sixty-one percent of those detected by screening were in either Stage 0 or Stage I compared with 16 percent in the symptomatic group. Cumulative five-year disease-free survival rates were 100 percent for both Stage 0 and Stage I, 94 percent for Stage II, and 52 percent for Stage III. Overall cumulative five-year survival rate was 87 percent for those detected by screening, compared with 57 percent in symptomatic patients.

CONCLUSIONS

Asymptomatic cancers detected by screening were at a less advanced stage. In particular, many nonpolypoid early cancers were detected by endoscopic screening.

Essential requirement of an invariant V alpha 14 T cell antigen receptor expression in the development of natural killer T cells

NK1.1+ T [natural killer (NK) T] cells express an invariant T cell antigen receptor alpha chain (TCR alpha) encoded by V alpha 14 and J alpha 281 segments in association with a limited number of V betas, predominantly V beta 8.2. Expression of the invariant V alpha 14/J alpha 281, but not V alpha 1, TCR in transgenic mice lacking endogenous TCR alpha expression blocks the development of conventional T alpha beta cells and leads to the preferential development of V alpha 14 NK T cells, suggesting a prerequisite role of invariant V alpha 14 TCR in NK T cell development. In V beta 8.2 but not B beta 3 transgenic mice, two NK T cells with different CD3 epsilon expressions, CD3 epsilon(dim) and CD3 epsilon(high), can be identified. CD3 epsilon(high) NK T cells express surface V alpha 14/V beta 8 TCR, indicating a mature cell type, whereas CD3 epsilon(dim) NK T cells express V beta 8 without V alpha 14 TCR and no significant CD3 epsilon expression (CD3 epsilon(dim)) on the cell surface. However, the latter are positive for recombination activating gene (RAG-1 and RAG-2) mRNA, which are only expressed in the precursor or immature T cell lineage, and also possess CD3 epsilon mRNA in their cytoplasm, suggesting that CD3 epsilon(dim) NK T cells are the precursor of V alpha 14 NK T cells.

Primary malignant lymphoma in the porta hepatis: a case report

A case of primary lymphoma in the porta hepatis is presented here. Cholangiography, angiography, ultrasonography and computed tomography suggested the presence of a mass in the porta hepatis, but all these failed to demonstrate the tumor clearly. Magnetic resonance imaging was very useful in defining the characteristics of the tumor and in delineating its extent, though it was not specifically diagnostic.

Intra-arterial digital subtraction angiography with extra-large fields using a computed radiography system in evaluating peripheral vascular disease

The authors evaluated the usefulness of intra-arterial digital subtraction angiography (DSA) with extra-large field sizes using a computed radiography (CR) system in evaluating peripheral vascular disease (PVD). Intra-arterial DSA using CR was performed in 55 patients with suspected PVD. A 4 F catheter was advanced into the abdominal aorta via the transbrachial approach and 90 ml of contrast medium was injected during six exposures using a long leg changer mounting a total of 18 imaging plates on six surfaces. Visualization of the superficial femoral and popliteal arteries was judged as diagnostic in all cases. The abdominal aorta, iliac arteries, and subtrifurcation were also visualized in most cases, but visualization was suboptimal in some cases. As a complication, median nerve palsy occurred in one case. This technique is thought to be a useful method for evaluating PVD because of the advantages of a large field of view and wide exposure latitude, in spite of its relatively long processing time.

Breast lesions: correlation of contrast medium enhancement patterns on MR images with histopathologic findings and tumor angiogenesis

PURPOSE

To compare qualitative and quantitative magnetic resonance (MR) mammographic features of breast lesions with histopathologic findings, especially tumor angiogenesis.

MATERIALS AND METHODS

Seventy-three patients (72 women, one man; aged 30-78 years; mean age, 51.0 years) with suspicious breast lesions underwent MR imaging. Noncontrast medium-enhanced localization imaging and then gadolinium-enhanced dynamic fast spoiled gradient-recalled-echo (SPGR) imaging were performed in all patients. In selected patients, subtraction fast SPGR images were obtained. The Pearson and Spearman correlation tests were used to determine the strength of the relationships between enhancement parameters and microvessel determinations.

RESULTS

Time intensity curve type correlated with microvessel density grade (Spearman rank correlation test: r = .90, P < .001). The steepest slope of contrast medium uptake correlated with microvessel counts (Pearson correlation test; r = .83, P < .001). Peripheral enhancement in invasive carcinomas (n = 9) correlated with high peripheral and low central microvessel densities, which were associated with desmoplasia and/or necrosis. Internal septations (n = 2) were seen only in fibroadenomas.

CONCLUSION

The density and distribution of microvessels may play major roles in the determination of the initial rate of contrast medium uptake and the heterogeneity of tumor enhancement.

Radiologically identifiable intratumoral portal vein in intrahepatic cholangiomas: a diagnostic pitfall

BACKGROUND

Although intratumoral patent portal vein (ITPV) is one of the characteristic features of benign hepatic lesions, ITPVs can be demonstrated in malignant tumors. We present the spectrum of MR and CT findings of ITPV identified in intrahepatic cholangiomas with pathological correlations.

METHODS

The ultrasound, CT and/or MRI findings of pathologically-confirmed intrahepatic cholangiomas were reviewed and correlated with surgical specimen or autopsy findings.

RESULTS

Intratumoral patent vessels were radiographically-demonstrated in 5 patients with intrahepatic cholangiomas. All intratumoral vessels were secondary or tertiary order portal vein branches. Some wall thickening was identified on pathological examinations.

CONCLUSION

The radiological demonstration of intratumoral portal vein is not a specific sign of benignity. In the case of a hepatic tumor with a patent portal tract, cholangioma should be considered, as well as benign tumors or lymphoma.

Helical CT imaging of bronchial arteries with curved reformation technique in comparison with selective bronchial arteriography: preliminary report

PURPOSE

Our goal was to evaluate the ability of helical CT to identify and demonstrate the origins and courses of bronchial arteries, using the curved reformation technique, in patients undergoing bronchial arterial interventional procedures.

METHODS

Thin section helical CT was performed on seven patients before bronchial arterial interventional procedures. The curved reformation technique was used to demonstrate the origins and continuous vessel tracing of bronchial arteries and compared with bronchial arteriographic findings.

RESULTS

In all, 16 bronchial arteries were evaluated, 8 on the right and 8 on the left. The origins of 12 bronchial arteries were identified. In the demonstration of tracing vessels, seven right bronchial arteries and three left were classified as excellent or fair.

CONCLUSION

Helical CT imaging with the curved reformation technique is helpful in identifying bronchial arteries, especially on the right, in patients with indications for bronchial arterial interventional procedures.

Adult human chondrocytes cultured in alginate form a matrix similar to native human articular cartilage

The matrix formed by adult human chondrocytes in alginate beads is composed of two compartments: a thin rim of cell-associated matrix that corresponds to the pericellular and territorial matrix of articular cartilage and a more abundant further-removed matrix, the equivalent of the interterritorial matrix in the tissue. On day 30 of culture, the relative and absolute volumes occupied by the cells and each of the two matrix compartments in the beads were nearly identical to those in native articular cartilage. Furthermore, the concentration of aggrecan in the cell-associated matrix was similar to that in adult human articular cartilage and was approximately 40-fold higher than in the further removed matrix compartment. Fluorescence-activated cell sorting revealed that the cell-associated matrix was built on the cell membrane in part via interactions between hyaluronic acid and CD44-like receptors. Approximately 25% of the aggrecan molecules synthesized by the chondrocytes during a 4-h pulse in the presence of [35S]sulfate on day 9 of culture were retained in the cell-associated matrix where they turned over with a half-life (t1/2) = 29 days. Most [35S]aggrecan molecules reached the further removed matrix compartment where they turned over much more slowly (t1/2 > 100 days). These results add support to the contention that aggrecan molecules residing in the pericellular and territorial areas of the adult human articular cartilage matrix are more susceptible to degradation by proteolytic enzymes synthesized by the chondrocytes than those that inhabit the interterritorial areas further removed from the cells.