Intraarticular administration of platelet-rich plasma with biodegradable gelatin hydrogel microspheres prevents osteoarthritis progression in the rabbit knee

OBJECTIVE

To investigate the therapeutic potential of administration of gelatin hydrogel microspheres containing platelet-rich plasma (PRP), by examining its effects on progression of osteoarthritis (OA) in a rabbit model.

METHODS

PRP and platelet-poor plasma (PPP) were prepared from rabbit blood. Adult rabbit chondrocytes were cultured in the alginate beads with the presence of 3% PRP or 3% PPP. Glycosaminoglycan (GAG) synthesis was quantified using dimethylmethylene blue assay. To confirm the anabolic effect of PRP in vivo, cartilage matrix gene expression was examined after intraarticular administration of PRP contained in gelatin hydrogel microspheres. The PRP contained in gelatin hydrogel microspheres was administered into the rabbit knee joint twice with an interval of 3 weeks, beginning 4 weeks after anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, gross morphological and histological examinations were performed.

RESULTS

PRP significantly stimulated chondrocyte GAG synthesis in vitro. In the knee joint, expression of proteoglycan core protein mRNA in the articular cartilage increased after administration of PRP contained in microspheres. Intraarticular injections of PRP in gelatin hydrogel microspheres significantly suppressed progression of OA in the ACLT rabbit model morphologically and histologically.

CONCLUSION

The present findings indicate that sustained release of growth factors contained in PRP has preventive effects against OA progression. These preventive effects appear to be due to stimulation of cartilage matrix metabolism, caused by the growth factors contained in PRP.

Perceived importance of being thin and smoking initiation among young girls

BACKGROUND

Smoking among adolescents remains unacceptably high and the difference in potential risk factors for smoking initiation between male and female adolescents has been explored. Although the association between smoking initiation and dieting behaviour has been observed among girls, the mechanism of the association is unknown.

OBJECTIVE

To examine prospectively the association between perceived importance of being thin at baseline and smoking initiation among girls.

DESIGN

A four year prospective cohort survey including perceived importance of being thin at baseline and smoking behaviour, conducted in 1993 and 1996.

SETTING AND PARTICIPANTS

273 Massachusetts female adolescents aged 12-15 years at baseline who reported having smoked no more than one cigarette by the time of the baseline survey, drawn from households sampled by random digit dialing.

MAIN OUTCOME MEASURE

Progression to established smoking, defined as having smoked 100 or more cigarettes in their lifetime.

RESULTS

After adjusting for age, smoking status at baseline, and race/ethnicity, girls who valued thinness most strongly and somewhat strongly were both more likely to have become established smokers, compared to the girls who valued thinness least strongly. The odds ratios are 4.5 (95% confidence interval (CI), 1.4 to 16.7) and 3.4 (95% CI 1.04 to 10.9), respectively.

CONCLUSIONS

The level of perceived importance of being thin among young female adolescents predicts future smoking initiation. Smoking prevention programmes designed for female adolescents may therefore benefit from the inclusion of content related to importance of being thin.

Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

BACKGROUND

To evaluate the changes of liver parenchymal enhancement in the cirrhotic liver by means of triple-phase dynamic magnetic resonance (MR) imaging.

METHODS

Triple-phase multisection dynamic MR imaging was performed in 32 patients with liver cirrhosis. The control group consisted of 19 patients without liver cirrhosis. After precontrast images were obtained, arterial phase images were acquired 20 s after the start of intravenous bolus administration of 0.10 mmol/kg of gadopentetate dimeglumine. Portal and delayed phase images were then acquired 1 and 3 min, respectively, after the injection of contrast material. On each phase image, the signal-to-noise ratio (S/N) from the liver parenchyma was measured by operator-defined regions of interest (ROIs). The contrast-enhanced ratio (CER) on each phase was then obtained according to the following formula: [S/N(arterial or portal or delayed phase image) - S/N(precontrast image)] / S/N(precontrast image). The portal perfusion index (PPI) also was obtained according to the following formula: [S/N(portal phase image - S/N(arterial phase image)] / S/N(arterial phase image). The results were expressed as mean +/- SD.

RESULTS

The CERs of arterial, portal, and delayed phase images in patients with and without liver cirrhosis were 0.256 +/- 0.211, 0.640 +/- 0.384, and 0.554 +/- 0.318 and 0.132 +/- 0.094, 0.404 +/- 0.204, and 0.324 +/- 0.144, respectively. The CERs were highest in the portal phase and lowest in the arterial phase in patients with and without liver cirrhosis. The CER of the cirrhotic liver was significantly higher than that of the normal liver in every phase (p < 0.05). PPIs with and without liver cirrhosis were 2.90 +/- 4.03 and 3.86 +/- 3.89, respectively. The PPI with liver cirrhosis was significantly lower than that without liver cirrhosis (p < 0.05).

CONCLUSION

The enhancement of cirrhotic liver parenchyma is greater than that of the normal liver parenchyma at every phase of triple-phase dynamic MR imaging.

Four subunit a isoforms of Caenorhabditis elegans vacuolar H+-ATPase. Cell-specific expression during development

We have identified four genes (vha-5, vha-6, vha-7, and unc-32) coding for vacuolar-type proton-translocating ATPase (V-ATPase) subunit a in Caenorhabditis elegans, the first example of four distinct isoforms in eukaryotes. Their products had nine putative transmembrane regions, exhibited 43-60% identity and 62-84% similarity with the bovine subunit a1 isoform, and retained 11 amino acid residues essential for yeast V-ATPase activity (Leng, X. H., Manolson, M. F., and Forgac, M. (1998) J. Biol. Chem. 273, 6717-6723). The similarities, together with the results of immunoprecipitation, suggest that these isoforms are components of V-ATPase. Transgenic and immunofluorescence analyses revealed that these genes were strongly expressed in distinct cells; vha-5 was strongly expressed in an H-shaped excretory cell, vha-6 was strongly expressed in intestine, vha-7 was strongly expressed in hypodermis, and unc-32 was strongly expressed in nerve cells. Furthermore, the vha-7 and unc-32 genes were also expressed in the uteri of hermaphrodites. RNA interference analysis showed that the double-stranded RNA for unc-32 caused embryonic lethality similar to that seen with other subunit genes (vha-1, vha-4, and vha-11) (Oka, T., and Futai, M. (2000) J. Biol. Chem. 275, 29556-29561). The progenies of worms injected with the vha-5 or vha-6 double-stranded RNA became died at a specific larval stage, whereas the vha-7 double-stranded RNA showed no effect on development. These results suggest that V-ATPases with these isoforms generate acidic compartments essential for worm development in a cell-specific manner.

Sequence heterogeneity of the ten rRNA operons in Clostridium perfringens

We have cloned and sequenced rRNA operons of Clostridium perfringens strain 13 and analyzed the sequence structure in view of the phylogenesis. The organism had ten copies of rRNA operons all of that comprised of 16S, 23S and 5S rDNAs except for one operon. The operons clustered around the origin of replication, ranging within one-third of the whole genome sequence as it is arranged in a circle. Seven operons were transcribed in clockwise direction, and the remaining three were transcribed in counter clockwise direction assuming that the gyrA was transcribed in clockwise direction. Two of the counter clockwise operons contained tRNA(Ile) genes between the 16S and 23S rDNAs, and the other had a tRNA(Ile) genes between the 16S and 23S rDNAs and a tRNA(Asn) gene in the place of the 5S rDNA. Microheterogeneity was found within the rRNA structural genes and spacer regions. The length of each 16S, 23S and 5S rDNA were almost identical among the ten operons, however, the intergenic spacer region of 16S-23S and 23S-5S were variable in the length depending on loci of the rRNA operons on the chromosome. Nucleotide sequences of the helix 19, helix 19a, helix 20 and helix 21 of 23S rDNA were divergent and the diversity appeared to be correlated with the loci of the rRNA operons on the chromosome.

Inferior phrenic arteries: depiction with thin-section three-dimensional contrast-enhanced dynamic MR imaging with fat suppression

The purpose of this study was to evaluate visibility of the inferior phrenic arteries in normal subjects at thin-section, multiphasic, three-dimensional (3D) contrast-enhanced dynamic magnetic resonance (MR) imaging with fat suppression, and to compare the appearances and frequencies of MR visualization of these vessels between normal and cirrhotic patients. This study included 95 patients (44 normal and 51 cirrhotic patients) who underwent 3D contrast-enhanced dynamic imaging on a high-performance gradient (25 mT/m) system as a part of abdominal MR examinations. The right and left inferior phrenic arteries were visible in 84% and 73% of the normal subjects, respectively. The averaged rating for visibility in the right inferior phrenic artery was significantly greater in the cirrhotic patients than in the normal subjects (2.1 +/- 0.1 vs. 1.7 +/- 0.2; P = 0.040). Mean diameters of the right inferior phrenic artery in the cirrhotic patients (1.7 +/- 0.1 mm) were significantly larger (P = 0.002) than those in the normal subjects (1.3 +/- 0.1 mm). No significant difference was noted in the mean diameters and the visibility of the left inferior phrenic artery between the two groups. The inferior phrenic arteries can frequently be identified on thin-section, 3D contrast-enhanced arterial-phase dynamic MR images with fat-suppression techniques. Dilatation of the right inferior phrenic artery depicted by this technique may be a nonspecific but an additional secondary finding suggestive of cirrhosis.

Heterogeneity of T cell clones specific for a single indirect alloantigenic epitope (I-Ab/H-2Kd54-68) that mediate transplant rejection

BACKGROUND

One of the complexities of solid organ allograft rejection is the inherent diversity of the specific T cell antigenic epitopes that participate in this response, including the role of direct alloantigen recognition and indirect recognition of donor-derived peptides in recipient antigen-presenting cells. To probe the role of distinct T cell receptor (TCR) avidity differences and the role of cytokine expression patterns of different effector T cells that may participate in allograft rejections, we have identified a dominant allopeptide derived from the H-2Kd molecule, recognized by H-2b CD4 T cells in the context of syngeneic I-Ab.

METHODS

To identify a stimulatory peptide derived from the H-2Kd molecule, a panel of synthetic overlapping peptides was screened for immunogenicity and a panel of T cell clones established. These clones were characterized for TCR Vbeta usage by mAb staining and/or reverse transcribed-polymerase chain reaction analysis, peptide dose sensitivity as a marker of TCR avidity, cytokine expression phenotype in vitro, and their ability to mediate rejection of a vascularized cardiac allograft after adoptive transfer to immunodeficient mice.

RESULTS

The H-2Kd54-68 peptide was identified as a dominant stimulatory peptide by the ability of T cells from C57BL/6 (H-2b) mice primed by a combination of allogeneic spleen cell injection and mixed peptide immunization to mount an in vitro proliferative response and interferon-gamma production by peptide stimulation. Furthermore, direct immunization with synthetic H-2Kd54-68 peptide of normal C57BL/6 mice resulted in accelerated rejection of both skin and cardiac allografts from B10.D2 (H-2d) mice, but not 3rd party B10.BR (H-2k) grafts. A panel of 15 distinct CD4+ clones specific for H-2Kd54-68 peptide were established and shown to utilize a variety of TCR Vbeta and different apparent TCR avidities to H-2Kd54-68 peptide when stimulated in vitro. To characterize these clones further, two clones were chosen based on the difference of avidity to H-2Kd54-68 peptide. The cytokine expression pattern was determined and indirect alloantigen specificity confirmed by analysis of responses to purified peptide and B10.D2 spleen cells using normal H.2b and I-Abeta chain knockout mice as APC donors. Both of these T cell clones were able to mediate rejection of B10.D2, but not B10.BR hearts, in immunodeficient mice, but the morphological pattern of T cell infiltration was distinct.

CONCLUSIONS

These results demonstrate the potential importance of fine dissection of the alloantigeneic response to solid organ transplants and provide unique insights into the role of TCR avidity and cytokine expression patterns in different morphological patterns of transplant rejection.

Effects of market liberalisation on smoking in Japan

OBJECTIVE

To document the effect of the liberalisation of the Japanese tobacco market on Japanese smoking rates and on Japanese tobacco industry practices.

DATA SOURCE

Asahi Shimbun (major daily newspaper) from 1980 to 1996.

STUDY SELECTION

Review of media coverage on the effects of market liberalisation following the imposition of the USA's section 301 trade sanction.

DATA SYNTHESIS

The opening of Japan's tobacco market to foreign cigarette companies stalled a decline in smoking prevalence. Smoking rates among young women increased significantly, and also appear to be on the rise among adolescents. Aggressive marketing and promotional activities by US and Japanese tobacco companies in response to trade liberalisation appear responsible for these adverse trends. Steep increases in sales through vending machines were also possible contributors to the rising smoking prevalence among adolescents. On the positive side, market liberalisation indirectly promoted smoking control efforts in Japan, by causing an anti-smoking movement to coalesce.

CONCLUSION

Market liberalisation in Japan played a significant role in increasing smoking prevalence among young women and adolescents while helping to transform the issue of smoking in Japan from a matter of individual choice to a public health problem.

Foreign serum-induced bile duct lesion (BDL) in athymic BALB/c nude mice

To investigate a role of cellular immunity in foreign serum-induced bile duct lesion (BDL) in mice, athymic BALB/c nude (nu/nu) mice were intraperitoneally injected with swine serum (SS) twice a week up to 8 weeks and were compared with euthymic BALB/c heterozygote (nu/+) and wild-type (+/+) mice treated with SS in the same way for 4 weeks. All immunized nu/+ and +/+ mice developed marked BDL, and their sera showed high anti-SS IgE and IgG1 antibody titers, whereas no immunized nu/nu mice developed lesions, and their sera showed no elevation of antibody titers. Next, nu/nu mice were reconstituted with splenocytes derived from nu/+ mice, and then were intraperitoneally injected with SS twice a week for 3 weeks. Most of the reconstituted nu/nu mice developed BDL, and their sera showed the elevation of anti-SS IgE and IgG antibody titers. These results suggest that cellular immunity may play a pivotal role in the pathogenesis of swine serum-induced BDL.

Immunopathological study on the development of swine serum-induced bile duct lesions in BALB/c and DBA/2 mice

To compare the difference in the development of swine serum (SS)-induced bile duct lesion (BDL) between high responder BALB/c and low responder DBA/2 mice, the mice of both strains injected with SS twice a week for up to 4 weeks were killed and examined immunopathologically after the 2nd, 4th, 6th and 8th SS-injection, respectively. In BALB/c mice, BDL developed rapidly following the SS-injections, and a slight enlargement of common bile ducts accompanied with infiltration of T helper cells and eosinophils was detected after the 2nd SS-injection. From the 4th injection on, BDL was characterized by proliferation of mucous glands, hyperplasia and hypertrophy of biliary and glandular epithelial cells, periductal fibrosis, infiltration of eosinophils, plasma cells and T helper cells, and increase of mast cells, resulting in more apparent enlargement of common bile ducts. Several hypertrophied biliary and glandular epithelial cells were positive for mouse immunoglobulins and SS. BDL subsided after cessation of the SS-treatment. On the other hand, in DBA/2 mice, immune response and inflammatory reaction were very weak, and only slight BDL were detected.

Oddi sphincter and common channel: evaluation with pharmacodynamic MR cholangiopancreatography using fatty meal and secretin stimulation

PURPOSE

This study was performed to assess the usefulness of pharmacodynamic MR cholangiopancreatography (MRCP) in depicting the segment covered by the Oddi sphincter.

MATERIALS AND METHODS

Twelve volunteers were studied by pharmacodynamic MRCP. After stimulation by the oral intake of a fatty meal and an intravenous injection of secretin, a single-shot rapid acquisition relaxation enhancement (RARE) sequence was used to obtain consecutive images of the segment covered by the Oddi sphincter. The contraction range of the Oddi sphincter and the lengths of the common channel were measured on the MR console by comparing the most contracted image of the sphincter with the most relaxed image.

RESULTS

Pharmacodynamic MRCP showed periodic contraction of the Oddi sphincter in all cases. The range of sphincteric contraction over the biliary duct was 8-19 mm (11.8+/-3.2 mm, mean +/- standard deviation) and over the pancreatic duct 8-23 mm (10.0+/-1.5 mm). In 11 of the 12 cases, the common channel was depicted and its length ranged from 3-8 mm (5.2+/-1.3 mm).

CONCLUSION

Pharmacodynamic MRCP clearly depicted the range of contraction of the Oddi sphincter and the common channel, which are not usually revealed by conventional MRCP.

A preliminary study of discrimination among the components of small pulmonary nodules by MR imaging: correlation between MR images and histologic appearance

PURPOSE

To investigate whether magnetic resonance (MR) imaging depicts the internal characteristics of small pulmonary nodules.

METHODS

We reviewed MR images of 39 surgically resected pulmonary nodules 3 cm or less and compared the components within the nodules. In 22 malignant nodules, eight histologic components were characterized by signal and enhancement patterns on MR images.

RESULTS

MR images obtained from any single sequence discriminated all components in 26 (67%) nodules, whereas the combination of images from various sequences allowed discrimination in 35 (90%). Fourteen of 16 components of aggregated tumor cells showed marked early enhancement. Although fibrotic and necrotic components showed no or slight early enhancement, nine of 10 fibrotic components showed hypointensity and six of seven necrotic components showed hyperintensity on T2-weighted images. Component characterization in eight histologies by MR imaging was possible in 71-100%.

CONCLUSION

Our study demonstrated that MR imaging offers the possibility of high tissue-contrast resolution in small pulmonary nodules.

[Outpatient chemotherapy with infusional 5-fluorouracil in advanced gastrointestinal cancer]

These studies were designed to evaluate the efficacy, toxicity, and resulting quality of life (QOL) of outpatient chemotherapy with infusional 5-FU for advanced gastrointestinal cancer. Schedule, sch. A: Treatment consisted of CI 5-FU 200 mg/m2/day, days 1-28, IVB Leucovorin 20 mg/m2 q week. Fifteen patients with advanced gastrointestinal cancer were treated to maintain the efficacy of prior inpatient chemotherapy. Twenty-one patients treated with adjuvant chemotherapy were added to evaluate toxicity and QOL. The mean time to progression (TTP) was 2.6 months. Grade 2 toxicities were seen, including mucositis (23%) and diarrhea (7%). Hand-foot syndrome was seen 60% of patients. The mean QOL score was 89.5 +/- 7.8. Sch.B: Treatment consisted of weekly 24 h infusion of 5-FU 2,600 mg/m2. 5-FU was administered using a Groshong catheter and Baxter infusor LV5 (5 ml/hr). Nine patients with advanced gastrointestinal cancer were treated. Twenty-one patients were treated with adjuvant chemotherapy. The mean TTP was 3.6 month. Grade 2 toxicities were seen, including leucocytopenia (7%), mucositis (3%), diarrhea (10%), and nausea and vomiting (10%). The mean QOL score was 82.6 +/- 10.7. In conclusion, both 5-FU schedules are feasible for outpatient chemotherapy for advanced gastrointestinal cancer.

Process of carboxylation of glutamic acid residues in the gla domain of human des-gamma-carboxyprothrombin

In the absence of vitamin K (VK) or in the presence of VK antagonists, hepatic VK-dependent carboxylase activity is inhibited and des-gamma-carboxyprothrombin (DCP) is released into the blood. We analyzed the number of glutamic acid (Glu) residues and their positions in the Gla domain (GD) of DCP to investigate the gamma-carboxylation mechanism of VK-dependent carboxylase. Several DCPs were found in each subject studied. The 10 Gla residues of human prothrombin were carboxylated in order from the N-terminal (residues 26, 25, 16, 29, 20, 19, 14, 32, 7 and 6). The process of Glu carboxylation seemed to proceed three-dimensionally from inside to outside the molecule.

Viral-induced cirrhosis: grading of severity using MR imaging

OBJECTIVE

The purpose of this study was to determine whether MR imaging can be used to grade the severity of cirrhosis.

MATERIALS AND METHODS

The MR examinations of 46 patients with cirrhosis were retrospectively reviewed independently by two radiologists and correlated with clinical severity assessed by Child-Pugh classification. MR imaging analysis by reviewers who were unaware of clinical status included comparison of volume indexes (computed as the product of three axis measurements) of the spleen and each segment of the liver, and changes in hepatic contour, iron or fat deposition, and presence of varices and collaterals.

RESULTS

Volume index of the spleen and the presence of ascites and varices were significantly and positively correlated (p = .008, .002, .0001, respectively) with the clinical severity of cirrhosis (Child-Pugh classifications), and volume indexes of the posterior, medial, and lateral segments of the liver were significantly and inversely correlated (p = .001, .049, .041, respectively). On an MR scoring system based on four items (volume index of the spleen; volume index of posterior + medial + lateral segments; presence of ascites; and presence of varices and collaterals), averaged total MR scores were 2.5 +/- 0.3, 4.9 +/- 0.6, and 7.9 +/- 0.8 for Child-Pugh grades A, B, and C, respectively (p < .0001). The accuracy of MR scoring in distinguishing between clinical Child-Pugh grade A cirrhosis and further grades was 89%, the sensitivity was 93%, and the specificity was 82%.

CONCLUSION

An MR scoring system can be used to grade the severity of cirrhosis.

Hepatocellular carcinoma: association with increased iron deposition in the cirrhotic liver at MR imaging

PURPOSE

To determine whether the frequency of hepatocellular carcinoma (HCC) in patients with cirrhosis is affected by hepatic iron deposition as detected with magnetic resonance (MR) imaging.

MATERIALS AND METHODS

In a retrospective search of MR imaging and histopathology records, 196 patients with histopathologically proved cirrhosis and with (n = 80) or without (n = 116) HCC who underwent T2-weighted conventional or fast spin-echo and gradient-echo (GRE) (echo time > or = 6.0 msec) imaging were identified. MR images were qualitatively and quantitatively evaluated for diffuse hepatic iron deposition and siderotic regenerative nodules to assess their correlation with the presence of HCC.

RESULTS

Hepatic parenchymal iron deposition was seen in 79 (40%) patients, and iron deposition in regenerative nodules was seen in 71 (36%) at MR imaging. The mean signal intensity ratio of GRE images in patients with hepatic iron deposition was significantly lower than that in patients without it (P < .001). The frequency of HCC in patients with iron deposition in regenerative nodules (52% [37 of 71 patients]) was significantly higher (P = .015) than that in patients without iron in regenerative nodules (34% [43 of 125 patients]).

CONCLUSION

The occurrence of HCC may be associated causally with iron deposition in regenerative nodules in patients with cirrhosis. MR imaging can enable detection of iron deposition in regenerative nodules as a possible risk factor for the development of HCC.

Hepatic perfusion abnormalities in acute pancreatitis: CT appearance and clinical importance

BACKGROUND

The purpose of the present study was to describe the computed tomography (CT) appearances of transient hepatic attenuation differences (THADs) in patients with acute pancreatitis and to discuss the mechanism of THAD.

METHODS

Two-phase dynamic CT images of 28 patients with acute pancreatitis were reviewed. Among them, THAD was seen in nine patients. All patients underwent ultrasonography, and four patients with THAD underwent surgery.

RESULTS

Three types of THAD (THAD adjacent to the gallbladder in five of 28 patients, THAD with left lobar distribution in three of 28, wedge-shaped THAD in one of 28) were seen on the two-phase dynamic CT scans of patients with acute pancreatitis. In five patients, THAD disappeared when acute pancreatitis had subsided.

CONCLUSIONS

THAD in acute pancreatitis is probably caused by increased arterial blood flow attributable to the inflamed lobe of the liver or the inflamed gallbladder. THAD in acute pancreatitis should not be confused with primary liver abnormalities.

The evidence for tonic GABAergic regulation of basal L-DOPA release via activation of inhibitory GABA(A) receptors in the nucleus tractus solitarii of anesthetized rats

We have proposed that DOPA is a neurotransmitter of the primary baroreceptor afferents terminating in the rat nucleus tractus solitarii (NTS). GABA is a putative inhibitory neuromodulator for baroreflex inputs in the NTS. Thus, GABA may inhibit DOPAergic transmission in the NTS. We tried to clarify whether basal DOPA release is inhibited by muscimol, a GABA(A) agonist, and facilitated by bicuculline, a GABA(A) antagonist, during microdialysis of the NTS in anesthetized rats. DOPA release was consistently detectable. Muscimol 10-100 microM perfused via probes gradually inhibited concentration-dependently DOPA release. Peak 30% inhibition occurred 2 h after perfusion. Muscimol (30 microM)-induced inhibition was antagonized by non-effective 10 microM bicuculline. Bicuculline (30 microM) elicited peak 30% facilitation of DOPA release 2 h after perfusion. Endogenous GABA seems to regulate tonically basal DOPA release via activation of inhibitory GABA(A) receptors in the rat NTS. These findings further support the above proposal.

GABA may function tonically via GABA(A) receptors to inhibit hypotension and bradycardia by L-DOPA microinjected into depressor sites of the nucleus tractus solitarii in anesthetized rats

We have proposed that DOPA is a transmitter of the primary baroreceptor afferents terminating in the rat nucleus tractus solitarii (NTS). GABA is a putative inhibitory neuromodulator for baroreflex inputs in the NTS. GABA may inhibit DOPAergic transmission. Drugs were microinjected into depressor sites of the NTS in anesthetized rats. DOPA (10-60 ng) elicited dose-dependent depressor responses. GABA (3-300 ng) elicited dose-dependent pressor responses. Nipecotic acid (100 ng) elicited pressor responses. Bicuculline (10 ng) elicited depressor responses. Responses to DOPA (30 ng) were inhibited by pretreatment with GABA and nipecotic acid, but potentiated by bicuculline, when vascular responses to pretreated drugs returned to basal levels. DOPA ME, a competitive DOPA antagonist, did not displace specific [3H]GABA binding. Prior DOPA ME (1 microg) inhibited by one-half pressor responses to 300 ng GABA. GABA seems to inhibit tonically via GABA(A) receptors depressor responses to DOPA and to elicit pressor responses partially by inhibition of tonic function of endogenous DOPA to activate depressor sites in the NTS. These findings further support the above proposal.

Detection of hepatocellular carcinoma: comparison of T2-weighted breath-hold fast spin-echo sequences and high-resolution dynamic MR imaging with a phased-array body coil

The purpose of our study was to compare T2-weighted breath-hold fast spin-echo sequence (BHFSE) and high-resolution dynamic MR imaging (HR-DMRI) in the detection of hepatocellular carcinoma (HCC). Short and long T2-weighted BHFSE sequences and biphasic HR-DMRI including arterial-dominant and delayed phase images with a phased-array body coil were performed in 30 consecutive patients with 37 HCCs. The lesion-to-liver contrast-to-noise ratio (CNR) was quantitatively measured. The lesion conspicuity and delineation was qualitatively rated according to a four-point scale. The lesion-to-liver CNR was highest with the arterial-dominant phase HR-DMRI and was significantly higher than those obtained with both short and long T2-weighted BHFSE and those obtained with unenhanced and delayed HR-DMRI. The CNR obtained with short T2-weighted BHFSE was significantly higher than those obtained with long T2-weighted BHFSE and with unenhanced and delayed HR-DMRI. The sensitivity for the sequences was 78.4% (29/37) for short T2-weighted BHFSE, 67.6% (25/37) for long T2-weighted BHFSE, 37.8% (14/37) for unenhanced HR-DMRI, 97.3% (36/37) for arterial-dominant phase HR-DMRI, and 43.2% (16/37) for delayed HR-DMRI. The sensitivity of serial dynamic MR imaging combined with unenhanced, arterial-dominant phase imaging and delayed phase imaging was 100% (37/37). The score in the qualitative analysis of the lesion conspicuity and delineation was highest for the arterial-dominant phase HR-DMRI and was significantly higher than that for the short T2-weighted BHFSE. The score for the short T2-weighted BHFSE was significantly higher than that for the long T2-weighted BHFSE and that for the unenhanced HR-DMRI. Arterial-dominant phase HR-DMRI is superior to the T2-weighted BHFSE technique, and also HR-DMRI combined with unenhanced, arterial-dominant and delayed phases is the most sensitive technique in the detection of HCC.

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

BACKGROUND

T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy.

METHODS

MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations.

RESULTS

Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2-9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas.

CONCLUSION

The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy.

[Outpatient chemotherapy with weekly high-dose infusional 5-fluorouracil (weekly HD-FU) in advanced gastrointestinal cancer]

This study was designed to evaluate the efficacy, toxicity, and quality of life (QOL) of outpatient chemotherapy with weekly HD-FU in advanced gastrointestinal cancer. Treatment consisted of weekly 24-h infusion of 5-FU 2,600 mg/m2, 5-FU was administered using the Groshong catheter and the Baxter infusor LV 5 (5 ml/hr). Eight patients (pts) with advanced gastrointestinal cancer were treated 64 times (mean 8.0 times), and 21 pts were treated 168 times (mean 8.0 times) with adjuvant chemotherapy. Grade 3 or 4 toxicities were not observed. Catheter occlusions and balloon rupture were observed in 1 case each. Responses were PR 2 and NC 6. Mean times to progression were 2.0 and 3.5 months, respectively. Mean scores of QOL were: 70.5 +/- 8.2 before treatment, 78.0 +/- 13.0 after 3 weeks, 79.8 +/- 7.9 after 5 weeks, and 75.8 +/- 11.3 after treatment completion. In adjuvant cases, these scores were 80.6 +/- 11.4, 83.1 +/- 10.7, 85.1 +/- 11.5, and 91.8 +/- 6.9, respectively. In conclusion, a schedule of 5-FU is feasible for outpatient chemotherapy in advanced gastrointestinal cancer.

[Comparative studies of breath-hold magnetic resonance cholangiopancreatography (MRCP) between different two sequences and between 1.0T and 1.5T units]

In this article, a comparative study in the diagnostic ability of a breath-hold MRCP between thin slice half-Fourier acquisition single-shot turbo spin-echo (HASTE) and thick slice rapid acquisition with relaxation enhancement (RARE), and between 1.5T and 1.0T units was made. Although thin slice HASTE sequence might be more excellent in the diagnostic ability than thick slice RARE, the ability of depiction of pancreaticobiliary system on MRCP was not statistically different between these two sequences and between 1.0T and 1.5T units. Thick slice RARE sequence was inferior to thin slice HASTE in the depiction of gallbladder stone. However, thick slice RARE sequence was useful for MRCP because a projection image of pancreaticobiliary system could be easily obtained without postprocessing and without misregistration. Thick slice RARE sequence should be used in combination with thin slice HASTE sequence for the diagnosis of pancreaticobiliary system.