Vascular endothelial growth factor and platelet-derived growth factor are potential angiogenic and metastatic factors in human breast cancer

BACKGROUND

Angiogenesis is a prerequisite for tumor growth and metastasis. Tumor angiogenesis may be mediated by several angiogenic factors such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), transforming growth factor-alpha, and basic fibroblast growth factor.

METHODS

Differential mRNA expressions of VEGF, PDGF (A chain), transforming growth factor-alpha and basic fibroblast growth factor in 32 primary invasive breast tumors were examined by reverse transcriptase-polymerase chain reaction. We analyzed relationships between mRNA expressions of these angiogenic factors and the degree of angiogenesis, tumor size, and metastasis. Quantification of angiogenesis was achieved by the immunohistochemical staining of endothelial cells with antibody to CD31.

RESULTS

VEGF and PDGF-A mRNAs were expressed more frequently in breast tumors than in nontumor breast tissues, whereas no difference was found in expression frequency of either transforming growth factor-alpha or basic fibroblast growth factor mRNA. Vascular counts in tumors correlated with each expression frequency of VEGF and PDGF-A mRNA. PDGF-A mRNA was expressed more frequently in tumors with lymph node metastasis than in those without metastasis.

CONCLUSIONS

Expression of VEGF and PDGF mRNAs detected by reverse transcriptase-polymerase chain reaction in breast tumors correlates with tumor-related characteristics of angiogenesis and metastatic potential. Analysis of these mRNAs by reverse transcriptase-polymerase chain reaction may be useful for assessing the biologic behavior of a breast tumor before surgical treatment.

Purification of a marine bacterial glucose dehydrogenase from Cytophaga marinoflava and its application for measurement of 1,5-anhydro-D-glucitol

A novel glucose dehydrogenase (GDH) from a marine bacterium Cytophaga marinoflava IFO 14170 was isolated from its membrane fraction. This GDH catalyzes the oxidation of a hydroxy group of glucose, but does not react in its C-1 position. This enzyme is composed of a single peptide with a mol wt of 67,000. The GDH can react under high salinity. The optimum pH is around 8.0, showing typical property of marine bacterial enzymes. Using this novel enzyme, and enzymatic determination of 1,5-anhydro-D-glucitol (1,5AG) utilizing 2,6-dichrolophenolindophenol (DCIP) and phenazine methosulfate (PMS) as electron mediators was carried out. A good linear correlation was observed from 0.5 mM to 4 mM of 1,5AG.

Elevated amylase is related to the development of respiratory failure in organophosphate poisoning

1. A retrospective study of organophosphate (OP) poisoning in the intensive care unit was performed to analyze the incidence of respiratory failure. 2. The patients were treated initially with gastrointestinal decontamination including gastric lavage and the administration of activated charcoal with cathartic. Further management included intravenous pralidoxim and atropine and ventilatory support. 3. Of the 32 OP poisoning patients, 16 patients developed respiratory failure and received ventilatory support. 4. An increase in plasma amylase above the normal range on the day of admission was related to the development of respiratory failure. 5. In OP poisoning, the elevation of amylase level was predictive of the subsequent respiratory failure.

Transcatheter Inoue endovascular graft for treatment of canine aortic dissection

We examined whether the Inoue endovascular graft could be used as a device for the treatment of aortic dissection. This graft consists of a cylinder made from a thin Dacron sheet suspended by several extra-flexible wire rings. Aortic dissections were experimentally created in 11 dogs. Using aortography and intravascular ultrasound imaging (IVUS), we selected the size of the graft diameter according to the diameter of the normal descending aorta (distal to aortic dissection) in 5 dogs (group I) and according to the diameter of the true lumen of the aorta within the aneurysm in 6 dogs (group II). The graft was deployed transfemorally through a 15-F long sheath into the aneurysm to close the entry site, immediately after creation of the aortic dissection. The entry was completely closed in all dogs after immediate implantation. All 5 dogs in group I died within 11 days (mean, 7 days) after graft deployment. However, all grafts in group II were tolerated very well and followed up for as long as 5 months. After the follow up, IVUS and aortography showed no rupture of the aortic aneurysmal wall and no migration, leakage, or damage to the graft in any of the 6 dogs. These 6 dogs were sacrificed and autopsy showed that the graft was covered by a thin, translucent, neointima, effectively recreating a new aortic lumen and completely closing the entry of the aneurysm. The Inoue endovascular graft proved to be effective in the long-term treatment of aortic dissection without surgery, when the size of the graft was selected according to the diameter of the true lumen of the aorta within the aneurysm.

Comparison of routine and selective endoscopic retrograde cholangiography before laparoscopic cholecystectomy

To evaluate the role of endoscopic retrograde cholangiography (ERC) before laparoscopic cholecystectomy, we compared the frequency of concomitant common bile duct stones, their clinical outcome, and the frequency of bile duct injury between a group of 128 patients with routine preoperative ERC (group A) and 1010 patients with selective ERC (group B). Overall, 48 patients (4.2%) had duct stones, but the predictive signs were absent in six of them (12.5%). The stones were demonstrated by ERC and removed by sphincterotomy in all 11 patients in group A. Of 37 patients in group B, 22 were diagnosed by selective ERC and underwent endoscopic removal. Of four patients whose stones were found by operative cholangiography, one had immediate open surgery, another passed a stone spontaneously, and the other two underwent postoperative sphincterotomy, which failed in one. The stones were not recognized until pain recurred in the remaining 11 patients. Sphincterotomy was successful in nine patients but failed in the other two. Thus postoperative sphincterotomy failed in 3 of 13 patients (23%), necessitating open surgery. Forty-two patients overall (3.7%) had aberrant biliary tract anatomy, which did not lead to bile duct injury in any of the patients. Morbidity of routine ERC (3.1%) was lower than that of selective ERC (7.4%) (p < 0.05). It should be noted that a certain proportion of duct stones may be missed by selective ERC, necessitating laparotomy when sphincterotomy fails. The routine use of preoperative ERC may be justified at institutions where the expertise is available, at least until laparoscopic lithotomy becomes easy.

Angiotensin II-dependent down-regulation of vascular natriuretic peptide type C receptor gene expression in hypertensive rats

Biological actions of natriuretic peptide (NP) are determined by the condition of the receptor as well as that of the hormone. Although we previously demonstrated in hypertensive rats the up-regulation of NP-A receptor that mediates various biological actions of NPs, the pathophysiologic significance of NP-C receptor, another subtype thought to be related to clearance of NPs and possibly to biological actions, remains unknown. In the present study, we determined NP-C receptor messenger RNA (mRNA) level in the aortic tissue of stroke-prone spontaneously hypertensive rats (SHR-SP/Izm) and in cultured aortic smooth muscle cells by ribonuclease protection assay. The aortic NP-C receptor mRNA level in SHR-SP/Izm was significantly lower than that in the control WKY/Izm. Oral administration of an angiotensin (Ang) II receptor (AT1) antagonist, TCV-116, but not a calcium channel blocker, manidipine, reversed the down-regulated NP-C receptor mRNA in SHR-SP/Izm to the level in WKY/Izm, whereas the latter was more potent in decreasing the blood pressure. In cultured aortic smooth muscle cells, the NP-C receptor was the predominant subtype. Ang II decreased the NP-C receptor mRNA level in a dose-dependent manner, but this effect was reversed by an AT1 antagonist, CV-11974. Neither the NP-A nor NP-B receptor mRNA level was altered by Ang II. These findings indicate that vascular NP-C receptor is down- regulated via Ang-II-mediated mechanism in SHR-SP/Izm. The phenomenon, together with the up-regulation of the NP-A receptor, may play an important role in counteracting hypertension by enhancing the action of NPs.

Indications for and limitations of extended cholecystectomy in the treatment of carcinoma of the gall bladder

OBJECTIVE

To assess the indications for, and limitations of, extended cholecystectomy in the treatment of carcinoma of the gall bladder. DESIGN. Retrospective study.

SETTING

University hospital, Japan.

SUBJECTS

23 Patients who were operated on for carcinoma of the gall bladder, 1982-92 out of the total of 73 who presented to our department with the disease.

INTERVENTIONS

Extended cholecystectomy with en bloc lymph node dissection with or without resection of the extrahepatic bile duct, or hepatic resection, or pancreaticoduodenectomy, or a combination.

MAIN OUTCOME MEASURES

Outcome related to TNM classification.

RESULTS

7 Patients had stage I or II disease, and their cumulative five year survival rates (including one censored death) were 67% and 100%, respectively; 9 patients had stage III disease and of these 2/4 patients with T3N1 tumours died of their cancer, but the remaining 7 were alive a mean of 58 months later (though there was one censored death). Of the 7 with stage IV disease all but one were dead within 16 months despite more extensive surgery. The cumulative five year survival was 92% in patients with stage I, II and III (except T3N1 tumours).

CONCLUSION

Extended cholecystectomy with or without resection of the extrahepatic bile duct is indicated for patients with stage I, II, or III (except T3N1) tumours of the gall bladder.

Effect of neonatal exposure to diethylstilbestrol and tamoxifen on pelvis and femur in male mice

BACKGROUND

Permanent abnormalities have been reported in reproductive and non-reproductive organs of mice and humans exposed perinatally to a synthetic estrogen, diethylstilbestrol (DES). Recent studies demonstrated that sex hormones affected the shape of the innominate bone in mice. Therefore, we analyzed the long-term effects of neonatal exposure of DES and tamoxifen, an anti-estrogen, in mouse bones.

METHODS

Changes in the pelvis and femur were examined in 1- to 15-month-old C57BL/Tw male mice given 5 daily injections of 3 micrograms DES or of 100 micrograms tamoxifen beginning on the day of birth by measuring contents of calcium (Ca) and phosphorus (P), and the numbers of osteoblasts and osteoclasts.

RESULTS

The ash weight of pelvis and femur in neonatally DES- and tamoxifen-treated mice was lower than that in the controls at 2-15 months of age. Contents of Ca and P of pelvis and femur in neonatally tamoxifen-treated mice were lower than in the controls and neonatally DES-treated mice. In neonatally DES-treated mice at 6-12 months, Ca and P contents in the pelvis were lower than in controls, but not different in the femur. The number of osteoblasts per unit length of endocortical surface of the femur in 2- and 3-month-old DES- and tamoxifen-treated mice was lower than that in the controls. The osteoclast number in the femur in DES-treated mice at 2 to 12 months was not different from that in the controls; however, in tamoxifen-treated mice, the number was higher than in the controls. An epiphyseal line was clearly detected in the femur of 12- and 15-month-old DES- and tamoxifen-treated male mice, whereas the line in the controls disappeared after 12 months.

CONCLUSIONS

The present results indicate that in male mice, neonatal exposure to DES and tamoxifen induced permanent changes in the pelvis and the femur, and that tamoxifen had a greater effect on bone tissue than did DES.

Partial characterization of binding sites of VA-045, a novel apovincaminic acid derivative, in rat brain membranes

1. We characterized the binding sites of VA-045 [(+)-eburunamenine-14- carboxylic acid (2-nitroxyethyl)ester] in the rat brain. 2. VA-045 showed no affinity for various types of well-known neurotransmitter-related receptors or channels. However, radiolabeled VA-045 ([3H]VA-045) bound to rat brain membranes in a saturable and reversible manner. The Kd and Bmax values of [3H]VA-045 binding were 58.2 nM and 2685 fmol/mg of protein, respectively. 3. The largest specific binding of [3H]VA-045 was observed in the cerebellum, among seven brain regions, and in subcellular synaptosomes. 4. Specific binding of [3H]VA-045 was inhibited by VA-045 (Ki = 0.06 microM), a levorotatory enantiomer of VA-045 (VA-213) and its structural analog, vinpocentine. Moreover, compounds with calmodulin antagonistic activity inhibited the [3H]VA-045 binding. 5. These results suggest that VA-045 binds to specific sites, which may resemble calmodulin, on synaptic membranes in the brain.

[The relief of postoperative pain by suppositories of buprenorphine or NSAID]

We evaluated the effects of suppositories of buprenorphine (BN) or NSAID (supp.) preoperatively administered for postoperative pain relief in patients who underwent elective gynecological surgeries. Fifty six patients were randomized into four groups: group B; 0.4 mg BN supp., group B+I; 0.4 mg BN supp. and 50 mg indomethacine (IND) supp., group B+D; 0.4 mg BN supp. and 50 mg diclofenac supp., group C; no supp. given as control. They were administered rectally after induction of general anesthesia. In all the supp. groups the patients had good pain relief during the first 24 hrs after the administration of supp. Group B+I seemed to have better pain relief, but, there was no statistical significance among the 3 groups. Nausea and vomiting were observed more frequently in group B and in control group C than in NSAIDs combined groups. The difference in the incidence rates was not significant. In conclusion, the simultaneous administration of BN and IND supp. was considered to be useful for postoperative pain relief without producing major side effects.

Heparin and heparan sulfate block angiotensin II-induced hypertrophy in cultured neonatal rat cardiomyocytes. A possible role of intrinsic heparin-like molecules in regulation of cardiomyocyte hypertrophy

BACKGROUND

Heparan sulfate, one of the primary components of extracellular matrix, is a potent antigrowth factor in certain types of cells. To elucidate a possible role of endogenous heparin-like molecules in regulating cardiomyocyte hypertrophy, we investigated the effects of heparin and heparan sulfate on angiotensin (Ang) II-induced hypertrophy in cultured neonatal rat cardiomyocytes.

METHODS AND RESULTS

Competitive [3H]heparin binding assay showed that cardiomyocytes had specific binding sites for heparin. In situ [3H]heparin binding assay demonstrated that heparin, which rapidly bound to the cardiomyocyte surface, was subsequently accumulated around the nuclei, suggesting that heparin might work in the nucleus. Cotreatment with heparin (20 micrograms/mL) completely inhibited increased cell surface area by Ang II (10(-6) mol/L). Increased [3H]leucine incorporation by Ang II was reduced by heparin dose-dependently. The inhibitory effect of heparin on Ang II-induced cardiomyocyte hypertrophy also was confirmed by Northern blot analysis: heparin dose-dependently inhibited skeletal alpha-actin and atrial natriuretic peptide gene expression, genetic markers for cardiomyocyte hypertrophy. Heparan sulfate showed similar inhibitory effects on cell surface area, [3H]leucine incorporation, and skeletal alpha-actin gene expression. Treatment with heparinase I or III, which specifically digests the disaccharide chains of endogenous heparin-like molecules, upregulated protein synthesis and skeletal alpha-actin and atrial natriuretic peptide gene expression in cardiomyocytes.

CONCLUSIONS

Our findings in this study strongly suggest that heparin and heparan sulfate are potent inhibitors of cardiomyocyte hypertrophy and that endogenous heparin-like substances negatively regulate cardiomyocyte hypertrophy.

ATP-sensitive K+ channel openers block sulpiride-induced dopamine release in the rat striatum

In vivo brain microdialysis was used to investigate the role of ATP-sensitive K+ (KATP) channel openers in dopamine release regulated by dopamine autoreceptors in the rat striatum. Local infusion of two KATP channel openers, nicorandil (10(-5)-10(-3) M) and cromakalim (10(-5)-10(-3) M), into the striatum thorough the dialysis membrane produced dose-dependent decreases in extracellular concentrations of dopamine. Local application of the dopamine D2 receptor antagonist, (-)-sulpiride (10(-5) M), produced significant increases in extracellular concentrations of dopamine. Both nicrorandil (10(-5) M) and cromakalim (10(-4) M) blocked significantly (-)-sulpiride (10(-5) M)-induced increases in dopamine levels in the striatum. These results suggest that activation of KATP channels in the striatum causes decreases in endogenous dopamine release in vivo. Furthermore, the sulpiride-induced increases in dopamine levels caused by blocking the tonic activation of dopamine autoreceptors were inhibited by activation of KATP channel. These data indicate that KATP channels may be present in nigrostriatal dopaminergic terminals and that striatal dopamine autoreceptors inhibit dopamine release tonically by activation of KATP channels.

Simple and selective assay of 4-hydroxymephenytoin in human urine using solid-phase extraction and high-performance liquid chromatography with electrochemical detection and its preliminary application to phenotyping test

A simple and selective HPLC method for the determination of 4-hydroxymephenytoin (4-OH-M) in human urine, using a controlled potential coulometric detector equipped with a dual working electrode cell of fully porous graphite, has been developed. After acid hydrolysis of urine, 4-OH-M and the internal standard (I.S.), 5-hydroxy-1-tetralone, were extracted from urine by means of a Bond Elut Certify LRC column. The extracts were chromatographed on a reversed-phase mu Bondapak C18 column using methanol-50 mM KH2PO4 (pH 4.0) (30:70, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. Electrochemical detection at applied potential of 800 mV resulted in a limit of quantitation of 0.76 micrograms/ml. The method showed a satisfactory sensitivity, precision, accuracy, recovery and selectivity. The present method was applied to the phenotyping test in thirteen Japanese healthy volunteers who received an oral 100-mg racemic mephenytoin. The phenotypes determined by the present method were found to be in agreement with those obtained with the reported customary assay based on gas chromatography.

Multiseptate gallbladder: biliary manometry and scintigraphy

A 30-year-old man with multiseptate gallbladder, a very rare congenital anomaly, is presented. His presenting symptom was epigastric pain. A hypoplastic gallbladder with multiple septa was demonstrated by ultrasonography and endoscopic retrograde cholangiography. An injection of cerulein reproduced pain, and simultaneous biliary manometry and scintigraphy showed impairment of gallbladder filling and emptying. Laparoscopic cholecystectomy resulted in complete relief of the pain. Biliary manometry and scintigraphy are useful to determine the operative indication in a symptomatic patient with this entity.

Endothelin-1 and its receptor in hypertrophic cardiomyopathy

Endothelin-1, a potent vasoconstrictor produced by vascular endothelial cells, activates the hypertrophic program in cultured heart muscle cells. However, the role of endothelin-1 in cardiac hypertrophy in humans is unknown. Therefore, we studied hypertrophic cardiomyopathy patients with normal pulmonary arterial pressure, in whom cardiac hypertrophy is a specific feature of the disease. Radioimmunoassay with a monoclonal antibody to human endothelin-1 showed that the plasma level of immunoreactive endothelin was more than twofold higher in hypertrophic cardiomyopathy patients than in control subjects (P < .005). In situ hybridization analysis of endomyocardial biopsy specimens showed positive signals of endothelin-1 type A receptor mRNA in ventricular myocytes of all specimens. The receptor expression in ventricular myocytes was similar between hypertrophic cardiomyopathy patients and control subjects. We propose that endothelin-1 might represent an important factor involved in hypertrophic cardiomyopathy. Whether endothelin-1 plays a causal role in cardiac hypertrophy or is a marker of its occurrence needs to be clarified.

[Use of scintigraph in the diagnosis of pulmonary sequestration]

To evaluate scintigraphic findings in cases of pulmonary sequestration, perfusion lung scintigrams were obtained with Tc-99m macroaggregated albumin, and radionuclide angiocardiograms were obtained with Tc-99m pertechnetate in 5 cases of pulmonary sequestration. Perfusion lung scintigrams showed well-defined, segmental perfusion defects in the left lower lobe adjacent to the diaphragm, including S8, S9, and S10. The radionuclide angiocardiograms delineated abnormal systemic blood flow through the descending aorta to the left lower lobe. Subtraction scintigrams were obtained from two images of different phase in the aortic phase on the radionuclide angiograms; these images showed the abnormal systemic blood flow through the descending aorta more clearly than did the conventional radionuclide angiocardiograms. Thus, perfusion lung scintigrams and radionuclide angiocardiograms may be useful as non-invasive aids in the diagnosis of pulmonary sequestration.

Idiopathic hypertrophic cranial pachymeningitis associated with hydrocephalus and myocarditis: remarkable steriod-induced remission of hypertrophic dura mater

We describe a patient with idiopathic hypertrophic cranial pachymeningitis (IHCP) associated with hydrocephalus and myocarditis in whom steroids caused remission of the hypertrophic dura and enlarged ventricles. Myocarditis induced complete atrioventricular block that responded to steroids initially but later required permanent pacemaker implantation. Serum ANA and anti-dsDNA antibody were positive. Our case suggests that IHCP and myocarditis may share a common autoimmune etiology.

Exogenous nucleotides alter the proliferation, differentiation and apoptosis of human small intestinal epithelium

The turnover of intestinal epithelial cells is a finely regulated process extending from undifferentiated crypt stem cells to terminally differentiated villus cells. The final phase of this maturation process is apoptosis and extrusion. Recent studies have shown that programmed cell death (PCD) occurs not only in senescent cells and in rapidly developing tissues but also in response to cellular stress preventing damaged cells from entering uncontrolled proliferation without repair. This study examined the role of exogenous nucleotides on cell proliferation, differentiation and apoptosis in organ cultures of human fetal small intestine. The addition of adenosine monophosphate (AMP), a putative stress reactant, to the culture media resulted in the suppression of crypt cell proliferation followed by the restoration of differentiation and the induction of apoptosis across a broad range of villus epithelium when compared with controls without added nucleotide. In contrast, the addition to cytidine monophosphate (CMP) to the culture media did not increase apoptosis, despite the nucleotide being taken up by the fetal small intestine in a similar dose- and time-dependent manner to AMP. Furthermore, Bax mRNA, an apoptosis-inducer gene, was increased with addition of AMP, suggesting that the induction of apoptosis may be channeled through the p53 pathway. These results suggest that a specific exogenous nucleotide, AMP, may have an important role in controlling the dynamic balance of cellular turnover in the developing human small intestine.

Enhancement of pressor response to ephedrine following clonidine medication

We studied pressor responses and changes in plasma catecholamine concentrations following two consecutive doses of ephedrine 0.1 mg.kg-1 with (n = 20) and without (n = 20) clonidine 5 micrograms.kg-1 premedication in patients presenting for a variety of major surgical procedures under general anaesthesia. Arterial blood pressure and heart rate were measured at 1 min intervals for 10 min, and plasma catecholamines were measured before and 3 min after each dose of ephedrine. Mean blood pressure changes from the baseline values were greater in the clonidine than in the control group 3-8 min and 4-9 min following the first and the second doses of ephedrine, respectively (p < 0.05). Plasma catecholamine concentrations tended to be lower in the clonidine group throughout the study. The augmented pressor response to ephedrine in clonidine-treated patients can be attributed to enhanced cardiovascular response rather than clonidine-induced accumulation and subsequent increased release of catecholamine.

Simple-spike activity of floccular Purkinje cells responding to sinusoidal vertical rotation and optokinetic stimuli in alert cats

To understand how the cerebellar flocculus is involved in the processing of semicircular canal signals in the vertical vestibulo-ocular reflex (VOR), we analyzed the simple-spike activity of floccular Purkinje (P) cells that was modulated by sinusoidal pitch rotation, and then analyzed their activity during presentation of sinusoidal vertical optokinetic stimuli in alert, head-fixed cats. The great majority of P cells also responded to optokinetic stimuli with peak discharge near peak stimulus velocity. Eighty percent of P cells that responded to both pitch and optokinetic stimuli showed increased activity when the directions of the resultant eye movements were the same. During rapid modification of the VOR induced by visual pattern movement, modulation amplitudes of the cells tested increased together with the eye velocity increase. Maximal activation directions of these cells studied during vertical rotation in many planes were near the vertical canal planes, similar to those in our previous studies. The remaining 20% of P cells showed increased discharge for the same direction of stimulus movement. These results suggest that the activity of the majority of pitch-responding P cells contains, at least partly, a vertical eye velocity component during presentation of vestibular or optokinetic stimuli in addition to canal inputs during pitch rotation.

In vitro effects of eicosanoid synthesis inhibitors in the presence of linoleic acid on MDA-MB-231 human breast cancer cells

We investigated the effects of cyclooxygenase and lipoxygenase inhibitors in the presence of linoleic acid (LA), as well as the direct effects of prostaglandin E (PGE) and leukotriene B (LTB) on a human breast cancer cell line (MDA-MB-231) in vitro. Piroxicam, esculetin, and nordihydroguaiaretic acid (NDGA) suppressed cell growth and thymidine incorporation. However, a low concentration (1 microgram/ml) of indomethacin (INDO) stimulated cell growth and thymidine incorporation, while a high concentration of INDO (30 micrograms/ml) inhibited both. Esculetin and NDGA reduced the secretion of LTB, whereas piroxicam reduced the secretion of PGE. INDO reduced the secretion of PGE, but a low concentration of INDO increased the secretion of LTB. Consequently, cell growth was correlated with the PGE and/or LTB concentrations when the cells were treated with these cyclooxygenase or lipoxygenase inhibitors. On the other hand, exogenous PGE2 partially reversed the inhibition of thymidine incorporation caused by INDO, whereas LTB4 exerted a similar effect in the case of esculetin or NDGA. The reversibility of the piroxicam effect with PGE2 is not convincing. Therefore, it is suggested that the growth of MDA-MB-231 cells in vitro is affected by both the lipoxygenase and cyclooxygenase products, probably the other eicosanoids rather than PGE2 and LTB4.

In vivo uptake of lecithin-coated polystyrene beads by rat hepatocytes and sinusoidal endothelial cells

BACKGROUND

While phagocytosis by Kupffer cells (stellate perisinusoidal macrophages) is well known and that by endothelial cells also is thought to occur under certain conditions, the uptake of large particles by hepatocytes has not been well studied. We reported previously the selective phagocytic uptake of material by hepatocytes using egg lecithin-coated silicon particles. In the present work, we describe more precisely this process following the injection of lecithin-coated polystyrene beads. Additionally, we consider the possible significance of the transcytotic action by endothelial cells.

METHODS

Polystyrene latex beads (240 nm in diameter) composed of two layers of polystyrene and methyl methacrylate with a central void cavity and diameter of 140 nm were injected into male Wister-Imamichi rats. The injections were administered through the hepatic portal vein in a volume of 3 ml (concentration of the lecithin-coated or uncoated beads was 2 mg/ml). Controls received the lecithin alone at a concentration of 2 mg/ml. Liver samples were taken 5, 10, or 15 min after injection, fixed, and processed for ultrastructural analysis.

RESULTS

Both lecithin-coated and noncoated beads were mainly incorporated in the Kupffer cells as well as in the endothelial cells. Bristle-coated invaginations were observed in the uptake by both cell types; however, noncoated invaginations were also active in the endothelial cells, especially on the surface facing the perisinusoidal space of Disse. Only coated beads were observed within the space or in the hepatocytes. Once taken up by the hepatocytes, the lecithin-coated beads were found either within lysosomes or in a free state in the cytoplasm.

CONCLUSIONS

Uptake of 240 nm lecithin-coated polystyrene beads was observed by Kupffer cells, endothelial cells and hepatocytes. These beads were considered to be transported across the endothelial cells by transcytosis. Pseudopodia and bristle-coated invaginations were not employed by the hepatocytes when incorporating the beads.

Elevated tyrosine hydroxylase mRNA levels in medulla oblongata of spontaneously hypertensive rats

The present study has investigated the expression of tyrosine hydroxylase (TH) mRNA and its activity in medulla oblongata of spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). The TH mRNA levels were determined by Northern blot and dot blot analyses. The TH activity and the expression of TH mRNA in medulla oblongata of SHR were significantly higher than those of WKY. These results suggest that the hypertension of SHR may be related to the high activity of TH due to the high level of TH mRNA which increases norepinephrine levels in the medulla oblongata.