Oil film behavior under minute vibrating conditions in EHL point contacts

The oil film thickness was measured under conditions of minute vibrations using an elastohydrodynamic lubrication (EHL) ball-on-disk test rig. Poly-alpha-olefin (PAO) oil was used as the lubricant under conditions of pure sliding where only the ball specimen was minutely vibrated. It was found that an oil film formed when the amplitude ratio was greater than 1.6. Moreover, when conditions were changed to the maximum vibrating speed, oil viscosity, and maximum contact pressure, the critical amplitude ratio at which the oil film began to form remained at 1.6. Consequently, calculated results showed that the oil film was formed when the amplitude ratio was π/2 (nearly equal to 1.6), which closely agreed with our test results.     

Electrochemical removal of p-nonylphenol from dilute solutions using a carbon fiber anode

p-Nonylphenol, which is widely used as raw material in industrial activities has been regarded as an environmental endocrine disrupter. In an effort to develop a new treatment method for p-nonylphenol, we initially investigated the electrochemical behavior of p-nonylphenol by voltammetric techniques. The electrochemical oxidation of p-nonylphenol led to the formation of electropolymerized film on the glassy carbon electrode surface. The fouling on the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferrocyanide ions as the redox marker. The electrochemical removal of p-nonylphenol based on the formation of the electropolymerized film on an anode surface was performed using a carbon fiber (CF) with a very large surface area. The high removal efficiency for p-nonylphenol was obtained by applying a potential at 0.7 V. The maximum surface coverage of electropolymerized p-nonylphenol on the CF was about 5 x 10(-9) mol/cm2. The presence of humic acid hardly inhibited the removal of p-nonylphenol. Furthermore, the application to the removal of phenol, o-chlorophenol, p-chlorophenol, 2,4-dichlorophenol, and 2,4,5-trichlorophenol was attempted by using this method.     

Mutations of the transforming growth factor-beta type II receptor gene are strongly related to sporadic proximal colon carcinomas with microsatellite instability

BACKGROUND: Mutations of the transforming growth factor-beta type II receptor gene (TGF-beta RII) have been found in several replication error-positive sporadic colorectal carcinomas and hereditary nonpolyposis colorectal carcinoma cell lines. The aim of this study was to clarify the role of TGF-beta RII in sporadic colorectal carcinogenesis. METHODS: The authors screened for mutations at simple repeated sequences in the TGF-beta RII gene by polymerase chain reaction-single strand conformation polymorphism. They also examined genomic instability, using five microsatellite DNA markers in 69 sporadic colorectal carcinomas. When the carcinomas exhibited the TGF-beta RII mutations, the authors screened further for mutations in two DNA mismatch repair genes, hMSH2 and hMLH1. RESULTS: Seven of the 69 cancers (10%) showed one or two A deletions in TGF-beta RII and resultant frameshift mutations in nucleotide positions 709-718 containing a (A) 10 repeated sequence; but none of these appeared in the corresponding normal DNA, indicating a somatic mutation. All of the seven cancers were located in the proximal colon; there were none in the distal colon (P < 0.01). On the other hand, 22 of the 69 carcinomas (32%) showed the replication error-positive phenotype. The frequency of replication errors in proximal colon carcinomas was higher than that in distal colon carcinomas (P < 0.05). All 7 cancers with TGF-beta RII mutations showed replication errors. One of them revealed a nonsense mutation at codon 413, and 1 revealed a loss of heterozygosity in hMSH2. CONCLUSIONS: These data indicate that mutations of TGF-beta RII are strongly related to proximal colon carcinomas with microsatellite instability and that the mechanism of carcinogenesis in some proximal colon carcinomas is similar to that in hereditary nonpolyposis colorectal carcinoma.     

Synthetic lipid A produces antitumor effect in a hamster pancreatic carcinoma model through production of tumor necrosis factor from activated macrophages

The antitumor effect and biological activities of a newly synthesized lipid A analogue (ONO-4007) were investigated in a hamster pancreatic carcinoma model. Marked and dose-dependent inhibition of tumor growth was achieved by i.p. injection twice a week for 3 weeks of 10, 30 or 50 mg/kg of ONO-4007. Endogenous tumor necrosis factor (TNF) activities induced by ONO-4007 were significantly greater in tumor than in serum, spleen and liver. TNF production by macrophages stimulated with ONO-4007 after culture was much greater when culture was performed in the presence of hamster pancreatic carcinoma cells (no cell-to-cell contact). It was further found that the cytotoxic activity of TNF secreted by macrophages cultured with cancer cells was inhibited in the presence of anti-TNF neutralizing antibodies. These findings suggest that ONO-4007 displays antitumor effects by stimulating production of endogenous TNF in tumor macrophages, possibly through activation by soluble macrophage-stimulating factors in cancer cells.     

The secretory intestinal transport of some beta-lactam antibiotics and anionic compounds: a mechanism contributing to poor oral absorption

PURPOSE: To measure the effect of silicon diode detectors used for in vivo dosimetry on beam characteristics and determine whether this effect is clinically significant. METHODS AND MATERIALS: Commercially available photon and electron diodes were placed on the central axis of photon and electron beams. The beam characteristics were measured for 6- and 10-MV photon and 6-20-MeV electron energies from a Varian Clinac 1800 medical linear accelerator. Water was used for the medium, and measurements were made for various clinically common field sizes and depths. RESULTS: Beam attenuations along the central axis were 10 and 7.5% for 6- and 10-MV photons, respectively. Electron beam dose reductions were between 13 and 25% for 20-6-MeV electrons. Photon beam flatness varied up to 7% at different depths, but the symmetry was not affected much. Electron beam flatness and symmetry were significantly changed to as much as 18 and 6%, respectively. CONCLUSION: Use of diode detectors on central axis of photon and electron beams for in vivo dosimetry causes significant attenuation and alteration of the beam characteristics. The percentage of the volume affected is significant (e.g., 23% of the volume in a 4 x 4 field gets 10% less dose for a 6-MV photon beam), especially if these diodes are used for in vivo dosimetry on the central axis every day for every treatment, as is done in some clinics. Other beam parameters such as penumbra and skin dose are also affected. It is therefore recommended that the diodes be used only as needed.     

Genetic evidence that the Lewy body variant is indeed a phenotypic variant of Alzheimer''s disease

To investigate the role of cyclic adenosine monophosphate (cAMP) in penile erection in relation to the effect of prostaglandin E1 (PGE1) male adult New Zealand white rabbits were utilized as a model to study intracavernous pressure (ICP) in vivo. After intracavernous injection of PGE1 (0.2-1.6 micrograms/kg) and 8-bromocyclic adenosine monophosphate (8-Br-cAMP, 0.5-1.5 mg/kg), both drugs raised the ICP in a dose-dependent manner. The increased ICPs induced by PGE1 and 8-Br-cAMP were 33.4 +/- 8.12 and 24.1 +/- 4.9 mm Hg, respectively (p < 0.05, paired Student's t test). Administrations of cyclic adenosine monophosphothioate, Rp-isomer (cAMP antagonist, 0.02-0.08 mumol/kg) prior to PGE1 injections inhibited the effect of PGE1 in vivo in a dose-dependent manner. The systemic blood pressures and heart rates in rabbits were unchanged during all the intracavernous injections. The corpus cavernosal tissues isolated from rabbits were studied for the cAMP contents after incubation of different doses of PGE1 in vitro. The cAMP contents were also elevated in a manner parallel with the increases in PGE1 concentrations (3-9 microM). We conclude: (1) the feasibility of intracavernous injection of vasoactive drugs is similar to that in man, thus the rabbit can be used as a suitable alternative for the studies of penile erection, and (2) cAMP is mediated in PGE1-induced relaxation of the rabbit corpus cavernosum, and the cAMP system only participates partially in penile erection.     

Transplantation of the fetal olfactory placode restores reproductive cycles in female rhesus monkeys (Mucaca mulatta) bearing lesions in the medial basal hypothalamus

The purpose of this study was to determine whether loss of the reproductive cycle after lesions of the medial basal hypothalamus can be reversed by transplantation of the embryonic olfactory placode (OP) into female rhesus monkeys. Seven adult female rhesus monkeys with regular menstrual cycles received bilateral radiofrequency lesions in the arcuate nucleus and the median eminence. After confirmation of anovulation in these monkeys, four monkeys were stereotaxically implanted with the OP obtained from monkey fetuses on embryonic days 35-36. The remaining three monkeys were similarly implanted with embryonic cerebellum (CB) as a control. Fetuses were delivered by cesarean section, and the OP and CB were immediately dissected out using a stereomicroscope. Fetal tissue was then cut into small pieces (< 1 mm3), mixed with artificial cerebrospinal fluid containing small pieces of Gelfoam, and stereotaxically injected into the infundibular recess of the third ventricle. The recovery of ovulatory cycles in recipient monkeys was observed for at least 6 months; sex skin color changes and menstrual records were obtained daily, and serum samples for LH, estrogen, and progesterone were obtained twice a week. Three of four OP-transplanted monkeys resumed their ovulatory cycles within 2 months, whereas the fourth monkey, an elderly female, failed to recover her cycle. In contrast, none of the three CB-transplanted monkeys resumed ovulatory cycles. Histological examination indicated that 1) lesion scars were present in the median eminence-stalk region as well as the medial basal portion of the arcuate nucleus of all seven brains; and 2) cartilage was present in the third ventricles of the OP-implanted brains. Moreover, immunocytochemical staining revealed that in all OP monkeys, small, round, and immature LHRH-positive cells with fine short processes were found in the third ventricle and/or median eminence-stalk region, whereas no similar LHRH cells were found in CB-transplanted monkeys. It is concluded, therefore, that implantation of LHRH neurons derived from the fetal OP can result in resumption of the ovulatory cycle in female monkeys whose own LHRH pulse-generating mechanisms were impaired. Moreover, the results suggest that LHRH neurons derived from embryonic OP possess the physiological functions necessary for the stimulation of gonadotropin secretion.     

Extracorporeal shock wave lithotripsy on patients with spinal cord injury with special reference to autonomic hyperreflexia

We performed treatment of urolithiasis on 7 patients with spinal cord injury (6 males and one female, with a mean age of 41 years old) by extracorporeal shock wave lithotripsy (ESWL) using a Lithostar (Siemens). The level of injury was cervical in 3 patients and lower thoracic in 4. The treated stones were renal in 6 patients, including one staghorn caliculus, ureteral in 2, and bladder stones in 2 patients. ESWL was performed under general anesthesia in 2 patients, and in another patient, epidural anaesthesia was employed in the first several sessions, but thereafter treatment was safely continued with no anesthesia. The other 4 patients were treated without anesthesia. In most patients, the stones (9 stones in 6 cases) were easily disintegrated after treatment of from one to 14 sessions, except one case of staghorn caliculus, and the clearance of fragments was also satisfactory. In one patient, hypertension and bradycardia due to autonomic hyperreflexia were observed during ESWL, and the treatment was discontinued, but the stone was successfully disintegrated and the fragments were voided. In another patient, autonomic hyperreflexia was observed while the fragments passed through the ureter, although no signs of this reflexia were seen during the ESWL procedure.     

The relationship of IL-6 to hormonal mediators, fuel utilization, and systemic hypermetabolism after surgical trauma

OBJECTIVES: To define the relationship between inflammatory cytokines, hormonal mediators, alteration of energy substrate and hypermetabolism during the early phase after surgical trauma. DESIGN: A prospective case-control study of 13 patients underwent elective surgery for carcinoma between November 1993 and January 1995. MATERIALS AND METHODS: They received parenteral supply of adequate glucose and amino acids through central venous catheter after surgery equally. Inflammatory cytokines such as TNF- alpha, IL-1 and IL-6, stress hormones such as norepinephrine, glucagon and insulin, and fuel utilization and hypermetabolism variables such as resting energy expenditure (REE), CRP, free fatty acid, respiratory quotient, the calculated rates of glucose and fat oxidation using indirect calorimetry were measured serially (the day before operation, the end of surgery, and postoperative day (POD) 1, 2 and 5). MEASUREMENTS AND MAIN RESULTS: TNF- alpha and IL-1 were not detected during the study period. Initial elevation and steady decline of IL-6 concentrations were seen after surgical injury, and this response related significantly to post-operative norepinephrine and glucagon levels throughout the study period, and to insulin levels only at the end of surgery. %REE (REE/BEEHB; basal energy expenditure according to the Harris-Benedict equation) on POD 2 and 5, and all CRP levels after surgery were significantly related to IL-6 levels more than hormone levels. Fuel utilization variables on POD 2 were related to both IL-6 and hormone levels. CONCLUSIONS: Initial elevation of IL-6 concentration might induce stress hormones such as norepinephrine and glucagon, but not insulin after surgical trauma. Moreover not only hormonal mediators but also cytokine such as IL-6 are responsible for the development of the stress response of the alteration of energy substrate and hypermetabolism.