Effects of particulate high-density polyethylene and titanium alloy on tissue ingrowth into bone harvest chamber in rabbits

The purpose of this study was to determine whether small, phagocytosable particles of titanium alloy (Ti) and high-density polyethylene (HDPE) have an adverse effect on bone ingrowth. The bone harvest chamber (BHC) was implanted bilaterally in the proximal tibial metaphysis of six mature rabbits. The BHC has a transverse 1-mm wide pore providing a continuous canal through the chamber for tissue ingrowth. After an initial 6-week period for osseointegration of the BHC, the contents of the canal were harvested repeatedly at 3 weekly intervals. This could be done with the chamber in place, without disturbing its exterior surface or the surrounding bone. The carrier solution, 1% sodium hyaluronate (Healon) was implanted first. In subsequent implantations, Healon was mixed with particles of HDPE or Ti averaging 4.7 +/- 2.1 and 3.0 +/- 2.6 microns, respectively. The contralateral chamber was left empty and served as a control. The chambers were harvested repeatedly, alternating experimental and control sides. The sections from the control side, and those containing Healon alone demonstrated extensive trabecular bone in a fibrovascular stroma. The sections containing Ti alloy particles were qualitatively and quantitatively similar to the control sections and those containing Healon, except for the presence of small black granules of Ti alloy, dispersed in the fibrovascular stroma or phagocytosed by scattered macrophages. The sections containing HDPE particles were infiltrated and engulfed by mononuclear and multinuclear histiocytic cells in a highly fibrous stroma. The majority of the multinucleated cells present were interpreted as being foreign body giant cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Intermittent micromotion and polyethylene particles inhibit bone ingrowth into titanium chambers in rabbits

We performed a histomorphological and morphometric analysis of the effects of short daily periods of micromotion and phagocytosable particles of high density polyethylene (PE) on bone ingrowth into a 1 x 1 x 5 mm canal within a titanium chamber in rabbits. The micromotion chamber (MC) was implanted in the tibia of nine mature New Zealand white rabbits. After osseointegration and first harvest of tissue, 40 micromotions (amplitude = 0.5 mm) were applied daily at a rate of 1 Hz for a 3-week period. The tissue within the chamber was then harvested. For the second treatment, PE particles (10(8)/mL) were placed within the canal. The tissue in the chamber was harvested 3 weeks later. The next treatment was a 3-week rest period, in which neither micromotion nor particles were utilized; a harvest followed. The final treatment combined PE particles and micromotion, followed by a harvest 3 weeks later. Sections from control harvests contained extensive trabecular bone arranged longitudinally throughout the canal in a fibrovascular stroma. Micromotion produced longitudinally oriented fibrous tissue within the chamber. PE particles were associated with macrophages, surrounding and engulfing the birefringent particles. The combination of particles and micromotion produced a fibrous stroma laden with macrophages. PE particles and micromotion, alone or together, produced a similar effect in inhibiting bone ingrowth, compared to nonmoved chambers without particles. In this short-term experiment, no additive or potentiating effect of these two stimuli could be demonstrated.

[Liposculpture with tumescent technique]

This article summarized our experiences in using the tumescent technique to treat 18 patients with local fat deposit. The tumescent technique is a new technique for liposuction. It is atraumatic, less blood loss during operation, and more radical suction of local fat deposit. It is safe and effective. A new set of instrument for liposuction that was designed by us is also introduced.

[Evaluation of the effects of intermittent iron supplement on iron-deficiency anemia in children]

A three-month iron supplement trial was conducted in 238 preschool children, who were divided randomly into three groups supplemented with oral administration of iron preparation at the same dose everyday, every other two days, and each week, respectively, to avoid low-absorption and side-effects of oral iron preparation and to evaluate its preventive and treatment effects and side-effects. Results showed individual iron-supplement by once every other two days or each week was efficient as same as by once everyday in improving anemia and increasing serum ferritin level. It can also reduce transient iron overload and gastrointestinal side-effects caused by daily iron supplement.

The incidence of drug resistant tuberculosis in 1279 Korean patients

OBJECTIVES

In the past decade, the incidence of tuberculosis has been decreased in Korea and the nationwide survey of tuberculosis from 1965 through 1990 suggested a declining tendency of resistant organisms. But the prevalence rate of multidrug resistance of Mycobacterium tuberculosis is still a serious problem in Korea, and the aim of this study is to check the drug resistance pattern in the patients visiting University Hospital, the 3rd referral center.

METHODS

We reviewed 1279 cases (522 female, 757 male, mean age 39.4 +/- 16.7) of bacteriologically proven tuberculosis seen during the period from 1986 to 1992 retrospectively. Of 1093 patients, who were indentified in previous medical history, 454 (41.5%) had a history of prior antituberculous chemotherapy.

RESULTS

Resistance rate (resistant to 1 or more drugs) was 33.9%. Eleven percent of patients had resistance to a single drug (INH: 80.6%). Twenty two percent of patients had resistance to 2 or more drugs. Resistance rate is higher (47.4%) in the patients with a history of prior treatment than without a history (25.5%).

CONCLUSIONS

These data suggest that the high rate of multidrug resistance in Korea did not show any decreasing tendency. So, mycobacterial culture and sensitivity tests should be recommended at initial treatment of tuberculosis and potent antituberculosis drugs are strongly recommended.

Comparative regulation of inhibin, activin and human chorionic gonadotropin production by placental trophoblast cells in culture

In the present study, we investigated the roles of cyclic adenosine monophosphate (cAMP), intracellular calcium, glucocorticoids, protein kinase-C and gonadotrophin-releasing hormone (GnRH) in regulating human chorionic gonadotrophin (hCG), inhibin and activin production in cultured human term placental trophoblast cells. Inhibin and hCG were measured in conditioned media by radioimmunoassay, while putative forms of inhibin and activin were characterized by western blotting using affinity-purified antisera directed against the inhibin alpha- and beta A-subunits. Inhibin and hCG secretion were stimulated by dexamethasone (0.2 microM), GnRH (5-25 microM), calcium ionophore A23187 (0.2-1 microM), phorbol-12-myristate-13-acetate (22 nM) and epinephrine (1 microM), with increasing response over successive 24-h treatment periods. Two molecules Mr approximately 30 and 32 kDa appeared to be the predominant dimeric forms of inhibin secreted by the cells, while 26 kDa activin was present in excess over inhibin. Large amounts of 40-44 kDa protein were detected by the alpha-directed antisera only, which may be a form of the inhibin alpha-subunit precursor protein. Secretion of activin was responsive to phorbol ester-mediated stimulation but not to the presence of GnRH or elevated cAMP concentrations. The divergence in maternal serum inhibin and hCG concentrations during late pregnancy remains unexplained by these findings.

ATP promotes development of afterdepolarizations and triggered activity in cardiac myocytes

The effect of extracellular ATP on transient inward current (Iti), delayed afterdepolarization (DAD), early afterdepolarization (EAD), and triggered activity were investigated in guinea pig isolated ventricular myocytes. ATP alone did not induce afterdepolarizations nor did it significantly alter the resting membrane potentials and action potentials. However, when it was applied with drugs known to increase intracellular Ca2+, ATP facilitated the induction of afterdepolarizations and triggered activity in approximately 60% of the cells. In the presence of isoproterenol, ATP increased the amplitude of Iti and DADs by 55 and 206%, respectively, and caused increases in the amplitude of L-type Ca2+ current (ICa) and EADs, which occasionally led to triggered activity. Similarly, addition of ATP increased the amplitude of Iti and DADs induced by elevated extracellular Ca2+ by 110 and 83%, respectively. Ryanodine inhibited the ATP-induced increase in Iti but not the increase in ICa. In the presence of BAY K 8644 or quinidine, ATP not only further prolonged the action potential durations by 18 +/- 4 and 17 +/- 4%, respectively, but also increased the amplitude of EADs. The present results show a novel arrhythmogenic effect of extracellular ATP, which facilitates the genesis of triggered arrhythmias when Ca2+ influx is increased, probably by further increasing Ca2+ influx from extracellular medium and Ca2+ release from intracellular stores.

Melatonin implant decreases the density of 2[125I]iodomelatonin binding sites in the chicken spleen

Changes in 2[125I]iodomelatonin binding to the chicken spleen following disruption of the normal melatonin rhythm by a slow-release melatonin implant were investigated. Melatonin capsules were implanted in 6-week-old male and female chickens reared under 12 h light/12 h darkness. The mid-light and mid-dark serum melatonin was measured throughout the period of implantation. Spleen weight and characteristics of splenic 2[125I]iodomelatonin binding sites were studied during the mid-light at 4 or 8 weeks after implantation. Melatonin implantation disrupted the normal diurnal rhythm of serum melatonin and elevated the mid-light level to the control mid-dark value until 5 weeks after implantation. The melatonin implant caused a significant decrease in the density of 2[125I]iodomelatonin binding sites at 4 weeks after implantation while there were no significant changes in the binding affinity. The reduction in 2[125I]iodomelatonin binding may be a result of down-regulation of the melatonin receptors by elevated serum melatonin. Alternatively, it may be due to an indirect suppression of 2[125I]iodomelatonin binding sites by the elevated sex hormones since melatonin implants increased the levels of testosterone in the male and estradiol in the female. Implantation of melatonin capsules significantly increased the body and spleen weights in the male chicken. These weight changes may be partly explained by the anabolic and erythropoietic action of the increased circulating testosterone.

Ultrastructural study of the hemopoietic microenvironment in human fetal spleen

Reciprocal interactions between hemopoietic stromal cells and immature hemopoietic cells in human spleens obtained from 20 fetuses of 10-28 weeks gestation were observed by transmission electron microscopy and scanning electron microscopy. The close association of stromal cells with immature hemopoietic cells was confirmed under the electron microscope and a presumptive HIM (Hemopoietic inductive microenvironment) was visualized. In regions of immature hemopoietic cell-reticular cell, endothelial cell, macrophage and interdigitating cell contact, some communicating structures were found between the plasma membranes of adjacent cells; moreover, the cytoplasm of these four stromal cells were full of various kinds of organelles. These results suggest that reticular cells, endothelial cells, macrophages and interdigitating cells are component parts of the HIM of human fetal spleen and that these cells have a nurturing function in relation to hemopoietic cells.

Cessation of strain facilitates bone formation in the micromotion chamber implanted in the rabbit tibia

Short, daily periods of externally-applied strain have been shown previously to affect the differentiation of mesenchymal tissue. In this study, we examine the effects of discontinuing a strain protocol known to produce primarily fibrous tissue rather than bone in the micromotion chamber (MC). Five MCs were inserted into the proximal tibial metaphysis of mature male New Zealand white rabbits. The MC has a 1 x 1 x 5 mm pore for tissue ingrowth. After osseointegration of the fixed outer cylinder of the chamber, the inner movable core was manipulated for 40 cycles per day delivered at a rate of 1 Hertz ('40'). This provided motion at the interface between the cylinder and the core. The tissue in the pore was harvested after 3 wks. The MCs were then manipulated at 40 cycles per day for 3 wks and then the manipulations were discontinued for 3 additional wks ('40 + 0'); the contents of the chamber were harvested after 6 wks. Finally, the chambers were left without manipulation ('0') and harvested after 3 wks. Histological sections from unmoved chambers ('0') contained extensive trabecular bone, embedded in a fibrovascular stroma. The '40' specimens were composed primarily of longitudinally orientated fibrous tissue. The '40 + 0' specimens were similar histologically to the '0' specimens. The amount of bone ingrowth expressed as a percentage of the area of the section averaged 37 +/- 6 (mean +/- standard error of the mean) for the '0' specimens, 20 +/- 2 for the '40' specimens and 37 +/- 7 for the '40 + 0' specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Photorefractive-crystal shape-parameter influence on formation of self-pumped phase conjugation

The influence of crystal-shape parameters on formation of self-pumped phase conjugation is studied experimentally. The parallelism of two c-cut faces of a barium strontium potassium niobate crystal of cuboid shape is changed to control the internal oscillation and thus to induce or to suppress the generation of self-pumped phase conjugation.

An in vitro study of femoral intramedullary pressures during hip replacement using modern cement technique

Five femora (four cadaveric and one plastic) were used to measure the intramedullary pressures simultaneously at two different locations along the proximal femur during the insertion of bone cement and the femoral component using modern cement technique. The pressures were monitored by transducers located at the midpoint of each femoral stem (P1), and just beyond the tip of the femoral stem proximal to a cement plug (P2). Transient increases in intramedullary pressure were noted during the initial compaction of the bone cement using a conventional device. However, during insertion of the femoral component, the pressures at P1 and P2 increased dramatically to peak pressures exceeding 2385 mm Hg at P1 and 3710 mm Hg at P2 respectively. These pressure elevations were not sustained; eight to 10 minutes after prosthesis insertion, the pressures decreased to below baseline levels in all five femora. This probably resulted from contraction of the cement during the curing phase. Transient elevations of intramedullary pressure to levels greater than 100 times capillary pressure are produced during hip replacement using modern cement technique. The highest pressures are generated during insertion of the femoral component rather than during the cement compaction step. These findings suggest that the use of a cement compactor to improve intrusion of the cement into bone is probably unnecessary.

[Transplantation of a minute artery to bridge over the defect of an artery of significantly larger calibre. An experimental study]

Based on our clinical experience for years of "unequal bite" suturing technique to perform end-to-end anastomosis of vessels with great discrepancy in diameter, the animal experimental study was carried out. An artery defect, 1.0-1.4 mm in diameter, was reunited with, an autogenous arterial graft of 0.3-0.4 mm in diameter. A high patency rate (96% in total) was obtained postoperatively. Histological examination by light microscope and scanning electron microscope showed that the unequal bite suturing technique can produce very smooth anastomotic junction and the minute arterial grafts healed well on a large artery. The unequal bite suturing technique is a very valuable development of the basic end-to-end anastomotic technique. A small autogenous arterial graft may be used to repair defect of an artery with large calibre clinically.

[The effect of trichosanthin on immunoregulatory T lymphocytes]

The effect of trichosanthin (TCS) on immune system has drawn attentions of the investigators both at home and abroad. The purpose of this study is to evaluate the prospects of TCS on autoimmune diseases and immunodeficiency diseases by detecting the immunoregulatory T lymphocytes (T8, 2H4, 4B4) count and cellular DNA content under the influence of TCS with flow cytometer using indirect immunofluorescence technique and lymphocyte culture in normal subjects and systemic lupus erythematosus patients. The results showed that the percentage of T8+ cells decreased, 4B4+ cells increased, 2H4+ cells did not markedly change after adding TCS. The raise of DNA content in S stage was dose-dependent to TCS, especially in large doses. It is concluded that TCS could selectively inhibit T8+ cells and could obviously increase the number of 4B4+ cells. It is suggested that TCS could enhance humoral immunity through the ratio of immunoregulatory T cells. So TCS might help immunodeficiency patients such as AIDS to reestablish their immune system.

Characterization of a monoclonal antibody directed against the carboxyl-terminus of human factor XIII. An epitope exposed upon denaturation and conserved across species lines

By deriving an anti-peptide monoclonal antibody, mAb 7A4, we characterized the relatively unstudied carboxyl-terminal end of the a-chain of human factor XIII, the plasma transglutaminase. MAb 7A4 was directed against the last eight amino acids (Gln-Ile-Gln-Arg-Arg-Pro-Ser-Met) and bound with a dissociation constant of 3.4 x 10(-8)M. In a solid assay format, mAb 7A4 bound equally well to factor XIII obtained from human plasma, platelets or placenta. However, in a solution-phase assay format, the epitope was largely unavailable but could be readily exposed by heat denaturation. Immunoblotting showed that this epitope is conserved among all species of plasma factor XIII tested except rabbit suggesting that the carboxyl-terminus might be an important structural element. Other competitive binding experiments with synthetic peptides as inhibitors pointed toward the final carboxyl-terminal amino acid, Met-731, as an immunochemically important determinant. This was used advantageously to confirm the finding that the carboxyl-terminal Met-731 is largely absent from placental factor XIII (1) as compared to platelet or plasma factor XIII.

[Retinal S-antigen and retinoblastoma--an immunohistochemical study]

A strain of monoclonal antibody, MabAgC6, which defines an epitope in S-antigen, was used to study S-antigen expression in 10 cases of retinoblastoma, where S-antigen immunoactivity was observed in different patterns: the "normal" photoreceptor elements incorporated in 3 cases of growing tumors, 3 of 4 fleurettes and E-W rosettes, and scattered tumor cells in 50% of the cases were stained positive. The results suggest that the expression of S-antigen in retinoblastoma may be used to assess the degree of tumor differentiation, as another of the tumor markers.

[Clinical observation on short term nutritional support in the treatment of advanced chronic obstructive pulmonary disease]

Twenty five patients with advanced chronic obstructive pulmonary disease (COPD) having malnutrition were randomly assigned to parenteral nutrition (PN) group (12 cases) and control group (13 cases). Patients in the PN group received 10% Intralipid and 5% Nutrisol-S. Body weight, blood lymphocyte, serum albumin, transferrin, prealbumin, fibronectin and serum free fatty acids (FFA) and serum free amino acids (AA) were monitored. The results showed that parenteral nutritional support for 10-20 days improved the nutritional status, significantly increased the body weight and the serum albumin, prealbumin, fibronectin, transferrin (P < 0.05 or P < 0.01) and some kinds of serum free amino acids: PaCO2 also decreased. Serum FFA remained under the normal level whether nutritional support was given (P < 0.01). It is suggested that nutritional support may promote synthesis of protein in COPD patients with malnutrition. Intralipid infusion would preserve nitrogen and diminish the carbohydrate metabolism and might be beneficial to correct the hypercapnea in COPD.

Cement particles inhibit bone growth into titanium chambers implanted in the rabbit

Particles of bone cement have been shown previously to stimulate the resorption of bone. The purpose of this study was to determine whether particles of bone cement (BC) have an adverse effect on bone ingrowth. The bone harvest chamber was implanted bilaterally in the proximal tibial metaphysis of 6 mature rabbits. Both the fixed outer cylinder and the inner removable core of the chamber have a transverse 1 mm wide pore providing a continuous canal for tissue ingrowth. After an initial 6-week period for osseointegration of the outer cylinder, the contents of the inner core were harvested repeatedly at 3 weekly intervals. In the first series of rabbits, the carrier solution, 1% sodium hyaluronate (Healon) was implanted first. In subsequent implantations, Healon was mixed with small fabricated particles of BC (averaging 3.54 mm in diameter) to fill the channel of the core. The contralateral chamber was left empty and served as a control. In the second series of rabbits, implantation was carried out sequentially using the same material bilaterally. The sections from the control harvests, and those with Healon alone contained extensive trabecular bone arranged longitudinally in the canal, in a fibrovascular stroma. The sections containing BC particles were infiltrated by foamy, mononuclear and multinuclear histiocytic cells. Less trabecular bone was seen in the sections containing BC particles compared to the control sections or those containing Healon alone. Previous studies have shown that particles of bone cement stimulate bone resorption. In this study, BC particles have also been shown to diminish the formation of new bone.

Putative melatonin receptors in the male guinea pig kidney

The direct action of pineal melatonin on the renal system is supported by our demonstration of 2-[125I]iodomelatonin binding sites in the male guinea pig kidney. Scatchard analyses and Hill coefficients revealed a single type of binding site with an equilibrium dissociation constant (Kd) of 22.3 +/- 1.6 pmol/l and a maximum binding density (Bmax) of 0.99 +/- 0.03 fmol/mg protein (n = 7) at mid-light. There was no significant difference in the Kd and Bmax values between kidney tissues collected at the middle of light and dark periods. The pharmacological profile of these 2-[125I]iodomelatonin binding sites indicated high specificity for melatonin, 2-iodomelatonin and 6-chloromelatonin while kinetic studies generated a Kd value of 28.4 +/- 7.3 pmol/l (n = 5) which was comparable to that determined from Scatchard transformations. Our results suggest that these binding sites are stable, reversible, saturable, specific, and of high affinity. Regional distribution study showed that specific binding of 2-[125I]iodomelatonin was 8-fold higher in the cortical region than that in the medullary region. Studies of subcellular distribution showed that 59.3% of binding sites were localized in crude nuclear fractions followed by crude mitochondrial fractions (22.3%) and crude microsomal fractions (18.3%) with no detectable binding in cytosolic fractions. Our present findings suggest the presence of putative melatonin receptors in the guinea pig kidney, which support the hypotheses of melatonin-regulated renin secretion together with renal excretory functions via melatonin receptors.

Structure of novel gangliosides, deaminated neuraminic acid (KDN)-containing glycosphingolipids, isolated from rainbow trout ovarian fluid

Two acidic glycosphingolipids were isolated and purified from rainbow trout ovarian fluid. They were designated as ovarian fluid gangliosides ofg-2a and ofg-2b. Both of these glycolipids were found to contain glucose, galactose, and N-acetylgalactosamine in a molar ratio of 1:2:1, but they differ by the presence of 2 mol of deaminated neuraminic acid (KDN; 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) in ofg-2a and 1 mol each of KDN and 9-O-acetyl-KDN in ofg-2b. On the basis of composition analysis, methylation analysis, mild acid hydrolysis, fast atom bombardment mass spectrometry (FABMS), 400-MHz 1H nuclear magnetic resonance spectroscopy, and immunochemical analysis using a monoclonal antibody (mAb.kdn3G), the complete structures of these gangliosides were determined to be KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer for ofg-2a [(KDN)GD1a] and 9-O-AcKDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer for ofg-2b [(KDN)GD1a(OAc+)]. The ceramide moieties (Cer) in both ofg-2a [(KDN)GD1a] and ofg-2b [(KDN)GD1a(OAc+)] were found by combining of the results from fatty acid analysis and FABMS measurements to be made up of 4-sphingenine and mainly a C24:1 fatty acyl chain (nervonate). The structures of ofg-2a and ofg-2b are novel, and they represent the second example of naturally occurring KDN-gangliosides. Mild acid hydrolysis of both ofg-2a and ofg-2b resulted in formation of (KDN)GM1a.

In vitro transcription of a Drosophila U1 small nuclear RNA gene requires TATA box-binding protein and two proximal cis-acting elements with stringent spacing requirements

Transcription of a Drosophila U1 small nuclear RNA gene was functionally analyzed in cell extracts derived from 0- to 12-h embryos. Two promoter elements essential for efficient initiation of transcription in vitro by RNA polymerase II were identified. The first, termed PSEA, is located between positions -41 and -61 relative to the transcription start site, is crucial for promoter activity, and is the dominant element for specifying the transcription initiation site. PSEA thus appears to be functionally homologous to the proximal sequence element of vertebrate small nuclear RNA genes. The second element, termed PSEB, is located at positions -25 to -32 and is required for an efficient level of transcription initiation because mutation of PSEB, or alteration of the spacing between PSEA and PSEB, severely reduced transcriptional activity relative to that of the wild-type promoter. Although the PSEB sequence does not have any obvious sequence similarity to a TATA box, conversion of PSEB to the canonical TATA sequence dramatically increased the efficiency of the U1 promoter and simultaneously relieved the requirement for the upstream PSEA. Despite these effects, introduction of the TATA sequence into the U1 promoter had no effect on the choice of start site or on the RNA polymerase II specificity of the promoter. Finally, evidence is presented that the TATA box-binding protein is required for transcription from the wild-type U1 promoter as well as from the TATA-containing U1 promoter.

Role of secretin in negative feedback regulation of postprandial pancreatic secretion in dogs

BACKGROUND

A negative feedback regulation of pancreatic exocrine secretion has been observed in fasting rats, pigs, and humans, but this phenomenon could not be found in fasting dogs. The aims of the present study were to investigate whether or not postprandial pancreatic secretion is regulated by a negative feedback mechanism and to determine if the mechanism is mediated by secretion and/or cholecystokinin (CCK) in dogs.

METHODS

In eight dogs prepared with gastric and Herrera's pancreatic cannulas, pancreatic juice was collected for 3 hours after feeding a mixed meal to measure volume, bicarbonate, and trypsin output. Peripheral venous blood was obtained to determine plasma immunoreactive secretin and CCK levels. Four groups of experiments were performed while pancreatic juice was diverted from the duodenum: (1) diversion of pancreatic juice alone, (2) intraduodenal infusion of fresh pancreatic juice while pancreatic juice was diverted, (3) intraduodenal infusion of 150 mg/h of trypsin and 300 mg/h of chymotrypsin, and (4) intraduodenal infusion of 0.1 mol/L NaHCO3.

RESULTS

Pancreatic secretion during diversion of pancreatic juice was significantly greater than that obtained while pancreatic juice was returned. Diversion-induced pancreatic hypersecretion was significantly suppressed by intraduodenal administration of pancreatic proteases, but it was not influenced significantly by 0.1 mol/L NaHCO3. The suppression by either pancreatic juice or proteases paralleled the decrease in plasma secretin response, whereas the CCK response remained unchanged. The inhibitory effect of pancreatic proteases on pancreatic secretion was blocked by a physiological dose of exogenous secretin, 0.06 clinical U.kg-1.h-1.

CONCLUSIONS

In dogs, postprandial pancreatic secretion is controlled by a negative feedback mechanism mediated mainly by the release of secretin, but not by CCK.

Involvement of cytokines and vascular adhesion receptors in the pathology of fronto-ethmoidal mucocoeles

Fronto-ethmoidal mucocoeles have the capacity to destroy bone. Sinus lining tissue has been obtained at surgery from patients with mucocoeles, from those with chronic sinusitis undergoing endoscopic sinus surgery and from patients undergoing craniofacial resection. Tissues have been frozen, sectioned, and subjected to immunohistochemical examination with monospecific antibodies for the presence of the potent osteolytic cytokines interleukins-1 and -6 and tumour necrosis factor alpha. In addition, the chemotactic intercrine--interleukin-8 was investigated. The presence of the cytokine-inducible vascular endothelial adhesion receptors--Inter-Cellular Adhesion Molecule (ICAM)-1 and E-Selectin (also known as Endothelial Leukocyte Adhesion Molecule--ELAM) was also determined. Normal sinus tissue showed no immunoreactivity with the antibodies to these various moieties. Surprisingly, only a small proportion of tissues from patients with chronic sinusitis showed the presence of cytokines or vascular adhesion receptors. In contrast, all specimens of fronto-ethmoidal mucocoeles showed positive staining for IL-1 alpha and beta and for ICAM-1 and E-selectin. IL-1 immunostaining was restricted to the epithelial cell population not being found in infiltrating leukocytes. In 40% of mucocoeles infiltrating macrophage-like cells showed the presence of tumour necrosis factor alpha. The presence of the potent osteolytic cytokine--IL-1 in all specimens of fronto-ethmoidal mucocoeles coupled to the finding of the IL-1-inducible adhesion molecules ICAM-1 and E-Selectin argues strongly that IL-1 is released from the epithelial cells and that this cytokine may be the factor causing the erosion of bone overlying the expanding mucocoele. The nature of the signals inducing cytokine synthesis remain, however, unidentified.

[125I]iodomelatonin binding sites in mammalian and avian kidneys

[125I]Iodomelatonin binding sites have been identified and characterized in kidneys of birds and mammals. These binding sites in the kidneys of guinea pig, duck and chicken were found to be stable, reversible, saturable, specific and of high affinity. The binding densities (Bmax) of [125I]iodomelatonin binding sites in the kidneys of guinea pig, duck and chicken ranged from 1.07 to 6.43 fmol/mg protein and the equilibrium dissociation constants (Kd) from 19.2 to 44.6 pmol/l at the middle of the light period (mid-light). It appears that [125I]iodomelatonin binding in the kidneys of mammalian species may have lower densities compared with birds. In the mammals studied, the guinea pig kidney showed the highest [125I]iodomelatonin binding. Pharmacological data indicated that the [125I]iodomelatonin binding to kidneys of guinea pig, duck and chicken was highly specific to melatonin, 2-iodomelatonin and 6-chloromelatonin. Diurnal variations in the Bmax of [125I]iodomelatonin binding sites were detected in the kidneys of duck and chicken with no difference in affinity. However, there was no diurnal variation in the Kd or Bmax in the guinea pig kidneys. The density of [125I]iodomelatonin binding sites in the cortex of guinea pig kidney was more than 8-fold higher than the binding in the medulla. Guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S; 10 mumol/l) reduced the Bmax and increased the Kd of [125I]iodomelatonin binding sites in the chicken kidney. However, in the membrane preparations of the guinea pig kidney, co-incubation with GTP gamma S (15 mumol/l) increased the Kd with no effect on the Bmax of the [125I]iodomelatonin binding. The effects of GTP gamma S on the kidney [125I]iodomelatonin binding suggest that these binding sites may couple to a G protein. The identification of [125I]iodomelatonin binding sites in the kidneys of mammals and birds supports the possibility of melatonin acting directly on the renal system.

Immunocytochemical study with anti-muscle actin antibody (HHF35) on myocardial ischaemia and reperfusion injury in rats

Myocardial ischaemia and reperfusion injury in 16 anaesthetized Sprague-Dawley rats, eight of which were pretreated with morphine (5 mg/kg, intraperitoneally) to prevent arrhythmias, were studied immunocytochemically with anti-muscle actin specific monoclonal antibody (HHF35). Eight cases of simple ischaemia and eight cases of sham-operated rats were used as controls. With HHF35 ABC immunocytochemical method, the left ventricular myocardium in the reperfusion group (without morphine) showed large areas of staining loss, but no loss of staining was seen in controls. No significant changes were seen with H&E stain in all hearts. Compared with HBFP, acridine orange (AO), eosin-fluorescence, HHF35 ABC staining best demonstrated myocardial reperfusion injury. The results indicate that the degree of myocardial damage may be related to the arrhythmias.

Ionic channel currents in cultured neurons from human cortex

Ionic channels in human cortical neurons have not been studied extensively. HCN-1 and HCN-1A cells, which recently were established as continuous cultures from human cortical tissue, have been shown by histochemical and immunochemical methods to exhibit a neuronal phenotype, but expression of functional ionic channels was not demonstrated. For the present study, HCN-1 and HCN-1A cells were cultured in Dulbecco's modified Eagle's medium with 15% fetal calf serum, in some cases supplemented with 10 ng/ml nerve growth factor, 10 microM forskolin, and 1 mM dibutyryl cyclic adenosine monophosphate to promote differentiation. Cells or membrane patches were voltage clamped using conventional patch clamp techniques. In HCN-1A cells, we identified a tetrodotoxin-sensitive Na+ current, two types of Ca2+ channel current, including L-type current and a second type that in some respects resembled N-type current, and four types of K+ current, including a delayed outward rectifier that showed voltage-dependent inactivation, two types of noninactivating Ca(2+)-activated K+ channels with slope conductances of 146 and 23 pS (K+i/K+o 145 mM/5 mM), and less frequently, a noninactivating, intermediate conductance channel that was not sensitive to internal Ca2+. When HCN-1A cells were examined after 3 days of exposure to differentiating agents, pronounced morphological changes were evident but no differences in ionic currents were apparent. HCN-1 cells also exhibited K+ and Ca2+ channel currents, but Na+ currents were not detected in these cells.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pre-and postoperative indocyanine green retention rate as a marker of liver functional reserve in cirrhotic patients]

Indocyanine green ICG retention rate was determined before and after in portohypertensive cirrhotic patients undergoing paracardial devascularization (PCDV) and side-to-side mesocaval shunt (MCs-ss). The relationship between ICG retention rate with serum albumin level and the incidence of ascites was investigated no significant change the rate was noted before and after. Operation in PCDV patients. Significant increase of the rate was observed after MCs-ss. There was a negative correlation between the rate and serum albumin level. Addition the incidence of ascites increased with the elevation of the rate, there was a significant difference in the rate in patients with or without ascites.

Characterization of a virG mutation that confers constitutive virulence gene expression in Agrobacterium

Transformation of plants by Agrobacterium tumefaciens is mediated by a set of virulence (vir) genes that are specifically induced by plant signal molecules through the VirA/VirG two-component regulatory system. The plant signal is transmitted from VirA to VirG by a cascade of phosphorylation reactions followed by the sequence-specific DNA binding of the VirG protein to the vir gene promoters which then activates their transcription. In this report, we describe a VirG mutant which is able to activate vir gene expression independently of the VirA molecule and the two plant signal molecules, acetosyringone and monosaccharides. A strain of Agrobacterium containing this virG gene but lacking a functional virA gene was able to induce tumours on all three plants that were tested. A single amino acid change of asparagine (N) to aspartate (D) at position 54, adjacent to the site of VirG phosphorylation, aspartate 52, resulted in this constitutive phenotype. In vitro phosphorylation experiments showed that the mutant protein cannot be phosphorylated by VirA, suggesting that the negative charge resulting from the N to D switch mimics the phosphorylated conformation of the VirG molecule. The same amino acid change in the virG gene of the supervirulent strain A281 also resulted in a constitutive phenotype. However, the vir genes were not induced to high levels when compared with the levels of the constitutive virG of strain A348.

Monoclonal antibody specific to alpha-2-->3-linked deaminated neuraminyl beta-galactosyl sequence

Fusion of spleen cells from a BALB/c mouse immunized with KDN alpha 2-->3Gal beta 1-->4Glc beta 1-->1Cer ((KDN)GM3) with P3-X63 Ag8.U1 (P3U1) mouse myeloma cells yielded a hybrid cell line that produced monoclonal antibody that bound to (KDN)GM3, but not to Neu5Ac alpha 2-->3Gal beta 1-->4Glc-beta 1-->1Cer ((Neu5Ac)GM3). The specificity of the monoclonal antibody was determined chiefly by the enzyme-linked immunosorbent assay procedure. This antibody was found to react most strongly with (KDN)GM3 and less strongly with a glycoprotein containing a number of KDN alpha 2-->3Gal beta 1-->3-GalNAc alpha 1-->3[8KDN alpha 2-->)n-->6]GalNAc alpha 1-->chains (< n > av = approximately 3). The results indicated that the monoclonal antibody (designated mAb.kdn3G) specifically and effectively recognized a disaccharide structure, KDN alpha 2-->3Gal beta 1-->, and specifically discriminated (KDN)GM3 from (Neu5Ac)GM3. The mAb.kdn3G was used to localize (KDN)GM3 in rainbow trout sperm by the indirect immunofluorescence procedure and the antigen was shown to be mostly, if not completely, associated with the external surface of the entire plasma membrane of rainbow trout sperm. The potential utility of mAb.kdn3G is addressed in searching for KDN-glycoconjugates which contain glycan units having the KDN alpha 2-->3Gal beta 1-->epitope structure.

Pharmacokinetic characteristics and antitumor activity of the N-succinyl-chitosan-mitomycin C conjugate and the carboxymethyl-chitin-mitomycin C conjugate

The conjugate between N-succinyl-chitosan (Suc-chitosan) and mitomycin C (MMC), named Suc-chitosan-MMC, and that between carboxymethyl-chitin (CM-chitin) and MMC, named CM-chitin-MMC, were investigated in vivo. As for the intraperitoneal drug administration using rats, the order of the maximum blood concentration of MMC was unconjugated MMC > CM-chitin-MMC > Suc-chitosan-MMC. The plasma concentration of MMC for Suc-chitosan-MMC was maintained at an almost constant level over 24 h. Pharmacokinetic analysis of each plasma concentration indicated that for each conjugate, the in vitro drug release reported previously was useful for the approximate estimation of the in vivo regeneration of MMC. The chemotherapeutic effect of MMC and the conjugates was investigated using mice bearing L1210 leukemia or B16 melanoma. Concerning antitumor activity against L1210 leukemia, the conjugates exhibited a marked effect at higher doses, and their effect increased even in the dose range where the effect of MMC decreased. MMC and the conjugates exhibited a good growth-inhibitory effect against B16 melanoma. Complete inhibition of growth of B16 melanoma was observed at the dose of 10 mg eq MMC/kg for CM-chitin-MMC.

Effects of guanosine 5'-O-(3-thiotriphosphate) on 2-[125I]iodomelatonin binding in the chicken lung, brain and kidney: hypothesis of different subtypes of high affinity melatonin receptors

Effects of 10 mumol/l guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), a non-hydrolyzable analog of guanosine 5'-triphosphate, on 2-[125I]iodomelatonin binding were investigated. In the chicken lung, 10 mumol/l GTP gamma S significantly increased (p < 0.05) the equilibrium dissociation constant (Kd) values, but did not affect the maximum number of binding sites (Bmax). Conversely, in the chicken brain, GTP gamma S significantly depressed (p < 0.05) the Bmax, but did not change the Kd of the 2-[125I]iodomelatonin binding sites in the brain tissue. A third variation was observed in the chicken kidney with GTP gamma S altering (p < 0.05) both the Kd and the Bmax of 2-[125I]iodomelatonin binding sites. The reason underlying the different effects of GTP gamma S on 2-[125I]iodomelatonin binding in the tissue preparations is not clear. However, we would like to hypothesize that they may represent distinct subtypes of the ML-1-type melatonin receptor with different receptor-G-proteins-effector complex. The group represented by the 2-[125I]iodomelatonin binding sites found in the chicken lung, which is downregulated by GTP gamma S with a consequent increase in the Kd value, has been designated ML-1 alpha. The second group, exemplified by the brain 2-[125I]iodomelatonin binding sites, which respond to GTP gamma S with a change in Bmax, has been labelled ML-1 beta. The third group, characterized by GTP gamma S-mediated alterations in both Bmax and Kd and found in the chicken kidney, has been called ML-1 gamma. Different subtypes of melatonin receptors may address the issue of the different physiological actions of melatonin reported in individual tissues within the same species or similar tissues but different species. Specialized responses could be generated depending on the predominant subtype of ML-1 receptors associated with the target tissue.

[The nutritional status and immune function of patients with chronic obstructive pulmonary disease]

The nutritional status and immune function of 14 patients with exacerbation of chronic obstructive pulmonary disease (COPD) were assessed and were studied again one week after the patients had recovered. The results showed that the nutritional status of the patients was poorer on admission, the level of some kinds of serum free amino acid was significantly lower than the normal value, the value of branch-chain amino acid (BCAA) was significantly lower than that in healthy people (P < 0.01), but the level of aromatic amino acid (AAA) was higher than the normal value. Level of serum free fatty acid was significantly lower during admission and in recovery period (P < 0.01). It is suggested that shortage of essential fatty acid in the patients is obvious. The results also showed that the patients identified as malnourished had a lower cellular immune function, but the humoral immune function was not significant between the patients group and control group. Immune function was improved with the recovery nutritional status of the patients. The results suggest that malnutrition and hypoimmunity may play a very important role in the pathogenesis of COPD.

Selective A2-adenosine receptor agonists do not alter action potential duration, twitch shortening, or cAMP accumulation in guinea pig, rat, or rabbit isolated ventricular myocytes

In this study, the hypothesis that mammalian ventricular myocytes possess A2-adenosine receptors was tested. Electrophysiological, contractile, and cAMP responses to the selective A2-adenosine receptor agonists 2-[2-(4-methylphenyl)ethoxy]adenosine (WRC-0090) and 2-(2-cyclohexylethoxy)adenosine (WRC-0013) and the nonselective adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine (NECA) were measured using ventricular myocytes isolated from guinea pig, rabbit, and rat hearts. Pertussis toxin pretreatment and/or the selective A1-adenosine receptor antagonists 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) and (+/-)N6-endonorbornan-2-yl-9-methyladenine (N-0861) were used to prevent activation of A1-adenosine receptors in these cells. Action potential duration at 50% repolarization was not altered by WRC-0090, NECA, or WRC-0013 with or without 0.1 microM DPCPX or pertussis toxin pretreatment, and WRC-0090 and NECA failed to prolong the action potential duration of myocytes exposed to 0.1 or 1 microM forskolin. WRC-0090 alone or with 0.1 microM DPCPX did not increase the amplitude of shortening of pertussis toxin-treated or untreated myocytes, and WRC-0090 or NECA did not significantly increase cAMP accumulation. In contrast to these results with myocytes, in the smooth muscle cell line DDT1MF-2 the effect of both selective A2-agonists on cAMP accumulation was biphasic: low concentrations (< or = 0.3 microM) increased but higher concentrations decreased accumulation of cAMP. The decreased cAMP accumulation seen at higher agonist concentrations was completely abolished by either 0.1 microM DPCPX or pretreatment of cells with pertussis toxin. In summary, the results of the present study do not provide evidence for A2-adenosine receptors on mammalian ventricular cardiomyocytes but confirm reports of the coexistence of both A1 and A2 subtypes of adenosine receptors on DDT1MF-2 cells.

The identification and characterization of 125I-labelled iodomelatonin-binding sites in the duck kidney

The melatonin-binding sites in membrane preparations of duck kidney were demonstrated by utilizing 125I-labelled iodomelatonin as a radioligand. Binding at these sites was found to be reversible, saturable, specific and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium binding constant (Kd) of 44.6 +/- 4.4 pmol/l (n = 6) and a total number of binding sites (Bmax) of 6.43 +/- 0.60 fmol/mg protein (n = 6) at the mid-point of the light period (mid-light). The Hill coefficient approached 1.0, suggesting a single class of 125I-labelled iodomelatonin-binding site in the duck kidney. Diurnal variation in 125I-labelled iodomelatonin binding showed that the Bmax was 53.4% higher at mid-light than at mid-point of the dark period (P < 0.05), with no significant variation in Kd. The Kd value determined from kinetic analysis was 22.5 pmol/l in birds at mid-light, which was comparable with values determined from equilibrium studies. The order of pharmacological affinity for 125I-labelled iodomelatonin-binding sites in the duck kidney membrane preparations was: 2-iodomelatonin > melatonin > 6-chloromelatonin > 6-hydroxymelatonin > N-acetylserotonin >> 5-methoxytryptamine, 5-methoxytryptophol, 5-hydroxytryptamine, tryptamine, 1-acetylindole-3-carboxaldehyde, 5-hydroxyindole-3-acetic acid, L-tryptophan, 5-methoxyindole-3-acetic acid, 3-acetylindole, acetylcholine, epinephrine, norepinephrine and harmaline. The pharmacological characteristics indicated that 125I-labelled iodomelatonin-binding sites are highly specific for melatonin. Our finding of 125I-labelled iodomelatonin-binding sites in the kidney suggests that melatonin may regulate kidney function.(ABSTRACT TRUNCATED AT 250 WORDS)

[125I]iodomelatonin-binding sites in the chicken kidney: characterization and comparison to other avian species

The existence of [125I]iodomelatonin-binding sites in the kidney of the chicken and other avian species has been demonstrated in the present study. [125I]Iodomelatonin-binding sites in membrane preparations of the chicken kidney were reversible, saturable, specific and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium binding constant (Kd) of 30.3 +/- 5.1 pmol/l (n = 5) and a total number of binding sites (Bmax) of 2.89 +/- 0.24 fmol/mg protein (n = 5) at the middle of the light period (mid-light). The Hill coefficient approached 1.0, suggesting a single class of [125I]iodomelatonin-binding sites in the chicken kidney. The diurnal variation study showed that the Bmax was 52% higher at mid-light than that in the middle of dark period (1.90 +/- 0.33 fmol/mg protein, n = 4; p < 0.05), with no significant variation in Kd. The Kd value determined from kinetic analysis was 10.8 pmol/l in the mid-light birds, which was comparable to values determined from equilibrium studies. The competition inhibitor experiments demonstrated that [125I]iodomelatonin-binding sites were highly specific for melatonin with the following order of potency: 2-iodomelatonin > melatonin, 6-chloromelatonin > 6-hydroxymelatonin N-acetylserotonin >> 5-methoxytryptamine, 5-methoxytryptophol, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptamine, 1-acetylindole-3-carboxaldehyde, 3-acetylindole, tryptamine, 5-methoxyindole-3-acetic acid, L-tryptophan, harmaline, acetylcholine, epinephrine and norepinephrine. Studies on the relative binding density of [125I]iodomelatonin to the kidney in different species of birds showed the following descending order: duck > chicken > pigeon > quail.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced self-pumped phase conjugation from 16 degrees -cut KNSBN:Cu

With the maximum coupling coefficient and high internal reflection conditions, the self-pumped phase-conjugation reflectivity of copper-doped potassium sodium strontium barium niobate (KNSBN:Cu) is increased with 16 degrees -cut samples. The response time is also shortened. The resolution property of 16 degrees -cut KNSBN:Cu is determined and a distorted image is corrected by using the 16 degrees -cut sample.