[Treatment and prognosis of stage II testicular seminoma]

Sixty-five patients with stage II testicular seminoma treated from 1960 through 1990 were reviewed. According to Royal Marsden Hospital staging, there were 11 stage IIA, 13 stage IIB, and 41 stage IIC. Thirty Patients were treated with combination of radiotherapy and chemotherapy, 11 chemotherapy alone, 24 rediotherapy alone. The overall 5-year survival rate was 75.6%, with 100% for stage IIA, 92.3% for stage IIB and 62.9% for stage IIC. The differences were statistically significant. In stage IIC patients, there was no significant difference between those tumors > 10cm and < 10cm in diameter. Of the 41 IIC cases, 4 were treated with chemotherapy, 15 were treated with whole abdominal rediation, 22 with paraaortic and ipsilateral pelvic radiation. The 5-year survival rate was 91.7% and 51.2%, respectively. These differences was statistically significant. We recommand that stage IIC disease should be treated primarily with whole abdominal radiation. Regardless of the stage of the disease, prophylactic mediastinal irradiation did not influence the survival nor the relapse rate and may therefore be omitted.

An evaluation of numerical integration algorithms for the estimation of the area under the curve (AUC) in pharmacokinetic studies

Six numerical integration algorithms based on linear and log trapezoidal methods as well as four cubic-spline methods were proposed for estimation of area under the curve (AUC). These six different algorithms were implemented using IMSL/IDL command language and evaluated using data simulated under five different dosing conditions and two different sampling conditions. Comparisons between AUC estimations using these six different algorithms and the theoretical results were made in terms of both overall AUC values and the superimposability of the concentration-time profiles. In well designed studies with ample data points, the algorithm based on IMSL/IDL function CSSHAPE with concavity preservation gave the best performance. In contrast, when the frequency of blood collection was limited, the algorithm based on the log trapezoidal rule proved to be stable with reasonable accuracy, and is recommended as the practical method for numerical interpolation and integration in pharmacokinetic studies. Algorithms based on the combination of the log trapezoidal rule and cubic-spline methods using IMSL/IDL function CSSHAPE can be developed to enhance overall performance.

Induction of protective immunity against herpes simplex virus with DNA encoding the immediate early protein ICP 27

Using a mouse zosteriform model that mimics human herpes simplex virus (HSV) infection in several aspects, the effectiveness of plasmid DNA encoding the immediate early protein ICP 27 was evaluated as a vaccine. Animals were immunized intramuscularly twice with DNA, then either challenged with virus or killed, and the nature of the immune response induced was measured. After intramuscular injection with plasmid DNA encoding ICP 27 (pc-ICP 27), solid protection was evident in 70-80% of mice and the lesions were delayed in the remaining animals. Immune splenocytes obtained from pc-ICP 27 immune mice showed HSV-specific lymphoproliferation, MHC-class I restricted cytotoxic T-lymphocyte (CTL) activity, and type 1 cytokine production. These animals also exhibited delayed-type hypersensitivity (DTH) reactions. Adoptive transfer studies conducted on syngeneic nude mice revealed that those recipients of immune CD4+ T cells, but not CD8+ T cells, were protected from subsequent HSV-1 (strain 17) challenge. Thus pc-ICP 27 DNA immunization protected the mice principally by CD4+ T cells and it is likely that these cells were Th-1 type because only type 1 cytokines were detectable after in vitro antigen stimulation. Our results indicate the potential value of DNA encoding nonstructural viral proteins as vaccines against HSV.

Effect of current magnitude and drug concentration on iontophoretic delivery of octreotide acetate (Sandostatin) in the rabbit

The effect of current magnitude and drug concentration on transdermal iontophoretic delivery of octreotide acetate (Sandostatin) was examined in the rabbit. Plasma samples were collected over 24 hours and octreotide concentrations were determined by a radioimmunoassay. Without an electrical current, negligible plasma concentrations of octreotide were obtained. Following initiation of iontophoresis, plasma concentrations of octreotide increased rapidly, although did not sustain at a plateau level during the dosing period. Octreotide concentrations declined rapidly after removal of the device. Increasing the electrical current from 50 microA/cm2 to 150 microA/cm2 yielded a proportional increase in the delivery. Increasing the drug concentration in the device from 2.5 mg/mL to 5 mg/mL resulted in approximately proportional increase in plasma octreotide concentrations; however, further increase in plasma concentrations was not observed for drug concentrations beyond 5 mg/mL. Iontophoretic delivery at the conditions which yielded the highest octreotide concentrations in this study (5 mg/mL solution at 150 microA/cm2 for 8 hours) yielded an apparent bioavailability (which represents an underestimate of the absolute bioavailability determined when the patches are run to exhaustion) of approximately 8%.

Lysis of porcine trophoblast cells by endometrial natural killer-like effector cells in vitro does not require interleukin-2

Cells with cytotoxic activity against the cell line K562 and expressing perforin have been demonstrated in endometrial cells isolated from pigs early in pregnancy. This study was designed to determine whether porcine trophoblast cells were susceptible to these endometrial effector cells in vitro. Pregnant gilts (n = 8) were slaughtered between Days 17 and 20 of gestation. Immediately after slaughter, both the endometrial effector cells and trophoblast cells were isolated enzymatically from each animal. Enzymatically dispersed endometrial cells were further fractionated by size at unit gravity, whereas trophoblast cells were enriched by discontinuous density centrifugation on Percoll. Cytolytic activity was evaluated against Na2 51CrO4-labeled trophoblast and K562 cells. Comparison was made between freshly prepared and interleukin-2 (IL-2)-stimulated effector cells. The effect of prostaglandin E2 (PGE2) was tested by including it directly in the 51Cr-release assay. The results indicated that porcine trophoblast cells, like K562 cells, could be recognized and directly lysed by endometrial effector cells. Preculture of effector cells with IL-2 was not required for target lysis but enhanced their cytolytic activity against both trophoblast and K562 targets. In contrast, PGE2 exhibited highly suppressive effects on the cytotoxic activity of both freshly isolated and IL-2-stimulated endometrial effector cells. Conjugate assays demonstrated the binding of trophoblast and K562 targets by effector cells of similar morphology. Cold-target inhibition assays suggested that the effectors in porcine endometrial cell preparations that killed trophoblast and K562 cells were the same NK cell-like population.

Saturated molecular map of the rice genome based on an interspecific backcross population

A molecular map has been constructed for the rice genome comprised of 726 markers (mainly restriction fragment length polymorphisms; RFLPs). The mapping population was derived from a backcross between cultivated rice, Oryza sativa, and its wild African relative, Oryza longistaminata. The very high level of polymorphism between these species, combined with the use of polymerase chain reaction-amplified cDNA libraries, contributed to mapping efficiency. A subset of the probes used in this study was previously used to construct an RFLP map derived from an inter subspecific cross, providing a basis for comparison of the two maps and of the relative mapping efficiencies in the two crosses. In addition to the previously described PstI genomic rice library, three cDNA libraries from rice (Oryza), oat (Avena) and barley (Hordeum) were used in this mapping project. Levels of polymorphism detected by each and the frequency of identifying heterologous sequences for use in rice mapping are discussed. Though strong reproductive barriers isolate O. sativa from O. longistaminata, the percentage of markers showing distorted segregation in this backcross population was not significantly different than that observed in an intraspecific F2 population previously used for mapping. The map contains 1491 cM with an average interval size of 4.0 cM on the framework map, and 2.0 cM overall. A total of 238 markers from the previously described PstI genomic rice library, 250 markers from a cDNA library of rice (Oryza), 112 cDNA markers from oat (Avena), and 20 cDNA markers from a barley (Hordeum) library, two genomic clones from maize (Zea), 11 microsatellite markers, three telomere markers, eleven isozymes, 26 cloned genes, six RAPD, and 47 mutant phenotypes were used in this mapping project. Applications of a molecular map for plant improvement are discussed.

Pharmacokinetics of intranasally-administered dihydroergotamine in the rat

Intranasal dosing of dihydroergotamine (DHE) allows convenient self-administration and provides an alternate route of administration for the treatment of migraine in addition to the existing parenteral dosage forms. In this study, the pharmacokinetics of 3H-DHE were investigated following intravenous and intranasal dosing (0.343 mg DHE/animal) in the rat. Intranasal administration of DHE resulted in rapid absorption. The extent of absorption of the radiolabeled dose was approximately 45%-60%. Absolute bioavailability of the parent drug was 35%-40%, as determined by deconvolution and by the ratios of AUC0-infinity following intranasal and intravenous dosing. Due to the limited capacity of the nostrils, approximately half of the intranasal dose was swallowed into the gastrointestinal tract. Biliary excretion was found to be the predominant pathway of radioactivity excretion following both routes of administration. The results from this study suggest that intranasal administration provides a viable means of delivering DHE into the systemic circulation.

Luting cement-metal surface physicochemical interactions on film thickness

Low film thickness is critical to the clinical success of cemented castings. This study investigated the effect of luting agent-metal physico-chemical surface interactions on film thicknesses of representative luting agents. Control group luting agents were placed between two glass plates, as described by American Dental Association specifications 8, 61, and 66, and test group luting agents were positioned between glass and metal plates. The materials selected were zinc phosphate cement, polycarboxylate cement, glass ionomer cement, glass ionomer-composite resin hybrid cement and a resinous cement, with a type III gold alloy, a noble metal ceramic alloy, and a base metal ceramic alloy. A two-way analysis of variance and follow-up tests were done. The effects of the type of metal surface, type of cement, and their statistical interaction significantly affected film thickness (p < 0.0001). The type of cement had a greater affect on film thickness than the type of metal. A glass ionomer cement produced lower overall film thicknesses than other cement types, and a noble metal ceramic alloy created lower overall film thicknesses than other types of metal. American Dental Association specifications for cement film thickness did not accurately reflect normal cement use.

Diminished luminal release of esophageal epidermal growth factor in patients with reflux esophagitis

OBJECTIVES

It has recently been demonstrated that human esophageal mucosa, containing numerous submucosal mucous glands, has the ability to elaborate significant amounts of esophageal epidermal growth factor (eEGF). Because of its role in the maintenance of the integrity of the esophageal mucosa, we elected to study the rate of secretion of eEGF in patients with reflux esophagitis (RE), compared with controls, using our newly developed esophageal perfusion model.

METHODS

Fourteen healthy asymptomatic volunteers and 14 patients with endoscopically confirmed esophagitis underwent esophageal perfusion with saline, HCl (0.01 M, pH 2.1) HCl/pepsin (0.5 mg/ml of HCl), and ending NaCl solution during four consecutive 8-min perfusion periods. All perfusates were assayed for EGF by RIA (Amersham). Results are expressed as mean +/- SEM. Student's t test was used for statistical analysis.

RESULTS

The basal rate of luminal EGF release in patients with RE was 3.78 +/- 0.29 ng/min. This value significantly declined (2.27 +/- 0.27 ng/min; p < 0.001) during mucosal exposure to HCl but was significantly enhanced when the HCl perfusing solution was supplemented with pepsin (4.20 +/- 0.29; p < 0.001 vs. HCl). Introduction of saline during the last perfusion period maintained a rate of luminal EGF release similar to that observed during the initial esophageal perfusion with saline. Luminal release of EGF in patients with RE was significantly lower, compared with corresponding values recorded in controls during perfusion with saline (3.78 +/- 0.29 vs. 14.1 +/- 1.25 ng/min; p < 0.00001), with HCl (2.27 +/- 0.27 vs. 5.95 ng/min; p < 0.0001), with HCl/pepsin solution (4.2 +/- 0.29 vs. 11.7 +/- 1.88 ng/min; p < 0.0001), and during the final perfusion period with saline (3.73 +/- 0.25 vs. 15.1 +/- 1.1 ng/min; p < 0.00001). Therefore, the rate of luminal EGF release in controls was 4-fold, 3-fold, 3-fold, and 4-fold higher than that of patients with RE during perfusion with initial saline, HCl, HCl/pepsin and final saline, respectively.

CONCLUSIONS

1) Decreased esophageal EGF in patients with RE may facilitate the development or delay the healing of mucosal injury. 2) Depletion of EGF from the mucus layer covering the epithelium under the impact of refluxed luminal acid/pepsin may be considered as one of the potential underlying mechanisms leading to damage of the esophageal mucosa during gastroesophageal reflux episodes.

Depressed [Ca2+]i responses to isoproterenol and cAMP in isolated cardiomyocytes from experimental diabetic rats

Experimentally, diabetic rat hearts are characterized by diminished responses to beta-adrenergic stimulation. Among the aberrant responses are diminished beta-adrenoceptor number and depressed contractile protein activity. In this study, intracellular Ca2+ concentration ([Ca2+]i) was determined by microfluorescence in response to beta-adrenergic stimulation to understand the basis for the changes in the beta-adrenergic pathway in diabetic myocardium. In quiescent myocytes, isoproterenol caused a decrease in [Ca2+]i, which was blocked by timolol and thapsigargin. This suggests that the beta-agonist-induced [Ca2+]i changes are mediated, in part, by sarcoplasmic reticulum Ca-adenosinetriphosphatase. Diabetic myocytes showed a blunted response to isoproterenol, which was reversed by insulin treatment. In electrically stimulated myocytes, isoproterenol and 8-bromo-adenosine 3',5'-cyclic monophosphate (cAMP) increased [Ca2+]i and contraction in a concentration-dependent manner. Electrically stimulated diabetic myocytes demonstrated a depressed maximum [Ca2+]i response to isoproterenol and 8-bromo-cAMP without a change in sensitivity. These data suggest that in addition to alterations in beta-adrenoceptor function there are postreceptor defects in diabetic myocardium that may impair the regulation of [Ca2+]i in diabetic myocardium.

An ultra-sensitive electrochemical enzyme immunoassay for thyroid stimulating hormone in human serum

A sensitive heterogeneous electrochemical enzyme immunoassay has been developed for thyroid stimulating hormone (TSH) by modifying a commercially available two-site immunoenzymometric assay. p-Aminophenyl phosphate (PAPP) was used as the substrate of alkaline phosphatase, and hydrolysed to p-aminophenol (PAP). The amount of PAP produced from the assay was proportional to the amount of TSH in the sample. Detection of PAP was done by oxidative amperometry in a flow injection system. The working electrode was a glassy carbon electrode whose potential was held at +325 mV (vs Ag/AgCl). The amperometric detection of PAP required only 1 microliter of sample (the range of linearity: 50.0 fmol-100 pmol PAP, the limit of detection: 10.9 fmol PAP). Intra-assay precision over the assay range of linearity (0.02-60 mIU l-1 or 0.02-60 pIU TSH) showed a maximum RSD of 8.0%, and a low detection limit of 0.01 mIU l-1 or 0.01 pIU TSH. The study also indicates that this two-site electrochemical enzyme immunoassay correlates well with the Bio-Rad's immunoradiometric assay currently used in our medical center (r = 0.992, slope = 1.53, n = 43) and a highly sensitive immunochemiluminometric assay in the Nichols Institute (r = 0.986, slope = 0.499, n = 23).

Cellular functions of diabetic cardiomyocytes: contractility, rapid-cooling contracture, and ryanodine binding

To study the mechanisms of cardiac dysfunction in experimental diabetes, adult rat cardiomyocyte shortening (measured with a video edge-detector system), the sarcoplasmic reticulum (SR) Ca2+ content [assessed by rapid-cooling contracture (RCC) and caffeine contracture (CC)] was examined. Ryanodine binding to the SR Ca(2+)-release channel of myocardium homogenate was also studied. Myocytes from diabetic rats showed depressed shortening (44% decrease compared with controls), reduced maximum rates of shortening and relengthening (58 and 56% decrease, respectively), and prolonged time to peak shortening (47% increase). RCCs and CCs from diabetic cells were 68 and 75% of the control values, respectively. Most of these cardiomyocyte abnormalities were corrected by daily insulin treatment in the diabetic rats. Ryanodine binding parameters indicated that the number of high-affinity binding sites was decreased in diabetic hearts. These data suggest that changes in contractile parameters as measured in diabetic myocytes are in good agreement with data obtained from intact heart or cardiac tissue preparations. Decreased SR Ca2+ content and reduced ryanodine binding sites indicate that the SR functions of storage and release of Ca2+ were depressed. This consequently may cause depressed contraction in diabetic hearts.

Pharmacokinetics of SDZ 64-412, a novel antiasthmatic agent, following intravenous, oral, and inhalation dosing in the rat

The pharmacokinetics of SDZ 64-412, an antiasthmatic agent, were investigated following intravenous, oral, and inhalation dosing in rats. 14C-SDZ 64-412 was administered intravenously (2.75 mg kg-1) and orally (5.5 mg kg-1, 110 mg kg-1), whereas non-radiolabeled drug (5.04 mg kg-1) was administered using nose-only inhalation chambers. Radioactivity and parent drug concentrations in blood, lung, and excreta were determined at designated times post-dose. SDZ 64-412 was rapidly and extensively (approximately 80%) absorbed following both oral doses, although absorption appeared to be prolonged with increasing dose. The absorbed drug was shown to undergo extensive and saturable first-pass metabolism. The bioavailability of the parent drug, calculated by dose-normalized AUC and deconvolution methods, was only 10-15% from the low dose, but increased to approximately 40% following the high dose. Following inhalation dosing, SDZ 64-412 concentrations in blood and lungs increased rapidly, and did not decline immediately after termination of dosing. The inhalation dose yielded a bioavailability of approximately 40%, and AUC of the drug in lungs was approximately 25 times greater than in blood. In general, SDZ 64-412 was extensively distributed and rapidly eliminated from the systemic circulation. Biliary excretion was the predominant route of radioactivity excretion. The present findings suggest that inhalation administration provides a viable means of delivery of SDZ 64-412.

In vitro characterization of nonpeptide irreversible inhibitors of HIV proteases

The irreversible inhibition of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) proteases by 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) and eight haloperidol derivatives has been studied. EPNP specifically inhibits HIV-1 and HIV-2 proteases with a stoichiometry of one EPNP molecule/dimeric enzyme. The site of modification of HIV-2 protease by EPNP has been unambiguously identified as Asp-25 using high performance tandem mass spectrometry. The haloperidol derivatives assayed consist of epoxides, ynones, and alpha,beta-unsaturated ketones. The Kinact values for these haloperidol derivatives range from 10.7 to 521 microM for HIV-1 protease and from 8.6 to 283 microM for the HIV-2 enzyme, being in some cases approximately 1000-fold more potent irreverisble inhibitors of HIV proteases than EPNP. This potency results from the haloperidol character of the compounds and the chemical reactivity of the groups capable of forming a covalent bond with the enzyme. Covalent modification of HIV-2 protease by a radiolabeled epoxide derivative of haloperidol, UCSF 84, is prevented by EPNP and the peptidomimetic transition state analog U-85548. In similar experiments, incorporation of UCSF 84 into HIV-1 protease is partially prevented by these active-site inhibitors. In contrast, a mutant HIV-1 protease, HIV-1 PR C95M, in which Cys-95 has been replaced by Met, is labeled 50% less than HIV-1 protease and is fully protected by EPNP and U-85548. These results indicate the presence of 2 reactive residues in HIV-1 protease: Cys-95 and another located in the active site of the enzyme. The alpha,beta-unsaturated ketone derivative of haloperidol, UCSF 191, which is stable over a broad pH range, was used to study the pH profile of inactivation of HIV-1 and HIV-2 proteases. Comparison of the profiles of inactivation of wild-type HIV-1 protease, HIV-1 PR C95M, and HIV-1 PR C67L as well as HIV-2 protease (which has no cysteine residues) reveals the contribution of Cys-95 to the reactivity of these irreversible inhibitors. The inhibitors UCSF 70, UCSF 84, UCSF 115, UCSF 142, and UCSF 191 reduce p55gag polyprotein processing when assayed in a mammalian cell line that produces HIV-1 viral particles lacking the envelope.

Impact of acid and pepsin on human esophageal prostaglandins

OBJECTIVES

Although the prostaglandin-mediated mucosal protection within the gastric compartment has been well established, its potential role in the maintenance of integrity of the esophageal mucosa in humans has not been explored due to the lack of appropriate methodology.

METHODS

We have recently developed an esophageal perfusion catheter, equipped with two balloons, compartmentalizing a 7.5-cm segment of the esophageal lumen. Using this catheter, we studied the impact of the luminal perfusion with saline, HCl (0.01 M, pH 2.1), and HCl/pepsin solutions (0.5 mg/ml) on esophageal luminal release of PGE2 in 21 asymptomatic, presumably healthy volunteers (12 M, 9F; mean age 40 yr). The content of PGE2 in its methyl oximated form was measured by RIA (Amersham, IL), using a novel iodinated label. Results are expressed as mean +/- SEM. Student's t test was used for statistical analysis.

RESULTS

Perfusion of the esophageal lumen resulted in continuous release of PGE2 into the perfusate at the rate of 1880 +/- 393 pg/min during the first 8-min perfusion period. During continuation of perfusion with saline, the luminal release of PGE2 was maintained at the rate of 1820 +/- 640 pg/min during the second 8-min perfusion period. This rate declined (although in nonsignificant fashion; p < 0.2) during the third perfusion period, reaching a plateau of 1220 +/- 473 pg/min and maintained during the last (period IV) perfusion period with saline. Introduction of acid during the perfusion period II in the second group of investigated subjects resulted in a rapid and statistically significant decline of the luminal release of PGE2 to the value of 1020 +/- 167 ng/min (p < 0.01). Continuation of esophageal perfusion with acid during the next 8-min perfusion period further diminished the luminal release of PGE2 to the value of 520 +/- 73; p < 0.001. The significant decline in the rate of luminal PGE2 release was still maintained despite the replacement of acid with saline during the ending 8-min perfusion (period IV; 560 +/- 80 ng/min; p < 0.001). Esophageal perfusion with HCl/pepsin solution, in group III subjects, potentiated luminal release of PGE2, reaching the value of 1553 +/- 340 pg/min, which is 3 times higher than the value of PGE2 observed during corresponding perfusion with HCl (period III; p < 0.03). This significant impact of HCl/pepsin solution was still maintained despite the substitution of HCl/pepsin with NaCl during the last perfusion period, and was still significantly higher (1260 +/- 220 pg/min; p < 0.02) than the corresponding value during the ending perfusion with NaCl after HCl (group II). This study for the first time demonstrates that luminal release of PGE2 in humans remains under a significant impact of luminal chemical factors such as acid and pepsin.

CONCLUSION

The modulatory effect of acid and pepsin on esophageal mucosal prostaglandin release may play a role in the development of reflux-related mucosal pathology.

In vivo microleakage of luting cements for cast crowns

Standardized tooth preparations were completed on previously intact human molars in vivo, and castings were made with a precious metal ceramic alloy by conventional techniques. The castings were randomly assigned to the following luting agents: zinc phosphate, composite resin-glass ionomer hybrid, and a composite resin-glass ionomer hybrid with a dentinal bonding agent and were cemented in a standardized manner to periodontally compromised molars. After 6 months the teeth were carefully extracted, stained, embedded, and sectioned, and the in vivo microleakage was measured. ANOVA disclosed significant differences between groups, and a multiple comparisons test revealed that the zinc phosphate group leaked significantly more than other cement groups.

Determination of amide-type local anaesthetics by direct injection of plasma in a column-switching high-performance liquid chromatographic system using a pre-column with a semipermeable surface

A high-performance liquid chromatographic method using column switching was applied to the direct determination of two local anaesthetics, ropivacaine and bupivacaine, in human plasma. The method is intended to be used in a combined LC-GC system; here only the LC-part is described. After addition of internal standard, the samples were filtered and directly injected into a semipermeable surface (SPS) pre-column where the analytes were strongly retained and separated from many endogenous compounds by a short washing step. The retained analytes were transferred by a buffered methanol phase from the pre-column into a carbonaceous HPLC column and they were detected by UV detection at 254 nm. The SPS pre-column could withstand numerous (> 200) direct injections of plasma samples (10 microliters). The method has a detection limit of 8.2 ng and requires a total assay time of 15 min per plasma sample. Quantitative recoveries were obtained over the range 3.3-114 micrograms/ml with inter-day precisions of 1.6-5.2% (C.V.).

Impairment of salivary epidermal growth factor secretory response to esophageal mechanical and chemical stimulation in patients with reflux esophagitis

OBJECTIVES

It has been demonstrated recently that salivary epidermal growth factor (sEGF) output in healthy individuals is strongly and significantly influenced by esophageal intraluminal mechanical and chemical stimuli. Therefore, we have studied the impact of intraesophageal mechanical and chemical stressors on the rate of secretion of sEGF in 14 patients with reflux esophagitis (RE), and compared these results with corresponding parameters measured in 14 sex- and age-matched controls.

METHODS

EGF was assessed in saliva collected during basal conditions, chewing of parafilm, placement of esophageal tubing, inflation of intraesophageal balloons, and perfusion with NaCl, HCl, and HCl/pepsin solutions. The concentration of sEGF was measured with an RIA kit from Amersham (Arlington Heights, IL).

RESULTS

The concentrations of sEGF were (mean +/- SEM) 2.50 +/- 0.32 ng/ml and 2.00 +/- 0.37 ng/ml in basal saliva and during stimulation by chewing the parafilm, respectively. Basal sEGF value appeared to be significantly higher than in controls (2.50 +/- 0.32 vs. 1.90 +/- 0.22 ng/ml, p < 0.05, in one-tailed t test). Placement of intraesophageal tubing resulted in a significant decline of sEGF concentration, compared with parafilm-stimulated conditions (1.25 +/- 0.12 vs. 2.00 +/- 0.37 ng/ml, p < 0.0001) and corresponding tubing-stimulated sEGF value in controls (1.25 +/- 0.12 vs. 1.52 +/- 0.16 ng/ml, p < 0.05). sEGF concentrations after inflation of intraesophageal balloons and subsequent perfusion with initial saline, HCl, HCl/pepsin, and ending saline were also highly significantly lower (1.05 +/- 0.18 ng/ml, p < 0.001; 1.10 +/- 0.20 ng/ml, p < 0.001; 1.10 +/- 0.18 ng/ml, p < 0.001; 1.10 +/- 0.19 ng/ml, p < 0.001; and 1.05 +/- 0.18 ng/ml, p < 0.001, respectively) than sEGF concentration recorded during stimulation with parafilm. Concentrations of sEGF during esophageal perfusion with HCl, HCl/pepsin, and ending saline were also significantly lower than corresponding values in controls (1.10 +/- 0.18 vs. 1.49 +/- 0.11 ng/ml, p < 0.05; 1.10 +/- 0.19 vs. 1.59 +/- 0.11 ng/ml, p < 0.05; and 1.05 +/- 0.18 vs. 1.65 +/- 0.13 ng/ml, p < 0.01, respectively). The rate of sEGF output, which was 1.30 +/- 0.24 ng/min during basal conditions, increased significantly during stimulation with parafilm (2.30 +/- 0.38 ng/min, p < 0.05). Both basal and parafilm-stimulated sEGF outputs were somewhat higher, although nonsignificantly, than corresponding values recorded in healthy individuals. Mechanical and chemical stimulation (initial NaCl, HCl, and ending NaCl) failed to evoke a significant increase in sEGF output over the value observed during parafilm stimulation in patients with RE, although such a significant increase was clearly demonstrated in healthy individuals. Therefore, sEGF output in patients with RE remained significantly lower than corresponding values recorded in controls during an entire mechanical stimulation (2.65 +/- 0.35 vs. 4.60 +/- 0.85 ng/min, p < 0.001, after placement of intraesophageal tubing and 2.80 +/- 0.54 vs. 5.15 +/- 0.70 ng/min, p < 0.001, after inflation of balloons). sEGF output in patients with RE remained also significantly lower than adequate control values during chemical stimulation (3.65 +/- 0.64 vs. 5.20 +/- 0.60 ng/min, p < 0.05, during perfusion with initial saline; 3.70 +/- 0.70 vs. 5.20 +/- 0.60 ng/min, p < 0.05, during perfusion with HCl; 3.70 +/- 0.52 vs. 5.55 +/- 0.72 ng/min, p < 0.01, during perfusion with HCl/pepsin, and 3.30 +/- 0.56 vs. 5.80 +/- 0.86 ng/min, p < 0.001, during ending saline).

CONCLUSION

Impairment in sEGF secretion during mechanical and chemical intraesophageal stimulation, mimicking the natural scenario occurring during gastroesophageal reflux, may facilitate the development of esophageal mucosal pathology and delay the healing of already developed mucosal injury.

[Serological investigation on intrafamilial transmission of HCV infection]

To clarify the intrafamilial transmission of HCV infection, the antibody to HCV was assayed in 124 serum samples from the family members of 60 HCV-Ab (+) index cases (group C), and compared with that from 83 family members of 40 HCV-Ab (-) index patients with hepatitis B (group B), Nine of 124, including 2 parents, 6 spouse and 1 granddaughter, were positive for anti-HCV. The prevalence of anti-HCV was 7.3% (9/124) in total, and 1.85% (2/108) in the subjects who had no history of blood donation. None of 83 was positive for anti-HCV in group B. On the other hand, the prevalence of HBV infection was 25.33% in the group of HCV infection only, and 40.91% in the group with HBV/HCV double-infection or HBV infection. It indicates that the risk of HBV intrafamilial transmission is higher than that of HCV, and the risk of transmission of HCV from mother to infant may be lower than that of sexual transmission.

[Atrial specific granules are an intracellular calcium store]

In order to elucidate whether the secretion of atrial natriuretic peptide (ANP) is correlated to the release of calcium (Ca) from the atrial specific granules (ASG), it is necessary to explore whether the ASG contain highly concentrated Ca and how the high Ca is maintained in the ASG. The present study was designed to determine Ca in the ASG with the quantitative electron microscope X-ray microanalysis and Ca(2+)-ATPase with electron microscopic (EM) cytochemical technique. The ultrathin cryosections of rapid frozen fresh rat auricles were used for measuring Ca concentration with a JEM-1200EX electron microscope equipped with a Link AN 10,000 energy dispersive X-ray spectroscope. The measurement showed that the Ca concentration in the ASG was quite high, being 81 +/- 15 mmol/kg (n = 10), comparable with that found in the sarcoplasmic reticulum. With the Ca(2+)-ATPase EM cytochemical technique, the reaction products proved to be deposited on the membrane of the ASG. It was postulated that the Ca(2+)-ATPase on the membrane of ASG pumped Ca2+ out of the cytosol into the ASG and thus maintained a high Ca concentration inside the ASG. Therefore, the ASG might be considered to be a Ca store in atrial cardiocytes.

Peptide-antibody conjugates for tumour therapy: a MHC-class-II-restricted tetanus toxin peptide coupled to an anti-Ig light chain antibody can induce cytotoxic lysis of a human B-cell lymphoma by specific CD4 T cells

Anti-idiotype antibody therapy of B-cell lymphomas, despite numerous promising experimental and clinical studies, has so far met with limited success. Tailor-made monoclonal anti-idiotype antibodies have been injected into a large series of lymphoma patients, with a few impressive complete tumour remissions but a large majority of negative responses. The results presented here suggest that, by coupling to antilymphoma idiotype antibodies a few molecules of the tetanus toxin universal epitope peptide P2 (830-843), one could markedly increase the efficiency of this therapy. We show that after 2-hr incubation with conjugates consisting of the tetanus toxin peptide P2 coupled by an S-S bridge to monoclonal antibodies directed to the lambda light chain of human immunoglobulin, human B-lymphoma cells can be specifically lysed by a CD4 T-lymphocyte clone specific for the P2 peptide. Antibody without peptide did not induce B-cell killing by the CD4 T-lymphocyte clone. The free cysteine-peptide was also able to induce lysis of the B-lymphoma target by the T-lymphocyte clone, but at a molar concentration 500 to 1000 times higher than that of the coupled peptide. Proliferation assays confirmed that the antibody-peptide conjugate was antigenically active at a much lower concentration than the free peptide. They also showed that antibody-peptide conjugates required an intact processing function of the B cell for peptide presentation, which could be selectively inhibited by leupeptin and chloroquine.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemically-modified tetracycline normalizes collagen metabolism in diabetic rats: a dose-response study

An earlier study indicated that a chemically-modified non-antimicrobial tetracycline (4-de-dimethylaminotetracycline; CMT-1) can inhibit excess collagenase activity in the connective tissues of diabetic rats, however, the optimum oral dose and resulting serum concentration were not determined. In the current study, adult male Sprague-Dawley rats (body weight approx. 350 g) were made diabetic by streptozotocin injection and administered by oral gavage either 0, 1, 2, 5, or 10 mg CMT-1 per day. After 3 weeks of drug therapy, the rats were killed and gingiva, skin, and serum collected. The tissues were 1) extracted, partially purified and analyzed for collagenase activity using [3H-methyl] collagen as substrate and SDS-PAGE/fluorography; 2) extracted in neutral salt and dilute acid solutions (4 degrees C) to assess collagen solubility; and 3) analyzed for hydroxyproline to determine tissue (skin) collagen mass. Serum was analyzed for glucose and CMT-1 concentration, the latter by HPLC. Inducing diabetes dramatically increased both gingival and skin collagenase activity and reduced skin collagen mass by 69.8%. Increasing the oral dose of CMT-1 progressively increased the serum concentration of the drug from 0.6-6.5 micrograms/ml and progressively decreased the excessive collagenase activity in gingiva and skin (p < 0.01 vs untreated diabetics). Although skin collagen mass tended to be increased at all oral doses of CMT-1, only the 5 mg dose effect was statistically significant (p < 0.01). The diabetes-induced reduction in collagen solubility, a classic abnormality (reflecting excessive collagen crosslinking) of this disease, was also normalized by CMT-1 therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Atomic-nitrogen production in a radio-frequency plasma source

The first high-resolution study, to our knowledge, of the optical emission from an Oxford Applied Research MPD21 nitrogen-plasma source is reported. The spectroscopic results clearly show that the MPD21 nitrogen-plasma source generates an appreciable flux of nitrogen atoms. This suggests that nitrogen atoms are the plasma species responsible for the successful p-type doping of ZnSe:N and related alloys.

Effect of esophageal intraluminal mechanical and chemical stressors on salivary epidermal growth factor in humans

Although various animal and clinical studies have demonstrated the significant effect of salivary epidermal growth factor (sEGF) on esophageal morphology and function, its secretory patterns still remain inadequately explored. Therefore, we have studied the impact of esophageal mechanical and chemical stimuli on sEGF in humans. sEGF was measured in saliva collected during basal conditions, chewing of parafilm, placement of esophageal tubing, inflation of intraesophageal balloons, and perfusion with NaCl, HCl, and HCl/pepsin solutions. The concentration of sEGF was measured with a radioimmunoassay kit from Amersham (Arlington Heights, IL). The concentration of sEGF in basal saliva was (mean +/- SEM) 2.08 +/- 0.22 ng/ml. Chewing the parafilm resulted in a significant decline of sEGF concentration to the value of 1.39 +/- 0.16 ng/ml (p < 0.0005). Similar decline in sEGF concentration also prevailed after placement of intraesophageal tubing (p < 0.03), and inflation of intraesophageal balloons (p < 0.01). This decline intensified significantly when prolonged esophageal perfusion with saline was implemented (p < 0.03 vs. tubing). Substitution of NaCl with HCl in the second and third perfusion periods prevented the decline in sEGF concentration, whereas HCl accompanied by pepsin enhanced sEGF concentration. The rate of sEGF output was 0.90 +/- 0.13 ng/min during basal conditions and increased significantly during parafilm chewing (1.53 +/- 0.25 ng/min; p < 0.05). However, sEGF secretion during both placement of esophageal tubing and inflation of balloons increased 4.1- and 4.9-fold, respectively (p < 0.002 and < 0.00005), over the basal value, and 2.4- and 2.9-fold, respectively, over the parafilm stimulated secretion. Subsequently, we observed a further significant decline of sEGF output (p < 0.05) which was sustained during perfusion of the esophagus with saline. Interestingly, esophageal perfusion with HCl prevented the decline of sEGF secretion observed during perfusion with saline. sEGF output during esophageal perfusion with HCl/pepsin exhibited a strong increase, reaching the value of 5.86 +/- 0.70 ng/ml. This value corresponds to a 58% increase over the secretory rate observed during mechanical stimulation by placement of esophageal tubing (3.71 +/- 0.47; p < 0.05). HCl/pepsin-induced potentiation of sEGF secretion was also highly significantly increased over both the value recorded during basal (p < 0.0005) and parafilm-stimulated (p < 0.002) conditions. Subsequent substitution of HCl/pepsin solution with a final saline perfusate still maintained enhanced sEGF output, compared with both basal (p < 0.02) and parafilm-stimulated conditions (p < 0.02).(ABSTRACT TRUNCATED AT 400 WORDS)

Circadian rhythm in aspirin (ASA)-induced injury to the stomach of the fasted rat

Circadian rhythms exist in several gastric parameters affecting ulcerogenesis. This study investigated possible circadian rhythmicity in observed aspirin (ASA)-induced gastric lesions in the rat. In five experiments 183 rats were studied at 14 time points over a 24-hr period. Rats were adapted for three weeks on a 12-hr light schedule, fasted 18 hr, then given oral acidified ASA. One hour later, the rats were sacrificed, the stomachs were removed, stretched flat, photographed, scanned, and measured for percent area of gross lesions in the gastric corpus by computer planimetry. Cosinor rhythmometric analysis showed a significant (P < 0.001) rhythm. Mean of rhythm (MESOR) was 5.60 +/- 0.25% of total corpus. Amplitude was 25.89 +/- 6.07% of MESOR. Peak time (acrophase) was 1909 +/- 0101 hr after lights on. Thus, gastric vulnerability to ASA injury exhibited circadian rhythmicity with peak injury during the dark period in this species.

Evidence on secretion of epidermal growth factor by the esophageal mucosa in humans

Luminal release of esophageal epidermal growth factor (EGF) into the perfusing solutions (saline, HCl, and HCl/pepsin), aspirated with the newly developed esophageal perfusion catheter, was measured in 20 healthy volunteers (12 male, 8 female; mean age 40 yr; range 30-56 yr). A potential salivary contamination was excluded by a complete seal (with two balloons) of perfused esophageal segment and by a simultaneous, carefully monitored, collection of saliva. The concentration of EGF in each of 16 fully recovered 2-min perfusion samples was measured by RIA kit (Amersham, IL). The concentration of EGF in recovered NaCl perfusate varied between (mean +/- SEM) 1.78 +/- 0.19 and 2.14 +/- 0.14 ng/ml, whereas output varied between 9.25 +/- 0.98 and 11.14 +/- 0.82 ng/min. During perfusion with HCl, both the concentration of EGF within the esophageal perfusate and its secretion declined significantly to a value of 0.68 +/- 0.17 ng/ml (p < 0.0001) and 3.56 +/- 0.90 ng/min (p < 0.0001), respectively. Introduction of pepsin into an acidic perfusion solution (0.5 mg/ml of HCl) resulted in a significant increase in EGF concentration (1.99 +/- 0.36 ng/ml; p < 0.001) and output (10.24 +/- 1.84; p < 0.01), compared with EGF values recorded during perfusion with HCl. EGF output, calculated from a sealed 7.5-cm segment of the esophagus, was 10.39 +/- 0.89 ng/min, and was maintained at a steady state throughout an entire saline perfusion procedure. We present evidence that human esophageal mucosa has an enormous EGF secretory potential. The rapid esophageal EGF secretory response to intraluminal challenge with aggressive factors implies its role in the maintenance of the mucosal integrity.

Physical properties of fixed prosthodontic, resin composite luting agents

This study determined and compared physical properties of six fixed prosthodontic resin composite luting agents and one control. Inorganic filler content, compressive strength, diametral tensile strength, film thickness, and Knoop hardness were determined. The amounts of filler and the physical properties varied widely among materials. One material, which contained a minimal amount of filler, underwent so much plastic deformation that its strengths could not be measured. All other materials demonstrated high strengths. The materials with the least filler demonstrated the least resistance to indentation. The material with the lowest film thickness had not set at the time of measurement, 10 minutes after mixing. Most materials had unacceptable film thicknesses. Only one material demonstrated acceptable physical properties throughout the study.

Elevated endometrial natural killer cell activity during early porcine pregnancy is conceptus-mediated

This study investigated an extended time course of endometrial NK cell activity during gestation and the mechanisms underlying changes in uterine NK cell activity in pigs. Endometrial tissues were collected from cyclic, pseudopregnant and pregnant nulliparous pigs on various days post-estrus, and from pigs 10 days after insemination with seminal plasma or killed spermatozoa. NK effector cells were isolated from each endometrial sample, size fractionated and tested for cytolytic activity against NK target cells (K562) using chromium release assays and immunocytochemically for the frequency of perforin-positive cells. Various cell fractions showed different levels of NK activity and had different proportions of cells expressing perforin. Morphologically, cells in the fraction with maximal NK activity almost all showed typical lymphocyte size and shape. Substantially elevated NK cell activity was recorded in pregnant pigs on days 10 and 20 of gestation. By day 30, the cytolytic activity declined dramatically to an almost undetectable level. Very little activity was found in uterine cells isolated from cyclic, pseudopregnant, and seminal plasma or killed spermatozoa inseminated animals, and no differences were detected either between follicular and luteal phases of the estrous cycle or between different days of pseudopregnancy. These results indicate that elevated NK cell activity during early porcine pregnancy cannot be attributed to contributions from either the maternal systemic endocrine status or from components of boar semen. The changes in NK cell activity observed in porcine endometrial tissues during early pregnancy must therefore be associated with the actual presence of conceptuses.

Compressive and diametral tensile strengths of current adhesive luting agents

Strength parameters greatly influence the selection of luting agents. This study compared the compressive and diametral tensile strengths of six classes of new adhesive luting agents (ALAs) with zinc phosphate as the controls. The 11 materials tested were prepared according to the manufacturers' instructions for use as luting agents. Mean compressive and diametral strengths and standard errors were calculated for each luting agent (n = 10). Analysis of variance was computed (p < 0.0011) and multiple comparisons tests were performed. Compressive strengths varied from 41.5 MPa for a hydroxyapatite ALA to 178.5 MPa for a composite resin ALA. Diametral tensile strengths ranged from 8.1 MPa for a hydroxyapatite ALA to 45.1 MPa for a composite resin ALA. Conventional powder-liquid glass ionomer ALAs, an encapsulated glass ionomer ALA, a composite resin-glass ionomer hybrid ALA, and the composite resin ALAs demonstrated significantly greater compressive and diametral strengths than the zinc phosphate cements.

The nitrogenase proteins of Rhizobium meliloti: purification and properties of the MoFe and Fe components

The alfalfa-Rhizobium meliloti symbiosis contributes a major portion of biologically fixed nitrogen to temperate zone forage crop production. Highly-purified molybdenum-iron (MoFe) and iron (Fe) nitrogenase components were obtained for the first time from extracts of R. meliloti bacteroids. Intact bacteroid cells were isolated anaerobically from 100 g quantities of alfalfa nodules following storage in liquid nitrogen. Centrifuged bacteroid extracts showed a marked reduction in specific activity when assayed at protein concentrations less than 1 mg/ml. Both nitrogenase proteins were resolved and purified to homogeneity as determined spectroscopically and by SDS-PAGE. The purified MoFe protein differed in several respects from previously characterized nitrogenase proteins. Saturation of the acetylene-reducing and proton-reducing activities of the R. meliloti MoFe protein required higher relative concentrations of Fe protein than nitrogenase proteins purified from free living diazotrophs. Electron allocation to dinitrogen reduction was sustained at component ratios similar to those present in bacteroid extracts, suggesting that while the observed saturation effects were not detrimental to physiological function in the symbiotic system, overall activity could be enhanced by higher levels of iron protein. Analyses of the MoFe protein gave 22 Fe, 22 labile sulfide and 1.7 Mo atoms per molecular unit of 215 kDa. Dithionite-reduced MoFe protein contained a spin 3/2 iron centre but had a lower visible absorbance at 360 nm than the equivalent Azotobacter chroococcum component. Amino-acid composition indicated a notably lesser tryptophan content, and cysteine content greater than that of the equivalent tetrameric protein of free living diazotrophs. Ratios of acidic and basic residues were similar to other MoFe proteins. Calculation of hydrophobicity and discriminant parameters gave values midway between those expected for soluble cytoplasmic proteins and peripheral membrane associated proteins. ADP was tightly bound by the dithionite-free MoFe protein containing reduced iron-molybdenum cofactor. The R. meliloti iron protein was found to be a 64 kDa homodimer containing a single 4Fe-4S metal centre.

Blood pressure and heart rate response to vasoactive agents in conscious diabetic rats

Blood pressure and heart rate responses to different vasoactive agents were observed in conscious streptozotocin-diabetic rats. An indwelling femoral artery catheter was used for direct measurement of arterial pressure and heart rate. The femoral vein was cannulated for drug administration. In a resting state diabetic rats showed lower heart rates and lower systolic blood pressure. The vasodepressor response to both acetylcholine and sodium nitroprusside was decreased, while the heart rate increase induced by the baroreceptor reflex was not altered. Both the increase in blood pressure and the reflex bradycardia to norepinephrine were decreased in the diabetic group. When the change in heart rate was plotted against blood pressure in response to norepinephrine, there was no difference in the two groups of animals. The vasodepressor response to isoproterenol, hydralazine, and verapamil in diabetic rats was unchanged. The results demonstrate a decreased vascular responsiveness in diabetic rats to norepinephrine, acetylcholine, and nitroprusside. The diabetes-induced vascular system changes require further study to understand the mechanisms involved.

Tetracycline administration increases protein (presumably procollagen) synthesis and secretion in periodontal ligament fibroblasts of streptozotocin-induced diabetic rats

Streptozotocin-induced, insulin-deficient diabetic adult rats were daily administrated either minocycline or a chemically-modified non-antimicrobial tetracycline (CMT) by oral gavage for a 3-week time period; untreated diabetic and non-diabetic rats served as controls. On day 21, all rats received an intravenous injection of 3H-proline followed by perfusion fixation with an aldehyde mixture at 20 minutes and 4 hours after isotope injection. The upper and lower mandibles of these rats were dissected and processed for quantitative electron microscopic autoradiography to study 3H-proline utilization by fibroblasts in the periodontal ligament (PDL) of molars. In the non-diabetic controls, at 20 min after 3H-proline injection, radioprecursor was incorporated by the Golgi-RER system of PDL fibroblasts. At the 4-h time period, most of the label was present over the collagen fibers around these cells. In contrast, PDL fibroblasts in the untreated diabetic rats showed marked abnormalities ultrastructurally and minimal uptake (20 min) and secretion (4 h) of labeled proline. At both time periods, in both minocycline- and CMT-treated diabetic rats, fibroblasts were structurally more normal and the radioprecursor was localized in the fibroblasts and the PDL matrix in a pattern similar to that seen in the control rats. These results suggest that the diabetes-induced structural abnormalities and suppression of synthesis and secretion of protein (presumably collagen and its precursor) by PDL fibroblasts can be restored to near-normal by administration of a tetracycline and that this effect is mediated by a non-antimicrobial property of this family of antibiotics.

Effect of seating force on film thickness of new adhesive luting agents

This study examined the effect of seating force on the film thickness of new adhesive luting agents. The method was in compliance with American National Standards/American Dental Association Specification No. 8 for zinc phosphate cement. The materials tested were zinc phosphate cement, glass ionomer cement, polycarboxylate cement, and a resinous cement with a dentinal bonding agent. All materials were manipulated exactly as described in the manufacturer's instructions, and an electronic gauge with an accuracy of 0.5 micron was used. Each class of material was measured 10 times at six different seating forces. Analysis of variance and multiple comparisons testing disclosed that the seating force and class of material strongly influenced the film thicknesses of luting agents. A mathematical model describing the response of zinc phosphate cement within the range tested was reported.

The effect of adhesive luting agent-dentinal surface interactions on film thickness

This study investigated the effect of luting agent-dentinal surface interactions on the film thicknesses of new adhesive luting agents. The method was in compliance with American National Standards Institution/American Dental Association (ADA) Specification No. 8 for zinc phosphate cement. In the control groups the luting agents were placed between two glass plates, as described in ADA Specification No. 8, but in the test groups the luting agents were positioned between a glass and a dentinal plate. The materials selected were zinc phosphate cement, glass ionomer cement, polycarboxylate cement, and a resinous cement with a dentinal bonding agent. A two-way analysis of variance was performed, and t tests were computed to compare glass with the dentinal plate within each material. Zinc phosphate and glass ionomer cements exhibited a significant decrease in film thickness when measured in contact with dentin, as compared with contact with the glass plate. However, polycarboxylate cement and the resinous cement with its dentin bonding agent showed a slight nonsignificant increase when contacting dentin, as compared with the glass plate. An explanation was offered and suggestions were made regarding future research.