Eosinophil chemotaxis inhibited by 5-lipoxygenase blockade and leukotriene receptor antagonism

We studied the effects of the 5-lipoxygenase inhibition and sulfidopeptidyl leukotriene receptor antagonism on lumenal chemotaxis of eosinophils in 124 guinea pig tracheal explant preparations from 62 animals. Cell migration was assessed histologically and by differential cell count, and airway narrowing was measured by calibrated micrometry. Intralumenal instillation of the chemotaxin, formyl-met-leu-phe (FMLP) caused migration of 163,509 +/- 18,103 eosinophils/cm segment (eos/cm) versus 15,443 +/- 3,557 eos/cm for segments receiving vehicle only (p < 0.001). Coincubation of FMLP with zileuton, a selective inhibitor of 5-lipoxygenase, caused a concentration-related inhibition of eosinophil migration. At 10(-10) M zileuton, cell migration caused by FMLP was decreased by 57% and nearly complete reduction to 17,200 +/- 3,620 eos/cm resulted after 10(-6) M zileuton (p < 0.001 versus FMLP). Lumenal narrowing caused by FMLP (15.3 +/- 3.4%) was attenuated maximally to 1.15 +/- 2.51% after 10(-8) M zileuton (p < 0.02). In 36 preparations, concentration of leukotriene B4 (LTB4) was measured in treated tracheal perfusate. LTB4 secretion caused by FMLP was 6.4 +/- 0.48 pg/ml versus 3.32 +/- 0.89 pg/ml for buffer control at 5 min (p < 0.02) and was undetectable 120 min after activation with FMLP. Blockade of LTB4-receptor with the selective antagonist, LTB4 dimethyl amide, caused > 90% inhibition of eosinophil migration (p < 0.001). Comparable results were obtained with zafirlukast, an LTD4-receptor antagonist. Our data demonstrate that both LTB4 and LTD4 facilitate eosinophil migration from lamina propria to lumen caused by the chemotaxin, FMLP, and that LTB4-induced eosinophil migration is accompanied by initial lumenal secretion of LTB4.

Influence of the intensity of NaCl solutions on adaptation degree and recovery time course

The degree of adaptation and the time course of recovery after adaptation to NaCl solutions of various intensities were examined by magnitude estimation and simple sensory reaction time using a test stimulus of constant intensity. The results show that the degree of adaptation increased with the adapting concentration following a negatively accelerated function. Similarly, all recovery curves were negatively accelerated functions of the recovery time. The relation between the recovery constant (time necessary to attain two-thirds of normal responsivity) and adapting concentration approximates with both criteria more or less a linear function. Thus the recovery constant is a positively accelerated function of the degree of adaptation. The relationship between concentration and degree of adaptation can be approximated by Beidler's equation of taste stimulation, while the time course of recovery can be expressed by an exponential equation that can also be related to Beidler's theory. The two criteria used showed similar deteriorating effects of taste adaptation, indicating that reaction time can also be a useful criterion of the level of sensory responsivity.

Quantitation of the cytosolic phospholipase A2 (type IV) in isolated human peripheral blood eosinophils by sandwich-ELISA

Sandwich enzyme-linked immunosorbent assay (sELISA) was developed for precise quantitation of cytosolic phospholipase A2 (cPLA2 type IV) concentration in isolated human peripheral blood eosinophils as an alternative to semiquantitative chemiluminescent assay employing immunoprecipitation/Western blot analysis. In this assay, monoclonal mouse anti-human cPLA2 antiserum was used as the capture antibody, polyclonal rabbit anti-human cPLA2 antiserum as the secondary antibody, and alkaline phosphatase-conjugated goat anti-rabbit IgG as the tertiary, reporter antibody. Purified human cPLA2 (0-1000 ng/ml) dissolved in Tris-HCl buffered saline was used as the standard protein. The detection limit for cPLA2 in 10(6) eosinophils was 0.109 ng/ml, and coefficients of inter- and intra-assay variation were 4.23% and 7.07%, respectively. There was no cross-reactivity with other (secretory) isoforms of PLA2 (sPLA2 types I-III) either from porcine pancreas, human synovial fluid, or bee venom. In separate studies, the recovery of cPLA2 was > 83% when eosinophil lysate was supplemented exogenously with two different concentrations of cPLA2. From a total protein content of 22.3 +/- 1.7 micrograms/10(6) cells, the baseline concentration of cPLA2 was 0.38 +/- 0.18 ng/10(6) cells in eosinophils obtained from mildly atopic donors. Immunoblotting studies confirmed the complete specificity for the type IV isoform as detected by sELISA. This sELISA method permits the precise quantitative assessment of cPLA2 in nanogram quantities per million cells, which has not previously been possible by immunoblotting analysis.

A new possible parameter for the detection of aneuploidy inducing substances: the analysis of qualitative and quantitative abnormalities of the spindle apparatus

In the present study, compared to other cytogenetic methods, we measured the number of aneuploid cells directly by analyzing anomalies of the mitotic spindle. Qualitative and quantitative abnormalities of the mitotic spindle apparatus in transformed and non-transformed cell lines in vitro were classified. We treated the different cell lines with well known aneugenic agents as Benomyl and Griseofulvin and investigated the mitotic spindle under different experimental conditions. The spindle apparatus was stained by indirect immunofluorescence and the chromatin was counterstained by fluorescent dyes. The mitotic spindle showed a great sensitivity to the aneuploidy-inducing substances used in our experiments. The spindle-disturbing effect of the tested substances was demonstrated to be dose- dependent. The morphological alterations appeared to be independent of the aneuploidy-inducing test substance used, but showed a relation to the dose and length of treatment. Thus, the analysis of the mitotic spindle may be a useful screening parameter for the detection of aneuploidy-inducing substances and further investigations will provide additional results to specific parameters.

The unique challenge of small intestinal transplantation

The past decade has seen major organ transplantation become routine. Although the small intestine can now be successfully transplanted alone or with other organs, the operation presents unique challenges which are reflected in lower survival rates compared with transplantation of other organs. This review presents the development of clinical small intestinal transplantation and its current status.

[Risk of hyperthyroidism in examinations with contrast media]

Investigations with contrast media inevitably lead to the patient being exposed to large amounts of iodine. Under certain preconditions this gentails danger for the patient by causing either iodine-induced hyperthyroidism, which is difficult to treat, or even a thyrotoxic crisis. Patients with normal thyroid function and size have only minute changes of thyroid hormones and TSH within the normal range and are not at risk. Patients with unknown hyperthyroidism--independent of the etiological form--and patients with functional autonomy are at risk of exacerbation of pre-existing hyperthyroidism or development of iodine-induced hyperthyroidism. This development depends on two factors: a) the volume of autonomous tissue and b) the quantity of iodine exposure. Besides contrast media, other sources of iodine excess are possible, such as iodine-containing disinfectants, secretolytic agents, antiarrhythmics like amiodarone, eye drops and ointments, geriatrics, skin ointments, toothpaste etc. The development of hyperthyroidism can be prevented by combined treatment with antithyroid drugs and perchlorate in the case of preexisting hyperthyroidism or the urgent clinical suspicion of thyrotoxicosis or with perchlorate alone, when the patients is euthyroid and does not have a large nodular goitre.

Dehydroepiandrosterone-induced lipid peroxidation in rat liver mitochondria

Administration of dehydroepiandrosterone (DHEA), a steroid hormone of the adrenal cortex which acts as a peroxisome proliferator and hepatocarcinogen in the rat, caused an increase in NADPH-dependent lipid peroxidation in mitochondria isolated from the liver, kidney and heart, but not from the brain. The effect of DHEA on rat liver mitochondrial lipid peroxidation became discernible after feeding steroid-containing diet (0.6% w/w) for 3 days, and reached maximal levels between 1 and 2 weeks. DHEA in the concentration range 0.001-0.02% did not significantly increase lipid peroxidation compared to the control. Lipid peroxidation was significantly enhanced in animals given a diet containing > or = 0.05% DHEA. The addition of DHEA in the concentration range 0.1-100 microM to mitochondria isolated from control rats had no effect on lipid peroxidation. It seems, therefore, that the steroid effect is mediated by an intracellular process. Our data indicate that induction of mitochondrial membrane lipid peroxidation is an early effect of DHEA administration at pharmacological doses.

Biotransformation of the aerosol propellant 1,1,1,2,3,3,3-heptafluoropropane (HFA-227): lack of protein binding of the metabolite hexafluoroacetone

The biotransformation of the aerosol propellant 1,1,1,2,3,3,3-heptafluoropropane (HFA-227) was investigated in rats in vivo and in rat and human liver microsomes. In the urine of rats exposed to 5000 ppm HFA-227 for 6 hr, very small amounts of hexafluoroacetone trihydrate were identified as an HFA-227 metabolite by 19F-NMR. Fluoride concentrations in the urine samples (0-48 hr after the end of the exposure) from exposed animals were not significantly different from those found in samples from nonexposed rats. In rat and human liver microsomes, fluoride and hexafluoroacetone trihydrate formation from HFA-227 was detected in very low levels only in liver microsomes from pyridine-treated rats and in two of eight human liver microsome samples, which exhibited the highest cytochrome P4502E1 activities. Because some aldehydes may covalently bind to proteins and the formation of fluorinated protein adducts has been implicated in immune-mediated hepatitis induced by halothane, the binding of hexafluoroacetone trihydrate to proteins was also investigated. Hexafluoroacetone trihydrate also gave only a very small resonance in fluorine NMR experiments when binding to human serum albumin was studied in comparison with the acylating agent S-ethyltrifluoroacetate. Moreover, no fluorine-containing products were formed by the reaction of hexafluoroacetone trihydrate with N alpha-acetyl-L-lysine, and hexafluoroacetone trihydrate was not metabolized to fluorine-containing metabolites or inorganic fluoride in rats. Comparative studies in human liver microsomes demonstrated that a halothane metabolite may covalently bind to proteins; in contrast, metabolism and covalent binding of HFA-227 could not be demonstrated. In summary, these data indicate that HFA-227 is biotransformed at very low rates to hexafluoroacetone trihydrate but irreversible binding of hexafluoroacetone trihydrate cannot be demonstrated, even with the application of very sensitive methods, and is considered unlikely, based on the combination of the results obtained.

Isolation of Mycoplasma conjunctivae from conjunctival swabs of Alpine ibex (Capra ibex ibex) affected with infectious keratoconjunctivitis

Mycoplasma conjunctivae was isolated four times from the eyes of nine Alpine ibex (Capra ibex ibex) suffering from keratoconjunctivitis. The animals examined were affected in two different outbreaks in the Swiss Alps. Parasitological and bacteriological studies, including investigations for chlamydia and mycoplasmas, were performed. The results indicate that M. conjunctivae is the primary pathogenic agent causing infectious keratoconjunctivitis in this species.

Increase of lipid peroxidation in rat liver microsomes by dehydroepiandrosterone feeding

Oral administration of the adrenal steroid dehydroepiandrosterone (DHEA), a peroxisome proliferator and hepatocarcinogen in the rat, caused an increase in NADPH-dependent lipid peroxidation in microsomes isolated from rat liver and kidney cortex, but not from brain. The increase of liver microsomal lipid peroxidation was greater in male than in female rats. the effect of DHEA on lipid peroxidation became discernible after feeding steroid-containing diet (0.6%) to male and female rats for 2 and 3 days and reached maximal levels at 1 and 2 weeks, respectively. The increase of microsomal lipid peroxidation reached a plateau stimulation at 0.05% in the diet. The addition of DHEA in the concentration range 0.1-100 microM to microsomes isolated from control rats had no effect on lipid peroxidation. Furthermore, a significant increase of the endogenous concentration of thiobarbituric acid reactive substances was found in microsomes after DHEA-administration at 0.05% in the diet. These results provide in vivo evidence that DHEA can cause lipid peroxidation in rat liver. Administration of DHEA at 0.6% in the diet for 7 consecutive days also significantly enhanced NADH- and ascorbate-dependent lipid peroxidation in liver microsomes. The DHEA-stimulated rat liver microsomal lipid peroxidation was completely inhibited by EDTA but not by superoxide dismutase, catalase or mannitol applied as OH-radical scavenger. The findings indicate that membrane lipid peroxidation is an early effect of DHEA, and that this process may be involved in the steroid-induced carcinogenesis in rats.

Eosinophil VLA-4 binding to fibronectin augments bronchial narrowing through 5-lipoxygenase activation

We examined the effect of ligation of human eosinophils activated by platelet-activating factor (PAF) to soluble human fibronectin (FN) on the augmented contractile response of human bronchial explants. Styrene microplate wells were FN-coated and eosinophils were allowed to adhere in the presence of 1) buffer control, 2) 20 micrograms/ml monoclonal antibody (HP2/1) to the alpha 4 beta 1 ligand (VLA-4) on the eosinophils, 3) 20 micrograms/ml anti-CD18 R15.7, 4) 20 micrograms/ml anti-CD16 3G8, or 5) 10(-6) M A63162, a 5-lipoxygenase inhibitor. Sixty minutes later, treated cells were activated with either buffer or 10(-6) M PAF. Airway luminal diameter was assessed by computerized videomicrometry as a function of pixel number, and activation of eosinophils was confirmed by measurement of leukotriene C4 (LTC4) secretion. Ligation with FN caused an increase in PAF-stimulated LTC4 secretion from 276 +/- 75.6 pg/10(6) cell at baseline to 606 +/- 90.2 pg/10(6) cell (P < 0.01). This corresponded to augmented luminal narrowing of human bronchial explants from 25.3 +/- 9.39% (PAF activation alone) to 42.9 +/- 8.0% (PAF-activated eosinophils + FN) (P < 0.01). Both augmented airway luminal narrowing and increased LTC4 secretion caused by PAF-activated cells after FN ligation were blocked completely by anti-VLA-4 MAb (P < 0.05 vs. control). Pretreatment with 10(-6) MA63162 inhibited completely the PAF-stimulated LTC4 secretion to baseline level ( P < 0.001). Inhibition of 5-lipoxygenase similarly blocked luminal narrowing caused by eosinophils stimulated by PAF by > 95% (P < 0.001). We demonstrate that the binding of human eosinophils to the matrix protein FN causes augmented secretion of LTC4 which, in turn, causes augmented luminal narrowing of explanted human bronchi in vitro. We also demonstrate that the augmented activity is blocked selectively by pretreatment with specific monoclonal antibody against VLA-4 and blockade of eosinophil 5-lipoxygenase inhibits both LTC4 secretion and airway narrowing after PAF-stimulation.

Combined liver-spleen-small intestine grafting in a rat model: role of transplanting additional lymphoid tissue on survival

The aim of this study was to develop suitable models of combined intestinal grafting to examine the enhancing effect of intestinal grafting with additional lymphoid tissue using 30% of the liver mass and the whole spleen on recipient survival in the absence of immunosuppression. Grafts from DA (RT1a) rats were transplanted orthotopically to PVG (RT1(1)) recipients according to the following design: group 1 (n = 6), en bloc 30% liver/entire SB/spleen; group 2 (n = 7), en bloc 30% liver/SB; group 3 (n = 7), SB/spleen and group 4 (n = 7), SB control for the preceding groups. The orthotopic nature and proximal interposition of the SB graft allowed the assessment of protection afforded by components of the cluster on the SB graft using survival endpoints. Although group 4 hosts survived half as long compared to other groups, statistical significance was reached only in the case of group 1; group 1 MST equalled 15.3 days, significantly higher than group 4 (p = 0.01). Acute rejection was present in every grafted tissue and was equivalent whether liver was included or excluded in the cluster. GVHD was absent postoperatively using clinical or histological criteria; recipient spleens showed hyperplasia, donor spleens depicted lymphocytic depletion on histology. This study determined that statistically proven enhanced survival was obtained only after grafting 30% liver plus spleen with the entire SB. GVHD was rare in the fully allogeneic system despite transplanting a massive load of lymphoid tissue. The surgical models used in this study employing liver in the cluster, address the important question of how best to evaluate the role of heterotopic accessory liver grafting in providing tolerance to co-transplanted small intestine.

[Helicobacter pylori eradication therapy with bismuth citrate/amoxycillin combination therapy]

The efficacy of a new combination preparation containing bismuth citrate and amoxicillin in one tablet was compared with the efficacy of bismuth citrate monotherapy in a randomised double-blind study on the eradication of Helicobacter pylori. The study involved 70 H. pylori positive (antrum biopsies showing a positive urease test) patients with non-ulcer dyspepsia and chronic gastritis. The treatment period was 14 days; 35 patients in group 1 received 2 tablets tid containing the bismuth citrate amoxicillin combination (BIAM tablet; 250 mg amoxicillin base and 120 mg bismuth); 35 patients in group 2 were treated with 2 tablets tid containing bismuth citrate (BI tablet; 120 mg bismuth). Total daily dose was therefore 1500 mg amoxicillin + 720 mg bismuth in group 1 patients resp. 720 mg bismuth in group 2 patients. 4 weeks after therapy H. pylori could not be histologically detected in the antrum of 22 patients (63%) in group 1 and 8 patients (24%) in group 2. Thus in group 1 (BIAM) a significantly higher eradication rate (p < 0.001) was shown than in group 2 (BI). Inflammation characterized by the infiltration of polymorphonuclear cells was significantly (p < 0.01) less pronounced in group 1 (BIAM) than in group 2 (BI) 4 weeks after the end of treatment. Gastrointestinal distress was quantified by evaluation of 13 different symptoms using a fourpoints scale at the beginning of the study and after 2 and 6 weeks. The sum of scores decreased by 81% in group 1 (BIAM) and 71% in group 2 (BI) after 6 weeks.

Central venous puncture versus cutdown for permanent pacemaker lead insertion: a modified double introducer technique

OBJECTIVE

The comparative safety of central venous puncture versus cutdown technique for access to the right heart.

EXPERIMENTAL DESIGN

A retrospective review of five hundred and fifty-five single and dual chamber permanent pacemaker implants performed between January of 1987 and December of 1993.

SETTING

Review was performed at St. Vincent's Hospital in New York, New York and its teaching affiliate, Huntington Hospital, Huntington, New York.

RESULTS

A total of 310 venous punctures were performed. The complication rate was 3.5% overall, with one procedure related death (0.3%) from major venous laceration; a stiff 14 French dilator sheath was employed in this case. There were no comparable complications in the 245 lead placements performed by various cutdown methods.

CONCLUSION

Venous cutdown is a safe and effective method for placement of single and dual chamber pacemaker leads. If unsuccessful, the cephalic vein guidewire and double introducer techniques may be employed to rule out placement of dual chamber leads through a hypoplastic cephalic vein, using introducers not larger than 10 French. In properly selected patients, this technique could potentially prevent the complications associated with venous puncture.

The immunomodulatory effect of leflunomide in rat cardiac allotransplantation

Leflunomide, a novel immunosuppressant, has been the subject of recent preclinical studies using solid organ allo- and xenotransplantation models. The objectives of this study were to evaluate the efficacy and toxicity of leflunomide using a rat cardiac allotransplant model in two different strain combinations (DA x PVG and DA x Lew). Leflunomide, at doses ranging between 5 and 30 mg/kg, prolonged graft survival in both strain combinations as effectively as CsA and FK506 1 mg/kg (P < 0.05). A dose-dependent effect was seen only after a longer treatment course. When ongoing rejection was intercepted early (postoperative day 2), 5 mg/kg was as effective as 1 mg/kg FK506 (P > 0.05) but was inferior to CsA in the DA x PVG combination (P < 0.05). However, in the DA x Lew combination, leflunomide was equally as efficacious as 15 mg/kg CsA and 1 mg/kg FK506 (P > 0.05). If ongoing rejection was treated at postoperative day 4, 10 mg/kg leflunomide was not only as effective as 15 mg/kg CsA and 1 mg/kg FK506, but demonstrated a dose-dependent increase in graft survival in both strain combinations. The toxicity of leflunomide at doses of especially 5-20 mg/kg was minimal in comparison to therapeutic doses of CsA and FK506 using body weight and biochemical parameters of renal and liver function. These in vivo observations convincingly show leflunomide to be equally as potent an immunosuppressant as CsA and FK506 in transplant rejection. It is also well tolerated on long-term administration and, by virtue of this fact, is a potentially suitable candidate for clinical transplantation.

Transport of dehydroepiandrosterone and dehydroepiandrosterone sulphate into rat hepatocytes

The purpose of the present study was to characterize the transport of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulphate (DHEAS) into hepatocytes at physiological and pharmacological concentrations. Hepatocytes were isolated from female Sprague-Dawley rats by collagenase perfusion. Uptake of [3H]DHEA and [3H]DHEAS at increasing concentrations (3.5 nM-100 microM) was measured by the rapid filtration technique at 30 s intervals up to 120 s. The uptake of DHEAS by hepatocytes was saturable (Km = 17.0 microM; Vmax = 3.7 nmol/min/mg cell protein). In contrast, a specific saturable transport system for DHEA could not be detected in rat hepatocytes. It is suggested that DHEA enters the cell by diffusion. The uptake of DHEAS could be inhibited by antimycin A, carbonylcyanide-m-chlorophenylhydrazone, and dinitrophenol (inhibitors of the mitochondrial respiratory chain), by dinitrofluorobenzene and p-hydroxymercuribenzoate (NH2- and SH-blockers, respectively), and by monensin (Na(+)-specific ionophore). No inhibition was seen in the presence of ouabain (inhibitor of Na(+)-K(+)-ATPase) and phalloidin (inhibitor of cholate transport and actin-blocker). Interestingly, DHEAS uptake was inhibited by bile acids (cholate, taurocholate and glycocholate). Conversely, [3H]cholate uptake was strongly inhibited by DHEAS, which indicates a competition for the same carrier. Replacement of sodium ion with choline markedly decreased uptake velocity at pharmacological DHEAS concentrations. The results suggest that DHEAS uptake is a saturable, energy-dependent, carrier-mediated, partially Na(+)-dependent process, and that DHEAS may be taken up via the multispecific bile acid transport system.

Sequential appearance and ultrastructure of amphophilic cell foci, adenomas, and carcinomas in the liver of male and female rats treated with dehydroepiandrosterone

Dehydroepiandrosterone (DHEA), a hormone of the adrenal cortex, acts as a peroxisome proliferator and hepatocarcinogen in rats upon long-term treatment with high doses in the diet. The aim of the present study was to identify the site of origin of hepatocellular neoplasms and the sequence of preneoplastic lesions. Twenty-five female and 25 male rats were given 0.6% DHEA in the diet; 25 animals of each sex were controls. Groups of 5 treated and untreated animals were sacrificed after 4, 20, 32, 70, and 84 wk. Amphophilic cell foci were detected after 32 wk of treatment; they developed from the liver parenchyma almost exclusively in the vicinity of portal tracts. Adenomas of the amphophilic or amphophilic/tigroid cell phenotype were observed at 70 wk of treatment. Highly differentiated hepatocellular carcinomas presenting a similar cellular phenotype occurred after 70-84 wk. The incidence of hepatocellular carcinomas was 44% in female and 11% in male rats. Ultrastructural studies of the amphophilic cell foci and tumors revealed a marked proliferation of mitochondria and a moderate proliferation of peroxisomes in all lesions. In addition, a very strong peroxisome proliferation was observed in perivenular hepatocytes in the liver of female rats. Peroxisomes usually lacked core and showed flocculent matrices. In male rats, weak peroxisomal proliferation was observed. Typical morphological abnormalities of these peroxisomes were paracrystalline inclusions of striated appearance. Although the most prominent peroxisome proliferation was observed in perivenular hepatocytes, these cells did not seem to be involved in tumor development. In contrast, the morphological similarity of the amphophilic cell foci and the amphophilic/tigroid cell adenomas and carcinomas, their coincident localization near portal tracts, and the sequential appearance of these lesions suggest that the amphophilic cell foci represent an early stage in DHEA-induced hepatocellular neoplasia. Mitochondrial proliferation as the most prominent feature in all stages of this model of hepatocarcinogenesis may offer a new approach for analysis of hepatocarcinogenesis induced by DHEA and possibly other peroxisomal proliferators.

Identification of the transcriptional activator controlling the butanediol fermentation pathway in Klebsiella terrigena

The gene budR, whose product is responsible for induction of the butanediol formation pathway under fermentative growth conditions in Klebsiella terrigena, has been cloned and sequenced. This gene is separated from the budABC operon by a nontranslated region of 106 bp and transcribed in the opposite direction. budR codes for a protein of molecular weight 32,124, the sequence of which exhibits characteristics of regulators belonging to the LysR family. When transferred into the heterologous host Escherichia coli, budR activates expression of budA'-lacZ transcriptional and translational fusions with a regulatory pattern identical to that in K. terrigena, namely, induction by acetate, low pH, and anaerobiosis. Induction by acetate was specific, indicating that it is the physiological inducer. Primer extension analysis located the start site of transcription to two positions, 23 and 24 bp upstream of the budR initiation codon, and also showed that BudR strongly autoregulates its own expression. The products of fhlA, arcA, hip, ntrA, and katF did not influence expression of the bud operon. A mutation in fnr, however, led to a threefold increase in expression, indicating that Fnr acts as a repressor. The results support the notion that BudR coordinates the activity of the energy-conserving, nonreductive, but acidifying acetate formation pathway with the expression of the non-energy-conserving, reductive, but nonacidifying butanediol pathway.

Biliary complications after paediatric liver transplantation: Birmingham's experience

Between 1983 and 1992, 112 children underwent liver transplantation. Of 138 grafts, 60 (43.4%) were whole livers, 77 (55.6%) were reduced livers, and 1 (0.7%) was a split liver. Biliary complications (BC) were defined as any abnormality, even minor, related to the biliary tract. Results were analysed with a minimum follow-up of 9 months. Some 36 grafts (26.1%) in 34 patients (30.4%) presented with BC: bile leaks (17 grafts), biliary obstructions or dilatations (16 grafts), and other complications (3 grafts). Management was mainly surgical with biliary reconstruction via a Roux-en-Y loop. Interventional radiology had an increasing role in recent years. BC were associated with a mortality of 1.8% (2/112), a graft loss rate of 4.3% (6/138), and significant morbidity. Among the various factors whose association with BC was studied, the date of transplantation, the use of reduced grafts and the use of gallbladder conduits appeared to be the main determining factors for BC. From multivariate analysis the use of reduced grafts emerged as the most important factor in reducing BC. We therefore conclude that BC are associated with significant morbidity, but general improvements in both surgical and medical management seem to account for better results in recent years.

Rat heart-aorta cluster transplantation: a novel model to study transplant rejection

The purpose of this study was to develop a microsurgical cluster model of heart plus entire thoracic aorta transplantation and to compare it to the isolated model of heart transplantation as a tool to study transplant rejection. Thirty-six syngeneic (DA x DA and Lew x Lew) and allogeneic (DA x PVG and DA x Lew) cluster heart-aorta transplants were compared to 43 syngeneic and allogeneic isolated heart grafts. Graft survival, recipient survival and histological data on myocardial and aortic tissues were assessed. There was no statistically significant difference in graft survival between the two models studied (P > 0.05). In the cluster transplants, the aortic component was spared the severity of acute rejection noted for the myocardial counterpart. In conclusion, the results demonstrated that the cluster model was technically feasible and highly reproducible. Additionally, it was possible to apply this model to the study of experimental allograft rejection using novel immunosuppressants. The success of the cluster model in strongly mismatched transplant strain combinations underscores its potential for application in slower rejection combinations, making it particularly suited for chronic rejection studies. The inherent capacity for sampling a broader range of vessel sizes in one animal makes the cluster model more suitable than the isolated models of aorta or heart for application to experimental protocols.

Paradoxical blockade of beta adrenergically mediated inhibition of stimulated eosinophil secretion by salmeterol

Salmeterol (SALM) is a long-acting beta 2 adrenoceptor agonist that causes prolonged relaxation of airway smooth muscle. To determine whether this agent also causes prolonged inhibition of stimulated eosinophil secretion, we studied interactions between SALM and albuterol (ALB) in inhibiting eosinophil peroxidase (EPO) secretion in human eosinophils in vitro. Peripheral blood eosinophils were isolated from 18 human volunteers by negative immunoselection, and secretion of EPO was elicited with 10(-6) M formyl-met-leu-phe (fMLP) + 5 micrograms/ml cytochalasin B (CytB) in aliquots of 10(5) cells. Eosinophils were pretreated with either 10(-8) M ALB, 10(-8) M SALM or SALM + ALB for 5 min to 18 hr at 37 degrees C. Pretreatment with ALB for 5 min caused inhibition of stimulated secretion of EPO to 783 +/- 210 ng/10(6) cells vs. 1475 +/- 286 ng/10(6) cells for eosinophils not treated with ALB (P < .05; n = 5). Inhibition of EPO secretion caused by ALB was sustained for 30 min (924 +/- 160 ng/10(6) cells; P < .05 vs. fMLP + CytB; n = 5). By contrast, SALM had no inhibitory effect on fMLP-induced secretion after incubation for 5 min to 18 hr. In cells obtained from four separate isolations, pretreatment with 10(-8)M SALM before addition of ALB blocked the inhibition of EPO release caused by 10(-8)M ALB alone (486 +/- 28 ng/10(6) cells for ALB alone vs. 902 +/- 32 ng/10(6) cells for SALM + ALB; P < .01; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Central processes in gustatory adaptation

In two experiments the adapting stimuli at the periphery of the taste system were of a constant objective intensity but, using mixture suppression and spatial summation, their perceived intensity was varied. The results have shown that, in spite of the constancy in stimulus concentration, the adaptation degree changed with the perceived intensity of the stimulus. The adaptation to the compounds when in binary mixtures proved to be significantly less effective than the adaptation to the same equimolar compounds when unmixed. Similarly, the adaptation effects of solutions of a constant concentration, when applied to a small tongue area, were significantly smaller than when applied to a larger area. This adaptation dependence upon the taste sensation intensity suggests that in the gustatory adaptation, peripheral as well as central processes take part.

Treatment of pain in chronic pancreatitis by inhibition of pancreatic secretion with octreotide

It has been suggested that pancreatic ductal hypertension, secondary to pancreatic outflow obstruction, is a cause of pain in chronic pancreatitis. This study investigated the effect of inhibiting pancreatic secretion with octreotide in chronic pancreatitis pain. Ten patients with chronic alcoholic pancreatitis and severe daily pain were included in an intraindividual double blind crossover study. All patients received octreotide (3 x 100 micrograms/day subcutaneously) and placebo (3 x 0.9% saline solution subcutaneously) for three days at random. Between both treatment phases a two day washout period was interposed. Intensity of pain (visual analogue scale) and analgesic consumption were carefully registered. Pancreatic secretion was monitored daily by measuring faecal chymotrypsin concentration. It was found that during the administration of octreotide, pancreatic secretion was strongly inhibited (faecal chymotrypsin mean (SD) 1.7 (0.6) U/g) with respect to placebo (9.6 (4.2) U/g) and washout (7.6 (3.1) U/g) periods (p < 0.001). Pain score (29.6 (4.5) v 28.7 (5.8)) and consumption of analgesics were no different during the octreotide and placebo periods. It is concluded that short term inhibition of pancreatic secretion does not result in pain relief in patients with chronic pancreatitis. This finding is in contrast with the hypothesis that outflow obstruction of pancreatic secretion with consequent ductal hypertension is an important cause of severe persistent pain in chronic pancreatitis.

Assessment of agonist- and cell-mediated responses in airway microsections by computerized videomicrometry

The objective of this investigation was to develop a method for real-time measurement of changes in luminal area in microexplants of airways during pharmacological and physiological interventions. After guinea pigs were killed, tracheal rings (1- to 2-mm thick) were excised and placed in 300-microliters chambers. The area of the airway lumen was calculated as pixel number with the use of computerized videomicrometry. In 29 epithelium-intact airways, 10(-3) M acetylcholine (ACh) caused decrease in luminal area of 38.1 +/- 2.80% (P < 0.001 vs. 10(-9) M). Spontaneous tone also was demonstrated in 34 preparations from 4 guinea pigs; decrease in area of 17.0 +/- 1.45% after 60-min incubation in buffer alone was blocked completely by 10(-5) M indomethacin (P = 0.01). Luminal narrowing caused by < or = 10(-6) M ACh was reversed completely by 10(-6) M albuterol (P = 0.002). Addition of 100,000 activated human eosinophils caused 24.7 +/- 4.41% decrease in luminal area vs. 7.24 +/- 5.51% for nonactivated cells (P = 0.048). We demonstrate a real-time method for the assessment of auxotonic changes in airway caliber that utilizes microsections of explanted airways and permits the use of extremely small numbers of isolated cells to achieve physiological activation. Concentration-response characteristics and spontaneous tone are similar to those of large chamber preparations, and narrowing is reversed by beta 2-adrenoceptor activation.

Biliary complications after paediatric liver transplantation: Birmingham's experience

Between 1983 and 1992, 112 children underwent liver transplantation. Of 138 grafts, 60 (43.4%) were whole livers, 77 (55.6%) were reduced livers, and 1 (0.7%) was a split liver. Biliary complications (BC) were defined as any abnormality, even minor, related to the biliary tract. Results were analysed with a minimum follow-up of 9 months. Some 36 grafts (26.1%) in 34 patients (30.4%) presented with BC: bile leaks (17 grafts), biliary obstructions or dilatations (16 grafts), and other complications (3 grafts). Management was mainly surgical with biliary reconstruction via a Roux-en-Y loop. Interventional radiology had an increasing role in recent years. BC were associated with a mortality of 1.8% (2/112), a graft loss rate of 4.3% (6/138), and significant morbidity. Among the various factors whose association with BC was studied, the date of transplantation, the use of reduced grafts and the use of gallbladder conduits appeared to be the main determining factors for BC. From multivariate analysis the use of reduced grafts emerged as the most important factor in reducing BC. We therefore conclude that BC are associated with significant morbidity, but general improvements in both surgical and medical management seem to account for better results in recent years.

FK 506 versus cyclosporin in the prevention of renal allograft rejection--European pilot study: six-week results

FK 506 was compared with cyclosporin in a randomised trial in good-risk cadaveric renal transplant recipients. The objective was to evaluate whether oral FK 506 dosing was viable and whether blood concentrations in the range 10-20 ng/ml would prove to be practical. Thirty-one adult patients were randomised to FK 506 and 16 to cyclosporin. Both groups received an identical regimen of azathioprine and corticosteroids. Serum creatinine concentrations decreased rapidly in both groups with mean values below 200 mumol/l within 2 weeks. One graft in the cyclosporin group was lost due to renal vein thrombosis. During the 6-week study period, 19.4% of patients on FK 506 and 31.3% on cyclosporin experienced acute rejection. One patient in each group experienced corticosteroid-resistant rejection that responded to anti-lymphocyte therapy. Infections were reported in 51.6% of the FK 506 group compared with 37.5% of the cyclosporin group. The spectrum of adverse events was similar in both groups. However, minor neurological disorders were more common in the FK 506 group (54.8% versus 6.3%) whereas hypertension was less common (48.8% versus 75.0%). The results indicate that oral FK 506 rapidly achieves therapeutic blood concentrations and is an effective immunosuppressant for the initial treatment of renal allograft recipients.

Differences in expression and intracellular distribution of hexokinase isoenzymes in rat liver cells of different transformation stages

The activity, intracellular distribution and mRNA expression of hexokinase isoenzymes were studied in normal rat liver, and in epithelial liver cells at different stages of neoplastic transformation, including non-tumorigenic and tumorigenic cell lines. In contrast to liver, all transformed cells exhibited only hexokinase I and II, which both showed significantly increased activity, hexokinase II being the more abundant form. In parallel, the mRNA expression of the two isoenzymes was elevated, indicating transcriptional control of gene expression. Hexokinase I and II were found in the cytosol and bound to mitochondrial membranes; the percentage of membrane-bound enzyme activity increased with the grade of transformation from 32% of total activity in normal liver up to 69% in dedifferentiated tumor cells. The ratio of hexokinase I/II was higher in the membrane fraction than in the cytosol. In all tissues studied hexokinase II could be resolved in two subtypes IIa and IIb by hydrophobic interaction chromatography. The relative proportion of cytosolic IIa and IIb varied significantly between normal liver (1:1) and transformed cells, and among cells of different transformation stages (4:1 to 1:10). IIa demonstrated the main activity in the more differentiated, IIb in the less differentiated cell lines. IIa-activity showed a good correlation with the intracellular glucose 6-phosphate concentration of the cells. The data indicate that neoplastic cell transformation is accompanied by progressive alterations in the proportion and subcellular distribution of hexokinase isoenzymes I and II.

Microheterogeneity of cytosolic and membrane-bound hexokinase II in Morris hepatoma 3924A

Phosphorylation of glucose by hexokinase is the key step in glucose and energy metabolism of the cell. In the Morris hepatoma 3924A, hexokinase II is the predominant hexokinase isoenzyme and occurs in the cytosol as well as bound to membranes. Hexokinase II was isolated by DEAE-cellulose chromatography from both the cytosolic and the mitochondria-enriched fractions and further resolved by hydrophobic-interaction chromatography on phenyl-Sepharose into two components designated hexokinase IIa and IIb. In both the soluble and the mitochondria-enriched fractions, type IIb was the predominant form, but the IIb/IIa ratio was higher in the particulate (6-8) as compared with the cytosolic fraction (1.5-2.0). Binding of the isolated forms of the enzyme to rat liver mitochondria resulted in a 2-10-fold activation of both subtypes. Biochemical characterization showed that both subtypes are closely related to the isoenzyme commonly referred to as hexokinase II, and that the microheterogeneity was not a consequence of contamination with hexokinase I or III. Both subtypes had a molecular mass of 110 kDa, they were inhibited by Pi at concentrations higher than 5 mM, and activated by the detergent CHAPS. The two subtypes differed in electrophoretic mobility (IIa > IIb), in Km values for glucose (IIa, 0.109 mM; IIb, 0.216 mM), in Ki values for glucose 6-phosphate (IIa, 25 microM; IIb, 0.106 mM), and in Ki values for glucose 1,6-biphosphate (IIa, 12.2 microM; IIb, 5.5 microM). An artificial proteolytic cleavage as cause of the hexokinase II microheterogeneity can be excluded, since both subtypes show the same molecular mass and the ability to bind to mitochondria and phenyl-Sepharose. In addition, the relative proportions of the two subtypes did not vary markedly between several enzyme preparations. Northern-blot analysis with a hexokinase II-specific cDNA probe revealed two distinct mRNA transcripts of 5.2 and 6.3 kb in length, which offers the possibility that hexokinase II microheterogeneity is due to differential RNA transcription and/or processing.

A nonequilibrium radioimmunoassay for angiotensin II

A method for the measurement of angiotensin II levels in dog plasma is described. The method is similar to previously published assays in that in couples gradient high-performance liquid chromatography (HPLC) with radioimmunoassay (RIA) and requires blood sample collection and processing to plasma in the presence of protease inhibitors. The unique feature of the present method is that it utilized a commercially available angiotensin II RIA run under nonequilibrium conditions. Performing the angiotensin II RIA under nonequilibrium conditions increased RIA sensitivity to allow for a minimal detectable limit of 0.75 pg/mL, a limit of detection not achievable with current commercially available RIAs. This lower limit of detection will now allow for the measurement of circulating levels of angiotensin II. Quality control pools of dog plasma fortified with 4.59-50 pg/mL angiotensin II were assayed and analytical recoveries (ARs) and coefficients of variation (CV) of 72.2%-111% and 3.67%-19.0% were observed for the respective pools.

Pharmacokinetic and pharmacodynamic aspects of an ophthalmic pilocarpine nanoparticle-delivery-system

The regional pharmacokinetics as well as the pharmacodynamics of pilocarpine-loaded nanoparticles for the treatment of glaucoma were investigated and compared to a solution of this drug. Polybutylcyanoacrylate nanoparticles were prepared by an emulsion polymerization process. Formulations with different drug concentrations (2-6%) as well as different particle concentrations were investigated and analyzed for size and drug loading. Drug binding to the particles was achieved at a level of 10-18% of the total drug content. The colloidal nanoparticles were sufficiently small (diameter: 100-300 nm) for a non-irritating application to the eye. All preparations were applied to the eyes of New Zealand white rabbits which were treated with betamethasone before to create an elevated intraocular pressure (IOP). Pilocarpine concentrations, assayed from aqueous humor using gaschromatography, increased by 23% (AUC) for nanoparticle suspensions compared to aqueous reference solutions. Additionally, t1/2 was prolonged and the elimination coefficient was significantly decreased. Pharmacodynamic effects such as miosis and IOP reduction were investigated. tmax values of aqueous humor concentration were observed to be in a similar time range as miosis tmax readings. It was found that at lower drug contents a more pronounced prolongation of miosis was achieved with nanoparticles versus a standard solution. The IOP-reduction was significantly prolonged with nanoparticles preparations; whereas maximum reduction was obtained with a reference solution after 1-2 hours, it was reached with nanoparticles at about 2-3 hours. Differences between nanoparticles and aqueous solutions were most pronounced at lower drug concentrations.

Serum lipids and apolipoproteins in liver transplant recipients: a comparative study of cyclosporin A and FK 506

The immunosuppressive agent cyclosporin A (CsA) is reportedly associated with clinically adverse effects on circulating lipid and apolipoprotein concentrations. To date few data have been reported concerning the effects on lipid metabolism of the new macrolide immunosuppressive agent FK 506, and no comparative studies of the effects of these drugs have been performed. In consideration of the pivotal role of the liver in lipid metabolism, we measured fasting serum lipids and apolipoproteins a median of 8 (range 5 to 9) months after the operation in 20 clinically stable liver transplant recipients randomly allocated to maintenance immunosuppression with CsA +/- azathioprine (n = 10) or FK 506 (n = 10). To avoid the confounding effects of corticosteroids on lipid metabolism, prednisolone was withdrawn at least 6 weeks beforehand in each case. Ten healthy volunteers matched for age and body mass index served as control subjects. Serum total cholesterol concentration was significantly lower in both the CsA (p < 0.001) and FK 506 (p < 0.05) treatment groups when compared with the healthy control subjects. Serum high-density lipoprotein (HDL) cholesterol concentration was also significantly lower in both the CsA (p < 0.005) and FK 506 (p < 0.01) treatment groups. Neither the ratio of serum total cholesterol to HDL cholesterol nor the fasting triglyceride concentrations were significantly different (p > 0.1) from those of the healthy control subjects for either transplant group. Serum apolipoprotein B level was lower than that of the control group in both the CsA (p < 0.005) and FK 506 groups (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Sex differences in dehydroepiandrosterone metabolism in the rat: different plasma levels following ingestion of DHEA-supplemented diet and different metabolite patterns in plasma, bile and urine

Plasma dehydroepiandrosterone (DHEA) and DHEA sulfate levels were determined by an enzyme immunoassay in male and female Sprague-Dawley rats fed a diet containing 0.6% or 0.3% DHEA. A significant difference in DHEA plasma levels was observed in male and female animals. In male rats, total DHEA plasma concentrations were found in the range of 0.4-1.5 microgram/ml (0.6% DHEA chow) and 0.3-0.5 microgram/ml (0.3% DHEA chow). In female animals several times higher DHEA plasma levels were determined: 17.5-33 micrograms/ml (0.6% DHEA chow) and 8.3-14.8 micrograms/ml (0.3% DHEA chow). DHEA was present in rat plasma of both sexes preferably as the sulfate conjugate. Significant sex differences were also found in the DHEA metabolite patterns obtained by TLC separation of extracts from plasma, bile and urine following administration of 3H-DHEA. In female rats, DHEA is present predominantly as the sulfate conjugate in considerable amounts in all materials investigated, whereas in male rats polar metabolites dominate in the patterns.

Can effluent hyaluronic acid or creatine kinase predict sinusoidal injury severity after cold ischemia?

It is well recognized that current selection criteria used to assess liver grafts before implantation are inaccurate and correlate poorly with graft outcome. A bench or laboratory-based test that could indicate the extent of liver injury immediately before implantation would be a valuable adjunct to clinical assessment. Hyaluronic acid (HA) and creatine kinase (BB component; CK-BB) levels in the caval effluent after liver perfusion have been suggested as indicators of preservation injury. Our objective was to investigate the relevance of preserved liver effluent HA and CK-BB as a predictor of early graft function. Perfused liver effluent HA and CK-BB levels were measured. Graft function was measured in terms of peak serum aspartate transaminase and its level on day 5 postoperatively as well as peak bilirubin level and prothrombin time. The cold ischemia time (CIT) was recorded. Statistical comparisons were made among HA level, CK-BB level, CIT, and graft function parameters. The study was conducted at The Liver and Hepatobiliary Unit, Queen Elizabeth Hospital, Birmingham, United Kingdom. Fifty patients undergoing OLT were studied. HA level was measured in 50 patients and CK-BB level in 30 patients. The main outcome measures were graft function and graft outcome. The graft function data are grouped according to effluent HA levels above or below 400 micrograms/L. Thirteen patients (26%) had a level below 400 micrograms/L and the remaining 37 (74%) were above this threshold. There were no significant differences between the groups for these indicators of graft function. There was no difference between the 2 groups for CIT. The overall median HA level was 1212 micrograms/L (range 39-4000 micrograms/L). The median total CK activity in the perfusate was 302 IU/L (range 118-1155 IU/L). The proportion of CK-BB activity from this total was 146 IU/L (8-641 IU/L), or 48% of the total CK activity. In a multiple regression analysis with CK-BB activity as the dependent variable, there was no demonstrable numerical relationship to graft function. In a separate multiple regression analysis similar results were obtained for HA. We conclude that the level of HA or CK-BB levels should not be used in determining the suitability for implantation of a harvested hepatic allograft.

Metabolic effects of cyclosporin A and FK 506 in liver transplant recipients

Postoperative diabetes is a reported feature of the immunosuppressive agents cyclosporin A and FK 506. To date, however, no randomized comparative studies of the metabolic effects of these two drugs have been performed. In this study, extended (300 min) oral glucose tolerance tests (75 g) were performed a median of 8 mo (range 5-9 mo) postoperatively in 20 clinically stable liver transplant recipients randomly allocated to maintenance immunosuppression with either cyclosporin A (with or without azathioprine) or FK 506. None of the patients had clinically overt diabetes antedating transplantation. To avoid the confounding effects of corticosteroids, prednisolone was withdrawn at least 6 wk beforehand in each case. Ten healthy volunteers matched for age and body mass index served as control subjects. Overall blood glucose concentrations after the glucose challenge were significantly elevated in both groups of transplant recipients (P < 0.005 and P < 0.001 for cyclosporin A and FK 506 treatment groups, respectively) compared with the healthy control subjects. Venous whole-blood glucose concentration (mean +/- SE) 120 min after the ingestion of oral glucose was significantly higher in both the cyclosporin A (P < 0.05) and FK 506 (P < 0.01) treatment groups compared with the control subjects (6.6 +/- 0.5 vs. 8.8 +/- 0.9 vs. 5.2 +/- 0.2 mM, respectively). According to 1985 WHO criteria, 4 of 10 cyclosporin A-treated patients had impaired glucose tolerance, whereas 3 of 10 FK 506-treated patients had diabetes with 4 others having impaired glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Subchronic and chronic toxicity of the new sulfonylurea glimepiride in dogs

The new sulfonylurea glimepiride (Hoe 490, CAS 93479-97-1) was tested in subchronic and chronic toxicity studies in dogs. Up to and including a dose of 16 mg/kg b.w. neither toxic effects nor pathological changes were observed in the treated animals. Also at a dose of 320 mg/kg b.w. which was applied over a period of 6 months no undesired effects were detected. However, after a treatment period of 1 year in some of the animals which received 320 mg/kg b.w. cataract formation appeared. The mechanism for that still remains unclear but is not due to changes in special biochemical reactions as it can be observed with other typical cataractogenic chemicals. The relevance of these findings for the application of that drug in humans therefore has to be discussed bearing in mind the extremely high dose and serum levels as well as the number of animals (2/12) where the effects were seen. As expected in all experiments pharmacodynamic effects like reduced serum glucose levels and a degranulation of the beta-cells of the pancreas were seen. Both effects were completely reversible within the recovery period.

Pancreatic cystogastrostomy by combined upper endoscopy and percutaneous transgastric instrumentation

Minimally invasive endoscopic and radiologic techniques have been reported for internal gastric drainage of pancreatic pseudocysts but these have significant technical limitations. A purely endoscopic approach to cystogastrostomy provides limited access for instrumentation and hemostasis. Radiologically-guided percutaneous techniques cannot regularly provide an adequately wide cystogastrostomy opening. Reported is a patient who had a pancreatic cystogastrostomy performed using a minimally invasive surgical approach combining upper endoscopy and percutaneous transgastric surgical instrumentation. The upper endoscope essentially served as a camera. A percutaneous endoscopic gastrostomy tube served as a port for inserting laparoscopic instruments into the stomach. The laparoscopic instruments were used to create a 1.5 cm cystogastrostomy opening similar in size to what could be created by an open abdominal approach. The laparoscopy instruments provided good tactile feedback and excellent hemostatic control. Avoiding an open abdominal procedure shortened postoperative recovery and reduced patient discomfort. Although the pseudocyst recurred once, the same procedure was performed again and there has not been a recurrence for 10 months. The authors conclude that this minimally invasive surgical procedure provides an excellent alternative approach for internal drainage of selected pancreatic pseudocysts.

Application of systematic error bounds to detection limits for practical counting

Overly optimistic estimates of detection limits can result in the use of unrealistic conservatism for decisions about the presence of activity. In some practical counting situations, overly conservative detection limits can result in economically impractical actions. To help preclude such actions, systematic error bounds, uncertainties, and confidence levels can be used when determining critical levels (Lc), detection limits (Ld), and minimum detectable concentrations. This note discusses the selection of such error bounds and the development of detection limit parameters for practical applications. These parameters are shown to be successfully employed in sample activity and measurement process capability decisions for typical counting instruments.

Acute, subchronic and chronic toxicity of the new sulfonylurea glimepiride in rats

Glimepiride (Hoe 490, CAS 93479-97-1) a new sulfonylurea, was tested in acute, subchronic and chronic toxicity studies in rats. The acute toxicity after oral or intraperitoneal administration was very low, all animals survived the maximum administrable dose levels (10,000 mg/kg orally; 3950 mg/kg intraperitoneally). In subchronic and chronic toxicity studies glimepiride was devoid of any significant toxic effects or pathological changes even at high dose levels. Pharmacodynamic effects were present as expected, i.e. decrease in serum glucose levels and degranulation of beta-cells in pancreas.

Essential trace elements in humans. Serum arsenic concentrations in hemodialysis patients in comparison to healthy controls

Serum arsenic concentrations of persons suffering from renal failure and undergoing hemodialysis treatment (n = 85) and of healthy controls (n = 25) were determined by hydride-generation AAS technique after microwave digestion. The results were evaluated by comparing the values of both groups, considering physiological factors and individual data, as well as comorbid conditions of the hemodialysis (HD) patients. Serum arsenic levels were diminished in the patient group compared with controls (mean values 8.5 +/- 1.8 ng/mL vs 10.6 +/- 1.3 ng/mL). Furthermore, additional diseases within the hemodialysis group, particularly injuries of the central nervous system (CNS), vascular diseases, and cancer, were correlated to occasionally markedly decreased serum arsenic concentrations. It was concluded that arsenic homeostasis is disturbed by HD treatment and certain additional diseases. Desirable arsenic concentrations in the body seem to be reasonable. This consideration results in the conclusion that arsenic could play an essential role in human health. Thus, reference arsenic concentrations in different human tissues and body fluids should be established in order to recognize not only arsenic intoxication, but also arsenic deficiency. Perhaps arsenic deficiency contributes to the increased death risk of HD patients, and therefore, arsenic supplementations for patients with extremely low serum arsenic concentrations should be taken into account.

[The value of ultrasound and computerized tomography in detection of cystic changes in chronic pancreatitis]

Intra- or extrapancreatic pseudocysts (PP) are the most common local complication in chronic pancreatitis. Aim of this study was to investigate frequency, localisation and size of pseudocysts in patients with chronic pancreatitis by means of ultrasound (US) and computed tomography (CT). 155 patients (females 35, males 120) with chronic pancreatitis, that underwent simultaneous (within two weeks) CT and US examinations, from January 1982 to June 1989, were included in this study. Cystic lesions were detected in 62% by CT, in 52% by US. Sensitivity in detection of cysts based on intraoperative findings (gold standard) was 98% for CT and 94% for US. 80% of the pseudocysts were smaller than 6 cm. 46% were in the range from 2 to 66 cm and 34% were smaller than 2 cm. The most common localisation was the pancreatic head region (50%), 20 of 102 patients with chronic pancreatitis were found to have a direct communication of a pseudocyst with the ductal system by ERP. No specific clinical or laboratory pattern were associated with the presence of pseudocysts. Increased pancreatic serum amylase concentration was detected in 29% of patients with and in 27% of patients without pseudocysts.

Ventilatory and metabolic responses to acute hyperoxia in newborns

Hyperoxia has previously been found to increase metabolic rate (oxygen consumption [VO2] and CO2 production [VCO2]) in newborn mammals. We asked whether the same occurs in the newborn infant. Breathing pattern was measured in 25 full-term infants, 1 to 2 days of age, from the spirometric record obtained with a pneumotachograph attached to a face mask. Concentrations of O2 and CO2 were continuously measured at the mouth; VO2 and VCO2 were computed as the product of VE and the difference between inspired and expired concentration of the respective gases, 5 min of air (FIO2 = 0.21) and 5 min of O2 (FIO2 = 1). A bias flow through the mask and pneumotachograph delivered the inspired gas and eliminated the effects of the instrumental dead space. In neither case did measurements at 1 min significantly differ from those taken at 5 min. In hyperoxia VE increased in 22 of the 25 infants, in average +18% (p less than 0.001, paired two-tailed t test). Because of a rise in tidal volume (+35%, p less than 0.001) and a decrease in breathing rate (-11%, p less than 0.005) alveolar ventilation (VA) increased by about 58% (p less than 0.001). VO2 and VCO2 increased by 25% and 17%, respectively (p less than 0.001). The rise in VO2 was too large to be explained by the greater respiratory work of the hyperventilation, whereas that of VCO2 was not large enough to fully explain the increase in VA. We conclude that in newborn humans, as in other newborn species, the normoxic metabolic rate seems to be limited by the availability of O2.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospital design of the future--healing environments

Predicting the future of hospital design is hardly a consensus forming art. Crystal ball visions of the 21st-century hospital vary from expert to expert. Perhaps that's simply a sign of the diversity of our health care system. Or perhaps it's a problem inherent in reading the future. For example, some hospital architects and facility planners say tomorrow's hospitals will be smaller due to technological advances. Others say those same advances will create larger hospitals brimming with high-tech equipment. Some say hospitals will be part of medical malls; others see them in a campus setting, perhaps accompanied by satellite facilities in the surrounding community. Yet, despite their often diverse views of the future, architects and planners do share common thoughts about hospital architecture in the decades ahead. Without question, they most commonly agree that hospitals will offer a more patient-friendly environment. Achieving that goal could take many forms, but it is expected to include the use of soothing colors, attractive landscaping, natural lighting, wayfinder lobbies and entrances, private rooms, quieter hallways and accommodations for family and friends.

The nucleotide sequence of rat liver glycogen phosphorylase cDNA

The nucleotide sequence of a cDNA coding for rat liver glycogen phosphorylase has been determined. The 2715 base pairs of the cDNA are sufficient to encode the total protein as determined by comparison with the liver type of glycogen phosphorylase of man. Human and rat liver glycogen phosphorylase showed 86% homology at the DNA level whereas the deduced amino acid sequence has 93.5% identity.

Toxicity of cefpirome: an overview

Cefpirome is a new cephalosporin antibiotic with a broad antimicrobial spectrum in vitro. This includes strains which are frequently resistant to other cephalosporins (Seibert et al., 1983). This report gives a summary of the toxicological investigations on cefpirome.