Cholecystokinin-induced protection against gastric injury is independent of endogenous somatostatin

Cholecystokinin (CCK) prevents macroscopic injury to the stomach from luminal irritants by an unknown mechanism. The present study was undertaken in conscious rats to ascertain what role gastric mucosal blood flow, sensory neurons, and endogenous somatostatin play in CCK-induced gastric protection. Subcutaneous administration of CCK (10-100 micrograms/kg) significantly reduced macroscopic injury to the acid-secreting portion of the stomach caused by 1 ml of orally administered acidified ethanol (150 mM HCl, 50% ethanol) and augmented gastric mucosal blood flow (fluorescent microspheres) in a dose-dependent fashion. However, although the protective response to CCK (100 micrograms/kg) was still present at 2 h, the blood flow response had returned to baseline by 45 min. Ablation of capsaicin-sensitive afferent neurons with capsaicin (125 mg/kg sc) did not negate CCK-induced protection. Pretreatment with exogenous somatostatin (1 pmol-1 nmol/kg sc) failed to prevent the damaging effects of acidified ethanol to gastric mucosa. Immunoneutralization of endogenous somatostatin with somatostatin monoclonal antibody (2 mg ip) did not reverse the protective actions of CCK. Thus the data suggest that although CCK may prepare the gastric mucosa to withstand a damaging insult by augmenting gastric mucosal blood flow, its protective mechanism is independent of intact sensory neurons and endogenous somatostatin.

Effects of the selective bisindolylmaleimide protein kinase C inhibitor GF 109203X on P-glycoprotein-mediated multidrug resistance

Inhibition of protein kinase C (PKC) is discussed as a new approach for overcoming multidrug resistance (MDR) in cancer chemotherapy. For evaluation of this concept we applied the bisindolylmaleimide GF 109203X, which shows a highly selective inhibition of PKC isozymes alpha, beta 1, beta 2, gamma, delta and epsilon in vitro. The efficacy of this compound in modulation of MDR was examined using several P-glycoprotein (P-gp)-overexpressing cell lines including a MDR1-transfected HeLa clone, and was compared with the activities of dexniguldipine-HCI (DNIG) and dexverapamil-HC1 (DVER), both of which essentially act via binding to P-gp. As PKC alpha has been suggested to play a major role in P-gp-mediated MDR, cell lines exhibiting different expression levels of this PKC isozyme were chosen. On crude PKC preparations or in a cellular assay using a cfos(-711)CAT-transfected NIH 3T3 clone, the inhibitory qualities of the bisindolylmaleimide at submicromolar concentrations were demonstrated. At up 1 microM final concentrations of the PKC inhibitor GF 109203X, a concentration at which many PKC isozymes should be blocked substantially, no cytotoxic or MDR-reversing effects whatsoever were seen, as monitored by 72 h tetrazolium-based colorimetric MTT assays or a 90 min rhodamine 123 accumulation assay. Moreover, depletion of PKC alpha by phorbol ester in HeLa-MDR1 transfectants had no influence on rhodamine 123 accumulation after 24 or 48 h. MDR reversal activity of GF 109203X was seen at higher final drug concentrations, however. Remarkably, [3H]vinblastine-sulphate binding competition experiments using P-gp-containing crude membrane preparations demonstrated similar dose dependencies as found for MDR reversion by the three modulators, i.e. decreasing efficacy in the series dexniguldipine-HCl > dexverapamil-HCl > GF 109203X. Similar interaction with the P-gp in the micromolar concentration range was revealed by competition of GF 109203X with photoincorporation of [3H]azidopine into P-gp-containing crude membrane preparations. No significant effect of the PKC inhibitor on MDR1 expression was seen, which was examined by cDNA-PCR. Thus, the bisindolylmaleimide GF 109203X probably influences MDR mostly via direct binding to P-gp. Our work identifies the bisindolylmaleimide GF 109203X as a new type of drug interacting with P-gp directly, but does not support the concept of a major contribution of PKC to a P-gp-associated MDR, at least using the particular cellular model systems and the selective, albeit general, PKC inhibitor GF 109203X.

Secondary interlocking nailing of previously infected nonunion of the tibia

Secondary interlocking nailing was performed in a series of 25 cases of uninfected, but previously infected nonunion of the tibia because of delayed bone consolidation or persisting nonunion. The primary treatment for the originally infected nonunion consisted of radical debridement, removal of alloplastic implants and sequestrated bone fragments, implantation of Gentamicin-PMMA chains(1) for local antibiotic therapy, re-osteosyenthesis with an external fixator. Bone grafting was performed after eradication of the infection. In two patients free muscle transfer with microvascular anastomosis became necessary to improve the soft tissue situation before bone grafting. Gentamicin-PMMA sticks with antibiotic activity similar to the Gentamicin-PMMA chains were inserted into the lumen of the nails as a prophylactic measure to prevent reinfection after nailing.

RESULTS

In 22 patients complete bone consolidation was achieved without recurrence of infection. In two patients with late recurrence of infection but incomplete bone consolidation, the implant was removed and an orthopaedic brace was applied temporarily. In one patient with early recurrence of infection with a highly resistant strain of Staph. aur. removal of the nail became necessary, followed by re-osteosyenthesis with an external fixator, systemic antibiotic therapy and secondary bone grafting.

A flow sheet for follow-up after chemotherapy extravasation

PURPOSE/OBJECTIVES

To introduce and describe the development and implementation of a flow sheet used to document patient follow-up after chemotherapy extravasation.

DATA SOURCES

Published articles, institutional standards of nursing practice, and the Oncology Nursing Society Cancer Chemotherapy Guidelines.

DATA SYNTHESIS

Extravasation is a potentially serious and severe complication of vesicant chemotherapy administration. A tool was designed to streamline documentation of patient symptoms, nursing interventions, patient education, and follow-up care after a suspected or actual extravasation.

CONCLUSIONS

The flow sheet improves nursing documentation after a suspected or actual vesicant chemotherapy extravasation and provides a consistent, concise method for monitoring extravasations over time.

IMPLICATIONS FOR NURSING PRACTICE

The flow sheet standardizes nursing assessment, intervention, patient education, and follow-up care after a suspected or actual chemotherapy extravasation. Use of the flow sheet saves time and improves consistency of nursing documentation.

B9209-005, an azido derivative of the chemosensitizer dexniguldipine-HCl, photolabels P-glycoprotein

P-glycoprotein is an energy-dependent drug extrusion pump for a variety of anticancer drugs and is involved in the development of multidrug resistance in cancer. Dexniguldipine-HCl is a potent chemosensitizer for P-glycoprotein-mediated multidrug resistance in vitro, and clinical phase I/II trials are underway. To investigate the mechanisms of chemosensitization and to identify the binding sites for dexniguldipine-HCl on target proteins involved in chemosensitization, [3H]B9209-005, an azido derivative of dexniguldipine-HCl, was synthesized and used as a photoaffinity ligand. In two models of multidrug resistance reversal, i.e., sensitization to vincristine and modulation of rhodamine-123 uptake, B9209-005 and dexniguldipine-HCl showed identical biological activities. Photoaffinity labeling experiments with [3H]B9209-005 in cell membranes from multidrug-resistant CCRF ADR-5000 cells, in comparison with labeling experiments with [3H]azidopine (an established photoaffinity ligand for P-glycoprotein), showed that [3H]B9209-005 labeled two proteins, with apparent molecular masses of 170 and 95 kDa. The pharmacological specificity of labeling was demonstrated by inhibition of photoincorporation by several cytostatic drugs transported by P-glycoprotein, as well as by chemosensitizers. Immunoprecipitation of the labeled proteins with the P-glycoprotein-specific monoclonal antibody C 219 and with a site-directed polyclonal antibody to the amino-terminal sequence of P-glycoprotein (amino acids 389-406) identified these proteins as intact P-glycoprotein and the amino-terminal fragment thereof. No specific labeling was obtained in the drug-sensitive parent cell line CCRF-CEM, which is devoid of significant P-glycoprotein expression. Maximal labeling of 17 pmol of the 170-kDa protein/mg of crude membrane protein was obtained. The affinity of [3H]B9209-005 for binding to and photoincorporation into P-glycoprotein was 5-fold greater than that of [3H]azidopine, and photoincorporation of [3H]B9209-005 showed a different photoincorporation pattern, compared with [3H]azidopine, in that the latter compound was incorporated specifically into the carboxyl-terminal 55-kDa fragment of P-glycoprotein. In contrast to [3H]azidopine, no specific labeling of this fragment was obtained with [3H]B9209-005, indicating different binding sites for or different photoincorporation of the two dihydropyridine ligands. Because B9209-005 carries the photoreactive azido group in the dihydropyridine moiety, whereas the azido group of azidopine is located in the side chain, these results suggest that the dihydropyridine moiety of the two compounds probably interacts with the amino-terminal part of P-glycoprotein, whereas the side chains react preferentially with the carboxyl-terminal 55-kDa fragment.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemorrhagic shock increases gut macromolecular permeability in the rat

The effect of hemorrhagic shock on gut permeability to macromolecules was investigated using fluorescein isothiocyanate dextrans (4,300 or 73,100 daltons). These were given orally, then measured in systemic blood during hemorrhage (mean arterial pressure of 30 mmHg) and reperfusion; sham-shocked animals served as controls. Hemorrhage lasting 2 h resulted in a 5-fold increase in concentration of both tracers relative to that found in control groups. Reperfusion reduced these differences, with values approximately threefold greater than those of controls after 2 h. On a molar basis, the smaller molecule was more permeant than the larger one. This study provides evidence that hemorrhagic shock physically perturbs the normal barrier function of the mucosa, permitting very large substances in the gut lumen access to the circulation. It may further explain, at least in part, previous observations that hypovolemic shock results in bacterial translocation and endotoxemia.

Use of antibiotic-PMMA beads in the ischemic foot

Thirty-six patients with 44 ischemic foot infections were managed with antibiotic-polymethylmethacrylate (PMMA) beads. Most of these patients received gentamicin-impregnated PMMA beads but tobramycin and vancomycin-impregnated PMMA beads were used on three patients. Angiopathy occurred in 35 patients secondary to diabetes and secondary to renal disease in 2; 1 patient had both diabetes and renal disease. The most common bacteria was Staphylococcus aureus (82%), although other organisms and multiple bacteria were present. In spite of the variability of the bacteria, PMMA beads were helpful in managing foot infections in this difficult patient population.

Primary structure differences of human surfactant-associated proteins isolated from normal and proteinosis lung

The primary structures of human pulmonary surfactant-associated proteins SP-A, SP-B and SP-C isolated from lung lavage of patients with alveolar proteinosis exhibit significant differences from lung surfactant proteins isolated from lungs of healthy individuals. In contrast to SP-A from normal lungs, proteinosis SP-A was shown by SDS gel electrophoresis to contain large amounts of unreducibly cross-linked beta chains. Specific primary structure modifications of SP-C and SP-B proteins were established by direct molecular weight and structural analysis, using [252Cf]plasma desorption mass spectrometry (PD/MS) as the principal method. In comparison to normal lung surfactant SP-B, proteinosis SP-B showed a significantly increased molecular weight by approx. 500 Da for the unreduced protein dimer. SP-C proteins from normal lungs were identified to possess a bis-cysteinyl-5,6-(thioester)palmitoylated structure, and to contain a frayed N-terminus resulting in two sequences of 34 and 35 amino acid residues. In contrast, SP-C from proteinosis patients was modified by (i) partial or even complete removal of palmitate residues and (ii) additional N-terminal proteolytic degradation. These results indicate the presence of pathophysiological structure modifications, which are likely to occur in the alveolar space, and may lead to a reduced surfactant function.

(H+,K+)-ATPase inhibiting 2-[(2-pyridylmethyl)sulfinyl]benzimidazoles. 4. A novel series of dimethoxypyridyl-substituted inhibitors with enhanced selectivity. The selection of pantoprazole as a clinical candidate

[(Pyridylmethyl)sulfinyl]benzimidazoles 1 (PSBs) are a class of highly potent antisecretory (H+,K+)-ATPase inhibitors which need to be activated by acid to form their active principle, the cyclic sulfenamide 4. Selective inhibitors of the (H+,K+)-ATPase in vivo give rise to the nonselective thiophile 4 solely at low pH, thus avoiding interaction with other thiol groups in the body. The propensity to undergo the acid-catalyzed transformation is dependent on the nucleophilic/electrophilic properties of the functional groups involved in the formation of 2 since this step is both rate-determining and pH-dependent. The aim of this study was to identify compounds with high (H+,K+)-ATPase inhibitory activity in stimulated gastric glands possessing acidic pH, but low reactivity (high chemical stability) at neutral pH as reflected by in vitro (Na+,K+)-ATPase inhibitory activity. The critical influence of substituents flanking the pyridine 4-methoxy substituent present in all derivatives was carefully studied. The introduction of a 3-methoxy group gave inhibitors possessing a combination of high potency, similar to omeprazole and lansoprazole, but increased stability. As a result of these studies, compound 1a (INN pantoprazole) was selected as a candidate drug and is currently undergoing phase III clinical studies.

[Closure of soft tissue defects in bone infections using free and pedicled muscle flaps]

Over the period of three years 33 free latissimus dorsi-flaps and 23 pedicled myoplasties of various types for the coverage of large tissue and bone defects are performed. The operative technique of the free muscle transfer with microvascular anastomosis are described in detail. The postoperative management is outlined. The results of the free and pedicled muscle flaps are reported. In free transplantations the success-rate was 88% and in pedicled flaps 65% There is good evidence that bone consolidation and healing of the chronic bone infection can be improved by healthy vital soft tissue coverage. The indications for both procedures and the advantages and disadvantages of free and pedicled flaps are discussed.

[The social environment and consequences in patients with posttraumatic osteomyelitis]

As soon as the extent of damage--especially in infected nonunion with substantial bone defect--becomes clinically apparent, the patient should be fully informed about the possibilities of treatment, which functional result can be expected in an attempt to salvage the extremity and the implications of long-term hospitalization with the necessity for multiple operations on the patient's social and professional rehabilitation. The patient may then decide for himself that early amputation will give him much better chances in his future life.

[Treatment of chronic osteomyelitis with gentamicin PMMA chains]

In the treatment of chronic osteomyelitis radical removal of sequestrated bone fragments is of essential importance. Any antibiotic therapy - whether systemically or locally applied - can only be a supplementary measure. By implantation of gentamicin-PMMA-chains into infected cavities high local concentrations of the antibiotic can be achieved which are far above the minimal bactericidal concentrations of most common pathogens. As result of the very low concentrations of gentamicin in the serum and urine there is no hazard of nephrotoxicity and ototoxicity. Chronic sequestrating osteosyntheses and infected non-unions are the most important indications for the application of gentamicin-PMMA-chains.

The sulphoxide moiety of substituted benzimidazoles is essential for inhibition of parietal cell K+/H+-ATPase

The antisecretory action of the benzimidazole sulphoxide derivative B 823-10, 2[(4-methoxy-3-methyl-2-pyridylmethyl)-sulphinyl]- 5-trifluoromethyl(1H)-benzimidazole, was compared with the effect of the corresponding sulphide B 823-08 in several in vivo and in vitro and in vitro test systems. The sulphide B 823-08 and the sulphoxide B 823-10 were found to be equipotent in the Shay rat. The sulphide was found to inhibit H+ secretion in intact rabbit gastric glands and enriched guinea-pig parietal cells with lower potency than the corresponding sulphoxide. The relative potency in antisecretory activity (sulphide/sulphoxide) decreased in the following rank order: Shay rat: gastric glands: parietal cells. Purified K+/H+-ATPase was not blocked by the sulphide, whereas the sulphoxide inhibited the overall as well as the partial reactions of this enzyme. In all in vitro systems tested, inhibition of H+ secretion and enzyme activity by the sulphoxide, but not by the sulphide, was antagonized by SH-compounds such as dithiothreitol. It is concluded that in vivo sulphoxidation of the sulphide plays an important role in acid inhibition. In vitro an additional inhibitory mechanism of the sulphide has to be considered.

Dipeptidyl peptidase IV and alpha-naphthylacetate esterase in human T lymphocytes: cytochemical and biochemical investigations

Dipeptidyl peptidase IV (DP IV) activity of human lymphocytes was measured using biochemical assays of cell suspensions and enzyme cytochemical staining of smears from capillary blood and mononuclear cells (MNC). The hydrolysis rate of Gly-Pro-pNA in suspensions of MNC correlates well with the number of DP IV reactive cells as determined by cytochemical staining. MNC from healthy volunteers were shown to contain 44 +/- 10% lymphocytes reactive for DP IV. Using preparations of T lymphocytes and adherent MNC it was shown that DP IV is specific for T lymphocytes. About 60% of T lymphocytes contain DP IV and 94% of DP IV reactive cells form rosettes with sheep erythrocytes. Parallel staining for DP IV and unspecific acid alpha-naphthylacetate esterase (ANAE) yielded nearly the same figure of cells stained for ANAE in a dot-like pattern (50 +/- 10% MNC) as was observed for DP IV. Correlation of both markers indicates that DP IV expressing lymphocytes presumably represent that subpopulation of TM cells which is characterized by a dot-like reaction pattern of ANAE.

[Indication, technic and results using the external fixator in infected fractures and infected pseudarthrosis]

Infected pseudo-arthrosis is the dreaded combination of chronic osteomyelitis and instability at the fracture site. Treatment consists in radical removal of sequestered bone and alloplastic implants, temporary implantation of Septopal chains for high-dose local antibiotic therapy and re-osteosynthesis with external fixator. The external fixator of Raoul Hoffmann is preferred because of its unlimited versatility. A total of 131 patients were treated in accordance with the method described. In 90.1% of the cases bone consolidation was achieved, and in 89.3% chronic osteomyelitis subsided.

[The fall of Icarus or the seriously injured young motorcyclist (author's transl)]

During 1979 70 motorcyclists were treated in the Department of Traumatology of the "Berufsgenossenschaftliche Unfallklinik" Frankfurt/Main. The psychological reasons of the motorcycle-boom and the consequences are compared. The psychic status of these young motorcyclists was different from that of other patients. An analysis of the data showed that in 24.3% the accident occurred on the way to work or to school; 75.7% of the accidents happened during a pleasure-trip. 58.6% of the motorcyclists suffered injuries with permanent sequels. The different types of permanent damage are described. Based on two case reports the arising costs are analysed.