A comparative study of ceftriaxone plus amikacin, ceftazidime plus amikacin and imipenem/cilastatin in the empiric therapy of febrile granulocytopenic cancer patients

In a prospective, randomized study we compared ceftriaxone (active ingredient of Rocephin) plus amikacin, ceftazidime plus amikacin and imipenem/cilastatin in the empiric therapy of febrile granulocytopenic (less than 500/mm3) patients with cancer or aplastic anemia. Of 27 evaluable episodes, 12 were treated with ceftriaxone plus amikacin, 5 with ceftazidime plus amikacin and 10 with imipenem/cilastatin. 56% were culture-positive. Septicemia was the most frequent site of infection and Escherichia coli was the most frequently isolated organism. The efficacy of the three regimens was comparable. One failure occurring in each treatment group was successfully treated with an alternative antibiotic regimen. A second failure in the first treatment group did not respond to the alternative treatment either. No major adverse effects occurred. This study demonstrates that the three regimens are excellent in the empiric therapy of febrile granulocytopenic patients.

Clostridium perfringens septicemia with massive hemolysis

Massive hemolysis with acute renal failure occurred in a previously healthy 69-year-old patient as a complication of Clostridium perfringens septicemia secondary to gall bladder empyema. To our knowledge, this is one of the few patients with C. perfringens septicemia and massive intravascular hemolysis who survived the episode and regained a normal renal function.

Ludwig's angina: an analysis of 14 cases

Ludwig's angina remains a potentially lethal disease entity as it causes rapidly progressive airway obstruction, although the current mortality rate is low. Early surgical intervention should be carried out in severe cases which show signs of fluctuation, abscess formation or other serious complications. We report our experience with 14 cases of Ludwig's angina, 12 of which (86%) were of dental origin. Only one case was complicated with Klebsiella pneumoniae septicemia which resolved upon treatment. There were no deaths. Surgical procedures including incision and drainage and tooth extraction were performed in 11 cases (78%). Antibiotics were administered to all patients. Most of them were treated with crystalline penicillin with or without an aminoglycoside. Only one patient received a tracheostomy in this series. The number of tracheostomies or intubations carried out was much lower than in previous reports. We suggest that an aggressive antimicrobial therapy, early surgical intervention and careful monitoring of the respiratory symptoms would reduce both the need for tracheostomy and the mortality rate.

Differential effects of mercurial and methylmercurial ions on the phrenic nerve and diaphragm of the mouse

Both Hg2+ and CH3Hg+ exert a depressive action on the twitch amplitude elicited by nerve stimulations more rapidly than that by muscle stimulation. CH3Hg+ was relatively more potent than Hg2+ in the nerve depressive action but was weaker on the muscle. Hg2+ induced a rapid phase and a slow phase of contracture in the diaphragm, while CH3Hg+ induced only a slow one. The biphasic contracture induced by Hg2+ could be inhibited by repetitive washout of the diaphragm with low Ca2+ (10(-3) mM) Krebs and also by treatment with glycerol to close T-tubule, while the slow contracture induced by CH3Hg+ was little affected by glycerol treatment. None of denervation, d-tubocurarine and tetrodotoxin inhibited the contracture induced by Hg2+ and CH3Hg+, indicating that the contracture was induced by a direct action on the muscle. Hg2+, but not CH3Hg+, rapidly caused a decrease of the membrane potential, decreased the amplitude and prolonged the duration of the muscle action potential. Hg2+ also initially decreased and then increased 45Ca2+ uptake of the diaphragm, but CH3Hg+ had no effect, except a prolonged incubation at a high concentration. The action of Hg2+ could be antagonized by glutathione, and CH3Hg+ was more susceptible than Hg2+ to the antagonistic action of glutathione. Both Hg2+ and CH3Hg+ did not change the ATP content of the diaphragm. All of these findings indicate that the monovalent organic CH3Hg+, with a higher lipophilicity, possesses a higher affinity to the nerve while the divalent cationic Hg2+ exerted more effects than CH3Hg+ on the sarcolemma of the mouse diaphragm.

Relationship between radioprotective and neuromotor effects of S-2(3-aminopropyl-amino)ethylphosphorothioate (WR-2721) in mice

The radioprotective and neuromotor effects of WR-2721 were studied in male albino ICR strain mice. The protective activity was evaluated by graded doses of WR-2721 (50-400 mg/kg, IP) against whole body 60Co gamma irradiation at a single maximal lethal threshold dose rad (i.e., 1250 rad). The neuromotor effects of the drug were assayed by its action, at the same dose range as used in the protection assay, on spontaneous motor activity (SMA) and wire hanging performance (WHP). Drug doses were administered 30 min before radiation exposure and neurobehavioral testings. The results showed a dose-dependent increase in radioprotection and an inhibition in the neuromotor tasks. The radioprotective efficacy was seen at doses at which intrinsic neuromotor deficits were detected (100-400 mg/kg). A dose-related parallelism of protective efficacy and neurobehavioral toxicity (i.e., SMA inhibition and WHP disruption) was also observed. The present findings suggest that WR-2721 induces neuromotor dysfunctions along with its radioprotectivity.

Survey of periodontal disease among workers in Tianjin using Ramfjord's Periodontal Disease Index (PDI)

An epidemiologic study of periodontal disease according to Ramfjord's PDI among 2284 workers was performed in Tianjin in 1982. This study included 1066 men and 1218 women, aged 18-50. The prevalence of gingivitis and periodontitis was 89.5% and 44.4%, respectively. Only 28 workers were free from periodontal disease. Gingivitis and periodontitis were highly prevalent in both sexes, but men had more severe gingivitis and periodontitis than women. The better oral hygiene of the women may account for this difference.

Immunologic identification of the cleavage products from the A alpha- and B beta-chains in the early stages of plasmin digestion of fibrinogen

Fragment X components (Mr 225,000 to 333,000) were distinguished on sodium dodecyl sulfate polyacrylamide gels. Western blotting with monoclonal antibodies to A alpha-chain segments demonstrated that the A alpha-chains of fibrinogen and the largest fragment X components (Mr 285,000-340,000) contained both A alpha 259-276 and A alpha 540-554. Fragment X components of Mr 270,000-285,000 contained A alpha 259-276 but lacked A alpha 540-554, whereas the smallest fragment X components (Mr 225,000-270,000) contained neither A alpha 540-554 nor A alpha 259-276. Studies of the small peptides generated during fragment X formation complemented the studies of the large molecules, by demonstrating peptides containing both A alpha 259-276 and A alpha 540-554 (Mr 41,600-41,800 and Mr 38,700-38,900), peptides containing A alpha 540-554 but not A alpha 259-276 (Mr 20,500-21,000 and Mr 17,300-17,500) and peptides containing only A alpha 259-276 (Mr 23,600-24,000 and Mr 20,500-21,000). Cleavage of B beta 1-42 from the amino terminal ends of the B beta-chains, measured with a specific radioimmunoassay, was linear until 1.6 moles per mole of fibrinogen had been released, and coincided with loss of the central and carboxy terminal A alpha-chain regions, i. e. A alpha 259-276 and A alpha 540-554. Based on present and previously reported data, a model is proposed for the evolution of the heterogeneous group of fragment X derivatives from fibrinogen with the simultaneous release of small peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetic studies and structure-activity relationships of bispyridinium oximes as reactivators of acetylcholinesterase inhibited by organophosphorus compounds

The kinetics of the reactivation of acetylcholinesterase inhibited by isopropyl methylphosphonofluoridate was studied. The reactivators used include nine bispyridinium monooximes and three bispyridinium dioximes. The dissociation constant (Kd) and the rate constant (k2) of dephosphorylation of the complex formed from the organophosphorus acetylcholinesterase (OP-AChE) and the oxime were measured. The reactivation parameters obtained from the in vitro kinetic studies were used to elucidate the structure-activity relationships. The hydrophobic property of a nonoxime substituent at the 3-position on the pyridinium ring can exert a positive effect on their binding affinity to OP-AChE. However, the rate constants (k2) of the nucleophilic displacement of OP-AChE by oximes depend negatively on these physical and structural factors of the oximes. The correlations of the in vivo antidotal efficacy (ED50) of these bispyridinium oximes have been analyzed with their pharmacological properties, e.g., reactivation potency, antimuscarinic activities, and antinicotinic activities. However, no satisfactory correlations were observed. It may be concluded that the detoxication mechanism of poisoning by isopropyl methylphosphonofluoridate is different from those of pinacolyl methylphosphonofluoridate and paraoxon.

Gold labeling of thrombin and ultrastructural studies of thrombin-gold conjugate binding by fibrin

Monodispersed thrombin-gold (T-Au) conjugates were prepared by the absorption of a monolayer (3.8 nm thick) of human alpha-thrombin around individual monodispersed colloidal gold particles (16.5 +/- 1.8 nm). Like free molecular thrombin, T-Au conjugates can cause platelet aggregation, plasma clotting, and the release of fibrinopeptides A and B from fibrinogen. At the same thrombin concentration, T-Au conjugates have only one-tenth the fibrinogen-clotting activity of free thrombin and one-third the amidolytic activity of free thrombin. Hirudin can completely inhibit the fibrinogen-clotting activity of both T-Au conjugates and free thrombin, but can inhibit only half of the amidolytic activity of the conjugates. Diisopropyl fluorophosphonate can completely inhibit the fibrinogen-clotting activity and the amidolytic activity of both T-Au conjugates and free thrombin. T-Au conjugates were further characterized by studying the mechanism of their binding to fibrin and the location of the binding site on fibrin. The results of electron microscopic studies showed that T-Au conjugates, but not albumin-Au conjugates, are bound by fibrin. Increasing T-Au conjugate concentrations are associated with an increase in the number of T-Au conjugates binding to fibrin. At 0.1 microM thrombin, 73% of the T-Au conjugates are bound to branch points of the fibrin network with 27% of the T-Au conjugates present in the fibrin strands. At higher thrombin concentration (e.g., 0.5 microM) the percentage of T-Au conjugates bound to locations other than branch points increases to 62%.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of fibrinogen New York 1. A dysfunctional fibrinogen with a deletion of B beta(9-72) corresponding exactly to exon 2 of the gene

Fibrinogen New York 1 (NY-1) was identified in a family with a thrombotic tendency. Studies on fibrinogen NY-1 and the fibrinogen from her brother, designated NY-1a, showed that both have abnormal thrombin-nonclottable fibrinogen (50% of the total fibrinogen in NY-1 and 35-40% in NY-1a) and that the trait is heterozygous and autosomal codominant. The abnormal fibrinogen polymerizes in the presence of calcium and can be further cross-linked by Factor XIIIa. The release rates of fibrinopeptides A and B by thrombin from both (NY-1 and NY-1a) were slower than those from normal fibrinogen. Two mol of fibrinopeptide A but only 0.6-1.0 (NY-1) or 1.0-1.3 (NY-1a) mol of fibrinopeptide B were released per mol of fibrinogen. Additionally, only 1.0 (NY-1) or 1.3 (NY-1a) mol of the B beta(1-42) peptide were released by plasmin/mol. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the reduced fibrinogen revealed two protein bands in the B beta-chain region (Mr = 54,000 as compared with 57,300 for the normal). When NY-1a fibrinogen was treated with CNBr, two sizes of the NH2-terminal disulfide knot were obtained (Mr = 59,000 and 49,000). The Mr = 49,000 component is consistent with an abnormal NH2-terminal disulfide knot with two defective NH2-terminal B beta-chains. Amino acid sequence analyses demonstrated that the abnormal B beta-chain is the result of a deletion in the sequence from residues 9 to 72. This deletion corresponds exactly to exon 2 of the gene. Since this family has a thrombotic tendency, the defect in the fibrinogen may be important in the pathogenesis of thrombosis in this family.

Adverse behavioral effects of the anticholinesterase poisoning protector pralidoxime methanesulfonate

Pralidoxime methanesulfonate (P2S) has anticholinesterase protective properties, but it also has an array of gastrointestinal (GI) symptoms. Because such a symptom would be disadvantageous to occupational workers who handled and used organophosphorus anticholinesterase continuously, and to soldiers who have had oral pretreatment in a situation where anticholinesterase agent poisoning is a possibility, this question was investigated in rats using three behavioral paradigms to evaluate the feasibility of the oral prophylactic regimen. These are: (1) conditioned taste aversion (CTA), (2) operant behavior and (3) spontaneous locomotor activity (SMA); these three behavioral parameters are analogous to toxicant-induced gastrointestinal (GI) disturbances, performance of learned tasks and behavioral arousal, respectively. Dose-response studies of P2S in dose levels of 0.2, 0.4, 0.8 and 1.6 gm/kg (P.O.) were evaluated. The results consistently demonstrated that only the highest dose significantly produced marked decreases in consumption of flavored solution associated with its ingestion, suppressed keypress response maintained under a 20-response fixed-ratio schedule of water presentation, and inhibited SMA. By inference, if CTA, operant behavior and SMA are appropriate paradigms, P2S, on an acute single oral high dose level, would cause GI disturbances, impair task performance and induce sedation in man.

Estimate to mutation rates

The mathematical methods for estimating the mutation rates of microbes at the level of populations are given in this paper, which are concerned with the estimation of the mixture of two normal distributions. Using the feed forward of livingthing's prior information, the precision of the estimates may be increased and the calculation may be reduced. Finally, an approximate method about the small sample is given in this paper.

Quantitative structure-activity relationships and possible mechanisms of action of bispyridinium oximes as antidotes against pinacolyl methylphosphonofluoridate

The antidotal efficacy of bispyridinium oximes against the poisoning by pinacolyl methylphosphonofluoridate can be correlated well with their physicochemical parameters. Good correlation was observed between the efficacy of antagonism against pinacolyl methylphosphonofluoridate and antinicotinic action of these oximes. X-ray structural analysis showed that these oximes possessed structural similarity to nicotine and acetylcholine of nicotinic conformation. A new model of antidotal action, other than reactivation, against the poisoning by pinacolyl methylphosphonofluoridate was proposed for these bispyridinium oximes through nicotinic receptor binding. The antagonistic efficacy of these antidotes against pinacolyl methylphosphonofluoridate may be attributed to their direct antagonism at nicotinic receptor as well as reactivation of inhibited acetylcholinesterase.

Mechanism of the reaction of thrombin with fibrin in a bovine system

The application of the Freundlich equation suggested by Seegers et al. for the description of thrombin (EC 3.4.21.5) adsorption by fibrin is inadequate in the (i) an exception has to be assumed for the interpretation of the thrombin adsorption by fibrin at higher concentrations of thrombin, and (ii) no comprehensive reaction mechanism between thrombin and fibrin is further indicated by this suggestion. Existing data are shown to suggest an interpretation which (i) may provide an explanation for the existing data without irregularity and (ii) may have implications for the mechanism of thrombin equilibrium-binding to fibrin.

Potentiation of the function of Hageman factor fragments by high molecular weight kininogen

Patients lacking high molecular weight (HMW) kininogen have profound abnormalities of the Hageman factor-dependent pathways of coagulation, kinin formation, and fibrinolysis. The ability of HMW kininogen to potentiate the Hageman factor fragments (HFf) activation of prekallikrein and Factor XI in plasma was studied. HFf only partially converted Factor XI to XIa and prekallikrein to kallikrein in plasma deficient in HMW kininogen (Williams trait), while enhanced activation of Factor XI and prekallikrein by HFf resulted after reconstitution with HMW kininogen. In a system using highly purified components, HMW kininogen increased the initial rate of prekallikrein activation whether the kallikrein formed was assayed by arginine esterase activity or kininforming ability. The potentiation of prekallikrein activation occurred over a 12-fold range of enzyme (HFf) concentration and was nonhyperbolic with respect to substrate (prekallikrein). HMW kininogen exerted its effect even in the absence of prekallikrein since the hydrolysis of acetylglycyl-lysine methyl ester by HFf was increased by HMW kininogen. These results suggest that one of the functions of HMW kininogen is to augment the catalytic action of HFf.