Determination of the in vivo post-antibiotic effects of ciprofloxacin and rifampicin

A modified rabbit meningitis model is described for determining the PAE in vivo, which utilised a self-standing device for repeatedly sampling pure CSF. The model allowed the PAEs of ciprofloxacin and rifampicin on Escherichia coli ATCC 25922 to be determined following PAE induction in vitro, or in vivo in CSF after intrathecal injection or during the last 1.5 h of a 7 h iv continuous infusion. The estimated volumes of distribution of ciprofloxacin and rifampicin in CSF were 0.68 +/- 0.24 mL and 0.74 +/- 0.04 mL, respectively, and the terminal elimination half lives were 1.8 +/- 0.5 h and 2.2 +/- 0.3 h, respectively. PAEs of approximately 2 h were obtained in vivo and in vitro after exposing E. coli to 3 x MIC of ciprofloxacin in vitro and to 1 x MIC of drug in vivo. When the organism was exposed to rapidly declining concentrations in vivo, only a minimal PAE was observed for both antibiotics. Moreover, a PAE of 3.1 +/- 1.3 h of rifampicin was obtained in vivo, being smaller than the 4.8 h PAE observed in vitro, which might be explained by the binding of 45 +/- 6.5% rifampicin to proteins in the CSF.

Superficial carcinomas of the esophagus and gastric cardia. A clinicopathological analysis of 141 cases

From January 1970 to June 1992, 141 patients with superficial esophageal and cardiac carcinomas (SEC and SCC) underwent surgical treatment. Of the 141 patients 128(90.8%) had slight symptoms related to swallowing, and the remaining 13(9.2%) were asymptomatic. Balloon cytology and esophagoscopy proved very useful for the diagnosis of SEC and SCC, and Lugol's solution staining technique was an effective auxiliary diagnostic measure. Lymph node metastasis was not found in patients with epithelial (EP) cancer. However, it was present in one (2.9%) of 34 patients with muscularis mucosal (MM) invasion, and in 5 (8.6%) of 58 patients with submucosal (SM) cancer. The 5-year survival rates of the patients with SEC and SCC were 75.5% and 71.4%, respectively (P > 0.05). The different depth of tumor invasion including EP, MM and SM cancers showed significant differences in the 5-year survival rate (P < 0.05). Although the prognosis for the patients with lymph node metastasis is poor, we should advocate extended lymph node dissection in surgical treatment of the patients in whom MM and SM cancers are suspected.

Differentiation of murine embryonal carcinoma in vitro and in vivo with N,N-dimethyl acetamide

Polar solvents such as N,N-dimethyl acetamide (DMA) are known inducers of tumor cell differentiation in vitro. Nothing is known about their ability to induce differentiation in vivo. Using PCC4 AZArL murine embryonal carcinoma (EC) cells we examined the time course and dose response relationship of DMA induced EC differentiation in vitro. The effective continuous dose range of 0.1% to 0.15% gave a linear increase in differentiation index with the probability of attaining complete differentiation. EC tumors were raised subcutaneously in the flanks of strain 129 mice and DMA injected intraperitoneally at a dose calculated to attain tissue levels of between 0.1% and 0.15%. DMA induced significant differentiation primarily into neuroepithelium when compared to negative controls, but DMA was not as effective as retinoic acid. The extent of differentiation was dosage dependent, but the maximal dose of DMA was limited by toxicity mainly to the liver and lymphoid tissues. A graduated dosage schedule of DMA treatment reduced toxicity. These preliminary studies suggest that "differentiation therapy" with polar solvents such as DMA may be an effective adjunct to standard therapies.

Potential gene therapy strategies in the treatment of cardiovascular disease

Gene therapy is the introduction of new genetic material into somatic cells to synthesize missing or defective proteins. Efficient methods for the introduction of genetic material into cells are available, both in vitro and in vivo. These strategies involve chemical, physical, and viral-mediated mechanisms of gene transfer. Application of these gene transfer techniques has led to the development of potential gene-based treatment strategies that could combat vascular and myocardial disease. Gene therapy in the treatment of cardiovascular disease promises to alter atherosclerotic risk factors, prevent vascular thrombotic disease, retard progression of disease in the peripheral vasculature, provide drug delivery systems, and prevent myocardial infarction in patients with coronary artery disease. This exciting technology will eventually become the ultimate intervention in the treatment of cardiovascular disease.

Mechanisms of immature myocardial tolerance to ischemia: phenotypic differences in antioxidants, stress proteins, and oxidases

BACKGROUND

Previous work has suggested tolerance to ischemic injury in newborn myocardium. Although various mechanisms for this protection have been proposed, a link between oxidant-antioxidant factors, stress protein expression, and protection from cardiac ischemia/reperfusion (I/R) injury has not been made in newborn myocardium. We hypothesized total newborn myocardial resistance to I/R is related to decreased oxygen radical producing potential, increased free radical scavenging capacity and augmented stress protein expression. The purposes of the study were to examine in newborn and adult rat hearts (1) functional recovery from I/R, (2) catalase and xanthine oxidase (XO) activities, and (3) heat shock protein 72 (HSP 72) expression.

METHODS

Isolated rat hearts (7 to 10 days versus 60 days) were perfused on a nonworking Langendorff apparatus at 60 mm Hg (Krebs-Henseleit buffer, pH 7.4, 37 degrees C) and subjected to 20 minutes of global ischemia and 40 minutes of reperfusion. Left ventricular developed pressure was recorded by using a left ventricular catheter. Catalase and XO were measured by means of standard assays, and HSP 72 was assessed with in situ immunohistochemistry.

RESULTS

Newborn rat hearts had greater percentage functional recovery of left ventricular developed pressure after I/R (66.0% +/- 4.2% versus 44.3% +/- 3.5%; p < 0.05). The newborn myocardium also had increased catalase activity (1027.9 +/- 20.6 units/gm versus 707.3 +/- 38.7 units/gm; p < 0.05), whereas the activity of XO was decreased relative to the adult (0.23 +/- 0.01 mU/gm versus 7.6 +/- 1.4 mU/gm; p < 0.05). Furthermore, the expression of HSP 72 was greater in the newborn than the adult control.

CONCLUSIONS

Relative to adult hearts, newborn rat hearts are more tolerant to a global ischemic insult followed by reperfusion. This improved functional recovery is associated with decreased oxidant production potential (XO), increased scavenging capacity (catalase), and augmented stress protein expression (HSP 72).

[Diagnosis and treatment of interrupted aortic arch: report of 6 cases]

Six patients with interrupted aortic arch were operated on from Nov. 1986 to Jun. 1992. 4 patients were type A and 2 type B. The result was good except a patients of type A died early after operation. Two-stage operation was performed for 4 patients of type A, and 2 patients of type B accepted posterolateral incision. The aortic arch was constructed with artificial vessel. Cardiopulmonary bypass was set up with patients lying on back, then PDA was ligated and VSD closed. Pulmonary artery trunk reconstruction and VSD closing were performed. Three months after operation a patient died of septicemia caused by infection of incision.

Dysfunction of cGMP-mediated pulmonary vasorelaxation in endotoxin-induced acute lung injury

Endothelial-dependent and -independent cGMP-mediated mechanisms of pulmonary vasorelaxation were studied in endotoxin-induced acute lung injury in the rat. Concentration-response curves were generated (10(-9) to 10(-6) M) for acetylcholine (ACh), A23187, and sodium nitroprusside (SNP) and for 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) (10(-9) to 10(-4) M) in isolated pulmonary arterial rings preconstricted with phenylephrine 6 h after endotoxin treatment (20 mg/kg ip). Endotoxin treatment produced significantly increased lung neutrophil accumulation (myeloperoxidase assay, 28 +/- 6 units/g lung tissue vs. 1.8 +/- 1 in controls) and lung leakage (lung/blood 125I-labeled albumin ratio, 0.06 +/- 0.01 vs. 0.028 +/- 0.01 in controls) as well as histological evidence of pulmonary vascular endothelial damage. The concentration-response curves demonstrated that pulmonary vasorelaxation by mechanisms that require generation of cGMP by either endothelial-dependent (both receptor-dependent, ACh, and receptor-independent, A23187) or endothelial-independent (SNP) pathways were significantly impaired after endotoxin treatment. Relaxation by stimulation with the cGMP analogue 8-BrcGMP was not different from control. Pulmonary vascular smooth muscle is able to relax in response to cGMP after endotoxin treatment, but relaxation by endothelial-dependent and -independent pathways that require generation of cGMP is significantly impaired.

Optical mapping of lambda bacteriophage clones using restriction endonucleases

Optical mapping is an emerging single molecule approach for the rapid generation of ordered restriction maps, using fluorescence microscopy. We have improved the size resolution of optical mapping by imaging individual DNA molecules elongated and fixed onto derivatized glass surfaces. Averaged fluorescence intensity and apparent length measurements accurately determined the mass of restriction fragments 800 basepairs long. We have used optical mapping to create ordered restriction maps for lambda clones derived from the mouse pygmy locus.

[Identification of chaihu guizhi ganjiang decoction by three dimensional HPLC]

The Chaihu Guizhi Ganjiang Decoction was identified by three dimensional HPLC. The result showed that the constituents in this decoction, namely Radix Bupleuri; Ramulus Cinnamomi; Radix Glycyrrhizae and Radix Scutellariae could all be identified clearly.

[Effects of Sichuan herba Epimedii on the concentration of plasma middle molecular substances and sulfhydryl group of "yang-deficiency" model animal]

The effects of tonifying the kidney and strengthening the "Yang" produced by the extracts of Chinese herbs Epimedium wushanense and E. pubescens were studied in this paper. The results showed that both two herbs could decrease the concentration of plasma middle molecular substances and increase the concentration of plasma sulfhydryl group of "Yang-deficiency" model mice, thus suggesting that the above-said tonifying and strengthening effects of Herba Epimedii may result from its effects on middle molecular substances and sulfhydryl group, so as to strengthen the body resistance and eliminate the invading pathogenic factors.

Intravenous ascorbate as a tumor cytotoxic chemotherapeutic agent

Ascorbic acid and its salts (AA) are preferentially toxic to tumor cells in vitro and in vivo. Given in high enough doses to maintain plasma concentrations above levels that have been shown to be toxic to tumor cells in vitro, AA has the potential to selectively kill tumor cells in a manner similar to other tumor cytotoxic chemotherapeutic agents. Most studies of AA and cancer to date have not utilized high enough doses of AA to maintain tumor cytotoxic plasma concentrations of AA. Data are presented which demonstrate the ability to sustain plasma levels of AA in humans above levels which are toxic to tumor cells in vitro and suggests the feasibility of using AA as a cytotoxic chemotherapeutic agent.

Isolation of chicken hsp90 beta gene promoter

In order to define the mechanisms responsible for the differential expression of chicken hsp90 alpha and beta genes, a portion of the chicken hsp90 beta genomic sequence, including 3081 bp upstream from the transcription initiation site and 2718 bp of structural gene sequence which covers 7 exons and 6 introns was investigated. The transcriptional initiation site was determined by primer extension, RNAase and S1 nuclease mapping, Northern blot and cloning of 5' end of cDNA. The first intron, as in other hsp90 genes, is located just before the ATG initiation codon. Three Sp1 sites are located near the TATA box. The apparent major divergence with the hsp90 alpha promoter is that, in the hsp90 beta promoter, the only CAAT box and HSE element are located at about 3 and 2 kb upstream the TATA box, respectively. These features may explain why chicken hsp90 beta mRNA is generally less abundant than alpha and is not inducible by heat shock or serum/growth factor stimulation.

Preconditioning of isolated rat heart is mediated by protein kinase C

Catecholamines have been implicated in the phenomenon of ischemic preconditioning. We have previously demonstrated that ischemic preconditioning against postischemic mechanical dysfunction in the isolated rat heart is mediated by the alpha 1-adrenergic receptor. The purpose of this study was to delineate the signal transduction of preconditioning distal to the alpha 1-adrenergic receptor. Our results suggest that (1) transient ischemia and alpha 1-adrenergic receptor-induced preconditioning is inhibited by protein kinase C (PKC) antagonists, (2) functional protection against global ischemia/reperfusion injury can be induced by infusion of diacylglycerol, the second messenger of the alpha 1-adrenergic pathway, and (3) transient ischemia and alpha 1-adrenergic preconditioning are both characterized by similar translocation of PKC-delta to the sarcolemma of myocardium. These findings suggest that PKC is an effector of preconditioning in the isolated rat heart.

Clinical assessment of biplanar transesophageal echocardiography--a report of 125 cases

One hundred and twenty-five patients with cardiovascular disease were examined by biplanar transesophageal echocardiography (BTEE), including 67 with rheumatic heart disease (7 monitored during operation), 22 with aortic diseases, 20 with congenital heart diseases, and 16 with other kinds of heart disease. The results showed that BTEE was not influenced by corpulent and pulmonary emphysema and was better than transthoracic echocardiography at imaging the interatrial septum, left atrium and left atrial appendage, thoracic aorta, and mitral artificial valve and at intraoperative monitoring. BTEE was also better than single-plane transesophageal echocardiography, because BTEE could be used to observe the heart and thoracic aorta in transverse and longitudinal planes, thus enlarging the transmission "window" as well as allowing the entire lesion to be imaged. This study suggests that BTEE will have good prospects in clinical application.

Optimal batch size for estimation of the prevalence of a disease using combined samples

Great attention has been given to the combined sample test for its high efficiency. Here a model of mathematical expectation for combined samples has been worked out and used for investigating the prevalence of HCV in serum from blood donors. It was shown that this model was valuable if the probability of a positive test, e.g. the prevalence, is less than 0.31.

Redox mechanism for the chaperone activity of heat shock proteins HSPs 60, 70 and 90 as suggested by hydrophobic cluster analysis: hypothesis

We have recently shown that the N-terminal ATPase fragment of hsp70 (1-375, composed of domains I and II) as well as the subsequent domain III (376-520) may share three-dimensional similarities with hsp60. In this study, we propose that domain III, common to the hsp60s and hsp70s is also found in the hsp90s and adopts a beta-alpha-beta Rossmann-folded structure which is encountered in the NAD-binding domain of dehydrogenases. Consequently, with the help of the domain IV (in hsp70s and hsp90s) or of hsp10/GroES (in hsp60s) and possibly that of auxilliary partners, the hsp molecules could act as "unfoldases" or "reset systems" by disrupting secondary structures through redox reactions on the main polypeptidic chain with which they interact. The models built on this hypothesis may open up a new way for understanding the chaperone functions within the folding/unfolding processes.

Mechanisms of coronary vasomotor dysfunction in the transplanted heart

The transplanted heart sustains both cold ischemic and reperfusion injuries. These can produce coronary vascular endothelial or smooth muscle injury or both, which, in turn, can produce coronary vasomotor dysfunction. Using a canine model of autologous heart transplantation, we examined the following coronary vasomotor control mechanisms in isolated coronary artery rings: (1) endothelial-dependent cyclic guanosine monophosphate (cGMP)-mediated vasorelaxation (response to acetylcholine); (2) endothelial-independent cGMP-mediated vasorelaxation (response to sodium nitroprusside); and (3) beta-adrenergic cyclic adenosine monophosphate (cAMP)-mediated vasorelaxation (response to isoproterenol hydrochloride). Further, these mechanisms were related to 3 hours of cold ischemia alone and to 3 hours of cold ischemia plus 1 hour of reperfusion. Autologous heart transplantation was performed in dogs, and isolated distal left anterior descending coronary artery rings were studied in individual organ chambers. Cold ischemia alone produced significant dysfunction of beta-adrenergic cAMP-mediated vasorelaxation, which was exacerbated after reperfusion. Neither endothelial-dependent nor endothelial-independent cGMP-mediated vasorelaxation was dysfunctional after cold ischemia alone, but both were significantly impaired after reperfusion. We conclude that cold ischemia and reperfusion each produce coronary vasomotor dysfunction in the transplanted heart. Cumulatively, such coronary vasomotor dysfunction can acutely impair coronary vasodilatation and potentially jeopardize myocardial blood flow in the transplanted heart.

Improved microplate fluorometer counting of viable tumor and normal cells

An improved method has been developed to count cells in situ based on the measurement of esterase activity with carboxyfluorescein diacetate. This sensitive, semiautomated microplate fluorometer assay was able to estimate viable cell numbers over a range of 5 x 10(2) to 2.6 x 10(5) cells/well in a tumor cell line. Sensitivity to 10(3) was demonstrated in two other cell lines. Sub- and supranormal fluorescence events which can be responsible for unreliable readings when using a fluorescence assay for cell counting were quantified in a menadione (cytotoxic agent)/U-87 MG (cell line) model. There was a close correlation between the fluorometer method and Coulter counter method for two different tumor cell lines when this method was performed on cells after sub- and supranormal fluorescence events had ceased.

An improved HPLC assay for ciprofloxacin in biological samples

A simple and sensitive high performance liquid chromatographic method was developed for determination of ciprofloxacin (Cip) in 0.1 ml of rabbit and human serum and CSF. Separation of Cip and pipemidic acid (internal standard) was achieved on Nucleosil C18 (4.6 mm x 250 mm) using fluorescence detection with lambda exc 274 nm and lambda emi 418 nm. The mobile phase was composed of acetonitrile and phosphate buffer 10 mmol.L-1 (pH 2.7) containing tetrabutylammonium hydrogen sulfate 5 mmol.L-1 (18:82, vol:vol) and the flow rate was set at 1.0 ml.min-1. The retention times were 5.9 min for Cip and 4.0 min for pipemidic acid. The inter-day coefficient of variation was < 6.97% (n = 5) and the intra-day coefficient of variation was < 3.33% (n = 5). The limits of detection were 3 ng.ml-1 serum and 5 ng.ml-1 CSF, (r > or = 0.9996). Application of this method was demonstrated with simultaneous measurements of concentration-time profiles of Cip in rabbit serum and CSF during iv infusions at constant rates of 0.33, 1.0, and 2.5 mg.kg-1.h-1.

[The preliminary experiences of diagnosis and treatment for hypercalcemia crisis--clinical analysis of 23 cases]

This article report a study of 23 cases of hypercalcemia crisis resulting from primary hyperparathyroidism (18 cases), carcinoma (4 cases) and vitamin D intoxication (1 case). In addition to the symptoms of primary diseases, the patients with hypercalcemia crisis often had anorexia, nausea, vomiting, polydipsia, polyuria, psychoneurotic symptoms, arrhthmia. The severity of the symptoms was proportional to the degree of hypercalcimia. Serum calcium concentration of patients in hypercalcemia crisis should be equal or higher than 3.75 mmol/L (15 mg/dl) or serum ionized calcium higher than 1.88 mmol/L. Treatment hypercalcemia crisis consisted of rapidly lowering the serum calcium level by various measures while actively treating the primary diseases. Our experience is to supply normal saline intravenously or orally to increase the extracellular fluid and to enhance excretion of the urine calcium by administrating furosemide. In this paper, serum calcium concentration of 5 patients with hypercalcemia crisis treated with salmen calcitonin was reduced in varying degrees. The above mentioned treatment would be beneficial to the alleviation of the crisis and the preparation for operative treatment.

Loss of bactericidal activities of quinolones during the post-antibiotic effect induced by rifampicin

The post-antibiotic effect (PAE) is the phenomenon of persisting suppression of bacterial growth as a result of prior antimicrobial exposure. In antimicrobial therapy, multiple doses of either a single drug or a combination of drugs are common. Accordingly, the following question may arise: what impact might the PAE induced by the previous dose impose on the subsequent bactericidal action of a cycle-specific antibiotic. To answer the question, a study was conducted using pefloxacin, norfloxacin, ciprofloxacin and ofloxacin as test drugs, rifampicin as the PAE inducer and Escherichia coli ATCC 25922 as the test organism. Bacterial kill kinetics were determined for each quinolone at 4 x MIC before rifampicin treatment and during the PAE period following rifampicin challenge. The relative bactericidal activity of the quinolones during the PAE period was calculated. During the PAE period, pefloxacin, norfloxacin, ciprofloxacin and ofloxacin displayed only 6%, 8%, 7% and 33% of their normal activities, respectively. The results were compared to those obtained at low temperature (4 degrees C) and when the cells were challenged simultaneously with a quinolone and with rifampicin. The findings of this study suggest that prolonging the dosing interval by taking the PAE into account may not only lower the cost of antimicrobial therapy and the risk of toxicity, but also ensure the efficacy of subsequent doses.

[The diagnosis of primary hyperparathyroidism--analysis of 134 cases]

This article reports the diagnostic experiences of 134 cases of primary hyperparathyroidism (PHPT) confirmed by operation and pathologic examination. The clinical presentations were divided into 4 types: (1) 75 cases (56.0%) with bone resorption; (2) 47 cases (35.0%) with bone lesions plus urinary calculus; (3) 8 cases (6.0%) with urinary calculus only and; (4) 4 cases (3.0%) with hypercalcemia only. Bone lesions included bone resorption, osteomalacia and osteoporosis. Stones at multiple sites in the urinary tract or nephrocalcinosis were found in 41 cases. The measurement of ionized calcium was much more sensitive and accurate than the total calcium assay with the positive rate of 95.3% and 73.4% respectively. The concentration of plasma iPTH was high in the whole group (n = 84), the mean value was 21.4 +/- 17.9 times higher than that of the normal control group. For the localization of the affected parathyroid gland, instiat examination was by neck ultrasonography which gone a positive predictive value of 81.5% (43/53), 99mTc-MIBI scan showed positive rate 94.1% (16/17). The CT scan of the chest was used when ectopic location in mediastinum was highly suspected. If the first operative exploration failed to find the affected parathyroid gland, we performed the determinations of iPTH with samples taken from internal jugular vein through selective venous catheterization; the coincidence rate was found to be 85.2% (23/27).

[Experimental study on intratumoral injection with hydroxyapatite bioceramics and adriamycin in implanted hepatoma in mice]

Hydroxyapatite (HA) bioceramics is a biomaterial used in orthopedic area. We observed its anticancer effect in experimental hepatoma-22 (H22) in mice. BALB/c mice implanted with H22 were grouped into I, II, III and IV. Intratumoral injections were given as follows: (I) HA 0.1 g and ADM 0.1 mg n = 28; (II) HA 0.1 g n = 16; (III) ADM 0.1 mg n = 16; (IV) untreated n = 20. The tumor regression rates of the groups I, II and III were 65.9%, 41.9% and 51.1%, respectively. The mean survivals of groups I, II, III and IV were 32, 22, 26 and 18 days. Six mice of group I were alive more than 50 days before being killed, in which 4 tumor samples showed that no residual tumor cells could be seen under microscope. The possible mechanism of HA anti-cancer action is: (1) the dissolved matter of HA, glycoprotein and microfibril around the tumor cells may disturb the metabolism of cancer; (2) fibrocalcific process restricts the tumor growth; (3) immunoenhancement action (4) as a drug-release system HA is a hopeful agent of intratumoral injection for treatment of cancer.