Comparative efficacy of gemifloxacin in experimental models of pyelonephritis and wound infection

Gemifloxacin (SB-265805) is a potent, novel fluoroquinolone with broad-spectrum antimicrobial activity. In this study, the efficacy of gemifloxacin was studied in experimental models of Gram-negative pyelonephritis (caused by Escherichia coli or Proteus mirabilis) and Gram-positive wound infection resulting from Streptococcus pyogenes, Staphylococcus epidermidis or Staphylococcus aureus. Gemifloxacin activity against these pathogens was compared with those of amoxycillin-clavulanate, ciprofloxacin, cefuroxime, azithromycin, trovafloxacin, grepafloxacin, levofloxacin and tosufloxacin. Oral treatment was initiated 1 h after infection and continued once or twice daily for 3 days. Around 17 h after the end of treatment, animals were killed and the infected kidneys or the skin around the wound site were excised for the enumeration of viable bacteria. In the pyelonephritis model (either microorganism), gemifloxacin reduced bacterial numbers significantly (P < 0.01) compared with no treatment. No comparator agent had a greater effect than gemifloxacin. Notably, grepafloxacin and azithromycin were significantly less effective (P < 0.01) than gemifloxacin against E. coli pyelonephritis, and amoxycillin-clavulanate, azithromycin and trovafloxacin were inferior (P < 0.01) against P. mirabilis infection. In the S. pyogenes wound infection model, gemifloxacin, amoxycillin-clavulanate, cefuroxime and azithromycin reduced bacterial numbers significantly compared with controls (P < 0.01). Results for the comparator quinolones were not significantly different from untreated controls (P > 0.05). Gemifloxacin was also effective against staphylococcal infection, as were grepafloxacin and levofloxacin, while ciprofloxacin, trovafloxacin and tosufloxacin were significantly less effective against these pathogens than gemifloxacin (P < 0.01). No comparator agent had greater activity than gemifloxacin against S. pyogenes or S. aureus infections. These data demonstrate the potential benefit of gemifloxacin in the treatment of Gram-negative urinary tract infection and Gram-positive skin and soft tissue infection.

Comparative in vivo activity of gemifloxacin in a rat model of respiratory tract infection

The in vivo efficacy of the novel quinolone gemifloxacin (SB-265805) was examined in a rat respiratory tract infection (RTI) model against four strains of Streptococcus pneumoniae and two strains of Haemophilus influenzae with varying susceptibilities to standard antimicrobial agents. Animals were infected intrabronchially to produce pneumonia and therapy with oral gemifloxacin, amoxycillin-clavulanate, ciprofloxacin, cefuroxime, azithromycin, trovafloxacin, grepafloxacin or levofloxacin was started 24 h after infection. The doses administered were chosen to approximate in the rat the serum or tissue concentrations measured in humans following therapeutic dosing. Therapy continued once- or twice-daily for 3 days, and approximately 17 h after the end of therapy the lungs were excised for bacterial enumeration. Following infection with strains of S. pneumoniae, gemifloxacin produced a 3-5 log reduction in bacterial numbers compared with untreated animals. Gemifloxacin was as effective as amoxycillin- clavulanate, and was as potent or more potent than all other comparators. Notably, the quinolone agents trovafloxacin, ciprofloxacin, grepafloxacin and levofloxacin were significantly less effective (P < 0.01) than gemifloxacin: these agents reduced bacterial numbers by < or =3 log compared with untreated animals. Gemifloxacin produced a marked response against H. influenzae infection, reducing bacterial numbers significantly (P < 0.01) compared with untreated controls. Gemifloxacin was significantly more potent than cefuroxime and azithromycin. None of the other comparator agents was more potent than gemifloxacin. The excellent efficacy seen in these experimental models of RTI with S. pneumoniae and H. influenzae confirms the in vitro activity of gemifloxacin against these organisms. This indicates that gemifloxacin may be of significant benefit in the treatment of RTI.

Index finger lengthening by gradual distraction and bone grafting

We present the case of an 18-year-old woman with a shortened right index finger. The digit was stabilized and lengthened a total of 18 mm by external fixation and iliac bone grafting. A distal interphalangeal fixed flexion deformity of 60 degrees was corrected with external fixation and intermedullary wiring.

Abbreviated treatment for elderly, infirm, or noncompliant patients with limited-stage small-cell lung cancer

PURPOSE

To evaluate the efficacy of an abbreviated treatment plan consisting of two cycles of chemotherapy plus thoracic irradiation in a population of limited-stage small-cell lung cancer (LSCLC) patients who were elderly, infirm, or noncompliant with standard-duration therapy.

PATIENTS AND METHODS

Fifty-five LSCLC patients (median age, 73) were treated with one cycle of cyclophosphamide, doxorubicin, and vincristine (CAV) followed 3 weeks later by one cycle of etoposide and cisplatin (EP). Both regimens were administered at conventional full dose. Thoracic irradiation (20 to 30 Gy) was delivered concurrently with EP.

RESULTS

Complete response occurred in 28 patients (51%) and partial response in 21 (38%). The median survival time was 54 weeks; the 2-year survival rate was 28% and the actual 5-year survival rate was 18%. Three patients died of toxicity.

CONCLUSION

Elderly, infirm, or noncompliant LSCLC patients who are unable to receive standard-duration chemotherapy may have useful palliation and potential for long-term survival with abbreviated chemotherapy (two cycles) and thoracic irradiation.

Refractive-Index Measurements of Undoped Yttrium Aluminum Garnet from 0.4 to 5.0 mum

We report measurements of the refractive index of undoped yttrium aluminum garnet from 0.4 to 5.0 mum and the calculation of Sellmeier coefficients based on our data. The data differ considerably from previously published reports. The effect of the new data on the design of optical devices such as intracavity etalons for lasers is discussed.

Domain motions in actin

Previous crystallographic investigations have shown that actin can undergo large conformational changes, even when complexed to the same actin binding protein. We have conducted a formal analysis of domain motions in actin, using the four available crystal structures, to classify the mechanism as either hinge or shear and to quantify the magnitude of these changes. We demonstrate that actin consists of two rigid cores, a semi-rigid domain and three conformationally variable extended loops. Confirming predictions about the nature of the domain rotation in actin based on its structural similarity to hexokinase, we show, using an algorithm previously used only to identify protein hinges, that residues at the interface between the two rigid cores undergo a shear between alternative conformations of actin. Rotations of less than 7 degrees in the torsion angles of five residues in the polypeptides that connect the rigid cores enable one actin conformation to be transformed into another. Because these torsion angle changes are small, the interface between the domains is maintained. In addition, we show that actin secondary structure elements, including those outside the rigid cores, are conformationally invariant among the four crystal structures, even when actin is complexed to different actin binding proteins. Finally, we demonstrate that the current F-actin models are inconsistent with the principles of actin conformational change identified here.

New combination of the old drugs for elderly patients with small-cell lung cancer: a phase II study of the PAVE regimen

PURPOSE

A regimen of cisplatin, doxorubicin, vincristine, and etoposide (PAVE) was designed for patients with small-cell lung cancer (SCLC) who were older than 65 years, with the following objectives compared with standard chemotherapy regimens: maintain efficacy, diminish toxicity, enhance compliance, and improve chemotherapy administration convenience at an acceptable cost.

PATIENTS AND METHODS

The PAVE regimen consisted of cisplatin 30 mg/m2 intravenously (i.v.) day 1; doxorubicin 40 mg/m2 i.v. day 1; vincristine 1.0 mg/m2 i.v. day 1; and etoposide 100 mg/m2 i.v. day 1 and orally days 3 and 5. Cycles were repeated every 3 weeks for four cycles. Patients with limited-stage disease and selected patients with extensive-stage disease received thoracic irradiation delivered concurrently with etoposide-cisplatin (EP) at the time of the second chemotherapy cycle.

RESULTS

Sixty-six eligible patients were treated, which included 25 patients with limited-stage disease and 41 patients with extensive-stage disease. Median survival was 70 weeks and 5-year survival was 25% for limited-stage disease. Median survival was 46 weeks for extensive-stage disease. Only one treatment-related death occurred and severe toxicity was infrequent. The median delivered dose-intensity was according to protocol and the mean delivered total dose was 80% of intended.

CONCLUSION

The treatment outcome achieved with PAVE in a phase II study of elderly patients compared favorably with published results of standard regimens in patient populations with better prognostic factors. Because the PAVE regimen can be delivered with good compliance, has acceptable toxicity, and is associated with logistic advantages compared with standard regimens, this protocol is suitable for further investigative trials in elderly patients with SCLC.

Effects of intravenous methylprednisolone on outcome in MRI-based prognostic subgroups in acute optic neuritis

Treatment of acute optic neuritis with steroids has been shown to hasten visual recovery without affecting the final degree of recovery. However, MRI-clinical studies indicate that patients with long optic nerve lesions, particularly those that involve the nerve within the optic canal, may have a worse prognosis for recovery of vision. Partly because such lesions could lead to swelling and subsequent ischemic optic nerve damage, steroids could have a selective beneficial effect on this subgroup of patients. The present randomized trial was designed to test this possibility. Sixty-six patients with acute optic neuritis received IV saline or IV methylprednisolone. The clinical, psychophysical, electrophysiologic, and MRI outcomes were assessed after 6 months. Patients with short lesions presented earlier than those with long lesions (involving three or more 5-mm-thick slices of any part of the optic nerve, as well as its intracanalicular portion), and lesion length was significantly less in patients presenting within a week of onset of symptoms. Lesions also tended to lengthen during follow-up in individual patients. Treatment did not limit lesion length in either the long or short lesion subgroup and had no significant effect on final visual outcome. We conclude that steroids do not improve visual outcome or lesion length in patients with acute optic neuritis.

The laryngeal mask airway reduces blood flow in the common carotid artery bulb

PURPOSE

The introduction of the laryngeal mask airway (LMA) has had a major impact on anaesthetic practice in the last ten years. Previous authors have demonstrated pressures equivalent to mean arterial blood pressure within the cuff of the LMA. This study examined the effects of cuff inflation on the cross sectional area, flow and velocity of blood flow at the level of the carotid sinus.

METHODS

Seventeen patients scheduled to have LMAs inserted as part of routine anaesthetic management were recruited into the study. Measurements of the common carotid artery bulb area, peak velocity and blood flow were performed upon LMA cuff inflation and deflation using a 5 MHz pulse wave Doppler probe.

RESULTS

Deflation of the cuff resulted in an increase in the cross sectional area (from 0.58 +/- 0.05 to 0.64 +/- 0.04 cm2; P < 0.005), an increase in blood flow (from 65.6 +/- 5.6 to 73.9 +/- 5.6 cm3.sec-1; P < 0.05) and a slight but non significant increase in velocity of blood flow.

CONCLUSION

This study demonstrates that inflation of the cuff on the LMA results in a decrease in carotid bulb cross sectional area which results in a decrease in blood flow.

Haemodynamic changes with the laryngeal mask airway--off the cuff

The cross-sectional area of the common carotid artery bulb was measured using a 5 MHz pulse wave Doppler probe in a patient undergoing general anaesthesia using a laryngeal mask airway (LMA). A simultaneous measurement of blood velocity was performed to allow determination of the blood flow. Following inflation of the cuff on the LMA, the cross-sectional area of the right carotid artery bulb decreased from 1.09 to 0.89 cm2, flow velocity increased 120 to 176 cm s-1 and the blood flow increased from 130.8 to 156.6 cm3 s-1. On the left the cross-sectional area decreased from 1.16 to 1.13 cm2, the velocity increased 136 to 151 cm s-1 and the blood flow increased from 157.8 to 170.6 cm3 s-1. While a reduction in cross-sectional area was observed in the carotid bulb in this patient, this was accompanied by an increase in the velocity and a consequent increase in blood flow. In patients with atheromatous disease involving the carotid arteries this decrease in cross-sectional area may prove clinically significant. The use of the LMA may not be suitable for this population.

Isolation of diabetes-associated kidney genes using differential display

Differential Display was used to isolate genes that show transcriptional changes in the kidney during the development of diabetes in the GK rat. Eight candidate diabetes-associated cDNA fragments, CDK1-8, were isolated and characterised. cDNA sequencing and subsequent database analysis revealed that CDK2, 4, 5 and 6 showed no significant sequence similarity to previously reported genes, suggesting that they represent novel genes, whereas CDK 1, 3, 7 and 8 showed significant similarity with rat lactate dehydrogenase, rat amiloride sensitive sodium channel, EST109013 and mouse ubiquitin-like protein respectively. The differential mRNA expression of CDK1-8 was confirmed using differential screening of slot blots. CDK1, 2, 4 and 8 mRNAs appeared to increase whereas CDK3, 5, 6 and 7 mRNAs decreased in the kidneys of GK rats with increasing hyperglycaemia. The altered renal mRNA expression of these genes in association with increased hyperglycemia in the GK rat suggest that they are candidates for a role in the development of diabetic nephropathy.

Ventricular perforation associated with central venous introducer-dilator systems

PURPOSE

Cardiac perforation is a recognised complication of guidewire-introducer techniques. These two new cases of right ventricular perforation implicate the dilator-introducer: one directly and the other due to presumed guidewire buckling.

CLINICAL FEATURES

An 85-yr-old man underwent right subclavian cannulation for triple-lumen and pulmonary artery (PA) catheter insertion before coronary artery surgery. Tachycardia (120 bpm) and hypotension (60/30 mmHg) evolved over the next 40 min and resolved with evacuation of 200 ml of clot from the pericardial sac. A ragged 4 mm laceration of the ventricular wall was localised and oversewn without further consequence. A 60-yr-old man with inferior vena caval thrombosis was scheduled for Greenfield filter insertion. The right internal jugular vein was cannulated using the guidewire-introducer technique. Introduction of the introducer-dilator system precipitated cardiovascular collapse. Resuscitation was unsuccessful and post-mortem revealed right ventricular perforation and pericardial tamponade.

CONCLUSION

These cases suggest that shorter introducer-dilators would be safer and probably equally efficacious. The need for a high index of suspicion and rapid therapeutic intervention is also highlighted.

Spinal cord atrophy and disability in multiple sclerosis. A new reproducible and sensitive MRI method with potential to monitor disease progression

Recent MRI studies in multiple sclerosis have highlighted the potential importance of spinal cord atrophy (implicating axonal loss) in the development of disability. However, the techniques applied in these initial studies have poor reproducibility which limits their application in the serial monitoring of patients. The aim of this study was to develop a highly reproducible and accurate method for the quantification of atrophy. The technique we describe demonstrates an intra-observer coefficient of variation (scan-rescan) of only 0.8%. When applied to 60 patients with clinically definite multiple sclerosis there was a strong correlation between spinal cord area and disability measured by Kurtzke's Expanded Disability Status Scale (EDSS) (r = -0.7, P < 0.001). The correlation was graded providing evidence for a causal connection. At levels 3 and 8 of the EDSS we observed a reduction in average cord area of 12 and 35%, respectively. Given its reproducibility, the magnitude of the change detected and the strong correlation with disability, this new technique should prove to be a sensitive measure of progressive neurological deterioration and could be readily incorporated into imaging protocols aimed at monitoring therapy.

Cardiorespiratory effects of laparoscopy with and without gas insufflation

BACKGROUND

Patients who are undergoing laparoscopic procedures can present with a number of ventilatory and circulatory problems. The use of a gasless technique for performing a laparoscopy by using a mechanical lifting device may potentially avoid such problems.

OBJECTIVE

To compare the cardiorespiratory effects of laparoscopy with and without gas insufflation.

METHODS

Twelve adult pigs were randomized to undergo a laparoscopy by using either carbon dioxide insufflation or mechanical elevation. Full invasive monitoring was performed preoperatively and at 10-minute intervals throughout the operative period. Parameters that were measured included blood gas determinations, mean arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, central venous pressure, cardiac output, stroke volume, and total peripheral resistance.

RESULTS

Carbon dioxide insufflation unlike mechanical elevation led to a fall in PO2 and absorption of a significant quantity of CO2, resulting in hypercapnia, acidosis, and a consequent hyperdynamic circulation.

CONCLUSION

These findings have significant implications for the use of CO2 insufflation for laparoscopy in patients with a compromised respiratory or cardiac status.

Flunarizine enhancement of melphalan activity against drug-sensitive/resistant rhabdomyosarcoma

Flunarizine, a diphenylpiperazine calcium channel blocker, is known to increase tumor blood flow. It also interferes with calmodulin function, repair of DNA damage and drug resistance associated with P-glycoprotein. Flunarizine was tested for its ability to modulate either cyclophosphamide- or melphalan-induced growth delay for a drug-resistant rhabdomyosarcoma xenograft (TE-671 MR) and the drug-sensitive parent line (TE-671), in which P-glycoprotein is not involved in the mechanism of drug resistance. Tumour blood flow was increased by 30% after a flunarizine dose of 4 mg kg-1, but no modification in growth delay was induced by melphalan (12 mg kg-1). In contrast, a 60 mg kg-1 dose of flunarizine had no effect on tumour blood flow, but the same dose created significant enhancement in melphalan-induced tumour regrowth delay in both tumour lines. The dose-modifying factor for flunarizine as an adjuvant to melphalan was approximately 2 for both tumour lines. Although blood flow measurements were not performed with the combination of flunarizine and melphalan, the results from flunarizine alone suggested that augmentation of melphalan cytotoxicity is not mediated by changes in blood flow. In contrast, flunarizine did not affect drug sensitivity to cyclophosphamide in groups of animals bearing the drug-sensitive parent tumour line. These results suggest that the mechanism of drug sensitivity modification by flunarizine is not related to modification of tumour blood flow, but may be mediated by modification of transport mechanisms that are differentially responsible for cellular uptake and retention of melphalan as compared with cyclophosphamide.

Response of guinea pigs to a vaccine containing a new adjuvant (SAF) and gram-negative bacteria

Porphyromonas gingivalis is a gram-negative pathogen associated with severe periodontitis in man and other animals. A vaccine against P. gingivalis infection may improve resistance to such infection and disease progression in susceptible individuals. A vaccine composed of formalin-killed P. gingivalis and Syntex adjuvant formulation or saline was tested in guinea pigs. Blood was drawn before and at 2, 4, 6, 8, 24, and 27 weeks after immunization. There was no morbidity or mortality as a result of vaccination, and necropsy revealed no organ abnormalities or residual injection site granulomas. Serum immunoglobulin G (IgG) antibody titer and avidity were measured by enzyme-linked immunosorbent assay, and Western blots were done to determine the immunodominant antigens. The IgG titer increased more rapidly and reached higher values in the animals receiving SAF plus P. gingivalis vaccine than in those receiving saline plus P. gingivalis. Antibody titer decreased by 27 weeks, but avidity was twofold greater at 27 than at 8 weeks. Western blots indicated that protein and carbohydrate antigens are recognized.