Enhancement of the therapeutic efficacy of the MAP regimen using thiamine pyrophosphate-decorated albumin nanoclusters in osteosarcoma treatment

Recent studies on osteosarcoma regimens have mainly focused on modifying the combination of antineoplastic agents rather than enhancing the therapeutic efficacy of each component. Here, an albumin nanocluster (NC)-assisted methotrexate (MTX), doxorubicin (DOX), and cisplatin (MAP) regimen with improved antitumor efficacy is presented. Human serum albumin (HSA) is decorated with thiamine pyrophosphate (TPP) to increase the affinity to the bone tumor microenvironment (TME). MTX or DOX (hydrophobic MAP components) is adsorbed to HSA-TPP via hydrophobic interactions. MTX- or DOX-adsorbed HSA-TPP NCs exhibit 20.8- and 1.64-fold higher binding affinity to hydroxyapatite, respectively, than corresponding HSA NCs, suggesting improved targeting ability to the bone TME via TPP decoration. A modified MAP regimen consisting of MTX- or DOX-adsorbed HSA-TPP NCs and free cisplatin displays a higher synergistic anticancer effect in HOS/MNNG human osteosarcoma cells than conventional MAP. TPP-decorated NCs show 1.53-fold higher tumor accumulation than unmodified NCs in an orthotopic osteosarcoma mouse model, indicating increased bone tumor distribution. As a result, the modified regimen more significantly suppresses tumor growth in vivo than solution-based conventional MAP, suggesting that HSA-TPP NC-assisted MAP may be a promising strategy for osteosarcoma treatment.

Emergence of Rsv-resistance breaking Soybean mosaic virus isolates from Korean soybean cultivars

Twelve Rsv resistance-breaking (RB) isolates of Soybean mosaic virus (SMV) were obtained from field-grown soybean plants showing mosaic symptoms and subsequently examined biologically and molecularly. All of these RB isolates were identified as SMV based on serological and infectivity assays, and the amplification of P1 gene products by reverse transcription-polymerase chain reaction (RT-PCR). Differential soybean cultivars, lines or accessions Lee 68 (rsv), PI 96983, York, Marshall, Ogden, Kwanggyo, Suweon 97 (Rsv1 alleles), L29 (Rsv3), and V94-5152 (Rsv4), following inoculation with each RB isolate, showed similar systemic symptoms suggesting that these RB isolates can overcome Rsv resistance at three loci. To differentiate the 12 RB isolates molecularly, the P1 coding region for each isolate was amplified, cloned, sequenced and compared to known SMV strains. The P1 region from the RB isolates shared 86-90% and 90-99% similarities in amino acid (aa) and nucleotide sequence, respectively, with known SMV strains. Comparison of aa sequences indicated that these RB isolates are newly emerging isolates capable of breaking Rsv resistance. Phylogenetic analysis further suggested that the RB isolates can be classified as three major types. However, recombination was not observed within the coding region of P1 protein among the types. This is the first report on the emergence of SMV isolates capable of overcoming all of the known resistance alleles at the Rsv1 locus, as well as distinct resistance genes at Rsv3 and Rsv4.

Airway reactivity to bronchoconstrictor and bronchodilator: assessment using thin-section and volumetric three-dimensional CT

OBJECTIVE

To determine the extent to which thin-section and volumetric threedimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity.

MATERIALS AND METHODS

In eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were measured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways.

RESULTS

Cross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pressure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size.

CONCLUSION

Thin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size.

Lobular low attenuation of the lung parenchyma on CT: evaluation of forty-eight patients

PURPOSE

Our goal was to analyze patients with pulmonary lobular low attenuation (LLA) on thin section CT with regard to the underlying pulmonary diseases and the dynamic changes occurring in the low attenuation regions during respiration.

METHOD

Forty-eight consecutive patients with LLA on thin section CT were analyzed retrospectively. Forty-six patients (95%) had symptoms related to respiratory disease, such as productive cough (n = 25) and hemoptysis (n = 18). Only two patients, one with chronic pulmonary embolism and one with Takayasu arteritis combined with bronchiectasis, had pulmonary vascular disease. Six patients, four with bronchiectasis and two with vascular disease, were studied with dynamic CT during forced vital capacity maneuver. Attenuation values for LLA areas and adjacent lung were measured and time-density curves were plotted.

RESULTS

Forty-one (85%) patients had bronchiectasis, typically in other than the regions of the LLA. Areas with proximal bronchiectasis showed low attenuation but without notable lobular distribution. Pulmonary vessels in the LLA areas were smaller than those of adjacent normal lung (n = 45). Of 22 patients who underwent pulmonary function tests, 15 had obstructive pattern of impairment. Respiratory dynamic CT showed expiratory air trapping in LLA areas in all six patients. The mean attenuation values of LLA areas were lower than those of the adjacent normal lung by 67 HU at end-inspiration and by 165 HU at end-expiration (p = 0.002).

CONCLUSION

The majority of the patients with LLA shown by thin section CT had bronchiectasis elsewhere in the lung, and evidence of air trapping in the LLA was clearly demonstrated. Bronchiolar obstruction may be the most prevalent cause for the development of LLA.

Effect of standard-dose trimethoprim/sulfamethoxazole on the serum potassium concentration in elderly men

OBJECTIVE

To determine the effect of standard-dose trimethoprim/sulfamethoxazole (TMP/SMX) (TMP 160 mg and SMX 800 mg q12h) on the serum potassium concentration.

DESIGN

Retrospective and concurrent study.

SETTING

A Veterans Affairs Medical Center.

PATIENTS

Fifty-three men hospitalized at the Fargo Veterans Affairs Medical Center. Thirty-three patients who received standard-dose TMP/SMX for 3 or more days comprised the study group. Twenty patients who received oral cephradine or amoxicillin for 3 or more days comprised the control group. Patients who received potassium supplements, potassium-sparing diuretics, angiotensin-converting enzyme inhibitors, nonsteroidal antiinflammatory drugs, beta-blockers, heparin, known nephrotoxic agents, patients with a serum creatinine concentration of more than 177 mumol/L, and patients with baseline hyperkalemia (serum potassium concentration > 5.1 mmol/L) were excluded.

RESULTS

The serum potassium concentration in the study group was 4.22 +/- 0.40 mmol/L and increased by 0.31 +/- 0.38 mmol/L at the end of therapy (p < 0.001). Twenty-six patients in the study group (78.8%) had an increase in the serum potassium concentration during TMP/SMX therapy. Fourteen of these patients had follow-up serum potassium concentrations obtained after completion of therapy. The serum potassium concentration returned to baseline in 10 of these patients. The serum creatinine concentration also increased during therapy. However, the correlation between the increase in the serum potassium concentration and the increase in the serum creatinine concentration was weak (Pearson r = 0.29). The serum potassium in the control group was 4.34 mmol/L and remained essentially unchanged during therapy.

CONCLUSIONS

Therapy with standard-dose TMP/SMX is associated with a slight increase in the serum potassium concentration. Routine monitoring of the serum potassium concentration in patients who are treated with standard-dose TMP/SMX therapy is unnecessary. However, TMP/SMX should be considered as a possible cause of unexplained hyperkalemia in elderly patients receiving TMP/SMX therapy.

Cost of inappropriate use of ciprofloxacin in ambulatory care

OBJECTIVE

To determine the incidence of inappropriate ciprofloxacin use and the resulting cost thereof in ambulatory care.

DESIGN

Retrospective cost analysis.

SETTING

Ambulatory care clinic of a Department of Veterans Affairs Medical Center.

PATIENTS

One hundred thirty-seven ambulatory patients prescribed ciprofloxacin during March, April, and May 1992. Forty-six patient charts were available for review.

MAIN OUTCOME MEASURE

Indications for ciprofloxacin use were determined from chart review.

RESULTS

Chart review of 46 of the 137 patients prescribed ciprofloxacin during the three-month study period indicated that only 8 (17 percent) had infections that were appropriately treated with this antibiotic. If 550 patients had received ciprofloxacin that year (figure extrapolated from the three-month totals), the cost of prescribing would have been $29,260. This study indicates that $20,500 per year could be saved by prescribing equally efficacious oral antibiotics.

CONCLUSIONS

Restricting ciprofloxacin use to its proven indications in the ambulatory setting may result in considerable cost savings to medical centers.