Treatment regimens including the multitargeted antifolate LY231514 in human tumor xenografts

The scheduling of antifolate antitumor agents, including the new multitargeted autofolate LY231514 (MTA), with 5-fluorouracil was explored in the human MX-1 breast carcinoma and human H460 and Calu-6 non-small cell lung carcinoma xenografts to assess antitumor activity and toxicity (body weight loss). Administration of the antifolate (methotrexate, MTA, or LY309887) 6 h prior to administration of 5-fluorouracil resulted in additive growth delay of the MX-1 tumor when the antifolate was methotrexate or LY309887 and greater-than-additive tumor growth delay (TGD) when the antifolate was MTA. In the H460 tumor, the most effective regimens were a 14-day course of MTA or LY309887 along with 5-fluorouracil administered on the final 5 days. In addition, the simultaneous combination of MTA administered daily for 5 days for 2 weeks with administration of gemcitabine resulted in greater-than-additive H460 TGD. MTA was additive with fractionated radiation therapy in the H460 tumor when the drug was administered prior to each radiation fraction. MTA administered along with paclitaxel produced greater-than-additive H460 TGD and additive responses along with vinorelbine and carboplatin. In the Calu-6 non-small cell lung carcinoma xenograft, MTA administered in combination with cisplatin or oxaliplatin was highly effective, whereas MTA administered in combination with cyclophosphamide, gemcitabine, or doxorubicin produced additive responses. Administration of MTA along with paclitaxel or doxorubicin resulted in additive MX-1 TGD. Thus, MTA appears to be especially effective in combination therapies including 5-fluorouracil or an antitumor platinum complex.

Pulmonary disorders: ventilation-perfusion MR imaging with animal models

PURPOSE

To demonstrate the capability of magnetic resonance (MR) imaging to assess alteration in regional pulmonary ventilation and perfusion with animal models of airway obstruction and pulmonary embolism.

MATERIALS AND METHODS

Airway obstruction was created by inflating a 5-F balloon catheter into a secondary bronchus. Pulmonary emboli were created by injecting thrombi into the inferior vena cava. Regional pulmonary ventilation was assessed with 100% oxygen as a T1 contrast agent. Regional pulmonary perfusion was assessed with a two-dimensional fast low-angle shot, or FLASH, sequence with short repetition and echo times after intravenous administration of gadopentetate dimeglumine.

RESULTS

Matched ventilation and perfusion abnormalities were identified in all animals with airway obstruction. MR perfusion defects without ventilation abnormalities were seen in all animals with pulmonary emboli.

CONCLUSION

Ventilation and perfusion MR imaging are able to provide regional pulmonary functional information with high spatial and temporal resolution. The ability of MR imaging to assess both the magnitude and regional distribution of pulmonary functional impairment could have an important effect on the evaluation of lung disease.

Streptococcal meningitis: effect of CSF filtration on inflammation and neuronal damage

The effect of CSF filtration on inflammation and neuronal damage was studied in experimental Streptococcus pneumoniae meningitis. New Zealand white rabbits received either antibiotic therapy alone (ceftriaxone i.v., 20 mg/kg bolus, 10 mg/kg maintenance dose; n = 10) or ceftriaxone plus CSF filtration (n = 11) 12 h after intracisternal infection. Immediately after the onset of antibiotic therapy 300 microliters cisternal CSF was removed, passed through a miniaturized CSF-1 filter at a constant flow of 20 microliters/min, and then reinjected. This procedure was repeated six times at intervals of 20 min. Antibiosis plus CSF filtration caused a transient reduction in CSF bacterial titers and leukocyte counts compared with antibiosis alone (P = 0.04 and 0.02 5 h after initiation of therapy). CSF lipoteichoic acid concentrations were not reduced. The concentration of neuron-specific enolase in CSF and the density of apoptotic neurons in the dentate gyrus were almost equal 12 h after the onset of treatment. Adjuvant CSF filtration accelerated the elimination of viable bacteria from CSF in comparison to antibiotic treatment alone. Parameters of neuronal destruction, however, were not reduced.

Circadian rhythm of motor restlessness and sensory symptoms in the idiopathic restless legs syndrome

STUDY OBJECTIVES

To determine if motor restlessness in the Restless Legs Syndrome (RLS) shows a circadian rhythm with maximum at night, as previously found for subjective discomfort and periodic limb movements (PLMs), and to correlate RLS peak intensity with the core temperature cycle.

DESIGN

Subjects underwent two days of normally timed wakefulness and sleep followed by a night and subsequent day of sleep deprivation. Activity was standardized through modified suggested immobilization tests (mSITs).

SETTING

The study was conducted in a laboratory environment with a bedroom equipped for polysomnography during sleep and the mSITs.

PATIENTS

Nine patients (mean age 59.8+/-11.3 years [range: 33-72]; 4 males, 5 females) with clinically severe idiopathic RLS.

INTERVENTIONS

Patients were monitored with continuous ambulatory activity and core temperature recording. The mSITs were performed every three hours while subjects were awake. During the mSITs, subjective discomfort was measured every 15 minutes while motor restlessness was assessed through activity monitoring.

MEASUREMENTS AND RESULTS

Subjective discomfort and motor restlessness increased from a trough in the morning to a maximum at night in the hours following midnight. Peak intensity was found on the falling phase of the core temperature cycle, whose circadian rhythm appeared to be within the normal range for age.

CONCLUSIONS

An independent circadian factor modulates the intensity of RLS, which seems to peak on the falling phase of the core temperature cycle. Therefore, the diagnostic criteria that RLS occurs with rest and during the night have independent bases. Furthermore, RLS may be partially controlled by some process or substance whose level varies with the normal circadian rhythm.

Correction of chromosomal point mutations in human cells with bifunctional oligonucleotides

A sequence-specific genomic delivery system for the correction of chromosomal mutations was designed by incorporating two different binding domains into a single-stranded oligonucleotide. A repair domain (RD) contained the native sequence of the target region. A third strand-forming domain (TFD) was designed to form a triplex by Hoogsteen interactions. The design was based upon the premise that the RD will rapidly form a heteroduplex that is anchored synergistically by the TFD. Deoxyoligonucleotides were designed to form triplexes in the human adenosine deaminase (ADA) and p53 genes adjacent to known point mutations. Transfection of ADA-deficient human lymphocytes corrected the mutant sequence in 1-2% of cells. Neither the RD or TFD individually corrected the mutation. Transfection of p53 mutant human glioblastoma cells corrected the mutation and induced apoptosis in 7.5% of cells.

Human exonuclease 1 functionally complements its yeast homologues in DNA recombination, RNA primer removal, and mutation avoidance

Yeast exonuclease 1 (Exo1) is induced during meiosis and plays an important role in DNA homologous recombination and mismatch correction pathways. The human homolog, an 803-amino acid protein, shares 55% similarity to the yeast Exo1. In this report, we show that the enzyme functionally complements Saccharomyces cerevisiae Exo1 in recombination of direct repeat DNA fragments, UV resistance, and mutation avoidance by in vivo assays. Furthermore, the human enzyme suppresses the conditional lethality of a rad27Delta mutant, symptomatic of defective RNA primer removal. The purified recombinant enzyme not only displays 5'-3' double strand DNA exonuclease activity, but also shows an RNase H activity. This result indicates a back-up function of exonuclease 1 to flap endonuclease-1 in RNA primer removal during lagging strand DNA synthesis.

Intravenous granulocyte colony-stimulating factor increases the release of tumour necrosis factor and interleukin-1beta into the cerebrospinal fluid, but does not inhibit the growth of Streptococcus pneumoniae in experimental meningitis

Granulocyte colony-stimulating factor (G-CSF) possesses an antimicrobial effect in several animal models of infection. To evaluate a possible effect of G-CSF on the course of pneumococcal meningitis, rabbits infected intracisternally (i.c.) with Streptococcus pneumoniae type 3 (n = 7) received 50 microgram/kg of rhG-CSF intravenously (i.v.) 1 h prior to infection. Seven infected animals served as controls. Uninfected rabbits received 10 microgram of G-CSF (n = 3), 2 microgram G-CSF (n = 3) or saline (n = 3) i.c. G-CSF injected i.c. did not produce cerebrospinal fluid (CSF) leucocytosis. Compared with the control group, i.v. G-CSF given prior to i.c. infection increased the percentage of granulocytes in blood 6 h and 12 h after infection. Twelve hours after infection, CSF tumour necrosis factor (TNF) activity and CSF interleukin (IL)-1beta concentrations were significantly higher in G-CSF-treated animals. G-CSF did not decrease bacterial growth in the subarachnoid space and the CSF leucocyte densities were not influenced. At 24 h after infection, G-CSF did not reduce the CSF concentrations of neurone-specific enolase and the density of apoptotic neurones in the dentate gyrus of the hippocampus. In conclusion, i.v. G-CSF increased the concentration of pro-inflammatory cytokines in the CSF but did not decrease the growth of Streptococcus pneumoniae in the subarachnoid space.

ATP and phosphate reciprocally affect subunit association of human recombinant High Km 5'-nucleotidase. Role for the C-terminal polyglutamic acid tract in subunit association and catalytic activity

IMP-specific, High Km 5'-nucleotidase (EC 3.1.3.5) is an ubiquitous enzyme, the activity of which is highly regulated by substrate, ATP, and inorganic phosphate. The cDNA encoding this enzyme has recently been cloned and found to contain a unique stretch of nine glutamic and four aspartic acid residues at the C-terminus. To study the effects of this acidic tail, and of ATP and inorganic phosphate on enzyme function, we generated several structural modifications of the 5'-nucleotidase cDNA, expressed the corresponding proteins in Escherichia coli and compared their molecular and kinetic properties. As with the enzyme purified from human placenta, all recombinant proteins were activated by ATP and inhibited by inorganic phosphate. Although the S0.5-values were higher, the specific activities of the purified protein variants (except that truncated at the C-terminus) were similar. The molecular mass of the full-length enzyme subunit has been estimated at 57.3 kDa and the molecular mass of the native protein, as determined by gel-filtration chromatography, was estimated to be 195 kDa. Increasing the concentration of NaCl to 0.3 M promoted oligomerization of the protein and the formation of aggregates of 332 kDa. ATP induced further oligomerization to 715 kDa, while inorganic phosphate reduced the estimated molecular mass to 226 kDa. In contrast to the truncation of 30 amino acids at the N-terminus, which did not alter enzyme properties, the removal of the polyglutamic/aspartic acid tail of 13 residues at the C-terminus caused profound kinetic and structural changes, including a 29-fold decrease in specific activity and a significant increase in the sensitivity to inhibition by inorganic phosphate in the presence of AMP. Structurally, there was a dramatic loss of the ability to form oligomers at physiological salt concentration which was only partially restored by the addition of NaCl or ATP. These data suggest an important function of the polyglutamic acid tract in the process of association and dissociation of 5'-nucleotidase subunits.

Randomized trial of pamidronate in patients with thyroid cancer: bone density is not reduced by suppressive doses of thyroxine, but is increased by cyclic intravenous pamidronate

Patients taking suppressive doses of T4 are thought to have accelerated bone loss and increased risk of osteoporosis. We therefore randomize 55 patients taking suppressive doses of T4 to treatment with pamidronate (APD) 30 mg i.v. every 3 months for 2 yr (APD/T4), or placebo (placebo/T4). Patients had measurements of bone mineral density (BMD) of the spine, hip, radius, and total body every 6 months for 2 yr. There was no significant bone loss at any site in the placebo/T4 group. Ninety five percent confidence intervals excluded a rate of bone loss > 0.89%/yr for the spine and > 0.31%/yr at the total hip. When men were excluded from the analysis, there still was no significant bone loss for the placebo/T4 group, and confidence intervals did not change. The APD/T4 group showed increases in spine (4.3%, P = 0.0001), total hip (1.4%, P < 0.05), and trochanteric (3.0%, P = 0.0001) BMDs. In conclusion, premenopausal women and men on suppressive therapy with T4 do not lose bone rapidly, and are not at increased risk of developing osteoporosis. A regimen of 30 mg APD given every 3 months for 2 yr causes significant suppression of bone resorption and increases in BMD, and may be an acceptable alternative treatment for osteoporosis in patients who cannot tolerate oral bisphosphonates.

Moxifloxacin in the therapy of experimental pneumococcal meningitis

The activity of moxifloxacin (BAY 12-8039) against a Streptococcus pneumoniae type 3 strain (MIC and minimum bactericidal concentration [MBC] of moxifloxacin, 0.06 and 0.25 microgram/ml, respectively; MIC and MBC of ceftriaxone, 0.03 and 0.06 microgram/ml, respectively) was determined in vitro and in a rabbit model of meningitis. Despite comparable bactericidal activity, 10 micrograms of moxifloxacin per ml released lipoteichoic and teichoic acids less rapidly than 10 micrograms of ceftriaxone per ml in vitro. Against experimental meningitis, 10 mg of moxifloxacin per kg of body weight per ml reduced the bacterial titers in cerebrospinal fluid (CSF) almost as rapidly as ceftriaxone did (mean +/- standard deviation, -0.32 +/- 0.14 versus -0.39 +/- 0.11 delta log CFU/ml/h). The activity of moxifloxacin could be described by a sigmoid dose-response curve with a maximum effect of -0.33 delta log CFU/ml/h and with a dosage of 1.4 mg/kg/h producing a half-maximal effect. Maximum tumor necrosis factor activity in CSF was observed later with moxifloxacin than with ceftriaxone (5 versus 2 h after the initiation of treatment). At 10 mg/kg/h, the concentrations of moxifloxacin in CSF were 3.8 +/- 1.2 micrograms/ml. Adjunctive treatment with dexamethasone at 1 mg/kg prior to the initiation of antibiotic treatment only marginally reduced the concentrations of moxifloxacin in CSF (3.3 +/- 0.6 micrograms/ml). In conclusion, moxifloxacin may qualify for use in the treatment of S. pneumoniae meningitis.

Laparoscopic resection of an intra-abdominal cystic mass: a cystic mesothelioma

The clinical features of a patient with an intra-abdominal cystic mass do not lead to a specific diagnosis. Aspiration is usually ineffective because the mass recurs and cytologic investigation is often non-diagnostic. Conservative management is unsuccessful because symptoms often persist. Surgical management of cystic masses is required for definitive management and pathologic diagnosis. A laparoscopic approach to the diagnosis and treatment can provide essential anatomic information and a complete resection with minimal morbidity. A laparoscopic technique using 3 trocars and maintaining the integrity of the mass allows complete excision and removal of large intra-abdominal cystic masses as reported in a 43-year-old patient with a large intra-abdominal cystic mass identified as a benign cystic mesothelioma.

Glycerol does not reduce neuronal damage in experimental Streptococcus pneumoniae meningitis in rabbits

To study the effect of high-dose glycerol therapy on inflammation and neuronal destruction in a model of experimental pneumococcal meningitis, 14 New Zealand White rabbits were infected intracisternally with Streptococcus pneumoniae type 3. Sixteen hours after infection, 7 animals received intravenous glycerol therapy (1 g kg(-1) bolus and 0.5 g kg (1)h(-1) maintenance dose) and 7 animals served as untreated controls.After 8 h of therapy, the glycerol CSF:serum ratio exceeded the previously observed values in rabbits with an intact blood-CSF barrier (0.72+/-0.25 vs. 0.35), i.e. glycerol crossed the blood-CSF barrier more readily in animals altered by meningitis than in healthy animals. In contrast, the brain tissue:serum ratio of glycerol (grey matter 0.33+/-0.29, white matter 0.30+/-0.31) was substantially lower than the CSF:serum ratio (p=0.03 and p=0.047). There was no significant effect of glycerol on intracranial pressure, brain water content and neuron-specific enolase release into the CSF. Glycerol significantly increased the density of neuronal apoptosis in the dentate gyrus of the hippocampal formation. Therefore, glycerol does not appear to be beneficial in experimental pneumococcal meningitis.

Co-culture of synovial fibroblasts and differentiated U937 cells is sufficient for high interleukin-6 but not interleukin-1beta or tumour necrosis factor-alpha release

Inflamed synovium is characterized by high concentrations of cytokines [interleukin (IL)-6, IL-1beta and tumour necrosis factor (TNF)-alpha] and the abundant presence of infiltrated monocytes, many of which are found adjacent to the resident fibroblast-like synoviocytes. We have used a co-culture of fibroblast-like synoviocytes and differentiated U937 cells to study IL-6, IL-1beta and TNF-alpha release. After a 3 day co-culture, 35% of the U937 cells had adhered and were fully differentiated towards monocytes, as determined by expression of p47phox, CD14, MSE-1, Mac-1, collagenase and NADPH oxidase activity. IL-6 release from fibroblast-like synoviocytes was induced 4-fold by co-culture with differentiated U937 cells. However, co-culture of differentiated U937 cells with fibroblast-like synoviocytes failed to release detectable levels of IL-1beta and TNF-alpha from the U937 cells. Addition of synovial fluid further increased IL-6 release, but again had no effect on IL-1beta or TNF-alpha, although U937 cells differentiated by phorbol ester were able to release these two cytokines and, in the case of the co-culture, mRNAs for both cytokines were highly expressed in the U937 cells. We postulate that the influx of monocytes into the synovium is instrumental in the elevation of IL-6 levels, but this is not sufficient to explain high levels of IL-1beta or TNF-alpha.

Persistent chlorpromazine deposits in donor corneal tissue after corneal transplantation

PURPOSE

To present unusual cases with corneal graft deposits and discuss eye bank criteria concerning donors treated with phenothiazines.

METHODS

We examined two patients with unusual corneal graft deposits after uneventful corneal transplantation. Donors' files and eye bank procedures were reviewed.

RESULTS

Fine corneal endothelial punctate deposits were detected in both corneal grafts and did not resolve in the following 18 months.

CONCLUSION

To our knowledge, this is the first case report documenting transplantation of corneas with chlorpromazine deposits. Delicate corneal findings can be missed before transplantation.

Adjacent DNA elements dominantly restrict the ubiquitous activity of a novel chromatin-opening region to specific tissues

Locus control regions (LCRs) are thought to provide a dominant tissue-specific open chromatin domain that allows for proper gene regulation by enhancers/silencers and their associated transcription factors. Expression of the T-cell receptor alpha (TCR alpha) gene is limited to T cells and its locus exists in different chromatin configurations in expressing and nonexpressing cell types. Here we show that eight DNase I-hypersensitive sites in the TCR alpha locus comprise an LCR that confers T-cell compartment-specific expression upon a linked heterologous transgene. Removal of the three 5'-most hypersensitive sites of this LCR, containing TCR alpha enhancers/silencers, abolishes tissue-differential chromatin structure and results in transgene expression in all tissues examined. The remaining five DNase I-hypersensitive sites therefore constitute a novel control element possessing a widely active chromatin-opening function that allows for ubiquitous expression of a linked transgene in all transgenic founder mice. Furthermore, these data show that cis-acting elements without inherent LCR activity can dominantly modulate chromatin structure to determine tissue-specific gene expression in vivo.

Rifabutin for experimental pneumococcal meningitis

Rifabutin is a lipophilic antibacterial with high in vitro activity against many pathogens involved in bacterial meningitis including pneumococci. Resistance to beta-lactam antibiotics in pneumococci is not associated with a decreased sensitivity to rifabutin (30 strains from Germany with intermediate penicillin resistance; MIC range of penicillin: 0.125-1 mg/l, MIC of rifabutin: < 0.008-0.015 mg/l). Rifabutin at doses of 0.625, 1.25, 2.5, 5 and 10 mg/kg/h i.v. was investigated in a rabbit model of meningitis using a Streptococcus pneumoniae type 3 (MIC/MBC of rifabutin: 0.015/0.06 mg/l). The bacterial density in CSF at the onset of treatment was 7.3 +/- 0.6 log CFU/ml (mean +/- SD). Rifabutin decreased bacterial CSF titers in a dose-dependent manner [delta log CFU/ml/h (slope of the regression line log CFU/ml vs. time) at a dose of 0.625 mg/kg/h: -0.16 +/- 0.06 (n = 3), at 1.25 mg/kg/h: -0.20 +/- 0.12 (n = 4), at 2.5 mg/kg/h: -0.24 +/- 0.04 (n = 4), at 5 mg/kg/h: -0.31 +/- 0.10 (n = 8), and at 10 mg/kg/h: -0.29 +/- 0.10 (n = 5)]. At high doses rifabutin was as active as ceftriaxone at 10 mg/kg/h (delta log CFU/ml/h: -0.29 +/- 0.10, n = 10). Two and 5 h after initiation of therapy, CSF TNF-alpha activities were lower with rifabutin 5 mg/kg/h than with ceftriaxone (medians 2 vs. 141 U/ml, p = 0.005 at 2 h; median 51 vs. 120 U/ml 5 h after initiation of therapy, p = 0.04). This did not result, however, in a decrease of indicators of neuronal damage. In conclusion, intravenous rifabutin was bactericidal in experimental pneumococcal meningitis. Provided that a well-tolerated i.v. formulation will be available it may qualify as a reserve antibiotic for pneumococcal meningitis, in particular when strains with a reduced sensitivity to beta-lactam antibiotics are the causative pathogens.

Fatty foods and the risk of lung cancer: a case-control study from Uruguay

To examine whether fatty-food consumption modifies lung-cancer risk, a case-control study involving 377 patients with lung cancer and 377 controls was conducted in Uruguay. The study was restricted to men. Dietary patterns were assessed in detail using a 64-item food-frequency questionnaire, which allowed the calculation of total energy intake. After adjustment for potential confounders (body-mass index, family history of lung cancer, total energy intake and tobacco smoking), an increase in risk for fatty-food consumption was observed. In particular, fried foods (OR, 1.54; 95% CI, 1.01-2.35), dairy products (OR, 2.85; 95% CI, 1.73-4.69) and desserts (OR, 2.52; 95% CI, 1.54-4.12) were associated with increases in lung-cancer risk and significant dose-response patterns. The association with dairy products was more evident for adenocarcinoma of the lung (OR, 4.18; 95% CI, 1.87-9.36), whereas increased risks for fried-meat and dessert consumption were observed in each cell type. The association with fried-meat consumption was more pronounced for current smokers and for heavy smokers, whereas dairy products and desserts were associated with risk both in current and in past smokers. In conclusion, fat-rich foods and sucrose-rich foods were positively associated with an increased risk of lung cancer. Although the relationship between fat consumption and lung cancer has been reported, the direct association of lung cancer with sucrose-rich foods should be further investigated.

Is the automatic atrial defibrillator a promising approach?

Atrial fibrillation is a common arrhythmia, accounting for more consumption of medical resources than any other arrhythmia. The impact of the disease results from the combination of a loss of atrial contraction, and atrial control over cardiac rate. Studies in animals demonstrated the basic feasibility of atrial defibrillation using electrodes passed intravenously. Subsequent studies in patients confirmed that low-energy shocks were effective in converting atrial fibrillation and were safe if delivered synchronous to the R wave in the absence of a short preceding RR interval. Preliminary experience suggests that a small implanted device might provide beneficial therapy for patients with recurring episodes of persistent, drug-refractory, atrial fibrillation.

Treatment with growth hormone and IGF-I in growing rats increases bone mineral content but not bone mineral density

Human growth hormone (hGH) and insulin-like growth factor I (IGF-I) both stimulate bone formation and have been proposed as therapeutic agents for osteoporosis. We examined the effect of hGH and IGF-I alone and in combination on bone size, bone mineral content (BMC), and bone mineral density (BMD) in 10- to 12-week old growing female Sprague-Dawley rats. Sixty rats were assigned to treatment with either placebo, hGH, IGF-I, or both for 4 weeks. After 4 weeks, the right femurs and tibias were excised, and ex vivo BMC and the area of the tibia and femur were measured by dual-energy X-ray absorptiometry (DXA); volume of these bones was measured by Archimedes' principle. In addition, proximal tibial bone density was measured directly by peripheral quantitative computerized tomography (pQCT). Bone length, area, and volume in all treated groups was greater than controls. Areal bone density by DXA (BMC/area) was higher in IGF-treated rats and lower in GH-treated rats than in controls. Volumetric bone density (BMC/volume) was lower in treated groups than in controls. Measurements by pQCT confirmed that true bone density was lower in all treated groups than in controls. We conclude that treatment with hGH or IGF-I increased bone size and mineral content but decreased bone density in growing rats. Because areal correction of BMC did not adequately correct for the increased bone volume in IGF-treated rats, results of areal bone density by DXA should be interpreted with caution when treatment causes a disparity in bone size between groups.