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Objectives Intrathecal baclofen (ITB) is a cost-effective therapy for patients with severe spasticity. The most common complications are catheter-related complications (CRCs) including kinking/occlusion, blockage, migration, fracture, disconnection, and CSF leak. Our objective was to determine the CRC rate in a large cohort of adults with newly implanted ITB pump systems with polymer reinforced silicone catheters. Materials and methods This is a retrospective study of a prospectively maintained database consisting of patients who had undergone implantation of ITB pump systems with Ascenda (Medtronic, Minneapolis) catheters from 2013 to 2020. Over this seven-year period, 141 patients underwent ITB pump system implantations; 126 of which had a minimum of one-year follow-up. Results The 126 patients with a minimum of one year follow-up (average 43 month; range 12-89), had an average age of 51 years (63% male). Severe spasticity was due to spinal cord injury (38%), traumatic brain injury (15%), cerebral palsy (13%), multiple sclerosis (11%), stroke (10%), and other (13%). Nine (7.1%) CRCs occurred in 7 (5.6%) patients (median 6 mo. post-implant): 5 intrathecal catheter occlusions (range 3-52 months post-implant), two fractures in one patient (6 months), one disconnection at the catheter pump interface (2 months), and one due to kinking at 84 months No migrations occurred. Conclusions Reported CRCs have been high for ITB pump systems. Ours is the first large cohort, long-term study of CRCs related to reinforced catheters; additionally, our low CRC rate compares favorably to previously published data. Thus, implantation of reinforced catheters may be associated with a low CRC rate.

The presenting report describes the use of a posterior cranial vault distraction procedure in resolving a Chiari malformation with associated syringomyelia following a surgically-treated nonsyndromic craniosynostosis. Chiari malformations are typically treated with posterior fossa decompression with or without expansion duraplasty. The objective of this report is to describe the effectiveness in resolving both Chiari malformation and secondary syringomyelia with posterior cranial vault distraction osteogenesis. A 5-year-old male, with a history of surgery for sagittal synostosis during infancy, presented with daily severe headaches and dysesthesias in the hands and feet. Imaging demonstrated a copper-beaten calvarium and a Chiari 1 malformation with a 7 mm diameter C4-T1 syrinx. He underwent posterior cranial vault distraction osteogenesis over 3 months to increase his intracranial volume. The patients' headaches improved significantly, and his dysesthesias resolved postoperatively. A magnetic resonance imaging performed 7 months after completion of distraction demonstrated resolution of the Chiari malformation and decompression of his syrinx. A computed tomography scan at 9 months postdistraction showed resolution of the copper-beaten calvarium. Patients with a history of craniosynostosis can develop inadequate cranial volume over time due to abnormal skull growth, leading to secondary Chiari malformation with or without syringomyelia. Posterior vault distraction is an effective strategy to address these conditions and can be employed later in childhood to treat the underlying pathology. The mechanism potentially expands both calvarium and dura, which in turn addresses both the Chiari malformation and secondary syringomyelia.

Background: Clinical documentation of patient care alters coding accuracy of Medicare Severity Diagnosis-Related Groups (MS-DRGs), expected mortality, and expected length of stay (LOS) which impact quality metrics. We aimed to determine if neurosurgical quality metrics could be improved by facilitating accurate documentation and subsequently developed a mobile application and educational video to target areas of opportunity. Methods: Vizient software was used to analyze MS-DRGs and expected LOS for sample of patients requiring surgery for spinal pathology, brain tumors, and subarachnoid hemorrhage (SAH) between January 2019 and August 2021. Chart reviews were conducted to discover variables missed by documenting provider and/or coder. Results: Review of 114 spinal surgeries, 20 brain tumors, and 53 SAH patients revealed at least one additional variable impacting LOS in 43% of spine, 75% of brain tumor, and 92% of SAH patients, with an average of 1 (1.25), 2 (1.75), and 3 (2.89) new variables, respectively. Recalculated expected LOS increased by an average of 0.86 days for spine, 3.08 for brain tumor, and 6.46 for SAH cases. Conclusion: Efforts to accurately document patient care can improve quality metrics such as expected LOS, mortality, and cost estimates. We determined several missing variables which impact quality metrics, showing opportunity exists in neurosurgical documentation improvement. Subsequently, we developed an educational video and mobile-supported application to specifically target these variables. To the best of our knowledge, this represents the first initiative to utilize the proven powers of mobile phones in health care toward the novel application of specifically improving neurosurgical quality metrics.

Background: The most common neuroradiological finding in pediatric nonaccidental trauma (NAT) is subdural hematoma (SDH). Management options for pediatric SDH range from conservative clinical surveillance to craniotomy or decompressive craniectomy. The middle meningeal artery (MMA) indirectly feeds the hematoma; thus, MMA embolization is an alternative or adjunct to current surgical treatments in adults. Herein, we present, to the best of our knowledge, the first reported case of successful MMA embolization in a pediatric patient as an adjunct to current standard treatment for chronic SDH (cSDH). Case Description: An 18-month-old male with a history of NAT presented at 5 months of age with an acute right parietal skull fracture and bilateral SDH treated with burr hole drainage. He was lost to follow-up until 15 months of age with an increased head circumference and new dysconjugate gaze. Imaging revealed a right-sided cSDH and underwent craniotomy. Six-week follow-up revealed significant improvement in the SDH but cSDH remained at the periphery of the craniotomy’s reach. The patient symptoms continued. The right-sided MMA embolization was offered as option to avoid repeat craniotomy. Follow-up CTs at 2 weeks, 3 months, and 6 months postprocedure revealed decrease of cSDH size and density. At 8-month follow-up, the patient continued to meet developmental milestones with near resolution of his dysconjugate gaze. Conclusion: This case report details the first successful use of MMA embolization in the treatment of pediatric cSDH as an adjunct to standard treatment. Further investigation of MMA embolization in pediatrics should be made to expand options available for cSDH in this patient population.

Importance Symptom-based methods of concussion diagnosis in contact sports result in underdiagnosis and repeated head injury exposure, increasing the risk of long-term disability. Measures of neuro-ophthalmologic (NO) function have the potential to serve as objective aids, but their diagnostic utility is unknown. Objective To identify NO measures that accurately differentiate athletes with and without concussion. Design, setting, and participants This cohort study was conducted among athletes with and without concussion who were aged 17 to 22 years between 2016 and 2017. Eye movements and cognitive function were measured a median of 19 days after injury among patients who had an injury meeting the study definition of concussion while playing a sport (retrospectively selected from a concussion clinic), then compared with a control group of participants without concussion (enrolled from 104 noncontact collegiate athlete volunteers without prior head injury). Data analysis was conducted from November 2019 through May 2020. Exposure Concussion. Main outcomes and measures Classification accuracy of clinically important discriminator eye-tracking (ET) metrics. Participants' eye movements were evaluated with a 12-minute ET procedure, yielding 42 metrics related to smooth pursuit eye movement (SPEM), saccades, dynamic visual acuity, and reaction time. Clinically important discriminator metrics were defined as those with significantly different group differences and area under the receiver operator characteristic curves (AUROCs) of at least 0.70. Results A total of 34 participants with concussions (mean [SD] age, 19.7 [2.4] years; 20 [63%] men) and 54 participants without concussions (mean [SD] age, 20.8 [2.2] years; 31 [57%] men) completed the study. Six ET metrics (ie, simple reaction time, discriminate reaction time, discriminate visual reaction speed, choice visual reaction speed, and reaction time on 2 measures of dynamic visual acuity 2) were found to be clinically important; all were measures of reaction time, and none were related to SPEM. Combined, these 6 metrics had an AUROC of 0.90 (95% CI, 0.80-0.99), a sensitivity of 77.8%, and a specificity of 92.6%. The 6 metrics remained significant on sensitivity testing. Conclusions and relevance In this study, ET measures of slowed visual reaction time had high classification accuracy for concussion. Accurate, objective measures of NO function have the potential to improve concussion recognition and reduce the disability associated with underdiagnosis.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease leading to recurrent epistaxis, telangiectasias, and/or visceral arteriovenous malformations. Multiple treatment methods, including both pharmacologic and surgical, are described to be effective in managing symptomatic HHT. Few report the duration of symptom improvement for each of these treatment methods. This study aims to analyze the duration of effectiveness of coblation treatment for recurrent epistaxis in those with HHT.Retrospective single-center chart review was completed for patients diagnosed with HHT who underwent coblation treatment by the same otolaryngologist from December 2009 to November 2021. Demographic information was collected along with whether local Bevacizumab was used during each treatment. Months between treatment coblation sessions was used as a surrogate for duration of treatment effectiveness. Descriptive statistics were used for analysis alongside quantitative statistical analysis.Over the course of 12 years, 57 patients (24 female, 42.11%) with HHT underwent a total number of 150 coblation treatments. The average age at initial coblation was 59 years (29-88) with an average follow-up time of 5 years (1-12 years). Of the 150 coblations, 30 treatments (20%) included bevacizumab injections into the nasal cavity. The average duration of treatment effectiveness across all 150 treatment sessions was 24.5 months (1-87 months). Of the 26 patients (46%) that underwent multiple coblation treatments, the overall average duration of coblation effectiveness was 16.4 months (1-72 mos). When Bevacizumab was utilized, the average duration of effectiveness was 18.3 months (3-62 mos), while the average duration of effectiveness for treatments without Bevacizumab was 15.7 months (1-87 mos, p 0.251). Further, there was no correlation between duration of treatment effectiveness and age, sex, and race; yet,there was a significant negative correlation between the use of tobacco and duration of coblation effectiveness (p = 0.0202).Coblation is an effective treatment option for the management of epistaxis in patients with HHT with duration of benefit lasting approximately 2 years. The use of Bevacizumab did not add to the duration of treatment benefit. Further, the duration of benefit was negatively impacted by smoking history.

Background: Arachnoid cysts (ACs) are cerebrospinal fluid-containing cysts located between the surface of the brain or spinal cord and arachnoid layer of the leptomeninges. ACs have been known to cause cognitive, language, and behavioral deficits and currently there is no standard treatment paradigm. Surgical indications include papilledema, increasing growth with mass effect causing neurological deficit, or rapid head growth, however, cognitive symptoms related to mass effect may not always be considered. Case Description: We present a 3-year-old male with an AC of the left anterior fossa causing frontal lobe compression with resultant behavioral, language, and cognitive deficits. Conclusion: Surgical intervention for AC decompression may be indicated when there are cognitive, behavioral, or language delays related to the mass effect and location of the AC. Neuropsychiatric testing or more advanced imaging studies may further support surgical treatment. After craniotomy for fenestration of the left frontal AC, there was drastic improvement in cognitive, language, and behavioral symptoms in our pediatric patient.

For a nonlinear hyperbolic equation with variable coefficients and the infinite-dimensional Levy Laplacian ΔL, $$\beta \left( {\sqrt 2 \left\| x \right\|_H \frac{{\partial U(t,x)}} {{\partial t}}} \right)\frac{{\partial ^2 U(t,x)}} {{\partial t^2 }} + \alpha (U(t,x))\left[ {\frac{{\partial U(t,x)}} {{\partial t}}} \right]^2 = \Delta _L U(t,x),$$ we present algorithms for the solution of the boundary-value problem U(0, x) = u0, U(t, 0) = u1 and the exterior boundary-value problem U(0, x) = v0, \(\left. {U(t,x)} \right|_{\Gamma = v_1 }\), \(\lim _{\left\| x \right\|_{H \to \infty } } \left. {U(t,x) = v_2 } \right|\) for the class of Shilov functions depending on the parameter t.

We present solutions of the boundary-value problem $$ U\left( {0,x} \right)={u_0},\,\,\,\,U\left( {t,0} \right)={u_1} $$ and the external boundary-value problem $$ U\left( {0,x} \right)={v_0},\,\,\,\,\,U\left( {t,x} \right){|_{\varGamma }}={v_1},\,\,\,\,\mathop{\lim}\limits_{{\left\| x \right\|H\to \infty }}U\left( {t,x} \right)={v_2} $$ for the nonlinear hyperbolic equation $$ \frac{{{\partial^2}U\left( {t,x} \right)}}{{\partial {t^2}}}+\alpha \left( {U\left( {t,x} \right)} \right){{\left[ {\frac{{\partial U\left( {t,x} \right)}}{{\partial t}}} \right]}^2}={\varDelta_L}U\left( {t,x} \right) $$ with infinite-dimensional Levy Laplacian Δ L

We propose an algorithm for the solution of the boundary-value problem $$ U\left( {0,x} \right) = {u_0},\,\,\,\,U\left( {t,0} \right) = {u_1} $$ and the external boundary-value problem $$ U\left( {0,x} \right) = {\upsilon_0},\,\,\,\,{\left. {U\left( {t,x} \right)} \right|_{\Gamma }} = {\upsilon_1},\,\,\,\,\mathop{{\lim }}\limits_{{{{\left\| x \right\|}_{{H \to \infty }}}}} U\left( {t,x} \right) = {\upsilon_2} $$ for the nonlinear hyperbolic equation $$ \frac{\partial }{{\partial t}}\left[ {k\left( {U\left( {t,x} \right)} \right)\frac{{\partial U\left( {t,x} \right)}}{{\partial t}}} \right] = {\Delta_L}U\left( {t,x} \right) $$ with divergent part and infinite-dimensional Levy Laplacian ∆ L .

We present the solutions of boundary-value and initial boundary-value problems for a nonlinear parabolic equation with Levy Laplacian ∆ L resolved with respect to the derivative $$ \frac{{\partial U\left( {t,x} \right)}}{{\partial t}} = f\left( {U\left( {t,x} \right),{\Delta_L}U\left( {t,x} \right)} \right) $$ in fundamental domains of a Hilbert space.

Background About 70–80 percent of patients with acute myeloid leukemia enter complete remission, but at least half of these patients who achieve remission go on to relapse. Improved treatment is likely to come from increasing the time to relapse, especially for younger patients. With the vastly increasing number of targeted therapies there is a strong need for short-term end-points to efficiently test such therapies for further pursuance. Minimal residual disease assessment may offer such an end-point since it is a strong independent prognostic factor. As proof of principle we examined this concept for FLT3-ITD status at diagnosis.Design and Methods We determined FLT3-ITD status in bone marrow samples from 196 patients with newly diagnosed acute myeloid leukemia. The frequencies of residual leukemic cells of these 196 patients were assessed in 267 follow-up bone marrow samples using immunophenotypic assessment of minimal residual disease.Results The median frequency of residual leukemic cells after the first cycle of chemotherapy was 8.5-fold higher in patients with FLT3-ITD than in those with wild type FLT3. Such a difference translates into differences in survival, even if other potentially outcome-modulating mutations, such as NPM1, KIT, NRAS, KRAS, FLT3-exon 20 and PTPN11 are included in the analysis.Conclusions This study shows that it could be possible to study the efficacy of FLT3 inhibitors using the level of minimal residual disease as a short-term end-point.

We construct a Dirichlet form associated with the infinite dimensional Lévy–Laplace operator. We show that there exists a natural connection between this form and a Markov process.

A solution to the Cauchy problem for a rather general class of nonlinear parabolic equations involving the infinite-dimensional Laplacian ΔL of the form \(f(U(t,x),\frac{\partial U(t,x)}{\partial t},\Delta_{L}U(t,x))=0\) , where f is a real function defined on R3 is presented.

Purpose: Several studies have shown survival benefit by autologous stem cell transplantation in acute myeloid leukemia (AML) after purging of grafts. This has, however, not been confirmed in randomized studies due to high toxicity of purging modalities for normal progenitor/stem cells. In this study, we investigated whether positive selection for CD34+ and/or CD133+ cells, which results in high recovery of normal progenitor/stem cells, is applicable for purging AML grafts. Experimental Design: Positive selections of normal stem cells using CD34 and/or CD133 can be done if one or both markers are absent or have dim expression and remain so during the course of the disease. Marker expressions in newly diagnosed AML were measured with flow cytometry using a cutoff value for positivity of 1%. Stability of marker expression was studied by pairwise comparison of material at diagnosis and relapse. Leukemia associated phenotype expression was used to measure the efficacy of tumor cell reduction. Results: In newly diagnosed AML (n = 165), we found no CD34 and/or CD133 expression in 32% of the cases and dim expression in 20% of the cases. No increase in the percentage of CD34+ cells (n = 44) and CD133+ cells (n = 29) was found in corresponding relapses. Positive selection using grafts contaminated with AML blasts, showing either no or dim expression of CD34 or CD133, resulted in a 3 to 4 log tumor cell reduction (n = 11) with median 50% recovery of normal stem cells. Conclusions: Purging by positive selection of CD34+ and/or CD133+ cells can safely, effectively, and reproducibly be applied in about 50% of AML cases.

Purpose: Apoptosis is an important mechanism regulating survival of acute myeloid leukemia cells. The apoptosis-related protein profile at diagnosis is important for achieving complete remission thereby affecting survival variables such as disease-free survival (DFS) and overall survival (OS). To investigate the role of the apoptosis protein profile in further response to therapy and outgrowth of disease. Experimental Design: We studied whether Bcl-2, Bcl-xL, Mcl-1, Bax as well as the Bcl-2/Bax ratio and a combination of all (antiapoptosis index, AAI) are related to the frequency of malignant cells surviving the chemotherapy (i.e., minimal residual disease, MRD). MRD cells were identified by leukemia-associated aberrant phenotypes established at diagnosis by flow cytometry. Results: We found that Bcl-2 (R = 0.55, P = 0.002), Bcl-2/Bax (R = 0.42, P = 0.02), and AAI (R = 0.47, P = 0.01) at diagnosis directly correlated with MRD after the first cycle of chemotherapy. In turn, MRD frequency after first cycle correlated with DFS (P = 0.04). Taken together, these results directly explain why Bcl-2/Bax and especially AAI (P = 0.007) at diagnosis correlate with DFS. Conclusion: Our results show that apoptosis resistance plays an important role in the first stage of the therapy (i.e., to eliminate the bulk of malignant cells), in terms of achievement of complete remission and frequency of MRD after first cycle of therapy.

Acute myeloid leukemia (AML) has a poor prognosis due to treatment-resistant relapses. A humanized anti-CD33 antibody (Mylotarg) showed a limited response rate in relapsed AML. To discover novel AML antibody targets, we selected a panel of single chain Fv fragments using phage display technology combined with flow cytometry on AML tumor samples. One selected single chain Fv fragment broadly reacted with AML samples and with myeloid cell lineages within peripheral blood. Expression cloning identified the antigen recognized as C-type lectin-like molecule-1 (CLL-1), a previously undescribed transmembrane glycoprotein. CLL-1 expression was analyzed with a human anti-CLL-1 antibody that was generated from the single chain Fv fragment. CLL-1 is restricted to the hematopoietic lineage, in particular to myeloid cells present in peripheral blood and bone marrow. CLL-1 is absent on uncommitted CD34+/CD38− or CD34+/CD33− stem cells and present on subsets of CD34+/CD38+ or CD34+/CD33+ progenitor cells. CLL-1 is not expressed in any other tissue. In contrast, analysis of primary AMLs demonstrated CLL-1 expression in 92% (68 of 74) of the samples. As an AML marker, CLL-1 was able to complement CD33, because 67% (8 of 12) of the CD33− AMLs expressed CLL-1. CLL-1 showed variable expression (10–60%) in CD34+ cells in chronic myelogenous leukemia and myelodysplastic syndrome but was absent in 12 of 13 cases of acute lymphoblastic leukemia. The AML reactivity combined with the restricted expression on normal cells identifies CLL-1 as a novel potential target for AML treatment.

We report a likely false-positive phencyclidine (PCP) result detected with a urine drug screen (UDS) (Medtox, St Paul, Minnesota, USA) in the setting of therapeutic desvenlafaxine (Pristiq) use. Desvenlafaxine (O-desmethylvenlafaxine) is the active metabolite of venlafaxine (Effexor). Prior reports have confirmed venlafaxine use resulting in a false-positive for PCP on a UDS. However, there has been a paucity of reporting of commercially available desvenlafaxine formulations (Pristiq, Khedezla) resulting in false-positives for PCP on a UDS.

We present a method for the solution of the Cauchy problem for three broad classes of nonlinear parabolic equations $$\frac{{\partial U\left( {t,x} \right)}}{{\partial t}} = f\left( {\Delta _L U\left( {t,x} \right)} \right), \frac{{\partial U\left( {t,x} \right)}}{{\partial t}} f\left( {t,\Delta _L U\left( {t,x} \right)} \right),$$ and $$\frac{{\partial U\left( {t,x} \right)}}{{\partial t}} = f\left( {U\left( {t,x} \right), \Delta _L U\left( {t,x} \right)} \right)$$ with the infinite-dimensional Laplacian ΔL.

We present a method of solving for the nonlinear equationf(U(x),Δ 2 U(x)) = Δ L U(x) (Δ L is an infinite-dimensional Laplacian) unresolved with respect to an iterated infinite-dimensional Laplacian and for the Riquier problem for this equation.

Solutions are found for the nonlinear equation Δ 2 U(x) = f(U(x)) (here, Δ L is an infinite-dimensional Laplacian) which is solved with respect to the iterated infinite-dimensional Laplacian. The Riquier problems are stated for an equation of this sort.

CUTE MYELOID leukemia (AML) in adults is responA sive to chemotherapy in approximately 65% of the patients. To date only 30% to 35% of the patients can be cured with chemotherapy alone because of the emergence of malignant cell populations, which are resistant to all clinically available anticancer drugs. One cause of tumor cell resistance to natural product related anticancer agents, such as the anthracyclines, vinca alkaloids, and etoposide, may be the overexpression of the MDR1-encoded plasma membrane drug transporter P-gl y coprotein (Pgp/MDR I), ’,’ If one focuses on adult acute leukemic disorders such as AML and acute lymphocytic leukemia (ALL), there is not yet a curative standard treatment.3 One factor studied extensively as a possible contributor to chemotherapy failure in leukemias is the PgplMDR1 phenotype. Such studies have provided quite firm evidence that PgpJMDR1 overexpression is relatively abundant in primary, treatment refractory and in relapsed le~kemias.~.~ Moreover, complete remission rates were significantly lower in de novo AML overexpressing MDRl mRNA or Pgp.4-7 However, a recent overview of published data for AML concluded that the effect of Pgp on the outcome was weak (relative risk of 0.68 for complete remission).’ This analysis included the results of the two largest studies performed, published as abstracts, which report that Pgp expression is not a prognostic factor in AML. Many of these studies rely on mRNA detection (Northern blotting, RNase protection, or polymerase chain reaction [PCR]) and/or detection of Pgp protein (immunocytochemistry, flow cytometry, immunoblotting) and express the results as positive or negative by choosing an arbitrarily set cut-off point.’ However, drug-resistance levels are more likely to be a continuous variable rather than that tumor cells are simply positive or negative for a particular resistance mechanism. A second point to be considered is that the establishment of the relevance of the function of Pgp in clinical multidrug resistance (MDR) will probably require multicentered prospective clinical studies. Results of MDR assays have to be correlated with patients’ responses to treatment. Therefore, “to be successful, a concerted effort will be DNR (117%. N = 21), but was higher for vincristine in every single case (161% ~121%. N = 22; P< .OOl), indicating additional verapamil effects, not related to Pgp. The correlation of the staining of viable cells for Pgp with the monoclonal antibody MRK16 was r = .77 (N = 52) for the R123/PSC833 functional test and r = .84 (N = 501 for the DNR/PSC833 test. From these results it could be calculated that a maximal increase of the mean DNR accumulation of about 50% can be achieved by blocking Pgp pump activity with PSC833 in leukemic blast samples with the highest mean Pgp expression. Subpopulations of blast cells with higher Pgp activity are likely to be present. Their relevance has to be studied further.The methods outlined here allow the reliable, quantitative monitoring of the PgpIMDRl phenotype in leukemias in multicentered, clinical Pgp modulation studies. 0 1996 by The American Society of Hematology. needed to standardize reporting and quality control between participating laboratories” .lo The need for such quality control studies in the MDR field has become increasingly clear from two interlaboratory MDR methods workshops held in 1994, one in France and one in Memphis, TN. Major discrepancies were found in the results of PgpJMDR1 detection in

We propose a method for the solution of the nonlinear equationf(U(x),ΔU(x))=F(x) (ΔL is an infinite-dimensional Laplacian, ΔLU(x)=γ, γ≠0) unsolved with respect to the infinite-dimensional Laplacian, and for the solution of the Dirichlet problem for this equation.

Multidrug resistance (MDR) in tumour cells is often caused by the overexpression of the plasma membrane drug transporter P-glycoprotein (P-gp) or the recently discovered multidrug resistance-associated protein (MRP). In this study we investigated the specificity and sensitivity of the fluorescent probes rhodamine 123 (R123), daunorubicin (DNR) and calcein acetoxymethyl ester (calcein-AM) in order to detect the function of the drug transporters P-gp and MRP, using flow cytometry. The effects of modulators on the accumulation and retention of these probes were compared in several pairs of sensitive and P-gp- as well as MRP-overexpressing cell lines. R123, in combination with the modulator PSC833, provided the most sensitive test for detecting P-gp-mediated resistance. Moreover, in a 60 min drug accumulation assay R123 can be regarded as a P-gp-specific probe, since R123 is not very efficiently effluxed by MRP. In contrast to R123, a 60 min DNR or calcein-AM accumulation test could be used to detect MRP-mediated resistance. The MRP-specific modulator genistein could be used in combination with DNR, but not with calcein-AM. Vincristine (VCR) can be used to increase the cellular uptake of calcein-AM in MDR cells, but is not specific for MRP. Thus, although the combination of DNR with genistein appeared to be as sensitive as the combination of calcein-AM with VCR, the former may be used to probe specific MRP activity whereas the latter provides a combined (P-gp + MRP) functional MDR parameter. With these functional assays the role and relative importance of P-gp and MRP can be studied in, for example, haematological malignancies.

A criterion of harmonicity of functions in a Hilbert space is given in the case of nonnegative second derivatives without using an assumption that they are mutually independent. This assumption is replaced by a weaker condition.

A criterion of harmonicity of functions in a Hilbert space is given in the case of weakened mutual dependence of the second derivatives.

Formation of lactate and pyruvate from glucose was studied in cultured amniocytes and chorionic villus fibroblasts from controls, either untreated or treated with azide, an inhibitor of cytochrome c oxidase, or other inhibitors of the mitochondrial respiratory chain. Amniocytes with an established cytochrome c oxidase deficiency were also investigated. Control amniocytes treated with azide as well as cytochrome c oxidase deficient amniocytes displayed strongly increased lactate-to-pyruvate ratios after incubation with glucose, compared to control cells. Elevated lactate-to-pyruvate ratios were also found in chorionic villus fibroblasts in which complexes I, III or IV were inhibited by rotenone, antimycin or azide, respectively. We conclude that measurement of lactate and pyruvate production from glucose in cultured amniocytes and/or chorionic villus fibroblasts allows adequate prenatal diagnosis of systemic cytochrome c oxidase deficiency and presumably of other systemic deficiencies of mitochondrial respiratory chain enzymes.

There are exceptionally many harmonic functions of an infinite number of variables. Using for the estimate of the infinite-dimensional Laplacian introduced by P. Levy, estimates of the germ of sums of orthogonal random variables, there are obtained optimal (in a certain sense) conditions of the harmonicity of the functions in a Hilbert space. Along with harmonicity conditions obtained earlier based on estimates of the germ of sums of dependent random variables, they allow one to encompass the manifold of harmonic functions of an infinite number of variables.

In CD34+ acute myeloid leukemia (AML), the malignant stem cells reside in the CD38+ compartment. We have shown before that the frequency of such CD34+CD38- cells at diagnosis correlates with minimal residual disease (MRD) frequency after chemotherapy and with survival. Specific targeting of CD34+CD38+ cells might thus offer therapeutic options. Previously, we found that C-type lectin-like molecule-1 (CLL-1) has high expression on the whole blast compartment in the majority of AML cases. We now show that CLL-1 expression is also present on the CD34+CD38- stem-cell compartment in AML (77/89 patients). The CD34+CLL-1+ population, containing the CD34 +CD38-CLL-1+ cells, does engraft in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice with outgrowth to CLL-1+ blasts. CLL-1 expression was not different between diagnosis and relapse (n = 9). In remission, both CLL-1- normal and CLL-1 + malignant CD34+CD38- cells were present. A high CLL-1+ fraction was associated with quick relapse. CLL-1 expression is completely absent both on CD34+CD38- cells in normal (n = 11) and in regenerating bone marrow controls (n = 6). This AML stem-cell specificity of the anti-CLL-1 antibody under all conditions of disease and the leukemia-initiating properties of CD34+CLL-1+ cells indicate that anti-CLL-1 antibody enables both AML-specific stem-cell detection and possibly antigen-targeting in future.

The Lévy Laplacian is an infinite-dimensional generalization of the well-known classical Laplacian. The theory has become well developed in recent years and this 2005 book was the first systematic treatment of the Lévy-Laplace operator. The book describes the infinite-dimensional analogues of finite-dimensional results, and more especially those features which appear only in the generalized context. It develops a theory of operators generated by the Lévy Laplacian and the symmetrized Lévy Laplacian, as well as a theory of linear and nonlinear equations involving it. There are many problems leading to equations with Lévy Laplacians and to Lévy-Laplace operators, for example superconductivity theory, the theory of control systems, the Gauss random field theory, and the Yang–Mills equation. The book is complemented by an exhaustive bibliography. The result is a work that will be valued by those working in functional analysis, partial differential equations and probability theory.

Purpose: In CD34-positive acute myeloid leukemia (AML), the leukemia-initiating event originates from the CD34+CD38− stem cell compartment. Survival of these cells after chemotherapy may lead to minimal residual disease (MRD) and subsequently to relapse. Therefore, the prognostic impact of stem cell frequency in CD34-positive AML was investigated. Experimental Design: First, the leukemogenic potential of unpurified CD34+CD38− cells, present among other cells, was investigated in vivo using nonobese diabetic/severe combined immunodeficient mice transplantation experiments. Second, we analyzed whether the CD34+CD38− compartment at diagnosis correlates with MRD frequency after chemotherapy and clinical outcome in 92 AML patients. Results: In vivo data showed that engraftment of AML blasts in nonobese diabetic/severe combined immunodeficient mice directly correlated with stem cell frequency of the graft. In patients, a high percentage of CD34+CD38− stem cells at diagnosis significantly correlated with a high MRD frequency, especially after the third course of chemotherapy. Also, it directly correlated with poor survival. In contrast, total CD34+ percentage showed no such correlations. Conclusions: Both in vivo data, as well as the correlation studies, show that AML stem cell frequency at diagnosis offers a new prognostic factor. From our data, it is tempting to hypothesize that a large CD34+CD38− population at diagnosis reflects a higher percentage of chemotherapy-resistant cells that will lead to the outgrowth of MRD, thereby affecting clinical outcome. Ultimately, future therapies should be directed toward malignant stem cells.

Summary Background In a previous study we applied doxorubicin and cyclophosphamide in a dose-intensive regimen with GM-CSF to patients with metastatic breast cancer (MBC). That treatment failed to prolong the remission duration compared to conventional-dose chemotherapy. In the present study we escalated the dosages of the same agents to: 1) determine the maximum tolerated dosages (MTD) when given for three cycles with G-CSF mobilised peripheral blood progenitor cell (PBPC) reinfusion and 2) evaluate the antitumour effect of this regimen. Patients and methods For mobilisation of PBPC, G-CSF 15 μg/kg/day was given subcutaneously (s.c.), and in subsequent cohorts leucapheresis was started on days 3, 4 or 6. The intention was to treat MBC patients with three cycles of doxorubicin and cyclophosphamide at a starting dose of doxorubicin 90 mg/m2 and cyclophosphamide 1000 mg/m2 Dosages were then escalated in subsequent cohorts of at least three patients. In case of dose-limiting mucositis, only the dose of cyclophosphamide was escalated in the next cohort. Results Twenty-one patients entered this protocol, of which 18 patients received high-dose chemotherapy. The mobilisation of PBPC using G-CSF only was sufficient for three cycles of high-dose chemotherapy in 10 of 21(47%) patients. Mucositis precluded dose escalation of doxorubicin beyond 110 mg/m2 The MTD in this combination was 110 mg/m for doxorubicin, and 4 g/m for cyclophosphamide, with haemorrhagic cystitis being the dose-limiting toxicity. The overall response rate was 78% (95% confidence interval (95% CI): 57%–97%), with 22% (95% CI: 3%–4l%) complete responses. Conclusions The MTD of this three cycle high-dose regimen was doxorubicin 110 mg/m and cyclophosphamide 4 g/m2 with mucositis and cystitis being dose-limiting toxicities. Although the primary aim was not the evaluation of antitumour effect, this high-dose regimen does not appear to provide an improvement of treatment results in comparison with our previous study with the same drugs at moderately high-dosages without stem cell support.

We have compared multiple assays for the P-glycoprotein (Pgp/MDR1) phenotype in fresh and thawed adult acute leukemia to validate and quantitate measures for the expression and function of Pgp. The results are related to the Pgp-expressing KB8 and KB8-5 call lines. The most sensitive assay was the measurement of modulation of the rhodamine 123 (R123) fluorescence by 2 micromol/L PSC833, followed by the modulation of the probe calcein-AM. We also found a good intralaboratory and interlaboratory correlation between the values of the R123/PSC833 assay for fresh as well as thawed samples. In addition, the affects of PSC833 on 3H-daunorubicin (DNR) accumulation, DNR fluorescence, and 3H-vincristine accumulation were very similar. The correlation between the DNR/PSC833 and R123/PSC833 test was r = .86 (N = 51). The modulation of drug accumulation by 8 micromol/L verapamil was the some as the PSC833 effect for DNR (117%, N = 21), but was higher for vincristine in every single case (161% v 121%, N = 22; P.001), indicating additional verapamil effects, not related to Pgp. The correlation of the staining of viable cells for Pgp with the monoclonal antibody MRK16 was r = .77 (N = 52) for the R123/PSC833 functional test and r = .84 (N = 50) for the DNR/PSC833 test. From these results it could be calculated that a maximal increase of the mean DNR accumulation of about 50% can be achieved by blocking Pgp pump activity with PSC833 in leukemic blast samples with the highest mean Pgp expression. Subpopulations of blast calls with higher Pgp activity are likely to be present. Their relevance has to be studied further. The methods outlined here allow the reliable, quantitative monitoring of the Pgp/MDR1 phenotype in leukemias in multicentered, clinical Pgp modulation studies.

Dipyridamole is known as a potent inhibitor of facilitated diffusion-mediated nucleoside transport as well as a modulator of ‘classical' multidrug resistance. BIBW22BS, a derivative of dipyridamole, has been found to be 20-to 100-fold more potent in the reversal of multidrug resistance when compared to the parent compound. In parallel, we studied the efficacy of BIBW22BS in the modulation of the antiproliferative effects of 5-fluorouracil, methotrexate and gemcitabine in human cancer cell lines. BIBW22BS, at non-toxic concentrations up to 1.0 μM, increased the antiproliferative effects of 5-fluorouracil 2- to 6-fold in seven of the eight colon cancer cell lines tested in a dose-dependent manner. The addition of 1.0 μM BIBW22BS to methotrexate resulted in a slight increase in the antiproliferative effects, but inhibited the activity of gemcitabine 30- to 100-fold in various cancer cell lines. In vitro , no notable difference was found between BIBW22BS and dipyridamole in their capacity to modulate the activity of the antimetabolites studied. BIBW22BS did not affect the growth inhibition induced by 5-fluorouracil or gemcitabine in human tumour xenografts grown subcutaneously in nude mice. We confirmed the higher potency of BIBW22BS when compared to dipyridamole in the reversal of drug resistance in the Pgppositive COLO 320 cell line.

In this study we report that the multidrug resistance protein (MRP) transports calcein from the cytoplasmic compartment of tumor cells, in contrast to P-glycoprotein which transports calcein acetoxymethyl ester from the plasmamembrane. The transport of calcein by MRP is ATP-dependent and is inhibited by probenecid and vincristine. Intracellular glutathione (GSH) depletion which occurred when cells were exposed to buthionine sulfoximine had no effect on the efflux of calcein, whereas it reversed the daunorubicin accumulation deficit in MRP overexpressing tumor cells. In conclusion, ATP-dependent transport of calcein and possibly other organic anions by MRP is not inhibited by a large decrease of the intracellular GSH concentration, that inhibits daunorubicin efflux by MRP.

The physiology of the multidrug transporter P-glycoprotein (Pgp) is still poorly understood. We now show evidence that cell lines with a high expression of Pgp display a reduced accumulation of cortisol and an ATP-dependent outward transport of the hormone. Cortisol efflux from Pgp negative cells does not have such an active component. Further we show that the steroid hormones cortisol, testosterone, and progesterone cause an immediate, dose-dependent increase of daunorubicin accumulation in Pgp overexpressing cells. These effects are particularly apparent for the more lipophilic steroids. These results demonstrate that Pgp may function as a transporter for cortisol and suggest a physiological role of the protein in steroid handling by organs such as the adrenal.