Kinase Mutations and Imatinib Response in Patients With Metastatic Gastrointestinal Stromal Tumor

PURPOSE

Most gastrointestinal stromal tumors (GISTs) express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. The relationship between mutations in these kinases and clinical response to imatinib was examined in a group of patients with advanced GIST.

PATIENTS AND METHODS

GISTs from 127 patients enrolled onto a phase II clinical study of imatinib were examined for mutations of KIT or PDGFRA. Mutation types were correlated with clinical outcome.

RESULTS

Activating mutations of KIT or PDGFRA were found in 112 (88.2%) and six (4.7%) GISTs, respectively. Most KIT mutations involved exon 9 (n = 23) or exon 11 (n = 85). All KIT mutant isoforms, but only a subset of PDGFRA mutant isoforms, were sensitive to imatinib, in vitro. In patients with GISTs harboring exon 11 KIT mutations, the partial response rate (PR) was 83.5%, whereas patients with tumors containing an exon 9 KIT mutation or no detectable mutation of KIT or PDGFRA had PR rates of 47.8% (P = .0006) and 0.0% (P < .0001), respectively. Patients whose tumors contained exon 11 KIT mutations had a longer event-free and overall survival than those whose tumors expressed either exon 9 KIT mutations or had no detectable kinase mutation.

CONCLUSION

Activating mutations of KIT or PDGFRA are found in the vast majority of GISTs, and the mutational status of these oncoproteins is predictive of clinical response to imatinib. PDGFRA mutations can explain response and sensitivity to imatinib in some GISTs lacking KIT mutations.

The impacts of a global pandemic on the efficacy and stability of contemporary wildlife conservation: South Africa as a case study

Conservationists speculated on potential benefits to wildlife of lockdown restrictions because of the COVID-19 pandemic but voiced concern that restrictions impeded nature conservation. We assessed the effects of lockdown restrictions on biodiversity conservation in South Africa, a biodiverse country with economic inequality and reliance on wildlife resources. We solicited expert opinion using the IUCN's Threats Classification Scheme to structure a questionnaire and illustrated responses with individual case studies from government parastatal and non-governmental conservation organisations. The most highly reported threats were biological resource use, residential/commercial developments, invasive species, and human intrusions. The trends reported by 90 survey respondents were supported by case studies using environmental compliance data from parastatal conservation organisations. Lack of tourism revenue and funding were cited as hindrances to conservation. Mechanisms to prevent environmental degradation in the face of global emergencies must be implemented and 'ring-fenced' to ensure conservation is not a casualty during future global crises.

Correction to: Uncemented Thompson's hemiarthroplasty: safe, palliative and cost-effective surgery in the infirm patient-a consecutive series of 1445 cases

The original version of this article unfortunately contained a mistake. David Morley was not listed among the authors.

Myelopreservation with the CDK4/6 inhibitor trilaciclib in patients with small-cell lung cancer receiving first-line chemotherapy: a phase Ib/randomized phase II trial

BACKGROUND

Chemotherapy-induced damage of hematopoietic stem and progenitor cells (HSPC) causes multi-lineage myelosuppression. Trilaciclib is an intravenous CDK4/6 inhibitor in development to proactively preserve HSPC and immune system function during chemotherapy (myelopreservation). Preclinically, trilaciclib transiently maintains HSPC in G1 arrest and protects them from chemotherapy damage, leading to faster hematopoietic recovery and enhanced antitumor immunity.

PATIENTS AND METHODS

This was a phase Ib (open-label, dose-finding) and phase II (randomized, double-blind placebo-controlled) study of the safety, efficacy and PK of trilaciclib in combination with etoposide/carboplatin (E/P) therapy for treatment-naive extensive-stage small-cell lung cancer patients. Patients received trilaciclib or placebo before E/P on days 1-3 of each cycle. Select end points were prespecified to assess the effect of trilaciclib on myelosuppression and antitumor efficacy.

RESULTS

A total of 122 patients were enrolled, with 19 patients in part 1 and 75 patients in part 2 receiving study drug. Improvements were seen with trilaciclib in neutrophil, RBC (red blood cell) and lymphocyte measures. Safety on trilaciclib+E/P was improved with fewer ≥G3 adverse events (AEs) in trilaciclib (50%) versus placebo (83.8%), primarily due to less hematological toxicity. No trilaciclib-related ≥G3 AEs occurred. Antitumor efficacy assessment for trilaciclib versus placebo, respectively, showed: ORR (66.7% versus 56.8%, P = 0.3831); median PFS [6.2 versus 5.0 m; hazard ratio (HR) 0.71; P = 0.1695]; and OS (10.9 versus 10.6 m; HR 0.87; P = 0.6107).

CONCLUSION

Trilaciclib demonstrated an improvement in the patient's tolerability of chemotherapy as shown by myelopreservation across multiple hematopoietic lineages resulting in fewer supportive care interventions and dose reductions, improved safety profile, and no detriment to antitumor efficacy. These data demonstrate strong proof-of-concept for trilaciclib's myelopreservation benefits.

CLINICAL TRAIL NUMBER

NCT02499770.

Abstract PD1-01: Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results

Background: Cytotoxic chemotherapy-induced damage of hematopoietic stem and progenitor cells (HSPCs) results in acute toxicities consisting of multi-lineage myelosuppression, and late onset toxicities consisting of progressive bone marrow suppression with increased incidence of therapy-related myeloid neoplasms. T is an IV CDK4/6 inhibitor in development to preserve HSPC and immune system function during cytotoxic chemotherapy (myelopreservation). Proof of concept for myelopreservation with T was observed in a randomized, placebo-controlled Phase 2 trial in small-cell lung cancer patients receiving 1st-line chemotherapy. This trial in mTNBC patients (NCT02978716) was designed to explore the utility of T in combination with GC.

Methods: This Phase 2, randomized, open-label study enrolled patients in the US and EU with mTNBC who had received 0-2 prior systemic cytotoxic therapies in the locally recurrent or metastatic setting and had no symptomatic brain metastases. Patients were randomized (1:1:1) to GC alone (Group 1) or T plus GC (Group 2) using a standard schedule (D1, 8 every 21 days) or to an alternative schedule (T on D1, 2, 8 and 9 with GC on D2 and 9 every 21 days; Group 3). On those days when both T and GC were scheduled, T was administered iv prior to GC infusion. Prophylactic growth factors were not administered in cycle 1; otherwise supportive care was allowed as needed. Primary objectives were safety and tolerability; tumor response was evaluated using RECIST v1.1 and PFS and OS were assessed. Myelopreservation endpoints reflecting the potential effects of T on multiple cellular lineages include occurrence of Grade 4 neutropenia (primary), RBC and platelet transfusions (primary), and lymphocyte counts with immune profiling (secondary and exploratory). A signature of CDK4/6 independence developed from preclinical data will be used to evaluate archival tumor tissue samples and data analysis is ongoing.

Results: 95 patients were dosed; median age 57 years (range 32,86), ECOG PS 0 (53%) or 1 (47%), 25% had liver metastases at baseline, and approximately 50% had received no systemic therapy in the recurrent/metastatic setting. Fifty-five patients remain on treatment. Disease progression was the most common reason for drug discontinuation (22/40; 55%). Overall the most common (≥ 25%) TEAEs were anemia (47%), nausea (35%), fatigue (34%), neutropenia (32%), platelet count decreased (25%), and vomiting (25%). The most frequent (≥ 15%) Grade 3 or 4 TEAEs were hematologic toxicities, i.e. neutropenia (28%), anemia (21%), neutrophil count decreased (21%) and thrombocytopenia (16%). These were also the most frequent drug-related TEAEs observed. Tumor efficacy data are being evaluated.

Conclusions: This trial, assessing the myelopreservation effects of T when combined with GC in patients with mTNBC, has completed enrollment. Myelopreservation data, immune profiling, as well as ORR and preliminary PFS results will be presented by study arm at the meeting.

Citation Format: O'Shaughnessy J, Wright GS, Thummala AR, Danso MA, Popovic L, Pluard TJ, Cheung E, Han HS, Daniel BR, Vojnovic Z, Vasev N, Ling M, Richards DA, Wilks ST, Milenkovic D, Sorrentino JA, Roberts PJ, Bomar M, Yang Z, Antal JM, Malik RK, Morris SR, Tan A. Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-01.

Uncemented Thompson's hemiarthroplasty: safe, palliative and cost-effective surgery in the infirm patient-a consecutive series of 1445 cases

BACKGROUND

Guidelines on the management of displaced intracapsular fractures recommend using an Orthopaedic Data Evaluation Panel-rated cemented implant. Prior to the National Institute for Health and Care Excellence guidelines, uncemented implants were commonly used in the UK.

METHODS

We retrospectively examined the outcomes of patients with uncemented Thompson's hemiarthroplasties at our unit, between April 2005 and December 2010. Patients who underwent revision surgery before December 2011 were identified. Implant survival calculation utilised the primary outcome of revision to total hip arthroplasty, revision hemiarthroplasty or excision arthroplasty. Patients who died post-operatively were identified and censored.

RESULTS

A total of 1445 patients received uncemented Thompson's implant. Patient mean age was 82 years with 76% female. Forty-six (3.2%) patients required revision with 15% performed within 30 days of surgery and 62% within 1 year. Reasons for revision were infection (0.83%), acetabular erosion (0.83%) and loosening (0.62%). Twenty-seven patients (59% of total revisions) underwent revision to THA, 14 (30%) to excision arthroplasty and 5 (11%) to revision hemiarthroplasty. Cumulative survival rate was 98% at 1 year and 95% at 5 years. Thirty-day mortality was 7.1%. One-year mortality was 28.1%.

CONCLUSION

Current guidelines strongly favour cemented hemiarthroplasty. Recognition that fractured hip patients are a non-homogeneous group is important. In patients with limited life expectancy, an uncemented Thompson is a quick, simple, palliative solution to early mobilisation. Correct surgical technique avoids using cement in this cohort, which is most vulnerable to bone cement implantation syndrome. Cost-effective resource utilisation with an increasingly elderly population remains a surgical responsibility.

Quality of life following laparoscopic Nissen fundoplication: Assessing short-term and long-term outcomes

AIM: To investigate the quality of life following laparoscopic Nissen fundoplication by assessing short-term and long-term outcomes.

METHODS: From 1992 to 2005, 249 patients underwent laparoscopic Nissen fundoplication. Short-term outcome data including symptom response, side effects of surgery, endoscopy, and patient’s perception of overall success were collected prospectively. Long-term outcomes were investigated retrospectively in patients with a median follow-up of 10 years by assessment of reflux symptoms, side effects of surgery, durability of antireflux surgery, need for additional treatment, patient’s perception of success, and quality of life. Antireflux surgery was considered a failure based on the following criteria: moderate to severe heartburn or regurgitation; moderate to severe dysphagia reported in combination with heartburn or regurgitation; regular proton pump inhibitor medication use; endoscopic evidence of erosive esophagitis Savary-Miller grade 1-4; pathological 24-h pH monitoring; or necessity to undergo an additional surgery. The main outcome measures were short- and long-term cure rates and quality of life, with patient satisfaction as a secondary outcome measure.

RESULTS: Conversion from laparoscopy to open surgery was necessary in 2.4% of patients. Mortality was zero and the 30-d morbidity was 7.6% (95%CI: 4.7%-11.7%). The median postoperative hospital stay was 2 d [interquartile range (IQR) 2-3 d]. Two hundred and forty-seven patients were interviewed for short-term analysis following endoscopy. Gastroesophageal reflux disease was cured in 98.4% (95%CI: 95.9%-99.6%) of patients three months after surgery. New-onset dysphagia was encountered postoperatively in 13 patients (6.7%); 95% reported that the outcome was better after antireflux surgery than with preoperative medical treatment. One hundred and thirty-nine patients with a median follow-up of 10.2 years (IQR 7.2-11.6 years) were available for a long-term evaluation. Cumulative long-term cure rates were 87.7% (81.0%-92.2%) at 5 years and 72.9% (64.0%-79.9%) at 10 years. Gastrointestinal symptom rating scores and RAND-36 quality of life scores of patients with treatment success were similar to those of the general population but significantly lower in those with failed antireflux surgery. Of the patients available for long-term follow-up, 83% rated their operation a success.

CONCLUSION: For the long-term, our results indicate decreasing effectiveness of laparoscopic antireflux surgery, although most of the patients seem to have an overall quality of life similar to that of the general population.

MMP-1 expression has an independent prognostic value in breast cancer

Background

Breast cancer consists of a variety of tumours, which differ by their morphological features, molecular characteristics and outcome. Well-known prognostic factors, e.g. tumour grade and size, Ki-67, hormone receptor status, HER2 expression, lymph node status and patient age have been traditionally related to prognosis. Although the conventional prognostic markers are reliable in general, better markers to predict the outcome of an individual tumour are needed.

Matrix metalloproteinase-1 (MMP-1) expression has been reported to inversely correlate with survival in advanced cancers. In breast cancer MMP-1 is often upregulated, especially in basal-type breast tumours. The purpose of this retrospective study was to analyse MMP-1 expression in breast cancer cells and in cancer associated stromal cells and to correlate the results with traditional prognostic factors including p53 and bcl-2, as well as to patient survival in breast cancer subtypes.

Methods

Immunohistochemical analysis of MMP-1, ER, PR, Ki-67, HER2, bcl-2, p53 and CK5/6 expression was performed on 125 breast cancers. Statistical analyses were carried out using Kruskal-Wallis and Mann-Whitney -tests. In pairwise comparison Bonferroni-adjustment was applied. Correlations were calculated using Spearman rank-order correlation coefficients. Kaplan-Meier survival analyses were carried out to compare breast cancer-specific survival curves. Factors significantly associated with disease-specific survival in univariate models were included in multivariate stepwise.

Results

Positive correlations were found between tumour grade and MMP-1 expression in tumour cells and in stromal cells. P53 positivity significantly correlated with MMP-1 expression in tumour cells, whereas HER2 expression correlated with MMP-1 both in tumour cells and stromal cells. MMP-1 expression in stromal cells showed a significant association with luminal A and luminal B, HER2 overexpressing and triple-negative breast cancer subtypes.

Conclusions

The most important finding of this study was the independent prognostic value of MMP-1 as well as Ki-67 and bcl-2 expression in tumour cells. Our study showed also that both tumoural and stromal MMP-1 expression is associated with breast tumour progression and poor prognosis. A significant difference of MMP-1 expression by cancer associated stromal cells in luminal A, luminal B and triple-negative breast cancer classes was also demonstrated.

Please see related commentary article http://www.biomedcentral.com/1741-7015/9/95

Low loss broadband transmission in hypocycloid-core Kagome hollow-core photonic crystal fiber

We report on the fabrication of a seven-cell-core and three-ring-cladding large-pitch Kagome-lattice hollow-core photonic crystal fiber (HC-PCF) with a hypocycloid-shaped core structure. We demonstrate experimentally and theoretically that the design of this core shape enhances the coupling inhibition between the core and cladding modes and offers optical attenuation with a baseline of ∼180 dB/km over a transmission bandwidth larger than 200 THz. This loss figure rivals the state-of-the-art photonic bandgap HC-PCF while offering an approximately three times larger bandwidth and larger mode areas. Also, it beats the conventional circular-core-shaped Kagome HC-PCF in terms of the loss. The development of this novel (to our knowledge) HC-PCF has potential for a number of applications in which the combination of a large optical bandwidth and a low loss is a prerequisite.

Metabotropic glutamate receptor mGlu2 is resistant to homologous agonist-induced desensitization but undergoes protein kinase C-mediated heterologous desensitization

To investigate the susceptibility of the group II metabotropic glutamate receptor mGlu2 to agonist-induced desensitization, the receptor was stably expressed in Chinese hamster ovary (CHO-mGlu2) or C6 glioma cells (C6-mGlu2). Exposure of CHO-mGlu2 cells to the group II mGlu receptor agonist (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (LCCG-1; 10 μM) for up to 15 h did not affect the subsequent ability of LCCG-1 to inhibit forskolin-stimulated cAMP accumulation. Similarly, in C6-mGlu2 cells, prolonged exposure to LCCG-1 also did not affect the subsequent ability of LCCG-1 to inhibit cAMP formation. In contrast, exposure of CHO-mGlu2 cells to the protein kinase C activator phorbol myristate acetate (PMA) suppressed the ability of LCCG-1 to inhibit cAMP formation. Using an in vitro model of group II mGlu receptor activity, the hemisected neonatal rat spinal cord preparation, the ability of the selective group II agonist (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate ((2R,4R)-APDC) to depress the fast component of the dorsal root-evoked ventral root potential (fDR-VRP) did not desensitize when applied for up to 2 h. Together these results indicate that in contrast to most G protein-coupled receptors, the mGlu2 receptor is resistant to agonist-induced homologous desensitization, and that in vitro data suggests that resistance to desensitization is a physiologically relevant property of this mGlu receptor subtype.

Stress induced birefringence in hybrid TIR/PBG guiding solid photonic crystal fibers

We report on two types of polarization maintaining solid photonic crystal fibers that guide light by a combination of a photonic bandgap and total internal reflection. Group and phase birefringence are studied experimentally and numerically for stress-applying parts made from B-doped and F-doped silica. The stress field originating from Ge-doped cladding rods is shown to interfere with the stress field from the B-doped and F-doped rods. Since the differential expansion coefficients of B-doped and F-doped silica have opposite signs this interference is either destructive or constructive. Consequently, we found that the fiber with F-doped stress applying parts has the highest modal phase birefringence, and polarization cross talk is characterized by an h-parameter below 310(-5) m(-1).

7-cell core hollow-core photonic crystal fibers with low loss in the spectral region around 2 microm

Several 7 cell core hollow-core photonic crystal fibers with bandgaps in the spectral range of 1.4 microm to 2.3 microm have been fabricated. The transmission loss follows the approximately lambda(-3) dependency previously reported, with a minimum measured loss of 9.5 dB/km at 1.99 microm. One fiber with a transmission loss of 26 dB/km at 2.3 microm is reported, which is significantly lower than the transmission loss of solid silica fibers at this wavelength.

Square-lattice large-pitch hollow-core photonic crystal fiber

We report on the design, fabrication and characterization of silica square-lattice hollow core photonic crystal fibers optimized for low loss guidance over an extended frequency range in the mid-IR region of the optical spectrum. The fiber's linear optical properties include an ultra-low group velocity dispersion and a polarization cross-coupling as low as -13.4 dB over 10 m of fiber.

Fourth-order dispersion mediated solitonic radiations in HC-PCF cladding

We observe experimentally, for the first time to our knowledge, the simultaneous emission of two strong conjugate resonant dispersive waves by optical solitons. The effect is observed in a small waveguiding glass feature within the cladding of a Kagome hollow-core photonic crystal fiber. We demonstrate theoretically that the phenomenon is attributed to the unusually high fourth-order dispersion coefficient of the waveguiding feature.

Nonlinear interaction between two different photonic bandgaps of a hybrid photonic crystal fiber

Nonlinear interaction between spectral components in two different photonic bandgaps is experimentally demonstrated by launching femtosecond pulses near a zero-dispersion wavelength of a hybrid photonic crystal fiber, which guides by a combination of total internal reflection and bandgap effects. It is demonstrated that the initial pulse becomes spectrally broadened, and narrowband resonant radiation is generated in a different bandgap from the one responsible for guiding at the pump wavelength. The spectral intensity of the resonant radiation peaks at 2.7 dB below that of the broadened pulse in the pump-guiding bandgap.

Dispersive pulse compression in hollow-core photonic bandgap fibers

Compression of linearly chirped picosecond pulses in hollow-core photonic bandgap fibers is investigated numerically. The modal properties of the fibers are modeled using the finite-element technique, whereas nonlinear propagation is described by a generalized nonlinear Schrödinger equation, which accounts both for the composite nature of the nonlinearity and the strong mode profile dispersion. Power limits for compression with more than 90% of the pulse energy in the main peak of the compressed pulse are investigated as a function of fiber design, and the temporal and spectral widths of the input pulse. The validity of approximate scaling rules is investigated, and figures of merit for fiber design are discussed.

Long-term results from a randomized phase II trial of standard- versus higher-dose imatinib mesylate for patients with unresectable or metastatic gastrointestinal stromal tumors expressing KIT

PURPOSE

The outcome of patients diagnosed with advanced gastrointestinal stromal tumor (GIST) and treated long-term with imatinib mesylate is unknown. A previous report of a randomized phase II trial of imatinib mesylate in patients with incurable GIST detailed high response rates at both the 400 and the 600 mg/d dose levels. We conducted a long-term analysis of patients treated on the trial, including patients followed during an extension phase, to evaluate survival, patterns of failure, and potential prognostic factors, including tumor mutational status.

PATIENTS AND METHODS

Patients with advanced GIST were enrolled onto an open-label, multicenter trial and were randomly assigned (1:1) to receive imatinib 400 versus 600 mg/d. Data were prospectively collected on KIT mutational status, total tumor area, and other potential prognostic factors. Patients were followed for a median of 63 months.

RESULTS

One hundred forty-seven patients were enrolled: 73 were in arm A (imatinib 400 mg/d), and 74 were in arm B (imatinib 600 mg/d). Response rates, median progression-free survival, and median overall survival were essentially identical on both arms, and median survival was 57 months for all patients. Forty-one patients overall (28%) remained on the drug long-term. Female sex, the presence of an exon 11 mutation, and normal albumin and neutrophil levels were independently associated with better survival.

CONCLUSION

Nearly 50% of patients with advanced GIST who were treated with imatinib mesylate survived for more than 5 years, regardless of a 400 or 600 mg/d starting dose.

Prognostic significance of matrix metalloproteinases-1, -2, -7 and -13 and tissue inhibitors of metalloproteinases-1, -2, -3 and -4 in colorectal cancer

Strong expression of many matrix metalloproteinases (MMPs) has been related to poor survival of colorectal cancer (CRC) patients. The expression of tissue inhibitors of metalloproteinases (TIMPs) has been associated with both a beneficial and a poor outcome and there is thus a need to further clarify the significance of MMPs and TIMPs in CRC. The prognostic significance of 4 MMPs and TIMPs in CRC was evaluated. Formalin-fixed, paraffin-embedded tissue arrayed samples of 351 patients with primary colon or rectal cancer of Dukes' stages A-D were selected for immunohistochemical staining of MMP-1, -2, -7 and -13, and TIMP-1, -2, -3 and -4. High expression of MMP-2 in the malignant epithelium as well as in the surrounding stroma was associated with reduced survival of colon cancer patients. Strong epithelial and stromal cytoplasmic staining of TIMP-3 was associated with a longer survival in rectal cancer patients, and here the interobserver variation for evaluating the degree of staining was lower than for epithelial staining. Strong stromal cytoplasmic staining of TIMP-4 predicted longer survival of rectal cancer patients. Multivariate analysis showed that stromal cytoplasmic TIMP-3 staining was the only marker of independent prognostic value. MMP-2 might be a useful prognostic marker in colon cancer, and TIMP-3 and TIMP-4 in rectal cancer, but the findings associated with stromal staining should be interpreted with some caution. Different biologic behavior or different genetic development may explain the differences between colon and rectal cancers regarding the expression of MMP-2, TIMP-3 and TIMP-4.

Targeting the Raf-MEK-ERK mitogen-activated protein kinase cascade for the treatment of cancer

Mitogen-activated protein kinase (MAPK) cascades are key signaling pathways involved in the regulation of normal cell proliferation, survival and differentiation. Aberrant regulation of MAPK cascades contribute to cancer and other human diseases. In particular, the extracellular signal-regulated kinase (ERK) MAPK pathway has been the subject of intense research scrutiny leading to the development of pharmacologic inhibitors for the treatment of cancer. ERK is a downstream component of an evolutionarily conserved signaling module that is activated by the Raf serine/threonine kinases. Raf activates the MAPK/ERK kinase (MEK)1/2 dual-specificity protein kinases, which then activate ERK1/2. The mutational activation of Raf in human cancers supports the important role of this pathway in human oncogenesis. Additionally, the Raf-MEK-ERK pathway is a key downstream effector of the Ras small GTPase, the most frequently mutated oncogene in human cancers. Finally, Ras is a key downstream effector of the epidermal growth factor receptor (EGFR), which is mutationally activated and/or overexpressed in a wide variety of human cancers. ERK activation also promotes upregulated expression of EGFR ligands, promoting an autocrine growth loop critical for tumor growth. Thus, the EGFR-Ras-Raf-MEK-ERK signaling network has been the subject of intense research and pharmaceutical scrutiny to identify novel target-based approaches for cancer treatment. In this review, we summarize the current status of the different approaches and targets that are under evaluation and development for the therapeutic intervention of this key signaling pathway in human disease.

Mechanisms of glutamate receptor induced proliferation of astrocytes

Astrocytes express mainly metabotropic glutamate receptor 3 and metabotropic glutamate receptor 5 receptor subtypes, which show opposing effects on cellular proliferation upon activation. In this study, we investigated the mechanisms by which activation of these receptors modulates astrocyte proliferation. Activation of metabotropic glutamate receptor 5 with (S)-3,5-dihydroxyphenylglycine increased phospholipase D activity in astrocytes as well as astrocyte proliferation. The 3,5-dihydroxyphenylglycine-induced proliferation was inhibited in the presence of the metabotropic glutamate receptor 5 antagonist (2-methyl-6-(phenylethynyl)pyridine), the protein kinase C inhibitor GF109203X, brefeldin A and 1-butanol. Activation of metabotropic glutamate receptor 3 with (2'S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine-IV (DCG-IV) inhibited astrocyte proliferation without affecting metabotropic glutamate receptor 5-mediated phospholipase D activity. Metabotropic glutamate receptor 3 activation, however, only partially inhibited metabotropic glutamate receptor 5-mediated proliferation. In conclusion, metabotropic glutamate receptor 5 stimulates astrocyte proliferation via a protein kinase C-phospholipase D-phosphatidic acid-dependent pathway, whereas metabotropic glutamate receptor 3-mediated inhibition of astrocyte proliferation does not involve phospholipase D, and is independent of metabotropic glutamate receptor 5-mediated effects.

Identification of Bloch-modes in hollow-core photonic crystal fiber cladding

We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field nformation is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives the propagation is found to be spatially coherent and to contain contributions from just a few types of cladding mode.

Molecular Correlates of Imatinib Resistance in Gastrointestinal Stromal Tumors

Purpose

Gastrointestinal stromal tumors (GISTs) commonly harbor oncogenic mutations of the KIT or platelet-derived growth factor alpha (PDGFRA) kinases, which are targets for imatinib. In clinical studies, 75% to 90% of patients with advanced GISTs experience clinical benefit from imatinib. However, imatinib resistance is an increasing clinical problem.

Patients and Methods

One hundred forty-seven patients with advanced, unresectable GISTs were enrolled onto a randomized, phase II clinical study of imatinib. Specimens from pretreatment and/or imatinib-resistant tumors were analyzed to identify molecular correlates of imatinib resistance. Secondary kinase mutations of KIT or PDGFRA that were identified in imatinib-resistant GISTs were biochemically profiled for imatinib sensitivity.

Results

Molecular studies were performed using specimens from 10 patients with primary and 33 patients with secondary resistance. Imatinib-resistant tumors had levels of activated KIT that were similar to or greater than those typically found in untreated GISTs. Secondary kinase mutations were rare in GISTs with primary resistance but frequently found in GISTs with secondary resistance (10% v 67%; P = .002). Evidence for clonal evolution and/or polyclonal secondary kinase mutations was seen in three (18.8%) of 16 patients. Secondary kinase mutations were nonrandomly distributed and were associated with decreased imatinib sensitivity compared with typical KIT exon 11 mutations. Using RNAi technology, we demonstrated that imatinib-resistant GIST cells remain dependent on KIT kinase activity for activation of critical downstream signaling pathways.

Conclusion

Different molecular mechanisms are responsible for primary and secondary imatinib resistance in GISTs. These findings have implications for future approaches to the growing problem of imatinib resistance in patients with advanced GISTs.

Design of low-loss and highly birefringent hollow-core photonic crystal fiber

A practical hollow-core photonic crystal fiber design suitable for attaining low-loss propagation is analyzed. The geometry involves a number of localized elliptical features positioned on the glass ring that surrounds the air core and separates the core and cladding regions. The size of each feature is tuned so that the composite core-surround geometry is antiresonant within the cladding band gap, thus minimizing the guided mode field intensity both within the fiber material and at material/air interfaces. A birefringent design, which involves a 2-fold symmetric arrangement of the features on the core-surround ring, gives rise to wavelength ranges where the effective index difference between the polarization modes is larger than 10(-4). At such high birefringence levels, one of the polarization modes retains favorable field exclusion characteristics, thus enabling low-loss propagation of this polarization channel.

Analysis of mGluR1a constitutive internalization using a pulse-chase enzyme-linked immuno-sorbant assay (ELISA)

The surface expression of G protein-coupled receptors is regulated by internalization. For many receptors, a constitutive level of internalization in the absence of agonist has been reported. The constitutive internalization of metabotropic glutamate receptor 1a (mGluR1a) has been described, but in general little attention has been dedicated to this important aspect of receptor regulation. Here we describe a pulse-chase ELISA method that allows the investigation of mGluR1a constitutive internalization. When investigated by pulse-chase ELISA, the constitutive internalization of mGluR1a was inhibited by dominant negative mutant constructs of arrestin-2 or Eps-15. This observation, besides indicating the arrestin- and clathrin-dependence of mGluR1a constitutive internalization, also confirmed the physiological relevance of the method described in this article. Confocal microscopy experiments to study receptor localization further validated the pulse-chase labelling procedure. The application of the pulse-chase ELISA to mGluR1b, revealed that this splice variant undergoes marginal constitutive internalization. Two COOH-terminal deletion mutants of mGluR1a, DMI (Arg847stop) and DMII (Arg868stop), were also tested for constitutive internalization. Interestingly, only DMII underwent significant constitutive internalization, suggesting that the region between Arg847 and Arg868 might play a regulatory role in mGluR1a trafficking. Taken together, the pulse-chase ELISA appears to be an efficient tool to analyze the constitutive internalization of different mGluR1 splice variants.

The significance of tumor markers for proliferation and apoptosis in predicting survival in colorectal cancer

PURPOSE

Clinicopathologic staging is even today the best prognostic factor in both colon and rectal cancers. There is still considerable variation in survival within the stages. To find other prognostic indicators we investigated six biologic markers associated with apoptosis and cell proliferation.

METHODS

Formalin-fixed, paraffin-embedded tissue samples of 363 patients with primary colon or rectal cancer of Dukes Stages A to D were chosen for immunohistochemical staining of five tumor markers: bcl-2, p53, Ki-67, cyclin D1, and carcinoembryonic antigen. Also, the number of apoptotic cells was studied by the terminal deoxynucleotidyl transferase-mediated D: -UTP nick end labeling method in 347 cases. The study was done on specially prepared tissue arrays.

RESULTS

In rectal cancer, patients with a Ki-67 labeling index of 5 percent or higher had a better prognosis than those with a lower index. Also, positive cytoplasmic p53 expression predicted a favorable outcome in rectal cancer. In colon cancer, positive nuclear staining of cyclin D1 reflected better survival. Weak and moderate staining of carcinoembryonic antigen correlated with better prognosis than strong staining, but negative staining predicted poor outcome. High apoptotic index of 100 or higher correlated with poor prognosis in colon cancer. However, in rectal cancer, the trend was the opposite. Bcl-2 staining tended to be more intense in samples of patients living 5 years or longer compared with those with worse prognosis.

CONCLUSIONS

Colon cancer and rectal cancer seem to have different biologic behavior, at least with respect to apoptosis, cytoplasmic p53 expression, and perhaps Ki-67 and carcinoembryonic antigen. Further studies are needed to clarify the significance of these factors.

Synthesis and Pharmacology of Willardiine Derivatives Acting as Antagonists of Kainate Receptors

The natural product willardiine (8) is an AMPA receptor agonist while 5-iodowillardiine (10) is a selective kainate receptor agonist. In an attempt to produce antagonists of kainate and AMPA receptors analogues of willardiine with substituents at the N3 position of the uracil ring were synthesized. The N3-4-carboxybenzyl substituted analogue (38c) was found to be equipotent at AMPA and GLUK5-containing kainate receptors in the neonatal rat spinal cord. The N3-2-carboxybenzyl substituted analogue (38a) proved to be a potent and selective GLUK5 subunit containing kainate receptor antagonist when tested on native rat and human recombinant AMPA and kainate receptor subtypes. The GLUK5 kainate receptor antagonist activity was found to reside in the S enantiomer (44a) whereas the R enantiomer (44b) was almost inactive. 5-Iodo substitution of the uracil ring of 44a gave 45, which was found to have enhanced potency and selectivity for GLUK5.

Selective mode excitation in hollow-core photonic crystal fiber

Modes are selectively excited by launching light through the cladding from the side into a hollow-core photonic crystal fiber. Measuring the total output power at the end of the fiber as a function of the angle of incidence of the exciting laser beam provides a powerful diagnostic for characterizing the cladding bandgap. Furthermore, various types of modes on either side of the bandgap are excited individually, and their near-field images are obtained.

The influence of training level and surgical experience on survival in colorectal cancer

BACKGROUND AND AIMS

The effect of surgical training level, experience, and operation volume on complications and survival in colorectal cancer during a 10-year period in a medium-volume university hospital was retrospectively studied.

PATIENTS AND METHODS

Four hundred and fifty-six patients were resected for primary colorectal adenocarcinoma during the 10-year period of 1981-1990, and of these, 387 patients underwent resection with curative intent. The surgeons were divided into three groups according to training level and volume: group 1, surgeons in training and other surgeons operating annually on only 1-4 patients; group 2, surgeons specializing in gastrointestinal surgery (average annual volume 4-13 operations); group 3, specialists in gastrointestinal surgery (average annual volume 3-8 operations). Postoperative morbidity and mortality rates, as well as long-term survival rates, were analysed, and comparisons were made between the patients in the three groups.

RESULTS

There were no statistically significant differences between the three groups in postoperative morbidity or mortality. Cancer-specific 5-year survival rate of all patients was 57%, and that of those resected in the aforementioned three groups was 51%, 63%, and 55%, respectively, P=0.087. The 5-year survival rates for colon cancer were 59% (total), 52%, 69%, and 58%, respectively, P=0.067, and for rectal cancer were 51% (total), 42%, 53%, and 52%, respectively, P=0.585.

CONCLUSION

There were no significant differences in the rates of postoperative mortality, morbidity, and long-term overall survival between the volume groups. However, in patients with colon cancer, there was a trend for better survival for those operated on by the surgeons specializing in gastrointestinal surgery, and in rectal cancer patients, a tendency of fewer local recurrences in those operated on by the specialist surgeons.

Desensitization and internalization of metabotropic glutamate receptor 1a following activation of heterologous Gq/11-coupled receptors

In this study we characterized the heterologous desensitization and internalization of the metabotropic glutamate receptor 1 (mGluR1) splice variants mGluR1a and mGluR1b following activation of endogenous G(q/11)-coupled receptors in HEK293 cells. Agonist activation of M1 muscarinic acetylcholine or P2Y1 purinergic receptors triggered the PKC- and CaMKII-dependent internalization of mGluR1a. In co-immunoprecipitation studies, both glutamate and carbachol increased the association of GRK2 with mGluR1a. Co-addition of the protein kinase C (PKC) inhibitor GF109203X and the Ca(2+) calmodulin-dependent kinase II (CaMKII) inhibitor KN-93 blocked the ability of glutamate and carbachol to increase the association of GRK2 with mGluR1a. Glutamate also increased the association of GRK2 with mGluR1b, whereas carbachol did not. However, unlike mGluR1a, glutamate-stimulated association of GRK2 with mGluR1b was not reduced by PKC/CaMKII inhibition. Pretreatment of cells expressing mGluR1a or mGluR1b with carbachol rapidly desensitized subsequent glutamate-stimulated inositol phosphate accumulation. The carbachol-induced heterologous desensitization and internalization of mGluR1a was blocked by LY367385, an mGluR1a antagonist with inverse agonist activity. Furthermore, LY367385 blocked the ability of carbachol to increase the association of GRK2 with mGluR1a. On the other hand, LY367385 had no effect on the carbachol-induced desensitization and internalization of the nonconstitutively active mGluR1b splice variant. These results demonstrate that the internalization of mGluR1a, triggered homologously by glutamate or heterologously by carbachol, is PKC/CaMKII-, GRK2-, arrestin-, and clathrin-dependent and that PKC/CaMKII activation appears to be necessary for GRK2 to associate with mGluR1a. Furthermore, the heterologous desensitization of mGluR1a is dependent upon the splice variant being in an active conformation.

Agonist-independent internalization of metabotropic glutamate receptor 1a is arrestin- and clathrin-dependent and is suppressed by receptor inverse agonists

Three group I mGluR antagonists CPCCOEt, LY367385 and BAY36-7620, were analyzed for their effect on cell surface expression of metabotropic glutamate receptor 1a and 1b. All three antagonists inhibited glutamate-induced internalization of mGluR1a and mGluR1b. However, when added alone, either LY367385 or BAY36-7620 increased the cell surface expression of mGluR1a but not mGluR1b. Both LY367385 and BAY36-7620 displayed inverse agonist activity as judged by their ability to inhibit basal inositol phosphate accumulation in cells expressing the constitutively active mGluR1a. Interestingly, mGluR1a but not mGluR1b was constitutively internalized in HEK293 cells and both LY367385 and BAY36-7620 inhibited the constitutive internalization of this splice variant. Furthermore, coexpression of dominant negative mutant constructs of arrestin-2 [arrestin-2-(319-418)] or Eps15 [Eps15(E Delta 95-295)] increased cell surface expression of mGluR1a and blocked constitutive receptor internalization. In the presence of these dominant negative mutants, incubation of cells with LY367385 and BAY36-7620 produced no further increase in cell surface expression of mGluR1a. Taken together, these results suggest that the constitutive activity of mGluR1a triggers the internalization of the receptor through an arrestin- and clathrin-dependent pathway, and that inverse agonists increase the cell surface expression of mGluR1a by promoting an inactive form of mGluR1a, which does not undergo constitutive internalization.

Reliability of radiographs in defining union of internally fixed fractures

We assessed whether radiographs can predict union of internally fixed fractures, and therefore be used as end-points in studies of fracture healing. Forty-seven radiographic series of forearm, femoral and tibial fractures treated by internal fixation over a 3-year period were reviewed. All forearm fractures were treated with dynamic compression plates (DCP), and all tibial and femoral fractures with intra-medullary nails. Callus formation and fracture line filling with time were measured on each radiograph. The ability of five orthopaedic surgeons to chronologically rank the blinded radiographs and to agree on the point of union was assessed. Correlation between callus formation, fracture line filling and union was noted. The ability of surgeons to correctly rank the radiographs and to agree on the point of union was in the order of 70%. Callus formation and union progression was significant in femoral fractures (P<0.05). Fracture line filling and union progression showed significance in the forearm (P<0.01) and femoral groups (P<0.05). Taking serial radiographs to assess healing would have led to only one early intervention. Radiographs do not define union in internally fixed fractures with sufficient accuracy to enable their use as end-points of fracture healing. Studies quoting radiographic end-points should be interpreted with care.

Activation of Cyclic AMP-Dependent Protein Kinase Inhibits the Desensitization and Internalization of Metabotropic Glutamate Receptors 1a and 1b

In this study, we characterized the effects of activation of cyclic AMP-dependent protein kinase (PKA) on the internalization and functional coupling of the metabotropic glutamate receptor (mGluR1) splice variants mGluR1a and mGluR1b. Using an enzyme-linked immunosorbent assay technique to assess receptor internalization, we found that the glutamate-induced internalization of mGluR1a or mGluR1b transiently expressed in human embryonic kidney (HEK) 293 cells was inhibited by coactivation of endogenous beta2-adrenoceptors with isoprenaline or by direct activation of adenylyl cyclase with forskolin. The PKA inhibitor N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide hydrochloride (H89) blocked the effects of both isoprenaline and forskolin. The heterologous internalization of the mGluR1 splice variants triggered by carbachol was also inhibited by isoprenaline and forskolin in a PKA-sensitive fashion, whereas the constitutive (agonist-independent) internalization of mGluR1a was inhibited only modestly by PKA activation. Using inositol phosphate (IP) accumulation in cells prelabeled with [3H]inositol to assess receptor coupling, PKA activation increased basal IP accumulation in mGluR1a receptor-expressing cells and also increased glutamate-stimulated IP accumulation in both mGluR1a- and mGluR1b-expressing cells, but only at short times of glutamate addition. Furthermore, PKA activation completely blocked the carbachol-induced heterologous desensitization of glutamate-stimulated IP accumulation in both mGluR1a- and mGluR1b-expressing cells. In coimmunoprecipitation experiments, the ability of glutamate to increase association of GRK2 and arrestin-2 with mGluR1a and mGluR1b was inhibited by PKA activation with forskolin. Together, these results indicate that PKA activation inhibits the agonist-induced internalization and desensitization of mGluR1a and mGluR1b, probably by reducing their interaction with GRK2 and nonvisual arrestins.

Does the type of flooring affect the risk of hip fracture?

BACKGROUND

The number of hip fractures occurring worldwide in 1990 was estimated at 1.7 million and is predicted to rise to 6.3 million by 2050. The vast majority occur as a result of simple falls and the impact of the femoral trochanter with the floor. Previous studies have addressed the problem from the patient's side of the impact. Little research has been carried out on the other surface involved in the impact, the floor. STUDY LOCATION: 34 residential care homes.

METHODS

(1) The mechanical properties of the floor were measured with force transducers. (2) The number and location of falls and fractures on the various floors were recorded prospectively for 2 years. The threshold for reporting falls in different care homes was assessed using a standardised set of scenarios.

RESULTS

A total of 6,641 falls and 222 fractures were recorded. Wooden carpeted floors were associated with the lowest number of fractures per 100 falls. The risk of fracture resulting from a fall was significantly lower compared to all other floor types (odds ratio 1.78, 95% CI 1.33-2.35). The mean impact force was significantly lower on wooden carpeted floors: 11.9 kN compared to the other floor types.

DISCUSSION

The possible implications of our findings are considerable. Residents of homes are typically frail and many have a propensity to falls. In designing safer environments for older people, the type of floor should be chosen to minimise the risk of fracture. This may result in a major reduction in fractures in the elderly.

Novel metabotropic glutamate receptor negatively coupled to adenylyl cyclase in cultured rat cerebellar astrocytes

Several excitatory amino acid ligands were found potently to inhibit forskolin-stimulated cAMP accumulation in rat cultured cerebellar astrocytes: L-cysteine sulfinic acid (L-CSA) = L-aspartate > L-glutamate >/= the glutamate uptake inhibitor, L-PDC. This property did not reflect activation of conventional glutamate receptors, since the selective ionotropic glutamate receptor agonists NMDA, AMPA, and kainate, as well as several mGlu receptor agonists [(1S,3R)-ACPD, (S)-DHPG, DCG-IV, L-AP4, L-quisqualate, and L-CCG-I], were without activity. In addition, the mGlu receptor antagonists, L-AP3, (S)-4CPG, Eglu, LY341495, (RS)-CPPG, and (S)-MCPG failed to reverse 30 microM glutamate-mediated inhibitory responses. L-PDC-mediated inhibition was abolished by the addition of the enzyme glutamate-pyruvate transaminase. This finding suggests that the effect of L-PDC is indirect and that it is mediated through endogenously released L-glutamate. Interestingly, L-glutamate-mediated inhibitory responses were resistant to pertussis toxin, suggesting that G(i)/G(o) type G proteins were not involved. However, inhibition of protein kinase C (PKC, either via the selective PKC inhibitor GF109203X or chronic PMA treatment) augmented glutamate-mediated inhibitory responses. Although mGlu3 receptors (which are negatively coupled to adenylyl cyclase) are expressed in astrocyte populations, in our study Western blot analysis indicated that this receptor type was not expressed in cerebellar astrocytes. We therefore suggest that cerebellar astrocytes express a novel mGlu receptor, which is negatively coupled to adenylyl cyclase, and possesses an atypical pharmacological profile.

Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor

PURPOSE

Most gastrointestinal stromal tumors (GISTs) express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. The relationship between mutations in these kinases and clinical response to imatinib was examined in a group of patients with advanced GIST.

PATIENTS AND METHODS

GISTs from 127 patients enrolled onto a phase II clinical study of imatinib were examined for mutations of KIT or PDGFRA. Mutation types were correlated with clinical outcome.

RESULTS

Activating mutations of KIT or PDGFRA were found in 112 (88.2%) and six (4.7%) GISTs, respectively. Most KIT mutations involved exon 9 (n = 23) or exon 11 (n = 85). All KIT mutant isoforms, but only a subset of PDGFRA mutant isoforms, were sensitive to imatinib, in vitro. In patients with GISTs harboring exon 11 KIT mutations, the partial response rate (PR) was 83.5%, whereas patients with tumors containing an exon 9 KIT mutation or no detectable mutation of KIT or PDGFRA had PR rates of 47.8% (P =.0006) and 0.0% (P <.0001), respectively. Patients whose tumors contained exon 11 KIT mutations had a longer event-free and overall survival than those whose tumors expressed either exon 9 KIT mutations or had no detectable kinase mutation.

CONCLUSION

Activating mutations of KIT or PDGFRA are found in the vast majority of GISTs, and the mutational status of these oncoproteins is predictive of clinical response to imatinib. PDGFRA mutations can explain response and sensitivity to imatinib in some GISTs lacking KIT mutations.

Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor

PURPOSE

Most gastrointestinal stromal tumors (GISTs) express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. The relationship between mutations in these kinases and clinical response to imatinib was examined in a group of patients with advanced GIST.

PATIENTS AND METHODS

GISTs from 127 patients enrolled onto a phase II clinical study of imatinib were examined for mutations of KIT or PDGFRA. Mutation types were correlated with clinical outcome.

RESULTS

Activating mutations of KIT or PDGFRA were found in 112 (88.2%) and six (4.7%) GISTs, respectively. Most KIT mutations involved exon 9 (n = 23) or exon 11 (n = 85). All KIT mutant isoforms, but only a subset of PDGFRA mutant isoforms, were sensitive to imatinib, in vitro. In patients with GISTs harboring exon 11 KIT mutations, the partial response rate (PR) was 83.5%, whereas patients with tumors containing an exon 9 KIT mutation or no detectable mutation of KIT or PDGFRA had PR rates of 47.8% (P =.0006) and 0.0% (P <.0001), respectively. Patients whose tumors contained exon 11 KIT mutations had a longer event-free and overall survival than those whose tumors expressed either exon 9 KIT mutations or had no detectable kinase mutation.

CONCLUSION

Activating mutations of KIT or PDGFRA are found in the vast majority of GISTs, and the mutational status of these oncoproteins is predictive of clinical response to imatinib. PDGFRA mutations can explain response and sensitivity to imatinib in some GISTs lacking KIT mutations.

On the unreliability of published DNA sequences

•  Here, the reliability of published fungal nucleic acid sequences is tested by the critical re-evaluation of 206 named sequences obtained from public-access databases. •  Sequences from the ribosomal RNA (rRNA) gene cluster were examined as these are commonly used to establish fungal phylogeny and evolution, and are also increasingly employed in the identification of fungi from nonculture based studies. •  Fifty-one rRNA internal transcribed spacer (ITS) sequences were obtained for species of Amanita, 55 ITS sequences were obtained for species of Phoma and 100 rRNA small subunit sequences were obtained from representative genera of the order Helotiales. In each case, the fungal group was selected partly on the basis of sequences deposited by three or more laboratories in order to avoid sample bias. The results suggest that up to 20% of the sequences available for each group may be unreliable, and this proportion is supported by additional informal observations.

Infective discitis with Neisseria sicca/subflava in a previously healthy adult

STUDY DESIGN

A case report of Neisseria sicca/subflava discitis in a healthy elderly female.

OBJECTIVE

To report a rare case, which is usually seen exclusively in children.

SETTING

Stoke on Trent, England.

METHOD

Case report, a 65-year-old female with a 6 month history of back and bilateral leg pain. X-rays showed collapse of L4/5 disc. No neurological deficit. Magnetic resonance imaging supported the clinical suspicion of discitis. Percutaneous biopsy followed 2 weeks later by open biopsy with bilateral root decompression was performed. Culture of L4/5 disc tissue produced Neisseria sicca/subflava. The patient was treated with a 4-week course of intravenous amoxycillin. Follow-up at 3 months confirmed clinical resolution of original symptoms.

CONCLUSION

Any organism cultured from biopsy needs to be interpreted within the context of the clinical case. If clinical suspicion is high, further weight must be added to the finding of unusual or environmental organisms and culture of a repeat aspirate or biopsy may clarify the significance.

Disease-dependent adhesion of lactic acid bacteria to the human intestinal mucosa

Their adhesion to the intestinal mucosa is considered one of the main reasons for the beneficial health effects of specific lactic acid bacteria (LAB). However, the influence of disease on the mucosal adhesion is largely unknown. Adhesion of selected LAB to resected colonic tissue and mucus was determined in patients with three major intestinal diseases (i.e., diverticulitis, rectal carcinoma, and inflammatory bowel disease) and compared to healthy control tissue. All strains were observed to adhere better to immobilized mucus than to whole intestinal tissue. Two strains (Lactobacillus rhamnosus strain GG and L. reuteri) were found to exhibit disease-specific adhesion to intestinal tissue. All tested strains, with the exception of L. rhamnosus strain GG, displayed disease-specific adhesion to intestinal mucus. These results suggest that strains with optimal binding characteristics for a particular intestinal disease can be selected.

Relapsing encephalopathy following small bowel transplantation

We report a case of a 40-year-old man presenting with relapsing encephalopathy 4 years post-intestinal transplantation. Each episode was preceded by symptoms suggestive of subacute intestinal obstruction, marked dehydration, and, on one occasion, grade 4 encephalopathy. Physical examination revealed hypertonia, clonus, and hyperreflexia. Biochemistry was consistent with renal impairment, metabolic alkalosis, hyperammonaemia, and normal liver function. Plain radiographs and abdominal computed tomography revealed dilated proximal small bowel loops, and barium radiography demonstrated a strictured distal anastomosis. Hydrogen breath testing indicated bacterial overgrowth. Following rehydration and antibiotic therapy, the patient recovered fully between episodes. Further episodes of encephalopathy did not recur following resection of the distal anastomotic stricture and resolution of bacterial overgrowth. Unfortunately, one year later the patient died of pneumonia. To the best of our knowledge, encephalopathy secondary to intestinal transplant related porto-caval shunt and bacterial overgrowth in strictured bowel has not been previously reported but might have implications for the management of future patients.