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Regulation of mRNA localization by transmembrane signalling: local interaction of HB-GAM (heparin-binding growth-associated molecule) with the cell surface localizes beta-actin mRNA.

Localization of mRNAs is currently thought to be partially responsible for molecular sorting to specific compartments within the cell. In mammalian cells the best-studied example is the beta-actin mRNA that is localized to the cell processes, and its localization is necessary in migratory responses of cells. It is reasonable to assume that mRNA localization within cells is coupled to transmembrane signalling due to extracellular factors, but little is known about such putative mechanisms. We show here that HB-GAM, an extracellular matrix-associated factor that enhances migratory responses in cells, is able to localize beta-actin mRNA when locally applied to cells via microbeads. The HB-GAM-induced mRNA localization is specifically inhibited by low concentrations of heparin and by heparitinase treatment of cells, showing that cell-surface heparin-type glycans are required for the effect. The finding that soluble N-syndecan is also inhibitory suggests that the transmembrane proteoglycan N-syndecan, previously identified as an HB-GAM receptor, is involved in the mRNA-localizing effect of HB-GAM. Inhibition of the mRNA localization by the src-kinase inhibitor PP1 is compatible with an N-syndecan-mediated effect since the receptor function of N-syndecan has been recently found to depend on the src-kinase signalling pathway. The mRNA-localizing activity of N-syndecan is also suggested by the finding that affinity-purified anti-N-syndecan antibodies coated on microbeads are able to localize beta-actin mRNA.

Actins↗

From local hybrid functionals to "localized local hybrid" potentials: formalism and thermochemical tests.

Hybrid exchange-correlation functionals with position-dependent exact-exchange admixture (local hybrid functionals) have been implemented self-consistently for the first time. Functional derivatives with respect to the occupied orbitals have been derived and were subsequently transformed into local and multiplicative potentials within the framework of the optimized effective potential. The resulting local and multiplicative Kohn-Sham potentials are termed "localized local hybrid" (LLH) potentials. They have been evaluated in calculations of atomization energies for a series of main-group molecules. It is shown that LLH potentials yield somewhat better thermochemical results than non-self-consistent post-GGA calculations with the same local hybrid energy functionals for orbitals obtained with a different potential. The choice of the "local mixing function" (LMF) is discussed. This is the key quantity for the performance of local hybrid functionals that determines the amount of exact-exchange admixture at a given point in space. Careful analyses of average exact-exchange admixtures and of the spatial variation of two different LMFs for various molecules provide insight into the shortcomings of the currently used local hybrid functionals. Beyond a too large average exact-exchange admixture, both LMFs used appear to provide an unbalanced description of exact-exchange admixture across bonds to hydrogen. LLH potentials open the way for property calculations with local hybrid functionals.

Journal Article↗

Target localization and real-time tracking using the Calypso 4D localization system in patients with localized prostate cancer.

PURPOSE: The Calypso 4D Localization System is being developed to provide accurate, precise, objective, and continuous target localization during radiotherapy. This study involves the first human use of the system, to evaluate the localization accuracy of this technique compared with radiographic localization and to assess its ability to obtain real-time prostate-motion information. METHODS AND MATERIALS: Three transponders were implanted in each of 20 patients. Eleven eligible patients of the 20 patients participated in a study arm that compared radiographic triangulated transponder locations to electromagnetically recorded transponder locations. Transponders were tracked for 8-min periods. RESULTS: The implantations were all successful, with no major complications. Intertransponder distances were largely stable. Comparison of the patient localization on the basis of transponder locations as per the Calypso system with the radiographic transponder localization showed an average (+/-SD) 3D difference of 1.5 +/- 0.9 mm. Upon tracking during 8 min, 2 of the 11 patients showed significant organ motion (>1 cm), with some motion lasting longer that 1 min. CONCLUSION: Calypso transponders can be used as magnetic intraprostatic fiducials. Clinical evaluation of this novel 4D nonionizing electromagnetic localization system with transponders indicates a comparable localization accuracy to isocenter, (within 2 mm) compared with X-ray localization.

Electromagnetic Phenomena↗

Isolated limb perfusion for localized melanoma of the extremity. A matched comparison of wide local excision with isolated limb perfusion and wide local excision alone.

The therapeutic efficacy of isolated limb perfusion in patients with localized melanoma of the extremity remains controversial. We compared patients treated at the University of Texas M.D. Anderson Cancer Center, Houston, with wide local excision and isolated limb perfusion using either melphalan or imidazole carboxamide with a group matched for prognostic factors from the University of Alabama at Birmingham and the University of Sydney (Australia) who were treated with wide local excision alone. No significant difference in disease-free or overall survival rates was found between patients treated with wide local excision with adjuvant isolated limb perfusion or wide local excision alone. However, a subset of patients with thicker lesions (greater than 2.0 mm) treated with wide local excision and isolated limb perfusion using melphalan had a significant improvement in both disease-free and overall survival rates. These data suggest that isolated limb perfusion using melphalan may improve survival rates in selected patients with localized melanoma of the extremity who are at increased risk for local and regional micrometastases, and justifies the continued study of this treatment approach in prospective clinical trials.

Aminoimidazole Carboxamide↗

Decreases of local brain temperature due to convection (local brain blood flow) and increases of local brain temperature due to activity.

The influence of local brain blood flow upon variations of local brain temperature in chronical experiments was investigated in cats. It was found that changes of local brain temperature in chronic experiments are esclusively due to changes of local metabolic heat production as long as the temperature of brain inflowing blood remains constant. Decreases of temperature due to convection (increase of local blood flow) are smaller than increases of temperature due to activity.

Animals↗

Therapeutic strategies for localized and locally advanced prostate cancer: combining androgen suppression with definitive local therapy.

Patients with locally advanced prostate cancer (clinical category T3,4) managed with external beam radiation therapy (EBRT) and 3 years of androgen suppression therapy (AST) compared with patients managed with EBRT alone have been shown to have a survival benefit. Studies addressing the same question in patients with clinically localized disease (T1,2) are now completed and await follow-up. A decrease in positive surgical margins has been noted; however, no benefit in prostate-specific antigen (PSA) control has been documented in any of several randomized studies in which the addition of 3 months of neoadjuvant AST was administered before radical prostatectomy. Randomized data now show that dose-escalated radiation provides superior PSA control rates compared with conventional-dose radiation therapy for patients with localized prostate cancer. How best to administer high-dose radiation (eg, intensity modulated radiation therapy, or 3-dimensional conformal radiation therapy with or without a brachytherapy boost), and how best to integrate high-dose radiation for patients with high-risk localized or locally advanced prostate cancer remain under investigation.

Journal Article↗

The sequential change of local cerebral blood flow and local cerebral glucose metabolism after focal cerebral ischaemia and reperfusion in rat and the effect of MK-801 on local cerebral glucose metabolism.

In order to investigate the time course change of local cerebral blood flow (1CBF) and local cerebral glucose metabolism (ICGM) and the effect of MK-801 (dizocilpine), an NMDA receptor antagonist on glucose metabolism in a middle cerebral artery occlusion-reperfusion model, 14C-Iodo-antipyrine and 14C-Deoxyglucose autoradiographic method have been used. The 1CBF was reduced to 0-10% of the control level in the ischaemic core and to 12-40% in the ischaemic penumbra between 60 and 120 min after the onset of the ischaemia. In the ischaemic core, the marked hyperfusion appeared at 15 min and maintained about 30 to 45 min following reperfusion. In the ischaemic penumbra, the hyperfusion during reperfusion was not found. Hypermetabolism occurred at 30 min and reached to the peak at 60 min after the middle cerebral artery (MCA) occlusion both in the ischaemic core and in the penumbra. The shift from hyper- to hypometabolism was observed during the ischaemia. The reperfusion following 2 hours of MCA occlusion facilitated the decrease of cerebral glucose metabolism in the ischaemic region. The pretreatment of MK-801 (0.4 mg/kg) inhibited both increased glucose metabolism during the ischaemia and decreased glucose metabolism during the reperfusion. The effect of limiting decreased glucose metabolism during the reperfusion by MK-801 was remarkable in the ischaemic penumbra. These findings support the hypothesis that excitation-induced hypermetabolism play a major role in the ischaemic insult following focal cerebral vascular occlusion.

Animals↗

Organ- and treatment-specific local response rates to systemic and local treatment modalities in stage IV melanoma.

BACKGROUND: Metastatic melanoma shows different local response rates in organs to systemic or local treatment modalities. Whereas skin, soft tissue, lymph node and lung metastases seem to have better local response rates, the local response of metastases localized in the liver, brain and bone seems to be low. OBJECTIVES: The organ-specific response rate, local response rate of each therapeutic measure and survival of 68 patients with stage IV disease were evaluated. METHODS: Four hundred and ten treatment periods (1-18 per patient) in 17 different organs of 43 men and 25 women (mean age 55 years, range 19-79) with measurable, widespread, surgically incurable disease were analysed. Chemotherapy was given in 405 of 410 treatment periods with dacarbazine, fotemustine, vindesine, carboplatin and temozolomide in different schedules. Local treatment modalities comprising radiotherapy, gamma knife radiosurgery and local hyperthermia were given in 71 of 410 treatment periods. RESULTS: Local response (complete or partial local remission) was achieved in 52 treatment periods (12.7%). When local treatment modalities, either combined with systemic therapy or not, were compared with systemic therapeutic modalities alone, a local response of 24% was achieved with local measures, compared with 10% in systemic treatment only (P = 0.003). When a spontaneous remission rate of less than 5% is considered, however, local as well as systemic treatments had a significant effect (P < 0.001). Organ-specific response rates to local therapies showed no statistically significant differences between the various organs involved. When systemic treatments without local measures were taken into account, lung metastases, cutaneous/subcutaneous metastases and adrenal metastases performed significantly better than liver metastases. When different treatment modalities were considered, there was no significant difference between the three local measures applied (radiotherapy, gamma knife radiosurgery and hyperthermia). Among the systemic therapies, dacarbazine high dose and carboplatin monochemotherapy were superior to combined regimens using fotemustine. A local response, irrespective of the mode of therapy, was significantly associated with longer survival (median 16 months) compared with no local response or local progressive disease (median 7 months; P < 0.0001). When the first treatment period of each patient was considered, local response was no longer a significant predictor. CONCLUSIONS: The study shows that local therapeutic measures are superior in inducing a local response than systemic therapies alone. Induction of remission may be associated with longer survival. Chemotherapy, despite limited local response rates, is still statistically superior to an estimated spontaneous remission rate.

Adult↗

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗

Local corticosteroid injection for carpal tunnel syndrome.

BACKGROUND: Carpal tunnel syndrome (CTS) is a clinical syndrome manifested by signs and symptoms of irritation of the median nerve at the level of the carpal tunnel in the wrist. Treatment of CTS can be surgical or non-surgical. Local corticosteroid injection for CTS has been previously studied but most studies have been either retrospective or uncontrolled. The effectiveness and duration of benefit of local corticosteroid injection for CTS remain unknown. OBJECTIVES: To evaluate the effectiveness of local steroid injection for carpal tunnel syndrome versus placebo injection or other non-surgical interventions in improving clinical outcome and to determine the length of symptom relief post injection. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group register, MEDLINE, EMBASE and CINAHL. SELECTION CRITERIA: Studies using either a randomized or quasi-randomized methodology were eligible for inclusion. The studies included participants with the diagnosis of carpal tunnel syndrome and the treatment intervention was local corticosteroid injection. The primary outcome measure was clinical improvement after injection. DATA COLLECTION AND ANALYSIS: Three reviewers independently selected the trials to be included in the study. Studies were rated for their overall quality independently by the reviewers. Studies were compared for heterogeneity using the chi square statistic. Relative risks and 95% confidence intervals were calculated for each trial and summary relative risks and 95% confidence intervals (CI) were also calculated. MAIN RESULTS: We identified four randomized controlled trials studying local corticosteroid injection for the treatment of CTS. Two trials were excluded. One did not include clinical assessment as an outcome and the other did not provide patient outcomes, but only statistical values. Each of the remaining two trials had demonstrated clinical improvement of CTS at one month following local corticosteroid injection compared to placebo injection. The pooled relative risk (RR) favouring treatment was 3.62 (95% CI 1.94 to 6.73). REVIEWER'S CONCLUSIONS: Local corticosteroid injection for CTS provides greater clinical improvement in symptoms one month after injection compared to placebo. Symptom relief beyond one month compared to placebo has not been demonstrated. The effectiveness of local corticosteroid injection has not been compared to other non-surgical or surgical interventions for CTS in randomized controlled trials.

Adrenal Cortex Hormones↗

Local-regional treatment of patients with simultaneous local-regional recurrence and distant metastases following mastectomy.

High-dose, large volume local-regional irradiation has been shown to be necessary in patients with local-regional recurrence of breast cancer without coexisting distant metastases; however, no studies exist that deal with the dose and volume of local-regional irradiation required for patients with both local-regional recurrence and distant metastases. This report is an analysis of 68 patients who presented with previously untreated local-regional recurrence and coexisting distant metastases. Thirty-five of these patients were treated with local-regional irradiation and systemic therapy; the remaining 33 patients received systemic therapy only. An analysis of the dose and volume in the 35 irradiated patients showed that if the irradiation was inadequate (dose less than 4500 rad and volume not large enough to encompass the entire involved site), the incidence of uncontrolled local-regional disease for the duration of life was 79%, similar to the 64% rate of uncontrolled local-regional disease in the 33 patients not receiving local-regional irradiation. On the other hand, if the dose to the recurrence was at least 4500 rad and if the field was large enough to encompass the entire site containing the recurrence, the incidence of uncontrolled local-regional disease for the duration of life was only 27%. The present study also suggests that local-regional irradiation may be indicated in patients with asymptomatic as well as symptomatic local-regional disease. In patients with distant metastases and initially asymptomatic local-regional disease, adequate irradiation resulted in a lower incidence of ultimate local-regional symptoms when compared to similar patients who were treated with inadequate or no local-regional irradiation. This difference was not quite statistically significant because of the small number of patients in each group.

Breast Neoplasms↗

Covariation analysis of local amino acid sequences in recurrent protein local structures.

Local structural information is supposed to be frequently encoded in local amino acid sequences. Previous research only indicated that some local structure positions have specific residue preferences in some particular local structures. However, correlated pairwise replacements for interacting residues in recurrent local structural motifs from unrelated proteins have not been studied systematically. We introduced a new method fusing statistical covariation analysis and local structure-based alignment. Systematic analysis of structure-based multiple alignments of recurrent local structures from unrelated proteins in representative subset of Protein Databank indicates that covarying residue pairs with statistical significance exist in local structural motifs, in particular beta-turns and helix caps. These residue pairs are mostly linked through polar functional groups with direct or indirect hydrogen bonding. Hydrophobic interaction is also a major factor in constraining pairwise amino acid residue replacement in recurrent local structures. We also found correlated residue pairs that are not clearly linked with through-space interactions. The physical constrains underlying these covariations are less clear. Overall, covarying residue pairs with statistical significance exist in local structures from unrelated proteins. The existence of sequence covariations in local structural motifs from unrelated proteins indicates that many relics of local relations are still retained in the tertiary structures after protein folding. It supports the notion that some local structural information is encoded in local sequences and the local structural codes could play important roles in determining native state protein folding topology.

Algorithms↗

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗

Enhancement of local control in locally advanced node-positive nasopharyngeal carcinoma by adjunctive chemotherapy.

PURPOSE: To determine the efficacy of chemotherapy adjunctive to radical radiotherapy (neoadjuvant +/- adjuvant) in patients with node-positive nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: All the node-positive patients given adjunctive chemotherapy between 1984-1989 (n = 209, CHEMO) were compared with all the node-positive patients treated by radical radiotherapy alone during the same period (n = 409, NCHEMO). The CHEMO group had significantly more bulky nodes, lower cervical/supraclavicular nodes, and more advanced overall stages than the NCHEMO group because nodal size (> or =24 cm) was used as a selection criterion for chemotherapy (1984-1988 departmental protocol and 1988-1989 prospective randomized trial). The chemotherapy consisted of two courses of neoadjuvant cisplatin (100 mg/m2 D1) and 5-fluorouracil (5-FU) (1 gm/m2 D1-D3) in 191 patients. In addition to the two courses of neoadjuvant, four courses of adjuvant chemotherapy, of the same combination, were given after radical radiotherapy in a further 18 patients. Radical radiotherapy delivered a nasopharyngeal dose of 60-62.5 Gy. In addition, parapharyngeal booster external radiotherapy (20 Gy) was given in the presence of parapharyngeal involvement, and intracavitary brachytherapy (24 Gy) was used to treat any local residual tumor diagnosed at 4-6 weeks after external radiotherapy. Both crude and actuarial rates were compared (survival, distant metastases, and local failures) between CHEMO and NCHEMO for all patients, for individual Ho's overall stage, for patients with nodes of different sizes (< or =3 cm, >3-< or =6 cm, >6 cm), for individual T-stage and individual N-stage, and for patients belonging to different gender and different age groups (<40 years, > or =40 years). Multivariate analyses using the Cox Regression Model were performed to identify significant prognostic factors. RESULTS: With a median follow-up of 5.5 years (range 0.7 to 10 years), CHEMO had significantly less local failures overall than NCHEMO; this was especially true for patients with advanced stages (III + IV). Additionally, in all nodal-size subgroups, in all node-positive T3, and in node-positive T3-Stage IV, there was a significant reduction in local failures after chemotherapy. There was a trend toward fewer local failures in favor of chemotherapy in Stage III, Stage IV, and T3-Stage III (0.05<p< or =0.1). There was no difference in local failures between CHEMO and NCHEMO in Stage II or in T1 and T2. The multivariate analyses identified the administration of adjunctive chemotherapy to be of independent significance in determining the local failure rate for all patients, the T3 (node-positive), and the advanced overall stages (III and IV combined). There was no difference in overall survival, relapse-free survival, and distant metastasis rates between CHEMO and NCHEMO among patients belonging to Stages III and IV despite the presence of more advanced nodal diseases in CHEMO. There were very few late local relapses in patients given adjunctive chemotherapy, in contradistinction to the well-known predisposition of NPC to late local relapses after radical radiotherapy. CONCLUSION: Adjunctive chemotherapy enhanced local control in node-positive NPC in general, and node positive-T3 and -T3-Stage IV in particular with reduction of late local relapses. The enhancement in local control of the locally advanced NPC could be explained by the significant shrinkage of the primary tumor by the neoadjuvant chemotherapy, leading to an increased safety margin between the tumor volume and the radiation volume. We recommend that adjunctive chemotherapy (neoadjuvant +/- adjuvant) should become an integral part of the multimodality curative treatment for patients with node-positive T3 NPC.

Adolescent↗

Local structure-based sequence profile database for local and global protein structure predictions.

MOTIVATION: A large body of evidence suggests that protein structural information is frequently encoded in local sequences-sequence-structure relationships derived from local structure/sequence analyses could significantly enhance the capacities of protein structure prediction methods. In this paper, the prediction capacity of a database (LSBSP2) that organizes local sequence-structure relationships encoded in local structures with two consecutive secondary structure elements is tested with two computational procedures for protein structure prediction. The goal is twofold: to test the folding hypothesis that local structures are determined by local sequences, and to enhance our capacity in predicting protein structures from their amino acid sequences. RESULTS: The LSBSP2 database contains a large set of sequence profiles derived from exhaustive pair-wise structural alignments for local structures with two consecutive secondary structure elements. One computational procedure makes use of the PSI-BLAST alignment program to predict local structures for testing sequence fragments by matching the testing sequence fragments onto the sequence profiles in the LSBSP2 database. The results show that 54% of the test sequence fragments were predicted with local structures that match closely with their native local structures. The other computational procedure is a filter system that is capable of removing false positives as possible from a set of PSI-BLAST hits. An assessment with a large set of non-redundant protein structures shows that the PSI-BLAST + filter system improves the prediction specificity by up to two-fold over the prediction specificity of the PSI-BLAST program for distantly related protein pairs. Tests with the two computational procedures above demonstrate that local sequence-structure relationships can indeed enhance our capacity in protein structure prediction. The results also indicate that local sequences encoded with strong local structure propensities play an important role in determining the native state folding topology.

Algorithms↗

Two copies of a subelement from the Vg1 RNA localization sequence are sufficient to direct vegetal localization in Xenopus oocytes.

Localization of mRNA has emerged as a fundamental mechanism for generating polarity during development. In vertebrates, one example of this phenomenon is Vg1 RNA, which is localized to the vegetal cortex of Xenopus oocytes. Vegetal localization of Vg1 RNA is directed by a 340-nt sequence element contained within its 3' untranslated region. To investigate how such cis-acting elements function in the localization process, we have undertaken a detailed analysis of the precise sequence requirements for vegetal localization within the 340-nt localization element. We present evidence for considerable redundancy within the localization element and demonstrate that critical sequences lie at the ends of the element. Importantly, we show that a subelement from the 5' end of the Vg1 localization element is, when duplicated, sufficient to direct vegetal localization. We suggest that the Vg1 localization element is composed of smaller, redundant sequence motifs and identify one such 6-nt motif as essential for localization. These results allow insight into what constitutes an RNA localization signal and how RNA sequence elements may act in the localization process.

Animals↗

Local reactivity, local resistance and systemic dissemination in Mycobacterium lepraemurium (MLM) infection.

Local reactivity measured as swelling of the infected footpad, local resistance to bacterial multiplication, and capacity to limit systemic dissemination were studied in C57BL, C3H/Bom, C3H/HeJ, and A/Sn mice inoculated with Mycobacterium lepraemurium. C57BL mice developed a strong local reaction with a sudden onset, and effectively limited local multiplication as well as systemic dissemination of bacteria to the liver and spleen as determined 19 weeks after the inoculation. C3H/Bom mice showed no local reaction, had high numbers of bacteria locally, and had extensive systemic dissemination of the infection. C3H/HeJ mice, on the other hand, developed a small local reaction and had less systemic dissemination of bacteria than C3H/Bom mice. In C57BL mice and in the two C3H substrains local reactivity, local resistance to infection, and resistance to systemic spread of the infection paralleled each other. In contrast, A/Sn mice showed a small local reaction, had the most extensive bacterial multiplication at the site of inoculation of the four mouse strains tested, and at the same time were the mice that most effectively restricted systemic dissemination of the infection. Thus, the mechanisms restricting local bacterial multiplication may be different from the mechanisms limiting bacterial dissemination. Neither bacterial growth locally at the site of subcutaneous inoculation in the footpad, nor systemic dissemination of the infection, followed a mouse strain pattern consistent with the Ity/Lsh/Bcg gene model. In experimental mycobacterial infection both local bacterial growth at the site of inoculation and systemic dissemination should be determined.

Animals↗

Combined chemotherapy and radiotherapy (without surgery) compared with radiotherapy alone in localized carcinoma of the esophagus.

BACKGROUND: Esophageal carcinoma can be managed primarily with either a surgical or radiotherapeutic (non surgical) approach. Strategies to improve the outcome of either modality alone include the use of combined modalities. Combination chemotherapy radiotherapy is one approach that has been explored over the years with increasing application in clinical practice especially in North America. OBJECTIVES: To evaluate the effectiveness of combined chemotherapy and radiotherapy versus radiotherapy alone in the outcome of patients with localized esophageal carcinoma. Outcomes of interest include overall survival, cause specific survival, local recurrence, dysphagia relief, quality of life, acute and chronic toxicities. SEARCH STRATEGY: The Cochrane strategy for identifying randomized trials was combined with MeSH headings including esophageal neoplasms, radiotherapy, chemotherapy combined modality, drug therapy combination. Medline, Cancerlit and Embase were searched using this strategy. In addition, the Cochrane library was also searched. References from relevant articles and personal files were included. SELECTION CRITERIA: Randomized controlled trials in patients with localized esophageal cancer, with one arm employing radiotherapy alone, and one arm employing combination radiotherapy chemotherapy were included. Studies comparing non chemotherapy agents such as pure radiotherapy sensitisers, immunostimulants, planned esophagectomy, were excluded. DATA COLLECTION AND ANALYSIS: Data were extracted by two independent reviewers, and the trial quality was assessed using both the Jadad scoring and Detsky checklist. Sensitivity analysis was planned to explore sources of heterogeneity where heterogeneity existed. The factors hypothesized a priori included combination versus sequential treatment, quality of study, biological effective radiotherapy dose (i.e. Radiotherapy dose) cisplatin versus non cisplatin containing trials, and 5FU versus non 5FU containing trials. Odds Ratio (OR) and 95% confidence limits were used to assess the significance of the difference between the treatment arms. Absolute risk difference and number needed to treat (NNT) were used to express the magnitude of difference where appropriate. MAIN RESULTS: Thirteen randomized trials were included in the analysis. There were eight concomitant and five sequential radiotherapy and chemotherapy (RTCT) studies. The studies were analyzed separately due to observed heterogeneity across all the studies and biological considerations. Concomitant RTCT provided significant overall reduction in mortality at 1 and 2 years. The mortality in the control arms was 67% and 86% respectively. Combined RTCT provided an absolute reduction of mortality by 9% (95% CI 2-17%) and 8% (95% CI 1-17%) respectively. Expressed as NNT, this is 11 and 10 respectively. At longer follow up, the results were heterogeneous, cautioning against pooling of the data. There was a reduction in the overall local recurrence rate. The local recurrence rate for the control arms was in the order of 69%. Combined RTCT provided an absolute reduction of local recurrence rate of 5% (95% CI 4-26%) with a NNT of 7. There was significant increase of severe and life threatening toxicities with a NNH of 6, with this approach. With the sensitivity analysis, there was a suggestion that cisplatin based and 5FU based chemotherapy studies were reasonable regimens to employ when using this strategy. The results from the sequential RTCT studies were heterogeneous and could not be pooled. Factors hypothesized a priori did not identify any single source that could account for a significant component of the heterogeneity. Examining the results individually, there was no data to support clinical benefit. This approach was also accompanied by significant toxicities. REVIEWER'S CONCLUSIONS: When a non-operative approach is selected, then concomitant RTCT is superior to the RT alone. This approach is accompanied by significant toxicities. In patients who are in good general condition, and the risk benefit has been thoroughly discussed with the patient, concomitant RTCT should be considered for the management of esophageal cancer compared with radiotherapy alone.

Combined Modality Therapy↗