Persistence and resistance as complementary bacterial adaptations to antibiotics.

Bacterial persistence represents a simple of phenotypic heterogeneity, whereby a proportion of cells in an isogenic bacterial population can survive exposure to lethal stresses such as antibiotics. In contrast, genetically based antibiotic resistance allows for continued growth in the presence of antibiotics. It is unclear, however, whether resistance and persistence are complementary or alternative evolutionary adaptations to antibiotics. Here, we investigate the co-evolution of resistance and persistence across the genus Pseudomonas using comparative methods that correct for phylogenetic nonindependence. We find that strains of Pseudomonas vary extensively in both their intrinsic resistance to antibiotics (ciprofloxacin and rifampicin) and persistence following exposure to these antibiotics. Crucially, we find that persistence correlates positively to antibiotic resistance across strains. However, we find that different genes control resistance and persistence implying that they are independent traits. Specifically, we find that the number of type II toxin-antitoxin systems (TAs) in the genome of a strain is correlated to persistence, but not resistance. Our study shows that persistence and antibiotic resistance are complementary, but independent, evolutionary adaptations to stress and it highlights the key role played by TAs in the evolution of persistence.

Correlation between response to neoadjuvant chemotherapy and survival in locally advanced breast cancer patients.

BACKGROUND: Measurement of residual disease following neoadjuvant chemotherapy that accurately predicts long-term survival in locally advanced breast cancer (LABC) is an essential requirement for clinical trials development. Several methods to assess tumor response have been described. However, the agreement between methods and correlation with survival in independent cohorts has not been reported. PATIENTS AND METHODS: We report survival and tumor response according to the measurement of residual breast cancer burden (RCB), the Miller and Payne classification and the Response Evaluation Criteria in Solid Tumors (RECIST) criteria, in 151 LABC patients. Kappa Cohen's coefficient (К) was used to test the agreement between methods. We assessed the correlation between the treatment outcome and overall survival (OS) and relapse-free survival (RFS) by calculating Harrell's C-statistic (c). RESULTS: The agreement between Miller and Payne classification and RCB classes was very high (К = 0.82). In contrast, we found a moderate-to-fair agreement between the Miller and Payne classification and RECIST criteria (К = 0.52) and RCB classes and RECIST criteria (К = 0.38). The adjusted C-statistic to predict OS for RCB index (0.77) and RCB classes (0.75) was superior to that of RECIST criteria (0.69) (P = 0.007 and P = 0.035, respectively). Also, RCB index (c = 0.71), RCB classes (c = 0.71) and Miller and Payne classification (c = 0.67) predicted better RFS than RECIST criteria (c = 0.61) (P = 0.005, P = 0.006 and P = 0.028, respectively). CONCLUSIONS: The pathological assessment of tumor response might provide stronger prognostic information in LABC patients.

Glutathione S-transferase P1 c.313A > G polymorphism could be useful in the prediction of doxorubicin response in breast cancer patients.

BACKGROUND: Identification of predicting factors for anthracyclines-based chemotherapy remains a clinical challenge. Glutathione S-transferase (GSTs) enzymes detoxify chemotherapy drugs and their metabolites. Several polymorphisms in GST genes result in reduced or no activity of the enzymes. Specifically, GSTM1 and GSTT1 genes are polymorphically deleted, the polymorphism GSTP1 c.313A>G (rs1695) determines the amino acid substitution Ile105Val, where the Val-containing enzyme has reduced activity. Also, GSTA1*B allele has reduced levels of GSTA1 enzyme. Several polymorphisms in GSTs have been associated with differences in survival for cancer patients treated with chemotherapy. PATIENTS AND METHODS: We genotyped a total of five polymorphisms in GSTM1, GSTT1, GSTP1 and GSTA1 genes in 159 patients with locally advanced breast cancer, treated with single-agent doxorubicin or docetaxel (Taxotere). Gene expression microarrays were performed in 67 breast tumor samples. We correlate this data with treatment outcome. RESULTS: In multivariate analysis, patients homozygous GG for GSTP1 c.313A>G SNP had a lower risk of chemoresistance when treated with doxorubicin (odds ratio 0.106; confidence interval 0.012-0.898; P=0.040). No association was found in the docetaxel arm. Also, we found that GSTP1 expression varied significantly among breast cancer molecular subtypes. CONCLUSIONS: GSTP1 may constitute another tool contributing to individualized anthracycline-based therapy.

Prospective transGEICAM study of the impact of the 21-gene Recurrence Score assay and traditional clinicopathological factors on adjuvant clinical decision making in women with estrogen receptor-positive (ER+) node-negative breast cancer.

BACKGROUND: This study examined the impact of the Recurrence Score (RS) in Spanish breast cancer patients and explored the associations between clinicopathological markers and likelihood of change in treatment recommendations. PATIENTS AND METHODS: Enrollment was offered consecutively to eligible women with estrogen receptor-positive; human epidermal growth factor receptor 2-negative, node-negative breast cancer. Oncologists recorded treatment recommendation and confidence in it before and after knowing the patient's RS. RESULTS: Treatment recommendation changed in 32% of 107 patients enrolled: in 21% from chemohormonal (CHT) to hormonal therapy (HT) and in 11% from HT to CHT. RS was associated with the likelihood of change from HT to CHT (P < 0.001) and from CHT to HT (P < 0.001). Confidence of oncologists in treatment recommendations increased for 60% of cases. Higher tumor grade (P = 0.007) and a high proliferative index (Ki-67) (P = 0.023) were significantly associated with a greater chance of changing from HT to CHT, while positive progesterone receptor status (P = 0.002) with a greater probability of changing from CHT to HT. CONCLUSIONS: Results from the first prospective European study are consistent with published experience and use of the RS as proposed in European clinical practice guidelines and provide evidence on how Oncotype DX and clinicopathological factors are complementary and patient selection may be improved.

Genomic predictors of response to doxorubicin versus docetaxel in primary breast cancer.

UNLABELLED: Taxanes and anthracyclines improve the outcome of early breast cancer, although the benefit is limited to a small proportion of patients and are toxic. We prospectively looked for predictors of response to these drugs. EXPERIMENTAL DESIGN: Four cycles of doxorubicin (75 mg/m²) or docetaxel (100 mg/m²) were compared as presurgical chemotherapy for breast cancer. Biomarkers were determined by immunohistochemistry and fluorescent in situ hybridization using prechemotherapy core biopsies. Tumors were also classified into one of the molecular intrinsic subtypes using an immunohistochemical panel of five biomarkers and genomic profiles. Single genes and intrinsic subtypes were correlated with response to doxorubicin versus docetaxel. Among the 204 evaluable patients, significant predictors of sensitivity in multivariate analysis were low topo2a expression and ER-negative status for doxorubicin and small tumor size and ER-negative status for docetaxel. Predictors of resistance in multivariate analysis were triple-negative status (ER/PgR/HER2 negative by IHC/FISH) for doxorubicin, and high TNM stage for docetaxel. Triple-negative tumors were associated with topo2a overexpression more than the other subtypes. In 94 patients with gene expression profiles, docetaxel was superior to doxorubicin in the basal-like subtype (good pathological response rate - PCR + class I of 56 vs. 0%; P = 0.034); no significant differences were observed in the other subtypes when comparing these two drugs. Low topo2a expression and ER-negative status were predictors of response to doxorubicin, while small tumor size and ER-negative status predicted response to docetaxel. Docetaxel was superior to doxorubicin in triple-negative/basal-like tumors, while no significant differences were seen in the remaining intrinsic subtypes.

Study of the effector mechanism involved in the production of haemorrhagic necrosis of the small intestine in rat passive anaphylaxis.

1. The effector mechanism of intestinal necrosis in rat anaphylaxis was studied following several complementary approaches: (i) the use of monoclonal antibodies (mAb) belonging to different classes (IgG1, IgG2b and IgE anti-DNP), (ii) the assay of mediators, and (iii) the use of pharmacological tools. 2. Lethality and haemorrhagic necrosis of the small intestine were observed in IgE-sensitized rats, whereas IgG mAb produced milder physiological disturbances. 3. Inhibition of leukotriene biosynthesis reduced the drop of systemic blood pressure (BP) and the extent of protein-rich plasma exudation but it did not influence the haemorrhagic component of intestinal necrosis. 4. The antihistamine, pyrilamine, partially diminished the haemorrhagic component of the intestinal necrosis. 5. The involvement of mediators related to platelet-activating factor (PAF) was studied by examining the pharmacological effects of these autacoids and of PAF-receptor antagonists (PCA4248, UR12460 and BB823). PAF induced intestinal lesions similar to those observed in IgE-sensitized rats and PAF-receptor antagonists markedly decreased haemorrhage in IgE-sensitized rats. 6. PAF levels were transiently increased after dinitrophenol (DNP)- bovine serum albumin (BSA) challenge in the small intestine of IgE-sensitized rats. 7. These data stress differences in the outcome of anaphylaxis related to the type of receptors for the Fc portion of immunoglobulins that are involved. IgE is the antibody class that elicits the most severe response due to the activation of mast cells via Fc epsilon RI (surface receptors that bind IgE antibodies with high affinity), and the only one able to produce intestinal haemorrhagic necrosis. 8. The mast-cell-derived mediators PAF/acyl-PAF and histamine, most probably associated with tumour necrosis factor alpha/cachectin (TNF-alpha), seem to play a central role in the production of the vascular changes required for the extravasation of erythrocytes in the small intestine mucosa.

The role of platelet-activating factor and peptidoleukotrienes in the vascular changes of rat passive anaphylaxis.

1. The role of platelet-activating factor (PAF) and peptidoleukotrienes as putative mediators of some of the vascular changes triggered by antigen was investigated in rats passively sensitized with monoclonal anti-DNP (2,4-dinitrophenyl) IgE. 2. Lethal anaphylaxis with respiratory distress, systemic hypotension, detachment of the intestinal mucosa, leukopenia and extravasation of protein-rich plasma was observed after antigen challenge of rats sensitized with partially purified monoclonal IgE at concentrations of 15 mg protein kg-1. 3. Analysis of the peritoneal fluid obtained after i.v. challenge with DNP-BSA (bovine serum albumin) showed the presence of significant amounts of PAF (101 +/- 8 pg/rat), whereas this mediator was undetectable in control animals. Leukotriene D4 was the predominant peptidoleukotriene that could be recovered after antigen challenge, and showed an extremely high concentration (92 +2- 15 ng/rat) as compared to PAF levels. 4. Extravasation of protein-rich plasma was observed shortly after challenge and reached a maximum at 30 min. Treatment of animals with i.v. PCA 4248 (1-2 mg kg-1) and WEB 2086 (1 mg kg-1), two chemically unrelated compounds which are antagonists of the PAF-receptor, produced a significant reduction of the extravasation of protein-rich plasma. 5. The same degree of protection could be afforded by MK-886, an inhibitor of leukotriene biosynthesis. Combined treatment with WEB 2086 and MK-886 provided greater inhibition of protein-rich plasma extravasation than either compound alone. PCA 4248 was also found to inhibit in a dose-dependent manner the systemic hypotension observed upon DNP-BSA challenge.6. These data indicate that the lipid mediators PAF and peptidoleukotrienes are major effectors of the vascular disturbances observed in rat passive IgE-mediated anaphylaxis.

Nodular fibrosis of the lung in diabetes mellitus.

The target organs in diabetes mellitus include the kidneys, the eyes and the small vessels. In these organs some specific histopathological changes have been described but there are few reports of histopathoogical changes in the lung in diabetic patients. Several reports describe abnormal pulmonary function in diabetic patients and consider these abnormalities to be due to histopahtological changes found in the pulmonary vessels. We have studied the histopathological changes in the diabetic lung comparing the findings in the autopsies of 61 diabetic and 50 non-diabetic patients. Statistically significant differences in the incidence of chronic obstructive lung disease and pulmonary haemorrhage exist. There are no differences in the incidence of fibrosis of the alveolar walls or intimal and medial thickening of small vessels, changes associated with diabetes according to the literature. We have found a specific type of nodular fibrosis not previously reported which we believe to be typical of diabetes.

Congenital segmental dermal melanocytosis in an adult.

BACKGROUND: Dermal melanocytosis is characterized by the presence of melanocytes in the dermis. There are several morphologic forms, such as the blue nevus, the mongolian spot, the nevus of Ota, and the nevus of Ito. In this article, we report an unusual case of dermal melanocytosis. OBSERVATIONS: A 28-year-old white woman was referred to us, as she had an extensive, speckled gray-blue pigmentation on the right aspect of her trunk that was in a segmental pattern. The lesion had been present at birth. Histologic and ultrastructural examinations revealed sparse, elongated dermal melanocytes. CONCLUSIONS: We comment on the differential diagnosis with classic recognized forms of dermal melanocytosis. We also review other isolated cases of unusual dermal melanocytosis. This is a distinct case, clinically different from previously reported cases in the literature; we propose the term "congenital segmental dermal melanocytosis" to name this case.

Lethal cardiac toxicity after cisplatin and 5-fluorouracil chemotherapy. Report of a case with necropsy study.

This article presents a patient affected with epidermoid carcinoma of the soft palate who developed a dilated myocardiopathy with aortic embolism and fatal left cardiac failure after treatment with cisplatin (100 mg/m2, day 1) and 5-fluorouracil (1 g/m2/day i.v. days 2-6). The postmortem necropsy study showed diffuse interstitial edema and intracytoplasmic vacuolization of myocytes, without inflammatory changes. These findings were interpreted as acute toxic myocardiopathy, probably due to 5-fluorouracil treatment. Although the patient also received cisplatin, metoclopramide, allopurinol, thiethylperazine, and amitriptyline, before the onset of clinical symptoms, these drugs were not considered to play an important role in the production of this cardiopathy because of the dosage, necropsy findings, and lack of previous report.

[Non-Hodgkin's lymphoma with heart disease in patients with AIDS: clinical and echocardiographic aspects]. / Linfoma no hodgkiniano con afectación cardíaca en pacientes con SIDA: aspectos clínicos y ecocardiográficos.

We report two patients with AIDS and non-Hodgkin lymphoma evolving myocardium. Clinical findings were nonspecific, but rapid progression and cardiac dysfunction developed. An echocardiogram showed restrictive pericarditis in both cases. One of them showed mitral insufficiency because of an infiltrated and trapped posterior mitral valve.

[Compensatory reaction of the ascending colon following jejuno-ileal bypass. Experimental study]. / Reacción compensadora del colon ascendente tras el by-pass yeyuno-íleal. Estudio experimental.

The series of physiopathologic consequences and the adaptive response that appears in the residual intestine following intestinal by-pass surgery has been widely studied. The same is not true for the ascending colon. Having demonstrated the adaptive changes this organ undergoes after a massive enterectomy, we carried out the present study to evaluate the compensatory reaction after an intestinal by-pass. A total of 115 Wistar rats weighing 350-550 g were used. Twenty animals made up group 0 (control), 30 underwent intestinal section (group II) and 65 received a jejuno-ileal by-pass (group III), with latero-lateral anastomosis. After weight control was performed the animals were sacrificed at 15, 30, 45 and 60 days, and samples were taken from the ascending colon for optical microscopy (OM), scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). All objective data were quantified and statistical studies carried out. The by-pass animals showed statistically significant ponderal drops (p less than 0.001), an expression of the malabsorption disorder the by-pass produced. Groups 0 (control) and I (IS) showed no macroscopic, microscopic or ultrastructural changes. The by-pass animals, however, manifested colic dilatation with a significant increase in thickness, to the detriment of the muscularis and mucosa, and greater crypt depth with a relative decrease in the number of goblet cells. Enterocytes increased in number and size. These changes were statistically significant in relation to groups 0 and I. The above findings were confirmed ultrastructurally. In the scanning electronic microscopy after 30 days, the colic mucosa had an irregular appearance, with elevations but no foliated appearance.(ABSTRACT TRUNCATED AT 250 WORDS)

18F-FDG PET-CT imaging in the neoadjuvant setting for stages II-III breast cancer: association of loco­regional SUVmax with classical prognostic factors.

AIM: Classical prognostic and predictive factors serve to predict outcome and response to neoadjuvant treatment in stage II and III breast cancer. The purpose is to determine the relation between the SUVmax of the locoregional disease with these classical prognostic factors. METHODS: A prospective study including 43 stage II and III breast cancer patients was performed. In all the patients, two 18F-FDG PET-CT studies were performed before and after neoadjuvant chemotherapy. After this treatment, surgery and adjuvant treatment were carried out. To combine the information of the locoregional disease, the SUVmax of the lesion (tumor or abnormal lymphnodes) with the highest uptake was used. SUVmax and prognostic factors were studied with the Kruskal-Wallis non-parametric test and with the Mann-Whitney U. RESULTS: A statistically significant association between elevated SUVmax value and absence of estrogen receptors (ER) expression (16 vs.. 10; P<0.019) was found. Locorregional disease with positive HER2 phenotype had a statistically significant SUVmax value greater than Luminal A (estrogen and/or progesterone positive receptors with Ki67<15%) and B (estrogen and/or progesterone positive receptors with Ki67≥to 15%) (13.4 vs. 7.9 and 8.9; P<0.022 and P<0.024, respectively). Triple negative phenotype disease had higher SUVmax than Luminal A and B (15.4; P<0.030 and P<0.038). Positive correlation between the percentage of the Ki67 Proliferation Index and SUVmax (P<0.007) was demonstrated. High grade disease had a higher SUVmax than low grade (P<0.004). CONCLUSION: Locorregional SUVmax is associated to prognostic and predictive factors and reaffirms the utility of PET-CT as a tool in the common clinical practice.

Assignment of tumor subtype by genomic testing and pathologic-based approximations: implications on patient's management and therapy selection.

BACKGROUND: Breast cancer subtypes can be identified by genomic testing or pathology-based approximations. However, these classifications are not equivalent and the clinical relevance of both classifications needs to be fully explored. METHODS: Ninety-four patients were randomized to neoadjuvant single agent doxorubicin or docetaxel. Tumor subtype was assessed by pathology-based classification and by gene expression using the PAM50 plus the claudin-low predictor (CLP). Kappa Cohen's coefficient (κ) was used to test the agreement between methods. Multivariate Cox proportional hazards analyses were used to determine the significance of each methodology in the prediction of prognosis. Likelihood ratio statistics of both classifications were evaluated. RESULTS: The agreement between pathology-based classification and PAM50 was moderate [κ = 0.551, 95 % confidence interval (95 % CI) 0.467-0.641]. Tumor subtype assessed by both classifications were prognostic for overall survival (OS) and relapse-free survival (P < 0.05). However, PAM50 + CLP provided more prognostic information, in terms of OS, than the pathology-based classification (P < 0.05). Patients with triple negative tumors as well as basal-like tumors had worse OS when first treated with doxorubicin (HR = 5.98, 95 % CI 1.25-28.67, and HR = 5.02, 95 % CI 0.96-26.38, respectively). However, claudin-low tumors did not show significant differences in OS according to neoadjuvant treatment branch. Indeed, we found that claudin-low tumors treated with pre-operative doxorubicin had significantly better OS than basal-like tumors treated with neoadjuvant doxorubicin (adjusted HR = 0.16, 95 % CI 0.04-0.69, P = 0.014). CONCLUSIONS: The assignment of tumor subtype can differ depending on the methodology, which might have implications on patient's management and therapy selection.

Agminated blue nevi: case report and review of the literature.

Blue nevi may rarely appear in multiple form and grouped in a circumscribed area, a pattern of arrangement that is more properly designed under the term agminated blue nevi. In this paper a new case with light and ultrastructural studies is described, and the previously reported cases are reviewed. Histologically, there was a characteristic perifollicular arrangement of dermal melanocytes, most of which showed ultrastructurally an extracellular sheath. Agminated blue nevi seem to be benign lesions, but because of their rarity, no definite prognosis can be given.

Role of complement-derived peptides in thrombocytopenia elicited by soluble aggregates of immunoglobulin G in the rat.

The variations in platelet counts upon intravenous challenge with soluble aggregates of IgG were assessed in normal rats. A time- and dose-dependent thrombocytopenia, followed by recovery to preinfusion values after 30 minutes was observed. Rats injected with immune aggregates showed an increase in plasma levels of immunoreactive thromboxane B2, however, this increase was delayed as compared with the peak level of the thrombocytopenia. Previous treatment of rats with either indomethacin or aspirin, inhibited thromboxane B2 release, but did not affect thrombocytopenia. Pretreatment of the animals with BN 52021, a potent antagonist of platelet-activating factor binding to its receptor, also failed to block thrombocytopenia. Complement depletion by prior treatment with cobra venom factor, caused a significant reduction of the thrombocytopenia, whereas DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid, an inhibitor of carboxypeptidase N, potentiated the thrombocytopenia elicited by submaximal doses of either IgG aggregates or a homogeneous preparation of rat anaphylatoxin containing C5a. In addition, rats challenged with doses of IgG aggregates higher than 5 mg/kg showed a massive complement consumption coincident with the onset of thrombocytopenia. "In vitro" aggregation/secretion experiments with rat platelets showed little platelet-stimulating activity either by aggregated IgG through the Fc receptor or through the CR1 receptor. By contrast, a preparation of rat serum anaphylatoxins containing C5a, showed a high platelet-secreting activity. These data suggest that a complement-derived peptide(s), most probably C5a, is one of the effector substances for platelet activation in response to soluble aggregates of IgG.

Clear-cell syringoma. Immunohistochemistry and electron microscopy study.

Clear-cell syringoma is a histologic variant of syringoma that is otherwise clinically indistinguishable from ordinary syringoma. This variant is formed by cells that have pale or clear cytoplasm as a result of glycogen accumulation. There is a high association of clear-cell syringoma and diabetes mellitus. A case of clear-cell syringoma associated with diabetes mellitus is described. Electron microscopic examination revealed that periluminal cells showed intra- and extracytoplasmic multivesicular bodies that may be characteristic of the clear-cell variant. Immunohistochemistry for carcinoembryonic antigen (CEA) showed ordinary syringomas as in the presence of CEA within and surrounding duct-like spaces.

Cutaneous adult myofibroma: a vascular neoplasm.

Infantile myofibromatosis is a distinctive type of fibromatosis that usually develops during the immediate perinatal period. There are variants with solitary and multiple tumors. Lesions confined to the skin, soft tissue, and bone carry a good prognosis, showing spontaneous regression. The prognosis, however, is much less favorable when visceral lesions are present and the outcome may be fatal. Only recently it became obvious that there is an adult counterpart of infantile myofibromatosis, characterized by solitary lesions that have a predilection for involve the dermis and show no tendency to regression, although they have an entirely benign biological behavior. These lesions have been named cutaneous myofibroma or solitary myofibroma of adults. We have studied the clinical, histopathological and immunohistochemical characteristics of 53 examples of cutaneous adult myofibroma. In addition, 2 cases were examined ultrastructurally. The patients were mostly adults with ages ranging from 6-83 years. The lesions presented as solitary, usually painless nodules of variable duration on the skin, usually located on the extremities. Histopathologically, four patterns were identified: nodular or cellular type, multinodular or biphasic type, leiomyoma-like or fascicular type, and vascular type. A correlation between the histopathologic pattern and the lesional age was observed: vascular type of cutaneous adult myofibroma in early lesions, nodular and multinodular lesions in fully developed lesions, and leiomyoma-like or fascicular type in late lesions. Immunohistochemically, the spindle cells were desmin negative, but expressed immunoreactivity for vimentin, pan-smooth muscle actin, and alpha-smooth muscle actin. Ultrastructurally, neoplastic cells showed characteristics of undifferentiated mesenchymal cells with features of fibroblasts, myofibroblasts and pericytes. Primitive vascular formations were seen in the form of irregular clefts between adjoining cells. We conclude that cutaneous adult myofibroma is a little-known benign vascular neoplasm probably derived from myopericytes.

Ultrastructure of the oviductal mucosa of the rat. III. Basal and peg cells.

In an E.M. analysis of the rat oviduct the authors report the morphology of the so-called indifferent basal cells and peg cells. The hallmark of the former are desmosomes and clear cytoplasm; these elements may detach themselves from the basal membrane, migrating towards the lumen and showing prominent ciliogenesis. Peg cells appear to be the morphological image of necrobiotic cells, either ciliatd or secretory.