Factors affecting outcome of patients with impalpable breast cancer detected by breast screening

Factors affecting completeness of excision and outcome, whether conservation or mastectomy, in 152 patients with localized impalpable breast cancer undergoing therapeutic needle-guided wide local excision were assessed by univariate and multivariate analyses using multiple logistic regression. Independent factors related to completeness of excision at the first operation were operator experience (P = 0.0001), and size of the lesion (P = 0.005). Factors related to outcome were operator experience (P = 0.0003), more experienced operators having a higher rate of breast conservation, and tumour size (P = 0.0001), larger lesions being more likely to be treated by mastectomy. Patients initially operated on by the two most experienced surgeons were more than four times less likely to undergo mastectomy than those whose initial wide local excision was performed by a less experienced surgeon.

Plasmin-catalyzed proteolysis in colorectal neoplasia

The expression of different components of the plasminogen activator (PA)/plasmin system was explored in a series of colorectal neoplasia. We have found that urokinase (uPA) and urokinase receptor (uPA-R) gene expression is upregulated in adenomas and carcinomas, and that uPA/uPA-R production is confined to stromal cells in the proximity of epithelial proliferations. In addition, in adenomas, the focal increase in uPA mRNA is not systematically coupled to detectable enzymatic activity, whereas in carcinomas, uPA mRNA accumulation is consistently associated with detectable but variable levels of enzymatic activity. In contrast, in the tumor vasculature, tissue-type plasminogen activator-mediated proteolysis is considerably reduced when compared to normal mucosal and submucosal vessels; this reduction in plasmin formation appears to result from the highly increased production of plasminogen activator inhibitor type 1 by endothelial cells. Our observations demonstrate that colorectal neoplasia are associated with marked alterations in the extracellular proteolytic balance controlled by the PA/plasmin system. They show that contrasting disturbances in plasmin formation take place in distinct stromal compartments but not in epithelial cells, and that these disturbances are maximal during invasive neoplasia. Altogether, our results raise the possibility that alterations in plasmin formation should not be exclusively regarded as promoters of cancer cell invasiveness.

Molecular and ultrastructural analysis of a nonchromosomal variegated mutant. Tomato mitochondrial mutants that cause abnormal leaf development

Mutants were recovered in a population of cybrids formed following protoplast fusion between tomato (Lycopersicon esculentum Mill.) cv UC82 and Lycopersicon pennellii Corr. The cybrids were identified as individuals with recombinant cytoplasmic genomes but only tomato nuclear genomes. The mutants were identified based on two features, a variegated sectoring of light and dark green regions on their leaves, stems, and fruit, and reduced growth in the field. The mutants produced 50% of the shoot fresh weight and 20% of the fruit fresh weight of the parental type, UC82. The variegated sectoring was maternally inherited. The chloroplast genome in the mutants was indistinguishable from the chloroplast genome in UC82, when distribution of restriction endonuclease sites was used as an assay. The mitochondrial genome in the mutants, however, was recombinant, containing genes from UC82 and L. pennellii. Light microscopic analysis of the leaves of the mutants demonstrated an absence of the palisade layer in the variegated sectors. Electron microscopic analysis of these same regions demonstrated an absence of normal inner membranes in the mitochondria of these cells.

Comparison between 201Tl and 99mTc sestamibi uptake during adenosine-induced vasodilation as a function of coronary stenosis severity

BACKGROUND

Myocardial uptake of either 201Tl or 99mTc-sestamibi (sestamibi) is known to plateau at high coronary flow rates. However, few direct comparisons have been made between these tracers to determine what effect differences in the uptake plateau for the two tracers may have on the detection of coronary stenoses of various severities.

METHODS AND RESULTS

Twenty-two dogs were instrumented with flow transducers on the left anterior descending (LAD) and circumflex (LCx) arteries. In 6 nonstenotic dogs, adenosine was infused directly into the LAD, whereas 16 dogs with either critical (n = 7) or mild (n = 9) LAD stenoses received an intravenous infusion. At peak flow, 201Tl (0.5 mCi), sestamibi (5 to 8 mCi), and radiolabeled microspheres were injected simultaneously. Five minutes later, dogs were killed, and ex vivo imaging of heart slices and gamma-well counting of multiple myocardial samples was performed. Neither 201Tl nor sestamibi uptake increased in direct proportion to flow. In the 6 nonstenotic dogs, a fivefold increase in LAD flow increased 201Tl and sestamibi uptake by only 202 +/- 6% and 138 +/- 4%, respectively (P < .0001). In the dogs with critical stenosis, the ratios of stenotic to normal activity by well counting for 201Tl (0.37 +/- 0.05) and sestamibi (0.53 +/- 0.06) underestimated the microsphere-determined flow disparity (0.17 +/- 0.03) (P < .005), but the degree of underestimation was greater for sestamibi (P = .001). Similarly, in the dogs with mild stenosis, the stenotic-to-normal ratio for 201Tl (0.62 +/- 0.04) approximated the flow ratio (0.43 +/- 0.04) better than sestamibi (0.79 +/- 0.03) (P < .0001). Sestamibi defects, however, were visually identifiable on the images of the myocardial slices. By image quantification, sestamibi defect magnitude (LAD-to-LCx count ratio) in the critical stenosis group (0.62 +/- 0.05) was significantly less than in the mild stenosis group (0.80 +/- 0.02) (P < .01).

CONCLUSIONS

Thus, with adenosine-induced hyperemic flow, both 201Tl and sestamibi significantly underestimated the magnitude of the flow disparity between stenotic and normal perfusion beds. The degree of underestimation was greater for sestamibi. The clinical implication of these experimental findings for vasodilator perfusion imaging remains to be determined, since factors such as greater redistribution and scatter with 201Tl could offset its advantages.

Evaluation of novel formulations of 35S- and 33P-labelled nucleotides for in situ hybridization

Radioactive in situ hybridization predominantly utilizes either RNA probes or oligonucleotide probes. The properties of various formulations of [35S]UTP alpha S have been studied with respect to probe labelling and when applied to in situ hybridization. A new formulation has been prepared that combines a high physical concentration with a high specific activity so that, theoretically, predominantly full-length, high-specific-activity primary transcripts are produced. [alpha-33P]UTP can also be used for in situ hybridization and it compares favourably to 35S-labelled probes in terms of resolution and sensitivity. Both radiolabels can also be used to label oligonucleotide probes by a tailing reaction. [35S]dATP alpha S has been reformulated specifically for labelling oligonucleotides. The traditional stabilizer, dithiothreitol, which may cause precipitation within the tailing reaction buffer, has been replaced with an alternative stabilizer that avoids this problem while maintaining the stability of the nucleotide.

Fluorescein as a label for non-radioactive in situ hybridization

Non-radioactive techniques can be applied to many in situ hybridization (ISH) applications, and a number of non-radioactive labels for this process have been reported. However, these labels have some inherent problems in terms of both background and signal-to-noise values. We have sought to address these issues by searching for an alternative label that has the following features: efficient incorporation into probes, non-endogenous to biological systems, the availability of a high-affinity, high-specificity antibody. Fluorescein has been shown to meet these requirements. In addition, due to the fluorescent nature of the label, it has been possible to design a rapid, non-radioactive labelling assay and also to view in situ hybridization results by direct fluorescence in certain ISH applications. The hybridization kinetics have been investigated. Significant improvements have been made to the hybridization buffer leading to reduced background and increased rates of hybridization when compared to traditional hybridization buffers.

Transplantation strategies for the analysis of brain development and repair

Fetal tissue provides the best functional restoration in transplantation therapies for neurodegenerative diseases. Lineage analysis using in vivo cell marking methods shows that a multipotential cell gives rise to different neuronal types in the mammalian central nervous system. Culture methods that allow this cell to be expanded in vitro would provide important additional tools in the development of brain transplant therapies. The stem cells of the mammalian central nervous system express nestin, an intermediate filament protein that is abundant in neuronal and glial precursors but not present in the normal adult brain. Primary and immortal cultures of nestin-positive cells have been established and the differentiation of these cells analyzed both in vitro and by transplantation into the developing central nervous system. We have expanded neuronal precursor cells in vitro as both primary and immortal cells. Following implantation into the hippocampus, neurons derived from cultured stem cells are integrated into the host tissue. These findings encourage re-examination of the use of cultured cells in therapeutic transplants to the adult brain. In addition to increasing cell number, the period of culture may also permit genetic manipulation to define mechanisms of neuronal function and to enhance the therapeutic utility of transplanted cells.

E2 and NS5: new antigens for detection of hepatitis C virus antibodies

The value of two new hepatitis C virus (HCV) antigens for detection of HCV antibodies was studied. These two recombinant antigens were derived from the nonstructural-5 (NS5) and envelope-2 (E2) region of the HCV genome. In a panel of 33 HCV-RNA positive samples with indeterminate Riba-2 confirmatory test results, 29 samples (88%) showed additional antibody reactivity against E2 and 12 samples (36%) showed additional reactivity against NS5. Among 39 HCV-RNA negative, Riba-2 indeterminate donor samples, no additional E2 or NS5 reactivity was found in 34 samples (87%); while 5 samples (13%) showed additional reactivity against NS5 and/or E2. E2 reactivity thus resolved the majority of hitherto indeterminate samples. In serial samples from nine posttransfusion hepatitis C patients, NS5 and E2 antibodies did not appear earlier than classical HCV antibodies. However, E2 antibodies eventually appeared in all nine patients. The recombinant E2 might be a candidate antigen for future HCV antibody assays.

Structural similarity between the p17 matrix protein of HIV-1 and interferon-gamma

The human immunodeficiency virus (HIV) matrix protein, p17, forms the outer shell of the core of the virus, lining the inner surface of the viral membrane. The protein has several key functions. It orchestrates viral assembly via targeting signals that direct the gag precursor polyprotein, p55, to the host cell membrane and it interacts with the transmembrane protein, gp41, to retain the env-encoded proteins in the virus. In addition, p17 contains a nuclear localization signal that directs the preintegration complex to the nucleus of infected cells. This permits the virus to infect productively non-dividing cells, a distinguishing feature of HIV and other lentiviruses. We have determined the solution structure of p17 by nuclear magnetic resonance (NMR) with a root-mean square deviation for the backbone of the well-defined regions of 0.9 A. It consists of four helices connected by short loops and an irregular, mixed beta-sheet which provides a positively charged surface for interaction with the inner layer of the membrane. The helical topology is unusual; the Brookhaven protein database contains only one similar structure, that of the immune modulator interferon-gamma.

Alterations in major histocompatibility complex association of myocarditis induced by coxsackievirus B3 mutants selected with monoclonal antibodies to group A streptococci

Three monoclonal antibodies (mAbs), 49.8.9, 36.2.2, and 54.2.8, made to the group A streptococcus M5 serotype identify crossreactive epitopes in cardiac tissues and also neutralize a highly myocarditic variant of coxsackievirus B3 (H3). Mutants of H3 were selected with these mAbs and evaluated for pathogenicity compared with the wild-type virus. H3 and the mutant variants selected with mAbs 36.2.2 (H3-36) and 54.2.8 (H3-54) induced severe myocarditis in DBA/2 (H-2d) and A/J (H-2a) male mice, whereas CBA (H-2k) mice were disease resistant. The virus variant isolated with mAb 49.8.9 (H3-49) was strikingly different and caused disease in CBA and A/J mice but not in DBA/2 animals, suggesting that the major histocompatibility complex association of the disease had been altered. This hypothesis was confirmed by using B10 congenic mice. In addition, T lymphocytes from the H3 and H3-49 virus-infected mice responded to distinctly different peptides in the streptococcal M protein, suggesting that certain epitopes of infectious agents which are shared with host tissues may be critical in determining disease susceptibility in genetically distinct individuals.

Tyrosine phosphorylation of pp125FAK in platelets requires coordinated signaling through integrin and agonist receptors

FAK is a focal adhesion kinase that is phosphorylated on tyrosine in activated platelets. Induction of FAK phosphorylation requires both fibrinogen binding to integrin alpha IIb beta 3 and post-occupancy events during agonist-induced platelet aggregation or platelet spreading on a fibrinogen matrix. To identify the signaling pathways necessary for tyrosine phosphorylation of FAK, we have examined the conditions that stimulate or inhibit this phosphorylation in platelets in which fibrinogen binding to alpha IIb beta 3 and platelet aggregation were induced directly with an anti-beta 3 Fab fragment (anti-LIBS6). Apyrase was added to prevent effects of the endogenous platelet agonist, ADP. Under these conditions, neither fibrinogen binding nor primary platelet aggregation was sufficient to induce FAK phosphorylation, suggesting that a second "costimulatory" event was required. Indeed, when epinephrine was added with fibrinogen and anti-LIBS6, large platelet aggregates formed and FAK phosphorylation occurred. This response was prevented by blockade of cyclooxygenase with indomethacin or thromboxane A2 receptors with SQ 30,741. A stable thromboxane A2 analogue (U46619) could substitute for epinephrine as the costimulus. Epinephrine costimulation of FAK phosphorylation was also prevented by chelation of intracellular Ca2+ with BAPTA or selective inhibition of protein kinase C (PKC) with bisindolylmaleimide, indicating that Ca2+ and PKC are necessary for FAK phosphorylation under these conditions. Epinephrine also promoted FAK phosphorylation and adhesive spreading of apyrase-treated platelets on a fibrinogen matrix. Cytochalasin D, an inhibitor of actin polymerization, blocked FAK phosphorylation under all these conditions. Thus, tyrosine phosphorylation of FAK in platelets requires coordinated signaling through occupied integrin and agonist receptors. These separate pathways may converge to increase free Ca2+ and activate PKC and thus promote the cytoskeletal reorganization required for activation of FAK.

Secondary structure of fibronectin type 1 and epidermal growth factor modules from tissue-type plasminogen activator by nuclear magnetic resonance

A segment of human tissue-type plasminogen activator (t-PA) corresponding to the fibronectin type 1 (F1) and epidermal growth factor-like (G) pair of modules, residues 1-91, has been produced as a recombinant protein in Saccharomyces cerevisiae, with a single conservative Cys to Ser substitution. The sequence-specific assignment of the 1H and 15N nuclear magnetic resonances from the pair of modules has been completed using 2D 1H nuclear magnetic resonance (NMR) spectra in conjunction with 3D, 15N-edited, 1H and 2D 15N-1H NMR spectra. Slowly exchanging amide protons have been identified, and estimates of a number of backbone 3JNH-C alpha H coupling constants were obtained by line-shape-fitting. The secondary structure of the F1 module in the pair closely matches that previously determined for the isolated F1 module from t-PA, and that of the G module conforms to the "consensus" G module structure determined previously from several isolated G modules. In the module pair, the residues linking the two modules appear to form an extended beta-strand, the carboxy-terminal end of which makes up a third strand of the major beta-sheet of the G module. The intermodule interface is defined by NOEs between residues in the ranges 22-24 in the F1 module and 65-72 in the G module. The NMR data indicate that there is little or no reorientation of the two modules with respect to one another but rather that they combine with a fixed hydrophobic contact dominated by the side chain of leucine-22.

An audit of utilisation of Holter tape facilities at Glasgow Royal Infirmary

Holter tape analysis is widely used to both confirm and exclude the presence of significant arrhythmias. We have studied the utilisation of the Holter service at Glasgow Royal Infirmary over a period of 6 months. During this period 305 x 24 hour Holter tapes were recorded. Out patient referrals generated 95% of these requests with only 5% of requests for in patient recordings. The median delay from request date to dispatch to the referring doctor was 14 days. No arrhythmia was detected in 77% and only 3% had a detectable symptomatic significant arrhythmia. The recording was felt to demonstrate the presence of a relevant arrhythmia in 17% of cases and to help exclude a possible arrhythmia in 61%. The capital cost per tape was 20.82 Pounds. In conclusion Holter monitoring is an inexpensive way of analysing the heart rhythm over an extended period which is probably underused.

Independent regulatory elements in the nestin gene direct transgene expression to neural stem cells or muscle precursors

Changes in intermediate filament gene expression occur at key steps in the differentiation of cell types in the mammalian CNS. Neuroepithelial stem cells express the intermediate filament protein nestin and down-regulate it sharply at the transition from proliferating stem cell to postmitotic neuron. Nestin is also expressed in muscle precursors but not in mature muscle cells. We show here that in transgenic mice, independent cell type-specific elements in the first and second introns of the nestin gene consistently direct reporter gene expression to developing muscle and neural precursors, respectively. The second intron contains an enhancer that functions in CNS stem cells, suggesting that there may be a single transcriptional mechanism regulating the CNS stem cell state. This enhancer is much less active in the PNS. The identification of these elements facilitates analysis of mechanisms controlling the switch in gene expression that occurs when muscle and brain precursors terminally differentiate.

Immortalized stem cells from the central nervous system

A remarkable feature of the early development of the mammalian central nervous system (CNS) is the precise and rapid generation of large numbers of many different neuronal types [1]. We have identified the major neuronal precursor cell and shown that this cell can be immortalized by oncogenes. The immortal precursor cell can be grown in culture and can differentiate when transplanted into the developing brain. The implanted neurons are integrated into the synaptic circuitry of the host brain. These results suggest that implanting cultured precursor cells will provide a powerful strategy to uncover the signals that control the differentiation of this multipotential cell into the many cell types of the adult brain.

Effect of concurrent acute infection with hepatitis C virus on acute hepatitis B virus infection

OBJECTIVE

To investigate the possible interference with acute hepatitis B virus infection by co-infection with hepatitis C virus.

DESIGN

Analysis of stored sera collected for transfusion transmitted viruses study in 1970s.

SETTING

Four major medical centres in the United States.

PATIENTS

12 recipients of blood infected with hepatitis B virus.

MAIN OUTCOME MEASURES

In 1970s, presence of antibodies in hepatitis B virus and raised serum alanine aminotransferase concentration; detection of antibodies to hepatitis C virus with new enzyme linked immunoassays.

RESULTS

Five of the 12 patients were coinfected with hepatitis C virus. Hepatitis B surface antigen was first detected at day 59 in patients infected with hepatitis B virus alone and at day 97 in those coinfected with hepatitis C virus (p = 0.01); median durations of antigenaemia were 83 and 21 days respectively (p = 0.05), and the antigen concentration was lower in the coinfected patients. Alanine aminotransferase patterns were uniphasic when hepatitis B virus infection occurred alone (range 479-2465 IU/l) and biphasic in patients with combined acute infection (no value > 380 IU/l; p = 0.0025). Four coinfected recipients developed chronic hepatitis C virus infection. The fifth patient was followed for only four months.

CONCLUSIONS

Acute coinfection with hepatitis C virus and hepatitis B virus inhibits hepatitis B virus infection in humans, and onset of hepatitis B may reduce the severity of hepatitis C virus infection but not frequency of chronicity. Alanine aminotransferase concentration showed a biphasic pattern in dual infection.

Types of benzodiazepines abused by chemically dependent inpatients

Records of inpatients (N = 1,483) over a three-year period at an addiction treatment center were evaluated for the presence of benzodiazepine (BZ) dependence (N = 136). The preferred BZ for 43% of the subjects was diazepam, and alprazolam for 14% of subjects. Chlordiazepoxide, lorazepam, and clorazepate were each the preferred BZ for 4% of patients. Cocaine and opioid abusers were six times more likely to abuse diazepam than any other BZ. Alprazolam patients required a significantly longer period of detoxification than diazepam patients. Four percent of BZ-dependent patients (N = 6) abused BZs only and had no other substance abuse history.

Variations in therapeutic interventions for Cambodian and Chilean refugee survivors of torture and trauma: a pilot study

The treatment of refugee survivors of torture and trauma has attracted increasing clinical attention. The present study surveyed therapists concerning the emphasis that was placed on disclosure of previous traumatic experiences in therapy with refugees from Chile and Cambodia. Significant differences were found between the two groups with trauma story discussion being judged by therapists to be more important to treatment outcome in Chilean patients. The problem of potential therapist bias limits definitive conclusions, however we suggest that differences in cultural preparedness for psychotherapy aimed at uncovering previous traumatic experiences may be the main reason for variations in styles of therapy offered to these distinctive ethnic groups. Other possible explanations are differences in diagnostic profiles and types of previous traumatic experiences.

Trypanosoma cruzi trypanothione reductase. Crystallization, unit cell dimensions and structure solution

We have reproducibly crystallized recombinant trypanothione reductase from Trypanosoma cruzi. Yellow tetragonal crystals in the shape of elongated prisms have unit cell dimensions of a = 92.8 A, c = 156.6 A, Laue symmetry of 4/m and are suitable for a detailed structural analysis. Diffraction data to 2.7 A resolution have been recorded using synchrotron radiation at the Daresbury laboratory. The structure has been solved by molecular replacement calculations using this synchrotron data and our previously determined Crithidia fasciculata enzyme structure as a search model. The space group has been identified as P4(3) with a homodimer of approximate molecular mass of 108 kDa in the asymmetric unit. Diffraction beyond 2.5 A has been recorded when large freshly grown crystals are exposed to X-rays. Refinement of the structure is in progress.

Identification of connective tissue gene transcripts in freshly isolated parenchymal, endothelial, Kupffer and fat-storing cells by northern hybridization analysis

The aim of the present study was to identify the cell types that express collagen alpha 1(I), alpha 1(III) and alpha 1(IV), fibronectin and laminin B1 genes in normal rat liver. Parenchymal, sinusoidal endothelial, Kupffer and fat-storing (Ito) cells were isolated and purified. Total RNA of the freshly isolated cells was subjected to Northern hybridization analysis. We also compared the steady state levels of specific mRNAs in freshly isolated fat-storing cells to the levels in myofibroblast-like cells obtained from purified fat-storing cells cultured for two passages. The average purity of each cell preparation, and the percentage of contaminating cells, were determined by transmission electron microscopy and by examining the presence of vitamin A-autofluorescent cells. Fibronectin and collagen alpha 1(III) mRNAs were detected in total RNA of purified parenchymal cells. In poly(A)+ enriched RNA, small amounts of collagen alpha 1(I) mRNA were also present. In total RNA of freshly isolated fat-storing cells, collagen alpha 1(III), alpha 1(IV), and laminin B1 transcripts were found, whereas collagen alpha 1(I) and fibronectin mRNAs were not detected. Cultured fat-storing cells, however, did contain high levels of collagen alpha 1(I) and fibronectin mRNAs. The molecular size of the latter transcript was larger than the fibronectin transcript found in parenchymal cells and the whole liver. Endothelial cells contained small amounts of alpha 1(IV) mRNA. Kupffer cells did not contain the investigated transcripts. We conclude that normal parenchymal, fat-storing and endothelial cells each express a typical pattern of connective tissue molecules. When fat-storing cells are allowed to differentiate into myofibroblast-like cells, they express high levels of collagen alpha 1(I) and fibronectin mRNAs, in addition to collagen alpha 1(III) and alpha 1(IV), and laminin B1 chain mRNAs.