Expression of the genome of potato leafroll virus: readthrough of the coat protein termination codon in vivo

An antiserum was raised against a fusion protein containing part of the 56K polypeptide (P5) encoded by the open reading frame (ORF) at the 3' end of the genome of potato leafroll virus (PLRV). This antiserum reacted specifically with 80K and 90K polypeptides in PLRV-infected protoplasts, with a 90K polypeptide in infected potato tissue and with a 53K polypeptide in protein extracted from purified particles of PLRV. Monoclonal antibodies raised against purified PLRV particles also reacted with these polypeptides, as well as with the 23K coat protein. Virus particles partially purified from infected protoplasts contained some 90K polypeptide as well as the major 23K coat protein. The ORFs of the 23K coat protein and P5 are contiguous and in frame. The results suggest that the P5 polypeptide of PLRV occurs in infected cells as part of a readthrough protein comprising the 23K coat protein joined to the P5 amino acid sequence. Moreover the readthrough protein can be assembled into virus particles as a minor component together with the main 23K component. The P5 protein may thus contribute to properties of PLRV determined by its virus particle surface.

Anxiety levels and cancer fear in patients admitted for elective operations

Patients who are to have elective operations project varying degrees of anxiety, and many spontaneously express fear (without basis) that their operation involves a diagnosis of malignancy. To measure total, covert, and overt anxiety objectively, we gave the Institute for Personality and Ability Testing anxiety test to 125 consecutive patients admitted for elective general surgical procedures. A simple survey of cancer fear was also completed. Chi-square and Fisher's exact test were used to compare categoric data, and linear regression and analysis of variance were used where appropriate. Total anxiety scores were in the upper quartile compared to the general population. Scores indicating fear of cancer were elevated in 75% of patients who had no history of or reason to suspect malignancy. Covert anxiety scores correlated with cancer fear scores, and both significantly decreased as age increased (P less than .05). Also, as age increased, the cancer fear scores decreased (P less than .002). Obese patients had higher scores of cancer fear than all other patients (P less than .0001).

Effect of ATP on actin filament stiffness

Actin is an adenine nucleotide-binding protein and an ATPase. The bound adenine nucleotide stabilizes the protein against denaturation and the ATPase activity, although not required for actin polymerization, affects the kinetics of this assembly Here we provide evidence for another effect of adenine nucleotides. We find that actin filaments made from ATP-containing monomers, the ATPase activity of which hydrolyses ATP to ADP following polymerization, are stiff rods, whereas filaments prepared from ADP-monomers are flexible. ATP exchanges with ADP in such filaments and stiffens them. Because both kinds of actin filaments contain mainly ADP, we suggest the alignment of actin monomers in filaments that have bound and hydrolysed ATP traps them conformationally and stores elastic energy. This energy would be available for release by actin-binding proteins that transduce force or sever actin filaments. These data support earlier proposals that actin is not merely a passive cable, but has an active mechanochemical role in cell function.

Antigen presentation by keratinocytes induces tolerance in human T cells

Antigen recognition by interleukin 2 (IL 2)-producing T lymphocytes can lead to two distinct outcomes, depending on the nature of the antigen-presenting cell. Recognition of antigen presented by specialized antigen-presenting cells leads to T cell activation; in contrast, antigen presentation by cells which lack "accessory function" can lead to a state of specific nonresponsiveness, which is characterized by a failure to produce IL 2. We have shown in this study that co-culture of an HLA-DR1/4-restricted, influenza hemagglutinin-specific T cell clone with a specific peptide presented by interferon-gamma-induced DR4-expressing keratinocytes causes tolerance induction. This effect was DR restricted, in that it required pre-incubation of the T cell clone with keratinocytes expressing an appropriate DR type (DR4Dw14). The induction of T cell tolerance was also antigen specific; no inhibition resulted from pre-incubation of the clone with an irrelevant peptide. Furthermore cell to cell contact appeared to be necessary, and the addition of supernatant from interferon-gamma-induced keratinocytes did not cause any inhibition. This phenomenon may have relevance to the immunogenicity of transplanted cultured keratinocytes and to the effects of major histocompatibility complex class II induction on non-bone marrow-derived cells. Presentation of tissue-specific autoantigens by cells such as keratinocytes may provide a mechanism of avoiding, rather than stimulating, autoimmune reactions in the context of a local inflammatory response.

Clinical features and molecular analysis of the alpha thalassemia/mental retardation syndromes. I. Cases due to deletions involving chromosome band 16p13.3

We describe eight patients who have alpha thalassemia which cannot be accounted for by the Mendelian inheritance of abnormal alpha globin genes. Apart from the hematologic abnormality, the other universal clinical finding is mild to moderate mental handicap; there is also a broad spectrum of associated dysmorphic features. Initial analysis of the alpha globin gene complex (which maps to chromosome band 16p13.3), demonstrated that the alpha thalassemia results from failure of the patient to inherit an alpha globin allele from one of the parents. Using a combined molecular and cytogenetic approach, we have extended this analysis to show that all of these patients have 16p deletions which are variable in extent but limited to the terminal band 16p13.3; in at least four cases the deletion results from unbalanced chromosome translocation, and hence aneuploidy of a second chromosome is also present. The relatively nonspecific clinical phenotype contrasts with the other currently known microdeletion syndromes; this may reflect ascertainment bias in the recognition of such syndromes. This work represents the first step in the characterization of a new microdeletion syndrome that is probably underdiagnosed at present.

Resemblance of actin-binding protein/actin gels to covalently crosslinked networks

The maintainance of the shape of cells is often due to their surface elasticity, which arises mainly from an actin-rich cytoplasmic cortex. On locomotion, phagocytosis or fission, however, these cells become partially fluid-like. The finding of proteins that can bind to actin and control the assembly of, or crosslink, actin filaments, and of intracellular messages that regulate the activities of some of these actin-binding proteins, indicates that such 'gel-sol' transformations result from the rearrangement of cortical actin-rich networks. Alternatively, on the basis of a study of the mechanical properties of mixtures of actin filaments and an Acanthamoeba actin-binding protein, alpha-actinin, it has been proposed that these transformations can be accounted for by rapid exchange of crosslinks between actin filaments: the cortical network would be solid when the deformation rate is greater than the rate of crosslink exchange, but would deform or 'creep' when deformation is slow enough to permit crosslinker molecules to rearrange. Here we report, however, that mixtures of actin filaments and actin-binding protein (ABP), an actin crosslinking protein of many higher eukaryotes, form gels rheologically equivalent to covalently crosslinked networks. These gels do not creep in response to applied stress on a time scale compatible with most cell-surface movements. These findings support a more complex and controlled mechanism underlying the dynamic mechanical properties of cortical cytoplasm, and can explain why cells do not collapse under the constant shear forces that often exist in tissues.

Identification of a locus which shows no genetic recombination with the autosomal dominant polycystic kidney disease gene on chromosome 16

The major site for mutations leading to autosomal dominant polycystic kidney disease (ADPKD) is at the PKD1 locus, previously mapped to 16p13. Three additional probes have now been mapped within an existing array of genetic markers flanking this locus. One of these, CMM65b (D16S84), shows no recombination with PKD1 in 201 informative meioses. The others, Fr3-42 (D16S21) and EKMDA2 (D16S83), are shown to be the closest telomeric flanking markers. Somatic cell hybrids containing derivative chromosome 16s were used to construct a physical map of the region. Cosmid overlap cloning of the D16S84 region allowed a t(16;1) translocation breakpoint to be mapped at the molecular level, orientating the extended D16S84 locus with respect to the chromosome. The new markers and physical map described here provide an improved framework for attempts to clone the PKD1 region and to identify polycystic kidney disease mutations.

The role of the psychiatric/mental health nurse clinical specialist in an adolescent coping skills group

The psychiatric/mental health nurse clinical specialist is a professional who brings unique skills to the area of mental health prevention. Adolescents are an at-risk population in need of preventive mental health services. This article describes the unique features of a nurse-led adolescent prevention program. A specific Adolescent Coping Skills Group format, which uses the skills of the master's prepared psychiatric nurse, is presented.

Characterization of a transferrin-independent uptake system for iron in HeLa cells

HeLa cells incubated in serum-free medium accumulated 59Fe ("non-transferrin iron") when incubated with either 59Fe-citrate, 59Fe-nitrilotriacetate, or 59Fe dissolved in Tricine ascorbate. Accumulation of iron was time-, concentration-, and Ca2+-dependent and was saturable. Uptake of non-transferrin (non-Tf) iron was transferrin-independent because of the fact that uptake occurred at pH 5.5, a pH at which transferrin binds iron poorly and at which transferrin is not internalized by cells. Uptake of non-Tf iron was less affected than uptake of transferrin iron by 1) exposure of cells to trypsin, a maneuver that cleaves Tf receptors, or 2) incubation of cells with phenylarsine oxide, an agent that inhibits both fluid- and receptor-mediated internalization. After exposure of cells to non-Tf iron at 37 degrees C, most of the cell-associated radioactivity was recovered in heme and ferritin, demonstrating that iron gained access to intracellular compartments and was not simply adsorbed to the cell surface. Uptake of non-Tf iron could be partially blocked by Cu2+ in a dose-dependent manner, while the accumulation of transferrin-bound iron was unaffected by Cu2+. Other transition metals, such as Zn2+, Cd2+, and Mn2+ were able to inhibit the uptake of non-Tf iron to different degrees. The accumulation of 109Cd was inhibited by incubation of cells with non-Tf iron, Cu2+, or Mn2+. The extent of inhibition was concentration- and metal-dependent. A number of cultured cell lines including HeLa, human skin fibroblasts, and Chinese hamster ovary cells demonstrated uptake of non-Tf iron and 109Cd. Additionally, an endosome acidification mutant of Chinese hamster ovary cells, which exhibited an increase in non-Tf iron uptake, also exhibited an increase in the uptake of Cd2+. These observations suggest that the characteristics of the non-Tf iron transport system in HeLa cells are similar if not identical to those reported for perfused rat liver (Wright, T. L., Brissot, P., Ma, W.-L., and Weisiger, P. A. (1986) J. Biol. Chem. 261, 10909-10914) and suggest the existence of a family of transition metal transport systems, each with a different metal specificity.

Edinburgh trial of screening for breast cancer: mortality at seven years

Between 1979 and 1981, 45,130 women in Edinburgh aged 45-64 were entered into a randomised trial of breast cancer screening by mammography and clinical examination. The initial attendance rate was 61% but this varied according to age and socioeconomic status and decreased over succeeding years. The cancer detection rate was 6.2 per 1000 women attending at the first visit; the rate fell to around 3 per 1000 in the years when mammography was routinely repeated and to around 1 per 1000 at the intervening visits with clinical examination alone as the screening method. After 7 years of follow-up the mortality reduction achieved was 17% (relative risk = 0.83, 95% CI 0.58-1.18), which was not statistically significant, even when corrected for socioeconomic status. In women aged 50 years and over a mortality reduction of 20% was achieved.

Detection of breakpoints in submicroscopic chromosomal translocation, illustrating an important mechanism for genetic disease

A 3-year-old boy presented with alpha-thalassaemia, dysmorphic features, and mental handicap. His younger sister is also mentally retarded, but haematologically normal. High resolution cytogenetic analysis revealed a normal karyotype in all family members. However, a combination of DNA analysis and in situ hybridisation demonstrated that the mother has a previously unsuspected balanced reciprocal translocation between the tips of the short arms of chromosomes 1 and 16, and that the alpha-globin gene complex (which maps to the tip of chromosome 16) is included in the translocated segment. Both of her children have inherited one of the translocation chromosomes in an unbalanced fashion: the boy has the derived chromosome 16, and therefore has alpha-thalassaemia, whilst the girl has the derived chromosome 1. Such cytogenetically invisible subtelomeric translocations are probably an important and hitherto unrecognised cause of genetic disease.

Influence of cancer histology on the success of fine needle aspiration of the breast

Fine needle aspiration (FNA) cytology carried out on 1318 primary breast cancers from 1980 to 1986 inclusive showed that 198 were well recognised, histological special types. These included medullary, mucoid, tubular, cribriform and lobular invasive cancers, and non-invasive cancers. Excluding these special histological types, the overall number successfully identified (malignant plus suspicious) by fine needle aspiration was 940 (84%), although in only 820 (73%) was malignancy definitely diagnosed. The results for the special types were variable, the mucoid and medullary cancers being consistently identified while the other types were not. For tubular and cribriform, lobular and non-invasive ductal cancers a malignant diagnosis was made in 30% to 40% of cases, although inclusion of suspicious results gave identification figures of 60% to 70%. Particular cytological patterns are characteristic of some special histological cancer types but lesion cellularity, size, and physical definition are all intrinsic factors influencing success of FNA diagnosis. About 10% of all primary breast cancers seem to have certain histological properties which further reduce the success of fine needle aspiration.

Molecular study of the T cell repertoire in family contacts and patients with leprosy

The specificity of lymphocyte proliferative responses of 22 family contacts and 7 patients with leprosy were analyzed using Ag fractions from soluble extracts of Mycobacterium leprae and Mycobacterium tuberculosis. Fractions 10-100 kDa m.w. from each extract were separated by SDS-polyacrylamide gel electrophoresis, electroblotted to nitrocellulose membrane and solubilized for use in lymphocyte culture. The main immunogenic fractions for both contacts and patients had m.w. of 12,000 to 22,000, 35,000 to 40,000, and 65,000. Determinants which were either distinct or shared by the two extracts were active in each of the immunogenic fractions. Lymphocyte proliferation following stimulation with separated Ag was found also in five subjects who failed to respond to the whole soluble extracts. Stimulatory synthetic peptides were identified for the 65 kDa protein Ag. This technique has permitted the screening of the T cell immune repertoire for the identification of the immunodominant Ag which merit further purification and molecular characterization.

Molecular study of the T cell repertoire in family contacts and patients with leprosy

The specificity of lymphocyte proliferative responses of 22 family contacts and 7 patients with leprosy were analyzed using Ag fractions from soluble extracts of Mycobacterium leprae and Mycobacterium tuberculosis. Fractions 10-100 kDa m.w. from each extract were separated by SDS-polyacrylamide gel electrophoresis, electroblotted to nitrocellulose membrane and solubilized for use in lymphocyte culture. The main immunogenic fractions for both contacts and patients had m.w. of 12,000 to 22,000, 35,000 to 40,000, and 65,000. Determinants which were either distinct or shared by the two extracts were active in each of the immunogenic fractions. Lymphocyte proliferation following stimulation with separated Ag was found also in five subjects who failed to respond to the whole soluble extracts. Stimulatory synthetic peptides were identified for the 65 kDa protein Ag. This technique has permitted the screening of the T cell immune repertoire for the identification of the immunodominant Ag which merit further purification and molecular characterization.

Clonal analysis of the cellular immune response to the house dust mite Dermatophagoides farinae

A panel of human CD4+ T cell clones specific for the house dust mite was isolated from an atopic individual with perennial rhinitis. Soluble antigen specificity was defined using proliferation assays and subsequently the antigenic determinants recognized by some of these clones were mapped using nitrocellulose immunoblots of fractionated Dermatophagoides spp. Both cross-reactive and species-specific T cell clones were identified and in some instances their specificity could be mapped to the serologically defined Der f I, Der p I and Der f II allergens. In comparison, the serum antibody response showed additional specificity for Der f III. The antigen recognition by six of these clones was found to be restricted by HLA-DR gene products.

Functional evidence for the recognition of endogenous peptides by autoreactive T cell clones

The fine specificity of two human T cell clones responding to autologous HLA-DR1 expressing antigen-presenting cells (APC) in the absence of nominal antigen has been investigated using Epstein-Barr virus-transformed B cells (BCL) of known DR beta 1 domain sequence. It was found that responsiveness was markedly affected by changes in a limited number of residues in this domain. Substitution of the DR1 beta sequence at one residue, position 74, even conservatively, was found to be particularly significant. Located on the beta 1 domain alpha-helix, this residue is predicted to point into the antigen-binding groove and is therefore unlikely to make contact with the T cell receptor. This finding suggests that these T cells are specific for a bound endogenous peptide within the autologous major histocompatibility (MHC) binding groove. The autospecific T cell clones also responded to murine L cell transfectants expressing DR alpha DR1 beta as well as to transfectants expressing the mouse/human hybrid MHC molecule I-E alpha DR1 beta but not to the reciprocal combination DR alpha I-E beta, thus confirming the importance of the beta 1 domain to T cell recognition. In contrast to the autocytotoxicity observed with BCL, cytolysis of the murine L cells expressing the HLA-DR1 molecule was slight and only found at high effector-target ratios. In addition, although fixation enhanced the recognition of BCL, capacity of the murine L cells bearing the HLA-DR1 molecule to stimulate T cell clone proliferation was markedly reduced by aldehyde fixation. When taken together, these results suggest that the endogenous peptides recognized by these autoreactive T cells are of human origin.

Structural and functional studies of HLA-DR restricted antigen recognition by human helper T lymphocyte clones by using transfected murine cell lines

Murine L cells expressing the products of transfected HLA-DR1 genes functioned as APC for two influenza-specific, human Th cell clones with comparable efficiency to a DR1-expressing human lymphoblastoid cell line. In order to investigate the restriction specificity of the two Th clones, a transfectant expressing the species-mismatched MHC class II dimer DR1:I-E was tested as an APC. Both T cells showed no loss of Ag sensitivity due to substitution of the murine chain. One of the Th clones, TLC 72, showed even greater degeneracy by responding to Ag in the context of I-Ek. Taking into account the lower level of MHC class II expression on the I-Ek transfectant, there is remarkably little loss of efficiency of Ag-induced T cell activation due to the substitution of I-E for DR as restriction element. The Ag-specific responses of both clones were inhibited by anti-CD4 antibody when DR-transfected L cells or human lymphoblastoid cells were used as APC. This inhibition was also seen when Ag was presented to TLC72 by the I-Ek-expressing transfectant. Whether this inhibition is the result of negative signaling or of blocking an interaction between human CD4 and I-Ek is discussed. Similarly the inhibitory effects of mAb against the T cell accessory molecule LFA/1 were the same for both clones when either the transfectants or the lymphoblastoid cell line were used as APC, suggesting that L cells may express a molecule that is capable of acting as a ligand for human LFA/1. The results presented here further illustrate the value of transfectants in analyzing T cell recognition and accessory cell requirements. The patterns of degeneracy of MHC restriction exhibited by these clones provides a platform for a more detailed analysis of key residues involved in MHC class II-restricted T cell Ag recognition.

Structural and functional studies of HLA-DR restricted antigen recognition by human helper T lymphocyte clones by using transfected murine cell lines

Murine L cells expressing the products of transfected HLA-DR1 genes functioned as APC for two influenza-specific, human Th cell clones with comparable efficiency to a DR1-expressing human lymphoblastoid cell line. In order to investigate the restriction specificity of the two Th clones, a transfectant expressing the species-mismatched MHC class II dimer DR1:I-E was tested as an APC. Both T cells showed no loss of Ag sensitivity due to substitution of the murine chain. One of the Th clones, TLC 72, showed even greater degeneracy by responding to Ag in the context of I-Ek. Taking into account the lower level of MHC class II expression on the I-Ek transfectant, there is remarkably little loss of efficiency of Ag-induced T cell activation due to the substitution of I-E for DR as restriction element. The Ag-specific responses of both clones were inhibited by anti-CD4 antibody when DR-transfected L cells or human lymphoblastoid cells were used as APC. This inhibition was also seen when Ag was presented to TLC72 by the I-Ek-expressing transfectant. Whether this inhibition is the result of negative signaling or of blocking an interaction between human CD4 and I-Ek is discussed. Similarly the inhibitory effects of mAb against the T cell accessory molecule LFA/1 were the same for both clones when either the transfectants or the lymphoblastoid cell line were used as APC, suggesting that L cells may express a molecule that is capable of acting as a ligand for human LFA/1. The results presented here further illustrate the value of transfectants in analyzing T cell recognition and accessory cell requirements. The patterns of degeneracy of MHC restriction exhibited by these clones provides a platform for a more detailed analysis of key residues involved in MHC class II-restricted T cell Ag recognition.

The inhibitory effects of mycobacterial lipoarabinomannan and polysaccharides upon polyclonal and monoclonal human T cell proliferation

Lipoarabinomannan from Mycobacterium tuberculosis was able to inhibit antigen induced T cell proliferation of human CD4+ T cell clones specific for influenza virus. The inhibitory effect was also present when peripheral human T cells were stimulated with crude mycobacterial antigen extracts. Non-specific T cell stimulation, i.e. IL-2, PHA and anti-CD3 antibodies coupled to beads, was not affected. The inhibitory property was also found when arabinomannan and arabinogalactan of mycobacterial origin were tested but not with other unrelated polysaccharides used as controls. The effect appears to be related to the processing of the antigen by the antigen-presenting cells, since it was evident when T cell clones were stimulated with whole virus, whereas stimulation with a synthetic peptide containing the relevant epitope was not inhibitable.

Viscoelasticity of F-actin and F-actin/gelsolin complexes

Actin is the major protein of eukaryote peripheral cytoplasm where its mechanical effects could determine cell shape and motility. The mechanical properties of purified F-actin, whether it is a viscoelastic fluid or an elastic solid, have been a subject of controversy. Mainstream polymer theory predicts that filaments as long as those found in purified F-actin are so interpenetrated as to appear immobile in measurements over a reasonable time with available instrumentation and that the fluidity of F-actin could only be manifest if the filaments were shortened. We show that the static and dynamic elastic moduli below a critical degree of shear strain are much higher than previously reported, consistent with extreme interpenetration, but that higher strain or treatment with very low concentrations of the F-actin severing protein gelsolin greatly diminish the moduli and cause F-actin to exhibit rheologic behavior expected for independent semidilute rods, and defined by the dimensions of the filaments, including shear rate independent viscosity below a critical shear rate. The findings show that shortening of actin filaments sufficiently to permit reasonable measurements brings out their viscoelastic fluid properties. Since gelsolin shortens F-actin, it is likely that the effect of high strain is also to fragment a population of long actin filaments. We confirmed recent findings that the viscosity of F-actin is inversely proportional to the shear rate, consistent with an indeterminate fluid, but found that gelsolin abolishes this unusual shear rate dependence, indicating that it results from filament disruption during the viscosity measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of fine needle aspiration cytology in breast cancer screening

In a six year period up to the end of December 1985 fine needle aspiration cytology specimens of the breast were obtained from 562 apparently healthy women invited to participate in a breast cancer screening programme. Of these, 397 had a biopsy and 173 cancers were confirmed histologically. For the diagnosis of cancer, the procedure was less successful than in symptomatic cases. The main factors influencing success were the aspirator, the small size of many cancers, and the occult nature of the lesions seen only on mammography. Retrospective analysis of the figures shows that combining the results of FNA cytology in a triple assessment with physical and mammographical findings for restricted selection means that the number of benign biopsy specimens could be reduced considerably.

The determination of urinary 3-methyladenine in humans as a potential monitor of exposure to methylating agents

The determination of urinary 3-methyladenine has been explored as a potential monitor of exposure to methylating carcinogens. A method based on the use of high resolution gas chromatography--mass spectrometry has been developed for measuring this methylated base in human urine. Urine is extracted by XAD-2 column chromatography and the extract purified by reverse phase C18 h.p.l.c. Derivatization with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide yields the mono-tert-butyldimethylsilyl derivative of 3-methyladenine which has good gas chromatographic properties and is stable towards hydrolysis. The gas chromatographic separation was carried out using an SE-52 capillary column and quantitation made by electron impact selective ion monitoring mass spectrometry employing deuterium-labelled 3-methyladenine added initially to the urine as internal standard. Measurable levels (4.50-16.07 micrograms/24 h) of the methylated base have been found in control (i.e. nominally unexposed) human urines.

Suppression of delayed hypersensitivity skin reactions to tuberculin by M. leprae antigens in patients with lepromatous and tuberculoid leprosy

Delayed hypersensitivity skin reactions to tuberculin when injected alone or in mixture with antigens of M. leprae were examined in leprosy patients and in healthy controls. The tuberculin reaction was significantly inhibited in more than one half of both LL and BT patients by the soluble extract of M. leprae (leprosin), the leprosin derived 12 kD protein or leprosin depleted of the 12 kD antigen. However, suppression was not found in healthy controls from a leprosy endemic region. These results suggest that multiple M. leprae-specific antigens have an immunoregulatory function. Since suppression was demonstrable not only in LL (leprosin-anergic), but also in BT (leprosin-responder) patients it is of interest that the 'mixed' skin test can discriminate the immune status of at least certain BT patients from that of the infected but self-healing healthy controls. Corollary lymphocyte cultures failed to show any suppression by leprosing of the lymphoproliferative responses to tuberculin.

Reversal of cardiac transplant rejection without massive immunosuppression

Although cyclosporine has decreased the severity of acute cardiac transplant rejection, most centers have continued to use high-dose intravenous steroids to treat acute rejection. To minimize the morbidity of antirejection therapy, acute rejection episodes in 37 cardiac transplant recipients were treated prospectively with only a boost of oral prednisone. Cyclosporine was continued at the same maintenance dose while oral prednisone was increased to 100 mg/day for 3 days, then rapidly tapered over 1 week to the maintenance dose. Seventy-six of 85 acute rejection episodes (90%) showed histologic resolution of mycocyte necrosis on repeat biopsy. Three acute rejection episodes (3.5%) resolved only after "rescue therapy" with intravenous steroid, and an additional three episodes (3.5%) required the combination of intravenous steroid and rabbit antithymocyte globulin to effect resolution. In addition, three acute rejection episodes (3.5%) resulted in graft loss. This was fatal in two patients and one patient underwent successful retransplantation. Oral steroid therapy alone is adequate therapy for most acute rejection episodes in cyclosporine-treated heart transplant recipients, and low infectious morbidity and mortality has been associated with this antirejection protocol.

Immunological activity of a 38-kilodalton protein purified from Mycobacterium tuberculosis

A 38-kilodalton (kDa) protein antigen from Mycobacterium tuberculosis was purified by monoclonal antibody TB71-based affinity chromatography. This molecule carries two nonoverlapping epitopes recognized by monoclonal antibodies TB71 and TB72, which are expressed substantially more strongly by M. tuberculosis than by Mycobacterium bovis. However, cross-reactive determinants between these two species were revealed on the 38-kDa protein by a rabbit anti-BCG serum. An immunoradiometric assay based on the TB71 and TB72 antibody pair specifically determined 38-kDa-antigen concentrations in mycobacterial extracts. Antibodies in sera from tuberculosis patients estimated by binding to 38-kDa-antigen-coated microtiter plates were positively correlated with TB72 competing titers. Unlike antibodies, T-cell proliferative responses to the 38-kDa protein were expressed equally by 60% of tuberculosis patients and healthy BCG-vaccinated subjects. Similarly, delayed-type hypersensitivity skin reactions were elicited in both M. tuberculosis- and M. bovis-sensitized guinea pigs. The results suggest the immunodominance of the species-specific B-cell and cross-reactive T-cell stimulatory epitopes.

Portasystemic shunt fraction quantification with colonic iodine-123 iodoamphetamine

Portasystemic shunting was quantified in dogs with [123I]iodoamphetamine (IMP) administered transrectally into the colon and monitored externally with a gamma camera. IMP was absorbed rapidly and unchanged from the colon. After direct injection into the portal vein, IMP was almost completely extracted by the liver on the first pass, and the washout half-life was approximately 60 min. Based on these kinetic data, computer simulation of this biologic system was carried out. Errors associated with simplified models are calculated. The simplest model with insignificant error, which assumed that the tracer behaved like microspheres, was used to quantitate portasystemic shunt fraction in animals with surgically created shunts. Results were compared with the standard of 99mTc-labeled macroaggregated albumin infused into a branch of inferior mesenteric vein. For shunt fractions ranging from 0 to 100%, an excellent correlation was seen, indicating that this approach is potentially a simple, noninvasive method of portasystemic shunt fraction quantification.

Comparative pathology of prevalent and incident cancers detected by breast screening. Edinburgh Breast Screening Project

In the Edinburgh Breast Screening Project 210 cancers were detected from commencement in 1979 up to December, 1984. By this time the full initial cohort had completed at least 3 visits and a proportion had attended for up to 5 visits, so pathological characteristics for prevalent and incident cancers could be compared. The main differences are in distribution of histological type of cancer, detection of occult invasive disease, and lymph-node positivity among incident tumours. Only the first of these was statistically significant. This evaluation shows that cancer detection by screening in Edinburgh conforms with screening theory, in which detection of good prognosis tumours is favoured at the prevalence screens, and faster growing, aggressive tumours are found at the incidence screens. Qualitative histopathology may provide a better measure than standard quantitative judgments of size and lymph node status to compare the varieties of cancer detected by screening programmes and to understand the biology of the disease.

Right ventricular ejection fraction measured by first-pass intravenous krypton-81m: reproducibility and comparison with technetium-99m

Study of the effects of various diseases and therapeutic manipulation of pulmonary vascular resistance on the right ventricle has been restricted by methodologic limitations. The radioactive gas in solution, krypton-81m was used to study the right ventricle and the technique was compared with a technetium-99m method. In 22 subjects, first-pass krypton-81m right ventricular ejection fraction, acquired both in list mode and electrocardiogram-gated frame mode, correlated well (r = 0.81 and 0.86, respectively, p less than 0.01) with that determined by technetium-99m first-pass studies over a broad range of ventricular function. The reproducibility of the technique was excellent (r = 0.84 and 0.95 for each acquisition mode, respectively). Krypton-81m first-pass studies provide accurate and reproducible estimates of right ventricular function. Use of krypton allows multiple measurements, with or without perturbations, over a short period of time.

Reduced infection in cardiac transplant recipients

Despite the introduction of cyclosporine immunosuppression, infectious morbidity and mortality in cardiac transplant recipients has remained high. To decrease infectious complications, lower doses of cyclosporine and oral prednisone than previously reported were used for maintenance immunosuppression in 22 operative survivors of orthotopic cardiac transplantation. Twelve infections occurred in 10 patients followed 8 +/- 5 months. Fifty-five percent of patients had no infectious complications. There were no deaths. Seven infections required hospitalization for a mean of 12 days. Infection rate per patient for the first 3 months after transplantation was 0.23 compared with a range of 0.82 to 1.06 in series previously reported in which higher doses of steroids were used. Lowered doses of steroid can be used for maintenance immunosuppression and treatment of rejection with acceptable short-term results. With such a protocol, a low incidence of controllable infectious complications with no deaths has been observed.

Functional expression of HLA-DP genes transfected into mouse fibroblasts

The HLA class II antigens are a highly polymorphic family of dimeric cell-surface glycoproteins, expressed predominantly on the surface of immunocompetent cells. They are intimately involved with the induction of the T-cell response to extrinsic antigen and are important predisposing factors for a wide spectrum of autoimmune diseases. We describe here the expression of a class II product from the HLA-DP (new WHO nomenclature, formerly SB) subregion after transfer of cloned genes into mouse fibroblasts. The transfected DP antigen is recognized by several HLA class II monoclonal antibodies and, though present in a mouse cell background, is able to function in the presentation of influenza antigen to cloned DP-restricted human T lymphocytes.

Fine needle aspiration cytology, in relationships to clinical examination and mammography in the diagnosis of a solid breast mass

The accuracy of clinical examination, mammography and fine needle aspiration cytology in identifying malignancy has been assessed in 1655 breast masses from two time periods. Clinical examination and mammography remained consistent at identifying malignancy but 9 per cent of all breast carcinomas were considered benign by both techniques (sensitivity 91 per cent). Fine needle aspiration cytology, when performed by multiple aspirators in the first study period, had a sensitivity of only 66 per cent for malignancy. During the second period of study, when all aspirates were performed by a single aspirator, sensitivity rose to 99 per cent. The two patients with false negative cytology in this latter period had both clinical and mammographic evidence of malignancy. No patient with malignant cytology was subsequently shown to have benign disease. It is concluded that a combination of clinical examination and mammography, with fine needle aspiration cytology performed by committed individuals with aptitude for the technique and interpreted by experienced pathologists, can identify all patients with breast cancer before surgery.

The Edinburgh randomised trial of screening for breast cancer: description of method

Edinburgh was selected as one of the centres in the UK Seven-year Trial of Breast Screening of women aged 45-65 which began in 1979. Subsequently, our study was extended to a randomised trial with its own control population within the city. Half the practices were randomly allocated for screening, giving a cluster sampling of women. The total number in the trial is 65,000. Women with previously diagnosed breast cancer are excluded. Women allocated for screening are invited to the clinic and screened according to the procedures specified in the U.K. protocol, having clinical examination every year and mammography on alternate years. The two modalities of screening are assessed independently and the role of nurses is being evaluated. Breast cancer incidence is monitored by pathology register and the local cancer registry office and deaths from the General Register office. Long-term follow-up will be obtained through flagging at NHS Central Register. To determine the value of screening, standard statistical methods will be used to compare breast cancer mortality rates in the whole of the screening population with that of the controls. This trial has a power of 83% of detecting a reduction in mortality of 35% after 7 years of follow-up and a power of 95% of detecting a similar reduction at 10 years (alpha = 0.05, one-sided test).

Determination of N-7-[2H3]methyl guanine in rat urine by gas chromatography-mass spectrometry following administration of trideuteromethylating agents or precursors

A gas chromatographic-mass spectrometric method has been developed for the determination of N-7-[2H3]methyl guanine in urine in the presence of large natural levels of N-7-methyl guanine. Urine is fractionated on heptanesulfonic acid-treated C-18 Sep-pak cartridges, followed by derivatization to give a volatile N-heptafluorobutyryl-O6-2,3,4,5, 6-pentafluorobenzyl derivative which is separated on an SE52 fused silica capillary column. Using N-7-ethyl guanine as an internal standard, the total amount of N-7-methyl guanine is determined by gas chromatography-flame ionization detection. The percentage of N-7-[2H3]methyl guanine is then measured by gas chromatography-mass spectrometry, enabling the amount of deuterated base to be determined. Preliminary experiments with [2H3]methyl methanesulfonate in rats showed measurable excretion of N-7-[2H3]methyl guanine. 4-(Di[2H3]methylamino)antipyrine alone gave no detectable amount of alkylated base, but coadministration of nitrite resulted in excretion of deuterated N-7-methyl guanine.

Alpha-thalassaemia caused by a polyadenylation signal mutation

Most eukaryotic messenger RNAs have the sequence AAUAAA 11-30 nucleotides from the 3'-terminal poly(A) tract. Since this is the only significant sequence homology in the 3' non-coding region it has been suggested that it may be a recognition site for enzymes involved in polyadenylation and/or termination of polymerase II transcription. This idea is strengthened by observations on the effect of deletion mutations in or around the AATAAA sequence on polyadenylation of late simian virus 40 (SV40) mRNA; removal of this sequence prevents poly(A) addition. Naturally occurring variants of this hexanucleotide are rare and hitherto their functional significance has not been assessed. We have now identified a human alpha 2-globin gene which contains a single point mutation in this hexanucleotide (AATAAA leads to AATAAG). The paired alpha 1 gene on the same chromosome is completely inactivated by a frame-shift mutation. This unique combination has enabled the expression of the mutant alpha 2 gene to be studied in vivo where it has been found that the accumulated level of alpha 2-specific mRNA in erythroid cells is reduced. Furthermore, readthrough transcripts extending beyond the normal poly(A) addition site are detected in mRNA obtained from HeLa cells transfected with cloned DNA from the mutant alpha 2 gene, suggesting that the single nucleotide change in the AATAAA sequence is the cause of its abnormal expression.

Localization and excision of occult breast lesions

Between 1976 and 1982, 190 non-palpable mammographic abnormalities considered to be suspicious of malignancy were excised using a needle localization technique. The indications for biopsy, technique for localization, method for confirmation of excision and histopathological preparation are presented. The histopathological diagnosis of these lesions were 150 benign and 40 malignant. There was no clear correlation between the mammographic appearances and the occurrence of cancer. Compared with 100 consecutive women with palpable breast cancer the impalpable and mammographically detected tumours were smaller, more often non-invasive and associated with negative axillary nodes.

Microcalcification and its relationship to cancer of the breast: experience in a screening clinic

The mammograms and specimen radiographs of 45 women in whom the presence of microcalcification played a major part in the decision to biopsy, were studied to determine possible distinguishing features. A mammographic lesion of 150 mm2 or less with an irregular density and five or more calcific particles, especially if palpable, was very likely to be an invasive carcinoma. With improved resolution, it should become possible to distinguish those calcifications covering 150 mm2 or less in the mammograms which are associated with parenchymal structures and those that are associated with stromal elements. Features that may potentially distinguish some benign parenchymal calcifications and those parenchymal calcifications associated with non-invasive malignancy are described. There will probably remain a few benign parenchymal associated calcifications which are identical to the calcifications associated with non-invasive cancer. Implications for improvement in technique are considered.

Specific craniofacial defects induced by jervine in the cultured rat embryo

The Veratrum-derived steroidal alkaloid, jervine, induces cyclopia and limb malformations in sheep, and various other craniofacial malformations in several other mammalian and avian species. In the present study, the question whether jervine acts directly or indirectly on mammalian embryos to produce malformations and the nature of the target tissue or cells were examined using whole-embryo cultures of the CD rat. Embryos were explanted into culture at the presomite, early neurula stage and cultured in the presence or absence of jervine for 48 hours. Jervine (at 1-5 micrograms/ml) induced an oblong-head appearance and ventrally displaced optic vesicles, with little or no other effects observed on overall growth and development. The specific target tissue in the embryo was found to be the cranial neuroepithelium. This specificity of action is quite unusual since most teratogens examined in whole-embryo culture to date have various nonspecific effects on embryonic growth and differentiation.