Preliminary images from an adaptive imaging system.

I-ImaS (Intelligent Imaging Sensors) is a European project aiming to produce real-time adaptive X-ray imaging systems using Monolithic Active Pixel Sensors (MAPS) to create images with maximum diagnostic information within given dose constraints. Initial systems concentrate on mammography and cephalography. In our system, the exposure in each image region is optimised and the beam intensity is a function of tissue thickness and attenuation, and also of local physical and statistical parameters in the image. Using a linear array of detectors, the system will perform on-line analysis of the image during the scan, followed by optimisation of the X-ray intensity to obtain the maximum diagnostic information from the region of interest while minimising exposure of diagnostically less important regions. This paper presents preliminary images obtained with a small area CMOS detector developed for this application. Wedge systems were used to modulate the beam intensity during breast and dental imaging using suitable X-ray spectra. The sensitive imaging area of the sensor is 512 x 32 pixels 32 x 32 microm(2) in size. The sensors' X-ray sensitivity was increased by coupling to a structured CsI(Tl) scintillator. In order to develop the I-ImaS prototype, the on-line data analysis and data acquisition control are based on custom-developed electronics using multiple FPGAs. Images of both breast tissues and jaw samples were acquired and different exposure optimisation algorithms applied. Results are very promising since the average dose has been reduced to around 60% of the dose delivered by conventional imaging systems without decrease in the visibility of details.

Breast-conserving surgery with intra-operative radiotherapy: the right approach for the 21st century?

Wide local excision followed by external beam radiation therapy (EBRT) to the whole breast has become the standard of care for most patients with localised 'early' breast cancer in the UK, Europe, and the USA. Local relapse rates are low, and overall survival figures have improved during the past decade, with the advent of more effective systemic endocrine- and chemo-therapy. A policy of EBRT for every patient undergoing breast conserving surgery (BCS) is however associated with a number of practical difficulties, acute radiation side effects and longer term toxicity, all of which detract from the obvious benefits of EBRT. In addition, with a disease as common as early breast cancer and a treatment programme typically requiring sophisticated radiation planning and many fractions of treatment, the policy of BCS plus EBRT has enormous resource implications within departments of oncology, greatly contributing to lengthy pre-treatment delays. For all these reasons, we and others have developed an increasing interest in techniques of partial breast irradiation, with an emphasis in our own Department on the emerging technique of intra-operative radiotherapy (IORT), which we initially employed as a boost to the tumour bed for use in conjunction with EBRT to the whole breast. To test the possibility of replacing the whole of the EBRT 3-6 week programme by a single application of IORT at the time of surgery, we and others have commenced a large scale prospectively randomised clinical trail in selected patients. Nine international centres are currently participating, and 350 patients have now been randomised to receive either IORT as part of the initial surgical excision or conventional EBRT with a pragmatic dose policy according to the preference of the contributing centre. The majority of patients undergoing IORT receive this at the time of initial surgery but it is also permissible within the trial programme to randomise suitable patients after the excised specimen has been histologically examined, thus avoiding any unsuitable patients - for example, those with a lobular carcinoma. These patients will be stratified and assessed separately from the 'pre-pathology' group, whose surgery and IORT is completed within a single session; if the latter patients are found to have unfavourable histology we have the facility, within the trial, to add EBRT. The trial is ongoing and our early experience has been encouraging. We have also recently assessed the long term local failure rate in patients offered IORT as a tumour bed boost, in conjunction with conventional EBRT. This methodology will also be the subject of a future randomised clinical trial.

Targeted intra-operative radiotherapy (Targit): an innovative method of treatment for early breast cancer.

INTRODUCTION: We believe that conservative treatment of early breast cancer may not require radiotherapy that encompasses the whole breast. We present here the clinico-pathological basis for this view, as well as a novel therapeutic approach that allows intra-operative radiotherapy to be safely and accurately delivered to the target tissues in a standard operating theatre. THE RATIONALE: Whole-organ analysis of mastectomy specimens reveals that 80% of occult cancer foci are situated remote from the index quadrant. In contrast, over 90% of local recurrences after breast conservative therapy occur near the original tumour, even when radiotherapy is not given. Therefore, the remote occult cancer foci may be clinically irrelevant and radiotherapy to the index quadrant alone might be sufficient. A NOVEL TECHNIQUE: The Photon Radiosurgery System (PRS) is an ingenious portable electron-beam driven device that can typically deliver intra-operative doses of 5-20 Gy, respectively, to 1 cm and 0.2 cm from the tumour bed over about 22 min. The pliable breast tissue--the target--wraps around the source, providing perfect conformal radiotherapy. Being soft X-rays, the dose attenuates rapidly (alpha approximately 1/r3), reducing distant damage. RESULTS: In our pilot study of 25 patients (age 30-80 years, T = 0.42-4.0 cm), we replaced the routine post-operative tumour bed boost with targeted intra-operative radiotherapy. There have been no major complications and no patient has developed local recurrence, although the median follow-up time is short, at 24 months. CONCLUSION: It is safe and feasible to deliver targeted intraoperative radiotherapy (Targit) for early breast cancer. We have begun a randomised trial--the first of its kind--comparing Targit with conventional six-week course of radiotherapy. If proven equivalent in terms of local recurrence and cosmesis, it could eliminate the need for the usual six-week course of post-operative radiotherapy.

Pure red cell aplasia of long duration complicating major ABO-incompatible bone marrow transplantation.

In 3 of 15 consecutive patients receiving a human leukocyte antigen (HLA)-identical but major ABO incompatible bone marrow transplant (BMT), pure red cell aplasia (PRA) lasting 5 to 8 months was observed. Titers of the incompatible anti-A agglutinin before infusion of the red blood cell (RBC)-depleted BMT was very high in one, and in the usual range in two patients. Decrease of agglutinin titers during the first 4 weeks after BMT were comparable between PRA patients and those of ABO-incompatible BMT recipients with timely RBC recovery. However, in PRA patients, agglutinin titers rose again and remained elevated for 19 to 28 weeks. RBC engraftment and reticulocyte recovery ultimately occurred spontaneously and coincided with the decrease of agglutinin titers below 16. These observations indicate that PRA is antibody-dependent in this setting. Furthermore, it is conceivable that cyclosporine facilitates recipient-derived antibody synthesis after major ABO-incompatible BMT.

Delayed alloimmunization using random single donor platelet transfusions: a prospective study in thrombocytopenic patients with acute leukemia.

A randomized study was performed in 54 thrombocytopenic patients with acute leukemia. Alloimmunization of recipients of random multiple-donor platelet concentrates (MD group) was compared to that of patients receiving random single-donor platelets (SD group). In the SD patients, formation of alloantibodies (mostly anti-HLA) occurred less frequently (p less than 0.002), after a longer time period (p less than 0.002), and after a higher number of transfusions (p less than 0.005) as compared to MD patients. SD patients also became refractory to random platelets less frequently (p less than 0.005), after a longer time period, and after a higher number of transfusions (p less than 0.02). In SD patients, the increments after the first and the last transfusion were in the same range, whereas in MD patients, the 1-hr (p less than 0.001) and the 24-hr (p less than 0.025) increments decreased from the first to the last transfusion. Thus, the use of random SD platelet transfusions postponed alloimmunization.

46,XX/46,XY chimerism in a phenotypically normal man.

Some twenty cases of dispermic chimeras with the karyotype 46,XX/46,XY, discovered because of gonadal dysplasias or a true hermaphroditism, have been reported. This is a report of a phenotypically normal man with 46,XX/46,XY chimerism in whom a prepubertal finding of positive X-chromatin was interpreted as Klinefelter syndrome. The diagnosis was revised 11 years later when the family doctor, who doubted the earlier diagnosis because of the patient's normal-sized testes, sent him to an outpatient clinic. The young man was 23 years old, athletic (74kg, 180cm), with normal body proportions, normal sexual hair distribution, normal libido and potency, normal endocrine parameters, and a normal spermiogram. The karyotype revealed an XX/XY mosaic in a proportion of 1:2. An identical set of maternal markers (Q- and C-banding) was present in male and female cells. Differences were found with respect to two paternal markers. Furthermore, blood, serum, and red cell enzyme groups in five systems showed two phenotypes, again with duality of paternal origin. It is concluded that a positive X-chromatin in prepuperty, especially in the absence of supporting clinical features, must be followed by a karyotype study.

Immunochemical properties of Mg erythrocytes.

The major erythrocyte membrane (MN) sialoglycoprotein in Mg red cells was found to exhibit a slightly decreased sodium-dodecyl-sulphate polyacrylamide gel electrophoretic molecular weight and periodic and/Schiff staining intensity. Mg antigen activity was shown to be associated with this molecule. As judged from chemical modification experiments, no carbohydrate but the glycoprotein's N-terminal amino acid is involved in the Mg receptor site. The endgroup of the glycoprotein was found to leucine and studies involving Staphylococcus aureus V8 protease suggest that a glutamic acid is located at the fifth position of its peptide chain. This indicates that the Mgs gene complex evolved from a mutation of an Ns allele. An amino acido substitution or deletion at the second, third and/or fourth position(s), preventing the glycosylation of all or some of these amino acids, provides an explanation for the properties of Mg erythrocytes.

Mg and Mc: mutations within the amino-terminal region of glycophorin A.

M and N are the two common ("normal") alleles at the MN locus of the MNSs blood group system. The antigens M and N that they determine are located within the amino-terminal region of glycophorin A. In the serologically active and glycosylated (*) fragment of glycophorin AN the sequence is Leu-Ser*-Thr*-Thr*-Glu-, and in that of glycophorin AM it is Ser-Ser*-Thr*-Thr*-Gly-. Mg and Mc are very rare ("variant") alleles of M and N; as to the corresponding antigens, Mg is serologically quite distinct from M and N, while Mc is a compound of both. Erythrocytes of genotypes MgN, MgM, MgMg, and McM, which were the object of the present study, contain normal amounts of glycophorin A in their membrane. In glycophorin AMg the amino-terminal sequence is related to that of glycophorin AN by substitution of asparagine for threonine in position 4, and it is nonglycosylated: Leu-Ser-Thr-Asn-Glu-. The corresponding structure of glycophorin AMc is Ser-Ser*-Thr*-Thr*-Glu-; it is thus closely related to that of glycophorin AN and AM, by substitution of the amino acids in positions 1 or 5, respectively. All of these substitutions can be explained by single base changes. The distinctions in chemical structure not only confirm the location of M and N in this region of glycophorin A, because they are the only differences observed, but also indicate, because they are correlated with the distinctions in antigenic specificity, that M and N are structural genes coding for amino acid sequences. The finding that Mc contains structural features of both M and N suggests that these two forms of glycophorin A have evolved from a common ancestral gene by single base substitutions at sites in the genome coding for amino acids in positions 1 and 5 of the sequence. Carbohydrate structures, however, are also necessary for full expression of antigens M and N. Glycosylation during biosynthesis of residues within the polypeptide appears to depend on a particular protein structure.

Dominant myotonia congenita: pedigree with skipping of one generation.

The skipping of one generation in a family pedigree with dominant myotonia congenita is reported. It is suggested that non-penetrance in this condition occurs and should be considered in genetic counselling as a rare, but realistic possibility.

[MNSs system, erythrocyte membrane and false paternity exclusion]. / Système MNSs, membrane érythrocytaire et fausse exclusion de parenté.

The modification of the red cell membrane first observed by Darnborough and co-workers in En (a-) and EnaEn heterozygous persons, and characterized by a) exaggerated agglutinability of the cells by various serological reagents, b) decrease of their electric surface charge, and c) reduction of their sialic acid content, is shown to be regularly and, to all appearances, directly associated with weakness or absence of MN antigenic substance; it is not seen in comparable "variants" of the Ss antigens. This type of modified cell membrane is thus found in the presence of Mg, of weak forms of M or N (N2 with or without a positive direct antiglobulin test, or as produced by the gene complexes MS.Sta, Ms.Sta, MsMi.V or NsMi.V) and when antigen production at the MN locus is inhibited, completely or almost completely, by the "operator" genes En or Mk. Apparent exclusions of parentage due to some of the genes involved, particularly Mg, En and Mk, are presented. On the other hand, the NNSs genotypes of members of the 3 known families with an En(a-) propositus are discussed and a revised interpretation of them is given, based on renewed serological studies of the persons concerned. A genetical scheme of the MNSs system, comprising four "structural" loci-Ena MN, U Ss-and three "operators", is proposed.

Freeze-fracture electron microscopy of human erythrocytes lacking the major membrane sialoglycoprotein.

Human erythrocytes of blood group En (a-), a rare homozygous condition involving a complete lack of the major sialoglycoprotein of the cell membrane (glycophorin A), were compared with erythrocytes from normal (En (a+)) individuals by freeze-fracture electron microscopy. No decrease in number, or variation in morphology, of the intramembranal particles of En (a-) cells was detectable. The results show that the erythrocyte sialoglycoprotein is not essential for the maintenance of the integrity of the intramembranal particles of the human erythrocyte membrane.

Identification of sialosylparagloboside as the erythrocyte receptor for an 'anti-p' antibody.

A human antibody which preferentially agglutinates p erythrocytes is inhibited specifically by the glycolipid sialosylparagloboside, NeuNAc (alpha,2 leads to 3)Gal(beta,1 leads t0 4)GlcNAc(beta,1 leads to 3)Gal(beta,1 leads to 4)Glc-Cer and forms a precipitin band with this compound in agarose gel. Erythrocytes treated with neuraminidase are no longer agglutinated by this antibody, but the agglutination is not affected by papain treatment. Sialosylparagloboside is not a biosynthetic precursor of any of the P antigens, but it contains the lacto-N-neotetraose structure which is also present in the P1 glycolipid.

A Swiss family showing independent segregation of the Lutheran and Swann genes.

A family is reported in which the parents' mating is of the 'double back-cross' type with respect to the Sw, Lu and Se genes. The inheritance of these genes in the children shows, with reference to a possible linkage between Sw and the two other loci, four non-recombinants and three recombinants (or vice versa). The inheritance of the Lu and Se genes shows the well-known linkage between these two loci, with no instance of recombination. It is concluded that there is no evidence for close linkage between Sw and Lu-Se, and that the suggestion of a Sw-Lu linkage found in a family studied previously was due to chance.

MNSs and Miltenberger frequencies in 211 Chinese.

In serial MNSs tests on blood samples from 211 Chinese, 10 Mi(a+) were found, 9 of which were shown to belong to Miltenberger cell class III (Mi-III); it was assumed by analogy that this also applies to the tenth. The frequency of Mi-III in this Chinese series is thus 4.7%, almost 500 times higher than in Whites. Seventy persons in the series were tested for the Stones antigen: 2St(a+) were observed. Attention is drawn to the 'variant N' reactions of M Mi-III blood: positive with Vicia graminea extract, weakly positive with rabbit, negative with human anti-N. The reactions can be a source of error in MN tests on Chinese bloods.