What is the biological basis of pattern formation of skin lesions?

Pattern recognition is at the heart of clinical dermatology and dermatopathology. Yet, while every practitioner of the art of dermatological diagnosis recognizes the supreme value of diagnostic cues provided by defined patterns of 'efflorescences', few contemplate on the biological basis of pattern formation in and of skin lesions. Vice versa, developmental and theoretical biologists, who would be best prepared to study skin lesion patterns, are lamentably slow to discover this field as a uniquely instructive testing ground for probing theoretical concepts on pattern generation in the human system. As a result, we have at best scraped the surface of understanding the biological basis of pattern formation of skin lesions, and widely open questions dominate over definitive answer. As a symmetry-breaking force, pattern formation represents one of the most fundamental principles that nature enlists for system organization. Thus, the peculiar and often characteristic arrangements that skin lesions display provide a unique opportunity to reflect upon--and to experimentally dissect--the powerful organizing principles at the crossroads of developmental, skin and theoretical biology, genetics, and clinical dermatology that underlie these--increasingly less enigmatic--phenomena. The current 'Controversies' feature offers a range of different perspectives on how pattern formation of skin lesions can be approached. With this, we hope to encourage more systematic interdisciplinary research efforts geared at unraveling the many unsolved, yet utterly fascinating mysteries of dermatological pattern formation. In short: never a dull pattern!

Quantitative assessment of hematopoietic chimerism after allogeneic bone marrow transplantation has predictive value for the occurrence of irreversible graft failure and graft-vs.-host disease

Primary graft failure, secondary to either host-vs.-graft reaction or delayed engraftment, and graft-vs.-host disease (GVHD) are among the most difficult clinical problems to manage in the field of allogeneic bone marrow transplantation (BMT). Early diagnosis of both conditions would greatly improve their outcome. Using fluorescence in situ hybridization (FISH) with an X- and Y-probe mixture, we sequentially monitored chimerism of neutrophils and lymphoid cells from day 1 to 100 in 28 consecutive recipients of sex-mismatched unmanipulated bone marrow grafts. The objective was to quantitatively assess the evolution of chimerism during this crucial time interval and to determine whether chimerism patterns would be predictive of engraftment and GVHD. In recipients with primary graft failure (n=7), the presence of donor-type neutrophils and NK cells as well as the predominance of donor-type T cells distinguished patients who responded to G-CSF (n=5) from nonresponders (n=2). Furthermore, the clearance of host CD3+CD56- cells during days 5-10 posttransplantation was significantly hastened in patients who subsequently developed acute (delta=80%) or chronic (delta=81%) GVHD compared with patients without GVHD (delta=17%). Thus, our data suggest that molecular monitoring of the fate of host/donor hematopoietic cells in the early posttransplantation period could be useful in differentiating patients with delayed engraftment from those with irreversible rejection and in predicting the occurrence of GVHD as soon as day 10. This investigational approach may provide an appropriate basis on which to select adequate treatment for primary graft failure and high-risk candidates that could benefit from novel preemptive therapies for GVHD.

[Education in domestic violence]

A baccalaureate-level, mandatory course on the social aspects of violence against women is being given as part of the curriculum at the Université du Québec à Rimouski. The course has been offered since 1990 and includes a complete array of teaching techniques such as lectures, simulations and role playing. Its aim is to impart knowledge, develop awareness, promote a change of attitudes and develop intervention abilities for nurses who may come in contact with domestic violence situations. Prior to implementation, an exploratory study was completed to determine student nurses' perceptions of domestic violence. Results indicate that, prior to taking the course, domestic violence was perceived as an individual problem. Respondents (26 female and 2 male) generally accepted society's prejudices of domestic violence as fact and ignored research results that pointed to the social realities. By the end of the course, the respondents' knowledge of the social aspects of domestic violence was better integrated. The authors conclude that specific training on domestic violence can modify false perceptions and help nurses develop the necessary competencies to deal with these situations.

Sequential analysis of early hematopoietic reconstitution following allogeneic bone marrow transplantation with fluorescence in situ hybridization (FISH)

Using in situ hybridization with an X and Y chromosome probe mixture, we have sequentially studied peripheral blood samples from 10 patients (four males/six females) in an HLA-matched allogeneic setting in order to monitor the kinetics of early hematopoietic reconstitution. Interphase cells from smears consisting of purified granulocytic and lymphocytic populations respectively were studied in three patients at 24, 48, 72 and 96 h post-transplant. This period was arbitrarily defined as the immediate post-transplant period. These three patients plus seven others were studied sequentially at days 5, 10, 15, 20, 25 and 50 post-transplant, defined as the intermediate post-transplant period. The X and Y probes were indirectly labelled with rhodamine and fluoresceine isothiocyanate, respectively. Donor neutrophils were detected as early as 24 h post marrow infusion followed by a significant expansion at 48 h. At 96 h post-transplant, the median percentage of donor neutrophils was > 90%. In the immediate post-transplant period, most of the lymphocytes were of recipient origin. However, we have documented a significant expansion in donor lymphocytes, starting at day 5 post-transplant in most patients. Almost complete chimerism for the myeloid and lymphoid lineages was established at days 10 and 25 post-transplant, respectively. All patients engrafted normally according to standard clinical criteria. Follow-up data for those surviving > or = 100 days (eight patients), showed persistence of this pattern of hematopoietic reconstitution in all but one patient. Molecular monitoring of early engraftment has enabled us to unravel a distinct biphasic pattern of myeloid and lymphoid engraftment.

Cytogenic characterization of primary refractory anemia

Refractory anemia (RA) is the only myelodysplastic syndrome (MDS) devoid of quantitative marrow diagnostic criteria. The diagnosis rests mainly on the subjective identification of qualitative abnormalities according to the French-American-British criteria (FAB) involving one or more bone marrow hematopoietic cell lineages. The occurrence of nonrandom chromosome abnormalities remains the hallmark of the disease and the only means of investigation which confirms the disease objectively. With the purpose in mind to further characterize RA among MDS, we have undertaken a prospective high resolution banding chromosome analyses of bone marrow cells in patients with primary refractory anemia (PRA) with the aim of defining a cytogenetic phenotype and of assessing the clinical relevance of clonal abnormalities at initial diagnosis. Of 39 patients consecutively referred for chromosome analyses with a diagnosis of RA according to the FAB criteria, 27 patients had PRA and fulfilled our criteria for adequate chromosome analyses. Median age was 68 years. Fourteen of 27 patients (52%) had clonal chromosomal abnormalities at diagnosis. None of the patients showed a complex karyotype; 9/14 (64%) had a mixture of normal and abnormal cells. Interstitial or terminal deletions, involving chromosomes 5, 6, 7, 9, 11, 12, and 20, were found in 11/14 (79%) of the patients. Comparison of survival between patients with and without abnormalities showed no difference. The presence of clonal abnormalities did not predict transformation to acute myeloblastic leukemia (AML) nor was it associated with poor survival. In this study, patients with PRA were found to have a predominant pseudodiploid karyotypic pattern characterized by interstitial and/or terminal deletions as opposed to derivatives, specific and non-specific balanced translocations, or other structural and numerical abnormalities. We were unable to reveal any prognostic significance to the presence of these clonal abnormalities at initial diagnosis.

Maturation of short latency somatosensory evoked potentials by median nerve stimulation: a cross-sectional study in a large group of children

We have conducted two studies to evaluate the maturational changes of SEP in 206 subjects from neonatal period through adulthood. The first study was done with a cephalic reference electrode and included 137 subjects from 41 weeks (conceptional age) to 9 years of age, divided in 5 different age groups. In the second study, we used an extracephalic reference electrode and recorded SEPs in 69 normal subjects aged from 4 to 34 years, divided in 3 age groups. Our results show that there is a highly significant correlation between age and height in all the age groups studied. Peripheral and central components of SEP mature at different rates with adult values being reached for central conduction times (N9-P14, N9-N20, N13-N20 and P14-N20) between 4 and 9 years of age. Male and female subjects were compared in both studies and no significant differences were found in any of the age groups for any of the wave latencies or interpeak latencies analyzed.

Translocation (1;5)(q23;q33) in adult acute non-lymphocytic leukemia

Chromosome banding studies carried out on bone marrow cells from a 57-year-old white caucasian male with an M1 acute non-lymphocytic leukemia (ANLL) revealed an unbalanced translocation involving chromosomes 1 and 5 [der(5)t(1;5)(q23;q33)] as part of complex abnormalities in 76% of the cells analyzed. This chromosomal abnormality is the first to be reported in an adult patient with acute non-lymphocytic leukemia. A review of previous reports on translocations involving the juxtaposition of the 1q23----qter DNA segment to other chromosomes suggests that this new translocation may be specifically involved with abnormal myeloid proliferation.

Prognostic value of clonal chromosomal abnormalities in patients with primary myelodysplastic syndromes

Chromosome analyses were carried out on bone marrow cells from 43 consecutive patients with primary myelodysplastic syndromes (MDS), classified according to the French-American-British (FAB) cooperative group criteria. The objective was to evaluate the prognostic value of clonal chromosomal abnormalities and of an excess of blasts for early death from acute nonlymphocytic leukemia (ANLL) and/or bone marrow failure (BMF). Patients were subdivided into two main groups: (1) refractory anemia without an excess of blasts (RAWEB), grouping patients with refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS), and (2) refractory anemia with an excess of blasts (RAEB), grouping patients with refractory anemia with an excess of blasts (RAEB) and refractory anemia with an excess of blasts in transformation (RAEBt). There were 29 patients with RAWEB and 14 with RAEB. The median time of observation was 26 months for RAWEB and 12 months for RAEB. Ten RAWEB patients (34%) and 11 RAEB patients (78%) had clonal chromosomal abnormalities. Among the ten RAWEB patients with clonal abnormalities, one (10%) died from ANLL, while of 19 RAWEB patients with a normal karyotype, two (10%) died from ANLL or BMF. The median survival for patients with RAWEB and an abnormal karyotype was not reached. In contrast, eight of the 11 RAEB patients with clonal chromosomal abnormalities (74%) died from ANLL or BMF. The median survival in this sub-group was 7 months. By using a Cox proportional hazard regression analysis, it was determined that a karyotype abnormality was not a significant predictory of survival once the contribution of the RAWEB/RAEB variable was taken into account. Being in the RAEB group was associated with a relative risk of 10.6 of dying from ANLL or BMF (beta = 2.36, standard error (SE) = 0.68, P = .0001). We conclude that classifying patients according to an excess of blasts will lead to a better prediction of survival than determining karyotype abnormality.

Interstitial deletion of the long arm of chromosome 5 (5q-) in leukemia and other hematological disorders: clinical and biological relevance of variable breakpoint patterns

From January 1983 to January 1985, we have found a deletion of the long arm of chromosome 5 (5q-) in the bone marrow cells of 8 patients; they represent consecutive patients referred to our institution for investigation and treatment of the following hematological disorders in whom the 5q- abnormality was found: acute nonlymphocytic leukemia (ANLL) (3), refractory anemia with excess blasts (RAEB) (2), preleukemia (PL) (1), sideroblastic anemia (SA) (1), refractory anemia (RA) (1). The deletion proved to be interstitial in all patients, with 3 different breakpoint patterns emerging: q13q33, q11.2q21, q11.2q33. Proximal breakpoint q11.2 was found only in patients with an initial diagnosis of ANLL. The common region deleted in all patients was comprised between bands q13q21. The clinical relevance and biological meaning of the heterogeneity of proximal and distal breakpoints found in this study are discussed.

14q+ abnormality with probable t(8;14)(q24;q32) in a young Haitian immigrant with acquired immunodeficiency syndrome and concomitant Burkitt's-like lymphoma

Cytogenetic analyses were carried out in a young Haitian immigrant with acquired immunodeficiency syndrome and concomitant Burkitt's-like lymphoma associated with massive bone marrow infiltration. A characteristic 14q+ abnormality was found in all bone marrow cells examined. Although chromosome abnormality involving band 8q24 was not evident in all the cells examined, some karyotypes show that the typical t(8;14)(q24;q32) is most probably present. No other complex rearrangements could be identified. This is the first report of concomitant acquired immunodeficiency syndrome and Burkitt's-like lymphoma in the Haitian community. Our cytogenetic findings provide further evidence for the role of specific chromosomal rearrangements in Burkitt's-like lymphoma oncogenesis in the setting of acquired immunodeficiency syndrome.

Therapy-induced preleukaemia in patients treated for Hodgkin's lymphoma: clinical and therapeutic relevance of sequential chromosome banding studies

Between January 1978 and December 1982 successful sequential chromosome analyses were carried out on bone marrow cells of five patients previously treated for Hodgkin's lymphoma (HL) presenting unexplained cytopenia or pancytopenia during follow-up. All patients had concurrent morphological examination of bone marrow specimens showing signs of dysplasia and/or hypoplasia, without leukaemic infiltrate. Six other patients treated for HL who had normal haematological parameters served as controls. All the patients with unexplained cytopenias had clonal chromosome abnormalities; monosomy for chromosome No. 5 was the most frequent. No abnormalities were detected in the control group. Two patients have evolved to resistant leukaemia, one died of sepsis before leukaemic conversion while severely neutropenic, and two are in full marrow and cytogenetic recovery after aggressive anti-leukaemic treatment in the pre-leukaemic phase. Our data suggest that cytogenetic studies may be of crucial value in detecting therapy-induced preleukaemia (t-PL) at an early stage of its evolution and in planning appropriate therapy before the establishment of overt leukaemia.

Childhood monosomy 7 syndrome

In recent years, chromosomal aberrations in various hematologic disorders have raised a great deal of interest. In fact, several nonrandom chromosomal abnormalities are now recognized to be responsible for a specific type of dyshemopoiesis while others are closely associated with characteristic hematologic features. Monosomy C, later shown to be monosomy 7 by different banding methods, has been described in children in relation to a peculiar myeloproliferative disorder. Retrospective analysis of early cases published in the literature and a recent observation that we wish to report suggest that the most consistent phenotypic expression of monosomy 7 is an increased susceptibility to bacterial infections related to a preleukemic dyshemopoiesis. Acute nonlymphocytic leukemia is the terminal event of this peculiar preleukemic syndrome, and thus suggests that monosomy 7 involves a stem cell already committed to myeloid differentiation.