Acute leukemia with promyelocytic features in PML/RARalpha transgenic mice

Acute promyelocytic leukemia (APL) is associated with reciprocal chromosomal translocations involving the retinoic acid receptor alpha (RARalpha) locus on chromosome 17. In the majority of cases, RARalpha translocates and fuses with the promyelocytic leukemia (PML) gene located on chromosome 15. The resulting fusion genes encode the two structurally unique PML/RARalpha and RARalpha/PML fusion proteins as well as aberrant PML gene products, the respective pathogenetic roles of which have not been elucidated. We have generated transgenic mice in which the PML/RARalpha fusion protein is specifically expressed in the myeloid-promyelocytic lineage. During their first year of life, all the PML/RARalpha transgenic mice have an abnormal hematopoiesis that can best be described as a myeloproliferative disorder. Between 12 and 14 months of age, 10% of them develop a form of acute leukemia with a differentiation block at the promyelocytic stage that closely mimics human APL even in its response to retinoic acid. Our results are conclusive in vivo evidence that PML/RARalpha plays a crucial role in the pathogenesis of APL.

Point mutation in kit receptor tyrosine kinase reveals essential roles for kit signaling in spermatogenesis and oogenesis without affecting other kit responses

The Kit receptor tyrosine kinase functions in hemato- poiesis, melanogenesis and gametogenesis. Kit receptor-mediated cellular responses include proliferation, survival, adhesion, secretion and differentiation. In mast cells, Kit-mediated recruitment and activation of phosphatidylinositol 3'-kinase (PI 3-kinase) produces phosphatidylinositol 3'-phosphates, plays a critical role in mediating cell adhesion and secretion and has contributory roles in mediating cell survival and proliferation. To investigate the consequences in vivo of blocking Kit-mediated PI 3-kinase activation we have mutated the binding site for the p85 subunit of PI 3-kinase in the Kit gene, using a knock-in strategy. Mutant mice have no pigment deficiency or impairment of steady-state hematopoiesis. However, gametogenesis is affected in several ways and tissue mast cell numbers are affected differentially. While primordial germ cells during embryonic development are not affected, Kit(Y719F)/Kit(Y719F) males are sterile due to a block at the premeiotic stages in spermatogenesis. Furthermore, adult males develop Leydig cell hyperplasia. The Leydig cell hyperplasia implies a role for Kit in Leydig cell differentiation and/or steroidogenesis. In mutant females follicle development is impaired at the cuboidal stages resulting in reduced fertility. Also, adult mutant females develop ovarian cysts and ovarian tubular hyperplasia. Therefore, a block in Kit receptor-mediated PI 3-kinase signaling may be compensated for in hematopoiesis, melanogenesis and primordial germ cell development, but is critical in spermatogenesis and oogenesis.

Murine embryonic stem cells without pig-a gene activity are competent for hematopoiesis with the PNH phenotype but not for clonal expansion

Paroxysmal nocturnal hemoglobinuria (PNH) develops in patients who have had a somatic mutation in the X-linked PIG-A gene in a hematopoietic stem cell; as a result, a proportion of blood cells are deficient in all glycosyl phosphatidylinositol (GPI)-anchored proteins. Although the PIG-A mutation explains the phenotype of PNH cells, the mechanism enabling the PNH stem cell to expand is not clear. To examine this growth behavior, and to investigate the role of GPI-linked proteins in hematopoietic differentiation, we have inactivated the pig-a gene by homologous recombination in mouse embryonic stem (ES) cells. In mouse chimeras, pig-a- ES cells were able to contribute to hematopoiesis and to differentiate into mature red cells, granulocytes, and lymphocytes with the PNH phenotype. The proportion of PNH red cells was substantial in the fetus, but decreased rapidly after birth. Likewise, PNH granulocytes could only be demonstrated in the young mouse. In contrast, the percentage of lymphocytes deficient in GPI-linked proteins was more stable. In vitro, pig-a- ES cells were able to form pig-a- embryoid bodies and to undergo hematopoietic (erythroid and myeloid) differentiation. The number and the percentage of pig-a- embryoid bodies with hematopoietic differentiation, however, were significantly lower when compared with wild-type embryoid bodies. Our findings demonstrate that murine ES cells with a nonfunctional pig-a gene are competent for hematopoiesis, and give rise to blood cells with the PNH phenotype. pig-a inactivation on its own, however, does not confer a proliferative advantage to the hematopoietic stem cell. This provides direct evidence for the notion that some additional factor(s) are needed for the expansion of the mutant clone in patients with PNH.

Consequences of exclusive expression in vivo of Kit-ligand lacking the major proteolytic cleavage site

Membrane growth factors that are processed to produce soluble ligands may function both as soluble factors and as membrane factors. The membrane growth factor Kit-ligand (KL), the ligand of the Kit receptor tyrosine kinase, is encoded at the Sl locus, and mice carrying Sl mutations have defects in hematopoiesis, gametogenesis, and melanogenesis. Two alternatively spliced KL transcripts encode two cell-associated KL protein products, KL-1 and KL-2. The KL-2 protein lacks the major proteolytic cleavage site for the generation of soluble KL, thus representing a more stable cell-associated form of KL. We investigated the consequences of exclusive expression of KL-2 in vivo. The KL gene in embryonic stem cells was modified and KL exon 6 was replaced with a PGKneoNTRtkpA cassette by homologous recombination, and mice carrying the SlKL2 allele were obtained. SlKL2/SlKL2 mice had only slightly reduced levels of soluble KL in their serum, suggesting that in vivo KL-2 may be processed to produce soluble KL-2S. The steady-state characteristics of the hematopoietic system and progenitor numbers were normal, and the mutant animals were not anemic. However, mast cell numbers in the skin and peritoneum were reduced and the mutant animals displayed increased sensitivity to sublethal doses of gamma-irradiation. Therefore, KL-2 may substitute for KL-1 in most situations with the exception of the production of mast cells, and induced proteolytic cleavage of KL-1 to produce soluble KL may have a role in the regeneration of hematopoietic tissue after radiation injury.

The amn gene product is required in extraembryonic tissues for the generation of middle primitive streak derivatives

The primitive streak is the defining feature of the gastrulating mouse embryo. Currently, little is known in the mouse about the mechanisms that mediate the assembly of the primitive streak or about the signaling pathways that specify the different types of mesoderm and endoderm generated from the streak. To gain insight into primitive streak assembly and function, we have conducted a detailed phenotypic characterization of amnionless, a transgene-induced insertional mouse mutation that arrests embryonic development during gastrulation. Our histological and molecular analyses, when examined in the context of the mouse gastrula fate map, lead to the model that middle streak formation is specifically impaired in the amnionless mutant. Significantly, these observations argue that the formation of the middle streak is mediated by a pathway that is genetically separable from those that direct the specification of the distal and proximal streak regions. Intriguingly, our findings from wt ES cell left and right arrow amnionless-/- blastocyst chimeras indicate that this proposed separate pathway for middle streak formation is dependent on amnionless gene functions in the visceral endoderm.

Genital manifestations of schistosomiasis mansoni in women: important but neglected

Egg-induced lesions in the upper and the lower female reproductive tract are important complications of the infection with Schistosoma mansoni. The understanding of the pathophysiology and pathology of genital lesions is only rudimentary, simple and reliable diagnostic tools are not at hand, epidemiological data do not exist and how to treat best the women affected, is not known. In view of recent advances in the understanding of genital lesions induced by S. haematobium the existing literature is critically analyzed and possible consequences of female genital schistosomiasis are outlined. We estimate that 6 to 27% girls and women with intestinal schistosomiasis, at least temporarily, suffer from pathology induced by eggs sequestered somewhere in their genital organs. This is a matter of concern and warrants more research into the epidemiology, pathology, diagnosis and therapy of this disease entity.

Renal lesions in leprosy: a retrospective study of 199 autopsies

In the present work, 199 patients with leprosy who underwent autopsy between 1970 and 1986 were retrospectively studied to determine the prevalence, types, clinical characteristics, and etiologic factors of renal lesions (RLs) in leprosy. Patients were divided into two groups: 144 patients with RLs (RL+) and 55 patients without RLs (RL-). RLs observed in 72% of the autopsied patients were amyloidosis (AMY) in 61 patients (31%), glomerulonephritis (GN) in 29 patients (14%), nephrosclerosis (NPS) in 22 patients (11%), tubulointerstitial nephritis (TIN) in 18 patients (9%), granuloma in 2 patients (1%), and other lesions in 12 patients (6%). AMY occurred most frequently in patients with lepromatous leprosy (36%; nonlepromatous leprosy, 5%; P < 0.01), recurrent erythema nodosum leprosum (33%; P < 0.02), and trophic ulcers (27%; 0.05 < P < 0.10). Ninety-seven percent of AMY was found in patients with lepromatous leprosy, 88% showed recurrent trophic ulcers, and 76% presented with erythema nodosum leprosum. NPS was found in older patients with arterial hypertension, neoplastic diseases, infectious diseases, and vasculitis associated with GN. Most patients with AMY presented with proteinuria (95%) and renal failure (88%). The most frequent causes of death were renal failure in patients with AMY (57%), infectious diseases in patients with GN (41%) and TIN (45%), and cardiovascular diseases in patients with NPS (41%). No difference in survival rates was observed among RL- patients and those with AMY, GN, NPS, or TIN.

Hyperlipidemia as a risk factor of renal allograft function impairment

In this study, the graft outcome in renal allograft recipients with [high cholesterol group (HCG), n = 30] or without [normal cholesterol group (NCG), n = 42] hypercholesterolemia and with [high triglyceride group (HTG), n = 33] or without [normal triglyceride group (NTG), n = 36] hypertriglyceridemia were prospectively compared. At 6 months post-transplantation, no significant difference was observed between the groups (NTG compared with HTG, and NCG compared with HCG) regarding age, presence of arterial hypertension, kind of donor (living related or cadaveric), immunosuppressive therapy, number of rejection episodes per patient, frequency of patients with acute cellular rejection, prevalence of patients with diabetes mellitus or proteinuria > 3 g/24 h, and mean serum creatinine. The probability of doubling serum creatinine during follow-up was statistically different between NTG and HTG (12 months: NTG = 0.03, HTG = 0.15; 36 months: NTG = 0.08, HTG = 0.33: 60 months: NTG = 0.08, HTG = 0.48; and 120 months: NTG = 0.18, HTG = 0.48), but not between NCG and HCG (12 months: NCG = 0.05, HCG = 0.13; 36 months: NCG = 0.13, HCG = 0.24; 60 months: NCG = 0.19, HCG = 0.31; 84 months: NCG = 0.27, HCG = 0.31). There was no significant difference in actuarial graft survival between HCG and NCG or between NTG and HTG. Hypertriglyceridemia, but not hypercholesterolemia, was associated with loss of graft function.

[Control of transmission of Chagas disease in Mambai-Goias, Brazil (1982-1984)]

A aplicação de inseticidas em Mambaí-GO, desde 1980, está determinando uma diminuição progressiva inicial de Triatoma infestans no intradomicilio, mas não a sua eliminação. A infestação triatominica foi detectada através de diversos métodos de vigilância imediata (transversal) e a longo prazo (longitudinal), com a colaboração dos próprios moradores. No primeiro ano de controle foi observada uma queda signiflcante de 28,6 % a 13,5%, mas devido a uma falha no programa de expurgos, em 1981, esta cifra voltou a elevar-se (23,2%). A continuidade desses expurgos nos anos seguintes resultou em um declínio gradual, atingindo em 1984 o nível de 14,2%. Simultaneamente a percentagem intradomiciliar de T. sórdida tendeu a aumentar, embora a infecção tripanossômica tenha sido sempre mínima. O conjunto destes achados sugerem que o controle do T. infestans com o uso exclusivo de inseticidas (BHC e Deltametrina) é difícil e oneroso. Precisando-se, portanto, o uso de medidas supletivas integradas aos sistemas de controle de doença de Chagas, que encorajam a participação ativa das comunidades afligidas, estimuladas mediante programas educativos.

Effect of mycophenolate mofetil on the progression of adriamycin nephropathy

In order to assess the effects of mycophenolate mofetil (MMF) on the development of adriamycin-induced nephropathy, the development of this nephropathy in rats treated with MMF was compared to that in non-treated animals (group ADR + V) over 28 weeks. At weeks 8, 16 and 20, 24-h proteinuria of the treated group statistically differed from that of the non-treated group. However, no significant difference in proteinuria was observed thereafter between the groups. At the end of the experiment, there was no significant difference between both groups regarding the frequency of glomerular lesion (Group ADR + V: Md = 35%, P25 = 20%, P75 = 68%; Group ADR + MMF: Md = 27%, P25 = 9.5%, P75 = 54%); tubulointerstitial lesion index (Group ADR + V: Md = 7, P25 = 1.5, P75 = 9; Group ADR + MMF: Md = 8, P25 = 2, P75 = 9); glomerulosclerosis area (group ADR + V = 2779 microm2, P25 = 751.8 microm2, P75 = 3115 microm2; Group ADR + MMF = 1147 microm2, P25 = 3969.7 microm2, P75 = 1560 microm2); and, interstitial fibrosis area (Group ADR + V: Md = 218200 microm2, P25 = 78670 microm2, P75 = 282700 microm2 group ADR + MMF: Md = 136000, P25 = 25010, P75 = 255800 microm2). In conclusion, MMF caused a temporary reduction in proteinuria but did not change the severity of the renal lesion observed after 28 weeks.

Sarcoma the great "masquerader" hematoma/deep vein thrombosis manifestation

INTRODUCTION

The clinical presentation of patients with soft-tissue sarcoma is highly variable. Most patients present with a painless mass, typically one that is increasing in size, and few have systemic symptoms such as fever, weight loss, or malaise. Soft tissue sarcomas can initially present as, or even be misdiagnosed as, deep venous thrombosis (DVT), leading to a late diagnosis.

CASE REPORT

A 51-year-old woman presented to the hospital with complaints of pain and swelling in her left thigh, interpreted as an infected hematoma with an associated deep vein thrombosis and treated accordingly. The patient presented to our emergency department two more times. In the last visit and due to an unresolving clinical scenario a MRI and surgical byopsies were made that confirmed a sarcoma diagnosis.

DISCUSSION

When a patient presents with an expanding, nontraumatic mass simulating a haematoma, several other differential diagnoses should be considered including aneurysm, bleeding tendency, chronic expanding haematoma and soft-tissue sarcoma. The growth of the tumor undetected while being treated for the DVT and then posteriorly for the hematoma, was without a doubt dismal to the patient, so earlier diagnosis would have been preferable.

CONCLUSION

When a patient presents with an unusual history of hematoma in the extremities, it is necessary to consider the possibility of a malignant soft tissue tumor.

Absence of cervical schistosomiasis among women from two areas of north–eastern Brazil with endemicSchistosoma mansoni

Genital manifestations in schistosomiasis haematobium are common and are associated with considerable morbidity. Although Schistosoma mansoni may also cause genital disease, the frequency of this complication is not known. Cervical biopsies (N=401) and Pap smears (N=981) were therefore collected from women living in two S. mansoni-endemic areas (in the states of Alagoas and Ceará, in north-eastern Brazil). The women were screened for the presence of sexually transmitted diseases and for the presence, in their cervical smears and/or biopsies, of S. mansoni eggs. Attempts at schistosomiasis control, which began in both study areas in 1977, have led to generally low intensities of infection (<30 eggs/g faeces in 99% of infections) and community prevalences of infection that range between 1% and 52%. As no schistosome ova were detected in any of the biopsies or smears, it appears that the risk, among women, of genital manifestations of S. mansoni infection is small in areas where the parasite load in the population is low (as the result of interventions to control intestinal schistosomiasis).

Importance of early and continuous use of protein restriction on the progression of adriamycin nephropathy

Three experimental protocols were carried out with the aim of evaluating the role of protein restriction on the progression of the established adriamycin-induced nephropathy, and whether the protective effect of the diet persists after the diet is discontinued. The effect of a low protein diet (LPD) was studied for 6 weeks in protocol 1, 16 weeks in protocol 2 and for 28 weeks in protocol 3. In protocol 3, one group (LL) received LPD and another (NN) was given a normal protein diet (NPD). A third group (LN) received LPD for 16 weeks and then NPD for 12 weeks and a fourth group (NL) was fed NPD for 16 weeks and then LPD for 12 weeks. In protocol 1 the tubulo-interstitial index (TILI) of rats on LPD (Md = 2, P25 = 0.0; P75 = 3.5) after six weeks, was smaller than that of the animals on NPD (Md = 6.0; P25 = 3.0; P75 = 8.0; p < 0.05). In protocol 2, the group taking LPD presented an area of interstitial fibrosis (IF) (Md = 0.5%, P25 0.2%; P75 = 1.9%) smaller than that of the NPD group (Md = 6.8%; P25 = 5.2%; P75 = 7.1%; p < 0.05). No significant difference in the area of glomerulosclerosis (GSA) was observed between the animals on LPD (Md = 0.0%; P25 = 0.0%, P75 = 0.0%) and NPD (Md = 0.37%; P25 = 02%, P75 = 1.25%; p > 0.05). In protocol 3, the group LL showed GSA (Md = 1.3%; P25 0.6%, P75 = 2.5%) and IF (Md = 3.6%; P25 = 1.6%; P75 = 5.9%) smaller that those of LN (GSA Md = 10.1%; P25 = 6.6%; P75 = 14.8%; IF: Md = 17.3%; P25 = 14.1%; P75 = 24.5%), NL (GSA: Md = 9.1%; P25 = 5.8%; P75 = 11.7%; IF: Md = 25.0%; P25 = 20.4%; P75 = 30%), and NN (GSA: Md = 6.75%; P25 = 4.9%; P75 = 11.7%; IF: Md = 20.9%; P25 = 16.2%; P75 = 32.4%). In conclusion, in order to be effective, LPD must be introduced early and maintained for a long period of tune.

Microbiological epidemiological history of meningococcal disease in Rio de Janeiro, Brazil

The main objectives of the present study were to investigate the clinical and laboratory features of meningococcal disease in the city of Rio de Janeiro, Brazil, during the overlap of 2 epidemics in the 1990s. We conducted a study of a series of cases of meningococcal disease admitted in a Meningitis Reference Hospital. All clinical isolates available were analyzed by means of microbiological epidemiological markers. In 1990, Neisseria meningitidis serogroup B:4,7:P1.19,15, 1.7,1 sulfadiazine-resistant of the ET-5 complex emerged causing epidemic disease. Despite mass vaccination campaign (VaMengoc B+C®), the ET-5 clone remained hyperendemic after the epidemic peaked. In 1993 to 1995, an epidemic of serogroup C belonged to the cluster A4 overlapped, with a significant shift in the age distribution toward older age groups and an increase of sepsis. Serogroup C epidemics are a recurrent problem in Rio de Janeiro, which can be hindered with the introduction of a conjugate vaccine. We hope the data presented here brings useful information to discuss vaccines strategies and early management of suspected cases.