Human-->mouse radiation chimera do not develop Epstein-Barr virus lymphoma

It has been shown that engraftment of human peripheral blood lymphocytes (PBL) from Epstein-Barr virus (EBV) seropositive donors in C.B-17/SCID mice is associated with a high incidence of human B cell tumors. More recently, we described a new approach enabling engraftment of human PBL in normal strains of mice or rats receiving lethal split-dose radiation and radioprotected with SCID bone marrow. We now demonstrate that, in contrast to SCID recipients of human PBL, Balb/c and C3H/HeJ recipients of 50-100 x 10(6) human PBL did not develop any EBV lymphoma during a 7-month follow-up period, but were successfully engrafted with human B and T cells. On the other hand, lymphoma developed in 90% of the C.B-17/SCID mice infused with 70 x 10(6) human PBL from the same donor. Likewise, 36% of beige/nude/xid (BNX) mice, exposed to 12 Gy TBI, radioprotected with SCID bone marrow and then transplanted with human PBL developed lymphoma. Similar results were obtained when different strains were infused with PBL of the same donor. Immunohistochemical analysis indicated that the tumor cells were of human B cell origin and expressed the EBV-encoded latent membrane protein-1 and nuclear antigen 2. While further studies are required to understand the mechanisms which suppressed outgrowth of EBV lymphoma in human --> mouse radiation chimera, compared to human --> C.B-17/SCID or human --> BNX chimera, this marked resistance offers new possibilities for transplantation of hematopoietic tissues or cells from EBV-positive donors.

Unconjugated estriol as maternal serum marker for the detection of Down syndrome pregnancies

The effectiveness of unconjugated estriol (uE3) as a serum marker for the detection of Down syndrome (DS) during the 2nd trimester of pregnancy was evaluated. A population of 18,764 normal singleton pregnancies was screened for alpha-feto-protein and human chorionic gonadotropin. In 9,311 women, uE3 was added. Using a risk of 1:250 at term as a cutoff value, the false-positive rates were 4.1 and 4.3% without and with uE3, respectively. The detection rates in 47 DS serum samples, some of which were studied retrospectively, were 66% without uE3 and 57% with uE3. In 12 of 25 younger women and in 19 of 22 older women, DS was detected without uE3. The uE3 contributed to the detection of 4 additional DS pregnancies (1 in the young and 3 in older women). On the other hand, 8 DS pregnancies (3 in younger women and 5 in older women) escaped detection. In our sample the addition of uE3 lowered the detection rate of DS pregnancies with only a small and insignificant effect on the false-positive rate. Our results call for special caution in the addition of markers for risk calculations. We suggest that pregnancies with a calculated risk of > 1:250 following maternal serum alpha-fetoprotein and human chorionic gonadotropin markers tests should be regarded as high-risk pregnancies, even in cases in whom the addition of uE3 lowers the risk beneath the cutoff value.

Preassociation of STAT1 with STAT2 and STAT3 in separate signalling complexes prior to cytokine stimulation

A variety of cytokines and growth factors act through an induction of gene expression mediated by a family of latent transcription factors called STAT (signal transducers and activators of transcription) proteins. Ligand-induced tyrosine phosphorylation of the STATs promotes their homodimer and heterodimer formation and subsequent nuclear translocation. We demonstrate here that STAT protein heterocomplexes exist prior to cytokine treatment. When unstimulated HeLa cells are ruptured in hypotonic buffer without salt or detergent, immunoadsorption of either STAT1 or STAT2 from the resulting cytosol yields coimmunoadsorption of the other STAT protein. Similarly, STAT1-STAT3 heterocomplexes are coimmunoadsorbed from hypotonic cytosol. STAT1 and STAT2 or STAT1 and STAT3 translated in reticulocyte lysate spontaneously form heterocomplexes when the translation lysates are mixed at 0 degrees C. Our data suggest that interferon-alpha /beta-induced tyrosine phosphorylation increases the stability of a preexisting, latent, STAT1-STAT2 signaling complex. Newly translated STAT1 binds in equilibrium fashion to STAT2 and STAT3, but we show that STAT2 and STAT3 exist in separate heterocomplexes with STAT1, consistent with a model in which STAT1 contains a common binding site for other STAT proteins.

[Emergency angioplasty for total thrombosis of the left main coronary artery. Apropos of a case]

Complete thrombosis of the left main coronary artery is a rare angiographic finding and usually gives rise to cardiogenic shock during unstable angina or myocardial infarction. The prognosis of this condition is very dependent on the collateral coronary circulation and the myocardial protection seems to depend on the rapidity of revascularisation. Two therapeutic approaches may be envisaged; emergency coronary bypass grafting or percutaneous angioplasty, the natural history being particularly disastrous. The authors report the case of a 42-year-old patient with complete occlusion of the left main stem responsible for unstable angina and acute pulmonary oedema. The outcome with angioplasty in the acute phase associated with surgical revascularisation four days later, was good.

Maternal serum markers levels in consecutive pregnancies: a possible genetic predisposition to abnormal levels

The study comprised 2,361 women, each with two consecutive normal uncomplicated pregnancies screened at 15-20 weeks gestation for maternal serum alpha-fetoprotein levels (AFP). In 1,816 of these women, maternal serum human chorionic gonadotropin (hCG) levels were tested as well. The proportion of women who had a second high AFP level (> or = 2.0 MOM) in their subsequent pregnancy was 6.5-fold higher as compared with the proportion of women who had normal levels of AFP in their first tested pregnancy. The relative chance of having a second positive result of a low level of AFP (AFP < or = 0.5 MOM) in subsequent pregnancies was 3.8-fold higher. The relative chances of having a second positive result of high or low levels of hCG were 3.9- and 2.2-fold higher, respectively. It is concluded that there is a predisposition for abnormal levels of serum markers that is influenced by genetic and/or environmental factors. Therefore it is suggested that the individual's risk of having a Down syndrome baby, or other adverse pregnancy outcome that is derived from the serum markers' levels, should be adjusted taking into account unexplained high or low levels in previous pregnancies. A screening policy is suggested which is designed to yield a lower false-positive rate without affecting the detection rate of abnormal pregnancies. More data are needed before an accurate adjustment based on previous results can be made.

Effects of cyclosporin and cremophor on working rat heart and incidence of myocardial lipid peroxidation

Cyclosporin A (CsA) is widely used as the immunosuppressant of choice for preventing graft rejection. However, its clinical use is hampered by certain side effects, especially its nephrotoxicity and other cardiovascular side effects. CsA for intravenous infusion contains cremophor (Cre) and this vehicle has significant adverse effects on endothelial function and vascular muscle. The present study was aimed at investigating the direct effects of CsA and Cre on isolated and perfused rat hearts in the dosage that closely approximates the peak level achieved for the prevention of graft rejection in the rat. Transplantation is a clinical setting in which the myocardium may be exposed to transient ischemia. In this study, we have shown that the vehicle of CsA, namely Cre, has significant adverse effects on cardiac function. We observed a reduction in coronary flow and aortic output. Addition of CsA appeared to induce a further reduction of aortic flow. We have also shown that a significant increase of thiobarbituric acid reactive substances, considered as an index of lipid peroxidation, occurred in the reperfused heart in the presence of Cre+CsA. Our experimental study shows that Cre turned out to be toxic to myocardium by itself. In the heart, potential Cre-CsA interactions possibly potentiating CsA toxicity could not be excluded. The increase of lipid peroxidation in the heart perfused with CsA suggests that reactive oxygen species may be involved in the detrimental effects of this substance on the heart.

Susceptibility of llamas (Lama glama) to infection with foot-and-mouth-disease virus

An experimental trial was conducted to evaluate the ability of foot-and-mouth-disease (FMD) virus (serotypes A79, C3, O1) to infect susceptible llamas exposed either directly to affected livestock, or indirectly to llamas that had been directly exposed to affected livestock. In addition, susceptible livestock species (cattle, pigs, goats, and sheep) were exposed to those llamas that had been both directly and indirectly exposed to the FMD virus to further look at potential transmission possibilities. Of 30 llamas directly exposed to the FMD virus, only three (3/30) showed evidence of infection, and of those, only two (2/30) had mild clinical signs. No FMD virus was isolated from either oesophageal-pharyngeal (OP) fluid or blood samples collected from the infected llamas beyond 14 days post-exposure. There was no evidence of virus transmission between the directly exposed and indirectly exposed llamas or between both groups of llamas and susceptible domestic livestock, as determined by the lack of clinical signs, by virus isolation, and by serology results. These results provide further evidence that llamas are resistant to FMD infection, and that they play a minor role, if any, in transmitting the virus to domestic livestock.

Differential regulation of the alpha/beta interferon-stimulated Jak/Stat pathway by the SH2 domain-containing tyrosine phosphatase SHPTP1

Interferons (IFNs) induce early-response genes by stimulating Janus family (Jak) tyrosine kinases, leading to tyrosine phosphorylation of Stat transcription factors. Previous studies implicated protein-tyrosine phosphatase (PTP) activity in the control of IFN-regulated Jak/Stat signaling, but the specific PTPs responsible remained unidentified. We have found that SH2 domain-containing PTP1 (SHPTP1; also called PTP1C, HCP, or SHP) reversibly associates with the IFN-alpha receptor complex upon IFN addition. Compared with macrophages from normal littermate controls, macrophages from motheaten mice, which lack SHPTP1, show dramatically increased Jak1 and Stat1 alpha tyrosine phosphorylation, whereas Tyk2 and Stat2 activation is largely unaffected. These findings correlate with selectively increased complex formation on a gamma response element, but not an IFN-stimulated response element, in motheaten macrophages. Our results establish that SHPTP1 selectively regulates distinct components of Jak/Stat signal transduction pathways in vivo.

Aortic valve regurgitation caused by blunt chest injury

Aortic valve regurgitation is an uncommon consequence of closed chest injury. It is caused by damage to the valve apparatus (ruptured cusp) or when subadventitial rupture of the ascending aorta causes prolapse of a subjacent valve cusp. Aortic valve regurgitation was detected in 4 patients (2 men and 2 women, 30 to 65 years old) who had sustained multiple injuries in road accidents 1 week to 30 years before. Three had subadventitial rupture of the ascending aorta and one had isolated rupture of the noncoronary cusp of the aortic valve. The mechanism responsible for the damage was believed to be a consequence of multiple chest lesions (right costal flap, sternal fracture, pulmonary contusion). It is difficult to diagnose and treat aortic regurgitation in patients with multiple injuries. Three patients had repair operations and the remaining patient needed valve replacement. If aortic regurgitation is haemodynamically well tolerated, the operation should be postponed until the patients have recovered from their other injuries. The results in these 4 patients and in other reported cases indicate that operations can be performed soon after the acute phase.

Conversion of normal rats into SCID-like animals by means of bone marrow transplantation from SCID donors allows engraftment of human peripheral blood mononuclear cells

We have recently shown that lethally irradiated normal strains of mice, radioprotected with SCID bone marrow, can be engrafted with human peripheral blood mononuclear cells (PBMC). We now demonstrate that lethally irradiated Lewis rats can also be radioprotected with a transplant of SCID bone marrow cells, administered 1 day after total body irradiation. Split chimerism was found in PBMC, 30 days after transplantation, with predominance of SCID donor-type cells. The average percentages of CD4 and CD8 T cells, of mouse or rat origin, were < 1%. This chimerism status could be maintained for over 3 months. When human PBMC (300-1000 x 10(6) cells) were transplanted intraperitoneally 1 day after the administration of SCID bone marrow, prompt engraftment of human CD4 and human CD8 T cells, as well as human CD20 B cells, was found in the peritoneum and in internal organ (such as liver, lung, spleen, thymus, and lymph nodes). T cell activation was high: about 50% of the cells expressed HLA-DR and almost all expressed CD45RO. High titers of human Ig (> 1 mg/ml) were initially found after 2 weeks; these levels were similar to those found in the irradiated mouse model and in the SCID model. Likewise, marked human anti-tetanus response, predominantly of the IgG type, was recorded 2 weeks after the immunization, reaching maximal levels at 4 weeks. The triple-chimeric SCID-like rats, which accept as much as 1000 x 10(6) human PBMC, can potentially be used to elicit both antibody responses and T cell responses against specific antigens, with the advantages of a larger animal.

Amniocentesis rate and the detection of Down syndrome and other chromosomal anomalies in Israel

We investigated the contribution of different screening criteria to the prenatal detection of Down syndrome (DS) as well as other chromosomal anomalies in the Jewish population in Israel during 1990 and 1992. There was a significant decrease (P < 0.03) in the incidence of DS live-births during 1992 (40:78 442) compared with 1990 (69:73 751) which paralleled a marked increase in total prenatal testing and in DS cases detected prenatally. Private laboratories, which perform amniocenteses mostly for women with a low risk of DS and without genetic counselling, had a significantly lower detection rate (1:917) compared with that of the genetic institutes, which following genetic counselling test both women > or = 37 years of age (1:91) and women younger than 37 years (1:113). The detection of chromosomal anomalies other than DS was less affected by the reason for amniocentesis. Amniocentesis indicated by maternal serum marker screening of women younger than 37 years identified a greater number of chromosomal anomalies other than DS than amniocentesis based on age (> or = 37 years) alone (111:9604 versus 94:9810; P < 0.06). Prenatal detection of DS is most effective when the indication for amniocentesis follows genetic counselling. The increasing use of maternal serum marker screening leads to a significant improvement in the positive detection rate of chromosomal anomalies other than DS in young women.

Replacement therapy with a monoclonal antibody purified protein C concentrate in newborns with severe congenital protein C deficiency

Protein C replacement therapy with a monoclonal antibody purified, virus inactivated protein C concentrate was carried out in nine infants (three male, six female) with severe congenital protein C deficiency and life-threatening purpura fulminans and/or thrombosis associated with disseminated intravascular coagulation (DIC). Eight infants were homozygous for protein C deficiency; one was a compound heterozygote. The treatment period varied from 22 days to three years. The half-life of protein C was found to be as short as two to three hours during activation of the coagulation system, increasing to approximately ten hours after stabilization. During the acute phase, protein C levels of 0.10 to 0.25 IU/mL were associated with elevated markers of coagulation activation indicating DIC, while protein C levels greater than 0.25 were associated with normalization of coagulation markers. No product-related side effects were reported. Episodes of bleeding or purpura recurred in all patients who were switched to oral anticoagulant therapy, necessitating reinstatement of protein C replacement therapy, either as needed to control symptoms, or on a long-term prophylactic schedule, alone or in addition to oral anticoagulation. Home treatment with protein C concentrate allowed a near-normal life-style for patients who otherwise would be hospitalized for long periods of time.

Requirement for MAP kinase (ERK2) activity in interferon alpha- and interferon beta-stimulated gene expression through STAT proteins

Activation of early response genes by interferons (IFNs) requires tyrosine phosphorylation of STAT (signal transducers and activators of transcription) proteins. It was found that the serine-threonine kinase mitogen-activated protein kinase (MAPK) [specifically, the 42-kilodalton MAPK or extracellular signal-regulated kinase 2 (ERK2)] interacted with the alpha subunit of IFN-alpha/beta receptor in vitro and in vivo. Treatment of cells with IFN-beta induced tyrosine phosphorylation and activation of MAPK and caused MAPK and Stat1 alpha to coimmunoprecipitate. Furthermore, expression of dominant negative MAPK inhibited IFN-beta-induced transcription. Therefore, MAPK appears to regulate IFN-alpha and IFN-beta activation of early response genes by modifying the Jak-STAT signaling cascade.

[Occurrence of suspicious changes in cervix cytology in women after liver transplantation]

After transplantation the necessary immunosuppressive therapy predisposes to the development of de novo cancers. From January 1989 to April 1994 we collected PAR smears of 98 women before and repeatedly after liver transplantation. After surgery all women received as immunosuppressive agents either Cyclosporin A or FK 506 as long-term medication. In seven patients (8.5%) who had a normal cervical cytology before transplantation a suspicious PAP smear was found on average 11 months after transplantation. In five cases a histological verification (exploratory excision, coning of the cervix) was made. In two cases we found a CIN III. Possible causes for the higher incidence of dysplasia of the cervix observed in the transplant patients are discussed. Similar to kidney transplant recipients female liver transplant recipients are at higher risk of developing cervical dysplasias and neoplasias. Accelerated development of malignancy seems likely. The influence on the cervical cells of both immunosuppressive drugs Cyclosporin A and FK 506 seems to be of a similar nature. Recommendations for the gynaecological care of female liver transplant recipients treated with immunosuppressive therapy are given.

Nonsalt-losing male pseudohermaphroditism due to the novel homozygous N100S mutation in the type II 3 beta-hydroxysteroid dehydrogenase gene

Recently, the structure of two genes encoding isoenzymes responsible for 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta HSD) activity in the human was elucidated. This activity is an essential step in the biosynthesis of all classes of steroid hormones. In the classic severe form of 3 beta HSD deficiency, patients present with adrenal insufficiency, various degrees of salt loss, and incomplete masculinization in males. Here we report the characterization of the molecular basis of congenital adrenal hyperplasia due to 3 beta HSD deficiency in a male pseudohermaphrodite born from consanguineous parents and having no clinical salt loss. To analyze the structure of the type I and II 3 beta HSD genes of the patient, DNA fragments, generated by polymerase chain reaction amplification of the four exons and the exon-intron boundaries of these genes, were directly sequenced. The patients carried a homozygous missense mutation converting Asn100 to Ser in exon 3 of his type II 3 beta HSD gene. His parents were heterozygous for the same point mutation. The absence of clinical salt loss associated with a male pseudohermaphroditism suggested that 3 beta HSD activity was impaired to different levels in the testes and adrenal. To elucidate whether this N100S missense mutation affected preferentially a steroidogenic pathway, enzymatic activity was analyzed by in vitro analysis of mutant recombinant enzyme generated by site-directed mutagenesis after its transient expression in COS-1 cells. Using homogenates from transfected cells, the N100S 3 beta HSD enzyme showed a Km value for pregnenolone of 25 +/- 3 mumol/L compared with 3.5 +/- 0.2 mumol/L for the normal human type II 3 beta HSD enzyme. Similar results were obtained using dehydroepiandrosterone as substrate. In addition to decreasing apparent affinity, the N100S mutation decreased the relative specific activity (Vmax), leading to a relative specificity (relative Vmax/Km) 2.7% and 11% that of normal type II 3 beta HSD using pregnenolone or dehydroepiandrosterone as substrate, respectively. Moreover, the mutant N100S protein had an apparent decreased affinity for NAD+, with a Km value of 650 +/- 66 mumol/L compared with 20 +/- 2 mumol/L for normal type II 3 beta HSD. Except for the hypothetical effect of local factors, these findings suggest that a very weak residual activity of the normal type II 3 beta HSD enzyme could prevent salt loss, but it was insufficient for normal male sex differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Human/mouse radiation chimera are capable of mounting a human primary humoral response

Lubin et al recently described a new approach that enables the generation of human/mouse chimera by adoptive transfer of human peripheral blood mononuclear cells (PBMC) into lethally irradiated normal strains of mice, radioprotected with bone marrow (BM) from donors with severe combined immune deficiency (SCID). In the present study, we demonstrate in such human/mouse chimera a marked humoral response to recall antigen, such as tetanus toxoid (TT) or hepatitis B surface antigen (HBsAg), as well as a significant primary response to keyhole limpet hemocyanin (KLH). Maximal anti-KLH response in human/Balb chimera was attained 2 to 4 weeks after the immunization and declined thereafter. One week after transplantation, the predominant anti-KLH subtype was IgM, while after 2 weeks, the dominance had shifted to IgG. Similar primary antibody response was also demonstrated against the human immunodeficiency virus (HIV) Nef protein. Comparison between human/Balb and human/SCID chimera showed a major difference in their ability to mount a primary response against KLH. In Balb/c recipients, more than half of the mice exhibited marked IgM titers against KLH, while there was hardly any anti-KLH IgM response in the SCID recipients. From the earliest time point onwards, when anti-KLH antibodies were found in the latter chimera, they were predominantly of the IgG type. We have previously shown that in human/Balb chimera, unlike in SCID recipients, dissemination of transplanted PBMC into the spleen and other internal organs occurs within 24 hours. Therefore, it is likely that the early seeding in the appropriate microenvironment of the lymphoid tissues, is crucial for the maintenance of virgin human B cells.

Adrenarche does not occur in treated patients with congenital adrenal hyperplasia resulting from 21-hydroxylase deficiency

OBJECTIVE

There have been few studies of adrenarche in patients with congenital adrenal hyperplasia (CAH). We have therefore sought to detect the onset of adrenarche in CAH patients and to investigate whether its evolution was influenced by the severity of the disease, the age at the onset of substitution therapy, or both.

DESIGN AND PATIENTS

Sixteen female CAH patients were studied longitudinally for 4-11 years. They were all given substitution therapy and treatments were well controlled as judged by repeated hormonal evaluations. The patients were divided into two groups: group A consisted of 10 girls with a severe classic (congenital) form, while group B included 6 girls presenting with a non-classic form.

MEASUREMENTS

Circulating levels of dehydroepiandrosterone sulphate (DHEAS), were determined as an indicator of adrenarche. Hormonal assessments included measurements of 17-hydroxyprogesterone (17-OHP), testosterone, ACTH and plasma renin activity. All were estimated by conventional specific assays.

RESULTS

Mean levels were analysed in consecutive two-year age periods. In group A, DHEAS levels were significantly lower at any age than in control subjects, and lower than in patients with non-classic CAH. DHEAS levels showed no increment with age. In group B, plasma DHEAS levels were surprisingly high for the age at the time of diagnosis, declining gradually on substitution therapy, although they remained somewhat higher than in group A.

CONCLUSIONS

The high DHEAS levels observed in untreated girls of group B are probably the result of chronic hypersecretion of ACTH. Under well controlled, non-suppressive substitution therapy, patients with congenital adrenal hyperplasia showed no rise in DHEAS levels at the physiological age of adrenarche whatever the degree of the enzyme defect and whatever the age at onset of therapy.

Treatment of purpura fulminans in meningococcemia with protein C concentrate

OBJECTIVE

To evaluate the clinical and laboratory effects of protein C concentrate as an adjunct to conventional therapy in the treatment of meningococcemia with purpura fulminans.

DESIGN

Case series (pilot study).

SETTING

Intensive care unit in a tertiary care pediatric hospital.

PATIENTS

Four children (aged 3 months to 15 years) requiring intensive treatment for meningococcemia with shock, disseminated intravascular coagulation, and purpura fulminans.

INTERVENTION

Intravenous administration of a protein C concentrate (100 IU/kg every 6 hours).

MAIN OUTCOME MEASURES

Plasma protein C amidolytic activity, fibrinogen, and D-dimers; evolution of skin and limb lesions.

RESULTS

Treatment with protein C concentrate led to a rise in plasma protein C activity levels to within normal limits in all patients, associated with an increase in plasma fibrinogen and a bimodal decrease in D-dimers. No adverse effects were noted. All patients had reversal of organ dysfunction despite the severity of the initial illness. Two patients recovered completely with no sequelae; two required amputations.

CONCLUSIONS

These encouraging clinical and laboratory results and the absence of side effects warrant the initiation of a double-blind, randomized controlled multicenter trial to determine the role of protein C replacement in the treatment of meningococcemia-associated purpura fulminans.

Flow cytometric DNA analysis of classic and steroid-induced Kaposi's sarcoma

Flow cytometric DNA analysis of various tumours has indicated a correlation between the degree of malignancy and ploidy; results which could have clinical significance. We analysed the ploidy of Kaposi's sarcoma (KS) tumours, and classified the results according to clinical history and histological findings. We found that patients on steroid treatment had an aneuploid pattern, and most of the patients with classic-type KS had a diploid pattern on flow cytometry.