Predicting Passive Permeability of Drug-like Molecules from Chemical Structure: Where Are We?

Intestinal absorption in human is routinely predicted in drug discovery using in vitro assays such as permeability in the Madin-Darby canine kidney cell line. In silico models trained on these data are used in drug discovery efforts to prioritize novel chemical targets for synthesis; however, their proprietary nature and the limited validation available, which is usually restricted to predicting in vitro permeability, are barriers to widespread adoption. Because of the categorical nature of the in vitro permeability assay, intrinsic assay variability, and the challenges often encountered when translating in vitro data to an in vivo drug property, validation based solely on in vitro data might not be a good characterization of the usefulness of the in silico tool. In this work, we analyze the performance of three different in silico models in predicting the in vitro and in vivo permeability of 300 marketed drugs and 86 discovery compounds. The models differ in their approach (mechanistic vs quantitative structure-activity relationship) and the degree of complexity; one of them is a linear equation based on seven simple physicochemical descriptors and is presented for the first time in this work. Results show that in silico models can be successfully used to complement the discovery toolbox for characterizing in vivo intestinal permeability, defined using fraction of dose absorbed in human (Fa) and human jejunal permeability (P_eff). While the in vitro permeability models outperformed the in silico approach at predicting each of the in vivo end points explored, the gap in predictivity between the in vitro and the in vivo data was generally comparable to the gap between in silico and in vitro data. The in vitro and in silico approaches shared many of the same outliers, which can often be explained by the route of drug absorption (paracellular vs transcellular, active vs passive). Data suggest that the discovery process can greatly benefit from an early adoption of in silico models for predicting permeability as well as from a careful analysis of the in silico to in vivo disconnects.

The Pathology of Aging 129S6/SvEvTac Mice

The 129 mouse strain is commonly used for the generation of genetically engineered mice. Genetic drift or accidental contamination during outcrossing has resulted in several 129 substrains. Comprehensive data on spontaneous age-related pathology exist for the 129S4/SvJae substrain, whereas only limited information is available for other 129 substrains. This longitudinal aging study describes the life span and spontaneous lesions of 44 male and 18 female mice of the 129S6/SvEvTac substrain. Median survival time was 778 and 770 days for males and females, respectively. Tumors of lung and Harderian gland were the most common neoplasms in both sexes. Hepatocellular tumors occurred mainly in males. Hematopoietic tumors were observed at low frequency. Suppurative and ulcerative blepharoconjunctivitis was the most common nonneoplastic condition in both sexes. Corynebacteria (primarily Corynebacterium urealyticum and C. pseudodiphtheriticum) were isolated from animals with blepharoconjunctivitis and in some cases from unaffected mice, although a clear causal association between corynebacterial infections and blepharoconjunctivitis could not be inferred. Polyarteritis occurred only in males and was identified as the most common nonneoplastic contributory cause of death. Eosinophilic crystalline pneumonia occurred in both sexes and was a relevant cause of death or comorbidity. Epithelial hyalinosis at extrapulmonary sites was noted at higher frequency in females. This study contributes important data on the spontaneous age-related pathology of the 129S6/SvEvTac mouse substrain and is a valuable reference for evaluation of the phenotype in genetically engineered mice obtained with this 129 substrain.

Pathologic and Environmental Studies Provide New Pathogenetic Insights Into Ringtail of Laboratory Mice

Ringtail is a pathologic condition of laboratory rodents characterized by annular constrictions of the tail. Traditionally, it is classified as an environmental disorder caused by low relative humidity, but other factors (temperature, dietary deficiencies, genetic susceptibility, and caging type) have also been proposed. Twenty litters of mice with ringtail lesions occurred from September 2010 to August 2013 in a facility located in the northern Italy. Mice were maintained under controlled environmental conditions and fed a standard diet. Retrospective analysis of environmental data (relative humidity, temperature) was carried out. Gross, histopathologic, scanning, and transmission electron microscopy examination of tails and limbs was performed. The incidence of ringtail was 0.075% (20/26 800) of all weaned litters over the 3-year period of examination. Temperature and relative humidity remained within accepted limits in all cases except one. We observed annular constrictions in tail, digits of pes, crus, and antebrachium in 116 (100.0%), 47 (40.5%), 11 (9.5%), and 2 (1.7%) of 116 affected mice, respectively. Histologic and ultrastructural examination revealed abnormal keratin desquamation and presence of a keratin ring encircling the tail, causing progressive strangulation of the growing tail with subsequent compression and ulceration of underlying soft tissues, resulting in circulatory changes (edema, hyperemia, thrombosis, hemorrhages), ischemic necrosis, and eventually auto-amputation distal to the constriction. On the basis of our findings, we suggest a disorder of cornification as the primary lesion of ringtail in mice. The cause of these cases, however, remained undetermined, even though traditional etiologic factors (relative humidity, temperature, diet, caging type) were reasonably excluded.

Diffuse Scaling Dermatitis in an Athymic Nude Mouse

This report describes the clinicopathological features of a case of diffuse scaling dermatitis that occurred in a 16-week-old female athymic nude (CrTac:NCr- Foxn1nu) mouse. Gross presentation was suggestive of Corynebacterium bovis infection (scaly skin disease). However, C. bovis was not isolated from the skin of the affected animal or from the skin of unaffected CrTac:NCr- Foxn1nu mice housed in the same cage or room. Staphylococcus xylosus was instead isolated in high numbers from the skin lesion, whereas only a few colonies were recovered from the skin of unaffected mice. Microscopically, the affected skin was characterized by chronic hyperplastic and hyperkeratotic dermatitis with focal ulcerations, extensive serocellular crusts, and intralesional clusters of Gram-positive coccoid bacteria. Although gross presentation of the reported case was suggestive of C. bovis infection, epidemiological, histopathological, and bacteriological findings definitively ruled out an outbreak of scaly skin disease. A diagnostic hypothesis of hyperplastic and hyperkeratotic dermatitis associated with opportunistic S. xylosus infection was formulated based on increased bacterial burden and presence of intralesional Gram-positive coccoid bacteria.

Immunohistochemical detection of Ym1/Ym2 chitinase-like lectins associated with hyalinosis and polypoid adenomas of the transitional epithelium in a mouse with acute myeloid leukemia

An 8-month-old PML/RARalpha knock-in female mouse developed a promyelocytic-like myeloid leukemia with an expected latency. At necropsy, besides the typical findings associated with myeloid leukemia, a severe unilateral hydronephrosis was observed. By histopathologic examination, 2 polypoid adenomas arising from the transitional epithelium of the renal pelvis and ureter were detected. The epithelial cells of the polypoid adenomas showed accumulation of hyaline eosinophilic material within the cytoplasm. Large amounts of extracellular eosinophilic crystals were also associated with the transitional cell adenomas. Immunohistochemical analysis revealed that the eosinophilic intracytoplasmic material and the extracellular eosinophilic crystals were composed of Ym proteins. A unilateral hyaline droplet tubular nephropathy was associated with the myeloid leukemia. Expression of Ym proteins characterized both the neoplastic myeloid infiltrates and the tubular hyaline droplets. In the present PML/RARalpha knock-in female mouse, the accumulation of Ym proteins associated with the myeloid leukemia and with the polypoid adenomas of the transitional epithelium underlies 2 distinct pathogenetic mechanisms.

Energetics of midvelocity emissions in peripheral heavy ion collisions at Fermi energies

Peripheral and semiperipheral collisions have been studied in the system 93Nb+93Nb at 38A MeV. The evaporative and midvelocity components of the light charged particle and intermediate mass fragment emissions have been carefully disentangled. In this way it was possible to obtain the average amount not only of charge and mass, but also of energy, pertaining to the midvelocity emission, as a function of an impact parameter estimator. This emission has a very important role in the overall balance of the reaction, as it accounts for a large fraction of the emitted mass and for more than half of the dissipated energy. As such, it may give precious clues on the microscopic mechanism of energy transport from the interaction zone toward the target and projectile remnants.

Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.

Eosinophilic crystals as a distinctive morphologic feature of a hyaline droplet nephropathy in a mouse model of acute myelogenous leukaemia

Eosinophilic crystals have been described in the upper and lower respiratory tract, gall bladder, intrahepatic bile ducts and glandular stomach of different laboratory mice strains. They have been recently identified as chitinase-like (Ym1/Ym2) proteins. Here we describe the occurrence of eosinophilic crystals in the renal tubules of mice with experimentally induced acute myelogenous leukaemia. Fourteen FVB/N and 29 129Sv mice of both sexes, 8-10 weeks of age, were employed to establish a model of human acute myelogenous leukaemia. Nine mice that developed a widespread acute myelogenous leukaemia revealed the presence of eosinophilic crystals in renal tubules. The presence of eosinophilic crystals in the kidneys was constantly associated with a hyaline droplet nephropathy. Immunohistochemistry showed that the crystals and the hyaline droplets were composed of chitinase-like (Ym1/Ym2) proteins. Furthermore, immunoreactivity for Ym1/Ym2 proteins was also detected in the crystalline material stored in the cytoplasm of large macrophage-like cells or in extracellular localization within the leukaemic infiltrates. On the basis of our results we hypothesize that the detection of the Ym1/Ym2 proteins in the urine of mice might represent a feasible indicator of the burden and progression of the leukaemic condition in our murine model.

Kinetics and viability of circulating endothelial cells as surrogate angiogenesis marker in an animal model of human lymphoma

Circulating endothelial cells (CECs) were evaluated by flow cytometry in immunodeficient mice bearing human lymphoma. A trend toward higher CEC values was observed on days 7 and 14 after transplant, and differences versus controls were highly significant on day 21 (P = 0.0061). A strong correlation was found between CEC and tumor volume (r, 0.942; P = 0.004) and between CEC and tumor-generated VEGF (r, 0.669; P = 0.02). In mice given cyclophosphamide, most of the circulating apoptotic cells were hematopoietic and not endothelial. Conversely, in mice given endostatin, all of the increase in apoptotic cells was in the endothelial cell compartment. CEC evaluation is promising as a noninvasive, surrogate angiogenesis marker.

Real-time quantitative PCR for human herpesvirus 6 DNA

The diagnosis of human herpesvirus 6 (HHV-6) infection represents a complex issue because the most widely used diagnostic tools, such as immunoglobulin G antibody titer determination and qualitative DNA PCR with blood cells, are unable to distinguish between latent (clinically silent) and active (often clinically relevant) infection. We have developed a new, highly sensitive, quantitative PCR assay for the accurate measurement of HHV-6 DNA in tissue-derived cell suspensions and body fluids. The test uses a 5' nuclease, fluorogenic assay combined with real-time detection of PCR amplification products with the ABI PRISM 7700 sequence detector system. The sensitivity of this method is equal to the sensitivity of a nested PCR protocol (lower detection limit, 1 viral genome equivalent/test) for both the A and the B HHV-6 subgroups and shows a wider dynamic range of detection (from 1 to 10(6) viral genome equivalents/test) and a higher degree of accuracy, repeatability, and reproducibility compared to those of a standard quantitative-competitive PCR assay developed with the same reference DNA molecule. The novel technique is versatile, showing the same sensitivity and dynamic range with viral DNA extracted from different fluids (i.e., culture medium or plasma) or from tissue-derived cell suspensions. Furthermore, by virtue of its high-throughput format, this method is well suited for large epidemiological surveys.

Ringtail in suckling Munich Wistar Fromter rats: a histopathologic study

Ringtail is a pathologic condition of the tail of rats and other rodents that is traditionally attributed to low environmental humidity, although dietary deficiencies, genetic susceptibility, environmental temperature, and degree of hydration of the animal also have been suggested as possible causes. To the authors' knowledge, a detailed histopathologic study that may serve to shed light on the etiopathogenesis of this disease has not yet been published. We describe the histologic findings of ringtail observed in 12 suckling Munich Wistar Fromter (MWF) rats from two litters. Epidermal hyperplasia characterized by orthokeratotic and parakeratotic hyperkeratosis and acanthosis was observed in all affected rats. Numerous often dilated vessels were present in the dermis of tails that appeared of red/brown color at gross examination. In severe cases, the dilated vascular structures were thrombotic and accompanied by dermal hemorrhages and focal coagulative necrosis of the overlying epidermis. These findings suggest that epidermal acanthosis and hyperkeratosis are the main and primary events in the development of ringtail. To clarify the cause of this disease, future studies should be focused on the numerous factors that can induce such epidermal changes.

Coinfection of SCID-hu Thy/Liv mice with human herpesvirus 6 and human immunodeficiency virus type 1

Human herpesvirus 6 (HHV-6) has been proposed as a potential cofactor in the progression of human immunodeficiency virus type 1 (HIV-1) disease. We used the SCID-hu Thy/Liv mouse model to evaluate the in vivo interactions between HHV-6 and HIV-1. Our results demonstrate that HHV-6 and HIV-1 can simultaneously replicate in the human thymus in vivo. In this model, however, the presence of one virus appears not to modify the replication or cytopathicity of the other.

The thin red line: angiogenesis in normal and malignant hematopoiesis

This review describes the current knowledge about cell subsets involved in vasculogenesis (i.e., differentiation of endothelial cells from mesodermal precursors) and angiogenesis (i.e., blood vessel generation from pre-existing vessels), together with recent findings about angiogenesis and antiangiogenic therapies in hematopoietic malignancies such as leukemia, lymphoma, myeloma, and myelodysplastic syndromes.

Endostatin, an antiangiogenic drug, induces tumor stabilization after chemotherapy or anti-CD20 therapy in a NOD/SCID mouse model of human high-grade non-Hodgkin lymphoma

Both chemotherapy and chimeric anti-CD20 monoclonal antibodies are effective agents against B-cell non-Hodgkin lymphoma (NHL). However, patients achieving remission are at risk of relapse. To evaluate the effect of the antiangiogenic drug endostatin used alone and after the administration of cyclophosphamide (CTX) or the anti-CD20 antibody rituximab, we generated a new model of human NHL by transplanting Namalwa cells intraperitoneally into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. First, we determined the most effective treatment schedule for the drugs assessed. When administered alone, CTX (3 courses of 75 mg/kg of body weight given intraperitoneally), rituximab (3 courses of 25 mg/kg given intraperitoneally), and endostatin (5 courses of 50 microg given subcutaneously) delayed tumor growth, and CTX was the most effective in controlling bulky disease. When given after chemotherapy or immunotherapy, endostatin effectively induced tumor stabilization. When mice given CTX or rituximab on days 3, 5, and 7 after transplantation were randomly assigned to receive endostatin or phosphate-buffered saline on days 15 to 19, tumor growth was prevented in endostatin-treated mice as long as the drug was administered. Furthermore, administration of endostatin on days 25 to 29 after tumor regrowth still induced significant tumor regression, whereas CTX and rituximab were not effective. The specific antiangiogenic action of endostatin was confirmed by in vitro and in vivo studies indicating that the drug inhibited proliferation and induced apoptosis of endothelial (but not of NHL) cells. In conclusion, sequential administration of chemotherapy and endostatin seems promising for treating bulky NHL, and the less toxic sequential administration of rituximab and endostatin is promising for treating limited disease. (

Human myeloid and lymphoid malignancies in the non-obese diabetic/severe combined immunodeficiency mouse model: frequency of apoptotic cells in solid tumors and efficiency and speed of engraftment correlate with vascular endothelial growth factor production

Recent studies have suggested that non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice transplanted with human hematological malignancies show higher levels of engraftment compared with other strains. We used this model to compare xenotransplantability of human leukemia and lymphoma cell lines and to investigate angiogenesis in hematopoietic malignancies. Ten of 12 evaluated cell lines were able to engraft NOD/SCID mice within 120 days. A strong correlation was observed between the amount of vascular endothelial growth factor (VEGF) produced in vitro by cultured cells and the efficiency of tumor engraftment (r = 0.808; P = 0.001), and an inverse correlation was found between VEGF production and the time of tumor engraftment (r = -0.792; P = 0.006) and between VEGF production and the frequency of apoptotic/dead cells in solid tumors (r = -0.892; P = 0.007). Moreover, VEGF production correlated with the frequency of endothelial (CD31+/CD34+) cells in solid tumors (r = 0.897; P = 0.001). Taken together with in vitro data presented here and indicating that the VEGF antagonist Flt-1/Fc chimera inhibits leukemia and lymphoma cell proliferation, our findings support a role for tumor-derived VEGF in leukemia and lymphoma progression. Furthermore, the present study confirms previous observations indicating that VEGF expression may play a crucial role in xenotransplantability of human solid malignancies in SCID mice. The NOD/SCID model is promising for future evaluations of antiangiogenic drugs, alone or in combination with established chemo- or immunotherapy regimens.

Oligomerization of RAR and AML1 transcription factors as a novel mechanism of oncogenic activation

RAR and AML1 transcription factors are found in leukemias as fusion proteins with PML and ETO, respectively. Association of PML-RAR and AML1-ETO with the nuclear corepressor (N-CoR)/histone deacetylase (HDAC) complex is required to block hematopoietic differentiation. We show that PML-RAR and AML1-ETO exist in vivo within high molecular weight (HMW) nuclear complexes, reflecting their oligomeric state. Oligomerization requires PML or ETO coiled-coil regions and is responsible for abnormal recruitment of N-CoR, transcriptional repression, and impaired differentiation of primary hematopoietic precursors. Fusion of RAR to a heterologous oligomerization domain recapitulated the properties of PML-RAR, indicating that oligomerization per se is sufficient to achieve transforming potential. These results show that oligomerization of a transcription factor, imposing an altered interaction with transcriptional coregulators, represents a novel mechanism of oncogenic activation.

Antiviral activity of 2'-deoxy-3'-oxa-4'-thiocytidine (BCH-10652) against lamivudine-resistant human immunodeficiency virus type 1 in SCID-hu Thy/Liv mice

Oral administration of 2'-deoxy-3'-oxa-4'-thiocytidine (BCH-10652), a nucleoside analog structurally similar to lamivudine (3TC), caused dose-dependent inhibition of viral replication in SCID-hu Thy/Liv mice infected with human immunodeficiency virus type 1 NL4-3 and with an NL4-3 clone containing the M184V mutation in reverse transcriptase that confers resistance to 3TC. These experiments demonstrate the utility of this mouse model for evaluating drug resistance and for performing direct comparisons between antiviral compounds in vivo.

Isospin tracing: A probe of nonequilibrium in central heavy-Ion collisions

Four different combinations of 9644Ru and 9640Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400A MeV using a 4pi detector. The degree of isospin mixing between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the tritium to 3He yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions. Quantitative measures of stopping and mixing are extracted from the data. They are found to exhibit a quite strong sensitivity to the in-medium ( n,n) cross section used in microscopic transport calculations.

Cascade filtration for TTP: an effective alternative to plasma exchange with cryodepleted plasma

TTP remains enigmatic both in terms of etiology and management. The most recent approach is aggressive plasma exchange (PE) employing cryopoor plasma for replacement, based on the pathogenetic relevance given to exceedingly large Von Willebrand (VWF) multimers in the determination of the syndrome with normalization during remission. PE with fresh frozen plasma (FFP) is better than FFP infusion as shown by a recent Canadian study, supporting the theory that to treat TTP an offending circulating agent needs to be removed from the patient's plasma in contrast to the hypothesis that a missing factor is to be given along with FFP. A more recent hypothesis is supported by the results of studies published by the end of 1998 [Moake J, Chintagumpala M, Turner N et al. Blood 1994;84:490-97; Moake J, McPherson PD. Am J Med 1989;87: 3-9N] which would show that TTP is mediated by auto-antibodies to VWF-cleaving protease, or is the result of deficiency of the protease ascribed to abnormalities in its production, function or survival. Plasmapheresis without plasma infusion is relatively ineffective perhaps because it does not increase the protease activity. Cascade filtration (CF) is the autologous counterpart of plasmapheresis. It has been used by our group since 1980 to remove from patients plasma macromolecules such as VWF, fibrinogen, LDL and circulatory immune complexes (CIC). After secondary filtration, the autologous plasma has a composition which is very similar to that of allogeneic plasma after cryoprecipitation, a product which used in the management of TTP. Based on this knowledge, in 1994 we began to use CF in the treatment of TTP patients. In the beginning (7 patients) CF was combined with a decreasing number of conventional PEs using allogeneic plasma for substitution. Lately only CF with some plasma supplementation has been used in the last 9 cases. From a clinical point of view our 16 patients achieved remission after a number of treatments (11 +/- 7) that compares sufficiently well with those required by our historical control group of 47 cases (14 +/- 13). Of course the patient's exposure to allogenic plasma was significantly lower for patients in the CF only group (1.4 +/- 1.2 plasma U/session) compared to the PE + CF group (4.4 +/- 2.3 plasma U/session) or for the controls treated by PE only (10.8 +/- 4.6 plasma U/session). There were no deaths in the CF or PE + CF groups and no untoward effect was observed. On the contrary there were 5 deaths (1 on the day of presentation) in the PE group, and 1 HBV and 2 HCV infections as well as 4 severe allergic reactions to plasma proteins (or passive antibody infusion). We conclude that CF is presently the best treatment to offer to patients suffering from sporadic TTP and that CF may contribute to expanding the knowledge of the pathogenetic mechanisms of this uncommon multisystem disorder.

Human herpesvirus 6 (HHV-6) causes severe thymocyte depletion in SCID-hu Thy/Liv mice

Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that may act as a cofactor in the progression of AIDS. Here, we describe the first small animal model of HHV-6 infection. HHV-6 subgroup A, strain GS, efficiently infected the human thymic tissue implanted in SCID-hu Thy/Liv mice, leading to the destruction of the graft. Viral DNA was detected in Thy/Liv implants by quantitative polymerase chain reaction (PCR) as early as 4 d after inoculation and peaked at day 14. The productive nature of the infection was confirmed by electron microscopy and immunohistochemical staining. Atypical thymocytes with prominent nuclear inclusions were detected by histopathology. HHV-6 replication was associated with severe, progressive thymocyte depletion involving all major cellular subsets. However, intrathymic T progenitor cells (ITTPs) appeared to be more severely depleted than the other subpopulations, and a preferred tropism of HHV-6 for ITTPs was demonstrated by quantitative PCR on purified thymocyte subsets. These findings suggest that thymocyte depletion by HHV-6 may be due to infection and destruction of these immature T cell precursors. Similar results were obtained with strain PL-1, a primary isolate belonging to subgroup B. The severity of the lesions observed in this animal model underscores the possibility that HHV-6 may indeed be immunosuppressive in humans.

Genetic optimization of combinatorial libraries

Most agrochemical and pharmaceutical companies have set up high-throughput screening programs which require large numbers of compounds to screen. Combinatorial libraries provide an attractive way to deliver these compounds. A single combinatorial library with four variable positions can yield more than 10(12) potential compounds, if one assumes that about 1000 reagents are available for each position. This is far more than any high-throughput screening facility can afford to screen. We have proposed a method for iterative compound selection from large databases, which identifies the most active compounds by examining only a small fraction of the database. In this article, we describe the extension of this method to the problem of selecting compounds from large combinatorial libraries. Copyright 1998 John Wiley & Sons, Inc.

Analysis of the 16S rRNA gene sequence of the coryneform bacterium associated with hyperkeratotic dermatitis of athymic nude mice and development of a PCR-based detection assay

By 16S rDNA sequencing the authors have characterized the coryneform bacteria associated with hyperkeratotic dermatitis (HD) of athymic nude mice isolated from six different outbreaks of the disease in Northern Italy. This analysis has allowed the authors to confirm the classification of the bacteria as Corynebacterium bovis and to develop a 16S rDNA-based polymerase chain reaction (PCR) detection assay. The test was performed directly on the DNA extracted from epidermal swabs. The PCR primers were chosen to match the 16S rDNA sequence fragments which differ most from the other Corynebacterium spp. The test was shown to be both sensitive and specific for C. bovis. Detection of as few as three viable bacterial cells was possible with the use of an oligonucleotide probe in a liquid hybridization assay.

Hyperkeratosis-associated coryneform infection in severe combined immunodeficient mice

Hyperkeratosis-associated coryneform (HAC) is a coryneform bacterium, with a biochemical profile similar to Corynebacterium bovis, that causes hyperkeratotic dermatitis in athymic nude mice. In the present study 28 severe combined immunodeficient (SCID) mice coming from six different animal facilities were submitted for bacteriological and pathological examination. HAC was isolated from 10 SCID mice belonging to two of these facilities. Two of the HAC-infected mice showed macroscopical lesions consisting in large alopecic areas, with small white flakes, involving the dorsum, flanks, neck and cheeks. Histologically, the skin of these animals was characterized by diffuse acanthosis and hyperkeratosis. In the other eight HAC-infected SCID mice no macroscopical lesions were observed but focal areas of minimal to mild acanthosis were histologically detected in five cases. These results suggest that HAC can infect SCID mice inducing skin lesions similar, although generally less severe, to those observed in nude mice with hyperkeratotic dermatitis. Our results pointed out that SCID mice may play an important role in the epidemiology of hyperkeratotic dermatitis of athymic nude mice.

A human acute lymphoblastic leukemia line with the T(4;11) translocation as a model of minimal residual disease in SCID mice

This study describes a new human acute lymphoblastic leukemia (ALL) cell line (ALL-PO) with the t(4;11) translocation established in SCID mice. The ALL-PO line can be maintained by serial transplant in SCID mice with stable immunophenotypic, molecular and karyotypic features. After intravenous (i.v.) injection ALL-PO spread systemically involving the hematopoietic organs and the central nervous system (CNS) of all mice. The homing and the progression of the disease are evaluated by histological analysis and reverse-transcriptase polymerase chain reaction (RT-PCR) amplification of the t(4;11) translocation in the bone marrow, spleen and CNS of SCID mice at different times after engraftment. Occult leukemia was detectable by PCR in the bone marrow of SCID mice as early as three days after the i.v. injection of leukemic cells whereas the first signs of involvement of the spleen and CNS appeared after 14 days; after 24 days all the mice were euthanized because they were moribund and the bone marrow, spleen and CNS showed ample infiltration by leukemic cells. The sensitivity to conventional chemotherapy was tested in this model. ALL-PO in SCID mice did not respond to treatment with vincristine or idarubicin but cyclophosphamide (150 mg kg(-1) i.v., single injection) significantly increased the survival of the mice. The efficacy of such a treatment was more evident when cyclophosphamide was given in the early stages of the disease (detectable only by molecular analysis) but much less effective when the drug was administered when the disease could be detected by conventional histological analysis. The biological behavior and molecular characteristics of ALL-PO make it a good model for studying novel therapeutic strategies for a better control of minimal residual disease.

Outbreaks of hyperkeratotic dermatitis of athymic nude mice in northern Italy

Hyperkeratotic dermatitis of athymic nude mice is an infectious disease caused by a coryneform bacterium. During the spring of 1995, outbreaks of hyperkeratotic dermatitis were observed in several nude mice facilities in northern Italy. In this report we describe the clinical, histopathological and microbiological features of the disease in two different animal facilities. Affected animals showed a typical 'scaly' appearance with small white flakes of material adherent to the skin. In one of the outbreaks (facility 2) the lesions were less severe and involved only limited areas of the body. The infection spread very quickly and the morbidity reached more than 80% in a few days, while the mortality was about 1%. The lesions resolved spontaneously within 7-10 days. Histological examination of affected skin revealed orthokeratotic hyperkeratosis, acanthosis and dermal inflammatory infiltration which were more severe in mice from facility 1. In Gram-stained sections groups of rods consistent with coryneform bacteria were detectable in the keratin layers covering the epidermal surface. A coryneform bacterium, biochemically typed as Corynebacterium bovis, was isolated from 11 out of 11 mice from facility 1 and from 8 out of 11 mice from facility 2.

Establishment of human acute myelogenous leukemia lines secreting interleukin-1 beta in SCID mice

A reproducible in vivo model of human acute myelogenous leukemia (AML) was established in severe combined immunodeficient (SCID) mice. The AML-CL and AML-PS lines were originated from leukemic blasts purified respectively from the peripheral blood of a 27-year-old woman with previously untreated hyperleukocytotic AML and from the bone marrow of a 61-year-old man during the third leukemic relapse. The 2 lines were maintained and serially transplanted i.p. in SCID mice. AML-PS and AML-CL produced ascitogenous gross tumors after approximately 4 and 6 weeks, respectively, and all mice died within 6-8 weeks. Microscopic evaluation of different organs at autopsy showed massive involvement of bone marrow, liver and spleen, though with differences in the tumor burdens for the 2 lines (AML-CL > AML-PS). Flow cytometric analysis documented the spread of leukemic cells to bone marrow, peripheral blood and spleen. AML-PS and AML-CL cells show an immunophenotypic profile (CD13+, CD33+) and cytogenetic findings similar to freshly isolated blasts. Interleukin-1 beta (IL-1 beta) gene expression was observed by Northern blot analysis in leukemic cells from AML-CL and AML-PS SCID mice. After 24 hr of culture both lines released IL-1 beta in culture supernatants. High levels of circulating IL-1 beta were secreted in plasma of tumor-bearing mice. This AML-SCID murine model could contribute to an understanding of the mechanisms of AML growth in vivo and the possible role of the autocrine production of IL-1 beta in promoting cell growth.

[Sciatic and femoral nerve block with electro-neural stimulator (ENS) in surgery of the knee in day-care surgery]

This study was designed to evaluate locoregional anesthesia (double block of sciatic and femoral nerves with ENS) for ambulatory knee arthroscopic surgery. A statistical evaluation was performed in 50 adult outpatients (41 males, 9 females, ASA class 1 or 2) undergoing ambulatory knee arthroscopic procedures. Basal and intraoperative BP, HR SaO2 were recorded and the intensity of analgesia was also assessed according to the patient's subjective evaluation. Extra sedative or analgesic requirements were also recorded. There were no statistical changes in hemodynamic parameters during the perioperative period. The effectiveness of the anaesthetic block was classified as very good in 84% of patients, good in 2%, sufficient in 6% and inadequate in 8%. All patients were discharged in four hours after surgery. Our study shows that in ambulatory arthroscopic surgery, sciatic and femoral block with ENS is a valuable alternative to general anaesthesia.

[Earthenware and lead poisoning. Description of a case]

A case of acute lead poisoning caused by drinking wine that had been kept in a decorative amphora is reported. Chomico-physical analysis of the internal surface of the recipient evidenced a layer of lead paint very soluble in wine. It is hoped that this report will draw the attention of the practising physician and Preventive Medicine Departments to this unusual cause of saturnism. The craft production of earthenware recipients that have been inadequately glazed and their improper use as containers of drings of foods could be commoner than might be thought on the basis of the sporadic reporting of such cases of lead poisoning.