Quantifying the effectiveness of ultraviolet-C light at inactivating airborne Mycobacterium abscessus.

BACKGROUND: Mycobacterium abscessus (MABS) group are environmental organisms that can cause infection in people with cystic fibrosis (CF) and other suppurative lung diseases. There is potential for person-to-person airborne transmission of MABS among people with CF attending the same care centre. Ultraviolet light (band C, UV-C) is used for Mycobacterium tuberculosis control indoors; however, no studies have assessed UV-C for airborne MABS. AIM: To determine whether a range of UV-C doses increased the inactivation of airborne MABS, compared with no-UVC conditions. METHODS: MABS was generated by a vibrating mesh nebulizer located within a 400 L rotating drum sampler, and then exposed to an array of 265 nm UV-C light-emitting diodes (LED). A six-stage Andersen Cascade Impactor was used to collect aerosols. Standard microbiological protocols were used for enumerating MABS, and these quantified the effectiveness of UV-C doses (in triplicate). UV-C effectiveness was estimated using the difference between inactivation with and without UV-C. FINDINGS: Sixteen tests were performed, with UV-C doses ranging from 276 to 1104 µW s/cm2. Mean (±SD) UV-C effectiveness ranged from 47.1% (±13.4) to 83.6% (±3.3). UV-C led to significantly greater inactivation of MABS (all P-values ≤0.045) than natural decay at all doses assessed. Using an indoor model of the hospital environment, it was estimated that UV-C doses in the range studied here could be safely delivered in clinical settings where patients and staff are present. CONCLUSION: This study provides empirical in-vitro evidence that nebulized MABS are susceptible to UV-C inactivation.

Dynamin 2 mediates PDGFRα-SHP-2-promoted glioblastoma growth and invasion.

Dynamin 2 (Dyn2), a large GTPase, is involved in receptor tyrosine kinase (RTK)-promoted cell migration. However, the molecular mechanisms by which Dyn2 regulates RTK-induced cell migration have not been established. Recently, we reported that tyrosine-protein phosphatase non-receptor type 11 (SHP-2) and phosphatidylinositol 3-kinase (PI3K) mediate platelet-derived growth factor receptor-α (PDGFRα)-promoted glioma tumor growth and invasion. Here, we show that Dyn2 is an effector downstream of the PDGFRα-PI3K/SHP-2 signaling in glioma cells. Depletion of endogenous Dyn2 by short hairpin RNAs (shRNAs) inhibited PDGFRα-stimulated phosphorylation of Akt, Erk1/2, Rac1 and Cdc42 activities, glioma cell migration and survival in vitro and tumor growth and invasion in the brains of mice. Dyn2 binds to SHP-2 and PI3K and colocalizes with PDGFRα at the invasive fronts in PDGF-A-stimulated glioma cells. Inhibition of SHP-2 by siRNA knockdown abrogated Dyn2 association with activated PDGFRα and PDGFRα activation of Rac1 and Cdc42, and glioma cell migration, thereby establishing a link between SHP-2 interaction with Dyn2 and the PDGFRα signaling. Furthermore, a dominant-negative SHP-2 C459S mutant inhibited PDGF-A-stimulated glioma cell migration, phosphorylation of Dyn2 and concomitantly blocked PDGFRα-induced Src activation. Inhibition of Src by Src inhibitors attenuated PDGF-A-stimulated phosphorylation of Akt and Dyn2 and glioma cell migration. Additionally, mutations of binding sites to PI3K, SHP-2 or Src of PDGFRα impaired PDGFRα-stimulated phosphorylation of Akt and Dyn2, and Dyn2 association with activated PDGFRα. Taken together, this study identifies Dyn2 as an effector that mediates PDGFRα-SHP-2-induced glioma tumor growth and invasion, suggesting that targeting the PDGFRα-SHP-2-Dyn2 pathway may be beneficial to patients with malignant glioblastomas.

Absence of truncating BRIP1 mutations in chromosome 17q-linked hereditary prostate cancer families.

BACKGROUND: In a genome-wide scan (GWS) of 175 multiplex prostate cancer (PCa) families from the University of Michigan Prostate Cancer Genetics Project (PCGP), linkage was observed to markers on chromosome 17q21-24, a region that includes two breast cancer susceptibility genes, BRCA1 and BRIP1. BRIP1 is a Fanconi anaemia gene (FANCJ) that interacts with the BRCT domain of BRCA1 and has a role in DNA damage repair. Protein truncating mutations in BRIP1 have been identified in hereditary breast and ovarian cancer families, and a recent report suggested that a recurrent truncating mutation (R798X) may have a role in PCa susceptibility. METHODS: We examined the role of BRIP1 mutations in hereditary PCa through sequence analysis of 94 individuals from PCGP families showing linkage to 17q. RESULTS: A total of 24 single-nucleotide polymorphisms, including 7 missense variants but no protein truncating mutations, were observed. CONCLUSION: The data presented here suggest that BRIP1 truncating mutations are uncommon in PCa cases and do not account for the linkage to chromosome 17q observed in our GWS. Additional investigation is needed to determine the significance, if any, of the observed BRIP1 missense variants in hereditary PCa.

Glenohumeral motion: review of measurement techniques.

Measurement of upper limb motion is problematic, not least because of the large range of path dependent description of motion of the joints, and the multiple non-cyclical unstandardised motion tasks measured. Furthermore, appreciation of shoulder motion specifically is obscured by overlying soft tissue. In order to satisfy the complexity of a clinically useful model of the movement of the joint, input data must be acquired from a set of pre-determined movements using a non-invasive technique with a high level of accuracy. Descriptive and predictive modeling of the glenohumeral joint requires input of high-fidelity data into a 6 degree of freedom representation, without which, the application of the tool is of limited clinical significance to the advancement of both operative and non-operative management of shoulder pathology. Electromagnetic, linkage and radiographic techniques have previously been used, however, an optimal solution is yet to be described.

Correlation of virus replication in tissues with histologic lesions in Atlantic salmon experimentally infected with infectious salmon anemia virus.

We have studied the replication of virus in tissues and development of lesions associated with infectious salmon anemia virus (ISAV) infection in Atlantic salmon using in situ hybridization (ISH) with a riboprobe targeting ISAV RNA segment 7 messenger RNA. Fish were infected with three ISAV isolates (U5575-1, RPC-01-0593-1, Norway 810/9/99) and then euthanatized sequentially at 3, 6, 10, and 13 days postinoculation (dpi) and thereafter once a week for 8 weeks. Severe histopathologic lesions were observed in tissues from all groups beginning at the onset of mortality. The severe histopathologic lesions correlated with maximum intensity and frequency of ISH signals (P < 0.001). There was a strong association between the hybridization signals and severity of lesions in the liver, kidney, and heart (R = 0.81, 0.70, and 0.78, respectively; P < 0.001). The distribution of ISH signals indicated the presence of a viremia because signals were observed predominantly in individual blood cells and endothelial cells, and possibly hematopoietic cells of head kidney, but not in the necrotic hepatocytes and renal epithelium. Of the organs sampled, the heart was the first and last to show ISH signals, possibly because of increased activity of the endocardial endothelial cells and the underlining macrophages, which continuously trap and remove circulating virus, and therefore represents the best tissue sample for screening of suspected infected fish. On the basis of mortality, severity of lesions, and intensity and frequency of ISH signals, ISAV isolate Norway 810/9/99 was the most virulent and U5575-1 the least virulent isolate studied.

The tyrosine phosphatase SHP-2 is required for mediating phosphatidylinositol 3-kinase/Akt activation by growth factors.

SHP-2 is a ubiquitously expressed non-transmembrane tyrosine phosphatase with two SH2 domains. Multiple reverse-genetic studies have indicated that SHP-2 is a required component for organ and animal development. SHP-2 wild-type and homozygous mutant mouse fibroblast cells in which the N-terminal SH2 domain was target-deleted were used to examine the function of SHP-2 in regulating Phosphatidylinositol 3-Kinase (PI3K) activation by growth factors. In addition, SHP-2 and various mutants were introduced into human glioblastoma cells as well as SHP-2(-/-) mouse fibroblasts. We found that EGF stimulation and EGFR oncoprotein (DeltaEGFR) expression independently induced the co-immunoprecipitation of the p85 subunit of PI3K with SHP-2. Targeted deletion of the N-terminal SH2 domain of SHP-2 severely impaired PDGF- and IGF-induced Akt phosphorylation. Ectopic expression of SHP-2 in U87MG gliobastoma cells elevated EGF-induced Akt phosphorylation, and the effect was abolished by mutation of its N-terminal SH2 domain. Likewise, the reconstitution of SHP-2 expression in the SHP-2(-/-) cells enhanced Akt phosphorylation induced by EGF while rescuing that induced by PDGF and IGF. Further lipid kinase activity assays confirmed that SHP-2 modulation of Akt phosphorylation correlated with its regulation of PI3K activation. Based on these results, we conclude that SHP-2 is required for mediating PI3K/Akt activation, and the N-terminal SH2 domain is critically important for a "positive" role of SHP-2 in regulating PI3K pathway activation.

Abdominal aortic aneurysm in women.

OBJECTIVE: The purpose of this study was to compare abdominal aortic aneurysm (AAA) associations in men and women. METHODS: Veterans aged 50 to 79 years without a previous history of AAA underwent ultrasound screening for AAA after completing a questionnaire on demographic information and potential risk factors. RESULTS: A total of 122,272 men and 3450 women were successfully screened. An AAA of 3.0 cm or greater in diameter was found in 4.3% of men and 1.0% of women (P <.001). Contrary to a previous report, we did not find suprarenal aortic enlargement accompanying AAA to be more common in women. The principal associations that we have previously reported for AAA in this cohort (age, smoking, family history of AAA, and a negative association with diabetes) were all similar in women compared with men. In age- and smoking-adjusted models, the interaction terms indicated that black race and cancer were more strongly associated with AAA in women than men (P <.05). Height and cerebral vascular disease were also more strongly associated with AAA in women than in men, but these interaction terms did not reach statistical significance (P <.10). Although the other differences were unexpected and require confirmation, the trend toward a stronger association of cerebral vascular disease with AAA in women is consistent with two previous reports. CONCLUSIONS: Despite the much lower prevalence of AAA in women, the most important associations with AAA are similar to those seen in men. Our data provide some support for a previous finding that cerebrovascular disease may be more closely associated with AAA in women than in men.

The design of a five-degree-of-freedom powered orthosis for the upper limb.

In response to the need for a sophisticated powered upper-limb orthosis for use by people with disabilities and/or limb weakness or injury, the MULOS (motorized upper-limb orthotic system) has been developed. This is a five-degree-of-freedom electrically powered device having three degrees of freedom at the shoulder, one at the elbow and one to provide pronation/supination. The shoulder mechanism consists of a serial linkage having an equivalent centre of rotation close to that of the anatomical shoulder; this is a self-contained module in which power transmission is provided by tensioned cables. The elbow and pronation/supination modules are also self-contained. The system has been designed to operate under three modes of control: 1. As an assistive robot attached directly to the arm to provide controlled movements for people with severe disability. In this case, it can be operated by a variety of control interfaces, including a specially designed five-degree-of-freedom joystick. 2. Continuous passive motion for the therapy of joints after injury. The trajectory of the joints is selected by 'walk-through' programming and can be replayed for a given number of cycles at a chosen speed. 3. As an exercise device to provide strengthening exercises for elderly people or those recovering from injury or surgery. This mode has not been fully implemented at this stage. In assistive mode, prototype testing has demonstrated that the system can provide the movements required for a range of simple tasks and, in continuous passive motion (CPM) mode, the programming system has been successfully implemented. Great attention has been paid to all aspects of safety. Future work is required to identify problems of operation, and to develop new control interfaces.

Epidermal growth factor (EGF) receptor kinase-independent signaling by EGF.

The ErbB family of receptors, which includes the epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4, mediate signaling by EGF-like polypeptides. To better understand the role of the EGFR tyrosine kinase, we analyzed signaling by a kinase-inactive EGFR (K721M) in ErbB-devoid 32D cells. K721M alone exhibited no detectable signaling capacity, whereas coexpression of K721M with ErbB2, but not ErbB3 or ErbB4, resulted in EGF-dependent mitogen-activated protein kinase (MAPK) activation. The kinase activity, but not tyrosine phosphorylation, of ErbB2 was required for EGF-induced MAPK activation. The presence of tyrosine phosphorylation sites in K721M was not a requisite for signaling, indicating that transphosphorylation of K721M by ErbB2 was not an essential mechanism of receptor activation. Conversely, the mutated kinase domain of K721M (residues 648-973) and tyrosine phosphorylation of at least one of the receptors were necessary. EGF was found to activate the pro-survival protein kinase Akt in stable cell lines expressing K721M and ErbB2 but, unlike cells expressing wild-type EGFR, was incapable of activating signal transducers and activators of transcription (STAT) or driving cell proliferation. These results demonstrate that EGFR-ErbB2 oligomers are potent activators of MAPK and Akt, and this signaling does not require EGFR kinase activity.

The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators.

BACKGROUND: We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73451 veterans aged 50 to 79 years who underwent ultrasound screening. OBJECTIVE: To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings. METHODS: In the new cohort of veterans undergoing screening, 52 745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors. RESULTS: We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0. 18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126 196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker. CONCLUSIONS: Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.

Antisense expression for amphiregulin suppresses tumorigenicity of a transformed human breast epithelial cell line.

The epidermal growth factor (EFG) family of receptors and their respective ligands play a major role in breast cancer progression and are the targets of new therapeutic approaches. Following immortalization with SV40 T antigen of normal human breast epithelial cells, a transformed variant cell line (NS2T2A1) was selected for its increased tumorigenicity in nude mice. This cell line was shown to have a higher expression of EGF receptors (EGFR) and amphiregulin (AR) when compared to their normal counterparts or less aggressive transformed cells. Dual staining of EGFR and AR was observed in 50-60% of NS2T2A1 cells, while 30-40% cells expressed AR only. To explore the potential tumorigenic role of AR, a 1.1 kb AR cDNA in an antisense orientation was transfected in NS2T2A1 cells. Three clones, selected by hygromycin B, expressed AR antisense RNA (AR AS1, AR AS2 and AR AS3 cell lines) in which AR protein expression was reduced (ranging from about 50 to < 5%). The anchorage-independent growth of AR AS cell lines was reduced to levels ranging from 32.4-6.8% relative to the control cell line transfected with the vector alone. The clones expressing AR antisense RNA showed a reversion of the malignant phenotype when injected in nude mice, since a significant reduction of tumor intake was observed coincident with a significant tumor mass reduction (> 96%). Moreover, intra-tumoral vascularization decreased significantly in tumors derived from AR AS cells (26.7, 70.7 and 50.4% of control). These in vitro and in vivo data reveal the oncogenic nature of AR in transformed breast epithelial cells and imply a role for AR in tumor angiogenesis.

Higher prevalence of abdominal aortic aneurysms in patients with carotid stenosis but without diabetes.

BACKGROUND: We compared abdominal aortic aneurysm (AAA) prevalence in 3 groups of patients at the Hines Veterans Affairs Medical Center: (1) patients with 50% or more carotid stenosis, (2) patients with less than 50% stenosis, and (3) patients screened for the Aneurysm Detection and Management (ADAM) study. METHODS: Of all the patients referred to the vascular laboratory for carotid duplex examination during a 12-month period, patients with 50% or more carotid stenosis underwent ultrasonography of the abdominal aorta unless they had a previous scan or previous aortic surgery (group 1, n = 374). Patients with less than 50% carotid stenosis who had been screened for ADAM comprised group 2 (n = 139). They were compared with all patients screened for ADAM at our center during the same time period (group 3, n = 2477). RESULTS: AAA of 3.0 cm or more were present in 18.2%, 12.2%, and 7.2% of groups 1, 2, and 3, respectively; AAA of 4.0 cm or more were present in 8.3%, 5.8%, and 2.1% of groups 1, 2, and 3, respectively. Among patients with carotid stenosis, those patients without diabetes accounted for the observed increase in prevalence (21.9 % > or = 3.0 cm and 10.2% > or = 4.0 cm vs 9.2% and 2.8% in patients with diabetes). CONCLUSIONS: The relative risk of AAA is 2 to 3 times greater in patients with carotid stenosis compared with patients undergoing routine screening. However, only patients without diabetes account for the increased prevalence. Selective AAA screening of patients who are not diabetic with carotid stenosis is recommended.

A differential requirement for the COOH-terminal region of the epidermal growth factor (EGF) receptor in amphiregulin and EGF mitogenic signaling.

The epidermal growth factor receptor (EGFR) mediates the actions of a family of bioactive peptides that include epidermal growth factor (EGF) and amphiregulin (AR). Here we have studied AR and EGF mitogenic signaling in EGFR-devoid NR6 fibroblasts that ectopically express either wild type EGFR (WT) or a truncated EGFR that lacks the three major sites of autophosphorylation (c'1000). COOH-terminal truncation of the EGFR significantly impairs the ability of AR to (i) stimulate DNA synthesis, (ii) elicit Elk-1 transactivation, and (iii) generate sustained enzymatic activation of mitogen-activated protein kinase. EGFR truncation had no significant effect on AR binding to receptor but did result in defective GRB2 adaptor function. In contrast, EGFR truncation did not impair EGF mitogenic signaling, and in c'1000 cells EGF was able to stimulate the association of ErbB2 with GRB2 and SHC. Elk-1 transactivation was monitored when either ErbB2 or a truncated dominant-negative ErbB2 mutant (ErbB2-(1-813)) was overexpressed in cells. Overexpression of full-length ErbB2 resulted in a strong constitutive transactivation of Elk-1 in c'1000 but only slightly stimulated Elk-1 in WT or parental NR6 cells. Conversely, overexpression of ErbB2-(1-813) inhibited EGF-stimulated Elk-1 transactivation in c'1000 but not in WT cells. Thus, the cytoplasmic tail of the EGFR plays a critical role in AR mitogenic signaling but is dispensable for EGF, since EGF-activated truncated EGFRs can signal through ErbB2.

Expression of cripto and amphiregulin in colon mucosa from high risk colon cancer families.

We assessed the expression of the epidermal growth factor (EGF)-related peptides, cripto-I (CR-I) and amphiregulin (AR), in a small panel of human colon adenomas and carcinomas. CR-I immunoreactivity was found in 17/31 (55%) of colon adenomas, and in 33/39 (84%) colon carcinomas. AR immunostaining was observed in 16/26 adenomas (61%) and in 20/26 carcinomas (77%). CR-I and AR staining were also assessed in 29 specimens from 24 individuals that belong to families with high incidence of colorectal carcinoma, and in 5 non-high risk individuals. Expression of CR-I was detected in 18/29 (62%) of high risk colon mucosa specimens, but only in 1/5 (20%) specimens from non-high risk individuals, while AR staining was found in 20/29 (69%) and in 4/5 (80%) of colon mucosa samples from high and low risk individuals, respectively. A majority (21/29; 72%) of the specimens from the high risk individuals had a high proliferative rate, as measured by Ki-67 staining. A statistically significant correlation was found between high proliferative rate, increased expression of CR-I and reduced expression of AR in the mucosa specimens from high risk individuals, suggesting that these might represent early events in colon tumorigenesis.

Squamous cell hyperplastic foci: precursors of cutaneous papillomas induced in SENCAR mice by a two-stage carcinogenesis regimen.

We have conducted a series of experiments to characterize the lesions that are precursors of cutaneous papillomas in SENCAR mice initiated with 7,12-dimethylbenz(a)anthracene (DMBA) and promoted with 12-O-tetradecanoylphorbol-13-acetate (TPA). The first grossly detectable lesions at sites where papillomas subsequently developed were papules, slightly raised areas of skin ranging in diameter from 0.25 to approximately 1.5 mm. Papules were first detected in DMBA-initiated mice 21 days after the start of dosing with TPA. Of 78 DMBA/TPA-induced papules tracked during 15 weeks of TPA treatments, 68% progressed to papillomas, 9% persisted as papules, and 22% completely regressed. Histological evaluation of serial sections of 69 DMBA/TPA-induced papules revealed that they were focal hyperplastic lesions that we refer to as squamous cell hyperplastic foci (SCHF). These hyperproliferative lesions appeared to progress through two distinct stages. Stage I SCHF were characterized as regular hyperplastic foci involving the interfollicular epidermis and the outer root sheaths of 1 or more hair follicles down to the level of the sebaceous glands. Stage II SCHF were foci of irregular epithelial hyperplasia with increased fibrovascular stroma and involved from 3 to >10 hair follicles. Prominent dilated capillaries and inflammatory cell infiltrates were frequently associated with both stage I and II SCHF. Ha-ras gene codon 61 mutations were detected in 7 of 10 stage I SCHF and 13 of 14 stage II SCHF microdissected from histological sections and 7 of 7 of whole papules by mutation-specific PCR analysis. These data provide molecular evidence that SCHF are foci of initiated cells. Further study of these lesions may contribute to more fully defining the sequence of molecular and cellular changes necessary for tumorigenesis in mouse skin. SCHF may also have utility as early indicators of potential skin tumorigenicity in cancer bioassays.

A common requirement for the catalytic activity and both SH2 domains of SHP-2 in mitogen-activated protein (MAP) kinase activation by the ErbB family of receptors. A specific role for SHP-2 in map, but not c-Jun amino-terminal kinase activation.

The ErbB family of receptors, which include the epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4 mediate the actions of a family of bioactive polypeptides. EGF signals through EGFR, whereas heregulin (HRG) signaling is initiated through binding to either ErbB3 or ErbB4. In this report we studied the role of protein-tyrosine phosphatase SHP-2 in ErbB-mediated activation of mitogen-activated protein kinase (MAPK) by overexpressing SHP-2 mutants in COS-7 cells. We demonstrate that enzymatic activity and both NH2- and COOH-terminal SH2 domains of SHP-2 are required for EGF-induced MAPK activation, but not for c-Jun amino-terminal kinase stimulation or MAPK activation which occurred in response to myristoylated son of sevenless, activated Ras, or phorbol ester. Dominant-negative forms of SHP-2 had no effect on EGF-stimulated interaction of GRB2 with EGFR or SHC, nor did they influence phosphorylation of SHC and SHC/EGFR association. The same mutant SHP-2 structures that inhibited EGF-mediated stimulation of MAPK also blocked HRG alpha/beta-induced MAPK activation. EGF or HRG beta caused SHP-2 SH2 domains to engage multiple phosphotyrosine proteins, and mutation of either domain disrupted these associations. These results demonstrate that SHP-2 performs a common and essential function(s) in ligand-stimulated MAPK activation by the ErbB family of receptors.

A study of the dimensions and taper angles of the medullary canals of the proximal and middle phalanges.

The morphology and dimensions of the medullary canals of the proximal and middle phalanges have been studied with particular interest shown to the angle of taper of these canals. Measurements of 50 cadaveric fingers were taken from computer aided tomographic images using AutoCAD software. Tangents were fitted to the inner cortices in two orthogonal planes and the angles between them were measured. The angles of canal taper in the proximal phalanx were remarkably similar for each digit. This was also true for the middle phalanx of the index, middle and ring fingers but the taper of the middle phalanx of the little finger was found to be different.

Expression of the Wilms' tumor suppressor gene, WT1, is upregulated by leukemia inhibitory factor and induces monocytic differentiation in M1 leukemic cells.

The Wilms' tumor gene, WT1, encodes a transcription factor of the Cys2-His2 zinc finger type. The functional significance of WT1 expression in leukemias, in addition to tissues and cell lines of hematopoietic origin, has not been determined. Using the murine myeloblastic leukemia cell line M1 as a model for macrophage differentiation, expression of WT1 is shown to be activated in M1 cells 24 hours after differentiation induction by leukemia inhibitory factor (LIF). Upregulation of WT1 in these cells is associated with cellular differentiation, coinciding with expression of the monocyte/macrophage marker c-fms, and the appearance of mature cells. WT1 isoforms lacking the KTS insert are unable to be ectopically expressed in M1 cells. Stable expression of the WT1 isoforms containing the KTS insert leads to spontaneous differentiation of the M1 myeloblasts through the monocytic differentiation pathway. These cells express c-fms, in addition to the myeloid-specific cell surface marker Mac-1. Exposure of these cells to LIF results in the rapid onset of terminal macrophage differentiation, accompanied by apoptotic cell death. These results show that the WT1 gene is an important regulator of M1 cell monocytic differentiation in vitro, and suggests a potential role for this gene in the molecular control of hematopoiesis.

Relationship of age, gender, race, and body size to infrarenal aortic diameter. The Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Investigators.

PURPOSE: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors. METHODS: Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a pre-screening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD > or = 3.0 cm). RESULTS: Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m2 in body mass index, and 0.35 m2 in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size. CONCLUSIONS: Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD > or = 3.0 cm) to be warranted.

Evidence that initiated keratinocytes clonally expand into multiple existing hair follicles during papilloma histogenesis in SENCAR mouse skin.

We have previously shown that the precursors of cutaneous papillomas in SENCAR mice initiated with 7,12-dimethylbenz[a]anthracene and promoted with 12-O-tetradecanoylphorbol-13-acetate are focal hyperplastic lesions that we refer to as squamous cell hyperplastic foci (SCHF). Ha-ras gene codon 61 mutations were frequently found in SCHF, providing evidence that these lesions represent clones of initiated cells. We report here the pathogenesis of multiple hair follicle involvement in more advanced SCHF and describe the role of the hair follicle in papilloma histogenesis. Detailed histological evaluation of 83 SCHF and 25 early papillomas revealed a morphological continuum from the least developed SCHF, involving only one hair follicle, to advanced SCHF and early papillomas, which involved more than 10 hair follicles. These results provide evidence of the recruitment of additional hair follicles as SCHF progress. In advanced SCHF and early papillomas the bulk of the epithelial component in all cases consisted of several markedly hyperplastic adjacent hair follicles, whereas the involved interfollicular epidermis (IFE) was generally less hyperplastic. All of the hair follicles involved in SCHF appeared to have been preexisting, based on their pattern of spacing, that they were consistently normal appearing below the level of the sebaceous glands, and that they were in the same phase of the hair cycle as surrounding, uninvolved hair follicles. Also, no evidence of follicular neogenesis was observed in serially sectioned SCHF, and coalescence of smaller lesions was rare. To investigate whether the involvement of multiple hair follicles in SCHF was due to expansion of initiated cells into existing hair follicles or, possibly, to a paracrine mechanism, we analyzed different levels of three serially sectioned SCHF and one early papilloma for Ha-ras mutations. These analyses revealed cells with Ha-ras gene codon 61 mutations at multiple levels that involved different hair follicles. Overall, our results provide evidence that as initiated cells clonally expand, they spread across the IFE and populate the upper permanent portions of existing hair follicles. The abnormal proliferation of the infundibula of the hair follicles involved in SCHF appears to give rise to most of the epithelial component of papillomas.