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B J Davis

Publications and source records attributed to B J Davis.

At least 19 recordsLinked to original sources
PubMed2001

Mono-(2-ethylhexyl) phthalate suppresses aromatase transcript levels and estradiol production in cultured rat granulosa cells.

The female reproductive toxicity of di-(2-ethylhexyl) phthalate and its active metabolite mono-(2-ethylhexyl) phthalate (MEHP) is attributed to suppression of ovarian granulosa cell estradiol production. In these studies, several structurally related phthalates (0-200 microM) and Wy-14,643 (0-100 microM) were compared to MEHP for their effects on granulosa cell estradiol production and transcript levels of cytochrome P450 enzyme CYP 19, also known as aromatase (P450arom), the rate-limiting enzyme in the conversion of androgens to estrogens. Granulosa cells were obtained from 28-day-old Fisher 344 rats and were cultured for 48 h. Test chemical or DMSO was added at the time of culture, along with testosterone as a substrate for aromatase. 17beta-Estradiol production was measured by standard radioimmunoassay, mRNA was measured by fluorescent RT-PCR, and protein was measured by Western blot analysis. MEHP was unique among the phthalates in its ability to decrease estradiol production, while Wy-14,643 had effects similar to MEHP at 100 microM. MEHP and Wy-14,643 also significantly decreased aromatase mRNA levels. The decrease in mRNA was concentration dependent and was paralleled by a decrease in aromatase protein. MEHP did not alter levels of CYP 11A1, the cholesterol side-chain cleavage enzyme (P450scc). Treatment with a cAMP analogue increased expression of P450scc in the presence of MEHP (100 to 200 microM) while the decrease in aromatase remained. Thus, these studies suggest that MEHP is distinct from several structurally related phthalates but similar to the peroxisome proliferator Wy-14,643 in its action on granulosa cell estradiol production. Moreover, the suppression of estradiol by MEHP is likely mediated through its action on aromatase transcript levels independent of cAMP-stimulated regulation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2001

Concurrent pernicious anemia and myelodysplastic syndrome.

Megaloblastic anemia (MA) due to vitamin B12 deficiency is a reversible form of ineffective hematopoiesis. Myelodysplastic syndrome (MDS) is an acquired, irreversible disorder of ineffective hematopoiesis, characterized by stem cell dysfunction as a consequence of DNA damage manifested in part by karyotype anomalies. Importantly, MA and MDS are generally considered mutually exclusive diagnoses. We report the case of a 73-year-old woman with a profound macrocytic anemia, monocytosis and neurologic symptoms. Low cobalamin levels and the presence of anti-intrinsic-factor antibodies definitively established a diagnosis of pernicious anemia. Replacement therapy resulted in resolution of neurologic findings and macrocytosis; however, the anemia and monocytosis persisted. Bone marrow biopsy revealed trilineage myelodysplasia, which together with the peripheral monocytosis suggested a diagnosis of chronic myelomonocytic leukemia. Karyotype analysis revealed a clone with 45, XX, +der(1;7)(q10;p10)-7 [20]. Eighteen months after documented vitamin B12 replenishment her MDS transformed to terminal acute myeloid leukemia with the same clonal abnormality. Reversible cytogenetic abnormalities have been observed with MA, occasionally including karyotypes typically associated with MDS or myeloid leukemias. These abnormalities, like the anemia, resolve with vitamin replacement. This case suggests that MA and MDS can occur simultaneously; clinicians should be aware that this phenomenon occurs. Whether acquired karyotype abnormalities from the MA were related to the MDS and subsequent myeloid leukemia in this woman is a speculative but intriguing consideration that is discussed.

Aged↗
PubMed2001

Rosai-Dorfman disease isolated to the central nervous system: a report of 11 cases.

Sinus histocytosis with massive lymphadenopathy, also known as Rosai-Dorfman Disease (RDD), is an idiopathic histiocytic proliferation affecting lymph nodes. Although extranodal involvement has been reported in diverse sites, central nervous system (CNS) manifestation, particularly in the absence of nodal disease is uncommon. We report 11 cases of RDD primary to the CNS without evidence of other sites of involvement. The cases included 7 males and 4 females ranging in age from 22 to 63 years (mean: 41 y). The patients presented with headaches, seizures, numbness, or paraplegia. Eight cases involved the cranial cavity and three cases, the spinal canal. Lesions were most often extra-axial and dura based. Only one presented in the CNS parenchyma. Histologically, the lesions consisted of variable numbers of pale-staining histocytes with emperipolesis often overshadowed by extensive lymphoplasmacytic infiltrates and fibrosis in the background. Special stains for organisms were negative. By immunohistochemical analysis, the characteristic histiocytes were positive for S100 protein and CD68 and negative for CD1a. Treatment consisted of surgical biopsy or excision. Follow-up, available for 10 cases with intervals ranging from 5 days to 42 months (mean: 15 mo), disclosed one patient dying of operative complications 5 days after biopsy and nine patients with no evidence of disease progression RDD should be considered in the differential diagnosis of inflammatory lesions of the CNS. Our study suggests that this entity may have been misdiagnosed in the past as plasma cell granuloma or inflammatory pseudotumor.

Adult↗
PubMed2001

Leukemia cutis in a patient with chronic neutrophilic leukemia.

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative disorder. Less than 50 cases have been reported. We report the first case of CNL with an associated leukemia cutis. CNL was diagnosed in a 74-year-old white woman in 1998, based on neutrophilic infiltration of the bone marrow and absence of the Philadelphia chromosome. The patient presented to the dermatology service in August 1998 with a 2-week history of a pruritic eruption on the arms, hands, and legs. Physical examination revealed red to violaceous plaques on both thighs and knees, in addition to purpuric patches and plaques on the dorsal hands, arms, and legs. Leukemia cutis was demonstrated on biopsy specimens of several lesional sites. The eruption progressed, despite treatment with topical and systemic corticosteroids. Treatment with systemic chemotherapy did affect partial resolution of the eruption, with parallel decreases in bone pain and white blood cell count, but the disease progressed and the patient ultimately died 5 months after her initial skin findings. Only one other case of CNL with dermatologic manifestations has been reported, CNL associated with a reactional neutrophilic dermatosis. Comparison to and differentiation from this case is discussed. The importance of distinguishing the specific infiltrates of leukemia from the nonspecific infiltrates of reactional dermatoses, such as Sweet's syndrome, is illustrated.

Aged↗
PubMed2001

Olfactory marker protein immunohistochemistry and the anterograde transport of horseradish peroxidase as indices of damage to the olfactory epithelium.

The present study compared the relative effectiveness of wheatgerm agglutinin--horseradish peroxidase (WGA--HRP) and olfactory marker protein (OMP) in detecting the presence of intact olfactory axons in glomeruli of the main olfactory bulb (MOB) in the rat. The olfactory epithelium was damaged by i.p. injections of the toxin 3-methyl indole and, after 5 or 6 days, the olfactory sac was injected with a 1% WGA--HRP solution. No anterograde labeling was observed in the dorsal and ventromedial quadrants of the MOB in the WGA--HRP material. However, in the same cases OMP immunostaining was observed throughout the MOB. In other rats the rostral olfactory epithelium was aspirated unilaterally and after 3, 11 and 16 days the olfactory sacs were injected with WGA--HRP and rats were perfused 1 day later. In these cases WGA--HRP reaction product was absent in the dorsolateral quadrant of the MOB on the aspirated side in all animals, but OMP immunostaining could be detected in the 4 and 12 day survival animals but not in the 17 day survival rat. These findings indicate that anterograde transport of WGA--HRP accurately reflects the presence of intact axons en route to the MOB. In contrast, OMP immunostaining persists in axon terminals severed from their parent cell body for at least 12 days and is a less useful marker of intact olfactory axons in experiments using short survival times.

Animals↗
PubMed2001

Mercury vapor and female reproductive toxicity.

Epidemiological studies finding menstrual cycle abnormalities among women occupationally exposed to Hg degrees prompted us to investigate the mechanisms of reproductive toxicity of Hg degrees in the female rat. Nose-only Hg degrees vapor inhalation exposures were conducted on regularly cycling rats 80-90 days of age in dose-response and acute time-course studies, which have previously proven useful as a model to identify ovarian toxicants. Vaginal smears were evaluated daily and serum hormone levels were correlated with cycle and with ovarian morphology at necropsy. Exposure concentration-related effects of Hg degrees were evaluated by exposing rats to 0, 1, 2, or 4 mg/m3 Hg degrees vapor 2 h/day for 11 consecutive days. Tissue Hg levels correlated with exposure concentration and duration. Exposure of rats to 4 mg/m3 (but not 1 or 2 mg/m3) Hg vapor for 11 days resulted in significant decreases in body weights relative to controls. Estrous cycles were slightly prolonged in the 2 and 4 mg/m3 dose groups, and serum estradiol and progesterone levels were significantly different in the 4 mg/m3 group compared to controls. The alterations in cycle and hormones at the 4 mg/m3 exposure concentration were attributed to body weight loss and generalized toxicity. In the time-course study, rats were exposed to 2 mg/m3 Hg degrees or air beginning in metestrus and evaluated daily for 8 days. A lengthening of the cycle was detected and morphological changes were observed in the corpora lutea (CL) after exposure for 6 days. To determine if changes in the CL and cyclicity correlated with a functional defect, rats were exposed to Hg degrees vapor and evaluated for pregnancy outcome. There were no significant effects on pregnancy rate or numbers of implantation sites when rats were exposed to 1 or 2 mg/m3 Hg degrees for 8 days prior to breeding, or when exposed for 8 days after breeding. These studies indicate that exposure to Hg degrees vapor altered estrous cyclicity, but had no significant effect on ovulation, implantation, or maintenance of first pregnancy during exposure of short duration in female rats.

Administration, Inhalation↗
PubMed2001

The effects of perinatal/juvenile heptachlor exposure on adult immune and reproductive system function in rats.

This study was performed to determine if developmental exposure of rats to heptachlor (H) during the last half of gestation through puberty adversely affects adult functioning of the immune and reproductive systems. Time-bred pregnant female Sprague-Dawley rats were dosed by gavage with H (0, 30, 300, or 3000 microg/kg/day) from gestation day (GD) 12 to postnatal day (PND) 7, followed by direct dosing of the pups with H through PND 42. Separate groups of rats were evaluated with a battery of immune function tests, while other groups of rats were evaluated for reproductive development and function. Additional groups of rats were euthanized at the end of the dosing period for histological analyses of major organ systems. Some dams and PND 7 pups were euthanized; milk, plasma, fat and/or tissues were assayed for H and heptachlor epoxide B (HEB), a major metabolite of H. The amount of H and HEB found in milk, blood, fat, and tissues was proportional to the dose of H administered. There were no effects on the number or survival of pups born to H-exposed dams nor to pups exposed postnatally. There were no effects on the number of treated dams delivering litters or on litter size, nor were there any effects on any of the reproductive end points examined in the F(0) or F(1) rats. There were no effects of H exposure on lymphoid organ weights, splenic natural killer (NK) cell activity, and splenic lymphoproliferative (LP) responses to mitogens and allogeneic cells in a mixed lymphocyte response (MLR) assay at 8 weeks of age. H exposure did not alter delayed or contact hypersensitivity at 10 or 17 weeks of age, respectively. However, the primary IgM antibody response to sheep red blood cells (SRBCs) was suppressed in a dose-dependent manner in males, but not females, at 8 weeks of age. The percentage of B lymphocytes (OX12(+)OX19(-)) in spleen was also reduced in the high-dose males. The anti-SRBC IgM response was reduced only in males exposed to 30 microg H/kg/day in a separate group of rats 21 weeks of age. In these same rats, at 26 weeks of age, the secondary IgG antibody response to SRBCs was suppressed in all of the H-exposed males, but not females. These data indicate that perinatal exposure of male rats to H results in suppression of the primary IgM and secondary IgG anti-SRBC responses. Suppression of these antibody responses persisted for up to 20 weeks after the last exposure to H, at a total exposure of approximately 1500 microg H/kg/rat.

Animals↗
PubMed2001

The effects of perinatal tebuconazole exposure on adult neurological, immunological, and reproductive function in rats.

Studies are under way to address concerns of potential persistent immunotoxic, reproductive, and neurotoxic effects of perinatal exposure to several pesticides. Tebuconazole, a triazole fungicide, was evaluated as part of this project. Sprague-Dawley dams were administered tebuconazole (0, 6, 20, or 60 mg/kg) by oral gavage daily from gestational day 14 to postnatal day (PND)7; the pups were then dosed daily at the same levels from PND7-42. Separate groups of rats were used for testing of immunological parameters, neurobehavioral testing using a screening battery of functional tests, and cognitive evaluations. Other groups of rats were evaluated for reproductive development and function, while yet others were sacrificed at the end of the dosing period for histological analyses of major organs systems, including neuropathological assessments. Pup viability and body weight were decreased in the highest dose group. There were no differences in the fertility indices in the exposed rats mated as adults. In the sheep RBC-immunized high-dose rats, spleen weights and cellularity were increased, and the ratio of cell types was altered compared to controls. There were, however, no biologically significant changes in the immune function of these rats. At necropsy on PND46 or 152, kidney, liver, and spleen weights were altered by tebuconazole treatment, but a dose-response relationship was not clear for most organs; only decreased kidney and increased liver weights were consistent in both sexes. Histological analyses were generally unremarkable outside of the brain. One month after the end of dosing, acquisition of learning the platform location in a water tank (i.e., Morris water maze) was impaired in the high-dose group; there were no differences in neuromuscular ability, motor activity, or swim speed to account for this finding. Furthermore, there was no effect on recall of the position during a free-swim trial. Neuropathological evaluations revealed pyknotic cells across hippocampal cell fields in animals of all tebuconazole treatment groups, with the highest incidence in the 20 and 60 mg/kg/day dose groups, coincident with cell loss within pyramidal cell layer of CA3-4 cell fields of the hippocampus and layer V of the neocortex. Thus, perinatal exposure to tebuconazole produced neurobehavioral deficits and neuropathology in rats, but did not alter immunological or reproductive function.

Animals↗
PubMed2001

A survey of heterobasidiomycetous yeasts for the presence of the genes homologous to virulence factors of Filobasidiella neoformans, CNLAC1 and CAP59.

Among species of the heterobasidiomycetous yeasts, Filobasidiella neoformans is the only serious pathogen that causes fatal infections in both immunocompromised as well as immunocompetent patients. Three phenotypic characteristics, including growth at 37 degrees C, extracellular polysaccharide capsule and laccase activity, of F. neoformans are known to play major roles in the pathogenicity of the fungus. Several CAP genes involved in polysaccharide capsule formation, as well as the CNLAC1 gene encoding a laccase, have previously been cloned and characterized. To analyse the presence of these Cryptococcus neoformans virulence factors in other heterobasidiomycetous yeasts, numerous species of heterobasidiomycetous yeasts were screened for the presence of laccase activity and a polysaccharide capsule. Species exhibiting laccase activity and possessing a glucuronoxylomannan (GXM) capsule were screened for homologues of both the CAP59 gene and the CNLAC1 gene of F. neoformans. Southern blots of genomic DNA from GXM capsule-producing species exhibited no discernible hybridization to the CAP59 DNA sequence except for the two varieties of F. neoformans and Cryptococcus podzolicus. Although discernible, the hybridization band observed with the DNA of C. podzolicus was faint. Oligonucleotide primers constructed using the CAP59 gene sequence also failed to yield PCR products from DNAs of these yeasts except for the two varieties of F. neoformans. These results, coupled with the absence of a CAP59 homologue in the database, suggested the CAP59 gene to be unique to F. neoformans. C. podzolicus was the only species besides F. neoformans that possessed a capsule and expressed strong laccase activity on various media containing phenolic compounds. A CNLAC1 homologue was isolated from C. podzolicus while it was not detected in the species producing beige to faint tan colonies on media with phenolic compounds. Compared to the CNLAC1 sequence of four serotypes of F. neoformans, the CNLAC1 homologue of C. podzolicus showed the highest homology to that of serotype B/C strains and the lowest homology to that of serotype A strains.

Basidiomycota↗
PubMed2001

3D localization of implanted radioactive sources in the prostate using trans-urethral ultrasound.

Prostate cancer is the most common cancer diagnosed in men in the United States. Many techniques have been developed to diagnose and treat prostate cancer. 3D Trans-Urethral Ultrasound (TUUS) is a new technique for the diagnosis and treatment of prostate disease. This research focuses on the potential of TUUS for therapy-guidance during and after transperineal interstitial permanent prostate brachytherapy (TIPPB). Computed tomography (CT) is currently used to determine the source locations and the effective radiation dose distribution throughout the tissue after the completion of the procedure. TUUS may be a viable alternative to CT for determining source locations within the prostate. Placement of the TUUS catheter into the urethra provides excellent 2D images of the prostate. In addition, the catheter can be used to acquire 3D volumetric data for 3D analysis of the prostate, associated tissue, and radioactive sources. Initial work on source localization was conducted on an ultrasound-equivalent prostate phantom. Cylindrical dummy radiation sources with diameter of .8 mm and length of 4.5 mm were placed into the prostate phantom for assessment with TUUS. The TUUS imaging device is a 10 fr catheter with a linear array of ultrasonic crystals at one end. The ultrasound catheter operates at 10 MHz and is controlled by the Acuson Sequoia ultrasound workstation. The catheter was placed in the phantom urethra and 3D scans were acquired. A corresponding CT was acquired for comparative purposes. Segmentation of the prostate capsule was done semi-automatically. Dummy radiation seed segmentation was conducted manually. Additional processing was necessary to account for image artifact and correctly reconstruct the seeds. The prostate shell and radioactive source reconstructions provide an excellent 3D representation. Comparison to the CT data suggests that the TUUS data provided: 1) greater resolution and 2) better soft tissue differentiation. The reconstructed sources were measured and corresponded to the physical dimensions of those placed in the phantoms. The method is now being evaluated on cadavers and patients.

Brachytherapy↗
PubMed2000

Proximity of prostate cancer to the urethra: implications for minimally invasive ablative therapies.

OBJECTIVES: The delivery of thermotherapy, cryotherapy, and interstitial radiation with minimal morbidity is dependent on the preservation of the prostatic urethra. Our aim was to determine the distribution of the distance between the urethra and the nearest prostate cancer. METHODS: We determined the location of cancer in 350 prostate cancers treated by radical prostatectomy between 1991 and 1993. Each pathologic specimen was totally embedded, serially sectioned, and whole mounted. For each prostate, the radial distance from the urethra to the nearest cancer was determined (urethral-cancer distance). The urethra-cancer distance was correlated with the clinical, pathologic, and laboratory factors. Univariate and multivariate associations with progression-free survival were determined. RESULTS: The mean follow-up was 6.1 years. Ninety-three patients had biochemical, local, or systemic cancer recurrence. The mean +/- SD distance from the urethra to the nearest cancer was 3 +/- 3 mm (range 0 to 18). In 58 patients (17%), the cancer touched the urethra. A decreasing urethra-cancer distance was associated with increasing rates of cancer recurrence (P = 0.009). The urethra-cancer distance correlated with each of the following preoperative factors: preoperative prostate-specific antigen (r = -0. 22, P <0.001), Gleason score in biopsy specimen (r = -0.13, P = 0.02), and percentage of Gleason score 4 or 5 in the biopsy specimen (r = -0.17, P = 0.008). CONCLUSIONS: The distance between the urethra and the nearest cancer was associated with prostate cancer outcome. Many patients have cancer close to the urethra. This finding may have implications for nonsurgical ablative therapies for prostate cancer.

Aged↗
PubMed2000

Ovarian tumors in rats induced by chronic 2,3,7,8-tetrachlorodibenzo-p-dioxin treatment.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a multispecies reproductive toxicant, and it has been recently classified by IARC as a known human carcinogen. Here, we report that TCDD promotes the development of ovarian tumors in an initiation-promotion model in female Sprague Dawley rats. Rats were initiated with diethylnitrosamine (DEN) or vehicle at 70 days of age. Starting 2 or 18 weeks after initiation, rats were exposed biweekly to TCDD at a daily average dose of 125 ng/kg/day for 14, 30, or 60 weeks continuously or for 30 weeks plus withdrawal periods of 16 or 30 weeks. Fifteen of 76 (20%) rats initiated with DEN and promoted with TCDD for various lengths of time developed ovarian sex cord-stromal tumors of Sertoli cell type, whereas no ovarian tumors developed in 86 rats used as vehicle controls or that received DEN alone or TCDD alone. The highest tumor incidence occurred in 6 of 14 rats (43%) after 60 weeks of continuous TCDD after DEN initiation. One of six rats developed a tumor by 30 weeks of exposure. Because most effects of TCDD can be attributed to its activation of the aryl hydrocarbon receptor (AhR), the presence and localization of AhR was determined in the rat ovary and in the ovarian tumors by reverse transcription-PCR, immunohistochemistry, and in situ hybridization. AhR was localized to oocytes, granulosa and thecal cells of growing follicles, surface epithelial cells, and epithelial cells lining single tubules in ovaries from adult control Sprague Dawley rats. Neoplastic cells in the ovarian tumors were also positive for both AhR message and protein. These results indicate that the ability of TCDD to cause ovarian tumors is dependent on initiation, length of promotion, and age of the animal when exposed and evaluated. The tumor type induced by TCDD in this experimental system is the same histological subtype as that reported from an early study of youngsters exposed during an industrial accident in Seveso, Italy.

Animals↗
PubMed2000

Mice heterozygous for a Brca1 or Brca2 mutation display distinct mammary gland and ovarian phenotypes in response to diethylstilbestrol.

Women who inherit mutations in the breast cancer susceptibility genes, BRCA1 and BRCA2, are predisposed to the development of breast and ovarian cancer. We used mice with a Brca1 mutation on a BALB/cJ inbred background (BALB/cB1+/- mice) or a Brca2 genetic alteration on the 129/SvEv genetic background (129B2+/- mice) to investigate potential gene-environment interactions between defects in these genes and treatment with the highly estrogenic compound diethylstilbestrol (DES). Beginning at 3 weeks of age, BALB/cB1+/-, 129B2+/-, and wild-type female mice were fed a control diet or a diet containing 640 ppb DES for 26 weeks. DES treatment caused vaginal epithelial hyperplasia and hyperkeratosis, uterine inflammation, adenomyosis, and fibrosis, as well as oviductal smooth muscle hypertrophy. The severity of the DES response was mouse strain specific. The estrogen-responsive 129/SvEv strain exhibited an extreme response in the reproductive tract, whereas the effect in BALB/cJ and C3H/HeN(MMTV-) mice was less severe. The Brca1 and Brca2 genetic alterations influenced the phenotypic response of BALB/cJ and 129/SvEv inbred strains, respectively, to DES in the mammary gland and ovary. The mammary duct branching morphology was inhibited in DES-treated BALB/cB1+/- mice compared with similarly treated BALB/cB1+/+ littermates. In addition, the majority of BALB/cB1+/- mice had atrophied ovaries, whereas wild-type littermates were largely diagnosed with arrested follicular development. The mammary ductal architecture in untreated 129B2+/- mice revealed a subtle inhibited branching phenotype that was enhanced with DES treatment. However, no significant differences were observed in ovarian pathology between 129B2+/+ and 129B2+/- mice. These data suggest that estrogenic compounds may modulate mammary gland or ovarian morphology in BALB/cB1+/- and 129B2+/- mice. These observations are consistent with the hypothesis that compromised DNA repair processes in cells harboring Brca1 or Brca2 mutations lead to inhibited growth and differentiation compared with the proliferative response of wild-type cells to DES treatment.

Animals↗
PubMed2000

BRCA2-null embryonic survival is prolonged on the BALB/c genetic background.

Women who inherit mutations in the BRCA2 cancer susceptibility gene have an 85% chance of developing breast cancer. The function of the BRCA2 gene remains elusive, but there is evidence to support its role in transcriptional transactivation, tumor suppression, and the maintenance of genomic integrity. Individuals with identical BRCA2 mutations display a different distribution of cancers, suggesting that there are low-penetrance genes that can modify disease outcome. We hypothesized that genetic background could influence embryonic survival of a Brca2 mutation in mice. Brca2-null embryos with a 129/SvEv genetic background (129(B2-/-)) died before embryonic day 8. 5. Transfer of this Brca2 mutation onto the BALB/cJ genetic background (BALB/c(B2-/-)) extended survival to embryonic day 10.5. These results indicate that the BALB/c background harbors genetic modifiers that can prolong Brca2-null embryonic survival. The extended survival of BALB/c(B2-/-) embryos enabled us to ask whether transcriptional regulation of the Brca1 and Brca2 genes is interdependent. The interdependence of Brca1 and Brca2 was evaluated by studying Brca2 gene expression in BALB/c(B1-/-) embryos and Brca1 gene expression in BALB/c(B2-/-) embryos. Nonisotopic in situ hybridization demonstrated that Brca2 transcript levels were comparable in BALB/c(B1-/-) embryos and wild-type littermates. Likewise, reverse transcriptase-polymerase chain reactions confirmed Brca1 mRNA expression in embryonic day 8.5 BALB/c(B2-/-) embryos that was comparable to Brca2-heterozygous littermates. Thus, the Brca1 and Brca2 transcripts are expressed independently of one another in Brca1- and Brca2-null embryos. Mol. Carcinog. 28:174-183, 2000.

Animals↗
PubMed2000

Telemedicine in radiotherapy treatment planning: requirements and applications.

BACKGROUND AND PURPOSE: Telemedicine facilitates decentralized radiotherapy services by allowing remote treatment planning and quality assurance of treatment delivery. A prerequisite is digital storage of relevant data and an efficient and reliable telecommunication system between satellite units and the main radiotherapy clinic. The requirements of a telemedicine system in radiotherapy is influenced by the level of support needed. In this paper we differentiate between three categories of telemedicine support in radiotherapy. RESULTS AND DISCUSSION: Level 1 features video conferencing and display of radiotherapy images and dose plans. Level 2 involves replication of selected data from the radiotherapy database - facilitating remote treatment planning and evaluation. Level 3 includes real-time, remote operations, e.g. target volume delineation and treatment planning performed by the team at the satellite unit under supervision and guidance from more experienced colleagues at the main clinic.

Humans↗
PubMed2000

Lessons from pregnancy and parturition: uterine leiomyomas result from discordant differentiation and dedifferentiation responses in smooth muscle cells.

Leiomyomas, benign smooth muscle tumors of the uterus, are the most common gynecological neoplasm in women. Studies with human tissues and primary cultures have revealed little about the development of leiomyomas, although several genes have been shown to be differentially expressed in leiomyomas compared to matched normal myometrium. We propose that uterine smooth muscle tumor cells mimic a differentiated myometrial cell of pregnancy, and are associated with a hypersensitivity to sex steroid hormones, preventing the cells from responding to normal apoptotic or dedifferentiation signals which would return the cells to a nongravid phenotype. Support of this hypothesis is derived from experimental studies in female Eker rats which develop uterine leiomyoma with many similarities to the human disease. Members of the steroid receptor superfamily as well as the binding partners and co-regulators necessary for transactivation and gene transcription, may be involved in the altered pathway of cellular differentiation and regulation observed in uterine leiomyomas.

Animals↗
PubMed2000

A randomized, double-blind placebo-controlled trial of iron in restless legs syndrome.

BACKGROUND: Previous open-label trials have shown iron to be efficacious in the treatment of restless legs syndrome. We performed a randomized, double-blind, placebo-controlled trial of iron sulfate. METHODS: Twenty-eight patients were randomized to receive either ferrous sulfate 325 mg b.i.d. or placebo for 12 weeks. The primary outcome measure was the dichotomous variable of improvement or no improvement in average quality of sleep as recorded by a visual analog scale nightly over a 2-week period, comparing a pretreatment 2-week baseline to weeks 13-14. Secondary outcome measures included a comparison of the quality of sleep as measured by a visual analog scale, effect of restless legs syndrome on life as a whole as measured by a different visual analog scale, and the percentage of nights patients were symptomatic. RESULTS: No significant differences were noted between iron and placebo groups for both primary and secondary outcome measures. Responders taking iron did have a significant increase in their iron saturation compared to nonresponders taking iron. CONCLUSIONS: Iron sulfate does not appear to be an effective empiric treatment for restless legs syndrome.

Adult↗