A subset of p53-deficient embryos exhibit exencephaly.

Defects in neural tube formation are among the most common malformations leading to infant mortality. Although numerous genetic loci appear to contribute to the defects observed in humans and in animal model systems, few of the genes involved have been characterized at the molecular level. Mice lacking the p53 tumour suppressor gene are predisposed to tumours, but the viability of these animals indicates that p53 function is not essential for embryonic development. Here, we demonstrate that a fraction of p53-deficient embryos in fact do not develop normally. These animals display defects in neural tube closure resulting in an overgrowth of neural tissue in the region of the mid-brain, a condition known as exencephaly.

Skeletal muscle cells lacking the retinoblastoma protein display defects in muscle gene expression and accumulate in S and G2 phases of the cell cycle.

Viral oncoproteins that inactivate the retinoblastoma tumor suppressor protein (pRb) family both block skeletal muscle differentiation and promote cell cycle progression. To clarify the dependence of terminal differentiation on the presence of the different pRb-related proteins, we have studied myogenesis using isogenic primary fibroblasts derived from mouse embryos individually deficient for pRb, p107, or p130. When ectopically expressed in fibroblasts lacking pRb, MyoD induces an aberrant skeletal muscle differentiation program characterized by normal expression of early differentiation markers such as myogenin and p21, but attenuated expression of late differentiation markers such as myosin heavy chain (MHC). Similar defects in MHC expression were not observed in cells lacking either p107 or p130, indicating that the defect is specific to the loss of pRb. In contrast to wild-type, p107-deficient, or p130-deficient differentiated myocytes that are permanently withdrawn from the cell cycle, differentiated myocytes lacking pRb accumulate in S and G2 phases and express extremely high levels of cyclins A and B, cyclin-dependent kinase (Cdk2), and Cdc2, but fail to readily proceed to mitosis. Administration of caffeine, an agent that removes inhibitory phosphorylations on inactive Cdc2/cyclin B complexes, specifically induced mitotic catastrophe in pRb-deficient myocytes, consistent with the observation that the majority of pRb-deficient myocytes arrest in S and G2. Together, these findings indicate that pRb is required for the expression of late skeletal muscle differentiation markers and for the inhibition of DNA synthesis, but that a pRb-independent mechanism restricts entry of differentiated myocytes into mitosis.

Lupinus arcticus Wats. Grown from Seeds of Pleistocene Age.

Seeds of the arctic tundra lupine (Lupinus arcticus) at least 10,000 years old were found in lemming burrows deeply buried in permanently frozen silt of Pleistocene age in unglaciated central Yukon. They readily germinated in the laboratory and have since grown into normal, healthy plants.

The retinoblastoma gene family: cousins with overlapping interests.

The retinoblastoma tumor suppressor gene (RB1) and its relatives, p107 and p130, encode a family of proteins that share several properties, including the capacity to regulate E2F-dependent transcription and inhibit cell-cycle progression. Although RB1 inactivation is widely implicated in human cancer, the growth regulatory functions of p107 and p130, and the functional relationships within the gene family, are emerging only recently. Here we review studies of RB1 gene family function, with emphasis on in vivo experiments that explore shared and distinct functions within this family.

p130 is dispensable in peripheral T lymphocytes: evidence for functional compensation by p107 and pRB.

The proteins encoded by the retinoblastoma gene family, pRB, p107, and p130, have been implicated in the regulation of cellular proliferation, differentiation, and transformation. Because interactions between p130 and E2F transcription factors have been proposed to play a role in the establishment and/or maintenance of quiescence in human peripheral T lymphocytes, we examined lymphoid differentiation and proliferation in p130-deficient mice. We show that p130-/- T cells proliferate normally in culture and exhibit normal cell-mediated immune function in vivo. However, p130-/- T lymphocytes expressed elevated levels of p107, and the characteristic p130-E2F DNA binding complex was replaced by a p107-E2F complex. Adoptive transfer of fetal liver lymphoid progenitors allowed us to circumvent the neonatal lethality associated with loss of p130 and p107 and to analyze the phenotype of p130-/-;p107-/- peripheral T lymphocytes. These cells achieved a quiescent state, exhibited derepression of a subset of E2F target genes, and were hypersensitive to concanavalin A stimulation. Interestingly, a significant portion of the E2F-4 in p130-/-;p107-/- T cells was detected in a complex with pRB and an as-yet-unidentified protein. These findings provide a biochemical basis for functional compensation between pRB family proteins.

RPL5 on 1p22.1 is recurrently deleted in multiple myeloma and its expression is linked to bortezomib response.

Chromosomal region 1p22 is deleted in ⩾20% of multiple myeloma (MM) patients, suggesting the presence of an unidentified tumor suppressor. Using high-resolution genomic profiling, we delimit a 58 kb minimal deleted region (MDR) on 1p22.1 encompassing two genes: ectopic viral integration site 5 (EVI5) and ribosomal protein L5 (RPL5). Low mRNA expression of EVI5 and RPL5 was associated with worse survival in diagnostic cases. Patients with 1p22 deletion had lower mRNA expression of EVI5 and RPL5, however, 1p22 deletion status is a bad predictor of RPL5 expression in some cases, suggesting that other mechanisms downregulate RPL5 expression. Interestingly, RPL5 but not EVI5 mRNA levels were significantly lower in relapsed patients responding to bortezomib and; both in newly diagnosed and relapsed patients, bortezomib treatment could overcome their bad prognosis by raising their progression-free survival to equal that of patients with high RPL5 expression. In conclusion, our genetic data restrict the MDR on 1p22 to EVI5 and RPL5 and although the role of these genes in promoting MM progression remains to be determined, we identify RPL5 mRNA expression as a biomarker for initial response to bortezomib in relapsed patients and subsequent survival benefit after long-term treatment in newly diagnosed and relapsed patients.

Dual pathways of calcium entry in spike and plateau phases of luteinizing hormone release from chicken pituitary cells: sequential activation of receptor-operated and voltage-sensitive calcium channels by gonadotropin-releasing hormone.

It has previously been shown that, in pituitary gonadotrope cells, the initial rise in cytosolic Ca2+ induced by GnRH is due to a Ca2+ mobilization from intracellular stores. This raises the possibility that the initial transient spike phase of LH release might be fully or partially independent of extracellular Ca2+. We have therefore characterized the extracellular Ca2+ requirements, and the sensitivity to Ca2+ channel blockers, of the spike and plateau phases of secretion separately. In the absence of extracellular Ca2+ the spike and plateau phases were inhibited by 65 +/- 4% and 106 +/- 3%, respectively. Both phases exhibited a similar dependence on concentration of extracellular Ca2+. However, voltage-sensitive Ca2+ channel blockers D600 and nifedipine had a negligible effect on the spike phase, while inhibiting the plateau phase by approximately 50%. In contrast, ruthenium red, Gd3+ ions, and Co2+ ions inhibited both spike and plateau phases to a similar extent as removal of extracellular Ca2+. A fraction (35 +/- 4%) of spike phase release was resistant to removal of extracellular Ca2+. This fraction was abolished after calcium depletion of the cells by preincubation with EGTA in the presence of calcium ionophore A23187, indicating that it depends on intracellular Ca2+ stores. Neither absence of extracellular Ca2+, nor the presence of ruthenium red or Gd3+ prevented mobilization of 45Ca2+ from intracellular stores by GnRH. We conclude that mobilization of intracellular stored Ca2+ is insufficient by itself to account for full spike phase LH release.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroid function and treatment in premenstrual syndrome.

In 1986 it was reported that a high percentage of women with premenstrual syndrome (PMS) were found to have thyroid hypofunction (TH), mostly subclinical hypothyroidism, as defined by an augmented response of TSH to TRH, and that all affected women had complete relief of PMS symptoms with L-T4 therapy. We studied baseline thyroid function (T4, T3 uptake, T3, TSH, and TSH response to TRH) in 15 normal women (group 1) and 44 women with PMS and treated 22 of the PMS women with L-T4 (group 2; 1.6 micrograms L-T4/kg dose) and the other half with placebo (group 3) for 2 months in a double blinded protocol. We found no evidence of thyroid dysfunction in group 2 or 3, except for 1 subject with slightly elevated TSH (6.2 microIU/mL) and moderate augmented response to TRH (change in TSH, 65 microIU/mL). During the treatment phase we found a complete relief of symptoms in 6 (27%), a partial relief of symptoms in 6 (27%), and some relief of symptoms in 12 (54%) in group 2. Whereas in group 3, 10 (45%) had complete relief, 5 (23%) had partial relief, and 15 (68%) had some relief of symptoms. These results show that 1) there is no significant thyroid disease in PMS; and 2) L-T4 is no better than placebo in treatment of PMS. We conclude that the high incidence of thyroid hypofunction previously reported in PMS is due to an unusually low TSH level for the limit of the normal range for the TRH stimulation test.

Subepithelial corneal deposits in IgG lambda myeloma.

A 46-year-old female presented with disseminated IgG lambda myeloma and unusual, translucent, subepithelial deposits in the periphery of both corneas. Electrophoretic studies showed that the deposits consisted of an IgG lambda paraprotein identical to that found in the serum. Minute amounts of the papaprotein were also present in the tears.

Labor migration amongst hierarchically competing and intervening origins and destinations.

"A spatial interaction methodology is developed for modeling flows in a hierarchical system. A competing and intervening destinations framework is employed to model and predict U.S. state-to-state labor migration. This analysis is used to assess the importance of geographic variables in explaining variations in regional labor flows. Empirical findings suggest that U.S. labor migration is largely explained by...size, distance, locational accessibility, and intervening opportunities in a spatial hierarchy. It is also suggested that lagged migration or migrant stock is a product of the combined effect of these forces."

A gene expression signature for high-risk multiple myeloma.

There is a strong need to better predict the survival of patients with newly diagnosed multiple myeloma (MM). As gene expression profiles (GEPs) reflect the biology of MM in individual patients, we built a prognostic signature based on GEPs. GEPs obtained from newly diagnosed MM patients included in the HOVON65/GMMG-HD4 trial (n=290) were used as training data. Using this set, a prognostic signature of 92 genes (EMC-92-gene signature) was generated by supervised principal component analysis combined with simulated annealing. Performance of the EMC-92-gene signature was confirmed in independent validation sets of newly diagnosed (total therapy (TT)2, n=351; TT3, n=142; MRC-IX, n=247) and relapsed patients (APEX, n=264). In all the sets, patients defined as high-risk by the EMC-92-gene signature show a clearly reduced overall survival (OS) with a hazard ratio (HR) of 3.40 (95% confidence interval (CI): 2.19-5.29) for the TT2 study, 5.23 (95% CI: 2.46-11.13) for the TT3 study, 2.38 (95% CI: 1.65-3.43) for the MRC-IX study and 3.01 (95% CI: 2.06-4.39) for the APEX study (P<0.0001 in all studies). In multivariate analyses this signature was proven to be independent of the currently used prognostic factors. The EMC-92-gene signature is better or comparable to previously published signatures. This signature contributes to risk assessment in clinical trials and could provide a tool for treatment choices in high-risk MM patients.

Clinical and biological implications of MYC activation: a common difference between MGUS and newly diagnosed multiple myeloma.

Events mediating transformation from the pre-malignant monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) are unknown. We analyzed gene expression data sets generated on the Affymetrix U133 platform from 22 MGUS and 101 MM patients using gene-set enrichment analysis. Genes overexpressed in MM were enriched for cell cycle, proliferation and MYC activation gene sets. Upon dissecting the relationship between MYC and cell-cycle gene sets, we identified and validated an MYC activation signature dissociated from proliferation. Applying this signature, MYC is activated in 67% of myeloma, but not in MGUS. This was further confirmed by immunohistochemistry (IHC) using membrane CD138 and nuclear MYC double staining. We also showed that almost all tumors with RAS mutations expressed the MYC activation signature, and multiple mechanisms may be involved in activating MYC. MYC activation, whether assessed by gene-expression signature or IHC, is associated with hyperdiploid MM and shorter survival even in tumors that are not proliferative. Bortezomib treatment is able to overcome the survival disadvantage in patients with MYC activation.

Exercise-associated hyponatremia, renal function, and nonsteroidal antiinflammatory drug use in an ultraendurance mountain run.

OBJECTIVE: To study biochemical parameters and renal function in runners completing a 60 km mountain run and to investigate the incidence of exercise-associated hyponatremia (EAH). To assess the effects of nonselective nonsteroidal antiinflammatory medication (NSAIDs) and cyclooxygenase-2 (COX-2) selective nonsteroidal antiinflammatory medication (COXIBs) on these parameters. DESIGN: Observational cohort study. SETTING: Kepler Challenge 60 km mountain run, Te Anau, New Zealand, December 2003. PARTICIPANTS: One hundred thirty-one of the 360 runners entered in the race were prospectively enrolled as volunteers on the day before the race. MAIN OUTCOME MEASURES: Subjects were weighed at race registration the day before the race and at the finish line. Blood was taken within 5 minutes of finishing and was analyzed for serum sodium, creatinine, urea, and potassium concentrations, and hematocrit. Participants were questioned about medication use in the 24 hours before and during the race (NSAIDs, COXIBs, other medications). RESULTS: Complete data sets were obtained on 123 runners. Five athletes were biochemically hyponatremic [(Na) 130-134 mM] and four were hypernatremic [(Na) 146-148 mM]. Hyponatremia was associated with a mean weight gain of 1.32 kg (range, -1.5 to 1.6 kg). Serum [Na] varied inversely with weight change. Estimated creatinine clearance did not vary with percent weight loss. Estimated creatinine clearance declined with increasing runner age. Sixty-five percent of runners did not use any medication, whereas 20% had used NSAIDs and 15% had taken COXIBs. There were no statistically significant differences between NSAID and COXIB users in any measured parameters or between all NSAID and COXIB users when compared with nonusers. CONCLUSIONS: Mild asymptomatic EAH was found to occur in 4% of the volunteer ultraendurance mountain runner study group and was associated with a mean weight gain of 1.32 kg (range, -1.5 to 1.6 kg) during the race. Seven percent gained weight but remained normonatremic, suggesting other compensatory mechanisms. Hypernatremia was found in 3% and was associated with a mean weight loss. Postrace serum sodium concentration varied inversely with percent weight change. Runners using any NSAID were more likely to become hyponatremic. Estimated creatinine clearance increased with increasing age. Elevated serum creatinine concentration at the end of the race returned to normal when remeasured the week after the race. Thirty-five percent of runners were found to use NSAIDs or COXIBs. The measures of weight change and of serum sodium, potassium, urea, and creatine concentration did not differ between NSAID and COXIB users or between all nonsteroidal antiinflammatory users and nonusers.

Increase in lactate dehydrogenase isoenzyme-1 in plasma in pediatric malignancy.

We investigated 28 cases of pediatric malignancy in which total lactate dehydrogenase (LD, EC 1.1.1.27) activities were increased and isoenzyme LD-1 exceeded LD-2 (flipped pattern). Of these, 11 had a flipped pattern at presentation and 17 showed a flipped pattern during chemotherapy. Those with flipped patterns at presentation were four with germ-cell tumors, one with acute lymphocytic leukemia, and six with nephroblastomas (Wilms tumor). Four of five nephroblastoma homogenates contained predominantly LD-1; one revealed a structurally normal LD-1 with normal kinetics. We conclude that an increase in LD with a flipped pattern is common in nephroblastoma and, in addition, may develop in cancer patients treated with chemotherapy.

Measuring spatial focusing in a migration system.

Equality indexes used in other geographical contexts may be used to gauge the degree of spatial focusing in an entire migration system or within the gross in- and out-migration fields of specific regions. They provide useful indicators of overall shifts in the patterns of interregional migration and can help give insight into the population redistributive roles played by specific regions. Perhaps the most common equality index used to measure income distribution is the Gini coefficient, yet it appears almost never to have been applied in migration research. In this paper we set forth a variety of Gini indexes to be used for different migration analyses and illustrate their application with recent data on U.S. interstate movements. We argue that the Gini index provides some singularly useful insights that differ from those afforded by other measures more commonly found to date in the migration analyst's tool kit.

3-dimensional computerized tomographic reconstruction of colovesical fistulas.

PURPOSE: Use of 3-dimensional tomographic reconstruction in evaluating colovesical fistulas is discussed. MATERIALS AND METHODS: We compared 3-dimensional computerized tomographic (CT) images of colovesical fistulas to conventional CT images. RESULTS: Successful surgical repair was facilitated by preoperative radiographic data. CONCLUSIONS: Three-dimensional CT reconstruction provides superior spacial detail and can clarify complex anatomical relationships preoperatively.

Current status of small-bowel ultrasound.

Ultrasonography offers direct imaging of the bowel wall and allows dynamic evaluation of peristalsis. It helps to differentiate eosinophilic gastroenteritis from regional enteritis and lymphoma, displays a typical appearance in intussusception and is quite specific in the afferent loop syndrome, closed-loop obstruction and lymphedema. It may be helpful in ischemia of the bowel and in the evaluation of acute appendicitis.