Li-Fraumeni syndrome fibroblasts homozygous for p53 mutations are deficient in global DNA repair but exhibit normal transcription-coupled repair and enhanced UV resistance.

We investigated whether mutations in the p53 tumor suppressor gene alter UV sensitivity and/or repair of UV-induced DNA damage in primary human skin fibroblasts from patients with Li-Fraumeni syndrome, heterozygous for mutations in one allele of the p53 gene (p53 wt/mut) and sublines expressing only mutant p53 (p53 mut). The p53 mut cells were more resistant than the p53 wt/mut cells to UV cytotoxicity and exhibited less UV-induced apoptosis. DNA repair analysis revealed reduced removal of cyclobutane pyrimidine dimers from overall genomic DNA in vivo in p53 mut cells compared with p53 wt/mut or normal cells. However, p53 mut cells retained the ability to preferentially repair damage in the transcribed strands of expressed genes (transcription-coupled repair). These results suggest that loss of p53 function may lead to greater genomic instability by reducing the efficiency of DNA repair but that cellular resistance to DNA-damaging agents may be enhanced through elimination of apoptosis.

Decreased atherosclerosis in mice deficient in both macrophage colony-stimulating factor (op) and apolipoprotein E.

To develop a murine model system to test the role of monocyte-derived macrophage in atherosclerosis, the osteopetrotic (op) mutation in the macrophage colony-stimulating factor gene was bred onto the apolipoprotein E (apoE)-deficient background. The doubly mutant (op/apoE-deficient) mice fed a low-fat chow diet had significantly smaller proximal aortic lesions at an earlier stage of progression than their apoE-deficient control littermates. These lesions in the doubly mutant mice were composed of macrophage foam cells. The op/apoE-deficient mice also had decreased body weights, decreased blood monocyte differentials, and increased mean cholesterol levels of approximately 1300 mg/dl. Statistical analysis determined that atherosclerosis lesion area was significantly affected by the op genotype and gender. The confounding variables of body weight, plasma cholesterol, and monocyte differential, which were all affected by op genotype, had no significant additional effect on lesion area once they were adjusted for the effects of op genotype and gender. Unexpectedly, there was a significant inverse correlation between plasma cholesterol and lesion area, implying that each may be the result of a common effect of macrophage colony-stimulating factor levels. The data support the hypothesis that macrophage colony-stimulating factor and its effects on macrophage development and function play a key role in atherogenesis.

Integration of transplanted hepatocytes into host liver plates demonstrated with dipeptidyl peptidase IV-deficient rats.

To analyze mechanisms of liver repopulation, we transplanted normal hepatocytes into syngeneic rats deficient in dipeptidyl peptidase IV activity. When isolated hepatocytes were injected into splenic pulp, cells promptly migrated into hepatic sinusoids. To examine whether transplanted hepatocytes entered liver plates and integrated with host hepatocytes, we analyzed sharing of hepatocyte-specific gap junctions and bile canaliculi. Colocalization studies showed gap junctions uniting adjacent transplanted and host hepatocytes in liver plates. Visualization of bile canalicular domains in transplanted and host hepatocytes with dipeptidyl peptidase IV and ATPase activities, respectively, demonstrated hybrid bile canaliculi, which excreted a fluorescent conjugated bile acid analogue. These results indicate that transplanted hepatocytes swiftly overcome mechanical barriers in hepatic sinusoids to enter liver plates and join host cells. Integration into liver parenchyma should physiologically regulate the function or disposition of transplanted hepatocytes and benefit applications such as gene therapy.

The protein deficient in Lowe syndrome is a phosphatidylinositol-4,5-bisphosphate 5-phosphatase.

Lowe syndrome, also known as oculocerebrorenal syndrome, is caused by mutations in the X chromosome-encoded OCRL gene. The OCRL protein is 51% identical to inositol polyphosphate 5-phosphatase II (5-phosphatase II) from human platelets over a span of 744 aa, suggesting that OCRL may be a similar enzyme. We engineered a construct of the OCRL cDNA that encodes amino acids homologous to the platelet 5-phosphatase for expression in baculovirus-infected Sf9 insect cells. This cDNA encodes aa 264-968 of the OCRL protein. The recombinant protein was found to catalyze the reactions also carried out by platelet 5-phosphatase II. Thus OCRL converts inositol 1,4,5-trisphosphate to inositol 1,4-bisphosphate, and it converts inositol 1,3,4,5-tetrakisphosphate to inositol 1,3,4-trisphosphate. Most important, the enzyme converts phosphatidylinositol 4,5-bisphosphate to phosphatidylinositol 4-phosphate. The relative ability of OCRL to catalyze the three reactions is different from that of 5-phosphatase II and from that of another 5-phosphatase isoenzyme from platelets, 5-phosphatase I. The recombinant OCRL protein hydrolyzes the phospholipid substrate 10- to 30-fold better than 5-phosphatase II, and 5-phosphatase I does not cleave the lipid at all. We also show that OCRL functions as a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in OCRL-expressing Sf9 cells. These results suggest that OCRL is mainly a lipid phosphatase that may control cellular levels of a critical metabolite, phosphatidylinositol 4,5-bisphosphate. Deficiency of this enzyme apparently causes the protean manifestations of Lowe syndrome.

A kinase-deficient transcription factor TFIIH is functional in basal and activated transcription.

Phosphorylation of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II has been suggested to be critical for transcription initiation, activation, or elongation. A kinase activity specific for CTD is a component of the general transcription factor TFIIH. Recently, a cyclin-dependent kinase-activator kinase (MO15 and cyclin H) was found to be associated with TFIIH preparations and was suggested to be the CTD kinase. TFIIH preparations containing mutant, kinase-deficient MO15 lack CTD kinase activity, indicating that MO15 is critical for polymerase phosphorylation. Nonetheless, these mutant TFIIH preparations were fully functional (in vitro) in both basal and activated transcription. These results indicate that CTD phosphorylation is not required for transcription with a highly purified system.

Number of discernible colors for color-deficient observers estimated from the MacAdam limits

We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65, and the resultant colors were expressed in the CIELAB and DIN99d color spaces. The corresponding color volumes for abnormal color vision were computed using models simulating for normal trichromatic observers the appearance for dichromats and anomalous trichomats. The number of colors perceived in each case was then computed from the color volumes enclosed by the optimal colors also known as MacAdam limits. It was estimated that dichromats perceive less than 1% of the colors perceived by normal trichromats and that anomalous trichromats perceive 50%–60% for anomalies in the medium-wavelength-sensitive and 60%–70% for anomalies in the long-wavelength-sensitive cones. Complementary estimates obtained similarly for the spectral locus of monochromatic stimuli suggest less impairment for color-deficient observers, a fact that is explained by the two-dimensional nature of the locus.

Effects of high-color-discrimination capability spectra on color-deficient vision

Light sources with three spectral bands in specific spectral positions are known to have high-color-discrimination capability. W. A. Thornton hypothesized that they may also enhance color discrimination for color-deficient observers. This hypothesis was tested here by comparing the Rösch–MacAdam color volume for color-deficient observers rendered by three of these singular spectra, two reported previously and one derived in this paper by maximization of the Rösch–MacAdam color solid. It was found that all illuminants tested enhance discriminability for deuteranomalous observers, but their impact on other congenital deficiencies was variable. The best illuminant was the one derived here, as it was clearly advantageous for the two red–green anomalies and for tritanopes and almost neutral for red–green dichromats. We conclude that three-band spectra with high-color-discrimination capability for normal observers do not necessarily produce comparable enhancements for color-deficient observers, but suitable spectral optimization clearly enhances the vision of the color deficient.

Interleukin-6-deficient mice are highly susceptible to Giardia lamblia infection but exhibit normal intestinal immunoglobulin A responses against the parasite.

In the present study, interleukin-6 (IL-6)-deficient mice were infected with Giardia lamblia clone GS/M-83-H7. Murine IL-6 deficiency did not affect the synthesis of parasite-specific intestinal immunoglobulin A. However, in contrast to wild-type mice, IL-6-deficient animals were not able to control the acute phase of parasite infection. Reverse transcription-PCR-based quantitation of cytokine mRNA levels in peripheral lymph node cells exhibited a short-term up-regulation of IL-4 expression in IL-6-deficient mice that seemed to be associated with failure in controlling the parasite population. This observation suggests a further elucidation of IL-4-dependent, Th2-type regulatory processes regarding their potential to influence the course of G. lamblia infection in the experimental murine host.

Mice deficient in interleukin-4 (IL-4) or IL-4 receptor alpha have higher resistance to sporozoite infection with Plasmodium berghei (ANKA) than do naive wild-type mice

BALB/c interleukin-4 (IL-4(-/-)) or IL-4 receptor-alpha (IL-4ralpha(-/-)) knockout (KO) mice were used to assess the roles of the IL-4 and IL-13 pathways during infections with the blood or liver stages of plasmodium in murine malaria. Intraperitoneal infection with the blood-stage erythrocytes of Plasmodium berghei (ANKA) resulted in 100% mortality within 24 days in BALB/c mice, as well as in the mutant mouse strains. However, when infected intravenously with the sporozoite liver stage, 60 to 80% of IL-4(-/-) and IL-4ralpha(-/-) mice survived, whereas all BALB/c mice succumbed with high parasitemia. Compared to infected BALB/c controls, the surviving KO mice showed increased NK cell numbers and expression of inducible nitric oxide synthase (iNOS) in the liver and were able to eliminate parasites early during infection. In vivo blockade of NO resulted in 100% mortality of sporozoite-infected KO mice. In vivo depletion of NK cells also resulted in 80 to 100% mortality, with a significant reduction in gamma interferon (IFN-gamma) production in the liver. These results suggest that IFN-gamma-producing NK cells are critical in host resistance against the sporozoite liver stage by inducing NO production, an effective killing effector molecule against Plasmodium. The absence of IL-4-mediated functions increases the protective innate immune mechanism identified above, which results in immunity against P. berghei infection in these mice, with no major role for IL-13.

Genetically attenuated, P36p-deficient malarial sporozoites induce protective immunity and apoptosis of infected liver cells.

Immunization with Plasmodium sporozoites that have been attenuated by gamma-irradiation or specific genetic modification can induce protective immunity against subsequent malaria infection. The mechanism of protection is only known for radiation-attenuated sporozoites, involving cell-mediated and humoral immune responses invoked by infected hepatocytes cells that contain long-lived, partially developed parasites. Here we analyzed sporozoites of Plasmodium berghei that are deficient in P36p (p36p(-)), a member of the P48/45 family of surface proteins. P36p plays no role in the ability of sporozoites to infect and traverse hepatocytes, but p36p(-) sporozoites abort during development within the hepatocyte. Immunization with p36p(-) sporozoites results in a protective immunity against subsequent challenge with infectious wild-type sporozoites, another example of a specifically genetically attenuated sporozoite (GAS) conferring protective immunity. Comparison of biological characteristics of p36p(-) sporozoites with radiation-attenuated sporozoites demonstrates that liver cells infected with p36p(-) sporozoites disappear rapidly as a result of apoptosis of host cells that may potentiate the immune response. Such knowledge of the biological characteristics of GAS and their evoked immune responses are essential for further investigation of the utility of an optimized GAS-based malaria vaccine.

The psychology of mentally deficient children,

Columbia University contributions to philosophy and psychology, vol. XV, no. 2.

Educationally deficient adults : their education and training needs /

Reprint of the 1964 ed. published by McGraw-Hill. N. Y.

Feasibility of developing training programs designed to improve deficient driver factors. Volume I: a review of existing data bases and recommendations for future data collection. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Feasibility of developing training programs designed to improve deficient driver factors. Volume II: identifying accident avoidance behaviors: a guide for accident investigators. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Deficient generalized Fibonacci maximum path graphs /

"UILU-ENG 78 1739."