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Biomedical subjects

M Caruso

Publications and source records attributed to M Caruso.

At least 19 recordsLinked to original sources
PubMed1992

Selective killing of CD4+ cells harboring a human immunodeficiency virus-inducible suicide gene prevents viral spread in an infected cell population.

We have stably expressed in CD4+ lymphoid cells the herpes simplex virus type 1 thymidine kinase (HSV1-TK) gene under the control of the human immunodeficiency virus (HIV) promoter and transactivation response element sequences. Upon HIV infection these regulatory sequences were transactivated, switching on high-level expression of HSV1-TK. This in turn caused the death of HIV-infected cells when they were cultured in the presence of acyclovir, a nucleoside analog that becomes toxic after phosphorylation by HSV1-TK. The elimination of HIV-infected cells resulted in the arrest of HIV spreading in the culture. Complete protection of HSV1-TK-expressing cells was obtained using acyclovir concentrations that are commonly detected in the plasma of patients treated for HSV1 infection. Thus, expression of this DNA construct generates a pool of CD4+ booby-trapped cells that, as a population, are resistant to HIV infection. Our data provide a rationale for the use of suicide genes in the design of gene therapy of HIV infection.

Acyclovir↗
PubMed1992

Expression of doxorubicin-daunorubicin resistance genes in different anthracycline-producing mutants of Streptomyces peucetius.

Two DNA fragments, ric1 and ric2, were isolated from the Streptomyces peucetius 7600 mutant, which produces daunorubicin and doxorubicin, on the basis of their abilities to confer doxorubicin and daunorubicin resistance to Streptomyces lividans. These two fragments are unrelated by restriction mapping and do not show any homology by Southern analysis, yet both of them increase the level of resistance 10-fold in transformed S. lividans. Functional analysis revealed that ric1 also contains two genes of daunorubicin biosynthesis: one coding for the aklavinone C-11 hydroxylase and the other corresponding to the putative dnrR2 regulatory gene of wild-type S. peucetius ATCC 29050 (K. J. Stutzman-Engwall, S. L. Otten, and C. R. Hutchinson, J. Bacteriol. 174:144-154, 1992). Northern (RNA) blot experiments, performed with a ric1 fragment containing daunorubicin-doxorubicin resistance gene(s), revealed a transcript of about 2,100 nucleotides that is present only during the phase of anthracycline metabolite production. The amount of this transcript is higher in strain 7600 than in strain 7900, a mutant which produces 5-fold more daunorubicin and 10-fold less doxorubicin than 7600. Furthermore, two 7900-derived blocked mutants, 8600 and 9700, do not express the 2,100-nucleotide transcript in spite of the absence of gross rearrangements in the ric1 region such as occur with the 7900 parental strain.

Cloning, Molecular↗
PubMed1992

[Treatment of experimental liver tumors by in vivo suicide gene transfer in rats].

We investigated whether the transduction of a suicide gene might induce the elimination of malignant solid tumours. BDIX male rats were given an intra-hepatic injection of a mixture containing DHDK12 tumor cells and xenogeneic fibroblasts. The latter were producing either the herpes simplex virus type 1 thymidine kinase HSV1-TK- or nls-lac Z(control)-expressing recombinant retroviral particles. 5 days later, a time at which the tumor is macroscopic, all the rats were treated with ganciclovir, a nucleoside analog that is metabolized by HSV1-TK into a toxic compound. After 5 days of treatment, a dramatic reduction in tumour volume was noted in the HSV1-TK group. These results delineate a new therapeutical strategy for the treatment of disseminated liver metastases or of a large variety of solid malignant tumours.

Animals↗
PubMed1990

Protein recognition sites in polyomavirus enhancer: formation of a novel site for NF-1 factor in an enhancer mutant and characterization of a site in the enhancer D domain.

Polyomavirus mutants selected for modified host range exhibit DNA sequence alterations in the regulatory region, which consist mainly of duplications and/or deletions. Single base pair mutations have also been observed, which create or abolish DNA sequence motifs recognized by DNA-binding regulatory factors. The present work deals with the molecular characterization of a Polyoma mutant (PyNB11/1), selected for its high efficiency of growth in neuroblastoma cells. The enhancer region of PyNB11/1 displays a 91 bp tandem duplication harbouring a novel DNA sequence motif created at the boundary of the duplicated fragment. This motif is absent in the wild-type enhancer and is specifically recognized by a nuclear factor that belongs to the NF-1 family of transcription factors. We also report the characterization of an as yet unidentified DNA sequence motif in the D domain of the viral enhancer, that represents the binding site for a nuclear factor that is ubiquitous and comparably abundant in several murine cell types.

Animals↗
PubMed1990

Lack of effect of hyperglycemia on lipolysis in humans.

Controversy exists regarding whether plasma glucose concentrations are independently involved in the regulation of adipose tissue lipolysis. In the present study, six subjects with insulin-dependent diabetes and six nondiabetic volunteers were studied during infusion of somatostatin, growth hormone, and insulin at rates designed to maintain basal rates of lipolysis, which was traced using a constant infusion of [1-14C]palmitate. A euglycemic (approximately 5 mmol/l) clamp was performed for 3 h, followed by 3 h of hyperglycemia (approximately 9 and approximately 11 mmol/l in nondiabetic and diabetic subjects, respectively). Ten nondiabetic subjects were studied during 6 h of euglycemia to exclude time-dependent changes in lipolysis. The results showed that palmitate concentrations did not change between euglycemia and hyperglycemia in either group [118 +/- 10 vs. 132 +/- 14 mumol/l and 145 +/- 21 vs. 134 +/- 15 mumol/l in nondiabetic and diabetic subjects, respectively; both P = not significant (NS)]. Similarly, palmitate rate of appearance (Ra) did not change during hyperglycemia (1.0 +/- 0.1 and 1.7 +/- 0.4 mumol.kg-1.min-1 in nondiabetic and diabetic subjects, respectively) compared with euglycemia (1.0 +/- 0.1 and 1.6 +/- 0.4 mumol.kg-1.min-1 in nondiabetic and diabetic subjects, respectively; P = NS). Palmitate concentrations and Ra did not change during 6 h of euglycemia in nondiabetic volunteers. Thus hyperglycemia per se has no effect on free fatty acid turnover. Changes in lipolysis that occur coincident with hyperglycemia are probably due to changes in other circulating substrates or hormones known to affect lipolysis.

Adult↗
PubMed1989

Mouse genes coding for "zinc-finger"-containing proteins: characterization and expression in differentiated cells.

By using the zinc-finger region of human cHF.10 cDNA as a probe at low-stringency hybridization conditions, several individual phages from a mouse skeletal muscle cDNA library have been isolated. The amino acid sequences of the "zinc-finger" domains derived from the DNA sequences of three cDNA clones are shown. The expression of the corresponding mRNAs in three cell lines (NIH 3T3, F9 teratocarcinoma, and C2 myoblast cells) at different stages of differentiation and in eight adult mouse tissues has been analyzed. The transcription of these genes is induced during the in vitro differentiation of the cell lines tested. These three genes are widely and evenly expressed in adult mouse tissues, with the remarkable exception of one that is expressed predominantly in the testis.

Amino Acid Sequence↗
PubMed1989

Polyomavirus genome and polyomavirus enhancer-driven gene expression during myogenesis.

The mRNAs for myogenic functions are coordinately transcribed with polyomavirus (Py) early mRNA during in vitro differentiation of mouse C2 myoblast cells. Sequence analysis shows that the A domain of the Py enhancer includes an E1A-like consensus sequence that is also found in the 5' upstream region of two genes expressed during myoblast differentiation: alpha-actin and myosin light chain. Therefore, the coordinate expression of such genes with Py early mRNA may be activated by a common cellular regulatory factor. In the present work, we report that C2 cells surviving Py infection are unable to differentiate and do not express alpha-actin and myosin light-chain mRNAs. Hybrids between such Py-resistant myoblast cells and the parental cells exhibited dominance of the permissibility to Py growth and of the expression of myogenic mRNAs. In C2 cells transiently transfected with a chimeric plasmid (pSVPy12CAT) harboring the bacterial chloramphenicol acetyltransferase (CAT) gene driven by the Py enhancer-promoter region, the CAT gene was expressed irrespective of their stage of differentiation. Moreover, undifferentiated stably transfected cells expressing the CAT gene restricted viral growth. Py-resistant C2 myoblasts transiently transfected with pSVPy12CAT also expressed the CAT gene driven by the Py enhancer. This contradictory finding is similar to results previously obtained by other investigators with cloned genes specific for myogenic functions, and it may be explained by a structural difference between the pSVPy12CAT and the Py genomic organizations in which the viral enhancer operates.

Animals↗
PubMed1989

Insulin regulation of lipolysis in nondiabetic and IDDM subjects.

To determine whether insulin regulation of lipolysis is abnormal in subjects with poorly controlled insulin-dependent diabetes mellitus (IDDM), free-fatty acid flux ([1-14C]palmitate) was measured under conditions ranging from complete insulin withdrawal to hyperinsulinemia. Seven nondiabetic and seven IDDM subjects were studied with the pancreatic clamp technique to control plasma insulin, growth hormone, and glucagon concentrations at the desired levels. Preliminary studies were performed to validate the experimental design. The palmitate flux response to insulin withdrawal (2.5 +/- 0.2 vs. 2.5 +/- 0.2 mumol.kg-1.min-1) and maximally antilipolytic insulin concentrations (0.17 +/- 0.02 vs. 0.23 +/- 0.03 mumol.kg-1.min-1) were not different in nondiabetic and IDDM subjects, respectively. In contrast, IDDM subjects required significantly greater plasma free-insulin concentrations to result in equivalent suppression of palmitate flux compared with nondiabetic subjects. Lipolysis was found to be very sensitive to insulin in nondiabetic humans, with half-maximal suppression occurring at plasma free-insulin concentrations of approximately 12 pM (less than 2 microU/ml). We conclude that adipose tissue lipolysis is normally exquisitely sensitive to insulin and that sensitivity, but not responsiveness to insulin, is impaired in poorly controlled IDDM.

Adult↗
PubMed1989

[Induced hypoglycemia. A unusual case of child battering].

We describe a case of Munchausen's syndrome by proxy in a 12 years old child. The administration of glibenclamide by the mother led to severe hypoglycemias in the child, who underwent various instrumental researches and a subtotal pancreatectomy before the final diagnosis could be reached. The diagnosis also was possible with the substantial help of an accurate psychological survey. The case solution, with disappearance of hypoglycemias, was made possible by the removal of the maternal presence settled by the juvenile court.

Child↗
PubMed1987

Heat shock 70 gene is differentially expressed in Histoplasma capsulatum strains with different levels of thermotolerance and pathogenicity.

The response to heat shock has been examined in two strains of the dimorphic pathogenic fungus Histoplasma capsulatum, which differ considerably in thermotolerance and pathogenicity. The gene for the 70 kD heat shock protein (hsp70) was isolated using a Drosophila hsp70 gene to screen a cosmid library of the DNA from the temperature-sensitive Downs strain (low level of thermotolerance for mice). Using the cloned gene as a probe, we have measured the transcription of the endogenous hsp70 gene at 25 degrees C and in response to temperature shift to 34 degrees, 37 degrees and 40 degrees C, temperatures that trigger the mycelial to yeast phase transition in this fungus. The gene is constitutively transcribed at low levels, both in the yeast and the mycelial stages. Synthesis of hsp70 mRNA was transiently increased 1 to 3 h after the temperature shifts. By Northern analysis, peak levels of transcription were shown to occur at 34 degrees C in the Downs strain and at 37 degrees C in the more pathogenic G222B strain. Our results are consistent with reports in which it has been shown that heat shock gene expression is part of temperature adaptation and probably developmental processes. The low levels of transcription of the hsp70 gene in the Downs strain at 37 degrees C correlate with its greater temperature sensitivity and low level of virulence.

Animals↗
PubMed1987

The detection of internal mammary lymph nodal chain metastases in breast cancer using radiolabelled colloids.

The authors report their studies of 39 lymphoscintigraphies performed on patients with breast cancer. They point out that interpretation of scintigraphic imaging must take into account the morphologic variations of the lymph nodes of the internal mammary chains (i.e. single central chain, single central lymph node) and the morphological difference in the symmetry of lymph nodes considered non-pathologic to avoid false positives. The authors retain that lack of visualization of a chain, conspicuous increase in size of a lymph node, asymmetry of pathologic development, or reduced uptake by one or more lymph nodes of the internal mammary chains must be interpreted as a sign of metastatic spread. The authors recommend lymphoscintigraphy as an effective technique in the screening of breast cancer patients for staging, follow-up, restaging, and planning of radiotherapy.

Breast Neoplasms↗