The effects of dopaminergic D2 stimulation and blockade on smoking behavior

Researchers have hypothesized that dopamine mediates the reinforcing effects of stimulant drugs, including nicotine. Three experiments tested whether manipulating dopamine would alter human smoking behavior. Experiments used double-blind, repeated measures designs. In Experiment 1, 4 participants were given haloperidol (a dopamine antagonist; placebo, 0.5, and 1.0 mg) on 3 occasions. The smoking rate was faster in the 1.0 mg versus the placebo condition. In Experiment 2, 12 participants were given haloperidol (2.0 mg) and placebo on 2 occasions. The intercigarette interval was shorter at the expected time of peak drug concentration. In Experiment 3, 5 participants were given bromocriptine (a dopamine agonist, 2.5 mg) and placebo on 2 occasions. The smoking rate was significantly slower with bromocriptine. These results suggest that blockade of D2 receptors increases smoking whereas their stimulation decreases smoking.     

Self-esteem in children medically managed for attention deficit disorder

Self-esteem was measured initially in a group of 21 eight- to 12-year-old children with newly diagnosed attention deficit disorder/hyperactivity and remeasured after 1-month courses of treatment with methylphenidate and placebo given in double-blind crossover fashion. Multimodal management of all patients included diagnosis, demystification, medication, close follow-up with supportive counseling, and referral as indicated for psychosocial and educational assistance. Long-term follow-up of 12 children who continued to receive methylphenidate was done for an average of 16 months. Initial total self-esteem was low in 30% of all subjects, intermediate in 55%, and high in 15%. No statistically significant changes occurred in self-esteem during the short-term phase of the study despite clinically significant behavioral responses to medication as assessed by serial questionnaires. At long-term follow-up, total, general, and academic self-esteem scores were improved significantly, however. These findings indicate that many preadolescents with attention deficit disorder/hyperactivity exhibit low self-esteem. Despite clinical response to medication, short-term improvement in self-esteem may not occur; however, long-term, multimodal management that includes medication does appear to improve self-esteem.     

Gene targeting in mouse embryonic stem cells with an adenoviral vector

We examined the ability of an E1, E3-defective adenoviral vector to act as a substrate for homologous recombination with chromosomal DNA by including host chromosomal sequence from the mouse Fgr locus that also contained a selectable marker. After infection of mouse embryonic stem cells, stable integration was selected for neomycin resistance and the efficiency of homologous recombination was evaluated. The adenoviral vector was capable of infecting mouse embryonic stem cells efficiently. Between 30–50% of the input virus reached the nuclei after 24 hours of infection. Surprisingly, even without negative selection, 25–40% of the integration resulted from homologous recombination at m.o.i. 10 and 100, although the absolute efficiency of integration was low. Our results suggest that it is possible to modify the structure of an adenoviral vector to achieve a high gene targeting efficiency, resulting in regulated and long-term expression of an introduced gene.     

A new family with fra(10)(q25): spontaneous expression and 100% expression with 100 microM BrdU

We report on a family with fra(10)(q25) ascertained through a female with multiple minor anomalies and present in her phenotypically normal father and other family members. The site is expressed spontaneously at levels of 9% in lymphocytes, 2% in lymphoblasts, and 6% in skin fibroblasts. Expression frequency is significantly enhanced to levels as high as 100% by addition of BrdU to the culture medium. The consistently high level of induced expression in lymphoblasts from the proband facilitates analysis of the biochemical and structural bases of fragile site expression.     

Overexpression of focal adhesion kinase in primary colorectal carcinomas and colorectal liver metastases: immunohistochemistry and real-time PCR analyses.

PURPOSE: Focal adhesion kinase (FAK), a protein tyrosine kinase that functions in signaling events between cells and their extracellular matrix, is overexpressed in a variety of human solid tumors. To determine whether FAK expression is up-regulated in colorectal cancer, we analyzed FAK mRNA and protein levels in primary colorectal tumors and colorectal liver metastases. EXPERIMENTAL DESIGN: p125(FAK) expression in formalin-fixed paraffin-embedded (FFPE) tissue was studied using immunohistochemical assays on 24 matched primary colorectal carcinomas and colorectal liver metastases as well as 18 different colorectal liver metastases using monoclonal anti-FAK 4.47. FAK mRNA expression was quantitated by real-time PCR on 39 matched normal colorectal mucosa and primary colorectal carcinomas as well as on 17 separate liver metastases. RESULTS: Elevated levels of p125(FAK) expression were demonstrated in both primary colorectal tumors and colorectal liver metastases compared with normal colorectal mucosa. Immunohistochemistry experiments demonstrated equivalent FAK expression in matched samples of colorectal primary tumors and liver metastases. Using real-time PCR in 39 matched samples, FAK mRNA copy number was significantly higher in primary colorectal tumors compared with normal colorectal mucosa. FAK expression was analyzed by both real-time PCR and immunohistochemistry in a separate set of colorectal liver metastases. Immunohistochemistry demonstrated high levels of FAK expression in 89% of samples. Furthermore, FAK mRNA copies in these unmatched liver metastases were significantly higher than the primary tumor FAK mRNA copies. CONCLUSION: These experiments have shown that both primary colorectal cancers and colorectal liver metastases express high levels of FAK mRNA and p125(FAK) protein. Furthermore, the majority of colorectal liver metastases demonstrated robust FAK expression equivalent to or greater than that in the primary colorectal tumor.     

Three-dimensional US of the prostate: early experience.

PURPOSE: To assess the feasibility of using a three-dimensional (3D) endorectal transducer at ultrasonography (US) in the prostate gland in a clinical setting. MATERIALS AND METHODS: Sixteen patients underwent 3D imaging of the prostate gland with a 3D endorectal probe following conventional two-dimensional (2D) US and prior to prostatic biopsy. Image acquisition was performed as a volume of data with nearly immediate reconstruction and simultaneous display of sectional anatomy in three orthogonal planes--sagittal plane, transverse or coronal plane, or any arbitrary oblique plane. Images were evaluated for presence of focal lesions, glandular volume, visualization of lateral and anterior portions of the gland, and extraglandular extension of tumor. RESULTS: Three-dimensional US allowed better visualization of the gland and focal lesions, especially on the coronally reconstructed images, which were judged superior to the sagittally or transversely reconstructed images for interpretation in 50% of the patients. Prostatic volumes obtained from 3D US were consistently smaller than volumes obtained from 2D US (20% difference, P = .006). Three-dimensional US was superior to 2D US in depicting tumor presence (nine of 10 right hemispheres, three of eight left hemispheres) and extraglandular extent of disease (three of five hemispheres). CONCLUSION: Three-dimensional endorectal prostatic US appears to be clinically feasible and easy to perform. Added anatomic information from the coronal plane may allow better depiction of tumors and extraglandular spread than is possible with current 2D techniques.     

A repertoire of monoclonal antibodies with human heavy chains from transgenic mice.

The introduction of human immunoglobulin gene segments in their unrearranged configuration into the germ line of mice might allow the production of a repertoire of human antibodies. Such transgenic mice could be used for the production of human monoclonal antibodies against human antigens. To test the feasibility of this approach, mice were created that carry a human heavy-chain minilocus comprising unrearranged immunoglobulin variable, diversity, and joining elements linked to a human mu-chain gene. The gene segments of this minilocus are rearranged in a large proportion of cells in thymus and spleen but not in nonlymphoid tissue. Some 4% of the B lymphocytes synthesize human mu chains resulting in a serum titer of about 50 micrograms of transgenic IgM antibody per ml. Hybridomas were established from the transgenic mice that stably secreted several micrograms of antibodies containing human mu heavy chains per milliliter.     

Mucolipidosis II: unusual presentation with a congenital angulated fracture

A newborn infant who was subsequently shown to have mucolipidosis II was noted to have a congenital angulated fracture. The appearance of the fracture led to an original clinical impression of osteogenesis imperfecta. Although pathologic fractures are frequently evident by roentgenographic examination, to our knowledge this is the first report of a congenital angulated fracture in a patient with mucolipidosis II.