Transient gene expression from yeast artificial chromosome DNA in mammalian cells is enhanced by adenovirus

The introduction of high molecular weight DNA into mammalian cells is useful for gene expression studies. However, current transfection strategies are inefficient, necessitating propagation of stable DNA transformants prior to analysis of gene expression. Here we demonstrate that transient lipid-mediated DNA transfection can be used to assess gene expression from yeast artificial chromosomes (YACs) containing the 230 kb cystic fibrosis transmembrane conductance regulator gene ( CFTR ) and Escherichia coli lacZ . We also show that psoralen-UV inactivated adenovirus significantly enhances transfection efficiency. The ability to deliver high molecular weight DNA using lipid-mediated transfection should expedite the analysis of large human genes contained within artificial chromosome vectors.     

Solitary pancreas allografts. The role of percutaneous biopsy and standardized histologic grading of rejection

Murine models such as NZB/W F1, NZB.H-2bm12 and MRL.lpr/lpr mice have provided greater insight into the pathogenic mechanisms of lupus. To understand further the roles of T cells and cytokines in the pathogenesis of murine lupus, 11 cloned anti-DNA antibodies augmenting autoreactive T cell lines were derived from NZB/W F1 mice. All these autoreactive cells responded to syngeneic splenic cells and helped syngeneic B cells to produce anti-DNA antibodies, especially the IgG antibody. Ten out of 11 autoreactive T cell lines expressed neither CD4 nor CD8 cell surface markers on their surface. In addition, the cytokine production pattern of these autoreactive T cell lines was predominantly of type 0 (Th0) or type 2 T helper cells (Th2). To further investigate the role of accessory molecules in the activation of these autoreactive T cell lines, expression of IL-2R and heat-stable antigen (HSA) on these autoreactive T cells was analysed. Results suggest that the HSA played a critical role in the activation and function of these double-negative cloned autoreactive T cells.     

Video game-related seizures: a report on 10 patients and a review of the literature

OBJECTIVE: To further describe the features, postulated pathophysiology, treatment, and outcome of seizures occurring while playing or watching video games (video game-related seizures (VGRS)). DESIGN: We evaluated retrospectively 10 patients with VGRS seen by us and reviewed 25 reported cases. RESULTS: The 35 patients ranged in age from 1 to 36 years (mean: 13.2); and 26 subjects (74%) were male. Eight individuals (29%) had prior infrequent nonfebrile seizures, 4 (11%) had febrile convulsions, and 2 (6%) had a family history of epilepsy. VGRS consisted of generalized tonic-clonic seizures in 22 of 35 individuals (63%); absences in 2 (6%); simple partial seizures in 6 (19%); complex partial seizures in 4 (11%); and other manifestations in 4. Neurologic examination and computed tomographic and magnetic resonance imaging scans were normal. Electroencephalograms demonstrated generalized or focal, interictal or ictal epileptic patterns in 11 of 21 patients (52%) and photoparoxysmal responses in 17 of 32 (53%). Eleven of 15 individuals (73%) treated with video game (VG) abstinence alone, 3 of 6 who received anticonvulsants but played VGs, and 7 of 12 treated with combined VG abstinence and anticonvulsants had no further seizures. CONCLUSIONS: We postulate that a special convulsive susceptibility of selected neurons in striate, peristriate, infratemporal, and posterior parietal cortices to particular visual stimuli plays a major role in VGRS. VG abstinence is the treatment of choice of VGRS. Anticonvulsant medication is suggested only for those individuals who continue to play VGs or suffer from seizures triggered by other, unavoidable visual stimuli, or from unprovoked attacks.     

Declining seroprevalence in a very large HIV epidemic: injecting drug users in New York City, 1991 to 1996

OBJECTIVES: This study assessed recent trends in HIV seroprevalence among injecting drug users in New York City. METHODS: We analyzed temporal trends in HIV seroprevalence from 1991 through 1996 in 5 studies of injecting drug users recruited from a detoxification program, a methadone maintenance program, research storefronts in the Lower East Side and Harlem areas, and a citywide network of sexually transmitted disease clinics. A total of 11,334 serum samples were tested. RESULTS: From 1991 through 1996, HIV seroprevalence declined substantially among subjects in all 5 studies: from 53% to 36% in the detoxification program, from 45% to 29% in the methadone program, from 44% to 22% at the Lower East Side storefront, from 48% to 21% at the Harlem storefront, and from 30% to 21% in the sexually transmitted disease clinics (all P < .002 by chi 2 tests for trend). CONCLUSIONS: The reductions in HIV seroprevalence seen among injecting drug users in New York City from 1991 through 1996 indicate a new phase in this large HIV epidemic. Potential explanatory factors include the loss of HIV-seropositive individuals through disability and death and lower rates of risk behavior leading to low HIV incidence.     

Interacting boson approximation studies of the negative parity states of 172-180Os isotopes

Semen was collected for 4 consecutive d individually from experimental broiler breeder males that had not been massaged for 7 d. The semen was mixed and diluted with the Beltsville Poultry Semen Extender with dimethylsulfoxide (DMSO) as cryoprotectant and cryopreserved. After thawing of the semen, hens were inseminated and fertility over 1 wk after a single insemination with the cryopreserved semen was determined. The overall fertility rate in this experiment (83 to 93%) was high, compared with the generally reported fertility rate of frozen-thawed fowl semen. The fertility rate of the semen collected on Days 3 and 4 was significantly higher than that of semen collected on Day 1 or 2, indicating that frequent collection over the 4-d period enhances the fertility rate of the semen.     

Extracranial distal aneurysm of posterior inferior cerebellar artery

Identification and sequencing of the obese mouse (ob) gene and its product-leptin opened an important new avenues in obesity research. This survey presents current knowledge on leptin physiology as well as the role of this protein in pathogenesis of obesity.