A de novo mosaic mutation in SPAST with two novel alternative alleles and chromosomal copy number variant in a boy with spastic paraplegia and autism spectrum disorder.

Here we report a 12 year old male with an extreme presentation of spastic paraplegia along with autism and dysmorphisms. Whole exome sequencing identified a predicted pathogenic pair of missense variants in SPAST at the same chromosomal location, each with a different alternative allele, while a chromosome microarray identified a 1.73 Mb paternally inherited copy gain of 1q21.1q21.2 resulting in a blended phenotype of both Spastic paraplegia 4 and 1q21.1 microduplication syndrome. We believe that the extreme phenotype observed is likely caused by the presence of cells which contain only mutant SPAST, but that the viability of the patient is possible due mosaicism of mutant alleles observed in different proportions across tissues.

The complete genomes of Staphylococcus aureus bacteriophages 80 and 80α--implications for the specificity of SaPI mobilization.

Staphylococcus aureus pathogenicity islands (SaPIs) are mobile elements that are induced by a helper bacteriophage to excise and replicate and to be encapsidated in phage-like particles smaller than those of the helper, leading to high-frequency transfer. SaPI mobilization is helper phage specific; only certain SaPIs can be mobilized by a particular helper phage. Staphylococcal phage 80α can mobilize every SaPI tested thus far, including SaPI1, SaPI2 and SaPIbov1. Phage 80, on the other hand, cannot mobilize SaPI1, and ϕ11 mobilizes only SaPIbov1. In order to better understand the relationship between SaPIs and their helper phages, the genomes of phages 80 and 80α were sequenced, compared with other staphylococcal phage genomes, and analyzed for unique features that may be involved in SaPI mobilization.

Amino acid substitutions within the leucine zipper domain of the murine coronavirus spike protein cause defects in oligomerization and the ability to induce cell-to-cell fusion.

The murine coronavirus spike (S) protein contains a leucine zipper domain which is highly conserved among coronaviruses. To assess the role of this leucine zipper domain in S-induced cell-to-cell fusion, the six heptadic leucine and isoleucine residues were replaced with alanine by site-directed mutagenesis. The mutant S proteins were analyzed for cell-to-cell membrane fusion activity as well as for progress through the glycoprotein maturation process, including intracellular glycosylation, oligomerization, and cell surface expression. Single-alanine-substitution mutations had minimal, if any, effects on S-induced cell-to-cell fusion. Significant reduction in fusion activity was observed, however, when two of the four middle heptadic leucine or isoleucine residues were replaced with alanine. Double alanine substitutions that involved either of the two end heptadic leucine residues did not significantly affect fusion. All double-substitution mutant S proteins displayed levels of endoglycosidase H resistance and cell surface expression similar to those of the wild-type S. However, fusion-defective double-alanine-substitution mutants exhibited defects in S oligomerization. These results indicate that the leucine zipper domain plays a role in S-induced cell-to-cell fusion and that the ability of S to induce fusion may be dependent on the oligomeric structure of S.

Managed care, attitudes, and career choices of internal medicine residents.

The influence of managed care on internal medicine residents' attitudes and career choices has not yet been determined and could be substantial. In a survey of 1,390 third-year internal medicine residents, 21% believed that managed care was the best model of health care for the United States, and 31% stated they would be satisfied working in a managed care system. Those from high managed care communities (>30% penetration) were only slightly more accepting of managed care, but were more likely to choose general internal medicine as a career (54%, p = .0009) than those from communities with lower managed care penetration.

The development of the Starr-Edwards heart valve.

Development of the Starr-Edwards heart valve marked a new era in the treatment of valvular heart disease. Until the development of the Starr-Edwards valve, there were no published reports of patients who had lived longer than 3 months with a prosthetic valve in the mitral position. This valve was the result of a unique partnership between a young surgeon, Dr. Albert Starr, and an experienced engineer, Mr. Lowell Edwards. Working as a team, these 2 men developed and successfully implanted the 1st Starr-Edwards valve within less than 2 years of their 1st meeting. Their key to success was their willingness and ability to make repeated modifications to their design to solve each clinical problem as it arose. Their constant focus on the clinical goal aided the rapid transformation of their design from a leaflet valve to a shielded ball valve, and finally to an unshielded ball valve suitable for implantation in a human being. Along the way, they abandoned the idea of imitating the appearance of native valves, in favor of developing valves that would be clinically successful. Their work has provided help and hope for patients who otherwise would have died from the complications of rheumatic heart disease and other valvular disorders for which valve replacement is the only treatment.

Comparison of covalent binding of acetaminophen and the regioisomer 3'-hydroxyacetanilide to mouse liver protein.

The hepatotoxicity of the analgesic acetaminophen has been previously attributed to metabolic activation by cytochrome P450 to the reactive intermediate N-acetyl-p-benzoquinone imine. At therapeutic doses this species is detoxified by reaction with glutathione; however, following a hepatotoxic dose, liver glutathione levels are depleted and the metabolite covalently binds primarily to cysteine groups on proteins as 3-(cystein-S-yl)acetaminophen adducts. Altered function of critical proteins has been postulated to be the mechanism of hepatotoxicity. Covalent binding has been studied by both radiochemical methods and immunochemical methods. Utilizing Western blot analysis with an antiserum which recognizes acetaminophen we have previously shown that covalent binding occurs on a number of proteins in various hepatic fractions. In an effort to better understand the role of covalent binding in the toxicity, others have studied the non-hepatotoxic isomer 3'-hydroxyacetanilide. Administration of large doses of radiolabeled acetaminophen or 3'-hydroxyacetanilide resulted in similar levels of covalent binding to proteins. To better understand the role of covalent binding in toxicity we have administered mice 3'-hydroxyacetanilide and acetaminophen, and analyzed liver fractions for protein adducts using anti-3-(cystein-S-yl)acetaminophen and anti-arylacetamide antisera in Western blot assays. Analysis of liver fractions from acetaminophen-treated mice, with both antisera showed, as has been previously reported, that acetaminophen covalently binds to a number of hepatic proteins. In liver from 3'-hydroxyacetanilide-treated mice, covalent adducts were detected with an anti-arylacetamide antiserum only. A major 3'-hydroxyacetanilide protein adduct was observed in microsomes at 50 kDa. Minor adducts were observed at 47 kDa in microsomes and 56 kDa in cytosol. 3'-Hydroxyacetanilide protein adducts were not observed in the 10,000 x g pellet. Densitometric analysis of a time course of 3'-hydroxyacetanilide protein adducts indicated that peak levels of the 50 kDa microsomal protein adduct occurred at 1 h and subsequently decreased.

Acetaminophen-induced hepatotoxicity. Analysis of total covalent binding vs. specific binding to cysteine.

Acetaminophen-induced hepatotoxicity is believed to be mediated by covalent binding of the reactive metabolite N-acetyl-p-benzoquinone imine to essential proteins in liver. It has been shown that the primary reaction of this metabolite with hepatic proteins is the formation of 3-(cysteine-S-yl)-acetaminophen adducts. The importance of covalent binding to other amino acids that may be formed by reaction of N-acetyl-p-benzoquinone imine with protein is unclear. Previously, we developed immunochemical assays for the acetaminophen cysteine adducts by immunizing animals with the conjugate 3-(N-acetylcystein-S-yl)acetaminophen-keyhole limpet hemocyanin, wherein the carboxyl group of the N-acetyl-cysteine moiety was coupled to amino groups on the protein. A very sensitive and specific immunochemical assay was developed for acetaminophen specifically bound to cysteine groups on protein [3-(cystein-S-yl)acetaminophen protein adducts]. Analysis of protein adducts indicated that after toxic doses, acetaminophen covalently bound at high levels to cysteine residues on a relatively small number of hepatic proteins. In the present work, a new antiacetaminophen antiserum was prepared by immunizing mice with 4-acetamidobenzoic acid coupled to keyhole limpet hemocyanin. Competitive ELISA data indicate that the resulting antiserum has excellent recognition of acetaminophen and related arylacetamide derivatives. Using this new antiserum, Western blot analyses of liver proteins from acetaminophen-intoxicated mouse livers were performed and compared with similar assays using the anti-3-(cystein-S-yl)acetaminophen antiserum. Visual and densitometric analyses of the Western blots indicate that the two antisera detect the same primary acetaminophen protein adducts; however, minor differences in the intensity of certain bands were observed. These differences may represent either differences in antibody accessibility to 3-(cystein-S-yl)acetaminophen adducts or differences in the proportion of acetaminophen bound to cysteine vs. binding to other amino acids.

Substance-impaired physicians probationary and voluntary treatment programs compared.

We compared the characteristics and treatment outcomes of substance-impaired physicians monitored by two different programs in Oregon: a probationary program administered by the Oregon Board of Medical Examiners and the confidential, voluntary Diversion Program for Health Professionals. Demographic, substance use, and treatment outcome variables were obtained by a retrospective medical record review from 41 physicians monitored by the Oregon board and 56 physicians monitored by the diversion program during a 3-year study period. Compared with physicians monitored by the Oregon board, physicians in the diversion program were younger, more likely to be in training programs and less likely to be in hospital-based practice settings, more often reported by immediate rather than third-party contacts, more likely to choose in-state inpatient treatment than out-of-state treatment, and less likely to have concurrent mental illness diagnoses (P < .05 for all comparisons). Short-term relapse rates did not differ statistically between the groups (22.0% for the Oregon board group, 14.3% for the diversion program group). The higher number of younger physicians and physicians in training and tendency toward increased reporting by immediate contacts in the diversion program suggested earlier intervention than in the Oregon board group.

Suppression of tumorigenicity mediated by 5-azacytidine and associated with increased chromosome number.

5-Azacytidine (5-azaC), a hypomethylating agent, was examined for the effect on a highly tumorigenic murine cell line, T984-15. While 20 of 20 untreated subclones of T984-15 produced tumors when injected into BALB/c nude mice, 14 of 15 T984-15 subclones that were treated for 24 hours with 5 micrograms 5-azaC/ml displayed suppressed tumorigenesis under identical conditions. Of the 14 clones that were suppressed, 12 were nontumorigenic and 2 showed a greatly increased latency. Chromosome analyses of 5-azaC-treated nontumorigenic clones revealed that, in contrast to untreated tumorigenic controls (median chromosome number 49-59), 9 of 10 5-azaC-treated nontumorigenic clones analyzed displayed an elevated chromosome complement (68-94 chromosomes/cell). The increase in chromosome number occurred progressively with time, following a single 24-hour 5-azaC treatment, indicating that 5-azaC was not selecting for a subpopulation of cells with an elevated chromosome complement. The evidence that the hypomethylating agent 5-azaC can suppress a cell's tumorigenic potential and that this suppression correlates with increased chromosome number suggests that 5-azaC modulates cellular phenotypes by mechanisms that involve alterations in a cell's chromosome complement.

The use of support services by care providers of the aged.

Provision of home care support services is currently propounded as a means of facilitating family care of the dependent aged. In this study, interviews were carried out with forty two providers of care and accommodation for an elderly relative. The data indicate that those careproviders who were extensive users of formal support services were also likely to express the need for still more help with their careproviding task. Although increased cost, level of co-operation from the elderly relative, and reluctance to introduce change into the routine of these dependants were cited as reasons for not satisfying the need for help, it is plausible that mutual dependency between the careproviders and the elderly relative also influenced service use. Recognition and acknowledgement of such a relationship has implications for the planning and delivery of home care support services.

Social support in normal aging.

The role of social support in helping elderly people deal with stressful life events is quite complex. This complexity exists because it is difficult to define exactly what social support is, and because the experiences of `normal' aging vary. This article uses the example of adaptation to widowhood to examine the relationship between normal aging and sources, types, and patterns of social support. These factors influence the extent to which support lessens the impact of age-related stressful events. The physician has a role in primary social support, and also in facilitating the supportive functions of family and others.

Thyroid uptake of 131-I following kippuran renal scintillation camera studies in children.

The thyroid uptake of radioactive iodine after scintillation camera studies using -131I-labeled hippuran was studied and the radiation dose calculated in 30 euthyroid children with normal renal function. Fifteen children received Lugol's solution which reduced the thyroid uptake and radiation dose significantly.