Acute bilateral striatal necrosis in an infant: CT and MRI

We report a case of acute bilateral striatal necrosis in an infant. CT and MRI findings are described.     

In vivo surface analysis of titanium and stainless steel miniplates and screws

OBJECTIVE: To determine the results peranal excision for rectal carcinoma. DESIGN: Retrospective case series. SETTING: A university-affiliated hospital. PATIENTS: Of 178 patients who presented for curative resection of rectal carcinoma between 1975 and 1993, 19 (10.7%) were deemed suitable for local excision. There were 10 men and 9 women with a mean age of 71.2 years. The follow-up ranged from 13 to 184 months. INTERVENTION: Peranal excision. MAIN OUTCOME MEASURES: Histologic differentiation, gross morphology, depth of invasion and size of the carcinoma, adequacy of margins of excision, complications of operation, rates of recurrence, results of salvage therapy and 5-year survival. RESULTS: There were no intraoperative complications. Postoperative complications included urinary retention (one patient) and bleeding (one patient). There were five local recurrences (26%). Salvage operations were performed in three (60%) patients and were successful in two of them. The 5-year cancer-specific survival rate was 82%. The recurrence rate was higher in patients with inadequate margins of excision and ulcerative lesions. Neither size nor grade of the carcinoma correlated with recurrence. CONCLUSIONS: Local excision of rectal carcinoma can be performed successfully in selected patients. Diligent follow-up is required, because up to 60% of local recurrences can be treated successfully.     

Muscle mass and fat mass in relation to bone mineral density in very old men and women: the Framingham Heart Study

Aim of the study was investigate the cross-sectional relationship between body composition and bone mineral density (BMD) in very old men and women. The study sample consisted of 504 women and 285 men, aged 72-93 yr, participating in examination 22 (1992-1993) of the Framingham Heart Study. Total body BMD, regional BMD, and soft-tissue body composition was measured by dual-energy X-ray absorptiometry. Both muscle mass and percentage body fat were positively associated with total body BMD in women. After adjustment for age, physical activity, smoking status, estrogen use, and thiazide use, BMD increased with increasing tertile of muscle mass (p = 0.007) and with increasing tertile of percentage body fat (p = 0.0001) in women. In men muscle mass, not percentage body fat, was positively associated with BMD. After adjustment for potential confounders, BMD remained associated with muscle mass only (p = 0.02). These results were similar for leg BMD and arm BMD. The study suggests that the influence of muscle and fat mass on bone mineral density is different between very old men and women.     

Expression of a functional anaphylatoxin C3a receptor by astrocytes

Human astrocyte cell lines reportedly contain a specific receptor for the complement anaphylatoxin C3a based on ligand-binding studies, functional responses, and RNA analysis by RT-PCR. Uptake of 125I-C3a by astrocytes was specific and reversible. Scatchard analysis indicated the presence of two classes of binding sites. High-affinity binding sites were abundantly expressed (20,000-80,000 sites per cell) with an estimated K(D) of 1-2 nM. Low-affinity binding sites with a K(D) of 209 nM were largely expressed (n > or = 4 x 10(6) sites per cell) and probably did not reflect a receptor-mediated binding, but rather an ionic interaction between C3a and the membrane. Analysis of astrocyte mRNA by RT-PCR with three different sets of primers covering 60% of the C3a receptor (C3aR) mRNA sequence indicated that glial C3aR was identical to the leukocytic one. Western blot analysis using a specific anti-C3aR evidenced a C3aR with a molecular mass of 60,000 Da. C3a and a superagonist peptide, E7, induced a transient increase of intracellular [Ca2+] in primary culture of astrocytes. Treatment of the ligands by carboxypeptidase B to eliminate the C-terminus Arg considerably decreased the [Ca2+] response. Moreover, flow cytometry experiments demonstrated the expression of C3aR on normal rat astrocyte membrane. This report brings new insight for the role of the complement system in the brain inflammation response.     

How accurate is male recall of reproductive information?

The purpose of this study was to determine how well men recall reproductive information. By using a questionnaire, the authors surveyed men who had undergone orchiopexy for undescended testes and a group of matched control men, all of whom had had surgery at the Children's Hospital of Pittsburgh in Pittsburgh, Pennsylvania (n = 77), and their spouses. Subjects were a random subset of a larger (n = 1,212) male fertility study, which has been ongoing since 1992. In 1994, the spouses of men who participated in the study completed a short telephone survey that contained questions previously asked of their partners. Pearson correlations and kappa statistics were calculated to evaluate the accuracy of male recall of reproductive information. For the continuous measures, such as time to conception and frequency of intercourse, the correlations were high to moderate (r = 0.84 (p < 0.001) and r = 0.45 (p < 0.001), respectively). Agreement between the men and their spouses on the majority of bivariate (yes/no) questions, such as those concerning the use of birth control, as measured by the kappa statistic, was moderate to very good (K ranged from 0.14 to 0.69). Statistics were similar for formerly cryptorchid and control men. Male participants' responses to questions about their reproductive histories were accurate as compared with the responses given by their spouses. In this sample from a large cohort study, men appeared to recall reproductive information with acceptable accuracy.     

Redox properties of human medium-chain acyl-CoA dehydrogenase, modulation by charged active-site amino acid residues

The modulation of the electron-transfer properties of human medium-chain acyl-CoA dehydrogenase (hwtMCADH) has been studied using wild-type and site-directed mutants by determining their midpoint potentials at various pH values and estimating the involved pKs. The mutants used were E376D, in which the negative charge is retained; E376Q, in which one negative charge (pKa approximately 6. 0) is removed from the active center; E99G, in which a different negative charge (pKa approximately 7.3) also is affected; and E376H (pKa approximately 9.3) in which a positive charge is present. Em for hwtMCADH at pH 7.6 is -0.114 V. Results for the site-directed mutants indicate that loss of a negative charge in the active site causes a +0.033 V potential shift. This is consistent with the assumption that electrostatic interactions (as in the case of flavodoxins) and specific charges are important in the modulation of the electron-transfer properties of this class of dehydrogenases. Specifically, these charge interactions appear to correlate with the positive Em shift observed upon binding of substrate/product couple to MCADH [Lenn, N. D., Stankovich, M. T., and Liu, H. (1990) Biochemistry 29, 3709-3715], which coincides with a pK increase of Glu376-COOH from approximately 6 to 8-9 [Rudik, I., Ghisla, S., and Thorpe, C. (1998) Biochemistry 37, 8437-8445]. From the pH dependence of the midpoint potentials of hwtMCADH two mechanistically important ionizations are estimated. The pKa value of approximately 6.0 is assigned to the catalytic base, Glu376-COOH, in the oxidized enzyme based on comparison with the pH behavior of the E376H mutant, it thus coincides with the pK value recently estimated [Vock, P., Engst, S., Eder, M., and Ghisla, S. (1998) Biochemistry 37, 1848-1860]. The pKa of approximately 7.1 is assigned to Glu376-COOH in reduced hwtMCADH. Comparable values for these pKas for Glu376-COOH in pig kidney MCADH are pKox = 6.5 and pKred = 7.9. The Em measured for K304E-MCADH (a major mutant resulting in a deficiency syndrome) is essentially identical to that of hwtMCADH, indicating that the disordered enzyme has an intact active site.     

Complete physical map of the common deletion region in Williams syndrome and identification and characterization of three novel genes

Williams syndrome (WS) is a contiguous gene deletion disorder caused by haploinsufficiency of genes at 7q11.23. We have shown that hemizygosity of elastin is responsible for one feature of WS, supravalvular aortic stenosis (SVAS). We have also implicated LIM-kinase 1 hemizygosity as a contributing factor to impaired visual-spatial constructive cognition in WS. However, the common WS deletion region has not been completely characterized, and genes for additional features of WS, including mental retardation, infantile hypercalcemia, and unique personality profile, are yet to be discovered. Here, we present a physical map encompassing 1.5 Mb DNA that is commonly deleted in individuals with WS. Fluorescence in situ hybridization analysis of 200 WS individuals shows that WS individuals have the consistent deletion interval. In addition, we identify three novel genes from the common deletion region: WS-betaTRP, WS-bHLH, and BCL7B. WS-betaTRP has four putative beta-transducin (WD40) repeats, and WS-bHLH is a novel basic helix-loop-helix leucine zipper (bHLHZip) gene. BCL7B belongs to a novel family of highly conserved genes. We describe the expression profile and genomic structure for each of these genes. Hemizygous deletion of one or more of these genes may contribute to developmental defects in WS.     

RP-HPLC binding domains of proteins

Procedures have been developed to identify the chromatographic binding domains of horse heart cytochrome c (Cyt c) and bovine growth hormone (bGH) during their interaction with reversed-phase sorbent materials. The procedure involves adsorption of the protein solute to the chromatographic sorbent, followed by proteolytic cleavage. Comparison of the proteolytic map obtained for Cyt c and bGH in free solution with the corresponding map obtained when these proteins are adsorbed to the chromatographic sorbent revealed significant differences in the digestion pattern. Following characterization of the peptides generated in both maps, the results indicated that specific regions on the surface of both Cyt c and bGH are inaccessible to tryptic cleavage when adsorbed to the hydrophobic surface of both a C-4 and a C-18 sorbent. Based on the assumption that the region of the protein surface that is in contact with the sorbent remains intact and bound to the sorbent during the digestion step, while the protein surface that is exposed to the solvent is accessible to proteolysis, the regions that were inaccessible to tryptic digestion were found to correspond to hydrophobic domains on the protein surface. These results also suggest that the three-dimensional structures of these proteins remain largely intact upon adsorption to the hydrophobic surface.     

Dual role of dendritic cells in the induction and down-regulation of antigen-specific cutaneous inflammation

We have previously reported that contact sensitivity (CS) to dinitrofluorobenzene (DNFB) in C57BL/6 mice was mediated by MHC class I-restricted CD8+ T cells and down-regulated by MHC class II-restricted CD4+ T cells. In this study, we analyzed the contribution of dendritic cells (DC) in the induction of these two T cell subsets endowed with opposite functions. Hapten-pulsed skin- and bone marrow-derived DC, obtained from either normal C57BL/6 mice or from MHC class II (I+ II-) and MHC class I (I- II+)-deficient mice, were tested for their ability to prime normal mice for CS to dinitrofluorobenzene. Expression of MHC class I molecules by transferred DC was mandatory both for the induction of CS and for the generation of hapten-specific CD8+ T cells in lymphoid organs. I+ II- DC were as potent as I+ II+ DC in priming for CS, demonstrating that activation of effector CD8+ T cells can occur independently of CD4+ T cell help. I- II+ DC could not immunize for CS, although they could sensitize for a delayed-type hypersensitivity reaction to protein Ags. Moreover, I- II+ DC injected simultaneously with cutaneous sensitization down-regulated the inflammatory response, suggesting that hapten presentation by MHC class II molecules could prime regulatory CD4+ T cells. These results indicate that DC can present haptenated peptides by both MHC class I and class II molecules and activate Ag-specific CD8+ effector and CD4+ regulatory T cell subsets, concurrently and independently.     

Enhancement of adenovirus-mediated gene transfer to human bone marrow cells

Adenovirus infection of CD34+ hematopoietic stem/progenitor cells is dependent on the multiplicity of infection (MOI), time of incubation, the volume in which the co-incubation occurs and the presence or absence of growth factors. Studies revealed that a brief co-incubation (1-8 hours), resulted in low levels of transgene expression, suggesting that adenovirus infection of CD34+ cells occurs slowly, and optimal transduction requires a 24 hour exposure to adenovirus. Infection by Ad/beta-gal or Ad/p53 at a MOI of 500:1 provided a high transduction efficiency but inhibited hematopoietic function. However, treatment at a MOI of 50-100 resulted in efficient transduction (10.7-15.7% positive) without detectable toxicity. Secondary proof of adenovirus transgene expression was demonstrated by detection of mRNA for p53 in Ad/p53 infected stem cells. We conclude that a 24 hour exposure to recombinant adenovirus encoding p53 or beta-gal, at a MOI of 50-100 is optimal for in vitro gene transfer to BM cells and has no significant effect on hematopoietic function. Adenovirus-mediated transduction of BM cells can also be modulated by growth factors (IL-3, GM-CSF and G-CSF) with improved gene delivery and maintenance of hematopoietic function. In summary, adenovirus vectors can be used to transiently transduce stem cells, and conditions have been defined to maximize expression and limit inhibitory effects on CD34+ cells. These data support continued investigation of this vector for local cytokine delivery and purging of stem cell products.