Function changes in spinal muscular atrophy II and III. The DCN/SMA Group

The course of spinal muscular atrophy (SMA) is not well established except for those patients whose age of onset is before 6 months and who achieve only "sit with support" as their maximum function (Werdnig-Hoffmann disease or SMA I). This study shows that there is another group of SMA patients whose age of onset and maximum function achieved can be used as prognostic guides. Fifty percent of SMA patients who could walk without assistance and whose onset was prior to age 2 years lost the ability to walk independently by age 12. Fifty percent of SMA patients who walked and whose onset was between 2 and 6 years of age lost walking ability by age 44 years. Fifty percent of SMA patients who could walk with assistance as their best function ever achieved lost this ability by age 7 years, unrelated to age of onset; none could walk with assistance after age 14 years. Seventy-five percent of SMA patients who developed the ability to sit independently as their best function were still sitting after age 7 years independent of age of onset; 50% of this group could sit independently after age 14 years. Eighty-five percent of SMA patients who could walk could not negotiate stairs without holding onto a rail. They could raise their hands above the head; however, as they lost walking ability, they lost this function as well. Only one SMA patient whose maximum function was sitting independently could get to the sitting position on his own. Only two of these patients could hold their hands above their heads. All patients with SMA lose function over time. This function loss occurs slowly and is related primarily to maximum function achieved; knowledge of age of onset provides helpful information, especially for predicting the loss of independent walking.     

Characterization of HEp-2 cell projection formation induced by diffusely adherent Escherichia coli

Diffusely adherent Escherichia coli (DAEC) are diarrheagenic E. coli whose pathogenetic mechanisms are largely unknown. DAEC have been shown to induce an unusual phenotype upon adherence to HEp-2 cells in culture characterized by the induction of long thin membrane processes extending from the cell surface. In addition, DAEC have been shown to be protected from the bactericidal effects of gentamicin when incubated with HEp-2 cells. In our studies, we found that three DAEC strains induced formation of eukaryotic cell processes and were protected from gentamicin killing after a 3 h incubation. Preincubation of HEp-2 cells with colchicine or cytochalasin D prior to infection with DAEC strain C1845 resulted in decreased projection formation, suggesting that the effect was dependent upon microfilament and microtubule rearrangement. When the standard gentamicin protection assay was extended for an additional 3 h incubation in the presence of gentamicin, a greater number of DAEC survived gentamicin treatment, more eukaryotic projections were seen in association with the bacteria and the bacteria were actually observed to be "embedded' within these projections. Projection formation was not observed when the bacteria were separated from the cells by a permeable membrane or when the inoculum was inactivated by ultraviolet irradiation. Transposon TnphoA mutants of C1845 were screened for decreased gentamicin protection. All three mutants which were deficient in gentamicin protection demonstrated less projection formation. Insertion mutations affecting gentamicin protection were localized to both the chromosome (two) and a plasmid (one). Eukaryotic projections are a novel interaction of DAEC with epithelial cells, may play a role of the survival of the bacteria against host defenses and may contribute to DAEC pathogenesis. The effect is dependent upon epithelial cell contact and requires multiple bacterial genes.     

Household robots look and learn: environment modeling and localization from an omnidirectional vision system

The work illustrates that a catadioptric omnidirectional vision system can be successfully applied for basic mobile robot navigation tasks, such as localization and environment learning. In combination with other capabilities of such a sensor, such as the recognition and tracking of humans, and because the price of such systems can be made low, this system is particularly suited for systems that are expected to operate in offices and homes in the near future, such as robotic servant systems, entertainment robots, and help for the elderly and disabled.     

Substitution of tyrosine for phenylalanine in fibrinopeptide A results in preferential thrombin cleavage of fibrinopeptide B from fibrinogen

Phenylalanine at residue 8 in the Aalpha chain of fibrinogen is a highly conserved amino acid that is believed to be critical for binding and catalysis by the serine protease thrombin. We have examined the requirement for Phe at this position by constructing a variant recombinant fibrinogen with a conservative substitution of tyrosine for phenylalanine, Aalpha F8Y fibrinogen. We found that the variant fibrinopeptide A (F8Y 1-16) was cleaved by thrombin, in contrast to the lack of cleavage of an Aalpha 1-23 peptide and an Aalpha 1-50 fusion protein with the same substitution. This result indicates that fibrinogen residues other than Aalpha 1-50 participate in thrombin binding and fibrinogen proteolysis. We found, for the first time, that thrombin-catalyzed lysis of the fibrinogen Bbeta chain preceded lysis of the Aalpha chain, such that fibrinopeptide B (FpB) was released prior to F8Y 1-16. Kinetic analysis demonstrated that F8Y 1-16 was a very poor substrate for thrombin, with a specificity constant 280-fold lower than normal fibrinopeptide A. FpB was also a poor substrate, but the specificity constant for FpB was only 4-fold lower than normal. Consequently, FpB was preferentially released from Aalpha F8Y fibrinogen. This "role reversal" had a dramatic effect on polymerization, such that the rate of Aalpha F8Y fibrinogen polymerization was 13% of the rate of normal recombinant fibrinogen. These results confirm the importance of phenylalanine at Aalpha chain residue 8 for efficient thrombin-catalyzed proteolysis of fibrinogen, and further demonstrate that sequential fibrinopeptide release has an important role in normal polymerization.     

The prevalence and severity of cancer pain: a study of newly-diagnosed cancer patients in Taiwan

In current clinical practice the "double-stapling technique" is the standard for reanastomosis following minimally invasive sigmoid resection. In the present study, we compared the TESA technique (transient endoluminally stented anastomosis) with conventional stapled anastomosis and evaluated the effect of remnant foreign material on follow-up examination with endosonography. Laparoscopic sigmoid resection was performed in 12 pigs (mean weight 63+/-5.9 kg). Animals were randomly divided into two groups: In Group A, reanastomosis was performed following a standard technique using a 29-mm circular stapler. In Group B, the TESA technique using a resorbable radiopaque stent of polyglycolic acid was applied. The anastomosis was examined by plain x-ray on days 1, 7, and 14, and by contrast enema on day 42, respectively. Endosonography, macroscopic inspection, and histological evaluation of the anastomosis were performed on day 42. All anastomoses in group A were patent. In one animal in Group B stent displacement with subsequent leak of the anastomosis was observed. Circumferential length of the anastomosis on day 42 did not differ between the groups (Group A: 8.00+/-0.45 cm vs. Group B: 7.8+/-2.0 cm, p = 0.82). The duration of the operation was 130+/-27 minutes in Group A and 100+/-18 minutes in Group B (p = 0.06). Weight gain was equal: Group A: 24+/-9.6 kg vs. Group B: 24+/-5.0 kg, p = 0.74. Endosonography on day 42 postoperatively in the area of the anastomosis in group A was impaired due to metallic staples. TESA is a competitive method for reanastomosis following laparoscopic sigmoid resection. In contrast to the conventional technique, the anastomosis is free of foreign material 1 month after the operation, which facilitates follow-up examinations with endosonography as well as other imaging diagnostics.     

A20 inhibits NF-kappaB activation in endothelial cells without sensitizing to tumor necrosis factor-mediated apoptosis

Expression of the NF-kappaB-dependent gene A20 in endothelial cells (EC) inhibits tumor necrosis factor (TNF)-mediated apoptosis in the presence of cycloheximide and acts upstream of IkappaBalpha degradation to block activation of NF-kappaB. Although inhibition of NF-kappaB by IkappaBalpha renders cells susceptible to TNF-induced apoptosis, we show that when A20 and IkappaBalpha are coexpressed, the effect of A20 predominates in that EC are rescued from TNF-mediated apoptosis. These findings place A20 in the category of "protective" genes that are induced in response to inflammatory stimuli to protect EC from unfettered activation and from undergoing apoptosis even when NF-kappaB is blocked. From a therapeutic perspective, genetic engineering of EC to express an NF-kappaB inhibitor such as A20 offers the mean of achieving an anti-inflammatory effect without sensitizing the cells to TNF-mediated apoptosis.     

In vivo perfusion measurements in the human placenta using echo planar imaging at 0.5 T

This paper alerts practitioners and administrators in correctional healthcare settings to a variety of issues of concern when advising or negotiating with state or county governments on the provision of managed behavioral healthcare. The participation of the mental health practitioner or administrator involved in determining the quality and appropriateness of behavioral managed care contractual services is an essential component of an overall healthcare service in a correctional setting. Several crucial elements are outlined relative to correctional settings, including the interface between custody and treatment providers, crisis intervention for incoming detainees or inmates, and provision of services for longer term "no parole" inmates in correctional settings. A number of considerations are reviewed, including (1) staffing, (2) drug formularies, (3) levels of service, and (4) "hidden costs," that may influence contractual negotiations as well as service provision by managed behavioral healthcare companies in correctional settings.     

Fine needle aspiration biopsy of the salivary glands. A five-year experience with emphasis on diagnostic pitfalls

OBJECTIVE: To review the fine needle aspiration (FNA) findings in 151 patients who presented with salivary gland (both major and minor) enlargement from January 1991 to December 1995 in order to determine its sensitivity and specificity and to study the various pitfalls. STUDY DESIGN: The study group consisted of 77 males and 74 females, 16-98 years old (average 55). One hundred twenty-five aspirates (83%) were from the parotid gland, 23 (15%) from the submandibular gland and 3 (2%) from the soft palate. One hundred thirty-seven cases (91%) were adequate for diagnosis. There were 89 (59%) aspirations done by cytopathologists, 100% of which were diagnostic, and 62 (41%) done by clinicians, 48 (77%) of which were diagnostic. Sixty-eight (45%) cases had histologic confirmation. There were 104 (75.9%) benign, 20 (14.6%) malignant and 13 (9.5%) atypical cytologic diagnoses. RESULTS: Using histology as the "gold standard," the sensitivity of FNA cytology was 91%, with a specificity of 96%. A number of problems were encountered in interpreting some cases, not only in differentiating benign from malignant ones but also in the specific classification of these neoplasms. Problems encountered involved differentiating hematopoietic from non-hematopoietic lesions and interpretation of spindle cell neoplasms, acinic cell carcinoma, mucoepidermoid carcinoma, adenoid cystic carcinoma, lymphoproliferative disorders, postirradiation changes, sialadenitis and atypia in pleomorphic adenoma. CONCLUSION: FNA biopsy of the salivary gland is a sensitive and specific diagnostic tool at our institution. Particular attention to subtle morphologic changes may aid in avoiding pitfalls and arriving at the right diagnosis.     

Borderline necrosis of the femoral head

To determine whether the histologic lesions classified by the system of Arlet et al as Type 2 (granular necrosis of fatty marrow) and Type 3 (complete medullary and trabecular necrosis) always progress to Type 4 (complete necrosis with marginal medullary fibrosis and appositional new bone formation), 10 femoral heads (nine patients) were monitored for 4 years using serial magnetic resonance images. These femoral heads had been diagnosed histologically as having either Type 2 (seven hips) or Type 3 (three hips) necrosis on initial core biopsies. On the initial magnetic resonance image, none of the femoral heads showed any focal lesions indicative of osteonecrosis. In all instances, superselective angiography showed interruption of the superior retinacular artery, and the bone marrow pressure was elevated. During a followup period of 48 to 54 months, no patient had a reactive low signal intensity band develop on T1 weightings, as evidence of a reparative process around the necrotic portion of the lesion, or any other findings of osteonecrosis on magnetic resonance images. These findings suggest that some Type 2 and 3 lesions of Arlet et al may not develop an obvious reactive interface of reparative revascularization and thus may not progress to definite and classic Type 4 osteonecrosis. This study supports the hypothesis that there is an ischemic threshold between reversible intraosseous hypoxia (bone marrow edema syndrome) and irreversible intraosseous anoxia (classic bone infarction or osteonecrosis) and suggests that borderline necrosis occurs in the transition zone of this ischemic threshold and is nonprogressive.     

Requirements for efficient production and transduction of human immunodeficiency virus type 1-based vectors

Phosphatidylglycerophosphate (PGP) synthase catalyzes the first step in the cardiolipin (CL) branch of phospholipid biosynthesis in mammalian cells. In this study, we isolated a Chinese hamster ovary (CHO) cDNA encoding a putative protein similar in sequence to the yeast PGS1 gene product, PGP synthase. The gene for the isolated CHO cDNA was named PGS1. Expression of the CHO PGS1 cDNA in CHO-K1 cells and production of a recombinant CHO PGS1 protein with a N-terminal extension in Escherichia coli resulted in 15-fold and 90-fold increases of PGP synthase specific activity, respectively, establishing that CHO PGS1 encodes PGP synthase. A PGP synthase-defective CHO mutant, PGS-S, isolated previously (Ohtsuka, T., Nishijima, M., and Akamatsu, Y. (1993) J. Biol. Chem. 268, 22908-22913) exhibits striking reductions in biosynthetic rate and cellular content of phosphatidylglycerol (PG) and CL and shows mitochondrial morphological and functional abnormalities. The CHO PGS-S mutant transfected with the CHO PGS1 cDNA exhibited 620-fold and 7-fold higher PGP synthase activity than mutant PGS-S and wild type CHO-K1 cells, respectively, and had a normal cellular content and rate of biosynthesis of PG and CL. In contrast to mutant PGS-S, the transfectant had morphologically normal mitochondria. When the transfectant and mutant PGS-S cells were cultivated in a glucose-depleted medium, in which cellular energy production mainly depends on mitochondrial function, the transformant but not mutant PGS-S was capable of growth. These results demonstrated that the morphological and functional defects displayed by the PGS-S mutant are due directly to the reduced ability to make normal levels of PG and/or CL.