Repair of a pseudarthrosis of the lumbar spine. A functional outcome study.

Eighty-six patients had a total of eighty-eight primary attempts at repair of a pseudarthrosis that had developed after a localized arthrodesis in the lumbar spine. A follow-up questionnaire was sent to all patients at a mean of fifty-one months (range, twenty-five to seventy-eight months) after the operation; seventy-two patients (84 percent) completed to questionnaire. A solid fusion was ultimately achieved after the treatment of eighty-one (94 percent) of the eighty-six pseudarthroses for which radiographic data were available. With the numbers available, we could find no significant association between a solid fusion and the patient's age, gender, body-mass index, return to work, or outcome score. Despite the high rate of fusion after the index repair and subsequent procedures, only nineteen (26 percent) of the seventy-two patients who completed the questionnaire eventually had a good or excellent outcome. Seven (10 percent) had an excellent result (90 to 100 points), twelve (17 percent) had a good result (70 to 89 points), fourteen (19 percent) had a fair result (50 to 69 points), and thirty-nine (54 percent) had a poor result (less than 50 points). Nevertheless, fifty-one patients (71 percent) reported that the operation led to some improvement, and fifty-five (76 percent) said that they would have the operation again if the circumstances were similar to those before the repair of the pseudarthrosis. Thirty-four of the seventy-two patients were smokers and thirty-eight were non-smokers at the time of the operation. There was a negative linear association between the outcome scores and the number of pack-years (p = 0.02). Cessation of smoking before the operation positively affected the outcome; the patients who had stopped smoking had a mean outcome score of 65 points, compared with 45 points for those who had not stopped (p = 0.03). Patients who had stopped smoking were also more likely to return to work full time (p < 0.001). At the latest follow-up evaluation, twenty of the seventy-two patients had returned to full-time employment. Patients who had been receiving Workers' Compensation at the time of the operation generally did poorly on the outcome questionnaire, but, with the numbers available, they did not have a significantly different rate of solid fusion than patients who had not been receiving Workers' Compensation. Also, the outcome score and the rate of fusion were nor significantly affected by age or by obesity.

Spine and scalp recordings as a function of intensity. A model for changes during spinal cord monitoring.

STUDY DESIGN: Spinal cord monitoring has used both spine and scalp recordings as indicators of spinal cord integrity. The relative merits of spine or scalp recordings to predict the quality of the afferent volley in the somatosensory pathway were addressed in this study by using various stimulus intensities as a way to model alterations of the size of the afferent volley. OBJECTIVES: The results were analyzed to determine the correlation of central recordings taken at the spine or scalp with peripheral recordings. SUMMARY OF BACKGROUND DATA: Spinal cord monitoring with somatosensory evoked potentials has been achieved with recordings of signals generated by either the spinal cord or the somatosensory cortex. Spine recordings are thought to be more stable, yet little evidence exists to document this statement. METHODS: Seven patients were studied in the course of standard intraoperative spinal cord monitoring. Responses were recorded at the popliteal fossa, thoracic epidural, cervical spine, and scalp to tibial nerve stimulation at intensities varying from 0.5 to 2.0 times muscle twitch threshold. RESULTS: Normalized amplitudes of the response at the popliteal fossa were used to reflect the magnitude of the afferent volley. The amplitudes of the popliteal fossa response showed a high correlation (r = 0.90) with normalized amplitudes of epidural and cervical spine responses and moderate correlation (r = 0.49) with normalized amplitudes of scalp responses. The width of the 95% confidence limits for the inverse prediction of the afferent volley from epidural and cervical responses was nearly a third narrower than that from scalp responses. At low stimulus intensities, scalp responses were consistently observed when spine responses were absent, and scalp responses had lower response thresholds than did spine responses. The latencies of the popliteal fossa responses were not well correlated with latencies of either the epidural or cervical responses. CONCLUSIONS: These correlation and inverse prediction data suggest that the size of an afferent volley may be predicted more accurately by spine responses than by scalp responses. The presence of scalp responses at intensities too low to elicit detectable spinal-level responses suggests that scalp responses may be considered a sensitive indicator of a minimal afferent volley.

Visual loss as a complication of spine surgery. A review of 37 cases.

STUDY DESIGN: Thirty-seven patients who experienced visual loss after spine surgery were identified through a survey of the members of the Scoliosis Research Society and a review of the recent literature. OBJECTIVES: Records were reviewed in an attempt to identify preoperative and intraoperative risk factors and to assess the likelihood of recovery. SUMMARY OF BACKGROUND DATA: Postoperative blindness after spine surgery has been documented in case reports or small series. The authors report the largest group of such cases to date and the first to allow conclusions regarding risk and prognosis. METHODS: Letters were sent to members of the Scoliosis Research Society requesting copies of medical records concerning patients who experienced postoperative visual deficits after spine surgery. An additional 10 well-documented recent cases were identified from published reports. RESULTS: Patients with visual loss had a mean age of 46.5 years. Surgery included instrumented posterior fusion in 92% of the cases, with an average operative time of 410 minutes and blood loss of 3500 mL. Most cases had significant intraoperative hypotension, with a mean drop in systolic blood pressure from 130 to 77 mm Hg. However, comparison with a matched group of patients with no visual symptoms showed no differences in the hematocrit or blood pressure values. Visual loss occurred because of ischemic optic neuropathy, retinal artery occlusion, or cerebral ischemia. Eleven cases were bilateral, and 15 patients had complete blindness in at least one eye. Most deficits were permanent. CONCLUSIONS: The authors conclude that blindness after spine surgery is more common than has been recognized previously. Most cases are associated with complex instrumented fusions.

Test of the equivalence principle using a rotating torsion balance.

We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Deltaa(N),(Be-Ti)=(0.6+/-3.1)x10(-15) m/s2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The Eötvös parameter is eta(Earth,Be-Ti)=(0.3+/-1.8)x10(-13). By analyzing our data for accelerations towards the center of the Milky Way we find equal attractions of Be and Ti towards galactic dark matter, yielding eta(DM,Be-Ti)=(-4+/-7)x10(-5). Space-fixed differential accelerations in any direction are limited to less than 8.8x10(-15) m/s2 with 95% confidence.

[Tolerance of preventive influenza vaccination with a subunit vaccine]. / Verträglichkeit der Influenza-Schutzimpfung mit einer Subunit-Vaccine.

The frequency and intensity of undesirable side effects after protective vaccination against influenza with a commercially available vaccine were studied. 82 gainfully employed persons of both sexes were questioned in respect of local reactions such as weal and flare reactions, itching, sensation of heat, tenderness on pressure, and impeded movement, as well as systemic reactions e.g. elevated temperature or fever, profound sweating, headache, malaise, and insomnia. In 61 of 82 questioned persons local reactions occurred within 24 hours after vaccination, mainly weal and flare reactions and tenderness on pressure. 10 persons had systemic reactions, chiefly headache and fever, 39 of the questioned persons who reported on undesirable effects considered these impairments to be slight, whereas 28 of the group did not feel that the impairments disturbed or upset them in any way.

Gravitropism and gravimorphism during regeneration from protoplasts of the moss Ceratodon purpureus (Hedw.) Brid.

Wild-type (WT) protonemata of the moss Ceratodon purpureus grow upwards in darkness (negative gravitropism), whereas protonemata of the mutant, wrong-way response (wwr-1) grow down. Since Ceratodon protoplasts regenerate to form new protonemata, we analyzed whether the direction of filament emergence was influenced by gravity (gravimorphism) and determined the cytological events that correlated with the onset of gravitropism in WT and wwr-1 filaments formed de novo. In the WT the direction of filament emergence appeared to be gravimorphic as more than 66% of the new filaments emerged above the horizontal. In contrast, the direction of filament emergence was random in wwr-1. Tip-growing cells of both genotypes became gravitropic within a total of one to two cell divisions. Gravitropic curvature in wwr-1 was opposite in direction to that of WT, and the timing of curvature was comparable, indicating that the wwr-1 mutation acts during the onset of gravitropic competence. In time-lapse studies of both genotypes, neither a plastid-free zone nor obvious and extensive plastid sedimentation characteristic of mature dark-grown protonemata was observed in the new filaments prior to gravitropic curvature. Thus, it appears that these latter two features are not required for gravitropism in new protonemal filaments from protoplasts.

Wall-associated kinases are expressed throughout plant development and are required for cell expansion.

The mechanism by which events in the angiosperm cell wall are communicated to the cytoplasm is not well characterized. A family of five Arabidopsis wall-associated kinases (WAKs) have the potential to provide a physical and signaling continuum between the cell wall and the cytoplasm. The WAKs have an active cytoplasmic protein kinase domain, span the plasma membrane, and contain an N terminus that binds the cell wall. We show here that WAKs are expressed at organ junctions, in shoot and root apical meristems, in expanding leaves, and in response to wall disturbances. Leaves expressing an antisense WAK gene have reduced WAK protein levels and exhibit a loss of cell expansion. WAKs are covalently bound to pectin in the cell wall, providing evidence that the binding of a structural carbohydrate by a receptor-like kinase may have significance in the control of cell expansion.

Azidomorphines and heterogenous opiate receptors.

The N-cyclopropylmethyl derivative of azidomorphine (CAM) was found to have strong opiate agonist and antagonist activity, in various in vitro and in vivo animal tests. The derivatives of azidomorphine were not only more potent analgesics than the corresponding members of the morphine family but their lipid solubility was also markedly improved: the ratios of the median effective subcutaneous/intracerebroventricular doses are between 6.2-22.0 in the azido-group, while that of morphine is 381. The antagonist potencies of N-cyclopropyl-N-allyl azidomorphine derivatives were also quantitatively estimated in oxymorphone righting test, and were found to possess antagonists activity as potent as naloxone and more potent than other opiate antagonists (nalorphine, pentazocine Mr-1452 etc.). CAM also has been shown to produce depression of acetylcholine release from the cat lateral cerebral ventricle similarly to morphine, in a naloxone reversible manner, regardless the applied stimulus (electrical stimulation of sciatic nerve, or ouabain perfusion). CAM, similarly to bremazocine, the reported kappa opioid agonist drug, markedly increased the urinary output in normally hydrated rats. This effect was reversed by high dose of naloxone, suggesting the kappa agonist action of CAM.

A positively gravitropic mutant mirrors the wild-type protonemal response in the moss Ceratodon purpureus.

Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90 degrees, they temporarily grow down soon after reorientation ("initial reversal") and also prior to cytokinesis ("mitotic reversal"). A positively gravitropic mutant designated wrong- way response (wwr-1) has been isolated by screening ultraviolet light-mutagenized Ceratodon protonemata. Protonemata of wwr-l reoriented from the vertical to the horizontal grow down with kinetics comparable to those of the wild-type. Protonemata of wwr-1 also show initial and mitotic reversals where they temporarily grow up. Thus, the direction of gravitropism, initial reversal, and mitotic reversal are coordinated though each are opposite in wwr-1 compared to the wild-type. Normal plastid zonation is still maintained in dark-grown wwr-1 apical cells, but the plastids are more numerous and plastid sedimentation is more pronounced. In addition, wwr-1 apical cells are wider and the tips greener than in the wild-type. These data suggest that a functional WWR gene product is not necessary for the establishment of some gravitropic polarity, for gravitropism, or for the coordination of the reversals. Thus, the WWR protein may normally transduce information about cell orientation.

WAKs: cell wall-associated kinases linking the cytoplasm to the extracellular matrix.

There are only a few proteins identified at the cell surface that could directly regulate plant cell wall functions. The cell wall-associated kinases (WAKs) of angiosperms physically link the plasma membrane to the carbohydrate matrix and are unique in that they have the potential to directly signal cellular events through their cytoplasmic kinase domain. In Arabidopsis there are five WAKs and each has a cytoplasmic serine/threonine protein kinase domain, spans the plasma membrane, and extends a domain into the cell wall. The WAK extracellular domain is variable among the five isoforms, and collectively the family is expressed in most vegetative tissues. WAK1 and WAK2 are the most ubiquitously and abundantly expressed of the five tandemly arrayed genes, and their messages are present in vegetative meristems, junctions of organ types, and areas of cell expansion. They are also induced by pathogen infection and wounding. Recent experiments demonstrate that antisense WAK expression leads to a reduction in WAK protein levels and the loss of cell expansion. A large amount of WAK is covalently linked to pectin, and most WAK that is bound to pectin is also phosphorylated. In addition, one WAK isoform binds to a secreted glycine-rich protein (GRP). The data support a model where WAK is bound to GRP as a phosphorylated kinase, and also binds to pectin. How WAKs are involved in signaling from the pectin extracellular matrix in coordination with GRPs will be key to our understanding of the cell wall's role in cell growth.

Characterization of a family of Arabidopsis genes related to xyloglucan fucosyltransferase1.

To understand primary cell wall assembly in Arabidopsis, we have focused on identifying and characterizing enzymes involved in xyloglucan biosynthesis. Nine genes (AtFUT2-10) were identified that share between 47% and 62% amino acid similarity with the xyloglucan-specific fucosyltransferase AtFUT1. Reverse transcriptase-PCR analysis indicates that all these genes are expressed. Bioinformatic analysis predicts that these family members are fucosyltransferases, and we first hypothesized that some may also be involved in xyloglucan biosynthesis. AtFUT3, AtFUT4, and AtFUT5 were expressed in tobacco (Nicotiana tabacum L. cv BY2) suspension culture cells, and the resulting proteins did not transfer fucose (Fuc) from GDP-Fuc to tamarind xyloglucan. AtFUT3, AtFUT4, and AtFUT5 were overexpressed in Arabidopsis plants. Leaves of plants overexpressing AtFUT4 or AtFUT5 contained more Fuc than wild-type plants. Stems of plants overexpressing AtFUT4 or AtFUT5 contained more xylose, less arabinose, and less galactose than wild-type plants. We suggest that the AtFUT family is likely to include fucosyltransferases important for the synthesis of wall carbohydrates. A targeted analysis of isolated cell wall matrix components from plants altered in expression of these proteins will help determine their specificity and biological function.