Comparison of ultrasonic cleaning schemes: a pilot study.

OBJECTIVE: Ultrasonic cleaning is an effective method for cleaning dental instruments prior to sterilisation. However, there are few studies that directly compare precleaning and ultrasonic cleaning solutions. This study evaluated the efficacy of different ultrasonic cleaning schemes. METHOD AND MATERIALS: Twenty representative dental instruments, five of which were soiled with a mixture of blood and hydroxyapatite, were used in a series of cleaning runs. Cleaning employed a presoaking agent, ultrasonic cleaning, or a combination of both. Two presoaking agents (Non-ionic Ultrasonic Cleaning Solution and ProEZ Foaming Enzymatic Spray) plus five ultrasonic cleaners (UltraDose, General Purpose Cleaner, Co-enzyme Concentrate, Enzol Enzymatic Detergent, and Non-ionic Ultrasonic Cleaning Solution) were compared, with tap water serving as a control. There were two cleaning times: seven and 15 minutes. After rinsing, the working ends of the instruments underwent scrubbing for 20 seconds using a dental polishing brush held in a haemostat. After scrubbing, the brush and instrument were placed in a tube containing sterile saline. Vortexing of the tube lasted 30 seconds. Testing for the post-cleaning presence of blood involved Hemastix dipsticks. These sticks measure minute amounts of blood in urine and can detect as few as 35 red blood cells per ml. Comparisons of colour change were made to a standard scale followed by assignment of numeric values. RESULTS: Tap water was the poorest cleaning solution, while UltraDose was the most effective. Blood removal improved when cleaning time was increased from seven to 15 minutes. The combined effect of a presoak immersion followed by ultrasonic cleaning was the most effective cleaning scheme overall. Cleaning by either ultrasound or presoaking only was less effective. Some instruments were more difficult to clean than others. CONCLUSION: Within the constraints of the small number of test runs performed, it was concluded that application of a presoak agent before ultrasonic cleaning produced the most effective instrument-cleaning regimen.     

Leukaemia Inhibitory Factor or Related Factors Promote the Differentiation of Neuronal and Astrocytic Precursors within the Developing Murine Spinal Cord

Previously we have shown that leukaemia inhibitory factor (LIF) potentiates the development of murine spinal cord neurons in vitro , suggesting that it, or related factors, may play an important regulatory role in neuronal development. We have further investigated this role and show here that the generation of neurons in cultures of embryonic day 10 spinal cord cells is inhibited by antibodies to the β subunit of the LIF receptor. Since there are more undifferentiated precursors in antibody-treated cultures than in control and LIF-treated cultures, it is concluded that the primary action of LIF, or related molecules, is to promote neuronal differentiation, not precursor survival. In addition, the failure of LIF to support neuronal survival in the period immediately following differentiation suggests that the increased numbers of neurons generated with LIF are not attributable to its neurotrophic action. By selecting neuronal precursors on the basis of their inability to express class I major histocompatibility complex molecules, it was shown that LIF acted directly upon these cells and not via an intermediary cell. LIF also appears to be involved in regulating the differentiation of astrocytes, since it increases the number of glial fibrillary protein (GFAP)-positive cells present in the cultures and since the spontaneous production of GFAP-positive cells is blocked by antibodies to the LIF β receptor. These findings suggest that LIF or related factors promote the differentiation of neural precursors in the spinal cord, but that they are not involved in preferentially promoting precursors down a specific differentiation pathway.     

Validity of a hinged constant force probe and a similar, immobilised probe in untreated periodontal disease

The validity of a hinged constant force probe (0.25 N) was compared with that of a similar but immobilised instrument, using the same interchangeable tip for both (0.64 mm diameter; 2 mm divisions). 60 sites were measured on teeth which were extracted subsequently, in patients with untreated periodontal disease, and the connective tissue attachment level was used as validity criterion. The clinical measurements of both probes correlated well with each other, but they differed significantly from the post-extraction connective tissue attachment level measurements, indicating a point 1.2 mm coronally to this, on average. A companion investigation of intra-operator probing depth reproducibility with the 2 probes, was undertaken in 14 patients, at 2 visits separated by 1 week in each case. All patients had untreated periodontal disease. A difference between probes was found at the first visit, but not at the second; the immobilised probe showed a difference between visits, reducing mean probing depth slightly at the second; when the immobilised probe was used first, there was a difference between probes. Further analysis of the results indicated that there was greatest agreement between probes when the constant force probe had been used before the immobilised probe at the second visit. The results suggested that these probes indicated a point above the connective tissue attachment level, related to pocket morphology, and that there was a moderate learning effect due to operator use of the constant force probe, which modified use of the immobilised probe.     

MANAGEMENT OF SEMINOMA OF THE TESTIS: RECOMMENDATIONS BASED ON TREATMENT RESULTS

Background : The results of management of seminoma of the testis at the Department of Radiation Oncology St Vincent's Hospital, Sydney were evaluated retrospectively to: (i) establish that outcomes were in keeping with published results from centres in Australia and overseas; (ii) assess the impact of chemotherapy on management; and (iii) to determine ‘best practice’ management protocols based on our results and a review of the relevant literature. Methods : (i) Assessment of treatment results for stage I and II seminoma of the testis treated by post-orchidectomy radiotherapy and/or chemotherapy at St Vincent's Hospital between 1979 and 1993; (ii) literature review of published data from Australian and overseas centres on the management of seminoma of the testis, and in particular the use of surveillance or chemotherapy either alone, at time of relapse or combined with radiotherapy; and (iii) development of recommendations for use as management protocols in our department. Results : Our data and a review of the literature suggest that post-orchidectomy radiotherapy with chemotherapy for relapse in stage I and IIA disease results in long-term cure rates approaching 100%. Treatment with chemotherapy either routinely or selectively or using a surveillance policy is unlikely to show any improvement in outcome and may be less cost-effective and/or produce increased morbidity and the risk of secondary leukaemia. For stage IIB disease (5–10 cm) the use of initial combination chemotherapy with or without subsequent radiotherapy did not appear to give better outcomes than initial radical radiotherapy alone, reserving chemotherapy or further radiotherapy for relapse. For bulkier stage IIB disease (> 10cm). the use of initial chemotherapy plus consolidation radiotherapy appeared to be an appropriate treatment. Conclusions : Management protocols for seminoma of the testis at St Vincent's Hospital, Sydney Department of Radiation Oncology currently are (i) stage I, IA and IIB (5–10 cm): post-orchidectomy radiotherapy alone with chemotherapy or further radiotherapy for relapse; and (ii) stage IIB (> 10 cm) disease: initial chemotherapy post-orchidectomy followed by radiotherapy to sites of initial disease involvement.     

Effect of training on postural control in figure skaters: a randomized controlled trial of neuromuscular versus basic off-ice training programs.

OBJECTIVES: To compare the effect of a neuromuscular training program and a basic exercise program on postural control in figure skaters. DESIGN: Two groups; parallel design; prospective, randomized controlled trial. SETTING: Postural control laboratory, arenas, September 2001 to December 2002. PARTICIPANTS: Forty-four young, healthy figure skaters (18 years +/- 3 years). INTERVENTIONS: Participants were randomly assigned to receive a neuromuscular training program (n = 22) or a basic exercise training program (n = 22). Both programs were completed 3 times per week for 4 weeks, and each session was supervised. MAIN OUTCOME MEASUREMENTS: Participants completed baseline and postintervention measures of postural control on a force plate. Postural control was quantified as the center of pressure (CoP) path length during tests of single-limb standing balance that mimicked figure skating skills and challenged the postural control system to varying degrees. The primary outcome measure was the CoP path length observed during a landing jump test completed with eyes closed. RESULTS: The post intervention CoP path lengths during the more challenging tests were significantly (P < 0.05) lower (indicating better postural control) for the neuromuscular trained group than for the basic exercise-trained group. For the landing jump test completed with eyes closed, the percent improvement in the neuromuscular trained group was significantly greater (mean = 21.0 +/- 22.0%) than the basic exercise trained group (mean = -4.9 +/- 24.9%; P < 0.05). The magnitude of improvement in the neuromuscular-trained group ranged from approximately 1% to 21%, depending on the specific postural control test used. CONCLUSIONS: The results suggest that off-ice neuromuscular training can significantly improve postural control in figure skaters, whereas basic exercise training does not.     

Safety and Efficacy of ECT in Depressed Patients with Dementia: A Review of Clinical Experience

The authors review the results of electroconvulsive therpay (ECT) in 135 cases of depression occurring in conjunction with organic dementia, subcortical leukoencephalopathy without dementia, and depressive dementia (22 cases). Overall, 86% had a positive therapeutic response to ECT, whereas 21% experienced significant cognitive or memory side effects, virtually all of which were transient and reversible. Forty-nine percent of the patients with organic or depressive dementias experienced improvement in cognitive or memory function consequent to ECT.     

Comparative uptake and retention of adriamycin andN-benzyladriamycin-14-valerate in human CEM leukemic lymphocyte cell cultures

Summary N-Benzyladriamycin-14-valerate (AD 198) is a new lipophilic adriamycin (ADR) analogue that shows marked therapeutic superiority to ADR in murine tumor model systems yet differs mechanistically from ADR in a number of ways. Among its other properties, AD 198 produces a delayed but profound effect on cell-cycle progression and a pattern of continuing DNA damage in cultured cells briefly exposed to the drug. Using radiolabeled drug forms and radioassays combined with HPLC separation and fluorimetric detection techniques, aspects of drug accumulation, biotransformation, and retention in cultured human CEM leukemic lymphocytes were studied, in part to determine a possible pharmacologic basis for the latent effects seen with this drug. In addition, the cellular pharmacology of AD 198 and ADR were comparatively examined under identical experimental conditions. When CEM cells were incubated with drug at equi-growth inhibitory/minimally cytotoxic concentrations (AD 198, 1.0 M; ADR, 0.1 M), a number of differences were apparent. Under conditions of continuous 24-h drug exposure, a slow cellular accumulation and equilibration was observed with ADR (cell: medium equilibrium, 1:11 after 4–6 h), whereas the uptake of AD 198 was rapid and extensive (cell: medium equilibrium, 3:1 within 30 min). In drug-retention studies, when cells were pretreated at the same drug concentrations as before (AD 198 for 1 h; ADR for 4 h) and then transferred to drug-free media, both compounds re-equilibrated their intracellular drug content with the fresh media, losing about 50% of their respective anthracycline levels. Liquid chromatographic analysis of ADR-treated cultures under both sets of conditions showed the parent drug to be the only intracellular anthracycline species, whereas analysis of AD 198-treated cultures revealed two fluorescent signals corresponding to the parent drug and its 14-deesterified biotransformation product,N-benzyladriamycin (AD 288). Levels of AD 288 rose from 2% of the total intracellular anthracycline content immediately on drug admixture to 61% following 24 h continuous drug exposure and to 69% at 24 h in cells exposed to drug for 1 h and then continued in drug-free media for 24 h. At all times, the balance of the intracellular anthracycline fluorescence was attributable to the parent drug; no ADR was detectable in AD 198-treated cells by either fluorescence detection or radioassay. Thus, AD 198 is not a prodrug form of ADR, and the in vitro effects of this agent, including the latent effects on cell-cycle inhibition and DNA damage seen in cells following short-term drug exposure, can be explained on the basis of the high levels of active parent drug and biotransformation product that accumulate and persist in the cells.Abbreviations ADR adriamycin (doxorubicin) - AD 198 N-benzyladriamycin-14-valerate - AD 288 N-benzyladriamycin - AD 32 N-trifluoroacetyladriamycin-14-valerate - AD 143 N-trifluoroacetyladriamycin-14-0-hemiadipate - AD 41 N-trifluoroacetyladriamycin - [¹⁴C]-AD 198 [benzyl]--methylene-¹⁴C]-N-benzyladriamycin-14-valerate - [¹⁴C]-ADR [14-¹⁴C]-adriamycin - HPLC high-performance liquid chromatography - TLC thin-layer chromatography - DMSO dimethylsulfoxide - S-MEM Eagle's minimum essential medium for suspension culture - PBS phosphate-buffered saline (pH 7.0)     

Effects of muscimol inactivation of the cerebellar nuclei on precision grip

A single monkey was trained to perform a grasp, lift, and hold task in which a stationary hand- held object was sometimes subjected to brief, predictable force-pulse perturbations. The displacement, grip, and lifting forces were measured as well the three-dimensional forces and torques to quantify specific motor deficits after reversible inactivation of the cerebellar nuclei. A prior single-cell recording study in the same monkey provided the stereotaxic coordinates used to guide intranuclear injections of muscimol. In total, 34 penetrations were performed at 28 different loci throughout the cerebellar nuclei. On each penetration, two 1.0-microl injections of 5 microg/microl muscimol, were made 1.0 mm apart either within the nuclei or in the white matter just lateral or posterior to the dentate nucleus. Injections in the region corresponding to the anterior interpositus nucleus produced pronounced dynamic tremor and dysmetric movements of the ipsilateral arm when the animal performed unrestrained reaching and grasping movements. In contrast, no relatively short-latency (15-20 min.) deficits were observed after injection in the dentate nucleus, although some effects were observed after several hours. When tested in a primate chair with the forearm supported and restrained at the wrist and elbow, the monkey performed the lift and hold task without tremor or dysmetria. However, with the restraint removed, the forces and torques applied to the manipulandum were poorly controlled and erratic. The monkey's arm was ataxic and a 5-Hz intention tremor was clearly visible. In addition, the animal was generally unable to compensate for the predictable perturbations and the anticipatory grip force increases were absent. However, overall the results suggest that reversible cerebellar nuclear inactivation with muscimol has little effect on isolated distal movements of the wrist and fingers.