Using motion capture technology to measure the effects of magnification loupes on dental operator posture: A pilot study.

BACKGROUND: Motion analysis has great potential for quantitatively evaluating dental operator posture and the impact of interventions such as magnification loupes on posture and subsequent development of musculoskeletal disorders. OBJECTIVE: This study sought to determine the feasibility of motion capture technology for measurement of dental operator posture and examine the impact that different styles of magnification loupes had on dental operator posture. METHODS: Forward and lateral head flexion were measured for two different operators while completing a periodontal probing procedure. Each was measured while wearing magnification loupes (flip up-FL and through the lens-TTL) and basic safety lenses. RESULTS: Operators both exhibited reduced forward flexion range of motion (ROM) when using loupes (TTL or FL) compared to a baseline lens (BL). In contrast to forward flexion, no consistent trends were observed for lateral flexion between subjects. CONCLUSIONS: The researchers can report that it is possible to measure dental operator posture using motion capture technology. More study is needed to determine which type of magnification loupes (FL or TTL) are superior in improving dental operator posture. Some evidence was found supporting that the quality of operator posture may more likely be related to the use of magnification loupes, rather than the specific type of lenses worn.

Evidence for hydroxyl radical generation by human Monocytes.

A number of highly reactive oxygen species have been implicated in the oxygen-dependent mechanisms involved in bactericidal activity of phagocytic leukocytes. Hydrogen peroxide and superoxide, two agents known to occur during phagocytosis, are thought to interact to generate hydroxyl radical, singlet oxygen, and other potentially reactive molecules. Using an assay system of ethylene generation from methional, cell preparations of human monocytes were demonstrated to generate hydroxyl radical or a similar agent during phagocytosis of zymosan particles. The generation of ethylene was impaired by agents which reduce superoxide or hydrogen peroxide concentrations as well as by agents reported to be hydroxyl radical scavengers. The ethylene generation did not appear to be dependent on myeloperoxidase in that azide enhanced ethylene generation. Monocytes from a patient with chronic granulomatous disease failed to generate ethylene during phagocytosis. This assay technique may be useful in exploring the metabolic events integral to the bactericidal and inflammatory activity of phagocytic leukocytes.

A comparison of the metabolic response to phagocytosis in human granulocytes and monocytes.

Recent studies indicate that oxygen radicals such as superoxide or singlet oxygen may be important in the functional activity of human granulocytes. We have examined the possible importance of these radicals in the functional capacity of human blood monocytes. Monocytes, like granulocytes, generate chemiluminescence during phagocytosis. Chemiluminescence is impaired 50-90% by superoxide dismutase, an enzyme which enhances the dismutation of superoxide to hydrogen peroxide. These results indicate that superoxide is related to the chemiluminescence generated by monocytes. Superoxide dismutase in a concentration which impaired chemiluminescence also impaired the staphylococcal killing by monocytes. Hexose monophosphate shunt activity and hydrogen peroxide production by granulocytes and monocytes were also evaluated. The oxidation of [1-14C]glucose was used as a measure of hexose monophosphate shunt activity and the oxidation of [14C]formate as an estimation of hydrogen peroxide production. The oxidation of both substrates by monocytes was increased during phagocytosis but, in contrast to results in granulocytes, was not further increased by the addition of superoxide dismutase. These data indicate that superoxide may be important in bactericidal activity of human monocytes. Our results also suggest that the metabolism of oxygen radicals in monocytes and granulocytes may be different.

Immune function of successfully treated lymphoma patients.

Immunologic function was evaluated in 12 patients with Hodgkin's disease and 5 patients with lymphocytic lymphoma who had been successfully treated with either chemotherapy, radiation therapy, or both of these modalities 3-42 mo previously. Only two of the patients were found to have total anergy to a battery of six recall skin test antigens and all were responsive to skin testing with phytohemagglutinin. However, 10 of 16 patients were unable to develop delayed cutaneous hypersensitivity to either of the neoantigens dinitrochlorobenzene or keyhole limpet hemocyanin. Four other patients developed reactivity to only one of these neoantigens for a total of 14 of 16 (88%) of the patients demonstrating some impairment in neoantigen response. Total lymphocyte, T-lymphocyte, B-lymphocyte, and null cell numbers, as well as serum immunoglobulins were quantitatively normal. Monocyte numbers, chemotaxis, and Fc receptor activity were normal. Monocyte staphylocidal activity at 60 min was modestly depressed and candidacidal activity was depressed in those receiving both chemotherapy and radiation therapy. Spontaneous (unstimulated) lymphocyte [3H]thymidine incorporation was low in the patients as a group and lymphoblastic transformation to specific antigens was impaired in 11 of 17 patients who had positive skin test reactions to the same antigen. Highly significant suppression of lymphoblastic transformation was noted after stimulation by the mitogens phytohemagglutinin, pokeweed, and concanavalin-A. The greatest impairment of mitogen response was seen in those patients receiving both chemotherapy and radiation therapy. These data demonstrate specific impairments of neoantigen processing, lymphocyte function, and to a lesser extent monocyte function in successfully treated patients with lymphoma. These impairments may contribute to the increased incidence of infections and second primary malignancies in these patients.

Topology of ascending brainstem projections to nucleus parabrachialis in the cat.

The afferent projections to nucleus parabrachialis (NPB) and nearby pontine areas from the lower brainstem were studied in cats using retrograde horseradish peoxidase (HRP) and anterograde autoradiographic tracing techniques. Two groups of medullary neurons send major projections to NPB and the Kölliker-Fuse nucleus (KF): 1) the solitary complex, especially the medial nucleus of the solitary tract (SM), nearby smaller cells of the dorsal motor nucleus of the vagus (DMV) and the commissural nucleus; and 2) the lateral tegmental field (FTL), or parvocellular reticular formation. Autoradiographic tracing from these areas demonstrated terminal fields in NPB/KF and emphasized a ventrolateral route to NPB from both sources, with axons ascending between the facial nerve and superior olive and passing rostral to the trigeminal nuclei. Minor projections to NBPB/KF originate in the ventrolateral nucleus of the solitary tract, area subpostrema, the alaminar spinal trigeminal nucleus, the gigantocellular and magnocellular tegmental fields, and an area dorsal to the ipsilateral inferior olive. Topographical features of the major projections were studied by correlating the locus of overlap of injection sites with the locations of HRP-positive cells. Medial areas of SM/DMV project mostly to medial parts of NPB, while lateral areas near the solitary tract project to lateral parts of NPB and KF. Crossing projections from SM/DMV favor dorsolateral NPB and KF. FTL neurons in dorsomedial areas project more to medial NPB, and ventrolateral areas project to lateral NPB/KF. Using a new coordinate system to locate and normalize the positions of FTL neurons, data from many brains were collated. FTL cells projecting to NPB/KF were found to be on discrete longitudinal sheets, running radially with respect to the fourth ventricle. This substructure and related evidence suggest a preferred pattern for neuroanatomical connections and information processing in the lateral reticular areas of the brainstem, and help in understanding the topography of the projections to NPB/KF.

Leukemic reticuloendotheliosis. A study of the origin of the malignant cell.

A highly pure preparation of neoplastic cells from the spleen of a patient with leukemic reticuloendotheliosis was studied for function, membrane characteristics and glucose metabolism. Glass adherence and phagocytosis of small particles (latex and carbon black) were demonstrated with phase contrast microscopy. Staphylocidal activity was similar to that of normal monocytes. Immunofluorescent assays revealed nonspecific uptake of antiserums to immunoglobulins G (IgG), M (IgM), A (IgA) and kappa and kappa and lambda light chains. Rosette assays indicated the presence of receptors for IgG on the surface of all cells but no receptors for complement (C3) or sheep red blood cells. Glucose metabolic studies revealed a pattern that differed from that of normal monocytes or lymphocytes with intermediate values for glycolysis, low hexose monophosphate shunt activity and high Krebs cycle activity. Increments in tritiated (3H)-thymidine uptake and glucose metabolism in response to phytohemagglutinin stimulation were minimal (5 per cent of normal lymphocyte values) and no response was noted with pokeweed mitogen stimulation. These findings suggest that the leukemic reticuloendotheliosis cell most closely resembles cells of the monocyte-histiocyte series.

A simple automated solution for removing and applying sealing microplate lids.

With the improved reliability and efficiency of automation, there has been an increased desire to integrate automated sample management with automated screening systems. In order to store samples "on line" for an extended period of time, an automation-compatible means for sealing and unsealing microplates is necessary. Numerous commercial solutions are available for removing loose-fitting microplate lids; however, the task of removing a tight-fitting matted lid such as the RoboLid is more challenging. This paper discusses the design of an automated workstation for the application and removal of such tight-fitting microplate lids.

Biocarbon ureterostomy device for urinary diversion. Multicenter clinical trial.

The bioCarbon ureterostomy device is a stomal prosthesis for upper tract urinary diversion that has had preliminary successes in animal and human trials in Europe and Peru. Implantation of a pure carbon stomal prosthesis offers the potential advantages of high biocompatibility, lack of encrustation, and elimination of stomal stenosis which is frequently associated with cutaneous ureterostomy. Nine bioCarbon ureterostomy devices were implanted from August, 1984 through July, 1985. Although successful implantation was achieved in 2 patients, the complication rate was high. The bioCarbon ureterostomy device has potential as an alternative form of urinary diversion. However, significant problems need to be remedied before it can be recommended for routine clinical application.

An electrophysiological study of medullary neurons projecting to nucleus parabrachialis of the cat.

Neuronal activity was recorded from a total of 868 cells in the medulla of cats in regions known to project to nucleus parabrachialis (NPB) of the pons and thought to be involved in respiration. Of 196 neurons antidromically (85) or synaptically (111) activated from NPB, 178 were silent in the decerebrate or barbiturate-anesthetized preparation, and could not be induced to activity by increasing CO2, activating Breuer-Hering reflexes, stimulation of the vagus or vagotomy. We conclude that the direct pathway from the lateral tegmental field of the medulla to NPB is not significantly involved in respiratory function in these preparations.

Types and locations of respiratory-related neurons in lateral tegmental field of cat medulla oblongata.

Extracellular microelectrode recordings were made from a total of 868 neurons in the medullas of cats in regions known to contain high densities of respiratory-related neurons (solitary tract complex, nucleus ambiguus/retroambigualis, lateral tegmental field). Both the discharge patterns and the locations of units were noted and correlated with a recently described substructure of the tegmental field of the cat medulla in which neuronal cell bodies are found associated with sheets of blood vessels supplying the brainstem. The majority of cells were phasically firing (59%) with activity confined to either the inspiratory or the expiratory phase, 21% were tonically firing cells with no discernible respiratory modulation and 20% were silent neurons, responsive to electrical stimulation of the vagus nerves or the dorsolateral pons in the vicinity of nucleus parabrachialis, but not to various respiratory stimuli. Within the solitary tract complex inspiratory discharge patterns were predominant (94%), while in nucleus ambiguus/retroambigualis 26% of the neurons had expiratory patterns with the rest being inspiratory (68%) or tonic (6%). Within the lateral tegmental field, the percentages of inspiratory, expiratory and tonic patterns were 51, 9 and 40%. Thus, inspiratory type patterns were found throughout the medulla, but expiratory patterns were most common in the ambiguus/retroambigualis nuclei. Found within all 3 major regions, but primarily within the lateral tegmental field of the rostral medulla were neurons that discharged with a brief burst at the inspiratory to expiratory phase transition. These cells had properties consistent with the off-switch mechanism: extreme late-inspiratory onset of discharge with the onset time being delayed by lung inflation, peak discharge at or slightly after the peak activity of the diaphragmatic EMG and a discharge rate which was insensitive to lung inflation. Within the lateral tegmental field, where longitudinal sheets of blood vessels running radially with respect to the IVth ventricle have been described, it was found that 85% of the tonically active units and 93% of the respiratory modulated cells were located less than 200 microns from the planes of these sheets. In addition, 87% of the neurons that could be antidromically or synaptically activated from the dorsolateral rostral pons were similarly located.

The effects of noxious heat on responses of spinocervical units to low intensity cutaneous stimuli.

The responses of spinocervical neurons to sinusoidal hair displacements were studied during and in the absence of radiant heating of parts of the hindpaw to noxious levels (45-65 degrees C). Noxious heat usually increased background discharge and lowered the signal-to-noise ratio at low frequencies of hair displacement. At higher frequencies over 20 Hz, this ratio was slightly depressed for half of the cells, and dramatically increased for the others. Similar effects were found when the heating was off the receptive field for hair displacement, which suggests a central cause for these effects.

Clinical evaluation of paresthesia steering with a new system for spinal cord stimulation.

OBJECTIVE: The goal was to evaluate, in a clinical study, the predicted performance of the transverse tripolar system for spinal cord stimulation, particularly the steering of paresthesia, paresthesia coverage, and the therapeutic range of stimulation. METHODS: Six transverse tripolar electrodes were implanted in the lower thoracic region in four patients experiencing chronic neuropathic pain. Electrode positions, relative to the spinal cord, were estimated from computed tomographic scans. A dual-channel stimulator was used for initial percutaneous tests, and an implanted single-channel stimulator was used for follow-up test sessions. Nine "balance" settings and several cathode-anode combinations were used with the dual-channel and single-channel stimulator, respectively. In each test, the increase of paresthesia coverage from the perception threshold to the discomfort threshold was registered on a body map and the corresponding voltages were recorded. RESULTS: Paresthesia steering occurred in all but one patient. The normalized steering score, enabling quantitative comparisons of paresthesia steering among tests and patients, showed that maximum paresthesia steering occurred when the electrode was at least 3 mm dorsal to the spinal cord and centered <2 mm from its midline. Paresthesia coverage included 70 to 100% of the body up to the electrode level, unless the electrode migrated or had broken wires. The therapeutic range, defined as the discomfort/perception of paresthesia threshold ratio, varied from 1.6 to 4.0. CONCLUSION: The clinical performance of transverse tripolar stimulation is in accordance with the characteristics predicted by computer modeling. It enables finer control of paresthesia than that achieved by polarity changes in conventional spinal cord stimulation systems.

Combination therapy protocol for stage III or IV carcinoma of the oral cavity, oropharynx and hypopharynx.

Combined therapy programs have improved recurrent and nodal metastatic rates but have not controlled distant metastases. A pilot study undertaken at Ohio State University evaluated the feasibility of adding chemotherapy to a combined modality regimen. The first phase determined that the toxicity of a four-drug combination chemotherapy yielded a favorable risk/benefit ratio and justified its inclusion in a protocol for untreated cancers. The second phase evaluated chemotherapy followed by surgery and postoperative irradiaation for untreated Stage III and IV epidermoid carcinoma of the oral cavity, oropharynx or hypopharynx. The overall chemotherapy response rate is 88% (22/25) with 6 complete and 16 partial responses. Evaluation of pathology specimens revealed 7 of 14 primary sites and 4 of 15 neck specimens had no histologic evidence of carcinoma. In the 10 patients who received all 3 modalities, 9 are free of disease (6 to 17 mo. follow-up).

Estimation of fiber diameters in the spinal dorsal columns from clinical data.

Lack of human morphometric data regarding the largest nerve fibers in the dorsal columns (DC's) of the spinal cord has lead to the estimation of the diameters of these fibers from clinical data retrieved from patients with a new spinal cord stimulation (SCS) system. These patients indicated the perception threshold of stimulation induced paresthesia in various body segments, while the stimulation amplitude was increased. The fiber diameters were calculated with a computer model, developed to calculate the effects of SCS on spinal nerve fibers. This computer model consists of two parts: 1) a three-dimensional (3-D) volume conductor model of a spinal cord segment in which the potential distribution due to electrical stimulation is calculated and 2) an electrical equivalent cable model of myelinated nerve fiber, which uses the calculated potential field to determine the threshold stimulus needed for activation. It is shown that the largest fibers in the medial DC's are significantly smaller than the largest fibers in the lateral parts. This finding is in accordance with the fiber distribution in cat, derived from the corresponding propagation velocities. Moreover, it is shown that the mediolateral increase in fiber diameter is mainly confined to the lateral parts of the DC's. Implementation of this mediolateral fiber diameter distribution of the DC's in the computer model enables the prediction of the recruitment order of dermatomal paresthesias following increasing electrical stimulation amplitude.

Changes in the Breuer-Hering reflexes following rostral pontine lesion.

The lung stretch reflex characteristics of unanesthetized decerebrate cats were determined using servo-controlled lung volume changes before and after bilateral lesion of the dorsolateral rostral pons in the region of nucleus parabrachialis medialis (NPBM). During the inspiratory phase the time-dependent threshold curve for inspiratory inhibition by lung inflation was shifted to larger volumes after lesion with no change in the constant describing its rate of decay. During the expiratory phase the gain of the inflation reflex was found to be increased by lesion, but otherwise to remain qualitatively the same. Deflations during the expiratory phase revealed a prolonged central inhibitory state with reduced rate of decay late in expiration. It is concluded that with intact vagi structures in the region of NPBM constitute but one of at least three sources of inspiratory inhibition, feedback derived from peripheral lung stretch receptors and from caudal pontine or medullary neurons also being involved. It is also concluded that the structures in the vicinity of NPBM affect the switching mechanisms differently during the two phases of the cycle: During inspiration they contribute a tonic threshold lowering input to the inspiratory "off-switch"; whereas, during expiration they provide inspiratory-facilitatory influences late in the phase.

Superoxide generation by human monocytes and macrophages.

Intracellular and extracellular superoxide (O2.-) generation by human monocytes and macrophages was quantitated by the nitroblue tetrazolium (NBT) reduction method. Human monocytes reduced 4.4 +/- 0.9 nmoles/10(6) cells/15 minutes with an increase to 12.4 +/- 1.3 during phagocytosis of zymosan. Based on inhibition by superoxide dismutase, superoxide generation of these cells was 1.8 +/- 0.9 nmoles in the resting state and 16.8 +/- 2.8 nmoles with zymosan phagocytosis. Human macrophages obtained by thoracentesis had comparable levels of NBT reduction and O2.-generation. Monocytes from a patient with chronic granulomatous disease demonstrated no increment in O2.-production during phagocytosis. Thus, human monocytes and macrophages appear capable of generating substantial amounts of O2.-during phagocytosis which may play an important role in bactericidal and other cell functions.

Normal human monocytes inhibit tumor cell growth in vitro.

Normal human monocytes were evaluated in an in vitro assay of growth inhibition of tumor cells. Monocytes were isolated from the blood of 6 normal subjects by Ficoll-Hypaque separation and adherence to plastic microtest wells. Cervical carcinoma cells (HeLa) were added to the microwells to result in a ratio of 50 monocytes to one HeLa cell. Cultures were then incubated for 6 to 46 hr. Growth inhibition was evaluated by measuring the uptake of 3H-thymidine over a 4-hr pulse period after 2, 18, or 42 hr of monocyte-HeLa interaction. Inhibition of HeLa growth by monocytes was 23.8% +/- 8.6% over 6 hr, 22.0% +/- 8.9% over 22 hr. and 68.3% +/- 7.5% over 46 hr. Growth inhibition of HeLa cells was confirmed by direct enumeration of HeLa cells at the end of coincubation. Attachment of monocytes to the HeLa cells was confirmed by light and scanning electron micrographs. Granulocytes, lymphocytes, and other cell lines did not comparably inhibit HeLa growth and media replenishment did not ablate the effect. These data demonstrate that normal human monocytes can inhibit the growth of a malignant cell line in vitro in the absence of overt activation procedures.

Human monocyte glucose metabolism in lymphoma.

Glycolysis (GU), hexose monophosphate shunt (HMPS) activity, and Krebs cycle activity were determined in monocytes from 32 normal subjects and 22 untreated patients with lymphoma. All of these parameters of glucose metabolism were significantly elevated in the lymphoma patients as a group when compared to normal subjects, suggesting monocyte activation by lymphoma. When the results were evaluated on the basis of sex and age, significant enhancement of glucose metabolism by lymphoma was evident in the 13 male patients compared to 18 normal men but not in monocytes from nine women with lymphoma compared to 14 normal subjects. Male patients over and under 40 years of age had significantly enhanced HMPS activity compared to normal subjects (p less than 0.05 and p less than 0.01, respectively), and GU was significantly increased in patients over 40 years (p less than 0.01). In contrast, no significant differences were noted in any of the values of women with lymphoma compared to normal subjects matched according to menstrual status. This discrepancy is apparently due to the high values for HMPS noted in healthy women, especially menstruating women. Although lymphoma may activate monocyte glucose metabolism, this effect can be masked by the normally high values seen in healthy women. The sex of the subject must be considered in evaluating human monocyte function and metabolism.