Population Health Management in Radiology: Economic Considerations

There is a growing emphasis on population health management (PHM) in the United States, in part because it has the worst health outcomes indices among high-income countries despite spending by far the most on health care. Successful PHM is expected to lead to a healthier population with reduced health care utilization and cost. The role of radiology in PHM is increasingly being recognized, including efforts in care coordination, secondary prevention, and appropriate imaging utilization, among others. To further discuss economic considerations for PHM, we must understand the evolving health care payer environment, which combines fee-for-service and increasingly, an alternative payment model framework developed by the Health Care Payment Learning and Action Network. In considering the term "value-based care," perceived value needs to accrue to those who ultimately pay for care, which is more commonly employers and the government. This perspective drives the design of alternative payment models and thus should be taken into consideration to ensure sustainable practice models.

Representation of women among leadership and honorees within the Society of Abdominal Radiology, past and present

PURPOSE

To evaluate gender diversity over time within the leadership and honorees of the Society of Abdominal Radiology with comparison to other radiologic societies.

METHODS

This was a retrospective, observational study of the gender distribution of presidents and gold meal awardees within the Society of Abdominal Radiology (SAR) compared to three national radiology organizations: the American College of Radiology (ACR), the American Roentgen Ray Society (ARRS), and the Radiological Society of North America (RSNA). Data were collected from the inception of each society through 2020. Societies were directly contacted for president and Gold Medal awardee names when this information was not available on society websites. Differences in the proportion of female presidents and Gold Medal awardees before and after 2012, by society, were performed using χ² test; 2012 was selected as a threshold year as this represented when SAR was created.

RESULTS

The proportion of female past presidents was 5%, 9%, and 33% for the SGR, SUR, and SAR, respectively, and 5%, 4%, and 7% for the ACR, ARRS, and RSNA, respectively. The proportion of female Gold Medal awardees was 5%, 4%, and 10% for the SGR, SUR, and SAR, respectively, and 5%, 7%, and 7%, respectively, for ACR, ARRS, and RSNA. There was a statistically significant increase in the proportion of women presidents and honorees in all societies after 2012 compared to before 2012, but no significant difference between societies in either time period.

CONCLUSION

A higher proportion of female presidents and honorees were demonstrated across all societies after 2012.

Society of Abdominal Radiology Disease Focused Panel Survey on Clinical Utilization of Incidental Pancreatic Cyst Management Recommendations and Template Reporting

OBJECTIVE

To assess current practice patterns with respect to protocols used for incidental pancreatic cyst follow-up, management guidelines, and template reporting.

METHODS

The Society of Abdominal Radiology Disease Focused Panel on intraductal pancreatic neoplasms distributed an anonymous 14-question survey to its members in June 2018 that focused on current utilization of incidental pancreatic cyst guidelines, protocols, and template reporting.

RESULTS

Among the 1,390 email invitations, 323 responded, and 94.7% (306 of 323) completed all questions. Respondents were mainly radiologists (93.8%, 303 of 323) from academic institutions (74.7%, 227 of 304) in North America (93.7%, 286 of 305). Of respondents, 42.5% (136 of 320) preferred 2017 ACR recommendations, 17.8% (57 of 320) homegrown systems, 15.0% (48 of 320) Fukuoka guidelines, and 7.8% (25 of 320) American Gastroenterological Association guidelines. The majority (68.7%, 222 of 323) agreed or strongly agreed that developing a single international consensus recommendation for management was important, and most radiologists preferred to include them in reports (231 of 322, 71.7%); yet only half included recommendations in >75% of reports (161 of 321). MR cholangiopancreatography was the modality of choice for follow-up of <2.5 cm cysts. Intravenous contrast was routinely used by 69.7% (212 of 304). Standardized reporting templates were rarely used in practice (12.8% 39 of 306).

CONCLUSIONS

Nearly 7 of 10 radiologists desire a unified international consensus recommendation for management of incidental cystic pancreatic lesions; ACR 2017 recommendations are most commonly used, followed by homegrown systems and Fukuoka guidelines. The majority of radiologists routinely use MR cholangiopancreatography with intravenous contrast for follow-up of incidental cystic lesions, but template reporting is rarely used.

A titanic drug resistance threat in Cryptococcus neoformans

Increasing resistance to frontline antifungals is a growing threat to global health. In the face of high rates of relapse for patients with cryptococcal meningitis and frequent drug resistance in clinical isolates, recent insights into Cryptococcus neoformans morphogenesis and genome plasticity take on new and urgent meaning. Here we review the state of the understanding of mechanisms of drug resistance in the context of host-relevant changes in Cryptococcus morphology and cell ploidy.

Brassinosteroid biosynthesis, stress resistance in plants, and application of brassinosteroids in plant biotechnology

Brassinosteroids (BRs) are newly discovered plant hormones that protect the plants from biotic and abiotic stress. Plants produce these hormones at all times, however, the quantity and location of their production vary. It has been demonstrated that BRs help the plants to regulate their response to stress conditions and make them more resistant to pest attack, extreme hot or cold environment, water scarcity, and salinity, among other types of stress. Manipulation of genes involved in the synthesis of BRs in different plants is a feasible strategy for genetic improvement of crop production and stress tolerance.

IL-36 and IL-1/IL-17 Drive Immunity to Oral Candidiasis via Parallel Mechanisms

Protection against microbial infection by the induction of inflammation is a key function of the IL-1 superfamily, including both classical IL-1 and the new IL-36 cytokine families. Candida albicans is a frequent human fungal pathogen causing mucosal infections. Although the initiators and effectors important in protective host responses to C. albicans are well described, the key players in driving these responses remain poorly defined. Recent work has identified a central role played by IL-1 in inducing innate Type-17 immune responses to clear C. albicans infections. Despite this, lack of IL-1 signaling does not result in complete loss of immunity, indicating that there are other factors involved in mediating protection to this fungus. In this study, we identify IL-36 cytokines as a new player in these responses. We show that C. albicans infection of the oral mucosa induces the production of IL-36. As with IL-1α/β, induction of epithelial IL-36 depends on the hypha-associated peptide toxin Candidalysin. Epithelial IL-36 gene expression requires p38-MAPK/c-Fos, NF-κB, and PI3K signaling and is regulated by the MAPK phosphatase MKP1. Oral candidiasis in IL-36R-/- mice shows increased fungal burdens and reduced IL-23 gene expression, indicating a key role played by IL-36 and IL-23 in innate protective responses to this fungus. Strikingly, we observed no impact on gene expression of IL-17 or IL-17-dependent genes, indicating that this protection occurs via an alternative pathway to IL-1-driven immunity. Thus, IL-1 and IL-36 represent parallel epithelial cell-driven protective pathways in immunity to oral C. albicans infection.

Effect of localised vibration on muscle strength in healthy adults: a systematic review

OBJECTIVE

To investigate the effects of local vibration on muscle strength in healthy adults.

DATA SOURCES

The electronic databases PubMed, CINAHL, Scopus and Web of Science were searched using a combination of the following keywords: vibration, vibration therapy, power, maximal voluntary contraction, performance, rate of force development and vibratory exercise. In addition, the Medical Subject Headings 'vibration', 'strength' and 'exercise' were used. The bibliographical search was limited to articles published in English.

STUDY SELECTION

Trials that evaluated the effect of localised vibration on muscle strength in healthy humans were included.

DATA EXTRACTION

Two independent evaluators verified the quality of the selected studies using the PEDro Scale and the Cochrane Collaboration's tool for assessing the risk of bias. Muscle strength was calculated for each intervention.

RESULTS

In total, 29 full-text studies were assessed for eligibility. Eighteen studies did not match the inclusion criteria, and were excluded. The 11 studies included in this review had an average PEDro score of 5.36/10. Most of the studies reported significant improvements in muscle strength after the application of local vibration. There was considerable variation in the vibration training parameters and target muscle location.

CONCLUSIONS

The use of local vibration on the target muscle can enhance muscle strength in healthy adults. Further well-designed controlled studies are required to confirm the effect of local vibration training on muscle strength.

Effect of quadriceps and hamstrings muscle cooling on standing balance in healthy young men

OBJECTIVE

The present study compared the effect of quadriceps and hamstring muscle cooling on standing balance in healthy young men.

METHODS

Thirty healthy young men (18-30 years) participated in the study. The participants were randomly assigned to three groups (n=10 each): quadriceps cooling (QC), hamstring cooling (HC), or control group (no cooling). Participants in the QC and HC groups received 20 minutes of cooling using a cold pack (gel pack), placed on the anterior thigh (from the apex of the patella to the mid-thigh) and the posterior thigh (from the base of the popliteal fossa to the mid-thigh), respectively. Balance score including unilateral stance was measured at baseline and immediately after the application of the cold pack.

RESULTS

No significant difference in the balance score was noted in any group after the application of the cold pack (p⟩0.05). Similarly, no significant differences in post-test balance score were noted among the three groups (p⟩0.05).

CONCLUSIONS

Cooling of the quadriceps and hamstring muscles has no immediate effect on standing balance in healthy young men. However, longitudinal studies are warranted to investigate the long-term effects of cooling these muscles on standing balance.

Renal nerve stimulation for treatment of neurocardiogenic syncope: a review from perspective of commercialization potential

A strong evidence of outcomes for vasovagal syncope is not easily identified. It would seem reasonable that the proposed Mayo Clinic technology would be reserved for cases with severe recurrent or refractory syncope. However, recurrence levels are relatively low, and while some predictive methods have been proposed, recurrence is also influenced by the interaction that occurs during screening and examinations, i.e. recurrence diminishes once an initial diagnosis has been made. Finally, a key factor in being able to identify suitable patients relates to understanding the relative significance of the vasodepression and cardioinhibitory components-the therapy is best suited to patients that have a significant level of both components. It is probably not needed in patients with mainly cardioinhibitory involvement-data from ISSUE 2 and ISSUE 3 studies suggest that this is a relatively large proportion, particularly with asystolic involvement. The challenge remains in having suitable screening tests to identify the best patients. Tilt table testing has questions concerning its ability to replicate clinical syncope-implantable loop recorders (ILRs) may provide more accurate data but their usage is not yet widely accepted given the costs and invasive nature of the monitor.

Head Immobilization can Impair Jaw Function

Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandibular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.

Assessment of psoriatic plaque in vivo with correlation mapping optical coherence tomography

BACKGROUND/PURPOSE

Vascular abnormalities play an acute role in the pathogenesis of psoriasis. In order to characterize vascular involvement in psoriasis and its regular clinical assessment in vivo, non-invasive high speed imaging with high resolution and high sensitivity is needed.

METHODS

The correlation mapping optical coherence tomography (cmOCT) technique was used for in vivo microcirculation imaging of human forearm under normal and psoriatic conditions. The cmOCT technique developed by our group uses dense scanning OCT image acquisition and post-processing software based on correlation statistics. The frequency domain OCT system was used for imaging which acquires a 3D volume of 1024 × 1024 A-scans, each of 512 pixels deep in approximately 70 s. The cmOCT technique processes the resulting OCT volume within 116 s using a 7 × 7 kernel.

RESULTS

3D structural and functional (microcirculation) maps of the healthy tissue and the psoriatic plaque were obtained using the cmOCT technique. The presented results indicate that cmOCT allows not only the identification of the microvessels, but also produces more detailed microvascular networks showing how the blood vessels relate to each other in healthy tissue and within the plaque. The microcirculation pattern within the plaque is totally different from the healthy tissue. The distinct changes are also observed in vessel density, tortuosity, and orientation.

CONCLUSION

The cmOCT provides high sensitivity and imaging speed for in vivo microcirculation imaging within the human skin under normal and diseased conditions.

Comparison of small bowel follow through and abdominal CT for detecting recurrent Crohn's disease in neoterminal ileum

PURPOSE

To assess the findings of recurrent Crohn's disease in the neoterminal ileum on small bowel follow through (SBFT) and computed tomography (CT) as well as the overall diagnostic performance of these imaging tests.

METHODS

Our radiology database yielded 52 patients with an ileocolic anastomosis for Crohn's disease who underwent SBFT and CT. The images were reviewed to determine the sensitivity, specificity, PPV, and NPV for individual findings of recurrent Crohn's disease in the neoterminal ileum. The overall sensitivity, specificity, PPV, and NPV of these tests for recurrent Crohn's disease were determined by comparing imaging reports to endoscopic and surgical findings in 45 patients (87%) and clinical response to treatment in seven (13%).

RESULTS

SBFT had a sensitivity of 90%, specificity of 85%, PPV of 95%, and NPV of 73% for detecting recurrent Crohn's disease, and CT had a sensitivity of 77%, specificity of 69%, PPV of 88%, and NPV of 50%. These tests combined had a sensitivity of 95%, specificity of 69%, PPV of 90%, and NPV of 82%. The most common findings were luminal narrowing, thickened folds, and ulcers (especially aphthoid lesions) on SBFT and bowel wall thickening on CT. CT also revealed extraenteric collections not visualized on SBFT in three patients (8%).

CONCLUSIONS

Our experience suggests that SBFT is more sensitive and specific than CT for detecting recurrent Crohn's disease in the neoterminal ileum, mainly because of the ability of barium studies to depict aphthoid lesions not visualized on CT. Conversely, CT is better for detecting extraenteric findings such as abscesses. When combined, these tests have a higher sensitivity for detecting recurrent Crohn's disease than either test alone.

Outcome of selective non-operative management of penetrating abdominal injuries from the North American National Trauma Database

BACKGROUND

The aim of this study was to investigate trends in the practice of selective non-operative management (SNOM) for penetrating abdominal injury (PAI) and to determine factors associated with its failure.

METHODS

The National Trauma Data Bank for 2002-2008 was reviewed. Patients with PAI were categorized as those who underwent successful SNOM (operative management not required) and those who failed SNOM (surgery required more than 4 h after admission). Yearly rates of SNOM versus non-therapeutic laparotomy (NTL) were plotted. Multivariable regression analysis was performed to identify factors associated with failed SNOM and mortality.

RESULTS

A total of 12 707 patients with abdominal gunshot and 13 030 with stab wounds were identified. Rates of SNOM were 22.2 per cent for gunshot and 33.9 per cent for stab wounds, and increased with time (P < 0.001). There was a strong correlation between the rise in SNOM and the decline in NTL (r = - 0.70). SNOM failed in 20.8 and 15.2 per cent of patients with gunshot and stab wounds respectively. Factors predicting failure included the need for blood transfusion (odds ratio (OR) 1.96, 95 per cent confidence interval 1.11 to 3.46) and a higher injury score. Failed SNOM was independently associated with mortality in both the gunshot (OR 4.48, 2.07 to 9.70) and stab (OR 9.83, 3.44 to 28.00) wound groups.

CONCLUSION

The practice of SNOM is increasing, with an associated decrease in the rate of NTL for PAI. In most instances SNOM is successful; however, its failure is associated with increased mortality. Careful patient selection and adherence to protocols designed to decrease the failure rate of SNOM are recommended.

Disturbed jaw behavior in whiplash-associated disorders during rhythmic jaw movements

As shown previously, "functional jaw movements" are the result of coordinated activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital, and cervical spine joints. In this study, the effect of neck trauma on natural jaw function was evaluated in 12 individuals suffering from whiplash-associated disorders (WAD). Spatiotemporal characteristics of mandibular and concomitant head movements were evaluated for three different modes of rhythmic jaw activities: self-paced continuous maximal jaw-opening/-closing movements, paced continuous maximal jaw-opening/-closing movements at 50 cycles/minute, and unilateral chewing. Compared with healthy subjects, the WAD group showed smaller magnitude and altered coordination pattern (a change in temporal relations) of mandibular and head movements. In conclusion, these results show that neck trauma can derange integrated jaw and neck behavior, and underline the functional coupling between the jaw and head-neck motor systems.

Spatiotemporal consistency of human mandibular and head-neck movement trajectories during jaw opening-closing tasks

Previous studies of spatial and temporal coordination between human mandibular and head-neck movements during single as well as rhythmic jaw opening-closing tasks suggest that these movements are regulated by central nervous commands common for jaw and neck muscles. The present study evaluated the spatiotemporal consistency of concomitant mandibular and head-neck movements during repeated single jaw opening-closing tasks, in short- as well as long-term perspectives and at different speeds. The subjects were seated in an upright position without head support. They were instructed to perform single maximal jaw opening-closing movements, repeated ten times for fast and slow speed, respectively. Recordings were made at two sessions. A wireless optoelectronic technique was used to record three-dimensional mandibular and head-neck movements. The spatiotemporal consistency of repeated movement trajectories of the mandible (both in relation to the head and in space) and of the head-neck was quantitatively assessed by a spatiotemporal index (STI). In addition, mean movement trajectory patterns were compared for speed and recording sessions (expressed as correlation coefficient, r). The results showed relatively small STI (high degree of spatiotemporal consistency) and high r (reproducible trajectory patterns) values, both in short- and long-term perspectives, for concomitant mandibular and head-neck movements. The data were not generally speed related. In conclusion, the present results suggest a high degree of spatiotemporal consistency of the kinematic patterns of mandibular and head-neck movements during jaw opening-closing, in short- as well as long-term perspectives. They also indicate that underlying neural processes are invariant in nature. The results give further support to the notion of a tight functional coupling between the human jaw and the neck motor systems during natural jaw function.

Registry based trauma outcome: perspective of a developing country

OBJECTIVE

To report trauma outcome from a developing country based on the Trauma and Injury Severity Scoring (TRISS) method and compare the outcome with the registry data from Major Trauma Outcome Study (MTOS).

DESIGN

Registry based audit of all trauma patients over two years.

SETTING

Emergency room of a teaching university hospital.

SUBJECTS

279 injured patients meeting trauma team activation criteria including all deaths in the emergency room.

OUTCOME MEASURES

TRISS methodology to compare expected and observed outcome.

STATISTICAL ANALYSIS

W, M, and Z statistics and comparison with MTOS data.

RESULTS

279 patients meeting the trauma triage criteria presented to the emergency room, 235 (84.2%) were men and 44 (15.8%) women. Blunt injury accounted for 204 (73.1%) and penetrating for 75 (26.9%) patients. Seventy two patients had injury severity score of more than 15. Only 18 (6.4%) patients were transported in an ambulance. A total of 142 (50.9%) patients were transferred from other hospitals with a mean prehospital delay of 7.1 hours. M statistic of our study subset was 0.97, indicating a good match between our patients and MTOS cohort. There were 18 deaths with only one unexpected survivor. The expected number of deaths based on MTOS dataset should have been 12.

CONCLUSIONS

Present injury severity instruments using MTOS coefficients do not accurately correlate with observed survival rates in a developing country.

Integrated jaw and neck function in man. Studies of mandibular and head-neck movements during jaw opening-closing tasks

This investigation was undertaken to test the hypothesis of a functional relationship between the human temporomandibular and craniocervical regions. Mandibular and head-neck movements were simultaneously recorded in healthy young adults using a wireless optoelectronic system for three dimensional movement recording. The subjects were seated in an upright position without head support and were instructed to perform maximal jaw opening-closing movements at fast and slow speed. As a basis, a study was undertaken to develop a method for recording and analysis of mandibular and head-neck movements during natural jaw function. A consistent finding was parallel and coordinated head-neck movements during both fast and slow jaw opening-closing movements. The head in general started to move simultaneously with or before the mandible at the initiation of jaw opening. Most often, the head attained maximum velocity after the mandible. A high degree of spatiotemporal consistency of mandibular and head-neck movement trajectories was found in successive recording sessions. The head movement amplitude and the temporal coordination between mandibular and head-neck movements were speed related but not the movement trajectory patterns. Examination of individuals suffering from temporomandibular disorders and whiplash associated disorders (WAD) showed, compared with healthy subjects, smaller amplitudes, a diverse pattern of temporal coordination but a similar high degree of spatiotemporal consistency for mandibular and head-neck movements. In conclusion, the results suggest the following: A functional linkage exists between the human temporomandibular and craniocervical regions. Head movements are an integral part of natural jaw opening-closing. "Functional jaw movements" comprise concomitant mandibular and head-neck movements which involve the temporomandibular, the atlanto-occipital and the cervical spine joints, caused by jointly activated jaw and neck muscles. Jaw and neck muscle actions are elicited and synchronised by neural commands in common for both the jaw and the neck motor systems. These commands are preprogrammed, particularly at fast speed. In the light of previous observations of concurrent jaw and head movements during foetal yawning, it is suggested that these motor programs are innate. Neural processes underlying integrated jaw and neck function are invariant both in short- and long-term perspectives. Integrated jaw and neck function seems to be crucial for maintaining optimal orientation of the gape in natural jaw function. Injury to the head-neck, leading to WAD may derange integrated jaw-neck motor control and compromise natural jaw function.

Temporal coordination between mandibular and head-neck movements during jaw opening-closing tasks in man

Previous finding of concomitant mandibular and head movements during jaw function suggest a functional relation between the human jaw and neck regions. This study examined the temporal coordination between mandibular and head-neck movements during maximal jaw opening-closing tasks, at fast and slow speed. Twenty-four healthy individuals, median age 25 years, participated in the study. They were seated with firm back support but without head-neck support. Mandibular and head movements were simultaneously monitored by a wireless optoelectronic system for three-dimensional movement recording. The timing of head movement in relation to mandibular movement was estimated at defined time-points (start, peak, end and maximum velocity of movement), and during the entire course of the jaw-opening and jaw-closing phases. The results showed that the head in general started to move simultaneously with or before the mandible, reached the peak position simultaneously with, before or after the mandible, and reached the end position after the mandible. A higher degree of temporal coordination was found for fast speed at the start and the peak positions. The head most often attained maximum velocity after the mandible, and mostly lagged behind the mandible during the entire jaw-opening and -closing phases. These findings support the notion of a functional linkage between the human temporomandibular and craniocervical regions. They suggest that "functional jaw movements" comprise concomitant mandibular and head-neck movements which involve the temporomandibular, the atlanto-occipital and the cervical spine joints, and are caused by jointly activated jaw and neck muscles. It is proposed that these jaw and neck muscle actions, particularly at fast speed, are elicited and synchronized by preprogrammed neural command(s) common to both the jaw and the neck motor systems. From the present results and previous observations of concurrent jaw and head movement during fetal yawning, we suggest that these motor programmes are innate.

Co-ordinated mandibular and head-neck movements during rhythmic jaw activities in man

Recent observations in man of concomitant mandibular and head movements during single maximal jaw-opening/-closing tasks suggest a close functional relationship between the mandibular and the head-neck motor systems. This study was aimed at further testing of the hypothesis of a functional integration between the human jaw and neck regions. Spatiotemporal characteristics of mandibular and associated head movements were evaluated for 3 different modes of rhythmic jaw activities: self-paced continuous maximal jaw-opening/-closing movements, paced continuous maximal jaw-opening/-closing movements at 50 cycles/minute, and unilateral chewing. Mandibular and head-neck movements were simultaneously recorded in 12 healthy young adults, by means of a wireless opto-electronic system for 3-D movement recordings, with retro-reflective markers attached to the lower (mandible) and upper (head) incisors. The results showed that rhythmic mandibular movements were paralleled by head movements. An initial change in head position (head extension) was seen at the start of the first jaw-movement cycle, and this adjusted head position was retained during the following cycles. In addition to this prevailing head extension, the maximal jaw-opening/-closing cycles were paralleled by head extension-flexion movements, and in general the start of these head movements preceded the start of the mandibular movements. The results support the idea of a functional relationship between the temporomandibular and the cranio-cervical neuromuscular systems. We therefore suggest a new concept for human jaw function, in which "functional jaw movements" are the result of activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital, and cervical spine joints.

Wireless optoelectronic recordings of mandibular and associated head-neck movements in man: a methodological study

Human mandibular movements in space are the result of combined motions of the mandible and the head-neck. They can be simultaneously monitored by an optoelectronic recording technique via markers at different locations on the mandible and on the head. Markers can be attached to the teeth or to the facial skin. Mandibular movements relative to the head can be calculated by one- or three-dimensional (1D and 3D, respectively) mathematical compensation for head movements. The present study analysed mandibular and associated head movements during maximal jaw opening-closing tasks in 10 healthy subjects using a wireless 3D optoelectronic movement recording system. The study aimed to: (i) estimate the soft tissue related displacement of skin-attached markers at different locations on the face; (ii) compare 1D with 3D mathematical compensation for associated head movements; (iii) evaluate the influence of marker location on the recorded head and mandibular movement amplitudes; and (iv) compare skin-attached markers with teeth-attached markers with regard to temporal estimates of recorded mandibular and head movements. Markers were attached to the upper and lower incisors and to the skin of the forehead, nose-bridge, nose-tip and chin. Soft tissue related displacement of skin-attached markers varied between locations. The displacement for the chin marker was larger than that of other markers. The least displacement was found for the nose-bridge marker. However, relative to mandibular and head movements, respectively, the displacement of the chin marker was of the same order as that of the nose-bridge marker. The temporal estimates were not significantly affected by displacement of the skin-attached markers. Markers at different locations on the head and the mandible registered different amplitudes. The mandibular movement patterns calculated by 1D and 3D compensation were not comparable. It is concluded that markers attached to the chin and the nose-bridge can be reliably used in temporal analyses of mandibular and head movements during maximal jaw opening-closing. With certain limitations, they are acceptable for spatial analyses. Selection of method of marker attachment, marker location, and method of compensation for associated head movements should be based on the aim of the study.

Fetal alcohol exposure alters serotonin transporter sites in rat brain

This study examined the effects of fetal alcohol exposure (FAE) on serotonin transporter (5-HTT) binding sites in the brains of developing male and female rat offspring using the technique of quantitative autoradiography. Time-pregnant dams were fed liquid ethanol diet, isocaloric diet without ethanol or normal rat chow. Male and female offspring were sacrificed at 21, 40 and 60 days of age, brains removed and sectioned for analysis of 5-HTT sites. FAE led to distinct effects on 5-HTT sites depending on the age and gender of the offspring. FAE increased 5-HTT binding sites in cortical layers 5, 6, hippocampal layers CA(2,3), lateral nucleus of the amygdala and in the dorsal raphe nucleus. FAE decreased 5-HTT binding sites in the medial nucleus of amygdala, dorsomedial and ventromedial nuclei of the hypothalamus. FAE decreased 5-HTT binding sites temporarily in the ventromedial nucleus of the hypothalamus in the 21-day-old female; this effect was found to disappear by day 40. In contrast, FAE increased 5-HTT sites in the lateral nucleus of the amygdala in the adult animal, suggesting that ethanol exposure in utero may alter serotonin neurotransmission in discrete brain regions permanently.

Concomitant mandibular and head-neck movements during jaw opening-closing in man

To test the hypothesis of a functional relationship between the human mandibular and cranio-cervical motor systems, head-neck movements during voluntary mandibular movements were studied in 10 healthy young adults, using a wireless optoelectronic system for three-dimensional (3D) movement recording. The subjects, unaware of the underlying aim of the study, were instructed to perform maximal jaw opening-closing tasks at fast and slow speed. Movements were quantified as 3D movement amplitudes. A consistent finding in all subjects was parallel and coordinated head-neck movements during both fast and slow jaw opening-closing tasks. Jaw opening was always accompanied by head-neck extension and jaw closing by head-neck flexion. Combined movement and electromyographic recordings showed concomitant neck muscle activity during head-neck movements, indicative of an active repositioning of the head. No differences in 3D movement amplitudes could be seen with respect to speed. The head movement was 50% of the mandibular movement during jaw opening, but significantly smaller (30-40%), during the jaw closing phase. In repeated tests, the 3D movement amplitudes of the concomitant head movements were less variable during slow jaw movement and during the jaw opening phase, than during fast and jaw closing movements, suggesting speed- and phase-related differences in the mechanisms controlling the integrated mandibular and head-neck motor acts. The present results give further support to the concept of a functional trigeminocervical coupling during jaw activities in man.

Evaluation of skin- versus teeth-attached markers in wireless optoelectronic recordings of chewing movements in man

This study evaluated the applicability of skin- and teeth-attached reflex markers fixed to the mandible and the head for optoelectronic recording of chewing movements. Markers were attached to the upper and lower incisors and to the skin on the forehead, the bridge of the nose, the tip of the nose and the chin in seven subjects. Chewing movements were recorded in three dimensions using a high-resolution system for wireless optoelectronic recording. Skin markers were systematically displaced due to skin stretch. The largest displacement was observed for the chin marker, whereas minor displacement was found for markers located on the forehead and the bridge of the nose. In repeated recordings, the smallest intra-individual variation in displacement was found for the marker on the bridge of the nose. In spite of relatively large displacement for the chin marker, the temporal estimates of the mandibular movement were not affected. Teeth markers were found to significantly increase the vertical mouth opening, although the duration of the chewing cycle was unaffected. This indicates an increase in chewing velocity. We suggest that markers located on the bridge of the nose are acceptable for recordings of chewing movements. Skin markers on the chin can be reliably used for temporal analysis. They are also acceptable for spatial analysis if an intra-individual variability of 2 mm is allowed. Teeth-attached markers may significantly influence the natural chewing behavior. Thus, both types of marker systems have advantages as well as disadvantages with regard to the accuracy of the chewing movement analysis. Selection of a marker system should be based on the aims of the study.

Hypomagnesaemia in postoperative patients: an important contributing factor in postoperative mortality

Magnesium is the second most abundant intracellular cation and the fourth most abundant cation in the body. Clinical manifestations of hypomagnesaemia include neuromusclar, neurological, psychiatric and cardiac arrhythmias including torsade de pointes resulting in sudden death. Incidence of hypomagnesaemia in hospitalised patients in common and there is a lack of clinical awareness. Clinicians should become familiar with the common conditions and therapeutics that are risk factors for underlying hypomagnesaemia and become familiar with magnesium replacement regimens. Two patients who suffered fatal complications in whom hypomagnesaemia was an important contributing factor are presented. Hypokalaemia and hypocalcaemia are common in severe magnesium deficiency and require concurrent monitoring and correcting.

Bradykinin-induced venodilation is not different in blacks

AIMS

The aim of this study was to determine whether young, normotensive blacks who have been recently demonstrated to have a venodilator response to isoprenaline decreased compared with whites, also have an decreased vasodilatory response to bradykinin.

METHODS

Eleven black and 11 white subjects were studied. Full dose-response curves to bradykinin (dosing range 0.5-500 ng min-1) were generated in hand veins preconstricted with phenylephrine (dosing range 20-6800 ng min-1).

RESULTS

The groups had a similar maximal response to bradykinin (57.6 +/- 32.2% vs 67.8 +/- 49.3%, P = NS 95% confidence interval for the difference (CI): -47.3, 26.8). Also, the log of the dose that produced half maximal response to bradykinin was similar for the two groups (0.89 +/- 0.58 vs 0.78 +/- 0.61 ng min-1, P = NS, 95% CI: -0.42, 0.64). There was no difference between the two groups in the log dose of phenylephrine necessary to produce 80% constriction of the hand vein.

CONCLUSION

Diminished vasodilatory response to endothelium-derived relaxing factor (EDRF) does not seem to be associated with the increased prevalence of hypertension in blacks.

Acute complications of cocaine intoxication

The advent of crack cocaine has changed the face of acute cocaine intoxication. Repeated doses of highly concentrated, rapidly delivered drug can give rise to an array of potentially fatal cardiovascular, neurologic, and respiratory complications.

Impaired beta 2-adrenergic agonist-induced venodilation in Indians of Asian origin

OBJECTIVES

Vascular responsiveness to infusions of vasoactive substances varies between ethnic groups. Indians of Asian origin are a rapidly growing ethnic group in the United States but have not been extensively studied. We sought to determine whether there was any difference in venous responsiveness to a local infusion of vasoactive substances between Indians of Asian origin and white subjects.

METHODS

We used the dorsal hand vein compliance technique to construct full dose-response curves to the beta 2-agonist isoproterenol (2 to 270 ng/min) in hand veins preconstricted with phenylephrine in 11 young white subjects and in 11 young Asian Indian subjects. In addition, six subjects in each group were randomly selected to have full dose-response curves to nitroglycerin (0.006 to 1485 ng/min) generated.

RESULTS

The maximal response (E(max)) to isoproterenol was smaller in Asian Indians (33.9% +/- 41.1% in Asian Indians versus 107.0% +/- 60.1% in white subjects; p < 0.01). There was no difference in the log of the dose that produced half-maximal venodilation [log(ED50)] between the two groups (1.10 +/- 0.57 in Asian Indians versus 1.15 +/- 0.50 in white subjects). However, nitroglycerin infusion produced similar responses for both the E(max) and the log(ED50) between the two groups.

CONCLUSION

These results indicate that differences may exist in beta-adrenergic responsiveness among white subjects and Indians of Asian origin. Therapy for diseases that use beta-adrenergic responses, such as hypertension, must take into account these differential vascular responses because they may affect their efficacy in Asian Indians.

Spatial activation maps--bioelectric signals related to 3D recorded movements

The analysis of multidimensional neurophysiological data poses difficulties for the scientist in understanding the often complex inherent data relations. This is particularly the case when neuromuscular cell discharge parameters are to be related to body segment movement characteristics in freely behaving animals or humans. The understanding of such data is greatly simplified if the recorded data can be visualized in an adequate way, and relevant data relations are thus highlighted. This report describes a rationale for display and qualitative analyses of muscle discharge patterns in relation to three-dimensionally recorded limb or body movements. The method is illustrated by creating spatial activation plots and spatial activation maps of the electromyographic activity in the first interosseal muscle in the human hand, but this rationale for data presentation can be applied to most excitable tissues that are activated in relation to body or limb movements.