Neck muscles in the rhesus monkey. II. Electromyographic patterns of activation underlying postures and movements

Electromyographic (EMG) activity was recorded in < or = 12 neck muscles in four alert monkeys whose heads were unrestrained to describe the spatial and temporal patterns of neck muscle activation accompanying a large range of head postures and movements. Some head postures and movements were elicited by training animals to generate gaze shifts to visual targets. Other spontaneous head movements were made during orienting, tracking, feeding, expressive, and head-shaking behaviors. These latter movements exhibited a wider range of kinematic patterns. Stable postures and small head movements of only a few degrees were associated with activation of a small number of muscles in a reproducible synergy. Additional muscles were recruited for more eccentric postures and larger movements. For head movements during trained gaze shifts, movement amplitude, velocity, and acceleration were correlated linearly and agonist muscles were recruited without antagonist muscles. Complex sequences of reciprocal bursts in agonist and antagonist muscles were observed during very brisk movements. Turning movements of similar amplitudes that began from different initial head positions were associated with systematic variations in the activities of different muscles and in the relative timings of these activities. Unique recruitment synergies were observed during feeding and head-shaking behaviors. Our results emphasize that the recruitment of a given muscle was generally ordered and consistent but that strategies for coordination among various neck muscles were often complex and appeared to depend on the specifics of musculoskeletal architecture, posture, and movement kinematics that differ substantially among species.     

Electromyographic activity of dorsal neck muscles in squirrel monkeys during rotations in an upright or upside down posture

Electromyographic (EMG) activity was recorded from occipitoscapularis, semispinalis, and splenius neck muscles in five alert squirrel monkeys during 0.25-Hz rotations about horizontal axes oriented at 22.5 degrees intervals, including pitch, roll, and intermediate axes. The animals were oriented in either upright or upside down posture. In the upright posture, all monkeys exhibited compensatory EMG activity with maximal activation during rotations about axes between pitch in the pitch forward direction and contralaterally directed roll. Response timing varied across animals with EMG peaks ranging from near pitch forward head velocity to near pitch forward head position. When the head was upside down, response dynamics and directionality were altered to varying degrees in different monkeys. The greatest change in response to head inversion was seen in the monkey that had response phases closest to head position, the least in the animal with phases closest to head velocity. The monkey with EMG response peaks closest to position phase showed nearly 180 degrees inversion of responses when the head was upside down, suggesting that in this monkey a righting reflex mediated by utricular signals was activated in the upside down posture. The monkey with EMG response peaks closest to velocity phase may have lacked a righting response and exhibited only a canal-mediated compensatory vestibulocervical reflex in both upright and upside down postures. The results suggest that reflex contraction of neck muscles in response to passive head rotation includes an interplay of compensatory and righting responses that varies from animal to animal.     

Response of vestibular neurons to head rotations in vertical planes. II. Response to neck stimulation and vestibular-neck interaction

1. We have studied the responses of neurons in the lateral and descending vestibular nuclei of decerebrate cats to stimulation of neck receptors, produced by rotating the body in vertical planes with the head stationary. The responses to such neck stimulation were compared with the responses to vestibular stimulation produced by whole-body tilt, described in the preceding paper. 2. After determining the optimal vertical plane of neck rotation (response vector orientation), the dynamics of the neck response were studied over a frequency range of 0.02-1 Hz. The majority of the neurons were excited by neck rotations that brought the chin toward the ipsilateral side; most neurons responded better to roll than to pitch rotations. The typical neck response showed a low-frequency phase lead of 30 degrees, increasing to 60 degrees at higher frequencies, and a gain that increased about threefold per decade. 3. Neck input was found in about one-half of the vestibular-responsive neurons tested with vertical rotations. The presence of a neck response was correlated with the predominant vestibular input to these neurons; neck input was most prevalent on neurons with vestibular vector orientations near roll and receiving convergent vestibular input, either input from both ipsilateral vertical semicircular canals, or from canals plus the otolith organs. 4. Neurons with both vestibular and neck responses tend to have the respective orientation vectors pointing in opposite directions, i.e., a head tilt that produces an excitatory vestibular response would produce an inhibitory neck response. In addition, the gain components of these responses were similar. These results suggest that during head movements on a stationary body, these opposing neck and vestibular inputs will cancel each other. 5. Cancellation was observed in 12 out of 27 neurons tested with head rotation in the mid-frequency range. For most of the remaining neurons, the response to such a combined stimulus was greatly attenuated: the vestibular and neck interaction was largely antagonistic. 6. Neck response dynamics were similar to those of the vestibular input in many neurons, permitting cancellation to take place over a wide range of stimulus frequencies. Another pattern of interaction, observed in some neurons with canal input, produced responses to head rotation that had a relatively constant gain and remained in phase with position over the entire frequency range; such neurons possibly code head position in space.     

William Hunter's casts of the gravid uterus at the University of Glasgow

The Hunterian Collection at the University of Glasgow possesses 11 plaster casts showing the pregnant uterus. Three correspond to Plates I, IV, and VI of Hunter's The Anatomy of the Gravid Uterus Exhibited in Figures (1774), progressive stages of dissection of the same specimen. A further three casts show consecutive stages of dissection of a uterus containing a fetus presenting by the breech. The other specimens show a normal pregnancy at about 6 months, a normal full-term uterus with the fetal head becoming engaged, a breech presentation with placenta previa and the umbilical cord around the fetal neck, and an obstructed labor with distended bladder and colon. The 10 on display show realistic coloring and are mounted on black wooden stands. An 11th specimen, amateurishly painted, is not on display. The casts differ in their style; some show only the abdomen, pelvis, perineum, and thighs, others show the full torso. They also differ in the amount of detail shown. The first three casts show the cut femur and muscles at the transected ends of the thighs, also shown in some of the plates in the Gravid Uterus. Although these features enhance the artistic impact of both the engravings and the casts, the authors are unconvinced that Hunter deliberately used them to achieve this, as has been claimed.     

Effect of neck posture on patterns of activation of feline neck muscles during horizontal rotation

The electromyographic (EMG) patterns of neck muscles were recorded during whole-body horizontal rotation in head-free, alert cats and head-restrained, decerebrate cats. In some trials the cervical column of the animal was oriented vertically, whereas in others it was oriented more horizontally. In alert cats making head movements that compensated for the motion of the platform, neck muscles with modulated patterns of activity could be divided into a subset whose individual EMG patterns changed significantly when the neck posture was altered (including longissimus capitis, obliquus capitis superior and scalenus anterior) and a subset whose individual EMG patterns were invariant regardless of neck posture (including obliquus capitis inferior, levator scapulae and complexus). In head-restrained, decerebrate cats, electromyograms from all implanted muscles were modulated similarly in phase with the platform position. Changing the orientation of the neck had little effect upon these EMG patterns evoked by the horizontal vestibulocollic reflex. One decerebrate cat with strong extensor tone was tested further under head-free conditions. There was very little compensatory head movement, but individual neck muscles displayed patterns of activity that were more similar to those observed in alert, head-free animals.     

Neck muscle responses to stimulation of monkey superior colliculus. II. Gaze shift initiation and volitional head movements

We report neck muscle activity and head movements evoked by electrical stimulation of the superior colliculus (SC) in head-unrestrained monkeys. Recording neck electromyography (EMG) circumvents complications arising from the head's inertia and the kinetics of muscle force generation and allows precise assessment of the neuromuscular drive to the head plant. This study served two main purposes. First, we sought to test the predictions made in the companion paper of a parallel drive from the SC onto neck muscles. Low-current, long-duration stimulation evoked both neck EMG responses and head movements either without or prior to gaze shifts, testifying to a SC drive to neck muscles that is independent of gaze-shift initiation. However, gaze-shift initiation was linked to a transient additional EMG response and head acceleration, confirming the presence of a SC drive to neck muscles that is dependent on gaze-shift initiation. We forward a conceptual neural architecture and suggest that this parallel drive provides the oculomotor system with the flexibility to orient the eyes and head independently or together, depending on the behavioral context. Second, we compared the EMG responses evoked by SC stimulation to those that accompanied volitional head movements. We found characteristic features in the underlying pattern of evoked neck EMG that were not observed during volitional head movements in spite of the seemingly natural kinematics of evoked head movements. These features included reciprocal patterning of EMG activity on the agonist and antagonist muscles during stimulation, a poststimulation increase in the activity of antagonist muscles, and synchronously evoked responses on agonist and antagonist muscles regardless of initial horizontal head position. These results demonstrate that the electrically evoked SC drive to the head cannot be considered as a neural replicate of the SC drive during volitional head movements and place important new constraints on the interpretation of electrically evoked head movements.     

The neurophysiological substrate for the cervico-ocular reflex in the squirrel monkey

Passive rotation of the trunk with respect to the head evoked cervico-ocular reflex (COR) eye movements in squirrel monkeys. The amplitude of the reflex varied both within and between animals, but the eye movements were always in the same direction as trunk rotation. In the dark, the COR typically had a gain of 0.3–0.4. When animals fixated earth-stationary targets during low-frequency passive neck rotation or actively tracked moving visual targets with head movements, the COR was suppressed. The COR and vestibulo-ocular reflex (VOR) summed during passive head-on-trunk rotation producing compensatory eye movements whose gain was greater than 1.0. The firing behavior of VOR-related vestibular neurons and cerebellar flocculus Purkinje cells was studied during the COR. Passive neck rotation produced changes in firing rate related to neck position and/or neck velocity in both position-vestibular-pause neurons and eye-head-vestibular neurons, although the latter neurons were much more sensitive to the COR than the former. The neck rotation signals were reduced or reversed in direction when the COR was suppressed. Flocculus Purkinje cells were relatively insensitive to COR eye movements. However, when the COR was suppressed, their firing rate was modulated by neck rotation. These neck rotation signals summed with ocular pursuit signals when the head was used to pursue targets. We suggest that the neural substrate that produces the COR includes central VOR pathways, and that the flocculus plays an important role in suppressing the reflex when it would cause relative movement of a visual target on the retina. Electronic Publication     

Eye-neck coupling during optokinetic responses in head-fixed pigeons (Columba livia): influence of the flying behaviour

The effects of the behavioural context on the properties of slow and fast phases of the horizontal optokinetic nystagmus (OKN) and on the electromyographic neck response (EMG) were investigated in head-fixed pigeons. Responses in two situations were compared: (i) animals were hung in a harness ('resting' condition); (ii) animals in harness were subjected to a frontal airflow that provoked a flight posture ('flying' condition). During optokinetic stimuli the neck muscles responded in synchrony and in synergy with the eye nystagmus in both the 'resting' and the 'flying' conditions. In the 'resting' condition the neck activity was essentially correlated to the slow phase velocity of the eyes (eye SPV) whereas in the 'flying' condition, the neck response was also correlated to the eye position. The neck response was independent of the retinal slip velocity during the OKN. The velocity of the slow and fast phases of the OKN was not modified by flight. However, the 'flying' condition provoked an increase of the neck response by augmenting both its velocity gain (neck EMG/eye SPV) and its position gain (neck EMG/eye position). These results show that although an optokinetic stimulation results in synchronised eye and head motor commands in head-fixed pigeons, only the head motor command is modified by the behavioural context ('flying' vs. 'resting'). This strategy could help pigeons in reorienting their gaze during the flight.     

Head and neck cancer in blacks.

Our experience at University Hospitals of Cleveland (UHOC), Cuyahoga County, Ohio, led us to suspect an increased incidence of head and neck cancer in blacks. We reviewed our tumor registry records from 1975 to 1989 analyzing for age, sex, race, and head and neck site of disease. Head and neck cancers comprised 6.1% of all cancers at UHOC. This is in comparison with 3.7% of all cancers in Cuyahoga County and an estimated 5.5% nationally. This higher proportion of head and neck cancer was observed primarily in black men and women in whom these cancers made up 7.7% of all cancers compared with 5.7% in whites. Both black men and women had a higher percentage of these cancers out of all cancers for their respective sex and race than whites. For all head and neck cancer sites except the salivary glands, blacks were observed to be two to four times more likely than whites to be diagnosed before the age of 50 years (P < .01). These findings thus substantiated an increased incidence and earlier age of onset of head and neck cancers in blacks compared with whites.     

Asymmetric tonic labyrinth reflexes and their interaction with neck reflexes in the decerebrate cat.

1. Tonic labyrinth and neck reflexes were studied separately and in combination in the decerebrate cat with C1 and C2 spinal roots cut. Reflex effects were observed as changes in length of the isotonically loaded medial head of triceps. 2. The tonic labyrinth reflexes acted asymmetrically on the medial head of triceps. Side-down rotation of the head produced shortening in medial triceps, whereas side-up rotations of the head resulted in a lengthening. 3. The tonic neck reflexes acted asymmetrically on the medial head of triceps. Side-down rotations of the neck produced a lengthening of medial triceps, whereas side-up rotations of the neck resulted in shortening. 4. Labyrinth and neck reflexes produce opposite effects on the same limb extensor muscle so that, if the neck innervation is intact, head tilting produces no change in muscle length. 5. It is suggested that the interaction between the labyrinth and neck reflexes contributes to the stability of the trunk, allowing the head to move freely on the body without affecting this stability. Labyrinth and neck reflexes need therefore to be considered together as a single system.     

Detection of EGFR- and HER2-activating mutations in squamous cell carcinoma involving the head and neck.

Recent reports have indicated that mutations in the epidermal growth factor receptor-1 (EGFR) occur in about 7% of patients with squamous cell carcinoma of the head and neck. It is known that many patients with non-small-cell lung cancer who respond to the EGFR inhibitors gefitinib and erlotinib have tumors with EGFR-activating mutations. This might suggest that patients with head and neck squamous carcinoma, who also have tumors with EGFR-activating mutations, might represent a patient population who could benefit from gefitinib or erlotinib therapy. High-resolution melting amplicon analysis (HRMAA) is a recently described technique which can be used for screening tumor DNA isolated from paraffin blocks for tyrosine kinase-activating mutations. In this report we screened 24 cases of squamous cell carcinoma, either primary in the head and neck or secondarily involving the head and neck area, for activating mutations in EGFR exons 18, 19, 20, 21, and for HER2 exons 19 and 20. All cases were followed up by direct DNA sequencing. Two (8%) of the 24 cases were positive. One case was a maxillary sinus tumor which contained an exon 20-activating mutation (N771YinsG). Surprisingly, the other case was a primary squamous cell carcinoma of the skin which invaded the head and neck area only secondarily. This tumor contained an exon 19-activating mutation (G729E). No HER2-activating mutations were found. The presence of a small number of squamous cell carcinomas in the head and neck area with EGFR-activating mutations suggests the existence of a population of patients who could derive benefit from gefitinib or erlotinib therapy. HRMAA could serve as a screening method to easily and rapidly identify these patients.     

Immunological approach in the evaluation of regional lymph nodes of patients with squamous cell carcinoma of the head and neck.

In cancer, regional lymph node (LN) cells are one of the first components of the immune system to have contact with tumor cells or their products. Therefore, the phenotype and functional properties of hematopoietic cells present within the tumor-draining LN are important to understanding their role in the control of malignant cells. Based on the locoregional metastatic behavior of squamous cell carcinoma of the head and neck (SCCH&N) region, we analyzed tumor-draining lymph nodes from SCCH&N patients to obtain insights into regional tumor immunity. Using a three-color fluorescent labeling technique, surface antigen expression was visualized in mononuclear cells of lymph nodes that were obtained from head and neck cancer patients and compared to mononuclear cells of normal lymph nodes. Cell cycle analyses were performed using propidium iodide. Proliferation after phytohemagglutinin stimulation was measured by a sodium tetrazolium-based assay. LN histology was correlated with flow cytometric findings. Regional lymph nodes of head and neck cancer patients undergo morphologic and functional changes. Flow cytometry revealed a decrease in CD8(+) T cells and in some lymph nodes the presence of second or third populations of larger cells with distinct size and granularity that expressed both T (gammadelta/alphabeta) and different natural killer cell markers. Moreover, cell cycle analyses and proliferation assays showed a diminished response to mitogenic stimuli. These changes were found in both metastatic and hyperplastic lymph nodes from head and neck cancer patients; however, no alterations were found in control lymph nodes or peripheral blood mononuclear cells from noncancer patients. The immune alterations detected in lymphocytes present within the draining lymph nodes of head and neck cancer patients may improve our understanding of how tumor cells escape host immunosurveillance. However, this dysfunction in local draining lymph nodes may not be detected systemically.     

Short- and long-term consequences of canal plugging on gaze shifts in the rhesus monkey. I. Effects on gaze stabilization.

Short- and long-term consequences of canal plugging on gaze shifts in the rhesus monkey. I. Effects on gaze stabilization. To study the contribution of the vestibular system to the coordinated eye and head movements of a gaze shift, we plugged the lumens of just the horizontal (n = 2) or all six semicircular canals (n = 1) in monkeys trained to make horizontal head-unrestrained gaze shifts to visual targets. After the initial eye saccade of a gaze shift, normal monkeys exhibit a compensatory eye counterrotation that stabilizes gaze as the head movement continues. This counterrotation, which has a gain (eye velocity/head velocity) near one has been attributed to the vestibuloocular reflex (VOR). One day after horizontal canal plugging, the gain of the passive horizontal VOR at frequencies between 0.1 and 1.0 Hz was <0.10 in the horizontal-canal-plugged animals and zero in the all-canal-plugged animal. One day after surgery, counterrotation gain was approximately 0.3 in the animals with horizontal canals plugged and absent in the animal with all canals plugged. As the time after plugging increased, so too did counterrotation gain. In all three animals, counterrotation gain recovered to between 0.56 and 0.75 within 80-100 days. The initial loss of compensatory counterrotation after plugging resulted in a gaze shift that ended long after the eye saccade and just before the end of the head movement. With recovery, the length of time between the end of the eye saccade and the end of the gaze movement decreased. This shortening of the duration of reduced gain counterrotation occurred both because head movements ended sooner and counterrotation gain returned to 1.0 more rapidly relative to the end of the eye saccade. Eye counterrotation was not due to activation of pursuit eye movements as it persisted when gaze shifts were executed to extinguished targets. Also counterrotation was not due simply to activation of neck receptors because counterrotation persisted after head movements were arrested in midflight. We suggest that the neural signal that is used to cause counterrotation in the absence of vestibular input is an internal copy of the intended head movement.     

Expression of KIT (CD117) in neoplasms of the head and neck: an ancillary marker for adenoid cystic carcinoma.

Adenoid cystic carcinoma is an indolent salivary gland malignancy that is associated with a poor long-term prognosis. The distinction of adenoid cystic carcinoma from other head and neck neoplasms can occasionally be problematic, particularly in small biopsies. Recent studies suggest that KIT (CD117) might be useful as an ancillary marker for adenoid cystic carcinoma; however, the expression of KIT in other benign and malignant head and neck neoplasms, including those that might mimic adenoid cystic carcinoma, has not been well studied. Here we use two different antibodies against KIT to evaluate its expression in a series of 66 adenoid cystic carcinomas compared with its expression in 98 other neoplasms of the head and neck. Overall, 94% (n = 62) of adenoid cystic carcinomas from various anatomic sites and of various histologic subtypes were positive for at least one of the KIT antibodies, and 77% (n = 50) of adenoid cystic carcinoma cases were positive for both antibodies. This contrasted with only 8% (n = 8) of other head and neck neoplasms that were positive for both KIT antibodies (P <.001). It was of note that certain neoplasms, including pleomorphic adenoma, basal cell adenoma, polymorphous low-grade adenocarcinoma, and basal cell carcinoma, that can show histologic overlap with adenoid cystic carcinoma had significantly less KIT immunoreactivity than did adenoid cystic carcinoma (P <.001). In contrast, KIT expression did not reliably distinguish adenoid cystic carcinoma from basal cell adenocarcinoma and basaloid squamous carcinoma (P >.05). The overall sensitivity of the two KIT antibodies for adenoid cystic carcinoma was 82-89%, and the specificity was 87-88%. The findings in this study support the potential use of KIT immunoexpression for distinguishing adenoid cystic carcinoma from many other benign and malignant head and neck neoplasms.     

Capillary structure in elastase-induced emphysema.

The essential component of pulmonary emphysema is destruction of alveoli. Because capillaries make up much of the alveolar wall, it has been a long-held opinion that capillary loss in this disease parallels the loss of other elements of the alveolar septum. Yet the nature of the damage to capillaries and the occurrence of microvascular remodeling are unknown. Scanning electron microscopy of vascular casts of lungs from rats given intratracheal elastase were studied for identifying capillary changes in this type of experimental emphysema. The pressure-volume curves showed a clear distinction between the elastase and saline control animals, and light microscopy showed alveolar enlargement consistent with mild emphysema. The casts of capillaries in the elastase lungs appeared to have larger alveolar baskets, and capillaries ended abruptly near areas of focally destroyed lung. The elastase animals had more nonconnecting capillary segments on the pleural surface where the emphysema was worse and folds in the capillaries were more pronounced, suggesting weakened alveolar walls. The capillary density was decreased on the pleural surface, although this decrease could have resulted from hyperinflation. No difference in capillary diameters or branching frequency occurred. It appears that in this model of emphysema, decreased elastic recoil occurs before diffuse loss of capillaries.     

Skin dose measurements for head and neck radiotherapy.

The use of immobilization plastic masks in head and neck radiotherapy can partially eliminate skin benefits derived from the utilization of megavoltage photon beams. Filters and blocks between the patient and the accelerator can further increase the skin dose value. In this study, the increase in surface dose due to 2 and 3.2 mm of plastic material utilized for patient immobilization was measured. Then, the effect of blocking trays, wedges, and blocks on skin dose in typical conditions for head and neck irradiation was evaluated. The measurements were obtained with a NE2534 chamber (Markus type) on a perspex phantom for 6 MeV x-rays from an accelerator.     

Changes in head and neck position affect elbow joint position sense

Changes in the position of the head and neck have been shown to introduce a systematic deviation in the end-point error of an upper limb pointing task. Although previous authors have attributed this to alteration of perceived target location, no studies have explored the effect of changes in head and neck position on the perception of limb position. This study investigated whether changes in head and neck position affect a specific component of movement performance, that is, the accuracy of joint position sense (JPS) at the elbow. Elbow JPS was tested with the neck in four positions: neutral, flexion, rotation and combined flexion/rotation. A target angle was presented passively with the neck in neutral, after a rest period; this angle was reproduced actively with the head and neck in one of the test positions. The potential effects of distraction from head movement were controlled for by performing a movement control in which the head and neck were in neutral for the presentation and reproduction of the target angle, but moved into flexion during the rest period. The absolute and variable joint position errors (JPE) were greater when the target angle was reproduced with the neck in the flexion, rotation, and combined flexion/rotation than when the head and neck were in neutral. This study suggests that the reduced accuracy previously seen in pointing tasks with changes in head position may be partly because of errors in the interpretation of arm position.     

Morphometric and histochemical studies of the masticatory muscles in growing white rats following ligation of the right common carotid artery

White Wistar rats served for examinations to the masticatory muscles after ligature of the a. carotis communis dextra on the 42nd d after birth. Gravimetric determinations of the dry substance of the muscles were performed in a total of 229 animals. In 65 animals casts of the vessels in synthetic resin (Kallocryl M) were made and the inside diameters of the blood vessels of the corresponding vascular regions measured. Histological, histochemical and muscle-fibre-morphometric observations of the masticatory muscles were made in 10 animals. Due to processes of adaption the a. carotis communis sinistra with an enlarged cross-section supplied the head with an increased blood volume. However, the anatomical and physiologic conditions of the collateral blood vessels conveying blood to the right side of the head prevented the entry of same share of blood into that side. Obviously there is a causal connection between this circumstance and the reduction in the dry substance of the right-side masticatory muscles. Histologic investigations revealed an increase in the capillaries by 10 percent in the animals operated on. The reduction in the diameters of the muscle fibres on the right side of the head was accompanied by a change in the normal combination of fibre types. 2 out of 5 animals which had been operated on showed a fairly homogeneous distribution of the fibre types in the masticatory muscles. Fibres of type 2 tended to be more vulnerable than fibres of type 1. Pathogenetically, the reduction in the dry substance of muscles and the reduction in the diameters of the muscle fibres are caused by nutritive disturbances in connection with restricted circulation. The neuronal-trophic sphere and the mechanism which is responsible for the differentiation of the muscle-fibre types seem to be affected as well. The myokinetic synapses are not affected.     

T Cells Augment Monocyte and Neutrophil Function in Host Resistance against Oropharyngeal Candidiasis

The purpose of this study was to identify the cell populations involved in recovery from oral infections with Candida albicans. Monoclonal antibodies specific for CD4+ cells, CD8+ cells, and polymorphonuclear leukocytes were used to deplete BALB/c and CBA/CaH mice of the relevant cell populations in systemic circulation. Monocytes were inactivated with the cytotoxic chemical carrageenan. Mice were infected with 10(8) C. albicans yeast cells and monitored for 21 days. Systemic depletion of CD4+ and CD8+ T lymphocytes alone did not increase the severity of oral infection compared to that of controls. Oral colonization persisted in animals treated with head and neck irradiation and depleted of CD4+ T cells, whereas infections in animals that received head and neck irradiation alone or irradiation and anti-CD8 antibody cleared the infection in a comparable fashion. The depletion of polymorphonuclear cells and the cytotoxic inactivation of mononuclear phagocytes significantly increased the severity of oral infection in both BALB/c and CBA/CaH mice. High levels of interleukin 12 (IL-12) and gamma interferon (IFN-gamma) were produced by lymphocytes from the draining lymph nodes of recovering animals, whereas IL-6, tumor necrosis factor alpha, and IFN-gamma were detected in the oral mucosae of both na?ve and infected mice. The results indicate that recovery from oropharyngeal candidiasis in this model is dependent on CD4+-T-cell augmentation of monocyte and neutrophil functions exerted by Th1-type cytokines such as IL-12 and IFN-gamma.     

Amide proton transfer‐weighted imaging of the head and neck at 3 T: a feasibility study on healthy human subjects and patients with head and neck cancer

The aim of this study was to explore the feasibility and repeatability of amide proton transfer‐weighted (APTw) MRI for the head and neck on clinical MRI scanners. Six healthy volunteers and four patients with head and neck tumors underwent APTw MRI scanning at 3 T. The APTw signal was quantified by the asymmetric magnetization transfer ratio (MTR_asym) at 3.5 ppm. Z spectra of normal tissues in the head and neck (masseter muscle, parotid glands, submandibular glands and thyroid glands) were analyzed in healthy volunteers. Inter‐scan repeatability of APTw MRI was evaluated in six healthy volunteers. Z spectra of patients with head and neck tumors were produced and APTw signals in these tumors were analyzed. APTw MRI scanning was successful for all 10 subjects. The parotid glands showed the highest APTw signal (~7.6% average), whereas the APTw signals in other tissues were relatively moderate. The repeatability of APTw signals from the masseter muscle, parotid gland, submandibular gland and thyroid gland of healthy volunteers was established. Four head and neck tumors showed positive mean APTw ranging from 1.2% to 3.2%, distinguishable from surrounding normal tissues. APTw MRI was feasible for use in the head and neck regions at 3 T. The preliminary results on patients with head and neck tumors indicated the potential of APTw MRI for clinical applications. Copyright © 2014 John Wiley & Sons, Ltd.