Functional connectivity of human chewing: an fcMRI study.

Mastication is one of the most important orofacial functions. The neurobiological mechanisms of masticatory control have been investigated in animal models, but less so in humans. This project used functional connectivity magnetic resonance imaging (fcMRI) to assess the positive temporal correlations among activated brain areas during a gum-chewing task. Twenty-nine healthy young-adults underwent an fcMRI scanning protocol while they chewed gum. Seed-based fcMRI analyses were performed with the motor cortex and cerebellum as regions of interest. Both left and right motor cortices were reciprocally functionally connected and functionally connected with the post-central gyrus, cerebellum, cingulate cortex, and precuneus. The cerebellar seeds showed functional connections with the contralateral cerebellar hemispheres, bilateral sensorimotor cortices, left superior temporal gyrus, and left cingulate cortex. These results are the first to identify functional central networks engaged during mastication.

Brain activity and human unilateral chewing: an FMRI study.

Brain mechanisms underlying mastication have been studied in non-human mammals but less so in humans. We used functional magnetic resonance imaging (fMRI) to evaluate brain activity in humans during gum chewing. Chewing was associated with activations in the cerebellum, motor cortex and caudate, cingulate, and brainstem. We also divided the 25-second chew-blocks into 5 segments of equal 5-second durations and evaluated activations within and between each of the 5 segments. This analysis revealed activation clusters unique to the initial segment, which may indicate brain regions involved with initiating chewing. Several clusters were uniquely activated during the last segment as well, which may represent brain regions involved with anticipatory or motor events associated with the end of the chew-block. In conclusion, this study provided evidence for specific brain areas associated with chewing in humans and demonstrated that brain activation patterns may dynamically change over the course of chewing sequences.

Housing placement and subsequent days homeless among formerly homeless adults with mental illness.

OBJECTIVE: The study examined the influence of group or individual housing placement and consumer characteristics on the number of days subsequently homeless among formerly homeless mentally ill persons. METHODS: A total of 303 homeless shelter residents with severe mental illness were screened for dangerousness, 118 were randomly assigned to either independent apartment or staffed group living sites, and 110 were followed for 18 months. Study participants' sociodemographic characteristics, diagnosis, and residential preferences and the residential recommendations made by clinicians were measured at baseline. RESULTS: Overall, 76 percent of the study participants were housed at the end of the 18-month follow-up period, although 27 percent had experienced at least one episode of homelessness during the period. The number of days homeless was greater for individuals assigned to independent apartments than for those placed in staffed group homes, but only for members of minority groups. Substance abuse was the strongest individual-level predictor of days homeless. Individuals whom clinicians identified as needing group living experienced more days homeless, irrespective of the type of housing they received. Consumers who stated a strong preference for independent living had more days homeless than those who were amenable to staffed group homes. CONCLUSIONS: Although consumers more frequently prefer independent living, placement in staffed group housing resulted in somewhat fewer days homeless for some groups of consumers. Further experience of homelessness by formerly homeless mentally ill individuals may be reduced by providing effective substance abuse treatment and by paying special attention to consumers identified by clinicians to be at particular risk for housing loss.

[Animal experiments on the frontal sinus development after craniofacial surgery on the frontal bone in Göttingen miniature pigs]. / Tierexperimentelle Untersuchungen zur Stirnhöhlenentwicklung nach kraniofazialer Austauschplastik des Os frontale beim Göttinger Miniaturschwein.

According to the literature, the development of the frontal sinus is a result of the active immigration of cells from the ethmoidal complex into the os frontale. This migration theory is in contrast to the results in patients with Apert's syndrome. When front-orbital advancement at the age of a few months is performed in these patients--at a time when the frontal suture is not yet closed--a sinus developed despite the distance between nasal root and os frontale, being up to 2 cm. In order to investigate the development of the frontal sinus, an animal study in 12 juvenile Goettingen minipigs (age 5-6 weeks) with histologically pronen un-developed frontal sinus was performed. To exclude the emigration of ethmoidal complex cells into the frontale bone an orthotopical transposition of the frontale bone into the os occipitale was performed. Histologically the development of a frontal sinus in the frontal bone was excluded before transplantation. The macro- and microscopic comparison with a control group revealed that in the orthotopical transplants in the os occipitale an epithelium-lined sinus developed beginning from the 35th week. Based on our histomorphological results, a development scheme for the genesis of the sinus frontalis and a model is drawn.

Neuropsychological function in homeless mentally ill individuals.

Because little data are available on the neuropsychological functioning of severely and persistently mentally ill (SPMI) persons who are homeless, our primary goal was to describe accurately and extensively the general neuropsychological functioning of a large group of such homeless individuals. In addition, we have sought to examine the relationship between some neuropsychological functions and demographic, illness, and clinical state measures in this population. A 5-hour neuropsychological test battery was administered to 116 SPMI homeless individuals. Neuropsychological, diagnostic, substance abuse, clinical, and psychopathology data were obtained in a standardized manner. SPMI homeless individuals were significantly impaired on a wide range of neuropsychological functions. Specific test performances were most significantly related to precursor variables (level of education and parental socioeconomic status) and state variables (level of psychosis and anticholinergic medication dose). Gender and substance abuse had significant effects limited to sustained attention. Neuropsychological performance was impaired in this sample of homeless SPMI persons. Further research, using profile analysis to directly compare groups composed of homeless persons without psychiatric illness or demographically matched persons of comparable psychiatric status who are not homeless will help clarify the role of homelessness and psychosis on neuropsychological function.

Self-report and observer measures of substance abuse among homeless mentally ill persons in the cross-section and over time.

The comparability of self-report and observer measures of substance abuse among 118 homeless mentally ill persons was assessed using cross-sectional and longitudinal measures. Possible correlates of nondisclosure were identified from demographic variables and clinical indicators. Lifetime abuse reported at baseline was a sensitive predictor of subsequent abuse behavior in the project, but cross-sectional measures based only on self-report or observer ratings failed to identify many abusers. A total of 17% of the subjects never disclosed abuse that was observed during the project. The level of substance abuse is likely to be severely underestimated among homeless mentally ill persons when only one self-report measure is used at just one point in time. This problem can, however, largely be-overcome by incorporating information from observers and from multiple follow-ups or by focusing on lifetime rather than current abuse. We also conclude that underreporting may bias estimates of some correlates of substance abuse.

Assessing homeless mentally ill persons for permanent housing: screening for safety.

Although placement in community housing is a frequent intervention with populations of seriously mentally ill homeless individuals, there has been little formal investigation of the criteria used by clinicians in screening individuals for such placement. In this paper, we describe screening a population of 303 homeless people with severe mental illness for placement in independent apartments. We assess subjects' level of risk along multiple dimensions and determine the contribution of each risk dimension to the final safety decision. In addition, we evaluate the validity of the risk measures with other measures of clinical condition. Two-thirds of the sample were judged as safe for independent living. Assaultiveness was the most frequent risk identified, followed by self-destructiveness, substance abuse, and medication non-compliance. The final safety decision was associated most strongly with assaultiveness, self-destructiveness, and medication non-compliance. We conclude that it is possible to assess risk with measures that are available from shelter and medical records, and call for more research on the role of medication non-compliance in safety decisions and for longitudinal research to validate risk assessments.

Housing preferences and perceptions of health and functioning among homeless mentally ill persons.

OBJECTIVE: Most homeless persons who have received services for serious mental illness want to live on their own, but mental health professionals usually recommend group housing. This study examined the relationship between the types of residential arrangements preferred by homeless mentally ill persons and their demographic and clinical characteristics and perceptions of their health and functional status. METHODS: The study sample consisted of 118 homeless mentally ill persons living in publicly funded shelters in Boston who were enrolled in a research demonstration project that would provide them with housing. Before random assignment to housing, study participants were interviewed about their interest in moving, in staff support, and in living with others. Their clinical status and functional strengths and impairments were assessed using a variety of objective and subjective measures. RESULTS: Study participants reported a marked preference for independent living but expressed substantial interest in staff support. The desire for independent living was associated with a perceived ability to manage independent living, but was also associated with current substance abuse. Most indicators of clinical status and functional ability were not associated with housing preferences. CONCLUSIONS: Self-perceived functional ability may not be an influence on housing preferences, except when that ability is perceived as making independent living more difficult. Symptoms of mental illness did not appear to interfere with study participants' rational decision making about where to live. However, the study finding that substance abusers expressed a desire for independent living suggests the need for caution in adhering to homeless mentally ill persons' housing preferences, given the problems posed by substance abuse for their ability to maintain stable community housing.

Comparison of clinicians' housing recommendations and preferences of homeless mentally ill persons.

Housing recommendations made by two clinicians for 86 homeless mentally ill consumers were compared with the consumers' own housing preferences. Clinicians recommended independent living much less often than did the consumers. The two groups varied less on specific housing features such as eagerness for consumers to leave the shelter and consumers' need for part-time staff help. Only one of the clinicians took into account some aspects of social background and health status in formulating housing recommendations. The authors conclude that housing providers should encourage clinicians to work together with consumers to identify appropriate placements.

Use of mental health services by formerly homeless adults residing in group and independent housing.

OBJECTIVE: The study examined patterns of mental health service use among 112 formerly homeless mentally ill adults to determine whether clients in a staffed group living situation would need fewer types of services or lesser amounts of some services than those living independently in single apartments. METHODS: Clients in the Boston McKinney demonstration project were randomly assigned to two housing types: individual apartments or a group living situation designed to teach residents to manage the house and their own affairs with minimal staff presence. The types and amounts of services these clients used during an 18-month period were documented and compared. RESULTS: Service use by all clients was heavy, especially use of inpatient psychiatric services. It did not differ by housing type. The large majority of clients in both housing types were able to remain housed and avoid homelessness. Clients who did not stay in assigned housing for the duration of the study had higher levels of inpatient service use, including detoxification and substance abuse treatment. CONCLUSIONS: When homeless mentally ill adults are provided permanent housing and accessible mental health treatment and specialized social services, they are likely to avoid unstable housing patterns, which are associated with higher use of inpatient services.

Distress, suicidal thoughts, and social support among homeless adults.

Influences on psychological distress and suicidal thoughts are evaluated with a sample of 218 sheltered homeless adults. Levels of distress and suicidal thoughts are much higher than in the general population, and are comparable to those found by Rossi (1989). Perceived social support lessens distress and suicidal thoughts directly and also buffers homeless persons from the distress associated with traumatic experiences. There is little indication of a mediating (intervening) role of social support. Distress and suicidal thoughts are also associated with increased health problems; homeless history and sociodemographic characteristics are less important as predictors. Distress itself increases suicidal thoughts--directly, and also in interaction with low levels of social support. We conclude that distress among homeless persons is explained by the same types of influences as those that account for distress among the general population--the gravity of homeless persons' economic situation does not preclude sensitivity to the benefits of social support.

Characterization of monoclonal antibodies to two Treponema denticola serotypes by the indirect fluorescent-antibody assay.

Members of the genus Treponema have been implicated as possible aetiologic agents of periodontal disease. Previously developed murine monoclonal antibodies (MAbs) to two Treponema denticola strains were characterized by an indirect fluorescent-antibody (IFA) technique. Fifteen T. denticola strains and 32 other bacteria commonly isolated from periodontal pockets were used in the screening process. Two monoclonal antibodies to T. denticola ATCC 33521, serotype B, reacted with five T. denticola isolates, and one monoclonal antibody to T. denticola ATCC 33520, serotype c, reacted with two T. denticola isolates. There was no cross-reactivity between MAbs to the two serotypes. Preliminary tests of the MAbs on human periodontal samples show that they are useful in detecting these bacteria in clinical samples.

Glass bead sterilisation of surgical dental burs.

Since burs used in OMF surgery are a source of microbial contamination, sterilisation of the burs is an important aspect of infection control. A two-part study was performed to evaluate the efficacy of using the glass bead steriliser to sterilise long-shank burs. The laboratory and clinical studies indicated that the glass bead steriliser was effective in sterilising long-shank burs in 60 s.

Bactericidal effect of a disinfectant dental stone on irreversible hydrocolloid impressions and stone casts.

Infection control in dentistry focuses on the prevention of cross-contamination among patients, dentists, and dental auxilary personnel. This study evaluated the bactericidal effect of a dental gypsum material containing 0.25% chloramine-T on oral irreversible hydrocolloid impressions and dental casts. Eighty irreversible hydrocolloid impressions from 40 human volunteers were prepared. Forty impressions were poured with the disinfectant dental stone and a similar number were poured with a comparable, nondisinfectant stone. After setting for 60 minutes, the impressions and separated casts were sampled for bacterial contamination. The disinfectant stone inhibited bacterial growth in 39 of 40 impressions and casts, whereas all casts and impressions poured with the nondisinfectant stone were contaminated. The disinfectant dental stone containing chloramine-T was effective in eliminating bacterial contamination of both the irreversible hydrocolloid impression and stone cast.

Types of strength training.

Strength gains may be obtained by performing any type of resistance training if voluntary maximal contractions are performed. It is necessary that the advantages and disadvantages of a particular type of strength training are carefully considered before incorporating it into a program. Variables that should be considered include cost of equipment, motor performance increases, amount of strength gains, and range of motion of the strength gains. Further research comparing the different types of strength training is needed.

The management of orthopedic patients with arterial insufficiency.

The identification and management of the orthopedic patient who has chronic arterial insufficiency is presented in four cases in which failure to appreciate marginal arterial supply led to major and costly complications. Every orthopedic surgeon treating elderly patients should be aware of these possibilities. After a through history and physical examination, patients with signs or symptoms of significant arterial compromise should be evaluated by means of Doppler segmental limb pressures. This evaluation should be performed prior to the institution of the indicated orthopedic treatment whenever possible. If the segmental ankle pressure is less than 50 mm Hg, or the ankle brachial pressure index is less than 0.3, the patient should undergo complete vascular evaluation and consideration for revascularization in order to preserve marginal arterial flow and tissue perfusion during and after the orthopedic procedure. Constrictive straps, bandages, or dressings should be scrupulously avoided, as well as decreasing tissue perfusion by unnecessarily elevating the already vascular compromised extremity. The development of pain or ulceration after lower extremity surgery mandates immediate consideration of arterial ischemia and the institution of appropriate diagnostic and therapeutic measures to improve circulation to the extremity.