DEVELOPMENT OF CLINICAL DEMENTIA RATING SCALE CUTOFF SCORES FOR PATIENTS WITH PARKINSON'S DISEASE

BACKGROUND

The purpose of this study was to explore validity of the Clinical Dementia Rating Scale in measuring cognitive impairment among individuals with Parkinson's disease. The scale was created for use in patients with Alzheimer's disease and, to date, there have been no published studies examining if this tool is appropriate for patients with Parkinson's disease.

METHODS

The data were obtained from the National Alzheimer's Coordinating Center database and included 490 subjects diagnosed with Parkinson's disease, further categorized as having Parkinson's disease dementia (n= 151), mild cognitive impairment (n= 186), or normal cognition (n = 153) by a treating physician. Sensitivity, specificity, positive predictive value and negative predictive values were calculated for the Clinical Dementia Rating Scale Global Score as well as the Sum of Boxes Score using existing cutoff scores. Finally, new cutoff scores were calculated using sensitivity and specificity values derived using Receiver Operating Characteristic curves.

RESULTS

Sensitivity and specificity of the published Global Score cutoff scores for patients with dementia were .34 and .10, respectively. The newly calculated cutoff scores for patients with dementia yielded a sensitivity of .79 and a specificity of .96. The area under the curve was 0.92 (95% CI = 0.90-0.95).

CONCLUSION

The CDR is a useful tool in identifying dementia in patients with Parkinson's disease when the cutoff scores are adjusted.

Recurrent syncope due to refractory cerebral venous sinus thrombosis and transient elevations of intracranial pressure

Chronic paroxysmal intracranial hypertension leading to syncope is a phenomenon not reported previously in patients with refractory cerebral venous sinus thrombosis. We report a case of paroxysmal intracranial hypertension leading to syncopal episodes in a patient with idiopathic autoimmune hemolytic anemia and venous sinus thrombosis. This case demonstrates that intermittent elevations in intracranial pressure can lead to syncope in patients with venous sinus thrombosis and emphasizes the importance of considering this potentially treatable etiology of syncopal episodes.

Effects of cognitive remediation on neurocognitive functions and psychiatric symptoms in schizophrenia inpatients

OBJECTIVE

Many individuals diagnosed with schizophrenia have significant neurocognitive deficits, especially in the areas of attention, memory, and executive function. These deficits may exacerbate patients' psychiatric symptoms. Cognitive remediation has shown efficacy in improving neurocognitive functioning and may lead to amelioration of psychiatric symptoms in persons with schizophrenia.

METHOD

Forty-two schizophrenic inpatients were randomly assigned to either a cognitive remediation group (n=21) or a control group (n=21) and were assessed using a neuropsychological battery and symptom scales for depression, anxiety, and positive and negative symptoms of schizophrenia at baseline and after two months of participation in a cognitive remediation program.

RESULTS

The intervention group showed significant improvements in neuropsychological functioning, depression and negative symptoms of schizophrenia after the intervention compared to the control group.

CONCLUSION

Results of the study provide support for cognitive remediation as an efficacious intervention to improve neurocognitive functioning and decrease psychiatric symptoms of schizophrenia.

Development of an oral operant nicotine/ethanol co-use model in alcohol-preferring (p) rats

BACKGROUND

Alcohol abuse is frequently associated with nicotine (Nic) use. The current experiments were conducted to establish an oral operant ethanol + Nic (EtOH + Nic) co-use model and to characterize some aspects of EtOH + Nic co-use.

METHODS

Rats were allowed to choose between EtOH alone or EtOH + Nic solutions. Additionally, alcohol-preferring (P) rats were allowed to concurrently self-administer 3 distinct EtOH solutions (10, 20, and 30%) with varying amounts of Nic (0.07, 0.14, or 0.21 mg/ml) under operant conditions. P rats were also allowed to concurrently self-administer 2 distinct amounts of Nic (0.07 and 0.14 mg/ml) added to saccharin (Sacc; 0.025%) solutions.

RESULTS

During acquisition, P rats responded for the EtOH + Nic solutions at the same level as for EtOH alone, and responding for EtOH + Nic solutions was present throughout all drinking conditions. P rats also readily maintained stable self-administration behaviors for Nic + Sacc solutions. The results demonstrated that P rats readily acquired and maintained stable self-administration behaviors for EtOH + 0.07 and EtOH + 0.14 mg/ml Nic solutions. Self-administration of EtOH + 0.21 mg/ml Nic was established in only 50% of the subjects. P rats readily expressed seeking behaviors for the EtOH + Nic solutions and reacquired EtOH + Nic self-administration during relapse testing. In addition, tail blood samples indicated that EtOH + Nic co-use resulted in pharmacologically relevant levels of both EtOH and Nic in the blood.

CONCLUSIONS

Overall, the results indicate that P rats readily consume EtOH + Nic solutions concurrently in the presence of EtOH alone, express drug-seeking behaviors, and will concurrently consume physiologically relevant levels of both drugs. These results support the idea that this oral operant EtOH + Nic co-use model would be suitable for studying the development of co-abuse and the consequences of long-term chronic co-abuse.

Sexual selection maintains whole-body chiral dimorphism in snails

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called ‘antisymmetry’) in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome.

Population structure and coil dimorphism in a tropical land snail

Tree snails of the subgenus Amphidromus s. str. are unusual because of the chiral dimorphism that exists in many species, with clockwise (dextrally) and counter-clockwise (sinistrally) coiled individuals co-occurring in the same population. Given that mating in snails is normally impeded when the two partners have opposite coil, positive frequency-dependent selection should prevent such dimorphism from persisting. We test the hypothesis that a strong population structure with little movement between tree-based demes may result in the fixation of coiling morphs at a very small spatial scale, but apparent dimorphism at all larger scales. To do so, we describe the spatial structure in a Malaysian population of A. inversus (Müller, 1774) with 36% dextrals. We marked almost 700 juvenile and adult snails in a piece of forest consisting of 92 separate trees, and recorded dispersal and the proportions of dextrals and sinistrals in all trees over a 7-day period. We observed frequent movement between trees (155 events), and found that no trees had snail populations with proportions of dextrals and sinistrals that were significantly different from random. Upon recapture 1 year later, almost two-thirds of the snails had moved away from their original tree. We conclude that population structure alone cannot stabilise the coil dimorphism in Amphidromus.

The emotional effects of tooth loss in partially dentate people attending prosthodontic clinics in dental schools in England, Scotland and Hong Kong: a preliminary investigation

AIM

To compare the emotional effects of tooth loss in three partially dentate populations.

DESIGN

A questionnaire survey.

MATERIALS AND METHODS

A questionnaire was completed by 150 partially dentate subjects undergoing routine prosthodontic care at Guy's, King's and St Thomas's Dental Institute, London; the Dental School, Dundee, Scotland; and the Faculty of Dentistry, University of Hong Kong. Data were analysed using the Chi-square test.

RESULTS

Forty nine per cent of all participants reported difficulties in accepting the loss of some of their teeth. People from Dundee were less likely to have difficulties accepting tooth loss (P = 0.001). People from London took longer to come to terms with their tooth loss and were more likely to feel less confident (P < 0.001). Fifty five per cent of all participants restricted their choice of foods and 54 per cent had not enjoyed their food as much as before. Fewer people in Dundee restricted their choice of food (P < 0.001) and were more likely to enjoy their food (P = 0.009). People in Hong Kong were most likely to restrict their choice of food (P = 0.006). Thirty five percent of all subjects felt unprepared for the effects that tooth loss had upon them. People in Hong Kong were more prepared for tooth loss than those in Dundee and London (P = 0.003). In addition, they were less concerned about leaving their dentures out overnight (P = 0.024).

CONCLUSIONS

The emotional effects of tooth loss were significant in all groups. People from London took longer to come to terms with their tooth loss.

Evaluation of the impact and acceptance of a nutrition program in an HIV community clinic

The present paper describes the evaluation of a nutrition service and research model for human immunodeficiency virus (HIV)-positive clients within a community based HIV acquired immune deficiency syndrome (AIDS) medical clinic. This program was designed to develop an effective, practical, replicable model for the delivery of nutrition services in the ambulatory HIV care setting. The objectives of evaluating the model were to define the ways that nutrition services in HIV/AIDS impacted clients, the clinic, and referral sources, and to continually refine the model by determining what services provide greatest benefit to clients, especially in view of the changing landscape of HIV therapy. Four evaluation activities completed during the study period of 5 years are described. These included a focus group and semistructured interview with clients, a semistructured interview with workers from the local network of service referral agencies and a client satisfaction survey at study "close-out." These evaluation processes confirmed or prompted programmatic modifications that improved access, confidentiality, and the relevance of specific components for clients. Providers/stakeholder's concerns were addressed through more frequent communication about clients' specific nutrition issues, clearer and easier referral and cooperation in recruiting patients. Also, the evaluation activities provided a platform for the communication of general and specific information about the program and for outreach. Although clients' and workers' priorities differed in some details of program implementation, there was strong agreement on the value of addressing nutrition concerns in HIV. Favorable feedback about the program gave impetus to continue nutrition services in the clinic after the project period ended and supports its application in other sites and settings.

Mesostructured materials for optical applications: from low-k dielectrics to sensors and lasers

Recent advances on the use of mesoporous and mesostructured materials for electronic and optical applications are reported. The focus is on materials which are processed by block-copolymer templating of silica under weakly acidic conditions and by employing dip- and spin-coating as well as soft lithographic methods to bring them into a well-defined macroscopic shape. Several chemical strategies allow the mesostructure architecture to be used for electronic/optical applications: Removal of the block-copolymers results in highly porous, mechanically and thermally robust materials which are promising candidates for low dielectric constant materials. Since the pores are easily accessible, these structures are also ideal hosts for optical sensors, when suitable are incorporated during synthesis. For example, a fast response optical pH sensor was implemented on this principle. As-synthesized mesostructured silica/block-copolymer composites, on the other hand, are excellently suited as host systems for laser dyes and photochromic molecules. Laser dyes like rhodamine 6G can be incorporated during synthesis in high concentrations with reduced dimerization. This leads to very-low-threshold laser materials which also show a good photostability of the occluded dye. In the case of photochromic molecules, the inorganic-organic nanoseparation enables a fast switching between the colorless and colored form of a spirooxazine molecule, attributed to a partitioning of the dye between the block-copolymer chains. The spectroscopic properties of these dye-doped nanocomposite materials suggest a silica/block-copolymer/dye co-assembly process, whereby the block-copolymers help to highly disperse the organic dye molecules.

A transcultural perspective on the emotional effect of tooth loss in complete denture wearers

PURPOSE

The purpose of this study was to compare the emotional effects of tooth loss in three edentulous populations.

MATERIALS AND METHODS

A questionnaire study involved 142 edentulous subjects undergoing routine prosthodontic care at Guy's, King's and St Thomas's Dental Institute, London; the Dental School, Dundee, Scotland; and the Faculty of Dentistry, University of Hong Kong. Data were analyzed using the chi-squared test.

RESULTS

Difficulty in accepting tooth loss was a relatively common experience (44%) in all groups, with almost half feeling that their confidence had been affected. The majority (66%) felt that their choice of food was restricted and that the overall eating experience was less enjoyable, particularly the Hong Kong group. A significant proportion of the participants were concerned about their appearance without dentures, although the trend was less marked in Hong Kong. Forty-three percent felt that they were not adequately prepared for tooth loss, although the Hong Kong group was least concerned.

CONCLUSION

In general, the emotional effect of tooth loss was significant in all groups. The restrictions on daily activities were generally greater in the Hong Kong group. However, this group was much less inhibited by denture wearing. The differences observed in the Hong Kong Chinese are most likely due to different cultural values and expectations associated with these aspects of daily living.

An investigation into the use of a structured clinical operative test for the assessment of a clinical skill

AIM

This study was designed to investigate the level of agreement between a group of assessors observing students undertaking a structured clinical operative test.

METHOD

3 assessors agreed a series of criteria to assess the performance of undergraduate students in the recording of a dental impression. Guidelines for assessing whether the students adequately performed in relation to each criteria were also agreed. Following preliminary validation between the assessors, 2 assessors independently scored the performance of each student by reference to the agreed criteria, and the levels of agreement between assessors were compared. The 3 assessors worked in pairs with each other on three groups of students who were in the early stages of their clinical course.

RESULTS

A total of 39 clinical dental students were assessed in the recording of a dental impression. The 3 pairs of assessors had satisfactory levels of agreement in the study with similar judgements being made on 90% or more of the 12 criteria assessed. Some differences existed between the pairs of assessors. Certain criteria were more easily judged than others and this was reflected in the level of agreement seen. For over 90% of the criteria, positive assessments were made by each of the 3 assessors, and although there were minor variations between the pairs of assessors, this may have reflected the ability of the groups of students studied.

CONCLUSION

The study showed that different assessors were generally able to make agreed judgements on performance criteria in a structured clinical operative test. In setting up performance assessment it is necessary to have close collaboration between assessors to make clearly defined criteria so that judgements are not too subjective. Furthermore, for the assessment of more complex clinical skills, great care is needed in assembling criteria that can be used reproducibly, and sufficient preparation time for the assessors is critical.

Laser scanning of the ear identifying the shape and position in subjects with normal facial symmetry

The objective of the present study was to discover if dimensional measurements of the ear could be determined with a laser scanning technique and whether or not the location of landmarks of the ear could be reliably measured with respect to those on the midline of the face. Computer-generated images were created from laser scans of 20 subjects. Dimensional measurements were made between landmarks on the ear and face. Differences between repeated dimensional measurements of the ear were very small, as were those measurements made between landmarks on the ear to the midline of the face. Differences between dimensions of the left and right ears were observed, but were of a small magnitude. The results suggest that the dimensions of the ear and its position with respect to landmarks in the midline of the face can be reliably measured on normal subjects and that laser scanning is a useful technique for planning and monitoring facial reconstruction of the ear.

Nutrition and cancer education: ten years of progress

The Nutrition Education and Research Program at the University of Nevada School of Medicine was awarded two separate NIH/NCI R25 cancer education grants over a ten-year period. With this support, a four-year longitudinal nutrition curriculum was implemented, including the required 20-hour freshman Medical Nutrition Course, junior and senior nutrition electives, and a senior assignment in nutrition and cancer during the rural rotation with faculty preceptors. Funding has also supported nutrition integration into the basic science courses, patient care courses, and specialty clerkships. A unique nutrition fellowship for medical students who specialize in nutrition during their four years of training and graduate with special Qualifications in Nutrition (SQIN) has also been instituted. The curriculum reflects a longitudinal, interdisciplinary, but flexible, integration of nutrition into an already crowded medical school education.

The contribution of mechanoreceptive neurones in the gingival tissues to the masticatory-parotid salivary reflex in man

The masticatory-parotid salivary reflex has been studied in fully dentate subjects. Salivary flow was recorded by siting a modified Lashley cup over the orifice of the parotid duct on one side of the mouth. Subjects chewed on small pieces of silicone rubber for 1-min periods which resulted in a reflex secretion of parotid saliva. The secretion was greatest when the subject chewed on the same side of the mouth (ipsilateral) as the salivary flow was recorded. Less salivary flow resulted when the subjects chewed on the opposite side of the mouth (contralateral). Selected areas of the buccal or lingual gingival tissues were then anaesthetized on the side ipsilateral to the Lashley cup. Anaesthesia of the lingual and buccal gingival tissues together resulted in a reduction of salivary flow in response to similar chewing cycles. Anaesthesia of the lingual gingival tissues alone also resulted in a reduction of salivary flow, but anaesthesia of the buccal gingival tissues alone did not. During mastication it is likely that mechanoreceptors in the gingival tissues will be stimulated which may result in salivary flow. This requires further study as other mechanoreceptive neurones are also known to be involved in the masticatory-parotid salivary reflex.

An assessment of the influence of clinical demonstrations on the confidence of undergraduate dental students, when treating patients requiring removable partial dentures

AIM

This study was designed to assess the influence of clinical demonstrations, on the confidence of undergraduate dental students, when treating patients requiring removable partial dentures.

METHOD

The confidence of 45 undergraduate dental students treating their first patient requiring removable partial dentures was assessed using questionnaires. 23 students were given demonstrations prior to carrying out the treatment; the remainder did not receive a demonstration. Outcome was assessed by the time taken to complete the procedures to a clinically acceptable standard.

RESULTS

All the students indicated high levels of agreement with a statement expressing their confidence in coping with the clinical procedures undertaken. The more confident students completed their clinical procedures more quickly than other students, irrespective as to whether they had received a demonstration or not. There was a higher proportion of more confident students in the groups who had received a clinical demonstration; it can therefore be concluded that these groups performed better, as measured by the time taken to achieve the required clinical standard. All the students who had received a demonstration believed they had benefited from it, whilst 67% of the students who had not received a demonstration believed they would have benefited from one. Analysis of the students' comments indicated that demonstrations facilitated confidence, communication skills, understanding and recall in the clinical situation. Students who did not perceive a benefit from the demonstrations believed that they had more time for one to one teaching.

CONCLUSION

This study showed that those students who had received a clinical demonstration immediately prior to treating their patients believed they were more confident and as a result their performance was improved. Clinical demonstrations are time consuming, but they would appear to be time well spent.

Case report: Complications of rehabilitation using osseointegrated implants--tardive dyskinesia

The oral rehabilitation of patients using osseointegrated dental implants is a well established treatment modality. However complications can arise during the provision of treatment. This case report describes the management of a patient exhibiting tardive dyskinesia with an implant stabilised mandibular overdenture. Complications of the treatment and their resolution are discussed.

Case report: complications of rehabilitation using osseointegrated implants--tardive dyskinesia

The oral rehabilitation of patients using osseointegrated dental implants is a well established treatment modality. However complications can arise during the provision of treatment. This case report describes the management of a patient exhibiting tardive dyskinesia with an implant stabilised mandibular overdenture. Complications of the treatment and their resolution are discussed.

The masticatory-parotid salivary reflex in edentulous subjects

The parotid-masticatory salivary reflex has been studied in edentulous subjects. Salivary flow was recorded by siting a modified Lashley cup over the orifice of the parotid duct on one side of the mouth. Subjects chewed on small pieces of silicone rubber with their complete dentures for 1 min periods which resulted in a reflex secretion of parotid saliva. The secretion was greatest when the subject chewed on the same side of the mouth (ipsilateral) as the salivary flow was recorded. Less salivary flow resulted when the subjects chewed on the opposite side of the mouth (contralateral). Anaesthesia of the mucosa of the maxillary and mandibular denture-bearing area was achieved by placing a thin layer of anaesthetic ointment in the fitting surface of the dentures on the side ipsilateral to the Lashley cup. This resulted in a reduction of salivary flow in response to similar chewing cycles. The results confirmed the presence of a parotid-masticatory salivary reflex in edentulous subjects which appears similar in many respects to that of dentate subjects. It is likely that receptors in the oral mucosa are stimulated when an edentulous subject masticates with complete dentures and that activity in these mechanoreceptive neurones results in the reflex salivary secretion.

Evidence-based dentistry: endodontic failure--how should it be managed?

OBJECTIVE

To review the evidence on the most appropriate management of failed endodontic treatment.

DATA SOURCES

Appropriate articles were selected from the international literature.

RESULTS

There was good evidence that conventional endodontic treatment is associated with a successful outcome in a significant proportion of cases. The results of surgical treatment are more difficult to interpret since account should be made of the status of the existing root filling. However, there is evidence of an increased success rate with a satisfactory orthograde root filling.

CONCLUSIONS

It is difficult to make direct comparisons from cited studies to advance a clear argument in support of one treatment modality. However, it is judged that a conventional endodontic retreatment approach is the most appropriate in the first instance, providing access to the root canal is possible. This does not preclude a subsequent surgical approach. Teeth that are permanently restored soon after retreatment are more successful than those which are not. There are significant challenges in setting up prospective research studies to directly address the problem of the failed root filing.

Laser scanning for the identification of repeatable landmarks of the ears and face

OBJECTIVE

To determine whether or not landmarks of the ears and face could be reliably identified using a laser scaning system.

DESIGN

A single centre study with two assessors jointly agreeing the siting of the landmarks on the ear on two separate occasions from an original laser scanned image.

SETTING

University based research study in London, UK.

SUBJECTS

20 subjects, 11 males, 9 females, aged 16-24 years with normal facial development.

MAIN OUTCOME MEASURES

Differences were determined between the locations of landmarks on the two occasions studied. Differences were assessed for the x, y and z co-ordinates of each point.

RESULTS

The mean difference between the two sitings of 21 landmarks ranged between 0 and 0.85 mm in the x, y and z axes. With a small number of exceptions, the differences were not statistically significant. The three-dimensional mean differences between the two sitings of each landmark ranged between 1 and 2.5 mm. Coefficients of repeatability ranged between 1.6 and 7.0 mm.

CONCLUSIONS

Landmarks of the ears and face from a laser scanned image can be sited consistently by two assessors. Since the landmarks can be located it should be possible to evaluate dimensional measurements of the ear and its position on the face.

A classification system to evaluate weight maintainers, gainers, and losers

OBJECTIVES

To study natural weight changes and to develop a weight classification system that can identify weight maintainers, gainers, and losers. DESIGN/OUTCOME: A prospective, observational study in which weight changes over five annual measurements were evaluated. In the weight classification system used, changes greater than 5 lb defined weight maintenance, gain, or loss.

SUBJECTS/SETTINGS

Subjects were healthy, normal-weight and over weight, men and women (mean age = 44.1 +/- 14.1 years) in the Relationships of Energy, Nutrition, and Obesity to Cardiovascular Disease Risk Study. Prospective data for 385 of the original 508 subjects for whom actual weights were available for each of the 5 years (1985 to 1990) were used to classify and characterize subjects by weight-change categories.

STATISTICAL ANALYSES

Cross-tabulations (with chi 2 tests) and hterarchical log-linear analyses (with partial chi 2 tests) to examine the relationships of categorical variables; analyses of variance (with F tests) for continuous measures.

RESULTS

Over the 4-year interval, 46% of subjects were classified as maintainers, 34% as gainers, and 20% as losers. Over shorter 1-year epochs, more subjects were maintainers (62%) and fewer subjects were gainers (22%) or losers (16%). Maintainers had fewer and smaller magnitudes of weight fluctuations and showed fewer deleterious changes in health risk factors than gainers.

APPLICATIONS

Weight changes of greater than +/-5 lb can classify a person as a weight maintainer, or loser. Although annual weight changes were used in this study, a weight change of more than 5 lb between any two points in time may suggest nonmaintenance of weight or weight instability that needs further evaluation.

The challenge of replacing complete dentures: Part 2

The purpose of this article is to consider the challenges that arise in replacing complete dentures. The use of conventional techniques incorporating successful features of the existing dentures appropriate to general practice will be discussed and the problems peculiar to the replacement of implant-retained overdentures considered.

The challenge of replacing complete dentures: Part 1

Complete dentures need to be replaced at suitable intervals-either because of changes in the denture-bearing tissues, usually due to alveolar resorption, or because of general deterioration of the existing dentures. The purpose of this and the following article is to consider the challenges that arise in replacing complete dentures. The rationale for using techniques in which features of existing dentures can be employed in the construction of replacement complete dentures will be discussed, together with methods suitable for clinical practice. In the first part diagnosis and treatment planning will be considered and a variety of copying techniques reviewed. The limitations of these techniques will be discussed and alternative treatment strategies will be considered.

Who are the weight maintainers?

To characterize people who maintain weight over long periods of time, normal weight and obese adults (n = 385) were studied over five annual visits. Subjects were classified using a +/- 5 lb change between the first and the fifth year visits to determine overall maintenance (M), with gain (G) or loss (L) being any change outside this range. This MGL status was cross-tabulated with a Fluctuation Index which counted the number of successive year-to-year weight changes of more than +/- 5 lbs (F0 through F4). True maintainers were defined as those having all weight changes within +/- 5 lbs during the 5-year period (M and F0). Nineteen percent (n = 73) of the subjects were classified as True Maintainers and included three times as many normal weight as obese subjects. Obese subjects comprised only 25% of the True Maintainer group but 60% of the Non-Maintainer group. Age had no association with Maintainer status. Standard measures of weight variability were lowest among True Maintainers and highest in Non-Maintainers. In addition, True Maintainers had lower BMI, Percent Body Fat, and Waist-Hip Ratios than Non-Maintainers. Subjects classified as Non-Maintainers were more likely to engage in dieting, by a variety of measures, than True Maintainers--this was particularly true among obese subjects. Finally, changes in total cholesterol, LDL and HDL cholesterol, and systolic and diastolic blood pressure were not reliably associated with Maintainer status, although the ordering of the group means suggested that True Maintainers had slightly healthier levels of "risk" variables. Overall, the results suggest that True Maintainers comprise a potentially important and interesting group of individuals who need further study.

Role of periodontal mechanoreceptors in evoking reflexes in the jaw-closing muscles of the cat

1. In anaesthetized cats the left maxillary and mandibular canine and incisor teeth were extracted. Nine weeks later the animals were anaesthetized again and titanium implants were placed into the edentulous ridge of the maxilla and mandible. 2. Terminal experiments were performed between 9 weeks and 10 months after inserting the implants. Recordings were made from the trigeminal ganglia and peripheral nerves of anaesthetized cats. Neurones were identified which responded to forces applied to the maxillary teeth but none was found which responded to forces applied to the implant. 3. The responses of motor units in the temporalis muscle were studied in response to ramp-plateau forces applied to the maxillary canine tooth and maxillary implant using peristimulus time histograms and cumulative sum (cusum) analysis. A small amount of inhibition of the motor units was observed in response to the applied forces to the implant. However, the inhibition was much more profound when similar forces were applied to the tooth. 4. The results confirm that when forces are applied to a tooth, periodontal mechanoreceptors are stimulated which evoke reflex inhibitions to motor units in the jaw-closing muscles. However, there is evidence that mechanoreceptors situated distant to the periodontium can also evoke such reflexes. 5. The results are discussed in relation to the overall functional role of periodontal mechanoreceptors in the reflexes of mastication.

Criterion based audit in prosthetic dentistry

A criterion based retrospective audit into the provision of complete dentures in an undergraduate teaching programme has been produced. This consisted of a series of questions related to the treatment of the patient and the satisfaction or otherwise expressed about the treatment. The audit revealed where treatment had been successful according to the established criteria. It has been found that an audit of this nature is demanding of clinicians' time but does show where improvements can be made in patient management which will result in better health care. Clinical audit is now recognized as forming an important part of health care. It is applicable to all areas of dentistry, ie general dental practice, the community dental services and the hospital services, and to all specialities eg prosthetics, orthodontics etc. An audit programme needs careful planning and a pilot study is worthwhile to indicate areas of difficulty. This audit has been used in an undergraduate training programme, however, the process by which the audit has been assembled is an example of how an audit could be established in any area of dentistry, provided that the criteria are modified to make them relevant to the clinical speciality.

Prosthetic assessment in the treatment of denture hyperplasia

The removal of denture-induced trauma is important in the treatment of denture hyperplasia and in the prevention of its redevelopment in susceptible patients. A simple approach to the assessment of dentures is described, which highlights potentially damaging areas of the borders and the fitting surface.

Particle size determines the efficiency of calcitic limestone in amending acidic soil

There is a commonly held view that limestone particles <0.25 mm are fully effective in amending acidic soils. However, this is not consistent with some available data. We assessed the importance of particle size in a field experiment using six particle size segregations covering a range of mean diameters from 3 mm to 0.005 mm. These products were applied at rates of 2.5, 5 and 10 t ha-1. Lime was incorporated in April 1986 and soil samples were collected 6, 12, 24 and 36 months later. The experiment was cropped to wheat in 1986, 1987 and 1989. Effectiveness was evaluated as the capacity of the particle size segregation to increase soil pH, exchangeable calcium (Caex,) or grain yield of wheat. No minimum particle size for maximum effectiveness was identified. Throughout the range of particle sizes evaluated, progressively finer particles produced larger increases in pH and Caex. Wheat yield was related to soil pH. Changes in soil pH and Caex between 6 months and 3 years after lime application were small compared to the changes in the first 6 months. Fine lime products should be preferred in practice, subject to cost considerations and handling difficulties.

Subterranean clover pasture responses to lime application on the acid soils of southern New South Wales

The effects of soil amendment with shallow (0-10 cm) incorporated lime or dolomite were examined at 3 sites with acid soils over 6 years. Measurement was made of soil pH and exchangeable cations, and of subterranean clover dry matter production, seed set, and concentrations of calcium, magnesium, manganese, nitrogen and phosphorus. Application of lime or dolomite increased the production of dry matter, but not by the alleviation of molybdenum deficiency. Response in yield ranged from nil to 47%, with most responses in the range 20-35%. Such responses persisted for 5-6 seasons following lime or dolomite application. Differences in soil pH associated with liming were maintained for the 6 years of measurement, so that the benefits in pasture production from soil amendment are likely to accrue beyond the time span of this study. The analyses of plant dry matter indicated that manganese toxicity may have been a factor in the response to lime at 1 harvest, and that higher nitrogen concentration was associated with liming at another. Generally, the plant analyses did not indicate a clear mechanism for the plant responses to lime, although the soil analyses indicated the presence of exchangeable aluminium in the unamended plots at all 3 sites. The plant responses demonstrated that acidity constrained the yield of subterranean clover grown on these soils.

A new predictive equation for resting energy expenditure in healthy individuals

A predictive equation for resting energy expenditure (REE) was derived from data from 498 healthy subjects, including females (n = 247) and males (n = 251), aged 19-78 y (45 +/- 14 y, mean +/- SD). Normal-weight (n = 264) and obese (n = 234) individuals were studied and REE was measured by indirect calorimetry. Multiple-regression analyses were employed to drive relationships between REE and weight, height, and age for both men and women (R2 = 0.71): REE = 9.99 x weight + 6.25 x height - 4.92 x age + 166 x sex (males, 1; females, 0) - 161. Simplification of this formula and separation by sex did not affect its predictive value: REE (males) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) - 161. The inclusion of relative body weight and body-weight distribution did not significantly improve the predictive value of these equations. The Harris-Benedict Equations derived in 1919 overestimated measured REE by 5% (p less than 0.01). Fat-free mass (FFM) was the best single predictor of REE (R2 = 0.64): REE = 19.7 x FFM + 413. Weight also was closely correlated with REE (R2 = 0.56): REE = 15.1 x weight + 371.

Distribution of magnesium in subterranean clover (Trifolium subterraneum L.) in relation to supply

The objectives of this study were to examine Mg distribution in subterranean clover (Trifolium subterraneum L.), to identify an appropriate tissue for diagnosis of deficiency and to establish minimum tissue concentrations associated with maximum plant growth. Plants were grown in solution culture with both discontinued (40 8M and 160 8M reduced to nil) and constant supply (0, 5, 10, 20, 40, 80, 160 8M Mg). Magnesium was depleted from old leaves when Mg supply to the roots was interrupted. However, deficiency symptoms occurred first on the young tissue under these conditions. Under constant but inadequate supply, initial deficiency symptoms occurred in old tissue. Symptoms in leaves were associated with Mg concentrations in the leaf of < 1046 8g g-1 with constant root supply and 586 8g g-1 when supply was interrupted. At luxury constant supply, concentrations of Mg tended to be higher in the older leaves than in the young leaves; the reverse occurred with inadequate supply. Tissue choice for diagnosis was not critical, but the minimum Mg concentration in tissue commensurate with maximum shoot growth varied from 740 8g g-1 for the unifoliate leaf to 1310 8g g-1 in the youngest open leaf (YOL), when plants were grown under constant Mg supply. Current supply of Mg to roots was reflected more rapidly in the concentrations in young leaf than in old leaf tissue.

Changes in the content and form of magnesium in the first trifoliate leaf of subterranean clover under altered or constant root supply

Little is known of the forms of magnesium (Mg) in leaf tissue and how these forms may differ with increasing and decreasing Mg concentration in the leaf. In the present study, plants of subterranean clover (Trifolium subterraneum L.) were grown in solution, with increasing, decreasing and stable root supply of Mg over the range 0-160 8m. Old leaf tissue was sampled in six harvests over 21 days. The chlorophyll was extracted from the leafwith dimethyl sulfoxide. This partitioned Mg into that in either the chlorophyll or residual fibre after extraction, and that Mg unaccounted for by these fractions ('other'). The forms of Mg in leaves could be related to the Mg concentration in the leaf and were not influenced by whether the concentration in the leaf was increasing or decreasing. Chlorophyll concentration was stable at about 1% when the concentration of Mg in the leaf was greater than 776 8g g-1. Below this Mg concentration, the concentration of chlorophyll declined rapidly. The proportion of total leaf Mg in the chlorophyll ranged from 6% at 5000 8g g-1 Mg in leaf to 35% at 700 8g g-1. Magnesium associated with the residual fibre was generally 80% of the total tissue Mg, although this appeared to be about 60% when Mg concentrations in leaves were < 1000 8g g-1. When the Mg concentration in the first trifoliate leaf was below 600 to 800 8g g-1, the leaf showed symptoms of Mg deficiency and became relatively heavier than non-deficient leaves.

Distribution of mesencephalic nucleus and trigeminal ganglion mechanoreceptors in the periodontal ligament of the cat

1. In anaesthetized cats recordings have been made in the mesencephalic nucleus of the fifth cranial nerve and the trigeminal ganglion from neurones that respond when forces are applied to the mandibular canine tooth. The site of the mechanoreceptors in the periodontal ligament and their distribution around the tooth root have been determined. 2. Receptors with their cell bodies in the mesencephalic nucleus were found to be situated in the periodontal ligament in a discrete area intermediate between the fulcrum and apex of the tooth, while those in the trigeminal ganglion were situated in the whole area of the periodontal ligament between the fulcrum and apex of the tooth. 3. All of the located mechanoreceptors responded maximally when that part of the ligament in which they lay was put under tension. 4. The directional sensitivities of the mechanoreceptors suggested that there was an uneven distribution around the tooth root of receptors with cell bodies in the mesencephalic nucleus. In contrast mechanoreceptors with cell bodies in the trigeminal ganglion were distributed more equally around the tooth root. The rationale for the differences requires further investigation.

The effect of tooth extraction on periodontal ligament mechanoreceptors represented in the mesencephalic nucleus of the cat

When a force is applied to a tooth, mechanoreceptors in the periodontal ligament are stimulated. When teeth are extracted the remnants of the periodontal ligament break down and disappear, but it is not known what happens to the mechanoreceptor neurones that innervated it. The present study seeks to determine the effect of tooth extraction on the population of periodontal ligament mechanoreceptor neurones represented in the mesencephalic nucleus of the fifth cranial nerve. The incisor and canine teeth were extracted from adult cats; terminal experiments were performed between 7.5 months and 2 yr later. Recordings were made in the mesencephalic nucleus with microelectrodes, and neurones were identified in the inferior alveolar nerve that previously innervated the periodontal ligament of one of the extracted mandibular teeth. The majority of these neurones responded only to electrical stimuli applied to the edentulous ridge of the mandible in the area where the incisor or canine teeth had previously been. It was not possible to stimulate them mechanically, despite the use of large forces. A small number had reinnervated new soft-tissue sites. They could be mechanically stimulated and were found adjacent to the area in which the mandibular incisor and canine teeth had been. Thus the population of periodontal ligament mechanoreceptor neurones represented in the mesencephalic nucleus do not all degenerate after tooth extraction. As the majority of those still present do not appear to reinnervate new tissues in which they can be mechanically stimulated, it is unlikely that they have any functional role after tooth loss.

The influence of surface incorporated lime on subsurface soil acidity

The aim of this study was to establish whether surface incorporated liming materials could reduce subsurface acidity. Three sites on the southwest slopes of New South Wales, between Wagga and Albury, were sampled at 2 cm depth increments to 16 cm, 5 years after the liming materials were applied. Limestone and dolomite had been applied at 0,2 and 8 tlha in 3 replicates. At 2 t/ha the effect of the liming materials on pH was largely confined to the depth of incorporation. At 8 t/ha substantial pH increases occurred to 6 cm or more below the depth of incorporation. In general, the movement of Mg>Ca> HCo3 (pH), and was consistent with the soil's ability to hold those cations and to neutralize alkalinity respectively. Agriculturally realistic liming rates are not likely to ameliorate subsurface soil acidity on the south-west slopes of New South Wales.

Isolation of nuclei from melittin-destabilized cells

Melittin, the hydrophobic polypeptide from bee venom, sufficiently destabilizes the plasma membrane of cultured cells to allow cell disruption in the absence of detergents with minimal homogenization. Nuclei are thus isolated in high yield with intact nuclear membranes and high transcriptional activity.

Failure of liming to increase grain yield of wheat and triticale in acid soils may be due to the associated increase in incidence of take-all (Gaeumannomyces graminis var. tritici)

Lime was applied at rates from 0 to 5.0 t ha-1 at 4 sites in southern and central New South Wales. A root and crown disease characterised by basal stem blackening affected up to 60% of wheat plants and 80% of triticale plants when the soil pH in 0.01 mol L-1 CaCl2 was above 5.0 at all 4 sites. Below pH 4.8, incidence was less than 5%. The take-all fungus, Gaeumannomyces graminis var. tritici, was consistently associated with this symptom. Losses in grain yield from the disease ranged from 26 to 77% depending on site. Regression analysis indicates that each 10% increase in plants with basal stem blackening decreased yield by 0.76%. These results demonstrate that the disease can reverse the expected increase in yield after liming, and that progressive acidification of the soils in the region may have caused the present reduced amount of take-all.

Determination of organic acids in seven wheat varieties by capillary gas chromatography

Fresh wheat tops were extracted with acidic 90% ethanol, and the ethanol was evaporated and a portion of the aqueous residue loaded onto DEAE-Sephadex. Organic acids were eluted with pyridinium formate and then lyophilized and the dried residue was derivatized with 1% trimethylchlorosilane in bis(trimethylsilyl)trifluoroacetamide. The acids were then quantitatively determined using capillary gas chromatography and identified using capillary gas chromatography-mass spectrometry. The acidic ethanol extraction of fresh plant tissue was quantitative for all acids except citric while losses in the remaining procedures were controlled by using an internal standard. The ion exchange chromatography made the greatest contribution to experimental error, imposing a minimum loading requirement of 0.1 mumol of each acid for adequate precision. Organic acid profiles were determined for seven wheat cultivars (Triticum aestivum cv Carazinho, Teal, Lance, Warigal, Isis, Maringa, and BH1146) grown on gravel in solution culture for 30 days. Profiles were simple, consisting of only malic, aconitic, and citric acids, with levels of each acid for all varieties falling within the range 2-5 mumol/g fresh tissue. Storage of samples led to a large increase in sampling error and increased the amount of extractable citric acid.

Identification of the serum binding proteins for iron, zinc, cadmium, nickel, and calcium

The binding of five biologically important metals to serum proteins has been studied. After suitable radioactive isotopes were added to serum proteins separated and precipitated by two-dimensional immunoelectrophoresis, the sample plates were exposed to roentgenogram film. 59Fe bound to transferrin alone; 65Zn bound mostly to albumin, but also to another 12 proteins; 109Cd was mostly associated with alpha 2-macroglobulin, but was also present on albumin, immunoglobulins G and A, and prealbumin; 63Ni, added in high concentration, was associated with an alpha 2-mobility protein and albumin; and, finally, 45Ca was mostly bound to albumin, but seven other binding proteins were also identified, with transferrin predominant. The results are not quantitative, but the technique is simple and specific, and the information gained can direct further studies on isolated proteins.

Identification of the serum binding proteins for iron, zinc, cadmium, nickel, and calcium

The binding of five biologically important metals to serum proteins has been studied. After suitable radioactive isotopes were added to serum proteins separated and precipitated by two-dimensional immunoelectrophoresis, the sample plates were exposed to roentgenogram film. 59Fe bound to transferrin alone; 65Zn bound mostly to albumin, but also to another 12 proteins; 109Cd was mostly associated with alpha 2-macroglobulin, but was also present on albumin, immunoglobulins G and A, and prealbumin; 63Ni, added in high concentration, was associated with an alpha 2-mobility protein and albumin; and, finally, 45Ca was mostly bound to albumin, but seven other binding proteins were also identified, with transferrin predominant. The results are not quantitative, but the technique is simple and specific, and the information gained can direct further studies on isolated proteins.

The identification of serum ligand-binding proteins using immuno-precipitation techniques and autoradiography

The identification of ligand-binding proteins in serum is important for understanding many metabolic pathways and for interpreting clinical measurements. Most techniques presently available lack the facility to identify specific binding proteins. This problem has been overcome by combining the specificity of immunological methods with the sensitivity of radioisotope detection. The methods comprise an adaptation of 2-dimensional immuno-electrophoresis, and radial immunodiffusion, combined with radiolabelled ligands and autoradiography. They have been used to determine the serum binding of calcium, cadmium, thyroxine and the beta blocking drug propranolol. This technique has wide application to other ligand-binding interactions.

Current Land Use in the Poplar Box (Eucalyptus Populnea) Lands

Poplar box (Eucalyptus populnee) woodlands mainly occuron duplex, clay and red earth soils between the 300 mm and 750 mm rainfall isohyets. The poplar box lands have been occupied for from 100 to 150 years and have been modified extensively through tree felling, ringbarking, clearing, cultivation, burning and grazing by domestic livestock. The current land use is described for six vegetation groups which together comprise the poplar box lands. The eastern areas of the poplar box lands are mainly used for intensive agriculture based on wheat. barley and grain sorghum, with small areas sown to c~ops of high water demand. Mixed farming involves dairying (in Queensland) and fat lambs (in New South Wales) and broad-acre cereal and fodder cropping. Sheep and cattle grazing replace intensive crop production as the rainfall decreases. In all areas used for cropping the stability and fertility of the soil are of paramount importance in maintainihg production. The use of woodlands in areas of lower rainfall can lead to deterioration of the resource and to the encroachment of woody native species into the grazing lands. Because cropping is unreliable the opportunity to use cultivation to control woody regrowth is reduced. In central areas much of the land can be sown to improved pastures, but in western areas diversification is limited by the low rainfall and land use is restricted to grazing, initially only by sheep but now by sheep and cattle. Particularly in western New South Wales the increase in unpalatable shrubs and the decrease in available forage has resulted in low stocking rates, and high grazing pressure, making reclamation and pasture improvement difficult. In consequence many enterprises are becoming uneconomic.