Trajectories of frailty among Chinese older people in Hong Kong between 2001 and 2012: an age-period-cohort analysis.

Background: there is little evidence to suggest that older people today are living in better health than their predecessors did at the same age. Only a few studies have evaluated whether there are birth cohort effects on frailty, an indicator of health in older people, encompassing physical, functional and mental health dimensions. Objectives: this study examined longitudinal trajectories of frailty among Chinese older people in Hong Kong. Methods: this study utilised data from the 18 Elderly Health Centres of the Department of Health comprising a total of 417,949 observations from 94,550 community-dwelling Chinese people aged ≥65 years in one early birth cohort (1901-23) and four later birth cohorts (1924-29, 1930-35, 1936-41, 1942-47) collected between 2001 and 2012, to examine trajectories of the frailty index and how birth cohorts may have contributed to the trends using an age-period-cohort analysis. Results: more recent cohorts had higher levels of frailty than did earlier cohorts at the same age, controlling for period, gender, marital status, educational levels, socioeconomic status, lifestyle and social factors. Older age, being female, widowhood, lower education and smoking were associated with higher levels of frailty. Conclusion: more recent cohorts had higher levels of frailty than did earlier cohorts. Frailty interventions, coupled with early detection, should be developed to combat the increasing rates of frailty in Hong Kong Chinese.

A versatile RNA vector for delivery of coding and noncoding RNAs.

The discovery that RNA viruses, lacking any DNA intermediate, can be engineered to express both coding and noncoding RNAs suggests that this platform may have therapeutic value as a delivery vehicle. Here we illustrate that a self-replicating, noninfectious RNA, modeled on influenza virus, provides one such example of a versatile in vivo delivery system for silencing and/or expressing a desired RNA for therapeutic purposes.

Hong Kong College of Physicians Position Statement and Recommendations on the 2017 American College of Cardiology/American Heart Association and 2018 European Society of Cardiology/European Society of Hypertension Guidelines for the Management of Arterial Hypertension.

The American College of Cardiology/American Heart Association released guidelines for the prevention, detection, evaluation, and management of high blood pressure (BP) in adults in 2017. In 2018, the European Society of Cardiology (ESC)/European Society of Hypertension (ESH) published new guidelines for the management of arterial hypertension. Despite the many similarities between these two guidelines, there are also major differences in the guidelines in terms of diagnosis and treatment of hypertension. A working group of the Hong Kong College of Physicians (HKCP) convened and conducted a focused discussion on important issues of public interest, including classification of BP, BP measurement, thresholds for initiation of antihypertensive medications, BP treatment targets, and treatment strategies. The HKCP concurs with the 2018 ESC/ESH guideline on BP classification, which defines hypertension as office systolic BP ≥140 mm Hg and/or diastolic BP ≥90 mm Hg. The HKCP also acknowledges the growing evidence of home BP monitoring and ambulatory BP monitoring in the diagnosis and monitoring of hypertension and endorses the wider use of both methods. The HKCP also supports the direction of a risk-based approach for initiation of antihypertensive medications and the specification of a treatment target range for both systolic and diastolic BP with consideration of different age-groups and specific disease subgroups. Non-pharmacological interventions are crucial, both at the societal and individual patient levels. The recent guideline publications provide good opportunities to increase public awareness of hypertension and encourage lifestyle modifications among the local population.

Computed tomography angiography intraluminal filling defect is predictive of internal carotid artery free-floating thrombus.

INTRODUCTION: Filling defects at the internal carotid artery (ICA) origin in the work-up of stroke or transient ischemic attack may be an ulcerated plaque or free-floating thrombus (FFT). This may be challenging to distinguish, as they can appear morphologically similar. This is an important distinction as FFT can potentially embolize distally, and its management differs. We describe a series of patients with suspected FFT and evaluate its imaging appearance, clinical features, and evolution with therapy. METHODS: Between 2008 and 2013, we prospectively collected consecutive patients with proximal ICA filling defects in the axial plane surrounded by contrast on CT/MR angiography. We defined FFT as a filling defect that resolved on follow-up imaging. We assessed the cranial-caudal dimension of the filling defect and receiver operating characteristics to identify clinical and radiological variables that distinguished FFT from complex ulcerated plaque. RESULTS: Intraluminal filling defects were identified in 32 patients. Filling defects and resolved or decreased in 25 patients (78 %) and felt to be FFT; there was no change in 7 (22 %). Resolved defects and those that decreased in size extended more cranially than those that remained unchanged: 7.3 mm (4.2-15.9) versus 3.1 mm (2.7-3.7; p = 0.0038). Receiver operating characteristic analysis established a threshold of 3.8 mm (filling defect length), sensitivity of 88 %, specificity of 86 %, and area under the curve of 0.86 (p < 0.0001) for distinguishing FFT from plaque. CONCLUSION: Filling defects in the proximal ICA extending cranially >3.8 mm were more likely to be FFT than complex ulcerated plaque. Further studies evaluating filling defect length as a predictor for FFT are warranted.

Revisiting the Kittel's model of antiferroelectricity: phase diagrams, hysteresis loops and electrocaloric effect.

We revisit the Kittel's model of antiferroelectricity by extending the model to study the phase transitions, hysteresis loop behaviors and electrocaloric effect (ECE) of antiferroelectrics (AFEs). By considering both the first- and second-order AFEs, explicit expressions for the physical and staggered polarizations of AFEs in the stable states are derived. We also obtain the analytical solutions for describing the dielectric susceptibilities of AFEs in the AFE and paraelectric (PE) phases. Coercive fields in AFE are also derived and studied. To verify the usefulness of the Kittel's model of antiferroelectricity, we apply the model to systematically investigate the phase transitions, hysteresis loops and ECEs of PbZrO3(PZO). By adopting appropriate values of the Kittel's parameters for first-order transition, analytical and numerical results are obtained and discussed. Our results show that PZO exhibits a complex temperature (T)-electric field (E) phase diagram, consisting of the AFE, ferroelectrics, ferrielectric, PE and mixed phases. TheT-Ephase diagram is qualitatively agreed with the new AFE model that was derived based on symmetry by Tolédano and Khalyavin (2019Phys. Rev.B99024105). We found that the calculated zero-field dielectric susceptibility is qualitatively and quantitatively agreed with experimental results. We show that the polarizations and dielectric susceptibilities of PZO in heating and cooling deviate from each other, as expected for the first-order materials. Our calculated results also reveal that the ECE in PZO has an electro-heating of ΔT≈ +6.5 °C and an electro-cooling of ΔT≈ -4.0 °C, respectively, which are comparable to the experimental results.

Use of nutritional health supplements and associated factors among parents with children at kindergartens in Hong Kong.

OBJECTIVES. To estimate the prevalence of so-called nutritional health supplement consumption among kindergarten children; secondarily to explore potential factors associated with such consumption. DESIGN. Cross-sectional, self-administered questionnaire survey. SETTING. One kindergarten each in Hong Kong island, Kowloon, and the New Territories region. SUBJECTS. Parents who had a child studying at the three sampled kindergartens in April 2010. RESULTS. Of 951 sets of parents, 730 (77%) responded. Approximately 52% (95% confidence interval, 47-58%) of the respondents gave regular health supplements to their child. The commonest type of supplement given was cod fish oil (69%). Approximately 36% of the respondents did not know the upper limit dosage of their supplement. Parents of only 66% of regular health supplements consumers, compared to 75% of non-regular users, knew that there was an inherent risk from over-consumption (P=0.018). Parental beliefs that "It is useful/important for normal child development" (adjusted odds ratio=1.93; 95% confidence interval, 1.18-3.16; P=0.009), "It is useful/important for immune function" (1.79; 1.05-3.05; P=0.032) were associated with consumption of health such supplements. CONCLUSION. There is high rate of health supplement consumption among healthy kindergarten children in Hong Kong. There are wrong beliefs from parents that health supplements are important for normal-growing children for their normal growth and body immunity. About one-third of parents has limited knowledge on potential side-effects of overdose and do not know the limit of consumption. Education on "Less (health supplement) is more (health)" is recommended.

Rich antiferroelectric phase diagram of antiferroelectric-ferroelectric superlattices: internal electric field- and interface induced phase transitions.

We propose a thermodynamic model to the study the antiferroelectric (AFE) phase transitions in antiferroelectric-ferroelectric (AFE-FE) superlattices in which the coupling at the interface between two layers is mediated by local polarizations. Phase diagram of the AFE layer in term of the degree of interfacial effect λ and temperature T involving ferrielectric (FI) and ferroelectric (FE) phases is investigated. These two phases are stabilized by the interfacial effect and internal electric field. AFE thickness L AFE versus T phase diagram is also constructed. Intermediate regions of two-phase coexistence (IM) emerge in the λ-T and L AFE-T phase diagrams, if certain interface properties λ and layer thickness L AFE criteria are met. These IM regions are metastable states, which exist as a transition state between two phases. A tricritical point locates at the boundaries across the FI, IM and FE phases is found in the L AFE-T phase diagram. Competition among the internal electric field due to the electrostatic coupling, the FE ordering arises from the interfacial effect and the antiferroelectric ordering within the AFE layer giving rises to the rich AFE phase diagram.

A pilot study to examine the feasibility and acceptability of a community model for exercise prescription for patients with chronic disease.

1. A model of community care for chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) that incorporates exercise prescription is lacking, although the benefits of exercise for these diseases are established. 2. Group programmes incorporating exercise, disease education, and social support consisting of weekly sessions for 12 weeks were designed for COPD and CHF patients, in groups of 8 to 10. A home exercise programme was also prescribed. 3. This model was feasible, enjoyed good compliance, improved symptoms and measures of psychosocial outcome for both disease and improved exercise tolerance in the CHF group. 4. This model could be further developed as an integral part of community management for patients with chronic diseases.

A comparison of health expectancies over 10 years: implications for elderly service needs in Hong Kong.

OBJECTIVES: We aimed to estimate health expectancies at age 65 based on physical and cognitive function in 2001-2002 and 2011-2012 and project future needs for carers from 2021 to 2041. METHODS: Data from the Elderly Health Centres (EHCs) of the Department of Health of the Government of Hong Kong comprising of people aged 65 years or older who enrolled between 2001 and 2002 (EHC 2001-2002) and between 2011 and 2012 (EHC 2011-2012) provided proportion estimates for physical impairment (assessed by independence in activities of daily living) and cognitive impairment (assessed by Abbreviated Mental Test/Mini-Mental Status Examination and self-reported doctor diagnosis of dementia). Health expectancies (years lived with/without physical and/or cognitive impairment) were calculated by Sullivan's method. The proportions of physical and/or cognitive impairment were used to project future needs for carers. RESULTS: Between 2001-2002 and 2011-2012, years lived without physical/cognitive impairment decreased for men but increased for women, both of which were less than the increases in total life expectancy. Men assessed in 2011-2012 (classified as EHC 2011-2012) lived more years with physical and/or cognitive impairment than those assessed in 2001-2002 (classified as EHC 2001-2002), and women in EHC 2011-2012 lived more years with physical impairment, but fewer years with cognitive impairment than those in EHC 2001-2002, and women enrolled in EHC 2011-2012 lived more years with physical impairment, but fewer years with cognitive impairment than those in EHC 2001-2002. As populations age, the number of carers needed is expected to increase from 344,000 in 2021 to 629,000 by 2041, or an increase of 82.9%. Sensitivity analyses excluding the participants who had been assessed in 2011-2012 from EHC 2001-2002 gave similar estimations. CONCLUSIONS: Increased life expectancy was not accompanied by an increase in years lived without physical/cognitive impairment. These findings suggest that people will live longer but could be more dependent, which would have considerable implications for elderly service needs in Hong Kong.

Examining item bias in the anxiety subscale of the Hospital Anxiety and Depression Scale in patients with chronic obstructive pulmonary disease.

The Hospital Anxiety and Depression Scale (HADS) is a widely used screening instrument for depression and anxiety in medically compromised patients. The purpose of this study was to examine the differential item functioning (DIF) of the anxiety subscale of the HADA (HADS-A). A research assistant administered the HADS-A to 166 Chinese patients with chronic obstructive pulmonary disease (COPD) who were consecutively admitted to a rehabilitation hospital. Although the HADS-A was overall uni-dimensional, there were one mute item and two items with borderline misfit. Only one item had a DIF for arterial oxygen saturation. No item had DIF for other indicators of the severity of COPD. In conclusion, this study found that for one item the HADS-A has significant item bias for the severity of disease in patients with COPD.

Canadian Stroke Best Practice Recommendations for Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care, 6th Edition, Update 2018.

The 2018 update of the Canadian Stroke Best Practice Recommendations for Acute Stroke Management, 6th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by healthcare providers and system planners caring for persons with very recent symptoms of acute stroke or transient ischemic attack. The recommendations are intended for use by a interdisciplinary team of clinicians across a wide range of settings and highlight key elements involved in prehospital and Emergency Department care, acute treatments for ischemic stroke, and acute inpatient care. The most notable changes included in this 6th edition are the renaming of the module and its integration of the formerly separate modules on prehospital and emergency care and acute inpatient stroke care. The new module, Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care is now a single, comprehensive module addressing the most important aspects of acute stroke care delivery. Other notable changes include the removal of two sections related to the emergency management of intracerebral hemorrhage and subarachnoid hemorrhage. These topics are covered in a new, dedicated module, to be released later this year. The most significant recommendation updates are for neuroimaging; the extension of the time window for endovascular thrombectomy treatment out to 24 h; considerations for treating a highly selected group of people with stroke of unknown time of onset; and recommendations for dual antiplatelet therapy for a limited duration after acute minor ischemic stroke and transient ischemic attack. This module also emphasizes the need for increased public and healthcare provider's recognition of the signs of stroke and immediate actions to take; the important expanding role of paramedics and all emergency medical services personnel; arriving at a stroke-enabled Emergency Department without delay; and launching local healthcare institution code stroke protocols. Revisions have also been made to the recommendations for the triage and assessment of risk of recurrent stroke after transient ischemic attack/minor stroke and suggested urgency levels for investigations and initiation of management strategies. The goal of this updated guideline is to optimize stroke care across Canada, by reducing practice variations and reducing the gap between current knowledge and clinical practice.

Drug non-adherence and associated risk factors among Chinese geriatric patients in Hong Kong.

OBJECTIVES: To study the prevalence of drug non-adherence among Chinese elderly people and its associated risk factors. DESIGN: Cross-sectional survey. SETTING: Medical and Geriatrics specialist out-patient clinic in a regional hospital. PATIENTS: Elderly patients (> or =65 years) with chronic diseases requiring regular medications were selected by systematic sampling. MAIN OUTCOME MEASURES: Drug non-adherence; potential risk factors studied include patients' factors, availability of assistance, and prescription factors. RESULTS: Two hundred and nine elders participated with 84% response rate. Estimated mean prevalence rate of drug non-adherence was 37% (standard deviation, 7%). The risk factors for drug non-adherence were: (1) self-perceived adverse drug effects (odds ratio=2.5; 95% confidence interval, 1.2-5.2; P=0.017); (2) use of respiratory drugs (2.7; 1.0-7.5; P=0.048); (3) complicated drug regimens (7.4; 3.2-16.9; P<0.001); and (4) necessity to cut tablets (4.8; 2.1-10.7; P<0.001). Presence of caregiver/community nursing services assistance to pack medication (odds ratio=0.2; 95% confidence interval, 0.1-0.5; P=0.001), and the use of medication boxes (0.5; 0.3-1.0; P=0.050) were found to be the protective factors against drug non-adherence. CONCLUSION: Drug non-adherence is an important concern in patient management. Medication regimen should be simplified as far as possible, in particular to avoid cutting pills or use of different dosage at different timing. Patients receiving drugs for respiratory diseases should be the first target group for intervention. Patients should be encouraged to voice out their perceived adverse drug effects.

Microcatheter navigation and thrombolysis in acute symptomatic cervical internal carotid occlusion.

BACKGROUND AND PURPOSE: The treatment of acute stroke distal to an occluded cervical internal carotid artery (ICA) presents a challenge. We report our results of endovascular therapy in 7 patients presenting with acute symptomatic cervical ICA occlusion. PATIENTS AND TECHNIQUES: Among patients presenting with acute stroke at our institution from June 2001 to June 2005, we retrospectively identified 7 patients who underwent endovascular therapy of acute cervical ICA occlusion. The techniques used for vessel recanalization were analyzed. Postprocedure CT scans were reviewed for hemorrhage. The clinical outcomes were assessed by using the modified Rankin scale (mRS) with good outcomes assigned scores of < or =2. RESULTS: All 7 patients revealed cervical ICA occlusion, with additional intracranial thrombus in 6 of the 7 patients. In all patients, a guiding catheter was placed in the ipsilateral common carotid artery proximal to the occlusion and a microcatheter advanced through the ICA clot to deliver intra-arterial (IA) tissue plasminogen activator (in 6 patients, the microcatheter was also advanced intracranially for thrombolysis). Successful recanalization of the occluded ICA was achieved in 6 patients. In 3 patients, balloon angioplasty and stent placement of the cervical ICA was also performed. Follow-up CT in 6 patients showed small basal ganglia infarcts in 4, patchy parietal infarcts in one, and frontal lobe hematoma in one patient. At 1 month after the procedure, 5 patients had good clinical outcomes (mRS of 0 in 4 patients and 1 in one patient). CONCLUSION: Performance of IA thrombolysis by passing a microcatheter through an acutely occluded internal carotid artery may be an effective therapy in acute stroke.

AML multi-gene panel testing: A review and comparison of two gene panels.

BACKGROUND/OBJECTIVE: Risk adapted therapy is standard practice in Acute Myeloid Leukemia (AML). A common diagnostic approach involves focusing on a three gene panel (CEPBA, FLT3, and NPM1). However, a complete representation of prognostic and predictive factors in AML necessitates an expanded series of genes, due to the dynamic interactions present between concurrent mutations. Hence, the current study aims to describe the benefits of an expanded risk profile in an unselected cohort of AML cases. METHODS: The genomes of 11 randomly selected patients with AML were sequenced using next generation sequencing. A narrow three gene panel and broader 50 gene panel were contrasted. RESULTS: The expanded gene panel detected one additional pathogenic mutation in five patients and two pathogenic mutations in two patients, resulting in a change in their risk profile. Only 5/11 (45%) of AML patients demonstrated a pathogenic mutation on the 3 gene profile, however all patients had at least one detectable pathogenic mutation on the broader gene panel. The detection of a concurrent mutation by the expanded gene panel reversed the favorable risk profile for three patients. CONCLUSIONS: Detection of concurrent mutations enables rejection or validation of prognoses associated with NPM1 or CEBPA mutations. DNMT3a and TP53 mutations in AML have a pertinent prognostic and therapeutic value for patients and their addition enhances the current three gene panel. In our small study, the three gene panel changed the prognosis for three patients (3/11, 27%) with the detection of commonly occurring AML mutations.

Trends in activities of daily living disability in a large sample of community-dwelling Chinese older adults in Hong Kong: an age-period-cohort analysis.

BACKGROUND: To examine the trends in activities of daily living (ADL) disability in older Chinese adults in Hong Kong between 2001 and 2012. METHODS: Using data from the Elderly Health Centres (EHCs) of the Department of Health comprising a total of 54 808 community-dwelling Chinese adults aged ≥65 years in 1 early cohort (1904-1917) and 10 3-year birth cohorts (1918-1920, 1921-1923, 1924-1926, 1927-1929, 1930-1932, 1933-1935, 1936-1938, 1939-1941, 1942-1944, 1945-1947), we examined trends in ADL disability by using age-period-cohort (APC) models. ADL disability was defined as being unable to perform at least 1 of 7 ADL activities (bathing, dressing, toileting, transferring, feeding, grooming, walking) independently. Cross-classified random-effects logistic regressions were performed for each of the APC trends with adjustment for age, period, cohort, sociodemographic, lifestyle, comorbidity and self-rated health. RESULTS: The mean age of the cohort was 70.9±4.7 (range 65-99) years. The prevalence rate of ADL disability was 1.6%. ADL disability increased with age (p<0.001) and the gradient of the increase was steeper in the older age groups. At the same age, women (1.7%) were more likely to report ADL disability than men (1.4%, p=0.001). For both genders, there was an increase in ADL disability between 2003 and 2012; adjustment for age, cohort and other covariates has diminished the trends observed among men. There was no cohort effect in ADL disability. CONCLUSIONS: ADL disability in older adults has increased over the last decade. Further study is required to identify possible causes behind the disability trends.

Aneurysmal SubArachnoid Hemorrhage-Red Blood Cell Transfusion And Outcome (SAHaRA): a pilot randomised controlled trial protocol.

INTRODUCTION: Anaemia is common in aneurysmal subarachnoid haemorrhage (aSAH) and is a potential critical modifiable factor affecting secondary injury. Despite physiological evidence and management guidelines that support maintaining a higher haemoglobin level in patients with aSAH, current practice is one of a more restrictive approach to transfusion. The goal of this multicentre pilot trial is to determine the feasibility of successfully conducting a red blood cell (RBC) transfusion trial in adult patients with acute aSAH and anaemia (Hb ≤100 g/L), comparing a liberal transfusion strategy (Hb ≤100 g/L) with a restrictive strategy (Hb ≤80 g/L) on the combined rate of death and severe disability at 12 months. METHODS: Design This is a multicentre open-label randomised controlled pilot trial at 5 academic tertiary care centres. Population We are targeting adult aSAH patients within 14 days of their initial bleed and with anaemia (Hb ≤110 g/L). Randomisation Central computer-generated randomisation, stratified by centre, will be undertaken from the host centre. Randomisation into 1 of the 2 treatment arms will occur when the haemoglobin levels of eligible patients fall to ≤100 g/L. Intervention Patients will be randomly assigned to either a liberal (threshold: Hb ≤100 g/L) or a restrictive transfusion strategy (threshold: Hb ≤80 g/L). Outcome Primary: Centre randomisation rate over the study period. Secondary: (1) transfusion threshold adherence; (2) study RBC transfusion protocol adherence; and (3) outcome assessment including vital status at hospital discharge, modified Rankin Score at 6 and 12 months and Functional Independence Measure and EuroQOL Quality of Life Scale scores at 12 months. Outcome measures will be reported in aggregate. ETHICS AND DISSEMINATION: The study protocol has been approved by the host centre (OHSN-REB 20150433-01H). This study will determine the feasibility of conducting the large pragmatic RCT comparing 2 RBC transfusion strategies examining the effect of a liberal strategy on 12-month outcome following aSAH. TRIAL REGISTRATION NUMBER: NCT02483351; Pre-results.

Adenomatous polyposis coli gene promoter hypermethylation in non-small cell lung cancer is associated with survival.

Methylation of 5' CpG islands in promoter and upstream coding regions has been identified as a mechanism for transcriptional inactivation of tumor suppressor genes. The purpose of this study was to determine whether hypermethylation of the adenomatous polyposis coli (APC) gene promoter occurs in primary non-small cell lung cancer (NSCLC), and whether hypermethylated APC has any relationship with survival. APC promoter 1A methylation was determined in normal and corresponding tumor tissue from 91 NSCLC patients and in a control group of 10 patients without cancer, using a quantitative fluorogenic real-time PCR (Taqman) system. APC promoter methylation was detectable in 86 (95%) of 91 tumor samples, but also in 80 (88%) of 91 normal samples of NSCLC patients, and in only two (20%) of 10 normal lung tissues of the control group. The median level of APC promoter methylation was 4.75 in tumor compared to 1.57 in normal lung tissue (P<0.001). Patients with low methylation status showed significantly longer survival than did patients with high methylation status (P=0.041). In a multivariate analysis of prognostic factors, APC methylation was a significant independent prognostic factor (P=0.044), as were pT (P=0.050) and pN (P<0.001) classifications. This investigation shows that APC gene promoter methylation occurs in the majority of primary NSCLCs. High APC promoter methylation is significantly associated with inferior survival, showing promise as a biomarker of biologically aggressive disease in NSCLC.

Sugar binding to purified fractions from bovine taste buds and epithelial tissue. Relationships to bioactivity.

Binding of various sugars was compared in purified subfractions of taste buds isolated from bovine circumvallate papillae and of non-taste bud-bearing epithelium isolated from tissue surrounding these papillae. Binding of 14C-labeled sugars was greater in purified subfractions obtained from taste bud than from non-taste bud-bearing tissue and was, in general, greater in those taste bud subfractions in which a greater membrane purification was achieved. Binding specificity of the 14C-labeled sugars sucrose, fructose, glucose and of 14C-labeled cyclamate and saccharine was measured by competition of each 14C-labeled sugar or synthetic sweetener with its unlabeled homologous sugar in P4(B) taste bud subfractions; this binding, as shown for sucrose, was reversible and temperature dependent. Essentially no competition of the 14C-lageled sugars sucrose, fructose, glucose or 14C-labeled cyclamate and saccharine by their respective unlabeled homologues occurred in epithelial tissue P4(B) subfractions; this binding was not reversible. Binding specificity was further observed by the competition of 14C-labeled sucrose, fructose and glucose with each unlabeled sugar for binding sites on P4(B) taste bud subfractions; unlabeled sucrose was more effective in competing with each 14C-labeled surgar than was unlabeled fructose or glucose. The relatively non-sweet sugar lactose did not compete with 14C-labeled lactose in P4(B) subfractions from either taste bud or non-taste bud-bearing epithelial tissue. Binding of 14C-labeled sucrose in purified P4(B) bud subfractions was inhibited by increased concentrations of unlabeled sucrose, phospholipase C, neuraminidase, EDTA, NaCl and urea. Dissociation constants for sugar or synthetic sweetener binding were low (approx. 10(-3) M) but in a rank order (sucrose greater than fructose greater than glucose greater than saccharine) consistent with preference and electrophysiological responses in cow. The cow is behaviorally indifferent to saccharine and lactose consistent with the data obtained in the present study.

Preparation and isolation of a taste bud-derived fraction from bovine circumvallate papillae.

A crude extract from taste buds was prepared from circumvallate papillae of bovine tongues by a procedure consisting of freezing, coring, excision, treatment with hypotonic buffer, nitrogen pressurization and selective homogenization. Examination of taste buds by light and electron microscopy before and after this procedure indicated that some of the contents of the buds, mainly from the more apical portions, was extruded following the procedure; anatomical changes could not be observed in the epithelial tissue immediately surrounding the taste buds.