User-Friendly Chatbot to Mitigate the Psychological Stress of Older Adults During the COVID-19 Pandemic: Development and Usability Study

BACKGROUND

To safeguard the most vulnerable individuals during the COVID-19 pandemic, numerous governments enforced measures such as stay-at-home orders, social distancing, and self-isolation. These social restrictions had a particularly negative effect on older adults, as they are more vulnerable and experience increased loneliness, which has various adverse effects, including increasing the risk of mental health problems and mortality. Chatbots can potentially reduce loneliness and provide companionship during a pandemic. However, existing chatbots do not cater to the specific needs of older adult populations.

OBJECTIVE

We aimed to develop a user-friendly chatbot tailored to the specific needs of older adults with anxiety or depressive disorders during the COVID-19 pandemic and to examine their perspectives on mental health chatbot use. The primary research objective was to investigate whether chatbots can mitigate the psychological stress of older adults during COVID-19.

METHODS

Participants were older adults belonging to two age groups (≥65 years and <65 years) from a psychiatric outpatient department who had been diagnosed with depressive or anxiety disorders by certified psychiatrists according to the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5) criteria. The participants were required to use mobile phones, have internet access, and possess literacy skills. The chatbot's content includes monitoring and tracking health data and providing health information. Participants had access to the chatbot for at least 4 weeks. Self-report questionnaires for loneliness, depression, and anxiety were administered before and after chatbot use. The participants also rated their attitudes toward the chatbot.

RESULTS

A total of 35 participants (mean age 65.21, SD 7.51 years) were enrolled in the trial, comprising 74% (n=26) female and 26% (n=9) male participants. The participants demonstrated a high utilization rate during the intervention, with over 82% engaging with the chatbot daily. Loneliness significantly improved in the older group ≥65 years. This group also responded positively to the chatbot, as evidenced by changes in University of California Los Angeles Loneliness Scale scores, suggesting that this demographic can derive benefits from chatbot interaction. Conversely, the younger group, <65 years, exhibited no significant changes in loneliness after the intervention. Both the older and younger age groups provided good scores in relation to chatbot design with respect to usability (mean scores of 6.33 and 6.05, respectively) and satisfaction (mean scores of 5.33 and 5.15, respectively), rated on a 7-point Likert scale.

CONCLUSIONS

The chatbot interface was found to be user-friendly and demonstrated promising results among participants 65 years and older who were receiving care at psychiatric outpatient clinics and experiencing relatively stable symptoms of depression and anxiety. The chatbot not only provided caring companionship but also showed the potential to alleviate loneliness during the challenging circumstances of a pandemic.

A Case Rarity: Papillary Thyroid Carcinoma with Squamous Metaplasia Complicated with Chronic Discharging Ulcers

We report a unique case of differentiated thyroid carcinoma (DTC) with squamous metaplasia complicated with chronic discharging ulcer. A 76-year-old gentleman was referred to us after defaulted treatment 1 year post-total thyroidectomy. He presented to us with long-standing chronic, non-healing, ulcerative and discharging wound at the anterior neck at previous total thyroidectomy scar. The primary tumour was histologically diagnosed as papillary malignant cells with extensive squamous metaplasia. Squamous metaplasia is a rare finding in thyroid carcinoma that carried a poorer prognostic factor.

Resilient healthcare in patient safety

No abstract available.

Skill validation study on sentinel lymph node biopsy in breast cancer and the challenges of false-negative, in-transit and micrometastatic nodes

No abstract available.

Allelopathic dominance ofMiscanthus transmorrisonensis in an alpine grassland community in Taiwan

A study site located at 2600 m elevation in Tartarchia Anpu, Nantou county, Taiwan, exhibits a unique grassland community composed of two principal species,Miscanthus transmorrisonensis andYushinia niitakayamensis, and 35 other species. The relative frequencies of the two species are 12% and 11%, while their relative coverages are 25% and 19.5%, respectively. The values for the remaining 35 species are lower than4% each, while species diversity of the community is -3.04839, indicating great diversity. To elucidate the mechanism of dominance ofM. transmorrisonensis, allelopathic evaluation of the plant was conducted. Aqueous extracts of M.Transmorrisonensis plant parts with two ecotypes were bioassayed. The extracts showed significant phytotoxic effects on seed germination and radicle growth of four tested plants: rye grass, lettuce, and two varieties of Chinese cabbage. In addition, rhizosphere soils underMiscanthus also exhibited significant phytotoxicity, indicating that allelopathic interaction was involved. Some responsible phytotoxic phenolics, namely, p-coumaric, ferulic, vanillic, protocatechuic, o-hydroxyphenylacetic, andm-hydroxyphenylacetic acids, and 4-hydroxycoumarin and phloridzin were identified. Allelopathy thus can play an important role in regulating plant diversity in the field.

Defect mediated photocatalytic decomposition of 4-chlorophenol on epitaxial rutile thin films under visible and UV illumination

We show that pure rutile TiO(2) can be photo-responsive even under low energy visible light after annealing in vacuum where we envisage that the point defects, i.e. oxygen vacancies and titanium interstitials, serve an important role. In this study, single crystal rutile films were grown by the pulsed laser deposition technique and then vacuum annealed under different oxygen pressures to introduce defects into their lattices. 4-chlorophenol was selected as a model material and decomposed by the annealed TiO(2) films where the maximum photocatalytic reaction rate constants were determined as 0.0107 and 0.0072 min(-1) under UV and visible illumination. Epitaxial growth along the [200] direction was confirmed by φ-scan and 2θ-scan XRD and the epitaxial relationship between the rutile film and the c-sapphire substrate was explained as (100)[010](R) [parallel] (0001)[12[combining overline]10](S). The formation of atomically sharp interfaces and the epitaxial growth were ascertained by annular dark-field STEM imaging. Based on the XPS, UV-vis and PL spectroscopy results, it was found that the defect concentration increased after annealing under lower pressures, e.g. 5 × 10(-6) Torr. In contrast, more perfect crystals were obtained when the films were annealed under high oxygen pressures, namely 5 × 10(1) Torr. The morphology of the films was also investigated by employing an AFM technique. It was observed that increase of the annealing pressure results in the formation of larger grains. It was also found that the electrical resistivity of the rutile films strongly increased by about three orders of magnitude when the annealing pressure increased from 5 × 10(-4) to 5 × 10(1) Torr.

Regression of early diabetic macular oedema is associated with prevention of dark adaptation

HYPOTHESIS

Dark-adapted rods consume oxygen at high rates and light adaptation decreases this oxygen burden and can have therapeutic effects on diabetic macular oedema (DMO).

METHODS

Patients with mild non-proliferative diabetic retinopathy (DR) and early, untreated non-sight-threatening DMO slept for 6 months wearing masks that illuminated the eyelid of one closed eye by 505 nm light. Exclusion criteria were any concomitant eye disease, DR >ETDRS grade 35, and other systemic diseases.

PRIMARY OUTCOME

change of OCT retinal thickness in the local region where oedema was present.

RESULTS

A total of 34 out of 40 patients completed the study. Mean baseline OCT macular cube thickness was equivalent for study and fellow eyes. But study eyes had a greater mean thickness in the central subfield zone 1 (282±53 μm) vs (256±19 μm) the fellow eyes. Twenty-eight study eyes showed intraretinal cysts compared with nine in the fellow eyes. At 6 months, only 19 study eyes had cysts while cysts were seen in 20 fellow eyes. After 6 months, the worst affected ETDRS zone and the central subfield zone 1 reduced in thickness in study eyes only by 12 μm (95% CI 20 to -7, P=0.01). The secondary outcomes of change in visual acuity, achromatic contrast sensitivity, and microperimetric thresholds improved significantly in study eyes and deteriorated in fellow eyes.

CONCLUSIONS

Sleeping in dim light that can keep rods light adapted may reverse the changes of DMO.

Mercury recovery from cold cathode fluorescent lamps using thermal desorption technology

Cold cathode fluorescent lamps (CCFLs) are globally used components of high technology products. A large amount of mercury in waste CCFLs is being recovered by thermal desorption technology in Taiwan. However, the complexity of the samples affects the thermal desorption efficiency and increases costs. This study identifies the mercury release behaviour of amalgam, phosphor and mercury-containing components as well as waste CCFLs by bench scale thermal desorption test. The results show that the mercury was released from amalgam and mercury/fluorescent powder from a real treatment plant at temperatures between 550 degrees C to 850 degrees C, which is much higher than from cinnabar at 300 degrees C to 380 degrees C and that of pure mercury, high pressure mercury lamps, and fluorescent tubes containing mercury/fluorescent-powder at 50 degrees C to 250 degrees C. In addition, the experiment also showed the mercury release peak of the mercury/fluorescent powders from a real treatment plant occurs at much higher temperatures than that of commercial phosphor at 50 degrees C to 200 degrees C. Thus, complete separation of the cracked CCFLs is necessary to effectively recover phosphor and mercury at low financial and energy cost.

Evaluation of C-2-substituted 19-nor-1alpha,25-dihydroxyvitamin D3 analogs as therapeutic agents for prostate cancer

1alpha,25-Dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) is known to inhibit the proliferation and invasiveness of prostate cancer cells. However, 1alpha,25(OH)(2)D(3) can cause hypercalcemia and is not suitable as a therapeutic agent. 19-Nor-vitamin D derivatives are known to be less calcemic when administered systemically. In order to develop more potent anti-cancer agents with less calcemic side effect, we therefore utilized (3)H-thymidine incorporation as an index for cell proliferation and examined the antiproliferative activities of nine C-2-substituted 19-nor-1alpha,25(OH)(2)D(3) analogs in the immortalized PZ-HPV-7 normal prostate cell line. Among the nine analogs we observed that the substitution with 2alpha- or 2beta-hydroxypropyl group produced two analogs having antiproliferative potency that is approximately 500- to 1000-fold higher than 1alpha,25(OH)(2)D(3). The (3)H-thymidine incorporation data were supported by the cell counting data after cells were treated with 1alpha,25(OH)(2)D(3), 19-nor-2alpha-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) or 19-nor-2beta-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) for 7 days. 19-Nor-2alpha-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) and 19-nor-2beta-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) were also shown to be about 10-fold more active than 1alpha,25(OH)(2)D(3) in cell invasion studies using prostate cancer cells. In conclusion, a substitution at the C-2 position of 19-nor-1alpha,25(OH)(2)D(3) molecule with a hydroxypropyl group greatly increased the antiproliferative and anti-invasion potencies. Thus, these two analogs could be developed to be effective therapeutic agents for treating early and late stages of prostate cancer.

Unusual pox lesions found in Chinese jungle mynahs (Acridotheres cristatellus)

Pox lesions involving feathered and unfeathered skin, the oral cavity and the uropygial gland were found in Chinese jungle mynahs. Characteristic intracytoplasmic inclusions were detected in the proliferative cells of all lesions. Ultrastructurally, the virus particles consisted of a convoluted outer membrane enclosing lateral bodies and a biconcave central core, typical for poxvirus. The nucleotide sequences of the amplicon obtained with a set of primers for the 4b core protein of fowl poxvirus revealed that the mynah poxvirus was phylogenetically related to wood pigeon poxvirus. This is the first report of poxvirus infection affecting the uropygial gland.

TR4 orphan receptor represses the human steroid 21-hydroxylase gene expression through the monomeric AGGTCA motif

The human TR4 orphan receptor (TR4) is a member of the nuclear receptor superfamily. It functions as a transcriptional factor which regulates and controls many important physiological functions. It has been documented that TR4 may bind as a homodimer to a DNA response element containing two direct repeats of the AGGTCA consensus motif. Surprisingly, our data reveal that the expression of the human steroid 21-hydroxylase (21-OHase) gene could be repressed by TR4 via the monomeric AGGTCA motif (-228TR4RE) at its 5' flanking region (nucleotide numbers 1431-1444, 5'-GGAAAAAGGTCAGG-3'). Electrophoretic mobility shift assay showed specific binding with a dissociation constant of 0.4 nM between TR4 and the monomeric -288TR4RE motif. However, TR4 does not form heterodimers with either retinoid X receptor alpha or SHP (short heterodimer partner) orphan receptor. Additionally, both dual-luciferase and chloramphenicol acetyltransferase assays demonstrated that TR4 can function as a repressor via the -228TR4RE of the 21-OHase gene. In conclusion, our data suggest that TR4 may bind to a monomeric DNA response element and play an important role in the suppression of the 21-OHase gene expression.

Diffuse toxoplasmic retinochoroiditis as the initial manifestation of acquired immunodeficiency syndrome

Toxoplasmic retinochoroiditis is an important opportunistic retinal infection in human immunodeficiency virus (HIV)-infected patients. It may present as diffuse necrotizing retinochoroiditis instead of a focal lesion and may be the initial manifestation of HIV infection. A 50-year-old heterosexual man presented with blurred vision in his left eye of 3 months' duration. Fundus examination revealed diffuse necrotizing retinochoroiditis, mainly at the posterior pole, with marked vitritis in the left eye. Serologic studies and aqueous fluid antibody titers indicated recent toxoplasmic infection. Positive enzyme immunoassays (EIA) and Western blot tests proved HIV infection. The retinochoroiditis and vitritis improved after an antitoxoplasmic regimen with trimethoprim-sulfamethoxazole (TMP-SMX). Nonetheless, toxoplasmic encephalitis developed 6 months after the onset of ocular toxoplasmosis and responded well to TMP-SMX. This is the first case of toxoplasmic retinochoroiditis as the initial manifestation of AIDS reported in Taiwan. We suggest that Toxoplasma infection should be included in the differential diagnosis of diffuse necrotizing retinochoroiditis and vitritis. We also recommend that adults with newly diagnosed ocular toxoplasmosis be screened for HIV infection.

Convergence of two repressors through heterodimer formation of androgen receptor and testicular orphan receptor-4: a unique signaling pathway in the steroid receptor superfamily

The androgen receptor (AR) binds to androgen response elements and regulates target genes via a mechanism involving coregulators. Here we demonstrate that the AR can interact with the testicular orphan receptor-4 (TR4) and function as a repressor to down-regulate the TR4 target genes by preventing the TR4 binding to its target DNA. Interestingly, the heterodimerization of AR and TR4 also allows TR4 to repress AR target gene expression. Simultaneous exposure to both receptors therefore could result in bidirectional suppression of their target genes. Together, these data demonstrate that the coupling of two different receptors, through the heterodimerization of AR and TR4, is a unique signaling pathway in the steroid receptor superfamily, which may facilitate further understanding of the complicated androgen action in prostate cancer or libido.

Differential regulation of direct repeat 3 vitamin D3 and direct repeat 4 thyroid hormone signaling pathways by the human TR4 orphan receptor

In situ hybridization analysis demonstrated that abundant testicular orphan receptor (TR4) transcripts were detected in kidney, intestine, and bone, which are vitamin D3 target organs. Cell transfection studies also demonstrated that the expression of the vitamin D3 target gene, 25-hydroxyvitamin D3 24-hydroxylase, can be repressed by TR4 through high affinity binding (Kd = 1.32 nM) to the direct repeat 3 vitamin D3 receptor response element (DR3VDRE). This TR4-mediated repression of DR3VDRE is in contrast to our earlier report that TR4 could induce thyroid hormone target genes containing a direct repeat 4 thyroid hormone response element (DR4T3RE). Electrophoretic mobility shift assay using several TR4 monoclonal antibodies when combined with either TR4-DR3VDRE or TR4-DR4T3RE showed a distinct supershifted pattern, and proteolytic analysis further demonstrated distinct digested peptides with either TR4-DR3VDRE or TR4-DR4T3RE. These results may therefore suggest that TR4 can adapt to different conformations once bound to DR3VDRE or DR4T3RE. The consequence of these different conformations of TR4-DR3VDRE and TR4-DR4T3RE may allow each of them to recruit different coregulators. The differential repression of TR4-mediated DR3VDRE and DR4T3RE transactivation by the receptor interacting protein 140, a TR4 coregulator, further strengthens our hypothesis that the specificity of gene regulation by TR4 can be modulated by protein-DNA and protein-protein interactions.

Identification of the histamine H1 receptor gene as a differentially repressed target of the human TR2 orphan receptor

We have identified a DNA response element (TR2RE-HR) in the 3' flanking region of the human histamine H1 receptor gene as a target for the TR2 orphan receptor, a member of the steroid/thyroid hormone receptor superfamily. The application of both tetracycline inducible and improved differential display systems has allowed us to isolate a cDNA fragment differentially regulated by the expression of the TR2 orphan receptor. Northern blot and sequencing analysis demonstrated that the expression of the human histamine H1 receptor gene was differentially repressed by the TR2 orphan receptor. Electrophoretic mobility shift assay further revealed a specific binding (dissociation constant = 26.2 nM) between the TR2 orphan receptor and the wildtype TR2RE-HR, but not the mutant TR2RE-HR. In addition, reporter gene expression assay indicated that the TR2 orphan receptor may suppress the expression of luciferase activities in a dose-dependent manner via the TR2RE-HR in HeLa cells. Our results demonstrate that the histamine H1 receptor gene could represent one of the target genes directly regulated by the human TR2 orphan receptor.

Induction of TR4 orphan receptor by retinoic acid in human HaCaT keratinocytes

Human TR4 orphan receptor (TR4) can modulate the transcriptional activity of the reporter gene containing an AGGTCA direct repeat-hormone response element. Here we studied the potential role of TR4 in human HaCaT keratinocytes. Using a chloramphenicol acetyl-transferase reporter gene assay, it was shown that TR4 can suppress retinoic acid-induced transactivation by 47.3% in human HaCaT keratinocytes. Electrophoretic mobility shift assay indicated that this suppression may be due to TR4 binding with higher affinity to the retinoic acid response element than retinoid receptors. Western blot analysis further suggested that retinoic acid can increase the expression of TR4 protein in human HaCaT keratinocytes, indicating that TR4 acts as a negative feedback modulator for retinoic acid action. Interestingly, TR4 expression is increased in normal human keratinocytes when substituting a low calcium medium with a high calcium medium. Together, our data suggested, for the first time, that an orphan receptor, such as TR4, may play an important part in retinoid-mediated signaling pathways in human keratinocytes, providing a new insight into keratinocyte biology.

A bidirectional regulation between the TR2/TR4 orphan receptors (TR2/TR4) and the ciliary neurotrophic factor (CNTF) signaling pathway

Previously, we reported that the nuclear orphan receptor TR4 could induce transcriptional activity via the 5th intron of the ciliary neurotrophic factor (CNTF) alpha receptor gene (CNTFR-I5). Here we show CNTF could increase TR4 expression and enhance the DNA-binding capacity of TR4. Interestingly, the expression of TR2, a close family member of TR4, could also be induced by CNTF. In return, TR2 induced CNTFRalpha transcriptional activity through binding to a direct repeat response element of AGGTCA within CNTFR-I5. The possibility of this mutual influence between TR2 and the CNTF signaling was further strengthened by in situ hybridization. Similar expression patterns of TR2 and CNTFRalpha were observed in most of the developing neural structures such as the ganglia, neural epithelia, spinal cord, and the periventricular areas of brain. Together, our data suggest that an interaction between TR2/TR4 and the CNTF signaling pathway may occur, supporting the hypothesis that TR2/TR4 may play important roles in neurogenesis.

Undiagnosed acute myocardial infarction in the accident and emergency department: reasons and implications

Because acute myocardial infarction causes significant morbidity and mortality, a correct diagnosis in the accident and emergency department is important so that early treatment including thrombolytic therapy can be given. The aim of this study was to evaluate the reasons for missed diagnosis of acute myocardial infarction in the accident and emergency department, and the implications. All patients admitted to our coronary care unit in 1995 with the confirmed diagnosis of acute myocardial infarction were analysed retrospectively. The demographic data, clinical profiles, diagnosis made at the accident and emergency department and feasibility of thrombolytic therapy were assessed. Analysis of the electrocardiography by the accident and emergency department doctor and the coronary care unit doctor were also compared. Forty-three out of 159 patients (27.0%) with acute myocardial infarction were missed in the accident and emergency department. The diagnoses made were mostly angina or chest pain. Absence of chest pain (25.6%) [vs. 10.2% in correct diagnosis group, p < 0.05] and lack of ST elevation in electrocardiograph (62.8%) [vs. 18.1% in correct diagnosis group, p < 0.0001] were the main predisposing factors for missed diagnosis. Because of missed diagnosis, only 25.6% (vs. 67.2% in correct diagnosis group, p < 0.01) of patients were admitted to the coronary care unit. About one-third (34.9%) of missed diagnosis patients (vs. 6.0% in correct diagnosis, p < 0.01) did not receive thrombolytic therapy because of delayed diagnosis. In the missed diagnosis group, 34.8% of them might be avoidable, if electrocardiogram interpretation was more accurate. More education and training of the involved medical personnel might improve the overall situation.

Negative feedback control of the retinoid-retinoic acid/retinoid X receptor pathway by the human TR4 orphan receptor, a member of the steroid receptor superfamily

Amino acid sequence analysis indicates that the human TR4 orphan receptor (TR4) is a member of the estrogen/thyroid receptor subfamily of the steroid/thyroid receptor superfamily and recognizes the AGGTCA direct repeat (DR) of the hormone response element. Here we demonstrate using the electrophoretic mobility shift assay that TR4 binds specifically to DR with a spacing of 1 and 5 base pairs (DR1 and DR5), which are the response elements for retinoic acid receptor (RAR) and retinoid X receptor (RXR), respectively. A reporter gene assay using chloramphenicol acetyltransferase demonstrated that TR4 repressed RA-induced transactivation in a TR4 dose-dependent manner. Inhibition of the retinoid signal pathway also occurs through natural response elements found in CRBPII and RARbeta genes. Our data suggest that the mechanism of repression may not involve the formation of functionally inactive heterodimers between TR4 and RAR or RXR. Instead, we show that TR4 may compete for hormone response elements with RAR and RXR due to its higher binding affinity. Furthermore, treatment of F9 murine teratocarcinoma (F9) cells with 10(-6) M all-trans-retinoic acid increased TR4 mRNA levels, and this change was accompanied by an increased amount of endogenous TR4 protein that can bind to RXRE in electrophoretic mobility shift assay. Our data therefore strongly suggest that the retinoid signal pathway can be regulated by TR4 in a negative feedback control mechanism, which may restrict retinoic acid signaling to certain elements in a cell-specific fashion.

A stage-of-change classification system based on actions and beliefs regarding dietary fat and fiber

PURPOSE

The objectives of this study were to develop a stage-of-change classification system and to determine the degree to which various adult subgroups have adopted the behavioral changes necessary to achieve a low-fat and/or high-fiber diet as recommended by the Dietary Guidelines for Americans.

DESIGN

The study used a mail survey randomly sent to 7110 adults.

SETTING

The survey was conducted in 11 states and the District of Columbia.

SUBJECTS

The random sample included males and females over age 18. Of the eligible respondents, 3198 (51.5%) were included in this analysis, with 2004 and 2066 unambiguously classified into stages of change for fat and fiber, respectively.

MEASURES

Stage of change was defined by an algorithm based on self-reported intent and behaviors to limit fat and/or increase fiber.

RESULTS

45% of the respondents were classified as being in action/maintenance for fat and 38% for fiber. Women, older adults, individuals with advanced education, persons with diet-related chronic disease, people with higher levels of relevant nutrition knowledge and attitudes, and persons who indicated that health concerns were a primary influence on their diet were more likely to be in action/maintenance than other respondents.

CONCLUSIONS

The algorithm in this study presents a model that more closely reflects the proportions of the adult population that have achieved low-fat diets and classifies a greater proportion in the preparation stage than classification systems in previous studies.

Identification of the human aldolase A gene as the first induced target for the TR2 orphan receptor, a member of the steroid hormone receptor superfamily

The human TR2 orphan receptor (TR2) is a member of the steroid/thyroid hormone receptor superfamily that regulates the transcription of complex gene networks and subsequently controls diverse aspects of growth, development, and differentiation. In the present study, we have found that the TR2 is one of the M1 site (nucleotide numbers 2017-2034, 5'-AAAAGGGCAGGGGTCATT-3') binding proteins of the muscle-specific pM promoter in the human aldolase A gene. Electrophoretic mobility shift assay (EMSA) showed a specific binding with high affinity (dissociation constant = 4.6 nM) between the TR2 and the M1 element. Circular permutation assay revealed a localized DNA flexibility induced by the TR2 binding, and the bend angle was estimated to be 73 +/- 2 degrees. Furthermore, a dual-luciferase reporter gene assay demonstrated that the TR2 may enhance the expression of luciferase activities via the wild-type M1 site but not the mutant M1 element in human QM7 muscle myoblasts. In conclusion, our data represent the first case of demonstrating that the TR2 may serve as a transcriptional inducer in muscle-specific aldolase A gene expression.

Identification of direct repeat 4 as a positive regulatory element for the human TR4 orphan receptor. A modulator for the thyroid hormone target genes

While the TR4 orphan receptor (TR4) is able to repress the expression of its target genes via its interaction with the direct repeat 1-hormone response element (DR1-HRE) and DR2-HRE, we now report that TR4 can also induce the transcriptional activity of the reporter gene containing a DR4-HRE via chloramphenicol acetyltransferase assay. Electrophoretic mobility shift assay and Scatchard analysis reveal a strong binding affinity (dissociation constant = 2 nM) between TR4 and DR4-HRE. The induction mediated by TR4 was detected not only in the synthetic DR4-HRE but also in some genes, such as rat alpha-myosin heavy-chain and S14 genes, containing the DR4 or DR4-like motif, which have been suggested to be the response elements for a thyroid hormone receptor. Our data also demonstrate this TR4-mediated gene induction is TR4 dose- and DR4 sequence-dependent. Together, our data suggest that DR4-HRE can be a positive regulatory element for TR4, which may be able to induce the transcriptional activity of the genes containing such positive HREs.

Total knee arthroplasty in rheumatoid arthritis. A comparison of the polycentric and total condylar prostheses

From 1971 to 1985, 393 total knee arthroplasties (TKAs) were performed in patients for rheumatoid arthritis. Of these, 112 used polycentric prostheses and 131 used total condylar prostheses. One hundred seven of the patients with polycentric prostheses and 102 of the patients with total condylar prostheses were followed for a minimum of two years (average, 61 and 55 months, respectively). At the time of the latest examination, nine knees with polycentric prostheses required revision surgery: six for tibial component loosening and instability and three for patellofemoral pain. Five knees with total condylar prostheses required revision: one for chronic instability, one for a late posttraumatic patellar fracture, and three for late hematogenous infections. The total condylar prostheses with patellar resurfacing had better scores for pain (8.5 points) than the polycentric prosthesis without patellofemoral resurfacing (7.0 points). The total condylar prosthesis appeared more durable in terms of fixation, with no evidence of aseptic loosening of femoral or tibial components noted in this series thus far.

Intramuscular deltoid pressure during shoulder arthroscopy

A large amount of fluid extravasation into the surrounding muscle and soft tissue may occur during arthroscopy of the shoulder and particularly of the subacromial space. The tense swollen appearance of the shoulder has caused concern that the intramuscular deltoid pressure may become elevated to dangerous levels. Therefore, the intramuscular deltoid pressure was monitored in this study using a slit catheter. Although it was found that the intramuscular pressure became transiently elevated during the arthroscopic procedures, in every case the pressures promptly returned to normal levels within 30 min postoperatively. The clinical swelling and tenseness remained for a longer period. Despite a sometimes alarming amount of swelling during shoulder arthroscopy, intramuscular pressure elevations were only sustained for a short time and returned to normal levels very quickly after the cessation of fluid infusion.

Management of chronic exertional anterior compartment syndrome of the lower extremity

Eighteen patients (28 compartments) with chronic exertional compartment syndrome and 14 normal asymptomatic volunteers (18 compartments) were studied. Evaluation included clinical assessment followed by quantitative determination of intracompartmental pressures as monitored by wick or slit catheters before and after exercise. Intramuscular pressures measuring greater than or equal to 10 mmHg at rest and/or greater than or equal to 25 mmHg five minutes after exercise were defined as abnormally elevated. The patients with chronic compartment syndrome described reproducible exertional anterolateral leg pain, and 39% of these patients had a fascial hernia. Such a defect was present in less than five percent of the normal volunteers. Nonsurgical treatment was selected by five patients and all five reported persistent inability to participate in athletics because of their exertional pain. Of the remaining 13 patients, 12 were treated by decompressive fasciotomy and 11 of the 12 (92%) had pain relief and increased exercise tolerance. A single patient had had fascial closure instead of fasciotomy, and this procedure produced an acute compartment syndrome. Effective treatment of the chronic compartment syndrome consists of reduction of exertional activities or surgical decompression by fasciotomy.

Fracture of the tibia complicated by acute compartment syndrome

A consecutive series of 32 patients with tibia fractures complicated by compartment syndrome was treated with fasciotomy. One group was also treated with closed reduction of the fracture and cast immobilization and compared with a comparable group treated with internal fixation without case immobilization after fasciotomy. All other patients were treated with fasciotomy and reduction followed with either external skeletal fixation, pins and plaster, or skeletal traction. Care of the open fasciotomy incisions, observation of the neurovascular status of the limb, and rehabilitation of the extremity were facilitated by internal fixation operations without subsequent external cast immobilization. The anatomic and functional results in this group were better than those treated with fasciotomy and cast immobilization. All fractures were united by 20 weeks. Complications in both groups were similar, although one deep infection, which was resolved with appropriate treatment, occurred in the group treated with internal fixation. Six open tibia fractures were treated with external skeletal fixation after fasciotomy; the results were less satisfactory, but the initial injuries were also more severe in this group. Patients with closed tibial fractures complicated by compartment syndromes should be treated expeditiously with fasciotomy, followed by stable internal fixation.

Development of a specific radioimmunoassay for cortisol 17-butyrate

We describe the development and validation of an assay for cortisol 17-butyrate in blood in which there is no significant cross reaction with endogenous corticosteroids at levels encountered normally in man. Preliminary data on blood levels of the drug in absorption studies are presented.

The questionable significance of hip joint tamponade in producing osteonecrosis in Legg-Calvé-Perthes syndrome

A possible mechanism for development of Legg-Calvé-Perthes syndrome following transient synovitis is the production of an effusion which acts as a tamponade of the intracapsular, subsynovial vessels to the femoral capital epiphysis. An intraarticular pressure of 150-200 mm Hg continuing for 10 to 12 h has been required to produce epiphyseal ischemia and subsequent osteonecrosis in animals. This study, on the hip of the immature pig, showed that an induced talcum synovitis did not increase intraarticular pressure. Autologous plasma was infused into synovitis-affected and normal hips to raise intraarticular pressures to 50, 100, and 200 mm Hg, respectively, in three groups of pigs. Decay of these joint pressures to 35 mm Hg occurred within a maximum of 132 min. This period is much less than the ischemia time required to cause osteocyte death. Decay of intraarticular pressure resulted from capsular stretching and efflux of the infusate from the joint. The data from this experiment do not support the theory that tamponade of the femoral capital epiphysis is the cause of osteonecrosis in Legg-Calvé-Perthes syndrome.

Axonal growth in mesothelial chambers. The role of the distal nerve segment

An experimental model is presented for studying nerve regeneration over gaps of various lengths between the both ends of a severed nerve. After transferring left and right sciatic nerves of rat to the back, the gap between the two nerve ends could be bridged by a preformed, tube-shaped mesothelial chamber of a desired length. When the gap length was 10 mm or less, a well developed nerve structure was generated in the chamber between the nerve ends, and axons from the left sciatic nerve reinnervated muscles in the right limb via the right sciatic nerve. When the gap length was extended to 15 mm or more no such regeneration occurred. When no distal nerve end was introduced into the chamber, there was a limited growth into this chamber over only 5-6 mm. This "limited growth phenomenon" is discussed with respect to a lack of "trophic" or cellular support from a distal nerve segment. It is also proposed that the termination of growth, seen under these circumstances, may suggest a new principle for avoiding the development of neuromas after nerve transections.

The medial tibial stress syndrome. A cause of shin splints

The medial tibial stress syndrome is a symptom complex seen in athletes who complain of exercise-induced pain along the distal posterior-medial aspect of the tibia. Intramuscular pressures within the posterior compartments of the leg were measured in 12 patients with this disorder. These pressures were not elevated and therefore this syndrome is a not a compartment syndrome. Available information suggests that the medial tibial stress syndrome most likely represents a periostitis at this location of the leg.

Median nerve compression in the carpal tunnel--functional response to experimentally induced controlled pressure

Controlled external compression was applied to the medium nerve of 16 volunteer subjects. Tissue fluid pressure in the carpal canal was monitored with a wick catheter and pressures of 30, 60 and 90 mm Hg were induced for periods varying from 30 to 90 minutes.l Sensory and motor conduction and two-point discrimination were continuously monitored. Tissue compression at 30 mm Hg caused mild neurophysiological changes and symptoms of hand paresthesias. Compression at both 60 and 90 mm Hg induced a rapid, complete sensory conduction block which consistently preceded a motor block by 10 to 30 minutes. Frequently, two-point discrimination remained normal until the last stages of preserved sensory fiber conduction. In three cases, a modification of the model utilizing an arm tourniquet, demonstrated that ischemia rather than mechanical deformation was the primary cause of the functional deterioration. It was concluded that there is a critical pressure level between 30 and 60 mm Hg where nerve fiber viability is acutely jeopardized.

Sequence studies of poliovirus RNA. IV. Nucleotide sequence complexities of poliovirus type 1, type 2 and two type 1 defective interfering particles RNAs, and fingerprint of the poliovirus type 3 genome

The 32P-labelled genomes of poliovirus type 1, 2 and 3 have been digested with RNase T1 and the products separated by two-dimensional gel electrophoresis. All three fingerprints differ in the separation pattern of the large oligonucleotides. The molar yields of the large RNase T1-resistant oligonucleotides of type 1 and type 2 RNA of poliovirus RNA are close to one. By comparing the yields of these oligonucleotides to the amount of RNA from which they originated, the chain length of type 1 poliovirus RNA was found to be 7851 +/- 567 nucleotides (mol. wt. 2.66 +/- 0.19 x 10(6) and that of poliovirus type 2, 8181 +/- 578 nucleotides (mol. wt. 2.77 +/- 0.19 x 10(6). The chain length of two defective interfering particle (DI) RNAs of poliovirus type 1 were determined to be 7042 +/- 999 nucleotides for DI(1) and 6639 +/- 674 nucleotides for DI(2).

A protein covalently linked to poliovirus genome RNA

Poliovirion [32P]RNA, after digestion with RNase T2, yields mononucleotides and a labeled compound "X," which is not negatively charged at pH 5. X contains, relative to the label in virion RNA, one to two phosphates and is partially acid insoluble. It can be labeled with tritiated amino acids 3 hr after infection, is insoluble in chloroform/methanol, and can be digested with Pronase. These observations suggest that X is a protein. The protein cannot be removed from the polio genome when the RNA is (i) sedimented through a sucrose gradient in 0.5 M NaCl, (ii) heated to 100 degrees in the presence of sodium dodecyl sulfate followed by sedimentation through a sucrose gradient in 80% dimethylsulfoxide, or (iii) banded in 4 M cesium trichloroacetate. Digestion of the 32P-labeled protein with Pronase yields one major 32P-labeled product, which contains pUp. The protein migrates faster than capsid protein VP4 in a polyacrylamide gel. Our data show that the genome of poliovirus, but not poliovirus mRNA [A. Nomoto, Y. F. Lee, and E. Wimmer (1976) Proc. Natl. Acad. Sci. USA 73, 375-380], is covalently attached to a small virus-coded protein (molecular weight less than 7000), which we call VPg. VPg is probably linked to the 5' end of the polio genome. Possible functions of VPg in viral replication are discussed.

"Fingerprinting" high molecular weight RNA by two-dimensional gel electrophoresis: application to poliovirus RNA

Conditions are described under which complete RNase T1 digests of high molecular weight RNA can be separated into numerous components by two-dimensional gel electrophoresis. Small and large oligonucleotides (n = 1 - 2c0) can be resolved without losses. The procedure yields fingerprints which are diagnostic for a particular species of RNA and an index of its purity as will be shown for the genomes of poliovirus type 1 and 2.

The 5' end of poliovirus mRNA is not capped with m7G(5')ppp(5')Np

Poliovirus was grown in HeLa cells in the presence of phosphorus-32 and actinomycin D. Three to four hours after infection, viral mRNA was recovered from polyribosomes and its identity verified by two-dimensional gel electrophoresis of RNase T1 digests. Digestion of the viral [32P]mRNA with RNase T2 and separation of the products by ion exchange chromatography at pH 5 yielded pUp as possible 5' terminus but no "capping group" of the structure m7G(5')ppp(5')Np. Total cytoplasmic [32P]RNA of HeLa cells, on the other hand, was found to contain capping groups. Neither the capping group nor ppNp or pppNp was found in an RNase T2 digest of poliovirion [32P]RNA, in agreement with previous results [Wimmer, E. (1972) J. Mol. Biol. 68, 537-540]. The data indicate that 5'-terminal m7G(5')ppp(5')Np is absent from poliovirus RNAs and, therefore, is not involved in poliovirus protein synthesis.

A technique for the isolation of mutants of Escherichia coli affected in degradation of cellular RNA

Using a semiautomatic technique for handling large numbers of Escherichiacoli colonies, mutants that fail to digest their cellular RNA were isolated. This was achieved by using multiwell plates where each colony is cloned in an individual well. Cells labeled with a radioactive RNA precursor were starved for a carbon source at a high temperature. In order to assess whether or not degradation of cellular RNA took place, aliquots of each culture were subjected to autoradiography. A number of mutants defective in decay of RNA were isolated. One of them was characterized, and was found to be deficient specifically in the enzyme polynucleotide phosphorylase. Experiments carried out with this strain indicate that this enzyme participates in the degradation of "stable" RNA during carbon starvation.