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1.
Health Sci Rep ; 6(10): e1664, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37900092

ABSTRACT

Background and Aim: Frailty is a condition marked by accumulation of biological deficits and dysfunctions that come with aging and it is correlated with high morbidity and mortality in patients with cardiovascular diseases, particularly hypertension. Hypertension continues to be a leading cause of cardiovascular diseases and premature death globally. However, there is dearth of literature in sub-Saharan Africa on frailty syndrome among hypertensives on medication. This study evaluated frailty syndrome and its associated factors among Ghanaian hypertensives. Methods: This cross-sectional study recruited 303 patients with hypertension from the University Hospital, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana. Data on sociodemographic, lifestyle and clinical factors were collected using a well-structured questionnaire. Medication adherence was measured using Adherence in Chronic Disease Scale, and frailty was assessed by Tilburg Frailty Indicator. Statistical analyses were performed using SPSS Version 26.0 and GraphPad prism 8.0. p-value of < 0.05 and 95% confidence interval (CI) were considered statistically significant. Results: The prevalence of frailty was 59.7%. The proportion of high, medium and low medication adherence was 23.4%, 64.4% and 12.2%, respectively. Being ≥ 70years (adjusted odds ratio [aOR]: 8.33, 95% CI [3.72-18.67], p < 0.0001), unmarried (aOR: 2.59, 95% CI [1.37-4.89], p = 0.0030), having confirmed hypertension complications (aOR: 3.21, 95% CI [1.36-7.53], p = 0.0080), medium (aOR: 1.99, 95% CI [1.05-3.82], p = 0.0360) and low antihypertensive drug adherence (aOR: 27.69, 95% CI [7.05-108.69], p < 0.0001) were independent predictors of increased odds of developing frailty syndrome. Conclusion: Approximately 6 out of 10 Ghanaian adult patients with hypertension experience frailty syndrome. Hypertension complications, older age, being unmarried, and low antihypertensive drug adherence increased the chances of developing frailty syndrome. These should be considered in intervention programmes to prevent frailty among patients with hypertension.

2.
J Laryngol Otol ; 136(9): 839-847, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35606901

ABSTRACT

OBJECTIVE: This study aimed to determine the implications of including tympanometry in the Rapid Assessment of Hearing Loss survey protocol. A comparative study design was employed, with findings from otoscopy compared with the results of tympanometry. METHOD: A population-based survey of the prevalence and causes of hearing loss among adults aged over 35 years in The Gambia was conducted. Clinical assessments included air conduction audiometry, otoscopy and clinical history. Otoscopy outcome was recorded and for those with hearing loss, a probable cause was assigned. Following otoscopy, tympanometry was completed. Otoscopy outcome was not changed as a result of tympanometry. Clinician assigned cause was compared to the results of tympanometry. The proportion of causes potentially misclassified by excluding tympanometry was determined. RESULTS: Among people with hearing loss, including tympanometry led to a higher proportion diagnosed with middle-ear conditions. CONCLUSION: The value of adding tympanometry to population-based survey protocols is a higher estimated proportion of hearing loss being attributed to middle-ear disease rather than sensorineural causes. This can inform service needs as more people will be classified as needing medical or surgical services, and a slightly lower number will need rehabilitative services, such as hearing assistive devices. It is highly recommended that tympanometry is included in the protocol.


Subject(s)
Deafness , Hearing Loss , Acoustic Impedance Tests/methods , Adult , Audiometry , Hearing Loss/diagnosis , Hearing Loss/epidemiology , Humans , Otoscopy/methods , Prevalence
3.
Ghana Med J ; 56(4): 239-245, 2022 Dec.
Article in English | MEDLINE | ID: mdl-37575629

ABSTRACT

Objective: The study assessed willingness to accept the COVID-19 vaccine among out-patient department (OPD) attendants in the Bono Region in Ghana. Design: This was an analytical cross-sectional study. Setting: The study was conducted at the Wenchi Methodist Hospital (WMH) OPD, Bono Region, Ghana. The region had not yet been earmarked for vaccination at the time of the study. Participants: Three hundred and twenty-five (325) participants aged ≥18 years, accessing care at the OPD of WMH and willing to give informed consent, were interviewed. Main outcome measures: The proportion of participants willing to accept the COVID-19 vaccine and its determinants. Results: Of 325 participants interviewed, 32 (9.8%) had been vaccinated already. 82.6% (242/293) indicated COVID-19 vaccine acceptance among the unvaccinated. The major reason for vaccine acceptance was "it could protect against COVID-19" (96.7%, 234/242). "Fear of vaccine side effects and "perception of not being susceptible to COVID-19" were among the reasons for vaccine refusal. Perceived susceptibility to COVID-19 (AOR 4.09, 95% CI 1.79, 9.34), knowledge of COVID-19 and COVID-19 vaccine (AOR 3.62, 95% CI 1.14, 11.46) and willingness to pay for the vaccine (AOR 5.20, 95% CI 2.49, 10.43) were associated with vaccine acceptance. Conclusions: Adequate knowledge of COVID-19 and the vaccine may drive vaccine acceptance in the study area and possibly other areas in Ghana. Campaign messages aimed at increasing COVID-19 vaccine coverage must emphasise its safety, likely side effects and management in order to help rid the population of misconceptions. Funding: None indicated.


Subject(s)
COVID-19 , Drug-Related Side Effects and Adverse Reactions , Humans , Adolescent , Adult , COVID-19 Vaccines , COVID-19/epidemiology , COVID-19/prevention & control , Ghana , Cross-Sectional Studies
4.
Ghana med. j ; 56(4): 239-245, 2022. tables
Article in English | AIM (Africa) | ID: biblio-1401980

ABSTRACT

Objective: The study assessed willingness to accept the COVID-19 vaccine among out-patient department (OPD) attendants in the Bono Region in Ghana. Design: This was an analytical cross-sectional study Setting: The study was conducted at the Wenchi Methodist Hospital (WMH) OPD, Bono Region, Ghana. The region had not yet been earmarked for vaccination at the time of the study. Participants: Three hundred and twenty-five (325) participants aged ≥18 years, accessing care at the OPD of WMH and willing to give informed consent, were interviewed.Main outcome measures: The proportion of participants willing to accept the COVID-19 vaccine and its determinants. Results: Of 325 participants interviewed, 32 (9.8%) had been vaccinated already. 82.6% (242/293) indicated COVID19 vaccine acceptance among the unvaccinated. The major reason for vaccine acceptance was "it could protect against COVID-19" (96.7%, 234/242). "Fear of vaccine side effects and "perception of not being susceptible to COVID-19" were among the reasons for vaccine refusal. Perceived susceptibility to COVID-19 (AOR 4.09, 95% CI 1.79, 9.34), knowledge of COVID-19 and COVID-19 vaccine (AOR 3.62, 95% CI 1.14, 11.46) and willingness to pay for the vaccine (AOR 5.20, 95% CI 2.49, 10.43) were associated with vaccine acceptance. Conclusions: Adequate knowledge of COVID-19 and the vaccine may drive vaccine acceptance in the study area and possibly other areas in Ghana. Campaign messages aimed at increasing COVID-19 vaccine coverage must emphasise its safety, likely side effects and management in order to help rid the population of misconceptions


Subject(s)
Humans , Epidemiologic Factors , COVID-19 , Behavior , Bacterial Vaccines , Ghana
6.
World J Surg ; 43(12): 3065-3073, 2019 12.
Article in English | MEDLINE | ID: mdl-31485811

ABSTRACT

BACKGROUND: Flatulence is known to be a common side effect of laparoscopic fundoplication, yet the true incidence is unclear and its impact on patients' quality of life not well understood. This study aimed to assess the long-term incidence of flatulence, and its effect on quality of life, following fundoplication. METHODS: All patients who underwent primary laparoscopic fundoplication between 1999 and 2009 were identified from a prospectively maintained institutional database. A cross-sectional analysis of post-operative gastrointestinal symptoms and quality of life was performed using a symptom-specific questionnaire. Statistical analysis of outcomes stratified by sex and type of fundoplication was performed. RESULTS: 462 eligible patients were identified from the database, with follow-up obtained in 265 (57%). Median age at surgery was 53 (22-78) years. 137 patients (52%) were female. 138 (52%) underwent a 360° fundoplication, the remainder a partial fundoplication. At median follow-up of 11 (8-15) years, excessive flatulence was reported by 85%. Only 12% reported an adverse impact on social life, and 11% an adverse impact on quality of life. Flatulence was worse following a total than partial fundoplication, women reported more gas-related symptoms than men, yet neither sex nor wrap type had a significant impact on social life or quality of life. CONCLUSIONS: The majority of patients report excessive flatulence at long-term follow-up after anti-reflux surgery, yet the impact on social life and quality life was small. There was no evidence to support tailoring of wrap type by sex to avoid gas-related symptoms. The authors advocate that all patients understand the inevitable side effects of fundoplication to help manage expectations from surgery.


Subject(s)
Flatulence/etiology , Fundoplication/adverse effects , Gastroesophageal Reflux/surgery , Postoperative Complications , Adult , Aged , Cross-Sectional Studies , Esophagitis, Peptic/etiology , Female , Follow-Up Studies , Fundoplication/methods , Fundoplication/rehabilitation , Humans , Incidence , Laparoscopy/adverse effects , Male , Middle Aged , Quality of Life , Radiography, Abdominal , Risk Factors , Severity of Illness Index , Sex Factors , Surveys and Questionnaires , Treatment Outcome , Young Adult
7.
ACS Omega ; 4(2): 2510-2516, 2019 Feb 28.
Article in English | MEDLINE | ID: mdl-31459489

ABSTRACT

We disclose in this study a Ni6AlO x catalyst prepared by coprecipitation for the reductive amination of biomass-derived aldehydes and ketones in aqueous ammonia under mild reaction conditions. The catalyst exhibited 99% yield toward 5-aminomethyl-2-furylmethanol in the reaction of 5-hydroxymethyl furfural with ammonia at 100 °C for 6 h under 1 bar H2. The catalyst was further extended to the reductive amination of a library of aromatic and aliphatic aldehydes and ketones with a yield in the range 81-90% at optimized reaction conditions. Besides, 5-hydroxymethylfurfural could react with a library of primary and secondary amines with yields in the range 76-88%. The catalyst could be easily recycled and reused without apparent loss of activity in four consecutive runs.

8.
RSC Adv ; 9(66): 38877-38881, 2019 Nov 25.
Article in English | MEDLINE | ID: mdl-35540204

ABSTRACT

The development of facile protocols for the selective synthesis of biomass-derived diamine is a highly desirable pursuit in the field of heterogeneous catalysis. Herein, a simple and highly efficient bi-functional CuNiAlO x catalyst was developed for the one pot transformation of 5-(hydroxymethyl)furfural (5-HMF) into 2,5-bis(aminomethyl)furan (BAF) using a two-stage reaction process. Cu4Ni1Al4O x was found to be the most effective catalyst for this reaction, affording BAF in 85.9% yield. Our results could promote controllable conversion and utilization of biomass resource.

9.
Dis Esophagus ; 30(2): 1-7, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27878904

ABSTRACT

There is a well-established link between cancer and venous thromboembolism (VTE), and patients receiving chemotherapy for esophageal or gastric cancer appear at high risk of developing VTE. The incidence of VTE in the neoadjuvant setting in these patients is poorly understood, as is the role for thromboprophylaxis during neoadjuvant chemotherapy. A PubMed search was conducted using a combination of terms including; esophageal & gastric cancer, deep venous thrombosis (DVT), VTE, neoadjuvant, chemotherapy and chemoradiotherapy. One hundred and fifty-four articles were retrieved and a narrative review was conducted. For patients with esophageal and gastric cancer the incidence of VTE ranged from 4 to 19%. Gastric cancer (Odds Ratio [OR] 6.38, [95% CI: 1.96-20.80]) and Stage III/IV disease, (OR 5.16 [95% CI: 1.29-20.73]) were identified as risk factors for developing VTE. Neoadjuvant chemotherapy was identified as an independent risk factor for developing VTE. Symptomatic and asymptomatic VTE have a similar effect on mortality. Median overall survival for asymptomatic VTE was 13.9 months (95% CI: 5.0-∞) versus 12.8 months (95% CI: 4.7-30.3) if the VTE was symptomatic. Neoadjuvant chemotherapy is a significant risk factor for VTE in patients with esophageal and gastric cancer. Intervention to minimize the risk using pharmacological and mechanical thromboprophylaxis should be considered, and this should start in the neoadjuvant period.


Subject(s)
Chemotherapy, Adjuvant/adverse effects , Esophageal Neoplasms/drug therapy , Neoadjuvant Therapy/adverse effects , Stomach Neoplasms/drug therapy , Venous Thromboembolism/chemically induced , Adult , Aged , Female , Humans , Incidence , Male , Middle Aged , Risk Factors , Venous Thromboembolism/epidemiology
11.
Opt Express ; 22 Suppl 4: A1112-27, 2014 Jun 30.
Article in English | MEDLINE | ID: mdl-24978074

ABSTRACT

Metallodielectric photonic crystals having hyperbolic dispersions are called indefinite materials because of their ability to guide modes with extremely large lateral wavevectors. While this is useful for enhancing near-field radiative heat transfer, it could also give rise to large lateral displacements of the energy pathways. The energy streamlines can be used to depict the flow of electromagnetic energy through a structure when wave propagation does not follow ray optics. We obtain the energy streamlines through two semi-infinite uniaxial anisotropic effective medium structures, separated by a small vacuum gap, using the Green functions and fluctuation-dissipation theorem. The lateral shifts are determined from the streamlines within two penetration depths. For hyperbolic modes, the predicted lateral shift can be several thousand times of the vacuum gap width.

12.
Appl Clin Inform ; 4(4): 618-35, 2013.
Article in English | MEDLINE | ID: mdl-24454586

ABSTRACT

BACKGROUND: Many informatics studies use content analysis to generate functional requirements for system development. Explication of this translational process from qualitative data to functional requirements can strengthen the understanding and scientific rigor when applying content analysis in informatics studies. OBJECTIVE: To describe a user-centered approach transforming emergent themes derived from focus group data into functional requirements for informatics solutions and to illustrate these methods to the development of an antibiotic clinical decision support system (CDS). METHODS: THE APPROACH CONSISTED OF FIVE STEPS: 1) identify unmet therapeutic planning information needs via Focus Group Study-I, 2) develop a coding framework of therapeutic planning themes to refine the domain scope to antibiotic therapeutic planning, 3) identify functional requirements of an antibiotic CDS system via Focus Group Study-II, 4) discover informatics solutions and functional requirements from coded data, and 5) determine the types of information needed to support the antibiotic CDS system and link with the identified informatics solutions and functional requirements. RESULTS: The coding framework for Focus Group Study-I revealed unmet therapeutic planning needs. Twelve subthemes emerged and were clustered into four themes; analysis indicated a need for an antibiotic CDS intervention. Focus Group Study-II included five types of information needs. Comments from the Barrier/Challenge to information access and Function/Feature themes produced three informatics solutions and 13 functional requirements of an antibiotic CDS system. Comments from the Patient, Institution, and Domain themes generated required data elements for each informatics solution. CONCLUSION: This study presents one example explicating content analysis of focus group data and the analysis process to functional requirements from narrative data. Illustration of this 5-step method was used to develop an antibiotic CDS system, resolving unmet antibiotic prescribing needs. As a reusable approach, these techniques can be refined and applied to resolve unmet information needs with informatics interventions in additional domains.


Subject(s)
Decision Support Systems, Clinical , Health Services Needs and Demand , Data Collection , Evaluation Studies as Topic , Humans , User-Computer Interface
13.
Colorectal Dis ; 7(1): 4-7, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15606577

ABSTRACT

The squeeze pressure in the anal canal reflects the contribution of the external anal sphincter and is normally assessed manometrically by asking patients to contract their anal muscles. However, this is an artificial situation as normally the external sphincter contracts to retain rectal content. Some patients with normal anal sphincter anatomy and innervation record low squeeze pressures suggesting that the concept of voluntary squeeze is foreign. The aim of this study was to examine whether squeezing to retain a balloon mimics the physiology of defaecation more accurately. Patients undergoing routine anorectal manometry testing had in addition the inflation of a balloon catheter to the volume of the first and sustained sensation to simulate a faecal bolus within the rectum. The patient was asked to retain it when the balloon was subjected to gentle traction, thus contracting their anal sphincter to prevent passage of the balloon. Squeeze pressure was measured in response to voluntary contraction, the pressure generated to retain the balloon, then voluntary contraction again. Eighteen women and 2 men were tested. The median maximal squeeze pressures with the routine assessment was 131.0 cmH2O. This increased to 210.0 cmH2O when the patients attempted to retain the balloon and fell to 165.4 cmH2O when patients were reassessed with voluntary squeeze postintervention. 15 of the patients improved their squeeze pressures with traction on the balloon. External anal sphincter contraction is difficult for some patients to perform on request. With traction on a balloon catheter anal squeeze pressures improved in most patients. This indicates that many patients perform maximal anal squeeze pressures better once that muscle group has been tested in a more normal physiological function. This simple technique could improve the accuracy of anorectal manometry results and evaluation in a larger population of symptomatic patients is warranted.


Subject(s)
Catheterization , Defecation/physiology , Manometry/instrumentation , Rectum/physiopathology , Adult , Aged , Aged, 80 and over , Constipation/diagnostic imaging , Constipation/physiopathology , Fecal Incontinence/diagnostic imaging , Fecal Incontinence/physiopathology , Female , Humans , Male , Middle Aged , Muscle Contraction/physiology , Prospective Studies , Reaction Time , Rectum/diagnostic imaging , Rectum/innervation , Ultrasonography
14.
Conf Proc IEEE Eng Med Biol Soc ; 2004: 3214-6, 2004.
Article in English | MEDLINE | ID: mdl-17270964

ABSTRACT

Recent litigation and the Master Settlement Agreement of 1998 have made millions of tobacco industry internal documents available on the Internet (http://legacy.library.ucsf.edu). The Legacy interface, housed at the University of California, San Francisco, is based on a traditional information retrieval model in which documents are indexed and retrieved based on user-specified queries. One problem with the Legacy interface is information overload. In an attempt to ease this problem, we are developing a text-mining interface to enable exploratory analysis and discovery of information from collections of data. Users could uncover new patterns and concepts and thus text mining could result in searches that are targeted and specific, which would decrease information overload. In order to determine information needs, nine in-depth interviews with regular users of the Legacy interface were conducted. Results show that participants identified clustering as a useful tool in identifying and extracting key concepts and identified the need to recognize relationships between terms and concepts within the data. We encourage researchers who are developing text-mining interfaces to survey the users to learn what particular aspects of their research could be enhanced by text mining.

15.
Clin Infect Dis ; 33(12): E145-7, 2001 Dec 15.
Article in English | MEDLINE | ID: mdl-11702293

ABSTRACT

We describe a 50-year-old man who presented with multiple liver abscesses that suggested biliary sepsis or portal pyemia. A wet preparation of a sample of aspirate showed the presence of amebic trophozoites, and subsequent serological testing for amebae was strongly reactive.


Subject(s)
Bile Duct Diseases/diagnosis , Liver Abscess, Amebic/diagnosis , Sepsis/diagnosis , Bile Duct Diseases/parasitology , Diagnosis, Differential , Humans , Liver Abscess, Amebic/epidemiology , Liver Abscess, Amebic/parasitology , Male , Middle Aged , North America/epidemiology , Sepsis/parasitology , Tomography, X-Ray Computed
17.
Pituitary ; 2(3): 217-24, 1999 Nov.
Article in English | MEDLINE | ID: mdl-11081157

ABSTRACT

Pit-1 is a transcription factor that appears early in embryonic pituitary gland formation and is necessary for the development of somatotropes, lactotropes and thyrotropes. Steroidogenic factor-1 (SF-1) is another early appearing transcription factor that is involved in the development of gonadotropes. In this study we have compared RT-PCR analysis of hormone mRNA with traditional IHC for classification of 27 pituitary tumors and have evaluated the correlation of Pit-1 and SF-1 mRNA with hormone mRNA. RT-PCR detected concordant hormone mRNA in 100% of GH IHC positive, 100% of PRL IHC positive, 33% of TSH IHC positive, and 93% of gonadotropin IHC positive tumors. IHC, however, was concordant in only 71% of GH mRNA positive, 78% of PRL mRNA positive, 17% of TSH beta mRNA positive, and 76% of FSH beta mRNA positive tumors. Pit-1 mRNA was positive in 87% of tumors in which mRNA for GH, PRL or TSH beta was detected and in only 17% of GH, PRL and TSH beta mRNA negative tumors. SF-1 mRNA was positive in 94% of tumors in which mRNA for FSH beta was present and in no FSH beta mRNA negative tumors. We conclude that RT-PCR analysis of hormone mRNA may be more sensitive than traditional hormone IHC for classification of pituitary tumors. Furthermore, tumor Pit-1 mRNA positively correlates with GH, PRL and TSH beta mRNA while tumor SF-1 mRNA correlates well with FSH beta mRNA. Combined analysis of hormone and transcription factor mRNA in pituitary tumor tissue may therefore be a more meaningful approach to pituitary tumor characterization.


Subject(s)
DNA-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic , Pituitary Hormones/genetics , Pituitary Neoplasms/genetics , Transcription Factors/genetics , DNA Primers , Follicle Stimulating Hormone/genetics , Fushi Tarazu Transcription Factors , Gonadotropins/genetics , Homeodomain Proteins , Humans , Immunohistochemistry , Pituitary Hormones/analysis , Pituitary Neoplasms/chemistry , Pituitary Neoplasms/classification , Prolactin/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Cytoplasmic and Nuclear , Reverse Transcriptase Polymerase Chain Reaction , Steroidogenic Factor 1 , Thyrotropin/genetics , Transcription Factor Pit-1
18.
Thyroid ; 7(3): 453-61, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9226219

ABSTRACT

The triiodothyronine (T3) inhibitory effect on the thyrotropin (TSH)beta- and alpha-subunit genes is believed to be mediated by binding of T3 to specific nuclear receptors that are present in various isoforms. alphaTSH cells, which are derived from a pure alpha-subunit secreting thyrotropic tumor, contain the same nuclear factors that are important for alpha-subunit gene expression in TSH-expressing T3-responsive thyrotropic cells (TtT97). However, as in the parent tumor, alpha-subunit expression in alphaTSH cells was not inhibited by T3, despite the presence of high-affinity nuclear T3 receptors (TRs) with a similar number of sites per cell as in TtT97. When transcripts coding for the different TR isoforms from the MGH101A tumor were analyzed by Northern blot, TR alpha1 was present, as well as the non-T3-binding variant alpha2, but transcripts encoding the opposite strand Rev-ErbAa were not detectable and neither TR beta1 nor TR beta2 mRNAs were detectable, whereas all these transcripts were detectable in TtT97 tumors. Similar findings were observed in alphaTSH cells, where TR beta1 transcripts were barely detectable in Northern blots and TR beta2 transcripts were detectable only by RT-PCR. The TR beta gene locus is present and unrearranged in the tumor genome. In transient transfection studies conducted in alphaTSH cells overexpression of either TR beta1, TR beta2, or TR alpha1 reconstituted T3-inhibition of the alpha-subunit promoter down to 40% to 50% of control. We conclude that the relative lack of TR beta gene expression correlates with unresponsiveness to T3. The alphaTSH cell line represents a unique model in which to dissect the mechanism of T3 inhibition.


Subject(s)
Receptors, Thyroid Hormone/metabolism , Thyroid Neoplasms/pathology , Triiodothyronine/pharmacology , Blotting, Northern , Blotting, Southern , Cell Nucleus/metabolism , Humans , Luciferases/metabolism , Plasmids , Polymerase Chain Reaction , Receptors, Thyroid Hormone/genetics , Thyroid Neoplasms/metabolism , Thyrotropin/metabolism , Transcription, Genetic , Transfection , Triiodothyronine/metabolism , Tumor Cells, Cultured
19.
J Biol Chem ; 271(39): 24213-20, 1996 Sep 27.
Article in English | MEDLINE | ID: mdl-8798664

ABSTRACT

There are three known thyroid hormone receptor (TR) isoforms that arise from two distinct alpha and beta gene loci. TRalpha1 and TRbeta1 mRNAs are found in many tissues, whereas mRNA for the N-terminal TRbeta2 variant derived from the beta locus is readily detectable only in the pituitary gland and derived cell sources such as GH3 somatotropes and TtT-97 thyrotropes. We previously isolated the genomic region governing expression of the TRbeta2 isoform in thyrotropes and showed that transcription arose from multiple origins within a 400-base pair (bp) region. We now report that the region extending 500 bp upstream of the putative AUG codon (A is +1) contains six areas of interaction with the pituitary-specific transcription factor Pit-1. In addition there are separate areas that bind other factors present in thyrotrope cells. Promoter deletions revealed that removal of regions containing the Pit-1 sites at -456 to -432, -149 to -127, and -124 to -102 progressively decreased TRbeta2 promoter activity in thyrotropes. A more proximal footprinted area from -65 to -19, which accounted for the remaining promoter activity, contained sites that interacted with recombinant Pit-1; however, extracts of TtT-97 thyrotropes, which express Pit-1, footprinted this proximal region with a pattern of protection that differed from that produced by Pit-1. A comparative deletional analysis demonstrated that a shorter region extending only 204 bp from the AUG was sufficient to support TRbeta2 promoter activity in GH3 somatotropes. The more proximal Pit-1 sites, including the area from -53 to -19, whose pattern differed from Pit-1 in thyrotrope extracts, showed protection patterns with GH3 extracts that were indistinguishable from recombinant Pit-1. Site-directed mutagenesis that abrogated binding of both recombinant Pit-1 and Pit-1-containing nuclear extracts revealed that the two Pit-1 sites between -149 and -102 were important for TRbeta2 promoter activity with the more proximal being most critical. Finally, we showed that TRbeta2 promoter activity in alpha-TSH cells, which do not transcribe the endogenous TRbeta2 locus or produce Pit-1 protein, could be reconstituted to a level approaching that seen in expressing TtT-97 thyrotropes by cotransfecting a Pit-1 expression vector. Activation by Pit-1 was dependent on the same Pit-1 sites shown to be important for basal TRbeta2 promoter activity in thyrotropes as constructs lacking them by deletion or mutation were not stimulated by Pit-1.


Subject(s)
DNA-Binding Proteins/physiology , Pituitary Gland/physiology , Promoter Regions, Genetic , Receptors, Thyroid Hormone/genetics , Transcription Factors/physiology , Animals , Base Sequence , Binding Sites , Cells, Cultured , Gene Expression Regulation , Male , Mice , Molecular Sequence Data , Rats , Sequence Deletion , Transcription Factor Pit-1 , Transcription, Genetic
20.
Mol Endocrinol ; 8(12): 1605-17, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7708051

ABSTRACT

beta 1 and beta 2 are functional thyroid hormone receptors (TRs) that are generated from the same genomic locus by splicing of a different amino terminus onto a common carboxyl region containing the DNA and hormone binding domains. TR beta 1 is widely expressed whereas TR beta 2 is found primarily in the pituitary gland although low levels of expression have been described in other tissues. To gain insight into the mechanisms governing expression of this complex transcriptional unit, we cloned mouse genomic fragments containing the common carboxyl terminus as well as the unique TR beta 2 amino-terminal sequence that was located at least 25 kilobases upstream. The DNA and ligand binding exons are identical in size and location of their boundaries to those of the human TR beta 1 gene. To determine whether the region 5' of the TR beta 2 amino terminus represented the promoter region, we examined it for sites of transcriptional initiation and for its ability to function as a promoter in TR beta 2-expressing thyrotrope cells. Multiple transcriptional start sites extending over 400 base pairs (bp) were identified with those more proximal showing inhibition by T3. Transcription was not detected more than 400 bp upstream from the putative AUG codon, although initiation downstream of this AUG was demonstrated indicating alternative AUG usage. A fragment containing 500 bp of the TR beta 2 5'-region exhibited preferential promoter activity when transfected into thyrotrope cells that express endogenous TR beta 2. Deletion studies demonstrated that removal of consensus binding sites for the transcription factor Pit-1 resulted in loss of this cell specificity. We therefore conclude that the promoter region responsible for expression of the TR beta 2 isoform in pituitary thyrotropes is distinct from that described for TR beta 1 and is located many kilobases upstream from their common exons.


Subject(s)
Receptors, Thyroid Hormone/genetics , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , Cloning, Molecular , DNA/chemistry , DNA-Binding Proteins/metabolism , Exons , Humans , Male , Mice , Mice, Inbred DBA , Molecular Sequence Data , Pituitary Gland/chemistry , Polymerase Chain Reaction , Promoter Regions, Genetic , Receptors, Thyroid Hormone/chemistry , Ribonucleases/metabolism , Transcription Factor Pit-1 , Transcription Factors/metabolism , Transcription, Genetic
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