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1.
Eur J Health Econ ; 17(2): 117-27, 2016 Mar.
Article in English | MEDLINE | ID: mdl-25479937

ABSTRACT

Including societal preferences in allocation decisions is an important challenge for the health care sector. Here, we present results of a phased discrete choice experiment investigating the impact of various attributes on respondents' preferences for distribution of health and health care. In addition to the renowned equity principles severity of illness (operationalized as initial health) and fair innings (operationalized as age), some characteristics of beneficiaries (culpability and having dependents) and the disease (rarity) were included in the choice experiment. We used a nested logit model to analyse the data. We found that all selected attributes significantly influenced respondents' choices. The phased inclusion showed that additional attributes affected respondents' preferences for previously-included attributes and reduced unobserved variance. Although not all these attributes may be considered relevant for decision making from a normative perspective, including them in choice experiments contributes to our understanding of societal preferences for each single attribute.


Subject(s)
Quality-Adjusted Life Years , Adult , Aged , Choice Behavior , Female , Humans , Male , Middle Aged , Models, Theoretical , Patient Preference , Quality of Life , Resource Allocation/methods , Surveys and Questionnaires
2.
Br J Cancer ; 108(3): 533-41, 2013 Feb 19.
Article in English | MEDLINE | ID: mdl-23361056

ABSTRACT

BACKGROUND: Screening for prostate cancer (PC) may save lives, but overdiagnosis and overtreatment are serious drawbacks. We aimed to determine men's preferences for PC screening, and to elicit the trade-offs they make. METHODS: A discrete choice experiment (DCE) was conducted among a population-based random sample of 1000 elderly men (55-75-years-old). Trade-offs were quantified with a panel latent class model between five PC screening aspects: risk reduction of PC-related death, screening interval, risk of unnecessary biopsies, risk of unnecessary treatments, and out-of-pocket costs. RESULTS: The response rate was 46% (459/1000). Men were willing to trade-off 2.0% (CI: 1.6%-2.4%) or 1.8% (CI: 1.3%-2.3%) risk reduction of PC-related death to decrease their risk of unnecessary treatment or biopsy with 10%, respectively. They were willing to pay €188 per year (CI: €141-€258) to reduce their relative risk of PC-related death with 10%. Preference heterogeneity was substantial, with men with higher educational levels having a lower probability to opt for PC screening than men with lower educational levels. CONCLUSION: Men were willing to trade-off some risk reduction of PC-related death to be relieved of the burden of biopsies or unnecessary treatments. Increasing knowledge on overdiagnosis and overtreatment, especially for men with lower educational levels, is warranted to prevent unrealistic expectations from PC screening.


Subject(s)
Choice Behavior , Early Detection of Cancer , Prostatic Neoplasms/prevention & control , Risk Reduction Behavior , Aged , Follow-Up Studies , Humans , Male , Middle Aged , Models, Statistical , Prognosis , Prostate-Specific Antigen/blood , Prostatic Neoplasms/diagnosis , Risk Factors
3.
Horm Metab Res ; 43(8): 587-90, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21667427

ABSTRACT

Cortisol increases have been associated with psychological and physiological stress; however, cortisol dynamics after weight loss (bariatric) surgery have not been defined. Obese participants not using exogenous glucocorticoids were eligible to participate. Female participants (n=24) provided salivary cortisol samples at bedtime, upon awakening the following morning, and 30 min after awakening before, and at 6 or 12 months after bariatric surgery. The Medical Outcomes Study Short Form-12 version 2 questionnaire regarding health-related quality of life was also completed. Preoperatively, mean body mass index was 45.1±8.1 kg/m2. Mean late night (1.8±1.1 nmol/l), awakening (10.7±7.4 nmol/l), and after-awakening (11.5±7.9 nmol/l) salivary cortisol values were within normal ranges. The cortisol awakening response (mean 21.1±79.7%, median 13.7%) was at the low end of normal. Preoperatively, participants had lower mental and physical health-related quality of life scores than US adult norms (p<0.001). Salivary cortisol was not correlated with measures of health-related quality of life. Mean BMI decreased over time (p<0.001) and participants experienced improved physical and mental health-related quality of life (p≤0.011). Postoperative late night salivary cortisol was not different from preoperative values. Awakening and after-awakening cortisol levels were higher than preoperative values (15.3±7.7 nmol/l, p=0.013; 17.5±10.2 nmol/l, p=0.005; respectively), but the cortisol awakening response was not changed (mean 26.7±66.2%; median 7.8%). Morning salivary cortisol increased at long-term follow-up after bariatric surgery. Although self-evaluated mental and physical health improved after surgery, the cortisol awakening response is at the low end of normal, which may indicate continued physiological stress.


Subject(s)
Bariatric Surgery , Hydrocortisone/metabolism , Saliva/metabolism , Female , Humans , Middle Aged , Postoperative Care , Preoperative Care
4.
Parasitology ; 135(11): 1281-93, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18664307

ABSTRACT

The limpet Lepetodrilus fucensis McLean is very abundant at hydrothermal vents on the Juan de Fuca and Explorer Ridges in the northeast Pacific Ocean. This limpet is parasitized by an undescribed chitonophilid copepod throughout the limpet's range. The parasite copepodite enters the mantle cavity and attaches to the afferent branchial vein. The initial invasive stage is a vermiform endosome within the vein that develops an extensive rootlet system causing an enlargement of the afferent branchial vein. Subsequently, an ectosomal female body grows outside the vein to sizes up to 2 mm in width. Once a dwarf male attaches, egg clusters form and nauplii are released. In over 3000 limpets examined from 30 populations, prevalence averaged about 5% with localized infections in female limpets over 25%. After the establishment of limpet populations at new vents, copepod prevalence increased over the succeeding months to 3 years. Host effects were marked and included castration of both sexes and deterioration in gill condition which affected both food acquisition and the gill symbiont. There was a significantly greater parasite prevalence in larger females which likely modifies the reproductive and competitive success of local host populations.


Subject(s)
Copepoda/physiology , Gastropoda/parasitology , Host-Parasite Interactions , Animals , Castration , Copepoda/ultrastructure , Female , Gastropoda/anatomy & histology , Male , Marine Biology , Microscopy, Electron, Scanning , Pacific Ocean , Prevalence , Sex Distribution
5.
J Foot Ankle Surg ; 39(4): 208-17, 2000.
Article in English | MEDLINE | ID: mdl-10949799

ABSTRACT

This retrospective study analyzes satisfaction of patients who had undergone an isolated endoscopic plantar fasciotomy (EPF) between January 1994 and January 1997. A subjective survey was completed and returned by 53 patients (a total of 69 feet), and a chart review was performed to determine final outcome. Postoperative follow-up averaged 7.2 months (range, 4-42 months). Postoperative pain levels were scored on a 7-point scale at 1 week, 1 month, and 6 months. Forty-three patients (81.1%) were satisfied with the EPF procedure and 10 patients (18.9%) were unsatisfied.


Subject(s)
Endoscopy/methods , Fasciitis/surgery , Fasciotomy , Foot Diseases/surgery , Heel , Adolescent , Adult , Aged , Fascia/physiopathology , Fasciitis/physiopathology , Female , Follow-Up Studies , Foot Diseases/complications , Foot Diseases/diagnosis , Humans , Male , Middle Aged , Pain/etiology , Pain Measurement , Patient Satisfaction , Retrospective Studies , Treatment Outcome
6.
J Foot Ankle Surg ; 39(3): 161-7, 2000.
Article in English | MEDLINE | ID: mdl-10862387

ABSTRACT

This is a retrospective study of 27 patients (35 feet) with hallux abducto valgus associated with hallux limitus who underwent a sliding oblique osteotomy for surgical treatment between August 1997 and June 1998. Radiographic analysis and range-of-motion measurements were evaluated with an average follow-up of 65 days (range, 26-100). Preoperative criteria included < 45 degrees of dorsiflexion of the first metatarsophalangeal joint with weightbearing, no evidence of degenerative joint disease at the first metatarsocuneiform joint, and no previous surgical procedures on the first ray. The average preoperative intermetatarsal angle was 9 degrees, hallux abductus angle 17 degrees, and first metatarsal declination angle 15 degrees. The average postoperative intermetatarsal angle was 6.6 degrees, hallux abductus angle 10.3 degrees, and first metatarsal declination angle 21.7 degrees. Eighteen patients (22 feet) had a follow-up of over 6 weeks, and the first metatarsophalangeal joint was evaluated. The average gain in postoperative range of motion with weightbearing was 22.3 degrees.


Subject(s)
Hallux Limitus/complications , Hallux Valgus/surgery , Metatarsal Bones/surgery , Osteotomy/methods , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Hallux Limitus/physiopathology , Hallux Valgus/complications , Hallux Valgus/physiopathology , Humans , Male , Metatarsophalangeal Joint/physiopathology , Middle Aged , Osteotomy/adverse effects , Range of Motion, Articular , Retrospective Studies
7.
Drug Alcohol Depend ; 54(3): 251-8, 1999 May 03.
Article in English | MEDLINE | ID: mdl-10372798

ABSTRACT

Although the majority of adolescents in the 13-18 age range are at school, there is a need to target specific groups of young smokers such as unemployed youth. For those young people who are not at school, few directed programs are available in either prevention or cessation and information is needed about the design and delivery of appropriate programs for this population. This report presents the results from a survey of unemployed youth and students at vocational colleges about various aspects of smoking cessation. The majority of out-of-school youth smokers had not tried to quit, but 52% were contemplating action to quit. Only a quarter of the smokers had quit for more than a week. Few young smokers would use a recognised program though more females would change to a lower nicotine brand, quit with the help of a friend or participate in a group quit program. The method of quitting most would recommend to peers is 'use of will power'. Incentives to quit were attractive to only a third of the smokers, and many enhancing and inhibiting factors for participation in programs were identified. In particular, efforts to quit increased their confidence in quitting, supporting the need to assist those who are contemplating action to quit. Programs need to incorporate input from youth and be tailored for them but not necessarily for different groups such as non-secondary school students and unemployed youth.


Subject(s)
Smoking Cessation/psychology , Smoking/psychology , Adolescent , Adult , Female , Humans , Male , Pilot Projects , Smoking/trends , Smoking Cessation/methods , Unemployment , Vocational Education
8.
J Cardiovasc Pharmacol ; 33(1): 30-5, 1999 Jan.
Article in English | MEDLINE | ID: mdl-9890393

ABSTRACT

The endothelial lining of the blood-brain barrier tightly controls the distribution of peptide hormones between the central nervous system and the circulation. By using primary cultures of brain microvessel endothelial cells, an in vitro model of the blood-brain barrier, we report here the uptake and transport of the octapeptide angiotensin II by a specific receptor population. With the angiotensin II antagonists losartan (AT1 specific) and PD 123,319 (AT2 specific), we showed that both the uptake and transport of angiotensin II were mediated by the AT1 receptor. Western blot analysis confirmed the existence of the AT1 receptor in our cell-culture model. Rhodamine 123 studies also suggested that both angiotensin II antagonists, but not angiotensin II, were substrates for the P-glycoprotein efflux system, thus restricting the transport of these compounds. These results suggest an AT1 receptor mediates uptake and transport of angiotensin II at the blood-brain barrier and may contribute to the regulation of cerebrovascular levels of the peptide.


Subject(s)
Angiotensin II/metabolism , Endothelium, Vascular/drug effects , Receptors, Angiotensin/metabolism , Angiotensin II/antagonists & inhibitors , Angiotensin II Type 1 Receptor Blockers , Angiotensin II Type 2 Receptor Blockers , Angiotensin Receptor Antagonists , Animals , Biological Transport/drug effects , Blood-Brain Barrier , Brain/blood supply , Brain/drug effects , Brain/metabolism , Capillaries/drug effects , Capillaries/metabolism , Cattle , Cell Membrane Permeability/drug effects , Cells, Cultured , Endothelium, Vascular/metabolism , Imidazoles/pharmacology , Losartan/pharmacology , Pyridines/pharmacology , Receptor, Angiotensin, Type 1 , Receptor, Angiotensin, Type 2
9.
Peptides ; 19(6): 1023-30, 1998.
Article in English | MEDLINE | ID: mdl-9700750

ABSTRACT

Angiotensin II (Ang II) uptake and transport across monolayers of bovine brain microvessel endothelial cells (BMECs) was demonstrated. Ang II transport was linear up to 2 h, saturable with a K(m) of 1.7 nM, and tended to be polarized with the apical-to-basolateral transport being greater. [3H]Ang II transport was found to be inhibited by excess unlabeled Ang II, by the Ang II analog sarathrin, and by the endocytic inhibitor phenylarsine oxide. Ang II-(2-8) and-(3-8) were shown to significantly increase the transport of Ang II. These results demonstrate for the first time the receptor-mediated transcytosis of Ang II across brain microvessel endothelium.


Subject(s)
Cerebrovascular Circulation , Endothelium, Vascular/metabolism , Receptors, Angiotensin/metabolism , Angiotensin II/metabolism , Animals , Arsenicals/pharmacology , Biological Transport, Active , Blood-Brain Barrier , Cattle , Cell Membrane Permeability , Cells, Cultured , Enzyme Inhibitors/pharmacology , Microcirculation , Monensin/metabolism
10.
Neurochem Res ; 23(2): 203-9, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9475515

ABSTRACT

The P-glycoprotein efflux system located on the apical membrane of brain capillary endothelial cells functions as part of the blood-brain barrier. In this study, primary cultures of bovine brain microvessel endothelial cells (BMECs) were investigated for the presence of a P-glycoprotein system and its contribution in regulating ivermectin distribution across the blood-brain barrier. Results of rhodamine 123 uptake studies with cyclosporin A and verapamil as substrates indicated that a functional efflux system was present on BMECs. Immunoblot analysis with the C219 monoclonal antibody to the product of the multidrug resistant member 1(MDR1) gene also confirmed the expression of MDR1 in the BMECs. Unbound ivermectin was shown to significantly increase the uptake of rhodamine 123 in BMECs, however, the drug only modestly enhanced the transcellular passage of rhodamine. The results of these studies affirmed that unbound ivermectin is an inhibitor of the MDR1 efflux system in BMECs.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology , Brain/blood supply , Brain/metabolism , Endothelium, Vascular/metabolism , Ivermectin/metabolism , Animals , Brain/cytology , Cattle , Cell Membrane Permeability/drug effects , Cells, Cultured , Endothelium, Vascular/cytology , Fluorescent Dyes/metabolism , Immunoblotting , Ivermectin/pharmacology , Microcirculation/cytology , Microcirculation/metabolism , Rhodamine 123 , Rhodamines/metabolism
11.
J Med Chem ; 40(15): 2430-3, 1997 Jul 18.
Article in English | MEDLINE | ID: mdl-9240358

ABSTRACT

Modification of the non-nucleoside inhibitor of HIV-1 reverse transcriptase nevirapine (Viramune) by incorporation of a 2-indolyl substituent confers activity against several mutant forms of the enzyme.


Subject(s)
HIV Reverse Transcriptase/antagonists & inhibitors , Pyridines/pharmacology , Reverse Transcriptase Inhibitors/pharmacology , Anti-HIV Agents/chemistry , Anti-HIV Agents/pharmacology , Cell Line , Humans , Magnetic Resonance Spectroscopy , Nevirapine , Pyridines/chemistry , Reverse Transcriptase Inhibitors/chemistry
12.
Am J Orthod Dentofacial Orthop ; 105(5): 489-95, 1994 May.
Article in English | MEDLINE | ID: mdl-8166099

ABSTRACT

Mandibular symmetry was compared between a group of 28 subjects exhibiting Class II subdivision malocclusions and 30 subjects with Class I malocclusions who served as the control group. With submentovertex radiographs, symmetry was assessed by measuring the relative difference in spatial position of mandibular landmarks in both anteroposterior and transverse dimensions as determined by coordinate systems representing the cranial floor, mandible, and mandibular dentition. Only those variables representing the anteroposterior difference between right and left mandibular molar positions showed a statistically significant difference between the groups. Whether the position of the mandibular molars was measured relative to the cranial floor or within the mandible itself, the mandibular first molar was located more posteriorly on the Class II side of the subdivision malocclusion within a mandible that exhibited no other unusual asymmetry.


Subject(s)
Facial Asymmetry/pathology , Malocclusion, Angle Class II/pathology , Mandible/pathology , Adult , Dental Arch/diagnostic imaging , Dental Arch/growth & development , Dental Arch/pathology , Dentition , Discriminant Analysis , Facial Asymmetry/complications , Female , Humans , Male , Malocclusion, Angle Class II/complications , Mandible/diagnostic imaging , Mandible/growth & development , Molar , Radiography
13.
J Gerontol ; 48(5): S245-54, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8366273

ABSTRACT

This study assessed the relationships between six different types of social support and five measures of caregiving burden. Two questions were addressed: Are all types of social support equally associated with burden, and do the same types of support correlate with different types of burden? Family caregivers (N = 217) to frail elders composed the sample. Multiple regression analyses demonstrated that all types of social support for caregivers of frail elders are not equal. Engaging in social interaction for fun and recreation appears to be the most important in diminishing the burden of caregiving. These findings are instructive both theoretically and clinically. The theoretical import of greater social participation under a condition of chronic stress is discussed. Further, interventions that focus on caregivers regularly experiencing pleasant activity with friends and other family would seem to go a long way toward managing the burden of caregiving.


Subject(s)
Caregivers/psychology , Frail Elderly , Home Nursing/psychology , Social Support , Aged , California , Caregivers/statistics & numerical data , Cost of Illness , Female , Humans , Male , Regression Analysis
14.
J Biol Chem ; 268(22): 16571-7, 1993 Aug 05.
Article in English | MEDLINE | ID: mdl-7688367

ABSTRACT

Nevirapine is a highly potent and specific inhibitor of human immunodeficiency virus type 1 (HIV-1) polymerase, but is inactive against HIV-2 and other polymerase. Previous studies demonstrated that residues 176-190 of HIV-1 reverse transcriptase (RT) can confer nevirapine sensitivity to HIV-2 RT. To better characterize the role of this sequence in HIV-1 RT, we have progressively substituted residues 176-190 of HIV-2 RT for those of HIV-1 RT and monitored the impact on the kinetic properties; inhibitory activity of nevirapine (11-cyclopropyl-5,11-dihydro-4-methyl-6H-dipyrido[2,3-b:2',3'-e] [1,4]diazepin-6-one), E-BPU (5-ethyl-1-benzyloxymethyl-6-(phenylthio)-uracil), and TIBO-R82150 ((+)-S-4,5,6,7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)imidazo[4,5,1-j k] [1,4]benzodiazepin-2(1H)-thione); and inhibitor-induced fluorescence changes of the mutant enzymes. The study revealed that in addition to Try-181 and Tyr-188, a new amino acid residue (Gly-190) plays an important role in determining susceptibility to nevirapine and E-BPU, but not to TIBO-R82150. These data argue that these non-nucleoside inhibitors fit differently, even though they share a common binding pocket. Nevirapine was seen to exert inhibitory activity by altering the interaction of the enzyme with the template-primer. Kinetic parameters were modulated by the template (DNA versus RNA) as well as by some of the mutations.


Subject(s)
Antiviral Agents/pharmacology , HIV-1/enzymology , HIV-2/enzymology , Pyridines/pharmacology , RNA-Directed DNA Polymerase/chemistry , Amino Acid Sequence , Chromatography, High Pressure Liquid , HIV Reverse Transcriptase , Kinetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Nevirapine , Reverse Transcriptase Inhibitors , Spectrometry, Fluorescence
15.
NeuroRehabilitation ; 3(1): 26-33, 1993.
Article in English | MEDLINE | ID: mdl-24525968

ABSTRACT

Vision loss increases dramatically with age but relatively little attention has been paid to blind and low-vision rehabilitation with older adults in the health care literature. The present article describes the nature and etiology of vision loss in older adults and provides an overview of the techniques and technologies available to help older adults overcome the disabilities associated with loss of vision.

16.
Protein Expr Purif ; 3(6): 479-87, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1283095

ABSTRACT

A procedure for producing and purifying recombinant HIV-1 and HIV-2 reverse transcriptase (RT) is described. These enzymes are produced by Escherichia coli-transformed with a plasmid containing the gene encoding for either the human immunodeficiency virus type 1 (HIV-1) or HIV-2 RT protein. Both proteins are partially processed by host cell proteases giving rise to a mixture of heterodimeric and nonheterodimeric products, which are subsequently resolved to near homogeneity by chromatography on phosphocellulose, Q-Sepharose, and hydrophobic interaction HPLC. Both HIV-1 (66/51 kDa) and HIV-2 (68/54 kDa) heterodimeric enzymes devoid of excess unprocessed (p66 or p68) precursors are isolated, enabling comparative enzymatic characterization of the fully active (and biologically relevant) heterodimeric forms. Homogenous HIV-1 and HIV-2 RT purified by this methodology exhibit near equivalent polymerase and RNase H activities.


Subject(s)
RNA-Directed DNA Polymerase/isolation & purification , Amino Acid Sequence , Base Sequence , Chromatography/methods , Cloning, Molecular , Escherichia coli/genetics , HIV Reverse Transcriptase , Molecular Sequence Data , Protein Processing, Post-Translational , RNA-Directed DNA Polymerase/genetics , RNA-Directed DNA Polymerase/metabolism , Recombinant Proteins/isolation & purification
18.
Proc Natl Acad Sci U S A ; 88(21): 9878-82, 1991 Nov 01.
Article in English | MEDLINE | ID: mdl-1719542

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT), an important therapeutic target in the treatment of AIDS, is effectively inhibited by a class of nonnucleoside analog compounds that includes nevirapine (BI-RG-587) and tetrahydroimidazo[4,5,1-jk]-[1,4]benzodiazepin-2(1H)-one and -thione. We show that both tyrosine residues at positions 181 and 188 flanking the putative catalytic site of HIV-1 RT are required for sensitivity of the enzyme to these compounds. HIV-2 RT, which does not have tyrosines at these positions, is resistant to these nonnucleoside analog inhibitors. Substitution of the HIV-2 RT amino acid residues at position 181 or 188 into HIV-1 RT results in an enzyme that is resistant to these compounds while retaining sensitivity to 3'-azido-2',3'-dideoxythymidine triphosphate. HIV-2 RT substituted with amino acids 176-190 from HIV-1 RT acquires sensitivity to these nonnucleoside analog inhibitors.


Subject(s)
Azepines/pharmacology , Benzodiazepines/pharmacology , HIV-1/enzymology , HIV-2/enzymology , Imidazoles/pharmacology , Pyridines/pharmacology , Reverse Transcriptase Inhibitors , Affinity Labels , Amino Acid Sequence , Binding Sites , DNA Mutational Analysis , Molecular Sequence Data , Nevirapine , RNA-Directed DNA Polymerase/chemistry , RNA-Directed DNA Polymerase/metabolism , Recombinant Fusion Proteins , Structure-Activity Relationship , Tyrosine/physiology
19.
Psychol Aging ; 6(2): 232-7, 1991 Jun.
Article in English | MEDLINE | ID: mdl-1863392

ABSTRACT

The relationship between social support and depression was studied in 165 women caring for frail family members. The Arizona Social Support Interview Schedule (Barrera, Sandler, & Ramsay, 1981), which includes 4 dimensions of availability and use of resources and satisfaction with and need for support, was used to examine 7 categories of supportive activity. Depression was assessed according to Research Diagnostic Criteria (Spitzer, Endicott, & Robins, 1978) with the Schedule of Affective Disorders and Schizophrenia (Endicott & Spitzer, 1978). There were no differences in overall satisfaction with received support in comparisons of depressed and nondepressed caregivers. However, depressed caregivers (n = 87) reported a higher incidence of negative interactions with others. Both groups appeared to have equal access to social support, with nondepressed caregivers (n = 78) reporting significantly greater use of those resources.


Subject(s)
Depression/psychology , Frail Elderly/psychology , Home Nursing/psychology , Respite Care/psychology , Social Support , Activities of Daily Living/psychology , Adult , Aged , Aged, 80 and over/psychology , Female , Humans , Interpersonal Relations , Middle Aged , Personal Satisfaction
20.
J Biol Chem ; 266(18): 11604-9, 1991 Jun 25.
Article in English | MEDLINE | ID: mdl-2050668

ABSTRACT

The structure of the gene encoding a chicken liver receptor, the chicken hepatic lectin, which mediates endocytosis of glycoproteins has been established. The coding sequence is divided into six exons separated by five introns. The first three exons correspond to separate functional domains of the receptor polypeptide (cytoplasmic tail, transmembrane sequence, and extracellular neck region), while the final three exons encode the Ca(2+)-dependent carbohydrate-recognition domain. These results, as well as computer-assisted multiple sequence comparisons, establish this receptor as the evolutionary homolog of the mammalian asialoglycoprotein receptors. It is interesting that the chicken receptor falls into a subfamily of proteins along with the mammalian asialoglycoprotein receptors, since the saccharide-binding specificity of the chicken receptor resembles more closely that of a different set of calcium-dependent animal lectins, which includes the mannose-binding proteins. The portions of the genes encoding the carbohydrate-recognition domains of these proteins lack introns. The results suggest that divergence of intron-containing and intron-lacking carbohydrate-recognition domains preceded shuffling events in which other functional domains were associated with the carbohydrate-recognition domains. This was followed by further divergence, generating a variety of saccharide-binding specificities.


Subject(s)
Biological Evolution , Carbohydrate Metabolism , Lectins/genetics , Multigene Family , Amino Acid Sequence , Animals , Asialoglycoprotein Receptor , Base Sequence , Cattle , Chickens , Dogs , Endocytosis , Exons , Humans , Introns , Lectins/physiology , Liver/metabolism , Molecular Sequence Data , Rats , Receptors, Immunologic/genetics , Sequence Homology, Nucleic Acid
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