RESUMEN
We explored the role of negative performance beliefs and self-focused attention considered central to psychological models of social anxiety but not studied in autism. Firstly, we compared self- and observer ratings of performance on a social task for 71 young autistic people, 41 high and 30 low in social anxiety, finding a significant main effect of social anxiety but not rater. Subsequently, 76 autistic young people, 46 high and 30 low social anxiety completed measures of interoceptive sensibility and focus of attention following a social task. Only heightened interoceptive sensibility fully mediated the relationship between self-ratings of social performance and social anxiety. These findings suggest awareness of bodily sensations are critical to anxiety in social situations with implications for treatment.
Asunto(s)
Trastorno del Espectro Autista , Trastorno Autístico , Humanos , Adolescente , Trastorno Autístico/psicología , Trastorno del Espectro Autista/psicología , Ansiedad/psicología , Atención , CogniciónRESUMEN
Intolerance of Uncertainty is a transdiagnostic risk and maintenance factor in a range of anxiety disorders and major depressive disorder. However, the mechanism of action in the development and maintenance of anxiety disorders is poorly understood, with the relationship between the constructs of uncertainty and threat appraisal remaining unclear. Most research to date has investigated IU in situations that are explicitly or implicitly threatening (i.e. where they have a negative outcome), which makes it difficult to establish whether it is the uncertainty or the prospect of a negative outcome (or threat) that people find aversive. If the construct of IU is about uncertainty (and not threat), it should also be operating in situations where there are no negative outcomes possible. Participants (Nâ¯=â¯224) completed a battery of online measures in tasks designed to evaluate level of situational uncertainty and perception of threat level. These tasks required responses to scenarios which displayed or implied varying levels of estimated threat. Regression analyses indicated that IU was related to perceiving threat and uncertainty in negative situations and positive situations, with the greatest contribution from uncertainty within the situations, supporting the conceptualisation of IU as a response to uncertainty that is largely independent of threat although may contribute to perceptions of threat.
Asunto(s)
Trastornos de Ansiedad/psicología , Ansiedad/psicología , Incertidumbre , Adolescente , Adulto , Afecto , Anciano , Trastorno Depresivo Mayor/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Regresión , Adulto JovenRESUMEN
Two-pore potassium channels can influence neuronal excitability by regulating background leakage of potassium ions and resting membrane potential. The present study used quantitative real time PCR and in situ hybridization to determine if the decreased activity from deafness would induce changes in two-pore potassium channel subunit expression in the rat inferior colliculus (IC). Ten subunits were assessed with quantitative real-time PCR at 3 days, 3 weeks and 3 months following bilateral cochlear ablation. TASK-1, TASK-5 and THIK-2 showed significant decreases in expression at all three times assessed. TASK-5, relatively specific to auditory neurons, had the greatest decrease. TWIK-1 was significantly decreased at 3 weeks and 3 months following deafness and TREK-2 was only significantly decreased at 3 days. TASK-3, TWIK-2, THIK-1, TRAAK and TREK-1 did not show any significant changes in gene expression. In situ hybridization was used to examine TASK-1, TASK-5, TWIK-1 and THIK-2 in the central nucleus, dorsal cortex and lateral (external) cortex of the IC in normal hearing animals and at 3 weeks following deafening. All four subunits showed expression in neurons throughout IC subdivisions in normal hearing rats, with TASK-5 having the greatest overall number of labeled neurons. There was no co-localization of subunit expression with glial fibrillary acidic protein immunostaining, indicating no expression in glia. Three weeks following deafening there was a significant decrease in the number of neurons expressing TASK-1 and THIK-2 in the IC, while TASK-5 had significant decreases in the central nucleus and dorsal cortex and TWIK-1 in the lateral and dorsal cortices.
Asunto(s)
Sordera/genética , Sordera/fisiopatología , Colículos Inferiores/fisiopatología , Canales de Potasio de Dominio Poro en Tándem/genética , Canales de Potasio de Dominio Poro en Tándem/fisiología , Animales , Cóclea/fisiopatología , Regulación hacia Abajo , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Hibridación in Situ , Colículos Inferiores/crecimiento & desarrollo , Masculino , Proteínas del Tejido Nervioso , Canales de Potasio de Dominio Poro en Tándem/metabolismo , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Four cases of actinomycosis involving the uterus and adnexal structures are reported. In 2 cases the infection was transmitted from a ruptured appendix. Ascending actinomycosis involving the endometrium and resulting in adnexal abscesses was associated with the use of an IUD in 2 patients. This infection should be suspected in any patient who develops a pelvic abscess with an IUD in place. Culture and histologic examination of tissue removed with the IUD may be a means of early diagnosis. The nature of these infections became apparent only after serious complications developed. Each patient required several surgical procedures. The diagnosis remained unsuspected until repeated laboratory examinations detected the fungus. The difficulty encountered identifying Actinomyces israeli indicates the infection is often undetected. Gallium scans were helpful in localizing occult abscesses in 2 patients.
PIP: 4 cases of actinomycosis, treated at the University of Virginia Hospital, involved the uterus and adnexal structures. 2 cases were the result of a transferred infection from a ruptured appendix. Ascending actinomycosis involved the endometrium and resulted in adnexal abcesses for 2 patients in which infection was associated with the use of an IUD. A means of early diagnosis might be through examination of tissue removed with an IUD. The nature of these infections becomes apparent only after serious complications develop. Patients required several surgical procedures. The diagnosis may remain undetected through repeated examination in the laboratory. This difficulty in detecting Actinomyces israeli indicates that the infection may often be undetected. Gallium scans were helpful in localizing occult abscesses i n 2 patients.
Asunto(s)
Absceso/microbiología , Actinomicosis/diagnóstico , Enfermedades de los Genitales Femeninos/microbiología , Actinomyces/aislamiento & purificación , Actinomicosis/patología , Enfermedades de los Anexos/microbiología , Adolescente , Adulto , Apendicitis/complicaciones , Femenino , Humanos , Dispositivos Intrauterinos/efectos adversos , Enfermedades del Ovario/microbiología , Cintigrafía , Enfermedades Uterinas/microbiologíaRESUMEN
A patient with a progesterone-producing granulosa cell carcinoma is the basis of this report. Seven years after initial surgical therapy pelvic masses were palpated. At laparotomy the recurrence of tumor was confirmed, and many nonresectable metastases were discovered on the surface of the liver and on the mesentery of the bowel. An exceedingly high plasma progesterone level of 6270 pg/ml was obtained in the postoperative period. During 12 months of single agent chemotherapy with melphalan, serial plasma progesterone assays declined to 310 pg/ml. Complete tumor regression was subsequently confirmed by laparoscopy. Evaluation of progesterone levels in patients with granulosa cell tumors is recommended to determine the incidence of this finding and to further assess its value in following response to therapy.
Asunto(s)
Tumor de Células de la Granulosa/sangre , Hormonas Ectópicas/sangre , Neoplasias Ováricas/sangre , Progesterona/sangre , Anciano , Femenino , Tumor de Células de la Granulosa/cirugía , Humanos , Histerectomía , Melfalán/administración & dosificación , Metástasis de la Neoplasia , Neoplasias Ováricas/cirugíaRESUMEN
The pharmacokinetics of meropenem were determined in 9 healthy volunteers after the administration of 1 g dose by injection over 2, 3 or 5 min. Peak plasma concentrations were not significantly different across the three rates of administration and, due to the finite time required for complete mixing of the blood in the central compartment, did not always occur at the end of the injection. Overall exposure to meropenem was unchanged by the more rapid rates of administration. Plasma clearance, terminal half-life and volume of distribution were virtually unchanged. Within 10 min after the start of the injection, the plasma concentrations from all three injections were very similar indicating that dosing over 2, 3 or 5 min would result in similar antimicrobial cover and, therefore, comparable efficacy. Comparison of the data derived from the three injections indicated that rapid administration of meropenem did not appreciably alter its disposition pharmacokinetics. Tolerability of meropenem was unchanged with the more rapid administration rate.
Asunto(s)
Antiinfecciosos/farmacocinética , Tienamicinas/farmacocinética , Adolescente , Adulto , Antiinfecciosos/administración & dosificación , Antiinfecciosos/sangre , Área Bajo la Curva , Humanos , Inyecciones Intravenosas , Masculino , Meropenem , Persona de Mediana Edad , Tienamicinas/administración & dosificación , Tienamicinas/sangreRESUMEN
Health care in developing countries is discussed in terms of the administrative systems, medical manpower and technologies which are most appropriate to the economic and cultural environment in which they will be used. Appropriate technology must be preceded by appropriate research and development and those involved in the training of overseas students should critically examine the relevance of the course to the needs of the students.
Asunto(s)
Ingeniería Biomédica , Países en Desarrollo , Ciencia del Laboratorio Clínico , Colorimetría , Diarrea/terapia , Fuerza Laboral en Salud , Humanos , Hielo , Inmunización , Ciencia del Laboratorio Clínico/tendencias , Atención Primaria de Salud/organización & administración , Refrigeración , Organización Mundial de la SaludAsunto(s)
Carcinoma de Ehrlich/tratamiento farmacológico , Células Clonales , Resistencia a Medicamentos , Guanosina/uso terapéutico , Microesferas , Mutágenos , Animales , Azaguanina/farmacología , Inyecciones Intravenosas , Pulmón/efectos de los fármacos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/etiología , Mercaptopurina/farmacología , Mercaptopurina/uso terapéutico , Métodos , Ratones , Ratones Endogámicos ICR , Trasplante de Neoplasias , Trasplante HomólogoAsunto(s)
Adenosina Trifosfato/metabolismo , Adenosina/metabolismo , Carcinoma de Ehrlich/metabolismo , Aminohidrolasas/metabolismo , Animales , Radioisótopos de Carbono , Desaminación , Glucosa , Técnicas In Vitro , Inosina/metabolismo , Ratones , Ratones Endogámicos ICR , Fosfotransferasas/metabolismoAsunto(s)
Adenina/análogos & derivados , Inhibidores de la Adenosina Desaminasa , Antibióticos Antineoplásicos/farmacología , Formicinas/farmacología , Nucleósido Desaminasas/antagonistas & inhibidores , Adenina/farmacología , Animales , Carcinoma de Ehrlich/enzimología , Células Cultivadas , Metabolismo Energético/efectos de los fármacos , Humanos , Inosina/metabolismo , Ratones , Nucleótidos de Purina/metabolismo , Factores de TiempoAsunto(s)
Carcinoma de Ehrlich/enzimología , Purinas/metabolismo , Amidofosforribosiltransferasa/metabolismo , Animales , Glutamina/metabolismo , Cinética , Fosforribosil Pirofosfato/biosíntesis , Nucleótidos de Purina/metabolismo , Purinas/biosíntesis , Ribonucleótidos/biosíntesis , Ribosa-Fosfato Pirofosfoquinasa/metabolismoRESUMEN
BACKGROUND: There are few theoretical proposals that attempt to account for the variation in affective processing across different affective states of bipolar disorder (BD). The Interacting Cognitive Subsystems (ICS) framework has been recently extended to account for manic states. Within the framework, positive mood state is hypothesized to tap into an implicational level of processing, which is proposed to be more extreme in states of mania. METHOD: Thirty individuals with BD and 30 individuals with no history of affective disorder were tested in euthymic mood state and then in induced positive mood state using the Question-Answer task to examine the mode of processing of schemas. The task was designed to test whether individuals would detect discrepancies within the prevailing schemas of the sentences. RESULTS: Although the present study did not support the hypothesis that the groups differ in their ability to detect discrepancies within schemas, we did find that the BD group was significantly more likely than the control group to answer questions that were consistent with the prevailing schemas, both before and after mood induction. CONCLUSIONS: These results may reflect a general cognitive bias, that individuals with BD have a tendency to operate at a more abstract level of representation. This may leave an individual prone to affective disturbance, although further research is required to replicate this finding.
Asunto(s)
Afecto , Concienciación , Trastorno Bipolar/psicología , Trastornos del Conocimiento/psicología , Pruebas Neuropsicológicas/estadística & datos numéricos , Adulto , Atención , Trastorno Bipolar/diagnóstico , Trastornos del Conocimiento/diagnóstico , Comprensión , Femenino , Humanos , Masculino , Memoria a Corto Plazo , Persona de Mediana Edad , Inventario de Personalidad/estadística & datos numéricos , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Psicometría/estadística & datos numéricos , Lectura , Reproducibilidad de los Resultados , SemánticaRESUMEN
Surfactant protein C (SP-C) is a 3.7-kDa hydrophobic peptide isolated from organic extracts of pulmonary surfactant which is secreted by alveolar type II cells after synthesis and posttranslational processing of a 21-kDa proSP-C peptide (SP-C21). Previously characterized epitope-specific proSP-C antisera were used to study early proteolytic steps of proSP-C processing by adult rat type II cells. Western blotting and immunocytochemistry using anti-NPROSP-C (epitope = Met10-Glu23) each demonstrated marked attenuation of proSP-C protein expression by culture on plastic. Processing was therefore studied by metabolic labeling of freshly isolated type II cells maintained in suspension in serum-free media. With the use of anti-NPROSP-C, immunoprecipitation of cell lysates continuously labeled for 4 h with [35S]methionine demonstrated radiolabeled bands of M(r) 21, 16, and 10-6,000 while anti-CTERMSP-C (epitope = Ser149-Ser166) failed to detect 35S-bands of M(r) < 16,000. Pulse-chase studies demonstrated synthesis of 35S-proSP-C21 with a time-dependent dependent appearance of 16-kDa and 10- to 6-kDa forms which was blocked by addition of brefeldin A. SP-C precursors were not detected in the media. Quantitative analysis of the major bands by direct beta-counting indicated a precursor-product relationship between SP-C21 and SP-C16. These results demonstrate the utility of freshly isolated type II cells for characterization of SP-C synthetic pathways and show that early proSP-C processing events include synthesis of a 21-kDa primary translation product followed by extensive intracellular proteolysis of the proSP-C COOH-terminal in subcellular compartments of type II cells which are distal to the trans-Golgi network.
Asunto(s)
Procesamiento Proteico-Postraduccional , Proteolípidos/metabolismo , Alveolos Pulmonares/metabolismo , Surfactantes Pulmonares/metabolismo , Animales , Western Blotting , Brefeldino A , Separación Celular , Células Cultivadas , Ciclopentanos/farmacología , Inmunohistoquímica , Cinética , Fragmentos de Péptidos/metabolismo , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Inhibidores de la Síntesis de la Proteína/farmacología , Alveolos Pulmonares/citología , Ratas , Ratas Sprague-DawleyRESUMEN
A mutant of yeast sensitive to growth inhibition by 2,6-diaminopurine (2,6-DAP) was analyzed genetically and found to be a double mutant. One gene, dap, conferred approximately 30% sensitivity to the analogue. The other, slw, potentiated the inhibition such that the double mutant dap slw was inhibited 90%. The mutation dap conferred concomitant sensitivity to a number of other purine analogues. The activity of a purine phosphoribosyltransferase with 2,6-DAP in a strain carrying dap was found to be three times higher than in the wild type. It is inferred that the mutation alters the properties of a purine phosphoribosyltransferase. A possible mechanism for the effect of slw is also discussed.
Asunto(s)
Purinas/farmacología , Levaduras/crecimiento & desarrollo , Adenina/farmacología , Centrifugación , Genética Microbiana , Genotipo , Hipoxantinas/farmacología , Mutación , Fenotipo , Transferasas/farmacología , Xantinas/farmacología , Levaduras/aislamiento & purificaciónRESUMEN
Six mutants, allelic to ade3, were isolated after mutagenic treatment of a prototrophic strain of yeast. All six grow on medium supplemented with adenine alone and four respond to histidine. Supplementation with adenine plus histidine or methionine inhibits growth, but a mixture of these three is stimulatory. Heteroallelic diploids formed by the new mutants with the standard ade3 can resemble either parent or show an intermediate phenotype. The new mutants, unlike standard ade3, are not fully epistatic to ade2. The activities of three enzymes concerned in tetrahydrofolate metabolism have been assayed in the new and standard ade3 mutants and wild type. The only difference detected between the new and standard ade3 was in the levels of 10-formyltetrahydrofolate synthetase. Activity in the new mutants ranged from 36 to 109% of wild type compared with 10 to 12% in the standard ade3. Possible mechanisms to account for the varied phenotypes at the ade3 locus are discussed.
Asunto(s)
Adenina/metabolismo , Genética Microbiana , Mutación , Saccharomyces/metabolismo , Alelos , Aminohidrolasas/metabolismo , Sistema Libre de Células , Mapeo Cromosómico , Cruzamientos Genéticos , Medios de Cultivo , Diploidia , Ácido Fólico/metabolismo , Prueba de Complementación Genética , Histidina/metabolismo , Indicadores y Reactivos , Ligasas/metabolismo , Metionina/metabolismo , Mutágenos , Oxidorreductasas/metabolismo , Pigmentos Biológicos/biosíntesis , Recombinación Genética , Saccharomyces/enzimología , Saccharomyces/crecimiento & desarrollo , Saccharomyces/aislamiento & purificación , Espectrofotometría , Ácidos SulfónicosRESUMEN
Ehrlich ascites tumor cells containing radioactive ATP were incubated in vitro with a range of concentrations of 2-deoxyglucose in order to produce different rates of ATP catabolism. Concentrations of all radioactive products of ATP catabolism were measured, and apparent rates of adenylate deaminase and inosinate dehydrogenase and of adenylate and inosinate dephosphorylation were calculated. It was concluded that these processes were reggulated primarily by the rate of formation of substrate, and to a lesser extent in some cases, by substrate concentration. No evidence was obtained for regulation of these processes by the concentration of ATP. The deoxyglucose-induced catabolism of radioactive GTP was also studied. When ATP catabolism was induced by incubation with 2,4-dinitrophenol, time courses of accumulation of purine nucleoside monophosphates and rates of alternative pathways of their metabolism were quite different than when deoxyglucose was used.
Asunto(s)
Adenosina Trifosfato/metabolismo , Guanosina Trifosfato/metabolismo , Adenosina , Adenosina Monofosfato/metabolismo , Aminohidrolasas/metabolismo , Animales , Antimetabolitos/farmacología , Carcinoma de Ehrlich/metabolismo , Desoxiglucosa/farmacología , Nucleótidos de Inosina/metabolismo , Cinética , Ratones , Fosfotransferasas/metabolismo , Factores de TiempoRESUMEN
Conditions necessary for the establishment and maintenance of transformation of human cells by wild type and temperature-sensitive mutants of SV40 were examined. For both early and late mutants, the frequency of transformation was found to be up to 5-fold higher, and virus yield 100-fold lower, at 39 degrees than at 33 degrees. No such effect was observed with the wild type virus under the same conditions. This observation is apparently at variance with previously published work, but may be explained by the semipermissive nature of the cells that we used. Increasing the temperature to 40.5 degrees caused cells transformed by the early mutant, tsA30, to lose T-antigen as detectable by staining, and also to lose the ability to grow to high density, while it produced no effect on cells transformed by wild type virus.
Asunto(s)
Transformación Celular Neoplásica , Transformación Celular Viral , Virus 40 de los Simios/crecimiento & desarrollo , Antígenos de Neoplasias , Antígenos Virales , Recuento de Células , División Celular , Células Cultivadas , Genes Virales , Mutación , TemperaturaRESUMEN
Cultures of human cells transformed by SV40 were found to release infectious virus, even after several passages in vitro. Virus shedding by these cultures did not depend on propagation of virus from cell to cell, as it was not affected by anti-SV40 antiserum that could effectively block virus propagation in acutely infected cells. Cells transformed by the 'early' temperature-sensitive mutant tsA30, and maintained at the restrictive temperature of 39 degrees, shed virus in reduced amount. Finally, xeroderma pigmentosum cells transformed by SV40 were also found to release virus, indicating that the enzymes of excision and repair of UV-induced damage to DNA probably were not involved in the molecular mechanism underlying virus shedding.
Asunto(s)
Transformación Celular Viral , Virus 40 de los Simios/crecimiento & desarrollo , Anticuerpos Antivirales , Línea Celular , Efecto Citopatogénico Viral , Virus 40 de los Simios/inmunología , Temperatura , Ensayo de Placa Viral , Xerodermia PigmentosaRESUMEN
Surfactant protein C (SP-C) is synthesized by alveolar type II cells as a 21-kDa propeptide (proSP-C21) which is proteolytically processed in subcellular compartments distal to the trans-Golgi network to yield a 35-residue mature form. Initial synthetic processing events for SP-C include post-translational cleavages of the COOH terminus of proSP-C21 yielding two intermediates (16 and 6 kDa). To test the role of specific COOH-terminal domains in intracellular targeting and proteolysis of proSP-C21, synthesis and processing of SP-C was evaluated using a lung epithelial cell line (A549) transfected with a eukaryotic expression vector containing either the full-length cDNA for rat SP-C (SP-Cwt) or one of six polymerase chain reaction (PCR)-generated COOH terminally truncated forms (SP-C1-185, SP-C1-175, SP-C1-147, SP-C1-120, SP-C1-72, and SP-C1-59). Using in vitro transcription/translation, each of the seven constructs produced a 35S-labeled product of appropriate length which could be immunoprecipitated by epitope specific proSP-C antisera. Immunoprecipitation of 35S-labeled A549 cell lysates from SP-Cwt transfectants demonstrated rapid synthesis of [35S]proSP-C21 with processing to SP-C16 and SP-C6 intermediates via cleavages of the COOH-terminal propeptide. Both the intermediates as well as the kinetics of processing in A549 cells were similar to that observed in rat type II cells. In contrast, constructs SP-C1-185, SP-C1-175, SP-C1-147, SP-C1-120, SP-C1-72, and SP-C1-59 were each translated but degraded without evidence of proteolytic processing. Fluorescence immunocytochemistry identified proSP-Cwt in cytoplasmic vesicles of A549 cells while all COOH-terminal deletional mutants were restricted to an endoplasmic reticulum/Golgi compartment identified by co-localization with fluorescein isothiocyanate-concanavalin A. We conclude that SP-Cwt expressed in A549 cells is directed to cytoplasmic vesicles where it is proteolytically processed in a manner similar to native type II cells and that amino acids Cys186-Ile194 located at the COOH terminus of proSP-C21 are necessary for correct intracellular targeting and subsequent cleavage events.
Asunto(s)
Procesamiento Proteico-Postraduccional/fisiología , Proteolípidos/fisiología , Alveolos Pulmonares/metabolismo , Surfactantes Pulmonares/fisiología , Animales , Regulación de la Expresión Génica/genética , Aparato de Golgi/fisiología , Humanos , Inmunohistoquímica , Mutagénesis/genética , Reacción en Cadena de la Polimerasa , Ratas , Homología de Secuencia de Aminoácido , Transfección/genética , Células Tumorales CultivadasRESUMEN
Rat surfactant protein (SP) C is synthesized as a 194-amino acid proprotein that is proteolytically processed to a 35-amino acid mature form in subcellular compartments distal to the medial Golgi compartment. To identify domains of SP-C proprotein (proSP-C) necessary for endoplasmic reticulum translocation and for targeting to cytosolic processing compartments, we characterized expression patterns of heterologous SP-C fusion proteins in A549 lung epithelial cells and in the rat pheochromocytoma cell line PC-12. cDNA constructs were produced; these constructs encoded fusion proteins consisting of enhanced green fluorescent protein (EGFP) and wild-type proSP-C (EGFP/SP-C(1-194)), mature SP-C (EGFP/SP-C(24-59)), or progressive deletions of the NH(2)- or COOH-terminal flanking domains. By fluorescence microscopy, EGFP/SP-C(1-194) transfected into A549 cells was translocated and expressed in acidic cytoplasmic vesicles. By deletional analysis, a functional signal peptide was mapped to the domain Phe(24) to His(59), whereas a motif for targeting to cytosolic vesicular compartments was localized to the NH(2) flanking domain Met(10) to Gln(23). Truncations of the distal COOH terminus were retained in the endoplasmic reticulum/Golgi compartment; however, the COOH flanking region alone was insufficient for targeting. In PC-12 cells, EGFP/SP-C(1-194) was expressed in peripheral cytosolic vesicles, whereas EGFP/SP-C(24-194) and EGFP/SP-C(24-59) were each translocated but not targeted. We conclude that two domains in the proSP-C sequence are required for targeting: mature SP-C (Phe(24) to Leu(58)) contains a functional signal sequence active in epithelial and nonepithelial cells, whereas Met(10) to Gln(23), but not the COOH flanking peptide, is required for targeting to late vesicular compartments.