RESUMEN
The tailings dump of Barraxiutta (Sardinia, Italy) contains considerable concentrations of heavy metals and, consequently, is scarcely colonized by plants. However, wild populations of the liverwort Lunularia cruciata (L.) Dum. form dense and healthy-looking carpets on this tailing dump. L. cruciata colonizing the tailing dump was compared with a control population growing in a pristine environment in terms of: (i) pollutant content, (ii) photochemical efficiency, and (iii) volatile secondary metabolites in thalli extracts. L. cruciata maintained optimal photosynthesis despite containing considerable amounts of soil pollutants in its thalli and had higher sesquiterpene content compared to control plants. Sesquiterpenes have a role in plant stress resistance and adaptation to adverse environments. In the present study, we propose enhanced sesquiterpenes featuring Contaminated L. cruciata as a defence strategy implemented in the post-mining environment.
RESUMEN
The lock and key hypothesis assumes that male and female genitalia match in a unique system to prevent interspecific crosses. This hypothesis is largely investigated in animals, while there is a distinct lack of studies on plants. Nevertheless, we expect the lock and key hypothesis could apply to plants with complex floral morphologies, such as orchids. Here we apply a comparative approach to examine the variation of floral functional traits in food- and sex-deceptive orchids. To understand if a specific deception strategy is related to a specific variation in floral traits evaluated the variation in sterile and fertile traits among species and subsequently examined the correlations between male and female reproductive organs of the same species with the aim of investigating the role of the lock and key hypothesis in deceptive orchids. Our results show that the functional morphology of fertile traits plays a pivotal role in limiting gene flow in species that grow in sympatry. In particular, it was observed that the Reproductive Standardisation Index (RSI) is significantly different in the two pollination strategies and that the correlation between pollinarium length and stigmatic cavity length is stronger in food-deceptive species when compared to the sex-deceptive species. These results reveal that the lock and key hypothesis contributes to maintain boundaries in plants with very complex floral morphology.
Asunto(s)
Flores/anatomía & histología , Orchidaceae/anatomía & histología , Polinización , Flores/fisiología , Flujo Génico , Orchidaceae/fisiología , Polinización/fisiología , SimpatríaRESUMEN
AIM: Treatment of toxic nodular goiter with ¹³¹I is a first-line therapy for hyperthyroidism. To avoid a thyrotoxic storm, ¹³¹I is usually administered after pretreatment with antithyroid drugs, with thyroid-stimulating hormone (TSH) increase and functional recruitment of inhibited normal tissue. Therefore, both autonomous nodule(s) and normal tissue are irradiated. This may be a reason for late hypothyroidism occurring in 15-25% of patients. This study aimed at assessing different pretreatment modalities with combined methymazole and triiodothyronine, achieving euthyroidism with suppressed TSH. METHODS: After diagnosis of autonomously functioning toxic nodule, patients were subjected to thyrostatic medication. Two months later, TSH was checked; if >0.5 mU/L triiodothyronine treatment was associated. After 2 more months, if the TSH level was suppressed, patients received ¹³¹I-therapy. A total of 149 patients were consecutively enrolled, 41 of whom with uninodular and 108 with multinodular goiter. They were evaluated at diagnosis, pretreatment, 3 and 6 months after therapy and at late follow-up (6.8+/-4.2 years; range: 1-22 years). RESULTS: Administered activity was calculated according to ¹³¹I uptake and gland weight. Methymazole was discontinued 6 days before treatment and T3 was maintained until administration of ¹³¹I-therapy. Euthyroidism was achieved in 88% of patients. At late follow-up, subclinical hypothyroidism was observed in 10 patients (6.7%) and overt hypothyroidism in 5 patients (3.3%). No pathological consequences or side effects of ¹³¹I-therapy were found during the 6.8+/-4.2 year follow-up period. CONCLUSION: Treatment of toxic nodular goiter with ¹³¹I-therapy, under combined thyrostatic-thyromimetic treatment is a simple, safe, well-tolerated, and effective procedure.
Asunto(s)
Bocio Nodular/tratamiento farmacológico , Bocio Nodular/radioterapia , Tirotoxicosis/tratamiento farmacológico , Tirotoxicosis/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Antitiroideos/uso terapéutico , Terapia Combinada , Femenino , Humanos , Hipotiroidismo/prevención & control , Radioisótopos de Yodo/uso terapéutico , Masculino , Metimazol/uso terapéutico , Persona de Mediana Edad , Factores de Tiempo , Triyodotironina/uso terapéuticoRESUMEN
PURPOSE: We have carried out experiments to determine if human cervical mucus can act as an in vitro selective barrier against spermatozoa morphologically normal that carry genetic structural abnormalities. METHODS: Sperm chromatin abnormalities have been evaluated by Chromomycin A3 and "endogenous" nick translation. RESULTS: The data obtained have shown that spermatozoa possessing higher levels of DNA protamination are more proficient in crossing the cervical mucus barrier. Moreover, the levels of positivity to endogenous nick translation treatment was practically zero in such spermatozoa. CONCLUSIONS: We suggest that sperm penetration of cervical mucus could be used to select sperm preparations free of fragmented DNA or chromatin structural abnormalities for assisted reproduction.
Asunto(s)
Moco del Cuello Uterino/fisiología , Cromatina/fisiología , ADN/fisiología , Espermatozoides/fisiología , Cromomicina A3/farmacología , Femenino , Colorantes Fluorescentes , Humanos , Masculino , Microscopía Fluorescente , Distribución Aleatoria , Espermatozoides/anomalíasRESUMEN
BACKGROUND/AIM: In idiopathic nephrotic syndrome (INS), ciclosporin A (CsA) was shown to decrease proteinuria, an effect explained by its immunologic and hemodynamic actions. In order to determine whether CsA could have a direct action on glomerular cells, we studied the effect of CsA on glomerular cells in vitro, particularly on glycosaminoglcycans (GAG) and heparan sulfates (HS) which are decreased in INS patients. METHODS: Human glomerular epithelial cells and rat mesangial cells were cultured at various concentrations of CsA. HS were quantified using a cationic membrane after metabolic labeling. RESULTS: Mesangial cell GAG and HS and epithelial cell HS increased significantly when cells were cultured with CsA. For both cell types this increase was prevailing on the secreted fraction of HS in comparison with the cellular fraction. CsA induced also an increase in cellular cAMP levels, but the effect of CsA was not transduced via a cAMP pathway. CONCLUSIONS: CsA is able to increase glomerular GAG and HS in vitro. As this effect of CsA was the opposite effect on glomerular cells to the effect of plasma from INS patients, we conclude that this direct action of CsA on glomerular cells could explain in part the effect of this drug in decreasing proteinuria in INS.
Asunto(s)
Ciclosporina/farmacología , Heparitina Sulfato/metabolismo , Inmunosupresores/farmacología , Glomérulos Renales/metabolismo , Síndrome Nefrótico/tratamiento farmacológico , Animales , Células Cultivadas , AMP Cíclico/metabolismo , Mesangio Glomerular/citología , Mesangio Glomerular/efectos de los fármacos , Mesangio Glomerular/metabolismo , Glicosaminoglicanos/metabolismo , Humanos , Glomérulos Renales/citología , Glomérulos Renales/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
Ovarian granulosa cells synthesize anticoagulant heparan sulfate proteoglycans (aHSPGs), which bind and activate antithrombin III. To determine if aHSPGs could contribute to the control of proteolytic activities involved in follicular development and ovulation, we studied the pattern of expression of these proteoglycans during the ovarian cycle. aHSPGs were localized on cells and tissues by (125)I-labeled antithrombin III binding followed by microscopic autoradiography. Localization of aHSPGs has shown that cultured granulosa cells, hormonally stimulated by gonadotropins to differentiate in vitro, up-regulate their synthesis and release of aHSPGS: In vivo, during gonadotropin-stimulated cycle, aHSPGs are present on granulosa cells of antral follicles and are strongly labeled in preovulatory follicles. These data demonstrate that aHSPG expression in the ovarian follicle is hormonally induced to culminate in preovulatory follicles. Moreover, we have shown that five heparan sulfate core proteins mRNA (perlecan; syndecan-1, -2, and -4; and glypican-1) are synthesized by granulosa cells, providing attachment for anticoagulant heparan sulfate chains on the cell surface and in the extracellular matrix. These core proteins are constantly expressed during the cycle, indicating that modulations of aHSPG levels observed in the ovary are likely controlled at the level of the biosynthesis of anticoagulant heparan sulfate glycosaminoglycan chains. This expression pattern enables aHSPGs to focus serine protease inhibitors in the developing follicle to control proteolysis and fibrin formation at ovulation.
Asunto(s)
Anticoagulantes/metabolismo , Fase Folicular , Células de la Granulosa/metabolismo , Proteoglicanos de Heparán Sulfato/metabolismo , Animales , Autorradiografía , Secuencia de Bases , Cartilla de ADN , Femenino , Proteoglicanos de Heparán Sulfato/genética , Radioisótopos de Yodo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
BACKGROUND: Lymphocytes are involved in the physiopathologic mechanism of idiopathic nephrotic syndrome (INS). We have recently demonstrated that plasma from patients with INS decreases human glomerular epithelial cell (GEC) glycosaminoglycans (GAGs), particularly heparan sulfates (HS) in vitro. In this study we investigate the effect of peripheral blood lymphocytes (PBL) from INS patients on glomerular cell GAG and HS. METHODS: Human GECs were cultured with total peripheral blood mononuclear cells (PBMCs), PBL, and monocytes from patients and controls. The amounts of GAG and HS were assessed using a cationic membrane after metabolic labeling. RESULTS: In coculture with GECs, mononuclear cells from controls decreased total epithelial cell GAG (-30% with PBMC, P < 0.05; -25% with PBL, P < 0.02; -19% with monocytes, P < 0.05). Particularly HSs were decreased (-36% with PBMC, P < 0.05; -27% with PBL, P < 0.02; and -19% with monocytes, P < 0.05). When GECs were in coculture with PBL from INS patients, the decrease in GAG and HS was significantly greater in comparison to control PBL (-10%, P < 0.02; -10%, P < 0.02, respectively, for GAG and HS). Moreover, supernatants of stimulated PBMCs from patients decreased also GAG and HS in comparison with controls (-13%, P < 0.02; -15%, P < 0.02, respectively, for GAG and HS). CONCLUSION: These data provide direct evidence that PBLs from INS patients are able to decrease GEC HS as previously shown with plasma from patients. This might be instrumental in the onset of albuminuria.
Asunto(s)
Heparitina Sulfato/antagonistas & inhibidores , Glomérulos Renales/metabolismo , Linfocitos/fisiología , Síndrome Nefrótico/metabolismo , Células Cultivadas , Niño , Sulfatos de Condroitina/metabolismo , Glicosaminoglicanos/química , Glicosaminoglicanos/metabolismo , Humanos , Glomérulos Renales/patología , Monocitos/fisiología , Síndrome Nefrótico/patología , Polímeros/metabolismo , Valores de ReferenciaRESUMEN
Understanding infertility and sterility requires knowledge of the molecular mechanisms underlying sexual reproduction. We have found that male mice deficient for the gene encoding the protease inhibitor protease nexin-1 (PN-1) show a marked impairment in fertility from the onset of sexual maturity. Absence of PN-1 results in altered semen protein composition, which leads to inadequate semen coagulation and deficient vaginal plug formation upon copulation. Progressive morphological changes of the seminal vesicles also are observed. Consistent with these findings, abnormal PN-1 expression was found in the semen of men displaying seminal dysfunction. The data demonstrate that the level of extracellular proteolytic activity is a critical element in controlling male fertility.
Asunto(s)
Proteínas Portadoras/fisiología , Infertilidad Masculina/metabolismo , Inactivadores Plasminogénicos/fisiología , Inhibidores de Serina Proteinasa/fisiología , Precursor de Proteína beta-Amiloide , Animales , Proteínas Portadoras/genética , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Nexinas de Proteasas , Receptores de Superficie Celular , Semen/metabolismo , Proteínas de Plasma Seminal/metabolismo , Vesículas Seminales/metabolismo , Serpina E2 , Espermatozoides/metabolismo , Espermatozoides/fisiología , Vagina/fisiologíaRESUMEN
The aims of this review are to evaluate the morphological differences between 'round cells' of spermatogenic and non-spermatogenic origin in semen. The latter group includes inflammatory cells like neutrophils, lymphocytes, and macrophages, and epithelial cells. A comparison was made between non-spermatogenic cells in semen samples and inflammatory cells in blood smears, using various staining procedures commonly used in routine andrology laboratories. The result presented in this review confirmed previously published data. In blood smears as well as in semen samples, only neutrophil leukocytes (both eosinophilic and basophilic) showed a positive reaction when exposed to the peroxidase stain. Lymphocytes, macrophages and other 'round cells' such as epithelial cells and spermatogenesis cells remained negative. It could be concluded that the neutrophil polymorphonuclear leukocytes were the only 'round cells' showing a positive reaction in the semen samples. The presence of specifically stained neutrophils in semen was considered to be compatible with an infection and/or a subsequent inflammatory reaction in the male genital tract. The potential influence of inflammatory cells in the sperm samples on infertility/subfertility is discussed. However, the question of determining if morphologically abnormal, degenerated spermatids are still capable of fertilizing an oocyte in vitro is not addressed in this review.
Asunto(s)
Semen/citología , Animales , Tamaño de la Célula , Células Epiteliales/citología , Humanos , Macrófagos/citología , Masculino , Monocitos/citología , Neutrófilos/citología , Próstata/citología , Vesículas Seminales/citología , EspermatogénesisRESUMEN
The physiopathological mechanisms of idiopathic nephrotic syndrome involve a circulating plasma factor and a decrease in HS in the glomerular basement membrane. Previous studies have demonstrated that plasma from patients with INS decreases glomerular cell HS in vitro. We examined the involvement of cyclic adenosine monophosphate (cAMP) in this interaction. We studied the effect of plasma from patients with INS on mesangial cell cAMP. We also determined mesangial cell HS when cAMP levels were modified using a cationic membrane after metabolic labeling. Cellular cAMP levels increased significantly when mesangial cells were incubated with plasma from patients with INS in comparison with control plasma (+77%, P = 0.01). Forskolin and IBMX, which increased cellular cAMP, decreased HS levels (-21 +/- 9% and -15 +/- 6% respectively, P < 0.05 for both), whereas dideoxyadenosine, which decreased cellular cAMP, increased HS levels (+24 +/- 7%, P < 0.05). Plasma from patients with INS decreased glomerular cell HS in comparison with control plasma (-34 +/- 8%, P < 0,05). This effect was abolished when cells were preincubated with ddAdo to prevent an increase in cAMP levels. We conclude that in mesangial cells, plasma from patients with INS increases cAMP levels, and that cAMP mediates a decrease in HS levels. Moreover, the action of plasma from patients on HS was inhibited when an increase in cAMP was prevented. cAMP may therefore be instrumental in the negative effect of the plasma factor on mesangial cell HS.
Asunto(s)
AMP Cíclico/metabolismo , Mesangio Glomerular/metabolismo , Heparitina Sulfato/biosíntesis , Síndrome Nefrótico/metabolismo , Transducción de Señal , 1-Metil-3-Isobutilxantina/farmacología , Adulto , Animales , Antimetabolitos/farmacología , Células Cultivadas , Niño , Preescolar , Colforsina/farmacología , Creatinina/metabolismo , Didesoxiadenosina/farmacología , Humanos , Inhibidores de Fosfodiesterasa/farmacología , Plasma/fisiología , Ratas , Ratas Sprague-Dawley , Estadísticas no Paramétricas , Orina/fisiologíaRESUMEN
In vivo and in vitro findings have shown that plasma of patients with idiopathic nephrotic syndrome (INS) contain factors that increase glomerular permeability to proteins. The effects of these factors on proteoglycan synthesis by glomerular cells are unknown. To investigate the effect of plasma from patients with INS (n = 23) and other glomerulopathies (n = 12) on the amount of proteoglycans synthesized by cultured rat mesangial cells and human glomerular epithelial cells, glomerular cells were cultured for 24 h with plasma from patients or control subjects, and incorporation of Na2(35)SO4 in chondroitin dermatan sulfate and heparan sulfate was assessed using a cationic nylon membrane. The mean ratio of glycosaminoglycan produced by rat mesangial cells when in contact with plasma (5%) from INS patients to the amount produced when in contact with control plasma was 0.70+/-0.06. The mean ratio of heparan sulfate was 0.58+/-0.08. The decrease of heparan sulfate production was present in the cellular and in the extracellular fraction. It was observed when the cells were in contact with plasma from patients in relapse but not when in remission. No decrease of heparan sulfate production was observed with four of the five patients with membranous glomerulonephritis (ratio of 1.27+/-0.03), IgA nephropathy (n = 5, ratio of 1.27+/-0.03), and membranoproliferative glomerulonephritis (n = 2, ratio of 1.39+/-0.34). When human glomerular epithelial cells were exposed to 5% plasma from INS patients in relapse (n = 9), the mean ratio of heparan sulfate was 0.62+/-0.06 in the cellular fraction and 0.72+/-0.08 in the medium. When in contact with plasma from patients in remission, no difference of glycosaminoglycan production was observed. A factor present in plasma from patients with INS during initial episodes or relapses is able to decrease the proteoglycan production of glomerular cells.
Asunto(s)
Sangre/metabolismo , Glomérulos Renales/metabolismo , Síndrome Nefrótico/sangre , Proteoglicanos/biosíntesis , Animales , División Celular , Supervivencia Celular , Células Cultivadas , Medios de Cultivo , Ensayo de Inmunoadsorción Enzimática , Glomerulonefritis Membranosa/sangre , Humanos , Glomérulos Renales/citología , Ratas , Albúmina Sérica/metabolismoAsunto(s)
Neoplasias Óseas/radioterapia , Neoplasias Óseas/secundario , Neoplasias de la Mama/patología , Dolor/etiología , Radioisótopos de Estroncio/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias Óseas/complicaciones , Femenino , Humanos , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
Anticoagulant heparan sulfate proteoglycans endow the vascular endothelium with antithrombotic properties, but their role outside the vascular bed is unknown. Granulosa cells form an avascular compartment in the ovarian follicle, in which a heparin-like activity has been described. At ovulation extravascular coagulation occurs around ovulatory follicles, and after expulsion of the oocyte, a fibrin clot forms in the antral cavity. Granulosa cells synthesize two major heparan sulfate proteoglycans, whose anticoagulant nature has not been investigated. The purpose of this study was to characterize anticoagulant heparan sulfate proteoglycans synthesized by rat ovarian granulosa cells. Affinity purified 35S-labeled anticoagulant heparan sulfate glycosaminoglycans represent 6.5% of the total heparan sulfate synthesized, and they contain 13% 3-O-sulfated disaccharides that are markers of the antithrombin-binding site of heparin. The biological activity of granulosa cell heparan sulfate proteoglycans was demonstrated by their ability to bind antithrombin and to accelerate the formation of thrombin-antithrombin complexes. The impact of hormonal stimulation on granulosa cell anticoagulant heparan sulfate proteoglycans was studied using 125I-antithrombin binding assays. Follicle-stimulating hormone induced a redistribution of anticoagulant heparan sulfate proteoglycans from the granulosa cell layer to the culture medium, indicating that their distribution could be modulated according to the stage of follicular development. These results suggest that anticoagulant heparan sulfate might be critically located in the follicle to maintain fluidity around the oocyte until its expulsion at ovulation.
Asunto(s)
Anticoagulantes/metabolismo , Células de la Granulosa/metabolismo , Heparitina Sulfato/biosíntesis , Proteoglicanos/biosíntesis , Animales , Antitrombina III/metabolismo , Adhesión Celular , Células Cultivadas , Cromatografía de Afinidad , Disacáridos/análisis , Electroforesis en Gel de Poliacrilamida , Endotelio/metabolismo , Estradiol/farmacología , Femenino , Hormona Folículo Estimulante/farmacología , Células de la Granulosa/efectos de los fármacos , Proteoglicanos de Heparán Sulfato , Heparitina Sulfato/aislamiento & purificación , Técnicas In Vitro , Peso Molecular , Proteoglicanos/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Sulfatos/metabolismo , Trombina/metabolismoRESUMEN
The post-coital test involves direct microscopic examination of sperm number and motility in cervical mucus. The results depend on the quality of the mucus and the distribution of spermatozoa within the sample. To progress from such qualitative data to quantitative measurements of the spermatozoa present in post-coital mucus, we have developed methods to measure sperm concentrations in enzymatically liquefied post-coital cervical mucus. The mucus score and sperm motility were measured prior to mucus liquefaction, and, together with sperm concentration, they allowed the calculation of the total number of motile spermatozoa present. A combination of bromelin and glycosidases proved to be more efficient in achieving reliable mucus liquefaction than treatment with bromelin alone, and was used to liquefy a series of 36 post-coital test samples. Total sperm numbers ranged between 19 x 10(3) and 16.8 x 10(6). Of the samples, 75% contained < 3 x 10(6) spermatozoa, and 39% contained < 1 x 10(6) spermatozoa. Sperm motility was very high in these samples, except for a distinct subset of samples (19%) in which the total sperm motility was markedly decreased ( < 20%). The measurement of sperm concentration in liquefied cervical mucus will help to determine normal values for the post-coital test, and to estimate the number of motile spermatozoa reaching the upper female genital tract.
Asunto(s)
Moco del Cuello Uterino/citología , Coito , Recuento de Espermatozoides , Bromelaínas/farmacología , Moco del Cuello Uterino/efectos de los fármacos , Femenino , Glicósido Hidrolasas/farmacología , Humanos , Masculino , Factores de TiempoRESUMEN
The post-coital test evaluates the penetration of spermatozoa into cervical mucus; it relies on subjective measurements and therefore lacks precision. Enzymatic liquefaction of cervical mucus allows sperm concentration to be measured in post-coital test samples, but the reliability of such measurements is not known. Donor cervical mucus was used as a model to test the accuracy and sensitivity of sperm quantification in liquefied cervical mucus. Donor cervical mucus was dissolved by enzymatic treatments in the presence of known numbers of spermatozoa and the recovery of sperm cells was assessed after liquefaction of the samples. Enzymatic treatment of cervical mucus with a combination of bromelin and glycosidases resulted in reliable and fast liquefaction of the samples. The accuracy of sperm concentration measurements was 89 +/- 10% (mean +/- SD, n = 50), and the sensitivity limits were 1 x 10(6) and 0.2 x 10(6) spermatozoa/ml for quantitative concentration measurement and qualitative sperm detection respectively. This study demonstrates that liquefaction of cervical mucus by combined protease and glycosidases allows accurate and sensitive determination of sperm concentration in the sample. Therefore we believe that valuable data can be obtained for sperm concentration and total sperm counts in post-coital tests, that should help to improve the reliability of the post-coital test.
Asunto(s)
Moco del Cuello Uterino/citología , Endopeptidasas/farmacología , Glicósido Hidrolasas/farmacología , Recuento de Espermatozoides , Donantes de Tejidos , Moco del Cuello Uterino/efectos de los fármacos , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , Sensibilidad y EspecificidadRESUMEN
The most important goal of fertility investigation is to identify the cause(s) of infertility and to prescribe adequate therapy. The couple should be treated as a single unit as each partner contributes a share to the infertility potential of the couple. Evaluation should begin with the taking of a detailed history and a complete physical examination of both partners, which may point the investigation in a particular direction. However, other pertinent fertility factors should not be overlooked. A standardized and comprehensive approach to the investigation of infertility is proposed and is presented as a series of flow charts.
Asunto(s)
Infertilidad Femenina/etiología , Infertilidad Masculina/etiología , Algoritmos , Amenorrea/complicaciones , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Masculino , Anamnesis , Ciclo Menstrual , Enfermedades Profesionales/complicaciones , Oligospermia/complicaciones , Examen Físico , Guías de Práctica Clínica como Asunto , Semen/química , Semen/citología , Enfermedades de Transmisión Sexual/complicaciones , Tirotropina/sangreRESUMEN
We have investigated the characteristics of clonal L cell mutant VI-7 that has previously been demonstrated to exhibit reduced levels of cell surface proteoglycans containing heparan sulfate (HS) with regions of defined monosaccharide sequence that interact with antithrombin (HSact) (de Agostini, A. L., Lau, H. K., Leone, C., Youssoufian, H., and Rosenberg, R. D. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 9784-9788). Pulse labeling revealed that the synthesis of HSact in mutant cells, as compared to wild-type cells, was reduced by 5-7-fold, which is identical to the previously observed reduction in cell surface-bound antithrombin. This alteration is independent of growth state since production of HSact by mutant cells, as compared to wild-type cells, is decreased to a similar extent in exponentially growing and post-confluent cultures. The synthetic defect was specific for HSact since production of total HS and chondroitin sulfate by mutant cells, as compared to wild-type cells, was identical in magnitude. The synthetic abnormality is not due to an alteration in core protein since complementation was not observed when mutant cells were stably transfected with the epitope-tagged ryudocan cDNA which can initiate HSact production. Structural analyses revealed that HS from mutant cells, as compared to wild-type cells, exhibited normal molecular weight, extent and distribution of sulfate, and disaccharide composition, which indicate that the mutation did not affect HS biosynthetic enzymes. Together, the data suggest that mutant VI-7 is defective in a regulatory component which directly or indirectly coordinates HS biosynthetic enzymes to specifically generate the defined monosaccharide sequence of HSact.
Asunto(s)
Anticoagulantes/metabolismo , Heparitina Sulfato/biosíntesis , Animales , Células L , Glicoproteínas de Membrana , Ratones , Mutación , Proteoglicanos/biosíntesis , Sindecano-4RESUMEN
The heparan sulfate proteoglycans that bind and activate antithrombin III (aHSPGs) are synthesized by endothelial cells as well as other nonvascular cells. We determined the amounts of cell surface-associated and soluble aHSPGs generated by the rat fat pad endothelial (RFP) cell line and the fibroblast (LTA) cell line. The RFP cells exhibit higher levels of cell surface-associated aHSPGs as compared to LTA cells, whereas LTA cells release larger amounts of soluble aHSPGs as compared to RFP cells. After confluence RFP cells show an increase in both cell surface-associated and soluble aHSPGs. In contrast, postconfluent LTA cells maintain a constant level of cell surface-associated and soluble aHSPGs. These observations indicate that different cell types can preferentially accumulate aHSPGs as cell surface-associated or soluble forms which could reflect alternate biological functions.
Asunto(s)
Endotelio Vascular/metabolismo , Fibroblastos/metabolismo , Heparitina Sulfato/química , Proteoglicanos/biosíntesis , Animales , Línea Celular , Colodión , Medios de Cultivo , Medios de Cultivo Condicionados , Radioisótopos de Yodo , Cinética , Ratones , Ratas , Solubilidad , Radioisótopos de AzufreRESUMEN
Measurement of radioactivity levels in the urine of patients undergoing strontium-89 therapy can be used to evaluate the efficacy of therapy or for patient's management (radiation protection rules and waste disposal). The complex beta counting procedures require extensive sample manipulation during preparation of the liquid scintillation cocktail. The high activity levels that may be found permit one to measure 89Sr activity sample by counting the low yield gamma emission (909 keV) of the radionuclide. However, the contamination of 85Sr due to the reaction for producing 89Sr, if measured with sufficient precision, could be used to evaluate 89Sr activity in urine samples. In other words, the contaminant 85Sr can be used as a tracer of 89Sr. This method was tested in four patients and the accuracy was found to be sufficient to obtain the individual time-activity curves of the urinary excretion.
Asunto(s)
Neoplasias Óseas/radioterapia , Neoplasias de la Mama/radioterapia , Neoplasias Primarias Desconocidas/radioterapia , Cuidados Paliativos/métodos , Radioisótopos de Estroncio/uso terapéutico , Neoplasias Óseas/secundario , Femenino , Humanos , Monitoreo Fisiológico , Radioisótopos de Estroncio/orinaRESUMEN
Mammalian cells synthesize heparan sulfate proteoglycans (HSPG) which consist of core proteins with covalently linked glycosaminoglycans (GAGs) of 50-150 disaccharide units. The GAGs exhibit great structural diversity which arise from differing arrangements of alternate disaccharide units. It has been hypothesized that HSPG may be involved in regulating the most basic aspects of cell biologic systems such as adhesion, proliferation and differentiation. However, considerable doubt exists about the specific nature of the above interactions because of a failure to isolate GAGs of unique monosaccharide sequence with appropriate biologic activities. We have demonstrated that mouse LTA cells synthesize cell surface heparan sulfate proteoglycans with regions of defined monosaccharide sequence that specifically interact with antithrombin (HSPGact). However, it remains unclear how HSPGact can be generated by a biosynthetic pathway with no simple template for directing the ordered assembly of monosaccharide units. To examine this issue, we treated LTA cells with ethylmethane sulfonate and then identified mutants that exhibit decreased antithrombin binding to heparan sulfate chains but possess no gross defects in glycosaminoglycan biosynthesis. After screening 40,000 colonies, we isolated 7 stable mutants which synthesize 8-27% of the wild type HSPGact but produce normal amounts of other HSPG. These mutants are recessive in nature, and fall into at least two different complementation groups. The delineation of the molecular basis of these defects should greatly improve our understanding of how cells synthesize HSPG with regions of defined monosaccharide sequence.