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1.
Clin Oncol (R Coll Radiol) ; 32(4): e102-e110, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31685376

RESUMEN

AIMS: Due to the rarity and varied natural history of desmoid-type fibromatosis, evidence-based treatment standards for this disease remain lacking. This study evaluated outcomes in patients with desmoid-type fibromatosis managed at a Canadian institution over two decades. MATERIALS AND METHODS: Records of 227 patients with desmoid-type fibromatosis referred from 1990 to 2013 were retrospectively reviewed to investigate management strategies including active surveillance, surgery, radiation therapy, cryoablation, and systemic therapy, including tamoxifen and chemotherapy. RESULTS: Thirty-two per cent of cases were men, median age 40 years, median tumour size 5.4 cm. Initial treatments were surgery (79%), tamoxifen (13%), radiation therapy (5.0%), chemotherapy (1.8%) and cryoablation (1.2%). Active surveillance was used upfront in 26% of cases, most after 2005. At a median follow-up of 77 months, one patient died of disease, 13 died of unrelated causes and the remainder were alive with no evidence of disease (56%), stable/responding disease (33%) or progressive disease (4%). The recurrence rate was 25% after upfront surgery. Response rates and disease control rates were 40% and 76% for active surveillance; 68% and 96% for radiation therapy; 31% and 67% for tamoxifen; and 53% and 80% for chemotherapy. On univariable analysis, factors associated with a higher recurrence after initial surgery were young age (P = 0.012), male gender (P = 0.012) and extremity location (P = 0.005). On multivariable analysis, only young age was significantly associated with recurrence risk (P = 0.010). CONCLUSIONS: Active surveillance was associated with spontaneous regression and long-term disease control consistent with other studies. Primary radiation therapy appeared to provide a similar response and disease control compared with systemic treatments and may be a viable option for patients who are not candidates for surgery or active surveillance.


Asunto(s)
Fibromatosis Agresiva/terapia , Adulto , Colombia Británica , Femenino , Fibromatosis Agresiva/patología , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Masculino , Estudios Retrospectivos
2.
J Perinatol ; 26(8): 476-80, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16688202

RESUMEN

OBJECTIVE: To compare the work of breathing (WOB) in premature neonates supported with high-flow nasal cannula (HFNC) and nasal continuous positive airway pressure (NCPAP). STUDY DESIGN: Eighteen preterm neonates <2.0 kg on HFNC or NCPAP support were studied in a random order. A ventilator was used to deliver 6 cm H2O of NCPAP with nasal prongs. High-flow nasal cannula delivered with Vapotherm (VAPO) at 3, 4 and 5 l/min was used. Tidal ventilation was obtained using respiratory inductance plethysmography calibrated with face-mask pneumotachography. An esophageal balloon estimated pleural pressure from which changes in end distending pressure were calculated. Inspiratory, elastic and resistive WOB and respiratory parameters were calculated. RESULTS: No differences were found in the WOB for all settings. Changes in end distending pressure did not vary significantly over all device settings except VAPO at 5 l/min. CONCLUSION: In these preterm infants with mild respiratory illness, HFNC provided support comparable to NCPAP.


Asunto(s)
Enfermedades del Prematuro/fisiopatología , Terapia por Inhalación de Oxígeno , Enfermedades Respiratorias/fisiopatología , Trabajo Respiratorio , Presión de las Vías Aéreas Positiva Contínua , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/terapia , Rendimiento Pulmonar , Respiración , Mecánica Respiratoria , Enfermedades Respiratorias/terapia , Volumen de Ventilación Pulmonar
3.
Br J Nutr ; 89(4): 499-508, 2003 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12654168

RESUMEN

A whole-body radioassay procedure was used to assess the retention and apparent absorption by rats of Cd in kernels of durum wheat (Triticum turgidum L. var. durum) harvested from plants grown hydroponically in 109Cd-labelled nutrient solution. Wholegrain wheat, containing 5 micromol Cd (570 microg)/kg dry weight labelled intrinsically with 109Cd, was incorporated into test meals fed to rats that had been maintained on diets containing marginally adequate, adequate or surplus levels of Zn (0.12 mmol (8 mg), 0.43 mmol (28 mg) or 1.55 mmol (101 mg) Zn/kg respectively), and either 0 or 50 g durum wheat/kg. Regardless of diet, all rats consumed about 99 % of the test meal offered. In rats fed diets without wheat, initial Cd absorption averaged 7.7, 4.6 and 2.4 % of the dose when the diet contained 0.12 mmol (8 mg), 0.43 mmol (28 mg) or 1.55 mmol (101 mg) Zn/kg diet respectively. In rats fed wheat-containing diets, initial Cd absorption averaged 3.8 and 2.6 % of the dose when dietary Zn concentration was 0.12 mmol (8 mg) and 0.43 mmol (28 mg)/kg diet respectively. The amount of Cd retained in the body at 15 d postprandial was <2 % of the dose in all rats, and decreased as Zn in the diet increased. Even at 15 d postprandial, 32 to 44 % of the Cd retained in the body was still in the gastrointestinal tract. The results show that: (1) the bioavailability to rats of Cd in wholegrain durum wheat was depressed when wholegrain wheat was part of the regular diet; (2) increased intake of dietary Zn lowered Cd absorption and retention; (3) retention of Cd in the body at 15 d postprandial from diets containing adequate Zn was <1.3 %.


Asunto(s)
Cadmio/administración & dosificación , Dieta , Triticum , Zinc/administración & dosificación , Análisis de Varianza , Animales , Disponibilidad Biológica , Absorción Intestinal , Masculino , Ratas , Ratas Sprague-Dawley , Especificidad de la Especie , Factores de Tiempo , Triticum/genética
4.
Plant Physiol ; 125(1): 456-63, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11154353

RESUMEN

There is considerable variability among wheat (Triticum aestivum L.) cultivars in their ability to grow and yield well in soils that contain very low levels of available Zn. The physiological basis for this tolerance, termed Zn efficiency, is unknown. We investigated the possible role of Zn(2+) influx across the root cell plasma membrane in conferring Zn efficiency by measuring short-term (65)Zn(2+) uptake in two contrasting wheat cultivars, Zn-efficient cv Dagdas and Zn-inefficient cv BDME-10. Plants were grown hydroponically under sufficient and deficient Zn levels, and uptake of (65)Zn(2+) was measured over a wide range of Zn activities (0.1 nM-80 microM). Under low-Zn conditions, cv BDME-10 displayed more severe Zn deficiency symptoms than cv Dagdas. Uptake experiments revealed the presence of two separate Zn transport systems mediating high- and low-affinity Zn influx. The low-affinity system showed apparent K(m) values similar to those previously reported for wheat (2-5 microM). Using chelate buffered solutions to quantify Zn(2+) influx in the nanomolar activity range, we uncovered the existence of a second, high-affinity Zn transport system with apparent K(m) values in the range of 0.6 to 2 nM. Because it functions in the range of the low available Zn levels found in most soils, this novel high-affinity uptake system is likely to be the predominant Zn(2+) uptake system. Zn(2+) uptake was similar for cv Dagdas and cv BDME-10 over both the high- and low-affinity Zn(2+) activity ranges, indicating that root Zn(2+) influx does not play a significant role in Zn efficiency.


Asunto(s)
Triticum/fisiología , Zinc/metabolismo , Transporte Biológico , Pan , Cinética , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Triticum/efectos de los fármacos , Triticum/crecimiento & desarrollo , Zinc/farmacología
5.
Kans Med ; 98(3): 6-9, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9604623

RESUMEN

Coronary artery ectasia is an uncommon expression of coronary artery atherosclerosis and other diseases. It occurs in about 1.4 percent of the adult population. It is not distinguishable from obstructive coronary artery disease in severity of angina, clinical presentation, electrocardiograms, mortality, or outcome of coronary artery surgery. Although there is debate, treatment is indicated in the form of chronic warfarin anticoagulation to prevent coronary thrombus formation and its sequelae. Aspirin therapy may suffice in asymptomatic individuals.


Asunto(s)
Aneurisma Coronario , Anticoagulantes/uso terapéutico , Aneurisma Coronario/tratamiento farmacológico , Aneurisma Coronario/patología , Aneurisma Coronario/fisiopatología , Dilatación Patológica , Femenino , Humanos , Persona de Mediana Edad , Warfarina/uso terapéutico
6.
J Am Diet Assoc ; 97(12): 1389-93, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9404335

RESUMEN

OBJECTIVE: To document and compare nephrologists' and internal medicine physicians' expectations of renal dietitians and general clinical dietitians. DESIGN: Subjects completed a mailed survey. Respondents provided demographic information and used a 5-point Likert scale to note whether each of 14 job functions was appropriate for general clinical dietitians, renal dietitians, or both. SUBJECTS: Five hundred forty-one physicians registered with the Ohio State Medical Board (OSMB) were surveyed. Within this group were 283 nephrologists (the population of nephrologists registered with the OSMB) and 258 internal medicine physicians (selected randomly by the OSMB). A total of 133 physicians (25%) returned the survey; 119 surveys were usable: 70 from nephrologists and 49 from internists. STATISTICAL ANALYSES PERFORMED: A composite variable was created by coding and summing physicians' responses regarding dietitian job functions. This variable was averaged for both physician categories. A t test was conducted to compare composite variable results between the two physician groups. RESULTS: At least 50% of nephrologists and internists agreed that both types of dietitians should conduct nutrition assessments, determine patients' energy needs, evaluate medication-nutrient interactions, recommend diet and tube-feeding orders, instruct patients about physician-ordered diets, and teach nutrition concepts to hospital interns. Few physicians agreed that either type of dietitian should order diets, tube feedings, or diet instructions. APPLICATIONS/CONCLUSIONS: Clinical dietitians can educate physicians about dietitians roles informally in their institutions and formally by supporting programs like The American Dietetic Association Physician Nutrition Education Program. In addition, dietetics educators can hone their students' communication and problem-solving skills to promote positive physician-dietitian interaction.


Asunto(s)
Técnicos Medios en Salud/normas , Dietética/normas , Medicina Interna , Nefrología , Rol del Médico , Habilitación Profesional , Dieta/normas , Dietética/educación , Femenino , Humanos , Medicina Interna/normas , Internado y Residencia , Masculino , Nefrología/normas , Distribución Aleatoria , Encuestas y Cuestionarios
7.
Adv Perit Dial ; 13: 244-8, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9360691

RESUMEN

A quality assessment (QA) activity revealed that the percentage of parathyroid hormone (PTH) levels above 300 micrograms/dL was higher in the peritoneal dialysis (PD) unit than in the hemodialysis (HD) unit (44% vs 27%). To reduce the proportion of patients with a target PTH above 200 micrograms/dL, a protocol that emphasized control of the serum phosphate level, standard pulsed doses of calcitriol, and increased patient education was created for the management of renal osteodystrophy. Serum calcium, phosphate, and PTH levels were obtained according to the protocol from July 1994 through June 1996. The percentage of patients achieving a PTH level below 200 micrograms/dL increased from 40% in June 1994 to 57% in June 1996. Significant differences were found in PTH levels at baseline and at test times 1, 2, and 3. Hypercalcemia (Ca > 12) occurred in 4% of the 532 Ca levels drawn during the study period and were due to breaches of protocol. In conclusion, we have confirmed previous work indicating that pulsed calcitriol can control elevated PTH levels in PD patients. Furthermore, we have developed a protocol that can be used as a QA tool to reduce the prevalence of hyperparathyroidism in the outpatient PD setting without inducing excess hypercalcemia.


Asunto(s)
Calcitriol/administración & dosificación , Hiperparatiroidismo Secundario/prevención & control , Diálisis Peritoneal/efectos adversos , Administración Oral , Calcio/sangre , Humanos , Hiperparatiroidismo Secundario/sangre , Hiperparatiroidismo Secundario/etiología , Hormona Paratiroidea/sangre , Fosfatos/sangre
8.
Am Fam Physician ; 54(8): 2463-72, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8961846

RESUMEN

Gastroesophageal reflux occurs in up to 65 percent of healthy infants. The initial differentiation of physiologic reflux with harmless spitting up from pathologic reflux is often difficult to achieve. Gastroesophageal reflux is caused by transient and intermittent lower esophageal sphincter relaxations unrelated to swallowing. Many tests are available for the diagnosis of gastroesophageal reflux, each with specific indications and limitations. Although no one test is always best, 24-hour esophageal pH monitoring remains the "gold standard" for diagnosis. Its major limitations are its inability to detect reflux for up to two hours following feedings because of the neutralizing effect of the feeding, the lack of correlation with clinical gastroesophageal reflux severity, the expense and the invasive nature of the test. Treatment is determined by the specific presentation. Management of physiologic reflux consists of parental reassurance and counseling about feeding and positioning techniques. Approaches to the management of pathologic reflux range from the use of histamine H2-receptor blockers and prokinetic medications to surgery in severe cases.


Asunto(s)
Reflujo Gastroesofágico , Niño , Preescolar , Reflujo Gastroesofágico/diagnóstico , Reflujo Gastroesofágico/tratamiento farmacológico , Reflujo Gastroesofágico/fisiopatología , Reflujo Gastroesofágico/terapia , Humanos
9.
Arthritis Rheum ; 39(10): 1761-2, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8843870

RESUMEN

The patient described herein had 3 features known to be associated with secondary erythermalgia: 1) onset during pregnancy, 2) hypertension, and 3) verapamil treatment (6). Unusual was the fact that while the patient's condition did not respond to aspirin consistently or completely, the skin biopsy did show arteriolar fibromuscular intimal proliferation, which is usually seen with erythromelalgia. Also unusual was the recurrence of symptoms with a second pregnancy 2 years after the presentation reported herein. The syndrome resolved completely within 1 year of delivery. The platelet count was monitored for 4 year after the initial resolution of symptoms (which included the second pregnancy and its associated recurrence of symptoms) and was never higher than 350 x 10(9)/liter. The literature is confusing in mixing of terminology concerning these 3 clinically similar syndromes. The classifications as outlined herein are the emerging standards. A working knowledge of the definitions of these 3 syndromes is critical for appropriate diagnosis and treatment.


Asunto(s)
Eritromelalgia/diagnóstico , Adulto , Edema/diagnóstico , Eritromelalgia/etiología , Femenino , Pie/irrigación sanguínea , Mano/irrigación sanguínea , Humanos , Dolor/diagnóstico
10.
Am Fam Physician ; 54(5): 1587-91, 1595-6, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8857781

RESUMEN

Transient synovitis is the most common cause of acute hip pain in children three to 10 years of age. Children with this condition typically present with hip pain for one to three days, accompanied by limping or the refusal to bear weight. Transient synovitis has an uncertain etiology and remains a diagnosis of exclusion. First, septic arthritis must be ruled out, since femoral head destruction, degenerative arthritis and permanent deformity can occur if septic arthritis is not treated promptly. Septic arthritis should be suspected in a patient with severe pain or spasm on hip movement or palpation, a temperature higher than 37.5 degrees C (99.5 degrees F) and an erythrocyte sedimentation rate of 20 mm per hour or greater. Hip aspiration is the diagnostic procedure of choice if septic arthritis is suspected. Treatment of transient synovitis consists of bed rest and nonsteroidal anti-inflammatory drugs, with regular temperature checks to exclude the onset of fever. If significant pain and limping persist seven to 10 days after the initial presentation, the patient should be reevaluated.


Asunto(s)
Articulación de la Cadera , Dolor/etiología , Sinovitis/diagnóstico , Artritis Infecciosa/diagnóstico , Niño , Diagnóstico Diferencial , Articulación de la Cadera/diagnóstico por imagen , Humanos , Radiografía , Sinovitis/complicaciones , Factores de Tiempo , Ultrasonografía
11.
Plant Physiol ; 103(3): 963-969, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12231994

RESUMEN

Protoplasts isolated from maize (Zea mays L.) suspension cells were used to study transport of paraquat. [14C]Paraquat uptake was measured in 400-[mu]L centrifuge tubes using silicon oil centrifugation techniques. Approximately 50% of accumulation from a 100 [mu]M paraquat solution occurred in the first 10 s, and net accumulation reached a maximum after about 10 min. Membrane binding accounted for about 30% of apparent accumulation. Concentration-dependent uptake kinetics were characterized by a non-saturating curve, which was resolved into a linear and a saturable component. The Km of the saturable component was 132 [mu]M, and the Vmax was 0.512 nmol [mu]L of protoplasts-1 min-1. In the absence of sucrose, the Vmax of the saturable component was reduced by 52%, suggesting that paraquat uptake across the plasmalemma is energy dependent. Measurement of concentration-dependent binding of paraquat to burst protoplasts showed a linear response. This suggests that the linear component from intact protoplast concentration kinetics represented paraquat binding to the plasmalemma surface. Calcium inhibited the saturable component, and this inhibition was shown by Lineweaver-Burk analysis to be noncompetitive. Putrescine, a divalent cationic polyamine with a charge distribution similar to that of paraquat, competitively inhibited paraquat uptake. These results show that paraquat transport characteristics at the plasmalemma of maize protoplasts are similar to those reported earlier for paraquat transport in roots of intact maize seedlings.

12.
Plant Physiol ; 102(2): 467-472, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12231834

RESUMEN

Efflux analysis conducted after five loading periods of various lengths (2, 6, 12, 18, or 24 h) was used to investigate uptake, compartmentation, and translocation of [14C]paraquat in maize (Zea mays L.) seedlings. The time course for net paraquat uptake (paraquat concentration in uptake solution = 25[mu]M) into maize roots was linear (56.7 nmol g-1 root fresh weight h-1) for 24 h. Estimates of changes in paraquat content in the vacuole, cytoplasm, and cell wall after 2-, 6-, 12-, 18-, and 24-h loading periods indicated that the cell wall saturated rapidly, whereas accumulation of paraquat into the vacuole increased linearly (12.4 nmol g-1 root fresh weight h-1) over 24 h. In contrast to vacuolar accumulation, cytoplasmic paraquat content appeared to approach saturation. The half-time for paraquat efflux from the cell wall (16.6 min [plus or minus] 1.2 SD) and cytoplasm (58.8 min [plus or minus] 8.9 SD remained relatively constant regardless of the length of the loading period, whereas the half-time for efflux from the vacuole was considerably longer and increased linearly with increased loading time (6.1-18.7 h). The time course for paraquat translocation to the shoot was linear within a 24-h exposure to radiolabeled herbicide, but translocation did not begin until 5 h after initiation of treatment. The experimental approach used in these experiments provides a valuable method for examining the movement of paraquat in maize seedlings. Results indicate that the herbicide slowly accumulates in the vacuole of root cells but is also translocated to the shoot.

13.
Plant Physiol ; 99(4): 1400-5, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16669051

RESUMEN

Interactions between absorption of paraquat and the polyamines putrescine, cadaverine, and spermine in roots of intact maize (Zea mays L. cv 3377 Pioneer) seedlings were examined. Concentration-dependent kinetics for paraquat and putrescine influx were similar and both kinetic curves could be resolved into a linear and a saturable component. The linear component was previously shown to represent cell wall/membrane binding. The saturable components for paraquat and putrescine uptake, which represent influx across the plasmalemma, had K(m) values of 98 and 120 micromolar, respectively, and V(max) values of 445 and 456 nanomoles per gram fresh weight per hour, respectively. Lineweaver-Burk transformation of the saturable component of paraquat influx in the presence of varying concentrations of putrescine indicated that the diamine competitively inhibited the saturable component of paraquat uptake. Reciprocal experiments similarly demonstrated that paraquat competitively inhibited the saturable component of putrescine uptake. Competitive inhibition of both paraquat and putrescine influx could also be demonstrated with the diamine cadaverine, which has a charge distribution similar to that of paraquat and putrescine. In contrast, the larger, tetravalent polyamine spermine appeared to noncompetitively inhibit the influx of paraquat and putrescine. These results strongly suggest that paraquat enters maize root cells via a carrier system that normally functions in the transport of diamines with a charge distribution similar to that of paraquat.

14.
Plant Physiol ; 99(2): 508-14, 1992 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16668915

RESUMEN

The specificity and regulation of putrescine transport was investigated in roots of intact maize (Zea mays L.) seedlings. In concentration-dependent transport studies, the kinetics for putrescine uptake could be resolved into a single saturable component that was noncompetitively inhibited by increasing concentrations of Ca(2+) (50 micromolar to 5 millimolar). Similarly, other polyvalent cations, including Mg(2+) (1.8 millimolar) and La(3+) (200 micromolar), almost completely abolished the saturable component for putrescine uptake. This suggests that putrescine does not share a common transport system with other divalent or polyvalent inorganic cations. Further characterization of the putrescine transport system indicated that 0.3 millimolar N-ethyl-maleimide had no effect on putrescine uptake, and 2 millimolar p-chloromercuribenzene sulfonic acid only partially inhibited transport of the diamine (39% inhibition). Metabolic inhibitors, including carbonylcyanide-m-chlorphenylhydrazone (20 micromolar) and KCN (0.5 millimolar), also partially inhibited the saturable component for putrescine uptake (V(max) reduced 48-60%). Increasing the time of exposure to carbonylcyanide-m-chlorphenylhydrazone from 30 minutes to 2 hours did not significantly increase the inhibition of putrescine uptake. Electrophysiological evidence indicates that the inhibitory effect on putrescine uptake by these inhibitors is correlated to a depolarization of the membrane potential, suggesting that the driving force for putrescine uptake is the transmembrane electrical potential across the plasmalemma.

15.
Plant Physiol ; 98(2): 611-20, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16668685

RESUMEN

Putrescine metabolism, uptake, and compartmentation were studied in roots of hydroponically grown intact maize (Zea mays L.) seedlings. In vivo analysis of exogenously applied putrescine indicated that the diamine is primarily metabolized by a cell wall-localized diamine oxidase. Time-dependent kinetics for putrescine uptake could be resolved into a rapid phase of uptake and binding within the root apoplasm, followed by transport across the plasma membrane that was linear for 30 to 40 minutes. Concentration-dependent kinetics for putrescine uptake (between 0.05 and 1.0 millimolar putrescine) appeared to be nonsaturating but could be resolved into a saturable (V(max) 0.397 micromoles per gram fresh weight per hour; K(m) 120 micromolar) and a linear component. The linear component was determined to be cell wall-bound putrescine that was not removed during the desorption period following uptake of [(3)H]putrescine. These results suggest that a portion of the exogenously applied putrescine can be metabolized in maize root cell walls by diamine oxidase activity, but the bulk of the putrescine is transported across the plasmalemma by a carrier-mediated process, similar to that proposed for animal systems.

16.
Plant Physiol ; 94(3): 1295-300, 1990 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16667832

RESUMEN

Triazine-resistant plants grown under moderate to high photon flux density (PFD) conditions exhibit decreased photon yield, decreased light-saturated O(2) evolution and slower growth than triazine-susceptible plants. In this study we tested the hypothesis that the comparable growth previously observed in resistant and susceptible Brassica napus L. lines grown under low PFD was accompanied by comparable photon yield and light-saturated O(2) evolution. We measured photon yield, O(2) flash yield, fluorescence decay kinetics, fluorescence transient kinetics, and quenching components, F(v)/F(m) and light saturated O(2) evolution in leaf disks of low PFD-grown triazine-resistant and susceptible B. napus isogenic lines. Results indicated that slow electron transfer from the primary to secondary quinone electron acceptors of photosystem II was still present in the resistant line but photon yield and light-saturated O(2) evolution were similar in the two B. napus lines. We conclude that the alteration in the D1 protein that confers resistance does not necessarily cause decreased photosynthetic performance. Decreased photon yield in resistant plants grown at high PFD is not a direct consequence of the alteration in D1, but represents secondary damage.

17.
Plant Physiol ; 94(3): 1301-7, 1990 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16667833

RESUMEN

Triazine-resistant and -susceptible Brassica napus L. plants grown under low photon flux density (PFD) have previously been shown to exhibit a similar photon yield. In contrast, high PFD-grown resistant plants have a lower photon yield than high PFD-grown susceptible plants (JJ Hart, A Stemler [1990] Plant Physiol 94: 1295-1300). In this work we tested the hypothesis that high PFD can induce a differential decrease in photon yield in low PFD-grown plants. We measured photon yield, variable fluorescence/maximum fluorescence, and O(2) flash yield in low PFD-grown resistant and susceptible leaf discs before and after exposure to high PFD exposure. The results demonstrated that high PFD exposure results in a greater decrease in photosystem II (PSII) activity in resistant plants. Characteristics of recovery and other evidence suggest that the differential decrease in PSII efficiency in resistant leaf discs is caused by photoinhibitory damage. We propose that the differential reduction in photon yield and photosynthesis often observed in resistant plants is the result of increased sensitivity to photoinhibition.

18.
Br J Hosp Med ; 44(1): 34-7, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1975756

RESUMEN

In terms of both nosology and treatment the paranoid states have long proved a thorny but irresistible enigma to psychiatrists. Recent evidence suggests that at least one of these conditions, paranoia, not only may be eminently treatable, but also merits serious consideration as a clinical entity distinct from other functional psychoses.


Asunto(s)
Trastornos Paranoides/clasificación , Adulto , Anciano , Antipsicóticos/uso terapéutico , Femenino , Humanos , Masculino , Trastornos Paranoides/tratamiento farmacológico , Trastornos Paranoides/terapia , Pimozida/uso terapéutico , Apoyo Social
19.
Am Fam Physician ; 42(1): 163-9, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2195858

RESUMEN

Pheochromocytoma is a rare, potentially lethal cause of hypertension that is surgically reversible. Diagnosis may be difficult, because catecholamine release is often intermittent and the location of the lesion is variable. Management consists of blocking alpha-adrenergic stimulation preoperatively. This controls hypertension both before and during surgery. It also allows expansion of the intravascular volume, preventing postsurgical hypotension. Associated arrhythmias must also be controlled. After surgery, routine evaluation for tumor recurrence is essential.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/diagnóstico , Feocromocitoma/diagnóstico , Neoplasias de las Glándulas Suprarrenales/epidemiología , Neoplasias de las Glándulas Suprarrenales/terapia , Femenino , Humanos , Feocromocitoma/epidemiología , Feocromocitoma/terapia , Cuidados Posoperatorios , Embarazo , Complicaciones Neoplásicas del Embarazo/diagnóstico , Complicaciones Neoplásicas del Embarazo/terapia
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