RESUMEN
Maspin is a non-inhibitory member of the serpin family that affects cell behaviours related to migration and survival. We have previously shown that peptides of the isolated G α-helix (G-helix) domain of maspin show bioactivity. Migration, invasion, adhesion and proliferation of vascular smooth muscle cells (VSMC) are important processes that contribute to the build-up of atherosclerotic plaques. Here we report the use of functional assays of these behaviours to investigate whether other maspin-derived peptides impact directly on VSMC; focusing on potential anti-atherogenic properties. We designed 18 new peptides from the structural moieties of maspin above ten amino acid residues in length and considered them beside the existing G-helix peptides. Of the novel peptides screened those with the sequences of maspin strand 4 and 5 of beta sheet B (S4B and S5B) reduced VSMC migration, invasion and proliferation, as well as increasing cell adhesion. A longer peptide combining these consecutive sequences showed a potentiation of responses, and a 7-mer contained all essential elements for functionality. This is the first time that these parts of maspin have been highlighted as having key roles affecting cell function. We present evidence for a mechanism whereby S4B and S5B act through ERK1/2 and AMP-activated protein kinase (AMPK) to influence VSMC responses.
Asunto(s)
Músculo Liso Vascular/fisiología , Fragmentos de Péptidos/fisiología , Serpinas/fisiología , Secuencia de Aminoácidos , Proliferación Celular/fisiología , Células Cultivadas , Humanos , Integrina beta1/fisiología , Sistema de Señalización de MAP Quinasas , Músculo Liso Vascular/química , Serpinas/química , Transducción de SeñalRESUMEN
INTRODUCTION Magnetic resonance cholangiopancreatography (MRCP) is commonly used to evaluate the biliary tree, although indications for patients who require inpatient imaging are not fully defined. The aim of this study was to evaluate inpatient MRCP performed on surgical patients and to devise a treatment pathway for these patients. MATERIAL AND METHODS All adult inpatient MRCP examinations between January 2012 and December 2013 were reviewed. Demographic, clinical and radiological data were collated. RESULTS During the study period, 271 inpatient MRCP were requested, of which 234 examinations were included. The majority of patients were female (n=140) and the median age was 63 years (range 16-93 years). Surgical admissions accounted for 171 (73%) of cases. Indications for inpatient MRCP include gallstone-related complications (n=173; 74%), malignant process (n=17; 7%) and other indications (n=44; 19%). Overall, inpatient MRCP led to further inpatient interventions in 22% (gallstone group, n=32, 18%; patients with malignancy, n=8, 47%; other indications, n=12, 27%). The median duration of inpatient MRCP from request to examination was 2 days (range 0-15 days) and median reporting after examination was 1 day (range 0-14 days). DISCUSSION AND CONCLUSION Improved access and timely reporting of iMRCP may reduce length of hospital stay. Inpatient MRCP also led to further inpatient interventions, in particular, in patients with malignancy.
Asunto(s)
Neoplasias de los Conductos Biliares/diagnóstico por imagen , Pancreatocolangiografía por Resonancia Magnética , Colelitiasis/diagnóstico por imagen , Eficiencia Organizacional , Hospitalización , Tumor de Klatskin/diagnóstico por imagen , Neoplasias Pancreáticas/diagnóstico por imagen , Servicio de Cirugía en Hospital , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de los Conductos Biliares/cirugía , Colecistectomía Laparoscópica , Colelitiasis/cirugía , Femenino , Humanos , Tumor de Klatskin/cirugía , Tiempo de Internación , Masculino , Persona de Mediana Edad , Neoplasias Pancreáticas/cirugía , Complicaciones Posoperatorias/diagnóstico por imagen , Adulto JovenRESUMEN
INTRODUCTION: Given the importance placed on awareness and participation in research by Speciality and Training organisations, we sought to survey Scottish trainee attitudes to exposure to research practice during training and research in or out of programme. METHODS: An online survey was distributed to core and specialist trainees in general surgery in Scotland. RESULTS: Over a 4-month period, 108 trainees (75 ST/SPRs and 33 CTs) completed the survey. In their current post, most were aware of ongoing research projects (77%) and 55% were aware of trial recruitment. Only 47% attend regular journal clubs. Most believe that they are expected to present (89%) and publish (82%) during training. Most (59%) thought that participation in research is well supported. 57% were advised to undertake time out of programme research, mostly by consultants (48%) and training committee (36%). Of the 57 with time out of programme research experience, most did so in early training (37%) or between ST3-5 (47%). 28 out of the 36 (78%) without a national training number secured one after starting research. Most undertook research in a local academic unit (80%) funded by small grants (47%) or internally (33%). Most research (69%) was clinically orientated (13/55 clinical, 25/55 translational). 56% of those completing time out of programme research obtained an MD or PhD. About 91% thought that research was relevant to a surgical career. CONCLUSIONS: Most trainees believe that research is an important part of training. Generally, most trainees are exposed to research practices including trial recruitment. However, <50% attend regular journal clubs, a pertinent point, given the current 'exit exam' includes the assessment of critical appraisal skills.
Asunto(s)
Actitud del Personal de Salud , Investigación Biomédica/educación , Educación de Postgrado en Medicina , Cirugía General/educación , Investigación Biomédica/estadística & datos numéricos , Recolección de Datos , Proyectos Piloto , EscociaRESUMEN
BACKGROUND: Fellowship posts are increasingly common and offer targeted opportunities for training and personal development. Despite international demand, there is little objective information quantifying this effect or the motivations behind undertaking such a post. The present study investigated surgical trainees' fellowship aims and intentions. METHODS: An electronic, 38-item, self-administered questionnaire survey was distributed in the United Kingdom via national and regional surgical mailing lists and websites via the Association of Surgeons in Training, Royal Surgical Colleges, and Specialty Associations. RESULTS: In all, 1,581 fully completed surveys were received, and 1,365 were included in the analysis. These represented trainees in core or higher training programs or research from all specialties and training regions: 66 % were male; the mean age was 32 years; 77.6 % intended to or had already completed a fellowship. Plastic surgery (95.2 %) and cardiothoracic (88.6 %) trainees were most likely to undertake a fellowship, with pediatrics (51.2 %), and urology (54.3 %) the least likely. Fellowship uptake increased with seniority (p < 0.01) and was positively correlated (p = 0.016, r = 0.767) with increasing belief that fellowships are necessary to the attainment of clinical competence, agreed by 73.1 %. Fellowship aims were ranked in descending order of importance as attaining competence, increasing confidence, and attaining subspecialist skills. CONCLUSIONS: Over three-quarters of trainees have or will undertake a clinical fellowship, varying with gender, specialty, and seniority. Competence, confidence, and subspecialty skills development are the main aims. The findings will influence workforce planning, and perceptions that current training does not deliver sufficient levels of competence and confidence merit further investigation.
Asunto(s)
Actitud del Personal de Salud , Educación de Postgrado en Medicina/métodos , Becas , Motivación , Médicos/psicología , Especialidades Quirúrgicas/educación , Adulto , Competencia Clínica , Educación de Postgrado en Medicina/estadística & datos numéricos , Becas/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Reino UnidoRESUMEN
The utility of simulation in surgical training is now well-established, with proven validity and demonstrable transfer of skills to the clinical setting. Through a reduction in the technical learning curve, simulation can prepare surgeons for actual practice and in doing so it has the potential to improve both patient safety and service efficiency. More broadly, multi-disciplinary simulation of the theatre environment can aid development of non-technical skills and assist in preparing theatre teams for infrequently encountered scenarios such as surgical emergencies. The role of simulation in the formal training curriculum is less well-established, and availability of facilities for this is currently unknown. This paper reviews the contemporary evidence supporting simulation in surgical training and reports trainee access to such capabilities. Our national surgical trainee survey with 1130 complete responses indicated only 41.2% had access to skills simulator facilities. Of those with access, 16.3% had availability out-of-hours and only 54.0% had local access (i.e. current work place). These results highlight the paucity in current provision of surgical skills simulator facilities, and availability (or awareness of availability) varies widely between region, grade and specialty. Based on these findings and current best-evidence, the Association of Surgeons in Training propose 22 action-points for the introduction, availability and role of simulation in surgical training. Adoption of these should guide trainers, trainees and training bodies alike to ensure equitable provision of appropriate equipment, time and resources to allow the full integration of simulation into the surgical curriculum.
Asunto(s)
Instrucción por Computador/métodos , Educación de Postgrado en Medicina/métodos , Especialidades Quirúrgicas/educación , Competencia Clínica , Simulación por Computador , Humanos , Sociedades Médicas , Especialidades Quirúrgicas/métodos , Cirugía Asistida por ComputadorRESUMEN
INTRODUCTION: Most studies of haemodialysis (HD) patients compare venous blood samples from controls with samples from the vascular access (VA) of HD patients. We hypothesised that VA samples may be more prothrombotic compared with venous samples. METHODS: Samples were taken simultaneously from the VA and the contralateral antecubital vein, from 26 patients immediately before HD. Platelet function was assessed by (1) flow cytometric measurement of P-selectin expression and fibrinogen binding (±ADP) and 2) Ultegra rapid platelet function assay. Plasma soluble P-selectin, von Willebrand factor antigen, high sensitivity C-reactive Protein (hs-CRP), thrombin-antithrombin III complex and D-dimer measured by ELISA. RESULTS: Thrombin receptor activating peptide-induced platelet aggregation (P < 0.001) and hs-CRP (P < 0.001) were higher in VA compared with venous samples. Unstimulated platelet fibrinogen binding (P = 0.016) and ADP-stimulated P-selectin expression (P = 0.008) were lower in VA compared with venous samples. The significant difference in hsCRP persisted when patients taking and not taking antiplatelet therapy were analysed separately, but platelet activation remained significantly different only in the nonantiplatelet group. CONCLUSION: There are statistically significant differences between sampling sites, although samples from the VA do not appear to be more pro-thrombotic. Future studies comparing HD patients with controls should ensure uniformity of sampling sites to prevent inaccurate conclusions being drawn.
Asunto(s)
Proteína C-Reactiva/metabolismo , Activación Plaquetaria , Diálisis Renal , Trombosis/sangre , Adulto , Anciano , Biomarcadores/sangre , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/metabolismo , Femenino , Pruebas Hematológicas/normas , Humanos , Inflamación/sangre , Masculino , Persona de Mediana Edad , Activación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Factor de von Willebrand/análisis , Factor de von Willebrand/metabolismoRESUMEN
Significant numbers of men with lower urinary tract symptoms (LUTS) also report symptoms of sexual dysfunction (SD). The prevalence of SD in patients referred to a prostate assessment clinic, was assessed using a confidential questionnaire. Fifty-six percent of patients reported difficulties in maintaining an erection and 48% felt that improving their sexual function would benefit their quality of life. None of the referral letters from primary care mentioned symptoms of SD. Patients with LUTS seen in primary and secondary care should be assessed for SD and offered appropriate advice and management.
Asunto(s)
Disfunción Eréctil/epidemiología , Disfunción Eréctil/etiología , Infecciones Urinarias/complicaciones , Anciano , Atención Ambulatoria , Disfunción Eréctil/psicología , Humanos , Masculino , Persona de Mediana Edad , Enfermeras y Enfermeros , Próstata , Calidad de Vida/psicología , Factores de Riesgo , Escocia/epidemiología , Disfunciones Sexuales Fisiológicas , Encuestas y CuestionariosRESUMEN
PURPOSE: Our primary aims were (1) to examine the patency of transposed brachiobasilic (TBB) fistulae compared to arm arteriovenous graft (AVG) without prior transposition, and (2) to examine the patency of AVG with and without prior transposition. METHODS: Single institution; analysis of prospectively collected data between January 2001 and January 2007. Dedicated database and medical records were reviewed and results analyzed with SPSS. RESULTS: Ninety-one patients underwent 111 procedures (52 TBB: 39 AVG as index); 28 TBB failed with 17 (60%) being replaced with an ipsilateral AVG. TBB compared to AVG (without prior TBB) had significantly (log rank <0.05 ) better primary, primary assisted and secondary patency. Secondary patency at 2 yrs was 47% to 33%, respectively. Ipsilateral AVG after TBB to primary AVG had superior patency rates (secondary patency at 2 yrs 52 vs. 33%) but did not reach significance (log rank =0.073). Combined secondary patency of TBB and AVG after TBB was 81% at 2 yrs. CONCLUSIONS: The TBB offers an autogenous fistula in the upper arm which has superior patency rates to an arm AVG. Once a TBB has failed an ipsilateral AVG is technically feasible and may offer better patency than a primary AVG.
Asunto(s)
Brazo/irrigación sanguínea , Derivación Arteriovenosa Quirúrgica/métodos , Diálisis Renal , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Arteria Braquial , Venas Braquiocefálicas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Politetrafluoroetileno , Estudios Prospectivos , Falla de Prótesis , Tasa de Supervivencia , Grado de Desobstrucción VascularRESUMEN
BACKGROUND: The recent liberalisation of public access to information, including surgical performance, emphasises the necessity for accurate data collection. The Information and Statistics Division of the Scottish Executive (ISD) collect such data for each patient episode, but there is concern about the reliability of this information compared with that collected in local surgical departmental audit. AIM: To determine if diagnostic and operative details were consistent between local audited and national non-audited data sets. METHODS: Three surgical units comprising eight consultants were studied. Epidemiological, diagnostic and operative data for each consultant were accessed from the eScrips Internet resource (ISD Data) and from the departmental database. A unique patient number and date of birth matched individual patient episodes and the correlation between datasets graded for accuracy and consistency. RESULTS: 8375 individual data entries were recorded (ISD 4642, local databases 3733). 3402 pairs, 6408 (76.5%) of the total, matched accurately. 742 (16%) of the ISD entries were duplicates, and in 21% of unpaired entries the wrong consultant was recorded. Overall a clinically acceptable match occurred in 86.9% of paired entries for diagnosis and 84.0% for operation. The highest match with ISD data for diagnosis (88.8%) and operation (91.8%) occurred in the unit which holds a weekly audit meeting to validate information. DISCUSSION: There are significant discrepancies in surgical data between the local audit databases and central data. There is significant duplication of entries and inaccurate consultant allocation in ISD data. The promulgation of inaccurate information could threaten reputation or career and clinicians should play a more active role in ensuring clinical data are correct.
Asunto(s)
Recolección de Datos/métodos , Registros Médicos , Bases de Datos Factuales , Control de Formularios y Registros , Humanos , Clasificación Internacional de Enfermedades , Auditoría Médica , Reproducibilidad de los Resultados , EscociaRESUMEN
Testicular ischaemia presenting in the neonatal period is most often attributable to neonatal torsion. We present an unusual case of a male neonate who presented with acute appendicitis within a patent processus vaginalis, causing cord compression and consequent testicular ischaemia.
Asunto(s)
Apendicitis/complicaciones , Hernia Inguinal/complicaciones , Isquemia/etiología , Testículo/irrigación sanguínea , Enfermedad Aguda , Apendicitis/diagnóstico , Apendicitis/cirugía , Diagnóstico Diferencial , Hernia Inguinal/diagnóstico , Hernia Inguinal/cirugía , Humanos , Recién Nacido , Isquemia/fisiopatología , Masculino , Enfermedades RarasRESUMEN
The acoustic technique was used in conjunction with the pressure chamber to determine the tensions causing cavitation of xylem sap in leaves of five woody angiosperms (Acer pseudoplatanus L., Alnus glutinosa L. Gaertn., Eucalyptus globulus Labill., Fraxinus excelsior L. and Rhododendron ponticum L.) and three species of herbs (Lycopersicum esculentum Mill., Plantago major L. and Ricinus communis L.). The results showed leaves of most species to suffer considerably from cavitation at sap tensions of 1.6-3 MPa. Two of the herbs, Lycopersicum and Ricinus, cavitated extensively at sap tensions below 1 MPa. Additional evidence is presented that clicks, detected by acoustic amplification, are caused by cavitation of sap in the xylem conduits. A rapid method is suggested for the determination of sap tensions in cavitating leaves and which is suitable for surveys of the critical sap tension in a large number of species.
RESUMEN
Phloem-sap composition was studied in plants of Ricinus communis L. grown on a waterculture medium. The sap possessed a relatively high K(+):Na(+) ratio and low levels of Ca(2+) and free H(+). Sucrose and K(+) (together with its associated anions) accounted for 75% of the phloem-sap solute potential (Ψs). In plants kept in continuous darkness, a decrease in phloem-sap sucrose levels over 24h was accompanied by an increase in K(+) levels. Measurements of phloem-sap Ψs and xylem water potential (Ψ) indicated that this resulted in a partial maintenance of phloem turgor pressure Ψp. In darkness there was also a marked decrease in the malate content of the leaf tissue, and it is possible that organic carbon from this source was mobilized for export in the phloem. The results support the concept of the phloem sap as a symplastic phase. We interpret the increase in K(+) levels in the phloem in darkness as an osmoregulatory response to conditions of restricted solute availability. This reponse can be explained on the basis of the sucrose-H(+) co-transport mechanism of phloem loading.
RESUMEN
The osmotic characteristics of phloem-sap exudation were examined in soil-grown and watercultured plants of Ricinus communis L. Prolonged exudation occurred from bark incisions in water-cultured plants. Fresh incisions caused large alterations in solute flux, but phloem-sap solute potential Ψs changed by less than ±8% over a period of 7 h. This was associated with a constancy in the levels of sucrose and K(+), the principal solutes in the sap. Studies with foliar-applied tracers and leaf-excision experiments suggested that exudation was maintained by solute loading from mature leaves. A wide range of mass transfer values through the phloem was found, these being a function of exudation rate. We consider that the exudation process possesses essentially similar characteristics to phloem transport in the intact plant. The way in which bark incisions bring about large changes in solute flux is discussed in terms of the physical properties of the sieve-tube system.
RESUMEN
The influence of plant water relations on phloem loading was studied in Ricinus communis L. Phloem transport was maintained in response to bark incisions even at severe water deficits. Water stress was associated with a net increase in the solute content of the sieve tubes, which resulted in maintenance of a positive phloem turgor pressure Ψp. There was a significant increase in solute flux through the phloem with decreasing xylem water potential (Ψ). In addition, sugar uptake by leaf discs was examined in media adjusted to different water potentials with either sorbitol (a relatively impermeant solute) or ethylene glycol (a relatively permeant solute). The limitations in this experimental system are discussed. The results nevertheless indicated that sucrose uptake can be stimulated by a reduction in cell Ψp, but that it is little affected by cell Ψ or solute potential Ψs. On the basis of these data we suggest that sucrose loading is turgor-pressure dependent. This may provide the mechanism by which transport responds to changes in sink demand in the whole plant.
RESUMEN
Solute concentration gradients were studied in Ricinus communis L. stems using refractometry linked with cryoscopic measurements of osmotic pressure. Techniques were developed to study the local composition of sieve-tube sap, effectively isolating bark segments by ring-massage or massage-girdling. In intact plants concentration gradients in stems were found to be steep near leaves, as reported previously, and also near roots. However, when transport from these organs was prevented, the steep gradients disappeared. Apparently they are caused by sap influx from nearby organs into stems during sampling. Concentration gradients in stems proper were almost negligible under standard growing conditions. They became positive (more concentrated above) when photosynthesis was enhanced, and negative in darkness.During exudation, leaves could secrete abundant concentrated sap for long periods. Stems had a similar but more limited capacity to secrete and, to a still lesser extent, roots also. Secretion was triggered even from natural sinks by exudation from an incision. Release from turgor pressure seems responsible rather than dilution of the phloem sap, suggesting that in whole plants a sink induces secretion and pressure-flow from distant sources by regulating the pressure within sieve tubes. The rate of exudation decreased as sap concentration fell, indicating that a reduction in pressure corresponds to assimilate exhaustion.The hydraulic conductivity of bark was not high, but was greater when the bark was secreting solutes. A change in mass-flow conduction between sieve tubes and storage cells is proposed to explain these differences in water permeability.The common assumption that solute concentration gradients correspond to pressure gradients seems inapplicable to whole Ricinus plants. Solute transfer can exceed the water flux so that osmotic equilibrium may not be reached at a particular location. In intact plants, solute gradients probably reflect source and sink activity with the interconnecting sieve tubes behaving rather passively, like pipes with a solute exchange-capacity. Actual pressure differences in sieve tubes are best indicated by sap concentration differences between source and sink. In Ricinus plants 0.5-1 m tall these pressures can be 5-10 bar.
RESUMEN
Acoustic detection has been used to investigate the incidence of cavitation in whole potted Ricinus plants subjected to water stress by withholding water. Cavitation proceeded rather slowly and was detectable before and during wilting. Techniques which restricted water uptake more drastically such as root cooling or overlapping cuts induced more rapid "click" production and wilting; a response already described for excised leaves. When water stress was removed by rewatering, or rewarming a cooled root system, cavitation soon ceased. This response was more sluggish of over-delayed.Cavitation in aging leaves on well watered plants has also been examined. Despite the onset of senescence over many days there was no evidence that dry patches, which often develop extensively, are a consequence of water shortage induced by xylem blockage. Leaves, falling naturally by abscission in still air, were often remarkably turgid with water potentials similar to those of healthy attached leaves. Only after losing water was cavitation apparent, as usual for excised mature leaves. Sometimes more persistent leaves did cavitate in situ, just before abscission, showing that in normal leaves xylem blockage can occasionally precede leaf fall by several hours.
RESUMEN
Phloem exudation from Ricinus has been examined in plants subjected to changes in water balance induced by a number of means. The results have provided a clear demonstration that the phloem system can operate osmotically. When the availability of water in the xylem is reduced by withholding water, the rate of exudation decreases sharply and this is accompanied by a rise in the sap concentration. On removing the water stress, the rate increases rapidly with a corresponding fall in sap concentration.Small variations in water availability do not give significant results and may be buffered by responses from the plant itself. This could also explain the insignificant changes in sap composition during exudation previously reported, where exudation rate, which should bear some relation to sieve tube turgor pressure, seems independent of sap concentration. Fluctuations in exudation rate are large in comparison with the changes in sap concentration when severe water stresses are applied. This result, coupled with the observation that exudation will occur from plants under considerable water stress suggests the operation of a "sugar pump" capable of maintaining a high turgor pressure at the source against a considerable water potential gradient. The main "pump" is probably located in the leaves.Thus interpreted, the results seem to accord with the Münch pressure flow hypothesis in all significant aspects.
RESUMEN
Xylem cavitation has been studied in Ricinus plants using vibration detection to examine its induction by different factors. These observations provide considerable circumstantial evidence in justification of the new technique as already described and further developed. In general cavitation is induced only when the tissue water balance is reduced hydrostatically. Thus cavitation is promoted by intense radiation which enhances transpiration, or alternatively by the blockage of xylem conduits by suspended particles carried in the transpiration stream. In contrast a reduction in radiation, or prevention of transpiration tends to restrict cavitation. Thus cavitation can be prevented by immersing a leaf in liquid paraffin. This technique has been used to see if radioactive bombardment would trigger its induction but no detectable effect has been observed even when exposed to intense radiation.An excised leaf, losing water in air, produces a "click total". On restoration to full turgor by standing the petiole in water it recovers very slowly and subsequently its "click total" is much reduced. If however the newly wilted leaf is allowed to recover in water following gas evacuation treatment the "cavitation total" often approaches the original and the rate of recovery is extremely rapid. Apparently gas emboli develop rapidly in conduits which have cavitated, but they can be removed by vacuum injection: the conduits refill and conduction is restored.
RESUMEN
A study, made on the phloem exudation profiles from Ricinus plants given varying degrees of pre-treatment by massage, has revealed that the profiles are governed by sealing systems of considerable complexity. One of the most interesting profiles observed involves an initial rapid escape of sap from a single cut which ceases after several minutes, then recommences and builds up prior to a second slow decline; this has been called the "rebleed" phenomenon. At least two mechanisms must be postulated to explain this profile satisfactorily.Massage pre-treatment seems to enhance potential exudation quite locally; even half an internode may be treated with little influence on adjacent tissue. The induced build up in potential exudation gradually increased over several days and after suspension of massage declined at a comparable rate. Massage during exudation can be used to stop flow but exudation may recommence after a period, resembling the "rebleed" exudation profile.
RESUMEN
Exudate can be obtained from incisions made in the bark of the stem of actively growing Ricinus plants. (14)C-labelled assimilates from a fed leaf are rapidly detected in the exudate. This movement was both acropetal and basipetal from the fed leaf, at rates of over 100 cm h(-1). Estimated rates within intact plants were 80-84 cm h(-1).In contrast with xylem sap obtained from the same plant, the exudate obtained had an alkaline pH (8.2), a high dry matter content (10-12.5%), high sugar content (8-10%) which was predominantly sucrose; high potassium content (60-80 mM) and low calcium content (0.5-1.0 mM).It is concluded, on the basis of the present evidence, that the exudate is a true sample of the sieve tube sap undergoing translocation.