Biomedical subjects

Satoshi Kuroda

Publications and source records attributed to Satoshi Kuroda.

At least 37 records · Page 2Linked to original sources

PubMed2005

A novel coating biomaterial for intracranial aneurysms: effects and safety in extra- and intracranial carotid artery.

Methyl-2-cyanoacrylate, a widely used material for coating cerebral aneurysm, was recently withdrawn. The aim of the present study was to develop an alternative coating material for cerebral aneurysm, which is safe, effective and stable within the brain. In the first experiment, an aneurysm model of the common carotid artery was produced in a rabbit by the local application of elastase. The aneurysm produced was covered by no material (Group A), a cellulose cotton sheet and conventional methyl-2-cyanoacrylate (Group B), a newly produced polyglycolic acid felt and fibrin glue (Group C), or a cellulose cotton sheet and fibrin glue (Group D). Histological examination showed that the materials resulted in the formation of tight connective tissue around the artery, and that the material was completely replaced by the connective tissue after 12 weeks. This change was found exclusively in Group C, but not in Group A or the other materials, although a temporary thickening of the intima was also observed at the site of the elastase application in Group C. In Group D, a long-term, marked thickening of the intima was observed. In the second experiment, using an intracranial internal carotid artery from a beagle, the applied polyglycolic acid felt and fibrin glue to the intracranial artery induced the formation of connective tissue around the artery that was completely absorbed 16 weeks after surgery. There were no signs of intimal thickening or of adverse reactions in nervous tissue. The present results suggest that polyglycolic acid felt and fibrin glue is a possible candidate for a safe, effective biomaterial to wrap or coat cerebral aneurysm.

Animals↗

PubMed2005

Combined surgical and endovascular treatment of infected pseudoaneurysm after carotid endarterectomy. Case report.

A 67-year-old male presented with a rare pseudoaneurysm caused by infection after carotid endarterectomy (CEA) performed for stenosis of the left internal carotid artery (ICA). Wound infection and recurrent bleeding from the operated ICA developed 1 month after surgery. Serial angiography showed that the post-CEA pseudoaneurysm gradually increased in size. The carotid balloon occlusion test revealed that the patient could not tolerate permanent ICA occlusion because of poorly developed collaterals. Direct surgical exposure of the aneurysm was impossible due to tight adhesion of the surrounding tissue, so common carotid to middle cerebral artery bypass using a radial artery graft was performed followed by ligation of the distal common carotid artery. Subsequently, retrograde blood flow from the ICA to the aneurysm was interrupted by embolization of the external carotid artery coil through the facial artery. Combined surgical and endovascular treatment is a therapeutic option for patients with post-CEA pseudoaneurysm, if either direct or endovascular surgery is unfeasible.

Aged↗

PubMed2005

Prevalence of asymptomatic microbleeds in patients with moyamoya disease.

Basal moyamoya vessels are a potential source of hemorrhage in patients with moyamoya disease, but the etiology remains unclear. Symptomatic hemorrhage resulting from long-standing hemodynamic effects on pathologically dilated, fragile moyamoya vessels may be preceded by asymptomatic microbleeding in adult moyamoya disease patients, regardless of hemorrhagic or ischemic onset. T2*-weighted magnetic resonance (MR) imaging was used to investigate the presence of microbleeds in 27 adult patients with angiographically confirmed moyamoya disease, 21 females and six males aged 18-70 years (mean 40.8 +/- 15.7 years). Clinical diagnosis was intracranial bleeding in six patients, transient ischemic attack or cerebral infarction in 18, and asymptomatic in three. Asymptomatic microbleeds were detected in four of the 27 patients, two of six who initially presented with hemorrhagic events and two of 18 with ischemic onset. These microbleeds were located in the paraventricular white matter, temporal subcortex, and basal ganglia. The presence of microbleeds had no correlation with either patient age or duration from disease onset or diagnosis of disease. A large cohort study is needed to explore the significance of asymptomatic microbleeds in moyamoya disease.

Adolescent↗

PubMed2005

[Carotid occlusive disease presenting with loss of consciousness].

The authors report 9 patients who presented with loss of consciousness (syncope) due to occlusive carotid artery diseases. All patients were males, and their age ranged from 59 to 83 years. The attack was associated with dehydration or hypotension in 5 patients. MRI demonstrated fresh cerebral infarction in the watershed zone. Cerebral angiography revealed occlusion of the unilateral internal carotid artery (ICA) in 7 patients, severe stenosis of the bilateral ICA in one, and occlusion of the unilateral ICA and severe stenosis of the contralateral ICA in one. Single photon emission tomography (SPECT) or positron emission tomography (PET) suggested reduced cerebral perfusion reserve because of inappropriate development of collateral circulation in 4 out of 9 patients. These 4 patients underwent superficial temporal artery to middle cerebral artery anastomosis and/or carotid endarterectomy. Other 5 patients were medically treated. No further episode of syncope occurred in all 9 patients during follow-up periods. The results suggest that occlusive carotid artery diseases should be taken in considerations as a cause of syncope attack.

Aged↗

PubMed2005

[Novel stent/CEA strategy for patients with bilateral carotid artery stenosis and coronary artery disease: report of 2 cases].

Recently, there are increasing numbers of patients with occlusive carotid artery disease and coronary artery disease. Simultaneous or two-staged surgery for both lesions has been recommended for these patients to reduce the incidence of perioperative complications. However, therapeutic options for the patients with bilateral carotid artery stenosis and coronary artery disease have not been established. In this report, we describe two patients who successfully underwent carotid endarterectomy (CEA) and carotid artery stenting (CAS) on each carotid artery in parallel with coronary artery bypass grafts (CABG). A 49-year-old male with severe stenosis of the bilateral internal carotid artery (ICA) and heart failure underwent CAS on the right side. Next day, he successfully underwent CABG and CEA on the left side at the same time. A 62-year-old male with severe stenosis of the bilateral ICA and coronary artery disease underwent CAS on the right side and CEA on the left side with an interval of 7 days. Subsequently, CABG was performed uneventfully. No perioperative complication occurred in either patient. The results suggest that combination therapy of CAS and CEA would be a valuable option for patients with complex carotid/coronary artery diseases.

Adult↗

PubMed2005

[Improvement of cerebral hemodynamic and metabolic parameters in a patient who presented intracranial hypertension due to superior sinus thrombosis after lumbo-peritoneal shunt: case report].

Cerebral hemodynamic and metabolic changes in intracranial hypertension associated with sinus thrombosis have not been well documented. We report pre- and post-treatment changes in cerebral hemodynamic and metabolic parameters in a 50-year-old male who presented intracranial hypertension due to sinus thrombosis, using single-photon emission computed tomography (SPECT) and positron emission tomography (PET). He complained of headache, nausea and double vision and was admitted to our hospital. Neurological examinations on admission revealed papilledema on both sides. Cerebrospinal fluid pressure was 28 mmHg. Cerebral angiography showed occlusion of the superior sagittal sinus and retrograde filling of the ascending cortical veins in the bilateral frontal lobes. 123I-IMP SPECT and 15O-gas PET showed a reduction of cerebral blood flow and oxygen metabolism and an extreme elevation of cerebral blood volume in the bilateral cerebral hemispheres. His complaints resolved after lumbo-peritoneal shunt. Postoperative SPECT/PET studies demonstrated improvement of hemodynamic and metabolic parameters. Intracranial hypertension and associated venous congestion were most likely related to hemodynamic and metabolic abnormalities.

Cerebrospinal Fluid Shunts↗

PubMed2005

[Ruptured aneurysm of bihemispheric anterior cerebral artery bifurcation: case report].

It is well known that distal anterior cerebral artery (ACA) aneurysms are often associated with the anomalies of the ACA, of which azygos ACA and triple ACA have frequently been described. In this report, we present a rare case with a ruptured aneurysm arising from the bifurcation of the bihemispheric ACA, a rare anomaly of the ACA. A 63-year-old male suddenly developed severe headache, consciousness disturbance, and left hemiparesis, and was admitted to our hospital. Plain CT scans revealed subarachnoid clots that were densely distributed in the supracallosal cistern. Cerebral angiography demonstrated that the left pericallosal artery supplied blood flow to the bilateral parietal lobes through the bihemispheric arteries. A saccular aneurysm was found at their bifurcation. He underwent clipping surgery through interhemispheric approach. Postoperative course was uneventful. Special care should be taken not to occlude the bihemispheric arteries supplying to the bilateral parietal lobes during surgery.

Aneurysm, Ruptured↗

PubMed2005

[Vascular reconstructive surgery for elderly patients with internal carotid artery stenosis at the cervical portion].

PURPOSE: We encounted increasing numbers of elderly patients suffering from stenotic lesions of the cervical internal carotid artery. Most of them have been considered to indicate a need for carotid artery stenting. The purpose of this study was to clarify with regard to the modality of treatment and perioperative complications the effectiveness of vascular reconstruction procedure in elderly patients. PATIENTS AND METHODS: Ninety eight lesions in 91 patients with stenosis of the internal carotid artery were treated surgically. Eighty lesions received carotid endarterectomy (CEA), and 18 lesions received percutaneous transluminal angioplasty (PTA) with or without stent. Treatment with PTA-with-or-without-stent has been opted in cases of patient with such conditions as radiation-induced stenosis, re-stenosis after CEA, unfitness for general anesthesia, bilateral lesions both of which need to be reconstructed with in a short interval. We divided the patients into 4 groups according to their age; under 70-year-old group, 70-to-74-year old group, 75-to-79-year old group, and over 80-year-old group. Vasoreconstructive procedures were performed for 41 patients in the under 70-year-old group, for 31 in the 70-to-74-year old group, for 21 in the 75-to-79-year old group, and for 5 in the over 80-year-old group. RESULT: The overall surgical morbidity rate was 2% (2 of 98 cases) and there was no mortality. Tweleve patients (12.2%) experienced transient neurological deficits. Two patients exhibited perioperative complications in gastrointestinal organs, but none of the patients experienced cardiac complications. Elderly patients tend to experience systemic complications such as gastrointestinal complications as well as transient neurological deficits, which appear as restlessness, possibly due to hyperperfusion syndrome. The perioperative complication rate in elderly patients (putting the patients of the 70-to-74-year old group, the 75-to-79-year old group, and the over 80-year-old group together) was, statistically, significantly higher than those in patients of under the 70-year-old group. However, when two treatment modalities, CEA and PTA-with-or-without stent, were compared, there was no significant difference in the perioperative complication rate. CONCLUSION: Careful patient selection and prudent perioperative management enabled us to perform vasoreconstructive surgery even for elderly patients with internal carotid artery stenosis in a relatively safe manner with an acceptable complication rate. Decision making in selecting treatment modality, CEA or PTA with or without stent, should not be based solely on aging.

Age Factors↗

PubMed2004

Neuroprotective effects of the free radical scavenger Edaravone (MCI-186) in mice permanent focal brain ischemia.

The present study was aimed to evaluate the effect of the free radical scavenger Edaravone on infarct volume due to permanent MCA occlusion in mice and, if so, to elucidate the mechanism of its neuroprotective effects. Male Balb/c mice were subjected to permanent middle cerebral artery occlusion and were treated with 3.0 mg/kg of Edaravone or vehicle 30 min before ischemia. Infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) method after 24 h. Furthermore, in situ detection of superoxide in the ipsilateral neocortex was carried out using the superoxide-sensitive dye dihydroethidium (DHE) staining technique. Pretreatment with 3.0 mg/kg of Edaravone ameliorated the tissue damage in the infarct rim and significantly reduced infarct volume to about 77% of the control (p<0.05). Semi-quantitative measurement of red fluorescence emitted from DHE revealed that the superoxide increased in the ischemic core at 1 h after the onset of ischemia and extended towards the infarct rim at 3 and 6 h, and that pretreatment with 3.0 mg/kg of Edaravone significantly inhibited the increase of superoxide in the infarct rim at 3 and 6 h (p<0.01). Double staining with DHE and monoclonal antibody against NeuN showed that the majority of the nuclei positive for DHE were also positive for NeuN. These findings suggest that Edaravone salvages the boundary zone of infarct by scavenging reactive oxygen species especially in the neurons during permanent focal cerebral ischemia.

Animals↗

PubMed2004

Increased expression of hepatocyte growth factor in cerebrospinal fluid and intracranial artery in moyamoya disease.

BACKGROUND AND PURPOSE: The etiology of moyamoya disease still remains unknown. This study was aimed to explore the role of hepatocyte growth factor (HGF), a strong inducer of angiogenesis, in development of moyamoya disease. METHODS: We studied cerebrospinal fluid (CSF) from 39 patients with moyamoya disease (24 children and 15 adults), 6 control patients with cervical spondylosis, and 7 control patients with internal carotid artery occlusion. CSF level of HGF was determined by enzyme-linked immunosorbent assay technique. We also evaluated the distribution of HGF and its cellular receptor c-Met in the carotid fork obtained from 2 patients with moyamoya disease and 2 control patients. RESULTS: CSF level of HGF was 408.2+/-201.6 pg/mL and 443.2+/-193.5 pg/mL in patients with cervical spondylosis and internal carotid artery occlusion, respectively (mean+/-SD). On the other hand, CSF level of HGF was 820.3+/-319.0 pg/mL in patients with moyamoya disease, being significantly higher than those in 2 control groups (P<0.01). Both HGF and c-Met were widely distributed in the media and thickened intima of the carotid fork in patients with moyamoya disease but not in control patients. CONCLUSIONS: This study revealed that HGF is densely found in the carotid fork, and its CSF level is markedly elevated in moyamoya disease, suggesting that HGF may be a key protein for pathogenesis of moyamoya disease.

Adolescent↗

PubMed2004

Stereotactic irradiation for intracranial arteriovenous malformation using stereotactic radiosurgery or hypofractionated stereotactic radiotherapy.

PURPOSE: To investigate the appropriateness of the treatment policy of stereotactic irradiation using both hypofractionated stereotactic radiotherapy (HSRT) and stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) located in an eloquent region or for large AVMs and using SRS alone for the other AVMs. METHODS AND MATERIALS: Included in this study were 75 AVMs in 72 patients, with a mean follow-up of 52 months. Of the 75 AVMs, 33 were located in eloquent regions or were >2.5 cm in maximal diameter and were given 25-35 Gy (mean, 32.4 Gy) in four daily fractions at a single isocenter if the patient agreed to prolonged wearing of the stereotactic frame for 5 days. The other 42 AVMs were treated with SRS at a dose of 15-25 Gy (mean, 24.1 Gy) at the isocenter. The 75 AVMs were classified according to the Spetzler-Martin grading system; 21, 23, 28, 2, and 1 AVM were Grade I, II, III, IV, V, and VI, respectively. RESULTS: The overall actuarial rate of obliteration was 43% (95% confidence interval [CI], 30-56%) at 3 years, 72% (95% CI, 58-86%) at 5 years, and 78% (95% CI, 63-93%) at 6 years. The actuarial obliteration rate at 5 years was 79% for the 42 AVMs <2.0 cm and 66% for the 33 AVMs >2 cm. The 5- and 6-year actuarial obliteration rate was 61% (95% CI, 39-83%) and 71% (95% CI, 47-95%), respectively, after HSRT and 81% (95% CI, 66-96%) and 81% (95% CI, 66-96%), respectively, after SRS; the difference was not statistically significant. Radiation-induced necrosis was observed in 4 subjects in the SRS group and 1 subject in the HSRT group. Cyst formation occurred in 3 patients in the SRS group and no patient in the HSRT group. A permanent symptomatic complication was observed in 3 cases (4.2%), and 1 of the 3 was fatal. All 3 patients were in the SRS group. The annual intracranial hemorrhage rate was 5.5-5.6% for all patients. CONCLUSION: Our treatment policy using SRS and HSRT was as effective as the policy involving SRS alone. The HSRT schedule was suggested to have a lower frequency of radiation necrosis and cyst formation than the high-dose SRS schedule. The benefit of HSRT compared with lower dose SRS has not yet been determined.

Adolescent↗

PubMed2004

Sequence analysis and bioinformatics analysis of chromosome 17q25 in familial moyamoya disease.

OBJECTS: The pathogenesis of moyamoya disease is still unknown. The present study aimed to find out the responsible genes that are located in the 17q25 locus. METHODS: Considering the function, we selected nine genes as candidates from a total of 65 genes identified in the 9-cM region of D17S785-D17S836 in chromosome 17q25, and performed sequence analysis on the DNA samples obtained from a pedigree of familial moyamoya disease, which showed a complete linkage to the region by a haplotype analysis. Also, we attempted to identify candidate genes that have not been known but might be functionally relevant to the disease among a total of 2,100 expressed sequence tag (EST) sequences using bioinformatics techniques. RESULTS AND CONCLUSION: The sequence analysis could detect no mutation in the nine genes. Nor could we identify a novel candidate gene by the EST analysis. Further studies using alternative approaches are warranted to clarify the pathogenesis of moyamoya disease.

Chromosomes, Human, Pair 17↗

PubMed2004

Determinants of intellectual outcome after surgical revascularization in pediatric moyamoya disease: a multivariate analysis.

OBJECTS: The aim of this study was to clarify predictors for poor intellectual outcome in pediatric moyamoya disease. METHODS: Fifty-two pediatric patients were included. Clinical diagnosis was transient ischemic attacks (TIA) in 35 and completed stroke in 17. Ten patients underwent indirect synangiosis through "small craniotomy," whereas the other 42 underwent superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis and indirect synangiosis through "large craniotomy." Full-scale IQ (FSIQ) was measured using the Wechsler intelligence scale for children (WISC) after surgery. Multivariate logistic regression models were applied to test the effect of clinical factors on intellectual outcome. RESULTS AND CONCLUSION: Eight patients revealed mentally impaired status (FSIQ<70). Multivariate analysis revealed that completed stroke and "small craniotomy" surgery were significantly associated with poor intellectual outcome. Odds ratios of each factor were 33.4 (95% CI, 2.4-474) and 19.6 (95% CI, 1.8-215) respectively. Early diagnosis and the revascularization procedure over as wide an area as possible may be essential to improve their intellectual outcome.

Cerebral Revascularization↗

PubMed2004

FK506 reduces infarct volume due to permanent focal cerebral ischemia by maintaining BAD turnover and inhibiting cytochrome c release.

It has been reported that immunosuppressant FK506 inhibited ischemic neuronal injury in forebrain ischemia or transient focal cerebral ischemia, but the mechanisms of the neuroprotective effect have not been clarified. In permanent focal cerebral ischemia, we investigated whether FK506 caused remission of brain infarction, and how mechanism was concerned. Male Balb/c mice were subjected to permanent middle cerebral artery (MCA) occlusion. They were treated with 1.0 or 3.0 mg/kg FK506 or vehicle 30 min before ischemia. Infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) method after 24 h. Cytochrome c release from mitochondria was evaluated by Western blotting and immunocytochemistry after ischemia. Simultaneously, the immunoreactivity of total and phosphorylated BAD was also studied using immunocytochemistry. We demonstrated that pretreatment with 3.0 mg/kg FK506 salvaged the tissue damage in the infarct rim and significantly reduced infarct volume to 75.5% (P<0.05), and FK506 inhibited cytochrome c release on 6 h after ischemia for Western blot analysis (P<0.05). Immunocytochemical study showed that permanent MCA occlusion increased the amount of cytochrome c and total BAD in the cytosol, but not phosphorylated BAD, in the ischemic core and the infarct rim as early as 1 h after ischemia, and FK506 inhibited the increases in the infarct rim. The results suggest that FK506 may, at least in part, ameliorate tissue damage due to permanent focal cerebral ischemia in the infarct rim through maintaining BAD turnover and inhibiting cytochrome c release from mitochondria.

Analysis of Variance↗

PubMed2004

How does angiogenesis develop in pediatric moyamoya disease after surgery? A prospective study with MR angiography.

OBJECT: The dynamic process of neovascularization seen in patients with moyamoya disease who have received bypass surgery has not been sufficiently elucidated. Magnetic resonance angiography (MRA)is expected to disclose this process since it can be conducted frequently because of its non-invasive nature. In this study, we prospectively investigated postoperative neovascularization using repeated MRA. METHODS: We studied 14 pediatric patients (23 sides) who have received both direct bypass surgery of the superficial temporal artery (STA) to middle cerebral artery and indirect surgery of encephalo-duro-arterio-myo-synangiosis during the past 3 years. MRA was performed using a 1.5-T machine, image sequences of 512 x 256 resolution, and the time-of-flight method. MRA was prospectively performed preoperatively and repeated 1, 3, and 6 months after surgery. CONCLUSIONS: A tendency toward a decrease in moyamoya vessels and the development of the STA was observed 1 month after the surgery. Development of the deep temporal artery and the middle meningeal artery was observed 3 months after the surgery. The progression of stenotic change was apparently accelerated after the surgery. A reciprocal relation between neovascularization artificially induced by bypass surgery and moyamoya vessels, which are supposed to compensate for the stenotic change of the internal carotid artery, was disclosed.

Cerebral Revascularization↗

PubMed2004

In vivo tracking of bone marrow stromal cells transplanted into mice cerebral infarct by fluorescence optical imaging.

Recent experimental studies have indicated that bone marrow stromal cells (BMSC) improve neurological deficits when transplanted into the animal models of various neurological disorders, although precise mechanism still remains unclear. In this study, we developed a new in vivo fluorescence optical imaging protocol to sequentially track the transplanted into the brain of the living animals subjected to cerebral infarct. Mice BMSC were harvested from transgenic mice expressing green fluorescent protein (BMSC-GFP). They were stereotactically transplanted into the ipsilateral striatum of mice subjected to permanent middle cerebral artery occlusion after 7 days of ischemia (n=12). During 12 weeks after transplantation, the skull was exposed and the green fluorescence emitted from the brain surface was sequentially observed, using in vivo fluorescence optical microscopy. As the results, regional green fluorescence was detected in the ipsilateral parietal region 4-12 weeks after transplantation in all animals and became more apparent over the time. The images obtained through the skull were very similar to those acquired by thinning or removing the skull. Immunohistochemistry evaluation revealed that the transplanted cells migrated towards the ischemic boundary zone and expressed the neuronal or astrocytic marker, supporting the findings on fluorescence optical images. Sequential visualization of the BMSC transplanted into the brain of living animals would be valuable for monitoring the migration, growth and differentiation of the transplanted cells to explore the fate and safety of stem cell transplantation for various neurological disorders.

Animals↗

PubMed2004

A pre-clinical assessment model of rat autogeneic bone marrow stromal cell transplantation into the central nervous system.

In order to verify the biological aspects of 'autogeneic' bone marrow stromal cells (BMSC) transplantation for neurological disorders, we aimed our study towards the assessment of the survival, distribution, and differentiation of autologous BMSC in the central nervous system (CNS). We harvested rat BMSC from femur bones, and the nuclei were then fluorescently labeled by a 24-h co-culture with bis-benzimide. These BMSC were stereotactically injected into the striatum (n=6) or thoracic cord (n=8) of each animal. We evaluated the distribution and differentiation of 'autogeneic' BMSC in the brain and spinal cord after 4 weeks, using the immunohistochemistry technique. We found some injected cells in the ipsilateral striatum, hippocampus, neocortex, and bilateral corpus callosum, and approximately 20% and 15% of the engrafted cells expressed neuronal and astrocytic markers, respectively. Other injected cells were distributed in the dorsal funiculus and adjacent gray matter, and about 10% and 15% of these cells expressed neuronal and astrocytic markers, respectively. Although the precise mechanism of BMSC transdifferentiation still remains unclear, the present results show that 'autogeneic' BMSC could highly differentiate into their own CNS neural cells, suggesting that they are surrounded by favorable conditions.

Animals↗

PubMed2004

Co-expression of an ethylene receptor gene, ERS1, and ethylene signaling regulator gene, CTR1, in Delphinium during abscission of florets.

We are trying to determine the mechanisms responsible for ethylene-induced floret abscission in cut flowers of Delphinium and recently identified an ethylene receptor gene, ERS1, and studied its response to ethylene treatment. In order to identify additional components of the ethylene response network in Delphinium, we performed 3' and 5' rapid amplification of cDNA ends (RACE) using the consensus sequence of the serine/threonine kinase domain of the ethylene signaling regulator gene (CTR1) involved in the constitutive triple response (CTR) to ethylene. The full-length cDNA (2754 nt) encoded a protein of 800 amino acids, which contained the expected serine/threonine kinase domain, the consensus ATP-binding site, and the serine/threonine kinase catalytic site. The protein had quite high (>50%) overall identity to CTR1 from Arabidopsis and tomato, and 70-75% identity in the catalytic site. The amount of mRNA encoding both CTR1 and ERS1 more than doubled within 6 h in cut florets incubated in the presence of exogenous ethylene. Similarly, the amount of ERS1 transcript doubled in florets within 6 d of harvesting, presumably in response to endogenous ethylene, while CTR1 mRNA increased to about 40% over the same period. However, in the presence of silver thiosulfate (STS), an ethylene inhibitor, the level of both transcripts remained essentially unchanged for the first 8 d before declining to very low levels. Florets on the control plants had almost completely abscised by 6 d, but the florets on STS-treated plants had not abscised by 20 d, by which time the flowers were almost dead. The data are consistent with the hypothesis that endogenous ethylene evokes the accumulation of both these transcripts (and their encoded proteins), thereby speeding up abscission and reducing the useful shelf life of the cut flowers.

Amino Acid Sequence↗