PURPOSE: This paper is an update of previously published data on the basis of a retrospective review of midterm results of ethanol sclerotherapy on 87 patients (January 1995 to December 2000) for assessment of its efficacy as an improved treatment method for venous malformation (VM). According to this assessment, VMs were defined with a new classification and studied with advanced diagnostic technology and an advanced care system. METHODS: The average follow-up period was 24 months after completion of a multisession treatment (mean, 8.2 months). Classification of VM was based on a modification of the Hamburg classification. Advanced diagnostic technology, mostly noninvasive, was used on 226 of 520 patients with congenital vascular malformation registered at the Congenital Vascular Malformation Clinic at the Samsung Medical Center. Of the 226 patients with VM, 87 with infiltrating extratruncular lesions had a total of 399 sessions of sclerotherapy. Follow-up assessment with periodic clinical examinations by the multidisciplinary team was supplemented with body blood pool scans, duplex scans, and magnetic resonance imaging, according to protocol, once the multisession therapy was completed. Angiographic assessment was seldom included. The endpoint of this phase II study was 24 months. RESULTS: Of 399 sessions, initial success was seen in 379 sessions (95.0%) and failure was seen in 20 sessions (5%). This was mostly caused by forced abandonment from technical difficulty in delivering ethanol safely to the lesion (eg, direct drainage of VM into normal deep vein system). Later results after completion of the multisession therapy with a minimum follow-up of 24 months on 71 VMs have shown no evidence of recurrence. Eighty-seven patients have shown the same results without recurrence on an average of 18.2 months of follow-up. Fifty-one minor to major complications, mostly skin damage, developed after 47 sessions among the 379 sessions (12.4% in 24/87 patients; 27.9%). However, complications resolved spontaneously or were managed successfully, except for one permanent facial nerve palsy and one peroneal nerve palsy. CONCLUSION: Absolute ethanol sclerotherapy can deliver excellent results as an independent therapy to the infiltrating type of extratruncular form of VM, which was once taboo because of prohibitively high morbidity. Absolute ethanol may be accepted as an effective treatment method because no recurrence has been observed in the relatively long-term observation period and the morbidity has been acceptable. However, it should be reserved only for individuals and centers with expertise. The morbidity involved should be clearly understood and accepted by the patient or family, and the risk of acute and chronic complications, both major or minor, should be explained to the patient. Long-term assessment of the complication's sequelae is warranted.

Adolescent↗

PubMed2002

Processing of natural temporal stimuli by macaque retinal ganglion cells.

This study quantifies the performance of primate retinal ganglion cells in response to natural stimuli. Stimuli were confined to the temporal and chromatic domains and were derived from two contrasting environments, one typically northern European and the other a flower show. The performance of the cells was evaluated by investigating variability of cell responses to repeated stimulus presentations and by comparing measured to model responses. Both analyses yielded a quantity called the coherence rate (in bits per second), which is related to the information rate. Magnocellular (MC) cells yielded coherence rates of up to 100 bits/sec, rates of parvocellular (PC) cells were much lower, and short wavelength (S)-cone-driven ganglion cells yielded intermediate rates. The modeling approach showed that for MC cells, coherence rates were generated almost exclusively by the luminance content of the stimulus. Coherence rates of PC cells were also dominated by achromatic content. This is a consequence of the stimulus structure; luminance varied much more in the natural environment than chromaticity. Only approximately one-sixth of the coherence rate of the PC cells derived from chromatic content, and it was dominated by frequencies below 10 Hz. S-cone-driven ganglion cells also yielded coherence rates dominated by low frequencies. Below 2-3 Hz, PC cell signals contained more power than those of MC cells. Response variation between individual ganglion cells of a particular class was analyzed by constructing generic cells, the properties of which may be relevant for performance higher in the visual system. The approach used here helps define retinal modules useful for studies of higher visual processing of natural stimuli.

Action Potentials↗

PubMed2002

Effect of electroacupuncture on response to immobilization stress.

Forced immobilization is a simple and effective stressor which produces large increases in heart rate (HR), blood pressure (BP), and plasma levels of norepinephrine (NE) and epinephrine (EPI). This study investigated the effects of electroacupuncture on BP, HR, and plasma catecholamine levels in rats challenged with immobilization stress. Male Sprague-Dawley rats received electroacupuncture (3 Hz, 0.2 ms pulses, 20 mA) for 30 min after start of immobilization stress (180 min). Needlepoints corresponded to Shaohai (HT3) and Neiguan (PC6) on the heart and pericardium channel. BP and HR were monitored with an indwelling carotid catheter, and blood samples were taken from the jugular vein. Blood (for HPLC determination of NE and EPI), mean BP, and HR were sampled at rest and during the immobilization stress at 15, 30, 60, 90, 120, 150, and 180 min. Electroacupuncture at HT3 and PC6 points but not at control points (TE5, LI11, and tail) significantly reduced the expected increases in BP, HR, and attenuated plasma levels of NE and EPI in response to 3 h of immobilization stress. Results provide strong evidence that electroacupuncture effectively reduces BP and HR increases and plasma catecholamine increases in rats challenged with immobilization stress.

Animals↗

PubMed2002

Congenital vascular malformations: when and how to treat them.

Congenital vascular malformations may involve arterial, venous, and lymphatic structures, can present in a variety of forms, and present many diagnostic and therapeutic challenges. Two-thirds of all congenital vascular malformations are predominantly venous, and their management will be emphasized in this article, because of the focus of this issue. The majority of the venous malformations are asymptomatic and should be treated conservatively. However, the clinical presentation of venous malformations associated with lymphatic anomalies is variable, and management may be more challenging. The diagnosis and management of arteriovenous malformations is straightforward. Selective catheter-directed embolization of the feeding arteries, occasionally followed by tumor excision, is the treatment of choice. Hemangiomas often will grow rapidly and then begin to regress. When they produce troublesome symptoms and are well localized, they should be excised. Deeply seated or diffuse malformations require a complete diagnostic evaluation to select the most appropriate time and type of intervention. Both our own experience and that of others can provided some basis for therapeutic recommendations in treating the different vascular malformations.

Age Factors↗

PubMed2002

Randomized, double-blind comparison of different inspired oxygen fractions during general anaesthesia for Caesarean section.

BACKGROUND: The optimal inspired oxygen fraction FI(O(2)) for fetal oxygenation during general anaesthesia for Caesarean section is not known. METHODS: We randomized patients having elective Caesarean section to receive one of the following: FI(O(2)) 0.3, FI(N(2))(O) 0.7 and end-tidal sevoflurane 0.6% (Group 30, n=20); FI(O(2)) 0.5, FI(N(2))(O) 0.5 and end-tidal sevoflurane 1.0% (Group 50, n=20), or FI(O(2)) 1.0 and end-tidal sevoflurane 2.0% (Group 100, n=20) until delivery. Neonatal outcome was compared biochemically and clinically. RESULTS: At delivery, for umbilical venous blood, mean PO(2) was greater in Group 100 (7.6 (SD 3.7) kPa) compared with both Group 30 (4.0 (1.1) kPa, P<0.0001) and Group 50 (4.7 (0.9) kPa, P=0.002) and oxygen content was greater in Group 100 (17.2 (1.6) ml dl(-1)) compared with both Group 30 (12.8 (3.6) ml dl(-1), P=0.0001) and Group 50 (13.8 (2.6) ml dl(-1), P=0.0001). For umbilical arterial blood, PO(2) was greater in Group 100 (3.2 (0.4) kPa) compared with Group 30 (2.4 (0.7) kPa, P=0.003), and in Group 50 (2.9 (0.8) kPa) compared with Group 30 (2.4 (0.7) kPa, P=0.04); oxygen content was greater in Group 100 (10.8 (3.5) ml dl(-1)) than in Group 30 (7.0 (3.0) ml dl(-1), P<0.01). Apgar scores, neonatal neurologic and adaptive capacity scores, and maternal arterial plasma concentrations of epinephrine and norepinephrine before induction and at delivery were similar among groups. No patient reported intraoperative awareness. CONCLUSIONS: Use of FI(O(2)) 1.0 during general anaesthesia for elective Caesarean section increased fetal oxygenation.

Adult↗

PubMed2002

Advanced management of congenital vascular malformations (CVM).

INTRODUCTION: Congenital vascular malformations (CVM) still remain one of the most difficult diagnostic and therapeutic enigmas in modern medicine due to its extremely variable clinical presentation ranging from asymptomatic birthmarks to life threatening conditions. Extreme rarity also made it quite difficult for the clinician to make a proper diagnosis and institute optimum treatment. Poor understanding of the nature of the disease and subsequent ill-planned cavalier approach mostly by the surgeon alone only resulted in often disastrous outcomes due to prohibitively high complication and recurrence. Recently more logical attitude with multidisciplinary approach based on Hamburg classification achieved better understanding of the anatomy and pathophysiology and also advanced medical technology was able to provide the improved management in general. CLINICAL ASSESSMENT: The diagnosis itself is now feasible mostly with various combination of basic laboratory tests of non- to less- invasive nature. Selective invasive study now can be reserved as road map for the treatment in general. CLINICAL MANAGEMENT: Treatment strategy has to be set up separately for the "primary malformation" itself first from their "secondary disorders" along the vascular system and/or skeleton and soft tissue. In addition to various absolute indications of the treatment, the relative indication includes various conditions to affect the quality of life significantly besides the lesions with potentially high risk of complication, vascular-bone syndrome and cosmetically severe deformity. Various combinations of the embolo/sclerotherapy with conventional surgical therapy is implemented properly to each different malformation: absolute ethanol sclerotherapy to the venous malformation, absolute ethanol and/or N-butyl cyanoacrylate and/or coil, etc. to the AV malformation, and OK-432 to lymphatic malformation, as major embolo/scleroagents. Surgical therapy as part of total care management of CVM on the basis of multidisciplinary approach has been fully integrated to the embolo/sclerotherapy and active incorporation of the preoperative and/or postoperative embolo/sclerotherapy provides substantial improvement on the overall results of the therapy. Non- to poor surgical candidate should be considered for embolo/sclerotherapy as the primary mode of therapy. Extreme lesion with completely non-functional status of the limb should be considered for the early amputation and subsequent proper rehabilitation, instead of continuation of the aimless embolo/sclerotherapies. CONCLUSIONS: Multidisciplinary approach to congenital vascular malformations allows proper diagnosis and optimum treatment with selective combination of wide variety of therapy strategy by the integration of embolo/sclerotherapy and surgical therapy providing excellent results of the treatment even in case of complex lesions.

Humans↗

PubMed2001

Chromatic sensitivity of ganglion cells in the peripheral primate retina.

Visual abilities change over the visual field. For example, our ability to detect movement is better in peripheral vision than in foveal vision, but colour discrimination is markedly worse. The deterioration of colour vision has been attributed to reduced colour specificity in cells of the midget, parvocellular (PC) visual pathway in the peripheral retina. We have measured the colour specificity (red-green chromatic modulation sensitivity) of PC cells at eccentricities between 20 and 50 degrees in the macaque retina. Here we show that most peripheral PC cells have red-green modulation sensitivity close to that of foveal PC cells. This result is incompatible with the view that PC pathway cells in peripheral retina make indiscriminate connections ('random wiring') with retinal circuits devoted to different spectral types of cone photoreceptors. We show that selective cone connections can be maintained by dendritic field anisotropy, consistent with the morphology of PC cell dendritic fields in peripheral retina. Our results also imply that postretinal mechanisms contribute to the psychophysically demonstrated deterioration of colour discrimination in the peripheral visual field.

Animals↗

PubMed2001

Characterization and use of a digital light projector for vision research.

For creating stimuli in the laboratory, digital light projection (DLP) technology has the potential to overcome the low output luminance, lack of pixel independence, and limited chromaticity gamut of the cathode ray tube (CRT). We built a DLP-based stimulator for projecting patterns on the in vitro primate retina. The DLP produces high light levels and has good contrast. Spatial performance was similar to that of a CRT. Temporal performance was limited by the refresh rate (63 Hz). The chromatic gamut was modestly larger than that of a CRT although the primary spectra varied to a small degree with light output and numerical aperture.

Analog-Digital Conversion↗

PubMed2001

New experiences with absolute ethanol sclerotherapy in the management of a complex form of congenital venous malformation.

BACKGROUND: Complex forms of congenital venous malformation have defied proper classification and confounded therapy. Through a newly designed multidisciplinary approach, these venous defects were properly diagnosed and classified according to the Hamburg classification. Absolute ethanol was adopted as a new scleroagent for this complex form of venous defects to improve overall treatment results with acceptable morbidity and recurrence rates. PATIENTS AND METHODS: Among 318 patients aged 2 months to 60 years (130 men: mean age, 24.6 years; 188 women: mean age, 24.5 years), 143 patients were confirmed as having venous defects predominantly (45%). We conducted diagnostic evaluation with magnetic resonance imaging, whole body blood pool scan, duplex scans, transarterial microalbumin lung scans, air plethysmography, bone x-ray film, and angiography. Thirty of 143 patients were indicated for the absolute ethanol sclerotherapy for the complex form of venous defects, and they completed 98 sessions of multistage therapy with direct puncture technique. Follow-up assessment (minimum, 6 months; average, 10.2 months) was made as early results after completion of therapy. RESULTS: The immediate success rate at the completion of treatment through 98 sessions on 30 patients was 92% (90/98). The reason for the failure of 8% (8/98 sessions) was mainly due to the lesion's inaccessibility to the nidus to deliver the alcohol safely. On follow-up assessment available on 28 of 30 patients, overall improvement of the lesions with good to fair response on clinical assessment was obtained in 27 (96%) of 28 patients. Similar good to fair responses were obtained on whole body blood pool scan assessment (14 [93%] of 15 patients) and also on magnetic resonance imaging assessment (12 [93%] of 13 patients). Various major to minor acute complications developed during the procedure in eight (26.7%) of 30 patients through 16 (16.3%) of 98 sessions of the therapy: ischemic bullae, tissue fibrosis, deep venous thrombosis, pulmonary embolism, peripheral nerve palsy, and temporary pulmonary hypertension. All 24 incidences of complication were successfully managed with full recovery except one case of permanent peroneal nerve palsy that was present during 18 months of follow-up. No single recurrence has been detected to date. CONCLUSION: Absolute ethanol sclerotherapy alone can deliver excellent results in complex forms of venous malformations with considerable but acceptable morbidity and may be able to reduce the morbidity involved with the conventional surgical therapy alone on complex forms of venous malformation. No recurrence or deterioration of the therapy results was observed during the follow-up period (average, 10.2 months) after the completion of multistaged therapy.

Adolescent↗

PubMed2001

Randomized controlled study of colloid preload before spinal anaesthesia for caesarean section.

We randomized women having elective Caesarean section to receive either no preload (control group, n=33) or 4% gelatin solution (Gelofusine) 15 ml kg(-1) (colloid group, n=35) i.v. before spinal anaesthesia. Intravenous metaraminol was titrated at 0.25-0.75 mg min(-1) to maintain systolic arterial pressure (SAP) in the target range 90-100% of baseline after the spinal injection. The control group required more vasopressor in the first 10 min [median 1.7 (range 0-2.9) mg vs 1.4 (0-2.8), P=0.02] at a greater maximum infusion rate [0.5 (0-0.75) vs 0.25 (0-0.5) mg min(-1), P=0.0005] and had a lower minimum SAP [90 (51-109) vs 101 (75-127) mm Hg, P=0.006] than the colloid group. Nausea was less frequent in the colloid group (6 vs 24%) but neonatal outcome was similar in the two groups. Colloid preload improved haemodynamic stability but did not affect neonatal outcome when arterial pressure was maintained with an infusion of metaraminol during spinal anaesthesia for Caesarean section.

Adult↗

PubMed2001

The limitations of ropivacaine with epinephrine as an epidural test dose in parturients.

Explore the source record for details and available documents.

Adult↗

PubMed2001

Metaraminol infusion for maintenance of arterial blood pressure during spinal anesthesia for cesarean delivery: the effect of a crystalloid bolus.

We randomly allocated women having elective cesarean delivery to receive either no bolus (Control Group, n = 31) or 20 mL/kg lactated Ringer's solution (Bolus Group, n = 35) IV before spinal anesthesia. An infusion of metaraminol started at 0.25 mg/min was titrated to maintain systolic arterial blood pressure in the target range 90%-100% of baseline. The total dose of metaraminol required up to the time of uterine incision was similar between the Control Group and the Bolus Group (3.62 +/- 1.20 vs 3.27 +/- 1.39 mg, P = 0.3). However, the Control Group required more metaraminol in the first 5 min (1.29 +/- 0.60 vs 0.96 +/- 0.58 mg, P = 0.025) and a faster maximum infusion rate (0.45 +/- 0.20 vs 0.32 +/- 0.13 mg/min, P = 0.002) compared with the Bolus Group. There was no difference between groups in regards to changes in systolic arterial blood pressure or heart rate over time, or maternal or neonatal outcome. We conclude that when metaraminol is used to maintain arterial pressure during spinal anesthesia for cesarean delivery, crystalloid bolus is not essential provided that sufficient vasopressor is given in the immediate postspinal period.

Adult↗

PubMed2001

Dose-response study of epidural ropivacaine for labor analgesia.

BACKGROUND: Ropivacaine has been introduced for use in epidural analgesia in labor. However, there have been few formal dose-response studies of ropivacaine in this setting. METHODS: The authors performed a prospective, randomized, double-blind study examining the effectiveness of five different doses of ropivacaine (10, 20, 30, 40, and 50 mg) administered epidurally in a volume of 10 ml to establish analgesia in 66 parturients who were in active labor with cervical dilatation less than 4 cm. A dose was considered effective when the visual analog scale pain score decreased by 50% or more from baseline. RESULTS: A sigmoid dose-response curve and a probit log dose-response plot (linear regression coefficient, r = 0.84; coefficient of determination, r2 = 0.71) were obtained. The ED50 (median effective dose) obtained based on the maximum likelihood estimation was 18.4 mg (95% confidence interval, 13.4-25.4 mg). Time to onset of analgesia, duration of analgesia, time to two-segment regression of sensory block level, and incidence of motor block were not affected by the dosage of ropivacaine administered (P = 0.93, 0.12, 0.55, and 0.39, respectively). However, the upper level of sensory block was dose-related (P < 0.01). CONCLUSION: In a traditional dose-response study, the ED50 of ropivacaine required to initiate epidural analgesia in early labor was found to be 18.4 mg (95% confidence interval, 13.4-25.4 mg).

Adult↗