The necessity of routine screening for deep vein thrombosis before surgery

Background

Pulmonary embolism (PE) from deep venous thrombosis (DVT) can be a fatal postoperative complication. Preventive measures for venous thromboembolism (VTE) was evaluated in this hospital.

Materials and methods

Preoperative DVT screening following surgery under general anesthesia in 2009–2016 was examined, and then, 217 patients diagnosed with DVT by preoperative leg-ultrasound (US) between 2014 and 2016 were retrospectively analyzed.

Results

There were 24,826 operations under general anesthesia in the study period. Preoperative leg-US was performed in 5345 (21.5%) patients, and 648 (12.1% of patients, 2.6% of total operations) were diagnosed with DVT. In 2014–2016, 217 patients, which is 11.7% of patients undergoing leg-US, were diagnosed with DVT. DVT was found in the proximal veins (upper popliteal vein) in 86 (39.6%) patients. A total of 143 (62%) patients were considered to have organized thrombi, no patient developed pulmonary embolism, and 133 (58%) patients were discharged without follow-up examination for DVT. Ninety-six patients were evaluated for changes on leg-US, with no difference in the results with and without anticoagulant use. On multivariate logistic regression analysis, anticoagulants appeared effective for non-organized thrombi, higher D-dimer levels (≥10 μg/mL), or orthopedic surgery.

Conclusion

Preoperative screening for DVT did not appear useful, and treatment of asymptomatic DVT was not always necessary.

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Preoperative screening of leg-ultrasound diagnosed 12% of patients with DVT.

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Developing symptomatic embolism was not associated with anticoagulant use.

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Anticoagulants were effective for non-organized thrombi, higher D-dimer levels, or orthopedic surgery.

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Preoperative screening for DVT did not appear useful.

Transperineal abdominoperineal resection in the prone jackknife position in male patients with low rectal cancer

INTRODUCTION

In male patients with low rectal cancer undergoing abdominoperineal resection (APR), successful dissection of the anterior anorectum is key to reducing the risk of circumferential resection margin involvement, intraoperative bowel perforation, and local recurrence, but it is challenging. To overcome difficulties dissecting the anterior anorectum, we present a safe and feasible procedure using a transperineal endoscopic approach during APR (TpAPR).

MATERIALS AND SURGICAL TECHNIQUE

The male patient is placed in the prone jackknife position. TpAPR precedes the procedure from an abdominal approach. We use some pelvic tissues as clear anatomical landmarks to dissect the anterior anorectum. The key steps of this procedure are shown in the video.

DISCUSSION

The identification of a clear anatomical dissection plane of the anterior anorectum is difficult because of the complex surgical anatomy of the region. Clear anatomical landmarks for dissection of the anterior anorectum are necessary for safe implementation of this procedure. Therefore, TpAPR in the prone jackknife position can be performed to obtain better visualization of each anatomical landmark at a glance.

Transanal total pelvic exenteration in the prone jackknife position for rectal cancer invading the bladder, seminal vesicles, and small intestine

A 58-year-old man had rectal cancer directly invading the urinary bladder and small intestine, without distant metastasis. We successfully performed complete resection using a hybrid approach, including laparoscopic surgery and transanal total pelvic exenteration (TaTPE) with the patient in the prone jackknife (PJK) position. In the PJK position, gravity and pelvic morphology lead to a clear and wide surgical field. This case demonstrates that total pelvic exenteration using laparoscopic surgery and TaTPE in the PJK position provides a better surgical field than either TaTPE or laparoscopic surgery in the supine position. TaTPE in the PJK position may also be useful for curative surgery in locally advanced rectal cancer.

Hybrid approach using laparoscopy and transanal minimally invasive surgery to treat rectal cancer with invasion to the seminal vesicles

We treated a 64-year-old man for rectal cancer with direct invasion to the seminal vesicles and no distant metastases by complete resection with laparoscopy and transanal minimally invasive surgery (TAMIS). We inserted the TAMIS device into the anal canal to above the anorectal ring and dissected to prostate level. High ligation of the inferior mesenteric artery and vein was performed by standard medial laparoscopy. The sigmoid and descending colon were mobilized, and in the postrectal space, we dissected to the space made by TAMIS. The membranous peritoneum was dissected on both sides of the rectum to the cul de sac. The peritoneum was dissected anterolaterally to reveal the seminal ducts, which were ligated and dissected on both sides. The seminal vesicles were dissected from the posterior wall of the bladder to the prostate level. The rectal specimen was now fully mobilized. Lower rectal resection with combined laparoscopy and TAMIS provided a better surgical plane than standard laparoscopy.

Laparoscopic radical lymph node dissection for advanced colon cancer close to the hepatic flexure

INTRODUCTION

Complete mesocolic excision is currently recognized as a standard procedure for colon cancer. Gastroepiploic, infrapyloric, and superficial pancreatic head lymph node metastases in the gastrocolic ligament have been reported for colon cancer close to the hepatic flexure. We sought to investigate metastases in the gastrocolic ligament in colon cancer close to the hepatic flexure.

METHODS

This was a single-center retrospective study. All patients with T2 or deeper invasive colon cancer in the relevant tumor location who underwent laparoscopic right hemicolectomy or extended right hemicolectomy at our institution between 1 April 2011 and 31 March 2015 were included.

RESULTS

Lymph node dissection in the gastrocolic ligament was performed in 35 cases. Complications occurred in 11 patients (31%) and were grades I and II according to the Clavien-Dindo classification. Lymph node metastases in the gastrocolic ligament were found in only three patients (9%). Each metastasis was larger than 9 mm.

CONCLUSIONS

Metastases in the gastrocolic ligament occurred in 9% of patients with T2 or deeper invasive colon cancer close to the hepatic flexure. Laparoscopy was feasible and useful during gastrocolic ligament resection. This study included a small sample and lacked an extended follow-up. Further studies are needed to determine the clinical relevance of this finding, particularly in terms of recurrence and long-term survival.

Laparoscopic Hartmann's procedure for fecal peritonitis resulting from perforation of the left-sided colon in elderly and severely ill patients

BACKGROUND

Traditional treatment for fecal peritonitis resulting from perforation of the left-sided colon has been performed using Hartmann's procedure to reduce the high mortality caused by anastomotic leakage. However, the morbidity rates associated with abdominal incision (due in great part to wound infection, and dehiscence of abdominal fascia) are high. Therefore, we propose using laparoscopic Hartmann's procedure with abdominal incisions only for the port site to reduce the high morbidity associated with the laparoscopic procedure as compared to open surgery.

METHODS

Between April 2008 and July 2011, we treated 16 consecutive patients (median age, 83 years) with fecal peritonitis resulting from perforations in the left-sided colon due to various causes. The American Society of Anesthesiologists score of each patient was either IV or V. Patients underwent a four-port laparoscopic Hartmann's procedure. Specimens were extracted through the stoma site. Irrigation of the abdominal cavity with more than 10 L of saline was performed in every case, as was insertion of three 10-mm silicon drains via the port site into the left- and right subphrenic spaces or the pouch of Douglas.

RESULTS

The median total surgical time was 166 min (range, 123-250 min). There were no intraoperative complications, and there was no need to convert to open surgery. Fourteen patients survived. There was no wound infection or dehiscence of abdominal fascia. Successful laparoscopic reversals of the laparoscopic Hartmann's procedure were performed in all 14 survivors.

CONCLUSIONS

This laparoscopic Hartmann's procedure is a promising surgical strategy for treating fecal peritonitis arising from perforation of the left-sided colon.

Single-access laparoscopic colectomy with a novel multiport device in sigmoid colectomy for colon cancer

PURPOSE

Laparoscopic-assisted colectomy is a common procedure for colorectal disease, and laparoscopic colectomy from a single access point is rapidly evolving. This report describes the use of single-access laparoscopic colectomy (SALC) with a novel multiport device in sigmoidectomy for colon cancer.

METHODS

Data were collected retrospectively on 5 patients who underwent the procedure for colon cancers in the period from November 2008 through January 2009. The abdomen was approached through a 3- to 4-cm incision via the umbilicus in every case. To ensure maintenance of the pneumoperitoneum, the procedure was performed with a specially developed multiport device enveloped by a glove containing 3 5-mm ports. In all 5 patients, the root of the inferior mesenteric artery was isolated and divided at the distal side where the left colic artery branched off.

RESULTS

The median total surgical time was 185 (range, 176-210) minutes. In all patients, surgical blood loss was slight (range, 0-20 mL). Only one patient required conversion into laparoscopic-assisted colectomy by the addition of 2 ports, because the location adjacent to the descending colon made it necessary to mobilize the splenic flexure. The median number of harvested lymph nodes was 17 (range, 12-24). No postoperative complications occurred. The postoperative hospital stay was 7 days for every patient.

CONCLUSIONS

Single-access laparoscopic sigmoidectomy seems to be feasible and safe when performed by experienced laparoscopic surgeons who are familiar with the unique principles of this procedure. Additional experience and continued investigations are warranted.

Fluorometric measurement of intracellular pH in vivo in feline cerebral cortex during ischemia and reperfusion

Intracellular acidosis has been considered to play an pivotal role in the progression of neuronal damage after cerebral ischemia. However, continuous measurement of the intracellular potential of hydrogen (pH) has not been done during and after ischemia. We measured temporal changes in intracellular pH in the feline cerebral cortex in vivo during and after ischemia using a novel fluorescent pH probe, 2',7'-biscarboxyethyl carboxyfluorescein (BCECF). A closed cranial window was installed in the left temporal skull. BCECF acetoxymethyl ester was superfused over the cortex, hydrolyzed and trapped in cortical cells. Intracellular pH was measured utilizing excitation light at 507 nm and fluorescent light at 550.5 nm. Focal cerebral ischemia for 60 minutes was induced by means of middle cerebral artery occlusion. Intracellular pH in the severely ischemic group became significantly acidic (p < 0.01) during ischemia and the acidosis persisted for at least 30 minutes after recirculation. The pH change was not significant in the mildly ischemic group. The severity of ischemia was determined based on the mean transit time, which was calculated from the hemodilution curve obtained by bolus injection of saline. The extent of ischemia was further confirmed pathologically (p < 0.01). The above results suggest that intracellular acidosis resulting from severe ischemia persists even after recirculation.

Neuroprotective effect of YM90K, a novel AMPA/kainate receptor antagonist, in focal cerebral ischemia in cats

We studied the effect of a novel alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate antagonist, YM90K [6-(1H-imidazol-1-yl)-7-nitro-2, 3(1H, 4H)-quinoxalinedione monohydrochloride], in a focal cerebral ischemia model using anesthetized cats. Cats were subjected to permanent occlusion of the middle cerebral artery (MCA) for 6 h, then killed and examined histologically. The amount of ischemic damage was assessed in 12 stereotaxic coronal sections. Treatment with YM90K (i.v. infusion of 0.5 mg/5 ml/kg/h) starting 10 min after MCA occlusion markedly reduced the volume of ischemic damage (from 2823 +/- 164 mm3 of the cerebral hemisphere in saline-treated cats to 1737 +/- 305 mm3 in YM90K-treated cats). No essential differences were observed between YM90K-and saline-treated cats concerning physiological variables or brain temperature. These results further support the notion that the AMPA/kainate receptor plays an important role in the pathogenesis of focal cerebral ischemia. This evidence for the neuroprotective efficacy of YM90K in a gyrencephalic species suggests its therapeutic potential in the treatment of human stroke.

Guillain-Barré syndrome with bilateral tonic pupils

A 53-year-old patient with Guillain-Barré syndrome preceded by herpes simplex virus infection developed bilateral tonic pupils with light-near dissociation. Pharmacological tests for pupils suggested postganglionic involvement of the parasympathetic and sympathetic nerves. A demyelinating process of peripheral autonomic nerves was suspected to be the cause of the tonic pupils and autonomic dysfunction.

The effect of hyperglycemia on intracellular calcium in stroke

The effect of hyperglycemia on cytosolic free calcium ([Ca2+]i) during temporary focal cerebral ischemia was investigated in cats using a fluorometric technique. The middle cerebral artery (MCA) was occluded for a period of 1 h, after which the clip was removed. In seven animals, plasma glucose was raised to 500-700 mg/dl by infusion of a 50% glucose solution starting 30 min after MCA occlusion, while eight animals were kept normoglycemic during and following occlusion. MCA occlusion induced a significant, but identical, elevation of the [Ca2+]i signal ratio (400/506 nm) in both the normoglycemic group (from 1.40 to 1.97 +/- 0.34, p less than 0.01) and in the hyperglycemic group (from 1.40 to 2.00 +/- 0.53, p less than 0.01) at the end of the occlusion. Between 10 and 30 min after reopening, the [Ca2+]i signal ratio decreased to control levels in the normoglycemic group (1.40 +/- 0.11 and 1.36 +/- 0.08 at 10 and 30 min after reopening, respectively), but remained elevated in the hyperglycemic group (1.69 +/- 0.18 and 1.65 +/- 0.21 at 10 and 30 min after reopening, respectively). There was a statistically significant difference between the two groups (p less than 0.01). These data suggest that hyperglycemia may be harmful to calcium recovery during the early recirculation period following focal cerebral ischemia.

Effect of superoxide dismutase on intracellular calcium in stroke

To clarify the relationship between calcium metabolism and free radical damage during the reperfusion period following ischemia, we investigated the effect of superoxide dismutase (SOD) on changes in cytosolic free calcium, cortical blood flow, and histologic changes following focal cerebral ischemia and reperfusion in 12 cats. Using indo-1, a fluorescent intracellular Ca2+ indicator, we simultaneously measured changes in the Ca2+ signal ratio (400:500 nm), NADH signal (464 nm), and reflectance (340 nm) during ultraviolet excitation (340 nm) directly from the cortex in vivo. The middle cerebral artery (MCA) was occluded for 1 h; only cats in which the EEG amplitude was depressed to less than 10% of control during the occlusion were entered into the study. Starting 2 min prior to release of the occlusion and continuing for 4 min, SOD (10,000 U/kg) was slowly infused in six cats, while in six cats, the vehicle only was infused. During MCA occlusion, the Ca2+ signal ratio increased significantly in both groups with no significant difference between the groups. During reperfusion, the Ca2+ signal ratio remained at a high level in the vehicle-treated group, while in the SOD-treated group, the Ca2+ signal ratio decreased. There was a statistically significant difference between the two groups at 10, 20, and 30 min after reperfusion (p less than 0.01). The histologically damaged area in the SOD-treated group was significantly smaller than that in the vehicle-treated group (p less than 0.01). These data suggest that the histoprotective action of SOD may be due to its ability to attenuate increases in intracellular calcium during the recirculation period following focal cerebral ischemia.

Mechanism underlying protective effect of MK-801 against NMDA-induced neuronal injury in vivo

The effects of the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 and the dihydropyridine calcium antagonist nimodipine on NMDA-induced phenomena were investigated using an in vivo fluorometric technique with indo-1. Indo-1, a fluorescent cytosolic free calcium ([Ca2+]i) indicator, was loaded into the cat cortex approximately 500 microns in depth by superfusion with the membrane-permeant indo-1 acetoxy-methyl ester (indo-1-AM). Changes in [Ca2+]i signals (400 and 506 nm) and reduced nicotinamide adenine dinucleotide (NADH) fluorescence (464 nm) were simultaneously measured directly from the cortex during ultraviolet excitation (340 nm). Superfusion of 100 microM NMDA over the exposed cortex induced an elevation of the [Ca2+]i signal ratio (400/506 nm), biphasic changes in NAD/NADH redox state (initial oxidation followed by progressive reduction), and characteristic changes in the EEG (abrupt depression in amplitude followed by an excitatory pattern of 18-22 Hz polyspikes or sharp waves). These changes were completely blocked by treatment with MK-801 and reduced by nimodipine. The mechanism underlying the protective effects of systemically administered MK-801 on the NMDA-induced neuronal injury was verified in vivo.

Intracellular calcium and pathophysiological changes in cerebral ischemia

The role of calcium as a mediator in neuronal death during ischemia is now quite strong. Evidence supporting this link included studies in cell cultures, measurements of calcium accumulation in the mitochondria during ischemia as well as direct measurements of shifts in extracellular calcium using microelectrodes. Since high concentrations of intracellular free calcium have been hypothesized to lead to neuronal damage, direct in vivo measurements of this parameter in ischemia are important. The studies outlined demonstrate that changes in intracellular free calcium occur in focal ischemia and describe the time course of these changes. They indicate that cellular damage can be attenuated by the use of agents that block calcium channels (both voltage-sensitive and receptor-operated) and support the concept that these agents owe their beneficial effects to their ability to reduce the accumulation of intracellular calcium.

Combined therapy with MK-801 and nimodipine for protection of ischemic brain damage

Calcium ion can enter ischemic neurons through both receptor-operated and voltage-sensitive Ca2+ channels. To attenuate this Ca2+ entry and Ca2(+)-induced neuronal injury, we tried a combined treatment with the noncompetitive N-methyl-D-aspartate (NMDA) antagonist, MK-801, and the dihydropyridine calcium antagonist, nimodipine, in a cat middle cerebral artery occlusion (1 hour) and reperfusion (3 hours) model. We measured changes in cytosolic free calcium, nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide redox state, and blood flow in the cat cortex using a newly developed fluorometric technique with indo-1, a fluorescent intracellular Ca2+ indicator. The combined treatment, starting 5 minutes into ischemia, was effective in reducing both Ca2+ entry and histologic damage and in enhancing recovery of the electroencephalogram following reperfusion. MK-801 alone was also effective, but to a lesser extent. These data suggest that the dual blockade of Ca2+ entry using MK-801 and nimodipine may be a useful tool for protection against ischemic brain damage.

Cytosolic free calcium during focal cerebral ischemia and the effects of nimodipine on calcium and histologic damage

The role of calcium as a mediator in neuronal death during ischemia is now quite strong. Evidence supporting this link includes studies in cell cultures and measurements of calcium accumulation in the mitochondria during ischemia, as well as direct measurements of shifts in extracellular calcium using microelectrodes. Since it is dangerously high concentrations of the intracellular free calcium that have been hypothesized to lead to neuronal damage, direct in vivo measurements of this parameter in ischemia are important. A technique for the measurement of intracellular free calcium is described, along with data from studies that dramatically demonstrate the time course of changes in intracellular free calcium induced by focal ischemia. Additional data are also presented that indicate that cellular damage can be attenuated by the use of agents that block calcium channels (nimodipine, which blocks voltage-sensitive calcium channels, and MK-801, which blocks receptor-operated channels) and support the concept that these agents owe their beneficial effects to their ability to reduce the accumulation of intracellular calcium.

Alterations in cytosolic free calcium in the cat cortex during bicuculline-induced epilepsy

Influx of calcium ion (Ca++) into the neurons has recently been implicated in the generation of seizure activity. Utilizing indo-1, a fluorescent Ca++ indicator, changes in cytosolic free calcium ([Ca++]i), NAD/NADH redox state and hemodynamics were simultaneously measured in vivo from the cat cortex during bicuculline-induced seizure activity. A ratio of indo-1-Ca++ fluorescence at 400 and 506 nm during ultraviolet excitation (340 nm) was utilized as a measure of changes in [Ca++]i. Alterations in the NAD/NADH redox state and local cortical blood volume (1CBV) were assessed at 464 nm and 340 nm, respectively. Local cortical blood flow (1CBF) was calculated from 1CBV and mean transit time determined from cortical hemodilution curves. Electroencephalogram (EEG) was monitored from the same cortical region as the optical measurements. The [Ca++]i signal ratio started to increase 19 +/- 2 sec prior to the onset of seizure activity on the EEG and remained elevated until the activity was suppressed by an intravenous administration of diazepam (2 mg/kg). The early increase in [Ca++]i is presumably due to a synaptic Ca++ entry associated with facilitated excitatory neurotransmission. The NAD/NADH redox state became oxidized during the seizure activity and started to recover as the EEG activity was suppressed. The 1CBV and 1CBF increased by 17 +/- 8% and 68 +/- 16%, respectively, 10 min into the seizure activity. This study provides direct in vivo evidence suggesting a possible role of calcium entry into the neurons in the epileptogenesis.

Nimodipine attenuates both increase in cytosolic free calcium and histologic damage following focal cerebral ischemia and reperfusion in cats

To clarify the mechanism of its effect on ischemic stroke, we investigated the effect of nimodipine, a dihydropyridine calcium antagonist, on changes in cytosolic free calcium, cortical blood flow, and histologic changes following focal cerebral ischemia and reperfusion in 14 cats. Using indo-1, a fluorescent intracellular Ca2+ indicator, we simultaneously measured changes in the Ca2+ signal ratio (400:506 nm), reduced nicotinamide adenine dinucleotide fluorescence (464 nm), and reflectance (340 nm) during an ultraviolet excitation (340 nm) directly from the cat cortex in vivo. In six cats treated with vehicle only, the calcium signal ratio increased from 5 minutes after middle cerebral artery occlusion to 30 minutes into reperfusion. The elevation of cytosolic free calcium was significantly attenuated by nimodipine, which was administered by intravenous infusion in eight cats starting 5 minutes after occlusion. Nimodipine had no effect on cortical blood flow during ischemia but induced a hyperperfused state following reperfusion. Nimodipine did not modify changes in the mitochondrial oxidation-reduction state. Nimodipine proved to have beneficial effects on recovery of the electroencephalogram following reperfusion as well as on the extent of focal histologic damage. Our results suggest that nimodipine, when administered during the early stage of focal ischemia, can favorably modify the outcome of stroke by reducing the Ca2+ entry during both the ischemic and reperfusion periods.

Direct evidence for calcium-induced ischemic and reperfusion injury

Changes in cytosolic free calcium [( Ca2+]i) in the cat cortex were measured in vivo by indo-1 fluorometry during cerebral ischemia and reperfusion and were correlated to the histopathological ischemic changes. These changes were most pronounced in stroke cases with an increase in [Ca2+]i throughout the ischemic and reperfusion periods. Cases without a [Ca2+]i increase showed no histopathological change in the cortical gyrus in which [Ca2+]i was measured. The data support the hypothesis that an increase in [Ca2+]i during cerebral ischemia and reperfusion leads to neuronal damage.

Effects of a selective inhibitor of cyclic AMP phosphodiesterase on the pial microcirculation in feline cerebral ischemia

We evaluated the effects of cilostazol, a selective inhibitor of cyclic adenosine monophosphate phosphodiesterase, on the pial vessels of adult cats subjected to endothelial damage followed by middle cerebral artery occlusion. Six cats were treated with cilostazol and four with 30% N,N-dimethylformamide in 70% saline (solvent). The brain surface was irradiated with ultraviolet rays through a cranial window for 3 minutes to selectively damage the endothelium of the pial vessels in both groups. Beginning 32 minutes after termination of the irradiation, the middle cerebral artery was occluded for 30 minutes. Thirty minutes before occlusion, intravenous infusion of 30 micrograms/kg/min cilostazol or 0.1 ml/kg/min solvent was begun and continued until the end of the study. Before occlusion, the infusion of cilostazol induced a significant (p less than 0.05) dilatation while the infusion of solvent produced no significant changes in the diameter of the pial arteries. The pial veins of solvent-treated cats showed significant (p less than 0.05) constriction during occlusion, whereas cilostazol-treated cats exhibited only mild constriction of the pial veins. The formation of platelet thrombi after occlusion was significantly (p less than 0.05) inhibited in the pial veins of cilostazol-treated compared with solvent-treated cats. Similarly, the microcirculation of the pial veins was effectively restored after reopening of the middle cerebral artery in cilostazol-treated compared with solvent-treated cats. Our data suggest that cilostazol is an effective antithrombotic agent as well as a potent vasodilator acting on vascular smooth muscle.

Cytosolic free calcium, NAD/NADH redox state and hemodynamic changes in the cat cortex during severe hypoglycemia

Using indo-1, a fluorescent Ca2+ indicator, in vivo fluorometric measurements were made of changes in cytosolic free Ca2+, NAD/NADH redox state, and hemodynamics directly from the cat cortex during and after severe insulin-induced hypoglycemia. Cytosolic free Ca2+ started to increase when the EEG became isoelectric, remained at a significantly high level (p less than 0.05) during the period of isoelectric EEG (IEEG), and recovered to the control level 6 min following an intravenous infusion of glucose. The NAD/NADH redox state oxidized significantly during IEEG and then recovered rapidly to the control level after the glucose infusion. Local cortical blood volume (LCBV) increased gradually during the progression of hypoglycemia, reaching the maximal level (146 +/- 7%) at the end of IEEG, and then started to recover. The mean transit time (MTT) through the cortical microcirculation was shortened during the IEEG (control: 3.84 +/- 0.41 s versus IEEG: 2.73 +/- 0.17 s, p less than 0.05), whereas it was prolonged during the 30-min recovery period (5.68 +/- 0.58 s, p less than 0.05). Local cortical blood flow calculated from the LCBV and MTT showed a twofold increase 5 min into IEEG (201 +/- 27% of control, p less than 0.05), recovered 15 min into the recovery period, and then decreased to 77% of control (p less than 0.05) by 30 min. The data support the hypothesis that hypoglycemic brain damage might be mediated by an elevation of cytosolic free calcium.

Cytosolic free calcium and NAD/NADH redox state in the cat cortex during in vivo activation of NMDA receptors

Activation of the N-methyl-D-aspartate (NMDA) receptors and the concomitant Ca2+ entry have been implicated in neuronal injury in a variety of pathological states. The effects of extracellular Mg2+ concentrations and D,L-2-amino-5-phosphonovaleric acid (APV), a competitive NMDA receptor antagonist on the NMDA-induced responses were investigated in vivo. In vivo fluorometric measurements were made of changes in cytosolic free Ca2+ ([Ca2+]i) and NADH fluorescence directly from the cat cortex using indo-1, a fluorescent Ca2+ indicator. Changes in [Ca2+]i were assessed utilizing the ratio of indo-1 emission at two wavelengths (400 and 506 nm) during excitation with ultraviolet light (340 nm). Application of 100 microM NMDA to the cortex produced a significant increase in the [Ca2+]i signal ratio at physiological concentrations of Mg2+ (1.2 mM). This increase was enhanced in the absence of Mg2+ and was completely blocked either at 5 mM Mg2+ or in the presence of 50 microM APV. The NAD/NADH redox state was initially oxidized, which was also blocked by either high Mg2+ or APV. The application of NMDA elicited characteristic electroencephalogram (EEG) changes consisting of a marked reduction in amplitude and regular spikes (17-20 Hz). These EEG changes did not appear in the presence of APV. In addition to NMDA receptor antagonists, the level of extracellular Mg2+ is a potent physiological modulator of the NMDA response.

Stable prostacyclin analogue preventing microcirculatory derangement in experimental cerebral ischemia in cats

We evaluated the effect of a stable synthetic prostacyclin analogue, TRK-100, on the microcirculatory derangement occurring in feline pial vessels with endothelial damage after middle cerebral artery occlusion. Fifteen adult cats were divided into an untreated group (Group 1, n = 8) and a treated group (Group 2, n = 7). Thirty minutes after 10 minutes of ultraviolet irradiation, which selectively damaged endothelium in the pial vessels, the middle cerebral artery was occluded in both groups and maintained for 30 minutes. In Group 2, 50 ng/kg/min TRK-100 was continuously infused intravenously following ultraviolet irradiation. In both the pial arteries and veins, platelet aggregate adhesion to the endothelium with subsequent thrombus formation was significantly (p less than 0.01 and p less than 0.05, respectively) inhibited during middle cerebral artery occlusion in Group 2 compared with Group 1. Similarly, blood flow stasis in the pial veins was effectively prevented in Group 2 during occlusion. Furthermore, the pial artery diameter returned to the control level during the late period of occlusion, whereas in Group 1 the pial artery remained constricted. Our data suggest that TRK-100 can prevent microcirculatory derangement in the acute stage of ischemic stroke.

In vivo measurement of cytosolic free calcium during cerebral ischemia and reperfusion

An increase in cytosolic free calcium concentration ([Ca2+]i) may trigger irreversible cell injury following cerebral ischemia. We have measured changes in [Ca2+]i in cat cortex in vivo during ischemia produced by 1 hour of middle cerebral artery occlusion and during 30 minutes of reperfusion. Indo-1, a fluorescent Ca2+ indicator, was loaded into the exposed cortex by superfusion, and changes in the [Ca2+]i signal (400/506 nm ratio) were measured microfluorometrically during ultraviolet excitation (340 nm). The nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide (NAD/NADH) redox state and hemodynamic changes were measured simultaneously. The animals showing severe deterioration in their electroencephalograms (EEG) showed a progressive increase in the [Ca2+]i signal during ischemia (baseline: 1.46 +/- 0.05; 60 minutes after occlusion: 2.99 +/- 0.37; n = 7). At 30 minutes following reperfusion, the animals showing little recovery in their EEG exhibited a further increase in [Ca2+]i (4.71 +/- 0.87, n = 3), whereas animals showing significant recovery in their EEG also showed recovery of [Ca2+]i (1.55 +/- 0.09, n = 4). By contrast, the moderate or mild stroke animals with less deterioration in their EEGs showed no increase in [Ca2+]i during either ischemia or reperfusion. These data suggest that the increase in [Ca2+]i might be closely related not only to deterioration of brain function during ischemia but also to poor recovery during the reperfusion period.

In vivo fluorometric measurement of changes in cytosolic free calcium from the cat cortex during anoxia

A new approach to assess the mean changes in intracellular free calcium [Ca2+]i directly from the cortex in situ is described along with the [Ca2+]i changes during nitrogen anoxia. Following incision of the dura and part of the pia-arachnoid membrane, quin2 acetoxymethyl ester, 100 microM in artificial CSF, was superfused for 60 min onto the cat cortex. A small cortical area was irradiated with ultraviolet rays (350/30 nm) and the changes in the fluorescence and reflectance were recorded microfluorometrically at 506 and 366 nm, respectively. The net change in the quin2-Ca2+ fluorescence was calculated after correction for the hemodynamic artifact and subtraction of the basal NADH change. The quin2-Ca2+ fluorescence began to increase significantly (48.0 +/- 13.4 units; p less than 0.05) 20 s prior to the isoelectric electrocorticogram (ECoG) and remained elevated during nitrogen anoxia. It decreased steeply 7.3 +/- 1.7 s prior to the recovery of the ECoG activity after the animal was reoxygenated. Thus, the changes in the intracellular free calcium preceded those of the ECoG during a reversible anoxic insult, suggesting that the increase in the [Ca2+]i might be related to the electrical failure during anoxia.

Comparison between pial and intraparenchymal vascular responses to sympathetic stimulation under hypercapnic conditions. With special reference to the mechanism for escape phenomenon

We have shown that secondary vasodilation ('escape' phenomenon) during sympathetic nerve stimulation occurs in the intraparenchymal vessels but not remarkable in the pial vessels. To test a possible role of CO2 accumulation in the brain tissue in this phenomenon, the responses of pial and intraparenchymal vessels to sympathetic nerve stimulation were investigated during hypercapnia in 9 cats by using a video camera photoelectric system. The ipsilateral superior cervical ganglion was electrically stimulated for 5 min during hypercapnia (PaCO2 = 50 +/- 2 mm Hg). The intraparenchymal vessels as well as pial vessels remained constricted throughout the stimulation. Secondary dilation of the intraparenchymal vessels as seen at the later stage of sympathetic stimulation during normocapnia was not observed under the hypercapnic conditions. We assume that the arterial CO2 tension was so high that the constriction of inflow vessels could not result in accumulation of CO2 in the brain parenchyma. The accumulation of chemical metabolites as represented by CO2 is therefore considered to be the most probable mechanism underlying the escape phenomenon of the intraparenchymal vessels.

Quantitative measurement of blood flow velocity in feline pial arteries during hemorrhagic hypotension and hypercapnia

Due to methodologic difficulties, few investigations have been made on the blood flow velocity in the cerebral microcirculation. Using a newly developed video camera method, we simultaneously measured the blood flow velocity and diameter of pial arteries during hemorrhagic hypotension, after blood pressure recovery, and during CO2 inhalation in cats. When the mean arterial blood pressure was lowered from 129.7 +/- 6.6 to 71.5 +/- 4.1 mm Hg, the blood flow velocity inevitably decreased from 36.6 +/- 5.3 to 27.0 +/- 3.9 mm/sec (p less than 0.001). The calculated blood flow rate [pi X (diameter/2)2 X flow velocity] was preserved in cases with concomitant vasodilation. Conversely, the blood flow velocity increased from 25.3 +/- 5.1 to 31.0 +/- 5.4 mm/sec (p less than 0.001) after mean arterial blood pressure recovery from 67.1 +/- 3.7 to 129.8 +/- 5.8 mm Hg. The blood flow rate was again preserved in vessels with a vasoconstrictive response. Each pial artery apparently dilated or constricted in proportion to the decrease or increase in flow velocity during blood pressure changes, maintaining a constant cerebral blood flow. This indicated the importance of the pial arteries in the mechanisms of cerebral blood flow autoregulation. During 5% CO2 inhalation, the blood flow velocity increased markedly from 25.4 +/- 4.6 to 37.2 +/- 10.0 mm/sec (p less than 0.05), while the pial artery diameter (85.0 +/- 13.7 microns) increased by 9.6 +/- 1.5% (p less than 0.01). The increased flow velocity might be attributable to preferential dilatation of small arterioles or intraparenchymal vessels during hypercapnia.(ABSTRACT TRUNCATED AT 250 WORDS)

Brainstem auditory evoked responses and CT findings in multiple system atrophy

Brainstem auditory evoked responses (BAERs) and CT findings were comparatively studied in 11 patients with Shy-Drager syndrome and 10 patients with olivopontocerebellar atrophy. The I-III interpeak latencies (IPLs) were prolonged in 6 patients with Shy-Drager syndrome and in 6 patients with olivopontocerebellar atrophy. Mean values of the I-III IPLs were 2.54 +/- 0.28 ms (Shy-Drager syndrome) and 2.62 +/- 0.15 ms (olivopontocerebellar atrophy). In each disease, the I-III IPLs correlated well with the degree of the pontine atrophy estimated from the CT scan. The patients with Shy-Drager syndrome could be clinically divided into two varieties. In addition to autonomic dysfunction, one variety (4 patients) was linked with parkinsonism, and the other (7 patients) with signs of multiple nervous systems involvement. Prolongation of I-III IPLs and pontine atrophy were noted in 6 out of the latters patients, whereas the former patients did not show such abnormalities. The combination of BAERs and CT scan provides useful clinical information on multiple system atrophy.

Comparison between pial and intraparenchymal vascular responses to cervical sympathetic stimulation in cats. Part 1. Under normal resting conditions

To investigate the role of sympathetic regulation in both resistance and capacitance vessels in cerebral circulation, the response of pial and intraparenchymal vessels to sympathetic nerve stimulation were simultaneously examined in 14 cats by means of a newly developed video camera photoelectric system. The system consisted of a video camera system for measurement of pial vascular diameters and a photoelectric apparatus for estimating regional cerebral blood volume in the intraparenchymal vessels. The ipsilateral superior cervical ganglion was electrically stimulated for 5 min. Initially, both the pial and intraparenchymal vessels constricted. The large pial arteries (173 +/- 25 micron, mean +/- SEM) remained constricted throughout the stimulation, whereas the intraparenchymal vessels began to dilate after the initial constriction and exceeded the control level at 175 +/- 25 s despite continued stimulation. In conclusion, such sympathetic nerve stimulation is considered to exert a constrictive effect on the intraparenchymal as well as the pial vessels at the early stage. The compensatory dilation of the intraparenchymal vessels was delayed 3 min after initiation of the stimulation.

Midbrain locked-in state with oculomotor subnucleus lesion

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Effects of (D-Met2,Pro5)-enkephalinamide and naloxone on pial vessels in cats

To elucidate the fundamental actions of endogenous opioids and naloxone on the cerebral circulation, the effects of (D-Met2,Pro5)-enkephalinamide and naloxone on pial vessels were investigated in cats. Pial arteries (165.7 +/- 24.9 microns) were found to dilate after the intravenous administration of 1 mg/kg of (D-Met2,Pro5)-enkephalinamide, and a definite dilatation of 7.1-7.6% persisted for 15 min. Pial veins (100.6 +/- 20.2 microns) also dilated but to a lesser degree. The MABP (118.7 +/- 10.5 mm Hg) decreased by 20 mm Hg immediately after the injection, but gradually returned to the initial value 15 min later. The observed cerebral vasodilatation may be attributable to sympathetic inhibition mediated either by the presynaptic opiate receptors of the cerebral vessels or by the opiate receptors in the brainstem. After the intravenous administration of 1 mg/kg of naloxone, pial arteries (122.0 +/- 17.2 microns) showed a slight but significant dilatation of 2.3-5.3%. There were no significant changes in pial veins (87.0 +/- 12.4 microns). MABP (130.4 +/- 12.3 mm Hg) was slightly increased after the injection. Although the mechanism involved was unclear, the cerebral vasodilatation occurring after the administration of naloxone may contribute to its ameliorating effect on the neurological symptoms following cerebral ischemia.

Fisher's syndrome following trigeminal herpes zoster

A case of Fisher's syndrome associated with trigeminal herpes zoster is reported for the first time. Retrograde propagation of the virus to the brainstem through the trigeminal root was thought to be the most probable pathogenic mechanism. We provide additional evidence suggesting that the focus of Fisher's syndrome is in the brainstem.

Blood flow velocity in the pial arteries of cats, with particular reference to the vessel diameter

The blood flow velocity and diameter of feline pial arteries, ranging in diameter from 20 to 200 microns, were measured simultaneously using a newly developed video camera method under steady-state conditions for all other parameters. There was a linear relationship between blood flow velocity and pial artery diameter (y = 0.340x + 0.309), the correlation coefficient being 0.785 (p less than 0.001). The average values for blood flow velocity in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns, and greater than or equal to 150 microns in diameter were 12.9 +/- 1.3, 24.6 +/- 3.4, 42.1 +/- 4.7, and 59.9 +/- 5.3 mm/s, respectively. Blood flow rate was calculated as a product of the cross-sectional area and the flow velocity. The blood flow rate increased exponentially as the pial artery diameter increased (y = 2.71 X 10(-4) x2.98). The average values for blood flow rate in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns and greater than or equal to 150 microns in diameter were 12.8 +/- 1.5, 122.1 +/- 24.8, 510.2 +/- 74.8, and 1524.2 +/- 174.4 10(-3) mm3/s, respectively. Hemorheological parameters such as the wall shear rate and Reynolds' number were also calculated. The data obtained provide a useful basis for further investigations in the field of cerebral circulation.