Antidromic burst activity of locus coeruleus neurons during cortical spreading depression

The electrical activity of locus coeruleus neurons was investigated during cortical spreading depression in urethane-anaesthetized rats. Cortical spreading depression was induced by a direct application of 1-3 M KCl solution to the surface of the cerebral cortex. The occurrence of cortical spreading depression was assessed by recording negative d.c. shifts and in some experiments by monitoring the extracellular potassium concentrations. The mean spontaneous firing rate of locus coeruleus neurons was significantly reduced during cortical spreading depression. Approximately 60% of locus coeruleus neurons recorded during cortical spreading depression revealed anomalous burst activity consisting of multiple initial segment spikes as well as full initial segment-somatodendritic spikes with a marked initial segment-somatodendritic break. Each spike of the cortical spreading depression-related burst activity occurred at intervals ranging from 15.0 ms to 90.1 ms (34.9 +/- 0.5 ms). The burst activity appeared unpredictably at variable intervals in a phasic or tonic manner during cortical spreading depression. The cortical spreading depression-related burst activity of locus coeruleus neurons mimicked antidromic spikes induced by train stimulation of the cerebral cortex at short interspike intervals during iontophoretic application of GABA to locus coeruleus neurons, whereas it was totally different from synaptically-activated burst activity induced by tail pinch. The full spikes and initial segment spikes in the cortical spreading depression-related burst activity failed to collide with cortically elicited antidromic spikes, even when they appeared within the collision interval. The proportion of initial segment spikes in the cortical spreading depression-related burst activity was reduced following an increase in membrane excitability by iontophoretic application of glutamate, and increased during a decreased membrane excitability by GABA application. The antidromic burst activity of locus coeruleus neurons also appeared for a short time during cortical spreading depression prior to the occurrence of seizure waves induced by GABA antagonists, while the burst activity could not be observed during seizure activity. These results indicate that the cortical spreading depression-related burst activity was of antidromic origin and that the marked initial segment-somatodendritic break in spontaneous spikes of locus coeruleus neurons during cortical spreading depression was due to reduced excitability of the somatodendritic membrane. The cortical spreading depression-related burst activity may cause release of a large amount of noradrenaline in vast regions of locus coeruleus terminal fields through the numerous axon collaterals, thereby playing a role in functional changes of brain neurons related to cortical spreading depression.

Extracellular secretion of Escherichia coli heat-stable enterotoxin I across the outer membrane

Escherichia coli heat-stable enterotoxin Ip (STIp) is an extracellular toxin consisting of 18 amino acid residues that is synthesized as a precursor of pre (amino acid residues 1 to 19), pro (amino acid residues 20 to 54), and mature (amino acid residues 55 to 72) regions. The precursor synthesized in the cytoplasm is translocated across the inner membrane by the general export pathway consisting of Sec proteins. The pre region functions as a leader peptide and is cleaved during translocation. However, it remains unknown how the resulting peptide (pro-mature peptide) translocates across the outer membrane. In this study, we investigated the structure of the STIp that passes through the outer membrane to determine how it translocates through the outer membrane. The results showed that the pro region is cleaved in the periplasmic space. The generated peptide becomes the mature form of STIp, which happens to have disulfide bonds, which then passes through the outer membrane. We also showed that STIp with a carboxy-terminal peptide consisting of 3 amino acid residues passes through the outer membrane, whereas STIp with a peptide composed of 37 residues does not. Amino acid analysis of mutant STIp purified from culture supernatant revealed that the peptide composed of 37 amino acid residues was cleaved into fragments of 5 amino acid residues. In addition, analyses of STIps with a mutation at the cysteine residue and the dsbA mutant strain revealed that the formation of an intramolecular disulfide bond within STIp is not absolutely required for the mature region of STIp to pass through the outer membrane.

RETRACTED ARTICLE: Nicardipine inhibits amrinone-enhanced contractility in fatigued diaphragm

The purpose of this study was to examine the effect of amrinone, a bipyridine derivative, with and without nicardipine, a calcium channel blocker, on the contractility of fatigued diaphragm in dogs. Twenty dogs were divided into two groups of ten each: amrinone group (group A) and combined amrinone and nicardipine group (group AN). Diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. Diaphragmatic contractility was assessed from changes in transdiaphragmatic pressure (Pdi). In group A, after producing fatigue, amrinone (0.75 mg·kg(-1) loading dose plus 10 μg·kg(-1)·min(-1) maintenance dose) was administered iv. In group AN, nicardipine 5 μg·kg(-1)·min(-1) was infused iv simultaneously with amrinone during this period. After diaphragmatic fatigue, Pdi at low-frequency (10-30 Hz) stimulation decreased compared with the prefatigue values (P<0.05), whereas no change in Pdi was observed at high-frequency (50-100 Hz), stimulation. The Pdi at each stimulus were increased compared with the fatigued values (P<0.05) by administering amrinone, and returned to these values after this agent was discontinued. The Pdi values at any frequency of stimulation did not change when amrinone was administered with nicardipine. Our results suggest that amirinone may enhance contractility in fatigued diaphragm via its effect on transmembrane calcium movement.

Experimental bronchiolitis obliterans induced by in vivo HVJ-liposome-mediated endothelin-1 gene transfer

BACKGROUND

Bronchiolitis obliterans (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. Bronchiolitis obliterans has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1), initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB.

METHODS

We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglutinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 protein were coencapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fusion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with beta-galactosidase gene was introduced. The expression of ET-1 and beta-galactosidase was assessed by immunohistochemistry.

RESULTS

Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of beta-galactosidase gene, indicating beta-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duct and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1-like immunoactivities were seen in the airway epithelial, hyperplastic connective tissue, and alveolar cells. No histopathologic changes were seen in the control animals.

CONCLUSIONS

These results suggested that ET-1 may play an important role in the pathogenesis of OB. The effective pharmacologic antagonist or inhibitor may possibly control the progression of disease in patients of OB.

Springtime peaks of trace metals in Antarctic snow

Drifting snow samples were collected at Asuka Station (71 degrees 32'S, 24 degrees 08'E, 930 m above sea level) over a period from July to December 1991; 36 elements (including Na, Mg, K, Ca, Fe, Al, Li, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Se, Rb, Sr, Cd, Pb, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th) in snow were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) by direct sample introduction. Concentrations of Cl-, NO3-, and SO(4)2- in the snow were also determined by ion chromatography. In late September to early October, there was a pronounced peak concentration of most of the elements together with non-sea salt sulfate. Enrichment factor analyses suggest that Na, Mg, Ca, K, and Sr are of marine origin and Al, Fe, Mn, Rb, Cr, Ni, Ga, V, and all the rare earth elements are of crustal origins. Volcanic eruption of Mt. Pinatubo (June 1991) and Mt. Hudson (August 1991) could be the reason for the precipitation of Pb, Cd, Cu, Zn, and Se together with non-sea salt sulfates in the austral spring at Asuka Station.

A simple method for recovering the motile spermatozoa from extremely low quality sperm samples

Recovery of motile spermatozoa from extremely low quality samples for use in the intracytoplasmic sperm injection (ICSI) procedure is difficult. To solve this problem we developed a simple method to recover the motile spermatozoa using a 3% polyvinylpyrrolidone (PVP) droplet. After depositing a sperm pellet into this slightly viscous droplet, motile spermatozoa readily swam out to the clear area while immotile spermatozoa dispersed to a lesser extent, so that motile and immotile cells became clearly separated from each other. A total of 36 ICSI cycles using spermatozoa with extremely low quality characteristics were performed. We recovered the motile spermatozoa from all sperm samples from two sources of poor quality spermatozoa. Thirty-one cycles of ICSI with ejaculate resulted in fertilization and pregnancy rates of 54 and 29% respectively. Five cycles of ICSI with frozen-thawed epididymal spermatozoa resulted in fertilization and pregnancy rates of 70 and 60% respectively. The 3% PVP droplet method is very simple and easy to perform, so it may be useful for recovering the motile spermatozoa from extremely low quality sperm samples used for ICSI.

Granisetron reduces incidence of nausea and vomiting after breast surgery

BACKGROUND

Postoperative nausea and vomiting (PONV) remains a troublesome problem. The study was performed to evaluate the antiemetic efficacy of prophylactic granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, on the incidence of PONV in patients undergoing general anaesthesia for breast surgery.

METHODS

In a randomized, placebo-controlled, double-blind study, 50 female patients, 45-68 years, were given a single dose of either placebo (saline, n = 25) or granisetron (40 micrograms.kg-1, n = 25) intravenously over 2-5 min immediately before the induction of anaesthesia. Postoperatively, during the first 24 hours after anaesthesia, the incidence of PONV and adverse events was recorded.

RESULTS

The treatment groups were similar for patient demographics, types of surgery, anaesthetic and postoperative management. Postoperatively, the incidence of PONV was 48% and 16% after administration of placebo and granisetron, respectively (P < 0.05). No differences in the incidence of other adverse events were observed between the two groups.

CONCLUSION

Granisetron is an effective antiemetic for preventing PONV in patients undergoing general anaesthesia for breast surgery.

Overnight suppression of parathyroid hormone and bone resorption markers by active absorbable algae calcium. A double-blind crossover study

In order to study the effect of Ca supplementation on the nocturnal rise of PTH and bone resorption, a double-blind, placebo-controlled study was carried out on 9 healthy male volunteers. Regimen A consisted of an oral dose of 150 mg Ca as AAACa after each meal and 450 mg at bedtime; B consisted of 300 mg after each meal and C was placebo. Plasma ionized Ca was significantly higher in A than in B at 6 a.m. the next morning and urinary Ca/Cr after 5 days was higher in A than in B and C. Plasma intact PTH fell by 19 +/- 4 pg/ml in A, 8 +/- 7 in B, and 1 +/- 7 after 1 day, and significantly decreased by 29 +/- 8 in A, increased by 11 +/- 11 in B, and 5 +/- 7 in C after 5 days (A and B, and A and C, p = 0.0242 and 0.0433, respectively), with increases of % tubular reabsorption of phosphorus. Urinary excretion of cross-linked collagen degradation product (Crosslaps) was 40 +/- 10% of the baseline in A, 97 +/- 22 in B, and 173 +/- 30 in C (A and C, P = 0.0061) after 5 days. Systolic blood pressure at 6 a.m. fell by 17 +/- 4 mmHg A, 24 +/- 3 in B, and 4 +/- 2 in C. Highly biologically available AAACa effectively suppressed nocturnal rise of PTH and bone resorption markers in 5 days.

Granulocyte colony-stimulating factor and interleukin-6-producing lung cancer cell line, LCAM

BACKGROUND AND OBJECTIVES

We describe a case of granulocyte colony-stimulating factor (GCSF) and interleukin-6 (IL-6)-producing lung cancer.

METHODS

A 53-year-old man underwent left upper lobectomy under diagnosis of lung cancer. The tumor obtained by a preoperative biopsy was analyzed.

RESULTS

Preoperative data showed leukocytosis with left-shift of leukocytic morphology and thrombocytosis and an elevated serum GCSF level. Histological examination revealed poorly differentiated adenocarcinoma. A cell line, named LCAM, was established from the tumor and the cytokines in the culture medium were measured by enzyme immunoassay. GCSF and IL-6 were produced in large amounts by LCAM, but granulocyte-macrophage colony-stimulating factor (GMCSF) and interleukin-3 (IL-3) were not. A proportion of LCAM expressed GCSF receptor on the cell surface, but IL-6 receptor could not be detected. LCAM proliferation was inhibited in the culture with antihuman GCSF antibody in a dose-dependent manner.

CONCLUSIONS

We suggest that LCAM proliferation is positively regulated by GCSF.

[Correction of urinary calcium levels for urine osmotic pressure]

The usefulness of the urinary calcium/creatinine (Ca/Cr) ratio, the oldest marker of bone resorption, is limited because of the influence of sodium intake and urine volume. The urinary Ca/Cr ratio was therefore compared with urinary calcium corrected for the urine osmotic pressure (Ca/OSM). Significant correlations are found between the Ca/Cr ratio and both creatinine (r = -0.386) and osmotic pressure (r = -0.473) in random urine samples from normal subjects, but similar correlations were not found for urine Ca/OSM. No significant correlation was found between Ca/OSM and Na/OSM, but the correlation coefficient between Ca/Cr ratio and Na/Cr ratio was 0.399. Thus, the Ca/Cr ratio is affected by urinary volume and sodium concentration, but the Ca/OSM ratio is not. The Ca/OSM ratio may therefore be a more accurate marker of bone resorption, because one of the main components of urinary osmotic pressure is sodium that inhibits tubular calcium reabsorption. The Ca/OSM ratios measured from 24-hour urine samples were found to be strongly correlated with the values measured from samples obtained during sleep (sleep urine, 0.823) and were slightly less strongly correlated with the values measured from second morning samples (0.641). Because bone resorption is especially active at night, the Ca/OSM ratio in sleep urine may be the most sensitive marker of bone resorption. The Ca/OSM ratio in sleep urine samples increased with age in normal women.

Granisetron reduces postoperative nausea and vomiting throughout menstrual cycle

PURPOSE

The incidence of postoperative nausea and vomiting (PONV) is influenced by menstruation. This study was undertaken to assess the efficacy of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for preventing PONV in patients during two different phases of menstrual cycle.

METHODS

One hundred twenty female patients undergoing general anaesthesia for major gynaecological surgery were divided according to the phase of menstrual cycle into two groups: day one to eight (menstrual) and day nine to end of the cycle (non-menstrual) groups. In a randomized, double-blind manner, the patients received placebo (saline) or 40 micrograms.kg-1 granisetron i.v. immediately before the induction of anaesthesia. All patients received a standardized general and epidural anaesthesia and epidural morphine plus bupivacaine for postoperative analgesia. The incidence of PONV and other adverse events was recorded during the first 24 hr after anaesthesia.

RESULTS

The treatment groups were similar with respect to patient demographics, types of surgery, anaesthetics administered and analgesics used postoperatively. The incidence of PONV was 72% and 32% in patients during menstruation receiving placebo or granisetron (P < 0.05), and was 46% and 20% in those during non-menstruation, respectively (P < 0.05). No differences in the incidence of other adverse events were observed among the groups.

CONCLUSION

Granisetron was effective in reducing the incidence of PONV in both phases of the menstrual cycle studied.

Increased nitric oxide levels in exhaled air of rat lung allografts

In organ transplantation nitric oxide has been reported to be involved in allograft rejection. We examined in a rat lung transplantation model whether nitric oxide is overproduced in acute rejection and can be detected in exhaled air. Thirteen rat right lung transplants were separated into three groups: group 1 (n = 5), untreated allografts (Brown-Norway [RT1n] to Lewis [RT1l]); group 2 (n = 4), cyclosporine-treated allografts; and group 3 (n = 4), isografts (Lewis to Lewis). We examined exhaled nitric oxide levels with a chemiluminescence analyzer and chest roentgenograms on days 2 through 5. Histologic samples were obtained on days 3 and 5. On day 5, the recipients were killed and we measured exhaled nitric oxide from the right and left lungs separately. Blood samples were also obtained for measurement of serum nitrite/nitrate. The exhaled nitric oxide level in untreated allografts increased significantly from day 5 (63.9 +/- 39.2 ppb, p = 0.0095) and was significantly higher than that in treated allografts (9.1 +/- 1.6 ppb) (p = 0.0085) and isografts (6.9 +/- 0.5 ppb) (p = 0.0068). The nitric oxide level in untreated allografts (826.5 +/- 416.1 ppb) was 75 times as high as that from the contralateral normal left lungs (11.2 +/- 2.6 ppb) (p = 0.0118). The level of exhaled nitric oxide correlated significantly with the histologic rejection grade (p = 0.0001). There was no significant difference in the serum nitrite/nitrate levels between allografts and isografts. These data suggest that increased exhaled nitric oxide levels might reflect acute rejection in lung transplants.

Saccular aneurysm in the right-sided aortic arch: a successfully corrected case

We report the surgical treatment of a rare case of true aortic aneurysm in a right-sided aortic arch. A 49-year-old female patient with obstructive respiratory problems demonstrated a true aneurysm with a diameter of 58 mm located at the right-sided aortic arch between the right carotid artery and right subclavian artery. Surgery was successfully performed by replacing the arch including the aneurysm with a prosthetic graft. The positions of true aneurysms in the right-sided aortic arch can be divided into two subtypes: first, the transverse arch between the right carotid artery and right subclavian artery, and second, the base of the subclavian artery, the Kommerell's diverticulum. The region is informative for consideration of the surgical approach toward aneurysms of this entity.

Involvement of MAP kinase and c-fos signaling in the inhibition of cell growth by somatostatin

Somatostatin significantly suppressed cell growth of the mouse insulinoma-derived cell line MIN6. MIN6 cells exhibited high-affinity binding of somatostatin with 50% inhibitory concentration value of 0.9 nM. RNA blot analysis revealed that MIN6 cells expressed only SSTR3 among the five somatostatin receptors so far identified. Treatment of MIN6 cells with somatostatin significantly reduced the serum-induced c-fos expression levels. On the other hand, somatostatin (100 nM) treatment of MIN6 cells cultured in medium containing 10% serum transiently increased c-fos expression levels to 282 +/- 4.7% and then significantly decreased them to 27 +/- 7.6% of the levels before treatment. Mitogen-activated protein (MAP) kinase activity transiently increased to 656 +/- 91.2% and decreased thereafter to 39 +/- 13.3% of the activity before the addition of somatostatin (100 nM) into the medium. In addition, the stimulatory effect of somatostatin on c-fos expression and MAP kinase activity (early effect) was not altered by pertussis toxin (PTX), whereas the suppressive effect of somatostatin on c-fos expression and MAP kinase activity (late effect) was mitigated by PTX. These findings suggest that an inhibition of c-fos expression mediated by cross talk between PTX-sensitive G protein signaling and receptor tyrosine kinase signaling is one of the mechanisms by which somatostatin inhibits cell growth in MIN6 cells.

Failure to down-regulate Bcl-2 protein in thymic germinal center B cells in myasthenia gravis

The most unusual characteristic of myasthenia gravis (MG) is that the thymus has germinal centers (GC). Cultured thymic lymphocytes from MG patients spontaneously produce anti-acetylcholine receptor antibodies, indicating that autoreactive B cells have escaped negative selection. To investigate the underlying mechanism, we examined the expression of the apoptosis-related protein Bcl-2 in GC B cells (defined as CD19+ CD38+ cells) in the thymus in 14 MG patients using three-color flow cytometry. GC in MG patients did not show the normal down-regulation of Bcl-2 (the frequency of Bcl-2+ GC B cells in the MG thymus and in control tonsils 54.3 +/- 16.2% versus 20.6 +/- 8.0%; mean +/- SD. p < 0.0001). In contrast, Bcl-2 in GC in the mediastinal lymph nodes from four patients was down-regulated to a relatively normal level. Using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method to detect DNA fragmentation in situ, the frequency of TUNEL+ cells in GC in the MG thymus was lower than in control tonsils. These results suggest that autoreactive B cells which normally undergo apoptosis in GC may survive because of Bcl-2 up-regulation in this unusual location.

Serial changes of hemostasis in aneurysmal subarachnoid hemorrhage with special reference to delayed ischemic neurological deficits

This study was undertaken to elucidate comprehensively the serial changes occurring in hemostatic systems after aneurysmal subarachnoid hemorrhage (SAH) and thereby to ascertain whether the examination of the integrity of these systems is helpful in predicting delayed ischemic neurological deficits (DINDs). The authors examined 117 patients admitted to the hospital within 24 hours after onset of SAH. Blood samples were collected from each patient on Days 0 (at admission), 3, 6, 14, and 30. A number of hemostatic parameters were examined in these samples, and the relationships between their changes and DINDs were assessed. Eighteen (15.4%) of the patients exhibited DINDs, and their frequency increased as the severity of subarachnoid clotting increased. Also, the frequency of DINDs was significantly higher in the patients with hydrocephalus on initial computerized tomography (CT) scans than in those without hydrocephalus. Regarding the hemostatic parameters at admission, there was no significant difference between the patients with and without DINDs. On Day 3, however, the fibrinogen and D-dimer levels were higher in the patients with than in those without DINDs. The fibrinogen and thrombin-antithrombin complex levels on Day 6 and the D-dimer level on Day 14 in the patients with DINDs were higher than the corresponding levels in those without DINDs. Multivariate analyses revealed that the following variables (in order of importance) were independent predictors of DINDs: the levels of D-dimer on Day 3, fibrinogen on Day 6, and the presence of hydrocephalus on admission. These data indicate that the levels of hemostatic parameters in concert with the CT findings may enable us to predict the appearance of DINDs.

[Ultrastructural study of lens in rat hereditary cataract by quick-freezing and deep-etching]

The cytoskeleton of lens fiber cells in rats with hereditary cataract (ICR/f) was studied by quick-freezing and deep-etching. Two kinds of filamentous structure with diameters of 5 and 10 approximately 15 nm were observed in the cortical fiber cells. They showed meshwork structures which were buried in globular particles. These filamentous structures were mostly absent in the nucleus fiber cells, but aggregated and fused globular particles with diameters of 10 approximately 20 nm were observed. Small cavities were sometimes observed in their cytoplasm. Between lens fiber cells, many globular structures were also seen. These changes might represent the degeneration of the lens fiber cells in cataract lenses.

Granulocyte colony-stimulating factor and interleukin-6-producing lung cancer cell line, LCAM

BACKGROUND AND OBJECTIVES

We describe a case of granulocyte colony-stimulating factor (GCSF) and interleukin-6 (IL-6)-producing lung cancer.

METHODS

A 53-year-old man underwent left upper lobectomy under diagnosis of lung cancer. The tumor obtained by a preoperative biopsy was analyzed.

RESULTS

Preoperative data showed leukocytosis with left-shift of leukocytic morphology and thrombocytosis and an elevated serum GCSF level. Histological examination revealed poorly differentiated adenocarcinoma. A cell line, named LCAM, was established from the tumor and the cytokines in the culture medium were measured by enzyme immunoassay. GCSF and IL-6 were produced in large amounts by LCAM, but granulocyte-macrophage colony-stimulating factor (GMCSF) and interleukin-3 (IL-3) were not. A proportion of LCAM expressed GCSF receptor on the cell surface, but IL-6 receptor could not be detected. LCAM proliferation was inhibited in the culture with antihuman GCSF antibody in a dose-dependent manner.

CONCLUSIONS

We suggest that LCAM proliferation is positively regulated by GCSF.

An immunocytochemical study of changes in the human erythrocyte membrane skeleton produced by stretching examined by the quick-freezing and deep-etching method

A quick-freezing and deep-etching method in combination with erythrocyte splitting was used to examine the cytoplasmic aspect of whole-mount human erythrocyte membranes. Various external forces induced alterations in membrane skeletal organisation during the splitting procedure. The initial change was elongation in the peripheral part of the membrane skeleton, examined by immunostaining with a monoclonal antispectrin antibody. Under severe stretching conditions, a linear rearrangement of filamentous components was evident; these were disposed parallel to the rim of the erythrocyte, while the central part of the concavity exhibited a more compacted structure. These changes resulted in a different distribution of membrane skeletal components between central rigid and peripheral flexible areas in biconcave erythrocytes. It is suggested that the reversible membrane skeletal changes in the flexible areas which resist the external forces are important for maintaining the normal framework of biconcave human erythrocytes.

Detection of delayed cerebral vasospasm, after rupture of intracranial aneurysms, by magnetic resonance angiography

OBJECTIVE

The goal of this study was to assess the value of magnetic resonance angiography (MRA), compared with conventional angiography, in the diagnosis and follow-up monitoring of delayed cerebral vasospasm after subarachnoid hemorrhage resulting from rupture of intracranial aneurysms.

METHODS

For 32 patients undergoing examination by both MRA and conventional angiography during the period of risk for vasospasm, on the same day, the frequency and severity of and sequential changes in vasospasm were evaluated. The three-dimensional time-of-flight method was used. MRA was performed three times, i.e., before, during, and after the period of risk for vasospasm. Conventional angiography was performed twice, i.e., at admission and during the period of risk for vasospasm. Vasospasm was assessed at 22 regions of the cerebral arteries, including the bilateral anterior cerebral (A1, A2, and A3 segments), middle cerebral (M1, M2, and M3 segments), internal carotid (C1 and C2 segments), posterior cerebral (P1 and P2 segments), and posterior communicating arteries.

RESULTS

Seven patients were excluded because of poor MRA images. Twenty-two of 25 patients (125 arteries) showed vasospasm in conventional angiograms. Nineteen of the 22 patients also showed vasospasm in MRA images; however, 57 arteries (45.6%) were diagnosed as showing vasospasm by MRA, and 59 (47.2%) could not be evaluated because of artifacts. For the remaining three patients (nine arteries, 7.2%), vasospasm could not be detected by MRA. Sequential changes in vasospasm could be well evaluated by MRA.

CONCLUSION

MRA could be useful for management of cerebral vasospasm, although it cannot become a practical alternative to conventional angiography.

Granisetron reduces the incidence and severity of nausea and vomiting after laparoscopic cholecystectomy

PURPOSE

Postoperative nausea and vomiting (PONV) are commonly observed undesirable consequences of laparoscopic cholecystectomy. This study was undertaken to compare granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, with droperidol for reducing the incidence and severity of PONV after laparoscopic cholecystectomy.

METHODS

Eighty patients, aged 25-65 yr, scheduled for elective laparoscopic cholecystectomy were enrolled in a randomized, double-blinded investigation and assigned to one of three treatment regimens: placebo (saline), 1.25 mg droperidol (approximately 25 micrograms.kg-1) or 3 mg granisetron (approximately 60 micrograms.kg-1). The study drugs were administered iv immediately before the induction of anaesthesia. A standard general anaesthetic technique was employed throughout. Nausea, vomiting and safety assessments were performed continuously during the first 24 hr after anaesthesia.

RESULTS

The incidence of PONV was 46% with placebo, 41% with droperidol and 15% with granisetron (P < 0.05; overall chi 2 test). Four patients who had received placebo and two who had received droperidol required another rescue antiemetic, compared with none who had received granisetron (P < 0.05). Adverse events postoperatively were not different among the groups.

CONCLUSION

Granisetron is more effective than droperidol and placebo for reducing the incidence and severity of PONV after laparoscopic cholecystectomy.

Membrane skeletons in avian erythrocytes as revealed by the quick-freezing and deep-etching method

Ultrastructure of chicken erythrocytes were examined by the quick-freezing and deep-etching (QF-DE) method. Some erythrocytes were fixed with paraformaldehyde and prepared with erythrocyte-splitting method or saponin treatment to remove soluble proteins before quick-freezing. Others were prepared in the cytosol buffer with the erythrocyte-splitting method to obtain natural state of cytoskeletons. Non-expanding membrane skeletons were highly condensed on the cytoplasmic side of lipid membrane in the paraformaldehyde-fixed specimens. Under unilateral extension of the specimens, long stretched filaments were connected alternately with condensed filamentous or granular structures under erythrocyte membranes. As the membrane skeletons got closer to the marginal bands, they become more dense network structures. Moreover, in the fresh unfixed specimens, dense networks of filaments were localized underlying erythrocyte membranes in a relatively intact state. Fine filaments connected the marginal microtubule bands to the cytoplasmic sides of erythrocyte membranes. The different distribution of each cytoskeletal component and the association of these structures may support the elliptocytic shape of chicken erythrocytes and resist the dynamic circumstance.

Bacillus Calmette-Guérin enhances production and secretion of type IV collagenases in peripheral blood mononuclear cells

Intravesical administration of bacillus Calmette-Guérin (BCG) is an effective and widely accepted treatment for superficial bladder cancer. Rapid progression of the disease after BCG therapy, however, has been reported in some cases refractory to the treatment. We examined whether BCG treatment and coexistence of peripheral blood mononuclear cells (PBMCs) alter the invasive potential of bladder cancer cells. Production and secretion of two type IV collagenases, matrix metalloproteinase (MMP) 2 and MMP 9, by PBMCs from five healthy donors or bladder cancer cells (T24, JTC 30, and JTC 32) were evaluated by gelatin zymography, western blot analysis, and northern blot analysis. Invasion of bladder cancer cells was also examined using reconstituted basement membrane (Matrigel). BCG (5, 50, and 500 micrograms/ml) had no effect on secretion of MMP 2 and MMP 9 by bladder cancer cells, but increased the production and secretion of MMP 9 by PBMCs in a dose-dependent manner. The coexistence of PBMCs increased invasion of T24 cells and BCG further enhanced the invasion. Thus, BCG promotes invasion of bladder cancer cells under certain conditions. An increase in the secretion of MMP 9 by PBMCs may account in part for the effect.