Suppression of cell invasion on human malignant glioma cell lines by a novel matrix-metalloproteinase inhibitor SI-27: in vitro study

Matrix metalloproteinase (MMP) has come to be highlighted by its close relation to the cell invasion of gliomas. Suppression of MMP activity in malignant glioma cells would be meriting to local delivery of genes or chemotherapeutic agents. In this study, we employed a novel MMP inhibitor, SI-27 to investigate inhibition of cell invasiveness in human malignant glioma cell lines, U87MG, U251MG, and U373MG. We evaluated with zymogram, reverse zymogram, and cell invasion assay after exposure of SI-27 for 24 h followed by preliminary MTT assay to find non-cytotoxic dose range, 5, 10, 50, 100 microg/ml compared with non-treatment group as the control. Common to three glioma cell lines, zymogram disclosed that expressions of MMP-2 and -9 were suppressed in a dose-dependent fashion, meanwhile those of tissue inhibitor of MMP (TIMMP) in reverse zymogram were not. The numbers of invading cells through Boyden chamber were significantly reduced in a dose-dependent manner, while those with 5 microg/ml were not diminished common to those three lines. In conclusion, dose concentration ranging 10-100 microg/ml of SI-27 inhibited MMP-2 and -9 mediated cell invasiveness in malignant glioma cell lines. This is the first report for chemotherapeutic effect of SI-27 on glioma cells.

Drug-induced apoptosis by anti-microtubule agent, estramustine phosphate on human malignant glioma cell line, U87MG; in vitro study

The drug effect of estramustine phosphate (EMP), an anti-microtubule agent on human glioma cells has been studied with the focus being mainly its cytotoxity or its targeting of organelles. However, the pharmacological knowledge of estramustine with respect to its cytotoxity and mechanism is limited. To acquire such knowledge, the present study investigates the ability of EMP to induce apoptosis in a human malignant glioma cell line. Transmission electron microscope (TEM) images were examined to monitor periodic changes. Agarose gel electrophoresis was also examined. Cellular DNA fragmentation ELISA was performed to investigate the DNA fragmentation rates and an MTT assay was studied to evaluate the ID50. A TEM study revealed condensing and fragmentation of the chromatin. Laddering of the bands was observed in all EMP exposure groups in agarose gel electrophoresis. DNA fragmentation in all EMP groups began at 0.5 h following an exposure with EMP and increased in a dose- and time-dependent manner as revealed by DNA ELISA fragmentation. ID50 at 24 h was 5.0 microM according to the MTT assay, a value close to 4.8 microM of ID50 was revealed by the DNA fragmentation assay. None of the above mentioned changes was observed in the control group. These results indicated that EMP caused a drug-induced apoptosis in the human malignant glioma cell line, U87MG.

Intracranial malignant meningioma with abdominal metastases associated with hypoglycemic shock: a case report

A thirty-year-old male with an intracranial malignant meningioma, first diagnosed 9 years ago, with three recurrences was admitted with a hypoglycemic shock. The blood glucose level was 17 mg/dl, requiring treatment with high doses of intravenous and oral dextrose for improvement. A large metastatic tumor in the liver was noted. All hormones and peptides influencing blood glucose levels were in their normal levels. Chemo-embolization and injection of anti-cancer drugs was employed in the management of the metastatic tumor. Positron emission tomography was performed to measure the glucose metabolism of the abdominal tumor and it indicated that glucose consumption within the tumor was much elevated than the surrounding abdominal organs. Hypoglycemia secondary to primary hepatoma or islet-cell cancer has been frequently described, but a complication of metastatic meningioma is an exceedingly rare event. Elevated glucose consumption within the tumor might be addressed as one of the reasons for hypoglycemia, not due to the elevated serum levels of insulin or IGF, but due to the closely related blood glucose level.

Evaluation of the intratumoral vasculature of hepatocellular carcinoma by power doppler sonography: advantages and disadvantages versus conventional color doppler sonography

BACKGROUND

To determine whether a difference exists in the relative ability of power Doppler sonography and conventional color Doppler sonography to detect the intratumoral vasculature of hepatocellular carcinoma based on lesion size and location.

METHODS

Sixty patients with 88 hepatocellular carcinoma lesions that showed tumor staining on angiography and were enhanced on dynamic computed tomography were evaluated. Power Doppler sonography and color Doppler sonography were used to detect the intratumoral vasculature, and their sensitivity to blood flow was evaluated.

RESULTS

Power Doppler sonography showed a superior detection rate for lesions smaller than 2 cm and located 4-8 cm from the abdominal surface in the right hepatic lobe as compared with color Doppler sonography (p < 0.01). Neither power Doppler sonography nor color Doppler sonography depicted the intratumoral vasculature of lesions located more than 8 cm from the abdominal surface (n = 14). Both color Doppler imagings exhibited a low detection rate for lesions in the left hepatic lobe (n = 31, p < 0.01).

CONCLUSIONS

Power Doppler sonography should be applied in the evaluation of small or intermediate depth lesions because it is more sensitive to these lesions than color Doppler sonography, but it is not useful for left lobe and deep lesions.

[Preliminary study of calculating cerebral arterial blood oxygen saturation using MRI]

To assess whether cerebral arterial blood oxygen saturation (SaO2) can be calculated by EPI, we examined the relationship between peripheral SaO2 and T2+ signal intensity (SI) changes in the brain in three normal subjects, using 1.5 Tesla MRI. To decrease SaO2, hypoxia was induced by 100% helium-gas inhalation (60 sec). SI declined as SaO2 decreased during helium inhalation, while rapid recovery of SI to the baseline was noted with recovery from hypoxia. The differential effective transverse relaxation rate was closely correlated with SaO2 (r > 0.94). Consequently, using MRI, we were able to calculate arterial SaO2.

Scintigraphic prediction of resistance to radiation and chemotherapy in patients with lung carcinoma: technetium 99m-tetrofosmin and thallium-201 dual single photon emission computed tomography study

BACKGROUND

Various prognostic markers for lung carcinoma have been proposed, but to the authors' knowledge none is noninvasive and convenient for clinical use. The current study examined the utility of several radiotracers for the prediction of multidrug resistance (MDR) and radioresistance in patients with lung carcinoma.

METHODS

Thirty patients with untreated lung carcinoma underwent a dual isotope single photon emission computed tomography (SPECT) scan at 10 minutes and 120 minutes after the injection of technetium-99m ((99m)Tc)-tetrofosmin ((99m)Tc-TF) (370 megabecquerels [MBq]) and thallium-201 ((201)TlCl) (111 MBq). Retention of each tracer was evaluated semiquantitatively. Using radiation and chemotherapy (cisplatin plus etoposide), the patients either were treated sequentially (n = 12) or concurrently (n = 18). The relation between therapeutic response and retention of each tracer was analyzed. The detectability of radioresistance was examined.

RESULTS

In patients treated with sequential therapy, the response to radiation was predicted by (99m)Tc-TF retention, whereas (201)Tl retention was found not to be predictive. Regardless of whether the sequential or concurrent protocol was applied, 14 of 18 tumors with high (99m)Tc-TF retention (>/= 15%) exhibited a favorable response to chemoradiotherapy whereas all 12 tumors with low (99m)Tc-TF retention (</= 15%) did not respond to the therapy. In contrast, (201)Tl retention was not found to be a predictive factor.

CONCLUSIONS

The employed SPECT method is a useful tool for the in vivo prediction of radioresistance, P-glycoprotein (P-gp), and non-P-gp MDR in lung carcinoma. Low (99m)Tc-TF retention serves as a strong predictor of therapeutic resistance. High (99m)Tc-TF retention implies a favorable response. (201)Tl did not appear to be a predictive factor but is required for localization of the lesion on SPECT imaging.

Changes in the findings of dynamic MRI by preoperative CAF chemotherapy for patients with breast cancer of stage II and III: pathologic correlation

Preoperative neoadjuvant chemotherapy is essential for treatment of patients with breast cancer who have a large tumor mass and/or regional lymph node involvement, in terms of both tumor shrinkage and further improvement of the survival rate. In order to safely perform breast-conservation treatment for these patients, a detailed diagnostic procedure for precisely evaluating the therapeutic response is needed. Dynamic magnetic resonance imaging (MRI) is thought to be important in the evaluation of responses to neoadjuvant therapy in patients with considerably large tumors, however, few studies have detailed the changes, as depicted by dynamic MRI, that can be expected with neo-adjuvant chemotherapy. The purpose of this study was to document the changes that occur in response to neoadjuvant chemotherapy and to correlate them with the pathological findings observed in the surgical specimen. The study was performed at Kochi Medical School Hospital from 1995 to 1998. The series consisted of 31 patients with stage II and III breast cancer. Prior to and after 1-5 courses of neoadjuvant chemotherapy, dynamic MRI examinations were performed. Eight of the time-intensity curves for the 10 grade 1a tumors flattened during neoadjuvant chemotherapy, while two remained the same. Six of the curves flattened for the 14 grade 1b tumors, 7 remained the same, and one spiked. And for the seven grade 2 tumors, two of the curves flattened and five remained the same (p=0.0340). In the five grade 1 tumors, the mean after/before normalized peak signal intensity ratio was 0.42+/-0.22. In the 18 grade 2 and 8 grade 3 tumors, the mean normalized signal intensity ratios were 0.59+/-0.28, 0.88+/-0.10, respectively (p<0.05). In the 15 tumors that showed shrinkage of the linear enhancement during neo-adjuvant chemotherapy, 10 had no remarkable intraductal spreading and 9 had a negative surgical margin. In the 16 tumors that had no shrinkage of the linear enhancement during chemotherapy, 13 had remarkable intraductal spreading and 12 had a positive surgical margin (p<0.05). It is concluded that dynamic MRI is a valuable tool for determining tumor response and predicting a positive surgical margin. Breast-conservation treatment can be performed for these patients by meticulous assessment using such detailed diagnostic procedures after local tumor control by combined chemotherapy with high dose-intensity.

Cavernous hemangioma of the skull in a neonate

Cavernous hemangiomas rarely occur in the calvarium and most commonly present in middle-age. Although a congenital vascular disorder can theoretically cause a diploic lesion in any age group, a calvarial cavernous hemangioma has not been reported in newborn. A 4-month-old male infant presented with a large left parietal mass that had been present since birth. Total resection was performed. Pathological examination revealed a cavernous hemangioma developing within the diploic space adjacent to prior hemorrhages. Surgery was performed in this case because of the size and persistence of the lesion. Removal of tumors of a benign nature from the calvarium can be done safely. Cavernous hemangioma of the skull in a neonate should be considered as one of the differential diagnoses in the case of suspected ossified cephalohematoma.

Extraosseous metastases of hepatocellular carcinoma detection and therapeutic assessment with Tc-99m PMT SPECT

Owing to recent advances in imaging technology and radiologic intervention, survival rates in patients with hepatocellular carcinoma have improved markedly. However, such prolonged survival has resulted in an increase in extrahepatic metastases. Tc-99m (Sn)-N-pyridoxyl-5-methyltryptophan (Tc-99m PMT), developed for hepatobiliary scintigraphy, has been used to visualize extrahepatic metastases, with most related reports limited to osseous metastases. The authors report two cases of hepatocellular cancer presenting as a hypopharyngeal metastasis and intraperitoneal dissemination along the tract of a fine-needle biopsy. Lesions undetectable on planar imaging could be visualized by Tc-99m PMT SPECT.

Relationship between ATP synthesis and 201Tl uptake in transformed and non-transformed cell lines

201Tl tumour imaging is an established procedure, but little is known about its biological significance in transformed and non-transformed cells. In investigating the relationship between 201Tl uptake and intracellular ATP, we wished to determine whether the observed difference in delayed uptake is attributable to re-uptake via Na-K ATPase by using transformed (HeLa) and non-transformed (human fibroblast: hFB) cell lines. In each cell line, ATP was measured using the Luciferin-Luciferase method (LLM). The change in 201Tl uptake was assessed under conditions of mitochondrial suppression. Additionally, we assessed whether glycolysis is involved in 201Tl uptake under conditions of mitochondrial suppression and anaerobic incubation. Re-uptake via Na-K ATPase (HeLa vs hFB: 37.3 vs 24.2%) showed a clear difference in delayed uptake between HeLa and hFB. With HeLa, 201Tl uptake decreased biphasically with a reduction in ATP levels, whereas with hFB a linear correlation was evident. Despite the suppression of mitochondrial potential, a 5% glucose loading accelerated glycolysis with HeLa, and increased ATP (10.0 +/- 4.0%) and 201Tl uptake (16.2 +/- 3.0%). Conversely, neither ATP nor 201Tl uptake increased with hFB. Our results provide evidence that 201Tl uptake in transformed cells is related to enhanced glycolysis as well as mitochondrial ATP synthesis.

Dual-isotope SPECT diagnosis of a skull-base metastasis causing isolated unilateral hypoglossal nerve palsy

We describe a 48-year-old female with an isolated unilateral hypoglossal nerve palsy caused by a skull base metastasis from breast cancer. The patient had a medical history of conservative breast therapy for breast cancer. Although the cause of such a neurological deficit includes various pathologies, the reports focusing on metastatic tumor have been limited in number. Radiologic investigation showed a mass involving both the right hypoglossal canal and the clival edge. Swelling of the hypoglossal nerve was observed in views including its canal. Three-dimensional CT images demonstrated the tumor protruding from the enlarged external orifice of the hypoglossal canal. In the present report we mentioned a nuclear medicine procedure to visualize and characterize the small, abnormal tissue in the skull base. Dual-isotope SPECT confirmed an abnormal uptake of 99mTc-HMDP around the hypoglossal canal and a 201Tl-positive elongated lesion running along the hypoglossal nerve.

Dual isotope SPECT in malignant Jacod's syndrome

A case is presented of metastatic tumor causing Jacod's syndrome: total ophthalmoplegia, blindness, and trigeminal neuralgia. Abnormal soft tissue invading the orbital apex, anterior clinoid process, and cavernous sinus was difficult to assess by CT and MRI, but dual-isotope SPECT including Tc-99m HMDP bone imaging and Tl-201 tumor imaging strongly suggested that the cause of this rare syndrome was a small metastatic tumor. Although the therapeutic effect was also difficult to assess by anatomic imaging alone, dual-isotope SPECT after radiation therapy showed a decline of tumor viability.

Malignant fibrous histiocytoma in the parietal bone

Malignant fibrous histiocytomas (MFHs) are mesenchymal tumors, usually arising in soft tissue of the extremities and are remarkably resistant to radiation and chemotherapy. A 45-year-old female presented with a rare case of MFH originating in the cranial bone manifesting as a lump in the left parietal region with no neurological abnormality. Neuroimaging revealed the presence of an osteolytic tumor in the left parietal bone invading into muscle and subdural region, penetrating through the dura. Selective external carotid angiography disclosed a marked tumor stain. Examination of the whole body excluded neoplastic disease elsewhere. The patient was treated by surgical excision, radiation, and two courses of multi-drug chemotherapy using cyclophosphamide, doxorubicin, vincristine, and prednisolone. Since there is no established treatment against this malignancy, a longer follow-up is necessary to determine whether cure has been achieved.

Dynamic MR appearance of adenoid cystic carcinoma of the breast in a 67-year-old female

We describe an adenoid cystic carcinoma on the right breast of a 67-year-old woman. Dynamic magnetic resonance (MR) imaging demonstrated a well-circumscribed round lesion with rapid and marked enhancement on T1-weighted images, without washout of the contrast agent. The enhanced area extended gradually from the margin to the center of the tumor, showing very late enhancement of the tumor center. The findings suggested a tumor with rich stromal component, including adenoid cystic carcinoma of a special type of breast cancer. Histological examination of a lumpectomy disclosed a well-circumscribed tumor consisting of ovoid, trabecular, and irregularly shaped 'nests' of tumor cells, with a focally cribriform pattern. The examination confirmed the diagnosis of adenoid cystic carcinoma of the breast.

Suppression of matrix metalloproteinase-2-mediated cell invasion in U87MG, human glioma cells by anti-microtubule agent: in vitro study

Because microtubules are important components of cell motility and intracellular transport, it is reasonable to propose that the depolymerizing effect of an antimicrotubule agent, estramustine, on glioma microtubules would modulate cell invasiveness. To determine whether matrix metalloproteinases, key factors in cell invasion, are affected by exposure to estramustine, a cell proliferation assay, a zymogram, a collagenolysis assay and a haptoinvasion assay were used in this study. The zymogram revealed that an activated (62 kDa) form of matrix metalloproteinase-2 diminished with increasing estramustine concentrations. The collagenolysis assay demonstrated approximately 2.5- to 21-fold lower rates of enzymatic activity suppressed by estramustine in a dose-dependent manner at estramustine concentrations of 1, 5, and 10 microM, compared with the control group. On the haptoinvasion assay, no statistically significant difference was seen in the 0.5 microM estramustine group, whereas 1-10 microM estramustine groups revealed significant suppression of invasion from 6 to 24 h in a dose-dependent manner. The results suggest that estramustine suppresses the invasion of U87MG cells in vitro using the decreasing available matrix metalloproteinase-2, an effect caused by the disassembly of microtubules. Suppression of the infiltrative capacity of malignant glioma cells could be of significant value in the treatment of this disease.

Subcellular distribution of thallium: morphological and quantitative study in rat myocardium

The purpose of this study is to determine the subcellular distribution of thallium (SDTl) by electron microscopy and a newly designed fixation method that makes insoluble grains of Tl visible.

METHODS

To obtain the high dose necessary for electron microscopic visualization, we employed TlCl instead of 201TlCl. EM was performed in fixed rat myocardium resected at 20 min (early phase) and 3 hr (delay phase) after intravenous injection of TlCl. To fix Tl in the cell, we used orthovanadate in our fixative. Atomic absorption spectroscopy (AAS) of Tl and quantification of subcellular distribution of 201Tl (SD201Tl) were studied to prove the propriety of our fixation.

RESULTS

AAS detected Tl in the Tl-loaded specimen but not in the control, indicating that Tl was the origin of the grains observed in the former. In the early phase, numerous grains were observed in mitochondria, sarcoplasmic reticulum (SR), myofibrils, and nuclei, but no such grains were visible in controls. In the delay phase, grains were retained in mitochondria, SR and nuclei, but not in myofibrils. Electron microscopic SDTl(%) correlated with SD201Tl(%) calculated from isolated fractions.

CONCLUSION

In both the early and delay phases, mitochondria are the major site of Tl and 201Tl uptake.

Dynamic MR appearance of benign phyllodes tumor of the breast in a 20-year-old woman

We describe a 20-year-old woman with benign phyllodes tumor of the left breast. Dynamic MRI demonstrated a multi-lobulated lesion rapidly and markedly enhanced on dynamic studies of contrast-enhanced T1-weighted imaging without washout. Histological examination of an excisional biopsy specimen obtained under local anesthesia disclosed a well-circumscribed multi-lobulated lesion, confirming the diagnosis of benign phyllodes tumor of the breast.

Thyroid storm precipitated by trauma

A 21-year-old woman presented to the emergency department complaining of head, neck, and abdominal pain after being assaulted. She denied a previous history or significant symptoms of hyperthyroidism. The physical examination was remarkable for lethargy, low-grade fever, tachycardia, facial abrasions, swelling of the anterior neck, and a tremor. A diagnosis of thyroid storm was made. An extensive work up excluded other causes of the patient's tachycardia, altered mental status, and neck swelling. A review of the clinical features and management of thyroid storm is presented. Relatively minor trauma can be a precipitating event for thyroid storm.

Targeting microtubule-associated proteins in glioblastoma: a new strategy for selective therapy

BACKGROUND

This report presents a summary of preclinical data concerning the use of estramustine, an antimicrotubule agent against human glioblastoma cells. The strategy for the investigation of estramustine is predicated on the unique affinity of this agent for microtubule-associated proteins (MAPs).

METHODS

A series of laboratory investigations were used to demonstrate antiproliferative effects (MTT assay, colony forming assay, thymidine incorporation), cell cycle synchronization (flow cytometry), intracellular localization of binding sites (immunocytochemistry, electron microscopy), and activity in subcutaneous xenografts of human glioblastoma.

RESULTS

Estramustine has potent in vitro activity against human glioblastoma cells and can enhance the cytotoxic effects of ionizing radiation. Estramustine-binding protein was abundantly expressed in glioblastoma cells and may contribute to the selective effects of estramustine on neoplastic cells. This agent has activity against subcutaneous xenografts of human glioblastoma. Synthesized novel estrogen carbamates also can inhibit proliferation of glioblastoma cells.

CONCLUSIONS

Cytoskeletal elements (MAPs) of glioblastoma cells may provide a useful target for therapy with agents like estramustine because of the potent antimitotic effects of this agent and its affinity to a protein that is expressed in glioma cells. These observations have stimulated a search for other estrone carbamates with antimitotic activity that exceeds more conventional antimicrotubule agents.

Estramustine in malignant glioma

Estramustine, a carbamate ester combining 17 beta-estradiol and nornitrogen mustard, has primarily been employed in the treatment of advanced prostatic carcinoma. However, a significant amount of preclinical investigation has been directed toward estramustine's activity against human malignant glioma. These studies have demonstrated that estramustine has potent antiproliferative effects against malignant glioma both in vitro and in vivo. Similar antimitotic effects also have been demonstrated for other carbamate esters. Estramustine does not impair proliferation of nonneoplastic astrocytes at concentrations that inhibit glioma cells. Although the reasons for this selective activity remain to be determined, it has been shown that malignant gliomas expresses an estramustine-specific binding site, estramustine-binding protein, more than brain tissue. In the clinical situation, an uptake and accumulation of estramustine in human glioma tissue have been demonstrated. Estramustine has been shown to enhance the cytotoxic effects of irradiation in relatively radioresistant glioma cells both in cell culture and in a rat glioma model. Estramustine has been regarded as mainly an anti-mitotic drug but recently other effects such as inhibition of DNA synthesis, induction of apoptosis, and membrane alterations have been shown. This report summarizes the preclinical observations concerning the effects of estramustine and related compounds on human malignant gliomas. These findings form the basis for proposing further laboratory and clinical investigation regarding estramustine and human malignant gliomas.

In vitro inhibition of cell proliferation, viability, and invasiveness in U87MG human glioblastoma cells by estramustine phosphate

OBJECTIVE

Several determinants of cell motility are highly dependent on the cytoskeleton, in particular, microtubules. To our knowledge, there have been no previous reports regarding the anti-invasive ability by an antimicro-tubule agent, estramustine phosphate (EMP), on glioblastoma cell lines. We investigated the modulated cell proliferation and invasiveness by EMP in vitro.

METHODS

We determined the relative survival rate by cell proliferation assay and the percent survival fraction by monotetrazolium assay. Furthermore, an invasion index was used to quantify the migrating and invasive potential of the human glioblastoma cell line, U87MG, in Boiden's chamber with reconstituted basement membrane (Matrigel; Collaborative Research, Lexington, MA).

RESULTS

We found that 0.5 mumol/L EMP had no effect in any of the assays. Concentrations of 1, 5, and 10 mumol/L demonstrated a concentration- and time-dependent depression in all of the assays. A range of drug concentration of EMP, 1 to 10 mumol/L, in which cell invasiveness was successfully inhibited, was comparable with antiproliferative capacity.

CONCLUSION

The data add to the findings that EMP not only offers selective antiproliferative activity against glioblastoma but also reduces invasiveness, consistent with its main mechanism of action. Such findings form the basis for the development of agents that use non-DNA targets for the treatment of glioblastomas and may improve control over tumor proliferation and invasion.

Spontaneous intraventricular hemorrhage caused by lateral ventricular meningioma--case report

A 39-year-old female presented with acute intraventricular hemorrhage manifesting as sudden onset of headache associated with gradually progressing somnolence and left oculomotor nerve paresis. Intraventricular hemorrhage occurred from a meningioma of the lateral ventricle. Computed tomography and magnetic resonance (MR) imaging revealed intraventricular hemorrhage and a mass in the right trigone. The tumor was totally removed. Her postoperative course was uneventful except for left homonymous hemianopia. The histological diagnosis was fibroblastic meningioma. The MR imaging was highly suggestive of hemorrhage from the tumor periphery.

A prospective evaluation of the safety and efficacy of methohexital in the emergency department

A prospective observational study in an inner-city teaching hospital was conducted to evaluate the safety and efficacy of intravenous methohexital (MTX) in the emergency department (ED). Pulse oximetry, vital signs and Glasgow Coma Scale (GCS) scores were recorded serially for 30 minutes after the administration of MTX to 76 adult patients. Likert scales of 1 to 5 were used to record the physician's assessment of the adequacy of sedation and the patient's assessments of recall and pain of the procedure. Patients received an average of 88 +/- 21 mg of MTX for a variety of indications (orthopedic procedures, 78%; sedation for other procedures, 14%; intubation, 5%; and psychiatric interview, 3%). No patient had clinically significant changes in heart rate or blood pressure. Eight (10.5%) had apnea, although only one patient had oxygen saturations of less than 90%. Each episode was brief and easily managed with bag-valve-mask ventilation. Risk factors for apnea included a history of alcoholism (P = .0003) and recent recreational narcotic use (P = .0139). Patients were maximally sedated in an average of 37 +/- 42 seconds. In the subset of initially alert patients, GCS scores decreased from 15 at baseline to 5.9 +/- 4.5. The physician's assessment of the adequacy of sedation was excellent (4.7 +/- 0.7). Patients reported little recall (1.3 +/- 0.9) or pain (1.3 +/- 0.8). It was concluded that MTX caused clinically insignificant changes in hemodynamics or oxygenation, although respiratory depression did occur; significant respiratory depression was brief and easily managed. MTX provided rapid and excellent levels of sedation with little or no patient recall or pain.