Wake-up ischemic stroke associated with short sleep duration and sleep behavior: A stratified analysis according to risk of obstructive sleep apnea.

OBJECTIVE: Wake-up stroke (WUS) is an ischemic stroke occurring during nocturnal sleep with neurological deficits observed upon awakening. Our study aimed to investigate the association between WUS, sleep curtailment, and sleep behavior according to the obstructive sleep apnea (OSA) risk in patients with acute ischemic stroke. METHODS: This single-centered, retrospective study included hospitalized subjects with acute ischemic stroke occurring within 30 days. A total of 250 participants were classified as WUS or not and enquired about their sleep habits concerning sleep time on weekdays and weekends, demographic factors, and assessed comorbid medical conditions. Weekend catch-up sleep (CUS) was defined as the extension of sleep duration during weekends. The average weekly sleep duration and chronotype were assessed. The association between WUS and sleep factors was analyzed. RESULTS: WUS was observed in 70 patients (28.0%) with acute ischemic stroke. There were no significant differences in the demographic and stroke-related variables between the WUS and non-WUS (NWUS) groups. Upon stratified analysis based on risk of OSA, average weekly sleep duration (odds ratio, [OR] = 0.60, 95% confidence interval, [CI] = 0.41-0.89; p = 0.011), the presence of weekend CUS (OR = 0.07, 95% CI = 0.01-0.97; p = 0.047), and chronotype (OR = 0.62, 95% CI = 0.39-0.98; p = 0.041) were independently associated with WUS in low-risk group with OSA, but not in the high-risk group. CONCLUSIONS: Short sleep duration and lack of compensation are significantly associated with WUS in low-risk OSA group. Insufficient sleep and sleep behaviors could play a different role in causing ischemic stroke during sleep when patients are stratified by their risk of sleep apnea.

Quantitative electroencephalographic analysis of delirium tremens development following alcohol-withdrawal seizure based on a small number of male cases.

INTRODUCTION: Seizures and delirium tremens (DTs) are recognized as severe alcohol-withdrawal symptoms. Prolonged admission and serious complications associated with alcohol withdrawal are responsible for increased costs and use of medical and social resources. This study investigated the predictive value of quantitative electroencephalography (QEEG) for developing alcohol-related DTs after alcohol-withdrawal seizure (AWS). METHODS: We compared differences in QEEG in patients after AWS (n = 13). QEEG was performed in the intensive care unit within 48 h of admission, including in age- and sex-matched healthy controls. We also investigated the prognostic value of QEEG for the development of alcohol DTs after AWS in a retrospective, case-control study. The spectral power of each band frequency and the ratio of the theta to alpha band (TAR) in the electroencephalogram were analyzed using iSyncBrain® (iMediSync, Inc., Korea). RESULTS: The beta frequency and the alpha frequency band power were significantly higher and lower, respectively, in patients than in age- and sex-matched healthy controls. In AWS patients with DTs, the relative beta-3 power was lower, particularly in the left frontal area, and the TAR was significantly higher in the central channel than in those without DTs. CONCLUSION: Quantitative EEG showed neuronal excitability and decreased cognitive activities characteristic of AWS associated with alcohol-withdrawal state, and we demonstrated that quantitative EEG might be a helpful tool for detecting patients at a high risk of developing DTs during an alcohol-dependence period.

Real-world experience with 240 mg of galcanezumab for the preventive treatment of cluster headache.

BACKGROUND: Galcanezumab of 300 mg monthly is the FDA approved preventive medication for cluster headache (CH) during the cluster period. Compared to the 120 mg galcanezumab syringe for the treatment of migraines, the 100 mg syringe for CH has globally not been as widely available. The aim of our study was to investigate the preventive efficacy and tolerability of two 120 mg galcanezumab doses for episodic CH in clinical practices. METHODS: We evaluated patients with CH who received at least 1 dose of 240 mg (2 prefilled syringe of 120 mg) of galcanezumab in the 3 university hospitals from February 2020 to September 2021. In the patients with episodic CH, the efficacy and safety data of galcanezumab were analyzed regarding to the presence of the conventional preventive therapy at the timing of therapy of galcanezumab. The data of other subtypes of CH were separately described. RESULTS: In 47 patients with episodic CH, galcanezumab was started median 18 days after the onset of current bout (range 1-62 days) and 4 patients (10.8%) received second dose of galcanezumab. The median time to the first occurrence of 100% reduction from baseline in CH attacks per week after galcanezumab therapy was 17 days (25% to 75% quartile range: 5.0 ~ 29.5) in all patients with episodic CH, 15.5 days (3.8 ~ 22.1) in 36 patients with galcanezumab therapy add-on conventional preventive therapy, 21.0 days (12.0 ~ 31.5) in 11 patients started galcanezumab as initial preventive therapy. Among 33 patients with headache diary, the proportion of patients with 50% or more reduction in weekly CH attacks at week 3 from baseline were 78.8%. There was no significant difference in the proportion of patients with a reduction of at least 50% in weekly frequency of CH attacks at week 3 between 24 patients received galcanezumab therapy add-on conventional preventive therapy and 9 patient who received initial galcanezumab therapy. (83.3%, vs 66.7%, p = 0.36). There were no significant differences in proportion of "very much better or "much better" between 36 patients received galcanezumab therapy add-on conventional preventive therapy and 11 patient who received initial GT (86.1%, vs 63.6%, p = 0.18). CONCLUSION: One 240 mg dose of galcanezumab with/without conventional therapy for the prevention of CH is considered effective and safe in clinical practices, as seen in the clinical trial of galcanezumab.

Oxygen Therapy in Cluster Headache, Migraine, and Other Headache Disorders.

Oxygen therapy (OT) can relieve head pain in certain primary headache disorders, including cluster headache (CH). The exact underlying mechanism is currently uncertain, but suggested mechanisms include inhibition of the trigeminoautonomic reflex, modulation of neurotransmitters, and cerebral vasoconstriction. OT is the standard for acute treatment of CH, but patients with CH often experience considerable difficulties accessing home OT due to problems with insurance coverage. Inhalation of 100% oxygen at 6-12 L/min for 15-30 min using a non-rebreather face mask is one of the most effective acute therapies for CH, but several trials have indicated the superiority of higher oxygen flow rates of up to 15 L/min and/or using a demand-valve oxygen mask that can produce very high flow rates. Two randomized controlled trials have demonstrated the efficacy of OT in migraine, but obtaining reliable evidence is considered difficult because of different inhalation protocols, varying outcome measures, and small samples. There are some reports on the efficacy of OT as an adjuvant therapy in hypnic headache, primary headache in the emergency department, and even postdural puncture headache. The goal of this review article is to expand the knowledge regarding the use of oxygen in the treatment of headache disorders.

Myelin Oligodendrocyte Glycoprotein-Immunoglobulin G in the CSF: Clinical Implication of Testing and Association With Disability.

BACKGROUND AND OBJECTIVE: To investigate the clinical relevance of CSF myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) testing in a large multicenter cohort. METHODS: In this multicenter cohort study, paired serum-CSF samples from 474 patients with suspected inflammatory demyelinating disease (IDD) from 11 referral hospitals were included. After serum screening, patients were grouped into seropositive myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD, 31), aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG + NMOSD, 60), other IDDs (217), multiple sclerosis (MS, 45), and non-IDDs (121). We then screened CSF for MOG-IgG and compared the clinical and serologic characteristics of patients uniquely positive for MOG-IgG in the CSF to seropositive patients with MOGAD. RESULTS: Nineteen patients with seropositive MOGAD (61.3%), 9 with other IDDs (CSF MOG + IDD, 4.1%), 4 with MS (8.9%), but none with AQP4-IgG + NMOSD nor with non-IDDs tested positive in the CSF for MOG-IgG. The clinical, pathologic, and prognostic features of patients uniquely positive for CSF MOG-IgG, with a non-MS phenotype, were comparable with those of seropositive MOGAD. Intrathecal MOG-IgG synthesis, observed from the onset of disease, was shown in 12 patients: 4 of 28 who were seropositive and 8 who were uniquely CSF positive, all of whom had involvement of either brain or spinal cord. Both CSF MOG-IgG titer and corrected CSF/serum MOG-IgG index, but not serum MOG-IgG titer, were associated with disability, CSF pleocytosis, and level of CSF proteins. DISCUSSION: CSF MOG-IgG is found in IDD other than MS and also in MS. In IDD other than MS, the CSF MOG-IgG positivity can support the diagnosis of MOGAD. The synthesis of MOG-IgG in the CNS of patients with MOGAD can be detected from the onset of the disease and is associated with the severity of the disease. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that the presence of CSF MOG-IgG can improve the diagnosis of MOGAD in the absence of an MS phenotype, and intrathecal synthesis of MOG-IgG was associated with increased disability.

Predicting Functional Outcome Based on Linked Data After Acute Ischemic Stroke: S-SMART Score.

Prediction of outcome after stroke may help clinicians provide effective management and plan long-term care. We aimed to develop and validate a score for predicting good functional outcome available for hospitals after ischemic stroke using linked data. A total of 22,005 patients with acute ischemic stroke from the Clinical Research Center for Stroke Registry between July 2007 and December 2014 were included in the derivation group. We assessed functional outcomes using a modified Rankin scale (mRS) score at 3 months after ischemic stroke. We identified predictors related to good 3-month outcome (mRS score ≤ 2) and developed a score. External validations (geographic and temporal validations) of the developed model were performed. The prediction model performance was assessed using the area under the receiver operating characteristic curve (AUC) and the calibration test. Stroke severity, sex, stroke mechanism, age, pre-stroke mRS, and thrombolysis/thrombectomy treatment were identified as predictors for 3-month good functional outcomes in the S-SMART score (total 34 points). Patients with higher S-SMART scores had an increased likelihood of a good outcome. The AUC of the prediction score was 0.805 (0.798-0.811) in the derivation group and 0.812 (0.795-0.830) in the geographic validation group for good functional outcome. The AUC of the model was 0.812 (0.771-0.854) for the temporal validation group. Moreover, they had good calibration. The S-SMART score is a valid and useful tool to predict good functional outcome following ischemic stroke. This prediction model may assist in the estimation of outcomes to determine care plans after stroke.

Characteristics and management of stroke in Korea: 2014-2018 data from Korean Stroke Registry.

BACKGROUND: Lifestyle changes and evolving healthcare practices in Korea have influenced disease patterns and medical care. Since strokes have high disease burden in countries with aging populations, it is necessary to evaluate the associated recent disease characteristics and patient care patterns. The Korean Stroke Registry is a nationwide, multicenter, prospective, hospital-based stroke registry in Korea used to monitor these changes across the population. AIMS: We aimed to evaluate the recent status of clinical characteristics and management of stroke cases in order to identify changes in the Korean population across time. METHODS: This study used Korean Stroke Registry data from patients experiencing ischemic stroke or transient ischemic attack patients, between 2014 and 2018. We analyzed data on demographics, risk factors, stroke subtypes, and treatments that included thrombolysis. RESULTS: A total of 39,291 patients (mean age 68.0 ± 13.0, 58.3% male) were analyzed. The proportions of hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, and prior stroke were 63.4%, 30.9%, 27.7%, 19.4%, and 17.1%, respectively. In the stroke subtype analysis, the frequency of large artery atherosclerosis was highest (32.6%), followed by cardioembolism (21.3%) and small vessel occlusion (19.9%). Acute reperfusion therapy was conducted in 15.3% of cases (11.7% using intravenous tPA and 7.3% using intra-arterial thrombectomy). Intra-arterial thrombectomy also demonstrated a steep increasing trend over time (RR 1.095 (1.060-1.131), p < 0.001). CONCLUSIONS: This study provided analysis of nationwide, hospital-based, quality-controlled data from the Korean Stroke Registry database regarding changes in the characteristics, risk factors, and treatments of strokes in Korea.

Temporal changes in the neutrophil to lymphocyte ratio and the neurological progression in cryptogenic stroke with active cancer.

BACKGROUND: Ischemic stroke patients with active cancer frequently experience early neurological deterioration (END); however, the predictors of END are not well studied. The neutrophil to lymphocyte ratio (NLR) has recently been described as a predictor of poor outcomes in cancer and stroke. However, its role in cancer-related stroke has not been addressed. AIM: We aimed to evaluate the association between the NLR and END in cancer-related stroke patients. METHODS: We included 85 cryptogenic stroke patients with active cancer. END was defined as an increase ≥ 4 on the total National Institutes of Health Stroke Scale (NIHSS) score within 72 hours of admission. The NLR was calculated as the ratio of the absolute neutrophil count to the absolute lymphocyte count. We obtained the NLR during the following three periods: at admission, 1-3 days after admission (D 1-3 NLR) and 4-7 days after admission (D 4-7 NLR). RESULTS: END occurred in 15 (18%) of the 85 patients. END was significantly associated with the initial NIHSS score, infarction volume, and the D 1-3 NLR. In multivariate analysis, a higher D 1-3 NLR, measured before END events, remained an independent predictor of END [adjusted odds ratio = 2.78, 95% confidence interval = 1.09-7.08, P = 0.032]. In terms of temporal changes in the NLR, the END group showed a tendency toward temporal increase in the NLR at D 1-3 (P = 0.061) with subsequent decrements in the D 4-7 NLR (P = 0.088), while the non-END group showed no significant changes in the NLR between periods. CONCLUSIONS: This study demonstrated that a higher NLR could predict END events in cryptogenic stroke patients with active cancer. However, the results should be confirmed in further large prospective studies.

Building Linked Big Data for Stroke in Korea: Linkage of Stroke Registry and National Health Insurance Claims Data.

BACKGROUND: Linkage of public healthcare data is useful in stroke research because patients may visit different sectors of the health system before, during, and after stroke. Therefore, we aimed to establish high-quality big data on stroke in Korea by linking acute stroke registry and national health claim databases. METHODS: Acute stroke patients (n = 65,311) with claim data suitable for linkage were included in the Clinical Research Center for Stroke (CRCS) registry during 2006-2014. We linked the CRCS registry with national health claim databases in the Health Insurance Review and Assessment Service (HIRA). Linkage was performed using 6 common variables: birth date, gender, provider identification, receiving year and number, and statement serial number in the benefit claim statement. For matched records, linkage accuracy was evaluated using differences between hospital visiting date in the CRCS registry and the commencement date for health insurance care in HIRA. RESULTS: Of 65,311 CRCS cases, 64,634 were matched to HIRA cases (match rate, 99.0%). The proportion of true matches was 94.4% (n = 61,017) in the matched data. Among true matches (mean age 66.4 years; men 58.4%), the median National Institutes of Health Stroke Scale score was 3 (interquartile range 1-7). When comparing baseline characteristics between true matches and false matches, no substantial difference was observed for any variable. CONCLUSION: We could establish big data on stroke by linking CRCS registry and HIRA records, using claims data without personal identifiers. We plan to conduct national stroke research and improve stroke care using the linked big database.

Acute Ischemic Stroke Mimicking Non-Convulsive Status Epilepticus.

Status epilepticus and stroke are occasionally characterized by indistinguishable symptoms. Diffusion-weighted imaging (DWI) could not only help differentiating seizure from stroke, but also assist in localizing a focus of seizure and reflect resolution of seizure. We report a case of non-convulsive status epilepticus that presented as acute ischemic stroke, mimicking the latter's clinical manifestations. A 77-year-old right-handed man visited the emergency room with complaints of impaired awareness and fluency with right hemiparesis. Moreover, he presented with first-onset focal to bilateral tonic-clonic seizure with eyeball deviation to the right for 1 minute. Magnetic resonance imaging showed hyperintensity on DWI with a reduced apparent diffusion coefficient (ADC) value in the left pulvinar and left temporo-occipital areas. However, eyeball deviation to the right was not matched with left hemispheric stroke. Electroencephalography (EEG) confirmed ictal discharges in the left temporal area, which were compatible with impaired awareness, ictal aphasia, and eyeball deviation to the right. In cases of conflicting results from neurological examination and DWI/ADC findings, clinicians should consider employing EEG for diagnosing and treating non-convulsive status epilepticus.

Nocturnal Desaturation is Associated With Neurological Deterioration Following Ischemic Stroke: A Retrospective Observational Study.

STUDY OBJECTIVES: The mechanism of early neurological deterioration (END) in patients with stroke remains unclear. We assessed the relationship between nocturnal oxygen desaturation (NOD) in the stroke unit (SU) and END, especially occurring at nighttime, following acute stroke. METHODS: A retrospective analysis was performed on a total of 276 patients with ischemic stroke who were admitted to the SU between July 2013 and June 2015. The oxygen desaturation index was calculated from pulse oximetry data sampled every 1 minute during 9 hours on the first night (10:00 PM to 7:00 AM) after admission, and NOD was defined as oxygen desaturation index ≥ 5 events/h. END was defined as an increase of ≥ 2 points from the baseline National Institutes of Health Stroke Scale during 7 days after onset. We compared clinical characteristics and NOD between patients with and without END. RESULTS: Among the included patients (mean age 69.2; male 55.4%), 42 patients (15.2%) experienced END. The proportion of NOD was significantly greater in the END group (45.2% versus 12.8%, P < .001). After adjusting for confounders, NOD was independently associated with END (odds ratio 7.57; 95% confidence interval 3.14-18.27). Among END patients, 47.6% patients (n = 20) had END during nighttime. Moreover, NOD was more frequent in patients with END during nighttime compared to those with END during daytime (73.7% versus 26.1%, P = .002). CONCLUSIONS: NOD in the SU was associated with END, especially during nighttime, after ischemic stroke. This suggests that treatment of sleep-disordered breathing could be a modifiable factor to possibly reduce the risk of neurological worsening among acute stroke patients.

Predictors of 30-day mortality and the risk of recurrent systemic thromboembolism in cancer patients suffering acute ischemic stroke.

BACKGROUND: Stroke in cancer patients is not rare but is a devastating event with high mortality. However, the predictors of mortality in stroke patients with cancer have not been well addressed. D-dimer could be a useful predictor because it can reflect both thromboembolic events and advanced stages of cancer. AIM: In this study, we evaluate the possibility of D-dimer as a predictor of 30-day mortality in stroke patients with active cancer. METHODS: We included 210 ischemic stroke patients with active cancer. The 30-day mortality data were collected by reviewing medical records. We also collected follow-up D-dimer levels in 106 (50%) participants to evaluate the effects of treatment response on D-dimer levels. RESULTS: Of the 210 participants, 30-day mortality occurred in 28 (13%) patients. Higher initial NIHSS scores, D-dimer levels, and CRP levels as well as frequent cryptogenic mechanism, systemic metastasis, multiple vascular territory lesion, hemorrhagic transformation, and larger infarct volume were related to 30-day mortality. In the multivariate analysis, D-dimer [adjusted OR (aOR) = 2.19; 95% CI, 1.46-3.28, P < 0.001] predicted 30-day mortality after adjusting for confounders. The initial NIHSS score (aOR = 1.07; 95% CI, 1.00-1.14, P = 0.043) and hemorrhagic transformation (aOR = 3.02; 95% CI, 1.10-8.29, P = 0.032) were also significant independent of D-dimer levels. In the analysis of D-dimer changes after treatment, the mortality group showed no significant decrease in D-dimer levels, despite treatment, while the survivor group showed the opposite response. CONCLUSIONS: D-dimer levels may predict 30-day mortality in acute ischemic stroke patients with active cancer.

Cystatin C is a useful predictor of early neurological deterioration following ischaemic stroke in elderly patients with normal renal function.

INTRODUCTION: Cystatin C has been suggested as a sensitive marker of renal function. A high level of cystatin C is related to cardiovascular disease and stroke in elderly patients. We investigated the relationship between levels of cystatin C and early neurological deterioration with acute ischaemic stroke in elderly patients without chronic kidney disease. PATIENTS AND METHODS: We evaluated a total of 771 elderly patients (mean age, 72.2; male, 59.0%) without chronic kidney disease who were admitted following acute ischaemic stroke between March 2010 and January 2015. The patients were divided into four groups based on the quartiles of serum cystatin C values. Early neurological deterioration was defined as an increase of ≥2 points from the baseline National Institutes of Health Stroke Scale score during the 7 days following onset. We compared the clinical characteristics and cystatin C concentrations between patients with and without early neurological deterioration. RESULTS: Eighty-six patients (11.2%) experienced early neurological deterioration. The percentage values of the higher (third and fourth) quartiles were significantly higher in the early neurological deterioration group (30.2% vs. 24.4% and 34.9% vs. 23.8%, P = 0.002). After adjustment for covariates, higher cystatin C levels were independently associated with a higher risk of early neurological deterioration: odds ratio (95% confidence interval) for second quartile 1.59 (0.70-3.58), third quartile 2.75 (1.25-6.04), fourth quartile 3.12 (1.36-7.16); P for trend 0.026. DISCUSSION AND CONCLUSIONS: This study demonstrated that cystatin C concentrations in elderly patients without chronic kidney disease were associated with early neurological deterioration following acute stroke. This suggests that cystatin C level could be a useful predictor for early neurological deterioration following acute stroke.

Nocturnal Desaturation in the Stroke Unit Is Associated With Wake-Up Ischemic Stroke.

BACKGROUND AND PURPOSE: Wake-up stroke (WUS) represents a quarter of all ischemic strokes and may be a specific subgroup. Nocturnal desaturation secondary to sleep-disordered breathing is an independent risk factor for stroke, but the association between nocturnal desaturation and WUS remains unclear. We investigated the relationship between nocturnal desaturation using oxygen desaturation index and WUS in patients with acute stroke in the stroke unit. METHODS: A total of 298 patients admitted for acute ischemic stroke to the stroke unit between July 2013 and May 2015 were enrolled. The oxygen desaturation index was calculated using pulse oximetry data sampled every 1 minute during 9 hours on the first night (10:00 pm-7:00 am) of the stroke unit admission, and nocturnal desaturation was defined as an oxygen desaturation index of 5 at least per hour. We compared the clinical characteristics and nocturnal desaturations between patients with and without WUS. RESULTS: Among all patients (age, 67.7±12.6 years; male, 54.4%), 26.5% patients had WUS. The proportion of nocturnal desaturation was significantly greater in patients admitted with WUS (29.1% versus 12.3%, P=0.001). The age, sex, risk factors except for hyperlipidemia, stroke severity, and stroke mechanisms were similar between the 2 groups. After adjustment for covariates, it was found that nocturnal desaturation was significantly more common in the WUS group (odds ratio, 3.25; 95% confidence interval, 1.63-6.46). CONCLUSIONS: Nocturnal desaturation was more frequently observed in patients admitted with WUS during the first night in the stroke unit. This suggests that nocturnal desaturation is a possible modifiable risk factor for the occurrence of WUS.

Visualization of the degradation of a disulfide polymer, linear poly(ethylenimine sulfide), for gene delivery.

Polyethylenimine (PEI) shows high transfection efficiency and cytoxicity due to its high amine density. The new disulfide cationic polymer, linear poly(ethylenimine sulfide) (l-PEIS), was synthesized for efficient and safe gene delivery. As the amine density of l-PEIS increased, the transfection efficiency also increased. l-PEIS-6 and l-PEIS-8 show transfection efficiencies that are similar to that of PEI. However, cytotoxicity of l-PEIS was not observed due to the biodegradable disulfide bond. The disulfide bonds are stable in the oxidative extracellular condition and can be degraded rapidly in the reductive intracellular condition. The degradation of l-PEIS in HeLa cells was visualized by fluorescence microscopy using the probe-probe dequenching effect of BODIPY-FL fluorescence dye. l-PEIS was degraded completely within 3 h.

Poly(ethylene oxide sulfide): new poly(ethylene glycol) derivatives degradable in reductive conditions.

Poly(ethylene oxide sulfide) (PEOS), polymers consisting of an internal ethylene oxide oligomer and disulfide linkage, were synthesized and characterized. The degree of polymerization was dependent upon temperature, dimethyl sulfoxide condition, and monomer hydrophobicity. The stability of PEOS was measured by the size exclusion chromatography method after the incubation both with and without 5 mM glutathione. The disulfide bond was stable in the extracellular condition but completely degraded in 2 h in the reductive cytosolic condition. Hydrophilic PEOS polymers showed no cytotoxicity on the HepG2 cell line. On the basis of these properties, PEOS can be applied in many drug delivery fields.

New cationic lipids for gene transfer with high efficiency and low toxicity: T-shape cholesterol ester derivatives.

New degradable cationic ester lipids with 'T-shape' configurations were synthesized and tested for gene delivery carrier. Their transfection efficiency and toxicity were compared with commercially available cationic lipids, DOTMA, DOSPA, and DC-Chol. They showed efficient transfection activity and almost no toxicity on mammalian cell lines. Their ester bond degradation was monitored by (1)H NMR.