Procedural characteristics and cardiovascular outcomes in patients undergoing drug-coated balloon angioplasty for de novo lesions in large coronary arteries: an observational study.

Limited data exist regarding drug-coated balloon (DCB) treatment in de novo large coronary arteries. We sought to demonstrate procedural characteristics, residual stenosis, and clinical outcomes following DCB angioplasty for de novo lesions in large versus small coronary arteries. The study included 184 consecutive patients with 223 de novo coronary lesions undergoing paclitaxel DCB angioplasty between January 2019 and August 2020, who were divided according to whether the DCB diameter was ≥ 3.0 mm (large group, n = 58) or < 3.0 mm (small group, n = 125). The large group had a higher proportion of acute coronary syndrome more commonly with ostial, bifurcation, and calcified lesions in large vessels and received lesion preparation with more frequent use of scoring or cutting balloons and atherectomy devices compared to the small group. Postprocedural angiographic diameter stenosis was smaller in the large group compared to the small group (31% [22-37] vs. 35% [26-42], p = 0.032), and intravascular ultrasound revealed no significant difference in postprocedural area stenosis between the groups (66.2 ± 7.7% vs. 67.9 ± 7.8%; p = 0.26). The median follow-up duration was 995 days. The incidence of a composite of all-cause death, myocardial infarction, stroke, or target lesion revascularization was similar between the groups (log-rank p = 0.41) and was influenced by the presence of acute coronary syndrome and anemia but not by DCB diameter. The rate of cardiovascular outcomes after DCB treatment was comparable in de novo large and small coronary arteries. Notably, well-planned lesion preparation with intravascular imaging guidance was prevalent in large vessels.

Habitat shift of adult Caligus undulatus (Copepoda: Siphonostomatoida: Caligidae) from host fish to plankton in response to host behavior.

Before 2019, adults of the sea louse Caligus undulatus were reported exclusively in plankton from ocean samples worldwide and were not known to parasitize fish hosts. In 2019, the first instance of this caligid parasitizing a fish host, Japanese sardinella Sardinella zunasi, was reported in the Seto Inland Sea, Japan. The presently reported study aimed to investigate the biology and ecology of adult C. undulatus in plankton communities in the Seto Inland Sea and surrounding waters from March 2020 to November 2021. The occurrence of sea lice in plankton communities was restricted to the period of August-January, mainly between October and December with maximum plankton abundance (10.5 ind. per 1000 m3) recorded on 30 November 2020. All post-naupliar stages of C. undulatus were found on the host fish, and they represented a typical life cycle pattern known for Caligus species. The sex ratios in both planktonic and parasitic adults were not significantly different. The frequency of occurrence of planktonic and parasitic adult females with egg strings was 68 and 46%, respectively. The number of eggs per string was significantly higher in parasitic adult females (mean ± SD: 16.9 ± 8.6) than in planktonic females (10.4 ± 10.8). These data suggest that adult females were detached from their hosts and continued to produce eggs without feeding. Seasonal migration of S. zunasi to brackish water for spawning may result in the detachment of mature caligids from the host and may be effective in protecting the offspring, which are less tolerant of less brackish water.

Embryonic Pericytes Promote Microglial Homeostasis and Their Effects on Neural Progenitors in the Developing Cerebral Cortex.

Multifaceted microglial functions in the developing brain, such as promoting the differentiation of neural progenitors and contributing to the positioning and survival of neurons, have been progressively revealed. Although previous studies have noted the relationship between vascular endothelial cells and microglia in the developing brain, little attention has been given to the importance of pericytes, the mural cells surrounding endothelial cells. In this study, we attempted to dissect the role of pericytes in microglial distribution and function in developing mouse brains. Our immunohistochemical analysis showed that approximately half of the microglia attached to capillaries in the cerebral walls. Notably, a magnified observation of the position of microglia, vascular endothelial cells and pericytes demonstrated that microglia were preferentially associated with pericytes that covered 79.8% of the total capillary surface area. Through in vivo pericyte depletion induced by the intraventricular administration of a neutralizing antibody against platelet-derived growth factor receptor (PDGFR)ß (clone APB5), we found that microglial density was markedly decreased compared with that in control antibody-treated brains because of their low proliferative capacity. Moreover, in vitro coculture of isolated CD11b+ microglia and NG2+PDGFRα- cells, which are mostly composed of pericytes, from parenchymal cells indicated that pericytes promote microglial proliferation via the production of soluble factors. Furthermore, pericyte depletion by APB5 treatment resulted in a failure of microglia to promote the differentiation of neural stem cells into intermediate progenitors. Taken together, our findings suggest that pericytes facilitate microglial homeostasis in the developing brains, thereby indirectly supporting microglial effects on neural progenitors.SIGNIFICANCE STATEMENT This study highlights the novel effect of pericytes on microglia in the developing mouse brain. Through multiple analyses using an in vivo pericyte depletion mouse model and an in vitro coculture study of isolated pericytes and microglia from parenchymal cells, we demonstrated that pericytes contribute to microglial proliferation and support microglia in efficiently promoting the differentiation of neural stem cells into intermediate progenitors. Our present data provide evidence that pericytes function not only in the maintenance of cerebral microcirculation and blood brain barrier (BBB) integrity but also in microglial homeostasis in the developing cerebral walls. These findings will expand our knowledge and help elucidate the mechanism of brain development both in healthy and disease conditions.

Coronavirus Disease 19 (COVID-19) Vaccine Effectiveness Against Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Delta-Dominant and Omicron-Dominant Periods in Japan: A Multicenter Prospective Case-control Study (Factors Associated with SARS-CoV-2 Infection and the Effectiveness of COVID-19 Vaccines Study).

BACKGROUND: Although several coronavirus disease 2019 (COVID-19) vaccines initially showed high efficacy, there have been concerns because of waning immunity and the emergence of variants with immune escape capacity. METHODS: A test-negative design case-control study was conducted in 16 healthcare facilities in Japan during the Delta-dominant period (August-September 2021) and the Omicron-dominant period (January-March 2022). Vaccine effectiveness (VE) against symptomatic severe acute respiratory syndrome coronavirus 2 infection was calculated for 2 doses for the Delta-dominant period and 2 or 3 doses for the Omicron-dominant period compared with unvaccinated individuals. RESULTS: The analysis included 5795 individuals with 2595 (44.8%) cases. Among vaccinees, 2242 (55.8%) received BNT162b2 and 1624 (40.4%) received messenger RNA (mRNA)-1273 at manufacturer-recommended intervals. During the Delta-dominant period, VE was 88% (95% confidence interval [CI], 82-93) 14 days to 3 months after dose 2 and 87% (95% CI, 38-97) 3 to 6 months after dose 2. During the Omicron-dominant period, VE was 56% (95% CI, 37-70) 14 days to 3 months since dose 2, 52% (95% CI, 40-62) 3 to 6 months after dose 2, 49% (95% CI, 34-61) 6+ months after dose 2, and 74% (95% CI, 62-83) 14+ days after dose 3. Restricting to individuals at high risk of severe COVID-19 and additional adjustment for preventive measures (ie, mask wearing/high-risk behaviors) yielded similar estimates, respectively. CONCLUSIONS: In Japan, where most are infection-naïve, and strict prevention measures are maintained regardless of vaccination status, 2-dose mRNA vaccines provided high protection against symptomatic infection during the Delta-dominant period and moderate protection during the Omicron-dominant period. Among individuals who received an mRNA booster dose, VE recovered to a high level.

Chiral Light Amplifier with Pumped Weyl Semimetals.

Parallel electric and magnetic fields applied to Weyl semimetals pump axial charge via the axial anomaly until balanced by intervalley relaxation. The resulting nonequilibrium steady state exhibits the chiral magnetic effect as well as the anomalous Hall effect, which coupled with Maxwell's equations leads to unstable electromagnetic waves at low frequency and long wavelength. Here, we show that such chiral magnetic instability manifests itself as anomalous reflectance of the surface of pumped Weyl semimetal. Depending on electric, chiral magnetic, and anomalous Hall conductivities, the reflectance is found to exceed unity in a finite range of frequency for a circularly polarized light incident along the direction of Weyl node separation.

Impact of prolonged drug-coated balloon inflation on residual stenosis and clinical outcomes in coronary artery disease patients: A propensity score matched analysis.

BACKGROUND: There is a paucity of data regarding the optimal duration of drug-coated balloon (DCB) inflation for coronary lesions. We sought to explore the effect of DCB angioplasty with versus without long inflation time on residual stenosis and clinical outcomes in patients with coronary artery disease. METHODS: This study included 314 consecutive patients with 445 lesions undergoing paclitaxel DCB angioplasty using different inflation time, divided according to whether the total inflation time of the DCB was ≥180 s (prolonged group) or <180 s (standard group). The primary clinical endpoint, defined as a composite of all-cause death, myocardial infarction, stroke, or target lesion revascularization, was examined in 92 propensity score matched pairs. RESULTS: In the matched cohort, the median clinical follow-up period was 947 days. Postprocedural angiographic diameter stenosis was smaller in the prolonged group than in the standard group (30.0% [22.0-37.0] vs. 33.5% [25.5-40.5]; p = 0.042). Intravascular ultrasound measurements revealed that longer DCB inflation time resulted in smaller area stenosis (66.6 ± 7.8% vs. 69.4 ± 7.0%; p = 0.044) and a less mean increase in percent atheroma volume (-11.2 ± 7.1% vs. -7.4 ± 5.9%; p = 0.004) after angioplasty. The rate of the primary endpoint was lower in the prolonged group than in the standard group (log-rank p = 0.025). The efficacy of prolonged DCB inflation was prominent in patients with in-stent restenosis and longer lesions. CONCLUSION: Prolonged DCB inflation was associated with reduced residual stenosis and improved clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention. Prospective randomized trials are warranted to validate the benefits of DCB angioplasty with long inflation time.

In situ temperature-compensated ultraviolet spectrophotometry to estimate nitrate and chloride concentrations in estuarine seawater with different salinity and composition.

Various methods have been proposed for in situ measurement of nitrate concentrations from the ultraviolet (UV) absorbance spectrum of seawater with stable salinity and constituents. However, salinity and temperature affect the UV absorption spectrum of seawater. In sea areas with large variability in salinity and water temperature, accurate nitrate ion concentration measurements remain challenging. We performed in situ measurements of nitrate, chloride, and bromide in estuarine seawater with different salinity compositions and applied water temperature compensation. First, the impact of water temperature on the UV absorbance of chloride, bromide, and nitrate was experimentally investigated and represented in a mathematical model. Next, chloride, bromide, and nitrate concentrations were estimated by suppressing the impact of residual components from the UV absorbance spectra of seawater using principal component regression (PCR). Hence, the chloride, bromide, and nitrate concentrations were determined by measuring the UV absorbance spectrum of seawater alone, without measuring water temperature and electrical conductivity. The proposed method was more accurate (±1.39 µM below 100 µM and ±0.90 µM below 20 µM) than the conventional method (±2.35 µM below 100 µM and ±1.88 µM below 20 µM) and PCR without water temperature compensation (±3.67 µM). In a field study, an in situ UV spectrophotometer with water temperature compensation was used to measure depth profiles of nitrate concentrations in estuarine seawater. We successfully measured the depth profiles of low chloride and high nitrate concentrations in the surface layer as well as high chloride and low nitrate concentrations in the lower layer. The proposed method enables in situ measurements of nitrate concentrations in waters with either stable or highly variable salinity and composition. Unlike conventional chemical analysis, our method can describe detailed spatiotemporal variations in nitrate concentrations.

Bulk Viscosity of Dual Bose and Fermi Gases in One Dimension.

One-dimensional Bose and Fermi gases with contact interactions are known to exhibit the weak-strong duality, where the equilibrium thermodynamic properties of one system at weak coupling are identical to those of the other system at strong coupling. Here, we show that such duality extends beyond the thermodynamics to the frequency-dependent complex bulk viscosity, which is provided by the contact-contact response function. In particular, we confirm that the bulk viscosities of the Bose and Fermi gases agree in the high-temperature limit, where the systematic expansion in terms of fugacity is available at arbitrary coupling. We also compute their bulk viscosities perturbatively in the weak-coupling limit at arbitrary temperature, which via the duality serve as those of the Fermi and Bose gases in the strong-coupling limit.

Minimum detectable change in reaction time to the Posner task due to change in sustained attention.

[Purpose] Spatial attention evaluations are beneficial for patients with unilateral spatial neglect or dementia. Thus, such evaluations are crucial among these patients for determining functional disorder extents. The study aimed to determine minimal detectable changes in reaction time to the Posner task among healthy young participants for establishing spatial attention evaluation protocols. [Participants and Methods] The study recruited 10 healthy young adults (five males and five females; mean age: 28.9 ± 4.0 years). Each participant completed two sessions of the Posner task with 160 trials per session. The reaction time for each trial was measured. Data obtained by the two blocks were analyzed by Bland-Altman analysis, and intraclass correlation coefficient case 1 and minimal detectable changes at the 95% confidence interval were calculated. [Results] Bland-Altman analysis indicated no systematic bias. The intraclass correlation coefficient case 1 exceeded 0.80 under all conditions of the Posner task, whereas the minimal detectable changes at the 95% confidence interval spanned 23-34 ms. [Conclusion] The results exhibited high reliability for reaction time to the Posner task. The minimal detectable changes as the 95% confidence interval values determined in this study based on reaction time can be applied to establish spatial attention evaluation protocols.

Validity of anaerobic threshold measured in resistance exercise.

[Purpose] Intensity for resistance exercise is estimated based on the maximum muscle strength. Exercise prescription without evaluating the biological response has a challenge. This study aimed to confirm whether anaerobic threshold measured using cardiopulmonary exercise test in resistance exercise is appropriate or not. [Participants and Methods] Resistance exercise adopted for the study was right-leg knee extension. The participants were 10 healthy young males. We investigated whether the oxygen uptake kinetics achieved a steady state within 3 min during the constant-load test with knee extension at 80% anaerobic threshold using cardiopulmonary exercise test with knee extension. If oxygen uptake kinetics achieved a steady state within 3 min, the exercise intensity measured using cardiopulmonary exercise test was considered appropriate. [Results] Anaerobic threshold was measured using the conventional approach in all participants. The steady state of oxygen uptake kinetics could be achieved within 3 min. In the constant-load test with knee extension at 80% anaerobic threshold, the oxygen uptake kinetics achieved a steady state within 3 min. [Conclusion] Based on the findings, the anaerobic threshold obtained using cardiopulmonary exercise test with resistance exercise was judged as appropriate. The results of this study contribute to the accurate setting of exercise load for resistance exercise and condition setting for the evaluation of skeletal muscle function.

Relationship between malnutrition and possible sarcopenia in the AWGS 2019 consensus affecting mortality in hemodialysis patients: a prospective cohort study.

BACKGROUND: The first objective of this study was to determine the relationship between muscle strength or physical performance and mortality, and the second objective was to show the relationship of Geriatric Nutritional Risk Index (GNRI) to muscle strength and physical performance decline. METHODS: We examined handgrip, the 5-times chair stand test, and GNRI in 635 maintenance hemodialysis patients and followed up for 72 months. Predictors for all-cause death were examined using Kaplan-Meier analysis and Cox proportional analysis. The relationship between possible sarcopenia and nutritional disorder (GNRI) was constructed receiver operating characteristic (ROC) curve. We used the Youden index to determine the optimal cutoff points for GNRI. RESULTS: The multivariate Cox proportional hazard analysis revealed that the GNRI did not show any significance, although handgrip (HR 3.61, 95% CI 1.70-7.68, p < 0.001) and the 5-times chair stand test (HR 1.71 95% CI 1.01-2.90, p = 0.045) were significant predictors for mortality. On the evaluation of possible sarcopenia by handgrip strength, the area under curve (AUC) on ROC curve analysis were 0.68 (95% CI 0.64-0.72), and 5-chair stand, the AUC on ROC were 0.55 (95% CI 0.51-0.60). The cut-off value for the GNRI discriminating those at possible sarcopenia by handgrip strength based on the Youden index was 91.5. CONCLUSIONS: Our study suggests that the handgrip strength test of the AWGS 2019 sarcopenia consensus was a simple and useful tool to predict mortality in chronic hemodialysis patients. Furthermore, GNRI assessment can be a useful tool for screening before assessing possible sarcopenia when it is difficult to perform SARC-F to all patients.

Association between pulmonary oxygen uptake on-kinetics and acute cardiovascular responses to resistance exercise in patients with coronary artery disease: a preliminary study.

[Purpose] This study aimed to examine whether pulmonary oxygen uptake on-kinetics at the onset of moderate-intensity exercise can predict acute cardiovascular responses to resistance exercise. [Participants and Methods] The association between pulmonary oxygen uptake on-kinetics and acute cardiovascular responses to a single resistance exercise session was investigated in seven patients with low-risk coronary artery disease who underwent revascularization through percutaneous coronary intervention. The participants performed a cardiopulmonary exercise test on a cycle ergometer and a single resistance exercise session at 30% of maximum voluntary contraction on a bilateral leg-extension machine 1 week after surgery. We measured the ventilatory anaerobic threshold and pulmonary oxygen uptake on-kinetics during the cardiopulmonary exercise test; left ventricular ejection fraction at rest; and heart rate, systolic blood pressure, and rate pressure product during the single resistance exercise session. [Results] Pulmonary oxygen uptake on-kinetics showed a positive association with the amount of increase in systolic blood pressure and rate pressure product during the single resistance exercise session, but had no association with the amount of increase in heart rate. Ventilatory anaerobic threshold and left ventricular ejection fraction were not associated with these parameters. [Conclusion] These data suggested that pulmonary oxygen uptake on-kinetics can be a useful evaluation index for predicting acute systolic blood pressure and rate pressure product responses to low-intensity resistance exercise 1 week after percutaneous coronary intervention in patients with low-risk coronary artery disease.

Correction to: Increased prevalence of cerebral microbleeds in patients with low left ventricular systolic function.

In the original publication of the article, under the results section, the following sentence.

Increased prevalence of cerebral microbleeds in patients with low left ventricular systolic function.

Gradient-echo T2-star (T2*)-weighted magnetic resonance imaging (MRI) is a sensitive method to detect cerebral microbleeds (CMBs). The presence of CMBs was reported to be a marker of future cardiovascular mortality and is associated with various cardiovascular risk factors, use of antithrombotic drugs, and cognitive dysfunction. However, the relationship between cardiac function and CMBs remains unclear. We investigated the association between cardiac function and presence of CMBs in patients with cardiovascular diseases. This single-center retrospective study included a total of 424 participants (mean age 70 ± 12 years; men 286 (67%); mean left ventricular ejection fraction (LVEF) 61% ± 12%] who underwent echocardiography and brain T2*-weighted MRI within 1 month without neurologic abnormality. CMBs were found in 118 (28%) patients. There was no significant relationship between CMBs and anticoagulant or antiplatelet therapy. LVEF was significantly lower in patients with CMBs than in those without CMBs (59% ± 13% vs. 62% ± 11%, P < 0.05). On multivariate logistic analysis, lower LVEF [odds ratio (OR) 0.98, 95% confidence interval (CI) 0.96-1.00; P < 0.05] and age (OR 1.02, 95% CI 1.00-1.05; P < 0.05) were significantly associated with CMBs. The presence of CMBs was frequently observed in the patients with cardiovascular disease and was significantly associated with age and LVEF.

Effect of cold oral stimulation on orthostatic hypotension in multiple system atrophy: a case study.

[Purpose] The aim of this case study is to reconsider the method for preventing orthostatic hypotension in multiple system atrophy. [Participant and Methods] The case was that of a 70-year-old female with multiple system atrophy who experienced frequent falls and orthostatic hypotension. An orthostatic test was performed, and the effect of cold oral stimulation before standing was compared with no stimulation. Outcome measures were blood pressure, heart rate variability and autonomic variables. [Results] In the control test, blood pressure decreased from 150/72 mmHg in the supine position to 98/58 mmHg in the standing position. Heart rate increased from 71 bpm to 82 bpm, high frequency declined from 16.48 msec2 to 14.07 msec2, and low/high frequency increased from 2.56 to 5.13. Cold stimulation in the standing position induced changes in blood pressure from 168/82 mmHg to 104/72 mmHg, heart rate from 73 bpm to 83 bpm, high frequency from 61.29 msec2 to 24.56 msec2, and low/high frequency from 1.45 to 6.33 msec2. [Conclusion] Standing after cold stimulation affected autonomic variables, but did not affect the heart rate or blood pressure, possibly because of damaged peripheral blood vessels. Further research is required to demonstrate the effect of cold stimulation on orthostatic hypotension.

Effects of gender and grade on differences in physiotherapy students' interest and reasons for participating in overseas volunteer programs.

[Purpose] The purpose of the present study was to evaluate the gender and grade differences in interest and reasons associated with overseas volunteer participation among physiotherapy students using a cross-sectional survey. [Participants and Methods] The participants were 1,093 physiotherapy students who were enrolled at the International University of Health and Welfare's Ohtawara, Narita, Odawara, and Fukuoka campuses in 2017. A cross-sectional design was used to study the differences between gender and among undergraduate grade levels. The degree of interest and reasons associated with overseas volunteer participation were evaluated by a questionnaire survey using a four-point scale. [Results] Female students were significantly more interested and active in overseas volunteer participation than male students. As for participation by students' grades, significant differences were found in three items only among female students. [Conclusion] Female students were significantly more active at volunteering than male students. It was suggested that we need to encourage students to engage in overseas volunteer participation from the time of admission, especially female students.

Infective endocarditis caused by Capnocytophaga canimorsus; a case report.

BACKGROUND: Capnocytophaga canimorsus is a gram-negative bacterium and an oral commensal in dogs and cats, but occasionally causes serious infections in humans. Septicemia is one of the most fulminant forms, but diagnosis of C. canimorsus infection is often difficult mainly because of its very slow growth. C. canimorsus infective endocarditis (IE) is rare and is poorly understood. Since quite a few strains produce ß-lactamase, antimicrobial susceptibility is pivotal information for adequate treatment. We herein report a case with C. canimorsus IE and the results of drug susceptibility test. CASE PRESENTATION: A 46-year-old man had a dog bite in his left hand 3 months previously. The patient was referred to our hospital for fever (body temperature > 38 °C), visual disturbance, and dyspnea. Echocardiography showed aortic valve regurgitation and vegetation on the leaflets. IE was diagnosed, and we initially administered cefazolin and gentamycin assuming frequently encountered microorganisms and the patient underwent aortic valve replacement. C. canimorsus was detected in the aortic valve lesion and blood cultures. It was also identified by 16S ribosome DNA sequencing. Ceftriaxone were started and continued because disk diffusion test revealed the isolate was negative for ß-lactamase and this case had cerebral symptoms. The patient successfully completed antibiotic treatment following surgery. CONCLUSIONS: We diagnosed C. canimorsus sepsis and IE by extended-period blood cultures and 16S ribosome DNA sequencing by polymerase chain reaction, and successfully identified its drug susceptibility.

Development and validation of a Fall Risk Assessment Index for dialysis patients.

BACKGROUND: Dialysis patients often have low physical performance due to uremic sarcopenia, protein energy wasting (PEW), and incidence intradialytic hypotension (IDH), which are indicated as risk factors for falling. The objective of this study was to develop a symptom-encompassing evaluation form to predict falls with high sensitivity for dialysis patients. METHODS: A total of 251 patients who had been receiving maintenance hemodialysis therapy three times a week were enrolled in the study. Demographics, malnutrition and inflammatory status, dialytic therapeutic management situation, physical function and performance, and inquiries about falling were recorded. The Cox proportional hazards analysis evaluated the impact of falls. Calculated hazard ratios were converted to weighted scores, using approximate multiples of 0.5 and an evaluation form was created, which we called the Dialysis Fall Risk Index (DFRI). Kaplan-Meier survival analyses with the log-rank test and the Cox proportional hazard analysis were performed to evaluate the validity of the DFRI. RESULTS: The DFRI consisted of seven items and a total of 12 points. The predictive validity of DFRI included hazard ratios for quartile 3 and 4 of 2.65 and 3.84, respectively, compared with quartile 1 as a reference point. The cut-off point of the DFRI showed the highest sensitivity and specificity among other screening indices. DISCUSSION: The present study included the development of a new evaluation form that encompasses symptoms of end-stage kidney disease to predict falls in dialysis patients.

Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand.

Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of gem-dichromiomethane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive gem-dimetalloalkane species. The isolated gem-dichromiomethane complex acted as a storable silylmethylidene carbene equivalent, with reactivity that could be changed dramatically upon addition of a Lewis acid (ZnCl2) and a base (TMEDA) to promote both silylalkylidenation of polar aldehydes and silylcyclopropanation of nonpolar alkenes. Identification of a key reactive species also identified the catalytic version of these transformations and provided insights into the reaction mechanism. In contrast to Simmons-Smith cyclopropanation, the real reactive species for the current cyclopropanation was a chromiocarbene species, not a chromium carbenoid species.