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1.
Cryobiology ; 114: 104842, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38158172

RESUMO

In clinical practice, donor hearts are transported on ice prior to transplant and discarded if cold ischemia time exceeds ∼5 h. Methods to extend these preservation times are critically needed, and ideally, this storage time would extend indefinitely, enabling improved donor-to-patient matching, organ utilization, and immune tolerance induction protocols. Previously, we demonstrated successful vitrification and rewarming of whole rat hearts without ice formation by perfusion-loading a cryoprotective agent (CPA) solution prior to vitrification. However, these hearts did not recover any beating even in controls with CPA loading/unloading alone, which points to the chemical toxicity of the cryoprotective solution (VS55 in Euro-Collins carrier solution) as the likely culprit. To address this, we compared the toxicity of another established CPA cocktail (VEG) to VS55 using ex situ rat heart perfusion. The CPA exposure time was 150 min, and the normothermic assessment time was 60 min. Using Celsior as the carrier, we observed partial recovery of function (atria-only beating) for both VS55 and VEG. Upon further analysis, we found that the VEG CPA cocktail resulted in 50 % lower LDH release than VS55 (N = 4, p = 0.017), suggesting VEG has lower toxicity than VS55. Celsior was a better carrier solution than alternatives such as UW, as CPA + Celsior-treated hearts spent less time in cardiac arrest (N = 4, p = 0.029). While we showed substantial improvement in cardiac function after exposure to vitrifiable concentrations of CPA by improving both the CPA and carrier solution formulation, further improvements will be required before we achieve healthy cryopreserved organs for transplant.


Assuntos
Transplante de Coração , Soluções para Preservação de Órgãos , Animais , Ratos , Criopreservação/métodos , Crioprotetores/toxicidade , Transplante de Coração/métodos , Gelo , Soluções para Preservação de Órgãos/farmacologia , Doadores de Tecidos
2.
Aesthetic Plast Surg ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38987314

RESUMO

Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

3.
Aesthetic Plast Surg ; 48(3): 413-439, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37145319

RESUMO

BACKGROUND: Hyaluronidase is used as a reversal agent for hyaluronic acid fillers and to increase the diffusion of other medications after infiltration. Cases of hyaluronidase allergy have been described in the literature since 1984. However, it is still frequently misdiagnosed. This review aims to summarize the current literature to describe the clinical picture of hyaluronidase allergy and identify any risk factors associated with its development, as well as provide recommendations for management in plastic surgery. METHODS: A digital search of PubMed, Scopus, and Embase databases was performed by two reviewers following the PRISMA guidelines. This search identified 247 articles. RESULTS: Two hundred forty-seven articles were identified, and 37 of them met the eligibility criteria. One hundred six patients with a mean age of 54.2 years were included in these studies. History of allergy to other substances (timothy grass, egg white, horse serum, penicillin, insect bites, wasp venom, thimerosal, potassium, histamine, phenylmercuric acetate, and nickel) and allergic diseases (asthma, dermatitis, atopy, rhinitis) was reported. A large portion of the patients with a history of repeated exposure (2-4) experienced the symptoms with their second injection. Nonetheless, there was no significant association between time to allergy development and the number of exposures (P = 0.3). Treatment with steroids +/- antihistamines resulted in the rapid and predominantly complete reversal of the symptoms. CONCLUSIONS: Prior injections or sensitization by insect/wasp venom might be the primary factor associated with hyaluronidase allergy development. The time between the repeated injections is not a likely contributor to the presentation. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Assuntos
Preenchedores Dérmicos , Hipersensibilidade , Humanos , Pessoa de Meia-Idade , Preenchedores Dérmicos/efeitos adversos , Resultado do Tratamento , Hialuronoglucosaminidase , Venenos de Vespas , Fatores de Risco , Ácido Hialurônico/efeitos adversos
4.
Ann Plast Surg ; 86(5): 598-600, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33939655

RESUMO

ABSTRACT: Congenital symmastia is a relatively uncommon condition and poorly described in the literature. Although numerous studies have evaluated iatrogenic symmastia including its prevention and treatment, considerably less has been studied with regard to congenital symmastia. In this review, the authors seek to consolidate the literature published thus far and provide techniques and principles of management that may guide surgeons treating patients with this condition.


Assuntos
Doenças Mamárias , Mamoplastia , Algoritmos , Doenças Mamárias/cirurgia , Humanos
5.
Ann Plast Surg ; 84(4): 409-412, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31923011

RESUMO

INTRODUCTION: Maxillary cancer is relatively rare but devastating for those affected with the disease. For patients who require suprastructural or total maxillectomy for oncologic resection, the resection of the orbital floor can be challenging to reconstruct. The serratus-rib flap is a well-known and useful method of head and neck reconstruction, albeit infrequently used. However, the serratus-rib flap has not previously been described for reconstruction of the orbital floor and has the potential to provide excellent globe support after orbital floor resection in patients after undergoing maxillectomy. METHODS: We retrospectively reviewed all patients who had undergone orbital floor reconstruction using the serratus-rib osteomyofascial free flap by the senior author throughout their career. Surgical technique, postoperative course, complications, and additional required procedures were evaluated. RESULTS: Six patients were found to have undergone the serratus-rib osteomyofascial free flap for orbital floor reconstruction. Average follow-up was 26.7 months from initial surgery. Fifty percent of patients had later minor revision surgery such as fat grafting or scar revision. No patients had any significant complications, and all patients were noted to have good ocular function without diplopia postoperatively. CONCLUSION: The serratus-rib osteomyofascial free flap is an efficacious method for reconstruction of the orbital floor after oncologic resection. Surgeons should consider this flap when performing orbital floor reconstruction, particularly when dead space also needs to be filled with the use of a free flap.


Assuntos
Retalhos de Tecido Biológico , Procedimentos de Cirurgia Plástica , Humanos , Órbita/cirurgia , Estudos Retrospectivos , Costelas
6.
Ann Plast Surg ; 84(5): 608-610, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31663938

RESUMO

Postmastectomy pain syndrome (PMPS) is defined as chronic pain after breast cancer surgery lasting greater than 3 months and has been shown to affect up to 60% of breast cancer patients. Substantial research has been performed to identify risk factors and potential treatment options, although the exact cause of PMPS remains elusive. As breast reconstruction becomes increasingly popular, plastic surgeons are likely to encounter more patients presenting with PMPS. This article summarizes current evidence on risk factors and treatment options for PMPS and highlights further areas of study.


Assuntos
Neoplasias da Mama , Dor Crônica , Mamoplastia , Cirurgiões , Neoplasias da Mama/cirurgia , Humanos , Mastectomia , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/etiologia
7.
J Reconstr Microsurg ; 36(8): 572-576, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32542623

RESUMO

BACKGROUND: The abdomen remains the most preferable donor site for autologous breast reconstruction. Many patients in this population will have had prior abdominal surgery, which is the chief risk factor for having a ventral hernia. While prior studies have examined the impact of prior abdominal surgery on breast reconstruction, limited data exist on the management of patients with a preexisting ventral hernia. The objective of this study was to investigate outcomes of performing ventral hernia repair concurrent with abdominally based microsurgical breast reconstruction. METHODS: A 5-year retrospective review of patients undergoing abdominally based microsurgical breast reconstruction was performed. The experimental group consisted of patients with a preexisting ventral hernia that was repaired at the time of breast reconstruction, and was compared with a historical cohort of patients without preexisting hernias. RESULTS: There were a total of 18 and 225 patients in the experimental and control groups, respectively. There was a higher incidence of prior abdominal surgery in the experimental group (p = 0.0008), but no other differences. Mean follow-up was 20.5 ± 5.2 months. There were no instances of recurrent hernia or flap loss in the experimental group. No significant differences were observed between the experimental and control groups in the incidence of donor-site complications (27.8 vs. 20.9%, respectively; p = 0.55), recipient site complications (27.8 vs. 24.0%, respectively; p = 0.78), operative time (623 ± 114 vs. 598 ± 100 minutes, respectively; p = 0.80), or length of stay (3.4 ± 0.5 vs. 3.1 ± 0.4 days, respectively; p = 0.98). CONCLUSION: Concurrent ventral hernia repair at the time of abdominally based microsurgical breast reconstruction appears to be safe and effective. Larger studies are needed to further define this relationship.


Assuntos
Parede Abdominal , Hérnia Ventral , Mamoplastia , Parede Abdominal/cirurgia , Hérnia Ventral/cirurgia , Herniorrafia , Humanos , Estudos Retrospectivos , Telas Cirúrgicas
8.
Microsurgery ; 39(6): 497-501, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31283856

RESUMO

BACKGROUND: Vascularized lymph node transfer (VLNT) is a well-established method for the surgical management of refractory extremity lymphedema. Generally, donor lymph nodes are harvested from the axilla, groin, or supraclavicular area. However, these sites offer their own disadvantages and introduce risk for inducing lymphedema at the surgical donor site. In our experience, the jejunal mesentery can be an excellent source of lymph nodes without the risk of donor site lymphedema. Long term complications are unknown for this procedure; we report our experience, complication rates, and lessons learned. METHODS: A retrospective review was performed for all patients at our institution undergoing surgical treatment of lymphedema using jejunal mesenteric VLNT from February 2015 to February 2018. Demographic data, length of follow up, and surgical complications were reviewed. RESULTS: Twenty-nine patients have undergone jejunal VLNT at our institution during the three-year study period, with a total of 30 transfers. Five patients had a concurrent omental lymph node transfer. Average length of follow up was 17.6 months (range 1.0-36.8 months). There was one flap loss in this time frame (3.3%). Four patients developed hernias post-operatively (13.8%), and three had nonoperative small bowel obstructions (10.3%). One patient had a postoperative wound infection at the abdominal incision (3.4%). CONCLUSIONS: Jejunal VLNT can be an effective option for surgical treatment of lymphedema, without the risk of postoperative donor site lymphedema. Patients and surgeons should be aware of the risks of hernia and small bowel obstruction with this method compared to other lymph node sources.


Assuntos
Retalhos de Tecido Biológico/transplante , Linfonodos/irrigação sanguínea , Linfonodos/transplante , Linfedema/cirurgia , Microcirurgia/métodos , Complicações Pós-Operatórias/etiologia , Coleta de Tecidos e Órgãos/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Jejuno/cirurgia , Masculino , Mesentério/cirurgia , Pessoa de Meia-Idade , Estudos Retrospectivos
10.
Aesthet Surg J ; 39(4): NP76-NP82, 2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29992227

RESUMO

BACKGROUND: In 2014, the Accreditation Council for Graduate Medical Education (ACGME) increased the minimum required aesthetic surgery cases for graduation from plastic surgery residency from 50 to 150. To date, there has been no research into how this has impacted resident aesthetic surgery training focusing on the resident perception. OBJECTIVES: We sought to evaluate resident perception and satisfaction with their aesthetic surgery training before and after the ACGME case log requirement increase to assess its impact on training and comfort level. METHODS: A survey was administered to all graduating senior residents attending the Senior Residents Conference of the ASPS Annual Meeting in 2014 and 2017. The survey evaluated senior resident aesthetic surgery experience and their confidence and satisfaction with their training. RESULTS: The response rate was 70% in 2014 and 45% in 2017. There was an increase in the number of programs with resident-run cosmetic clinics (14% increase) and designated aesthetic rotations (33% increase) during that time. Resident-run cosmetic clinics were consistently considered the most valuable form of aesthetic training for residents. There also was a substantial increase in the percentage of residents feeling prepared to incorporate aesthetic surgery into their practice after graduation, increasing from 36% to 59% in 2017. The majority of responding residents felt that the ACGME case log requirement increase in 2014 was beneficial for their aesthetic surgery training (68%). CONCLUSIONS: The recent ACGME case log requirement increase for aesthetic surgery training has had a positive effect on resident comfort with aesthetic procedures and their ability to incorporate them into future practice.


Assuntos
Acreditação , Internato e Residência/normas , Procedimentos de Cirurgia Plástica/educação , Cirurgia Plástica/educação , Educação de Pós-Graduação em Medicina/normas , Humanos , Internato e Residência/estatística & dados numéricos , Estudos Longitudinais , Inquéritos e Questionários , Estados Unidos
12.
Ann Plast Surg ; 80(4): 333-338, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29166308

RESUMO

BACKGROUND: Rising contralateral prophylactic mastectomy rates are a subject of national concern. This study assessed (1) factors critical to patients when deciding on contralateral prophylactic mastectomy and (2) patients' quality of life related to concerns about recurrence after unilateral or bilateral breast reconstruction. METHODS: Patients with stage 0 to III breast cancer who underwent unilateral mastectomy or contralateral prophylactic mastectomy and breast reconstruction at a single institution between 2000 and 2012 were identified. Demographic and clinical data were extracted by chart review. Women's fears about breast cancer recurrence were assessed using the Concerns About Recurrence Scale, and motivational factors for contralateral prophylactic mastectomy were identified using the Decisions for Contralateral Prophylactic Mastectomy Survey. RESULTS: Survey responses were received from 157 patients (59%) who underwent unilateral reconstruction and 109 (41%) who underwent bilateral reconstruction. The top 3 reasons for choosing contralateral prophylactic mastectomy were (1) decreasing the risk of contralateral breast disease (97%), (2) peace of mind (96%), and (3) improved survival (93%). Women who chose contralateral prophylactic mastectomy reported significantly greater overall fear and worry compared with the unilateral group, specifically, greater fears of dying and worries about adequately fulfilling roles of daily life (P < 0.05). CONCLUSIONS: Despite no proven survival benefit, women chose contralateral prophylactic mastectomy primarily to optimize oncologic outcomes. Among breast reconstruction patients, women who underwent contralateral prophylactic mastectomy had greater anxiety and overall fear of breast cancer recurrence compared with those who chose unilateral mastectomy. These findings are important to consider when counseling women contemplating contralateral prophylactic mastectomy.


Assuntos
Neoplasias da Mama/psicologia , Neoplasias da Mama/cirurgia , Tomada de Decisões , Recidiva Local de Neoplasia/psicologia , Mastectomia Profilática/psicologia , Adulto , Feminino , Humanos , Mamoplastia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Qualidade de Vida , Estudos Retrospectivos , Inquéritos e Questionários
13.
Radiographics ; 36(7): 2154-2169, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27494386

RESUMO

Frostbite is a localized cold thermal injury that results from tissue freezing. Frostbite injuries can have a substantial effect on long-term limb function and mobility if not promptly evaluated and treated. Imaging plays a critical role in initial evaluation of frostbite injuries and in monitoring response to treatment. A multimodality approach involving radiography, digital subtraction angiography (DSA), and/or multiphase bone scintigraphy with hybrid single photon emission computed tomography (SPECT)/computed tomography (CT) is often necessary for optimal guidance of frostbite care. Radiographs serve as an initial survey of the affected limb and may demonstrate characteristic findings, depending on the time course and severity of injury. DSA is used to evaluate perfusion of affected soft tissues and identify potential targets for therapeutic intervention. Angiography-directed thrombolysis plays an essential role in tissue preservation and salvage in deep frostbite injuries. Multiphase bone scintigraphy with technetium 99m-labeled diphosphonate provides valuable information regarding the status of tissue viability after initial treatment. The addition of SPECT/CT to multiphase bone scintigraphy enables precise anatomic localization of the level and depth of tissue necrosis before its appearance at physical examination and can help uncover subtle findings that may remain occult at scintigraphy alone. Multiphase bone scintigraphy with SPECT/CT is the modality of choice for prognostication and planning of definitive surgical care of affected limbs. Appropriate use of imaging to direct frostbite care can help limit the effects that these injuries have on limb function and mobility. ©RSNA, 2016.


Assuntos
Angiografia Digital/normas , Congelamento das Extremidades/diagnóstico por imagem , Guias de Prática Clínica como Assunto , Radiologia/normas , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único/normas , Tomografia Computadorizada por Raios X/normas , Diagnóstico Diferencial , Humanos , Imagem Multimodal/normas , Traumatismo Múltiplo/diagnóstico por imagem , Osteonecrose/diagnóstico por imagem , Lesões dos Tecidos Moles/diagnóstico por imagem , Estados Unidos
14.
Breast J ; 22(6): 607-615, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27564723

RESUMO

There has been an increasing use of bilateral mastectomy (BM) for breast cancer. We sought to examine our trends among breast conservation (BCT) candidates and women recommended for unilateral mastectomy (UM). Our prospective breast cancer database was queried for women with a first-time, unilateral breast cancer. Patient and histologic factors and surgical treatment, including reconstruction, were evaluated. A detailed chart review was performed among patients from two representative time periods as to the reasons the patient underwent mastectomy. We identified 3,892 women between 2000 and 2012 of whom 60% underwent BCT, 1092 (28%) had UM and 12% underwent BM. BM rose from 4% in 2000 to a high of 19% in 2011, increasing around 2002 for women <40. BCT was less likely with decreasing age (p < 0.0001), lobular histology (p < 0.0001), higher stage (p < 0.0001) and decreasing BMI (p < 0.0001). Among mastectomy patients, contralateral mastectomy was associated with decreasing age (p < 0.0001), Caucasian race (p < 0.0001), and lower stage (p = 0.005). Over time, indications for mastectomy decreased while patients deemed BCT-eligible opting for UM or BM increased dramatically. Increases in the use of BM are in large part among women who were otherwise BCT-eligible. Factors associated with BM use are different for BCT-eligible patients and those recommended for UM. A better understanding of the factors driving individual patient choices is needed.


Assuntos
Neoplasias da Mama/cirurgia , Mastectomia/psicologia , Mastectomia/estatística & dados numéricos , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Carcinoma Lobular/patologia , Carcinoma Lobular/cirurgia , Feminino , Humanos , Mamoplastia/estatística & dados numéricos , Mamoplastia/tendências , Mastectomia/tendências , Mastectomia Segmentar/estatística & dados numéricos , Pessoa de Meia-Idade , Mastectomia Profilática/estatística & dados numéricos , Estudos Prospectivos
17.
Plast Reconstr Surg Glob Open ; 12(4): e5734, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38623441

RESUMO

Background: Reported drug allergies are commonly encountered by surgeons and can lead to uncertainty in selecting an appropriate agent due to concerns of associated risks with related and cross-reactive drugs. This uncertainty can ultimately lead to increased infection rates. Methods: A literature review was conducted in PubMed using a combination of the terms "allergy," "allergic reaction," "anaphylaxis," and "surgery," "surgical," or "operating room" for articles published within the last 10 years. Publications identified with these search terms were then filtered for review articles, sorted by "best match," and a maximum of 100 articles were manually reviewed for each combination of search terms. Results: Search results yielded 46,484 articles, 676 of which were ultimately included for manual review, based on selection criteria. Specifically, articles selected for inclusion focused on surgical allergic reactions that were either related to mechanism of action, causative agent for the allergic reaction, timing of allergic reaction, or recommendations for appropriate management. Conclusions: Allergic reactions can be a common occurrence in the operative room. Knowledge of likely causative agents, timing of a reaction to various agents, and appropriate management in the immediate and delayed setting can improve outcomes and safety for plastic surgery patients.

18.
Plast Reconstr Surg ; 153(3): 754-765, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37199413

RESUMO

BACKGROUND: Medical training is known to impose financial burden on trainees, which has been shown to contribute to burnout, even possibly compromising patient care. Financial literacy allows for management of financial situations affecting professional and personal life. The authors aimed to evaluate the financial status and knowledge among plastic surgery residents. METHODS: A survey regarding finances and financial literacy of plastic surgery residents was sent to all the current accredited U.S. residency programs. The same survey was distributed internally. A descriptive analysis was performed, and multiple Fisher exact tests and a t test evaluated comparisons. RESULTS: Eighty-six residents were included. Most trainees had a student loan (59.3%), with 22.1% having loans more than $300,000. A majority had at least one personal loan debt other than educational (51.1%). Residents with more debt were significantly less likely to pay off their balances monthly. A total of 17.4% of trainees had no plan for how to invest their retirement savings, whereas 55.8% reported not knowing how much they need to save to retire. One in five trainees did not feel prepared to manage personal finances/retirement planning after graduation, a majority had no formal personal finance education in their curriculum, and 89.5% agreed that financial literacy education would be beneficial. Our institutional data largely mirrored national data. CONCLUSIONS: Many residents are lacking in financial knowledge, despite most having significant debt. Additional financial literacy education is needed in plastic surgery training. Curricula development at an institutional or national society level are possible paths toward a coordinated response to this need.


Assuntos
Internato e Residência , Cirurgia Plástica , Humanos , Alfabetização , Renda , Apoio ao Desenvolvimento de Recursos Humanos , Inquéritos e Questionários
19.
Wounds ; 34(2): 43-46, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35801979

RESUMO

INTRODUCTION: Hidradenitis suppurativa can be a debilitating condition, particularly in the pediatric population. Axillary hidradenitis can be particularly challenging because of the risk of scar contracture and limited range of motion after definitive resection and reconstruction. A dermal regeneration template (DRT) and skin grafting have been used to reduce scar contracture in other areas of the body and may benefit this population. OBJECTIVE: This case series retrospectively reviewed and evaluated outcomes using DRT and skin grafting for axillary hidradenitis reconstruction to report the authors' initial experience. MATERIALS AND METHODS: After institutional review board approval, a retrospective review was conducted of a single surgeon's experience for all patients undergoing axillary hidradenitis resection and immediate reconstruction with DRT and skin grafting from 2015 through 2018. Preoperative characteristics, surgical details, and postoperative results were collected. RESULTS: Five patients undergoing 7 procedures were eligible for inclusion. The average age at the time of surgery was 18.2 years. Patients underwent an average of 4.9 negative pressure wound therapy changes prior to skin grafting. No complications, DRT loss, or skin graft loss occurred. All patients were reported to have normal range of motion of the surgically managed extremity after skin grafting. The average follow-up was 273.4 days after the last procedure. As of this writing, no patients had experienced any recurrence of hidradenitis in the surgically managed axilla. CONCLUSIONS: The use of DRT and subsequent skin grafting for the definitive management of axillary hidradenitis resulted in no recurrence and full range of motion of the affected extremity without complications. Surgeons should consider using this method of reconstruction for axillary hidradenitis, particularly in the pediatric population.


Assuntos
Contratura , Hidradenite Supurativa , Procedimentos de Cirurgia Plástica , Axila/cirurgia , Criança , Cicatriz , Contratura/cirurgia , Hidradenite Supurativa/cirurgia , Humanos , Procedimentos de Cirurgia Plástica/métodos , Estudos Retrospectivos , Transplante de Pele
20.
J Org Chem ; 76(7): 2062-71, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21370848

RESUMO

p-Cyclopropylbenzophenone, 20, gives no photoreduction when irradiated in i-PrOH solvent. This is a general phenomenon and a number of cyclopropyl-substituted benzophenones, including 4-(endo-6-bicyclo[3.1.0]hexyl)benzophenone, 19, 4-(cis-2,3-dimethylcyclopropyl)benzophenone, 21, 4-(cis-2-vinylcyclopropyl)benzophenone, 22, and 4-(endo-7-bicyclo[4.1.0]hept-2-enyl)benzophenone, 23, also fail to undergo photoreduction. Instead these latter compounds undergo cis-trans isomerization when irradiated. A mechanism involving formation of an (n, π*) triplet, which subsequently fragments the strained cyclopropane bond to give a lower energy and unreactive open triplet, has been suggested. p-Cyclopropylvalerophenone, 25, and p-(endo-6-bicyclo[3.1.0]hexyl)valerophenone, 24, also undergo photoisomerization and fail to undergo the Norrish Type II photoreactions. Triplet energy dissipation by fragmentation of the cyclopropane bond is also proposed. In addition to the Norrish Type II reaction, p-cyclobutylvalerophenone, 27, undergoes a photofragmentation to give ethylene and p-vinylvalerophenone, 60, by an energy dissipation mechanism involving a 1,4-biradical derived from cyclobutane bond fragmentation.

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