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1.
Surgeon ; 22(2): 88-91, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37923667

RESUMO

BACKGROUND: Many ENT day-case procedures are performed on otherwise healthy individuals in employment. We hypothesised patients' type of employment may affect the amount of time taken off work following such procedures. We aimed to disprove the hypothesis that there is no difference in time taken off between employees and self-employed individuals. MATERIALS AND METHODS: We prospectively collected data on working adult patients undertaking elective day-case procedures at our department. Collected information included basic patient demographics and type of employment. A telephone call was made to collect data on actual period of time taken off work, 5-6 weeks later. RESULTS: 23% of patients were self-employed, the rest were employees. 92% of self-employed patients received no pay during their time off. This compared with 10% of employed patients receiving no pay. 77% of employed patients received full pay. Although mean time taken off work was less if the patient was self-employed (9.5 days vs 10.63), this was not found to be statistically significant. DISCUSSION AND CONCLUSION: Our study demonstrates time off work following day-case ENT procedures places a higher financial burden on self-employed patients. This should inform patient counselling prior to operations. We demonstrated no statistically significant difference in time off work post-surgery between the 2 groups. There was a possible trend towards less time off in self-employed individuals and we speculate that further research with more patients may demonstrate a statistically significant difference in time off work. Perhaps most importantly is for doctors to consider how long an individual needs off after a given procedure, after taking account of their individual patient needs, rather than defaulting to a standard 2-weeks.


Assuntos
Emprego , Médicos , Adulto , Humanos , Fatores de Tempo , Licença Médica , Procedimentos Cirúrgicos Ambulatórios
2.
Clin Otolaryngol ; 45(1): 83-98, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31670912

RESUMO

OBJECTIVES: The roles of Allied Health Care Professionals (AHPs) in Head and Neck Cancer (HNC) are wide ranging but not clearly defined. Inter-regional variability in practice results from a lack of standardisation in approaches to the Multidisciplinary Team (MDT) make-up and structure. Traditionally, the follow-up of HNC patients is clinician led with multiple scheduled follow-up appointments. The increasing population of HNC patients provides logistical, monetary and efficiency challenges. This systematic review presents the roles of the multiple AHP sub-groups in HNC with the aim of presenting how their differing skill sets can be integrated to modernise our approach in follow-up. DESIGN: We searched MEDLINE, Embase, the Cochrane Library, NIHR Dissemination Centre, The Kings Fund Library, Clinical Evidence, National Health Service Evidence and the National Institute of Clinical Excellence to identify multiple subgroups of AHPs (Dentists, Speech and Language Therapists, Dieticians, Physiotherapists, Psychologists, Clinical Nurse Specialists) and evidence of their role in HNC follow-up. Evidence not directly relating to HNC follow-up was excluded. SETTING AND PARTICIPANTS: This Systematic Review was undertaken online by the Integrate (UK ENT Trainee National Collaborative) Head and Neck Subcommittee. MAIN OUTCOME MEASURES: Most evidence was of low-quality, and the broad nature of the protocol provided a wide variety of study models. Two authors screened the articles for relevance to the topic before final analysis. RESULTS: The main role identified was improvement in Quality of Life and symptom control rather than detecting recurrence. We also demonstrate that it is possible to stratify HNC follow-up patients using their received treatment modality and Distress Thermometers to identify groups who will require more intensive AHP input. CONCLUSIONS: HNC follow-up covers a broad group of patients with differing needs. As such, a blanket approach to this phase of treatment is likely to be less effective than a patient-led model where the group of AHPs are employed on a needs basis rather than at set time points. This will likely lead to greater patient satisfaction, earlier detection of recurrence and efficiency savings.


Assuntos
Neoplasias de Cabeça e Pescoço/diagnóstico , Pessoal de Saúde/normas , Satisfação do Paciente , Qualidade de Vida , Humanos
4.
Can J Urol ; 23(2): 8220-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27085827

RESUMO

INTRODUCTION: The treatment of bilateral renal and/or ureteric stones can be challenging due to concerns about its safety and efficacy compared to staged ureteroscopy. This review evaluates the current evidence to look at the outcomes of bilateral simultaneous ureteroscopy (BS-URS) for urinary stone disease. MATERIALS AND METHODS: A systematic review using studies identified by a literature search between January 1990 and August 2013. All English language articles reporting on outcomes of BS-URS for urolithiasis were included. Two reviewers independently extracted the data from each study. RESULTS: A total of seven studies (312 patients) were identified with a mean age of 40 years. Of the reported stone location, two thirds of the stones were in the ureter. With a mean operative time of 58 minutes, stone free status was achieved in 87.1% after the first look and 91.6% after a re-look for pure ureteric stones. Nearly 86% of patients had a postoperative stent inserted with a mean hospital stay of 2 days. In the pure ureteric stone cohort a total of 134 (50.8%) complications were reported. Around three quarters of the complications were Clavien I grading (hematuria, lower urinary symptoms and flank pain) and under a quarter were Clavien III complications. CONCLUSION: Although BS-URS achieved a high overall stone free rate; the complication rate seemed to be high. The quality of included studies in this review was weak and future research with good methodology is required to evaluate the feasibility and safety of BS-URS procedure.


Assuntos
Terapia a Laser/métodos , Ureteroscopia/métodos , Cálculos Urinários/cirurgia , Humanos , Duração da Cirurgia
5.
BJU Int ; 115(6): 867-73, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25203925

RESUMO

The aim of the present review was to look at the role of ureteroscopy (URS) for treatment of paediatric stone disease. We conducted a systematic review using studies identified by a literature search between January 1990 and May 2013. All English-language articles reporting on a minimum of 50 patients aged ≤ 18 years treated with URS for stone disease were included. Two reviewers independently extracted the data from each study. A total of 14 studies (1718 procedures) were reported in patients with a mean (range) age of 7.8 (0.25-18.0) years. The mean (range) stone burden was 9.8 (1-30) mm and the mean (range) stone-free rate (SFR) 87.5 (58-100)% with initial therapeutic URS. The majority of these stones were in the ureter (n = 1427, 83.4%). There were 180 (10.5%) Clavien I-III complications and 38 cases (2.2%) where there was a failure to complete the initial ureteroscopic procedure and an alternative procedure was performed. To assess the impact of age on failure rate and complications, studies were subcategorized into those that included children with either a mean age <6 years (four studies, 341 procedures) or a mean age >6 years. (10 studies, 1377 procedures). A higher failure rate (4.4 vs 1.7%) and a higher complication rate (24.0 vs 7.1%) were observed in children whose mean age was <6 years. URS for paediatric stone disease is a relatively safe procedure with a reasonably good SFR, but there seems to be a higher failure and complication rate in children aged <6 years.


Assuntos
Cálculos Ureterais/diagnóstico , Cálculos Ureterais/terapia , Ureteroscopia/métodos , Adolescente , Fatores Etários , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pediatria/métodos
6.
J Laryngol Otol ; 138(1): 83-88, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37194495

RESUMO

BACKGROUND: The British Thyroid Association and American Thyroid Association guideline definitions for low-risk differentiated thyroid cancers are susceptible to differing interpretations, resulting in different clinical management in the UK. OBJECTIVE: To explore the national effect of these guidelines on the management of low-risk differentiated thyroid cancers. METHODS: Anonymised questionnaires were sent to multidisciplinary teams performing thyroidectomies in the UK. Risk factors that multidisciplinary teams considered important when managing low-risk differentiated thyroid cancers were established. RESULTS: Most surgeons (71 out of 75; 94.7 per cent) confirmed they were core multidisciplinary team members. More than 80 per cent of respondents performed at least 30 hemi- and/or total thyroidectomies per annum. A majority of multidisciplinary teams (50 out of 75; 66.7 per cent) followed British Thyroid Association guidelines. Risk factors considered important when managing low-risk differentiated thyroid cancers included: type of tumour histology findings (87.8 per cent), tumour size of greater than 4 cm (86.5 per cent), tumour stage T3b (85.1 per cent) and central neck node involvement (85.1 per cent). Extent of thyroid surgery (e.g. hemi- or total thyroidectomy) was highly variable for low-risk differentiated thyroid cancers. CONCLUSION: Management of low-risk differentiated thyroid cancers is highly variable, leading to a heterogeneous patient experience.


Assuntos
Adenocarcinoma , Neoplasias da Glândula Tireoide , Humanos , Neoplasias da Glândula Tireoide/epidemiologia , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia/métodos , Reino Unido/epidemiologia
7.
J Urol ; 183(5): 1843-7, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20303096

RESUMO

PURPOSE: Diagnosing urinary infection in patients with chronic lower urinary tract symptoms without dysuria is a critical step. In this study we scrutinize the sensitivity and specificity of dipstick urinalysis and microscopic pyuria (10 or more white blood cells per microl) to identify infection in such patients. MATERIALS AND METHODS: This was a prospective, blinded, observational cohort study of urological outpatients with painless lower urinary tract symptoms. Midstream and catheter urine samples were analyzed. A total of 508 midstream urine samples were used to compare leukocyte esterase, nitrite dipstick and urine microscopy with cultures seeking 10(5) cfu/ml. Similarly 470 catheter urine samples were used to compare the same surrogates with 10(5) cfu/ml and with an enhanced culture method seeking 10(2) cfu/ml. A comparison of leukocyte esterase against microscopic pyuria was made using the 508 midstream and 470 catheter specimens of urine. Midstream urine specimens were provided by 42 normal volunteers for comparison. RESULTS: For a midstream urine culture at 10(5) cfu/ml leukocyte esterase was 56% sensitive, nitrite was 10% sensitive and microscopic pyuria was 56% sensitive. Specificities were 66%, 99% and 72%, respectively. For a catheter specimen of urine culture at 10(5) cfu/ml leukocyte esterase was 59% sensitive, nitrite was 20% sensitive and microscopic pyuria was 66% sensitive. Specificities were 84%, 97% and 73%, respectively. The enhanced culture of catheter specimen of urine at 10(2) cfu/ml was positive in 29% of patients vs 15% at 10(5) cfu/ml. CONCLUSIONS: Despite official guidelines and widespread use these tests cannot be considered appropriate for diagnosing urinary tract infection in patients with lower urinary tract symptoms, and should be abandoned in this context.


Assuntos
Biomarcadores/urina , Pacientes Ambulatoriais , Urinálise/métodos , Infecções Urinárias/urina , Adulto , Hidrolases de Éster Carboxílico/urina , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , Disuria , Feminino , Humanos , Masculino , Microscopia , Pessoa de Meia-Idade , Estudos Prospectivos , Piúria/microbiologia , Piúria/urina , Fitas Reagentes , Sensibilidade e Especificidade , Software , Inquéritos e Questionários , Infecções Urinárias/microbiologia
8.
Scand J Urol ; 50(3): 216-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27111193

RESUMO

OBJECTIVE: The aim of this study was to analyse prospective data on flexible ureteroscopy and laser fragmentation (FURSL) of large stones (> 2 cm) to assess whether a ureteral access sheath (UAS) is necessary for the treatment of large renal stones. MATERIALS AND METHODS: Between March 2012 and October 2014, 43 patients with large stones underwent FURSL. Data were collected on a prospective database for patient demographics, stone characteristics and outcomes of FURSL with and without a UAS. RESULTS: There were 27 men and 16 women with a mean age of 54 years (range 7-84 years). The cumulative stone diameter was 2.92 cm (range 2-5 cm), with an overall stone-free rate (SFR) of 83.7%. A total of 68 procedures was needed (average 1.58 procedures/patient). The overall complication rate was 8.8% (n = 6); these were Clavien class II complications associated with urinary tract infections treated with additional antibiotics. UAS was not used in 28 procedures (41.2%). Comparing outcomes in those who had a UAS versus those who did not, there were no statistical differences in SFR, complication rate or average number of procedures per patients. CONCLUSION: Use of a UAS does not make any difference to the SFR or complication rate for FURSL in large stones (> 2 cm) and may not be routinely needed in all cases.


Assuntos
Cálculos Renais/cirurgia , Terapia a Laser , Ureteroscopia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Hospitais Universitários , Humanos , Cálculos Renais/patologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Ureter , Ureteroscópios , Adulto Jovem
9.
J Endourol ; 30(2): 135-45, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26415049

RESUMO

PURPOSE: With a rising incidence of obesity and urolithiasis, we wanted to look at the outcomes of ureteroscopy (URS) for stone management in this group of patients. METHODS: We did a systematic review of literature in accordance with Cochrane review and preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines on all English language articles between 1990 and June 2015 for URS and stone treatment in obese patients. Data were retrieved for patient and stone demographics, outcomes of URS, complications, and follow-up. RESULTS: Fifteen studies (835 patients) were identified with a mean age of 49 years and a mean body mass index (BMI) of 40.5 kg/m(2). The overall stone size was 14.2 mm (range: 3-72 mm) with almost a third of the stones in the lower pole. The initial and final stone-free rate (SFR) was 76.9% and 82.5%, respectively, with an overall complication rate of 9.3% (n = 78). Except one patient with myocardial infarction, all other complications were Clavien grade I-III. The complication rate for morbidly obese patients (17.6%) was twice that of the obese patients (8.4%), although they were all graded as Clavien I or II. CONCLUSION: URS and stone fragmentation are safe and efficient treatment methods in obese patients with a good SFR and a relatively low complication rate, although the complications tend to be higher in the morbidly obese patients.


Assuntos
Cálculos Renais/cirurgia , Obesidade Mórbida/complicações , Cálculos Ureterais/cirurgia , Índice de Massa Corporal , Humanos , Cálculos Renais/complicações , Complicações Pós-Operatórias , Resultado do Tratamento , Cálculos Ureterais/complicações , Ureteroscopia/métodos , Urolitíase/complicações , Urolitíase/cirurgia
10.
J Endourol ; 30(2): 146-52, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26414043

RESUMO

BACKGROUND AND PURPOSE: The advances in both video games and minimally invasive surgery have allowed many to consider the potential positive relationship between the two. This review aims to evaluate outcomes of studies that investigated the correlation between video game skills and performance in laparoscopic surgery. METHODS: A systematic search was conducted on PubMed/Medline and EMBASE databases for the MeSH terms and keywords including "video games and laparoscopy," "computer games and laparoscopy," "Xbox and laparoscopy," "Nintendo Wii and laparoscopy," and "PlayStation and laparoscopy." Cohort, case reports, letters, editorials, bulletins, and reviews were excluded. Studies in English, with task performance as primary outcome, were included. The search period for this review was 1950 to December 2014. RESULTS: There were 57 abstracts identified: 4 of these were found to be duplicates; 32 were found to be nonrelevant to the research question. Overall, 21 full texts were assessed; 15 were excluded according to the Medical Education Research Study Quality Instrument quality assessment criteria. The five studies included in this review were randomized controlled trials. Playing video games was found to reduce error in two studies (P 0.002 and P 0.045). For the same studies, however, several other metrics assessed were not significantly different between the control and intervention group. One study showed a decrease in the time for the group that played video games (P 0.037) for one of two laparoscopic tasks performed. In the same study, however, when the groups were reversed (initial control group became intervention and vice versa), a difference was not demonstrated (P for peg transfer 1 - 0.465, P for cobra robe - 0.185). Finally, two further studies found no statistical difference between the game playing group and the control group's performance. CONCLUSION: There is a very limited amount of evidence to support that the use of video games enhances surgical simulation performance.


Assuntos
Competência Clínica , Simulação por Computador , Laparoscopia/normas , Análise e Desempenho de Tarefas , Jogos de Vídeo , Educação Médica , Humanos , Treinamento por Simulação
11.
Cent European J Urol ; 68(2): 183-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26251738

RESUMO

INTRODUCTION: Renal lower pole stones pose difficulty in management due to anatomical variation, stone size, hardness and patient demographics. Flexible ureterorenoscopy and laser lithotripsy (FURSL) and shock wave lithotripsy (SWL) are preferred for stones 1-2 cm in size. We wanted to compare the outcomes of FURSL and SWL for lower pole stones during the same time period. MATERIAL AND METHODS: All patients who were treated for lower pole stones with FURSL and SWL during a 19-month period were included. The stone free rate (SFR) was defined as ≤3 mm fragments on follow-up imaging or stone free endoscopically. Data was recorded in an excel spreadsheet with SPSS version 21 used for statistical analysis. RESULTS: A total of 161 lower pole procedures were done (93 SWL and 63 FURSL). The mean stone size for SWL (7.4 mm; range: 4-16 mm) was significantly smaller than for FURSL (13.4 mm; 4-53 mm). The mean operating time and hospital stay for FURSL was 65 minutes (range: 30-160 minutes) and 0.5 days (range: 0-7 days) respectively. The SFR was significantly better (p <0.001) for FURSL (n = 63, 93%) compared to SWL (n = 23, 25%). There were 4 (6%) complications (3 Clavien II and 1 Clavien I) in the FURSL group (2 urosepsis, 1 UTI and 1 stent pain). Three patients in the SWL group (Clavien I) were readmitted with renal colic but there were no other complications. CONCLUSIONS: FURSL for lower pole stones seems to be a much better alternative than SWL with a high SFR even for larger stones and seems to be the new gold standard for lower pole stone management.

12.
Urol Ann ; 7(4): 470-4, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26692667

RESUMO

INTRODUCTION AND OBJECTIVES: The management of urolithiasis in patients with horseshoe kidney (HSK) is difficult. Stone formation occurred in 1:5 patients with HSK due to impaired urinary drainage and infections. Percutaneous nephrolithotomy and shock wave lithotripsy can be technically challenging due to altered anatomy. MATERIALS AND METHODS: We conducted a systematic review of the literature to look at the role of ureteroscopy for stone management in these patients. We searched MEDLINE, PubMed and the Cochrane Library from January 1990 to April 2013 for results of ureteroscopy and stone treatment in HSK patients. Inclusion criteria were all English language articles reporting on ureteroscopy in patients with HSK. Data were extracted on the outcomes and complications. RESULTS: A total of 3 studies was identified during this period. Forty-one patients with HSK underwent flexible ureteroscopy and stone treatment. The mean age was 42 with a male:female ratio nearly 3:1. The mean stone size was 16 mm (range: 3-35 mm). The mean operating time was 86 min with multiple stones seen in 15 patients. All 41 patients had a ureteral access sheath used and flexible ureteroscopy and holmium laser fragmentation done. Thirty-two (78%) patients were stone-free with a mean hospital stay of 1-day. Minor complications (Clavien I or II) were seen in 13 (32%) of which 6 had stent discomfort, 3 needed intravenous antibiotics for <24 h, 3 had hematuria of which 2 needed blood transfusion and one had pyelonephritis needing re-admission and antibiotics. There were no major complications found in the review. CONCLUSIONS: Retrograde stone treatment using ureteroscopy and lasertripsy in HSK patients can be performed with good stone clearance rate, but with a slightly higher complication rate. This procedure should, therefore, be done in high volume stone center with an experienced stone surgeon/team.

13.
Urolithiasis ; 42(1): 1-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24374899

RESUMO

Ureteroscopic management of urolithiasis in pregnancy has been on the rise. Technological advancements such as the development of the semi-rigid or flexible ureteroscope, improvements in the design of baskets used for retrieval and the availability of laser have enabled atraumatic fragmentation of stones. We did a systematic review of literature from January 1990 to December 2012. Data were analysed separately for the time period from January 1990 to June 2010 (Period 1) and for last 2.5 years from July 2010 to December 2012 (Period 2). Inclusion criteria were all English language articles with at least three patients reported. Data were extracted on the outcomes and complications reported in the literature. A total of 271 procedures (116 in period 1, 155 in period 2) across 21 studies were reported in the last 22 years. General anaesthesia was used in 38% (44/116) in period 1 and in 64% (99/155) in period 2. The average stone size (7.6 mm) and stone-free rate (SFR) (85%) were similar in both time periods. Fluoroscopy was used in 20% (23/116) and 24% (38/155) in period 1 and 2, respectively. There were fewer complications in period 1 (n = 9) than period 2 (n = 25). These complications were divided into obstetric (n = 5) and non-obstetric complications (n = 29). There were no maternal or foetal deaths during the 22 years. Stone treatment using ureteroscopic techniques in pregnancy can achieve a high success rate. Evidence suggests a rise in the risk of complications with increasing number of these procedures in pregnancy.


Assuntos
Complicações na Gravidez/cirurgia , Ureterolitíase/complicações , Ureterolitíase/cirurgia , Ureteroscopia , Adolescente , Adulto , Feminino , Humanos , Recém-Nascido , Gravidez , Resultado da Gravidez , Resultado do Tratamento , Ureteroscopia/efeitos adversos , Ureteroscopia/métodos , Ureteroscopia/tendências , Adulto Jovem
14.
J Endourol ; 28(10): 1215-23, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25000311

RESUMO

UNLABELLED: Robotic radical cystectomy (RRC) has been growing in popularity across the world as a treatment option for bladder cancer. OBJECTIVES: To compare early surgical outcomes for RRC and open radical cystectomy (ORC) with an emphasis on complications and postoperative mortality rates. EVIDENCE ACQUISITION: A literature review was conducted from 2000 to 2013, including studies comparing RRC and ORC. The main outcome measures analyzed were the complications and mortality rates, in addition to patient demographics, pathological parameters, operating time, estimated blood loss (EBL), transfusion rates, and type of urinary diversion. A meta-analysis was conducted. For continuous data, the Mantel-Haenszel chi-square test was used, and for dichotomous data, inverse variance was used and each expressed as risk ratio with 95% CI. RESULTS: In total, 748 patients were included, 461 patients in the robotic group and 287 patients in the open group (seven studies). There were no significant differences in the demographic parameters of the two groups, except for age (age: p=0.03). There was no difference in the number of muscle-invasive diseases: p=0.47. No difference in positive surgical margin rates (p=0.21). PRIMARY OUTCOMES: The overall (p=0.32) and lower grade (Clavien I-II) (p=0.10) complication rates between the two cohorts did not achieve statistical significance. The high-grade (Clavien III-IV) (p=0.007) complication rates in the ORC group were significantly higher. The mortality rate (Clavien V) was higher in the ORC group (2.2%) compared with the RRC group (0.35%) and this did achieve statistical significance on a meta-analysis (p=0.04). SECONDARY OUTCOMES: The EBL and transfusion rates were statistically significantly lower in the RRC cohort (p<0.00001). The operating time was statistically significantly higher in the RRC cohort (p<0.00001). There was no statistically significant difference in the margin positivity between the two cohorts (p=0.08). CONCLUSION: In early experience, RRC appears to be feasible and a safe alternative to the ORC. RRC appears to have lower high-grade complications and mortality rates compared with the open approach. Although these results are promising, the authors would suggest caution while interpreting these results due to concerns with methodological flaws in the included studies in this review.


Assuntos
Carcinoma de Células de Transição/cirurgia , Cistectomia/métodos , Complicações Pós-Operatórias , Procedimentos Cirúrgicos Robóticos/métodos , Neoplasias da Bexiga Urinária/cirurgia , Idoso , Perda Sanguínea Cirúrgica , Transfusão de Sangue/estatística & dados numéricos , Cistectomia/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Segurança , Resultado do Tratamento , Derivação Urinária
15.
Drug Metab Rev ; 38(3): 353-69, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16877257

RESUMO

In the hippocampus, the center for learning and memory, cytochrome P450s (P450scc, P450(17alpha), and P450arom) as well as 17beta-, 3beta-hydroxysteroid dehydrogenases, and 5alpha-reductase participate in the synthesis of brain steroids from endogenous cholesterol. These brain steroids include pregnenolone, dehydroepiandrosterone, testosterone, dihydrotestosterone, and 17beta-estradiol. Both estrogens and androgens are synthesized in the adult male hippocampal neurons. Although the expression levels of steroidogenic enzymes are as low as 1/200 to 1/50,000 of those in testis or ovary, the levels of synthesized steroids are sufficient for the local usage within small neurons (i.e., intracrine system). This intracrine system contrasts with the endocrine system in which high expression levels of steroidogenic enzymes are necessary in endocrine organs in order to supply steroids to many other organs via blood circulation. Endogenous synthesis of sex steroids in the hypothalamus is also discussed. Rapid modulation by estrogens and xenoestrogens is discussed concerning synaptic plasticity such as the long-term potentiation, the long-term depression, or spinogenesis. Synaptic expression of P450(17alpha), P450arom, and estrogen receptors suggests "synaptocrine" mechanisms of brain steroids, which are synthesized at synapses and act as synaptic modulators.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Estrogênios/biossíntese , Hipocampo/metabolismo , Sinapses/fisiologia , Animais , Sistema Enzimático do Citocromo P-450/fisiologia , Hipocampo/fisiologia , Hipocampo/ultraestrutura , Humanos , Microscopia Imunoeletrônica , Modelos Neurológicos
16.
Proc Natl Acad Sci U S A ; 101(3): 865-70, 2004 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-14694190

RESUMO

In adult mammalian brain, occurrence of the synthesis of estradiol from endogenous cholesterol has been doubted because of the inability to detect dehydroepiandrosterone synthase, P45017alpha. In adult male rat hippocampal formation, significant localization was demonstrated for both cytochromes P45017alpha and P450 aromatase, in pyramidal neurons in the CA1-CA3 regions, as well as in the granule cells in the dentate gyrus, by means of immunohistochemical staining of slices. Only a weak immunoreaction of these P450s was observed in astrocytes and oligodendrocytes. ImmunoGold electron microscopy revealed that P45017alpha and P450 aromatase were localized in pre- and postsynaptic compartments as well as in the endoplasmic reticulum in principal neurons. The expression of these cytochromes was further verified by using Western blot analysis and RT-PCR. Stimulation of hippocampal neurons with N-methyl-d-aspartate induced a significant net production of estradiol. Analysis of radioactive metabolites demonstrated the conversion from [(3)H]pregnenolone to [(3)H]estradiol through dehydroepiandrosterone and testosterone. This activity was abolished by the application of specific inhibitors of cytochrome P450s. Interestingly, estradiol was not significantly converted to other steroid metabolites. Taken together with our previous finding of a P450scc-containing neuronal system for pregnenolone synthesis, these results imply that 17beta-estradiol is synthesized by P45017alpha and P450 aromatase localized in hippocampal neurons from endogenous cholesterol. This synthesis may be regulated by a glutamate-mediated synaptic communication that evokes Ca(2+) signals.


Assuntos
Aromatase/metabolismo , Estradiol/biossíntese , Hipocampo/metabolismo , Pregnenolona/biossíntese , Esteroide 17-alfa-Hidroxilase/metabolismo , Animais , Aromatase/genética , Sinalização do Cálcio , Colesterol/metabolismo , Desidroepiandrosterona/metabolismo , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Imuno-Histoquímica , Técnicas In Vitro , Masculino , Microscopia Imunoeletrônica , N-Metilaspartato/farmacologia , Neurônios/enzimologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Esteroide 17-alfa-Hidroxilase/genética , Testosterona/metabolismo
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