Intramedullary antibiotic coated nail in tibial fracture: a systematic review.

Implant-associated infections remain one of the main problems in trauma surgery, particularly for treatment of open tibial fractures. The role of systemic antibiotic prophylaxis is now established and accepted, but recent literature also seems to emphasize the importance of local antibiotic prophylaxis. Antibiotic coated nails play a crucial role, allowing at the same time the prevention of infections and favoring the stabilization of fractures. These devices appear to be a clinically effective and safe solution. The purpose of the study was to investigate the role of antibiotic coated nails in the treatment of tibia fractures. A literature review was performed on MEDLINE through PubMed to identify scientific publications relevant to the use of antibiotic coated nails in tibial fractures. Primary outcomes were infection rate and bone union rate. This review present numerous limits due primarily to the small number and different nature of studies published; the heterogeneity of the devices used.

Predictable risk factors for infections in proximal femur fractures.

Proximal femur fractures are increasing, together with the aging of world population. One of the complications worsening this condition is infection. In this study, we try to identify risk factors that can lead to infection. We identified 122 patients with femoral neck fracture. The occurrence of infectious events were recorded (respiratory, urinary, superficial wound and periprostethic infection). There were 15 infections, mostly urinary and pulmonary, and all were treated using antibiotics. No statistical differences were found between infection and control group regarding waiting time for surgery, mean time of surgery, age, kind of fracture, type of surgery. Fever onset >38° within 72 hours from surgery was statistically correlated with early infections. Future studies must be led to identify risk factors for infection and to create a strategy to prevent this possibly lethal complication.

Induced membrane by silver-coated knee megaprosthesis: keep or toss?

In the orthopaedic field the foreign body reaction is well known for therapeutic purposes in the alleged Masquelet technique consisting of segmental bone loss two-stage reconstruction. The induced membrane creates advantageous local conditions that promote bone graft remodeling and osteointegration. The aim of our study was to describe the first two cases in Literature of induced membrane observed following silver-coated knee megaprosthesis reconstruction. In addition, it was our interest to evaluate their histological features.

Evaluation of PD1 and PD-L1 expression in high-grade sarcomas of the limbs in the adults: possible implications of immunotherapy.

Sarcomas are a heterogeneous group of rare tumours. Improvements in immunotherapy and the important role of PD1 and PD-L1 expression in advancement and prognosis have opened new fields of research for the treatment of these neoplasia. We evaluated the immunohistochemistry of PD1 and PD-L1 expression in 60 adults' patients affected by high-grade sarcomas of the limbs. PD1 expression was 65% while PD-L1 was 68.3%. PD-L1 expression seems to correlate to Ki67 in liposarcomas, fibrosarcoma's and pleomorphic sarcomas, while it does not show any correlation to chondrosarcomas, while in rhabdomyosarcomas there is a correlation but, given the small sample size, it was not possible to perform a statistic analysis. Our study shows positivity among the different subgroups of positive PD1 lymphocytes infiltration and PD-L1 expression in high-grade sarcomas of the limbs.

Mueller-Weiss disease: review of the literature.

Müller-Weiss (MW) disease is a spontaneous osteonecrosis of the tarsal navicular bone in adults. It is a rare cause of chronic medial midfoot pain and deformity characterized by the collapse of the dorso-lateral part of the navicular, progressive navicular fragmentation and talonavicular joint destruction. This study provides a review of the literature about the epidemiology, etio-pathogenesis, clinical, radiological findings and therapeutic alternatives.

Radiotherapy or chemotherapy for clinical stage IIA and IIB seminoma: a systematic review and meta-analysis of patient outcomes.

BACKGROUND: Outcomes of radiotherapy (RT) compared with chemotherapy (CT) remain poorly defined for clinical stage (CS) IIA and IIB seminoma. We aimed to evaluate the current role of the two treatment modalities in this setting of testicular seminoma. PATIENTS AND METHODS: A systematic review and meta-analysis (MA) was carried out to identify all evaluable studies. Search was limited to studies published after 1990 and included the Medline, Embase databases, and abstracts from ASCO (GU), ESMO, AUA, and ASTRO meetings up to April 2014. Sensitivity analyses were applied including the following: CSIIA and CSIIB, paraortic + iliac RT only in both stages, RT dose (≥30 versus <30 Gy), and PEB/EP regimens only. RESULTS: Thirteen studies have been selected for MA on relapse outcome. No randomized trials compared RT and CT. There were 4 prospective and 9 retrospective studies, with a total of 607 patients receiving RT and 283 patients CT. The pooled relapse rate (RR) was similar between the RT [0.11, 95% confidence interval (CI) 0.08-0.14, P for heterogeneity = 0.096, I(2) = 38%] and CT groups (0.08, 95% CI 0.01-0.15, P for heterogeneity <0.001, I(2) = 82.5%). However, in the sensitivity analysis, the pooled RR for RT in CSIIB was 0.12 (95% CI 0.06-0.17) while it was 0.05 (95% CI 0-0.11) for CT. Long-term side-effects and incidence of second cancers were more frequently reported following RT. The overall incidence of nontesticular second malignancies was 0.04 (95% CI 0.01-0.02) in the RT group and 0.02 (95% CI 0.003-0.04) in the CT group. CONCLUSIONS: Although RT and CT appeared to be equal options in CSIIA and IIB seminoma, a trend in favor of CT for a lower incidence of side-effects and RR in CSIIB was found. This evidence is limited by the retrospective quality of studies and their small sample size.

Aberrant right subclavian artery in fetuses with Down syndrome: a systematic review and meta-analysis.

OBJECTIVES: The primary objective was to estimate the prevalence of aberrant right subclavian artery (ARSA) in fetuses with Down syndrome. Secondary objectives were to assess the prevalence of ARSA in euploid fetuses, the feasibility of ultrasound evaluation of the right subclavian artery (RSA) in the first and second trimesters of pregnancy, the performance of ARSA in screening for trisomy 21 and its association with other abnormalities. METHODS: Web-based databases (PubMed, EMBASE and MEDLINE) were searched up to July 2014. The STROBE, PRISMA and QUIPS instruments were used to assess all included studies and for reporting of methodology, results and conclusions. Original studies that reported prenatal ultrasound evaluation of ARSA, assessment of its prevalence in Down-syndrome and euploid fetuses, feasibility of ultrasound evaluation of the RSA in the first and second trimesters of pregnancy and correlation of ARSA with other abnormalities were included, excluding duplications and case reports. Collected data were summarized to estimate prevalence and feasibility. A meta-analysis was performed pooling the study-specific positive and negative likelihood ratios (LR+ and LR-), detection rates and false-positive rates for trisomy 21. RESULTS: Prevalence of ARSA in Down-syndrome fetuses was 23.6% (95% CI, 19.4-27.9%), whereas in euploid fetuses it was 1.02% (95% CI, 0.86-1.10%). Ultrasound evaluation of the RSA course and origin in the first and second trimesters of pregnancy was feasible in 85% and 98% of cases (first and second trimester, respectively) and it was directly related to sonographic experience and fetal crown-rump length and inversely related to maternal body mass index. In more than 20% of fetuses with ARSA there was an association with other abnormalities but ARSA seemed to be an independent marker of trisomy 21. The meta-analysis showed that ARSA is a significant risk factor for Down syndrome (pooled LR+ = 26.93, 95% CI, 19.36-37.47, P for effect < 0.001, P for Q = 0.3, I(2) = 17.3%), whereas normal RSA is a significant protective marker (pooled LR- = 0.71, 95% CI, 0.51-0.99, P for effect = 0.043, P for Q = 0.9, I(2) = 0%). CONCLUSIONS: ARSA appears to be a clinically useful prenatal ultrasound marker of Down syndrome. Additional testing when ARSA is diagnosed should involve evaluation of all risk factors by applying a mathematical model. There is insufficient evidence to recommend fetal karyotyping in cases with isolated ARSA. If the background risk is higher or additional markers are present, full fetal karyotyping is advisable, including analysis for 22q11 microdeletion.

The Effect of inotropes and vasopressors on mortality: a meta-analysis of randomized clinical trials.

BACKGROUND: Inotropes and vasopressors are frequently administered to critically ill patients in order to improve haemodynamic function and restore adequate organ perfusion. However, some studies have suggested a possible association between inotrope administration and increased mortality. We therefore performed a meta-analysis of randomized trials published in the last 20 yr to investigate the effect of these drugs on mortality. METHODS: BioMedCentral, PubMed, Embase and the Cochrane Central Register were searched (all updated April 8th, 2015). Inclusion criteria were: random allocation to treatment, at least one group receiving an inotropic or vasopressor drug compared with at least one group receiving a non-inotropic/vasopressor treatment, study published after 1st January 1994, and systemic drug administration. Exclusion criteria were overlapping populations, studies published as abstract only, crossover studies, paediatric studies and lack of data on mortality. RESULTS: A total of 28 280 patients from 177 trials were included. Overall, pooled estimates showed no difference in mortality between the group receiving inotropes/vasopressors and the control group [4255/14 036 (31.7%) vs. 4277/14 244 (31.8%), risk ratio=0.98 (0.96-1.01), P for effect=0.23, P for heterogeneity=0.30, I2=6%]. A reduction in mortality was associated with inotrope/vasopressor therapy use in settings of vasoplegic syndromes, sepsis and cardiac surgery. Levosimendan was the only drug associated with improvement in survival. Subgroup analysis did not identify any groups with increased mortality associated with inotrope/vasopressor therapy. CONCLUSIONS: Our systematic review found that inotrope/vasopressor therapy is not associated with differences in mortality in the overall population and in the majority of subsettings.

A Bayesian network meta-analysis on the effect of inodilatory agents on mortality.

BACKGROUND: Inodilators are commonly used in critically ill patients, but their effect on survival has not been properly studied to date. The objective of this work was to conduct a network meta-analysis on the effects of inodilators on survival in adult cardiac surgery patients, and to compare and rank drugs that have not been adequately compared in head-to-head trials. METHODS: Relevant studies were independently searched in BioMedCentral, MEDLINE/PubMed, Embase, and the Cochrane Central Register of clinical trials (updated on May 1, 2014). The criteria for inclusion were: random allocation to treatment with at least one group receiving dobutamine, enoximone, levosimendan, or milrinone and at least another group receiving the above inodilators or placebo, performed in cardiac surgical patients. The endpoint was to identify differences in mortality at longest follow-up available. RESULTS: The 46 included trials were published between 1995 and 2014 and randomised 2647 patients. The Bayesian network meta-analysis found that only the use of levosimendan was associated with a decrease in mortality when compared with placebo (posterior mean of OR=0.48, 95% CrI 0.28 to 0.80). The posterior distribution of the probability for each inodilator to be the best and the worst drug showed that levosimendan is the best agent to improve survival after cardiac surgery. The sensitivity analyses performed did not produce different interpretative result. CONCLUSION: Levosimendan seems to be the most efficacious inodilator to improve survival in cardiac surgery.

Propofol and survival: a meta-analysis of randomized clinical trials.

BACKGROUND: One of the most commonly used hypnotics is propofol. Several studies performed in cardiac surgery suggested an increased mortality in patients receiving a propofol-based total intravenous anaesthesia. Furthermore, the possibility of infections and the 'propofol syndrome' have suggested that propofol might be dangerous. Nonetheless, propofol is widely used in different settings because of its characteristics: fast induction, rapid elimination, short duration of action, smooth recovery from anaesthesia, few adverse effects, no teratogenic effects, characteristics that have undoubtedly contributed to its popularity. The effect of propofol on survival is unknown. We decided to carry out a meta-analysis of all randomized controlled studies ever performed on propofol vs. any comparator in any clinical setting. METHODS: Pertinent studies were independently searched in BioMedCentral, PubMed, Embase, Clinicaltrial.gov, and Cochrane Central Register of Clinical Trials by expert investigators. The following inclusion criteria were used: random allocation to treatment, comparison between propofol and any comparator in any clinical setting. RESULTS: One hundred thirty-three studies randomizing 14,516 patients were included. No differences in mortality between patients receiving propofol [349/6957 (5.0%)] vs. any comparator [340/7559 (4.5%)] were observed in the overall population [risk ratio = 1.05, 95% confidence interval (0.93 to 1.18), P = 0.5] and in several sub-analyses. CONCLUSION: Inspite of theoretical concerns, propofol has no detrimental effect on survival according to the largest meta-analysis of randomized trials ever performed on hypnotic drug.

Single dilator vs. guide wire dilating forceps tracheostomy: a meta-analysis of randomised trials.

BACKGROUND: Single dilator technique (SDT) and guide wire dilating forceps (GWDF) are the two most commonly used techniques of percutaneous dilatational tracheostomy (PDT) in critically ill adult patients. We performed a meta-analysis of randomised, controlled trials comparing intraoperative, mid-term and late complications of these two techniques. METHODS: Pertinent studies were searched in BioMedCentral, PubMed, Embase and the Cochrane Central Register of clinical trials. We selected all randomised studies comparing SDT and GWDF techniques in adult critically ill patients published in a peer-reviewed journal. RESULTS: Among 1040 retrieved studies, five eligible studies randomising 363 patients (181 to GWDF, 182 to SDT) were identified. The incidence of the composite outcome difficult cannula insertion/difficult dilation or failure was higher with the GWDF technique (15.5% vs. 4.9 %, P = 0.02). Moreover, intraprocedural bleeding was more common in the GWDF group (19.3% vs. 7.6% in SDT group, P = 0.018). A trend towards an increased incidence of fracture of tracheal rings was noted in the SDT group (6.5% vs. 0.5% in the GWDF group, P = 0.13). No difference in mid-term or long-term complications was observed. CONCLUSION: GWDF technique is associated with a higher incidence of intraprocedural bleeding and of technical difficulties in completing the procedure (difficult cannula insertions/difficult dilations or failures) compared with the SDT technique. No differences were identified in mid-term and long-term complications. Further studies comparing SDT and GWDF in the general population and in subgroups of high-risk patients (like obese or hypoxaemic patients) are warranted.

Clinical results in patients affected by moderate-severe knee osteoarthritis and treated with micro-fragmented adipose tissue: the therapeutic effects on symptomatology.

Osteoarthrosis is a degenerative musculoskeletal disease that presents a major public health problem, due to the increasing average age of the active population, as well as the increasing percentage of obesity or overweight of the general population. New therapeutic approaches have been developed, such as regenerative medicine that uses mesenchymal stromal cells taken from adipose tissue. This study analyzed the clinical potential benefits of using autologous adipose tissue to treat patients with moderate-severe knee osteoarthritis.In 2021, a total of 50 knees, affected by moderate-severe knee osteoarthritis, were treated with an intra-articular injection of micro-fragmented subcutaneous adipose tissue. Patients were submitted to the KOOS questionnaire before the operation and one year after the operation and VAS pain score at time 0, 3, 6, 12 months.Of the 50 patients treated, 2 patients were excluded from the study. Of the remaining 48 patients, improvements have been achieved in all subclasses of KOOS. In particular, VAS score proves that improvements are more considerable starting from the 3rd month after surgery.The results obtained in this study show the safety and potential benefit of the use of autologous micro-fragmented adipose on people who are affected by moderate-severe knee osteoarthritis.

Anaesthetic drugs and survival: a Bayesian network meta-analysis of randomized trials in cardiac surgery.

BACKGROUND: Many studies have compared desflurane, isoflurane, sevoflurane, total i.v. anaesthesia (TIVA), or all in cardiac surgery to assess their effects on patient survival. METHODS: We performed standard pairwise and Bayesian network meta-analyses; the latter allows indirect assessments if any of the anaesthetic agents were not compared in head-to-head trials. Pertinent studies were identified using BioMedCentral, MEDLINE/PubMed, Embase, and the Cochrane Library (last updated in June 2012). RESULTS: We identified 38 randomized trials with survival data published between 1991 and 2012, with most studies (63%) done in coronary artery bypass grafting (CABG) patients with standard cardiopulmonary bypass. Standard meta-analysis showed that the use of a volatile agent was associated with a reduction in mortality when compared with TIVA at the longest follow-up available [25/1994 (1.3%) in the volatile group vs 43/1648 (2.6%) in the TIVA arm, odds ratio (OR)=0.51, 95% confidence interval (CI) 0.33-0.81, P-value for effect=0.004, number needed to treat 74, I(2)=0%] with results confirmed in trials with low risk of bias, in large trials, and when including only CABG studies. Bayesian network meta-analysis showed that sevoflurane (OR=0.31, 95% credible interval 0.14-0.64) and desflurane (OR=0.43, 95% credible interval 0.21-0.82) were individually associated with a reduction in mortality when compared with TIVA. CONCLUSIONS: Anaesthesia with volatile agents appears to reduce mortality after cardiac surgery when compared with TIVA, especially when sevoflurane or desflurane is used. A large, multicentre trial is warranted to confirm that long-term survival is significantly affected by the choice of anaesthetic.

Infections occurring in adult patients receiving mechanical circulatory support: the two-year experience of an Italian National Referral Tertiary Care Center.

OBJECTIVE: Infection during mechanical circulatory support is a frequent adverse complication. We analyzed infections occurring in this population in a national tertiary care center, and assessed the differences existing between the setting of extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs). DESIGN, SETTING, AND PARTICIPANTS: An observational study was made of patients treated with ECMO or VAD in the San Raffaele Scientific Institute (Italy) between 2009 and 2011. INTERVENTIONS: None. RESULTS: Thirty-nine percent of the 46 patients with ECMO and 69% of the 15 patients with VAD developed infection. We observed a mortality rate of 36.1% during mechanical circulatory support and of 55.7% during the global hospitalization period. Although Gram-negative infections were predominant overall, patients with ECMO were more prone to develop Candida infection (29%), and patients with VAD tended to suffer Staphylococcus infection (18%). Patients with infection had longer ECMO support (p=0.03), VAD support (p=0.01), stay in the intensive care unit (p=0.002), and hospital admission (p=0.03) than patients without infection. Infection (regression coefficient=3.99, 95% CI 0.93-7.05, p=0.02), body mass index (regression coefficient=0.46, 95% CI 0.09-0.83, p=0.02), fungal infection (regression coefficient=4.96, 95% CI 1.42-8.44, p=0.009) and obesity (regression coefficient=10.47, 95% CI 1.77-19.17, p=0.02) were predictors of the duration of ECMO support. Stepwise logistic regression analysis showed the SOFA score at the time of implant (OR=12.33, 95% CI 1.15-132.36, p=0.04) and VAD (OR=1.27, 95% CI 1.04-1.56, p=0.02) to be associated with infection. CONCLUSIONS: Infection is a major challenge during ECMO and VAD support. Each mechanical circulatory support configuration is associated with specific pathogens; fungal infections play a major role.

Proteomic characterization of pseudorabies virus extracellular virions.

Pseudorabies virus (PRV), a member of the Alphaherpesvirinae, has a complex multilayered extracellular virion that is structurally conserved among other herpesviruses. PRV virions contain a double-stranded DNA genome within a proteinaceous capsid surrounded by the tegument, a layer of viral and cellular proteins. The envelope layer, which encloses the capsid and tegument, contains viral transmembrane proteins anchored in a phospholipid bilayer. The viral and host proteins contained within virions execute important functions during viral spread and pathogenesis, but a detailed understanding of the composition of PRV virions has been lacking. In this report, we present the first comprehensive proteomic characterization of purified PRV virions by mass spectrometry using two complementary approaches. To exclude proteins present in the extracellular medium that may nonspecifically associate with virions, we also analyzed virions treated with proteinase K and samples prepared from mock-infected cells. Overall, we identified 47 viral proteins associated with PRV virions, 40 of which were previously localized to the capsid, tegument, and envelope layers using traditional biochemical approaches. Additionally, we identified seven viral proteins that were previously undetected in virions, including pUL8, pUL20, pUL32, pUL40 (RR2), pUL42, pUL50 (dUTPase), and Rsp40/ICP22. Furthermore, although we did not enrich for posttranslational modifications, we detected phosphorylation of four virion proteins: pUL26, pUL36, pUL46, and pUL48. Finally, we identified 48 host proteins associated with PRV virions, many of which have known functions in important cellular pathways such as intracellular signaling, mRNA translation and processing, cytoskeletal dynamics, and membrane organization. This analysis extends previous work aimed at determining the composition of herpesvirus virions and provides novel insights critical for understanding the mechanisms underlying PRV entry, assembly, egress, spread, and pathogenesis.

The IlluminOss® System: a solution in elderly patients with upper limbs bone metastases.

OBJECTIVE: The IlluminOss® System (IS) based on photodynamic bone stabilization (PBS) is a recent option in between the minimally invasive surgical techniques available to treat bone metastases when medical or radiation therapy is neither effective nor indicated, and major surgery is not possible. In this study, the results obtained using IS in the treatment of impending fractures or bone metastases of the upper limb have been analyzed in terms of improvement in pain, quality of life and recovery of function. PATIENTS AND METHODS: Between January 2017 and October 2019, 8 patients over 65 years old with impending fractures or pathological fractures or myeloma of the upper limb have been treated in our institute with IS. All patients were assessed about pain, general health and function of the affected limb before surgery and 1, 3, 6 (consistent with survival) months after the procedure. RESULTS: Mean VAS score improved from 8.88 before surgery to 1.00 six months after surgery, mean Karnofsky index improved at 1 and 3 months post-operative follow-up, and Musculoskeletal Tumor Society Score (MSTS) raised from 44.6 before surgery to 74.7 six months after surgery. Moreover, good reduction and stable fixation of the osteolytic lesion were achieved in all patients, and no complications were found. CONCLUSIONS: Numerous studies have been reported in the literature on the use of this system in osteoporotic elderly fractures, whereas only few articles are currently available regarding its use in the treatment of bone metastases or pathological fractures. From our study PBS seems to be an effective solution in the management of bone metastases or myeloma in both pathological fractures and impending upper limb fractures in patients with low life expectancy.

Antiphospholipid antibodies in patients with purported 'chronic Lyme disease'.

BACKGROUND: Antiphospholipid antibody (aPL) positive patients and patients with purported chronic Lyme disease ('CLD') share many clinical features. After identifying significant aPL in sera of several index patients with 'CLD', we performed aPL tests on all patients referred in whom 'CLD' was suspected, diagnosed or treated. METHODS: All patients with suspected, diagnosed or treated 'CLD' and reportedly 'positive' Lyme assays were studied. aPL testing included anticardiolipin antibodies (aCL), anti-beta-2-glycoprotein-1 antibodies (anti-ß2GP1) and lupus anticoagulant (LAC). Patients were classified into four newly described categories of CLD and data was analyzed. RESULTS: One hundred and six patients were evaluated, of whom 82% had neurologic symptoms and 51% rheumatologic symptoms. Eighty-eight of 106 (83%) patients had positive Lyme serologies (enzyme-linked immunosorbent assay [ELISA] 62/106, 58.4%; western blot [WB] 64/106, 60%), while 18/106 (16.9%) were negative or equivocal. aPL was found in all 'CLD' categories. aCL and/or anti-ß2GP1 were positive in 85/106 (80%), with aCL present in 69/106 (65%) and anti-ß2GP1 present in 69/106 (65%). For all assays, IgM isotypes predominated: WB 55/64 (85%), aCL 63/69 (91%), anti-ß2GP1 52/69 (75%), aCL and/or anti-ß2GP1 74/85 (87%). Anti-ß2GP1 assays occurred in higher titer than aCL: 36/69 (52%) versus 63/69 (91%), p<0.001. Seventeen patients had aPL-related events. Only 12/106 (11.3%) had true post-Lyme syndromes (PLS), category IV, or late Lyme disease (LLD). Most patients had been treated for Lyme: 82/106 (79%). CONCLUSION: aPL occurs frequently in patients with 'CLD'. IgM anti-ß2GP1, IgM aCL and IgM WB were frequently found. Documented PLS or LLD was uncommon. The role of aPL in patients with 'CLD' needs further investigation.

Mechanisms underlying vulnerabilities after repeat mild traumatic brain injuries.

Traumatic brain injury (TBI) has drawn national attention for its high incidence and mechanistic complexity. The majority of TBI cases are "mild" in nature including concussions and mild TBI (mTBI). Concussions are a distinct form of mTBI where diagnosis is difficult, quantification of the incidence is challenging and there is greater risk for subsequent injuries. While concussions occur in the general population, it has become a hallmark injury consistently observed among adolescent and young adult athletes and the risks for repeat TBI (rTBI) is significant. Clinical and experimental evidence shows that the magnitude and duration of deficits is dependent on the number and the interval between injuries. Several studies suggest that metabolic vulnerabilities after injury may contribute to the window for cerebral vulnerability from rTBI. In addition to metabolism, this review addresses how age, sex and hormones also play an important role in the response to repeat concussions. Understanding how these factors collectively contribute to concussion and rTBI recovery is critically important in establishing age/sex appropriate return to play guidelines, injury prevention, therapeutic interventions and mitigation of long-term consequences of rTBI.

Estrogen receptors, estradiol, and diethylstilbestrol in early development: the mouse as a model for the study of estrogen receptors and estrogen sensitivity in embryonic development of male and female reproductive tracts.

To date, there is no conclusive evidence that ERs are present in preimplantation embryos. There are reports that estrogen is made by the rabbit blastocyst (61), and estrogens have been used to induce implantation in mice (62), but whether estrogens act through ERs in the embryo or in the maternal uterus is not known. ERs may be present in early embryos, but if so, levels are below the methods of detection used thus far. Perhaps with more sensitive immunodetection methods, it may be possible to detect ERs in embryos if they are present. Using PCR, messenger RNA for ER has been detected as early as the oocyte stage in mouse embryos (Q. Hou and J. Gorski, unpublished results). This was confirmed recently by Wu et al. (83a). Figure 7 shows a model for the pattern of ER expression in the developing mouse fetus based on the various reports discussed in this review. ERs are present in the 10-day mouse fetus, possibly in the developing ambisexual reproductive tract. Analysis of seven individual 10-day-old fetuses taken from the same litter showed similar levels of an immunostained protein the size of the ER in each fetus (57). The pattern of expression of ER between implantation and the development of the reproductive tract may be the same in male and female mice. Estrogen, acting through ERs, may be one factor (of many) that determines which cells are destined to be part of the indifferent reproductive tract. We were not able to isolate fetal mouse reproductive tracts at an indifferent stage (day 10) due to their very small size. One way to study ER in the indifferent reproductive tract would be to examine these tissues in a larger animal, such as the bovine, using similar immunodetection methods. The distribution of ER in the fetal mouse reproductive tract on fetal days 13 (before sexual differentiation) and 15 (initiation of sexual differentiation) is similar in males and females (71, 72). Thus, estrogen does not appear to be responsible for the initiation of sexual differentiation. Early experiments by Jost (41) showed that removal of the gonad from male or female rabbit fetuses resulted in the female phenotype, which lent weight to the hypothesis that ovarian hormones are not critical in the development of the female phenotype, whereas testicular hormones are essential for the development of the male phenotype.(ABSTRACT TRUNCATED AT 400 WORDS)

A novel mouse kidney 3 beta-hydroxysteroid dehydrogenase complementary DNA encodes a 3-ketosteroid reductase instead of a 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase.

The enzyme 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta HSD) is essential for the biosynthesis of all steroid hormones. The enzyme catalyzes the conversion of delta 5-3 beta-hydroxysteroids to delta 4-3-ketosteroids. We report the isolation of a novel mouse 3 beta HSD cDNA, 3 beta HSD IV, and describe the tissue-specific expression of its mRNA, the enzyme characteristics of the 3 beta HSD IV protein, and the structural and functional relationships it has to other 3 beta HSD isoforms previously characterized in the mouse and rat. The predicted amino acid sequence of mouse 3 beta HSD IV is 77% and 73% identical to that of mouse 3 beta HSD I and III, respectively. Comparison of the nucleotide and amino acid sequences of the four isoforms characterized to date show that 3 beta HSD IV is more distantly related to I, II, and III than these three forms are to each other. 3 beta HSD IV mRNA is only expressed in mouse kidney. In situ hybridization of mouse kidney indicates that expression is found only in the cortex and appears to be associated with the proximal tubules. Transiently expressed 3 beta HSD IV protein could not convert the delta 5-3 beta-hydroxysteroids, pregnenolone or dehydroepiandrosterone, to their respective delta 4-3-ketosteroids, progesterone or androstenedione, nor did it have the capacity to convert 5 alpha-androstane-3 beta, 17 beta-diol to dihydrotestosterone, characteristic enzymatic activities of expressed mouse 3 beta HSD I and III. 3 beta HSD IV could only catalyze the conversion of dihydrotestosterone to 5 alpha-androstanediol in the presence of the cofactor NADPH. Thus, 3 beta HSD IV is a 3-ketosteroid reductase rather than a 3 beta-hydroxysteroid dehydrogenase/isomerase despite its homology to the other members of the 3 beta HSD family. Mouse 3 beta HSD IV is functionally and structurally most closely related to rat 3 beta HSD III, an isoform expressed predominantly in male rat liver.