Diagnosis or prognosis? An umbrella review of mid-trimester cervical length and spontaneous preterm birth

BACKGROUND

Cervical length is widely used to assess a woman's risk of spontaneous preterm birth (SPTB).

OBJECTIVES

To summarise and critically appraise the evidence from systematic reviews on the prognostic capacity of transvaginal sonographic cervical length in the second trimester in asymptomatic women with singleton or twin pregnancy.

SEARCH STRATEGY

Searches were performed in Medline, Embase, CINAHL and grey literature from 1 January 1995 to 6 July 2021, including keywords 'cervical length', 'preterm birth', 'obstetric labour, premature', 'review' and others, without language restriction.

SELECTION CRITERIA

We included systematic reviews including women who did not receive treatments to reduce SPTB risk.

DATA COLLECTION AND ANALYSIS

From 2472 articles, 14 systematic reviews were included. Summary statistics were independently extracted by two reviewers, tabulated and analysed descriptively. The ROBIS tool was used to evaluate risk of bias of included systematic reviews.

MAIN RESULTS

Twelve reviews performed meta-analyses: two were reported as systematic reviews of prognostic factor studies, ten used diagnostic test accuracy methodology. Ten systematic reviews were at high or unclear risk of bias. Meta-analyses reported up to 80 combinations of cervical length, gestational age at measurement and definition of preterm birth. Cervical length was consistently associated with SPTB, with a likelihood ratio for a positive test of 1.70-142.

CONCLUSIONS

The ability of cervical length to predict SPTB is a prognostic research question; systematic reviews typically analysed diagnostic test accuracy. Individual participant data meta-analysis using prognostic factor research methods is recommended to better quantify how well transvaginal ultrasonographic cervical length can predict SPTB.

A randomized, double-blinded, placebo-controlled trial of the effects of infusing local analgesia on post-operative pain during laparoscopic inguinal hernia repair

PURPOSE

While it is widely accepted that laparoscopic total extraperitoneal (TEP) inguinal herniorrhaphy has decreased post-operative pain, there are conflicting data as to whether instillation of local anesthetic into the preperitoneal space improves post-operative pain in these patients. We designed a prospective study to evaluate this. Secondary outcomes include time spent in the PACU, need for narcotic pain medication, and total amount of narcotics required postoperatively.

METHODS

Prospective, randomized, double-blind, placebo-controlled study which enrolled 70 patients with unilateral non-recurrent inguinal hernia from 09/2013 to 03/2019 and included immediate and 2-week post-operative follow-up. All patients received unilateral laparoscopic TEP inguinal hernia repair with control patients receiving 10 ml of 0.9% saline instilled into preperitoneal space while treatment group received 10-ml 0.5% bupivacaine without epinephrine.

RESULTS

A total of 70 patients [67 (96%) men and 3 women; mean age (SD), 57 years (13.8)] were enrolled, 35 randomized into each group. Demographics between the two groups were similar. No differences were found in post-operative pain between the control and test groups at 1 h [mean (SD) of 3.15(2.5) vs 3.21(2.9); P = 0.92], 2 h [3.39 (1.55) vs 2.74 (1.85) P = 0.18], or 1 day [4.79 (2.19) vs 4.39 (2.37); P = 0.13] postoperatively. Likewise, no significant differences were observed in usage of narcotic pain medication postoperatively, as 17 control patients (50%) and 16 (46%) study patients required narcotics within 2 h of surgery (P = 0.72).

CONCLUSION

Instilling local anesthetic into the preperitoneal space during laparoscopic TEP inguinal hernia repair did not result in statistically significant difference in post-operative pain (Rade et al. in NESS Annual Meeting, 2021). Trial registry ClinicalTrials.gov Identifier: NCT02055053.

Effect of poultry offal silage with or without betaine supplementation on growth performance, intestinal morphometry, spleen histomorphology of Nile tilapia (Oreochromis niloticus) fingerlings

Fishmeal (FM) is the main protein source in fish feed. However, it is quite expensive due to its limited resources. Therefore, finding a dietary alternative to the FM to sustain fish production is crucial, and the current study was performed to assess the impact of poultry offal silage (POS) with or without betaine supplementation; as an effective and cheaper alternative to FM; on feed efficiency, growth performance, spleen morphology and intestinal morphometry of Nile tilapia (Oreochromis niloticus) fingerlings. Four dietary treatments were formulated: (1) FM based diet, (2) FM-B; FM diet +0.7% betaine, (3) POS diet and (4) POS-B; POS diet +0.7% betaine. Each dietary treatment consisted of three replicates (n = 10/replicate), and the experiment was continued for 16 weeks. By the end of the experiment, spleen and intestine specimens were collected from 15 fish (n = 5/replicate) for histopathological assessment. The results were statistically analysed using GLM procedures of SAS 9.4. Feed efficiency increased in both POS-B and FM-B groups (p = 0.01), while body weight and body weight gain showed only weak tendencies towards an increase (p = 0.10 and 0.12, respectively). The villi length was the highest in POS-B fed group (p < 0.01). In addition, melanomacrophage centres of the spleen increased in both betaine-supplemented groups (p < 0.01). From our findings, we conclude that betaine supplementation with poultry offal silage improved production performance and immune status of Nile tilapia fish.

Sun-dried Azolla leaf meal at 10% dietary inclusion improved growth, meat quality, and increased skeletal muscle Ribosomal protein S6 kinase β1 abundance in growing rabbit

Rapidly growing human populations and the increased need for high nutritive value meat in terms of low fat, high protein, and low sodium content are the driving reasons for the increase in rabbit meat production. However, dietary protein alternatives to sustain rabbit meat production, without competing with humans for strategic crops are needed. Therefore, the current study was conducted to investigate the effect of Azolla leaf meal (ALM) as a dietary protein source on growth performance, meat quality, and abundance and activation of Ribosomal protein S6 kinase β1 (p70S6K1), a downstream target of mammalian target of rapamycin signalling pathway and, thus, a key player in the regulation of protein synthesis and muscle mass. For this purpose, 60 weaned male V-Line rabbits were blocked for the initial BW and randomly allotted into four dietary treatments, with 15 replicate per treatment (n = 15/group) as follows: (1) CON group was fed on basal diet contains 0% of ALM, (2) AZ10 group fed on diet containing 10% ALM, (3) AZ20 group fed on diet containing 20% ALM, and (4) AZ30 group fed on diet containing 30% ALM. Rabbits were raised individually, and the experimental period was 42 days. At the end of the experiment, rabbits were euthanised and blood and skeletal muscle samples were collected. Body weight and BW gain were the highest in AZ10 group (P = 0.01), while feed intake was the highest in AZ30 (P = 0.01), feed conversion ratio was the lowest in AZ10 and highest in AZ30 (P = 0.01). Dressing % was the highest in AZ10 and lowest in AZ30 groups (P = 0.01). Muscle cross-sectional area was low in both AZ20 and AZ30 groups compared to CON (P = 0.01). The lysine concentration of Longissimus lumborum muscle increased (P = 0.03) while isoleucine tended to decrease in AZ10 vs CON (P = 0.09). The phosphorylation ratio of skeletal muscle p70S6K1 increased in AZ10 and AZ20 groups (P = 0.05). Therefore, ALM could be included in a growing rabbit diet, up to 10%, while higher doses negatively alter production performance, meat quality, and feed efficiency of growing rabbits.

Evaluating symptom burden in kidney transplant recipients: validation of the revised Edmonton Symptom Assessment System for kidney transplant recipients - a single-center, cross-sectional study

We assessed the validity of the Edmonton Symptom Assessment System (ESAS-r) in kidney transplant recipients (KTR). A cross-sectional sample of 252 KTR was recruited. Individual ESAS-r symptom scores and symptom domain scores were evaluated. Internal consistency, convergent validity, and construct validity were assessed with Cronbach's α, Spearman's rank correlations, and a priori-defined risk group comparisons. Mean (SD) age was 51 (16), 58% were male, and 58% Caucasian. ESAS-r Physical, Emotional, and Global Symptom Scores demonstrated good internal consistency (α > 0.8 for all). ESAS-r Physical and Global Symptom Scores strongly correlated with PHQ-9 scores (0.72, 95% CI: 0.64-0.78 and 0.74, 95% CI: 0.67-0.80). For a priori-defined risk groups, individual ESAS-r symptom score differed between groups with lower versus higher eGFR [pain: 1 (0-3) vs. 0 (0-2), delta = 0.18; tiredness: 3 (1-5) vs. 1.5 (0-4), delta = 0.21] and lower versus higher hemoglobin [tiredness: 3 (1-6) vs. 2 (0-4), delta = 0.27]. ESAS-r Global and Physical Symptom Scores differed between groups with lower versus higher hemoglobin [13 (6-29) vs. 6.5 (0-18.5), delta = 0.3, and 9 (2-19) vs. 4 (0-13), delta = 0.24] and lower versus higher eGFR [11 (4-20) vs. 6.5 (2-13), delta = 0.21, and 7 (2-16) vs. 3 (0-9), delta = 0.26]. These data support reliability and construct validity of ESAS-r in KTR. Future studies should explore its clinical utility for symptom assessment among KTR.

Abstract ES2-1: The EMT and metastasis controversy: Where things stand in 2018

A pubmed search for epithelial-mesenchymal transition (EMT) and metastasis brings up almost 9000 papers, the vast majority which provide a positive link between this developmental process, which is hijacked by many tumor cells, and tumor progression. As the field has evolved, it has become apparent that there is not a “one size fits all” definition for EMT, and that the process is instead plastic, with epithelial and mesenchymal states being on the far left and right ends of a continuum where cells can exist in various intermediate states. How do these different intermediate states contribute to metastasis, if they do at all? And do these EMT cancer cells work in isolation, or do they form part of a cooperative network of heterogeneous tumor cells, together facilitating the metastatic process? In this talk, I will discuss the controversy around whether and how EMT is involved in the metastatic process, and the significant progress that we and other labs across the country have made in understanding its role in, and contribution to, the metastatic cascade.

Citation Format: Ford H. The EMT and metastasis controversy: Where things stand in 2018 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr ES2-1.

Exploring the use of tablet computer-based electronic data capture system to assess patient reported measures among patients with chronic kidney disease: a pilot study

Background

Collecting patient reported outcome measures (PROMs) via computer-based electronic data capture system may improve feasibility and facilitate implementation in clinical care. We report our initial experience about the acceptability of touch-screen tablet computer-based, self-administered questionnaires among patients with chronic kidney disease (CKD), including stage 5 CKD treated with renal replacement therapies (RRT) (either dialysis or transplant).

Methods

We enrolled a convenience sample of patients with stage 4 and 5 CKD (including patients on dialysis or after kidney transplant) in a single-centre, cross-sectional pilot study. Participants completed validated questionnaires programmed on an electronic data capture system (DADOS, Techna Inc., Toronto) on tablet computers. The primary objective was to evaluate the acceptability and feasibility of using tablet-based electronic data capture in patients with CKD. Descriptive statistics, Fischer’s exact test and multivariable logistic regression models were used for data analysis.

Results

One hundred and twenty one patients (55% male, mean age (± SD) of 58 (±14) years, 49% Caucasian) participated in the study. Ninety-two percent of the respondents indicated that the computer tablet was acceptable and 79% of the participants required no or minimal help for completing the questionnaires. Acceptance of tablets was lower among patients 70 years or older (75% vs. 95%; p = 0.011) and with little previous computer experience (81% vs. 96%; p = 0.05). Furthermore, a greater level of assistance was more frequently required by patients who were older (45% vs. 15%; p = 0.009), had lower level of education (33% vs. 14%; p = 0.027), low health literacy (79% vs. 12%; p = 0.027), and little previous experience with computers (52% vs. 10%; p = 0.027).

Conclusions

Tablet computer-based electronic data capture to administer PROMs was acceptable and feasible for most respondents and could therefore be used to systematically assess PROMs among patients with CKD. Special consideration should focus on elderly patients with little previous computer experience, since they may require more assistance with completion.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0771-7) contains supplementary material, which is available to authorized users.

'Anyone can edit', not everyone does: Wikipedia's infrastructure and the gender gap

Feminist STS has long established that science's provenance as a male domain continues to define what counts as knowledge and expertise. Wikipedia, arguably one of the most powerful sources of information today, was initially lauded as providing the opportunity to rebuild knowledge institutions by providing greater representation of multiple groups. However, less than ten percent of Wikipedia editors are women. At one level, this imbalance in contributions and therefore content is yet another case of the masculine culture of technoscience. This is an important argument and, in this article, we examine the empirical research that highlights these issues. Our main objective, however, is to extend current accounts by demonstrating that Wikipedia's infrastructure introduces new and less visible sources of gender disparity. In sum, our aim here is to present a consolidated analysis of the gendering of Wikipedia.

Disease-specific quality of life in multiple sclerosis: the effect of disease modifying treatment

Disease specific quality of life was measured in the Leeds Multiple Sclerosis (MS) Treatment Programme (n-/210) using the self-report Leeds MS Quality of Life (LMSQoL) scale. The results showed a significant and sustained increase in quality of life associated with ‘disease modifying’ treatment. This contrasts with the Expanded Disability Status Scores (EDSS), which showed no measurable improvement. An increase in the LMSQoL score did not correlate with baseline age, disease duration, disability or number of prior relapses. There was no significant difference in treatment effect between relapsing-remitting and secondary progressive MS patients, or between patients receiving different products. However, patients with a poor quality of life at baseline showed the most benefit from treatment. Those who had their treatment stopped due to progression, side-effects or lack of effect had significantly lower LMSQoL scores on treatment. In this study, the LMSQoL scale was responsive to change and was easy to administer in a clinical setting.

Nitric oxide in human gingival crevicular fluid after orthodontic force application

Nitric oxide (NO) is involved in bone remodelling and has been shown to play a role in regulating the rate of orthodontic tooth movement (OTM) in rat models. In humans, however, the role of NO in OTM remains less clear. In this study, NO concentration in gingival crevicular fluid (GCF) was measured in patients undergoing orthodontic treatment. Thirteen male participants (ages 11-18 years) planned for non-extraction fixed orthodontic therapy were recruited. Samples of GCF were collected from each maxillary central incisor and first and second molar immediately before (T0), 1h after (T1), and 3-4 days after (T2) application of light orthodontic forces. The maxillary second molars were not included in the appliance and served as controls. Measureable NO levels were consistently obtained from all sampled sites. Total NO levels showed significantly higher NO levels (p<0.05) at T1 at the buccal surfaces of the central incisors when compared to the first and second molars. The results indicate a possible role for NO in OTM at the pressure sites of incisors at early time points. Further studies are required to determine whether NO levels in the periodontal ligament tissues of human teeth during OTM are affected by a force gradient and the magnitude of the applied force.

Holding personal information in a disease-specific register: the perspectives of people with multiple sclerosis and professionals on consent and access

OBJECTIVE

To determine the views of people with multiple sclerosis (MS) and professionals in relation to confidentiality, consent and access to data within a proposed MS register in the UK.

DESIGN

Qualitative study using focus groups (10) and interviews (13).

SETTING

England and Northern Ireland.

PARTICIPANTS

68 people with MS, neurologists, MS nurses, health services management professionals, researchers, representatives from pharmaceutical companies and social care professionals.

RESULTS

People with MS expressed open and altruistic views towards the use of their personal information to facilitate service provision and research, placing trust in responsible guardianship and legitimate use of their information. Participant's proposed that people with MS should be able to select their individual level of involvement in a register using levels of consent. It was agreed that access to the register should be governed by a guardianship committee composed of a range of stakeholders. People with MS did not wish their details to be used by marketing agencies and did not consider this a legitimate use of their data. Whilst participants were positive of the role a register could play in promoting research, participants felt that access to data by pharmaceutical industries should be administered by the guardianship committee. People with MS are concerned should their employers be able to access their personal information. Professionals were more cautious than people with MS in their approach to the use of patient personal data within a register.

CONCLUSIONS

Whilst all stakeholders were positive of the benefits of an MS register, development of such a resource must incorporate robust data security and guardianship measures in order to ensure that, whilst opportunities are maximised, risks to the privacy of individuals and legal challenges to professionals are avoided.

The MS Symptom and Impact Diary (MSSID): psychometric evaluation of a new instrument to measure the day to day impact of multiple sclerosis

OBJECTIVES

This study aimed to develop further a diary originally devised to measure the impact of multiple sclerosis (MS) as part of a cost utility study of beta interferon, and to evaluate its reliability, validity, and responsiveness in an outpatient sample of people with MS.

METHODS

The original diary was further developed using qualitative and quantitative methods to ensure that it addressed the views of people with MS. The psychometric properties of the MS Symptom and Impact Diary (MSSID) were evaluated in a sample of 77 people who completed the MSSID daily for 12 weeks. Internal and test-retest reliability, discriminant and convergent validity, and responsiveness were assessed using traditional psychometric methods.

RESULTS

The MSSID formed three, internally consistent scales that measured mobility, fatigue, and the overall impact of MS. The test-retest reliability of the mobility scale was adequate for individual comparisons (ICC>0.90) and the fatigue and overall impact scales were adequate for group comparisons (ICC>0.70). The MSSID was able to distinguish between clinical groups depending on clinical course, indoor ambulation status, and relapse status. It demonstrated associations with other single point instruments in the expected direction. Compared with single point instruments, its responsiveness was similar or better, especially in detecting short term improvements in functioning.

CONCLUSIONS

The MSSID may provide a useful complement to currently available instruments to measure the outcomes of MS within clinical trials. Further research is needed to explore its feasibility in the context of a randomised controlled trial and its utility for clinicians.

Biosynthetic ganciclovir triphosphate: its isolation and characterization from ganciclovir-treated herpes simplex thymidine kinase-transduced murine cells

A method is described for the preparation of ganciclovir triphosphate (GCV-TP) using murine colon cancer cells (MC38) transduced with the herpes simplex virus-thymidine kinase (MC38/HSV-tk). Murine cells transduced with viral-tk contain required viral and host enzymes needed for complete cellular synthesis of this potent antiviral metabolite. Dose response studies showed optimal intracellular levels of GCV-TP occurred after exposure of MC38/HSV-tk cells to 300 microM ganciclovir for 24 h producing 7.5 nmol GCV-TP/10(6) cells. This reflects cellular accumulation of GCV-TP to levels 25-fold greater than the medium concentration of parent drug. A simple isolation scheme included methanolic extraction and anion-exchange chromatography to recover the target triphosphate. Mass spectral analysis and selective enzyme degradation provided structural confirmation of the purified product. Biological activity of the purified GCV-TP was demonstrated by competitive inhibition experiments using human DNA polymerase alpha and HSV DNA polymerase that showed substantially greater sensitivity for the viral polymerase in agreement with previous reports. The GCV-TP obtained was further used to enzymatically prepare GCV mono- and diphosphate in high yield. This method provides an easily scalable means of preparing milligram amounts of the triphosphates of pharmacologically active acyclic nucleosides like ganciclovir.

The clinical and laboratory features of chronic sensory ataxic neuropathy with anti-disialosyl IgM antibodies

The clinical and laboratory phenotype of a paraproteinaemic neuropathy syndrome termed chronic sensory ataxic neuropathy with anti-disialosyl IgM antibodies is described in a series of 18 cases. Previous single case reports have outlined some features of this syndrome. All 18 cases were defined by the presence of serum IgM antibodies which react principally with NeuAc (alpha2-8)NeuAc(alpha2-3)Gal-configured disialosyl epitopes common to many gangliosides including GDlb, GD3, GTlb and GQlb. In 17 out of 18 cases, the serum contained benign IgM paraproteins, and in four of these cases at least two IgM paraproteins were present. The IgM antibodies were also cold agglutinins in 50% of cases. The clinical picture comprised a chronic neuropathy with marked sensory ataxia and areflexia, and with relatively preserved motor function in the limbs. In addition, 16 out of 18 cases had motor weakness affecting oculomotor and bulbar muscles as fixed or as relapsing-remitting features. When present in their entirety, these clinical features have been described previously under the acronym CANOMAD: chronic ataxic neuropathy, ophthalmoplegia, IgM paraprotein, cold agglutinins and disialosyl antibodies. This distribution of clinical features is reminiscent of Miller Fisher syndrome, in which acute-phase anti-disialylated ganglioside IgG antibodies are found. Clinical electrophysiology and nerve biopsy show both demyelinating and axonal features. A partial response to intravenous immunoglobulin and other treatments is reported in some cases.

Acute pancreatitis and bacterial translocation

Infectious complications are the most frequent and severe complications of acute narcotizing pancreatitis (AP) with a mortality rate up to 80%. Although experimental and clinical studies suggest that the microbiologic source of pancreatic infection could be enteric, information in this regard is scant. This study evaluated bacterial translocation (BT) using mild and severe models of AP. Mild AP was induced by 6-hr continuous intravenous infusion of cerulein, while severe AP was induced by additional infusion of glycodeoxycholic acid into the biliopancreatic duct. BT was evaluated with organ cultures performed when animals were killed (24 hr). To confirm the gastrointestinal origin of the translocating microorganisms, fluorescent microspheres were also given to the animals in drinking water 24 hr before induction of AP. At the time of death beads were counted with a (fluorescence-activated cell sorter) (FACS) in peritoneal lavages and with fluorescent microscopy in frozen sections of the pancreata. Morphology of the distal small bowel showed significant changes in the animals with AP compared to controls, such as reduction of villus high and altered microvasculature. Mild AP induced BT to the pancreas in 100% of the animals, compared to pancreata from control groups. Severe AP induced increased BT to the pancreas. BT to liver and spleen was also significantly increased with AP. The presence of fluorescent microspheres confirmed their enteric derivation. This study provides evidence for the enteric origin of microorganisms responsible for pancreatic infectious complications during AP. The evidence of BT after laparotomy suggests an increased risk of infections with the association of these conditions. This could provide an explanation for the high mortality associated with laparotomy in course of AP.

Evaluation of a fluorogenic derivatization method for the reversed-phase HPLC analysis of 2'-beta-fluoro-2',3'-dideoxyadenosine, a new anti-AIDS drug

High sensitivity (10(-7) to 10(-9) M) reversed-phase high-performance liquid chromatography (HPLC) analysis of adenine nucleosides and nucleotides, especially in a biological matrix, is difficult using only ultraviolet detection. Derivatization coupled with fluorescence detection has been investigated as a means of enhancing sensitivity for the reversed-phase HPLC analysis of 2'-beta-fluoro-2',3'-dideoxyadenosine (F-ddA), an experimental, acid-stable, anti-AIDS drug. The reaction of chloroacetaldehyde with the adenine base has been employed to form fluorescent 1,N(6)-etheno derivatives of F-ddA and 5'-deoxyadenosine, which is used as an internal standard. These derivatives give an analytically useful fluorescence emission at 416 nm after excitation at 230, 265, or 275 nm. Derivatization, fluorescence detection and reversed-phase chromatography have been optimized for the analysis of nanomolar concentrations of F-ddA in human plasma. This method has potential for the measurement of F-ddA at low concentration and in limited volume samples from in vivo biological studies.

The effects of core and peripheral warming methods on temperature and physiologic variables in injured children

INTRODUCTION

Injured children are at risk for thermoregulatory compromise, where temperature maintenance mechanisms are overwhelmed by severe injury, environmental exposure, and resuscitation measures. Adequate thermoregulation can be maintained, and heat loss can be prevented, by core (administration of warmed intravenous fluid) and peripheral (application of convective air warming) methods. It is not known which warming method is better to maintain thermoregulation and prevent heat loss in injured children during their trauma resuscitations. The purpose of this feasibility study was to compare the effects of core and peripheral warming measures on body temperature and physiologic changes in a small sample of injured children during their initial emergency department (ED) treatment.

METHODS

A prospective, randomized experimental design was used. Eight injured children aged 3 to 14 years (mean = 6.87, SD = 3.44 ) treated in the ED of Children's Hospital of Pittsburgh were enrolled. Physiologic responses (eg, heart rate, blood pressure, respiratory rate, arterial oxygen saturation, core, peripheral temperatures) and level of consciousness were continuously measured and recorded every 5 minutes to detect early thermoregulatory compromise and to determine the child's response to warming. Data were collected throughout the resuscitation period, including transport to CT scan, the inpatient nursing unit, intensive care unit, operating room or discharge to home. Core warming was accomplished with the Hotline Fluid Warmer (Sims Level 1, Inc., Rockland, MA), and peripheral warming was accomplished with the Snuggle Warm Convective Warming System (Sins Level 1, Inc., Rockland, MA). Data were analyzed using descriptive and inferential statistics.

RESULTS

There were no statistically significant differences between the two groups on age (t = -0.485, P = 0.645); weight (t = -0.005, P = 0.996); amount of prehospital intravenous (IV) fluid (t = 0314, P = 0.766); temperature on ED arrival (t = 0.287, P = 0.784); total amount of infused IV fluid (t = -0.21, P = 0.8); and length of time from ED admission to hospital admission (t = -0.613, P = 0.56). There were no statistically significant differences between the two groups on RTS (t = -0.516, P = 0.633). When comparing the mean differences in temperature upon hospital admission, no statistically significant differences were found (t = -1.572, P = 0.167). There were no statistically significant differences between the two groups in tympanic [F(15) = 0.71, P = 0.44] and skin [F(15) = 0.06, P = 0.81] temperature measurements over time.

CONCLUSION

Core and peripheral warming methods appeared to e effective in preventing heat loss in this stable patient population. A reasonable next step would be to continue this trial in a larger sample of patients who are at greater risk for heat loss and subsequent hypothermia and to use a control group.

Fluorometric determination of 2'-beta-fluoro-2',3'-dideoxyadenosine 5'-triphosphate, the active metabolite of a new anti-human immunodeficiency virus drug, in human lymphocytes

A sensitive precolumn derivatization method has been developed to measure the 5'-triphosphate of 2'-beta-fluoro-2',3'-dideoxyadenosine (F-ddA, lodenosine), a new anti-HIV drug, in human lymphocytes by HPLC using fluorescence detection. Reaction of chloroacetaldehyde with F-ddA triphosphate in extracts from human lymphocytes produces a highly fluorescent etheno adduct. This derivative is then separated and quantitated by reverse-phase paired-ion chromatography. Degradation of natural nucleic acid ribosides, such as ATP, using periodate oxidation simplifies the chromatogram and minimizes interference with detection of the target analyte. This method, modeled using cultured MOLT-4 T-lymphocytes, achieves a linear detector response for peak area measurements over the range 2.5 to 22.5 pmol (50-450 nM using 50 microl sample). Analyte recovery is greater than 90%, and the method achieves a limit of detection and limit of quantitation of 1.4 and 2.5 pmol per HPLC injection (50 microl sample containing cellular extract from 2.5 x 10(6) cells), respectively. Application of this method to measure F-ddATP in peripheral blood mononuclear cells from HIV-infected patients treated with F-ddA at 3.2 mg/kg twice daily for 22 days shows F-ddATP levels which range from 1.5 to 3.5 pmol/10(6) cells.

A remarkably simple chemicoenzymatic approach to structurally complex bicyclo[3.1.0]hexane carbocyclic nucleosides

[reaction: see text] Intramolecular cyclopropanation of a carbene engendered from the corresponding diazo beta-ketoester produced the desired bicyclo[3.1. 0]hexane pseudosugar. Purine nucleosides obtained via Mitsunobu coupling were resolved with adenosine deaminase. The requisite beta-ketoester was assembled in one step from ethyl acetoacetate and acrolein.

Glutamatergic regulation of gonadotropin releasing hormone mRNA levels during development in the mouse

The aims of these studies were to investigate the time course of the increase in gonadotropin releasing hormone (GnRH) mRNA levels during sexual development in the mouse, and to test the hypothesis that the neurotransmitter glutamate regulates the GnRH secretory system via actions at the level of GnRH gene expression. GnRH mRNA abundance was estimated by measuring silver grains generated by in situ hybridization of an 35S-labelled oligonucleotide probe. There was a significant increase in GnRH mRNA abundance between the day of birth (P0) and postnatal day 2 (P2) in male mice, but no further increases at later ages when overt pubertal changes are manifest. GnRH mRNA levels also increased significantly between P0 and P2 in female mice. Treatment with the glutamate agonist NMDA caused a significant increase in GnRH mRNA levels in neonatal (P0) mice and adult male mice within 30 min of treatment, which is consistent with previous studies in the rat implicating glutamate in the regulation of GnRH mRNA stability. Treatment with the glutamate antagonist CGP40116 caused an equally rapid decrease in GnRH mRNA levels in adult mice and in mice on P5 after the neonatal increase in GnRH gene expression, but was without effect in mice on P0, prior to the developmental increase. These observations that the effect on GnRH mRNA levels of blocking endogenous glutamatergic signalling depends upon the developmental stage suggest that endogenous glutamate maintains GnRH mRNA levels in adult mouse, and is a potential regulator of the developmental increase seen in the neonatal period.

Interactions of conformationally biased north and south 2'-fluoro-2', 3'-dideoxynucleoside 5'-triphosphates with the active site of HIV-1 reverse transcriptase

Molecular dynamics simulations of a ternary complex of HIV-1 reverse transcriptase (RT), double-stranded DNA, and bound dideoxynucleoside-5'-triphosphate (RT-DNA-ddNTP), utilizing the ddNTPs ddATP, betaFddATP, and alphaFddATP, explain the experimentally observed order of potency of these 5'-triphosphates as inhibitors of RT: ddATP > betaFddATP > alphaFddATP. On the basis of RT's known preference to bind the incoming dNTP (or ddNTP) with a north conformation at the polymerase site, alphaFddATP, which in solution prefers almost exclusively a north conformation, was predicted to be the most potent inhibitor. However, Tyr115, which appears to function as a steric gate to preclude the binding of ribonucleoside 5'-triphosphates, prevents the effective binding of alphaFddATP in its preferred north conformation. The south-biased betaFddATP, while able to bind to RT without hindrance by Tyr115, has to pay a high energy penalty to be flipped to the active north conformation at the polymerase site. Finally, the more flexible and less conformationally biased ddATP is able to switch to a north conformation at the RT site with a smaller energy penalty than betaFddATP. These results highlight the opposite conformational preferences of HIV-1 RT for alphaFddATP and betaFddATP and help establish conformational guidelines for optimal binding at the polymerase site of this enzyme.

Estrogenic induction of spermatogenesis in the hypogonadal mouse

Abnormal sperm production and reduced fertility have been reported in transgenic male mice lacking the alpha-subtype of the estrogen receptor (ER)alpha or aromatase. The aim of this study was to investigate the role of estrogen in male reproductive function, by determining the effect of estradiol on testicular function in hypogonadal (hpg) mice congenitally lacking gonadotropin; and thus, sex steroid production. hpg mice were treated, at 2-3 months of age, with slow-release estradiol implants, which achieved circulating estradiol concentrations of approximately 40 pg/ml. Treatment for 35 days reliably induced a 4- to 6-fold increase in testicular weight, compared with the vestigial testes in the untreated or cholesterol-treated controls. The degree of testicular growth after 35 days was similar to that in hpg mice receiving an intrahypothalamic graft of preoptic area tissue taken from neonatal mice on the day of birth, a procedure known to induce testicular development in hpg mice by activation of the pituitary gland. Histological analysis revealed that the testes contained elongated spermatids after 35 days of estradiol treatment, whereas germ cell development never progressed beyond the pachytene stage in control hpg mice. Treatment for 70 days induced full qualitatively normal spermatogenesis in hpg mice. Testis weight increased 5-fold, reflecting a 5-fold increase in total seminiferous tubule volume and a 4- to 5-fold increase in the total volume of the seminiferous epithelium. In all experiments, spermatogenesis proceeded in the absence of measurable androgen concentrations, but circulating FSH concentrations were slightly (but significantly) elevated, relative to cholesterol-treated control hpg mice. This stimulatory action of estradiol on FSH secretion was unexpected, particularly because identical estradiol treatments significantly decreased serum FSH levels in wild-type littermates. These results indicate that estrogens may play a role in spermatogenesis, via stimulatory effects on FSH secretion. An alternative or complementary explanation, given the recent identification of estrogen receptors (ERalpha and ERbeta) and aromatase within various cell types in the testis, is that estrogens exert paracrine actions within the testis to promote spermatogenesis. The identification of effects of estradiol on testicular function provides a conceptual basis to reexamine the speculative link between increased exposure to environmental estrogens and reduced fertility in man.

Adenosine deaminase prefers a distinct sugar ring conformation for binding and catalysis: kinetic and structural studies

Several recent X-ray crystal structures of adenosine deaminase (ADA) in complex with various adenosine surrogates have illustrated the preferred mode of substrate binding for this enzyme. To define more specific structural details of substrate preferences for binding and catalysis, we have studied the ADA binding efficiencies and deamination kinetics of several synthetic adenosine analogues in which the furanosyl ring is biased toward a particular conformation. NMR solution studies and pseudorotational analyses were used to ascertain the preferred furanose ring puckers (P, nu(MAX)) and rotamer distributions (chi and gamma) of the nucleoside analogues. It was shown that derivatives which are biased toward a "Northern" (3'-endo, N) sugar ring pucker were deaminated up to 65-fold faster and bound more tightly to the enzyme than those that preferred a "Southern" (2'-endo, S) conformation. This behavior, however, could be modulated by other structural factors. Similarly, purine riboside inhibitors of ADA that prefer the N hemisphere were more potent inhibitors than S analogues. These binding propensities were corroborated by detailed molecular modeling studies. Docking of both N- and S-type analogues into the ADA crystal structure coordinates showed that N-type substrates formed a stable complex with ADA, whereas for S-type substrates, it was necessary for the sugar pucker to adjust to a 3'-endo (N-type) conformation to remain in the ADA substrate binding site. These data outline the intricate structural details for optimum binding in the catalytic cleft of ADA.

NOX, a novel nitric oxide scavenger, reduces bacterial translocation in rats after endotoxin challenge

Endotoxemia promotes gut barrier failure and bacterial translocation (BT) by upregulating inducible nitric oxide synthase (iNOS) in the gut. We hypothesized that administration of a dithiocarbamate derivative, NOX, which scavenges nitric oxide (NO), may reduce intestinal injury and BT after lipopolysaccharide (LPS) challenge. Sprague-Dawley rats were randomized to receive NOX or normal saline via subcutaneously placed osmotic pumps before or after LPS challenge. Mesenteric lymph nodes, liver, spleen, and blood were cultured 24 h later. Transmucosal passage of Escherichia coli C-25 or fluorescent beads were measured in an Ussing chamber. Intestinal membranes were examined morphologically for apoptosis, iNOS expression, and nitrotyrosine immunoreactivity. NOX significantly reduced the incidence of bacteremia, BT, and transmucosal passage of bacteria and beads when administered before or up to 12 h after LPS challenge. LPS induced enterocyte apoptosis at the villus tips where bacterial entry was demonstrated by confocal microscopy. NOX significantly decreased the number of apoptotic nuclei and nitrotyrosine residues. NOX prevents LPS-induced gut barrier failure by scavenging NO and its toxic derivative, peroxynitrite.

Seasonal regulation of food intake and body weight in the male Siberian hamster: studies of hypothalamic orexin (hypocretin), neuropeptide Y (NPY) and pro-opiomelanocortin (POMC)

The aim of these experiments was to investigate the relationship between hypothalamic expression of orexin (also called hypocretin), neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) mRNA and seasonal cycles of body weight and food intake in the Siberian hamster. Adult males were transferred from long days of 16 h light and 8 h dark to short days of 8 h light and 16 h dark, a procedure known to induce major reductions in food intake and body weight in this species. After 8 weeks of exposure to short days, while body weight was declining, hypothalamic NPY mRNA levels as assessed by in situ hybridization were slightly lower (P < 0.05) than in age-matched controls exposed to long days. After 12 weeks with short days, when body weight would be expected to have reached its seasonal nadir, POMC mRNA levels were lower (P < 0.05) than in hamsters under long days. At no stage did orexin mRNA levels in hamsters under short days differ significantly from levels in those under long days. To investigate further the role of these peptide systems in seasonal changes in body weight and food intake, two provocative tests were carried out. Firstly, a 48-h fast induced a significant increase (P < 0.025) in hypothalamic NPY mRNA levels in both long- and short-day conditions, but did not change hypothalamic POMC or orexin mRNA levels. Secondly, systemic (intraperitoneal) treatment with recombinant murine leptin (5 mg/kg body weight) significantly decreased (P < 0.01) food intake over a 6-h post-treatment period in both long- and short-day conditions. However, this acute leptin treatment did not induce significant changes in hypothalamic orexin, NPY or POMC mRNA abundance. The increase in NPY expression in both long- and short-day conditions following food restriction and the suppression of food intake by leptin in both conditions suggests that acute homeostatic mechanisms operate in both long-day (obese) and short-day (nonobese) conditions. The lack of major changes in orexin, NPY and POMC in such different metabolic states suggest that other central systems must play a greater role in generating these states. Such findings are consistent with the 'sliding set-point' hypothesis, that is, seasonal cycles in food intake and fat metabolism are brought about by as yet unknown central mechanisms that chronically alter the level ('set point') around which homeostasis occurs, rather than resulting from changes in the potency of the acute feedback mechanisms themselves.

Conformationally restricted nucleosides. The reaction of adenosine deaminase with substrates built on a bicyclo[3.1.0]hexane template

Adenosine deaminase (ADA) can discriminate between two distinct (North and South), conformationally rigid substrate conformers. (N)-methanocarba-2'dA (4) is deaminated 100 times faster than the antipodal (S)-methanocarba-2'dA (5), whereas a non-rigid analogue, aristeromycin (6), is deaminated at an intermediate rate. These results are in agreement with crystallographic data from ADA-ribonucleoside complexes showing the furanose ring of the bound purine in a C3'-endo (North) conformation. The data presented here suggests that 4 and 5 are useful probes to ascertain conformational preferences by purine metabolizing enzymes.

Mechanism of inhibition of DNA (cytosine C5)-methyltransferases by oligodeoxyribonucleotides containing 5,6-dihydro-5-azacytosine

A key step in the predicted mechanism of enzymatic transfer of methyl groups from S-adenosyl-l-methionine (AdoMet) to cytosine residues in DNA is the transient formation of a dihydrocytosine intermediate covalently linked to cysteine in the active site of a DNA (cytosine C5)-methyltransferase (DNA C5-MTase). Crystallographic analysis of complexes formed by HhaI methyltransferase (M.HhaI), AdoMet and a target oligodeoxyribonucleotide containing 5-fluorocytosine confirmed the existence of this dihydrocytosine intermediate. Based on the premise that 5,6-dihydro-5-azacytosine (DZCyt), a cytosine analog with an sp3-hybridized carbon (CH2) at position 6 and an NH group at position 5, could mimic the non-aromatic character of the cytosine ring in this transition state, we synthesized a series of synthetic substrates for DNA C5-MTase containing DZCyt. Substitution of DZCyt for target cytosines in C-G dinucleotides of single-stranded or double-stranded oligodeoxyribonucleotide substrates led to complete inhibition of methylation by murine DNA C5-MTase. Substitution of DZCyt for the target cytosine in G-C-G-C sites in double-stranded oligodeoxyribonucleotides had a similar effect on methylation by M. HhaI. Oligodeoxyribonucleotides containing DZCyt formed a tight but reversible complex with M.HhaI, and were consistently more potent as inhibitors of DNA methylation than oligodeoxyribonucleotides identical in sequence containing 5-fluorocytosine. Crystallographic analysis of a ternary complex involving M.HhaI, S-adenosyl-l-homocysteine and a double-stranded 13-mer oligodeoxyribonucleotide containing DZCyt at the target position showed that the analog is flipped out of the DNA helix in the same manner as cytosine, 5-methylcytosine, and 5-fluorocytosine. However, no formation of a covalent bond was detected between the sulfur atom of the catalytic site nucleophile, cysteine 81, and the pyrimidine C6 carbon. These results indicate that DZCyt can occupy the active site of M.HhaI as a transition state mimic and, because of the high degree of affinity of its interaction with the enzyme, it can act as a potent inhibitor of methylation.