A quantitative evaluation of aerosol generation during cardiopulmonary resuscitation

It is unclear if cardiopulmonary resuscitation is an aerosol-generating procedure and whether this poses a risk of airborne disease transmission to healthcare workers and bystanders. Use of airborne transmission precautions during cardiopulmonary resuscitation may confer rescuer protection but risks patient harm due to delays in commencing treatment. To quantify the risk of respiratory aerosol generation during cardiopulmonary resuscitation in humans, we conducted an aerosol monitoring study during out-of-hospital cardiac arrests. Exhaled aerosol was recorded using an optical particle sizer spectrometer connected to the breathing system. Aerosol produced during resuscitation was compared with that produced by control participants under general anaesthesia ventilated with an equivalent respiratory pattern to cardiopulmonary resuscitation. A porcine cardiac arrest model was used to determine the independent contributions of ventilatory breaths, chest compressions and external cardiac defibrillation to aerosol generation. Time-series analysis of participants with cardiac arrest (n = 18) demonstrated a repeating waveform of respiratory aerosol that mapped to specific components of resuscitation. Very high peak aerosol concentrations were generated during ventilation of participants with cardiac arrest with median (IQR [range]) 17,926 (5546-59,209 [1523-242,648]) particles.l-1 , which were 24-fold greater than in control participants under general anaesthesia (744 (309-2106 [23-9099]) particles.l-1 , p < 0.001, n = 16). A substantial rise in aerosol also occurred with cardiac defibrillation and chest compressions. In a complimentary porcine model of cardiac arrest, aerosol recordings showed a strikingly similar profile to the human data. Time-averaged aerosol concentrations during ventilation were approximately 270-fold higher than before cardiac arrest (19,410 (2307-41,017 [104-136,025]) vs. 72 (41-136 [23-268]) particles.l-1 , p = 0.008). The porcine model also confirmed that both defibrillation and chest compressions generate high concentrations of aerosol independent of, but synergistic with, ventilation. In conclusion, multiple components of cardiopulmonary resuscitation generate high concentrations of respiratory aerosol. We recommend that airborne transmission precautions are warranted in the setting of high-risk pathogens, until the airway is secured with an airway device and breathing system with a filter.

Quantitative evaluation of aerosol generation during manual facemask ventilation

Manual facemask ventilation, a core component of elective and emergency airway management, is classified as an aerosol-generating procedure. This designation is based on one epidemiological study suggesting an association between facemask ventilation and transmission during the SARS-CoV-1 outbreak in 2003. There is no direct evidence to indicate whether facemask ventilation is a high-risk procedure for aerosol generation. We conducted aerosol monitoring during routine facemask ventilation and facemask ventilation with an intentionally generated leak in anaesthetised patients. Recordings were made in ultraclean operating theatres and compared against the aerosol generated by tidal breathing and cough manoeuvres. Respiratory aerosol from tidal breathing in 11 patients was reliably detected above the very low background particle concentrations with median [IQR (range)] particle counts of 191 (77-486 [4-1313]) and 2 (1-5 [0-13]) particles.l-1 , respectively, p = 0.002. The median (IQR [range]) aerosol concentration detected during facemask ventilation without a leak (3 (0-9 [0-43]) particles.l-1 ) and with an intentional leak (11 (7-26 [1-62]) particles.l-1 ) was 64-fold (p = 0.001) and 17-fold (p = 0.002) lower than that of tidal breathing, respectively. Median (IQR [range]) peak particle concentration during facemask ventilation both without a leak (60 (0-60 [0-120]) particles.l-1 ) and with a leak (120 (60-180 [60-480]) particles.l-1 ) were 20-fold (p = 0.002) and 10-fold (0.001) lower than a cough (1260 (800-3242 [100-3682]) particles.l-1 ), respectively. This study demonstrates that facemask ventilation, even when performed with an intentional leak, does not generate high levels of bioaerosol. On the basis of this evidence, we argue facemask ventilation should not be considered an aerosol-generating procedure.

A quantitative evaluation of aerosol generation during supraglottic airway insertion and removal

Many guidelines consider supraglottic airway use to be an aerosol-generating procedure. This status requires increased levels of personal protective equipment, fallow time between cases and results in reduced operating theatre efficiency. Aerosol generation has never been quantitated during supraglottic airway use. To address this evidence gap, we conducted real-time aerosol monitoring (0.3-10-µm diameter) in ultraclean operating theatres during supraglottic airway insertion and removal. This showed very low background particle concentrations (median (IQR [range]) 1.6 (0-3.1 [0-4.0]) particles.l-1 ) against which the patient's tidal breathing produced a higher concentration of aerosol (4.0 (1.3-11.0 [0-44]) particles.l-1 , p = 0.048). The average aerosol concentration detected during supraglottic airway insertion (1.3 (1.0-4.2 [0-6.2]) particles.l-1 , n = 11), and removal (2.1 (0-17.5 [0-26.2]) particles.l-1 , n = 12) was no different to tidal breathing (p = 0.31 and p = 0.84, respectively). Comparison of supraglottic airway insertion and removal with a volitional cough (104 (66-169 [33-326]), n = 27), demonstrated that supraglottic airway insertion/removal sequences produced <4% of the aerosol compared with a single cough (p < 0.001). A transient aerosol increase was recorded during one complicated supraglottic airway insertion (which initially failed to provide a patent airway). Detailed analysis of this event showed an atypical particle size distribution and we subsequently identified multiple sources of non-respiratory aerosols that may be produced during airway management and can be considered as artefacts. These findings demonstrate supraglottic airway insertion/removal generates no more bio-aerosol than breathing and far less than a cough. This should inform the design of infection prevention strategies for anaesthetists and operating theatre staff caring for patients managed with supraglottic airways.

The public health potential of two popular apps to increase physical activity

Background

The rise of health apps created novel prospects for public health intervention on a wide scale. Despite the popularity of publicly available physical activity (PA) apps, little is known about their effectiveness. This study aimed to investigate the potential of the apps to increase PA. The objectives were: 1) to determine the feasibility of the trial, 2) explore the effects of the apps on behavioural and psychological outcomes

Methods

Feasibility randomised crossover trial of two popular apps. Inactive adults residing in London (UK) were eligible. The two interventions were: App A - 7 Minute Workout Challenge by Fitness Guide Inc., App B - One You Couch to 5k by Public Health England. After 1-week run-in period, participants were randomly allocated to one of the two assessment sequence (App A, B or App B, A).

Results

Out of 104 participants who were eligible and consented, 63.5% (66/104) were enrolled and randomised. The primary analysis of the accelerometer data showed that there were no significant differences between baseline and the interventions using the continuous variables. Sixteen of 51 participants (31.4%) increased their time in moderate to vigorous PA (MVPA) by 20% from baseline following the introduction of the intervention (95% CI = 19.1% to 45.39). Self-reported PA outcomes showed significant increase and sedentary behaviour decreased. Exercise self-efficacy and intentions increased whilst PA outcome expectancy decreased.

Conclusions

The impact of this two PA apps showed promising results with an impact observed for 20% increase in MVPA, self-reported PA, intentions and exercise self-efficacy. Yet, there was a variability in the outcomes observed.

Key messages

This pragmatic trial with participants classed as inactive showed that physical activity apps can increase physical activity. There was a variability of the physical activity outcome and there is a need to tailor digital tools to the users to impact physical activity on a wide scale.

Early Warning Scores do not accurately predict mortality in sepsis: A meta-analysis and systematic review of the literature

OBJECTIVES

Early Warning Scores are used to evaluate patients in many hospital settings. It is not clear if these are accurate in predicting mortality in sepsis. We performed a systematic review and meta-analysis of multiple studies in sepsis. Our aim was to estimate the accuracy of EWS for mortality in this setting.

METHODS

PubMED, CINAHL, Cochrane, Web of Science and EMBASE were searched to October 2016. Studies of adults with sepsis who had EWS calculated using any appropriate tool (e.g. NEWS, MEWS) were eligible for inclusion. Study quality was assessed using QUADAS-2. Summary estimates were derived using HSROC analysis.

RESULTS

Six studies (4298 participants) were included. Results suggest that EWS cannot be used to predict which patients with sepsis will (positive likelihood ratio 1.79, 95% CI 1.53 to 2.11) or will not die (negative likelihood ratio 0.59, 95% CI 0.45 to 0.78). Two studies were rated as low risk of bias and one as unclear risk of bias on all domains. The other three studies were judged at high risk of bias in one domain.

CONCLUSION

Early Warning Scores are not sufficiently accurate to rule in or rule out mortality in patients with sepsis, based on the evidence available, which is generally poor quality.

Nausea and vomiting in gastroparesis: similarities and differences in idiopathic and diabetic gastroparesis

BACKGROUND

Nausea and vomiting are classic symptoms of gastroparesis. It remains unclear if characteristics of nausea and vomiting are similar in different etiologies of gastroparesis. The aims of this article were as follows: to describe characteristics of nausea and vomiting in patients with gastroparesis and to determine if there are differences in nausea and vomiting in diabetic (DG) and idiopathic gastroparesis (IG).

METHODS

Gastroparetic patients enrolling in the NIDDK Gastroparesis Registry underwent assessment with history and questionnaires assessing symptoms, quality of life, and a questionnaire characterizing nausea and vomiting.

KEY RESULTS

Of 159 gastroparesis patients (107 IG, 52 DG), 96% experienced nausea, whereas 65% experienced vomiting. Nausea was predominant symptom in 28% and vomiting was predominant in 4%. Nausea was severe or very severe in 41%. PAGI-SYM nausea/vomiting subscore was greater with increased vomiting severity, but not nausea severity in DG than IG. Nausea was related to meals in 71%; lasting most of the day in 41%. Increasing nausea severity was related to decreased quality of life. Nausea often preceded vomiting in 82% of patients and vomiting often relieved nausea in 30%. Vomiting was more common in DG (81%) compared to IG (57%; p = 0.004). Diabetic patients more often had vomiting in the morning before eating, during the night, and when not eating.

CONCLUSIONS & INFERENCES

Nausea is present in essentially all patients with gastroparesis irrespective of cause and associated with decreased quality of life. In contrast, vomiting was more prevalent, more severe, and occurred more often in DG than IG. Thus, characteristics of vomiting differ in IG vs DG.

Factors related to abdominal pain in gastroparesis: contrast to patients with predominant nausea and vomiting

BACKGROUND

Factors associated with abdominal pain in gastroparesis are incompletely evaluated and comparisons of pain vs other symptoms are limited. This study related pain to clinical factors in gastroparesis and contrasted pain/discomfort- with nausea/vomiting-predominant disease.

METHODS

Clinical and scintigraphy data were compared in 393 patients from seven centers of the NIDDK Gastroparesis Clinical Research Consortium with moderate-severe (Patient Assessment of Upper Gastrointestinal Disorders Symptoms [PAGI-SYM] score ≥ 3) vs none-mild (PAGI-SYM < 3) upper abdominal pain and predominant pain/discomfort vs nausea/vomiting.

KEY RESULTS

Upper abdominal pain was moderate-severe in 261 (66%). Pain/discomfort was predominant in 81 (21%); nausea/vomiting was predominant in 172 (44%). Moderate-severe pain was more prevalent with idiopathic gastroparesis and with lack of infectious prodrome (P ≤ 0.05) and correlated with scores for nausea/vomiting, bloating, lower abdominal pain/discomfort, bowel disturbances, and opiate and antiemetic use (P < 0.05), but not gastric emptying or diabetic neuropathy or control. Gastroparesis severity, quality of life, and depression and anxiety were worse with moderate-severe pain (P ≤ 0.008). Factors associated with moderate-severe pain were similar in diabetic and idiopathic gastroparesis. Compared to predominant nausea/vomiting, predominant pain/discomfort was associated with impaired quality of life, greater opiate, and less antiemetic use (P < 0.01), but similar severity and gastric retention.

CONCLUSIONS & INFERENCES

Moderate-severe abdominal pain is prevalent in gastroparesis, impairs quality of life, and is associated with idiopathic etiology, lack of infectious prodrome, and opiate use. Pain is predominant in one fifth of gastroparetics. Predominant pain has at least as great an impact on disease severity and quality of life as predominant nausea/vomiting.

Loneliness and cognition in older people: the Dublin Healthy Ageing study

INTRODUCTION

While several studies have found a link between impaired cognition and social isolation, few have examined the relationship between cognition and loneliness. Loneliness has been thought to increase the risk of development of Alzheimer's dementia.

AIM

The aims of this study were to explore the relationship between loneliness and cognition and to determine whether specific cognitive domains are associated with loneliness.

DESIGN

Cross-sectional community-based study.

PARTICIPANTS

This study included 466 community-dwelling subjects with mean age 75.45 (SD 6.06) years, of which 208(44%) were males.

RESULTS

Loneliness was significantly associated with impaired global cognition independent of social networks and depression. The domains of psychomotor processing speed and delayed visual memory were specifically associated with self-reported loneliness.

CONCLUSION

This cross-sectional study demonstrated an association between loneliness and specific aspects of cognition independent of depression, social networks and other demographics. The mechanism for this association is unclear and warrants further investigation.

Loneliness and vascular biomarkers: the Dublin Healthy Ageing Study

BACKGROUND

Loneliness has been associated with poor physical health and a link has been suggested between the presence of loneliness, cardiovascular health and inflammatory markers.

OBJECTIVE

To investigate the association between vascular disease biomarkers and loneliness in a community-dwelling non-demented elderly population.

DESIGN

cross-sectional community based assessment.

PARTICIPANTS

466 subjects with mean age 75.45 (SD, 6.06) years. 208 (44.6%) were male.

RESULTS

Higher levels of HbA1c, but not other vascular biomarkers were independently associated with being lonely.

CONCLUSION

Loneliness was associated with raised levels of HbA1c in a community dwelling elderly population. The mechanism for this association has yet to be elucidated but may reflect an abnormal stress response in people who are lonely.

Associations between holotranscobalamin, vitamin B12, homocysteine and depressive symptoms in community-dwelling elders

BACKGROUND

Vitamin B12 and homocysteine have been shown to be associated with depression or depressive symptoms, but the relationship has not been universal. Both vitamin B12 and homocysteine may exert an effect via vascular mechanisms; it is possible that other mechanisms apply. Holotranscobalamin is a novel, more accurate measure of tissue vitamin B12.

OBJECTIVES

To examine associations between vitamin B12, serum folate, holotranscobalamin, homocysteine and depressive symptoms in a sample of healthy elderly.

METHODS

Cross-sectional, observational community based study.

RESULTS

Lower levels of holotranscobalamin and vitamin B12 were associated with higher levels of depressive symptoms when controlled for Mini-mental state examination scores and psychosocial and cardiovascular risk factors. Homocysteine was not associated with depressive symptoms when biological and psychosocial covariates were included.

CONCLUSIONS

It is possible that low levels of vitamin B12 or holotranscobalamin are associated with depressive symptoms via mechanisms other than vascular pathology.

Vitamin B12 status, homocysteine and mortality amongst community-dwelling Irish elders

BACKGROUND

Vitamin B12 deficiency is associated with hyperhomocysteinaemia, which is associated with atherosclerosis and increased mortality. High levels of vitamin B12 have also been associated with increased mortality in certain patient populations.

AIMS

We examined vitamin B12 and homocysteine status and mortality rates in a population of Irish community-dwelling elders over a 3-year period.

METHODS

Prospective, community-based observational cohort study.

RESULTS

Subjects in the highest quartile of homocysteine had increased mortality rates (14.68 vs. 7.32%, relative risk 2.09). This relationship was attenuated when controlled for the presence or absence of a history of stroke or myocardial infarction. There was no relationship between vitamin B12 status and mortality during the observation period.

CONCLUSION

Vitamin B12 levels are not associated with death rates in Irish community-dwelling elders. Homocysteine levels are associated with mortality and may act via the mechanism of atherosclerotic disease.

Gastroparesis and functional dyspepsia: excerpts from the AGA/ANMS meeting

BACKGROUND

Despite the relatively high prevalence of gastroparesis and functional dyspepsia, the aetiology and pathophysiology of these disorders remain incompletely understood. Similarly, the diagnostic and treatment options for these two disorders are relatively limited despite recent advances in our understanding of both disorders.

PURPOSE

This manuscript reviews the advances in the understanding of the epidemiology, pathophysiology, diagnosis, and treatment of gastroparesis and functional dyspepsia as discussed at a recent conference sponsored by the American Gastroenterological Association (AGA) and the American Neurogastroenterology and Motility Society (ANMS). Particular focus is placed on discussing unmet needs and areas for future research.

Walking and talking: an investigation of cognitive-motor dual tasking in multiple sclerosis

BACKGROUND

Deficits in motor functioning, including walking, and in cognitive functions, including attention, are known to be prevalent in multiple sclerosis (MS), though little attention has been paid to how impairments in these areas of functioning interact.

OBJECTIVES

This study investigated the effects of performing a concurrent cognitive task when walking in people with MS. Level of task demand was manipulated to investigate whether this affected level of dual-task decrement.

METHOD

Eighteen participants with MS and 18 healthy controls took part. Participants completed walking and cognitive tasks under single- and dual-task conditions.

RESULTS

Compared to healthy controls, MS participants showed greater decrements in performance under dual-task conditions in cognitive task performance, walking speed and swing time variability. In the MS group, the degree of decrement under dual-task conditions was related to levels of fatigue, a measure of general cognitive functioning and self-reported everyday cognitive errors, but not to measures of disease severity or duration.

CONCLUSIONS

Difficulty with walking and talking in MS may be a result of a divided attention deficit or of overloading of the working memory system, and further investigation is needed. We suggest that difficulty with walking and talking in MS may lead to practical problems in everyday life, including potentially increasing the risk of falls. Clinical tools to assess cognitive-motor dual-tasking ability are needed.

Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs

OBJECTIVE

To determine whether previously described advanced blastocyst development and high implantation rates are confirmed in an expanded multicenter trial.

DESIGN

Retrospective review.

SETTING

Two private assisted reproductive technology units.

PATIENT(S)

One hundred seventy-four patients who underwent blastocyst culture and transfer.

INTERVENTION(S)

Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5) followed by ET.

MAIN OUTCOME MEASURE(S)

The number and percentage of blastocysts developed, implantation rates, pregnancy rates, and parameters that affected outcome were analyzed.

RESULT(S)

Only 3 of 174 patients failed to achieve blastocyst-stage ET. The mean blastocyst development rate was 48%. The ongoing pregnancy rate was 66.3% per oocyte retrieval, with a mean (+/-SE) of 2.2 +/- 0.05 blastocysts transferred and an implantation rate of 48% per blastocyst transferred.

CONCLUSION(S)

Blastocyst culture and transfer is an effective means of treating patients who respond well to gonadotropins. High pregnancy rates can be accomplished with low numbers of embryos transferred. Patients who failed to achieve ET were rare.

Capitation and insurance protection: how to protect against unpredictability

Capitation contracting has created new challenges in the world of health care. The payment emphasis in a capitated environment concentrates on prepayment of services. Opportunities are created to control health care dollars by the physician or hospital group, but the potential downside must also be recognized. This article introduces the Provider Excess Loss (or "stop loss") insurance product and some of the main features of coverage. This insurance is specifically designed to protect providers in a capitated environment and is purchased by Physician Hospital Organizations (PHO), Independent Physician Associations (IPA), and physician-owned HMOs, among others. The emphasis is on collective purchasing. Focus on the main policy features-deductible options, allowable charges, and premium factors-should ensure a basic understanding of how coverage works and how to design coverage to make it fit the unique needs of each provider's risk.

Assisted hatching reduces the age-related decline in IVF outcome in women younger than age 43 without increasing miscarriage or monozygotic twinning

PURPOSE

Our purpose was to examine the benefits of assisted hatching in our program and to determine whether the procedure increases the implantation of nonviable embryos or monozygotic twinning.

METHODS

Consecutive in vitro fertilization cycles using assisted hatching were compared with historical controls. The impact of assisted hatching was analyzed according to the woman's age. Outcome measures were clinical pregnancy, implantation rate, delivery rate, multiple pregnancy, spontaneous abortion, and incidence of monozygotic twins.

RESULTS

The implantation rate was increased in women aged 35-39 and markedly increased in women aged 40-42. There was no change in spontaneous abortions and no increase in monozygotic twins.

CONCLUSIONS

Assisted hatching is a safe and highly effective adjunct to in vitro fertilization for women aged 35-42 and did not increase spontaneous abortion or monozygotic twinning.

Successful pregnancies with unstimulated cycle oocyte donation using an antagonist of gonadotropin-releasing hormone

We achieved two ongoing pregnancies in five older recipients with natural cycle oocyte donation from five young donors using a GnRH antagonist, with hMG and hCG to complete oocyte maturation. This provides a new alternative to ovarian stimulation for both oocyte donation and routine IVF.

Genetic basis for diabetes resistance in NOD/Wehi mice

The basis for diabetes resistance in low diabetes incidence NOD/Wehi mice was examined in a breeding study. NOD/Wehi mice were crossed with high diabetes incidence NOD/Lt mice producing F1 hybrid mice which expressed a low incidence of diabetes. To distinguish between genetic and environmental causes for diabetes resistance, these F1 mice were backcrossed to NOD/Lt mice resulting in BC1 hybrid mice which expressed an intermediate incidence of diabetes. Similar results were obtained by examining the severity of insulitis in the hybrid mice. As both the incidence of diabetes and severity of insulitis in the hybrid mice were consistent with a single dominant gene mediating diabetes resistance, an attempt to localize this gene was made. Although over 140 loci which display polymorphism amongst inbred strains were typed in both parental lines, only a single locus, D8Mit9, was found to differ. As heterozygotes at D8Mit9 were not over represented amongst 45 diabetic BC1 hybrid mice examined, it was concluded that a resistance gene was not linked to this locus.

Leuprolide acetate elevates prolactin during ovarian stimulation with gonadotropins

OBJECTIVE

The purpose of this study was to determine whether gonadotropin-releasing hormone agonist further increases the prolactin rise accompanying ovarian stimulation.

DESIGN

Serum prolactin concentrations were compared between cycles with and cycles without the use of leuprolide acetate (LA) matched for estradiol levels. Relationships of prolactin levels to cycle outcomes were examined.

SETTING

The study took place at a private fertility center.

PATIENTS

Patients were women receiving stimulation for oocyte retrieval using human menopausal gonadotropins.

INTERVENTIONS

No interventions were used.

MAIN OUTCOME MEASURES

Serum prolactin level, fertilization rate, embryo quality, and pregnancy were the main outcome measures.

RESULTS

Higher serum prolactin was associated with both higher estradiol levels and use of LA but did not have any effects on fertilization rate, embryo quality, or occurrence of pregnancy.

CONCLUSION

LA stimulates prolactin release during ovarian stimulation but without apparent consequence.

Impaired Uterine Receptivity in Infertile Women over Age 40 having Oocyte Donation and Correction with Increased Progesterone Replacement

Significantly fewer ongoing and delivered pregnancies occurred in infertile women aged >40 years receiving oocyte donation from young normal women (8%, P<0.02) than in a similar group of younger recipients receiving identical treatment (43%). A significant improvement (46Yo ongoing and delivered, P<0.01) was achieved in another group of women over 40, treated with a doubled dose of progesterone. The results are consistent with those observed in animal studies and suggest an effect of ageing on uterine receptivity that is at least partly correctable by augmented progesterone stimulation of the endometrium.

Percutaneous implantation of a balloon-expandable endoprosthesis for pulmonary artery stenosis: an experimental study

Conventional therapy to treat peripheral pulmonary artery stenosis (surgery or balloon angioplasty) has been frustrating. Recently a variety of peripheral vascular stenoses, in which conventional approaches are disappointing, have become amenable to therapy with the use of a balloon-expandable endovascular stent. This experimental study was designed to assess the application of such a prosthesis in artificially created pulmonary artery stenoses. In 9 of 12 2-week old pigs, left pulmonary artery stenosis was surgically created (3.9 +/- 1.1 mm diameter and 7 +/- 1 mm Hg mean gradient). At 6.8 +/- 1 weeks of age (13 +/- 4 kg), percutaneous (femoral venous) implantation of a 3-cm long balloon-expandable (maximal diameter 18 mm) stent (three placed into normal pulmonary artery branches) using a 3-cm x 10-mm balloon dilating catheter was achieved without technical difficulties. Stenoses were enlarged to 8.3 +/- 1.4 mm with a decrease in mean gradient to 1 +/- 1 mm Hg that was maintained through 3.5 months of follow-up. Histologic and electron micrographic studies identified normal-appearing neoendothelial layering over stent struts without intraluminal or peripheral thrombus formation and nonobstructed side branching to lung subsegments. These findings support the application of this approach in the treatment of pulmonary stenosis that is not amenable to conventional therapy.

Lower pregnancy rate with premature luteinization during pituitary suppression with leuprolide acetate

The relationship of the circulating level of progesterone (P) on the day of human chorionic gonadotropin (hCG) injection to occurrence of clinical pregnancy was examined in 133 leuprolide acetate human menopausal gonadotropin (hMG) in vitro fertilization cycles in women having at least three embryos transferred. Progesterone concentrations greater than 0.5 ng/mL were associated with a significantly lower rate of pregnancy (12/59, 20%) compared with less than 0.5 ng/mL (40/74, 54%, P less than 0.005). The higher P cycles were associated with greater patient age and hMG dose, although these relationships appeared to be indirect. Luteinizing hormone (LH) concentrations remained suppressed. Ovarian stimulation may cause excessive luteinization and an adverse cycle outcome even in the presence of low LH levels. Prospective use of P levels may be helpful to determine optimal hCG timing.

Spatial correlation between thyroid epithelial cells expressing class II MHC molecules and interferon-gamma-containing lymphocytes in human thyroid autoimmune disease

In this immunohistochemical study we addressed the question whether aberrant class II MHC expression by thyroid epithelial cells (thyrocytes) in established thyroid autoimmune disease is the result of release of interferon-gamma (IFN-gamma) by adjacent lymphocytes. Thyroids from eight cases of Hashimoto's thyroiditis, 13 cases of Graves' disease and 10 cases of focal thyroiditis were studied. Both thyrocytes expressing class II MHC and lymphocytes containing immunoreactive IFN-gamma were found in all 31 autoimmune thyroids. In a serial section study of these thyroids, IFN-gamma-expressing lymphocytes were found within 50 microns of class II MHC-positive thyrocytes in 89% of 282 randomly selected fields. Conversely, class II MHC-positive thyrocytes were found within 50 micron of aggregates of IFN-gamma-positive lymphocytes in 82% of 272 randomly selected fields. These findings support the view that in established thyroid autoimmune disease expression of class II MHC by thyrocytes is the result of local release of IFN-gamma.

Effects of low perfusate Ca2+ concentration on newborn myocardial function after ischemia

A greater dependence on transsarcolemmal Ca2+ flux and immaturity of Ca2+ sequestration capacity may potentiate Ca2(+)-mediated reperfusion injury in the newborn myocardium. The effect of serum ionized Ca2+ concentration on left ventricular systolic and diastolic function after ischemia was studied in 5-7-day-old piglets undergoing a 90-minute period of cold-blood cardioplegic arrest. In the control group, Ca2+ was maintained at 1.2 mM (Group A [n = 6]). The cardioplegic solution and bypass perfusate were modified to achieve a low Ca2+ concentration, 0.25 mM, in Group B (n = 6). Left ventricular pressure-volume loops were acquired by using high-fidelity pressure-sensor-tipped and volume-conductance catheters. Ventricular function was assessed from the slope of end-systolic (Ees) and end-diastolic (k) pressure-volume relations during transient caval occlusion. Both groups showed a significant reduction in Ees after ischemia (p less than 0.05). Intergroup comparison of Ees after ischemia demonstrated a better recovery of the systolic function in the low Ca2+ group, 64 +/- 7% versus 49 +/- 6% in the normal Ca2+ group (p = 0.05). There was a significant increase in chamber stiffness index in group A (k, 0.48 +/- 0.06 to 0.65 +/- 0.05 ml-1, p less than 0.01) versus no significant change in group B. This study shows 1) the feasibility of acquiring continuous pressure-volume data in neonatal hearts by using a conductance catheter system, and 2) better preservation of systolic function and diastolic compliance in normal newborn myocardium by low Ca2+ concentration in the peri-ischemic period.

Neonatal autoperfused working heart-lung preparation: assessment of factors determining survival

The function and survival of the autoperfused working heart-lung preparation in the newborn period was studied in six newborn pigs (3 to 5 days old). Normothermic autoperfusion was maintained by a closed blood-primed circuit. Left ventricular afterload was determined by positioning the blood reservoir, and the venous return was adjusted to maintain a right atrial pressure of 6 to 8 mm Hg. Left ventricular function was assessed by a conductance catheter in the left ventricle and was determined by the slope of the end-systolic pressure-volume relationship. Left ventricular diastolic compliance was measured from the end-diastolic pressure-volume relationship. Serial measurements at 60, 120, 180, and 240 minutes showed no change in the end-systolic pressure-volume relationship, whereas there was a significant leftward shift of the end-diastolic pressure-volume relationship after 240 minutes (0.42 +/- 0.02 ml-1 to 0.66 +/- 0.04 ml-1, p less than 0.05). Cessation of effective cardiac function occurred at 268 +/- 10 minutes (+/- SEM). This followed progressive deterioration in pulmonary function based on measurement of arterial blood gases and peak airway resistance. This study shows the feasibility of maintaining systolic cardiac function in a newborn autoperfused working heart-lung preparation. Extended survival beyond 4 hours will require improved methods to preserve left ventricular diastolic function and especially pulmonary function.

Leuprolide acetate lowers circulating bioactive luteinizing hormone and testosterone concentrations during ovarian stimulation for oocyte retrieval

Levels of immunoreactive luteinizing hormone (LH), bioactive LH, and testosterone (T) were determined in 52 women receiving human menopausal gonadotropins (hMG). In 26 women receiving leuprolide acetate (LA) preceding hMG, there was a significant suppression of immunoreactive LH and bioactive LH. The characteristic increase in serum levels of bioactive LH and T were absent. Follicular fluid estradiol and T concentrations, and serum progesterone were not different. The lower circulating levels of T may reflect reduced LH-stimulated androgen accumulation in smaller nonaspirated follicles and may account for the enhanced follicle recruitment observed during LA. The lack of premature luteinization despite marked rises of bioactive LH in the absence of LA is consistent with normal events during the menstrual cycle and was due to the early termination of hMG stimulation.

Normal fertilization in men with high antibody sperm binding by the addition of sufficient unbound sperm in vitro

A high incidence of fertilization failure has been reported in men with over 70% of their sperm bound with isoantibodies. In three men with greater than 80% antisperm antibody binding with IgG and IgA immunoglobulins, a normal rate of fertilization (29/46 oocytes; 63%) was achieved by adding a sufficient number of motile sperm to provide at least 50,000 unbound sperm per oocyte. This method appears to be simpler and more effective than attempting to separate unbound sperm in vitro.

Routine pituitary suppression with leuprolide before ovarian stimulation for oocyte retrieval

Pituitary suppression with leuprolide acetate (LA) was used before and during ovarian stimulation with human menopausal gonadotropins in 45 consecutive women having their first cycle of in vitro fertilization embryo transfer (IVF-ET). As anticipated, a low rate of cycle cancellation (6.7%) was necessary for poor responses. Follicles were allowed to develop to a larger diameter than with our prior protocol without LA. On the day of human chorionic gonadotropin (hCG), 11.5 + 0.7 follicles of at least 1.0 cm were visualized; 11.7 + 0.9 oocytes were retrieved; 67.5% fertilized and 6.7 + 0.6 normal embryos were available for transfer. Of the 3.4 + 0.1 embryos transferred per patient, 24.6% implanted. The rates of clinical pregnancy per retrieval and per stimulation were 54% and 47%, respectively, of which 23.8% aborted. Routine use of LA resulted in a highly efficient level of ongoing pregnancy per initiated cycle, and therefore may produce a superior first cycle for IVF-ET.

1-(3-cyano-2,3-dideoxy-beta-D-erythro-pentofuranosyl)thymine (cyanothymidine): synthesis and antiviral evaluation against human immunodeficiency virus

1-(3-Cyano-2,3-dideoxy-beta-D-erythro-pentofuranosyl)thymine (cyanothymidine) (3a) has been prepared by an unambiguous route starting from D-xylose. The relative and absolute stereochemistry of 3a and its anomeric isomer 9 have been confirmed by NOE experiments and by X-ray diffraction analysis. In antiviral tests vs HIV 3a was shown to be inactive, a surprising result in view of a preliminary disclosure claiming potent anti-HIV activity. The activity previously assigned to 3a is believed to be due to contamination of that sample with the known antiviral nucleoside analogue 5b.