Ceftazidime-Avibactam Improves Outcomes in High-Risk Neutropenic Patients with Klebsiella pneumoniae Carbapenemase-Producing Enterobacterales Bacteremia

Few studies have evaluated the efficacy of ceftazidime-avibactam (CA) for Klebsiella pneumoniae carbapenemase-producing Enterobacterales bacteremia (KPC-PEB) in high-risk neutropenic patients. This is a prospective multicenter observational study in high-risk neutropenic patients with multi-drug resistant Enterobacterales bacteremia. They were compared according to the resistance mechanism and definitive treatment provided: KPC-CPE treated with CA (G1), KPC-CPE treated with other antibiotics (G2), and patients with ESBL-producing Enterobacterales bacteremia who received appropriate definitive therapy (G3). Thirty-day mortality was evaluated using a logistic regression model, and survival was analyzed with Kaplan-Meier curves. A total of 238 patients were included: 18 (G1), 52 (G2), and 168 (G3). Klebsiella spp. (60.9%) and Escherichia coli (26.4%) were the Enterobacterales most frequently isolated, and 71% of the bacteremias had a clinical source. The resistance profile between G1 and G2 was colistin 35.3% vs. 36.5%, amikacin 16.7% vs. 40.4%, and tigeclycline 11.1% vs. 19.2%. The antibiotics prescribed in combination with G2 were carbapenems, colistin, amikacin, fosfomycin, tigecycline, and fluoroquinolones. Seven-day clinical response in G1 vs. G2 vs. G3 was 94.4% vs. 42.3% vs. 82.7%, respectively (p < 0.001). Thirty-day overall mortality in G1 vs. G2 vs. G3 was 22.2% vs. 53.8% vs. 11.9%, respectively (p < 0.001), and infection-related mortality was 5.5% vs. 51.9% vs. 7.7% (p < 0.001). The independent risk factors for mortality were Pitt score > 4: OR 3.63, 95% CI, 1.18-11.14 (p = 0.025) and KPC-PEB treated with other antibiotics: OR 8.85, 95% CI, 2.58-30.33 (p = 0.001), while 7-day clinical response was a protective factor for survival: OR 0.02, 95% CI, 0.01-0.08 (p < 0.001). High-risk neutropenic patients with KPC-CPE treated with CA had an outcome similar to those treated for ESBL-producing Enterobacterales, with higher 7-day clinical response and lower overall and infection-related mortality than those treated with other antibiotics. In view of these data, CA may be considered the preferred therapeutic option for KPC-PEB in high-risk neutropenic patients.

Development of a Clinical Score to Stratify the Risk for Carbapenem-Resistant Enterobacterales Bacteremia in Patients with Cancer and Hematopoietic Stem Cell Transplantation

Identifying the risk factors for carbapenem-resistant Enterobacterales (CRE) bacteremia in cancer and hematopoietic stem cell transplantation (HSCT) patients would allow earlier initiation of an appropriate empirical antibiotic treatment. This is a prospective multicenter observational study in patients from 12 centers in Argentina, who presented with cancer or hematopoietic stem-cell transplant and developed Enterobacterales bacteremia. A multiple logistic regression model identified risk factors for CRE bacteremia, and a score was developed according to the regression coefficient. This was validated by the bootstrap resampling technique. Four hundred and forty-three patients with Enterobacterales bacteremia were included: 59 with CRE and 384 with carbapenem-susceptible Enterobacterales (CSE). The risk factors that were identified and the points assigned to each of them were: ≥10 days of hospitalization until bacteremia: OR 4.03, 95% CI 1.88-8.66 (2 points); previous antibiotics > 7 days: OR 4.65, 95% CI 2.29-9.46 (2 points); current colonization with KPC-carbapenemase-producing Enterobacterales: 33.08, 95% CI 11.74-93.25 (5 points). With a cut-off of 7 points, a sensitivity of 35.59%, specificity of 98.43%, PPV of 77.7%, and NPV of 90.9% were obtained. The overall performance of the score was satisfactory (AUROC of 0.85, 95% CI 0.80-0.91). Finally, the post-test probability of CRE occurrence in patients with none of the risk factors was 1.9%, which would virtually rule out the presence of CRE bacteremia.

Deleterious and Protective Psychosocial and Stress-Related Factors Predict Risk of Spontaneous Preterm Birth

OBJECTIVES

The aim of the study was to: (1) Identify (early in pregnancy) psychosocial and stress-related factors that predict risk of spontaneous preterm birth (PTB, gestational age <37 weeks); (2) Investigate whether "protective" factors (e.g., happiness/social support) decrease risk; (3) Use the Dhabhar Quick-Assessment Questionnaire for Stress and Psychosocial Factors (DQAQ-SPF) to rapidly quantify harmful or protective factors that predict increased or decreased risk respectively, of PTB.

STUDY DESIGN

This is a prospective cohort study. Relative risk (RR) analyses investigated association between individual factors and PTB. Machine learning-based interdependency analysis (IDPA) identified factor clusters, strength, and direction of association with PTB. A nonlinear model based on support vector machines was built for predicting PTB and identifying factors that most strongly predicted PTB.

RESULTS

Higher levels of deleterious factors were associated with increased RR for PTB: General anxiety (RR = 8.9; 95% confidence interval [CI] = 2.0,39.6), pain (RR = 5.7; CI = 1.7,17.0); tiredness/fatigue (RR = 3.7; CI = 1.09,13.5); perceived risk of birth complications (RR = 4; CI = 1.6,10.01); self-rated health current (RR = 2.6; CI = 1.0,6.7) and previous 3 years (RR = 2.9; CI = 1.1,7.7); and divorce (RR = 2.9; CI = 1.1,7.8). Lower levels of protective factors were also associated with increased RR for PTB: low happiness (RR = 9.1; CI = 1.25,71.5); low support from parents/siblings (RR = 3.5; CI = 0.9,12.9), and father-of-baby (RR = 3; CI = 1.1,9.9). These factors were also components of the clusters identified by the IDPA: perceived risk of birth complications (p < 0.05 after FDR correction), and general anxiety, happiness, tiredness/fatigue, self-rated health, social support, pain, and sleep (p < 0.05 without FDR correction). Supervised analysis of all factors, subject to cross-validation, produced a model highly predictive of PTB (AUROC or area under the receiver operating characteristic = 0.73). Model reduction through forward selection revealed that even a small set of factors (including those identified by RR and IDPA) predicted PTB.

CONCLUSION

These findings represent an important step toward identifying key factors, which can be assessed rapidly before/after conception, to predict risk of PTB, and perhaps other adverse pregnancy outcomes. Quantifying these factors, before, or early in pregnancy, could identify women at risk of delivering preterm, pinpoint mechanisms/targets for intervention, and facilitate the development of interventions to prevent PTB.

KEY POINTS

· Newly designed questionnaire used for rapid quantification of stress and psychosocial factors early during pregnancy.. · Deleterious factors predict increased preterm birth (PTB) risk.. · Protective factors predict decreased PTB risk..

Revealing the impact of lifestyle stressors on the risk of adverse pregnancy outcomes with multitask machine learning

Psychosocial and stress-related factors (PSFs), defined as internal or external stimuli that induce biological changes, are potentially modifiable factors and accessible targets for interventions that are associated with adverse pregnancy outcomes (APOs). Although individual APOs have been shown to be connected to PSFs, they are biologically interconnected, relatively infrequent, and therefore challenging to model. In this context, multi-task machine learning (MML) is an ideal tool for exploring the interconnectedness of APOs on the one hand and building on joint combinatorial outcomes to increase predictive power on the other hand. Additionally, by integrating single cell immunological profiling of underlying biological processes, the effects of stress-based therapeutics may be measurable, facilitating the development of precision medicine approaches.

OBJECTIVES

The primary objectives were to jointly model multiple APOs and their connection to stress early in pregnancy, and to explore the underlying biology to guide development of accessible and measurable interventions.

MATERIALS AND METHODS

In a prospective cohort study, PSFs were assessed during the first trimester with an extensive self-filled questionnaire for 200 women. We used MML to simultaneously model, and predict APOs (severe preeclampsia, superimposed preeclampsia, gestational diabetes and early gestational age) as well as several risk factors (BMI, diabetes, hypertension) for these patients based on PSFs. Strongly interrelated stressors were categorized to identify potential therapeutic targets. Furthermore, for a subset of 14 women, we modeled the connection of PSFs to the maternal immune system to APOs by building corresponding ML models based on an extensive single cell immune dataset generated by mass cytometry time of flight (CyTOF).

RESULTS

Jointly modeling APOs in a MML setting significantly increased modeling capabilities and yielded a highly predictive integrated model of APOs underscoring their interconnectedness. Most APOs were associated with mental health, life stress, and perceived health risks. Biologically, stressors were associated with specific immune characteristics revolving around CD4/CD8 T cells. Immune characteristics predicted based on stress were in turn found to be associated with APOs.

CONCLUSIONS

Elucidating connections among stress, multiple APOs simultaneously, and immune characteristics has the potential to facilitate the implementation of ML-based, individualized, integrative models of pregnancy in clinical decision making. The modifiable nature of stressors may enable the development of accessible interventions, with success tracked through immune characteristics.

945. Bacteremia in Patients with Solid Tumors: Epidemiology, Clinical Features and Risk Factors for Mortality. Results from a Multicenter Study in Argentina

Background

Current information regarding bacteriemia in patients with solid tumors is scarce

Methods

To assess the etiology, clinical features and outcome in patients with solid tumors and bacteremia, we carried out a prospective multicenter study. Episodes of bacteriemia in adult cancer patients in 9 centers, from May 2014 to February 2021, were recorded. To identify factors associated with 30-day mortality, variables with p &lt; 0.05 in univariate analysis were included in a logistic regression model for multivariate analysis

Results

Three hundred and thirty-two episodes of bacteremia were included, with 51% being women (mean age 59). The state of underlying disease was: recent diagnosis 27%, remission 27%, relapsed 29% and refractory 17%. Seventy-three percent had received chemotherapy in the last 30 days, 25% were receiving steroids. Neutropenia was present in 23% (mean duration 3 days). The most frequent sources were: abdominal 39%, urinary tract 21%, respiratory 15%, catheter 10% and skin and soft tissue 9%. The microorganisms were: Gram negative bacilli (GNB) 67% (Enterobacterales 84%), Gram positive cocci 36% (Staphylococcus aureus 33%) and polimicorbial 11%; 20% were multidrug resistant organisms (MDR-O), being 88% of them GNB (MDR-GNB). ESBL and KPC carbapenemase producing were the most frequent mechanisms of resistance. Mortality at day 7 and day 30 was 16% and 27%, respectively. In the univariate analysis, the risk factors for 30-day mortality were Charlson index, refractory underlying disease, use of steroids, polimicrobial bacteremia, Staphylococcus aureus, GNB resistant to carbapenems, APACHE and Pitt scores, hypotension, respiratory source and ICU admission. In multivariate analysis, risk factors for 30-day mortality were refractory underlying disease, GNB resistant to carbapenems and ICU admission, while 7-day clinical response was associated with lower mortality

Conclusion

Bacteremia is a serious complication in cancer patients, with high mortality. The state of underlying disease, infection caused by GNB resistant to carbapenems, and the severity of presentation are associated with increased mortality. Our results stress the importance of infection control measures and antibiotic stewardship to prevent colonization with MDR-O

Disclosures

All Authors: No reported disclosures

Strategic methodology to set priorities for sustainable hydropower development in a biodiversity hotspot

Massive exploitation of freshwater systems for hydropower generation in developing countries is challenging sustainability due to cumulative environmental impacts in regions with high endemism. Habitat fragmentation is recognized as a major impact on river ecosystems. The nature and magnitude of connectivity loss depend on characteristics of the hydropower projects, and of the threatened fish communities. In areas where appropriate mitigation technology is lacking, there is a need to identify the fish species that are most at risk to better concentrate efforts. This paper aimed to set conservation priorities for sustainable hydropower development by analyzing native fish species and project characteristics. The Chilean ichthyogeographic province, an ecoregion with high endemism and massive hydropower projects development, has been considered as a case study. By using overlapping information on the characteristics of 1124 hydropower projects and distribution of native fish species, we identified three project categories of projects based on their need for mitigation. These were projects where mitigation was considered: a) not required (15%), b) required and feasible (35%), and c) required but challenging (50%). Projects where mitigation was not required were located at sites where native fish were absent and/or where water intakes allowed fish to pass. Interestingly, projects where mitigation was feasible were inhabited by a species assemblage that comprised the genus Trichomycterus, Diplomystes and Percilia, and the species Ch. pisciculus and B. maldonadoi. This finding emphasizes the need to develop a multispecific fishway that can accommodate this group. Projects where mitigation would be difficult to achieve were located at sites with a variety of different assemblages, thus making a standard fish pass solution challenging and site-specific. This study advances understanding for the need to develop mitigation strategies and technologies in ecoregions of high endemism threatened by hydropower and to prioritize the construction of planned projects.

Proposal of a clinical score to stratify the risk of multidrug-resistant gram-negative rods bacteremia in cancer patients

Introduction

Multidrug-resistant gram-negative rods (MDR GNR) represent a growing threat for patients with cancer. Our objective was to determine the characteristics of and risk factors for MDR GNR bacteremia in patients with cancer and to develop a clinical score to predict MDR GNR bacteremia.

Material and Methods

Multicenter prospective study analyzing initial episodes of MDR GNR bacteremia. Risk factors were evaluated using a multiple logistic regression (forward-stepwise selection) analysis including variables with a p < 0.10 in univariate analysis.

Results

394 episodes of GNR bacteremia were included, with 168 (42.6 %) being MDR GNR. Five variables were identified as independent risk factors: recent antibiotic use (OR = 2.8, 95 % CI 1.7–4.6, p = 0.001), recent intensive care unit admission (OR = 2.9, 95 % CI 1.1–7.8, p = 0.027), hospitalization ≥ 7 days prior to the episode of bacteremia (OR = 3.5, 95 % CI 2–6.2, p = 0.005), severe mucositis (OR = 5.3, 95 % CI 1.8–15.6, p = 0.002), and recent or previous colonization/infection with MDR GNR (OR = 2.3, 95 % CI 1.2–4.3, p = 0.028). Using a cut-off value of two points, the score had a sensitivity of 66.07 % (95 % CI 58.4–73.2 %), a specificity of 77.8 % (95 % CI 71.4–82.7 %), a positive predictive value of 68 % (95 % CI 61.9–73.4 %), and a negative predictive value of 75.9 % (95 % CI 71.6–79.7 %). The overall performance of the score was satisfactory (AUROC 0.78; 95 % CI 0.73-0.82). In the cases with one or none of the risk factors identified, the negative likelihood ratio was 0.18 and the post-test probability of having MDR GNR was 11.68 %.

Conclusions

With the growing incidence of MDR GNR as etiologic agents of bacteremia in cancer patients, the development of this score could be a potential tool for clinicians.

1545. Gram-Negative Bacteremia in Neutropenic Patients: Risk Factors for Mortality in the Era of Multiresistance

Background

Gram-negative bacteremia (GNB) in neutropenic patients is a major cause of infection-related mortality. Our objective was to identify factors associated with 7-day and 30-day mortality during GNB episodes in neutropenic patients.

Methods

Prospective multicenter study. Episodes of GNB in adult neutropenic cancer and hematopoietic stem cell transplant (HSCT) patients were included in 10 centers of Argentina, from May 2014 to January 2018. To identify factors associated with 7-day and 30-day mortality, variables with P < 0.05 in univariate analysis were included in a logistic regression model for multivariate analysis.

Results

Four hundred and seventy-six episodes of GNB were included. From these, 68.06% had hematological malignancies, 22.90% HSCT and 9.03% solid tumors. Seven-day and 30-day mortality were 19.53 and 26.47%, respectively. In multivariate analysis, factors independently associated with 7-day mortality were: Meropenem-resistant GNB (OR 8.60, 95% CI 3.06–24.14, P ≤ 0.0001), respiratory source (OR 3.67, 95% CI 1.21–11.10, P = 0.021), skin and soft tissue source (OR 3.89, 95% CI 1.01–14.94, P = 0.048), Charlson score > 4 (OR 2.76, 95% CI 1.06–7.19, P = 0.037) and shock (OR 7.13, 95% CI 2.50–20.33, P ≤ 0.0001). Independent factors for 30-day mortality were: Meropenem-resistant GNB (OR 7.06, 95% CI 2.83–17.64, P ≤ 0.0001), respiratory source (OR 4.41, 95% CI 1.53–12.73, P = 0.006), skin and soft tissue source (OR 3.66, 95% CI 1.00–13.42, P = 0.049), Charlson score > 4 (OR 3.81, 95% CI 1.62–8.91, P = 0.002), intensive care unit requirement (OR 2.46, 95% CI 1.00–6.04, P = 0.049), shock (OR 10.90, 95% CI 4.12–29.85, P ≤ 0.0001) and refractory cancer (OR 4.30, 95% CI 1.57–11.78, P = 0.005).

Conclusion

The identification of certain prognostic factors would allow the stratification of neutropenic patients at high risk for mortality during GNB episodes. The appropriate medical intervention of a multidisciplinary team on these factors could improve the outcome of these patients. Since Meropenem-resistant GNB is one of strongest prognostic factors, it is essential to identify the patients at risk and treat them appropriately.

Disclosures

All authors: No reported disclosures.

Pandemic 2009 Influenza A (H1N1) virus infection in cancer and hematopoietic stem cell transplant recipients; a multicenter observational study

BACKGROUND

During March 2009 a novel Influenza A virus emerged in Mexico. We describe the clinical picture of the pandemic Influenza A (H1N1) Influenza in cancer patients during the 2009 influenza season.

METHODS

Twelve centers participated in a multicenter retrospective observational study of cancer patients with confirmed infection with the 2009 H1N1 Influenza A virus (influenza-like illness or pneumonia plus positive PCR for the 2009 H1N1 Influenza A virus  in respiratory secretions). Clinical data were obtained by retrospective chart review and analyzed. 

RESULTS

From May to August 2009, data of 65 patients were collected. Median age was 51 years, 57 % of the patients were female. Most patients (47) had onco-hematological cancers and 18 had solid tumors. Cancer treatment mainly consisted of chemotherapy (46), or stem cell transplantation (SCT) (16). Only 19 of 64 patients had received the 2009 seasonal Influenza vaccine. Clinical presentation included pneumonia (43) and upper respiratory tract infection (22). Forty five of 58 ambulatory patients were admitted. Mechanical ventilation was required in 12 patients (18%). Treatment included oseltamivir monotherapy or in combination with amantadine for a median of 7 days. The global 30-day mortality rate was 18%. All 12 deaths were among the non-vaccinated patients. No deaths were observed among the 19 vaccinated patients. Oxygen saturation <96% at presentation was a predictor of mortality (OR 19.5; 95%CI: 2.28 to 165.9).

CONCLUSIONS

In our cancer patient population, the pandemic 2009 Influenza A (H1N1) virus was associated with high incidence of pneumonia (66%), and 30-day mortality (18.5%). Saturation <96% was significantly associated with death. No deaths were observed among vaccinated patients.

Pandemic 2009 Influenza A (H1N1) virus infection in cancer and hematopoietic stem cell transplant recipients; a multicenter observational study

BACKGROUND

During March 2009 a novel Influenza A virus emerged in Mexico. We describe the clinical picture of the pandemic Influenza A (H1N1) Influenza in cancer patients during the 2009 influenza season.

METHODS

Twelve centers participated in a multicenter retrospective observational study of cancer patients with confirmed infection with the 2009 H1N1 Influenza A virus (influenza-like illness or pneumonia plus positive PCR for the 2009 H1N1 Influenza A virus  in respiratory secretions). Clinical data were obtained by retrospective chart review and analyzed. 

RESULTS

From May to August 2009, data of 65 patients were collected. Median age was 51 years, 57 % of the patients were female. Most patients (47) had onco-hematological cancers and 18 had solid tumors. Cancer treatment mainly consisted of chemotherapy (46), or stem cell transplantation (SCT) (16). Only 19 of 64 patients had received the 2009 seasonal Influenza vaccine. Clinical presentation included pneumonia (43) and upper respiratory tract infection (22). Forty five of 58 ambulatory patients were admitted. Mechanical ventilation was required in 12 patients (18%). Treatment included oseltamivir monotherapy or in combination with amantadine for a median of 7 days. The global 30-day mortality rate was 18%. All 12 deaths were among the non-vaccinated patients. No deaths were observed among the 19 vaccinated patients. Oxygen saturation <96% at presentation was a predictor of mortality (OR 19.5; 95%CI: 2.28 to 165.9).

CONCLUSIONS

In our cancer patient population, the pandemic 2009 Influenza A (H1N1) virus was associated with high incidence of pneumonia (66%), and 30-day mortality (18.5%). Saturation <96% was significantly associated with death. No deaths were observed among vaccinated patients.

Étude comparative de deux protocoles d’électrostimulation du quadriceps après chirurgie du ligament croisé antérieur. Étude de faisabilité

OBJECTIVES

To evaluate the feasibility of a study comparing the effects of two protocols of electrical stimulation of the quadriceps femoris after anterior cruciate ligament surgery.

MATERIAL

Seven sportsmen with a mean age of 26 yrs were randomly grouped in two: a 20 Hz stimulated group (4 patients) and a 80 Hz stimulated group (3 patients). After surgery all patients received electrical stimulation of the quadriceps femoris, five days a week, for 12 weeks, and had a standard program of voluntary contractions. The main outcome assessed before and three months after surgery were: quadriceps and hamstring peak torque at 90, 180 and 240 degrees /second, maximal isometric quadriceps at 75 degrees of flexion and muscle and subcutaneous fat volumes of the thigh using MRI.

RESULTS

After 12 weeks of rehabilitation, the thigh muscle volume deficit of the operated limb was between 3 and 9% in the 20 Hz stimulated group and between 1 and 2% in the 80 Hz stimulated group. Quadriceps peak torque deficit was less than 30% except for two patients in the 20 Hz stimulated group. Maximal isometric quadriceps deficit of the operated limb was higher than 30% except for two patients in the 20 Hz stimulated group.

CONCLUSION

The study showed that comparison of two protocols of electrical stimulation of the quadriceps femoris after anterior cruciate ligament surgery is possible if stimulation period is not more than four weeks.

10CASA EVALUATION OF SEXED AND NON-SEXED FROZEN BULL SEMEN

Flow citometry cell sorting has been proven successfully to separate X and Y sperm; however, the technology is still too stressfull for the viability of the sorted semen. The objective of this study was to evaluate nonsexed and sexed frozen sperm motility characteristics using a CASA technology. Ejaculates from 4 different bulls (3 Holstein and 1 Angus) were collected, and processed as split non-sexed and sexed semen samples using Tris egg yolk extenders. X and Y sperm were separated using a high-speed sorter (SX Moflo). Cryopreservation was done at the same time under appropiate conditions using a programmed cryochamber. Thawing procedure was done at 37°C for 30s and a sample of each straw was placed in the evaluation chamber. The experiment was repeated twice and two chambers with 30 observations each were analyzed each time. Mean and standard deviation of each characteristic were calculated, compared and analyzed statistically. The sperm concentration was determined by means of a burker counting chamber. Sperm quality was determined at 0h after thawing, and later at 1h, 2h and 3h after incubation in a glass tube at 30°C. The following sperm motility parameters were determined with the Hamilton Thorne (HTM-ceros 12.1) on at least 1000 spermatozoa: velocity average path (VAP), velocity straight line (VSL), amplitude lateral head (ALH), beat cross frequency (BCF), straightness (STR), linearity (LIN), and percentage of progressively motile spermatozoa (PMS). Linearity of nonsexed spermatozoa was 53±3.5, 47±0.8, 43±7.8 and 42±4.5 for the 0h and the 3 test incubation times and 49.5±3.7, 51.2±3.7, 43.3±7.8 and 44.5±7.6, respectively, for sexed semen. There were no significant differences (P&gt;0.05) in the progressive velocity, track speed and linearity between sexed and nonsexed semen. The percentage of static cells was 33%, 30%, 47% and 50% for the 0h and the 3 test incubation periods; however, the percentage of static cells for the sexed semen was 53%, 71%, 77% and 82%, respectively. Results from the analysis indicate a significant increase (P&lt;0.01) in the number and the percentage of static cells with time. The lateral amplitude of sperm motility for nonsexed semen was 5.9±0.5, 6.8±0.8, 6.0±0.4 and 5.1±0.7, and for sexed semen 6.6±0.7, 6.8±0.4, 6.4±0.4 and 5.5±1.7, respectively. The percentage of progressively motile sperm was significantly different at 0 time 49.7±4.9 and 23.1±4.9 for nonsexed and sexed semen respectively. After 3 hours of incubation the percentage of progressively motile sperm was 38.7±10.2 and 3.7±3.2 for nonsexed and sexed semen, respectively. In conclusion, sexed frozen semen seems to have characteristics similar to those of normal nonsexed semen. However, a significant decrease in the percentage of progressively motile cells could affect pregnancy rates. More research needs to be done to detect differences between bulls and cryoprotectans.Research supported by Centro Genetico Bovino de EOLIA sa Argentina.

Effects of two electrical stimulation frequencies in thigh muscle after knee surgery

The purpose of this study was to compare the effects of two protocols of electrical stimulation combined with voluntary contractions on the recovery of thigh muscles after anterior cruciate ligament (ACL) surgery. Ten sportsmen with a mean age of 26 yrs were randomly assigned into two groups: a 80 Hz stimulated group (5 patients) and a 20 Hz stimulated group (5 patients). All patients received electrical stimulation of the quadriceps femoris, five days a week, for 12 weeks, and had a standard program of voluntary contractions. Muscle and fat volumes of the thigh were assessed using MRI before surgery and after 12 weeks of rehabilitation. Quadriceps and hamstring muscle strength were evaluated by isokinetic measurements. Twelve weeks after surgery, the quadriceps peak torque deficit in the operated limb with respect to the non operated limb at 180 degrees /s and 240 degrees /s was significantly (p < 0.05) less in the 20 Hz group than in the 80 Hz group. This difference was not confirmed when comparing the pre-surgery quadriceps peak torque of the operated limb with the post-surgery one. Subcutaneous fat volume was increased for the two groups at the post-surgery test. This increase was significantly (p < 0.05) greater for the 80 Hz group. Thigh muscle volume deficit was not significantly different between the two groups.

Leber's hereditary optic neuropathy: heteroplasmy is likely to be significant in the expression of LHON in families with the 3460 ND1 mutation

AIM

To assess the effect of heteroplasmy on the expression of Leber's hereditary optic neuropathy (LHON) in a large family with the 3460 LHON mutation.

METHODS

Mutation detection was performed by restriction enzyme digestion of polymerase chain reaction (PCR) products. Heteroplasmy was estimated by quantitation of wild type:mutant product ratios.

RESULTS

There is a significant association between levels of mutant mtDNA and manifestation of the disease phenotype.

CONCLUSION

As a high proportion of families with the 3460 mutation demonstrate heteroplasmy; this is likely to be a significant factor in disease expression.

Leber's hereditary optic neuropathy: implications of the sex ratio for linkage studies in families with the 3460 ND1 mutation

Leber's hereditary optic neuropathy (LHON), which is associated with mutations in mitochondrial DNA (mtDNA), is commoner in males than females. A study of over 30 LHON families with a mutation at position 3460 of mtDNA demonstrates a significantly decreased male excess from that generally quoted, with evidence for a marked bias in the ascertainment of males over females. This has implications for the analysis of those factors which give rise to the male bias.

Plants that poison in Uruguay

Poisoning by plants has different traits in each country, according to geographical, botanical and also socio-cultural characteristics. The incidence of "plant calls" to the Poison Control Center in Uruguay is not very high, but it is due usually to symptomatic cases affecting children. Plant poisoning in adults is less frequent, being due to home-made medicine, and, in women, to the popular belief in the abortive quality of some plants. Suicide attempts are rare. The different species that cause consultations, and the clinical characteristics are briefly analyzed, as well as the problems that a Poison Control Center usually has to face in poisoning by plants.