Research

Differences and similarities in binding of pyruvate and l-lactate in the active site of M4 and H4 isoforms of human lactate dehydrogenase

2011-05-09T14:05:00.001-07:00

Abstract
We present QM/MM calculations that show differences in geometries of active sites of M4 and H4 isoforms of human LDH ligated with oxamate, pyruvate or l-lactate. As the consequence of these differences, binding isotope effects of the methyl hydrogen atoms of pyruvate and l-lactate may be used to experimentally distinguish these isoforms. Based on the FEP calculations we argue that l-lactate is a better candidate for the experimental studies. Our calculations of energies of interactions of ligands with the active site residues provide explanation for the observed experimentally sensitivity to inhibition of the M4 isoenzyme isoform and pinpoint the differences to interactions of the ligand with the histidine residue. We conclude that pyruvate interacts much stronger in the active site of H4 than M4 isoform and that the latter interactions are weaker than with water molecules in the aqueous solution

Research highlights
► Isoforms M4 and H4 of human lactate dehydrogenase exhibit different BIEs of pyruvate and l-lactate. ► Hydrogen BIEs of l-lactate and pyruvate can be used for differentiation of the LDH isoforms. ► Affinities of pyruvate toward active sites of M4 and H4 are different. ► l-lactate is a good candidate for experimental differentiation of LDH isoforms.

Conclusions
Studies presented herein explain the experimental observations where H4 isoform is much more sensitive to inhibition than the M4 isoenzyme. The studies of energies of interactions of ligands with the active site residues provide explanation to this problem and pinpoint the differences to interactions of pyruvate with the histidine residue. Our theoretical studies show that pyruvate interacts much stronger in the active site of H4 than M4 isoform. Moreover, the interactions of pyruvate with active site of M4 isoform are weaker that with water molecules in the aqueous solution.

Using QM/MM calculations it was shown that the geometries of the LDH active sites are significantly different when oxamate, pyruvate or l-lactate are ligated. Because of these differences M4 and H4 isoforms of human LDH may be distinguished on the basis of binding isotope effects of hydrogen atoms of the methyl group of pyruvate and l-lactate. FEP calculations indicate that pyruvate has low affinity to the active site of the M4 isoform thus it seems safer to use l-lactate as a ligand for experimental differentiation the LDH isoforms.

Archives of Biochemistry and Biophysics
Volume 505, Issue 1, 1 January 2011, Pages 33-41
Special Section: Trends in Enzymology 2010

Increased myeloperoxidase enzyme activity in plasma is an indicator of inflammation and onset of sepsis

2011-02-22T13:43:00.000-08:00

Circulating lipopolysaccharides released from bacteria may activate both neutrophils and monocytes. The activated neutrophils release myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to evaluate MPO enzyme activity in plasma of critically ill patients and to check the hypothesis that these concentrations in plasma would be higher in sepsis and systemic inflammatory conditions, as neutrophils release their contents before proliferating in response to stress.

Results
The plasma MPO enzyme activity in sepsis patients was significantly higher than that in the control group (mean, 2.4 ± 1.8 in sepsis and 1.86 ± 1.2 nmol per milligram protein per 10 minutes in systemic inflammatory response syndrome vs 0.32 ± 0.11 nmol per milligram protein per 10 minutes in healthy controls). Mean plasma lactate levels in sepsis (7.8 ± 1.2 mmol/L) and shock patients (9.5 ± 1.2 mmol/L) and cytokines like tumor necrosis factor–α, interleukin-8, and interleukin-1β were simultaneously evaluated to establish onset of inflammation and sepsis. These results show that neutrophil activation occurring during inflammation and sepsis could be detected by plasma MPO concentration

Conclusion : The plasma MPO concentrations may be a marker of the neutrophil proliferation and severity of inflammation

a Department of Anaesthesia, Chatrapati Shahuji Maharaj Medical University, Lucknow, UP, India

b Pharmacology Division, Central Drug Research Institute, Lucknow, UP, India

"Contagious Yawning in Autistic and Typical Development"

2010-09-15T13:14:00.000-07:00

Molly S. Helt, Inge-Marie Eigsti, Peter J. Snyder, Deborah A. Fein
Child Development Article first published online: 14 SEP 2010

If somebody yawns it is likely that half the people nearby will probably do the same - a occurrence we call contagious yawning. However, children with severe autism miss the subtle cues that elicit collective yawning, say researchers from the University of Connecticut in a study published in the medical journal Child Development. The writers say their findings may help experts determine why people with autism find it harder to form close emotional bonds with others.

The investigators also found that individuals with milder variants of ASD (autism spectrum disorder) were more likely to yawn contagiously that those with more severe autism. They also found that most children with or without autism under the age of four years are much less likely to be contagiously yawning.

Molly Helt, a doctoral student in the Department of Psychology, College of Liberal Arts and Sciences, University of Connecticut, and the study's primary author, wrote:

This lends support to the idea that the social mind develops over time through a process of mimicry and feedback. If we can identify a lack of mimicry of facial expressions early, it could be an identifier of potential neurodevelopment disorders such as autism.

Contagious yawning is a form of mimicry, something apparently unique to humans and chimpanzees - researchers believe we acquire it over time. It is different from spontaneous yawning, which all vertebrates do. Spontaneous yawning has been observed in fetuses in the womb.

Helt's study differs from previous ones in that it included live stimulis - human experimenters - as opposed to just exposing participants to videos of people yawning. The study compared children with severe autism, children diagnosed with a Pervasive Development Disorder, and kids with neither (typically developing children).

The study was divided into two parts:

The first study - including only typically developing children

120 typically developing children aged between 1 and 6 years were recruited from local daycare centers. They sat in a quiet room facing the experimenter who sat on the other side of the room. The experimenter read a story out loud, one of four stories which depended on the age of the children, for a total of 12 minutes. During the last 10 minutes of the reading the experimenter yawned four times, and recorded (discreetly) whether any child yawned within 90 seconds. About 40% of the reading sessions were randomly recorded on video and coded by two independent raters for reliability.

If a child yawned in response to one or more of the experimenter's stimulus yawns, he/she was considered a contagious yawner. The experimenter did not include in the analysis children who were not looking the experimenter most of the time.

The authors report that children under four years of age were much less likely to engage in contagious yawning, compared to the older kids.
There were 20 children aged just 1 year - none of them yawned.
There were 20 children aged 2 years - 1 of them yawned.
There were 20 children aged 3 years - 2 of them yawned. There were 20 children aged 4 years - 7 of them yawned.
There were 20 children aged 5/6 years - 8 of them yawned

We saw a major jump to adult levels of contagious yawning at age four. We thought that was the most surprising thing. We thought it would be quite a bit younger.

The second study - both children with autism and typically developing children This study involved 15 children with ASDs (autism spectrum disorders) and two control groups with typically developing children of the same age - a total of 28 children.

The test was identical to what was tried out in the first study.

The researchers found that:
Those with autism spectrum disorders yawned about half as often as the typically developing children did.
None of the children with severe autism got caught up in contagious yawning.
Helt believes that children with autism have a deficit in early social learning that impedes and undermines their ability to mimic the actions and emotions of others around them.

Helt added:

This lack of early mimicry could also impact feelings of psychological connection and opportunities for social learning. These changes could thus leave children with autism unable to recognize primitive socio-emotional clues that could otherwise serve to biologically and emotionally synchronize them with people around them.

The authors believe their findings may help people who work with children with ASDs develop approaches that focus more on social and emotional cues.
What is autism?
Autism is known as a complex developmental disability. Clinicians believe that Autism presents itself during the first three years of a child's life. The condition is the result of a neurological disorder that has an effect on normal brain function, affecting development of the person's communication and social interaction skills.

People with autism have problems with non-verbal communication, a wide range of social interactions, and activities that include an element of play and/or banter.

ASD stands for Autism Spectrum Disorder and can sometimes be referred to as Autistic Spectrum Disorder. ASDs are any developmental disabilities that have been caused by a brain abnormality. A person with an ASD typically has difficulty with social and communication skills.

A person with ASD will typically also prefer to stick to a set of behaviors and will resist any major (and many minor) changes to daily activities. Several relatives and friends of people with ASDs have commented that if the person knows a change is coming in advance, and has time to prepare for it; the resistance to the change is either gone completely or is much lower.

Click here to read about autism in more detail.

Source: University of Connecticut, Medical News Today (archives)

"Contagious Yawning in Autistic and Typical Development"
Molly S. Helt, Inge-Marie Eigsti, Peter J. Snyder, Deborah A. Fein
Child Development Article first published online: 14 SEP 2010
DOI: 10.1111/j.1467-8624.2010.01495.x

High salivary alpha-amylase levels in patients with schizophrenia: A pilot study

2010-05-17T12:18:00.000-07:00

Abstract
Previous studies have demonstrated the autonomic dysregulation in patients with schizophrenia using electrophysiological methods, such as electrodermal measures and heart rate analysis.

Several theories have been proposed to explain the underlying mechanisms of schizophrenia and its autonomic function. Recently, the measurement of salivary alpha-amylase has been considered to be a useful tool for evaluating the sympathetic-adrenal-medullary (SAM) system. Psychosocial stress increases the release of salivary alpha-amylase.

Although some studies have evaluated salivary alpha-amylase under psychosocial stress, no studies have demonstrated the change in the salivary alpha-amylase (sAA) activity level in schizophrenic patients. We examined the relationship between sAA level and psychiatric state in patients with schizophrenia (n = 54) using a portable and rapid hand-held monitor to investigate sAA. The sAA activity in the patients was significantly higher than that in the control subjects (n = 55) (p < 0.01). The correlation between amylase level and psychiatric symptoms was highly significant (r = 0.37, p < 0.01).

These findings indicate that higher increases in sAA may indicate severe psychiatric symptoms. These results indicate a predominant role of the sympathetic nervous system in the secretion of sAA, together with parasympathetic withdrawal, under psychosocial stress.

Takuji Inagakia, , , Tsuyoshi Miyaokab, Shihoh Okazakib, Hideaki Yasudab, Tetsuya Kawamukaib, Etsuko Utanib, Rei Wakeb, Maiko Hayashidab, Jun Horiguchib and Seiichi Tsujic

a Department of Psychology and Special Support Education, Faculty of Education, Shimane University, Matsue, Japan

b Department of Psychiatry, Faculty of Medicine, Shimane University, Izumo, Japan

c Tsuji Clinic, Hiroshima, Japan

Relevance of declines in serum human chorionic gonadotropin levels to the management of persistent ectopic pregnancy

2009-12-07T11:22:00.000-08:00

ABSTRACT
Aim: To evaluate postoperative declines in serum human chorionic gonadotropin (hCG) levels (percentages of preoperative hCG levels) to rule out persistent ectopic pregnancy (PEP).

Methods: A retrospective study was conducted on 50 patients who underwent laparoscopic salpingotomy between April 1995 and March 2008. The postoperative course was divided into four periods: (period A: days 1–2; period B: days 3–4; period C: days 5–6; and period D: days 7–8), and the postoperative serum human chorionic gonadotropin declines in the PEP and control groups (successfully treated patients) were compared. A cutoff value of serum hcg decline to rule out PEP was established by receiver operating characteristic (ROC) analysis.

Results: Ten of the 50 patients (20%) were diagnosed with PEP. There were no differences in clinical findings or preoperative serum hCG levels between the two groups. From period C, the serum hCG decline in the control group was significantly greater than in the PEP group, and all individual serum hCG declines in the PEP group were outside the 95% confidence interval of the control group. Furthermore, analysis by ROC using a 14% decline in postoperative serum hCG as a cutoff revealed that the specificity and sensitivity of the test were equal to 100% from period C.

Conclusion: Declines in serum hcg during period C (days 5–6) constitute an important marker of the presence or absence of PEP. Decisions regarding a second intervention for PEP should be made by this time postoperatively.

Journal of Obstetrics and Gynaecology Research
Volume 35 Issue 5, Pages 961 - 966
Published Online: 23 Oct 2009

Relevance of declines in serum human chorionic gonadotropin levels to the management of persistent ectopic pregnancy
Takashi Abe, Shigeo Akira, Yasuyuki Negishi, Masao Ichikawa, Akihito Nakai and Toshiyuki Takeshita

Efficacy and safety of sorafenib in patients

2009-11-24T11:24:00.000-08:00

Efficacy and safety of sorafenib in patients with advanced hepatocellular carcinoma (HCC): Asia-Pacific (AP) trial subgroup analyses by baseline transaminase (ALT/AST)/-alpha fetoprotein (AFP) levels

Journal of Clinical Oncology, 2009 ASCO Annual Meeting Proceedings (Post-Meeting Edition).Vol 27, No 15S (May 20 Supplement), 2009: 4590

Background: Results of the phase III, randomized, double blind, placebo-controlled AP trial demonstrated that sorafenib is effective and safe for the treatment of advanced HCC in patients from the AP region (Cheng et al, Lancet Oncol, 2009). Hepatic function influences treatment as a measure of organ damage and tumor stage. We performed subset analyses of the AP study dataset according to baseline hepatic function, as indicated by levels of ALT/AST and AFP.

Methods: Patients (N=226) with advanced HCC, ECOG PS 0–2, Child-Pugh class A, and no prior systemic therapy were randomized 2:1 to receive sorafenib 400 mg BID or placebo. Endpoints included overall survival (OS), disease-control rate (DCR; defined as complete/partial response or stable disease by RECIST, maintained for 28 days from first demonstration of response), time to progression (TTP) and safety. Patients were grouped by baseline levels of ALT/AST (normal, mild, or moderate) and AFP (normal or abnormal).

Results: Median TTP, OS and DCR by subset are shown in the table. The most common grade 3/4 adverse events in the sorafenib populations were hand-foot skin reaction and diarrhea.

Conclusions: Sorafenib was effective and safe in patients from the AP region with advanced HCC within a broad range of baseline hepatic enzyme and AFP levels. These results suggest that sorafenib is an effective treatment for HCC, irrespective of baseline ALT/AST or AFP levels

Predictive value of mid-trimester amniotic fluid high-sensitive C-reactive protein, ferritin, and lactate dehydrogenase for fetal growth restriction

2009-11-04T15:02:00.000-08:00

Predictive value of mid-trimester amniotic fluid high-sensitive C-reactive protein, ferritin, and lactate dehydrogenase for fetal growth restriction.
Borna S, Abdollahi A, Mirzaei F.

Department of Gynecology and Obstetrics, Tehran University/ Medical of Science, Iran.

BACKGROUND: Fetal growth restriction (FGR) is surprisingly common with placental dysfunction occurring in about 3% of pregnancies and despite advances in obstetric care, FGR remains a major problem in developed countries. AIM: The purpose of this study is to find out the predictive value of amniotic fluid high sensitive C-reactive protein (hs-CRP), ferritin , and lactate dehydrogenase (LDH) for FGR.

MATERIALS AND METHODS: This prospective strategy of this study has been conducted on pregnant women who underwent genetic amniocentesis between 15th and 20th weeks of gestation. All patients were followed up on until delivery. Patients with abnormal karyotype and iatrogenic preterm delivery for fetal and maternal indications were excluded. The samples were immediately sent to laboratory for cytogenetic and biochemical examination. Non-parametric tests and receiver-operator characteristic curve analysis were used for statistical purpose.

RESULTS: A significant correlation between incremental amniotic fluid alpha fetoprotein (alphaFPr) and LDH levels and FGR at gestational weeks 15th-20th was found out. We also found an optimum cut-off value> 140 IU/L for the amniotic fluid LDH concentration with a sensitivity of 87.5% and a specificity of 82.4% for the prediction of FGR.

CONCLUSION: Once the LDH value is confirmed, it could serve as a prediction factor for FGR at the time of genetic amniocentesis at gestational weeks 15-20.

Recombinant human albumin as protein source in culture media used for IVF

2009-09-08T08:28:00.000-07:00

Oocytes obtained from 85 women undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment were randomly selected for culture in media containing either human serum albumin (HSA), (n = 42) or recombinant human albumin (rHA), (n = 43). At the time of transfer, the two embryos with the overall best morphology were selected on day 2, 3 or 5. Comparable rates of fertilization, cleavage, blastocyst formation and implantation were observed in both groups. The frequency of pregnancy and early pregnancy loss were also equal. It is concluded that culture media containing rHA seem to produce embryos of high quality comparable to media containing HSA. Therefore, rHA may replace HSA as a protein source in culture media for IVF and may reduce risks of prion contamination and transmission of plasma derived impurities.

Bungum M, Humaidan P, Bungum L.
Fertility Clinic, Skive Sygehus, Resenvej 25, Denmark

Prevalence of metabolic syndrome increases with the increase in blood levels of gamma glutamyltransferase and alanine aminotransferase in Japanese men

2009-08-24T14:19:00.000-07:00

BACKGROUND: Gamma glutamyltransferase ( GGT ) or alanine aminotransferase ( ALT) is reported to be an independent risk factor of diabetes and cardiovascular disease and proposed as a component of metabolic syndrome (MS). However, there are few studies examining the direct association between MS and Gamma glutamyltransferase or alanine aminotransferase in Japanese men and women.

METHODS: Direct associations between GGT or ALT and MS defined by revised NCEP criteria for Japanese and between GGT or ALT and Japanese MS (JMS) defined by the Examination Committee for the Criteria of Metabolic Syndrome were examined using medical check-up data from 1,880 men and 1,079 women.

RESULTS: The prevalence of MS and JMS was significantly higher in subjects with the highest quartile of GGT or ALT than the subjects with the lowest quartile of GGT or ALT (p<0.0001 in men and p<0.0001 for MS and p<0.001 for JMS in women). The optimal cutoff points of GGT and ALT for diagnosing MS or JMS were 42 U/L or 41 U/L, respectively for GGT and both 25 U/L for ALT in men and 21 U/L or 23 U/L, respectively for GGT and 20 U/L or 25 U/L, respectively for ALT in women.

CONCLUSION: The prevalence of MS and JMS increases with the increase in blood levels of GGT or ALT even through the normal range of GGT or ALT in Japanese men and women.

Tachikawa Medical Center, Nagaoka

Analysis of urobilinogen and urine bilirubin for intra-abdominal injury in blunt trauma patients

2009-07-07T19:26:00.000-07:00

OBJECTIVE: To determine the point prevalence of urine bilirubin, urine hemoglobin and urobilinogen in blunt trauma patients, and to evaluate its utility as a screening tool for intra-abdominal injury.

METHODS: Data analysis of 986 consecutive trauma patients of which 698 were adult blunt trauma patients. Five-hundred sixteen subjects had a urinalysis and a CT scan of the abdomen/pelvis or exploratory laparotomy. We reviewed initial urinalysis results from trauma patients in the emergency department (ED) for the presence of urine hemoglobin, uroblinogen and urine bilirubin . Computed tomography (CT) scan results and operative reports were reviewed from the trauma registry for evidence of liver laceration, spleen laceration, bowel or mesenteric injuries.

RESULTS: There were 73 injuries and 57/516 patients (11%) with intra-abdominal injury. Urinalysis was positive for urobilinogen in 28/516 (5.4%) patients, urine bilirubin in 15/516 (2.9%) patients and urine hemoglobin in 313/516 (61%) patients. Nineteen/forty-seven (4%) subjects had liver lacerations, 28/56 (5%) splenic lacerations, and 15/5 (3%) bowel or mesenteric injury.

Comparing the proportion of patients that had urobilinogen detected in the group with and without intra-abdominal injury, 8/28 (29%) subjects with urobilinogen, 5/15 (33%) subjects with bilirubin and 47/313 (15%) subjects with urine hemoglobin were found to have liver lacerations, spleen lacerations, or bowel/mesenteric injuries. Preexisting liver or biliary conditions were not statistically associated with elevation of urine bilirubin, urine hemoglobin or on initial urobilinogen urinalysis after blunt abdominal trauma. Point prevalence for urobilinogen, urine bilirubin and urine hemoglobin are 5.43% (28/516), 2.91% (15/516) and 60.7% (313/516) respectively.

CONCLUSIONS: The utility of the initial routine urinalysis in the ED for adult blunt abdominal trauma patients should not be used as a screening tool for the evaluation of intra-abdominal injury.

Chronic kidney disease (CKD) is more likely to progress to end-stage renal disease in African Americans

2009-06-22T08:49:00.000-07:00

Chronic kidney disease (CKD) is more likely to progress to end-stage renal disease (ESRD) in African Americans while the reasons for this are unclear. The metabolic syndrome is a risk factor for the development of diabetes, cardiovascular disease, and has been recently linked to incident CKD. Historically, fewer African Americans meet criteria for the definition of metabolic syndrome, despite having higher rates of cardiovascular mortality than Caucasians. The presence of microalbuminuria portends increased cardiovascular risks and has been shown to cluster with the metabolic syndrome. We recently reported that proteinuria is a predictor of CKD progression in African American hypertensives with metabolic syndrome. In this review we explore the potential value of including CKD markers--microalbuminuria/proteinuria or low glomerular filtration rate (GFR)-in refining the cluster of factors defined as metabolic syndrome, ie, "cardiorenal metabolic syndrome."

Lea JP, Greene EL, Nicholas SB, Agodoa L, Norris KC.
Department of Medicine, Renal Division, Emory University, 550 Peachtree St., 8th floor, Atlanta, Georgia 30308

Improved outcome for Chinese children with acute promyelocytic leukemia

2009-05-13T19:05:00.000-07:00

OBJECTIVE: Acute promyelocytic leukemia (APL) is now highly curable, except in many developing countries. Introduction of current treatment strategies may improve the outcome for children with APL in these countries. METHODS: The diagnosis was based on the FAB classification and detection of PML-RARalpha rearrangement. From December 1999 to September 2004, 16 eligible children were treated with an intensive in-house protocol including high-dose AraC and anthracycline. Subsequently, 14 cases were treated with a less intensive protocol modified from the PETHEMA LPA99. RESULTS: The 3.5 years event-free survival (EFS) was 37.5% (95% CI, 13.8-61.2%) for patients treated on initial protocol. The treatment failures were: six patients abandoned treatment (37.5%), two who died of intracranial hemorrhage at diagnosis (6.3%) and sepsis in remission (6.3%) respectively, and two who relapsed (12.5%). Those treated on modified PETHEMA had a 3.5 years EFS of 79.6% (95% CI, 52.9-106.3%). Treatment failures included: one who died of intracranial hemorrhage at diagnosis (7.1%) and one who relapsed (7.1%). The patients on modified PETHEMA had a significantly higher EFS (P = 0.012), lower frequency of sepsis during treatment (7.7% vs. 77.8%; P = 0.0015), and lower hospitalization cost (median US$ 4,700 vs. US$ 20,000; P < 0.0001) than those on in-house protocol. CONCLUSION: Treatment with the less intensive protocol based on the PETHEMA LPA99 study of childhood APL successfully reduced chemotherapy toxicity and lowered hospitalization costs without increasing relapses. This led to decreases in treatment-related morbidity and the treatment abandonment rate, thus improving overall outcome. Pediatr Blood Cancer

Department of Pediatric, The First Affiliated Hospital of Sun Yat-Sen University, Zhongshan Er Lu, Guangzhou, China.