Prostanoid receptors: subtypes and signaling

Cyclooxygenases metabolize arachidonate to five primary prostanoids: PGE(2), PGF(2 alpha), PGI(2), TxA(2), and PGD(2). These autacrine lipid mediators interact with specific members of a family of distinct G-protein-coupled prostanoid receptors, designated EP, FP, IP, TP, and DP, respectively. Each of these receptors has been cloned, expressed, and characterized. This family of eight prostanoid receptor complementary DNAs encodes seven transmembrane proteins which are typical of G-protein-coupled receptors and these receptors are distinguished by their ligand-binding profiles and the signal transduction pathways activated on ligand binding. Ligand-binding selectivity of these receptors is determined by both the transmembrane sequences and amino acid residues in the putative extracellular-loop regions. The selectivity of interaction between the receptors and G proteins appears to be mediated at least in part by the C-terminal tail region. Each of the EP(1), EP(3), FP, and TP receptors has alternative splice variants described that alter the coding sequence in the C-terminal intracellular tail region. The C-terminal variants modulate signal transduction, phosphorylation, and desensitization of these receptors, as well as altering agonist-independent constitutive activity.

Effect of maximizing oxygen delivery on morbidity and mortality rates in critically ill patients: a prospective, randomized, controlled study

OBJECTIVE

To determine the effects of optimizing oxygen delivery (DO2) to "supranormal" levels on morbidity and mortality in patients with sepsis, septic shock, and adult respiratory distress syndrome.

DESIGN

A prospective, randomized, controlled trial.

SETTING

A 16-bed surgical intensive care unit (ICU) and 14-bed mixed medical/surgical ICU in two separate hospitals in the University of Hawaii Surgical and Internal Medicine Residency programs.

PATIENTS

During a 1-yr period, 67 patients who had pulmonary artery catheters and who met the criteria for sepsis or septic shock, adult respiratory distress syndrome, or hypovolemic shock were enrolled in the study. Patients admitted to the ICU who were < 18 yrs old, or with a do-not-resuscitate order, or those patients who faced imminent death (< 24 hrs), such as those patients with uncontrollable hemorrhage or brain death, were excluded from the study.

INTERVENTIONS

Patients were randomized into treatment and control groups. The treatment group was assigned a therapeutic DO2 indexed (DO2I) goal of > 600 mL/min/m2. Interventions to attain this goal included fluid boluses, administration of blood products, and the use of inotropes. The control group was not assigned to a specific therapeutic goal other than "normal" values of DO2I of 450 to 550 mL/min/m2. Every attempt was made to reach the therapeutic goals within the first 24 hrs after entry into the study. Hemodynamic measurements were obtained on study patients every 4 hrs until the end of the study. The severity of illness was evaluated using the Therapeutic Intervention Scoring System, and the Acute Physiology and Chronic Health Evaluation II scoring system.

MEASUREMENTS AND MAIN RESULTS

There were 32 patients in the control group and 35 patients in the treatment group. The groups were similar in age, sex, number of organ dysfunctions, Acute Physiology and Chronic Health Evaluation II and Therapeutic Intervention scores. There were no statistical differences between the two groups in mortality, development of organ failure, ICU days, and hospital days. Upon analysis, it became apparent that the patients comprised clinically distinct subgroups, including: a) a treatment group who achieved supranormal DO2I; b) a control group with normal DO2I; c) a treatment group who failed to reach target DO2I; d) a control group who self-generated to high DO2I values; and e) a small number of patients who could not even reach a normal DO2I of 450 mL/min/m2. These subgroups were found to be similar and matched. The mortality rate was significantly lower for patients in groups who reached supranormal values of DO2I whether treated or self-generated as compared with patients who reached normal DO2I values (14% vs. 56%, p = .01).

CONCLUSIONS

Although there was no statistically significant difference in the control vs. treatment groups, subgroup analysis demonstrated a strong, significant difference between patients with supranormal values of oxygen transport vs. patients with normal levels of DO2. Supranormal values of DO2I, whether self-generated or as a result of treatment, resulted in a statistically significant decrease in mortality rate. This study adds to the weight of evidence that current standard of care of treating critically ill patients to normal DO2I should be reconsidered, and that maximizing to high DO2I might be a more appropriate therapeutic end-point.

Calciphylaxis in patients on hemodialysis: a prevalence study

BACKGROUND

Calciphylaxis is characterized by painful, violaceous, mottled skin lesions (livedo reticularis) that may progress to tissue necrosis, nonhealing ulcers, gangrene, and potentially amputation, sepsis, or death. The prevalence and characteristics of patients who have calciphylaxis need further identification to predict which patients on dialysis may benefit from close monitoring or early surgical intervention.

METHODS

All 242 patients undergoing hemodialysis in an outpatient unit were reviewed retrospectively during a 15-month cross-sectional study of the prevalence and characteristics of calciphylaxis.

RESULTS

Ten patients (prevalence, 4.1%) had calciphylaxis. Patients with calciphylaxis were significantly younger (49 versus 60 years; p = 0.01), had undergone hemodialysis longer (80 versus 20 months; p < 0.0001), and had higher median serum calcium (9.7 versus 9.2 mg/dl; p = 0.03), phosphate (8.2 versus 5.7 mg/dl; p = 0.001), calcium phosphate product (81.5 versus 52.9; p = 0.0004), parathyroid hormone (1496 versus 138 pg/ml; p < 0.0001), and alkaline phosphatase levels (188 versus 89 IU/L; p = 0.0001). Bone surveys were positive in all 10 patients with calciphylaxis compared with 49 (21%) of the 232 patients without calciphylaxis (p < 0.0001). All patients who underwent parathyroidectomy for calciphylaxis had dramatic healing of the ulcers.

CONCLUSIONS

The presence of calciphylaxis is higher among younger patients who had undergone longer periods of hemodialysis. Therefore this group of patients should be monitored aggressively and treated expeditiously for complications of secondary hyperparathyroidism.

A successful program to lower cesarean-section rates

Despite the consensus that national cesarean-section rates are excessive, they continue to rise. Currently, approximately one of every four deliveries is by cesarean section. We developed an initiative to reduce the number of cesarean deliveries to a rate of 11 percent of all deliveries at our inner-city hospital. Participation by attending physicians was voluntary and not linked to any sanction. The program included a stringent requirement for a second opinion, objective criteria for the four most common indications for cesarean section, and a detailed review of all cesarean sections and of individual physicians' rates of performing them. During the first two years of the program, the cesarean-section rate fell from 17.5 percent of 1697 deliveries in 1985 to 11.5 percent of 2301 deliveries in 1987 (P less than 0.05). The proportion of infants with five-minute Apgar scores lower than 7 increased from 3 percent in 1985 to 4.9 percent in 1987 (P less than 0.05), but neither the fetal mortality rate (11.9 per 1000) nor the neonatal mortality rate (11.2 per 1000) in 1987 differed significantly from the rates in 1985. A single maternal death, unrelated to cesarean delivery, occurred during the study. Rates of both primary and repeat cesarean sections decreased, although only the decline in the rate of primary cesarean sections, from 12 to 6.8 percent, was statistically significant (P less than 0.05). During the same period, operative vaginal deliveries (i.e., forceps deliveries and midpelvic procedures) declined from 10.4 to 4.3 percent (P less than 0.05) of total deliveries. We conclude that an initiative within an obstetrics department can reduce cesarean-section rates substantially without adverse effects on the outcome for mother or infant.

Tissue-specific expression patterns and fine mapping of the human kallikrein (KLK) locus on proximal 19q13.4

The tissue or glandular kallikreins (KLK) are members of a highly conserved multigene family encoding serine proteases that are central to many biological processes. The rodent KLK families are large, highly conserved and clustered at one locus. The human KLK gene family is clustered on chromosome 19q13.3-13.4, and until recently consisted of just three members. However, recent studies have identified up to 11 new members of the KLK family that are less conserved than their rodent counterparts. Using a Southern blot and sequence analysis of 10 BACs and cosmids spanning approximately 400 kilobases (kb) either side of the original KLK 60-kb locus, we demonstrated that these genes also lie adjacent to this. We have also clarified the position of several microsatellite markers in relation to the extended KLK locus. Moreover, from Southern blot analysis of the cosmids and BACs with a degenerate oligonucleotide probe to the histidine-encoding region of serine proteases, we have shown that there are no other serine protease genes approximately 400 kb centromeric and 220 kb telomeric of the extended locus. We performed an extensive analysis of the expression patterns of these genes by poly(A)(+) RNA dot blot and reverse transcriptase-polymerase chain reaction analysis, and demonstrated a diverse pattern of expression. Of interest are clusters of genes with high prostate (KLK2-4) and pancreatic (KLK6-13) expression suggesting evolutionary conservation of elements conferring tissue specificity. From these findings, it is likely that the human KLK gene family consists of just 14 clustered genes within 300 kb and thus is of a comparable size to the rodent families (13-24 genes within 310 and 480 kb, respectively). In contrast to the rodent families, the newest members of the human KLK family are much less conserved in sequence (23-44% at the protein level) and appear to consist of at least four subfamilies. In addition, like the rat, these genes are expressed at varying levels in a diverse range of tissues although they exhibit quite distinct patterns of expression.

Reliability and accuracy of dermatologists' clinic-based and digital image consultations

BACKGROUND

Telemedicine technology holds great promise for dermatologic health care delivery. However, the clinical outcomes of digital image consultations (teledermatology) must be compared with traditional clinic-based consultations.

OBJECTIVE

Our purpose was to assess and compare the reliability and accuracy of dermatologists' diagnoses and management recommendations for clinic-based and digital image consultations.

METHODS

One hundred sixty-eight lesions found among 129 patients were independently examined by 2 clinic-based dermatologists and 3 different digital image dermatologist consultants. The reliability and accuracy of the examiners' diagnoses and the reliability of their management recommendations were compared.

RESULTS

Proportion agreement among clinic-based examiners for their single most likely diagnosis was 0. 54 (95% confidence interval [CI], 0.46-0.61) and was 0.92 (95% CI, 0. 88-0.96) when ratings included differential diagnoses. Digital image consultants provided diagnoses that were comparably reliable to the clinic-based examiners. Agreement on management recommendations was variable. Digital image and clinic-based consultants displayed similar diagnostic accuracy.

CONCLUSION

Digital image consultations result in reliable and accurate diagnostic outcomes when compared with traditional clinic-based consultations.

Proteomic Profiling of the ECM of Xenograft Breast Cancer Metastases in Different Organs Reveals Distinct Metastatic Niches

Metastasis causes most cancer-related deaths, and one poorly understood aspect of metastatic cancer is the adaptability of cells from a primary tumor to create new niches and survive in multiple, different secondary sites. We used quantitative mass spectrometry to analyze the extracellular matrix (ECM), a critical component of metastatic niches, in metastases to the brain, lungs, liver, and bone marrow, all derived from parental MDA-MB-231 triple-negative breast cancer cells. Tumor and stromal cells cooperated in forming niches; stromal cells produced predominantly core, structural ECM proteins and tumor cells produced a diverse array of ECM-associated proteins, including secreted factors and modulators of the matrix. In addition, tumor and stromal cells together created distinct niches in each tissue. Downregulation of SERPINB1, a protein elevated in brain metastases, led to a reduction in brain metastasis, suggesting that some niche-specific ECM proteins may be involved in metastatic tropism. SIGNIFICANCE: Tumor and stromal cells together create distinct ECM niches in breast cancer metastases to various tissues, providing new insight into how tumor cells adapt to survive in different tissue environments.

Streamlined Protocol for Deep Proteomic Profiling of FAC-sorted Cells and Its Application to Freshly Isolated Murine Immune Cells

Proteomic profiling describes the molecular landscape of proteins in cells immediately available to sense, transduce, and enact the appropriate responses to extracellular queues. Transcriptional profiling has proven invaluable to our understanding of cellular responses; however, insights may be lost as mounting evidence suggests transcript levels only moderately correlate with protein levels in steady state cells. Mass spectrometry-based quantitative proteomics is a well-suited and widely used analytical tool for studying global protein abundances. Typical proteomic workflows are often limited by the amount of sample input that is required for deep and quantitative proteome profiling. This is especially true if the cells of interest need to be purified by fluorescence-activated cell sorting (FACS) and one wants to avoid ex vivo culturing. To address this need, we developed an easy to implement, streamlined workflow that enables quantitative proteome profiling from roughly 2 μg of protein input per experimental condition. Utilizing a combination of facile cell collection from cell sorting, solid-state isobaric labeling and multiplexing of peptides, and small-scale fractionation, we profiled the proteomes of 12 freshly isolated, primary murine immune cell types. Analyzing half of the 3e5 cells collected per cell type, we quantified over 7000 proteins across 12 key immune cell populations directly from their resident tissues. We show that low input proteomics is precise, and the data generated accurately reflects many aspects of known immunology, while expanding the list of cell-type specific proteins across the cell types profiled. The low input proteomics methods we developed are readily adaptable and broadly applicable to any cell or sample types and should enable proteome profiling in systems previously unattainable.

Relationship of mortality to increasing oxygen delivery in patients > or = 50 years of age: a prospective, randomized trial

OBJECTIVE

To investigate the relationship of mortality to early resuscitation using two levels of oxygen delivery (DO2) in critically ill surgical patients > or =50 yrs of age who were stratified into groups: age < or =75 yrs (age 50 to 75 yrs group); and age >75 yrs (age >75 yrs group).

DESIGN

A prospective, randomized trial, continued from a previous project.

SETTING

Surgical intensive care unit, university affiliated.

PATIENTS

Consecutive patients, >50 yrs of age, unable to generate a DO2 of > or =600 mL/min/m2 with fluid resuscitation alone, with a diagnosis of systemic inflammatory response syndrome, sepsis, severe sepsis, septic shock, and/or acute respiratory distress syndrome.

INTERVENTIONS

During the first 24 hrs of resuscitation, patients were randomized to receive fluids, blood transfusions, and vasoactive agents in order to achieve DO2 treatment goals of > or =600 mL/ min/m2 in the protocol group and 450 to 550 mL/min/m2 in the control group.

MEASUREMENTS AND MAIN RESULTS

One hundred five patients completed the study. In patients aged 50 to 75 yrs, the mortality rate was 21% (9/43) in the protocol group and 52% (12/23) in the control group (p=.01, 95% confidence interval of -58% to -4%). In patients >75 yrs of age, the mortality rate was 57% (12/21) in the protocol group and 61% (11/18) in the control group. Oxygen extraction ratios (O2ER) and oxygen consumption values were significantly (p=.02) lower in the age >75 yrs group compared with the age 50 to 75 yrs group.

CONCLUSIONS

Patients 50 to 75 yrs of age receiving a DO2 of > or =600 mL/min/m2 demonstrated a statistically significant (p=.01) improved survival rate over patients in the control group. Patients >75 yrs of age demonstrated no benefit from attempts to increase DO2 to >600 mL/min/m2, and they may have been overtreated as reflected by the lower O2ER values in this age group. Treating to an O2ER that reflects a balance between oxygen consumption and DO2 may be an alternative goal that allows individual titration.

Evaluation of a continuous cardiac output and mixed venous oxygen saturation catheter in critically ill surgical patients

OBJECTIVE

To evaluate the agreement of continuous cardiac output and mixed venous oxygen saturation measurements, obtained with a modified pulmonary artery catheter, with those values obtained by standard intermittent bolus thermodilution and cooximetry.

DESIGN

Prospective, clinical investigation.

SETTING

A surgical intensive care unit in a tertiary referral center.

PATIENTS

Twenty-one adult critically ill surgical patients, requiring pulmonary artery catheter monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A modified pulmonary artery catheter capable of continuous monitoring of cardiac output and mixed venous oxygen saturation was used with either an 8.5-Fr or a 9-Fr introducer. At random intervals, the continuous cardiac output measurement was compared with the cardiac output obtained using standard intermittent bolus thermodilution. The system was calibrated every 24 hrs for mixed venous oxygen saturation monitoring. Each saturation obtained by the laboratory cooximeter was compared with that value recorded using the catheter. Data points for 202 pairs of cardiac output (21 patients, 31 catheters) and 65 pairs of mixed venous oxygen saturation (20 patients, 28 catheters) were obtained. The bias and precision of the cardiac output data were 0.49 and 1.01 L/min, respectively. The agreement between the continuous and bolus values decreased as the cardiac output increased. Heart rate did not affect the agreement between the continuous and bolus techniques. The bias and precision of the mixed venous oxygen saturation data were -0.57% and 3.76%, respectively. The hematocrit did not affect the bias or precision of the venous saturation data over the hematocrit range observed (23.2% to 44.6%). Fewer catheter malfunctions were observed when the catheter was used with a 9-Fr introducer than with an 8.5-Fr introducer.

CONCLUSIONS

The test catheter adequately measures continuous cardiac output and mixed venous oxygen saturation in the clinical setting. Because intermittent bolus thermodilution is not a true "gold standard" for cardiac output determination, new techniques compared with bolus thermodilution may fail to achieve accuracy expectations. A 9-Fr introducer is recommended, as fiberoptic damage may have occurred when the 8.5-Fr introducer was used.

Microemulsion structure and its effect on electrochemical reactions

Changes in the microstructure of oil-in-water microemulsions were identified electrochemically by using ferrocene derivatives, methyl viologen, and ferricyanide as the electroactive probes. Microdroplets as well as the bicontinuous microstructure were detected. This was accomplished by determining diffusion coefficients of the probes. Use of probes of different hydrophobicity/hydrophilicity and charge made it possible to investigate different microenvironments of microemulsions including oil, water, and surfactant/cosurfactant interface. Electrochemical reversibility of the probes was affected by the structure and appeared to reflect the ease of mobility across interphases. Reaction potential (E1/2) of the probes depended on the composition of the microemulsion.

Electron transfer dissociation (ETD): the mass spectrometric breakthrough essential for O-GlcNAc protein site assignments-a study of the O-GlcNAcylated protein host cell factor C1

The development of electron-based, unimolecular dissociation MS, i.e. electron capture and electron transfer dissociation (ECD and ETD, respectively), has greatly increased the speed and reliability of labile PTM site assignment. The field of intracellular O-GlcNAc (O-linked N-acetylglucosamine) signaling has especially advanced with the advent of ETD MS. Only within the last five years have proteomic-scale experiments utilizing ETD allowed the assignment of hundreds of O-GlcNAc sites within cells and subcellular structures. Our ability to identify and unambiguously assign the site of O-GlcNAc modifications using ETD is rapidly increasing our understanding of this regulatory glycosylation and its potential interaction with other PTMs. Here, we discuss the advantages of using ETD, complimented with collisional-activation MS, in a study of the extensively O-GlcNAcylated protein Host Cell Factor C1 (HCF-1). HCF-1 is a transcriptional coregulator that forms a stable complex with O-GlcNAc transferase and controls cell cycle progression. ETD, along with higher energy collisional dissociation (HCD) MS, was employed to assign the PTMs of the HCF-1 protein isolated from HEK293T cells. These include 19 sites of O-GlcNAcylation, two sites of phosphorylation, and two sites bearing dimethylarginine, and showcase the residue-specific, PTM complexity of this regulator of cell proliferation.

SOX2 O-GlcNAcylation alters its protein-protein interactions and genomic occupancy to modulate gene expression in pluripotent cells

The transcription factor SOX2 is central in establishing and maintaining pluripotency. The processes that modulate SOX2 activity to promote pluripotency are not well understood. Here, we show SOX2 is O-GlcNAc modified in its transactivation domain during reprogramming and in mouse embryonic stem cells (mESCs). Upon induction of differentiation SOX2 O-GlcNAcylation at serine 248 is decreased. Replacing wild type with an O-GlcNAc-deficient SOX2 (S248A) increases reprogramming efficiency. ESCs with O-GlcNAc-deficient SOX2 exhibit alterations in gene expression. This change correlates with altered protein-protein interactions and genomic occupancy of the O-GlcNAc-deficient SOX2 compared to wild type. In addition, SOX2 O-GlcNAcylation impairs the SOX2-PARP1 interaction, which has been shown to regulate ESC self-renewal. These findings show that SOX2 activity is modulated by O-GlcNAc, and provide a novel regulatory mechanism for this crucial pluripotency transcription factor.

DOI:http://dx.doi.org/10.7554/eLife.10647.001

Embryos develop from stem cells, which have the ability to mature into any type of cell in the body. The activity of proteins called transcription factors determines whether a stem cell will become a specialized cell type or remain in an immature “pluripotent” state that has the potential to become any cell type. These transcription factors bind to the cell’s DNA to regulate the activity of target genes.

SOX2 is a transcription factor that helps to maintain embryonic stem cells in a pluripotent state. In 2011, a group of researchers showed that a specific sugar molecule was added to SOX2 in mouse embryonic stem cells, in a process called O-GlcNAcylation. Now, Myers, Peddada et al. – including the researchers who performed the 2011 study – have studied the effects of this SOX2 modification in more detail.

Transcription factors have two major activities – they bind to DNA and recruit other proteins that can turn target genes on or off. Myers, Peddada et al. found that, in pluripotent stem cells, a complex pattern of O-GlcNAcylation is present on SOX2 in a region that is responsible for recruiting other proteins. In addition, SOX2 O-GlcNAcylation decreases when stem cells are directed to become a new cell type.

Further experiments investigated gene activity in stem cells that contained a mutant form of SOX2 that cannot be O-GlcNAc modified. In these cells, genes that help to maintain the cell in a pluripotent state were more active than in normal cells. The mutant form of SOX2 was altered in its ability to bind DNA and to associate with proteins that control gene activity.

Myers, Peddada et al.’s findings raise several questions. Does O-GlcNAcylation control the activity of SOX2 in other cell types, such as neurons and cancer cells, in which this modification can be detected on SOX2? Why does a modification on the portion of the SOX2 that is thought to interact with other proteins affect SOX2 DNA binding activity? Finally, understanding how O-GlcNAcylation is employed to regulate SOX2 activity in response to developmental cues remains a major challenge.

DOI:http://dx.doi.org/10.7554/eLife.10647.002

Frequency of mortality and myocardial infarction during maximizing oxygen delivery: a prospective, randomized trial

OBJECTIVES

To determine the frequency of myocardial infarction and mortality during treatment that increased oxygen delivery (DO2) to > or = 600 mL/min/m2. To define the characteristics of patients achieving a high DO2 without inotropes in order to guide future studies.

DESIGN

A prospective, randomized, controlled trial.

SETTING

Two surgical intensive care units at The Queen's Medical Center in the University of Hawaii Surgical Residency Program.

PATIENTS

Eighty-nine surgical patients (> or = 18 yrs of age), who were admitted to a surgical intensive care unit and who required pulmonary artery catheter monitoring, were selected for the study. Diagnoses included sepsis, septic shock, adult respiratory distress syndrome, or hypovolemic shock. Patients facing imminent death were excluded from the study.

INTERVENTIONS

The treatment group received fluid boluses, blood products, and inotropes, as needed, to achieve a DO2 of > or = 600 mL/min/m2 in the first 24 hrs. Using the same interventions, we treated the control group to reach a DO2 of 450 to 550 mL/min/m2.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic measurements were obtained every 4 hrs until the pulmonary artery catheter was removed. DO2 and oxygen consumption were calculated by standard formulas. Serial creatine kinase myocardial fraction and electrocardiograms were documented for the first 48 hrs after study entry and for any new onset of arrhythmia or increasing hemodynamic instability. The patients who generated a high DO2 (> or = 600 mL/min/m2) with only preload treatment were reflective of patients with better cardiac reserve and low mortality rates. These patients, from both treatment and control groups, were excluded in the final analysis. The treatment group who received inotropes to achieve the high DO2 had a 14% mortality rate. Those patients who failed to achieve the high DO2 had a 67% mortality rate, and the control group who achieved a normal DO2 had a 62% mortality rate (p = .005). The frequency of myocardial infarction after study entry was 5.6% (five of 89 patients). This rate was not higher among the groups who received inotropes. Logistic regression analysis showed that age of > or = 50 yrs could be used to classify patients as not self-generating, with an 83% chance of being correct.

CONCLUSIONS

The group that required catecholamines to achieve a DO2 of > or = 600 mL/min/m2 had a lower mortality rate, with no increase in the frequency of myocardial infarction. Future prospective, controlled trials examining select groups of patients (age > or = 50 yrs) may demonstrate a difference between control and treatment groups by eliminating the majority of patients who generate the high DO2 with only preload augmentation.

Glucose and lactate oxidation rates in the fetal lamb

Both glucose and lactate are nutrients of the ovine fetus. Each may be used by the fetus as a fuel for oxidation or as a source of carbon for energy storage and net tissue accretion. The present report describes the oxidation rates of glucose and lactate in vivo for the fetal lamb over a relatively short time period. The fraction of fetal glucose or lactate oxidized was defined as the ratio of 14CO2 excretion across the umbilical circulation to the net entry of [14C]glucose or [14C]lactate into fetal tissues. The fraction of glucose oxidized over a 3-hr study averaged 61.2%, accounting for 2.55 mg X min-1 X kg-1 of glucose oxidized and for 28% of the simultaneous net oxygen uptake. The fraction of lactate oxidized averaged 71.5%, accounting for 4.12 mg X min-1 X kg-1 of lactate oxidized. Oxidation fractions and rates for both glucose and lactate increased with their concentrations in fetal blood suggesting sparing of other fuels for oxidation at higher glucose and lactate concentrations.

Auditory and visual threshold effects of marihuana in man

Auditory and visual thresholds were measured before and after smoking marihuana ( Cannabis sativa L.) for 20 experienced Ss. Marihuana was administered until S reported experiencing a “high.” Results indicated no effect on visual acuity, whereas one of three auditory measurements differentiated between marihuana and control Ss.

Spatiotemporally-resolved mapping of RNA binding proteins via functional proximity labeling reveals a mitochondrial mRNA anchor promoting stress recovery

Proximity labeling (PL) with genetically-targeted promiscuous enzymes has emerged as a powerful tool for unbiased proteome discovery. By combining the spatiotemporal specificity of PL with methods for functional protein enrichment, we show that it is possible to map specific protein subclasses within distinct compartments of living cells. In particular, we develop a method to enrich subcompartment-specific RNA binding proteins (RBPs) by combining peroxidase-catalyzed PL with organic-aqueous phase separation of crosslinked protein-RNA complexes (“APEX-PS”). We use APEX-PS to generate datasets of nuclear, nucleolar, and outer mitochondrial membrane (OMM) RBPs, which can be mined for novel functions. For example, we find that the OMM RBP SYNJ2BP retains specific nuclear-encoded mitochondrial mRNAs at the OMM during translation stress, facilitating their local translation and import of protein products into the mitochondrion during stress recovery. Functional PL in general, and APEX-PS in particular, represent versatile approaches for the discovery of proteins with novel function in specific subcellular compartments.

Proximity labeling is used to map and discover proteins in specific subcellular compartments. Here the authors combine APEX-mediated proximity labeling with organic-aqueous phase separation to identify nuclear, nucleolar, and outer mitochondrial membrane RNA binding proteins.

More than one previous cesarean delivery: a 5-year experience with 435 patients

OBJECTIVE

To evaluate the obstetric outcome of patients who have had more than one previous cesarean delivery, and to compare it with that of patients with one previous cesarean.

METHODS

Medical records of 435 women with more than one previous cesarean and 1206 with one previous cesarean, and who delivered at our institution in the period 1987-1991, were reviewed retrospectively. All adverse outcomes related to uterine wound separation identified in medical records were reviewed individually. Statistical analysis of outcome used chi 2 test, Fisher exact test, and odds ratios with 95% confidence intervals.

RESULTS

Uterine wound separation occurred in nine of 435 patients with more than one previous cesarean compared with 16 of 1206 with a single previous cesarean (2.1 versus 1.3%, not significant). Of those undergoing a trial of labor, separations occurred in six of 302 and 12 of 1110 patients with more than one and a single previous operation, respectively (2.0 versus 1.1%, not significant). Vaginal birth after cesarean was successful less often in women with more than one previous cesarean than in those with one previous operation (64 versus 77%, P < .05). Important adverse outcomes were infrequent and not related to the number of previous cesareans.

CONCLUSION

Our findings support allowing a trial of labor for patients with more than one previous cesarean delivery under conditions that permit prompt recognition and treatment of emergencies.

The relationship between autoantibodies and intrauterine growth retardation in hypertensive disorders of pregnancy

Abnormal levels of autoantibodies have recently been demonstrated in patients with hypertensive disorders of pregnancy and patients whose fetuses have intrauterine growth retardation. We determined total immunoglobulin levels (immunoglobulin G, immunoglobulin M, and immunoglobulin A) and a broad panel of autoantibodies (six antiphospholipid, four antihistone, and four antipolynucleotide antibodies) in 50 normotensive pregnant females, 19 patients with preeclampsia, and 18 patients with chronic hypertension to examine the relationship to intrauterine growth retardation. Mothers who were delivered of infants with intrauterine growth retardation demonstrated significantly more autoantibody abnormalities in the two hypertensive groups and in the normotensive control group as compared with patients delivered of appropriately grown infants. The most frequently observed autoantibody abnormalities were antiphospholipid antibodies and the most frequently observed among those were immunoglobulin G isotypes. Total immunoglobulin levels in both hypertensive and normotensive groups were identical. These results suggest a close association between the degree of B-cell activation and both severity of hypertensive diseases and development of intrauterine growth retardation in their offspring.

Compartmentalized expression of kallikrein 4 (KLK4/hK4) isoforms in prostate cancer: nuclear, cytoplasmic and secreted forms

The prostate-specific antigen-related serine protease gene, kallikrein 4 (KLK4), is expressed in the prostate and, more importantly, overexpressed in prostate cancer. Several KLK4 mRNA splice variants have been reported, but it is still not clear which of these is most relevant to prostate cancer. Here we report that, in addition to the full-length KLK4 (KLK4-254) transcript, the exon 1 deleted KLK4 transcripts, in particular, the 5'-truncated KLK4-205 transcript, is expressed in prostate cancer. Using V5/His6 and green fluorescent protein (GFP) carboxy terminal tagged expression constructs and immunocytochemical approaches, we found that hK4-254 is cytoplasmically localized, while the N-terminal truncated hK4-205 is in the nucleus of transfected PC-3 prostate cancer cells. At the protein level, using anti-hK4 peptide antibodies specific to different regions of hK4-254 (N-terminal and C-terminal), we also demonstrated that endogenous hK4-254 (detected with the N-terminal antibody) is more intensely stained in malignant cells than in benign prostate cells, and is secreted into seminal fluid. In contrast, for the endogenous nuclear-localized N-terminal truncated hK4-205 form, there was less difference in staining intensity between benign and cancer glands. Thus, KLK4-254/hK4-254 may have utility as an immunohistochemical marker for prostate cancer. Our studies also indicate that the expression levels of the truncated KLK4 transcripts, but not KLK4-254, are regulated by androgens in LNCaP cells. Thus, these data demonstrate that there are two major isoforms of hK4 (KLK4-254/hK4-254 and KLK4-205/hK4-205) expressed in prostate cancer with different regulatory and expression profiles that imply both secreted and novel nuclear roles.

Identification and validation of the pathways and functions regulated by the orphan nuclear receptor, ROR alpha1, in skeletal muscle

The retinoic acid receptor-related orphan receptor (ROR) alpha has been demonstrated to regulate lipid metabolism. We were interested in the RORα1 dependent physiological functions in skeletal muscle. This major mass organ accounts for ∼40% of the total body mass and significant levels of lipid catabolism, glucose disposal and energy expenditure. We utilized the strategy of targeted muscle-specific expression of a truncated (dominant negative) RORα1ΔDE in transgenic mice to investigate RORα1 signaling in this tissue. Expression profiling and pathway analysis indicated that RORα influenced genes involved in: (i) lipid and carbohydrate metabolism, cardiovascular and metabolic disease; (ii) LXR nuclear receptor signaling and (iii) Akt and AMPK signaling. This analysis was validated by quantitative PCR analysis using TaqMan low-density arrays, coupled to statistical analysis (with Empirical Bayes and Benjamini–Hochberg). Moreover, westerns and metabolic profiling were utilized to validate the genes, proteins and pathways (lipogenic, Akt, AMPK and fatty acid oxidation) involved in the regulation of metabolism by RORα1. The identified genes and pathways were in concordance with the demonstration of hyperglycemia, glucose intolerance, attenuated insulin-stimulated phosphorylation of Akt and impaired glucose uptake in the transgenic heterozygous Tg-RORα1ΔDE animals. In conclusion, we propose that RORα1 is involved in regulating the Akt2-AMPK signaling pathways in the context of lipid homeostasis in skeletal muscle.

Identification and Characterization of KLK14, a Novel Kallikrein Serine Protease Gene Located on Human Chromosome 19q13.4 and Expressed in Prostate and Skeletal Muscle

The kallikreins are a subfamily of serine proteases encoded in human, mouse, and rat by highly conserved tightly clustered multigene families. Here we report the identification and characterization of KLK14, a novel kallikrein gene located within the human kallikrein locus at 19q13.4. KLK14 is approximately 5.4 kb in length spanning seven exons and, by Northern blot analysis, transcribes two alternative transcripts present only in prostate (1.5 kb) and skeletal muscle (1.9 kb). The protein product, K14, predicted to be a 251-amino-acid secreted serine protease with trypsin-like substrate specificity, is translated in vitro with a molecular mass of approximately 31 kDa. In situ hybridization revealed that, in prostate, KLK14 is expressed by both benign and malignant glandular epithelial cells, thus exhibiting an expression pattern similar to that of two other prostatic kallikreins, KLK2 and KLK3, which encode K2 and prostate-specific antigen, respectively.

Human RNA Polymerase II Promoter Recruitment in Vitro Is Regulated by O-Linked N-Acetylglucosaminyltransferase (OGT)

Although the O-linked N-acetylglucosamine (O-GlcNAc) modification of the RNA polymerase II C-terminal domain was described 20 years ago, the function of this RNA polymerase II (pol II) species is not known. We show here that an O-GlcNAcylated pol II species (pol IIγ) exists on promoters in vitro Inhibition of O-GlcNAc-transferase activity and O-GlcNAcylation prevents pol II entry into the promoter, and O-GlcNAc removal from pol II is an ATP-dependent step during initiation. These data indicate that O-GlcNAc-transferase activity is essential for RNA pol II promoter recruitment and that pol II goes through a cycling of O-GlcNAcylation at the promoter. Mass spectrometry shows that serine residues 2 and 5 of the pol II C-terminal domain are O-GlcNAcylated, suggesting an overlap with the transcription factor IIH (TFIIH)-dependent serine 5 phosphorylation events during initiation and P-TEFb (positive transcriptional elongation factor b) events during elongation. These data provide unexpected and important insights into the role of a previously ill-defined species of RNA polymerase II in regulating transcription.