Good quality of life before cardiac arrest predicts good quality of life after resuscitation

BACKGROUND

The survival rate of cardiac arrest patients is increasing. Our aim was to compare the quality of life before and after cardiac arrest and analyse the factors associated with outcome.

METHODS

All adult cardiac arrest patients admitted to the Tampere University Hospital intensive care unit between 2009 and 2011 were included in a retrospective follow-up study if surviving to discharge and were asked to return a questionnaire after 6 months. Data on patient demographics and pre-arrest quality of life were retrieved from medical records. Data are given as means (SD) or medians [Q₁ , Q₃ ]. We used logistic regression to identify factors associated with better quality of life after cardiac arrest.

RESULTS

Six months after cardiac arrest, 36% (79/222) were alive and 70% (55/79) of those patients completed the follow-up EuroQoL (EQ-5D) quality of life questionnaire. Median values for the EQ-5D before and after cardiac arrest were 0.89 [0.63, 1] and 0.89 [0.62, 1], respectively (P = 0.75). Only the EQ-5D prior to cardiac arrest was associated with better quality of life afterwards (OR 1.2; 95% CI 1.0-1.3; P = 0.02).

CONCLUSIONS

Quality of life remained good after cardiac arrest especially in those patients who had good quality of life before cardiac arrest.

Effect of Six-Month Diet Intervention on Sleep among Overweight and Obese Men with Chronic Insomnia Symptoms: A Randomized Controlled Trial

Growing evidence suggests that diet alteration affects sleep, but this has not yet been studied in adults with insomnia symptoms. We aimed to determine the effect of a six-month diet intervention on sleep among overweight and obese (Body mass index, BMI ≥ 25 kg/m²) men with chronic insomnia symptoms. Forty-nine men aged 30–65 years with chronic insomnia symptoms were randomized into diet (n = 28) or control (n = 21) groups. The diet group underwent a six-month individualized diet intervention with three face-to-face counseling sessions and online supervision 1–3 times per week; 300–500 kcal/day less energy intake and optimized nutrient composition were recommended. Controls were instructed to maintain their habitual lifestyle. Sleep parameters were determined by piezoelectric bed sensors, a sleep diary, and a Basic Nordic sleep questionnaire. Compared to the controls, the diet group had shorter objective sleep onset latency after intervention. Within the diet group, prolonged objective total sleep time, improved objective sleep efficiency, lower depression score, less subjective nocturnal awakenings, and nocturia were found after intervention. In conclusion, modest energy restriction and optimized nutrient composition shorten sleep onset latency in overweight and obese men with insomnia symptoms.

Effects of exercise and diet interventions on obesity-related sleep disorders in men: study protocol for a randomized controlled trial

BACKGROUND

Sleep is essential for normal and healthy living. Lack of good quality sleep affects physical, mental and emotional functions. Currently, the treatments of obesity-related sleep disorders focus more on suppressing sleep-related symptoms pharmaceutically and are often accompanied by side effects. Thus, there is urgent need for alternative ways to combat chronic sleep disorders. This study will investigate underlying mechanisms of the effects of exercise and diet intervention on obesity-related sleep disorders, the role of gut microbiota in relation to poor quality of sleep and day-time sleepiness, as well as the levels of hormones responsible for sleep-wake cycle regulation.

METHODS/DESIGN

Participants consist of 330 (target sample) Finnish men aged 30 to 65 years. Among them, we attempt to randomize 180 (target sample) with sleep disorders into exercise and diet intervention. After screening and physician examination, 101 men with sleep disorders are included and are randomly assigned into three groups: exercise (n = 33), diet (n = 35), and control (n = 33). In addition, we attempt to recruit a target number of 150 healthy men without sleep disorders as the reference group. The exercise group undergoes a six-month individualized progressive aerobic exercise program based on initial fitness level. The diet group follows a six month specific individualized diet program. The control group and reference group are asked to maintain their normal activity and diet during intervention. Measurements are taken before and after the intervention. Primary outcomes include objective sleep measurements by polysomnography and a home-based non-contact sleep monitoring system, and subjective sleep evaluation by questionnaires. Secondary outcome measures include anthropometry, body composition, fitness, sleep disorder-related lifestyle risk factors, composition of gut microbiota and adipose tissue metabolism, as well as specific hormone and neurotranmitter levels and inflammatory biomarkers from venous blood samples.

DISCUSSION

It is expected that the improvement of sleep quality after exercise and diet intervention will be evident both in subjective and objective measures of quality of sleep. Additionally, the change of sleep quality induced by exercise and diet intervention is expected to be related to the changes in specific hormones and inflammatory biomarkers, and in the composition of gut microbiota.

Lactate concentrations in the rectal lumen in patients in early septic shock

BACKGROUND

Previously, we observed that rectal luminal lactate was higher in non-survivors compared with survivors of severe sepsis or septic shock persisting >24 h. The present study was initiated to further investigate this tentative association between rectal luminal lactate and mortality in a larger population of patients in early septic shock.

METHODS

A prospective observational multicentre study of 130 patients with septic shock at six general ICU's of university hospitals. Six to 24 h after the onset of septic shock, the concentration of lactate in the rectal lumen was estimated by a 4-h equilibrium dialysis. Dialysate concentrations of lactate were determined using an auto-analyser.

RESULTS

The overall 30-day mortality was 32%, with age and Simplified acute physiology scores II and sequential organ failure assessment scores being significantly higher in non-survivors. In contrast, there were no differences in concentrations of lactate in the rectal lumen [2.2 (1.4-4.1) and 2.8 (1.6-5.1) mmol/l (P=0.34)] (medians and 25th-75th percentiles) or arterial blood [2.1 (1.4-4.2) and 2.0 (1.3-3.2) mmol/l (P=0.15)] between non-survivors and survivors. The rectal-arterial difference of the lactate concentration was higher in survivors. There were no differences in blood pressure, noradrenaline dose or central venous oxygen saturation between the groups.

CONCLUSION

In this prospective, observational study of unselected patients with early septic shock, there was no difference in the concentration of lactate in the rectal lumen between non-survivors and survivors.

TRIAL REGISTRATION

Clinicaltrials.gov (no: NCT00197938).

Prehospital therapeutic hypothermia for comatose survivors of cardiac arrest: a randomized controlled trial

BACKGROUND

Intravenous infusion of ice-cold fluid is considered a feasible method to induce mild therapeutic hypothermia in cardiac arrest survivors. However, only one randomized controlled trial evaluating this treatment exists. Furthermore, the implementation rate of prehospital cooling is low. The aim of this study was to evaluate the efficacy and safety of this method in comparison with conventional therapy with spontaneous cooling often observed in prehospital patients.

METHODS

A randomized controlled trial was conducted in a physician-staffed helicopter emergency medical service. After successful initial resuscitation, patients were randomized to receive either +4 degrees C Ringer's solution with a target temperature of 33 degrees C or conventional fluid therapy. As an endpoint, nasopharyngeal temperature was recorded at the time of hospital admission.

RESULTS

Out of 44 screened patients, 19 were analysed in the treatment group and 18 in the control group. The two groups were comparable in terms of baseline characteristics. The core temperature was markedly lower in the hypothermia group at the time of hospital admission (34.1+/-0.9 degrees C vs. 35.2+/-0.8 degrees C, P<0.001) after a comparable duration of transportation. Otherwise, there were no significant differences between the groups regarding safety or secondary outcome measures such as neurological outcome and mortality.

CONCLUSION

Spontaneous cooling alone is insufficient to induce therapeutic hypothermia before hospital admission. Infusion of ice-cold fluid after return of spontaneous circulation was found to be well tolerated and effective. This method of cooling should be considered as an important first link in the 'cold chain' of prehospital comatose cardiac arrest survivors.

Physiological and morphological responses to water stress in two Acacia species from contrasting habitats

Container-grown seedlings of Acacia tortilis Forsk. Hayne and A. xanthophloea Benth. were watered either every other day (well watered) or every 7 days (water-stressed) for 1 year in a greenhouse. Total plant dry mass (T(dm)), carbon allocation and water relations were measured monthly. Differences in leaf area (LA) accounted for differences in T(dm) between the species, and between well-watered and water-stressed plants. Reduction in LA as a result of water stress was attributed to reduced leaf initiation, leaf growth rate and leaf size. When subjected to prolonged water stress, Acacia xanthophloea wilted more rapidly than A. tortilis and, unlike A. tortilis, lost both leaves and branches. These differences between species were attributed to differences in the allocation of carbon between leaves and roots and in the ability to adjust osmotically. Rapid recovery in A. xanthophloea following the prolonged water-stress treatment was attributed to high cell wall elasticity. Previous exposure to water stress contributed to water-stress resistance and improved recovery after stress.

Analysis of depth profiling data obtained by confocal Raman microspectroscopy

The nominal depth resolution achieved in confocal Raman microscopy is on the order of a few micrometers. Often, however, the depth resolution is decreased by light refraction at the sample surface. The problem can be avoided with the use of an immersion objective and index matching oils. Through this intervention the instrument point-spread function (PSF) can be assumed to be independent of the depth of focus in the sample, and spatially invariant depth profiles can be acquired. In this work the instrument PSF was determined by measuring a depth profile of a thick uniform sample and calculating the first derivative of the depth profile curve. The first-derivative method was also used to determine sample thickness. Convolution with the PSF makes it possible to simulate the behavior of the instrument with different sample functions. It is also possible to use the instrument PSF to deconvolve depth-profiling data. Deconvolution reduces the blurring effect of the instrument and increases the depth resolution. Deconvolution can also be used in analysis of the sample surface position and in layer structure analysis. In this paper we show how the convolution integral can be used with the immersion sampling technique to determine the PSF and how the sample thickness can be determined.

Characterization of wet massing behavior of silicified microcrystalline cellulose and alpha-lactose monohydrate using near-infrared spectroscopy

The purpose of this study was to investigate the energetic state of water in silicified microcrystalline cellulose (SMCC) and alpha-lactose monohydrate wet masses using near-infrared (NIR) spectroscopy. The applicability of NIR spectroscopy to studying pharmaceutical wet masses at a wide moisture range was evaluated in comparison with mixer torque rheometry (MTR). With increasing moisture content changes in the physical properties of the samples resulted in an apparent increase in log (1/R) throughout the whole spectrum. The upward displacement of baseline and the relative height of water bands were greatest with materials that had a poor liquid-retention capacity. In the case of SMCC and 1:1 mixture of SMCC and alpha-lactose monohydrate, the height of the baseline-corrected water bands increased linearly at low moisture contents, thereafter achieving a plateau stage. According to the MTR results, the plateau stage of the band heights indicated a capillary state of liquid saturation. The second derivative spectrum was capable of distinguishing monohydrate, absorbed, and adsorbed water, which overlapped in the absorbance spectrum. When water was absorbed to the internal structure of the material (SMCC), the water bands were first seen at higher wavelengths, then followed by a shift to lower wavelengths. When water was only adsorbed onto the surface of the particles (glass ballotini), the water bands were seen directly in the region of bulk water.

Effects of dobutamine on splanchnic tissue perfusion during partial superior mesenteric artery occlusion

OBJECTIVE

To evaluate the effects of dobutamine and fluid treatment on splanchnic hemodynamics and tissue oxygenation during partial superior mesenteric artery occlusion.

DESIGN

Prospective, open randomized, full-factorial design.

SETTING

University research laboratory.

SUBJECTS

Forty-eight female pigs.

INTERVENTIONS

In 24 anesthetized pigs (ischemic group), superior mesenteric artery (SMA) blood flow was reduced to 30% from the baseline for 120 mins; 24 pigs (sham group) served as nonischemic controls. The animals were further assigned into four treatment arms. In the control arm, the animals were administered only basic fluid therapy. In the fluid therapy arm, pulmonary artery occlusion pressure was maintained at 10 mm Hg with fluids. In the dobutamine treatment arm, dobutamine hydrochloride was infused at a dose of 10 microg/min/kg. In the combined dobutamine-fluid therapy arm, dobutamine at 10 microg/min/kg was administered and pulmonary artery occlusion pressure was maintained at 10 mm Hg with fluids.

MEASUREMENTS AND MAIN RESULTS

Systemic and regional hemodynamics and oxygen transport, as well as jejunal intramucosal pH, intramucosal-arterial PCO2 gradient, and portal venous-arterial lactate gradient were measured. Ischemia did not modify the effects of fluids or dobutamine on systemic hemodynamics and oxygen transport. Dobutamine-treated animals had a higher cardiac index compared with control animals (218 +/- 22 vs. 135 +/- 13 mL/min/kg; p = .012), and the effect was enhanced when dobutamine was combined with fluid treatment (365 +/- 23 mL/ min/kg; p = .019). Fluid treatment alone did not influence cardiac index, whereas it increased SMA blood flow compared with control groups (15 +/- 2 vs. 12 +/- 2 mL/min/kg; p = .023). Dobutamine also decreased the proportion of SMA blood flow of cardiac output compared with control groups (6 +/- 1 vs. 9% +/- 1%; p = .024). Other treatments had no effect on SMA blood flow. Ischemia increased intramucosal-arterial Pco2 gradient to 54.8 +/- 10.7 torr (7.31 +/- 1.43 kPa) (p = .002 vs. sham control) and decreased intramucosal pH to 7.13 +/- 0.06 (p = .028 vs. sham control). In the ischemic animals, dobutamine without fluid therapy reduced intramucosal pH further to 7.00 +/- 0.09 (p = .023 vs. ischemic control) and increased portal venous-arterial lactate gradient (p = .033).

CONCLUSIONS

Dobutamine alone worsened splanchnic tissue perfusion during partial superior mesenteric artery occlusion. As compared with fluid treatment alone, the combination of fluid and dobutamine therapy did not improve tissue perfusion.

In-line moisture measurement during granulation with a four-wavelength near infrared sensor: an evaluation of particle size and binder effects

Factors affecting in-line near infrared (NIR) moisture measurement with a four-wavelength sensor were evaluated (choice of binder used in granulation liquid and the increase in particle size). An entire NIR spectrum is not necessary for the measurement of water, and often the use of only a few NIR wavelengths around the water band enables reliable and high-speed detection of moisture. Glass ballotini and microcrystalline cellulose (MCC) were used as model test materials. The binders studied were poly[1-(2-oxo-1-pyrrolidinyl)ethylene] (PVP) and gelatin. Full off-line NIR spectra of test materials at different levels of binder solutions were measured. The major spectral features for both the binders were bands around 1700 nm (first overtones CH related stretches) and 2200 nm (combination bands). Gelatin also had an NH band around 1500 nm (first overtones of NH stretches) and combination bands at about 2050 nm. Particle size effects were observed as an increase in spectra baseline. All these factors should be considered when choosing NIR wavelengths used for detection of water with a fixed wavelength set-up. A robust calibration model enables the development of in-process control of wet granulation processes.

Next generation fluidized bed granulator automation

A system for fluidized bed granulator automation with in-line multichannel near infrared (NIR) moisture measurement and a unique air flow rate measurement design was assembled, and the information gained was investigated. The multivariate process data collected was analyzed using principal component analysis (PCA). The test materials (theophylline and microcrystalline cellulose) were granulated and the calibration behavior of the multichannel NIR set-up was evaluated against full Fourier Transform (FT) NIR spectra. Accurate and reliable process air flow rate measurement proved critical in controlling the granulation process. The process data describing the state of the process was projected in two dimensions, and the information from various trend charts was outlined simultaneously. The absorbence of test material at correction wavelengths (NIR region) and the nature of material-water interactions affected the detected in-line NIR water signal. This resulted in different calibration models for the test materials. Development of process analytical methods together with new data visualization algorithms creates new tools for in-process control of the fluidized bed granulation.

Soluble and membrane-bound catechol-O-methyltransferase in normal and malignant mammary gland

The levels of 26 kDa-soluble (S) and 30 kDa-membrane-bound (MB) catechol-O-methyltransferase (COMT) polypeptides were determined in paired samples from normal and neoplastic breast tissue of 32 patients with breast cancer. Immunohistochemical staining showed that the COMT reaction in normal mammary tissue was restricted to the epithelial cells in the ducti and lobuli, whereas in the tumors a strong reaction was also seen in the malignant cells. The amounts of COMT proteins in tumors could not be correlated with various clinical or pathological parameters. Quantitative immunoblotting analysis revealed that the total amount of COMT proteins in tumors was more than 50% higher than in respective normal samples in 26 out of 32 patients. Five cases showed less than a 50% difference and in one case less COMT was detected in the tumor. In most cases the amount of both S- and MB-COMT forms was increased. The average amount of total COMT was 178 +/- 57 pg/microg total protein in normal tissue and 566 +/- 94 pg/microg total protein in tumor. Respective values for S-COMT were 137 +/- 52 pg/microg total protein in normal tissue and 369 +/- 62 pg/microg total protein in tumor and for MB-COMT 41 +/- 10 and 197 +/- 41 pg/microg total protein, respectively. Analysis of COMT-specific transcripts suggested that the COMT enzyme level in tumors is determined in some cases by transcriptional and in some cases by post-transcriptional mechanisms.

Angiotensin converting enzyme inhibition has no effect on blood pressure and splanchnic perfusion after cardiac surgery

PURPOSE

The purpose of this study was to study the effect of the angiotensin-converting enzyme inhibitor, enalaprilat, on blood pressure and splanchnic perfusion after cardiac surgery.

MATERIALS AND METHODS

Sixteen patients were studied after coronary artery bypass grafting. After admission to the intensive care unit, a 30-minute baseline measurement of systemic hemodynamics, oxygen transport, and gastric tonometry was performed. In 6 of 10 patients receiving enalaprilat and in each of 6 control patients, regional (splanchnic and leg) blood flows were measured also. After the baseline measurement period, 10 patients received a 0.5 mg bolus of enalaprilat and thereafter an incremental infusion of enalaprilat up to a total dose of 10 mg (mean 8.3; range 4 to 10 mg) was continued to reduce the mean arterial pressure (MAP) to 70 to 80 mm Hg. A 30-minute measurement period was repeated 2 to 3 hours after the first measurement period. In the control group, the second measurement was performed at corresponding time points.

RESULTS

Though MAP decreased in the enalaprilat group (enalaprilat 99 +/- 14 mm Hg v 89 +/- 21 mm Hg, P < .05; control 95 +/- 13 mm Hg v82 +/- 10 mm Hg, P = NS) in only 4 of 10 patients was the targeted MAP reduction achieved. No significant changes were observed either in systemic or regional blood flows. Systemic, pulmonary, and femoral vascular resistance indices decreased significantly in both groups. Gastric-arterial PCO2 difference did not change in either groups. Angiotensin-converting enzyme activity decreased in the enalaprilat group (10.0 +/- 2.3 v 1.3 +/- 0.3 U x l(-1), P < .01), but plasma renin and endothelin-1 concentrations did not change in either group.

CONCLUSIONS

The effect of enalaprilat on blood pressure was poor and it had no beneficial effects on splanchnic circulation. Renin-angiotensin activation is not a major factor in hypertension and splanchnic perfusion after cardiac surgery.

Molecular genetic study of Finns with hypoalphalipoproteinemia and hyperalphalipoproteinemia: a novel Gly230 Arg mutation (LCAT[Fin]) of lecithin:cholesterol acyltransferase (LCAT) accounts for 5% of cases with very low serum HDL cholesterol levels

In an attempt to identify genetic factors underlying extreme alterations of serum HDL cholesterol (HDL-C) concentrations, we examined two probands with HDL-C levels <0.2 mmol/L and subsequently screened two large cohorts of smoking men, one with very low (0.2 to 0.7 mmol/L, n=156) and the other with elevated (1.9 to 3.6 mmol/L, n=160) HDL-C levels, for the newly detected mutations as well as some other mutations proposed to affect HDL-C levels. One of the probands had corneal opacities, microalbuminuria, hypertriglyceridemia, and reduced LDL apoprotein B concentration; the other had anemia and presented with stomatocytosis in his peripheral blood. The first proband was found to be homozygous for a novel LCAT Gly230Arg (LCAT[Fin]) mutation, and the second was homozygous for an Arg399Cys mutation we described previously. Transient expression of the mutant LCAT(Fin) cDNA in COS cells disclosed markedly diminished LCAT enzyme activity. In the low-HDL-C group of men (n=156), 8 carriers of LCAT(Fin) and 1 carrier of the LCAT Arg399Cys were identified. In addition, the frequency of the lipoprotein lipase (LPL) Asn291Ser mutation was significantly (P<.05) higher in the low-HDL-C group (4.8%) than in the high-HDL-C group (1.6%). In addition, we identified 1 carrier of the intron 14G-->A mutation of cholesterol ester transfer protein (CETP) in the high-HDL-C group and subsequently demonstrated cosegregation of the mutant allele with elevated HDL-C levels in the proband's family. In conclusion, we have identified a novel LCAT gene Gly230Arg mutation (LCAT[Fin]), which, together with the LPL Asn291Ser mutation, represents a relatively common genetic cause of diminishing HDL-C levels, at least among Finns. This article also reports occurrence of a CETP mutation in subjects having non-Japanese roots.

Diurnal patterns of CO2 and H2O exchange of the Arctic sedges Eriophorum angustifolium and E. vaginatum (Cyperaceae)

Eriophorum vaginatum and E. angustifolium are dominant arctic sedges of the well-drained tussock tundra and the permanently flooded wet-sedge tundra, respectively. We determined diurnal courses of gas exchange and water relations of the two species in their natural habitat and compared their responses to changes in light, air temperature, and humidity. Mean photosynthetic response to light was similar between E. angustifolium and E. vaginatum and carbon gain in both species was light limited during most of the growing season. On sunny and dry days, both species closed stomata in response to high leaf-to-air vapor pressure deficits. Even though E. angustifolium was growing in standing water, it exhibited a tighter control of transpirational water loss and had lower hydraulic conductivity in the soil-root-shoot pathway than E. vaginatum. The different response pattern between the two species is discussed in the context of differences in habitat conditions.

Expression and regulation of the human and mouse aspartylglucosaminidase gene

Aspartylglucosaminidase (AGA) is a lysosomal enzyme that catalyzes one of the final steps in the degradation of N-linked glycoproteins. Here we have analyzed the tissue-specific expression and regulation of the human and mouse AGA genes. We isolated and characterized human and mouse AGA 5'-flanking sequences including the promoter regions. Primer extension assay revealed multiple transcription start sites in both genes, characteristic of a housekeeping gene. The cross-species comparison studies pinpointed an approximately 450-base pair (bp) homologous region in the distal promoter. In the functional analysis of human AGA 5' sequence, the critical promoter region was defined, and an additional upstream region of 181 bp exhibiting an inhibitory effect on transcription was identified. Footprinting and gel shift assays indicated protein binding to the core promoter region consisting of two Sp1 binding sites, which were sufficient to produce basal promoter activity in the functional studies. The results also suggested the binding of a previously uncharacterized transcription factor to a 23-bp stretch in the inhibitory region.

Expression and intracellular localization of catechol O-methyltransferase in transfected mammalian cells

The intracellular localization of soluble and membrane-bound isoforms of rat and human catechol O-methyltransferase (COMT) was studied by expressing the recombinant COMT proteins either separately or together in mammalian cell lines (HeLa and COS-7 cells) and in rat primary neurons. The distribution of soluble and membrane-bound COMT enzyme was visualized by immunocytochemistry. For comparison, the localization of native COMT was studied in rat C6 glioma cells by immunoelectron microscopy. Staining of cells expressing membrane-bound COMT with a COMT-specific antiserum revealed an immunofluorescence signal in intracellular reticular structures and in the nuclear membrane. Double-staining of the cells with antisera against proteins specific for the rough endoplasmic reticulum indicated that they colocalized with membrane-bound COMT, suggesting that it resided in the endoplasmic reticulum. Notably, no COMT-specific fluorescence of plasma membranes was detected. The signal in the endoplasmic reticulum was also evident in the cells expressing both recombinant COMT forms. Intracellular native COMT reaction was detected by immunoelectron microscopy in rat C6 glioma cells and an intense cytoplasmic signal was seen in the primary neurons infected with the recombinant Semliki Forest virus. The cells expressing recombinant soluble COMT revealed intense nuclear staining together with diffuse cytoplasmic immunoreactivity, suggesting that a part of soluble COMT is transported to nuclei. Western blotting from rat liver and brain revealed soluble COMT in the nuclei. Enzyme activity measurements from liver cytoplasmic and nuclear fractions suggested that about 5% of the soluble COMT resided in nuclei. The intracellular localization of both COMT forms implies that COMT acts in the cytoplasm and possibly also in the nuclear compartment, and that the physiological substrates of COMT enzymes may have to be internalized before their methylation by COMT.

Characterization of the rat catechol-O-methyltransferase gene proximal promoter: identification of a nuclear protein-DNA interaction that contributes to the tissue-specific regulation

The methylating enzyme catechol-O-methyltransferase (COMT) is an important inactivator of substrates containing catechol-structure, such as catechol neurotransmitters and hormones. In previous studies, the rat COMT gene has been cloned and characterized, and it has been shown that the two COMT polypeptides, S- and MB-COMT, are expressed from one gene by cooperation of two separate promoters. One promoter, P2, functions constitutively, whereas the other, the proximal P1 promoter, is regulated in a tissue-specific manner. In this report, a more detailed analysis of the rat P1 promoter is presented. By using reporter gene constructs, it is shown that upstream sequences of the P1 promoter contain several regions that modulate the expression either positively or negatively. These experiments also show that the region between the MB- and S-ATG translation initiation codons is indispensable for the activity of this promoter. Analysis of this region by DNase I footprinting and gel retardation assays identified the presence of several DNA elements with SP1 and NF1 recognition site homologies that bound both liver and brain nuclear proteins. However, one 11-nucleotide-long DNA region containing an overlapping consensus binding sequence for CREB and C/EBP-like factors reacted only with the liver nuclear lysate. Supershift experiments suggest that the transcription factor C/EBPalpha mediates the tissue-specific expression of the rat COMT P1 promoter.

Genomic organization of the human catechol O-methyltransferase gene and its expression from two distinct promoters

Human genomic DNA fragments containing catechol O-methyltransferase (COMT) sequences were isolated and the exon-intron structure analysed by sequencing, PCR and comparing to the human COMT cDNA sequences. The gene contains six exons, of which exons 1 and 2 are noncoding. MB-ATG and S-ATG codons, responsible for the initiation of translation of the membrane-bound (MB) and soluble (S) forms of the enzyme, are located in exon 3. Two distinct COMT-specific transcripts, 1.3 kb and 1.5 kb, were detected in various human tissues and cell lines. Different quantities of the shorter COMT-specific mRNA in the tissues studied suggest a tissue-specific regulation of the COMT gene at transcriptional level. Mapping of the 5' ends of the COMT mRNAs showed that transcription initiates at multiple sites in two separate DNA regions, which are preceded by functional promoter sequences. The proximal promoter (P1), located between the two translation initiation codons and extending approximately 200 bp upstream of the MB-ATG initiation codon, apparently gives rise to the 1.3-kb S-COMT mRNA (S-mRNA). The distal promoter (P2) is located in a DNA fragment in front of and partly overlapping the transcription-start region of the 1.5-kb transcript, suggesting that it controls the expression of this MB-mRNA. Similarities between the rat and human COMT gene promoters are analyzed.

Production of rat soluble and membrane-bound catechol O-methyltransferase forms from bifunctional mRNAs

In the rat, the catechol O-methyltransferase (COMT) gene has been found to contain two promoters, P1 and P2. This organization enables the gene to produce a soluble (S-COMT) and a membrane-associated (MB-COMT) protein by using two in-frame ATG initiation codons (S- and MB-ATG). The P1 promoter expresses a 1.6 kb transcript (S-mRNA) which codes for the S-COMT polypeptide only. Here we demonstrate that the P2 promoter controls the expression of alternatively spliced 1.9 kb transcripts (MB-mRNA) which differ by a 27-nucleotide region immediately upstream of the MB-AUG codon. The presence of the 27-base sequence alters the nucleotide at position -3 from G to C, thereby changing the translation initiation context of the MB-AUG codon. Expression experiments in COS-7 cells using full-length COMT cDNAs showed that this alteration affected the initiation of the translation of the MB-AUG and consequently changed the relative amounts of MB- and S-COMT polypeptides produced. No proteolytic cleavage of the MB-COMT form to S-COMT was detected in in vitro or in vivo pulse-chase experiments. We conclude that the bifunctional 1.9 kb mRNAs are able to produce both S-COMT and MB-COMT polypeptide by the leaky scanning mechanism of translation initiation.

Structure of the rat catechol-O-methyltransferase gene: separate promoters are used to produce mRNAs for soluble and membrane-bound forms of the enzyme

The enzyme catechol-O-methyltransferase (COMT) catalyzes the inactivation of catechol-containing molecules by methylation. The cDNAs for the rat and human COMT have recently been cloned and recombinant proteins expressed in prokaryotic and eukaryotic cells. We describe here the structure of the rat COMT gene and its 5'-flanking sequences. The gene spans at least 13 kb and is composed of 5 exons, the first one noncoding. The two ATG codons for the initiation of translation of the membrane-bound (MB-COMT) and soluble (S-COMT) forms of the enzyme reside in the second exon. The gene expresses two mRNA species of 1.6 kb and 1.9 kb that have different tissue distributions. The expression of the transcripts is regulated by at least two promoters, P1 and P2. The P1 promoter expresses the shorter transcript in a tissue-specific manner and is located between the ATG codons in the coding region of the longer transcript. The P2 promoter is constitutive and responsible for the expression of the longer transcript. The shorter 1.6-kb mRNA (S-mRNA) produces only the S-COMT polypeptide, whereas the longer 1.9-kb mRNA (MB-mRNA) is able to direct synthesis of both forms of the COMT enzyme.

Increased steroid hormone secretion in mouse Leydig tumor cells after induction of cholesterol translocation by sphingomyelin degradation

The effects of sphingomyelin degradation on [3H]cholesterol transfer from the cell surface to mitochondria were examined in mouse Leydig tumor cells. These cells were used since they utilize cholesterol for steroid hormone synthesis in the mitochondria, and also possess acyl-CoA: cholesterol acyl transferase (ACAT) activity in the endoplasmic reticulum. Exposure of glutaraldehyde-fixed mouse Leydig tumor cells to sphingomyelinase (50 mU/ml, 60 min) resulted in the degradation of about 50% of cell sphingomyelin, suggesting that only half of the sphingomyelin mass in these cells was located in the exoleaflet of the plasma membrane. The partial sphingomyelin degradation resulted in the translocation of cellular unesterified [3H]cholesterol from plasma membranes (cholesterol oxidase-susceptible) to intracellular compartments (oxidase-resistant). The fraction of [3H]cholesterol that was translocated, i.e., between 20 and 50%, varied with different [3H]cholesterol-labeling methods. Cholesterol translocation induced by sphingomyelin degradation subsequently led to the stimulation of ACAT activity, suggesting that a fraction of cell surface cholesterol was transported to the endoplasmic reticulum. The sphingomyelinase-induced [3H]cholesterol flow from the cell surface to the cell interior was also in part directed to the mitochondria, as evidenced by the increased secretion of [3H]steroid hormones. In addition, the cyclic AMP-induced activation of steroidogenesis was further enhanced by the sphingomyelinase-induced cholesterol translocation. Based on the current results, it seems evident that a significant portion of the translocated [3H]cholesterol made its way from plasma membranes into the mitochondria for steroidogenesis.

A solution hybridization method for quantification of mRNAs: determining the amount and stability of oncogene mRNA

A solution hybridization method for the quantification of specific mRNAs is described. This assay utilizes complementary RNA probes prepared by in vitro transcription, sandwich hybridization in solution, and affinity-based hybrid collection. The possibility of using this method for crude biological samples without purifying mRNAs makes it ideal when accurate quantification of multiple samples is needed. Human N-myc oncogene transcript was used as a model and as little as 0.24 pg (2 X 10(5) molecules) of N-myc mRNA could be detected. Using this assay it was shown that human neuroblastoma IMR-32 cells contain approximately 500 N-myc mRNA molecules per cell having a half-life of approximately 35 min.

Effects of sphingomyelin degradation on cholesterol mobilization and efflux to high-density lipoproteins in cultured fibroblasts

The hydrolysis of sphingomyelin from cellular plasma membranes imposes many consequences on cellular cholesterol homeostasis by causing a rapid and dramatic redistribution of plasma membrane cholesterol within the cells (Slotte, J.P. and Bierman, E.L. (1988) Biochem. J. 250, 653-658). The objective of this study was to examine the effects of an extracellular cholesterol acceptor on the directions of the sphingomyelinase-induced cholesterol flow in cultured fibroblasts. We have used HDL3 as a physiological acceptor for cholesterol, and measured the effects of sphingomyelin hydrolysis on efflux and endogenous esterification of cellular [3H]cholesterol. Treatment of cells with sphingomyelinase did induce a dramatically increased esterification of plasma-membrane-derived [3H]cholesterol. The presence of HDL3 in the medium (100 micrograms/ml) did not prevent or reduce the extent of the sphingomyelinase-induced cellular esterification of [3H]cholesterol. Degradation of cellular sphingomyelin (75% hydrolysis) also did not enhance the rate of [3H]cholesterol efflux from the plasma membranes to HDL3. In addition, we also observed that the degradation of sphingomyelin in the HDL3 particles (complete degradation) did not change the apparent rate of [3H]cholesterol transfer from HDL3 to the cells. These findings together indicate that hydrolysis of sphingomyelin did not markedly affect the rates of cholesterol surface transfer between HDL3 and cells. By whatever mechanism cholesterol is forced to be translocated from the plasma membranes subsequent to the degradation of sphingomyelin, it appears that the sterol flow is specifically directed towards the interior of the cells.

Hydrolysis of single-stranded RNA in aqueous solutions--effect on quantitative hybridizations

Single stranded RNA is non-enzymatically hydrolysed in aqueous solutions at neutral pH at elevated temperatures. This hydrolysis causes practical problems in different hybridization procedures. Synthetic cRNA transcribed from the human p53 oncogene was found to be partially destroyed after 6 hours and completely destroyed after overnight incubation at 60 degrees C. At lower temperatures the cRNA was preserved intact in spite of overnight incubation, but at higher temperatures (80 degrees C) the degradation occurred in less than 2 hours. The effect of the hydrolysis on hybridization results was studied by measuring in solution the hybridization kinetics of the cRNAs of another human oncogene, N-myc. It is obvious that conditions generally used for DNA hybridizations cannot be utilized for RNA in quantitative studies.

Quantification of polymerase chain reaction products by affinity-based hybrid collection

We have used oligonucleotides modified with biotin in the 5'-end as primers in the polymerase chain reaction (PCR)-amplification. This results in the synthesis of 5'-biotinylated DNA molecules, which are detected by hybridization to a labelled probe in solution. The formed hybrids are collected on an avidin-matrix by mediation of the biotin residue of the target molecules. The affinity-based hybrid collection method is quantitative and makes it possible to measure the amount of DNA produced in the PCR-amplification. At low concentrations of template the efficiency of the process is close to 100%, making it possible to detect the presence of a few molecules of target DNA in 25 cycles. With high template concentrations the efficiency of the process is low.

Screening of premalignant cervical lesions for HPV 16 DNA by sandwich and in situ hybridization techniques

A series of 97 cervical smears and 69 directed punch biopsies derived from 84 consecutive women prospectively followed-up for cervical HPV (human papillomavirus) infections were studied using the sandwich hybridization and in situ hybridization techniques with HPV 16 DNA probes. The aim was to test the sensitivity and applicability of these two techniques in routine diagnosis of cervical HPV infections from smears. As a measure of specimen adequacy, the number of cells recovered in the cervical scrape was determined along with HPV 16 DNA in the sandwich hybridization test using human pro-alpha 2(I)-collagen gene probe. CIN (cervical intraepithelial neoplasia) was suggested in 56% of the patients by the Pap smear, and disclosed in 65% of the biopsies. HPV 16 DNA was present in 57% of cervical scrapes consistent with CIN, i.e., were of Pap smear classes III or IV. Forty percent of the scrapes not suggestive of CIN, i.e., Pap smear classes I or II, also contained HPV 16 DNA. The detection rate for HPV 16 DNA of the sandwich hybridization method was 89% of that of the in situ method in adequate scrapes, but only 43% in cell-poor specimens. The number of HPV 16 DNA-positive scrapes as compared with the total number of diagnoses obtained by studying also the biopsies was 31/36 (69 patients). The results indicate that the cervical scrape as a noninvasive specimen is applicable for screening of cervical HPV infections, and it can be studied with acceptable sensitivity by the rapid sandwich hybridization technique. However, if a punch biopsy is indicated it should be studied using the in situ hybridization technique that allows more sensitive detection of HPV DNA than any other hybridization method and enables the analysis of several HPV types in the same sample instead of only one HPV type in the scrapes.

Analysis of P fimbriae on Escherichia coli O2, O4, and O6 strains by immunoprecipitation

P fimbriae on Escherichia coli O2, O4, and O6 strains were analyzed by immunoprecipitation. Fimbrial extracts were prepared from a total of 35 strains and tested for precipitation with four anti-P-fimbria sera. The overall fimbrial composition of the strains was related to the O:K:H serotype, and two to three P fimbrial variants per strain were found on most of the O4 and some of the O6 strains. The O2 strains, in contrast, showed only one antigenic variant of P fimbriae per strain, which was serologically unrelated to those of the O4 and O6 strains. The results stress the multiplicity and serological complexity of E. coli P fimbriae.

Fimbriation and P-antigen recognition of Escherichia coli strains harbouring mutated recombinant plasmids encoding fimbrial adhesins of the uropathogenic E. coli strain KS71

Deletion mutants of recombinant plasmids encoding the KS71B fimbrial antigens of the uropathogenic Escherichia coli strain KS71 (O4:K12) were constructed. The effects of these mutations were tested by transforming the mutated plasmids into non-fimbriated E. coli HB101 cells and testing the transformants for fimbriation and haemagglutination. A deletion transcriptionally upstream from the fimbrial subunit gene increased the expression of KS71B fimbriae. Deletion of the fimbrial subunit gene resulted in non-fimbriated but haemagglutinating transformants, whereas a deletion 6 kb transcriptionally downstream from the subunit gene resulted in non-haemagglutinating but fimbriate transformants, indicating that fimbriation and haemagglutination were genetically separable. We also present evidence suggesting that the fimbrillin and haemagglutinin are physically associated in the wild-type KS71 strain.