Delayed Drowsiness After Normobaric Hypoxia Training in an F/A-18 Hornet Simulator

BACKGROUND: In military aviation, due to high-altitude flight operations, hypoxia training is mandatory and nowadays is mainly done as normobaric hypoxia training in flight simulators. During the last decade, scientific data has been published about delayed recovery after normobaric hypoxia, known as a "hypoxia hangover." Sopite syndrome is a symptom complex that develops as a result of exposure to real or apparent motion, and it is characterized by yawning, excessive drowsiness, lassitude, lethargy, mild depression, and a reduced ability to focus on an assigned task.CASE REPORT: In this study, we present the case of a 49-yr-old pilot who participated in normobaric hypoxia refreshment training in an F/A-18C Hornet simulator and experienced delayed drowsiness, even 3 h after the training.DISCUSSION: This case report demonstrates the danger of deep hypoxia. Hypoxia training instructions should include restrictions related to driving a car immediately after hypoxia training. In addition, hypoxia may lower the brain threshold for sopite syndrome.Varis N, Leinonen A, Perälä J, Leino TK, Husa L, Sovelius R. Delayed drowsiness after normobaric hypoxia training in an F/A-18 Hornet simulator. Aerosp Med Hum Perform. 2023; 94(9):715-718.

Hyperventilation and Hypoxia Hangover During Normobaric Hypoxia Training in Hawk Simulator

Introduction: In military aviation during high-altitude operations, an oxygen or cabin pressure emergency can impair brain function and performance. There are variations in individuals’ physiological responses to low partial pressure of oxygen and hypoxia symptoms can vary from one exposure to another. The aim of this study was to evaluate how normobaric hypoxia (NH) affects pilots’ minute ventilation and 10 min afterwards on Instrument Landing System (ILS) flight performance in Hawk simulator during a tactical flight sortie.

Methods: Fifteen volunteer fighter pilots from the Finnish Air Force participated in this double blinded, placebo controlled and randomized study. The subjects performed three flights in a tactical Hawk simulator in a randomized order with full flight gear, regulators and masks on. In the middle of the flight without the subjects’ knowledge, 21% (control), 8% or 6% oxygen in nitrogen was turned on. Minute ventilation (VE) was measured before, during NH and after NH. Forehead peripheral oxygen saturation (SpO₂), wireless ECG and subjective symptoms were documented. The flights were conducted so that both subjects and flight instructors were blinded to the gas mixture. The pilots performed tactical maneuvers at simulated altitude of 20,000 ft or 26,000 ft until they recognized the symptoms of hypoxia. Thereafter they performed hypoxia emergency procedures with 100% oxygen and returned to base (RTB). During the ILS approach, flight performance was evaluated.

Results: The mean VE increased during NH from 12.9 L/min (21% O2 on the control flight) to 17.8 L/min with 8% oxygen (p < 0.01), and to 21.0 L/min with 6% oxygen (p < 0.01). Ten minutes after combined hyperventilation and hypoxia, the ILS flight performance decreased from 4.4 (control flight) to 4.0 with 8% oxygen (p = 0.16) and to 3.2 with 6% oxygen (p < 0.01). A significant correlation (r = -0.472) was found between the subjects’ VE during 6% oxygen exposure and the ILS flight performance.

Discussion: Hyperventilation during NH has a long-lasting and dose-dependent effect on the pilot’s ILS flight performance, even though the hypoxia emergency procedures are executed 10 min earlier. Hyperventilation leads to body loss of carbon dioxide and hypocapnia which may even worsen the hypoxia hangover.

Normobaric hypoxia training in military aviation and subsequent hypoxia symptom recognition

Altitude hypoxia episodes are increasingly common in military aviation. Hypoxia training is mandatory for fighter pilots, but evidence-based data on the effects of training are scarce. The purpose of this study was to validate the normobaric hypoxia (NH) training effect. Data were collected from 89 pilots from the Finnish Air Force (FINAF). This survey was conducted in a tactical F/A-18C Hornet simulator in two sessions under normobaric conditions, in which the pilots performed flight missions and breathed 21% oxygen (O₂) in nitrogen (N₂), and blinded to the pilot, the breathing gas was changed to a hypoxic mixture containing either 8, 7 or 6% O₂ in N₂. The time taken to notice hypoxia symptoms and peripheral capillary O₂ saturation was measured. A mean of 2.4 years after the initial training, pilots recognised their hypoxic symptoms 18 s quicker with 8% O₂ mixture, 20 s quicker with 7% O₂ and 10 s quicker with 6% O₂. Our data indicate that NH training in a flight simulator helps pilots to recognise hypoxia symptoms earlier, and may, thus, enhance flight safety.Practitioner Summary: We show that hypoxia training enhances pilots' ability to recognise symptoms of acute normobaric hypoxic exposure up to 2.4 years after an initial NH training session. Based on these data, refreshment NH training is nowadays mandatory every 3 years in the FINAF as opposed to the North Atlantic Treaty Organisation (NATO) Standardisation Agreement (STANAG) requirement of 5-year intervals between hypoxia trainings.Abbreviations: O₂: oxygen; TUC; time of usefull consciousness; SpO₂: peripheral capillary oxygen saturation; NATO: North Atlantic Treaty Organization; STANAG: stanrdization agreement; HH: hypobaric hypoxia; NH: normobaric hypoxia; FINAF: finnish air force; N₂: nitrogen; ECG: electrocardiogram; CI: confidence interval; SD: standard deviation.

Emphysematous Pyelonephritis

Six patients (all women, mean age 59.8 years) with emphysematous pyelonephritis, a rare, severe inflammation causing renal parenchymal destruction and affecting diabetics more commonly than non-diabetics, are described. Four of the patients were diabetics. All underwent ultrasound examination (US), and five computed tomography (CT) of the kidneys. CT was the most reliable diagnostic method. Differentiation between gas and calcification was difficult at US in three patients. Conventional tomography was performed in two patients and showed intra-renal gas. All six patients recovered; three patients had nephrectomy, one as an emergency procedure and two as an elective procedure after two weeks of antibiotic treatment. Infection was eradicated in the other three patients by percutaneous drainage, electrolyte correction and antibiotics. It was concluded that while conventional abdominal radiography may permit the diagnosis of emphysematous pyelonephritis by demonstrating intra-renal gas, CT is the most reliable diagnostic examination. Emergency nephrectomy may not be necessary in all cases.

Radiographic Diagnosis of Bile Duct Cysts

Twelve patients and a foetus with congenital bile duct cysts suggested in the majority of cases at routine upper abdominal sonography were examined by two or more of the following investigations: ultrasonorgaphy (10 patients), computed tomography (5 patients), CT-cholangiography (2 patients), oral cholecystography (7 patients), intravenous cholangiography (4 patients), endoscopic retrograde cholangiopancreatography (ERCP) (6 patients) and cholescintigraphy (2 patients). The sensitivity of each investigation for the diagnosis of bile duct cysts was: ultrasound 40 per cent, computed tomography 20 per cent, CT-cholangiography 100 per cent, oral cholecystography 17 per cent, intravenous cholangiography 75 per cent, ERCP 83 per cent and cholescintigraphy 50 per cent. When a bile duct cyst has been suggested by ultrasonography or other examinations, without a conclusive diagnosis being made, CT-cholangiography is recommended as the next examination. In patients with impaired biliary excretion of contrast medium, ERCP may be required to achieve the diagnosis.

What Data to Use for Forest Conservation Planning? A Comparison of Coarse Open and Detailed Proprietary Forest Inventory Data in Finland

The boreal region is facing intensifying resource extraction pressure, but the lack of comprehensive biodiversity data makes operative forest conservation planning difficult. Many countries have implemented forest inventory schemes and are making extensive and up-to-date forest databases increasingly available. Some of the more detailed inventory databases, however, remain proprietary and unavailable for conservation planning. Here, we investigate how well different open and proprietary forest inventory data sets suit the purpose of conservation prioritization in Finland. We also explore how much priorities are affected by using the less accurate but open data. First, we construct a set of indices for forest conservation value based on quantitative information commonly found in forest inventories. These include the maturity of the trees, tree species composition, and site fertility. Secondly, using these data and accounting for connectivity between forest types, we investigate the patterns in conservation priority. For prioritization, we use Zonation, a method and software for spatial conservation prioritization. We then validate the prioritizations by comparing them to known areas of high conservation value. We show that the overall priority patterns are relatively consistent across different data sources and analysis options. However, the coarse data cannot be used to accurately identify the high-priority areas as it misses much of the fine-scale variation in forest structures. We conclude that, while inventory data collected for forestry purposes may be useful for forest conservation purposes, it needs to be detailed enough to be able to account for more fine-scaled features of high conservation value. These results underline the importance of making detailed inventory data publicly available. Finally, we discuss how the prioritization methodology we used could be integrated into operative forest management, especially in countries in the boreal zone.

Characterization of microbial contaminants in urine

Modern, molecular microbiological methods were applied to urine samples from control subjects and athletes for characterization of the microbial community. High abundance of lactobacilli, enterococci, and enterobacteria was detected in urine samples, suggesting that gastrointestinal and urogenital tracts act as contamination sources. Athlete samples, but not control samples, showed an abundance of pseudomonads, a bacterial group reported to metabolize steroids. Overall, the bacteria detected are known to be capable of altering steroid profiles, emphasizing the importance of good hygiene at sampling in reliable doping control.

Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison

Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in human urine after dosing of the most widely abused AAS in sports, e.g. methandienone, methenolone, methyltestosterone, nandrolone and testosterone, and certain deuterium-labeled analogs of these metabolites. Sample preparation and the LC-ESI-MS/MS method were optimized, validated, and the overall process was implemented and the results between seven laboratories were compared. All the metabolites were extracted simultaneously by solid-phase extraction (SPE) and analyzed by LC-ESI-MS/MS with positive ionization mode and multiple reaction monitoring (MRM). Recovery of the SPE for the AAS glucuronides was 89-100% and ten out of twelve compounds had detection limits in the range of 1-10 ng/ml in urine. The results for inter/intraday repeatability were satisfactory and the interlaboratory comparison with authentic urine samples demonstrated the ease of method transfer from one instrument setup to another. When equivalent triple quadrupole analyzers were employed the overall performance was independent from instrument manufacturer, electrospray ionisation (ESI) or atmospheric pressure chemical ionization (APCI) and liquid chromatohraphic (LC) column, whereas major differences were encountered when changing from one analyzer type to another, especially in the analysis of those AAS glucuronides ionized mainly as adducts.

Insulins in equine urine: qualitative analysis by immunoaffinity purification and liquid chromatography/tandem mass spectrometry for doping control purposes in horse-racing

Insulin is a peptide hormone consisting of two peptide chains (A- and B-chain) that are cross-linked by two disulfide bonds. To obtain improved pharmacokinetic onset of action profiles of insulin treatment in diabetic patients, recombinant long-, intermediate-, and rapid-acting insulin analogs are produced, in which the C-terminal end of the B-chain plays an especially important role.A review of the veterinary literature reveals the low prevalence of equine type I diabetes mellitus, which indicates that the therapeutic use of insulin in racing horses is unlikely. Although there is no unequivocal evidence of an overall performance-enhancing effect of insulin, in human sports the misuse of insulin preparations is reported among elite athletes. The desired effects of insulin include the increase of muscular glycogen prior to sports event or during the recovery phase, in addition to a chalonic action, which increases the muscle size by inhibiting protein breakdown. In the present study urinary insulin was detected in equine samples and differences between equine insulin, human insulin, as well as rapidly acting recombinant insulin variants were examined. The method was based on sample purification by solid-phase extraction (SPE) and immunoaffinity chromatography (IAC), and subsequent analysis by microbore liquid chromatography (LC) and tandem mass spectrometry (MS/MS) using top-down sequencing for the determination of various insulins. Product ion scan experiments of intact proteins and B-chains enabled the differentiation between endogenously produced equine insulin, its DesB30 metabolite, human insulin and recombinant insulin analogs, and the assay allowed the assignment of individual product ions, especially those originating from modified C-termini of B-chains.

Diurnal blood glucose profiles in women with gestational diabetes with or without hypertension

AIM

The aim of the study was to establish whether diurnal blood glucose profiles differed in women with gestational diabetes (GDM) with different forms of hypertensive complications.

METHODS

The subjects were patients diagnosed at 26-32 gestational weeks as having GDM (n = 178). They were classified as being normotensive, having chronic hypertension (with or without superimposed pre-eclampsia on chronic hypertension) or pregnancy-induced hypertension (with or without proteinuria). We compared diurnal blood glucose profiles (blood glucose taken every 4 h over 24 h) in these three groups.

RESULTS

Hypertension complicated 43% of the women with GDM. The glucose profiles were similar between the three groups, except that in early morning hours (from 04:00 to 08:00 h) blood glucose concentrations increased in mothers with chronic hypertension, whereas they decreased in the normotensive women. In univariate regression analysis, both obesity (BMI > or = 28 kg/m(2)) and chronic hypertension showed significant association with blood glucose rise from 04:00 to 08:00 h, but in a multiple regression model neither showed significant independent effect.

CONCLUSIONS

The rise in blood glucose levels during the early morning hours in women with GDM and chronic hypertension could reflect greater insulin resistance and sympathetic overactivity.

Effect of changes in body posture on vasoactive hormones in pre-eclamptic women

The aim of this study was to determine the normality or otherwise of neurohormone indices, particularly the sympathetic nervous system, in pre-eclamptic patients and document whether changes in body posture magnify any differences between pre-eclamptic and normal women. We studied 11 women with pre-eclampsia and compared them with 17 matched normotensive pregnant women and eight nonpregnant women. Measurements of arterial pressure, heart rate and neurohormones were carried out with subjects in the left lateral position, then supine, left lateral, with upright posture and finally with assumption of the left lateral position again. Main outcome measures were arterial pressure, heart rate and hormones (plasma norepinephrine, renin activity, natriuretic peptides and endothelin-1). We observed that plasma norepinephrine levels were higher in pre-eclamptic than normotensive pregnant women and this was most obvious in the upright position. Plasma renin activity was likewise higher in pre-eclamptic than normotensive pregnant women, again most obvious with upright posture. Plasma natriuretic peptides and endothelin-1 levels were similar in pre-eclamptics and normotensive pregnant women. These data strengthen the premise that pre-eclampsia is associated with sympathetic overactivity as reflected by plasma norepinephrine levels, most obviously observed in the upright position.

Screening of free 17-alkyl-substituted anabolic steroids in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry

A qualitative liquid chromatography-electrospray ionization tandem mass spectrometry method was developed for screening of the abuse of 4-chlorodehydromethyltestosterone, danazol, fluoxymesterone, formebolone, metandienone, oxandrolone, and stanozolol. The introduced method measures simultaneously nine different 17-alkyl-substituted anabolic androgenic steroids or their unconjugated metabolites in human urine, using methyltestosterone as an internal standard. Sample preparation involved one-step liquid extraction. Liquid chromatographic separation was achieved on a reversed-phase column with methanol-water gradient containing 5 mmol/l ammonium acetate and 0.01% (v/v) acetic acid. Compounds were ionized in the positive mode and detected by multiple reaction monitoring. All steroids within the study could be selectively detected in urine with detection limits of 0.1-2.0 ng/ml. The method showed good linearity up to 250 ng/ml with correlation coefficients higher than 0.9947. With simple and fast sample preparation, low limits of detection, and high selectivity and precision, the developed method provides advantages over the present testing methods and has the potential for routine qualitative screening method of unconjugated 17-alkyl-substituted anabolic steroids in human urine.

Feasibility of a liquid-phase microextraction sample clean-up and liquid chromatographic/mass spectrometric screening method for selected anabolic steroid glucuronides in biological samples

Anabolic androgenic steroids (AAS) are metabolized extensively in the human body, resulting mainly in the formation of glucuronide conjugates. Current detection methods for AAS are based on gas chromatographic/mass spectrometric (GC/MS) analysis of the hydrolyzed steroid aglycones. These analyses require laborious sample preparation steps and are therefore time consuming. Our interest was to develop a rapid and straightforward method for intact steroid glucuronides in biological samples, using liquid-phase microextraction (LPME) sample clean-up and concentration method combined with liquid chromatographic/tandem mass spectrometric (LC/MS/MS) analysis. The applicability of LPME was optimized for 13 steroid glucuronides, and compared with conventional liquid-liquid extraction (LLE) and solid-phase extraction (SPE) procedures. An LC/MS/MS method was developed for the quantitative detection of AAS glucuronides, using a deuterium-labeled steroid glucuronide as the internal standard. LPME, owing to its high specificity, was shown to be better suited than conventional LLE and SPE for the clean-up of urinary AAS glucuronides. The LPME/LC/MS/MS method was fast and reliable, offering acceptable reproducibility and linearity with detection limits in the range 2-20 ng ml(-1) for most of the selected AAS glucuronides. The method was successfully applied to in vitro metabolic studies, and also tested with an authentic forensic urine sample. For a urine matrix the method still has some unsolved problems with specificity, which should be overcome before the method can be reliably used for doping analysis, but still offering additional and complementary data for current GC/MS analyses.

Liquid chromatography/mass spectrometry in anabolic steroid analysis--optimization and comparison of three ionization techniques: electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization

The applicability of liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the detection of the free anabolic steroid fraction in human urine was examined. Electrospray ionization (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization methods were optimized regarding eluent composition, ion source parameters and fragmentation. The methods were compared with respect to specificity and detection limit. Although all methods proved suitable, LC/ESI-MS/MS with a methanol-water gradient including 5 mM ammonium acetate and 0.01% acetic acid was found best for the purpose. Multiple reaction monitoring allowed the determination of steroids in urine at low nanogram per milliliter levels. LC/MS/MS exhibited high sensitivity and specificity for the detection of free steroids and may be a suitable technique for screening for the abuse of anabolic steroids in sports.

Hydrophobic amino acid residues are critical for the immunodominant epitope of the Goodpasture autoantigen. A molecular basis for the cryptic nature of the epitope

Goodpasture (GP) autoimmune disease is caused by autoantibodies to type IV collagen that bind to the glomerular basement membrane, causing rapidly progressing glomerulonephritis. The immunodominant GP(A) autoepitope is encompassed by residues 17-31 (the E(A) region) within the noncollagenous (NC1) domain of the alpha 3(IV) chain. The GP epitope is cryptic in the NC1 hexamer complex that occurs in the type IV collagen network found in tissues and inaccessible to autoantibodies unless the hexamer dissociates. In contrast, the epitope for the Mab3 monoclonal antibody is also located within the E(A) region, but is fully accessible in the hexamer complex. In this study, the identity of residues that compose the GP(A) autoepitope was determined, and the molecular basis of its cryptic nature was explored. This was achieved using site-directed mutagenesis to exchange the alpha3(IV) residues in the E(A) region with the corresponding residues of the homologous but non-immunoreactive alpha1(IV) NC1 domain and then comparing the reactivity of the mutated chimeras with GP(A) and Mab3 antibodies. It was shown that three hydrophobic residues (Ala(18), Ile(19), and Val(27)) and Pro(28) are critical for the GP(A) autoepitope, whereas two hydrophilic residues (Ser(21) and Ser(31)) along with Pro(28) are critical for the Mab3 epitope. These results suggest that the cryptic nature of the GP(A) autoepitope is the result of quaternary interactions of the alpha 3, alpha 4, and alpha 5 NC1 domains of the hexamer complex that bury the one or more hydrophobic residues. These findings provide critical information for understanding the etiology and pathogenesis of the disease as well as for designing drugs that would mimic the epitope and thus block the binding of GP autoantibodies to autoantigen.

Autosomal dominant Alport syndrome caused by a COL4A3 splice site mutation

BACKGROUND

Alport syndrome (AS) is a clinically and genetically heterogeneous renal disorder, predominantly affecting the type IV collagen alpha 3/alpha 4/alpha 5 network of the glomerular basement membrane (GBM). AS can be caused by mutations in any of the three genes encoding these type IV collagen chains. The majority of AS families (85%) are X-linked (XL-AS) involving mutations in the COL4A5 gene. Mutations in the COL4A3 and COL4A4 genes cause autosomal recessive AS (AR-AS), accounting for approximately 14% of the cases. Recently, autosomal dominant AS (AD-AS) was linked to the COL4A3/COL4A4 locus in a large family.

METHODS

COL4A3 and COL4A4 cDNAs were generated by nested reverse transcription-polymerase chain reaction and were analyzed by DNA sequence analysis. Denaturating high-performance liquid chromatography (DHPLC) was used for mutation and segregation analysis at the genomic DNA level.

RESULTS

In the AD-AS family, a splice site mutation resulting in skipping of exon 21 of the COL4A3 gene was detected. The mutation does not alter the reading frame and is predicted to result in a COL4A3 chain with an internal deletion.

CONCLUSION

As the NC domain is intact, this chain may be incorporated and distort the collagen triple helix, thereby causing the dominant effect of the mutation. The finding of a specific COL4A3 mutation in AD-AS completes the spectrum of type IV collagen mutations in all genetic forms of AS.

Electrospray and atmospheric pressure chemical ionization tandem mass spectrometric behavior of eight anabolic steroid glucuronides

Mass spectrometric and tandem mass spectrometric behavior of eight anabolic steroid glucuronides were examined using electrospray (ESI) and atmospheric pressure chemical ionization (APCI) in negative and positive ion mode. The objective was to elucidate the most suitable ionization method to produce intense structure specific product ions and to examine the possibilities of distinguishing between isomeric steroid glucuronides. The analytes were glucuronide conjugates of testosterone (TG), epitestosterone (ETG), nandrolone (NG), androsterone (AG), 5alpha-estran-3alpha-ol-17-one (5alpha-NG), 5beta-estran-3alpha-ol-17-one (5beta-NG), 17alpha-methyl-5alpha-androstane-3alpha,17beta-diol (5alpha-MTG), and 17alpha-methyl-5beta-androstane-3alpha,17beta-diol (5beta-MTG), the last four being new compounds synthesized with enzyme-assisted method in our laboratory. High proton affinity of the 4-ene-3-one system in the steroid structure favored the formation of protonated molecule [M + H]+ in positive ion mode mass spectrometry (MS), whereas the steroid glucuronides with lower proton affinities were detected mainly as ammonium adducts [M + NH4]+. The only ion produced in negative ion mode mass spectrometry was a very intense and stable deprotonated molecule [M - H]- . Positive ion ESI and APCI MS/MS spectra showed abundant and structure specific product ions [M + H - Glu]+, [M + H - Glu - H2O]+, and [M + H - Glu - 2H2O]+ of protonated molecules and corresponding ions of the ammonium adduct ions. The ratio of the relative abundances of these ions and the stability of the precursor ion provided distinction of 5alpha-NG and 5beta-NG isomers and TG and ETG isomers. Corresponding diagnostic ions were only minor peaks in negative ion MS/MS spectra. It was shown that positive ion ESI MS/MS is the most promising method for further development of LC-MS methods for anabolic steroid glucuronides.

The goodpasture autoantigen. Identification of multiple cryptic epitopes on the NC1 domain of the alpha3(IV) collagen chain

Goodpasture (GP) disease is an autoimmune disorder in which autoantibodies against the alpha3(IV) chain of type IV collagen bind to the glomerular and alveolar basement membranes, causing progressive glomerulonephritis and pulmonary hemorrhage. Two major conformational epitope regions have been identified on the noncollagenous domain of type IV collagen (NC1 domain) of the alpha3(IV) chain as residues 17-31 (E(A)) and 127-141 (E(B)) (Netzer, K.-O. et al. (1999) J. Biol. Chem. 274, 11267-11274). To determine whether these regions are two distinct epitopes or form a single epitope, three GP sera were fractionated by affinity chromatography on immobilized NC1 chimeras containing the E(A) and/or the E(B) region. Four subpopulations of GP antibodies with distinct epitope specificity for the alpha3(IV)NC1 domain were thus separated and characterized. They were designated GP(A), GP(B), GP(AB), and GP(X), to reflect their reactivity with E(A) only, E(B) only, both regions, and neither, respectively. Hence, regions E(A) and E(B) encompass critical amino acids that constitute three distinct epitopes for GP(A), GP(B), and GP(AB) antibodies, respectively, whereas the epitope for GP(X) antibodies is located in a different unknown region. The GP(A) antibodies were consistently immunodominant, accounting for 60-65% of the total immunoreactivity to alpha3(IV)NC1; thus, they probably play a major role in pathogenesis. Regions E(A) and E(B) are held in close proximity because they jointly form the epitope for Mab3, a monoclonal antibody that competes for binding with GP autoantibodies. All GP epitopes are sequestered in the hexamer configuration of the NC1 domain found in tissues and are inaccessible for antibody binding unless dissociation of the hexamer occurs, suggesting a possible mechanism for etiology of GP disease. GP antibodies have the capacity to extract alpha3(IV)NC1 monomers, but not dimers, from native human glomerular basement membrane hexamers, a property that may be of fundamental importance for the pathogenesis of the disease.

Comparison of sensitivity between gas chromatography-low-resolution mass spectrometry and gas chromatography-high-resolution mass spectrometry for determining metandienone metabolites in urine

In doping control laboratories the misuse of anabolic androgenic steroids is commonly investigated in urine by gas chromatography-low-resolution mass spectrometry with selected ion monitoring (GC-LRMS-SIM). By using high-resolution mass spectrometry (HRMS) detection sensitivity is improved due to reduction of biological background. In our study HRMS and LRMS methods were compared to each other. Two different sets were measured both with HRMS and LRMS. In the first set metandienone (I) metabolites 17alpha-methyl-5beta-androstan-3alpha,17beta-dio l (II), 17-epimetandienone (III), 17beta-methyl-5beta-androst-1-ene-3alpha,17alpha-diol (IV) and 6beta-hydroxymetandienone (V) were spiked in urine extract prepared by solid-phase extraction, hydrolysis with beta-glucuronidase from Escherichia coli and liquid-liquid extraction. In the second set the metabolites were first spiked in blank urine samples of four male persons before pretreatment. Concentration range of the spiked metabolites was 0.1-10 ng/ml in both sets. With HRMS (resolution of 5000) detection limits were 2-10 times lower than with LRMS. However, also with the HRMS method the biological background hampered detection and compounds from matrix were coeluted with some metabolites. For this reason the S/N values of the metabolites spiked had to be first compared to S/N values of coeluted matrix compounds to get any idea of detection limits. At trace concentrations selective isolation procedures should be implemented in order to confirm a positive result. The results suggest that metandienone misuse can be detected by HRMS for a prolonged period after stopping the intake of metandienone.

The goodpasture autoantigen. Mapping the major conformational epitope(s) of alpha3(IV) collagen to residues 17-31 and 127-141 of the NC1 domain

The Goodpasture (GP) autoantigen has been identified as the alpha3(IV) collagen chain, one of six homologous chains designated alpha1-alpha6 that comprise type IV collagen (Hudson, B. G., Reeders, S. T., and Tryggvason, K. (1993) J. Biol. Chem. 268, 26033-26036). In this study, chimeric proteins were used to map the location of the major conformational, disulfide bond-dependent GP autoepitope(s) that has been previously localized to the noncollagenous (NC1) domain of alpha3(IV) chain. Fourteen alpha1/alpha3 NC1 chimeras were constructed by substituting one or more short sequences of alpha3(IV)NC1 at the corresponding positions in the non-immunoreactive alpha1(IV)NC1 domain and expressed in mammalian cells for proper folding. The interaction between the chimeras and eight GP sera was assessed by both direct and inhibition enzyme-linked immunosorbent assay. Two chimeras, C2 containing residues 17-31 of alpha3(IV)NC1 and C6 containing residues 127-141 of alpha3(IV)NC1, bound autoantibodies, as did combination chimeras containing these regions. The epitope(s) that encompasses these sequences is immunodominant, showing strong reactivity with all GP sera and accounting for 50-90% of the autoantibody reactivity toward alpha3(IV)NC1. The conformational nature of the epitope(s) in the C2 and C6 chimeras was established by reduction of the disulfide bonds and by PEPSCAN analysis of overlapping 12-mer peptides derived from alpha1- and alpha3(IV)NC1 sequences. The amino acid sequences 17-31 and 127-141 in alpha3(IV)NC1 have thus been shown to contain the critical residues of one or two disulfide bond-dependent conformational autoepitopes that bind GP autoantibodies.

Goodpasture antigen: expression of the full-length alpha3(IV) chain of collagen IV and localization of epitopes exclusively to the noncollagenous domain

BACKGROUND

Tissue injury in Goodpasture (GP) syndrome (rapidly progressive glomerular nephritis and pulmonary hemorrhage) is mediated by antibasement membrane antibodies that are targeted to the alpha3(IV) chain of type IV collagen, one of five alpha(IV) chains that occur in the glomerular basement membrane. GP antibodies are known to bind epitopes within the carboxyl terminal noncollagenous domain (NC1) of the alpha3(IV) chain, termed the GP autoantigen. Whether epitopes also exist in the 1400-residue collagenous domain is unknown because studies to date have focused solely on the NC1 domain. A knowledge of GP epitopes is important for the understanding of the etiology and pathogenesis of the disease and for the development of therapeutic strategies.

METHODS

A cDNA construct was prepared for the full-length human alpha3(IV) chain. The construct was stably transfected into human embryonic kidney 293 cells. The purified full-length r-alpha3(IV) chain was characterized by electrophoresis and electron microscopy. The capacity of this chain for binding of GP antibodies from five patients was compared with that of the human r-alpha3(IV)NC1 domain by competitive enzyme-linked immunosorbent assay.

RESULTS

The r-alpha3(IV) chain was secreted from 293 cells as a single polypeptide chain that did not spontaneously undergo assembly into a triple-helical molecule. An analysis of GP-antibody binding to the full-length r-alpha3(IV) chain showed binding exclusively to the globular NC1 domain.

CONCLUSION

The full-length human alpha3(IV) chain possesses the capacity to bind GP autoantibodies. The epitope(s) is found exclusively on the nontriple-helical NC1 domain of the alpha3(IV) chain, indicating the presence of specific immunogenic properties. The alpha3(IV) chain alone does not spontaneously undergo assembly into a triple-helical homotrimeric molecule, suggesting that coassembly with either the alpha4(IV) and/or the alpha5(IV) chain may be required for triple-helix formation.

High mutation detection rate in the COL4A5 collagen gene in suspected Alport syndrome using PCR and direct DNA sequencing

Approximately 85% of patients with Alport syndrome (hereditary nephritis) have been estimated to have mutations in the X chromosomal COL4A5 collagen gene; the remaining cases are autosomal with mutations in the COL4A3 or COL4A4 genes located on chromosome 2. In the present work, the promoter sequence and previously unknown intron sequences flanking exons 2 and 37 of COL4A5 were determined. Furthermore, intron sequences flanking the other 49 exons were expanded from 35 to 190 to facilitate mutation analysis of the gene. Using this information, all 51 exons and the promoter region were PCR-amplified and sequenced from DNA of 50 randomly chosen patients with suspected Alport syndrome. Mutations were found in 41 patients, giving a mutation detection rate of 82%. Retrospective analysis of clinical data revealed that two of the cases might be autosomal. Although it could not be determined whether the remaining seven cases (14%) were autosomal or X chromosome-linked, it is likely that some of them were autosomal. It is concluded that PCR amplification and direct DNA sequencing of the promoter and exons is currently the best procedure to detect mutations in COL4A5 in Alport syndrome.

Electrophysiological evidence for cross-modal plasticity in humans with early- and late-onset blindness

It is commonly believed that sensory deprivation can lead to cross-modal reorganization in an immature but not in a mature brain. The results of the present study suggest, however, that plasticity between sensory modalities is possible even in adults: activity indicating involvement of parietal or occipital brain areas in pitch-change discrimination was found in individuals blinded after childhood. Event-related brain potentials of early blinded (before the age of 2 years), late-blinded (12-28 years of age), and sighted adults were recorded to stimulus sequences consisting of standard tones occasionally replaced by deviant tones. Even when participants were not attending to auditory stimuli, the deviant tones elicited the mismatch negativity (MMN) in each group. There were no significant MMN front-back scalp distribution differences among the groups. However, when participants were detecting deviant stimuli, these stimuli elicited N2 and P3 waves that were posterior in distribution in both groups of blind participants relative to those of the sighted participants. These results suggest that cross-modal reorganization may occur even in the mature human brain.

High doses of alcohol increase urinary testosterone-to-epitestosterone ratio in females

The effect of alcohol (1.2 and 2.0 g/kg) on the urinary testosterone-to-epitestosterone (T/E) ratio was studied by two experiments each conducted with four healthy females and males. The intake of 2.0 g/kg of ethanol within 5 h in the evening significantly increased plasma testosterone concentration and ratio of T/E in urine collected next morning in females. The results suggest that alcohol increases the T/E ratio more in females than in males. The effect of high doses of alcohol on urinary T/E ratio must be kept in mind when doping tests are performed during training periods.

Identification of 17 mutations in ten exons in the COL4A5 collagen gene, but no mutations found in four exons in COL4A6: a study of 250 patients with hematuria and suspected of having Alport syndrome

Conditions for polymerase chain-reaction amplification of ten exon regions (Exons 3, 7, 11 through 13, and 15 through 19) of the collagen COL4A5 gene and four exon regions (Exons 2, and 12 through 14) of the COL4A6 gene were sequenced and established in this study. These Type IV collagen genes contain 51 and 48 exons, respectively. The sequences of these exons were determined in the two genes in 250 male patients with hematuria and suspected Alport syndrome. Seventeen mutations were found in nine of the ten exons studied in the COL4A5 gene in 17 patients, whereas no mutations were identified in COL4A6. One mutation was identical in two patients known to be unrelated. The results indicate that mutations in COL4A5 that leading to renal failure are more frequent than those involved in classic Alport syndrome, and also that mutations in COL4A6 are not likely to cause this disease. Furthermore, mutations in COL4A5 are distributed quite randomly and no "hot spots" were found.

Long-term outcome after renovascular surgery. Comparison between thoracoretroperitoneal/saphenous vein and transabdominal/Dacron prosthesis bypass grafting

The outcomes of 16 patients operated on for renovascular hypertension (RH) are analyzed. Eight had undergone surgery by the thoracoretroperitoneal approach with saphenous vein bypass grafting, and 8 by the transabdominal approach with a Dacron prosthesis. Distinct differences in favour of the former group were found after an average of 6 years of follow-up.

Screening of non-steroidal anti-inflammatory drugs, barbiturates and methyl xanthines in equine urine by gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric (GC-MS) screening procedure for 23 acidic drugs in equine urine is described. With the GC-MS method fifteen anti-inflammatory drugs, five barbiturates and three methyl xanthines can be detected with good sensitivity and selectivity. The method consists of alkaline hydrolysis, extraction with organic solvent using salting-out, clean-up extraction, methylation and screening with GC-MS in selected-ion monitoring mode. The limit of detection is 10 micrograms 1(-1) or lower, for most drugs.

Complete primary structure of the human type IV collagen alpha 4(IV) chain. Comparison with structure and expression of the other alpha (IV) chains

The entire sequence of the human alpha 4(IV) collagen chain was determined from cDNA clones and polymerase chain reaction-amplified DNAs. The complete translation product has 1,690 amino acid residues and the processed alpha 4(IV) chain proper 1,652 residues. There is a 38-residue putative signal peptide, a 1,421-residue collagenous domain starting with a 23-residue noncollagenous sequence, and a 231-residue NC1 domain. The Gly-Xaa-Yaa-repeat sequence of the collagenous domain is interrupted at 26 locations by noncollagenous sequences of 1-12 residues in length. The alpha 4(IV) chain contains 31 cysteine residues of which 18 are conserved in the other type IV collagen alpha chains. The calculated molecular weight of the mature alpha 4(IV) chain is 164,123. Analysis of the primary structure showed that the alpha 4(IV) chain belongs to the alpha 2-like type IV collagen chains together with alpha 2(IV) and alpha 6(IV). Northern analyses with RNA from several human fetal tissues revealed quite similar expression patterns for the alpha 4(IV) and alpha 3(IV) chains, but there were also distinct differences in some tissues. The expression patterns of alpha 5(IV) and alpha 6(IV) differed extensively between each other and they also differed from those of alpha 3(IV) and alpha 4(IV).

Complete primary structure of the human alpha 3(IV) collagen chain. Coexpression of the alpha 3(IV) and alpha 4(IV) collagen chains in human tissues

We report the entire primary structure of the human alpha 3(IV) collagen chain determined from cDNA clones and polymerase chain reaction-amplified DNAs. The deduced amino acid sequence demonstrates that the complete translation product consists of 1670 amino acid residues and the mature alpha 3(IV) chain contains 1642 residues with a corresponding calculated molecular mass of 161,753. The full-length translated polypeptide has a signal peptide of 28 amino acids, a 1410-residue collagenous domain starting with a 14-residue noncollagenous sequence, and a 232-residue NC1 domain. There are 23 noncollagenous interruptions in the Gly-X-Y repeat sequence of the collagenous domain. The major transcription start site of the alpha 3(IV) chain gene was also determined from genomic DNA by primer extension and S1 nuclease protection assays. Northern analysis revealed coexpression of the alpha 3(IV) and alpha 4(IV) chains in tissues where expression was observed such as in kidney, muscle, and lung.

Structure of the human type IV collagen COL4A5 gene

The complete exon size and distribution pattern of the human alpha 5(IV) collagen gene COL4A5 has been determined. Seventeen genomic lambda phage clones, eight of which have been described previously (Zhou, J., Hostikka, S.L., Chow, L.T., and Tryggvason, K. (1991) Genomics 9, 1-9), spanning about 160 kilobases of DNA contained 140 kilobases of the gene itself. The clones covered the entire gene with the exception of exons 2 and 37 and their flanking regions so that the exact gene size could not be determined. The sequences of these two exons were, however, determined from polymerase chain reaction products. The COL4A5 gene has a structure highly homologous with that of COL4A1 which encodes the alpha 1(IV) chain. However, the COL4A5 gene contains 51 exons, or one less than COL4A1. The exon size pattern of the genes are similar, with 41 exons having identical sizes. All the exons were assigned to distinct EcoRI restriction fragments. The results may be useful for characterization of mutations in COL4A5 in patients with X chromosome-linked Alport syndrome.