Serum immunoglobulin G antibody to Porphyromonas gingivalis in rapidly progressive periodontitis: titer, avidity, and subclass distribution.

Porphyromonas gingivalis is a suspected pathogen in rapidly progressive periodontitis (RPP). We have determined the anti-P. gingivalis serum immunoglobulin G (IgG) isotype response and avidity and the subclass titer distributions for 30 RPP patients and 30 age-, sex-, and race-matched healthy subjects by using enzyme-linked immunosorbent assay technology. Patients and control subjects were classified as seropositive if their total IgG response to P. gingivalis was twofold or more than the median response in healthy subjects. The predominant antibody responses for both patients and healthy subjects were IgG2 and IgG3, with a subclass order of IgG2 greater than IgG3 greater than IgG1 greater than IgG4. The avidity of the IgG response was highest for the seropositive healthy subjects and was no different between seronegative and seropositive RPP patients. The subclass antibody responses did not depend on gender, and there were no correlations between titer, avidity, or subclass with disease severity in the RPP patients as measured by pocket depth or bone loss on dental X rays. The seronegative RPP patients exhibited antibody responses that were greater than the responses of seronegative healthy subjects for all four subclasses, while the seropositive RPP patients had higher IgG1 and IgG4 levels than seropositive healthy subjects. These findings are consistent with the hypothesis that both carbohydrate and protein antigens are important in the IgG response to P. gingivalis. The relative predominance of IgG2, a subclass which lacks strong complement fixation and opsonic properties, and the low avidity of patient anti-P. gingivalis IgG antibodies suggest that humoral responsiveness to infection with P. gingivalis may be ineffective in clearing this organism.     

Combining EL4-B5-based B-cell stimulation and phage display technology for the successful isolation of human anti-Scl-70 autoantibody fragments

Scl-70 is the major antigen recognised by autoantibodies in the sera of patients with systemic sclerosis (SSc). The autoantibodies that specifically react with Scl-70 are highly characteristic of the disease and represent valuable markers for the diagnosis of SSc. We describe a novel strategy for cloning autoantibody fragments starting with a small blood sample from an SSc patient. B cells isolated from the collected peripheral blood mononuclear cells (PBMCs) were cultured in vitro using the EL4-B5 system. Anti-Scl-70 IgG-producing cells were pooled for RNA preparation followed by the generation of phagemid libraries of approximately 10(7) independent single-chain Fvs (scFvs). The screening of these libraries by phage display allowed us to isolate four anti-Scl-70 scFvs following three rounds of biopanning. About 10 times more starting blood material was needed to generate scFv libraries of similar size from PBMCs of an SSc patient and only two anti-Scl-70 scFvs were isolated after three rounds of phage selection. Together, this work shows that functional autoantibody fragments can be advantageously cloned after in vitro expansion of B cells. The isolated anti-Scl-70 autoantibody fragments represent useful tools for calibrating SSc diagnostic assays.     

The use of successive blood-pressure measurements to estimate blood-pressure variability

Multiple daily, self-determined blood-pressure measurements were obtained from 254 hypertensive patients for 1 month. In an effort to establish a practical and reliable technique for estimating blood-pressure variability, standard deviations from three (at one time of day) or nine (throughout the day) successive self-determinations were compared with a reference value, taken to be the standard deviation for the entire month (252 determinations per subject). Neither the standard deviation of three measures taken on one occasion nor that of nine measures taken throughout the day correlated well with the reference value (average R₃=.21 for SBP, .20 for DBP; average R₉=.39 for SBP, .38 for DBP). However, when a sample consisting of 12 measures (taken three at a time, at the same time of day, weekly for 4 weeks) was used, the average correlation rose to .60 for SBP and .54 for DBP. Thus, it appears that 12 samples taken in this way provide a reliable estimate of the standard deviation for an entire month, and it is suggested that this sampling technique also would enhance the reliability of conclusions drawn from assessments of the prognostic value of blood-pressure variability.     

Defective peroxisomal catabolism of branched fatty acyl coenzyme A in mice lacking the sterol carrier protein-2/sterol carrier protein-x gene function

Gene targeting in mice was used to investigate the unknown function of Scp2, encoding sterol carrier protein-2 (SCP2; a peroxisomal lipid carrier) and sterol carrier protein-x (SCPx; a fusion protein between SCP2 and a peroxisomal thiolase). Complete deficiency of SCP2 and SCPx was associated with marked alterations in gene expression, peroxisome proliferation, hypolipidemia, impaired body weight control, and neuropathy. Along with these abnormalities, catabolism of methyl-branched fatty acyl CoAs was impaired. The defect became evident from up to 10-fold accumulation of the tetramethyl-branched fatty acid phytanic acid in Scp2(−/−) mice. Further characterization supported that the gene disruption led to inefficient import of phytanoyl-CoA into peroxisomes and to defective thiolytic cleavage of 3-ketopristanoyl-CoA. These results corresponded to high-affinity binding of phytanoyl-CoA to the recombinant rat SCP2 protein, as well as high 3-ketopristanoyl-CoA thiolase activity of the recombinant rat SCPx protein.     

Breakdown of the round window membrane permeability barrier evoked by streptolysin O: possible etiologic role in development of sensorineural hearing loss in acute otitis media.

Sensorineural hearing loss is a common sequela of acute and chronic otitis media, and the round window membrane (RWM) is currently being considered as a major route for noxious agents to pass from the middle ear cavity to the cochlea. Streptococcus pneumoniae, a major causative agent of otitis media, and Streptococcus pyogenes A produce molecularly related toxins, pneumolysin and streptolysin O (SLO), that form large pores in target membranes. In this study, we analyzed the effects of SLO on the permeability of the RWM. Resected RWMs from a total of 104 guinea pigs were embedded between two chambers of an in vitro system. One chamber was designated as the tympanal (cis) compartment, and the other was designated as the inner ear (trans) compartment. The permeability of normal and SLO-damaged RWMs towards Na+, [14C]mannitol, and proteins was investigated. SLO evoked permeability defects dose dependently in the RWM with fluxes of both Na+ and [14C]mannitol being demonstrable over a time span of up to 8 h. Serum proteins and radioiodinated SLO were also shown to pass through the damage RWM. Scanning electron microscopy revealed the morphological correlates to these results. We propose that damage to the RWM by potent pore-forming cytolysins leads to leakage of ions from the perilymph. Ionic disequilibrium and passage of noxious macromolecules to the cochlea could contribute to disturbances of the inner ear function.     

Antibodies to nucleic acids in myasthenia gravis.

An increased frequency of antibodies to native DNA, thymocytes, and striated muscle was found in patients with myasthenia gravis (MG). The prevalence of such antibodies lends considerable support to the concept of MG as an autoimmune disorder and militates in favor of major abnormalities in the thymic dependent immune system. There was no correlation between serum-blocking activity to acetylcholine receptor protein and antibodies to thymocytes.     

A fourth case of ring chromosome 7

An 8-year-old child with a ring chromosome 7 is presented, the first female and the fourth such individual to be described. The associated anomalies were rather benign: she presented with short stature, minor skeletal alterations, and normal intelligence. The only truly striking feature was the presence of multiple large, pigmented naevi, suggestive of a hamartomatous origin, but unlike those typical of any particular syndrome. Though other ring 7 patients have had naevus flammeus, and one had cafk-au-lait spots, our proband is the first with an anomaly of chromosome 7 to have such extensive lesions. These four cases of ring 7, which show great phenotypic variation, are reviewed, and the clinical presentation of the proband is also compared with that of patients suffering from terminal, interstitial and translocation-derived 7p and 7q deletions. The formation and behaviour of ring chromosomes are discussed, as are the cytogenetic factors which may influence their phenotypic expression.     

Der Tagesgang der Phasenkoppelung zwischen Herzschlag und Atmung in Ruhe und seine Beeinflussung durch dosierte Arbeitsbelastung

Zusammenfassung An insgesamt 33 gesunden Versuchspersonen im Alter von 18–32 Jahren wurde der Tagesgang der Phasenkoppelung zwischen Herzschlag (R-Zacke im EKG) und Atmung (Inspirationsbeginn) mit dem Koincidenzmeßgerät Synchromet unter verschiedenen Bedingungen untersucht. Bei 10 Probanden erfolgten die Messungen bei Bettruhe in einstündigen Abständen, weitere 10 Personen wurden alle 2 Std im Anschluß an die Koppelungsmessung mit dosierter Tretkurbelarbeit belastet, die übrigen 13 Probanden nur in vierstündigen Abständen, wobei die Phasenkoppelung zweistündlich kontrolliert wurde.In der Ruhegruppe fand sich im Mittel ein signifikanter tagesrhythmischer Gang des Koppelungsgrades mit einem nächtlichen Maximum gegen 1.00 Uhr und einem Minimum zwischen 12.00 und 17.00 Uhr. Die individuellen Tagesamplituden des Koppelungsgrades betragen zwischen 2,8 und 11,6 E (Mittelwert 6,4); sie waren um so größer, je höher das individuelle Tagesniveau von Pulsfrequenz und Puls-Atem-Quotient lag. Die individuellen Tagesmaxima lagen in Ruhe zu 85% in der Nachthälfte (19.00-7.00 Uhr), die Minima zu 75% am Tage (7.00-19.00 Uhr).Bei vierstündlich wiederholter Arbeitsbelastung war die Amplitude im mittleren Tagesgang des Koppelungsgrades, der zwei Gipfel mit 12stündigem Abstand aufwies, signifikant kleiner, bei zweistündlicher Belastungsfolge fehlte sie vollständig. Die individuellen Amplitudenwerte betrugen zwischen 1,3 und 7,5 (Mittelwert 3,1) bzw. 1,1 und 5,5 E (Mittelwert 2,8). Die individuellen Tagesmaxima lagen bei vierstündlicher Belastung noch zu 65% in der Nachthälfte, bei zweistündlicher Belastung nur noch zu 60%, die entsprechende Minimahäufigkeit in der Tageshälfte betrug 58 bzw. 50%. Die Häufigkeitsverteilung der Maxima und Minima war vorzugsweise zweigipfelig mit etwa 12stündigen Gipfelabständen.Im Gegensatz zu der Abschwächung bzw. Unterdrückung der nächtlichen Zunahme des Koppelungsgrades näherte sich das mittlere Frequenzverhältnis aus Puls und Atmung auch in den Belastungsgruppen während der Nacht der Norm 41 an. Der mittlere Tagesgang der Herzfrequenz war bei ähnlichem Niveau aller drei Gruppen nur bei vierstündlicher Belastungsfolge deutlich zweigipfelig mit 12stündigem Gipfelabstand.Die tagesrhythmische Schwankung des Koppelungsgrades wird auf vegetative Umstellungen zurückgeführt, die nicht unmittelbar an den Schlaf gebunden sind. Aus den Befunden bei Arbeitsbelastung wird geschlossen, daß die Phasenkoordination zwischen Herzschlag und Atmung schon durch leichte Arbeitsbelastung nach-haltig gestört wird und längere Erholungszeiten benötigt als Frequenz und Frequenzkoordination beider Rhythmen. Die Phasenkoppelung wird daher als empfindlichster Indicator für die Erholungsvorgänge im Bereich der rhythmischen Koordination angesehen.     

Association analysis of a polymorphism in the G‐protein stimulatory α subunit in patients with major depression*

Growing evidence suggests that G‐proteins may be involved in pathogenesis and treatment of affective disorders. Several studies have reported altered levels and/or activities of stimulatory G‐proteins in depression. The aim of this study was to investigate whether a polymorphism in the stimulatory α subunit of G‐proteins (T/C point mutation in exon 5; ATT → ATC at codon 131) is associated with major depression or response to antidepressant treatment. Therefore, we performed a case‐control association study with 212 depressive patients and 137 healthy, unrelated controls. There was no evidence for an association between the investigated polymorphism in the Gα_s gene and major depression, as well as to treatment response. The results of our study are in concordance with recently published findings which do not support the hypothesis that the gene for the stimulatory α subunit of G‐proteins is a major susceptibility factor in the pathophysiology of major depression. © 2002 Wiley‐Liss, Inc.