Autoimmune haemolytic anaemias. V. Studies on the resistance against complement haemolysis of the red cells of patients with chronic cold agglutinin disease

Experiments are described the results of which sustain the hypothesis that resistance against complement haemolysis, which is a characteristic of the red cells of patients with chronic cold agglutinin disease, is due to the following mechanism: when red cells react with cold auto-agglutinins in vivo, they are either haemolysed immediately, or, due to an unknown factor, escape direct haemolysis. In the latter case β₁E and β₁A disappear from the cell membrane. To the sites where these proteins have been attached once, no new β₁E or β₁A molecules can be bound. Full complement activation thus becomes impossible.     

Rush Hymenoptera venom immunotherapy: a safe and practical protocol for high-risk patients

BACKGROUND: Hymenoptera venom immunotherapy in allergic patients is a well-established treatment modality for the prevention of systemic anaphylactic reactions caused by insect stings. A variety of therapy regimens exists, from conventional to rush and ultrarush modalities that operate on continuous or intermittent schedules. OBJECTIVE: The aim of this study was to report the 8-year experience with our rush venom immunotherapy regimen in predominantly high-risk patients and to compare data on safety and convenience with the results of 26 studies published from 1978 to 2001. METHODS: One hundred one patients allergic to bee, yellow jacket, or hornet venom were treated with rush Hymenoptera venom immunotherapy. Diagnosis and selection of patients for venom immunotherapy were carried out according to the recommendations of the European Academy of Allergology and Clinical Immunology. We used a 4-day regimen, and the incidence and nature of systemic reactions (SRs) were documented. Fifty-two patients were treated with honeybee venom, and 49 were treated with yellow jacket venom. RESULTS: One hundred (99%) patients reached the maintenance dose. We observed 8 injection-related SRs (0.47% of all injections given) in 7 (6.9%) patients. The number of SRs was higher in patients treated with bee venom extract (12%) compared with in patients receiving yellow jacket venom extract (2%). There was no significant difference in the risk of SRs between female and male patients. The incidence of SRs was considerably lower than the average of 17.8% reported in the literature. CONCLUSION: With a rush immunotherapy regimen over a time period of 8 years in predominantly high-risk patients, the incidence of SRs was low, despite the high number of patients with bee venom allergy, who are more likely to have side effects. Epinephrine as rescue medication was never necessary, and the regimen proved to be safe and convenient for both the patients and the medical staff.     

Activated protein C resistance shows an association with pregnancy-induced hypertension

A common mutation in the factor V gene, the Leiden mutation, is the most frequent genetic cause of resistance to activated protein C (APC). Recent studies have shown that the prevalence of APC resistance is associated with severe pregnancy-induced hypertension (PIH). Our objective was to determine whether the factor V Leiden mutation is more prevalent in patients who developed severe PIH than in normotensive pregnant women. In 70 women with a history of severe PIH, of whom 15 had pre-eclampsia, we investigated common coagulation factors as well as APC resistance (factor V related). We found that seven of these 70 women showed low values for APC. Out of these, five were heterozygous and none was homozygous for factor V Leiden mutation. In a control group of normotensive pregnant women we found a 3.0% rate of APC resistance and a 3.0% rate of carriers of the Leiden mutation. These results indicate a significantly higher prevalence of both APC resistance and factor V Leiden mutation in women with severe PIH. Placental infarctions and micro-embolisms are considered to be one of the principle pathophysiological changes in severe PIH. Our results suggest that APC resistance is a risk factor for severe PIH, in addition to its well-known role in macrothrombo-embolism.     

Human papillomavirus type 16 DNA sequence

The complete nucleotide sequence of HPV16 DNA (7904 bp) cloned from an invasive cervical carcinoma was determined. Homology comparisons allowed us to align the major open reading frames with the other published papilloma virus DNA sequences. The general organization of the open reading frames is similar to that of the other four papillomavirus (BPV1, HPV1a, HPV6b, CRPV) already sequenced. The sequence reveals an interruption of the reading frame coding for a suspected E1 protein.     

Effect of low-frequency repetitive transcranial magnetic stimulation on interhemispheric inhibition

We studied the effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) on the excitability of interhemispheric connections in 13 right-handed healthy volunteers. TMS was performed using figure-eight coils, and surface electromyography (EMG) was recorded from both first dorsal interosseous (FDI) muscles. A paired-pulse method with a conditioning stimulus (CS) to the motor cortex (M1) followed by a test stimulus to the opposite M1 was used to study the interhemispheric inhibition (ppIHI). Both CS and TS were adjusted to produce motor-evoked potentials of approximately 1 mV in the contralateral FDI muscles. After baseline measurement of right-to-left IHI (pre-RIHI) and left-to-right IHI (pre-LIHI), rTMS was applied over left M1 at 1 Hz with 900 stimuli at 115% of resting motor threshold. After rTMS, ppIHI was studied using both the pre-rTMS CS (post-RIHI and post-LIHI) and an adjusted post-rTMS CS set to produce 1-mV motor evoked potentials (MEPs; post-RIHI(adj) and post-LIHI(adj)). The TS was set to produce 1-mV MEPs. There was a significant reduction in post-LIHI (P = 0.0049) and post-LIHI(adj) (P = 0.0169) compared with pre-LIHI at both interstimulus intervals of 10 and 40 ms. Post-RIHI was significantly reduced compared with pre-RIHI (P = 0.0015) but pre-RIHI and post-RIHI(adj) were not significantly different. We conclude that 1-Hz rTMS reduces IHI in both directions but is predominantly from the stimulated to the unstimulated hemisphere. Low-frequency rTMS may be used to modulate the excitability of IHI circuits. Treatment protocols using low-frequency rTMS to reduce cortical excitability in neurological and psychiatric conditions need to take into account their effects on IHI.     

Raman spectroscopic study of glutaraldehyde-stabilized collagen and pericardium tissue

For the first time, Raman spectroscopy has been employed to investigate formation of cross-links in collagen and porcine pericardium tissue upon glutaraldehyde (GA) treatment. GA treatment causes a very high fluorescence background, which overlaps Raman bands. It has been found that short fixation time, i.e. 2 h, reduces background radiation significantly, providing new possibilities for studying changes in molecular structure of collagen upon GA modification. The observed changes in position and intensity of Raman bands allowed us to recognize different types of GA-collagen interactions. Strong spectral evidence has been found for the peptide contribution to the formation of the GA-collagen cross-links and for the formation of secondary amines via Schiff base intermediates, and pyridinium-type cross-links. The results also revealed that different hydration levels and a more complex structure of intact tissue in comparison to collagen preparation strongly influence the formation of a GA cross-linking network, e.g. ether-type bond is preferred to form in a less hydrated collagen preparation. Our results have shown that GA treatment causes an increase in water content of pericardium tissue and collagen.     

Impulse patterns of Ia afferents and Ia-activated DSCT neurons during sinusoidal muscle stretch in cats

Summary The cat gastrocnemius muscles of one hind leg were stretched sinusoidally with amplitudes between 10 m and 2.5 mm and frequencies between 1 and 30 Hz. The stretch response of deefferented muscle spindle afferents and of Ia-activated cells within Clarke's column were investigated by means of extra-cellular recordings of action potentials. The responses to 20–50 cycles were displayed in impulse patterns (raster diagrams) of the responding action potentials. The impulse patterns of Ia afferents exhibited a high degree of phase-locking (regularity) on the stretch cycle of amplitudes of about 50 m at 3 Hz and all higher amplitudes or frequencies. At comparable stretch parameters the regularity in Ia afferents was 4–6 times larger than in Ia-activated DSCT neurons. The regularity in the DSCT patterns increased with an increase in stretch frequency. The impulse patterns of DSCT cells exhibited a high negative correlation between successive interspike intervals (–0.4 to –0.6) at low stretch frequencies (<3 Hz), which decreased with an increase in stretch frequency.     

Regional brain variations of cytochrome oxidase activity and motor coordination in Lurcher mutant mice

Lurcher mutant mice are characterized by massive degeneration of cerebellar Purkinje cells and granule cells and by deficits in motor coordination. Regional brain variations of cytochrome oxidase (CO) activity were analyzed to identify those brain regions with abnormal metabolic activity as a secondary consequence of the cerebellar atrophy and to establish the relationship between CO activity and motor deficits. Lurcher mutants had higher CO activity in all three cerebellar deep nuclei than normal littermate controls of the same background strain. Higher CO activity was also found in Lurcher mutants in brain regions directly connected to the cerebellum, such as the lateral vestibular nucleus, the cochlear nucleus, the red nucleus, the ventrolateral thalamus, the dorsal raphe, the interpeduncular nucleus, and the inferior colliculus. By contrast, there was a sharp decrease in CO activity in the inferior olive. As for brain regions not directly connected to the cerebellum, higher CO activity was observed in the trigeminal motor nucleus and the CA1 molecular layer of the hippocampus, which highlights probable transsynaptic alterations as a secondary consequence of cerebellar atrophy. A positive correlation between CO activity in the red nucleus and latencies before falling in two motor-coordination tests indicates that a compensatory increase of metabolic activity in a cerebellar efferent region is associated with improved behavior. Received: 15 September 1997 / Accepted: 3 March 1998     

Expression of cathepsin K in lung epithelial cells

Alveolar and bronchial epithelial cells have been shown to have regulatory functions in the maintenance of lung structure and function. Recent evidence supports the premise that these cells can synthesize a variety of extracellular matrix components in vitro, suggesting an active participation in connective tissue remodeling. Their possible role in extracellular matrix degradation, however, is less clear. This study addresses the question of whether alveolar and bronchial epithelial cells express the highly collagenolytic and elastinolytic cysteine proteinase cathepsin K, which has recently been newly described. We provide evidence that the epithelial cell lines A549 and BEAS-2B are capable of expressing cathepsin K messenger RNA. Furthermore, we show that cathepsin K is expressed in normal bronchial epithelial cells. Western blot analyses of human lung-tissue lysates revealed specific immunoreactivity at molecular weights of 46 and 27 kD, corresponding to the procathepsin and the mature cathepsin K. Immunohistochemical analyses showed a pronounced staining of bronchial epithelial cells and in single alveolar epithelial cells. Using a specific fluorogenic cytochemical assay, the intracellular activity of the enzyme was localized. These findings demonstrate that bronchial and alveolar epithelial cells are capable of expressing cathepsin K, which could be of considerable importance for remodeling processes of the extracellular matrix in the lung.