Plasminogen activators in tissue extract of aural cholesteatoma.

Using a biochemical technique, the authors characterized and identified the plasminogen activator (PA) derived from tissue extracts of six aural cholesteatomas. The results of fibrin zymography indicated that the tissue extracts of two cholesteatomas demonstrated two lytic zones on fibrin-agarose plates. One of the lytic zones was at about 72 kd, while the other zone was at about 64 kd. Using various goat immunoglobulin G (IgG)-containing antibodies (anti-human uterine tissue type PA (t-PA), anti-human low-molecular-weight (LMW) urokinase, and nonspecific goat IgG) and plasminogen-free fibrin-agarose plates, we confirmed that the cholesteatoma tissue extracts contained 72 kd t-PA and 64 kd urokinase type PA (u-PA). Furthermore, we measured the t-PA and u-PA activities in the tissue extracts selectively by parabolic rate assay. In order to estimate the PA activity, we developed optimal conditions for this assay. The specific t-PA activity ranged from 0.03 to 0.43 mIU/micrograms-protein and the specific u-PA activity ranged from 0 to 0.35 mIU/microgram-protein. The highest percentage of u-PA with respect to the total PA activity was 44.9%. However, in four of the six cases, we failed to detect u-PA activity. In the present study, we thus clarified the presence of PAs in tissue extracts of aural cholesteatomas. Furthermore, we confirmed that measureable u-PA occurred in some tissue extracts. We anticipate that the u-PA in inflammatory tissues plays an important role in the degradation of the extracellular matrix via the formation of plasmin and collagenases.

Inhalation of platelet-activating factor increases respiratory resistance in rats: determination by means of an astograph under nonanesthetized conditions.

Intratracheal administration of platelet-activating factor (PAF) to dogs, baboons, and humans has been shown to induce hyperreactivity of the airways and contraction of the smooth muscle. However, it has not yet been reported whether intratracheal administration of PAF to rats induces hyperreactivity. In the present study, the authors estimated the respiratory resistance of rats during intratracheal administration of PAF in order to evaluate the reactivity of the airways to PAF. In both the nonsensitized group and the sensitized group of rats, intratracheal administration of PAF induced an increase in respiratory resistance. The results obtained clarify that responsiveness to PAF exists in the airways of rats.

Evaluation of provocation tests in tonsillogenic focal infection from the standpoint of fibrinolytic activity.

In this paper, we carried out provocation tests by means of ultra-short wave stimulation in patients with focal infection including palmoplantar pustulosis and examined the changes in fibrinolytic activity of the circulating blood. In the positive group with palmoplantar pustulosis, the t-PA level was slightly increased after the provocation and the FDP level in the positive group was increased. On the other hand, the AT-III activity in the positive group with palmoplantar pustulosis was decreased and the antiplasmin activity in the positive group was increased. The changes of antiplasmin activity observed in this experiment did not correspond with the pathophysiological explanation of an increased fibrinolytic activity in the circulating blood. It was suggested that a positive provocation test is accompanied by an increase in fibrinolytic activity in the circulating blood of patients with focal infection of the tonsil, and the increase in fibrinolytic activity is closely related to the positiveness of the provocation test.

Plasminogen activator derived from tonsillar lymphocytes of rabbits with arthus tonsillitis.

As an experimental model of human tonsillitis, Arthus tonsillitis of the rabbit was produced. In a previous paper, we demonstrated that an increased fibrinolytic activity in the circulating blood and increased proteolytic activity of the local tissue with Arthus tonsillitis were observed. In the present study, the mechanism of the increased proteolytic activity at the local site (tonsil with Arthus-type tonsillitis) was examined using cell cultures of lymphocytes originating from the tonsil with Arthus-type inflammation. That is, lymphocytes isolated from tonsil tissue of the rabbit were cultured in a culture medium for the short term. After culture, the used medium was collected and the presence of plasminogen activator in the culture medium and lymphocytes was investigated. It was clarified that plasminogen activator did exist in the culture medium of lymphocytes originating from the tonsil of rabbits with Arthus tonsillitis. Furthermore, addition of T cell growth factor to the culture medium of lymphocytes derived from non-treated tonsil induced the development of plasminogen activator in that culture medium. However, addition of B cell growth factor did not lead to the development of plasminogen activator activity in the culture medium. These results suggest that plasminogen activator originating from lymphocytes of the tonsil may play an important role in the increased proteolytic activity observed at the local site of Arthus tonsillitis.

Histamine release from rabbit platelets by platelet-activating factor (PAF).

In this study, we examined firstly whether PAF could activate washed platelets of rabbits and release ATP from the platelets, secondly whether activated platelets could release histamine, and thirdly whether certain antagonists of PAF could inhibit the release of histamine from platelets. The results obtained in these experiments may be summarized as follows. 1) Release of ATP was increased with enhanced platelet aggregation by PAF. At 3.4 x 10(-7) M of PAF, the maximal aggregation rate of platelets was about 70% and the concentration of released ATP was 1.6 x 10(-5) M. 2) After aggregated platelets induced by PAF had been sonicated and centrifuged, the resultant supernatant could cause contraction of the guinea pig ileum. This contraction was inhibited by the antihistaminic agents, cimetidine and pyrilamine. Furthermore, the histamine content of the supernatant was about 3.7 micrograms/ml (platelet count, 30 x 10(4)/microliter). 3) At 10(-5) M of CV-3988, the inhibitory ratio of PAF-induced aggregation was 35% and that of histamine release was 50%. On the other hand, at 5 x 10(-7) M of CV-6209, the inhibitory ratio of PAF-induced aggregation was 35% and that of histamine release was about 30%. From the above results, it was clear that PAF-activated platelets could release histamine. In addition, it is suggested that a direct relationship between PAF and platelets may exist in the process of allergic reactions, and histamine from PAF-activated platelets may modify allergic reactions.

[Cochlear implants]. / Cochlear Implants.

Since the middle of 1984, the HNO-Klinik der Medizinischen Hochschule Hannover has provided deaf adults with a 22-channel cochlear implant (CI) device of Clark-NUCLEUS. The digital working system consists of an implantable stimulator/receiver and an externally worn speech processor. Energy and signals are transmitted transcutaneously via a transmitter coil. During the prevailing 26 operations (April 1986) the electrode array could be inserted at least 17 mm into the cochlea. The threshold and comfort levels of all patients were adjusted very quickly; the dynamic range usually grows during the first postoperative weeks. The individual rehabilitation results vary greatly, but all patients show a significant increase of vowel and consonant comprehension while using the speech processor and an improvement of words understood per minute in speech tracking from lip-reading alone to lip-reading with speech processor. Four months after surgery seven of 17 patients (group I) are able to understand on average 42.7 words per minute by speech tracking without lip-reading. Six patients (group II) recognise 69.2% of vowels and 42.5% of consonants by speech processor alone. Four patients (group III) can correctly repeat only vowels (52.3%) without lip-reading, but using the speech processor together with lip reading they have an improvement in consonant understanding of 37.9% and under freefield conditions they are able to understand up to 17.8% numbers of the Freiburg speech test.