Activation of prophenoloxidase A1 by an activating enzyme in Drosophila melanogaster.

An activating enzyme for prophenoloxidase A1 was isolated from pupae of Drosophila melanogaster, and the activation of purified prophenoloxidase A1 with this enzyme was analyzed. The purification included ammonium sulfate fractionation, DEAE-cellulose, Superdex 75, arginine-Sepharose and hydroxyapatite column chromatography. The prophenoloxidase activating enzyme was determined to be a 28.5-kDa protein consisting of a single polypeptide. The kinetics of the activation reactions was unusual in that the final levels of phenoloxidase activity varied depending on the initial concentrations of the activating enzyme, not those of the prophenoloxidase. The activation was effectively suppressed by the inhibitors of trypsin-type serine protease. The protein has amidolytic activity, and Boc-Val-Pro-Arg-MCA was the best substrate among the synthetic substrates examined. The molecular mass of the activated phenoloxidase was smaller than that of the prophenoloxidase, indicating that a 5-kDa peptide was released from the prophenoloxidase by limited proteolysis with the activating enzyme. The cleavage site of prophenoloxidase A1 was shown to be between Arg and Phe at positions 52 and 53.

Multiple bursitis--a case with an unusual skin manifestation.

Bursitis is a periarticular rheumatism which occurs as a result of trauma, infection, metabolic disease or rheumatoid arthritis. The disease is usually manifested as a solitary lesion except in a few reported cases of multiple lesions. We describe here a case of bursitis in a 58-year-old woman with multifocal cystic lesions containing sterile bloody or yellowish fluid in the four extremities. Serological abnormalities were also noted, suggesting the presence of rheumatoid arthritis or another autoimmune connective tissue disease.

Activation of prophenoloxidase with 2-propanol and other organic compounds in Drosophila melanogaster.

Activation with 2-propanol and other organic compounds of prophenoloxidase purified from pupae of Drosophila melanogaster was analyzed. A1, one of the two isozymes of the prophenoloxidase, could be activated with both an endogenous activating system and artificial organic compounds including alcohols. A1 was activated within 2 min after addition of 2-propanol. The phenoloxidase activity of A1, which had been activated with 2-propanol, decreased gradually by lowering the concentration of 2-propanol taking c 60 min to attain a low level, and the activity could be re-elevated at the re-introduction of 2-propanol. Thus the reversibility of the activation of A1 in response to the change of the concentration of 2-propanol in the activating mixture could be observed. Optimum concentration of 2-propanol for the rate of activation was 50%, optimum temperature was 30 degrees C and optimum pH was 7.5. The final level of the phenoloxidase activity, which had been activated with 2-propanol, was higher than that activated with the endogenous activating system. The activated state of A1 showed properties of a tyrosinase-type phenoloxidase. The results suggested that the activation of A1 with 2-propanol is caused by the reversible conformational change of the prophenoloxidase molecule.

Suppressive effect of sera from patients undergoing chronic hemodialysis on neutrophil chemiluminescence response.

To determine the mechanism of easy infectability of uremic patients, we studied the effect of sera from uremic patients who were undergoing chronic hemodialysis on the chemiluminescence (CL) response of polymorphonuclear leukocytes (PMN). The luminol-dependent CL response was examined following stimulation with phorbol myristate acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (FMLP). The patient's sera suppressed the CL response following stimulation by PMA, but not by FMLP. These findings suggest that sera from uremic patients undergoing hemodialysis contain a suppressive substance that suppresses the activation of PMNs by PMA.

The potential risk for subclavian vein occlusion in patients on haemodialysis.

Subclavian vein (SCV) stenosis or occlusion can be a late complication of temporary haemodialysis or following catheterisation for intravenous hyperalimentation. In five patients with prior catheterisation or trauma of the SCV, incapacitating oedema of the upper extremity developed only after the creation of ipsilateral arteriovenous (AV) fistulas for haemodialysis. The duration of the previous catheterisation was 2 to 4 weeks. Massive upper extremity oedema developed at 10 days to 22 months with an average of 11 months after the establishment of AV fistulas. Subclavian-axillary vein bypass using a ringed polytetrafluoroethylene graft was successful for one patient and ligation of the AV fistulae led to good results for the other three. In planning vascular access procedures in the upper extremity, venography should be mandatory to try to prevent such complications if a previous history of subclavian catheterisation exits.

Effects of intracellular ATP on calcium current in freshly dispersed single cells of guinea-pig portal vein.

In smooth muscle cells freshly dispersed from the guinea-pig portal vein, inward currents were recorded with the whole-cell clamp method in the presence of 2.4 mM Ca2+ under the condition in which outward K+ currents were suppressed and the effects of ATP in patch pipettes were studied. There was a large variation of the rate of current decay, the half-decay time ranging from 20 to 80 ms, but it was difficult to demonstrate clearly the presence of fast (T-type) and slow (L-type) Ca2+ channels based on threshold, the effects of changing holding potential, and of nicardipine, a dihydropyridine Ca2+ channel blocker. Intrapipette ATP had a weak potentiating effect on inward current, but did not seem to influence the correlation between peak current amplitude and current configuration. Cyanide (0.5 mM) reduced inward currents, particularly when ATP concentration was low and only limited recovery was observed. It was concluded that the amplitude and the rate of current decay of inward currents are not only determined by intracellular ATP, but also significantly influenced by some other factor, such as that involved in 'run-down' of Ca2+ currents.

Increase in calcium channel current by beta-adrenoceptor agonists in single smooth muscle cells isolated from porcine coronary artery.

1. The action of catecholamines (isoprenaline and noradrenaline) and forskolin on membrane currents was studied in single cells freshly dispersed from the pig coronary artery by use of the whole-cell clamp method, usually with electrodes containing CsCl. 2. In normal Krebs solution, with and without 30 mM tetraethylammonium (TEA) and 0.5 mM 4-aminopyridine, isoprenaline (1-5 microM) clearly increased the inward currents elicited by membrane depolarization, without affecting the holding current at -80 mV. The same effect was observed when the external Cl- was replaced with isethionate. The outward current recorded with K(+)-containing electrodes was not significantly affected by isoprenaline. 3. In the presence of 67 mM Ba2+ and 30 mM TEA, the maximum inward current recorded with CsCl containing electrodes was 119 +/- 7 pA (the mean +/- s.e.mean, n = 90) in cells where the current was larger than 30 pA. The L-type Ca2+ channel was considered to be responsible for these currents, based on the threshold voltage, the slow time course of decay, the large depolarization necessary to produce inactivation, and the high susceptibility to the Ca2+ channel antagonist, nicardipine. 4. Isoprenaline and noradrenaline increased the amplitude of inward currents evoked by depolarizing pulses. The maximum inward current was potentiated by 43 +/- 7% (n = 12) by isoprenaline and 39 +/- 10% by noradrenaline (n = 6) at a concentration of 1 microM. These effects were strongly inhibited by propranolol, but not phentolamine. Forskolin (10 microM) also potentiated the currents to a similar degree. 5. It is suggested that stimulation of beta 3-adrenoceptors increases the amplitude of inward currents through L-type Ca2 + channels in the pig coronary artery and that intracellular cyclic adenosine monophosphate is likely to be inolved in this action.

[Preoperative embolization with gelfoam powder for intracranial meningioma causing unusual peritumoral hemorrhage--with reference to the mechanism of hemorrhage].

Preoperative embolization for intracranial meningioma has been performed at many institutions and its effectiveness has been well recognized. The complications of embolization such as facial pain, fever and facial nerve palsy, et al, were mild and temporary except embolus migration into intracranial vessels, but a peritumoral hemorrhage due to preoperative embolization was extremely rare. Recently we have experienced such an unusual complication, then we describe this complication here and discuss the mechanism of hemorrhage briefly. A 73-year-old female who had the left falx meningioma underwent preoperative embolization with gelfoam powder through the transfemoral route. About 10 hours later, she developed disturbance of consciousness and right hemiplegia. At that time, CT scan showed peritumoral hemorrhage and an increase in midline shift. An emergency craniotomy was performed and total removal of the falx meningioma (Simpson grade II) and evacuation of the hematoma were done. The postoperative course was uneventful. We conclude that gelfoam powder (average particle size 40-60 mu) is a useful material for preoperative embolization but may at times cause peritumoral hemorrhage.

[Unusual case of depressed fracture of the posterior cranial fossa associated with the syndrome of acute central cervical spinal cord injury].

Linear fractures through the occipital bone are common, whereas depressed fractures in the posterior cranial fossa are rare because the occipital bone is protected by the surrounding thick muscles. The authors describe an unusual case of depressed fracture localized in the posterior cranial fossa associated with the syndrome of acute central cervical spinal cord injury. A 50-year-old female struck her face against the table and fell backward, while drunk, resulting in the bruise over the occipital region. Three days after injury she was transferred to our hospital because of progressive disturbance of consciousness, brain stem dysfunction and tetraplegia. Neurological examination on admission showed that she was drowsy, had tetraplegia and could not speak. However, she could obey commands only by moving her eyes and the ocular movements were normal in all directions except for horizontal nystagmus. Plain skull x-ray revealed a conspicuously depressed fracture in the posterior cranial fossa, but cervical spine x-ray showed neither fracture nor dislocation. Immediately suboccipital craniectomy was done and there were a thin subdural hematoma on the cerebellar surface, cerebellar contusion, and subarachnoid hemorrhage around the cisterna magna. Soon after operation impaired consciousness and paraplegia were improved, but recovery of both arms was delayed. Five months after injury, she still had left IX, X and XI nerve paresis, bilateral arm weakness, dysarthria, swallowing disturbance and bilateral sensory disturbance below C4 level. These findings indicated that she had sustained brain stem and cerebellar compression by the depressed fracture and also had suffered an acute central cervical spinal cord injury.

[Cerebral and pulmonary arteriovenous fistula with possible hereditary hemorrhagic telangiectasia: case report].

Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease) is a syndrome characterized by the presence of mucocutaneous telangiectasia, recurrent hemorrhage (epistaxis from nasal telangiectasia is by far the most common form), and hereditary occurrence. Hereditary hemorrhagic telangiectasia is thought not to be a simple mucocutaneous disease but a generalized vascular dysplasia, because multiple visceral organs and systems, including central nervous system, are involved. But, an involvement of the central nervous system in this disease is rare. We experienced a case with cerebral arteriovenous fistula that was also diagnosed as possible hereditary hemorrhagic telangiectasia. In this communication this case is reported and the relevant literature is reviewed. A 30-year-old male, who was diagnosed as having possible hereditary hemorrhagic telangiectasia, was found to have abnormal findings on head CT scan during the evaluation of his disease. So he was admitted to the neurosurgical department for further examination. He was also known to have pulmonary arteriovenous fistula (11.5% arteriovenous shunt) and secondary polycythemia (RBC 533 X 10(4)/mm3, Hb 17.6 g/dl, Ht 51%). His past medical history was noteworthy for several episodes of epistaxis since childhood. His uncle had also pulmonary arteriovenous fistula and was operated on at another hospital. On admission, he was alert and showed normal neurological findings. Routine x-ray of the skull showed abnormal thinning of the skull in the right parietal region. Computed tomograms showed a lobulated high-density mass in the right parietal lobe which was homogeneously enhanced after bolus injection of contrast material. Right carotid angiograms disclosed a dilated aneurysmal vein in the parietal lobe.(ABSTRACT TRUNCATED AT 250 WORDS)