Immunological identity of the two different molecular mass constitutive subunits of liver arginase

A detailed understanding of the regulatory mechanisms of arginase in the cell will depend on the clarification of the origin of the two different molecular mass subunits and on the arrangements of them to constitute the native enzyme. Here, we show the immunological recognition of the 39.5 and 37.0 kDa subunits of arginase by antibodies against both subunits. We also find that the subunit stoichiometry (39.5 kDa: 37.0 kDa) present in purified arginase preparations as well as in fresh isolated microsomes and cytoplasm corresponds to 3:1, indicating high prevalence of a constant arrangement of the constitutive subunits of arginase. These findings represent evidence for a limited posttranscriptional or posttranslational modification of only a fraction of the synthesized arginase in liver.

Kinetics of manganese reconstitution and thiol group exposition in dialyzed rat mammary gland arginase

1. Rat mammary gland arginase is a metallo-enzyme dependent on Mn2+, which can be only partially substituted by Cd2+. 2. Reconstitution of the activity of dialyzed arginase by manganese is a two-phase process; the second phase is independent of the cation concentration, with a half-time recovery (t1/2) of 10.77 min. 3. The apparent Km for Mn2+ is 280 microM and 10.5 microM for enzyme dialyzed for 24 and 72 hr, respectively. 4. Treatment with 5 mM EDTA at pH 6 totally inhibits enzyme activity, which is reconstituted by Mn2+. 5. Results obtained with iodoacetamide treatment suggest the existence of sulphydryl groups accessible only when the enzyme is dialyzed.

Parallel induction of nitric oxide and glucose-6-phosphate dehydrogenase in activated bone marrow derived macrophages

The production of nitric oxide (NO.) and the induction of glucose-6-phosphate dehydrogenase by lipopolysaccharides (LPS) from different sources was studied in bone marrow derived macrophages (BMM phi). NO. production was found to be linked to the induction of glucose-6-phosphate dehydrogenase, suggesting the possible involvement of this enzyme in the cytotoxic mechanism resulting from the release of NO. by activated macrophages.

Lumbar posterior marginal node (LPMN) in adults. Report of fifteen cases

This report concerns 15 adults (nine men and six women) who experienced lumbar and sciatic pain associated with an unusual defect of the edges of the vertebral bodies together with a small bony ridge protruding into the spinal canal. This lesion was well demonstrated by computed tomography and easily differentiated from the posterior longitudinal ligament or herniated disc calcifications, as well as from posterior degenerative ridge osteophytes. This lesion looked like the so-called lumbar posterior marginal node. First described in adolescents, this entity was considered as a traumatic fracture of the posterior ring apophysis. Recently, identical cases were noted in young adults in the absence of previous trauma, which were a particular type of marginal cartilaginous node. In the cases reported here, the computed tomographic scans suggested several mechanisms of formation of the vertebral lesion: a variant of marginal cartilaginous nodes; traumatic avulsion; avulsion related to disc herniation; and fusion of the avulsed bony fragment with the vertebral body.

Unfolding and trypsin inactivation studies reveal a conformation drift of glucose-6-phosphate dehydrogenase upon binding of NADP

Binding of NADP to glucose-6-phosphate dehydrogenase (G6PD) from Dicentrarchus labrax liver has stabilized its native structure against thermal inactivation, guanidine hydrochloride unfolding and inactivation by tryptic digestion. The time-course of G6PD inactivation by guanidine hydrochloride in the presence of NADP has provided experimental evidence in favor of a conformational drift upon NADP binding to the bass enzyme. Based on the inactivation patterns obtained when the enzyme was treated with guanidine hydrochloride and trypsin, it is proposed that the enzyme conformation induced upon NADP binding is in slow equilibrium with the conformation stabilized in the absence of NADP. FPLC studies have shown that micromolar concentrations of NADP induced oligomerization of G6PD. In addition, the different K0.5 values of NADP binding to the enzyme, ranging from 1-2 microM (from trypsin inactivation) to 90 microM (from titration of the intrinsic fluorescence), suggest a step-wise binding of NADP to the oligomer, with negative cooperativity in the saturation process.

An arginine regulated gamma-guanidobutyrate ureahydrolase from tench liver (Tinca tinca L.)

A gamma-guanidobutyrate ureahydrolase isolated from tench liver has been characterized. Some of its physicochemical properties like pH effect and thermal stability resemble those of arginases, however it shows some peculiarities that makes it different from arginases and other amidino hydrolases. Thus cation requirement is not as strong as in arginases, and the Km value for gamma-guanido-butyric acid (230 +/- 25 mM) is shifted to a lower value (45 +/- 5 mM) by 5 mM arginine. The possible regulatory role of arginine on gamma-guanidobutyrate ureahydrolase activity is discussed.

Physico-chemical properties of hepatocyte plasma-membrane-bound arginase

Rat liver plasma-membrane-bound arginase was investigated in order to obtain data regarding its physico-chemical properties. Arginase bound to plasma membrane presented a specific activity of 0.74 +/- 0.09 IU/mg for the fully-activated enzyme, the pH of maximum activity being 9.8. Maximum stability was recorded at two pH values, 7 and 10.5 respectively. Mn2+ activated the enzyme, while Cu2+ and Zn2+, and to a lesser extend Co2+, showed a strong inhibitory effect. Ca2+ and Mg2+ had no effect at the concentrations assayed. The influence of temperature was studied in the presence and in the absence of Mn2+. The enzyme was stable up to 65 degrees C in both cases. Membrane- bound arginase showed an activation energy of 11.5 +/- 1.4 Kcal/mol between 20 and 40 degrees C, and 13.3 +/- 2.5 Kcal/mol between 40 and 60 degrees C. The Q10 for the same temperature ranges were 1.78 and 1.9 respectively. The membrane-bound enzyme presented two different Michaelis constants, one with high affinity (2.05 +/- 0.73 mM) and the other with low affinity for arginine (130 +/- 27.2 mM). Solubilized arginase showed very similar values. Among all the structural analogous assayed, only L-canavanine proved to be substrate for arginase, with and L-arginine/L-canavanine hydrolysis ratio of 5.8 +/- 0.28. No reactivity was found between plasma-membrane-bound arginase and anti-rat liver arginase antibodies raised in rabbits.

Radiation necrosis of the brain: time of onset and incidence related to total dose and fractionation of radiation

Clinical deterioration during or after brain irradiation may be due to progression of neoplasm or radiation induced necrosis of the neoplasm and/or of normal brain tissues, or a combination of all. Eight patients with histologically documented radiation induced lesions of the brain are included in this study. The radiation therapy included the fractional schedule, group A, who received 280 to 300 rads daily, to a total dose of 4500 to 5000 rads and weekly exposure did not exceed 900 rads. Group B patients were exposed to 850 rads, daily dose on day 1, 3, 21 and 23 to a total dose of 3400 rads. The incidence of radiation induced lesions of brain was 3.4% in patients group A and 8.7% in group B patients (without statistical significance). The median time of onset of these lesions after completion of radiation therapy was significantly shorter in group B patients (8.5 months) as opposed to group A patients (21 months).

[Fractures and dislocations of the lumbar vertebrae (author's transl)]

The authors report 6 cases of fracture and dislocation of the lower lumbar vertebrae (L3, L4, L5) and note that they were usually lesions following violent trauma usually in hyperflexion. The following were treated 1 dislocation L3-L4, 2 dislocations L4-L5, 2 comminuted fractures of L4, 1 fracture of L5, and included in all cases intersomatic arthrodesis at one (five cases) level or two levels (one case) and one posterior internal fixation with Kempf's material. The simplicity of the follow up and the stability of the fixation, permit us to propose the method for all unstable lesions of the lower lumbar vertebrae.

[Recent fractures of the dorso-lumbar spine. Reduction by the double shroud technique (author's transl)]

The use of posterior osteosynthesis in traumatic pathology of the dorso-lumbar spine, entails some throught about the time maintenance of the quality of the reduction and the solidity of equipment. The observation of the advantages and inconveniences of different methods has led us to the double shroud technique. The simultaneous use of Harrington's and Roy Camille's materials gives an excellent reduction from all points of view. Moreover the double shroud technique improves the stability of posterior osteosynthesis.

[A polygraphic, haemodynamic and metabolic study of 2 cases of the "locked-in" syndrome (author's transl)]

The sleep-waking pattern, cerebral blood flow (CBF) and cerebral metabolism have been studied in 2 cases of the "locked-in" syndrome, one traumatic, the other vascular in origin. Studies were performed in the third week in the first case and the seventh in the second. A lesion of the ventral pons was suggested clinically and neuroradiologically. The waking EEG was composed of alpha and theta activity. Different stages of slow wave sleep were diminished in quantity (NREM) as was paradoxical sleep (REM). The basal cerebral blood flow (CBF) was increased by 30 p. 100 compared to normals. Cerebral oxygen consumption was normal. The cerebral hyperaemia was evenly distributed and was associated with a failure of autoregulation. The vascular response to CO2 was normal, however. The E.E.G. findings, haemodynamic and metabolic studies confirmed a pontine lesion as the cause of the "locked-in" syndrome in contrast to akinetic mutism where the lesion is in the mid-brain.

[Inseparable prognostic value of spinothalamic and corticospinal functions in severe spinal cord injuries]

In severe spinal cord trauma with initial complete paraplegia or tetraplegia, even the smallest recovery of sensibility to pain or motor function has an obvious prognostical value as it results from the study of 112 spinal injuries. For the motor aspect it is well known from experimental work and in man that even a small part of a single pyramidal tract in the spinal cord can take in charge the bilateral motricity of the limbs. It remains exceptional in severe spinal cord injury that recovery of motricity is not followed by a return of pain sens. In the lateral funiculus of the cord the sensitive and pyramidal tracts belongs to a same anastomotic vascular area between the central and peripherical circulatory streams. In physiological conditions this intermediate circulatory stream is poorly functional. But in severe spinal cord trauma with reduction of central blood flow the adjacent spinothalamic and corticospinal tracts survive in couple on the basis of the same anastomotic vascular area: from this results the prognostical unity that belongs to pain sens and motricity.

Embolization of cerebral angiomas by catheterization of cortical arteries

A method of combined direct embolization of submillimetric cortical arteries, after preoperative arteriography, is described and 3 cases of cerebral angiomas presented with striking symptomatic improvement after embolization. Postoperative angiography in one case showed considerable diminution in the size of the angioma.

[Complementary procedures to the Sjoqvist operation in cancerous cervico-facial pain]

The trigeminal spinal tractotomy of Sjoqvist can be enlarged and give a very good result on cancer pain of face and throat. When pain is also cervical, it is usefull to associate with the Sjoqvist operation two important procedures: 1 degree--Instead of a simple posterior cervical radicotomy it seems best to practise a selective posterior radicellotomy. This technic has the advantage to preserve the sensory proprioceptive capacity of the superior limb, while being perform even until C6 and C7 roots. Also in case of recurrence of cervico brachial pain, it remains easy to apply a posterior spinal stimulation. 2--The spinal nerve has not only a motor function but also a sensory one. The sensory fibers travelling through small anastomosis between "LARUELLE Ganglion" and cervical roots must be separated to obtain a more complete analgesia.

[Prognostic elements at early stapes of severe spinal cord injuries (value of pain sensitivity]

The prognosis in serious spinal cord injury remains difficult. The neurologist has a large number of elements at his disposal, but their reliability is uncertain. Clinical information, experimental work and recent data on medullar vascularization makes it possible to isolate diagramatically in the spinal cord a medium layer which contains the pyramidal and spino-thalamic tracts. The neighbourhood of these two fasciculi confers them a similar vulnerability to severe injury. Thus when an injured tetraplegic or paraplegic patient recovers his sensitivity to pain, he finally must recover his motor function and on the contrary, the recovery of motility is impossible without a return of pain sens. Clinical observation is in consequence of major importance as it shows that the recovery of sensitivity to pain, in the case of a patient with a serious spinal cord injury, is an argument for a favourable prognosis, whereas the recovery of an isolated tact perception does not in itself makes it possible to hope for eventual recovery of motor power.

[Results of selective posterior radiculetomy at the lumbar and cervical level]

At the light of authors' present experience, radicletomy appears as an excellent antalgic operative procedure in the case of roots with high functional risk (brachial plexus and lumbar plexus). In the absence of any motor deficiency or ataxia, it appears that radicletomy is of help in the cure of severe hypertonies of the extremities (sequelae of cerebral stem contusions). Conversely, in the spastic sequelae of hemi- or paraparesias, lumbar-sacral posterior selective radicotomy is a sure procedure that procures results nearly super-imposable to radicletomy with an appreciable gain in time. At last, for what concerns the motor involvements of the upper extremity ending in spasticity, selective radicletomy recovers its rights and has to be preferred to S.P.R. The indications may be summarized as follows: -- At the level of the lower extremities: in the case of paraparetic sequelae or of sequelae due to spastic paraplegia, a S.P.R. has to be performed; for what concerns antalgic surgery, in the absence of motor deficiency, the best indication is radicletomy. -- At the level of the upper extremities: in the case of dystonic sequeale of the cerebral stem, spastic pain bound with hemiplegia or with carcinoma etc. (herpes zoster..), radicletomy constitutes the ideal surgical procedure.