Summary: Extracellular concentrations of ascorbic acid, glutathione, cysteine, uric acid, tyrosine, and tryptophan were monitored using intracerebral microdialysis in the left frontoparietal cortex of spontaneous hypertensive rats before, and for 3 h after, either focal ischemia [left middle cerebral artery occlusion (MCAO)] or sham oper ation. The size of the ischemic area and the position of the microdialysis probe were checked using the enzyme his totopochemical acid phosphatase reaction. The probe was always located in the cortex inside the stained area. Ascorbic acid levels rose immediately after MCAO and remained at about 12-fold for 3 h. There was a transient Microdialysis (Tossman and V ngerstedt, 1986; Benveniste and Huttemeier, 1990) provides a mini mally invasive method for continuously monitoring changes in concentrations of low-molecular-weight substances in the extracellular (EC) fluid of various organs. It has been used to study cerebral ischemia in the rat, measurements being made mainly in the striatum, one of the areas most susceptible to isch emic damage. Changes have been found in this re gion at the onset of cerebral ischemia in the EC concentrations of various parameters, e. g. , ascor bic acid (Hillered et aI. , 1988), lactate (Hillered et aI., 1989), purine metabolites (Hagberg et aI. , 1987),

Modification dependent restriction endonucleases (MDREs) often have separate catalytic and modification dependent domains. We systematically looked for previously uncharacterized fusion proteins featuring a PUA or DUF3427 domain and HNH or PD-(D/E)XK catalytic domain. The enzymes were clustered by similarity of their putative modification sensing domains into several groups. The TspA15I (VcaM4I, CmeDI), ScoA3IV (MsiJI, VcaCI) and YenY4I groups, all featuring a PUA superfamily domain, preferentially cleaved DNA containing 5-methylcytosine or 5-hydroxymethylcytosine. ScoA3V, also featuring a PUA superfamily domain, but of a different clade, exhibited 6-methyladenine stimulated nicking activity. With few exceptions, ORFs for PUA-superfamily domain containing endonucleases were not close to DNA methyltransferase ORFs, strongly supporting modification dependent activity of the endonucleases. DUF3427 domain containing fusion proteins had very little or no endonuclease activity, despite the presence of a putative PD-(D/E)XK catalytic domain. However, their expression potently restricted phage T4gt in Escherichia coli cells. In contrast to the ORFs for PUA domain containing endonucleases, the ORFs for DUF3427 fusion proteins were frequently found in defense islands, often also featuring DNA methyltransferases.

A review is made of the current management strategies of abscesses in basal ganglia and thalamus, based on a review of the literature and three of our own cases. Clinical picture, aetiology, diagnostic, surgical treatment and outcome are discussed. Stereotactic abscess puncture in combination with temporary drainage and rinsing of the abscess cavity in combination with systemic medication of antibiotics has become the management of choice with satisfactory results.

Abstract. Despite the high incidence of acute metabolic acidosis, there are no reliable human data to enable physicians to accurately diagnose this disorder. In addition, there is uncertainty about the direction and magnitude of plasma potassium changes in acute metabolic acidosis. The systemic and renal acid-base, electrolyte, and endocrine response to acute acid loads (imposed by three timed NH 4 Cl infusions into the duodenum, 0.9 mmol of NH 4 Cl per kg of body weight over 30 min each) was characterized in six healthy male subjects in whom a metabolic steady-state had been established. Arterialized blood CO 2 tension decreased by 0.85 mmHg per mmol/L decrease in plasma bicarbonate concentration and blood hydrogen ion concentration increased by 0.45 nmol/L per mmol/L decrease in plasma bicarbonate concentration. Plasma potassium did not change significantly (ϩ0.02 Ϯ 0.02 mmol/L per mmol decrease in plasma bicarbonate concentration). Plasma insulin increased and plasma glucagon levels decreased in acute metabolic acidosis, while catecholamines and aldosterone were not affected significantly. These data provide the first diagnostic criteria for the diagnosis of acute metabolic acidosis in humans. The finding of a hyperinsulinemic response in acute metabolic acidosis suggests that an insulin response counterregulates any acidemia-induced cellular potassium efflux, resulting in stable plasma potassium concentrations.

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