Acute amphetamine abuse. Problems during general anaesthesia for neurosurgery

A case of unsuspected acute amphetamine abuse by a 22-year-old girl which led to serious intracranial hypertension during anaesthesia for a neurosurgical procedure is described. It was difficult to maintained anaesthesia with an intermittent positive-pressure ventilation technique using muscle relaxants, N2O and O2 and supplements of fentanyl despite large doses of pancuronium and fentanyl. The differing effects of chronic and acute amphetamine dosage on anaesthetic requirements are reviewed.

Early effects of thyroidectomy and triiodothyronine administration on rat-liver mitochondria

This work was undertaken to study the action exerted by thyroid hormones on mitochondria. By day 6 after thyroidectomy, the respective activities of two inner-membrane enzymes--succinate and beta-hydroxybutyrate cytochrome c reductases--had already dropped by 32 and 50%, whereas, in the outer membrane, the activity of rotenone-insensitive NADH-cytochrome c reductase did not change significantly. The decrease in the activity of the inner-membrane enzymes closely followed the disappearance of T3 and T4 from serum. 10 h after administration of 25 micrograms/100 g T3 to thyroidectomized rats, the activity of succinate and beta-hydroxybutyrate cytochrome c reductases and the oxygen consumption rate with succinate or beta-hydroxybutyrate were significantly increased, while, in the outer membrane, the activity of monoamine oxidase and rotenone-insensitive NADH-cytochrome c reductase remained unchanged. In the thyroidectomized rat, L-[3H]leucine incorporation in vivo is diminished in all the liver mitochondrial proteins, and especially in two constituents of MW 19 000 and 28 000. The radioactivity of these two components is also decreased in the normal rat treated with chloramphenicol, a specific inhibitor of mitochondrial protein synthesis. L-[14C]leucine incorporation in isolated liver mitochondria was significantly increased in the thyroidectomized rat, 10 h after T3 treatment. Thus, thyroid hormones have an early and preferential action on the mitochondrial protein synthesizing system and on the inner-membrane enzyme activities.

Accidental intra-arterial injection of papaveretum during anaesthesia

The circulatory depressant action of papaveretum was demonstrated when the drug was injected accidentally into the radial artery during neuroanaesthesia in the upright (sitting) position. The signs of air embolism were mimicked. The condition reponded promptly to a vasopressor given intravenously. There were no harmful sequelae to the patient's hand.

[Fine-structure changes in Toxoplasma gondii trophozoites after deep-freezing with dimethyl sulphoxide (author's transl)]

The changes observed in trophozoites of Toxoplasma gondii after deep-freeze preservation were examined by electron microscopy. Toxoplasmas (strain BK) from peritoneal exudate of infected NMRI mice were supended in Ringer's solution, deep-frozen in liquid nitrogen with 5% dimethylsulphoxide (DMSO), and compared after thawing with control samples with and without the addition of DMSO. Slight structural changes such as widening of endoplasmic reticulum, formation of fissures in the cytoplasm, and loosening of chromatin were only observed in some of the free toxoplasmas of the DMSO control. Among the deep-frozen parasites, about 1/5 of the free stages showed no or only slight morphological changes. In contrast to this, almost all intracellular forms found in macrophages showed lesions. The most remarkable change was a partial destruction of the inner cell membrane complex. The outflow of ribosome-containing protoplasm with ballon-like swelling of the outer elementary membrane was observed as a consequence of this frequent lesion. The outflow of protoplasm induced a drastic decrease in the electronic density of the whole cytoplasm. Other characteristic degenerative signs were vacuolation of cytoplasm up to formation of great optically empty spaces, widening of the perinuclear space, swelling of mitochondria, disintegration of rhoptria, micronemata, and Golgi zone, coarse-plaque loosening, and displacement of electron-dense areas of the nucleus up to disintegration with maintenance of the karyoplasm. In some almost completely disintegrated trophozoites, enlarged mitochondria with remarkable electronic density were observed. Apart from the cell membrane, the conoid was the longest-persisting organelle. The alterations observed after deep-freezing permit the conclusion that the free cells, which were only slightly impaired or not at all, remained infective.

[Serum iodothyronine concentrations and properties of mitochondria phosphorylative oxidations in old rats]

Serum concentrations of T4 and T3 in 2 year-old Rats were decreased by about 30% compared to 2 month-old animals, but rT3 was similar. Activities of old Rats' liver mitochondria were near those of young thyroidectomized animals. Low circulating T3 partly explains metabolic changes observed during senescence.

The two human trypsinogens: catalytic properties of the corresponding trypsins

The catalytic properties of the two human trypsins obtained from purified trypsinogens have been studied. The catalytic rate constant kcat and the pK of the ionisable residue implicated in the active site have been determined with Bz-Arg-OEt. The hydrolysis of Tos-Arg-OMe by human trypsins does not follow the simple Michaelis-Menten scheme and indicates a difference in the conformational flexibility of the active site-regions of the two enzymes. Both enzyme are readily autolyzed and calcium ion plays a fundamental role in stabilizing trypsin activity. However trypsin 2 self-digests more rapidly than trypsin 1. These results are a prerequisite to the elucidation of the fate of pancreatic enzymes in human digestive tract.

[Invasion of erythrocytes by toxoplasma gondii (author's transl)]

The in vitro-invasion of mouse erythrocytes by Toxoplasma gondii could be detected and analysed by electron microscopy. The sequence of events observed during erythrocyte invasion led to the assumption of an actively penetrating parasite into the non-phagocytic host cell.

[Binding of 3,3',5'-triiodo-L-thyronine (rT3) to human serum proteins]

The rT3-binding and human serum proteins was directly studied with tracer doses of radioactive rT3. Polyacrylamide gel electrophoresis showed 125I-rT3 added to human serum was distributed among two proteins: albumin (carrying 57% of tracer rT3) and TBPA )22%). No binding was observed to TBG, protein binding T4.

Structural changes on Entamoeba histolytica trophozoites after cryopreservation in liquid nitrogen

Trophozoites of Entamoeba histolytica cultures which had been deep-frozen in the presence of 5% DMSO, along with untreated cells and cells treated with DMSO (5%), were examined for fine-structural changes. After deep-freezing in liquid nitrogen only a few amoebae exhibited normal nuclear and cytoplasmic structure. One frequently observed but unspecific finding pertaining to recovered cells is the separation of the cytoplasm into large vacuolated (coarse-granular) and electron-optically fine-granular (hyaline) zones. The glycogen which normally lies in the cytoplasm is always eluted. In many cases numerous short RNP helices are scattered unevenly in the vesicular plasma, but they are also found in larger masses adjacent to the membranes of still intact and already damaged nuclei. Moderately damaged nuclei have a poorly folded membrane and their chromatin is markedly denatured. More heavily damaged nuclei have a membrane which has partly fibrillated or ruptured and then formed conspicuous folds, where the nuclear membrane has ruptured nucleoplasmic remnants of chromatin and button-like bodies appear to pour into the surrounding cytoplasm. The final destruction of the cell is marked by coalescing autolytic zones, first in the vacuolated and later in the fine-granular cytoplasm. Finally only remnants of the nuclear membrane and of the membranes of numerous vacuoles remain. It is assumed that most of the changes in the cytoplasm are of a secondary nature and are caused by the early functional disturbance of the nucleus.

The two triiodothyronines (T3 and rT3). Thyroid biosynthesis of T3 and rT3 and peripheral metabolism of thyroxine (author's transl)

Thirty per cent of the iodine in thyroglobulin is present as iodothyronines. L-thyroxine (T4) represents 90-95% of hormonal iodine, 3,5,3'-triodo-L-thyronine (T3) contains at the most two per cent of it, 3,3'5'-triodo-L-thyronine (rT3) even less, as well as traces of 3,3'-diodo-L-thyronine. The plasma concentration of T4 is about 8 microgram per 100 ml, in the case of T3 it is 120 ng and 25 ng for rT3. The cell nucleus preferentially binds T3 and rT3 and there are also some specific mitochondrial proteins which possess a high affinity for T3. L-thyroxine is dehalogenated peripherically to T3, to take care of most of the requirements in T3. The enrichment of the plasma in rT3 has been shown to occur under various experimental and pathological conditoins. The blood level of T3 varies in inverse ratio to the level of rT3 and it shows that the peripheral formation of one is compensated for by the other. The excess of the prehormone T4 is metabolised as 3,5,3',5'-tetraiodothyroacetic acid (TetrAc); its level in the blood varies in the same way as the level of T3, in particular it decreases during starvation.

Human pancreatic lipase: a glycoprotein

Human lipase has been purified from pancreatic juice. The protein has a molecular weight of 48 000 and an N-terminal residue of lysine. It has been characterized as a glycoprotein containing 4.7 mol of glucosamine, 2.8 mol of mannose, 2.9 mol of fucose, 3.0 mol. of galactose and 1.1 mol of glucose per mol of protein. Two isolipases have been separated by polyacrylamide gel electrophoresis. Their isoelectric points are 5.80 and 5.85, respectively and both are glycoproteins. Immunological cross reactions have been obtained between human lipase and other mammalian lipases (porcine, bovine, ovine, canine and rat).

Nonparallel courses of intrapancreatic levels of exportable enzymes after a fatty meal

Stimulation of pancreatic secretion by a fatty meal resulted in a nonparallel time-course of intrapancreatic amylase, lipase, trypsinogen, and chymotrypsinogen levels. Concomitant variations in the rate of pancreatic protein biosynthesis are observed. Those results support the hypothesis that nonparallelism in exportable enzyme levels is a consequence of a nonparallel regulation by the stimulus of the individual rates of enzyme biosynthesis.

Action of intracellular proteinases on mitochondrial translation products of Neurospora crassa Schizosaccharomyces pombe

Gel electrophoretic analysis of mitochondrial membranes from Neurospora crassa shows the presence of a polypeptide fraction with apparent molecular weights of 7000 - 1200, which is synthesized on mitochondrial ribosomes. This fraction comprises between 10 and 50% of total mitochondrial translation products. Evidence is presented that the major part of this fraction is derived from components with higher apparent molecular weights by proteolytic activity. The proteolytic activity is located in vesicles which are co-isolated with mitochondria upon differential centrifugation. The activity is strongly enhanced by application of detergents such as sodium dodecylsulfate and Triton. Proteins synthesized on mitochondrial as well as cytoplasmic ribosomes are subject to proteolytic breakdown. This proteolysis can be blocked by addition of inhibitors such as diisopropylfluorphosphate to isolated mitochondria. Similar observations were made with Schizosaccharomyces pombe. In Neurospora, the amount of mitochondrial translation products with apparent molecular weights of less than 12000 is low in mitochondria from cells treated with cycloheximide for 1 h and high in mitochondria from cells treated with cycloheximide for 5 min. This observation is explained by the finding that proteinase activity in mitochondrial preparations decreases exponentially with a t1/2 of 20 min during preincubation of cells with cycloheximide. Procedures are described to remove or block contaminating proteinase activity. The results appear to be relevant for the interpretation of many data obtained from experiments in which this puzzling kind of artifact has not been sufficiently considered.

[Effects of thyroidectomy of the rat on the structure and functions of skeletal muscle mitochondria]

Mitochondria used in the present study were isolated from skeletal muscle of normal and thyroidectomized rats. The preparations were controlled by electron microscopy. It was not possible to find any morphological change induced by thyroidectomy, nevertheless, some difference appeared in the cytochrome contents which were slightly decreased. Oxygen consumption rates of thyroidectomized rat mitochondria were decreased when the particles were maintained in states 3 and 4 in the presence of various substrates, but the P/O ratios were not modified. The activities of mitochondrial enzymes were in general slightly affected by thyroidectomy except for glycerol-1-phosphate cytochrome c reductase and NADH rotenone sensitive cytochrome c reductase which were decreased and for glutamate dehydrogenase activity which was increased. The tRNA nucleotidyltransferase activity found in the mitochondrial matrix was not influenced by the absence of thyroid secretion. Normal rat muscle mitochondria incorporate 14C-leucine with an artificial ATP-generating system or with a respiratory substrate. The amino acid incorporation was decreased by thyroidectomy. Muscle mitochondria analyzed by polyacrylamide gel electrophoresis contained more than 30 protein components with MW ranging from 10.000 to 135.000. Thyroidectomy lowered the amount of a fraction of about 54.000 MW. It is not impossible that all the data observed in the absence of thyroid secretion are in relation with changes induced in the mitochondrial genome as previously shown in mitochondria isolated from liver or thyroidectomized rats.

Isolation and characterization of a mitochondrially synthesized polypeptide from Neurospora crassa cni-1 mutant

A polypeptide with a molecular weight of 8 500 (HP 8 500) was isolated from the mitochondrial membrane of the nuclear mutant cni-1 of Neurospora crassa. This mutant is characterized by a cyanide-insensitive respiration and by a deficiency in the cytochromes aa3 and b. The polypeptide is synthesized on mitochondrial ribosomes. It has an extremely hydrophobic character; it is insoluble in aqueous media in the absence of sodium dodecylsulfate and is soluble in acid chloroform/methanol. It lacks histidine. The polar amino acids lysine, arginine, aspartic acid, glutamic acid, serine and threonine make up only 25% of the total amino acids on a mole-percent basis. The N-terminal amino acid is tyrosine. The possible function of this polypeptide in the mitochondrial membrane is discussed.

[Fibrillar and tubular fine structures in the cytoplasm of Entamoeba histolytica (author's transl)]

The electron-microscopical study of conventional fixed and contrasted Entamoeba histolytica-trophozoites from Diamonds monoxenic TTY-medium revealed "thick fibrils" in the vesicular cytoplasm of the parasites. They are 9-14 nm in diameter and are therefore considered to be myosin-like filaments, that are spread mainly in the tail or the uroid of the moving ameba. No association with microfilaments (MF) or other organelles could be observed. During the same investigation microtubules (MT) of variable length are described having a diameter of 35 nm, surrounded by a 19-25 nm wide capsule. They are distributed singly or in bundles with a maximal diameter of 350 nm. Some of the MT were coiled up to a helical shape.

[Influence of thyroid status on the electrophoretic pattern of rat liver mitochondrial proteins]

Liver mitochondria were isolated from normal and thyroidectomized rats and their protein components analyzed by polyacrylamide gel electrophoresis. In whole mitochondria 35 protein fractions with MW ranging from 10,000 to 135,000 were characterized. In the absence of thyroid hormone secretion, the amount of a MW 54,000 fraction was always decreased. Injection of small doses of 3,5,3'-triiodo-L-thyronine to the thyroidectomized animal restored the quantity of that protein fraction to normal. Isolated outer mitochondrial membranes showed the presence of 20 protein fractions. These fractions revealed no change after thyroidectomy. The mitoplast, which contained 35 fractions, exhibited a decrease of the MW 54,000 component in thyroidectomized rats. The mitoplast was separated into several fractions. Water soluble matrix proteins presented molecular weights ranging between 40,000 and 55,000. Proteins, which were slightly bound to the inner mitochondrial membrane and could be extracted by KCl, presented molecular weights between 25,000 and 45,000. Structural proteins showed a principal specific component of MW equals 23,000. Electrophoretic patterns obtained with these submitochondrial fractions were similar in normal and thyroidectomized animals. The mitoplast fraction which contained the insoluble cytochromes (a, a3, b, c1) was isolated ; its principal constituent, of MW 54,000 was significantly decreased after thyroidectomy. Thus, the lack of thyroid hormone secretion lowered the level of a protein constituent bound to the inner membrane of liver mitochondria. The synthesis of this constituent could be controlled by mitochondrial nucleic acids.