Repetitive skill deterioration with fast and exercise-lowered blood glucose

Using a computerized system for measurement of the variability of force exerted at 26 points in each pedal revolution during the repetitive habituated task of cycling, healthy adult males 6 times performed for 20 minutes, either (a) 3 hours after a meal (fasting) or when so fasted and then fed glucose (b) immediately before, or (c) 30 minutes before performance. Both light and moderate workloads were used. As expected, blood glucose concentrations fell modestly below basal with exercise under (a) or (c) but not under (b). ANOVA of force mean and variability statistics significantly contrasted the 3 treatments, and 2 linear functions from multivariate analysis showed (a) and (c) to be significantly different from (b). These two treatments depressing blood glucose were more variable in force applied, with altered pattern of average forces, especially for points in the task where changes occurred in the force/time relationship. These points may use more immediate feedback correction. Such deterioration of movement control has significant applied implications and invites study of its neural aetiology.

Sporulation competence in Physarum polycephalum CL and the requirement for DNA replication and mitosis

The optimum conditions for sporulation and the requirements for mitosis and DNA replication during the onset of the process have been investigated in plasmodia of the CL strain of Physarum polycephalum. A 72 h period of starvation was necessary before a plasmodium became competent to sporulate on exposure to light. The plasmodium became irreversibly committed to sporulation 4 to 5 h after illumination. The commitment point was related to the time of illumination rather than the duration of starvation. Three periods of DNA synthesis were detected during the initial 24 h of starvation, but in an asporogenous derivative of the CL strain only the first two periods were detected. Inhibition of mitosis with nocodazole or of DNA synthesis with hydroxyurea prevented sporulation. Escape of plasmodia from hydroxyurea inhibition of sporulation coincided with the last detectable period of DNA synthesis, but escape from nocodazole inhibition of sporulation occurred 25 to 30 h later.

[Amyloidosis and polycythemia vera (author's transl)]

The authors report a case of systemic amyloidosis with predominantly hepatic, splenic and renal deposits and polycythemia vera with secondary myelofibrosis. The course of both diseases during a 9-year-follow-up and the late appearance of a monoclonal IgM lead the authors to examine a possible relationship between the two diseases.

Glucose starvation alters lipid-linked oligosaccharide biosynthesis in Chinese hamster ovary cells

The effect of glucose deprivation on the synthesis of lipid-linked oligosaccharides by Chinese hamster ovary cells has been studied. When these cells are placed in serum-free Dulbecco's minimal essential medium devoid of glucose, there is a rapid cessation of the synthesis of the usual Glc3Man9GlcNAc2 lipid-linked oligosaccharide and the accumulation of a smaller species with the composition Man9GlcNAc2. This latter compound is the glucosylated and transferred to protein where it is subsequently processed. These findings demonstrate that Chinese hamster ovary cells utilize an alternate glycosylation pathway when deprived of glucose.

Ultrastructure and function of cysts from human adult polycystic kidneys

Twenty cysts from five patients with adult polycystic kidney disease were evaluated morphologically by electron microscopy and functionally by cyst fluid chemical analysis in order to correlate the structure with the function of the cyst wall. Thirteen proximal cysts, as defined by cyst fluid/serum sodium ratios of 0.8 to 1.2, were lined by epithelial cells with open or short closed apical junctions that appeared permeable to lanthanum. In contrast, seven distal cysts, as defined by cyst fluid/serum sodium ratios of less than 0.4, were lined by epithelial cells with long closed apical junctions that appeared impermeable to lanthanum. Cell organelles showed no distinction between proximal and distal cysts. Cyst basement membranes appeared abnormal, but there was no consistent pattern. The fluid of proximal cysts contained lower creatinine, potassium, and hydrogen ion, and higher chloride concentrations than did the distal cysts. These studies provide morphologic and chemical evidence consistent with te view that cysts originate from nephrons. Moreover, the maintenance of the epithelial lining and transmembrane solute gradients over many years extending up to and beyond the development of renal insufficiency suggests that the cysts function as nephronsthrughout the life of the patient.

Structure of the high mannose oligosaccharides of a human IgM myeloma protein. I. The major oligosaccharides of the two high mannose glycopeptides

The structures of the predominant high mannose oligosaccharides present in a human IgM myeloma protein (Patient Wa) have been determined. The IgM glycopeptides, produced by pronase digestion, were fractionated on DEAE-cellulonalysis shows that glycopeptide I contains Asn, Pro, Ala, Thr, and His and glycopeptide II contains Asn, Val, and Ser, which are the same amino acids found in the sequences around Asn 402 and Asn 563 respectively, to which high mannose oligosaccharides are attached in IgM (Patient Ou) (Putnman, F.W., Florent, G., Paul, C., Shinoda, T., and Shimizu, A. (1973) Science 182, 287-290). The high mannose glycopeptides in IgM (Wa) exhibit heterogeneity in the oligosaccharide portion. Structural analysis of the major oligosaccharides indicates that the simplest structure is: (see article of journal). The larger oligosaccharides present have additional mannose residues linked alpha 1 yields 2 to terminal mannose residues in the above structure. Glycopeptide I contains primarily Man5 and Man6 species, while glycopeptide II contains Man6 and Man8 species. The two Man6 oligosaccharides have different branching patterns.

Structure of the high mannose oligosaccharides of a human IgM myeloma protein. II. The minor oligosaccharides of high mannose glycopeptide

The high mannose glycopeptide I from IgM (Patient Wa) contains, in addition to the two major oligosaccharides described earlier (Chapman, A., and Kornfeld, R. (1979) J. Biol Chem. 254, 816-823), four minor oligosaccharides. After release from glycopeptide I by endo-beta-N-acetylglucosaminidase Cu and reduction with NaBH4, all four oligosaccharides have been shown to have the basic structure: (see article of journal). Oligosaccharide IA-1 (Man9GlcitolNAc) has additional alpha1,2-linked mannose residues attached to positions a and b, and the sequence Man alpha1,2 yields to Man alpha1,2 yields to attached at position c. Oligosaccharide IA-2 (Man8GlcitolNAc) has additional alpha1,2-linked mannose residues attached to positions a, b, and c. Oligosaccharide IA-3 (Man7GlcitolNAc) has additional alpha1,2-linked mannose residues at positions b and c. In contrast, oligosaccharide IA-4 has a single N-acetyglucosamine residue beta1,2-linked to the mannose at position c. Oligosaccharides IA-1, -2 and -3 are thought to represent "processing" intermediates that are precursors of the major Man6 and Man5 oligosaccharides of glycopeptide I. IA-4 may arise from the Man5 oligosaccharide by the action of UDP-GlcNAc:glycoprotein N-acetylglucosaminyl-transferase, which catalyzes the first reaction leading to complex oligosaccharide synthesis.

Effect of high dose d-l propranolol on the renin-angiotensin system in glycerol induced acute renal failure in rat

Stimulation of the renin-angiotensin system has been implicated in the pathogenesis of post-ischemic and nephrotoxic acute renal failure. This study was designed to determine the effect of d-l propranolol in glycerol induced acute renal failure in rats. 50% glycerol administered alone, induced a significant rise in blood urea and plasma renin concentration but no significant change in renal renin concentration. When administered with d-l propranolol (10 mg/kg body weight in 5 subcutaneous injections), mean blood urea, plasma renin and renal renin concentrations were not significantly different from the preceding group. Propranolol alone, administered in the same fashion, unexpectedly induced a rise in plasma renin concentration (p less than 0.05) while blood urea and renal renin concentrations were unchanged. Considering the unusually high dose of propranolol used, a second protocol was devised to compare the effects of d-l propranolol, in doses of 10 mg/kg and 1 mg/kg. Plasma renin concentration rose after high dose propranolol, but decreased, although not significantly, after administration of 1 mg/kg. Renal renin concentration was unchanged. High dose d-l propranolol, does not protect rats against glycerol induced acute renal failure. Contrarily to the usual 1 mg/kg dose, it was found surprisingly to increase renin release.

Increased glomerular filtration rate in patients with major burns and its effect on the pharmacokinetics of tobramycin

The clearance of endogenous creatinine in 20 burned patients, measured between the fourth and the 35th post-burn day, was a mean (+/- S.D.) of 172.1 p 48.4 ml per minute per 1.73 m2; in eight normal subjects the mean value was 125.4 g- 10.4 (P less than 0.02). Thirteen patients had values more than 2 S.D. above the normal mean. We confirmed this rise in glomerular filtration rate by measuring inulin or iothalamate clearance in nine patients. The pharmacokinetics of tobramycin were studied in 11 of the 20 patients and in eight normal subjects receiving continuous intravenous infusions of the drug. An inverse correlation was found between plasma half-life of the drug and creatinine clearance (r = 0.68, P less than 0.01). Increased creatinine clearances and shortened half-life of tobramycin occurred mainly in younger patients. Glomerular filtration rates in burned patients may rise to very high values and can be validly measured by creatinine clearance. The plasma half-lives of drugs with predominantly urinary excretion may decrease in patients with burns.

[Multiple injuries and multiple methods of resuscitation]

The aim of treatment in the trauma patient is the surgical repair of all traumatic lesions in as short a time as possible, using standard techniques and at the same time if possible. Such surgical intervention may rarely be essential for survival (internal haemorrhage, extradural haematoma), but is almost always an essential factor in the functional and aesthetic result obtained. Thus everything should be combined to fulfill this objective. Picking up of the injured, resuscitation at the site of the accidentation and the quality and appropriate orientation of transport are of obvious importance from this standpoint and it is easy to understand that first efforts must lie here.

Partial characterization of a temperature-sensitive mutation affecting acetyl coenzyme A carboxylase in Escherichia coli K-12

A temperature-sensitive mutation in Escherichia coli K-12 was shown to affect acetyl coenzyme A carboxylase and to map at min 63. This site is designated fabE.

Late streptokinase therapy in thrombotic microangiopathy: a case study

A 42 year woman presented with malignant hypertension, anuria and hemolytic anemia with schistocytosis. The diagnosis of thrombotic microangiopathy was confirmed by early renal biopsy. Purely symptomatic treatment (peritoneal dialysis and hypotensive drugs) was supplemented by administration of heparin and Dipyridamole. Gastro-intestinal bleeding prevented early thrombolytic therapy. Microangiopathic anemia rapidly disappeared but anuria persisted. Three months later a second renal biopsy showed persistence of active lesions and absence of irreversible parenchymal damage. Streptokinase treatment was then instituted and followed by a rapid return of urinary output. Hemodialysis was stopped and renal function continued to improve over the following months. Two years later the patient remains well despite persistence of hypertension difficult to control. Creatinine clearance is stable at 20 ml/min. This observation suggests that late thrombolytic therapy may be effective in patients with thrombotic microangiopathy when histological findings do not indicate extensive irreversible lesions.

Abnormal fatty acid composition and human atherosclerosis

Eighty patients with aorto-iliac / femoro-popliteal atherosclerosis were collected to examine in detail their plasma cholesteryl ester fatty acid compositions and to compare them with the incidence of ischaemic heart disease through a 4-year follow-up. Various other biochemical and rheological parameters were also measured to see if these might explain any association between the abnormal fatty acid pattern and ischaemic heart disease.

The abnormal fatty acid pattern was specifically and generally similar to that found in essential fatty acid (EFA) deficient animals and children as shown by the increase of the specific trienoic acid (C.20: 3ω9) by reduced linoleic acid concentrations, and by an increase of C.18 and C.16 monoenoic acids (oleic and palmitoleic), but not of their corresponding saturated forms, stearic and palmitic. The results suggest that the abnormal fatty acid composition resulted from an increased synthesis of monoenoic acids and monounsaturase activity, coupled with a relative inadequacy of linoleic acid.

The patients with a reduced concentration of linoleic acid (<35%) subsequently had a higher incidence of myocardial infarction. No significant correlations were found between the fatty acid concentration and various other biochemical or rheological parameters except marginally between linoleic acid and platelet adhesiveness. Only the linoleic acid concentration distinguished between the patients with and without myocardial infarction.

A marked inverse correlation was found, however, between the monoenoic and linoleic acid concentration, without parallel changes in other fatty acids. It seems that as in animals, a balance exists between EFA and monoenoic pathways which are known to compete for the same desaturase systems and acyl sites. It appears that human EFA requirements and effects need to be considered not only by their intake and metabolism, but also through individual factors which vary the monoenoic concentrations and monounsaturase activity. Since these factors include several currently associated with human atherosclerosis the question arises of whether the EFA-monoenoic balance is one link between them and the pathology of the arterial occlusions and myocardial infarction.