Gene organization and primary structure of human hormone-sensitive lipase: possible significance of a sequence homology with a lipase of Moraxella TA144, an antarctic bacterium

The human hormone-sensitive lipase (HSL) gene encodes a 786-aa polypeptide (85.5 kDa). It is composed of nine exons spanning approximately 11 kb, with exons 2-5 clustered in a 1.1-kb region. The putative catalytic site (Ser423) and a possible lipid-binding region in the C-terminal part are encoded by exons 6 and 9, respectively. Exon 8 encodes the phosphorylation site (Ser551) that controls cAMP-mediated activity and a second site (Ser553) that is phosphorylated by 5'-AMP-activated protein kinase. Human HSL showed 83% identity with the rat enzyme and contained a 12-aa deletion immediately upstream of the phosphorylation sites with an unknown effect on the activity control. Besides the catalytic site motif (Gly-Xaa-Ser-Xaa-Gly) found in most lipases, HSL shows no homology with other known lipases or proteins, except for a recently reported unexpected homology between the region surrounding its catalytic site and that of the lipase 2 of Moraxella TA144, an antarctic psychrotrophic bacterium. The gene of lipase 2, which catalyses lipolysis below 4 degrees C, was absent in the genomic DNA of five other Moraxella strains living at 37 degrees C. The lipase 2-like sequence in HSL may reflect an evolutionarily conserved cold adaptability that might be of critical survival value when low-temperature-mobilized endogenous lipids are the primary energy source (e.g., in poikilotherms or hibernators). The finding that HSL at 10 degrees C retained 3- to 5-fold more of its 37 degrees C catalytic activity than lipoprotein lipase or carboxyl ester lipase is consistent with this hypothesis.

99mTc-DTPA aerosol for same-day post-perfusion ventilation imaging: results of a multicentre study

A multicentre study was performed in an attempt to evaluate a submicronic technetium-99m diethylene triamine penta-acetic acid aerosol generated by a newly developed delivery system, the aerosol production equipment (APE nebulizer), for same-day post-perfusion ventilation imaging in patients with clinically suspected pulmonary embolism. Quantitative comparison between the DTPA aerosol and krypton gas demonstrated a close correlation with respect to regional pulmonary distribution of activity and peripheral lung penetration (n = 14, r = 0.94, P < 0.001 and r = 0.75, P < 0.0025, respectively). In 169 consecutive patients, DTPA aerosol images performed immediately following perfusion (inhalation scan I) were compared to those carried out on the next day (inhalation scan II) with respect to image quality and assessment of perfusion-ventilation matches or mismatches. Agreement between inhalation scans I and II with respect to perfusion defects matched or mismatched to ventilation was found in 166/169 (98%) studies. The image quality of inhalation scan I was equal to that of scan II in 72%; inhalation scan I was superior in 11% of cases, while scan II was superior in 17%. This submicronic 99mTc-labelled DTPA aerosol is well suited for fast same-day post-perfusion ventilation imaging in patients with clinical suspicion of pulmonary embolism.

Ovarian cancer staging: does it require a gynecologic oncologist?

Forty-seven patients with presumed Stages I-II invasive ovarian epithelial carcinoma were treated with intravenous 50 mg/m2 cis-platinum, for 2-18 cycles (median, 9), 50 mg/m2 doxorubicin for 2-14 cycles (median, 9), and/or 600 mg/m2 cyclophosphamide for 2-14 cycles (median, 6) after surgical staging by a gynecologic oncologist or a nononcologic surgeon. Mean follow-up is 6.8 years. Cumulative 5-year actuarial survival is 73 +/- 6%; 75 +/- 12% for Stage I and 71 +/- 8% for Stage II disease. When screened for poor prognosticators, only the specialty of the operating surgeon was identified (P < 0.05). Five-year actuarial survival and disease-free survival, respectively, for Stages I-II patients surgically staged by a gynecologic oncologist were 83 +/- 7% and 76 +/- 8%, compared to 59 +/- 11% (P < 0.05) and 39 +/- 11% (P < 0.03) for the group operated upon by a nononcologist.

Genetic analysis of the gyrase A-like domain of DNA topoisomerase II of Saccharomyces cerevisiae

We have undertaken a genetic analysis of heat-sensitive and cold-sensitive mutations in TOP2, the gene encoding yeast DNA topoisomerase II. Deletion mapping was used to localize 14 heat-sensitive and four cold-sensitive top2 mutations created by a method biased toward mutations in the 3' two-thirds of the gene. The mutations all appear to be located in the region of DNA topoisomerase II that shows homology to the "A" subunit of bacterial DNA gyrase. The heat-sensitive mutations and one cold-sensitive mutation lie in the center of the gene near the sequence that encodes the active site tyrosine. The three other cold-sensitive mutations map farther toward the 3' end of the gene. The cold-sensitive mutations exhibit intragenic complementation, and the complementation groups correspond to the physical map. We sequenced nine top2 mutations and found that the mutations are usually single missense mutations, frequently involve proline, and affect conserved regions of the protein. Suppressor analysis yielded two intragenic suppressors and seven independent isolates of an allele-specific extragenic suppressor we named tos1; tos1 is not allelic to any genes predicted to encode type I topoisomerase-related proteins. The two intragenic suppressors were tested for allele-specificity; the results revealed a complex pattern of suppression between heat-sensitive and cold-sensitive top2 alleles. These top2 mutations may have compensatory effects on the general stability of the protein.

Expression of biologically active hormone-sensitive lipase in mammalian (COS) cells

cDNAs encoding rat adipose tissue hormone-sensitive lipase were expressed in COS cells, under the control of the SV40 promoter to half the level in rat adipocytes, the richest native source of the enzyme. A cDNA lacking most of the long 5'-untranslated region of the full-length rat hormone-sensitive lipase cDNA was, with regard to the lipase activity, on the average 70% more efficiently expressed that the full-length cDNA. The recombinant protein was almost identical to hormone-sensitive lipase of rat adipose tissue with respect to specific activity, susceptibility to inhibitors, molecular size, phosphorylation and activation by cyclic AMP-dependent protein kinase. The described eukaryotic expression system will allow analysis of effects of amino acid substitutions introduced into the lipase molecule by site-directed mutagenesis.

The metabolism of ethyl esters of fatty acids in adipose tissue of rats chronically exposed to ethanol

The concentration of ethyl esters of fatty acids as well as the activity of the enzyme synthesizing these esters (fatty acid ethyl ester synthase) were determined in adipose tissue of rats ingesting ethanol (9-16 g/kg body weight/day) for different periods of time. After 10 and 17 weeks of ethanol exposure about 300 nmol of ethyl esters of oleic, palmitic, stearic, and linoleic acids were found per gram adipose tissue. The ethyl esters disappeared after 1 week of abstinence. Closer analyses, using radioactive ethanol, revealed a half-life of the esters of less than 24 hr. The bulk of the esters was found in a membrane preparation of isolated adipocytes. Hormone-sensitive lipase hydrolyzed emulsified ethyl oleate as efficiently as that of trioleoylglycerol, but in mixed ethyl oleate/trioleoyl glycerol particles the hydrolysis of ethyl oleate was slower, suggesting a decreased accessibility. Synthase activity was found in adipose tissue from rats not exposed to ethanol. It doubled after 10 and 17 weeks of ethanol and decreased with a half-life of at least a week after abstinence. It was concluded that ethyl esters of fatty acids are formed in rat adipose tissue as previously shown in other tissues. They seem to be stored mainly in membranous parts of the adipocytes. Synthase activity is induced by ethanol. The elevated activity has a longer half-life, and may be useful as an indicator of alcohol abuse.

Sequelae of lateral ovarian transposition in unirradiated cervical cancer patients

The sequelae of lateral ovarian transposition (LOT) in cervical cancer patients has been examined only in the light of the effect of pelvic radiation therapy on ovarian preservation. Preservation of ovarian function has not been examined in the absence of radiation therapy, and symptomatic ovarian cyst formation in transposed ovaries with the need for subsequent surgery has not been addressed in either radiated or unirradiated cervical cancer patients. We studied 84 premenopausal FIGO stage IA or IB cervical cancer patients treated by primary radical hysterectomy between the years 1978 and 1988. None of these patients received adjuvant radiation therapy. Fifty-nine of eight-four patients had radical hysterectomy (RH) without LOT. These patients were compared to 25 of 84 patients who had LOT in addition to RH. The incidence of symptomatic ovarian cysts, the majority requiring operative intervention, was 24% in the ovarian transposition patients as compared to 7.4% in those who had RH alone. This threefold increase in symptomatic benign ovarian cyst formation in the translocated ovary was significant (P = .048). On the other hand, LOT in these RH patients does not appear to increase the incidence of early menopause (P greater than 0.05). On follow-up of those patients who did not incur additional surgery or radiation, 4.3% became menopausal, as compared to 4.1% of those patients undergoing RH alone, with the mean ages of the two groups being comparable.

Cloning by function: an alternative approach for identifying yeast homologs of genes from other organisms

Studies of cell physiology and structure have identified many intriguing proteins that could be analyzed for function by using the power of yeast genetics. Unfortunately, identifying the homologous yeast gene with the two most commonly used approaches--DNA hybridization and antibody cross-reaction--is often difficult. We describe a strategy to identify yeast homologs based on protein function itself. This cloning-by-function strategy involves first identifying a yeast mutant that depends on a plasmid expressing a cloned foreign gene. The corresponding yeast gene is then cloned by complementation of the mutant defect. To detect plasmid dependence, the colony color assay of Koshland et al. [Koshland, D., Kent, J. C. & Hartwell, L. H. (1985) Cell 40, 393-403] is used. In this paper, we test the feasibility of this approach using the well-characterized system of DNA topoisomerase II in yeast. We show that (i) plasmid dependence is easily recognized; (ii) the screen efficiently isolates mutations in the desired gene; and (iii) the wild-type yeast homolog of the gene can be cloned by screening for reversal of the plasmid-dependent phenotype. We conclude that cloning by function can be used to isolate the yeast homologs of essential genes identified in other organisms.

Incorporation of hormone-sensitive lipase into phosphatidylcholine vesicles

Enzymatically active, detergent-solubilized purified hormone-sensitive lipase (HSL) was incorporated into phosphatidylcholine (PC) vesicles, using a detergent-dialysis procedure with small PC vesicles, obtained by sonication, as phospholipid source and CHAPS, a zwitterionic bile-salt derivative, as detergent. Association of enzyme protein with the PC vesicles was verified by floatation in a discontinuous dextran gradient and by gel chromatography. An average of 35% of added HSL was incorporated into the vesicles. The vesicles were shown, by quasi-elastic light scattering and electron microscopy, to have a diameter of approximately 160 nm. The vesicle-associated HSL could be phosphorylated by cyclic AMP-dependent protein kinase. The vesicles were stable, both with regard to enzyme activity and size, for at least 4 days when stored at 4 degrees C. The preparation of detergent-free, vesicle-associated and stable HSL provides new possibilities to study some of its properties, and supports and extends the previous report (Holm, C., Fredrikson, G., and Belfrage, P., J. Biol. Chem. 261, 15659-15661, 1986) which demonstrated the amphiphilic character of HSL.

Segregation of recombined chromosomes in meiosis I requires DNA topoisomerase II

To understand better the similarities and differences between meiosis and mitosis, we examined the meiotic role of DNA topoisomerase II, an enzyme that is required mitotically to disentangle sister chromatids at the time of chromosome segregation. In meiosis, we found that topoisomerase II is required only at the time of nuclear division. When cold-sensitive top2 mutants are induced to sporulate at the restrictive temperature, they undergo premeiotic DNA synthesis and commitment to meiotic levels of recombination but fail to complete the first meiotic nuclear division. The introduction of a mutation blocking recombination relieves the requirement for topoisomerase II in meiosis I. These results suggest that topoisomerase II is required at the time of chromosome segregation in meiosis I for the resolution of recombined chromosomes.

Assignment of seven genes to distinct intervals on the midportion of human chromosome 19q surrounding the myotonic dystrophy gene region

Hybridization studies using a panel of somatic cell hybrids with subchromosomal segments of 19q have localized the genes encoding hormone-sensitive lipase (LIPE), carcinoembryonic antigen (CEA), and small nuclear ribonucleoprotein polypeptide A (SNRPA) to various regions of 19q13.1; the cellular receptor for poliovirus sensitivity (PVS) to 19q13.2; and the genes coding for prostate-specific antigen (APS), human pancreatic kallikrein (KLK1), and small nuclear ribonucleoprotein 70-kD polypeptide (SNRP70) to 19q13.3----qter. Our results exclude several of these genes from being seriously considered as a candidate for the myotonic dystrophy gene on 19q.

Human adipose tissue hormone-sensitive lipase: identification and comparison with other species

The mRNA for human hormone-sensitive lipase (HSL) was identified using Northern blot analysis and a cDNA-probe for rat HSL. As in the rat, human adipose tissue expresses a single mRNA species of 3.3 kb. Using Western blotting with a polyclonal rabbit antibody towards rat adipose tissue HSL, the corresponding enzyme in human adipose tissue was identified with an apparent 88 kDa polypeptide, thus slightly larger than the rat and bovine 84 kDa, and the mouse and guinea-pig 82 kDa species. Additional evidence for the identification was provided by the inhibition of HSL diacylglycerol lipase activity by the anti-rat HSL antibody, and by NaF, DFP and Hg2+, known inhibitors of HSL. The concentration of the enzyme, as reflected by its activity per g tissue and the specific activity was about two thirds of that in the rat adipose tissue (200 g rats). The identification of the human enzyme protein made it possible to directly demonstrate its phosphorylation by cAMP-dependent protein kinase, thus extending the previous report regarding activation of the lipase with this kinase and ATP-Mg2+ in human adipose tissue extracts (Khoo, J.C., Aquino, A.A. and Steinberg, D. (1974) J. Clin. Invest. 53, 1124-1131).

Differential requirement of DNA replication for the cytotoxicity of DNA topoisomerase I and II inhibitors in Chinese hamster DC3F cells

The cytotoxicity of topoisomerase inhibitors is thought to result from the induction of enzyme-mediated DNA breaks. The fact that these breaks reverse rapidly in cells programmed to die, led us to investigate further the cytotoxic mechanisms of topoisomerase I (camptothecin) and topoisomerase II inhibitors (VP-16 and amsacrine) in Chinese Hamster lung fibroblasts (DC3F). Exposures (30 min) to camptothecin produced limited cell killing with approximately 20% of the cells naturally resistant. This resistance was overcome by increasing the drug exposure time. Inhibition of DNA synthesis by 5-min pretreatments with aphidicolin or hydroxyurea abolished the cytotoxicity of camptothecin without changing the level of camptothecin-induced DNA breaks. A good correlation was found between the degree of DNA synthesis inhibition by aphidicolin and the reduction of camptothecin cytotoxicity. In similar experiments performed with topoisomerase II inhibitors, aphidicolin prevented only partially against VP-16- and amsacrine-induced cytotoxicities, yet had no effect upon drug-induced DNA breaks. These results indicate that the production of topoisomerase-mediated DNA breaks by antitumor drugs is not sufficient for cell killing. Instead, an interference of moving DNA replication forks with drug-stabilized topoisomerase-DNA complexes is critical for cell death. The cytotoxicity of camptothecin seemed to be completely related to this process, while that of topoisomerase II inhibitors seemed to involve additional mechanisms in DC3F cells.

Rapid purification of detergent-solubilized bovine hormone-sensitive lipase by high performance hydrophobic interaction chromatography

Hormone-sensitive lipase (HSL), the enzyme controlling the rate of adipose tissue lipolysis and also possibly involved in the regulation of steroidogenesis, has been purified from bovine omental adipose tissue. Partially detergent-solubilized, delipidated and purified HSL was obtained through step-elution at conventional DEAE ion-exchange chromatography, followed by concentration on hydroxylapatite. High performance hydrophobic interaction chromatography (HPHIC) on phenylsilica then resulted in an increase of HSL protein purity from 2% to more than 70%. Final purification of the enzyme to apparent homogeneity (greater than 95% protein purity), concentration and removal of most of the detergent was obtained by high performance cation exchange chromatography on Mono S. At least 0.5 mg of highly stable HSL was obtained from 5 kg of bovine omental fat within four working days. The purified lipase had a lower specific activity than previously reported for the corresponding rat enzyme but the preparations have proved very useful for enzyme structure studies and as an antigen.

DNA topoisomerase II must act at mitosis to prevent nondisjunction and chromosome breakage

The hypothesis that DNA topoisomerase II facilitates the separation of replicated sister chromatids was tested by examining the consequences of chromosome segregation in the absence of topoisomerase II activity. We observed a substantial elevation in the rate of nondisjunction in top2/top2 cells incubated at the restrictive temperature for one generation time. In contrast, only a minor increase in the amount of chromosome breakage was observed by either physical or genetic assays. These results suggest that aneuploidy is a major cause of the nonviability observed when top2 cells undergo mitosis at the restrictive temperature. In related experiments, we determined that topoisomerase II must act specifically during mitosis. This latter observation is consistent with the hypothesis that the mitotic spindle is necessary to allow topoisomerase II to complete the untangling of sister chromatids.

Hydroxyurea potentiation of the antineoplastic activity of cyclophosphamide and 4'-(9-acridinylamino)methanesulfon-M-anisidide (AMSA) in the brown Norway rat myelocytic leukemia model

The activities of hydroxyurea (HU), 4'-(9-acridinylamino)methanesulfon-M-anisidide (AMSA) and cyclophosphamide (CY) were examined in the brown Norway rat myelocytic leukemia model in experiments designed to determine the synergy, optimal drug sequencing, and therapeutic index of combinations of these agents. A single dose of CY or four consecutive daily doses of AMSA produced increased survival in leukemic rats, with a positive-slope dose-response curve up to the maximum tolerated dose (MTD). HU at 1/2 MTD produced a minimal antileukemic effect but significantly potentiated the antineoplastic activity of 1/2 MTD of CY or AMSA with no significant toxic death rate. Drug-sequence experiments demonstrated that maximal synergy was achieved when HU was given immediately after CY but immediately before or during AMSA administration. No significant cure rate was seen with any CY/HU or HU/AMSA sequence. The three drugs given in the sequence of CY followed 3 days later by HU and AMSA simultaneously, however, was curative in the majority of rats with advanced leukemia, whereas other sequences were more toxic or less effective. Each of the drugs in these experiments was given at 1/2 of its single-agent MTD. HU significantly potentiates the antineoplastic effect of CY and AMSA in a drug-sequence-dependent manner in this model, apparently with an improved therapeutic index.

Portal venous blood flow during and after cholecystectomy

Eight patients scheduled for cholecystectomy were studied with the aim of defining the pattern of portal venous blood flow in the recovery phase after anaesthesia and abdominal surgery. The continuous thermodilution technique was used for measuring portal flow, via a thermodilution catheter placed in the portal vein after intraoperative umbilico-portal cannulation. Measurement of portal blood flow was begun during surgery and was repeated 2, 4, 6, 8, 12, 24 and 48 hours postoperatively. The flow rate 48 hours after surgery was 977 +/- 182 ml.min-1 (mean +/- SEM), compared with 605 +/- 89 ml.min-1 (p less than 0.05) during cholecystectomy. No significant deviation from the mean intraoperative portal blood flow was found at any of the post-operative measuring points prior to 48 hours. The study's results confirmed the applicability of the thermodilution technique for measuring portal blood flow in awake patients after surgery.

Hormone-sensitive lipase: sequence, expression, and chromosomal localization to 19 cent-q13.3

Hormone-sensitive lipase, a key enzyme in fatty acid mobilization, overall energy homeostasis, and possibly steroidogenesis, is acutely controlled through reversible phosphorylation by catecholamines and insulin. The 757-amino acid sequence predicted from a cloned rat adipocyte complementary DNA showed no homology with any other known lipase or protein. The activity-controlling phosphorylation site was localized to Ser563 in a markedly hydrophilic domain, and a lipid-binding consensus site was tentatively identified. One or several messenger RNA species (3.3, 3.5, or 3.9 kilobases) were expressed in adipose and steroidogenic tissues and heart and skeletal muscle. The human hormone-sensitive lipase gene mapped to chromosome 19 cent-q13.3.

Effects of dopamine on the portal circulation after therapeutic hepatic artery ligation

The effects of exogenous dopamine (2, 4 and 6 micrograms.kg-1.min-1 i.v.) on the portal circulation were studied in six patients following therapeutic hepatic artery ligation. Portal blood flow (PBF) was measured by the continuous thermodilution technique. Portal venous pressure (PVP, n = 3) was monitored through the thermodilution catheter to allow derivation of preportal vascular resistance (PVR). Blood samples were taken through the portal venous catheter for measurement of dopamine. A significant increase in PBF and a decrease in PVR were observed during graded i.v. dopamine infusion. Thus, PBF was 961 +/- 119 ml.min-1 during control conditions and increased to 1446 +/- 221 ml.min-1 during the dopamine infusion at 6 micrograms.kg-1.min-1. No significant changes in mean arterial pressure or PVP were observed during dopamine administration. The pharmacokinetics of dopamine did not differ from that previously reported in patients with an intact arterial supply. In conclusion, our data indicate that exogenous dopamine consistently increases PBF by preportal vasodilation, also in patients with a surgically restricted hepatic arterial blood supply.

Bone scintigraphy in post-traumatic reflex dystrophy

Twenty-five patients presenting consecutively with persistent pain and tenderness, edema, and vasomotor instability in an extremity following trauma to the same extremity were clinically diagnosed as having early post-traumatic reflex dystrophy (PRD). All underwent scintigraphy with 99mTechnetium methylene diphosphonate before institution of prednisolone treatment. The time lag between the occurrence of the initial trauma and scintigraphic imaging averaged 11.5 weeks. Of 25 scintigrams, 24 showed multiple periarticular accentuation in the affected extremity. Scintigraphy is a useful clinical aid to establish the diagnosis of early PRD.

Hormone-sensitive lipase in brown adipose tissue: identification and effect of cold exposure

Hormone-sensitive lipase (HSL) in brown adipose tissue from mice was identified through immunoprecipitation with a polyclonal antibody (anti-HSL) towards rat white fat HSL and Western blotting. An 82 kDa polypeptide, slightly smaller than the rat white fat HSL 84 kDa subunit, was detected and its identity as HSL verified by inhibition properties. The HSL concentration per g tissue was several-fold higher in the mouse brown adipose tissue than in the rat white adipose tissue, but the specific activities per mg protein were similar. Cold-exposure (4 degrees C) of the mice for 24 h approximately doubled the HSL concentration but this increase parallelled the overall protein increase and did not reflect a specific effect on the HSL.

Immunological evidence for the presence of hormone-sensitive lipase in rat tissues other than adipose tissue

A polyclonal rabbit antibody was used to detect hormone-sensitive lipase in rat organs other than white adipose tissue. Inhibition of tissue diacylglycerol lipase activity by the anti-hormone-sensitive lipase, and by NaF, Hg2+ and diisopropyl fluorophosphate, known inhibitors of the hormone-sensitive lipase, demonstrated its presence in the adrenals, ovaries, testes, heart and skeletal muscle, but not in the liver and kidneys. After enrichment by immunoprecipitation an immunoreactive protein, corresponding to the adipose tissue hormone-sensitive lipase 84 kDa subunit, and some additional, higher Mrapp proteins, were detected by Western blotting in the same tissues. The adipose tissue contained greater than 80% of the total hormone-sensitive lipase, with 5-10- and 50-100-fold lower specific activity in the steroid-producing and the muscle tissues, respectively.

Demonstration of the amphiphilic character of hormone-sensitive lipase by temperature-induced phase separation in Triton X-114 and charge-shift electrophoresis

Temperature-induced phase separation in Triton X-114 (Bordier, C. (1981) J. Biol. Chem. 256, 1604-1607) and charge-shift electrophoresis (Helenius, A., and Simons, K. (1977) Proc. Natl. Acad. Sci. U. S. A. 74, 529-532) were used to examine the amphiphilic character of hormone-sensitive lipase, purified from rat adipose tissue. In contrast to ATP-citrate lyase, a reference hydrophilic protein, the lipase was shown to partition predominantly (approximately 80%) into the detergent-rich phase upon phase separation in Triton X-114. Furthermore, its electrophoretic mobility was markedly shifted anodally and cathodally upon charge-shift electrophoresis in the presence of sodium taurodeoxycholate and cetyltrimethylammonium bromide, respectively. The results demonstrate that hormone-sensitive lipase possesses detergent-binding hydrophobic domain(s) and exhibits the same amphiphilicity as typical intrinsic membrane proteins.

Portal blood flow in man during graded positive end-expiratory pressure ventilation

The cardiovascular response to graded PEEP ventilation (5-10 cm H20) was studied peroperatively in patients undergoing cholecystectomy (n = 8) or hepatic tumour surgery (n = 3). Portal blood flow was measured by the continuous thermodilution technique and cardiac output, in a sub-group of the patients, by impedance cardiography. A parallel reduction in cardiac output and portal blood flow was demonstrated in patients undergoing cholecystectomy as the result of the application of PEEP. Thus, ventilation with 5 cm H2O of PEEP elicited a 17% decrease in cardiac output and a 26% decrease in portal blood flow. During 10 cm H2O of PEEP cardiac output decreased by 22% and portal blood flow by 32%. However, there were no significant changes in preportal tissue perfusion pressure by the application of PEEP and preportal vascular resistance increased by 22% and 30%, respectively. This indicates that a vasoconstrictor response, elicited by PEEP, in the preportal tissue is the predominating mechanism for the observed decrease in portal blood flow. Systemic oxygen transport decreased by 214 ml/min during PEEP ventilation, but preportal tissue oxygen utilization was not significantly changed due to a concurrent increase (2.9%; p less than 0.05) in oxygen extraction.

A rapid, efficient method for isolating DNA from yeast

A method is described for the purification of chromosomal and plasmid DNA from the yeast Saccharomyces cerevisiae. This method is rapid, gives 75% of theoretical yield, and produces DNA that can be cut with restriction endonucleases. Yeast cells are treated with zymolyase, and the resulting spheroplasts are lysed in the presence of the chaotropic agent guanidine hydrochloride. After a brief ethanol precipitation, protein is removed by treatment with proteinase K followed by phenol-chloroform extraction. After ethanol precipitation, the DNA is sufficiently pure for restriction analysis or for the transformation of Escherichia coli.

DNA topoisomerase II is required at the time of mitosis in yeast

We have constructed five new temperature-sensitive DNA topoisomerase II mutations and have analyzed their physiological consequences in yeast. Several lines of evidence suggest that the activity of topoisomerase II is required specifically at the time of miosis. First, top2 mutations cause dramatic lethality at the restrictive temperature, but only if the mutant cells are actively traversing the cell cycle. Second, temperature-shift experiments with synchronized cultures show that the onset of inviability coincides with the time of mitosis. Third, fluorescence microscopy reveals that the normal progression of mitosis is disturbed in mutant cells at the restrictive temperature. Finally, inviability at the restrictive temperature is prevented by nocodazole, an inhibitor of tubulin polymerization that prevents formation of the mitotic spindle. These results are consistent with the hypothesis that the essential function of topoisomerase II is to allow the separation of intertwined chromosomal DNA molecules during mitosis.

Purification of mouse brain (Na+ + K+)-ATPase catalytic unit, characterization of antiserum, and immunocytochemical localization in cerebellum, choroid plexus, and kidney

The denatured catalytic polypeptide of mouse brain (Na+ + K+)-adenosine triphosphatase(ATPase) was separated from microsomal membranes on polyacrylamide gels and used as an immunogen. The antiserum, characterized by immunoblots, recognizes the polypeptide corresponding to the catalytic unit in various fractions of mouse brain and cross-reacts with the catalytic unit from lamb kidney, duck salt gland, and electroplax. The same polypeptide in brain and salt gland is recognized by antiserum raised against purified lamb kidney enzyme. Light microscopy was performed with the peroxidase-conjugated second antibody method. In mouse cerebellum, immunochemical staining outlines Purkinje cell and granule cell perikarya. Intense activity is associated with regions of high synaptic content including the pericellular basket meshes and preaxonal regions of Purkinje cells and the glomeruli in the granular layer. In the molecular layer, the neuropil is diffusely reactive with distinct vertically oriented processes evident. White matter exhibits light stain deposition. Choroid plexus presents abundant reaction product only at ependymal apical surfaces, while the ependymal lining of the fourth ventricle displays little or no immunoreactivity. Specificity of the antiserum was demonstrated further in mouse kidney where staining conforms to the well-characterized localization of the enzyme along basolateral surfaces of cortical and medullary tubules. The biochemical and immunocytochemical data show the efficacy of generating antisera to brain (Na+ + K+)-ATPase using catalytic polypeptide as an immunogen.

Influence of dixyrazine on intestinal and renal vasoconstrictor responses during fentanyl-nitrous oxide anaesthesia

In cats (n = 24) anaesthetized with fentanyl-nitrous oxide and diazepam, stimulation of the hypothalamic defence-alarm area (DA) or afferent activation of somatic pain fibres (SA), elicited a pronounced increase in intestinal (DA 297%, SA 107%) and renal (DA 214%, SA 90%) vascular resistance as well as a decrease in diuresis. These stress-related responses were markedly counteracted by dixyrazine (0.15-0.5 mg X kg-1 b.w.i.v.), especially in the kidney where the subsequent increase in vascular resistance to DA and SA stimulations amounted to only 25% and 13%, respectively, while diuresis increased. Corresponding data for stimulation-induced increases in intestinal vascular resistance after dixyrazine were DA 156% and SA 28%. Dixyrazine is suggested to act both through interaction with peripheral alpha-adrenergic mechanisms in control of vascular tone and through central nervous cardiovascular reflex depression. In man (n = 7), during a similar form of anaesthesia, portal vein blood flow (1137 +/- 177 ml) was measured by the continuous thermodilution method. Preportal tissue vascular resistance during surgery decreased significantly (11.3 vs 8.7 kPa X min X ml-1 X 10(-3] after i.v. dixyrazine (0.15 mg X kg-1 b.w.). A concomitant increase in oxygen uptake in preportal tissues occurred (19.9 ml min-1 vs 24.5 ml X min-1).

Portal blood flow in man during surgery, measured by a modification of the continuous thermodilution method

The continuous thermodilution method was applied to measurement of peroperative portal venous blood flow in man in relation to hepatic surgery during steady-state enflurane nitrous oxide anaesthesia. Portal-vein catheterization through the umbilical vein for cytostatic administration and blood flow measurements was successful in 14 out of 17 patients with primary or secondary liver tumours. Mean portal blood flow was 1195 +/- 179 ml X min-1 (mean +/- SEM), corresponding to 17.6 +/- 2.9 ml X min-1 X kg-1 body weight. Mean oxygen consumption in the prehepatic splanchnic area was 0.27 +/- 0.04 ml X min-1 X kg-1. No significant complications were associated with the catheterization or flow recording procedures. The described method offers possibilities for haemodynamic and pharmacokinetic investigations in man.

Sensitivity to the Yeast Plasmid 2mu DNA is conferred by the nuclear allele nibl

Two strains of Saccharomyces carlsbergensis that lacked the plasmid 2mu DNA responded differently when the plasmid was introduced into them. In one strain, cells lacking 2mu DNA ("cir0") produced the normal "smooth" colony morphology, but cells bearing 2mu DNA ("cir+") produced heterogeneous "nibbled" colonies. In the second strain, both cir+ and cir0 strains exhibited a smooth colony morphology. Crosses between these strains revealed that a single recessive nuclear gene, called nibl, conferred the nibbled colony morphology in the presence of 2mu DNA. By a series of backcrosses, nibl was introduced into a Saccharomyces cerevisiae background. nibl caused a nibbled colony morphology in this background just as it did in S. carlsbergensis. nibl was mapped to the left arm of chromosome XVI. Twelve independent smooth revertants were isolated from two nibl [cir+] strains. Seven were analyzed, and all were found to be chromosome VII disomes. Chromosome VII disomy and suppression of the nibbled phenotype cosegregated in crosses. Thus, chromosome VII disomy can suppress the nibbled phenotype. The results of other experiments (C. Holm, Cell 29:585-594, 1982) indicate that the nibbled colony morphology is the result of lethal sectoring and that the lethality is caused by a high copy number of 2mu DNA. I suggest, therefore, that the product of the nibl gene may play a role in controlling the copy number of 2mu DNA. Possible models for the suppression of the nibbled phenotype by chromosome VII disomy are discussed.

Clonal lethality caused by the yeast plasmid 2 mu DNA

Strains of Saccharomyces that carry the nib allele of a nuclear gene exhibit a "nibbled" colony morphology if they also harbor the plasmid 2 mu DNA. I have found that the expression of the nibbled phenotype is correlated with the presence of a subpopulation of abnormally large cells that give rise to mortal clones. Large cells apparently become large as a consequence of a defect in DNA replication or nuclear division. Large nib cells contain twice as much 2 mu DNA per microgram of total DNA as small nib cells do, and elevated 2 mu DNA copy number is the cause, not the effect, of increased cell size. It appears that the NIB allele can prevent an increase in 2 mu DNA copy number, but cannot produce a decrease once the copy number has exceeded the normal level. I propose, therefore, that the NIB gene product normally represses the amplification of 2 mu DNA copy number, and that the nib allele is partially defective in this function.

Morphological and electrophysiological mapping of giant neurons in the suboesophageal ganglia of Helix pomatia

1. To reveal the morphology of the suboesophageal ganglia of Helix pomatia, the connective tissue was completely removed and the preparations stained whole-mount with methyl green-pyronin G to display the relative locations of the neurons. 2. Fifteen large cells which could be recognized as individuals in at least 75% of the preparations investigated, were morphologically identified by size, position and color. 3. The cells were electrophysiologically characterized with respect to spontaneous activity, synaptic input from peripheral nerves, and response to application of drugs (e.g. ACh, DA and 5-HT). 4. The peripheral axonal projections of eight of the major identified cells were investigated by intracellular CoCl2 injection and by cobalt backfilling of the peripheral nerves.

Optical thin film production with continuous reoptimization of layer thicknesses

For various reasons when optical multilayer systems are constructed the thicknesses of individual layers depart from the desired values. This often results in an unacceptable performance of the filter. In this paper a production method for nonabsorbing multilayer coatings is described, which is based on monochromatic transmittance monitoring and which, to a certain degree, compensates for these errors. After the deposition of each layer a computer program is provided with the actual monitoring data from which the layer thickness is deduced. The program then reoptimizes the performance of the system by changing the thicknesses of the remaining layers. A numerical and experimental study has been made of the production of a seven-layer neutral beam splitter on glass. Theoretical data are also given for an AR coating on glass.

[Emancipatory rehabilitation in logopedics -- comments from the medico-rehabilitative viewpoint (author's transl)]

In the Federal Republic of Germany speech disturbances, as sub-group of communication disorders, are treated by two professional groups: a) free practising logopedists who chose their team themselves as well as logopedists who are working in a clinic team and b) "Sprachheilpädagogen" (speech therapists) working at special education facilities. Irrespective of the age of the patient, treatment by logopedists is paid by the health insurance funds; special education therapy is paid by the financially responsible school agencies. The basis of the disease is not a deviation but a disturbance of the central nervous system which can be determined by medical, phoniatric-neurological diagnostic means.

[EEG-results in early-treated children with phenylketonuria 4 through 10 years under treatment (author's transl)]

EEG-results in 21 children with Phenylketonuria (PKU), put on a diet at least since their 3rd month of life, now aged 4 through 10 years, with normal psychomotor development, lacking abnormal neurological signs, are compared with the results in 796 healthy children of the same age. Visual evaluation and frequency analysis of the background activity of the EEGs reveal no differences between children with PKU and controls. Generally, there is no close correlation between mean plasma levels of phenylalanine (phe-means) during treatment, and the composition of the EEG when combined age groups are compared. But a trend can be demonstrated: In the small group of 8 years old children phe-means up to 6 mg-% can be associated with a faster (alpha), and phe-means above 6 mg-% with a slower (theta) background activity. The frequency of metabolic derailment (single phe-values above 10 mg-%) does not correlate with the EEG. Focal and generalized hypersynchronous activity (HSA) is observed significantly more often even in early treated, normally developing children with PKU. In children aged 4--8 years, HSA is associated with a high proportion of slow waves compared with those who do not display HSA. In children 9 and 10 years old, however, no such differences can be seen. It is hypothesised that even early treated children with PKU, in their first years show a retardation in the development of their background activity but catch up by 9--10 years. It still remains uncertain whether further age-appropiate development of the EEG can be observed after liberating or discontinuing the dietary regimen at this age.

Biochemical and physiological studies of the yeast virus-like particle

A study was made of the virus-like particle (VLP) of Saccharomyces cerevisiae S7. This strain contains elevated amounts of P1 double-stranded ribonucleic acid (dsRNA) but no P2 dsRNA. The amount of dsRNA contained in cells grown on a fermentable carbon source (glucose) was compared with that in cells grown on a nonfermentable carbon source (ethanol). It was found that ethanol-grown cells contain higher levels of dsRNA than glucose-grown cells. In the former, the amount of dsRNA increased during the logarithmic phase of growth, whereas in the latter it increased during the transition from the logarithmic to the stationary phase. A method was devised to isolate VLPs from these cells by using CsCl gradients, and the yield was assessed by monitoring the recovery of dsRNA. Three proteins were found to be tightly associated with these particles. They have molecular weights of 75,000, 53,000, and 37,000. Together they account for almost all of the coding capacity of the P1 dsRNA that the VLP contains.

The economy of the EMI-scanner

It is shown-taking in consideration the local circumstances-that the EMI scanning of the brain is less expensive than pneumoencephalography percutaneus carotid angiography or cerebral four vessel angiography.

[Age-dependent electric response audiometry (ERA)-findings in correlation with speech development (author's transl)]

The occurrence of periods of speech-certainty and speech-uncertainty can be observed in normal as well as in children impaired with hearing, voice and speech defects. This behaviour of voice and speech development has not yet been explained by subjective pure-tone or speech audiometry. 19 normal children were grouped into four age populations according to electroglotto- and phonographic analysis. This collective was then examined by Electric Response Audiometry (ERA) at the frequencies of 0.5 kHz, 1.0 kHz, 2.0 kHz, and 4.0 kHz. Speech-certainty was observed at a mean age of 4.5 years (Group II) and 6.5 years (Group IV), whereas speech-uncertainty was found at a mean age of 2.5 years (Group I) and 5.5 years (Group III). The supraliminal ERA results of contralteral pickup were evaluated in amplitude and in behaviour of latency. Because of the variety of ERA-characteristics, the age-dependent and frequency-specific development of the acoustic system is figured by integration below the characteristics in the supraliminal range. The mathematical result shows two opposite regions as well as the "hearing dynamic" as at the "dynamic of the behaviour of latency": a low-frequency region of 0.5 and 1.0 kHz and a high-frequency region of 2.0 and 4.0 kHz. Evaluation of the electroglottograms following Fourier's analysis shows a typical amplitude spectrum at speech-certainty and at speech-uncertainty.