CYP-2E1 inhibitors partially ameliorate the changes in hepatic fatty acid composition induced in rats by chronic administration of ethanol and a high fat diet

The objective of this study was to determine if ethanol-induced cytochrome P450 2E1 (CYP2E1) was responsible for the changes in hepatic fatty acids observed in rats fed ethanol intragastrically. We hypothesized that if CYP2E1 was responsible for these changes then CYP2E1 inhibitors fed with ethanol should prevent the ethanol-induced changes in fatty acids. We compared the fatty acid composition of the liver in rats fed ethanol alone with that in rats fed ethanol with the CYP2E1 inhibitors, diallyl sulfide and phenethyl isothiocyanate. In each experiment, rats pair-fed isocaloric glucose were included to determine the effect of the inhibitors alone on the hepatic fatty acid composition. The lobular distribution of succinic dehydrogenase was determined histochemically because the lobular distribution of CYP2E1 shifts to the periportal area in livers of rats fed CYP2E1 inhibitors. The CYP2E1 inhibitors ameliorated both the ethanol-induced changes in fatty acids and the shift in succinic dehydrogenase. Rats fed ethanol but no inhibitors had significantly greater hepatic total fatty acids and triglyceride fractions than when inhibitors were fed ethanol. Ethanol altered the fatty acid composition compared with rats fed ethanol with CYP2E1 inhibitors. The ratio of 20:4/18:2 was significantly lower and that of 18:1/18:0 was greater in alcohol-fed rats compared with their pair-fed controls. The CYP2E1 inhibitors inhibited many of the above effects of alcohol. The data suggest that the changes in the fatty acid composition due to ethanol ingestion are the result of CYP2E1-dependent lipid peroxidation and fatty acid metabolism.

Regional and segmental localization of AE2 anion exchanger mRNA and protein in rat kidney

Chloride/base exchange activity has been detected in every mammalian nephron segment in which it has been sought. However, in contrast to the Cl-/HCO3- exchanger AE1 in type A intercalated cells, localization of AE2 within the kidney has not been reported. We therefore studied AE2 expression in rat kidney. AE2 mRNA was present in cortex, outer medulla, and inner medulla. Semiquantitative polymerase chain reaction of cDNA from microdissected tubules revealed AE2 cDNA levels as follows [copies of cDNA derived per mm tubule (+/- SE)]: proximal convoluted tubule, 688 +/- 161; proximal straight tubule, 652 +/- 189; medullary thick ascending limb, 1,378 +/- 226; cortical thick ascending limb, 741 +/- 24; cortical collecting duct, 909 +/- 71; and outer medullary collecting duct, 579 +/- 132. AE2 cDNA was also amplified in thin limbs and in inner medullary collecting duct. AE2 polypeptide was detected in all kidney regions. AE2 mRNA and protein were also detected in several renal cell lines. The data are compatible with the postulated roles of AE2 in maintenance of intracellular pH and chloride concentration and with its possible participation in transepithelial transport.

Hypoxemia up-regulates interleukin-8 stimulated phagocytosis of polymorphonuclear leukocytes by differential regulation of CD32w and CD35 messenger RNA expression

BACKGROUND

The purpose of these studies was to investigate the effect of hypoxemia on interleukin-8 (IL-8) regulation of phagocytosis and surface opsonic receptor expression of whole blood polymorphonuclear leukocytes (PMNs).

METHODS

Whole blood PMNs were rendered hypoxemic (PvO2 less than 15 mm Hg) or normoxic (PvO2 equals 60 to 80 mm Hg) and incubated with IL-8 (50 ng/ml) before the sequential addition of serum-opsonized fluorescent microspheres (emission wavelength, 560 nm) and fluorescein isothiocyanate-conjugated mouse anti-human CD32w or CD35 antibodies (emission wavelength, 513 nm). Concomitant two color flow cytometric analysis was then performed to measure the mean channel fluorescence (MCF) and the percentage of positive PMNs. Steady-state messenger RNA levels for CD32w and CD35 were quantitated by means of Northern blot analysis by using total RNA extracted from purified PMNs from each study group.

RESULTS

Hypoxemia increased IL-8 stimulated PMN phagocytosis (percentage of positive PMNs, 38 +/- 1.5 versus 27 +/- 2.0, MCF, 5491 +/- 182 versus 4060 +/- 121 for hypoxemia plus IL-8 versus normoxia plus IL-8, respectively; p < 0.05). Hypoxemia increased IL-8 stimulated PMN expression of CD32w and CD35 (MCF CD32w, 791 +/- 105 versus 336 +/- 81; MCF CD35, 542 +/- 87 versus 254 +/- 41; p < 0.05). Under normoxic conditions IL-8 decreased messenger RNA levels for both CD32w and CD35, but under hypoxemic conditions IL-8 increased messenger RNA levels only for CD32w.

CONCLUSIONS

Hypoxemia directly regulates IL-8 control of PMNs by increasing phagocytosis, receptor expression, and messenger RNA for these receptors. Studies investigating cytokine regulation of PMN function need to take into account oxygen tension when establishing the fundamental effects of cytokines on PMN physiology.

A 2D crossover-based map of the human X chromosome as a model for map integration

We have constructed a two-dimensional map of 243 markers on the X chromosome. The average distance between markers ordered by two recombinants is 5.4 centiMorgans (cM), which is reduced to 3.2 cM using a less stringent criterion of one recombinant. Map resolution is enhanced by replacing the usual reference marker format with a 2D format, and the two-recombinant rule is more conservative than the lod 3.0 criterion for order. Taken together, crossover mapping and the 2D format produces maps with greater reliability and higher resolution than maps constructed using currently accepted standards. This first high-density crossover-based map of an entire human chromosome provides a model for integrating physical and genetic maps.

Altered renal expression of the insulin-responsive glucose transporter GLUT4 in experimental diabetes mellitus

Because the insulin-responsive glucose transporter, GLUT4, is expressed in renal vascular and glomerular cells, we determined the effects of experimental diabetes mellitus on GLUT4 expression and glucose uptake by these tissues. Quantitative reverse-transcription polymerase chain reaction studies of microdissected afferent microvessels and renal glomeruli showed that, after 1 wk of diabetes, GLUT4 mRNA was decreased to 26 and 34% of control values, respectively. GLUT4 immunoblots of renal glomerular and microvessel samples showed that GLUT4 polypeptide was decreased to 51% of control values. These results were confirmed by indirect immunofluorescence, which showed decreased GLUT4 expression in glomerular cells and in vascular smooth muscle cells of the afferent microvasculature of diabetic animals. Uptake of the glucose analogue, 2-deoxyglucose, was also depressed in microvessels of diabetic rats to 57% of control values, supporting the conclusion that fewer total glucose transporters were available for glucose uptake into diabetic renal glomerular and microvascular cells. Thus both GLUT4 expression and glucose uptake by glomerular and microvascular cells are decreased in diabetic animals. These results have led us to suggest a mechanism by which decreased renal GLUT4 expression could contribute to glomerular hyperfiltration and hypertension seen in early diabetes.

Localization of a breast cancer susceptibility gene, BRCA2, to chromosome 13q12-13

A small proportion of breast cancer, in particular those cases arising at a young age, is due to the inheritance of dominant susceptibility genes conferring a high risk of the disease. A genomic linkage search was performed with 15 high-risk breast cancer families that were unlinked to the BRCA1 locus on chromosome 17q21. This analysis localized a second breast cancer susceptibility locus, BRCA2, to a 6-centimorgan interval on chromosome 13q12-13. Preliminary evidence suggests that BRCA2 confers a high risk of breast cancer but, unlike BRCA1, does not confer a substantially elevated risk of ovarian cancer.

Comparison of cord blood and peripheral blood mononuclear cells as targets for viral isolation and drug sensitivity studies involving human immunodeficiency virus type 1

We have shown that umbilical cord blood mononuclear cells (CBMC) are at least as sensitive as peripheral blood mononuclear cells (PBMC) for isolation of human immunodeficiency virus type 1 from the PBMC of infected individuals. Viral replication was more efficiently monitored by a p24 antigen capture assay than by a viral reverse transcriptase test, regardless of whether CBMC or PBMC were employed. We also found that CBMC and PBMC yielded similar results with regard to the susceptibility profiles of both wild-type and drug-resistant variants of human immunodeficiency virus type 1 for 3'-azido-3'-deoxythymidine, 2',3'-dideoxycytidine, and the (-) enantiomer of 2',3'-dideoxy-3'-thiacytidine. Finally, viruses isolated on CBMC could be routinely grown on PBMC and vice versa.

Undulator radiation for at-wavelength interferometry of optics for extreme-ultraviolet lithography

Techniques are described for at-wavelength interferometry of multilayer coated optics designed for use in extreme-ultraviolet lithography. Broadly tunable undulator radiation, which covers the spectral region from 45 to 400 A, is described. The coherent power available at these wavelengths is described, and several types of interferometer that might be suitable at these short wavelengths are also described.

Tarnishing of Mo/Si multilayer x-ray mirrors

Multilayer x-ray mirrors of molybdenum and silicon operating at normal incidence at energies just below the Si L(II,III) absorption edges are a key component in the development of soft-x-ray projection lithography. In this application high reflectivity is essential. Aging tests on such reflectors, with Mo as the last layer deposited, show that the structures decline in reflectivity with time when stored in air. Chemical analysis of a well-aged surface by photoelectron spectroscopy techniques reveals that the uppermost Mo layer eventually becomes completely oxidized to MoO(3) and MoO(2) and contaminated with carbonaceous materials. The oxidation can be prevented by storing the mirrors in an oxygen-free atmosphere or by depositing the silicon as the top layer. The reflectivity of tarnished mirrors can be restored by removing the oxides by argon-ion etching or wet chemical methods.

Peripheral nerve regeneration across 14-mm gaps: a comparison of autograft and entubulation repair methods in the rat

A study was conducted to compare the regeneration across 1.4-cm peroneal nerve gaps in rats, repaired with sutured autografts or with artificial nerve grafts. The artificial models were composed of a biodegradable passive conduit made of glycolide trimethylene carbonate, filled with either phosphate-buffered saline or a collagen extracellular matrix. Functional recovery was evaluated by walking track analysis throughout the experiment. After 9 months, the nerves were analyzed by electrophysiology and by qualitative and quantitative histology. Walking track analysis demonstrated the three repair methods to provide statistically equivalent recovery, except at day 195 post-engraftment, when the collagen-filled conduit was superior to the saline-filled conduit. Electrophysiologically, the autograft was superior to the collagen-filled conduit, while the collagen- and saline-filled conduits were equivalent. Quantitative histology demonstrated that normal intact nerve had larger mean myelinated axonal diameters but an equal number of axons to the three repair methods, and that the repair methods were statistically equivalent. While the repair methods had similar histologic and functional outcomes, combined standardized scoring demonstrated that the autograft was superior to the statistically-equivalent entubulation repairs. A collagen gel may serve as an ideal matrix in which to suspend neurotrop(h)ic factors or cells.

Ocular absorption of topically applied FK506 from liposomal and oil formulations in the rabbit eye

PURPOSE

To investigate the use of topically applied FK506, a new immunosuppressive compound, systemic and ocular absorption was determined in serum and various ocular tissues.

METHODS

Two drops of 20 microliters FK506 were applied using oil dissolved (OD-FK506) or liposome-bound (LIP-FK506) drug. FK506 concentrations were measured at intervals of 30, 60, and 120 minutes by immunoassay.

RESULTS

After application of OD-FK506, the highest concentrations of FK506 were found in the cornea and the conjunctiva (200-1200 ng/g) with substantial drug also present in anterior and posterior sclera. Relatively low concentrations were measured in the aqueous and vitreous humors (0.2-1.0 ng/g) of these animals. Using the same treatment regimen, LIP-FK506 was effective in delivering significantly higher drug concentrations (P < 0.05) to all ocular tissues and particularly aqueous humor (5-28 ng/g) and vitreous humor (12-22 ng/g) at all time points. During the observation period drug concentrations produced by LIP-FK506 remained well above the therapeutic range. FK506 levels were not detectable in serum (< 0.2 ng/ml) with either drug formulation.

CONCLUSION

These findings indicate that liposomes may be a promising formulation for topical use of FK506 in ocular immune-mediated diseases.

The effects of photofrin on human Tenon's capsule fibroblasts in vitro

Pharmacological agents that modulate the wound healing process by inhibiting fibroblast proliferation may improve the success of proliferative vitreoretinopathy and glaucoma filtration surgery and may have applications in other surgical fields. It is possible that light-absorbing chemicals can be used to cause photo reactions in proliferating fibroblasts as a means of controlling this wound healing process. We present the effects of photofrin porfimer sodium (serial tenfold dilutions 1000-0.00001 micrograms/ml) on human fibroblasts from Tenon's capsule in vitro, with and without photoactivation with Argon green laser (700 mW for 1 and 5 minutes) and with bright sunlight (for 1 and 5 min). The cell density was measured on day 2 by 3H-thymidine uptake and on day 9 by means of a coulter counter, and optical density was measured in terms of the activity of the enzyme hexosaminidase. Each experiment was performed three times in quadruplicate. The counts were averaged for each drug concentration and mean cell count with a standard error as well as the 50% inhibitory doses (ID50s) were calculated. Photofrin demonstrated an inhibitory dose response curve (dark toxicity) to human fibroblasts. Concentrations greater than 100 micrograms/ml of photofrin alone completely inhibited cell growth. Concentrations less than 0.01 micrograms/ml did not have any effect on fibroblast proliferation. There was no significant log dose shift of the inhibitory effect of photofrin with the exposure to either sunlight or Argon laser. Photofrin may be used as a cytotoxic agent alone but does not appear to be activated by light to modulate subconjunctival fibroblast proliferation within the laser parameters used.

CI-973, a new platinum derivative with potential antileukemic activity

We examined the effects of CI-973 (supplied by Parke-Davis) on several human leukemia cell lines and a Chinese hamster ovary (CHO) line and their drug-resistant counterparts. The cell lines used were HL-60, HL-60/mAMSA, HL-60/DOX, KBM3, KBM3/mAMSA 6, KBM3/mAMSA 6(85), CHO, and CHO/AC-7. DOX, mAMSA, and AC-7 indicate resistance to doxorubicin, amsacrine, or 1-beta-D-arabinofuranosylcytosine, respectively. Cells were incubated with CI-973, and the effect was evaluated by two methods: growth inhibition assay and inhibition of colony formation. All cell lines examined were inhibited by CI-973; two of three amsacrine-resistant lines and the one cytarabine-resistant line demonstrated collateral sensitivity. At equivalent dosages, a 4-day exposure provided much greater cell kill than a 1-h exposure. Clonogenic assay showed exponential killing over 3 log units. Maximum CI-973 levels required to kill 50% of cells were 10-fold lower than the peak plasma levels achieved in a phase I solid tumor study. A continuous infusion phase I study in acute leukemia has been initiated.

Wide-angle self-aligning heterodyning with four-wave mixing

Self-aligning optical heterodyning is demonstrated with an acceptance angle as large as 40 degrees . The receiver consists of a strontium barium niobate (SBN) crystal, a detector, and collecting lenses. The incoming beam interferes with the local oscillator to create a real-time grating in the SBN crystal, which diffracts and aligns the signal with the local oscillator. Heterodyne detection occurs as long as the written grating can diffract the input signal. All alignment requirements between the signal and local oscillator are automatically satisfied by the diffraction process, which permits the large acceptance angle. Insensitivity with respect to crystal orientation and background radiation has also been demonstrated.

Localization of the highly polymorphic microsatellite DXS456 on the genetic linkage map of the human X chromosome

The CA repeat microsatellite DXS456, with a heterozygosity of 77%, has been localized by multipoint linkage analysis in relation to 20 other genetic markers. DXS456 mapped to a 4.2-cM interval defined by the flanking markers DXS178 and DXS287. The maximum likelihood order of markers, cen-(DXYS1X/DXYS13X/DXYS2X/DXYS12X)-DXS366 -DXS178-DXS456-DXS287-DXS358-DXS267- qter, is favored by odds greater than 1000:1 over the subset of most likely alternative orders. Linkage of DXS456 can be inferred for at least six disease genes that are known to be linked to markers in the region Xq21.31-Xq25 and the marker will serve as an important index point for orienting these and other disease and marker loci in the region.

Plain film of intracardiac foreign bodies: the blurring effect

We report two cases of gunshot wounds of the chest, in each of which a bullet was retained in the pericardial sac. Because the bullets appear to be out of focus, one may think they are in the cardiac chambers, but the images of bullets retained in the pericardial sac may also be blurred due to the spinning effect of the heartbeat on the bullet.

Prejunctional effects of opioids in the perfused mesentery of the rat and rabbit: interactions with alpha 2-adrenoceptors

Prejunctional effects of opioids were examined in the perfused mesentery of two species: the rat and rabbit. Use of agonists selective for subtypes of mu, delta, and kappa opioid receptors produced no effect on contractile responses to adrenergic nerve stimulation in the rat perfused mesentery, except for small effects of the kappa agonist EKC, which may be non specific. In contrast, mu, delta and kappa receptors appear to be present in the rabbit. The mu selective agonist, DAMGO, kappa agonist, ethylketocyclazocine, and delta agonists, DPDPE and [Leu5]-enkephalin, all produced significant inhibition of contractile responses to transmural nerve stimulation. The inhibitory effect was greatest for ethylketocyclazocine. To test the possibility that prejunctional activation of alpha 2 adrenoceptors with endogenous norepinephrine might decrease the activity of prejunctional opioid receptors in the rabbit, inhibitory effects of delta and kappa selective agonists were tested in the presence of 10(-7) M yohimbine. Inhibitory responses of the kappa selective agonist ethylketocyclazocine were enhanced, while that of delta selective agonists [Leu5]-enkephalin and DPDPE remained unchanged when yohimbine was present. Thus, the effects of opioids vary and depend on the tissue and receptor subtypes they act upon. Furthermore, the enhanced inhibitory effect of opioid receptor activation in the presence of yohimbine is not found for all opioid receptors.

Treatment of coronary artery stenosis and coronary arteriovenous fistula by interventional cardiology techniques

Complications associated with coronary arteriovenous fistulae (CAVF) include congestive heart failure, bacterial endocarditis, fistula rupture, and angina secondary to the "coronary steal" phenomenon. Traditional treatment of large CAVF is surgical ligation. In this report, we describe a modified microcoil embolization and guidewire technique for percutaneous closure of CAVF.

Refined physical and genetic mapping of the NF1 region on chromosome 17

A total of 15 polymorphic markers were used to construct a genetic map that encompasses the NF1 locus on chromosome 17. The markers were a subset of a large collection of chromosome 17-specific probes and were selected for marker typing in NF1 families after physical localization to the pericentric region of the chromosome. Multilocus data for a total of 17 informative NF1 families and 39 other families were included in genetic analyses. No recombination was observed between NF1 and four markers, one or more of which was informative in 86% of parents. More-refined physical mapping studies demonstrated that all four of the markers are proximal to the chromosome 17 translocation breakpoints from two NF1 patients bearing balanced translocations. The region flanking the disease locus spans a distance of 1 centimorgan (cM) in males and 9 cM in females. Close flanking markers were informative in 76% of meioses. Sex differences in recombination rates in the pericentric region were highly significant statistically.

Mapping of Alport syndrome to the long arm of the X chromosome

Five X-chromosome DNA markers were typed on 261 members of three large kindreds with Alport syndrome (hereditary glomerulonephritis). Lod scores greater than 3.0 for linkage between the disease locus and two of the markers confirmed X-linked inheritance of the disease. A decreasing gradient in the estimated recombination fractions observed when the markers were ordered on the basis of their map locations suggested that the disease locus is on the long arm distal to all the markers typed in this study. Using three-locus analysis we rejected all but three map orders for the six loci (the disease locus and five markers). In all three the Alport syndrome locus was on the long arm of the X chromosome distal to all the markers. Two types of Alport syndrome were represented in the three kindreds. Affected males in one kindred developed deafness in addition to nephritis; deafness did not occur in members of the other two kindreds. Although larger recombination-fraction estimates were obtained for all five markers in the kindreds without deafness, the difference was significant for only one marker. Evidence of heterogeneity was not found in tests using two markers. Markers distal to the disease locus are needed to determine whether two loci are responsible for the two types of Alport syndrome.

Genetic analysis of NF1: identification of close flanking markers on chromosome 17

The gene causing von Recklinghausen neurofibromatosis, or NF1, has been more precisely localized in the pericentromeric region of chromosome 17. Narrowing of the location for the disease became possible through the identification of eight new DNA probe genetic markers in the centromeric region. Markers that closely flank the centromere also closely flank the NF1 gene. Although there was evidence against this localization in one recombinant, a review of the clinical records revealed a borderline diagnosis of NF1. Significant sex differences in recombination were observed in the pericentric region, and odds for different orders were less discriminating when sex differences were considered in multilocus analyses. The location of the NF1 gene with respect to the centromere could not be determined because recombinants between NF1 and the centromere were not detected in the set of families tested.

A genomic search for linkage of neurofibromatosis to RFLPs

Our initial attempt to map NF was directed towards chromosomes 4 and 19, both of which had provided positive evidence for linkage in previous reports. This analysis showed no evidence in support of either hypothesis. Our second attempt at mapping NF was a general search of the genome, analysing a set of markers selected according to their degree of polymorphism, chromosomal location, ease of use, and availability. Data for linkage analysis were obtained from 17 multiplex families which are segregating a gene for NF. Linkage analyses were performed using PAP. Of note is the lod score of +1.17 at a recombination fraction of 0.1 between NF and the centromere of chromosome 17.

Gene for von Recklinghausen neurofibromatosis is in the pericentromeric region of chromosome 17

Linkage analysis of 15 Utah kindreds demonstrated that a gene responsible for von Recklinghausen neurofibromatosis (NF) is located near the centromere on chromosome 17. The families also gave no evidence for heterogeneity, indicating that a significant proportion of NF cases are due to mutations at a single locus. Further genetic analysis can now refine this localization and may lead to the eventual identification and cloning of the defective gene responsible for this disorder.

Perioperative and long-term results after electrophysiologically directed ventricular surgery for recurrent ventricular tachycardia

Thirty-six patients underwent ventricular aneurysmectomy and electrophysiologically directed endocardial resection for treatment of recurrent ventricular tachycardia refractory to antiarrhythmic drug therapy. The surgical mortality rate was 17% and all 30 patients discharged from the hospital were alive at the end of the follow-up period (range 6 to 54 months), yielding a cumulative projected survival rate of 83% by actuarial analysis. Poor systolic function of the nonaneurysmal ventricular segments was the strongest and the only independent predictor of operative mortality among the clinical, hemodynamic, angiographic and electrophysiologic variables analyzed by stepwise logistic regression. Ventricular tachycardia recurred early in four of the six patients in whom the endocardial resection was limited to a small area for technical reasons. Twelve patients, including 10 with sustained ventricular tachycardia still inducible by postsurgical programmed electrical stimulation, were discharged receiving antiarrhythmic drugs that had been tried unsuccessfully before surgery. During a mean follow-up period of 25 +/- 15 months, nonfatal sustained ventricular tachycardia recurred in two patients after discharge. Inadequate endocardial resection was a significant predictor of arrhythmia recurrence.

Glucose 6-phosphate dehydrogenase of calf trabecular meshwork

Activities of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase of calf trabecular meshwork were measured and found to be 0.23 and 0.47 mumole/min/g tissue, respectively. Glucose 6-phosphate dehydrogenase was purified 450-fold with a yield of 91% by anion exchange chromatography and 2',5'-ADP agarose affinity chromatography. It was activated by Ca2+, Mg2+, and Mn2+. It was deactivated by p-chloromecuribenzoate, p-chloromercuribenzene sulfonate, and iodoacetamide, but this deactivation could be prevented by pretreatment with cysteine or glutathione. Its rate was regulated by the NADPH/NADP+ ratio, being maximal at a ratio of 0, and negligible at a ratio of 10. At the physiological ratio of 5, its rate was approximately half maximal. On disc gel electrophoresis of both the crude and purified enzyme, seven bands of glucose 6-phosphate dehydrogenase activity could be seen. The isozyme pattern was similar to that of calf retina, but different from that of calf liver. These data suggest that trabecular meshwork is well supplied with the capacity to generate NADPH. Typical demands for NADPH may be to detoxify H2O2 and/or organic peroxides through the glutathione peroxidase/glutathione reductase system, and both generating and removing products of the "killing reaction" during phagocytosis.

Domain structure of vitronectin. Alignment of active sites

The structure of vitronectin, an adhesive protein isolated from human plasma, was studied by chemical fragmentation. Partial cleavage of vitronectin with cyanogen bromide in 70% formic acid generated four main fragments with masses of 53,000, 43,000, 35,000, and 12,000 daltons arising from both the 75- and 65-kDa vitronectin polypeptides and a 10-kDa fragment arising only from the 75-kDa polypeptide. By varying the reaction conditions, four BrCN cleavage sites and one acid cleavage site could be identified. The latter site gave rise to 40-, 32-, and 26-kDa fragments. The order of these fragments within the vitronectin polypeptides was determined by comparison of the NH2-terminal sequences of the polypeptides and their fragments, by further cleavage of the largest fragments with BrCN or 70% formic acid, and by assaying for heparin-binding and cell-attachment activities. The NH2-terminal sequences of the intact vitronectin polypeptides are the same and identical to a 44-amino acid serum peptide called somatomedin B, indicating that vitronectin may be the precursor of somatomedin B. The cell-attachment site appears to be located within approximately 5 kDa of the NH2 terminus, but it is distinct from the somatomedin B domain. The heparin-binding site is contained in the 12-kDa fragment near the COOH terminus. This fragment was shown to bind to a chondroitin sulfate proteoglycan in addition to heparin. The NH2-terminal amino acid sequence of this glycosaminoglycan-binding fragment is remarkably rich in basic amino acids. The NH2-terminal sequences of this and the other vitronectin fragments showed no homology with the amino acid sequence of the heparin-binding domain of fibronectin or other known sequences from fibronectin. These results show that the biological activities of vitronectin are located in distinct parts of both of the vitronectin polypeptides, which appear to be identical except for the presence of an additional 10-kDa fragment near or at the COOH terminus of the 75-kDa polypeptide.

Comparison of the cardiopulmonary effects of etomidate and thiamylal in dogs

The cardiopulmonary effects of etomidate, a nonbarbiturate, short-acting, IV anesthetic, were compared and contrasted with those of thiamylal sodium in chronically instrumented conscious dogs. Etomidate, when administered IV at dosages of 1.5 and 3.0 mg/kg of body weight, produced anesthesia lasting from 8 +/- 5 and 21 +/- 9 minutes, respectively. Heart rate, aortic blood pressure, left ventricular peak pressure, left ventricular end diastolic pressure, left ventricular contractile force, and myocardial oxygen consumption were unchanged after administration of either dose of etomidate; however, the dosage of 1.5 mg/kg produced significant (P less than 0.05) increases in respiratory rate and decreases in tidal volume. The minute volume remained unchanged from base-line values. Significant (P less than 0.05) decreases in tidal volume, arterial pH, and partial pressure of oxygen were produced, and minute volume remained unchanged when 3.0 mg of etomidate/kg of body weight was administered. Thiamylal sodium (8.0 mg/kg of body weight; given IV) produced anesthesia lasting for 14 +/- 5 minutes. Significant increases (P less than 0.05) in heart rate, arterial blood pressure, left ventricular peak pressure, and myocardial oxygen consumption were observed after IV administration. Left ventricular contractility was significantly (P less than 0.05) decreased. Respiratory rate was not significantly (P less than 0.05) affected by thiamylal although tidal volume and minute volume were decreased. These respiratory alterations resulted in significant (P less than 0.05) increases in the arterial partial pressure of carbon dioxide and decreases in pH and the partial pressure of oxygen. On the basis of cardiopulmonary function, etomidate offered rapid, safe, short duration anesthesia superior to that of thiamylal sodium.