Selective modification by transglutaminase of a glutamine side chain in the hinge region of the histidine-388----glutamine mutant of yeast phosphoglycerate kinase

The transglutaminase-catalysed incorporation of putrescine and monodansylcadaverine into yeast phosphoglycerate kinase has been studied. There is little incorporation of the amines into wild-type enzyme, but nearly stoichiometric incorporation into the histidine-388----glutamine mutant enzyme. C.d. studies show that the overall structure of the mutant enzyme is very similar to that of the wild-type enzyme. Incorporation of the amines into the mutant enzyme causes no significant change in its activity. Glutamine-388 was shown, by isolation and sequencing of the modified peptide, to be the site of incorporation of monodansylcadaverine into the mutant enzyme. The specificity of the transglutaminase reaction is discussed in the light of available data.

Phase II trial of Bisantrene for metastatic melanoma: an Illinois cancer council study

Sixteen patients with metastatic melanoma entered this phase II study of the efficacy of monthly cycles of Bisantrene. Toxicity was characterized by leukopenia, resulting in the hospitalization of one patient for a febrile incident, and superficial phlebitis. The results were similar to those of previous studies, in that among the 13 patients evaluable for response (six previously untreated with chemotherapy) there were no responses.

Leishmania mexicana complex: human infections in the Republic of Panama

Parasites of the genus Leishmania responsible for human cutaneous leishmaniasis in the New World form 2 major taxonomic divisions: the Leishmania braziliensis and the L. mexicana complexes. We report the isolation and characterization of the L. mexicana complex among humans in the Republic of Panama. Characterization was based on parasite morphology, pathogenesis in infected golden hamsters, cellulose acetate isoenzyme electrophoretic mobilities, and membrane-specific monoclonal antibodies using the radioimmune binding assay technique.

Purification and characterization of catalytic fragments of phosphorylase kinase gamma subunit missing a calmodulin-binding domain

A catalytic fragment preparation of rabbit muscle phosphorylase kinase produced by limited chymotryptic digestion was isolated and identified as the NH2-terminal region of the gamma subunit by Edman degradation. Mass spectral analysis, gas phase sequence analysis, and amino acid analysis of the active fragment carboxyl-terminal peptides revealed multiple COOH termini generated at residues Tyr290, Arg296, and Phe298 in the gamma subunit sequence. These active fragment species are about 24% smaller than the gamma subunit (Mr 44,673) and range in size from Mr 33,279 to Mr 34,275. The active fragment preparation exhibits a specific activity about 6-fold higher than that of the gamma subunit-calmodulin complex. Calmodulin confers calcium sensitivity to the gamma subunit but has no effect on the enzymatic properties of active fragment. Affinity measurements demonstrated a dissociation constant of 0.7 microM for active fragment binding to dansylcalmodulin, a value about 28-fold weaker than reported for the gamma subunit. These data support the presence of a calmodulin binding domain in the COOH-terminal region of the gamma subunit.

Radiologic evaluation of penetrating aortic atherosclerotic ulcer

Patients with penetrating atherosclerotic ulcers of the aorta present with back or chest pain that mimics classic aortic dissection. The pathologic findings, however, are distinctly different from those of aortic dissection in that an atherosclerotic lesion with ulceration penetrates into the internal elastic lamina, allowing hematoma formation within the media of the aortic wall. This may lead to false aneurysm or, rarely, transmural rupture of the aorta. Imaging findings of penetrating aortic atherosclerotic ulcers are also different from those of classic aortic dissection. We have found computed tomography to be especially useful in differentiating between these entities and present several illustrative cases.

Structural characterization of the rat seminal vesicle secretion II protein and gene

The gene encoding rat seminal vesicle secretion II (SVS II) protein has been cloned from a rat genomic DNA library using a cDNA probe generated from rat dorsal prostate androgen-dependent mRNA. The cloned 7.3-kilobase pair genomic fragment contains approximately 5000 base pairs (bp) of the 5'-flanking region and the entire coding region of the SVS II protein within two exons. A sequence of 4156 bp of the rat SVS II gene has been determined, including 2037 bp of the 5'-flanking region, exon 1 (95 bp), intron 1 (236 bp), exon 2 (1171 bp), and 614 bp of the 3'-flanking region. The 5'-flanking region contains three conserved elements found in other seminal vesicle secretion genes (SVS IV-VI proteins) within 250 bp of the transcription start site as well as a glucocorticoid response element at position -314 in the SVS II gene. The first exon encodes a 22-amino acid leader peptide plus the first 2 amino acids of the secreted protein. The second exon encodes the remaining amino acids in the SVS II protein sequence. The mature protein contains 392 residues and has an Mr of 43,116. Concomitant with the gene analysis, the rat SVS II protein was purified to homogeneity, and 333 residues (85%) of the amino acid sequence were determined by automated Edman degradation. The DNA-deduced sequence and that determined by direct analysis of the protein are in complete agreement. The blocked NH2-terminal amino acid was identified as pyroglutamic acid by mass spectrometry and aminopeptidase digestion. A 13-residue structure with the consensus sequence GSQLKSFGQVKSS is repeated 13 times within the SVS II protein and appears to be involved in the formation of the rat copulatory plug via a transglutaminase reaction cross-linking glutamine and lysine residues. Overall, the SVS II protein sequence exhibits little structural relatedness to any other known protein sequence; however, some similarity can be found between the 13-residue repeat and another repeating structure and apparent transglutaminase substrate in the guinea pig seminal vesicle clotting protein.

Electrophoretic purification of the alpha and beta subunits of phosphorylase kinase and evidence in support of the deduced amino acid sequences

A simple, rapid sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method is presented for isolating the alpha, alpha' and beta subunits of rabbit muscle phosphorylase kinase. The SDS-PAGE procedure can yield milligram amounts of alpha and beta from a single preparative gel and also allows isolation of the alpha' isozyme free of alpha. Notably the method provides the purified subunits in a form amenable to structural analysis. Edman degradation of alpha and alpha' reveal identical NH2-terminal structures. Amino acid analysis of the electrophoretically purified alpha and beta subunits are in good agreement with their deduced primary structures. The amino acid sequence of 488 residues in alpha and 713 residues in beta were determined by gas phase Edman degradation. The data support the recently deduced primary structures of alpha (Zander et al., Proc. Natl. Acad. Sci. USA, 1988, 85, 9381-9385).

Identification of Staphylococcus aureus binding proteins on isolated porcine cardiac valve cells

Infective endocarditis caused by Staphylococcus aureus may be initiated by bacterial binding to cardiac valve cells. We investigated binding of whole S. aureus organisms to preparations of isolated porcine cardiac valve proteins. Cultured endothelial and subendothelial cells were surface labeled with iodine 125. After preabsorption with Escherichia coli, an organism that only rarely causes infective endocarditis, binding of surface proteins to S. aureus was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent autoradiography. The results showed that cardiac valve endothelial cells expressed a major S. aureus-binding protein with an approximate apparent molecular weight of 120,000. In contrast, cardiac valve subendothelial cells expressed on their surface a single species of binding protein with an approximate apparent molecular weight of 220,000; immunoblot analysis suggested that this protein was fibronectin. We also used radiolabeled S. aureus to probe cellular proteins transferred to nitrocellulose membranes. This technique identified a 125,000 molecular weight protein that bound S. aureus in endothelial cell extracts. We conclude that specific S. aureus binding to cardiac valve cells is mediated by different receptors for endothelial and subendothelial cells.

Phase II trial of 4' deoxydoxorubicin (DXDX) for unresectable non-small cell bronchogenic carcinoma. An Illinois Cancer Council study

A phase II trial of 4' Deoxydoxorubicin (DXDX) was conducted in unresectable previously untreated non-small cell lung cancer patients. DXDX was administered every 3 weeks by short intravenous infusion at a starting dose of 30 mg/m2, with dose escalation to 40 mg/m2 toxicity permitting. Four responses, all partial, were observed in 35 evaluable patients, for a response rate of 11% (95% confidence limits 3.2% and 26.7%). Myelosuppression was the dose-limiting toxicity. Cardiotoxicity was not seen. DXDX has minimal activity against non-small cell lung cancer as a single agent at the dosage used in this study.

[Blister dermatitis caused by Epicauta flagellaria (Erichson) (Coleoptera: Meloidae) species]

This paper is the first published report of vesicular dermatitis due to blister beetles of the family Meloidae in Panamá. A familial outbreak of bullous dermatitis caused by Epicauta flagellaria (Erichson) is described. All previous cases known in the Gorgas Memorial Laboratory were associated with E. isthmica Werner. Bullous lesions are produced when cantharidin, a vesicating toxin contained in the beetle's body, is released at the time the insect is crushed or rubbed upon the exposed skin. Rules for the treatment and prevention of this disease are indicated.

Presence of antibodies in the sera of patients with Graves' disease recognizing a 23 kilodalton fibroblast protein

We examined whether antibodies (present in sera from patients with Graves' disease) might be directed against a connective tissue cellular component of the anatomical regions affected in the peripheral manifestations of that disease. Accordingly, we performed immunoblot analyses of cultured retroocular and pretibial fibroblasts. Retroocular connective tissue was obtained during orbital decompression surgery (n = 7) and at autopsy from normal individuals (n = 2). Pretibial skin biopsies were obtained from patients with pretibial dermopathy (n = 3) and at autopsy (n = 2). In addition, biopsies from other regions [extraocular muscle (n = 6), thyroid (n = 2), and abdominal skin (n = 3)] were also collected at surgery or autopsy. Serum samples were obtained from patients with severe Graves' ophthalmopathy (n = 31), hyperthyroid Graves' disease without overt ophthalmopathy (n = 13), nodular thyroid disease (n = 7), Hashimoto's thyroiditis (n = 7), rheumatoid arthritis (n = 5), and systemic lupus erythematosus (n = 3) and from normal individuals (n = 33). Electrophoresed fibroblast proteins were immunoblotted with 1:100 dilutions of sera using an antihuman immunoglobulin G-alkaline phosphatase conjugate. Antibodies against a 23kDa fibroblast protein were present in the sera from 24 of 44 (56%) of patients with Graves' disease with or without ophthalmopathy, 0 of 7 nodular thyroid disease, 0 of 7 Hashimoto's thyroiditis, 0 of 5 rheumatoid arthritis, 0 of 3 systemic lupus erythematosus, and 5 of 33 (15%) normal subjects. Significant differences in the observed frequency of antibodies existed between the Graves' disease group and the normal control group (P less than 0.01) or those patients with the other conditions (P less than 0.01). This 23kDa antigen was apparent in fibroblasts derived from individuals with Graves' disease as well as normal individuals and was present in fibroblasts from all anatomical sites studied. It was the sole protein uniquely recognized by sera from patients with Graves' disease. However, this serum reactivity did not appear to be related to the presence of clinically overt ophthalmopathy or pretibial dermopathy. Subcellular localization studies disclosed that the antigen was present in the supernatant but not the pellet resulting from a 100,000 x g centrifugation of whole cell sonicates. Antibodies against a 23kDa fibroblast protein are present in the majority of sera from patients with Graves' disease and rarely in sera from either normal individuals or those with other thyroid disorders or autoimmune diseases. Our results suggest the possibility that antibodies directed against this fibroblast antigen may be related to the developm

Treatment of American cutaneous leishmaniasis with orally administered allopurinol riboside

Eighteen patients received 1,250 mg of allopurinol riboside (AR) four times daily for 28 d. Nine of the patients concurrently received 500 mg probenecid (PB) four times daily. Cure was assessed clinically and parasitologically. Patients who had culture-positive and nonhealing lesions 3 mo after therapy received pentavalent antimony. Of the nine patients who received AR alone, four (44%) had clinical improvement at the end of therapy and two (22%) were culture-negative. A third patient became culture negative at 2 mo after therapy. The culture-negative patients were completely healed at 1 mo and remained so at 1 y after therapy. Of the nine patients who received AR plus PB, four had complete healing and two had clinical improvement at the end of therapy; however, all patients remained culture-positive. At 2-3 mo after therapy, six (67%) of the patients were completely healed, and of these, five (56%) were culture-negative. The drug was well-tolerated.

Phase II trial of spirogermanium in advanced non-small cell lung cancer. An Illinois Cancer Council Study

A phase II trial of spirogermanium was conducted in advanced previously untreated non-small cell lung cancer patients. The drug was given by intravenous infusion 3 times per week for 2 weeks, twice per week for the next 2 weeks, and then weekly. Starting dose was 125 mg/m2, and dose escalation of 25 mg/m2 per week was required in the absence of toxicity to a maximum dose of 200 mg/m2 per infusion. Fifteen eligible patients were treated, and no objective responses were seen. Primary toxicity was neurologic and reversible after withdrawal of the drug. We conclude that spirogermanium is not active against non-small cell lung cancer in the dosage used in this study.

Reaction of fluorescein isothiocyanate with an ATP-binding site on the phosphorylase kinase alpha subunit

Phosphorylase kinase can be labeled specifically on the alpha subunit with fluorescein 5'-isothiocyanate (FITC) which concomitantly inactivates the enzyme (T. G. Sotiroudis and S. Nikolaropoulus (1984) FEBS Lett. 176, 421-425). Labeled peptides have been purified and their primary structure has been determined. The amino acid sequence of the fluorescein-labeled tryptic peptide is Lys-Met-Gln-Asp-Gly-Tyr-Phe-Gly-Gly-Ala-Arg. The environment of this fluorescein-labeled lysine has been determined by sequencing peptides isolated from a Staphylococcus aureus V8 digest and two further cyanogen bromide fragments of the purified [14C]carboxymethylated alpha subunit. The partial sequences obtained have then been localized in the primary structure of the alpha subunit [Zander et al. (1988) Proc. Natl Acad. Sci. USA 85, 2929-2933]. Both the incorporation of the fluorescent label and enzymatic inactivation are inhibited by ATP only at pH 7.0; ADP and AMP do not protect. Kinetic analysis reveals a competition between ATP and FITC; a Ki for ATP of 728 +/- 100 microM has been determined.

Castor-oil induced diarrhoea in ponies: a model for acute colitis

A reproducible, reversible model of colitis induced in ponies by administering castor oil (2.5 ml/kg bodyweight [bwt] per os) was characterised by abdominal pain, fever, watery diarrhoea, dehydration, hypovolaemia, toxaemia, leucopenia, decreased serum Cl, Na and K levels and metabolic acidosis. The signs were most severe between 24 and 48 h post induction, stabilisation was frequently observed after 72 h, although diarrhoea could persist beyond 96 h. Morphological and in vitro transport studies (right ventral colon) were conducted on tissues from animals destroyed at 24, 48 and 72 h. In the caecum and colon, surface epithelial disruption and exfoliation from the basement membrane occurred between 24 and 48 h. Early signs of recovery were evident by replenishment of denuded areas with columnar epithelium at 72 h. The crypt epithelium was unaffected throughout the intestinal tract. In vitro transport studies were consistent with the morphological findings. Decreased Na-Cl absorption and normal Cl secretion indicated an impaired surface epithelium coincident with an undamaged cryptal epithelium. Increased mucosal permeability was demonstrated by high ionic conductance and large unidirectional isotopic fluxes. Tissue conductance improved during in vitro incubation suggesting epithelial repair after removal of castor oil. Changes in the population and proportion of bacteria in the faeces as diarrhoea ensued were confirmed at necropsy with a predominance of E. coli and Enterobacter/Klebsiella sp in the large bowel. The experimental induction of castor oil colitis showed many similarities to intestinal endotoxaemia and the secretory type diarrhoea encountered in naturally occurring acute colitis syndromes in horses. The model could prove applicable in studying the pathophysiological mechanisms precipitating such life-threatening disorders.

Insulin resistance in uremia: an in vivo and in vitro study

Insulin-mediated glucose metabolism was examined in vivo and in vitro in a chronically uremic (4-week) rat model established by a 90% nephrectomy. Using the euglycemic insulin clamp technique, uremic rats demonstrated a 28% reduction (P less than .01) in total body glucose disposal compared with pair-fed controls. Suppression of hepatic glucose production by insulin was not impaired. The ability of insulin to promote glycogen synthesis by the soleus muscle in vitro was normal in uremic rats. In contrast, the ability of insulin to enhance both glycolysis and glucose oxidation by the soleus muscle was significantly reduced (P less than .01) in uremic rats. These results provide evidence that at least two intracellular metabolic defects, ie, in the glycolytic and glucose oxidative pathways, contribute to the insulin resistance of chronic uremia.

CT-guided biopsy: prospective analysis of 1,000 procedures

The authors prospectively analyzed 1,000 biopsies guided with computed tomography (CT) and performed in 955 patients over a 30-month period. All patients were followed up from 3 months to 2 years. The biopsies were performed in an average of 22 minutes (range, 3-85 minutes) by 26 different radiologists; five radiologists performed 547 of the procedures. Of the 1,000 biopsies, 722 were performed in areas in the liver, retroperitoneum, pancreas, pelvis, and adrenal glands. Of 69 errors in diagnosis, 67 were falsely negative and two were falsely positive; 747 true-positive and 184 true-negative diagnoses were made. CT-directed biopsy for accurate diagnosis was 91.8% sensitive and 98.9% specific, with a positive predictive value of 99.7% and a negative predictive value of 73.3%. Of 11 patients with complications, seven had hematomas, three had pneumothorax, and one had hematuria. No deaths occurred, and only one patient required surgery.

O-acetyl-salicylic acid promotes colony formation from protoplasts of an elite maize inbred

The salicylic acid derivative acetylsalicylic acid (ASA) was found to promote colony formation from protoplasts isolated from embryogenic suspension cultures of an elite maize inbred line. The drug was most effective at concentrations of 30-100 mg/l, and increases of more than 20-fold in the number of colonies recovered from protoplasts were obtained. The rate of growth of protoplast-derived cell colonies was not affected.

The complete primary structure of the cellular retinaldehyde-binding protein from bovine retina

Cellular retinaldehyde-binding protein (CRALBP) carries 11-cis-retinol and 11-cis-retinaldehyde as endogenous ligands and may be a functional component of the visual cycle. The complete amino acid sequence of CRALBP from bovine retina has been determined by direct microanalysis of the protein. Bovine CRALBP contains 316 residues in a single amino-terminal-blocked chain corresponding to a molecular weight of 36,421, inclusive of the blocking group. Overlapping peptides were generated by cleavage of lysyl, arginyl, methionyl, glutamyl, and one tryptophanyl bond and sequenced by gas-phase Edman degradation. Analysis of amino-terminal arginyl and methionyl peptides by fast atom bombardment mass spectrometry identified the N alpha-blocking group as an acetyl moiety, and tandem mass spectrometry provided the sequence of the first 9 residues. Comparison of CRALBP with other known protein sequences reveals no significant structural relatedness. The present results provide a basis for relating CRALBP domains with physiological function and for the future development of a more detailed three-dimensional model of the interaction of 11-cis-retinaldehyde with protein.

The large flap sculptured facelift

The large flap sculptured facelift is a redraping rather than a pinching or pulling operation. The skin flaps are redraped over the tightened, sculptured underlying fat-musculoaponeurosis. This procedure can be performed on a majority of patients with minimal complications.

Successful treatment of pulmonary embolism and associated mobile right atrial thrombus with use of a central thrombolytic infusion

Patients with pulmonary embolism and two-dimensional echocardiographic evidence of right atrial thrombus have a high mortality rate despite standard anticoagulation therapy. We used a direct central infusion of streptokinase in three such patients, who subsequently had rapid and complete clinical improvement. In this setting, thrombolytic therapy should be considered an effective therapeutic option.

Platelet adherence to cardiac and noncardiac endothelial cells in culture: lack of a prostacyclin effect

Cardiac tissues show a propensity to develop nonbacterial thrombotic endocarditis, a meshwork of platelets and fibrin. This lesion may cause a predisposition to subsequent colonization by circulating microorganisms, leading to infective endocarditis. We measured platelet adherence in vitro to cultured endothelial cells derived from the porcine aortic valve and ascending aorta. We found that valvular endothelial cells showed a twofold to threefold higher adherence than ascending aortic endothelial cells of chromium 51-labeled platelets in the presence of proteolytically active thrombin. This finding did not correlate with endothelial prostacyclin release: cardiac valve endothelial cells released more prostacyclin than did, ascending aortic cells, exogenous prostacyclin had no effect on thrombin-stimulated adherence, and aspirin inhibition of endothelial prostacyclin synthesis showed no effect on platelet adherence. Fixation of platelets abolished thrombin-stimulated adherence; fixation of endothelial cells had minimal effect. We suggest that these differences may contribute to the propensity of the cardiac valve to develop nonbacterial thrombotic endocarditis.

Specific binding of Staphylococcus aureus to cultured porcine cardiac valvular endothelial cells

Infective endocarditis usually occurs in patients who have had previous cardiac damage or who have congenitally abnormal hearts. However, this infection may afflict otherwise normal individuals, and it is often caused by Staphylococcus aureus. In these individuals, interactions between circulating microorganisms and resident cardiac endothelial cells may initiate the infection. In the present studies we established an assay to measure in vitro binding of S. aureus to porcine cardiac valve endothelial cells. We found that this interaction was specific and saturable with respect to time. In contrast, there was no specific binding of Escherichia coli, an organism that rarely causes endocarditis. Exogenous fibronectin had no effect on specific binding of S. aureus, and heat-killed organisms adhered equally well as viable bacteria. Fixation of the endothelial cells with formalin abolished all specific binding. Soluble components from bacterial extracts inhibited S. aureus binding in dose-dependent fashion. These observations suggest that circulating S. aureus may interact with specific sites on cardiac endothelial cells, thereby potentially initiating infective endocarditis.

Glycoproteins synthesized by cultured cardiac valve endothelial cells: unique absence of fibronectin production

We have previously reported that cultured porcine cardiac valve endothelial cells released less fibronectin into the culture supernatant when compared to other porcine endothelial cells. In this report we compared the spectrum of glycoproteins synthesized by cardiac valve endothelial cells to glycoproteins synthesized by comparison endothelial cells derived from the ascending thoracic aorta. The cells were endogenously radiolabeled and extracted with detergent. Glycoproteins in the cell extracts were then isolated on wheat germ lectin-agarose and compared using autoradiography following polyacrylamide gel electrophoresis. Fibronectin was identified by immunoblotting with specific antibody. The results showed that the outstanding difference between the endothelial cell types was the virtual absence of fibronectin in the cardiac valve endothelial cell extract.

Do metal ions promote the re-activation of the 2,3-bisphosphoglycerate-independent phosphoglycerate mutases?

It has been reported [Smith, McWilliams & Hass (1986) Biochem. Biophys. Res. Commun. 136, 336-340] that addition of certain metal ions, notably Co2+ and Mn2+, promoted the refolding of denatured phosphoglycerate mutase from wheat germ. We have re-investigated these experiments and have shown that, when precautions are taken to avoid artefacts in the assay system, the metal ions do not promote any re-activation of the denatured wheat-germ or Aspergillus nidulans enzymes. An alternative explanation is offered for the observations of Smith et al. (1986).

Percutaneous placement of the Greenfield vena caval filter

During the period from August 1986 to August 1987, 50 patients underwent percutaneous placement of a Greenfield vena caval filter from the right femoral vein, left femoral vein, or right internal jugular vein at our institution. All 50 patients had a contraindication to anticoagulation therapy or had complications of anticoagulation for deep venous thrombosis or pulmonary emboli. The percutaneous placement was accomplished in the angiographic suite with use of local anesthesia and was well tolerated by all patients. Only three complications related to the percutaneous approach occurred during the short-term follow-up (3 months to 1 year). These complications were deep venous thrombosis of the leg in two patients and misplacement of the filter in one patient. The three patients tolerated these complications well. We conclude that placement of Greenfield vena caval filters can be readily accomplished by means of percutaneous entry. Our experience demonstrated minimal associated morbidity and no mortality.

Reducing nocturnal awakening and crying episodes in infants and young children: a comparison between scheduled awakenings and systematic ignoring

Infants and toddlers (N = 33) exhibiting spontaneous awakening and crying episodes during the night were randomly assigned to one of three groups: scheduled awakenings, systematic ignoring or control. Scheduled awakenings consisted of a parent arousing and feeding or consoling the child 15 to 60 minutes before typical spontaneous awakenings. Once spontaneous awakenings were precluded, scheduled awakenings by parents were gradually eliminated. Systematic ignoring consisted of allowing the child to "cry it out" without parental attention except to ensure physical well-being of their child. Children in the scheduled awakening group and the systematic ignoring group awoke and cried less frequently than children in the control group during 8 weeks of treatment and during two follow-up checks, 3 and 6 weeks after treatment. Systematic ignoring was found to be more effective than the scheduled awakenings condition during 1 week of treatment; otherwise effects of the two conditions were similar. Implications of the use of these treatment procedures are discussed.

In vivo glucose metabolism in the awake rat: tracer and insulin clamp studies

The goals of this study were twofold: (1) to determine the in vivo dose-response relationship in the conscious, unstressed rat between the plasma insulin concentration and total body glucose uptake, and between plasma insulin and suppression of endogenous glucose production; and (2) to develop a physiologic compartmental model to describe the kinetics of plasma glucose in the rat in the basal state. In order to perform repeat insulin clamp studies in the same rat, chronic catheters were implanted in the aortic arch (via the carotid artery) and in the cardiac atrium (via the jugular vein), exteriorized, and fixed to the back of the skull with a dental cement cap. Insulin was infused at rates of 1.2, 2.4, 4.8, 12, and 24 mU/min.kg, and the plasma glucose was held constant at the basal level by a variable glucose infusion (euglycemic insulin clamp). The resulting steady-state plasma insulin concentrations ranged from 40 to 1,300 microU/mL. The dose-response curve for glucose uptake was sigmoidal in shape: in the basal state, total glucose utilization averaged 6.8 mg/min.kg at an insulin concentration of 9 microU/mL, half-maximal glucose uptake (18.3 mg/kg.min) occurred at a plasma insulin concentration between 70 and 80 microU/mL, and maximal uptake (36.6 mg/kg.min) was seen at an insulin level in excess of 100 microU/mL. Residual endogenous glucose production was evaluated by a prime-continuous infusion of (3-3H)-glucose. The dose-response curve for suppression of endogenous glucose output also was sigmoidal.(ABSTRACT TRUNCATED AT 250 WORDS)

Porcine cardiac valvular subendothelial cells in culture: cell isolation and growth characteristics

We established culture lines derived from the subendothelial region of the porcine aortic valve. These cells were isolated by extensive collagenase digestion of valvular tissue and were serially propagated with stable morphology. In sparse culture, valve subendothelial cells resembled skin fibroblasts. When confluent, the valve subendothelial cells formed ridges and piles similar to vascular smooth muscle cells. Endogenous in vitro labeling experiments using 35S-methionine showed that valve subendothelial cells synthesized and released several proteins not observed in parallel experiments using porcine skin fibroblasts and smooth muscle cells. Mitogen assays using media conditioned by porcine aortic valvular endothelial cells showed that the valve subendothelial cells, when compared to skin fibroblasts and smooth muscle cells, were particularly avid responders to the growth factors released by valve endothelial cells in vitro. The valve subendothelial cells also released 10-fold more prostacyclin in response to arachidonate than did skin fibroblasts or smooth muscle cells. We conclude that valve subendothelial cells show features that distinguish them from other cultured mesenchymal cells, and that this culture system will be useful for studies of the cellular basis of valvular heart disease.

Antibiotic therapy for severe infections in infants and children

In infants and children, drug absorption, distribution, metabolism, and excretion may differ considerably from these factors in adults; thus, differences also exist in therapeutic efficacy and toxicity of various antibiotics. Because of known toxicity, certain drugs--such as chloramphenicol in high doses, the sulfonamides, and tetracycline--should not be used in neonates. Antibiotic therapy should be modified in neonates because of biologic immaturity of organs important for the termination of drug action. Because of poor conjugation, inactivation, or excretion, the serum concentrations of many antibiotics may be higher and more prolonged in neonates than in older infants. Thus, the dosages of many antibiotics must be lower and the intervals between administration must be longer. The appearance of strains of ampicillin-resistant Haemophilus influenzae, the slow development of resistance to chloramphenicol among gram-negative and gram-positive bacteria, and the development of improved analytic methods to measure chloramphenicol have all resulted in the use of this drug in select cases of serious infection in children beyond the neonatal age. Third-generation cephalosporins have an important role in empiric treatment of pediatric bacterial meningitis because of their ability to penetrate the central nervous system and their effectiveness against ampicillin- or chloramphenicol-resistant Haemophilus strains and against many gram-negative bacteria in the Enterobacteriaceae group.

Human retroocular fibroblasts in vitro: a model for the study of Graves' ophthalmopathy

Orbital connective tissue and extraocular muscles are histologically abnormal in patients with Graves' ophthalmopathy (GO). Although extraocular muscles have been extensively studied as a target for autoimmune attack in the disease, no system has been available to study retroocular fibroblasts in GO. We developed a technique to isolate fibroblasts from minced explants of connective tissue removed in the course of transantral orbital decompression surgery for GO. Postmortem specimens from individuals without evidence of thyroid disease were obtained from the same anatomical site. Confluent cells could be passaged at least 10 times with stable morphology and frozen with greater than 75% viability. An enzyme-linked immunosorbent assay was used to study the in vitro binding of serum immunoglobulin G (IgG) to these cells. We found no difference in the degree of specific binding between GO cells and cells from normal individuals. However, there was significantly greater binding of IgG from GO sera than of that from normal serum to retroocular GO fibroblasts. These results suggest that serum IgG autoantibodies against normal retroocular fibroblasts are present in some GO patients.

Denaturation and renaturation of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe

The denaturation by guanidinium chloride of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe was studied. The loss in activity broadly parallels the changes in protein structure detected by fluorescence and c.d. Renaturation can be brought about by dilution of the denaturing agent. These processes were compared with those in the enzymes from baker's yeast and rabbit muscle, which are tetrameric and dimeric respectively. The effects of the cofactor 2,3-bisphosphoglycerate on the structure and stability of the S. pombe enzyme were also investigated.

Effects of cefonicid and other cephalosporin antibiotics on male sexual development in rats

The purpose of this study was to determine whether cefonicid, a cephalosporin antibiotic with a modified N-methylthiotetrazole (MTT) side chain, caused testicular toxicity when subcutaneously administered to Sprague-Dawley male rats from days 6 to 36 postpartum at doses of 50 to 1,000 mg/kg per day. Moxalactam (a cephamycin antibiotic which will be referred to as a cephalosporin for convenience throughout), which contains the MTT side chain, was used as a positive control and was administered at 100 to 1,000 mg/kg per day, and cephalothin, which lacks an MTT side chain, was used as the negative control at 1,000 mg/kg per day. Moxalactam caused a significant reduction in testicular and seminal vesicle weights in 37-day-old animals, and histological examination revealed bilateral multifocal atrophy of the seminiferous tubules at all dose levels. Animals reared to reproductive maturity had significant deficits in fertility, and histological examination revealed multifocal or diffuse atrophy of the seminiferous tubules at all doses with a severity greater than that observed in the 37-day-old animals. The histological findings were confirmed by marked reductions in testicular sperm production rates and cauda epididymal sperm numbers. Cephalothin and cefonicid had no treatment-related adverse effects on the sexual maturation of prepubertal, juvenile, or adult males. The absence (in cephalothin) or modification (in cefonicid) of the MTT side chain was not associated with adverse reproductive effects. The relevance of these findings to humans in prenatal and prepubertal stages of life cannot be determined at this time.

Rotational delivery with Kielland's forceps

A retrospective study over 15 months showed that 10.7% of primigravid women and 1.6% of multigravid women were delivered by Kielland's forceps: a total of 145 babies. The successful vaginal delivery rate for attempted Kielland's forceps was 96.7%. The neonatal outcome was good and there were no perinatal deaths. Traumatic injuries were present in 7.6% of babies and were minor. The data show that even in the presence of fetal distress, Kielland's forceps can be safely employed for rotational delivery from the mid-pelvic cavity. This approach can avoid some caesarean sections without undue risk to the baby, the caesarean rate being 9.5%. As 10.7% of primigravid women required rotational delivery with Kielland's forceps, it is desirable that primigravid women should be cared for by obstetricians who are skilled in the use of the instrument, in order to maintain a low caesarean section rate in this group, with a good neonatal outcome.

Percutaneous transluminal angioplasty in the lower extremities: a 5-year experience

From January 1979 to March 1984, percutaneous transluminal angioplasty (PTA) was used to treat 148 limbs of 135 Mayo Clinic patients with occlusive arterial disease of the lower extremities. The procedure was technically successful in more than 95% of the attempts. The outcome was clinical improvement in 89 limbs and no improvement in 40 limbs; in 19 limbs, PTA was technically successful but the patient was dismissed from the hospital and lost to follow-up before the extent of improvement could be determined. Mean ankle/brachial pressure indices increased after PTA in those with clinical improvement but not in those without improvement. Clinical improvement was less likely to follow PTA in patients with advanced age, diabetes, severe initial symptoms, low ankle/brachial indices, or distal occlusive disease. In patients with improvement after PTA, the mean follow-up period was 33 months; during that time, failure (defined as recurrence of the original symptoms or the need for repeat PTA or operation) occurred at a rate of 6.4% per year. Serious complications occurred after three procedures (2.0%). We conclude that PTA is technically feasible and generally safe for many patients with occlusive arterial disease of the lower limbs.

Drapanas shunt using a spiral saphenous vein graft

An alternative technique for creation of a Drapanas shunt was used in a 12-year-old boy with upper gastrointestinal bleeding. Dissatisfaction with available prosthetic grafts and the inherent limitations of other autogenous materials led to the use of a spiral saphenous vein graft to bridge the superior mesenteric vein and the inferior vena cava. Patency of the graft was demonstrated 1 year postoperatively, and the patient has not had further bleeding episodes for 2 years postoperatively. Continued use of this operation is necessary to determine its usefulness.

Complete primary structure of prostatropin, a prostate epithelial cell growth factor

Bovine brain prostatropin is a potent and essential mitogen for prostate epithelial cell growth. The major form of prostatropin contains 154 amino acid residues in a single amino terminally blocked chain corresponding to a molecular weight of 17,400. The amino acid sequence of the 150 carboxy-terminal residues of prostatropin was derived by Edman degradation of overlapping peptides primarily generated by cleavage at lysyl and glutamyl residues. Analysis of the amino-terminal tetradecapeptide by fast atom bombardment mass spectrometry identified the blocking group as an acetyl moiety, and tandem mass spectrometry provided the sequence of the first 12 residues. Prostatropin residues 15-154 contain the sequence of bovine brain polypeptides recently described as acidic fibroblast growth factor and class I heparin-binding growth factor. The sequence of the first 25 residues of prostatropin is acetyl-Ala-(Gly, Glu)-Glu-Thr-Thr-Thr-Phe-Thr-Ala-Leu-Thr-Glu-Lys-Phe-Asn-Leu-Pro-Leu-Gly -Asn-Tyr-Lys-Lys-Pro. Reduced and carboxymethylated prostatropin exhibits mitogenic activity, suggesting that disulfide bonds among cysteine residues 30, 61, and 97 are not functionally essential. These results demonstrate by rigorous structural analysis that the brain-derived polypeptide previously described only as a mesenchymal and neuroectodermal cell mitogen is also an epithelial cell growth factor that may be involved in support of prostate hyperplasia and adenocarcinoma.

CT appearance of cervical lipoblastoma

We describe a case of lipoblastoma causing respiratory symptoms in an infant, where CT was useful in establishing the diagnosis and demonstrating the extent of involvement so that complete surgical resection could be planned.

Transplantation of normal bone marrow into a pig with severe von Willebrand's disease

Bone marrow from a normal male pig was transplanted into a related female pig with severe homozygous von Willebrand's disease (vWd). After engraftment the circulating leukocytes were of the male karyotype, and the platelets were strongly positive for von Willebrand factor (vWF) by indirect immunofluorescence. The average level of vWF was 1.96 U/dl and of ristocetin cofactor was 2.8 U/dl. The ear immersion bleeding time before transplantation was consistently more than 15 min and afterwards varied between 5 min and more than 15 min. Transfused vWF corrected the bleeding time at a level of 10 U/dl, which is lower than that required for a von Willebrand pig. We concluded that: the plasmatic compartment is only minimally replenished by the vWF from platelets and megakaryocytes; and the platelet vWF alone only partially corrects the abnormal tests of the hemostatic mechanism in severe vWd.