Autonomic and haemodynamic responses to SK & F 101468 (ropinirole), a DA2 agonist, in anaesthetised cats

The haemodynamic and autonomic nervous system effects of the DA2 agonist, SK & F 101468, have been studied in anaesthetised cats. SK & F 101468 inhibited the tachycardia response to cardiac accelerans nerve stimulation. The inhibition, reversed by L-sulpiride a selective DA2 receptor antagonist, was dose-dependent over the dose range 10-50 micrograms.kg-1 and there was proportionally greater inhibition of the responses to low rather than high frequency stimulation. There was evidence that SK & F 101468-A inhibited sympathetically mediated reflexes, but even at high doses, of up to 500 micrograms.kg-1, there was no inhibition of end-organ responsiveness to noradrenaline, isoprenaline or acetylcholine nor of the bradycardia caused by vagus nerve stimulation. SK & F 101468-A produced falls in blood pressure and heart rate at 50 and 500 micrograms.kg-1, but stroke volume, aortic blood flow and total peripheral resistance, were only slightly affected. These effects of SK & F 101468 in the intact cardiovascular system are consistent with an action on presynaptic receptors at sympathetic nerve endings to reduce transmitter release and thereby selectively reduce responses to sympathetic nerve stimulation.

A case of necrobacillosis

A case of empyema due to Fusobacterium necrophorum infection is described. A history of sore throat followed by metastatic abscesses may alert the clinician to the possibility of this unusual infection.

Identification of a talin binding site in the cytoskeletal protein vinculin

Binding of the cytoskeletal protein vinculin to talin is one of a number of interactions involved in linking F-actin to cell-matrix junctions. To identify the talin binding domain in vinculin, we expressed the NH2-terminal region of the molecule encoded by two closely similar, but distinct vinculin cDNAs, using an in vitro transcription translation system. The 5' Eco RI-Bam HI fragment of a partial 2.89-kb vinculin cDNA encodes a 45-kD polypeptide containing the first 398 amino acids of the molecule. The equivalent restriction enzyme fragment of a second vinculin cDNA (cVin5) lacks nucleotides 746-867, and encodes a 41-kD polypeptide missing amino acids 167-207. The radiolabeled 45-kD vinculin polypeptide bound to microtiter wells coated with talin, but not BSA, and binding was inhibited by unlabeled vinculin. In contrast, the 41-kD vinculin polypeptide was devoid of talin binding activity. The role of residues 167-207 in talin binding was further analyzed by making a series of deletions spanning this region, each deletion of seven amino acids contiguous with the next. Loss of residues 167-173, 174-180, 181-187, 188-194, or 195-201 resulted in a marked reduction in talin binding activity, although loss of residues 202-208 had much less effect. When the 45-kD vinculin polypeptide was expressed in Cos cells, it localized to cell matrix junctions, whereas the 41-kD polypeptide, lacking residues 167-207, was unable to do so. Interestingly, some deletion mutants with reduced ability to bind talin in vitro, were still able to localize to cell matrix junctions.

Innocuous gas collections in pancreatic allografts demonstrated by computed tomography

Over a 4-year period, 6 pancreatic abscesses were found in 37 patients who had combined renal and segmental pancreatic transplants. An additional 4 patients who were nontoxic at the time of their computed tomographic (CT) examinations had innocuous gas collections, either in the pancreatic allograft or the surrounding peripancreatic tissue. The possible etiology of this gas formation is discussed. These collections do not have the same ominous clinical significance as would be expected in abscess formation. Radiological evaluation should include examination of the gastrointestinal tract and voiding cystograms to detect fistula formation. Simultaneous percutaneous aspiration of this area should be performed to rule out an infective process. If this is negative in a nontoxic transplant patient, the radiologist will be in a position to obviate unnecessary surgical intervention.

Metoclopramide-induced parkinsonism

Metoclopramide hydrochloride (Reglan) is a widely prescribed drug for treatment of upper gastrointestinal symptoms. Although the drug is relatively safe, a growing body of literature has noted movement disorders after its administration. We have reported six cases of metoclopramide-induced parkinsonism seen in consultation over a two-year period. Five of these six patients had renal failure. Their parkinsonism improved on discontinuation of metoclopramide therapy. Metoclopramide-induced parkinsonism is not rare, and appropriate dose reduction in patients with renal failure will help reduce the incidence of this morbidity.

Topical corticosteroid compounding: effects on physicochemical stability and skin penetration rate

Compounding compatibility studies of four corticosteroid cream products and four commonly added chemicals are presented. Physical alteration, chemical stability, micropreservative challenge status, and in vitro skin penetration were evaluated at ambient conditions for 2 months. The study was designed to generate useful, previously unavailable information to aid dispensing pharmacists and dermatologists.

Pancreatic transplant rejection: assessment with duplex US

The value of duplex ultrasonography (US) in the assessment of pancreatic transplants was studied in 22 patients over a 1 1/2-year period. Ninety-eight duplex US examinations were performed, and the Doppler arterial resistive indexes (RIs) correlated with clinical events after transplantation. The RI was 0.70 or less in the parenchymal vessels in all instances of normal transplant function and greater than 0.70 in seven of eight clinical episodes of rejection (87.5%). In all studies performed during these eight cases of rejection, the positive predictive value of an RI exceeding 0.70 was 100%. The negative predictive value of an RI of less than 0.70 in excluding rejection was 90%. High RI values were not found in isolated episodes of cyclosporine toxicity, pancreatitis, peripancreatic hemorrhage, or infection. Duplex US may prove to be more accurate in the diagnosis of rejection of pancreatic transplants versus renal transplants because the former cases have fewer causes of increased vascular impedance and diminished perfusion.

Ventricular vulnerability in diabetes and myocardial norepinephrine release

Previously the authors have observed a reduction of the ventricular fibrillation threshold (VFT) in a mild diabetic model. This investigation examines the role of more severe hyperglycemia in altering the ventricular fibrillation threshold and how the sympathetic nervous system modulates the response. Alloxan diabetes was induced in eight male mongrel dogs 3-5 years of age (Group 2), for comparison with matched controls (Group 1). Hemoglobin A1c rose from 2.9 +/- .4-7.8 +/- .3% and body weight was maintained with daily insulin. After 1 year, anesthesia was induced with chloralose and an electrode catheter placed at the right ventricular apex. VFT was 41.7 +/- 1.8 ma in Group 1 and 27.8 +/- 2.1 ma in the diabetics of Group 2 (p less than .001). There was significantly greater decline of VFT in response to epinephrine infusion in Group 2. The threshold in diabetics rose to normal levels after infusion of the beta-blocking agent, esmolol. Subsequently, the response of the cardiac sympathetic system was assessed during ventricular pacing at 200 beats/minute. Serial paired blood samples were taken from catheters in the aorta and coronary sinus for catecholamine assay by HPLC. Both groups had similar coronary blood flow responses by the thermal method, as well as changes in arterial pressure. While no change occurred in Group 1, a progressive rise of norepinephrine (NE) concentration was observed in coronary venous effluent of Group 2 (p less than .01). The basal arterial-coronary sinus difference was-123 +/- 52 pg/ml, which rose during pacing in Group 2 to a peak of -376 +/- 9.3 pg/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding protein, radioreceptor and biological activities of recombinant methionyl insulin-like growth factor-I variants

Reversed-phase chromatography (RPC) was used to resolve two variants of recombinant amino terminal methionyl residue (N-Met) insulin-like growth factor-I (IGF-I) with the same amino acid constitution but different disulphide linkages. Following radioiodination, equilibration with plasma and size exclusion chromatography at neutral pH the major form on RPC (approximate abundance 60%) demonstrated greater than 80% binding to 150 kDa and 40-50 kDa IGF binding proteins. This peptide has the RPC elution characteristics and disulphide assignment (Cys6-Cys48, Cys18-Cys61, Cys47-Cys52) of authentic with mismatched disulphides (Cys6-Cys47, Cys18-Cys61, Cys48-Cys52; N-Met IGF-I peak 1 peptide) demonstrated less than 15% binding under similar conditions. Potency of the peptides was investigated in competitive IGF-I plasma binding protein and L6 myoblast radioreceptor assays. The peak 2 peptide proved equipotent to purified ovine plasma IGF-I in each system but by contrast the peak 1 peptide was 40-fold and 200-fold less potent in the binding protein and radioreceptor assays respectively. Biological potency was examined in a non-competitive assay based on incorporation of [3H]leucine into confluent cultures of L6 myoblasts. In this system the N-Met IGF-I peak 1 peptide proved 15-fold less potent than the peak 2 peptide with correct disulphide linkages. Refolding variants may prove useful in establishing structure/function relationships for IGF-I.

Effect of a partial trisomy in the mouse upon cellular and nuclear RNA

In a previous paper (Rake and Edwards, 1987) it was shown that the majority of the chromatin from trisomic mouse cells has nucleosomes with a smaller repeat length of DNA than the nucleosome repeat length of normal cells. Here it is shown that the RNA content of the total cell and of the nuclei is the same in all tissues studied, in both normal and trisomic cells. However, the amount per unit time or rate of RNA synthesis is depressed in the trisomic liver and brain nuclei. The depression of RNA synthesis could not be specified to the small trisomic section of the chromatin but instead must reflect the overall nuclear activity. These results, along with those of Devlin et al. (1988), indicate that the trisomic condition alters a substantial part of nuclear organization and activity, not just the small trisomic part.

Structure and expression of the glycoprotein gene of Chandipura virus

A cDNA copy of the mRNA for the glycoprotein G of Chandipura virus, a rhabdovirus, has been cloned, sequenced, and expressed in mammalian cells. The deduced amino acid sequence of G shows that the encoded protein is a typical transmembrane glycoprotein of 524 amino acids containing a cleavable amino-terminal signal peptide, two potential N-linked glycosylation sites, a hydrophobic membrane anchor domain near the carboxy terminus, and a cytoplasmic domain at the carboxy terminus. Somewhat unusual is the appearance of two charged amino acid residues, aspartate and arginine, within the putative membrane anchor sequence. Expression of the G gene in COS cells resulted in production of a glycosylated protein of mol wt 71,000 which was recognized by anti-Chandipura antibodies. Like the viral G protein, the expressed G contained covalently linked palmitic acid. However, unlike its vesicular stomatitis virus (Indiana serotype) counterpart, the Chandipura G protein has no potential palmitate-accepting cysteine residue within its cytoplasmic domain. Thus, the covalent attachment of fatty acid to this molecule may occur at one or both of the cysteines within the membrane anchor domain. The G protein was intracellularly transported to the cell surface and could induce cell fusion at low pH, showing that the expressed G protein was biologically active.

Primary sequence and domain structure of chicken vinculin

We have determined the complete sequence of chick vinculin from two overlapping cDNA clones. The vinculin mRNA consists of 262 bp of 5' untranslated sequence, an open reading frame of 3195 bp (excluding the initiation codon) and a long 3' untranslated sequence (greater than 2 kb). Chick vinculin contains 1066 amino acid residues, and has a deduced molecular mass of 116,933 Da. Analysis of the domain structure of vinculin shows that the molecule can be cleaved by V8 proteinase into a 90 kDa globular head and a 32 kDa tail region, the latter of which could further be cleaved into a 27 kDa polypeptide. The 90 kDa globular head contains the N-terminus of vinculin, three 112-residue repeats (residues 259-589), and extends to approximately residue 850. Gel overlay experiments show that it also contains a binding site for the cytoskeletal protein talin. The talin-binding domain was further localized to the N-terminal 398 amino acid residues of the protein by expression in vitro of this region from a vinculin cDNA cloned into the Bluescript SK+ vector. The head and tail domains are apparently separated by a proline-rich region that contains V8-proteinase-cleavage sites and a candidate tyrosine (822)-phosphorylation site. Secondary-structure prediction suggests that the head and tail domains contain alpha-helical regions separated by short stretches of turn/coil. Comparison of the chick with a partial human sequence reveals that vinculin is a highly conserved protein. In chickens Southern-blot analysis is consistent with a single vinculin gene, and it is therefore likely that vinculin, and its higher-molecular-mass isoform termed metavinculin, arise through alternative splicing.

The clinical syndrome of 5-fluorouracil cardiotoxicity

5-fluorouracil (FUra) is one of the most frequently used drugs in cancer treatment, particularly in combination with other agents. Its activity when administered as an infusion rather than a bolus has led to a renewed and increased use. A cardiotoxicity that mimics ischemia has been associated with the administration of FUra in cancer patients. This cardiotoxicity may manifest itself as: (a) dysrythmias with and without cardiorespiratory symptoms (b) ECG changes with and without cardiorespiratory symptoms (c) cardiorespiratory symptoms with and without ECG changes (d) acute myocardial infarct; symptoms and ECG changes (e) ventricular dysfunction (f) cardiogenic shock and (g) sudden death. Several case studies which illustrate the cardiotoxic sequelae that may be associated with the use of this drug are discussed. The incidence, contributing factors, risk factors and mechanisms underlying this phenomenon are undetermined. No appropriate recommendations for monitoring patients or for predicting those patients that will develop such toxicity while receiving FUra can be made at present. Prospective studies to determine the true incidence, spectrum and mechanisms causing this syndrome are ongoing and required for its understanding and prevention.

Altered myocardial states. The stunned and hibernating myocardium

There are several potential outcomes of myocardial ischemia. When ischemia is severe and prolonged, myocyte cell death occurs and there is no recovery of contractile function of these cells. When myocardial ischemia is less severe but still prolonged, myocytes may remain viable but exhibit depressed contractile function, which may be a protective mechanism whereby these cells attempt to reduce their oxygen demand in the setting of reduced oxygen supply. The resultant chronic left ventricular dysfunction has been termed "hibernating myocardium." Finally, myocardial ischemia may be reversed with coronary artery reperfusion resulting in salvage of the myocytes. However, the viable myocardium may demonstrate relatively prolonged but transient postischemic contractile dysfunction, the situation termed "stunned myocardium." The concepts of stunned myocardium are reviewed as they apply to both coronary reperfusion during evolving acute myocardial infarction, as well as brief periods of ischemia that may occur during angina pectoris, or coronary vasospasm, or both. The concept of hibernating myocardium is reviewed as it applies to left ventricular function prior to and after coronary artery bypass surgery.

Coagulation cascade, fibrinolytic system, antithrombin III, protein C and protein S in patients maintained on continuous ambulatory peritoneal dialysis

We studied the coagulation cascade, fibrinolytic system and naturally occurring anticoagulants in a group of 14 patients with end-stage renal disease maintained on continuous ambulatory peritoneal dialysis (CAPD). The results were compared with those obtained in a group of ten normal volunteers. Plasma procoagulant activities of factors XII, XI, IX, VIII, VII, X and II were significantly greater in the CAPD group as compared to the normal control group. Likewise plasma concentrations of total and free protein S were increased in the CAPD group. Although the mean value for plasma factor V activity in the CAPD group was higher than that found in the control group the difference did not attain statistical significance. In addition plasma fibrinogen concentration and factor VIII-related antigen level were significantly increased in CAPD patients. No significant difference was found between the CAPD patients and the control group with respect to plasma levels of protein C, antithrombin III, plasminogen or alpha 2-antiplasmin. In summary, the results demonstrate a tendency for increased levels of various coagulation factors and protein S in CAPD patients with no significant alterations in the levels of various fibrinolytic and endogenous anticoagulant agents, i.e. antithrombin III and protein C. The clinical significance and the mechanism responsible for the observed changes require further investigation.

Quantification of myocardial infarction during coronary occlusion and myocardial salvage after reperfusion using cardiac imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile

Myocardial imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile was investigated as a means to assess myocardial infarct size during coronary occlusion and to quantify the extent of salvaged myocardium after coronary occlusion followed by reperfusion. Open chest dogs underwent either a permanent coronary artery occlusion (Group 1, n = 16) or a 2 h occlusion followed by reperfusion (Group 2, n = 15). Animals in both groups were killed 48 h after occlusion. During coronary occlusion, 23 of the 25 dogs that survived the coronary occlusions had abnormal myocardial scintigrams. The scintigraphic perfusion defect size correlated well with the pathologic infarct size (r = 0.85 and 0.95 by planar and tomographic imaging, respectively). The planar scintigraphic defect size, but not the tomographic defect size, overestimated the pathologic size. The planar scintigraphic defect size observed during coronary occlusion was markedly reduced 48 h after reperfusion (24.8 +/- 12.8% to 10.6 +/- 9.7% of the left ventricle, p less than 0.003). The uptake of technetium-99m hexakis 2-methoxyisobutyl isonitrile in the ischemic myocardium increased significantly 48 h after reperfusion (p less than 0.003) and correlated with the increase in regional myocardial blood flow, as assessed by radioactive microspheres (r = 0.83, p less than 0.01). Thus, myocardial imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile allows reliable demonstration of the presence of acute infarction, estimation of infarct size and quantification of the extent of salvaged myocardium after coronary reperfusion.

Neutropenic colitis: evaluation with computed tomography

The computed tomography findings of 10 patients with neutropenic colitis are described and illustrated. Seven of these patients had leukemia, one had lymphocytic lymphoma, and two had systemic lupus erythematosus. All patients had colon wall thickening which was either isodense with the normal bowel tissue or showed areas of intramural low density. Air in the thickened bowel wall was seen in six patients. These computed tomography findings in neutropenic patients with fever, abdominal pain, and diarrhea should suggest the diagnosis in most instances, resulting in prompt treatment of this usually life-threatening entity.

Lamellar macular hole associated with idiopathic juxtafoveolar telangiectasia

A case of juxtafoveolar telangiectasia complicated by lamellar, retinal hole is reported and the pathogenesis discussed. This association is not commonly recognised.

Pancreatic transplantation: scintigraphy, US, and CT

Twenty-one patients with insulin-dependent diabetes mellitus received simultaneous renal and segmental pancreatic transplants. A retrospective analysis of 112 real-time ultrasound (US) images, 108 technetium-99m glucoheptonate scinti-scans, 55 computed tomography (CT) scans, and 11 cystograms was performed. Complications that were observed included pancreatic transplant rejection, pancreatitis, arteriovenous occlusions, hemorrhage, abscesses, and extravasation at the pancreaticocystostomy site. Scintigraphy is a sensitive indicator of normal transplant function but is non-specific when findings are abnormal. Real-time US aids in the differentiation of acute rejection from pancreatitis and arteriovenous occlusion. CT is helpful for evaluation of postoperative complications. Imaging may play an important role in the noninvasive management of pancreatic transplants.

Preoperative evaluation with radionuclide brain scanning and computerized axial tomography of the brain in patients with breast cancer

To determine the roles of radionuclide brain scanning and computerized tomography of brain in the pretreatment evaluation of patients with primary and locoregional recurrence of breast cancer, we reviewed the clinical and radiologic findings in 226 patients with breast cancer who underwent one of these scans either preoperatively or within 6 weeks of operation and in 34 patients presenting with locoregional recurrence. Four of 131 radionuclide brain scans in primary breast cancer suggested calvarial metastasis, and the findings were confirmed with bone scans and skull radiographs. One of 95 computerized tomographic scans of the brain showed brain metastasis, and this patient had profound neurologic deficits. With respect to locoregional recurrence, the results of 2 of 23 radionuclide scans and 1 of 11 computerized tomographic scans were positive. All three patients had clinical evidence for brain metastasis. We conclude that in the absence of signs and symptoms, routine evaluation for brain metastasis is not justified in primary and locoregional recurrence of breast cancer.

Increased levels of protein C activity, protein C concentration, total and free protein S in nephrotic syndrome

Plasma protein C (PC) antigen concentration has been shown to be normal or increased in patients with proteinuria. However, the available data concerning PC anticoagulant activity in nephrotic syndrome (NS) are limited. We measured plasma PC antigen concentration. PC anticoagulant activity, total and free protein (PS) concentrations, and antithrombin III (AT-III) antigen concentration in 21 adult patients with NS. The results were compared with those obtained in a control group of normal volunteers. PC antigen concentration and its anticoagulant activity were significantly increased in the NS group when compared with the normal control group. Likewise, plasma total and free PS values were significantly higher in the NS patients than the corresponding values found in the control group. In contrast, plasma AT-III antigen concentration was significantly reduced in patients with NS. A negative correlation was found between plasma PC and AT-III levels. These observations suggest that increased plasma PC concentration and anticoagulant activity in NS may afford some protection against the thrombotic diathesis associated with antithrombin deficiency and other coagulation abnormalities in this otherwise hypercoagulable state.

Factors that determine the occurrence of reperfusion arrhythmias

The determinants of reperfusion arrhythmias were investigated in 63 open-chest dogs undergoing a 25-minute coronary artery occlusion followed by reperfusion. Heart rate correlated positively with the occurrence of reperfusion ventricular tachycardia (VT) and ventricular fibrillation (VF). Collateral flow during ischemia (radioactive microspheres) exhibited a strong negative correlation with the incidence of both VT and VF upon reperfusion. Importantly, a sensitive coupling was present, whereby small differences in flow were associated with large differences in rhythm disorders. The rise in intramyocardial CO2 tension (another index of severity of ischemia) was greater in dogs exhibiting reperfusion VT (p less than 0.001) and VF (p less than 0.08); however, this variable was significantly correlated with collateral flow (r = -0.57, p less than 0.01). The size of the occluded coronary bed, determined by postmortem perfusion, was not consistently related to VT; within a given range of occluded bed sizes, the incidence of VT was inversely related to collateral flow. Thus, reperfusion-induced VT is relatively independent of the size of the occluded bed, and is determined primarily by the degree of myocardial hypoperfusion. In contrast, VF did not develop with occluded beds less than 25% of the left ventricular mass; above this critical occluded bed size, its incidence was inversely related to collateral perfusion. Reperfusion VF is therefore determined by the association of a large occluded bed with a poor collateral flow. This study identifies and systematically analyzes three major determinants of reperfusion arrhythmias: (1) the severity of antecedent ischemia, estimated either from the degree of flow reduction or the rise in intramural CO2 tension; (2) the amount of ischemic/reperfused myocardium; and (3) the heart rate. In addition to conceptual interest and clinical implications, the findings have important implications for the design of future studies aimed at evaluating antiarrhythmic interventions in experimental models.

Protein C abnormalities in spinal cord injured patients with end-stage renal disease

Patients with chronic spinal cord injury (SCI) and end-stage renal disease (ESRD) exhibit antithrombin III deficiency and several other coagulation abnormalities. In view of increasing recognition of protein C (PC) as an important, naturally occurring anticoagulant and fibrinolytic factor, we studied plasma PC in this population. PC antigen concentration and its anticoagulant activity were measured in nine SCI men with ESRD maintained on hemodialysis and in a control group of ten normal able-bodied men. The results showed a significant increase in PC anticoagulant activity in the SCI group. Consequently, the ratio of the PC activity to its concentration, which is a measure of the functional integrity of PC molecule, was markedly depressed. These findings are indicative of the presence of inactive or abnormal PC in SCI-ESRD patients and may suggest its in vivo activation. The combination of impaired PC activity shown in this study, with previously demonstrated antithrombin III deficiency and other coagulation abnormalities, is suggestive of a hypercoagulable state.

Corticosteroid-responsive pure red cell aplasia in chronic lymphatic leukemia

Acquired pure red cell aplasia characterized by selective failure of erythropoiesis was seen in a 37-yr-old female patient with a diagnosis of chronic lymphatic leukemia (CLL). Though different immunosuppressive therapies have been tried in the past with variable response, there has been no case report of such favorable response to corticosteroids alone. We report this rare and unusual case of PRCA associated with CLL who responded to steroid therapy.

The effect of alcohol on nocturnal gastroesophageal reflux

The effect of 120 mL (4 oz) of scotch whiskey (40% alcohol) on nocturnal gastroesophageal reflux was studied by ambulatory esophageal pH monitoring. Seventeen healthy volunteers were studied on two occasions, using a computerized radiotelemetric esophageal pH monitoring system. The subjects were given the alcohol during the second session, three hours after the evening meal, and went to bed at their usual time. Seven of the 17 subjects had prolonged supine reflux episodes on the night of alcohol ingestion. These lasted an average of 47.1 minutes (23.2 to 91.8 minutes) and occurred on an average of 3 1/2 hours after ingestion of whiskey and 1.4 hours after lying down. None of the subjects had these episodes on the control night. There was also a significant acidic shift in the cumulative percentage of data points below a pH of 3 and a pH of 4 in the supine position on the night of alcohol ingestion compared with the control night. This study has shown that there was a significant exposure of the distal esophagus to acid and that the normal acid clearance of the esophagus in the supine position was impaired after only moderate amounts of alcohol.

5-Fluorouracil cardiotoxicity: left ventricular dysfunction and effect of coronary vasodilators

Seven patients developed clinical features simulating myocardial ischemia less than 72 hours after 12 of 13 separate intravenous 5-fluorouracil administrations; 9 episodes were associated with chest pain, 3 with hypotension, 3 with ventricular tachycardia and 1 with cardiogenic shock. Left ventricular dysfunction was demonstrated by echocardiography in 5 separate episodes, 2 with interval improvement upon repeat echocardiograms. Pretreatment with nitrates and/or calcium channel blockers failed to prevent recurrence of cardiotoxicity during 5 of 6 repeat 5-fluorouracil administrations. Therapy with 5-fluorouracil is associated with cardiotoxicity simulating myocardial ischemia with left ventricular dysfunction. Pretreatment with coronary vasodilators may not prevent this phenomenon.

Isolation and characterization of a vinculin cDNA from chick-embryo fibroblasts

A chick-embryo fibroblast lambda gt11 cDNA library was screened with affinity-purified antibodies to chick gizzard vinculin. One recombinant was purified to homogeneity and the fusion protein expressed in Escherichia coli strain C600. The fusion protein was unstable, but polypeptides that reacted with vinculin antibodies, but not non-immune immunoglobulin, were detected by Western blotting. The recombinant contained a single EcoRI fragment of 2891 bp with a single open reading frame. The deduced protein sequence could be aligned with that of six CNBr-cleavage peptides and two tryptic peptides derived from chicken gizzard vinculin. AUG-247 has tentatively been identified as the initiation codon, as it is contained within the consensus sequence for initiation sites of higher eukaryotes. The cDNA lacks 3' sequence and encodes 74% of the vinculin sequence, presuming the molecular mass of vinculin to be 130,000 Da. Analysis of the deduced sequence showed no homologies with other protein sequences, but it does display a triple internal repeat of 112 amino acid residues covering residues 259-589. The sequences surrounding the seven tyrosine residues in the available sequence were aligned with the tyrosine autophosphorylation consensus sequence found in protein tyrosine kinases. Tyr-822 showed a good match to this consensus, and may represent one of the two major sites of tyrosine phosphorylation by pp60v-sre. Northern blots showed that the 2.89 kb vinculin cDNA hybridized to one size of mRNA (approx. 7 kb) in chick-embryo fibroblasts, chick smooth muscle and chick skeletal muscle. Southern blots revealed multiple hybridizing bands in genomic DNA.

Morphological and immunocytochemical identification of indoleamine-accumulating neurons in the cat retina

The type and distribution of indoleamine-accumulating neurons were studied in the cat retina. The neurons were characterized by their capacity to take up an exogenous indoleamine, 5,6-dihydroxytryptamine, which could then be visualized using formaldehyde-induced fluorescence. Under direct microscopic control, intracellular injection of Lucifer yellow into the labeled cells revealed that the indoleamine-accumulating neurons comprise 2 distinct morphological types of amacrine cell and 1 class of ganglion cell. The dendritic morphology and retinal distribution of these cells were studied in detail. The proportion of retinal cells that accumulate 5-HT was measured using 5-HT (5-hydroxytryptamine) preloading in vitro and immunocytochemistry with an anti-5-HT antibody. Only 1 type of amacrine cell showed uptake of 5-HT at a concentration of 10(-7) M. Cells containing endogenous 5-HT were not detected by immunocytochemistry.

Differential pulse polarographic determination of sulfites in foods: collaborative study

A differential pulse polarographic (DPP) method for the determination of "free" and "total" sulfite in foods was collaboratively studied by 8 laboratories. The collaborators analyzed blind duplicate samples of shrimp, orange juice, peas, dried apricots, and dehydrated potatoes. Collaborators also analyzed the same samples spiked with sulfites at 2 levels, which ranged from 10 to 1100 micrograms added SO2/g. The variability of free SO2 results was excessive for quantitative analysis, but the method can be used for qualitative detection of free SO2. The method for total SO2 determination was suitable for as low as approximately 10 micrograms/g. Recoveries are comparable to those for the official Monier-Williams method at high levels and are superior at low levels. The method has been adopted official first action for determination of total SO2 in the foods studied.

Evaluation of bone scan as a screening work-up in primary and local-regional recurrence of breast cancer

To evaluate the use of radionuclide bone scan in staging patients with primary and local-regional recurrence of breast cancer, we reviewed the results in 265 patients with primary breast cancer who had the scan either preoperatively or within 6 weeks of surgery, and in 39 patients presenting with their first local-regional recurrence. All patients were clinically staged according to the revised 1983 criteria of the American Joint Committee for Cancer Staging and End-Results Reporting. None of the 92 with stage I and four of 95 patients with stage II had a positive scan. Eleven of 41 with stage IIIA and 13 of 37 with stage IIIB had a positive bone scan. In patients with their first local-regional recurrence, 12 of 39 had a positive scan. Follow-up scans were available in 61 patients with clinical stage I and II breast cancer who had adjuvant chemotherapy for pathological involvement of axillary node. There were six conversions observed in 61 scans obtained during the first year. Seven converted in follow-up scans in 47 patients in the second year. We conclude that although bone scans have a low positive yield in stage I and II breast cancer, their use in the preoperative setting and in the follow-up of patients with axillary node involvement detects early converters. Bone scans are justified in stage IIIA and IIIB breast cancer and in patients being evaluated for local-regional recurrence.

Analysis of reported randomized trials of streptokinase therapy for acute myocardial infarction in the 1980s

Trials of intracoronary (IC) and intravenous (IV) streptokinase (SK) therapy for myocardial infarction have shown variable effects on mortality and left ventricular (LV) function. A pooled analysis of 10 randomized trials involving a total of 14,355 patients was performed to look for overall trends in the change in mortality within 6 weeks (group A) and after 6 weeks (group B) of follow-up, and the change in LV function. All 10 trials, 7 with IC and 3 with IV SK, were randomized after 1980. There was a significant reduction in mortality risk in patients in group A treated with IV SK (pooled odds ratio = 0.81, 95% confidence interval = 0.73 to 0.90, p less than 0.001). In contrast, no significant differences in mortality were detected in patients in group B treated with IV SK or in patients in either group treated with IC SK. Two IV SK trials that prospectively stratified patient population according to duration of symptoms showed a greater reduction in mortality with administration of SK therapy within 3 hours of onset of symptoms. Analysis of LV function was performed before, within 96 hours after and 1 to 4 weeks after SK therapy. Only 2 of 7 IC SK trials showed significantly greater improvement in global LV ejection fraction in SK group compared with a control group, both showing improvement in LV function between early and late after treatment. Thus, IV SK therapy significantly reduces short-term risk of death after acute myocardial infarction; 2 trials show a greater reduction in mortality risk with earlier institution of IV SK therapy.

Isolation and characterization of a cDNA encoding a chick alpha-actinin

We have isolated and sequenced a 2.1-kilobase cDNA encoding 86% of the sequence of alpha-actinin. The cDNA clone was isolated from a chick embryo fibroblast cDNA library constructed in the expression vector lambda gt11. Identification of this sequence as alpha-actinin was confirmed by immunological methods and by comparing the deduced protein sequence with the sequence of several CNBr fragments obtained from adult chicken smooth muscle (gizzard) alpha-actinin. The deduced protein sequence shows two distinct domains, one of which consists of four repeats of approximately 120 amino acids. This region corresponds to a previously identified 50-kDa tryptic peptide involved in formation of the alpha-actinin dimer. The last 19 residues of C-terminal sequence display an homology with the so-called E-F hand of Ca2+-binding proteins. Hybridization analysis reveals only one size of mRNA (approximately 3.5 kilobases) in fibroblasts, but multiple bands in genomic cDNA.

Anthralin stain removal

Results of an anthralin stain removal study on white 65% polyester/35% cotton, white 100% polyester, white 100% cotton, a white shower curtain, white tile with crevice, and white ceramic shower tile are reported. An optimum stain removal technic was developed by using a 10-minute soak in full-strength chlorine bleach (Good Measure or Clorox) followed by a water rinse and air drying. This technic completely removed all stains of 24-hour duration from the test fabrics. The stain removal test on shower curtains, floor tiles, and ceramic shower tiles was also discussed.

Increase in the number of type II insulin-like growth factor receptors during propylthiouracil-induced hyperplasia in the rat thyroid

We have observed that membranes isolated from rat thyroids contain receptors for the insulin-like growth factors (IGF). As IGFs are known to be important mediators of tissue growth, we conducted this study to determine whether modulation of thyroid IGF receptors might be involved in TSH-stimulated hyperplasia. A substantial increase in both the weight of the thyroid and its DNA content was observed within 2 days of exposing adult male rats to 0.1% propylthiouracil (PTU) in their drinking water. Serum T4 reached unmeasurable levels and serum TSH rose 3-fold over control by the tenth day of treatment. [125I]Iodo-human(h)IGF-II binding to membranes isolated from hyperplastic glands was significantly higher than control beginning at 2 days. A maximum was reached after 5 days (13.3 +/- 0.8%/25 micrograms protein vs. a control level of 6.7 +/- 0.7%, mean +/- SEM). The increase had disappeared by 15 days of PTU exposure, paralleling the drastic fall in the growth rate of the glands. This increase in binding was specific for the thyroid, as it was not seen in other organs. In both treated and control animals, the receptor involved was shown to be type II by preferential binding to IGF-II, lack of interaction with insulin, and molecular sizing. The observed increase in binding could be accounted for by an increase in receptor site number, the affinity remaining essentially the same. We conclude that the TSH-stimulated hyperplasia of the rat thyroid, induced by PTU, is associated with an increase in the binding sites of the type II IGF receptor. This observation raises the possibility that modulation of this receptor may play a role in the mediation of the mitogenic effect of TSH on the thyroid gland.

The use of Rous sarcoma virus transformation mutants with differing tyrosine kinase activities to study the relationships between vinculin phosphorylation, pp60v-src location and adhesion plaque integrity

Tyrosine-specific phosphorylation of cellular proteins has been implicated in the neoplastic transformation of cells by Rous sarcoma virus (RSV). One of the putative substrates for the src gene product (pp60v-src) of RSV is the cytoskeletal protein vinculin, giving rise to the hypothesis that tyrosine-specific phosphorylation of vinculin disrupts adhesion plaque integrity, leading to the characteristic rounded morphology of RSV-transformed cells. We have investigated this hypothesis by analysing the properties of fibroblasts transformed by conditional and non-conditional mutants of RSV which confer different morphologies on infected cells, with respect to formation of microfilament bundles, formation of vinculin-containing adhesion plaques, the deposition of a fibronectin-containing extracellular matrix, the localization of pp60v-src and the tyrosine-specific phosphorylation of vinculin. Cells transformed by the temperature-sensitive (ts) RSV mutant LA32 cultured at 41 degrees C were morphologically normal, and contained prominent microfilament bundles and well-developed adhesion plaques. However, these cells had a fully active pp60v-src kinase, had pp60v-src concentrated in their adhesion plaques and contained vinculin which was heavily phosphorylated on tyrosine residues. Cells transformed by a recovered avian sarcoma virus, rASV 2234.3 exhibited a markedly fusiform morphology with pp60v-src concentrated in well-developed adhesion plaques and an elevation of the phosphotyrosine content of vinculin. Cells transformed by LA32 at restrictive temperature comprise morphologically normal cells, indistinguishable from untransformed CEF, yet which contain tyrosine-phosphorylated vinculin and suggest that neither tyrosine-specific phosphorylation of vinculin nor pp60v-src concentration in adhesion plaques is sufficient for the rounded morphology of RSV-transformed cells.

Comparison of the relative importance of tyrosine-specific vinculin phosphorylation and the loss of surface-associated fibronectin in the morphology of cells transformed by Rous sarcoma virus

We have investigated the relative importance of tyrosine-specific phosphorylation of vinculin and the loss of surface-associated fibronectin in the maintenance of the rounded morphology characteristic of chick embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV). To address this question we have examined the interaction of CEF and RSV-CEF in vitro with exogenously added fibronectin in both 3-day culture experiments and short-term, 3-h spreading experiments. We report that the addition of human plasma fibronectin to cultures of RSV-CEF results in the restoration of a near-normal morphology, as has been described previously, with the added fibronectin incorporated into an extracellular matrix. However, the phosphotyrosine content of vinculin in these cells was unchanged from that of control, untreated RSV-CEF despite the change in morphology. In short-term spreading experiments RSV-CEF were unable to adopt a fully spread morphology on fibronectin substrates, with defects in the formation of adhesion plaques and microfilament bundles compared with untransformed CEF. pp60v-src was present in the newly formed adhesion plaques of RSV-CEF spreading on fibronectin substrates. The relevance of these results to the maintenance of the transformed phenotype is discussed.

Hydrolysis of nicotinyl 6-aminonicotinate

The degradation kinetics of nicotinyl 6-aminonicotinate in aqueous buffer solutions were studied over the pH range from 4.0 to 10.0. In all cases, pseudo-first-order kinetics were observed at constant hydronium ion concentration. The pH-rate profile indicated that the hydrolysis of nicotinyl 6-aminonicotinate may be described by at least two catalytic terms. In alkaline solution the hydrolysis is catalyzed primarily by hydroxyl ions. In acidic solution the hydrolysis may be attributed to either the water-catalyzed reaction of the protonated species or the hydronium ion catalyzed reaction of the free base. The resulting catalytic profile afforded a sharp pH minimum of approximately 5.90 at 65 degrees C. An activation energy of 16 Kcal/mol was obtained in a phosphate buffer solution at a pH of approximately 5.90 +/- 0.2. The first- and second-order reaction constants for water and hydroxyl ion catalysis were determined, and the temperature dependency of the reaction was studied. The buffer effect and solvent effect on the hydronium and hydroxyl ion catalysis was also investigated.

Can a sponge fractionate isotopes?

The study has unequivocally demonstrated that siliceous sponges Spirastrella cuspidifera and Prostylyssa foetida from the same microecological niche exhibit a high degree of species specificity, while accumulating a host of heavy metal ions (Ni, Cr, Cd, Sn, Ti, Mo, Zr). S. cuspidifera accumulated, in addition, 60Co and 63Ni, showing discrimination against other radionuclides, 137Cs and 131I, present in the ambient waters receiving controlled low level waste discharges from a B.W.R. nuclear power station. P. foetida, on the other hand, accumulated only 131I and showed discrimination against other radionuclides including 60Co, although the stable iodine concentrations in both the sponges were the same. The specific activity of 60Co (in becquerels per gram of 59Co) in S. cuspidifera and 131I (in becquerels per gram of 127I) in P. foetida were at least two orders of magnitude greater than in the ambient sea water. That of 63Ni (in becquerels per gram of 62Ni) in S. cuspidifera, on the other hand, was lower by two orders of magnitude than in either abiotic matrices from the same environment. Thus, not only did both the species show bioaccumulation of a specific element, but also preferential uptake of isotopes of the same element, though they were equally available for intake. Such differential uptake of isotopes can possibly be explained in terms of two quite different mechanisms operating, each applicable in a particular case. One is that the xenobiotic isotope enters the environment in a physicochemical form or as a complex different from that of its natural counterpart. If equilibration with the latter is slow, so that the organism acquires the xenobiotic in an unfamiliar chemical context, it may treat it as a chemically distinct entity so that its concentration factor differs from that of stable isotope, thus changing the specific activity. Alternatively, if the xenobiotic is present in the same chemical form as the stable isotope, the only way in which specific activities can be modified is by fractionation on the basis of mass of isotope. In view of the remarkable concentration factors observed for stable and radioactive isotopes of the same element and the specific activities reached, it is desirable that species of sponges, especially from the coastal and estuarine environments, be monitored to detect levels of pollution due to anthropogenic substances.

Smoking and malignant disease: a general practice study

This study, involving a practice population of 7,200 patients, compared the smoking habits of patients suffering from malignant disease (excluding skin cancer) with the smoking habits of controls matched for age and sex. Patients with malignancies were found to smoke more heavily than their controls; this difference was particularly marked between the younger patients and their controls. Data on the most prevalent malignancies (carcinomata of the breast, cervix, rectum, colon and bladder) revealed that this tendency to heavier smoking was more marked in patients with neoplasia of cervix or bladder than in patients with breast or colorectal neoplasms. The age of these patients at diagnosis was reviewed in relation to smoking habits. Although the numbers were small, it appeared that patients who smoke present at an earlier age than non-smokers, except in cases of neoplasia of the cervix.These results seem to justify further general practice studies into the links between smoking and malignant disease.

Binding and uptake of [125I]iodoprolactin by epithelial cells of the rat choroid plexus: an in vivo autoradiographic analysis

Light and electron microscopic (EM) autoradiography were used to determine the subcellular fate of [125I] iodo-PRL that specifically binds to epithelial cells of the rat choroid plexus. Experimental animals (total binding) received an external jugular vein injection of ovine [125I]iodo-PRL, whereas control animals (nonspecific binding) received an identical dose of [125I]iodo-PRL plus a 500-fold excess of unlabeled PRL. Experimental and control animals were killed by vascular perfusion 3, 20, 40, 60, and 240 min after hormone injection. Choroid plexuses were removed, processed to Epon, and prepared for light and EM autoradiography. Quantification of silver grains at the light microscopic level revealed an intense autoradiographic reaction over the epithelial cells of experimental animals 3, 20, 40, and 60 min after hormone injection. The co-injection of unlabeled PRL resulted in a statistically significant reduction in the autoradiographic reaction throughout the initial 60 min of the test period, reflecting specific binding of PRL during this interval. Analysis of EM autoradiographs revealed that the initial binding of [125I]iodo-PRL occurred primarily at the basal and lateral plasmalemma of the epithelial cells. With time there was a dramatic reduction in the amount of radiolabel localized to the cell membrane and a concomitant increase in silver grains localized over the interior of the cells. Internalized [125I]iodo-PRL exhibited a preferential localization to small cytoplasmic vesicles, short tubules, multivesicular bodies, and dense bodies. Combined acid phosphatase cytochemistry and EM autoradiography revealed that only 11.2% of the internalized silver grains were localized over acid phosphatase-positive structures 40 min after injection. The results indicate that subsequent to the initial binding of [125I]iodo-PRL to the cell membrane, internalization and translocation occurs primarily to nonlysosomal cytoplasmic organelles. The study also demonstrates at least a partial or ultimate entrance of internalized PRL to the lysosomal system.