Severe factor VII deficiency caused by mutations abolishing the cleavage site for activation and altering binding to tissue factor

Factor VII (F.VII) is a vitamin-K-dependent serine protease required in the early stages of blood coagulation. We describe here a patient with severe F.VII deficiency, with a normal plasma F.VII antigen level (452 ng/mL) and F.VII activity less than 1%, who is homozygous for two defects: a G-->A transition at nucleotide 6055 in exon 4, which results in an Arg-->Gln change at amino acid 79 (R79Q); and a G-->A transition at nucleotide 8961 in exon 6, which results in an Arg-->Gln substitution at amino acid 152 (R152Q). The R79Q mutation occurs in the first epidermal growth factor (EGF)-like domain, which has previously been implicated in binding to tissue factor. The R152Q mutation occurs at a site (Arg 152-Ile 153) that is normally cleaved to generate activated F.VII (F.VIIa). Analysis of purified F.VII from patient plasma shows that the material cannot be activated by F.Xa and cofactors. In addition, in an in vitro binding assay using relipidated recombinant tissue factor, patient plasma showed markedly reduced binding to tissue factor at all concentrations tested. In an effort to separate the contributions of the two mutations, three recombinant variants, wild-type, R79Q, and R152Q, were prepared and analyzed. The R152Q variant had markedly reduced activity in a clotting assay, whereas R79Q showed a milder, concentration-dependent reduction. The R152Q variant exhibited nearly normal binding in the tissue factor binding assay, whereas the R79Q variant had markedly reduced binding. The time course of activation of the R79Q variant was slowed compared with wild-type. Our results suggest that the first EGF-like domain is required for binding to tissue factor and that the F.VII zymogen lacks activity and requires activation for expression of biologic activity.

Bone marrow micrometastases in chemotherapy-responsive advanced breast cancer: effect of ex vivo purging with 4-hydroperoxycyclophosphamide

Tumor contamination of hematopoietic stem cell grafts may influence the outcome of breast cancer patients treated with high-dose chemotherapy. The goals of this study were: (a) to evaluate the prevalence of tumor contamination of bone marrow (BM) harvests in patients responding to systemic chemotherapy; (b) to evaluate reduction of BM tumor contamination by ex vivo purging with 4-hydroperoxycyclophosphamide (4HC); and (c) to compare the tumor contamination of peripheral blood progenitor cell collections and BM in advanced-stage breast cancer patients designated for peripheral blood progenitor cell infusion. We evaluated pre- and post-4HC purge BM specimens from 20 patients for tumor contamination using immunocytochemistry and for in vitro growth potential of tumor cells using a tumor cell clonogenic assay. Pre-4HC purge BM specimens from 15 of 20 (75%) patients were immunocytochemistry and tumor cell clonogenic assay negative. The remaining 5 BM specimens were immunocytochemistry positive, but only 3 of 5 specimens were tumor cell clonogenic assay positive. In vitro tumor colony growth was not observed in any post-4HC purge BM specimens. We also evaluated nine patients with bone or BM metastases from the start of induction chemotherapy. We found less tumor involvement of peripheral blood progenitor cell collections than of simultaneously obtained bone marrow aspirates. We conclude that bone marrow micrometastases occur with low frequency in women with chemotherapy-sensitive breast cancer and that ex vivo purging with 4HC may render tumor cells nonviable.

Bicoronary-pulmonary fistulae with coexistent mitral valve prolapse: a case report and literature review of coronary-pulmonary fistula

Bicoronary-pulmonary artery fistulae are rare congenital coronary artery fistulae. We report the case of a 57-year-old man who presented with biventricular failure and angina pectoris. At angiography the coronary arteries were normal, but bicoronary-pulmonary fistulae were noted; severe mitral regurgitation secondary to mitral valve prolapse was also present. At right heart catheterization the calculated left to right shunt was 2.1. Fistula ligation and repair of both mitral and tricuspid valves was undertaken. The literature regarding coronary-pulmonary fistula is also reviewed.

A comparative study of the efficacy and toxicity of etodolac and naproxen in the treatment of osteoarthritis

In a two-period, double-blind, crossover study, patients with osteoarthritis of the knee and/or hip received etodolac 300 mg twice daily for 4 weeks and naproxen 500 mg twice daily for 4 weeks in random order. The assessment of efficacy showed that naproxen and etodolac were equally effective in the management of pain and stiffness in osteoarthritis. However, a significantly higher proportion of patients preferred naproxen to etodolac for the relief of pain intensity. The incidence of adverse events caused by either drug was the same.

A model for the evolution of networks of genes

An organism persists through the activity of structural genes, which is co-ordinated by clusters of coupled regulatory genes. During evolution, changes of coupling within a cluster can increase the reliability with which its structural genes perform a task. To study the evolution of coupling, we have simulated and analyzed a stochastic model for a simple problem. The assumptions of the model are these: A network of regulatory genes co-ordinates the synthesis of four structural proteins, which associate in distinct heterodimers that form a heterotetramer. Mutation in cis-regulatory regions produces transitions among 64 types of network. In a population, each network reproduces in proportion to its fitness, which depends on its probability (reliability) of synthesizing the tetramer. Fitness-dependent attrition keeps the size of the population constant. Regulatory genes occur in a sequence of levels; each level is associated with a different family of transcription factors. The following results emerge: Because different messengers within a family can give networks with the same connectivity, the 64 types of networks cluster into eight equivalence classes. During evolution with a low mutation rate, high-fitness classes can be approached through various paths on a fitness landscape. With a higher mutation rate, networks remain more uniformly distributed among the 64 types, and lower-fitness networks remain preponderant. An initially homogeneous population becomes more heterogeneous through mutation, but selection according to fitness later reduces its diversity. During this process the dispersion of the population over the possible networks increases, then decreases as the population approaches a unique steady state.

Protective effects of ranolazine in guinea-pig hearts during low-flow ischaemia and their association with increases in active pyruvate dehydrogenase

1. In isolated Langendorff-perfused, electrically-paced, hearts of guinea-pigs, global low-flow-ischaemia (LFI; at 0.7 ml min-1) resulted in marked increases in the rates of release of lactate, lactate dehydrogenase (LDH) and creatine kinase (CK) over a 30 min period. At the end of the LFI period, tissue ATP content was significantly reduced from a control value of 11.8 +/- 0.8 (5) to 5.6 +/- 0.8 (5) mumol g-1 dry weight. 2. The presence of ranolazine [(+/-)-N-(2,6-dimethyl-phenyl)-4[2-hydroxy-3-(2-methoxy-phenoxyl)- propyl] - l-piperazine acetamide dihydro-chloride; RS-43285-193] at 10 microM, from 20 min prior to and during LFI, resulted in significant reductions in the release of lactate, LDH and CK during the ischaemic period and a significant preservation of tissue ATP (9.0 +/- 1.1 (6) mumol g-1 dry wt.). Ranolazine did not prevent the reductions in creatine phosphate or glycogen observed in LFI, nor did it have any significant effects on any contractile parameters before or during the LFI period. 3. Neither ranolazine nor LFI affected the total amounts of tissue pyruvate dehydrogenase (PDH) activity; however, the significant reduction in the amount of active, non-phosphorylated PDH caused by LFI (from 88.2 +/- 5.5 to 44.2 +/- 3.2% of total activity) was partially but significantly prevented by ranolazine (67.2 +/- 6.8%). This effect of ranolazine on PDH may be part of the mechanism whereby the compound reduces lactate release and preserves tissue ATP during ischaemia.

Stimulation of specific immune responses to simian immunodeficiency virus using chimeric hepatitis B core antigen particles

Subunit approaches to vaccines against viral diseases have resulted in the development of a number of methods for presentation of defined epitopes to the immune system. We have exploited a highly immunogenic presentation system based on hepatitis B core antigen (HBcAg) particles to produce a number of candidate vaccines against simian immunodeficiency virus (SIV). Recombinant particles have been produced in bacteria which carry multiple copies of defined or predicted neutralizing epitopes of SIV at a number of different sites within the particle. In parallel, a number of synthetic peptide-based SIV vaccines have been produced based on homology to reported neutralizing epitopes in human immunodeficiency virus. Although potent immune responses were elicited against both particulate and peptide forms of the antigen, neutralizing antibodies were not induced as judged by available assays.

Haemolysis following mitral valve repair

We report the unusual occurrence of severe intra-vascular haemolysis following mitral valve repair. Mild to moderate mitral regurgitation was detected after repair, but severe haemolysis was the only indication for re-operation. Following prosthetic valve replacement there was an immediate cessation of haemolysis. We postulate that a small regurgitant jet directed against the teflon pledgets used in the repair was the reason for the haemolysis.

Urethral instability

Urethral instability is still evolving as a clinical entity. Using pressure variation of 15 cm water or more at the point of maximum urethral pressure (MUP), urethral pressure profilometry on patients referred for urodynamic assessment for lower urinary tract symptoms revealed urethral instability in 6.4% of 608 patients. The close association between urethral and detrusor instability was noted. Urethral instability appears to be a cause of frequency and urgency of micturition, and its presence increase the risk of urinary incontinence.

Targeting deletion (homoeologous chromosome pairing locus) or addition line single copy sequences from cereal genomes

We describe here a protocol for obtaining clones containing sequences present in low copy-number from genomic DNA where moderately and highly repeated sequences predominate. Specific chromosomal regions can be targeted by using deletion or addition line material. We have used this protocol to identify a sequence which has been deleted in both the tetraploid and hexaploid wheat mutants for the homoeologous chromosome pairing locus.

Retardation by aminoguanidine of development of albuminuria, mesangial expansion, and tissue fluorescence in streptozocin-induced diabetic rat

This study evaluated the relationship between the development of fluorescence related to advanced glycosylation end products (AGEs) in the kidney and experimental diabetic nephropathy over a 32-wk period. Control, untreated diabetic, and aminoguanidine-treated diabetic rats were followed for 32 wk with eight weekly measurements of urinary albumin excretion. After 32 wk, collagen-related fluorescence in aorta and kidney (whole kidney, isolated glomeruli, and renal tubules) and glomerular ultrastructure were evaluated. Diabetes was associated with a significant increase in collagen-related fluorescence in the aorta and kidney. Aminoguanidine prevented the increases in collagen-related fluorescence in aorta, isolated glomeruli, and renal tubules but not in whole kidney. Diabetes was associated with increased albuminuria, fractional mesangial volume, and glomerular basement membrane (GBM) thickness. Aminoguanidine attenuated the rise in albuminuria and prevented mesangial expansion without influencing GBM thickness in diabetic rats. The concomitant changes in collagen-related fluorescence, albuminuria, and mesangial expansion with aminoguanidine therapy are consistent with the hypothesis that AGEs may play a role in the development of diabetic nephropathy.

RS 30026: a potent and effective calcium channel agonist

1. A series of dihydropyridine derivatives has been evaluated for calcium channel agonist activity using reversal of nisoldipine-induced inhibition of beating of aggregates of embryonic chick myocytes. This test appears to be specific for calcium channel agonists since isoprenaline and cardiac glycosides are inactive. 2. RS 30026 was the most potent of the series, was significantly more potent than CGP 28392 and of similar potency to Bay K 8644 (pEC50 = 7.45, 6.16 and 7.20, respectively). RS 30026 increased edge movement of individual aggregates, in the absence of nisoldipine, by 50% at 2 nM. 3. Compounds were also evaluated for their effects on guinea-pig papillary muscle and porcine coronary artery rings. RS 30026 displayed positive inotropism at concentrations between 10(-9) and 10(-6) M (pEC200 = 8.21), but was a much more powerful inotrope than Bay K 8644, increasing contractility to 1300% of control at 10(-6) M (compared to 350% of control for Bay K 8644). RS 30026 caused vasoconstriction at concentrations between 10(-10) and 10(-7) M. 4. Calcium channel currents in single embryonic chick myocytes were recorded by whole-cell voltage clamp techniques. RS 30026 (100 nM-500 nM) produced large increases in peak current amplitude and shifted the voltage for threshold and maximal currents to more negative values. RS 30026 (500 nM) also produced large increases in the inward tail currents evoked upon repolarization. The effects of Bay K 8644 (50 and 500 nM) were much less marked. 5. Analysis of the activation characteristics of currents showed parallel shifts in the activation curve to more negative potentials in the presence of 50 nm Bay K 8644, with a much smaller shift in the presence of 500nm Bay K 8644. RS 30026 (100 and 500nM) caused concentration-dependent shifts in the activation of the calcium channel currents with an increase of the slope of the curve. 6. RS 30026 appears to be the most potent and effective calcium channel agonist described to date.

A high-molecular-weight fraction of smooth lipopolysaccharide in Klebsiella serotype O1:K20 contains a unique O-antigen epitope and determines resistance to nonspecific serum killing

The lipopolysaccharide (LPS) O-antigen side chains of Klebsiella serotype O1 have been studied by using mutants selected by resistance to a Klebsiella bacteriophage designated O1-A. Two classes of LPS mutants were identified. The major group (90%) synthesized rough LPS. The remaining 10% of the mutants produced a novel LPS profile that lacked the highest-molecular-weight O-substituted molecules (HMW-LPS) but still produced lower-molecular-weight O-substituted species (LMW-LPS). By using antisera raised against mutant Klebsiella strains and antiserum specific for Pasteurella haemolytica serotype 4, it was demonstrated that HMW-LPS and LMW-LPS contain shared epitopes. HMW-LPS also contained an epitope absent in LMW-LPS. This unique epitope was recognized by a monoclonal antibody (O1-52.6) and appears to be responsible for the serological cross-reaction between the O antigens of Klebsiella O1 and Escherichia coli O19. This HMW-LPS epitope was present in eight other Klebsiella O1 isolates which were examined. Electron microscopy demonstrated that HMW-LPS excluded overlying capsular polysaccharide for a distance of 25 to 40 nm. The distance was reduced to 10 to 18 nm in strains which synthesized only LMW-LPS and to zero in rough LPS strains. The HMW-LPS of Klebsiella O1 was shown to be an important virulence determinant, since this molecule was responsible for the resistance of the bacterium to nonspecific, complement-mediated serum killing.

Therapy for symptoms in the carcinoid syndrome

The clinical course and results of drug treatment for manifestations of the carcinoid syndrome are reviewed in 63 patients. The five-year actuarial survival in this group of patients was 48 per cent. The only markers of a poor prognosis that could be identified at diagnosis were marked weight loss and a high (over 1000 mumol/day) 5-hydroxyindole acetic acid excretion. The relative effectiveness of well-established drugs that either block 5-hydroxytryptamine synthesis or block 5-hydroxytryptamine receptors is reported, with respect to the different manifestations of the syndrome, and compared with a small group of patients treated with long-acting somatostatin analogue. In over one-third of patients, primary tumours were not detected on initial investigation, and in none of these did symptoms referrable to the primary site become apparent later.

Efficacy and safety of adenosine in the treatment of supraventricular tachycardia in infants and children

One hundred and seventeen episodes of supraventricular tachycardia in 50 children, including 28 infants, were treated with intravenous adenosine. Adenosine was prepared in a sterile solution of 0.9% saline (1 mg/ml) and given in incremental doses of 0.05 mg/kg every two minutes to a maximum of 0.25 mg/kg. Ninety of the 117 episodes were terminated. This included 88 of the 102 episodes of junctional tachycardia (79 of the 92 episodes of atrioventricular reentry tachycardia, seven of the eight episodes of atrioventricular nodal reentry tachycardia, and both of the episodes of long R-P' tachycardia). Only one of four episodes of His bundle tachycardia and one of the eight episodes of ectopic atrial tachycardia were terminated. None of the three episodes of atrial flutter were terminated. Side effects were frequent but mild and included transient complete atrioventricular block (less than 6 s), sinus bradycardia (less than 40 s), ventricular extrasystoles, flushing, nausea, headache, and respiratory disturbance. Reinitiation (within 5 s) of supraventricular tachycardia occurred in 13 of the terminated episodes. Although reinitiation limited its clinical efficacy in some patients, intravenous adenosine offered a safe and efficient method of rapid termination of most episodes of supraventricular tachycardia and in some cases facilitated diagnosis of the mechanism.

In vitro susceptibility studies of vancomycin-resistant Enterococcus faecalis

Vancomycin resistance exhibited by Enterococcus faecalis isolates V583, V586, and V587 is described. The vancomycin MICs ranged from 32 to 64 micrograms/ml. Although resistant to vancomycin, the isolates were susceptible to teicoplanin (MIC, less than or equal to 0.5 micrograms/ml). Such a glycopeptide susceptibility profile has not been previously described for E. faecalis. Time kill studies showed that vancomycin resistance adversely affected the synergistic activity that vancomycin and aminoglycoside combinations usually demonstrate against enterococci. However, the ability to detect vancomycin resistance varied with the susceptibility testing method used. Whereas broth microdilution, broth macrodilution, and agar dilution methods detected resistance, disk-agar diffusion and the AutoMicrobic system Gram-Positive GPS-A susceptibility card (Vitek Systems Inc., Hazelwood, Mo.) did not. To detect vancomycin resistance reliably and establish the incidence of such E. faecalis isolates, adjustments in some susceptibility testing methods may be necessary.

The tricuspid valve: an unusual site of endocardial pacemaker lead fracture

Two patients are described in this article who developed fractures of transvenous endocardial pacing leads at the point of passage across the tricuspid valve. In one case life-threatening asystole occurred, emphasizing the potential seriousness of this complication.