Thiolation of transfer RNA in Escherichia coli varies with growth rate. We have used an affinity electrophoresis assay which when combined with Northern hybridization techniques permits us to estimate the degree of thiolation of individual tRNA species in Escherichia coli. We observe that the levels of 4-thio 2'(3')-uridine (4-thioU) in many but not all tRNAs varies dramatically at different bacterial growth rates: Five tRNAs are completely thiolated at all growth rates, while another eight tRNAs are incompletely thiolated and the fraction of the unthiolated form of these tRNA species increases as the growth rates increase. Transfer RNA(2Glu) contains 4-thioU as well as (methylamino)methyl-2-thio uridine (mnm(5)2-thioU). The level of mnm(5)2-thioU of tRNA(2Glu) is invariant with growth rate. Surprisingly, none of the thirteen tRNA species that we have studied is completely unmodified in all growth media. In particular, at the slowest growth rates every tRNA class that we have studied contains a form that has 4-thioU residues.


Preparation of 13C and 15N labelled RNAs for heteronuclear multi-dimensional NMR studies. A procedure is described for the efficient preparation of isotopically enriched RNAs of defined sequence. Uniformly labelled nucleotide 5'triphosphates (NTPs) were prepared from E.coli grown on 13C and/or 15N isotopically enriched media. These procedures routinely yield 180 mumoles of labelled NTPs per gram of 13C enriched glucose. The labelled NTPs were then used to synthesize RNA oligomers by in vitro transcription. Several 13C and/or 15N labelled RNAs have been synthesized for the sequence r(GGCGCUUGCGUC). Under conditions of high salt or low salt, this RNA forms either a symmetrical duplex with two U.U base pairs or a hairpin containing a CUUG loop respectively. These procedures were used to synthesize uniformly labelled RNAs and a RNA labelled only on the G and C residues. The ability to generate milligram quantities of isotopically labelled RNAs allows application of multi-dimensional heteronuclear magnetic resonance experiments that enormously simplify the resonance assignment and solution structure determination of RNAs. Examples of several such heteronuclear NMR experiments are shown.


Preparation of isotopically labeled ribonucleotides for multidimensional NMR spectroscopy of RNA. A general method for large scale preparation of uniformly isotopically labeled ribonucleotides and RNAs is described. Bacteria are grown on isotopic growth medium, and their nucleic acids are harvested and degraded to mononucleotides. These are enzymatically converted into ribonucleoside triphosphates, which are used in transcription reactions in vitro to prepare RNAs for NMR studies. For 15N-labeling, E.coli is grown on 15N-ammonium sulfate, whereas for 13C-labeling, Methylophilus methylotrophus is grown on 13C-methanol, which is more economical than 13C-glucose. To demonstrate the feasibility and utility of this method, uniformly 13C-labeled ribonucleotides were used to synthesize a 31 nucleotide HIV TAR RNA that was analyzed by 3D-NMR. This method should find widespread use in the structural analysis of RNA by NMR.


Enhancement of ribozyme catalytic activity by a contiguous oligodeoxynucleotide (facilitator) and by 2'-O-methylation. RNA catalysts (ribozymes) designed to cleave sequences unique to viral RNA's might be developed as therapeutics. For this purpose, they would require high catalytic efficiency and resistance to nucleases. Reported here are two approaches that can be used in combination to improve these properties. First, catalytic efficiency can be improved by oligonucleotides (facilitators) that bind to the substrate contiguously with the 3'-end of the ribozyme. Second, 2'-O-methylation of flanking sequences of the ribozyme increases catalytic activity as well as resistance to nucleases. In combination with a facilitator oligodeoxynucleotide, the cleavage rate was increased 20 fold over that of the unmodified ribozyme.


Interaction of the antibiotics clindamycin and lincomycin with Escherichia coli 23S ribosomal RNA. Interaction of the antibiotics clindamycin and lincomycin with Escherichia coli ribosomes has been compared by chemical footprinting. The protection afforded by both drugs is limited to the peptidyl transferase loop of 23S rRNA. Under conditions of stoichiometric binding at 1 mM drug concentration in vitro, both drugs strongly protect 23S rRNA bases A2058 and A2451 from dimethyl sulphate and G2505 from kethoxal modification; G2061 is also weakly protected from kethoxal. The modification patterns differ in that A2059 is additionally protected by clindamycin but not by lincomycin. The affinity of the two drugs for the ribosome, estimated by footprinting, is approximately the same, giving Kdiss values of 5 microM for lincomycin and 8 microM for clindamycin. The results show that in vitro the drugs are equally potent in blocking their ribosomal target site. Their inhibitory effects on peptide bond formation could, however, be subtly different.


Arbitrarily primed PCR fingerprinting of RNA. Fingerprinting of RNA populations was achieved using an arbitrarily selected primer at low stringency for first and second strand cDNA synthesis. PCR amplification was then used to amplify the products. The method required only a few nanograms of total RNA and was unaffected by low levels of genomic double stranded DNA contamination. A reproducible pattern of ten to twenty clearly visible PCR products was obtained from any one tissue. Differences in PCR fingerprints were detected for RNAs from the same tissue isolated from different mouse strains and for RNAs from different tissues from the same mouse. The strain-specific differences revealed are probably due to sequence polymorphisms and should be useful for genetic mapping of genes. The tissue-specific differences revealed may be useful for studying differential gene expression. Examples of tissue-specific differences were cloned. Differential expression was confirmed for these products by Northern analysis and DNA sequencing uncovered two new tissue-specific messages. The method should be applicable to the detection of differences between RNA populations in a wide variety of situations.


Plasmid cDNA-directed protein synthesis in a coupled eukaryotic in vitro transcription-translation system. A system is described in which transcription of cDNA clones by bacteriophage T7 RNA polymerase is coupled to translation in the micrococcal nuclease treated rabbit reticulocyte lysate in a single reaction of coupled transcription-translation. The monovalent and divalent cation requirements for translation are dominant for optimum expression in this coupled system, so that transcription is relatively inefficient. Nevertheless, the use of appropriate DNA concentrations leads to the synthesis of sufficient RNA to saturate the protein synthesis capacity of the system. The fidelity and efficiency of expression in this coupled system are high, and the degree of purification of the plasmid DNA is relatively uncritical. The system therefore offers very considerable advantages for rapid screening of 'mini-preparations' of cDNA plasmid constructs for retention of the correct reading frame and expression of the desired protein product.


A comprehensive classification of nucleic acid structural families based on strand direction and base pairing. We propose a classification of DNA structures formed from 1 to 4 strands, based only on relative strand directions, base to strand orientation and base pairing geometries. This classification and its associated notation enable all nucleic acids to be grouped into structural families and bring to light possible structures which have not yet been observed experimentally. It also helps in understanding transitions between families and can assist in the design of multistrand structures.


A novel POU family transcription factor is closely related to Brn-3 but has a distinct expression pattern in neuronal cells. The use of the polymerase chain reaction in conjunction with degenerate oligonucleotides has allowed the isolation of cDNA clones derived from each of the POU family transcription factors expressed in the proliferating ND7 neuronal cell line. In addition to the previously characterized Oct-1, Oct-2 and Brn-3 factors, ND7 cells have been shown by this means to express a novel POU factor. This factor is closely related to Brn-3 but differs at seven amino acids in the POU domain, one of which is located in a region which is critical for protein-protein interactions between different POU proteins. Like Brn-3, the novel factor is expressed at high levels in embryonic brain and declines in abundance during neuronal development. In contrast to Brn-3 however, it is absent in mature sensory neurons and its expression declines during the in vitro differentiation of ND7 cells to a non-dividing phenotype whilst Brn-3 expression increases. The significance of these distinct but overlapping expression patterns is discussed in terms of the possible role of these two factors in regulating neuronal gene expression.


Characterization of the double stranded RNA dependent RNase activity associated with recombinant reverse transcriptases. An in situ gel assay was applied to the study of double stranded RNA dependent RNase activity associated with reverse transcriptase (RT) of HIV-1 and murine leukemia virus. Polyacrylamide gels containing [32P] RNA/RNA substrate were used for electrophoresis of proteins under denaturing conditions. The proteins were renatured and in situ enzymatic degradation of 32P-RNA/RNA was followed. E. coli RNaseIII, but not E. coli RNaseH, was active in this in situ gel assay, indicating specificity of the assay to RNA/RNA dependent nucleases. Analysis of purified preparations of HIV-1 RT p66/p51 expressed in E. coli demonstrated an RNA/RNA dependent RNase activity comigrating with the large subunit (p66) of the enzyme. In addition, this activity of the RT was often accompanied by a contaminating RNA/RNA dependent RNase, with a molecular weight approximately 30,000 dalton identical to that of E. coli RNaseIII. As the p51 small subunit of HIV-1 RT and a mutant of RT p66/p51, at Glutamic acid #478, did not exhibit RNA/RNA dependent RNase activity, at least part of the active site of the RNA/RNA dependent RNase activity appeared to reside at the carboxy end of the molecule. As these RT proteins are also deficient of RNaseH, our results suggest overlapping or identical catalytic sites for degradation of the substrates RNA/DNA and RNA/RNA.


A comparison of the fidelity of copying 5-methylcytosine and cytosine at a defined DNA template site. 5-Methylcytosine has been postulated to be an endogenous mutagen in procaryotes and eucaryotes leading to base substitution hot spots, C-->T transitions, resulting from spontaneous deamination of mC to T. The possibility remains, however, that a second mechanism involving mispairing of mC with A might also contribute to base substitution mutagenesis via G-->A transitions. Stimulation of the G-->A mutational pathway could involve preferential misincorporation of dAMP opposite template mC compared to C. To investigate this possibility, we synthesized a sequence containing mC at a defined template location. We compared the fidelity of copying mC versus C and the efficiency of extending mismatched base pairs at the mC position using three DNA polymerases, AMV reverse transcriptase, Drosophila DNA polymerase alpha, and mutant Escherichia coli Klenow fragment containing no proofreading exonuclease activity. Significant differences in misinsertion and mismatch extension efficiencies were observed only for the case of AMV reverse transcriptase. AMV reverse transcriptase was observed to incorporate dAMP 4 to 5-fold more efficiently opposite mC than C. Favored extension of a 5-MeC.A over C.A mispair was also observed with a difference of about 3-fold. In contrast to AMV reverse transcriptase, Klenow fragment showed no significant difference when copying either mC or C sites or when extending mispairs involving mC and C. Incorporation of dAMP opposite either C or mC was barely detectable using pol alpha, although pol alpha has been observed to form A.C mismatches in other sequences. While we cannot completely exclude the possibility that dAMP might be incorporated opposite mC in preference to C, our results suggest that contributions of the G-->A pathway to mC mutagenic hot spots are likely to be minor, lending additional support to the model invoking deamination of mC.


Synthesis of backbone deuterium labelled [r(CGCGAAUUCGCG)]2 and HPLC purification of synthetic RNA. The chemical synthesis of backbone deuterium labelled [r(CGCGAAU*U*CGCG)]2 (U* = [5'-2H]U) is described. An efficient purification procedure was developed using a polymeric reverse phase (PRP) HPLC column at 60 degrees C. This procedure provided pure RNA dodecamer in the multi-milligram quantities (39% overall yield) necessary for dynamics studies using solid-state deuterium NMR. The purification method has been effectively applied to other RNA sequences and will assist biophysical studies which require relatively large quantities of RNA oligomers.


Chemical synthesis of a biologically active natural tRNA with its minor bases. The complete chemical synthesis of an E. coli tRNA(Ala) with its specific minor nucleosides, dihydrouridine, ribothymidine and pseudouridine, is reported. The method makes use of protected 2'-O-tertiobutyldimethylsilyl-ribonucleoside-3'-O-(2-cyanoethyl-N- ethyl-N- methyl)phosphoramidites. The exocyclic amino functions of the bases were protected by the phenoxyacetyl group for purines and acetyl for cytosine. The assembling has been performed on a silica support with coupling yield better than 98% within 2 min of condensation. Triethylamine tris-hydrofluoride allowed a clean and complete deprotection of the tBDMS groups. The synthetic tRNA(Ala) has been transcribed into cDNA by reverse transcriptase and sequenced. With E. coli alanyl-tRNA synthetase the alanyl acceptance activity and kcat/Km were 672 pmol/A260 and 6 x 10(4)M-1s-1, respectively.


Insertion of non-intron sequence into maize introns interferes with splicing. Transposable element (TE) insertion into or near plant introns can cause intron skipping and alternative splicing events, resulting in reduced expression. To explore the impact of inserted sequences on splicing, we added non-intron sequence to two maize introns and tested these chimeric introns in a maize transient expression assay. Non-intron sequence inserted into Adh1-S intron 1 and actin intron 3 decreased expression from the luciferase reporter gene; the insertion sites tested were not in intron regions thought to be essential for splicing. Alternatively spliced mRNAs were not observed in transcripts derived from the insertion variants. In contrast, addition of an internal segment of an intron to Adh1-S intron 1 resulted in normal splice site selection and efficient processing. Because the normal intron sequence (including the conserved splice junctions) was retained in all constructs, we hypothesize that added non-intron sequence can interfere with intron recognition and/or splicing.


A novel murine homeobox gene isolated by a tissue specific PCR cloning strategy. We have identified a novel homeobox gene, designated K-2, using a reverse transcription PCR cloning strategy. Sequence analysis reveals that the homeobox of K-2 is 77.6% homologous at the nucleotide level and 97% identical at the amino acid sequence level to another murine gene, S8. Homeodomain sequence comparisons indicate that K-2 and S8 represent a distinct subclass of paired type homeobox genes. Northern blot analysis of RNA from murine embryos and adult tissues identified multiple transcripts that are expressed in a developmentally specific and tissue restricted manner. Alternate splicing of K-2 at the 3-coding region leads to the inclusion of a chain terminating sequence. In addition, the developmental expression pattern of this gene at day 12 of gestation was determined by in situ hybridization. Expression was observed in diverse mesenchymal cells in craniofacial, pericardial, primitive dermal, prevertebral, and genital structures.


In search of a perfect partnership.

In search of a perfect partnership. There's no question that our partnership is a natural, given the technological emphasis in modern medicine. My comments are not intended as criticism, but offered in the spirit of broadening our mutual understanding. I believe that open communication will enhance our continued collaboration in this interdisciplinary effort and yield significant advances in medical science.


Assessment of long-term stability of chronic ventricular pacing thresholds in steroid-eluting electrodes. Sixteen patients with Medtronic 4003 steroid-eluting electrodes implanted in the ventricular position were followed over 5 years. In each patient a special type of Medtronic 2443 pacemaker was implanted to allow programming of output at 1.35 V. Chronic threshold values in these patients measured at an output of 1.35 V were stable over the first 18 months of follow-up. Mean values were: 0.06 +/- 0.03 msec at 6 months and 0.08 +/- 0.02 msec at 18 months; these did not differ from each other significantly. However, during the period from 18 to 36 months postimplantation, a significant increase in mean pacing threshold was observed: 0.08 +/- 0.02 msec at 18 months postimplantation versus 0.14 +/- 0.05 msec at 36 months (P < 0.01). After 36 months, the chronic pacing threshold remained stable until the end of the 5-year follow-up period. Further long-term study of chronic threshold behavior of steroid-eluting electrodes measured at low amplitudes is warranted.


Exercise induced fatal sinusoidal ventricular tachycardia secondary to moricizine. Moricizine has been touted as having a low incidence of proarrhythmic effects. We present a case of proarrhythmia from moricizine, which presented as exercise induced ventricular tachycardia, and review the literature suggesting that this antiarrhythmic drug shares the proarrhythmic profile of other agents with predominant type Ic action. We conclude that moricizine has certain clinical and electrophysiological features that resemble type Ic antiarrhythmic agents. Precautions similar to those used when prescribing other drugs of this type should be followed when prescribing moricizine, including predischarge exercise testing.


VDD pacing with a previously implanted single lead system. Three patients who had undergone implantation of a rate modulated, atrial sensitive RS4 pacemaker, with a single orthogonal lead underwent replacement of a depleted unit with a DDD pulse generator, reusing the original lead with an adapter that allowed conversion of the bipolar atrial electrode into unipolar configuration. The mean atrial electrogram amplitude was 1.8 mV and no significant atrial sensing defects were found during Holter monitoring. As the RS4 pulse generator is no longer available, continued VDD pacing is possible by replacing it with a DDD pulse generator using the previously implanted single lead system.


The importance of muscle relaxation in dynamic cardiomyoplasty. During the last decade dynamic cardiomyoplasty has been introduced as a new method to treat patients with severe heart failure. This procedure consists of the wrapping of the latissimus dorsi (LD) muscle around the heart with electrical stimulation of the muscle synchronous to cardiac contraction. The optimal pacing mode of the muscle, during the conditioning and working period of the LD muscle, is still unclear. The pace protocol, currently used worldwide, has a maximal number of muscle tetanic contractions of 100 per minute. Data are presented on the LD muscle contraction characteristics using that protocol. Both force measurements from six in situ stimulated goat LD muscles and x-ray evaluation of the movement of metallic clips on wrapped LD muscles in two patients were used. Results demonstrate that LD muscle force is well maintained at the maximal rate of 100 contractions per minute but relaxation is severely hampered. This may lead to diminished support of the failing heart and damage of the wrapped muscle. A pacing protocol is proposed using a lower maximal stimulation rate.


Effects of group interventions on cognition and depression in nursing home residents. The effects of cognitive-behavioral group therapy, focused visual imagery group therapy, and education-discussion groups on cognition, depression, hopelessness, and dissatisfaction with life were studied among depressed nursing home residents. Seventy-six depressed subjects with mild to moderate cognitive decline participated in nurse-led 24-week protocols. Data were collected 4 weeks before the interventions, 8 and 20 weeks after treatment initiation, and 4 weeks after treatment termination. There were no significant changes in depression, hopelessness, or life satisfaction scores for any of the three conditions. Participants in the cognitive-behavioral and focused visual imagery groups showed a significant improvement beginning 8 weeks after treatment initiation on cognitive scores. These findings are encouraging indications that cognitive-behavioral and focused visual imagery group therapies may reduce cognitive impairment in depressed nursing home residents with mild to moderate cognitive decline.


Paediatric day surgery.

Paediatric day surgery. An in-depth study of the experience of 10 children admitted for day surgery revealed that parents received little information before the admission and that this was not compensated for by the information given on admission. Most of the children underwent excessively long pre-operative fasts and only three out of the 10 children were actually discharged on the day of their operation.


Acute and chronic cycle length dependent increase in ventricular pacing threshold. Several factors have been shown to influence ventricular pacing threshold in humans, including pacing lead location (endocardial vs epicardial), lead maturation, and antiarrhythmic agents. To determine whether ventricular pacing rate has a significant influence on acute and chronic pacing thresholds, we measured pacing thresholds in 16 patients receiving an implantable antitachycardia pacemaker cardioverter defibrillator (Cadence). Ventricular pacing thresholds were determined using the device programmer at cycle lengths of 600, 400 and 300 msec at the time of implantation; prior to hospital discharge at 3-14 days; and during follow-up outpatient visits at 6-8 weeks, 3 months, and 6 months to 1 year. Eleven patients had an epicardial lead system and five an endocardial lead system. Eleven patients were being treated with antiarrhythmic drug therapy. Device output ranged from 1-10 V and was adjustable in 1-V increments (pulse width was held constant at 1 msec). A cycle length dependent increase in pacing threshold (defined as a > or = 1-V increase in threshold at 400 or 300 msec relative to 600 msec) was observed in 10/16 patients during 12/72 pacing trials at 400 msec, and in 15/16 patients during 31/67 trials at 300 msec. In trials in which an increase in pacing threshold occurred, the magnitude of the increase at 400 msec relative to 600 msec was only 1 V in all 12 trials, but at 300 msec the increase ranged from 4-9 V in 7/31 (23%) trials.(ABSTRACT TRUNCATED AT 250 WORDS)


The effects of type I antiarrhythmic drugs on the signal-averaged electrocardiogram in patients with malignant ventricular arrhythmias. The effects of type I antiarrhythmic drugs on the signal-averaged electrocardiogram (SAECG) were analyzed in 58 patients with inducible sustained monomorphic ventricular tachycardia. SAECGs were acquired before and after drug therapy. A total of 99 drug trials were analyzed (mean 1.7 per patient). Analysis of temporal domain parameters included the duration of the QRS complex (QRSD), the high frequency total duration of the filtered QRS complex (HFTD), the duration of the signal under 40 microV (D40), initial QRS (HFTD minus D40), and the root mean square amplitude (RMSA) of the terminal 40 msec of the QRS signal. Changes in temporal parameters failed to predict drug efficacy. There were, however, type-specific drug effects on the SAECG. With the exception of type IB drugs, all drugs increased the QRSD, HFTD, and D40. Type IC drugs caused more prolongation of the QRSD and HFTD than type IA, IB, and the combination of IA+IB drugs. Prolongation of the HFTD was related to prolongation of the late potential and the initial portion of the QRS complex. A preferential effect of these drugs on the late potential was not observed. Type IC drugs also caused more prolongation of ventricular tachycardia cycle length than type IA or IB drugs. However, the increase in ventricular tachycardia cycle length did not correlate with a change in the SAECG. In summary, type I antiarrhythmic drugs cause a global slowing of ventricular activation. Although analysis of the SAECG following drug therapy was not useful for predicting drug efficacy, drug induced changes in the SAECG may be helpful for categorizing antiarrhythmic agents.


Right-sided versus left-sided radiofrequency ablation of the His bundle. Radiofrequency (RF) ablation of the His bundle was attempted in 30 consecutive patients with atrial flutter or fibrillation. A 7 French quadripolar catheter with a 4-mm distal electrode was advanced from the right femoral vein (21 patients), or subclavian vein (two patients) and positioned across the tricuspid valve. Adequate His-bundle potentials were obtained in all patients. However, in six patients atrioventricular (AV) block could not be obtained after multiple (mean = 8) applications of RF energy from the conventional right-sided approach. In these patients the same catheter was advanced to record a His potential through a retrograde arterial approach. AV block was created in all patients with one to three applications of RF energy. The duration of the procedure was 22 to 90 minutes for the right-sided approach and 5 to 10 for the left-sided approach (P < 0.005). Subsequently, in seven patients a left-sided approach was used first. One to six applications of RF energy were required to create AV block. The radiation exposure time was 3 to 20 minutes. No complications occurred. RF ablation of the His bundle seems easier using a left-sided than a right-sided approach, reduces procedure and radiation time, and avoids recovery of conduction. These data suggest that a left-sided approach, in spite of requiring arterial catheterization, may be preferable to a right-sided approach.


Successful radiofrequency current catheter ablation of sustained ventricular tachycardia. We performed radiofrequency current catheter ablation in two patients with nonischemic sustained ventricular tachycardia (VT). In one patient, two morphologically distinct VTs were induced by electrical stimulation. One showed right bundle branch block pattern and the other left bundle branch block pattern. The earliest site of activation during each VT was determined at the septum of the right ventricle. However, these two sites were close to the His-bundle electrogram recording area. In the other patient, a VT with a left bundle branch block pattern occurred spontaneously after the administration of isoproterenol. The earliest site of activation during VT was determined at the outflow tract of the right ventricle. During tachycardia, radiofrequency current ablation (40 W x 30 sec) was delivered to the earliest site of activation. A few seconds after fulguration, each VT was terminated and additional radiofrequency currents were given near these sites. After the ablation, VT could not be induced by the electrical stimulations, nor did it recur. No side effects were observed and the atrioventricular conduction remained intact. We feel that nonischemic VTs could possibly be treated by using radiofrequency current catheter ablation.


Quality-of-life in patients treated with atrioventricular synchronous pacing compared to rate modulated ventricular pacing: a long-term, double-blind, crossover study. To investigate whether the preservation of atrioventricular (AV) synchronization matters for quality-of-life during pacemaker treatment we assessed 17 consecutive patients with high degree AV block and preserved sinus node function in a double-blind, long-term crossover study. A questionnaire with regard to cardiovascular symptoms, sleep disturbances, cognitive functioning, physical ability, social interaction, emotional functioning, and self-perceived health was completed after 2 months of atrial synchronous (DDD) and rate modulated ventricular pacing (VVI,R), respectively. A significant improvement in shortness of breath, dizziness and palpitations as well as an improvement of cognitive functioning was observed during DDD pacing. Nine patients preferred the DDD mode and three the VVI,R mode. The remaining five patients did not express any preference. The preference for the DDD mode was explained by a significant reduction of cardiovascular symptoms and an improved self-perceived health, physical ability, and psychological well-being during DDD pacing. All differences in quality-of-life parameters between the two modes of pacing favored the DDD mode and no adverse effects of this mode were found. Thus, the maintenance of AV synchrony adds further symptomatic relief compared to rate increase alone. The results indicate that DDD pacing is the preferred mode of pacing in patients with high degree AV block and preserved sinus node function.


Reproducibility of head upright tilt table test results in patients with syncope. Head upright tilt table testing is a promising technique for the evaluation and management of vasovagal (neuroregulatory) syncope. In order to determine the day-to-day reproducibility of results using this technique we performed head upright tilt table testing (with or without graded isoproterenol infusion) in 21 patients (12 males, 9 females, mean age 34 +/- 19.1 years). During the first tilt study a total of 14 patients experienced syncope (six during baseline tilt, mean tilt time 15.8 +/- 7 minutes, eight following tilt with graded isoproterenol infusion, mean tilt time 17.7 +/- 9 minutes) while seven were negative. During the second tilt study (performed 3-7 days following the first study) the results of the first study were duplicated in 19 patients (90%) (six during baseline tilt, mean time 17.5 +/- 8 minutes, eight following graded isoproterenol infusion, mean time 15.9 +/- 7 minutes), however the level of provocation required to provoke syncope differed from that needed in the initial test in five patients (24%). We conclude that the results of head upright tilt table testing with graded isoproterenol infusions can be duplicated in 90% of patients, although some day-to-day variability exists in the degree of provocation necessary to elicit a positive response.


Effects of chronotropic responsive cardiac pacing on ventilatory response to exercise in patients with complete AV block. To identify the effect of chronotropic responsive cardiac pacing on the ventilatory response to exercise, ten selected patients with complete atrioventricular block underwent paired cardiopulmonary exercise tests in fixed rate ventricular (VVI) and dual chamber (DDD) or rate responsive ventricular (VVIR) pacing modes. Compared to VVI pacing, DDD or VVIR pacing increased peak oxygen uptake (P < 0.005) and augmented anaerobic threshold (P < 0.001). In eight patients, dyspnea was the major symptom limiting exercise with VVI pacing and this was markedly attenuated with DDD or VVIR pacing. In all patients, ventilation (VE) and the ratio of ventilation to CO2 production (VE/VCO2) were consistently higher with VVI pacing during exercise. To compare the response of the two pacing modes at the same workloads in an aerobic condition, we measured ventilatory variables 1 minute prior to the anaerobic threshold obtained with VVI pacing. When DDD or VVIR pacing was compared with VVI pacing, VE and VE/VCO2 significantly decreased from 20.5 +/- 5.3 L/min to 18.3 +/- 5.0 L/min (P < 0.005) and from 35.9 +/- 5.8 to 31.9 +/- 5.0 (P < 0.001), respectively. Respiratory frequency rose significantly more with VVI pacing (P < 0.001) despite an unchanged tidal volume. Although peak VE did not differ between the two pacing modes, VE/VCO2 at the peak exercise increased significantly more with VVI pacing (P < 0.005). Respiratory frequency also rose more with VVI pacing (P < 0.005) and tidal volume did not change. This study suggests that chronotropic responsive cardiac pacing attenuates the exertional dyspnea by improving the ventilatory response to exercise as well as increasing the cardiac output in patients with complete atrioventricular block.


The effects of selective stellate ganglion manipulation on ventricular refractoriness and excitability. The effects of selective stellate ganglion stimulation or stellectomy on ventricular excitability were studied in 30 open chest mongrel dogs anesthetized with alpha-chloralose. The effective refractory period (ERP) and strength interval curves (stimulus intensity [S2] = twice the diastolic threshold [ERP], and 2, 3, 5, 7, and 14 mA) were determined using bipolar epicardial electrodes placed in the mid-anterior wall of the right ventricle (RV) and the mid-posterolateral wall of the left ventricle (LV) during left stellate ganglion stimulation (LSGSt, n = 8) or right stellate ganglion stimulation (RSGSt, n = 8), or after left stellectomy (LSGEx, n = 7) or right stellectomy (RSGEx, n = 7). LSGEx prolonged ERP-LV (172 +/- 9 vs 167 +/- 8 msec, P < 0.05) and ERP-RV (163 +/- 10 vs 158 +/- 14 msec, P < 0.05). RSGEx prolonged ERP-LV (168 +/- 17 vs 162 +/- 15 msec, P < 0.01) and ERP-RV (166 +/- 14 vs 160 +/- 13 msec, P < 0.01), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. LSGSt decreased ERP-LV (157 +/- 11 vs 163 +/- 12 msec, P < 0.01) and ERP-RV (147 +/- 18 vs 157 +/- 17 msec, P < 0.05), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. RSGSt did not significantly decreased ERP-LV (152 +/- 11 vs 156 +/- 9 msec); however, it significantly shortened the times of the strength interval curves obtained for S2 intensities of 2 and 7 mA in the LV, and shortened ERP-RV (139 +/- 10 vs 145 +/- 7 msec, P < 0.01) and the times of the strength interval curve for S2 intensities of 2, 3, and 5 mA in the RV. A significant interaction (MANOVA test) was observed between the ventricle studied and the ganglion stimulated for S2 intensities of 2 and 3 mA, and between the effect of stimulation and the ganglion stimulated for S2 intensities of 3 and 14 mA. To conclude, selective stellectomy prolonged epicardial ventricular refractoriness in both the mid-anterior wall of the RV and the mid-posterolateral wall of the LV; the magnitude of the epicardial excitability variations in both areas was different during selective stellate ganglion stimulation.


Atrial arrhythmia management with sensor controlled atrial refractory period and automatic mode switching in patients with minute ventilation sensing dual chamber rate adaptive pacemakers. Although a long postventricular atrial refractory period (PVARP) may prevent the occurrence of pacemaker mediated tachycardias and inadvertent tracking of atrial arrhythmias in dual chamber (DDD) pacing, the maximum upper rate will necessarily be compromised. We tested the feasibility of using minute ventilation sensing in a dual chamber rate adaptive pacemaker (DDDR) to shorten the PVARP during exercise in 13 patients with bradycardias (resting PVARP = 463 +/- 29 msec) to avoid premature upper rate behavior. Graded treadmill exercise tests in the DDD and DDDR modes at this PVARP resulted in maximum ventricular rates of 98 +/- 8 and 142 +/- 3 beats/min, respectively (P < 0.0001), due to chronotropic incompetence and upper rate limitation in the DDD mode, both circumvened with the use of sensor. In order to stimulate atrial arrhythmias, chest wall stimulation was applied for 30 seconds at a rate of 250 beats/min at a mean unipolar atrial sensitivity of 0.82 mV. Irregular ventricular responses occurred in the DDD mode (the rates at a PVARP of 280 and 463 +/- 29 msec were, respectively 92 +/- 5 and 66 +/- 3 msec; P < 0.0001). In the DDDR mode at a PVARP of 463 +/- 29 msec, regular ventricular pacing at 53 +/- 2 beats/min occurred due to mode switching to VVIR mode in the presence of repetitive sensed atrial events within the PVARP. One patient developed spontaneous atrial fibrillation on follow-up, which was correctly identified by the pacemaker algorithm, resulting in mode switch from DDDR to regular VVIR pacing and preservation of rate response. In conclusion, sensor controlled PVARP allows a long PVARP to be used at rest without limiting the maximum rate during exercise. In addition, to offer protection against retrograde conduction, a long PVARP and mode switching also limit the rate during atrial arrhythmias and allow regular ventricular rate responses according to the physiological demands.


Evaluation of transesophageal atrial pacing stethoscope in adult surgical patients under general anesthesia. Sinus bradycardia (SB) and atrioventricular junctional rhythm (AVJR) commonly cause circulatory insufficiency in anesthetized surgical patients. Treatment is usually with drugs, which can be ineffective or have adverse effects. Cardiac pacing might be preferred, but the transvenous or epicardial routes are too invasive for routine use, and transcutaneous pacing fails to preserve atrial transport function. Transesophageal atrial pacing (TAP) lacks these disadvantages, yet unavailability of inexpensive products has prevented more widespread use. Therefore, a pacing esophageal stethoscope (PES) fabricated by addition of bipolar electrodes to disposable esophageal stethoscopes routinely used for intraoperative monitoring, was evaluated in 100 anesthetized adults. TAP thresholds (10-msec pulses) and hemodynamic effects of TAP as treatment for incidental SB (< or = 60 beats/min) or AVJR were determined. Minimum TAP thresholds (mean +/- standard error) in 48 males were 7.3 +/- 0.3 mA and in 51 females were 8.5 +/- 0.4 mA. Corresponding inferior alveolar ridge-to-electrode distances were 32.5 +/- 0.2 and 30.4 +/- 0.2 cm. For 48 patients with SB < or = 60 beats/min (54 +/- 1 beats/min), TAP (81 +/- 1 ppm) produced average 15, 11, and 14 mmHg increases in systolic, diastolic, and mean arterial pressure, respectively (P < 0.001). For 11 patients with AVJR (71 +/- 5 beats/min), TAP (92 +/- 3 ppm) produced average 23 and 15 mmHg increases in systolic and mean arterial pressure, respectively (P < 0.05). There were no apparent complications of TAP. TAP with a PES appears practical, safe, and effective for prophylaxis and treatment of SB or AVJR in anesthetized surgical patients.


Comparison of subxiphoid and traditional approaches for ICD implantation. We compared clinical and electrophysiological data in 18 patients undergoing ICD implantation via a traditional (median sternotomy or left lateral thoracotomy) with 29 patients with a subxiphoid approach. Both groups were similar in terms of age, sex, left ventricular ejection fraction, presence of coronary artery disease, and clinical indication for the device. Fifteen patients (83%) with the traditional approach had previous cardiac surgery compared with 6 patients (21%) who had a subxiphoid approach (P < 0.001). Both groups had similar patch R wave and sensing R wave measurements. Patients with the traditional approach had a lower energy for defibrillation than patients with a subxiphoid approach (13.6 +/- 6.8 J vs 17.9 +/- 4.1 J, P < 0.05). Postoperative hospital days were fewer in the subxiphoid group compared with the traditional approaches (9.8 +/- 5.3 vs 13.7 +/- 7.5 days) but the differences did not reach statistical significance, possibly due to small numbers. The subxiphoid approach appears to be a reasonable alternative approach to the traditional approach in selected patients undergoing ICD implantation.


Clinical experience with a helical bipolar stimulating lead. Over 100 patients have been treated for partial epilepsy using a NeuroCybernetic Prosthesis System (NCP). The NCP System is comprised of an implantable pulse generator, an implantable bipolar stimulating lead, and an external communication system. The lead delivers electrical impulses from the NCP Generator to the vagus nerve, and includes a connector end that plugs into the generator, a silicone insulated lead body, and the helical electrode array that attaches to the nerve. The surgical implantation technique has a significant impact on lead reliability and performance. The lead electrode has performed well to date. Modifications to further improve reliability have been implemented. Clinical experience, case history examples, and voltage measurements are examined. The lead electrode is an important component of the overall system and plays a significant part in the success of vagus nerve stimulation therapy.


Treatment of refractory partial seizures: preliminary results of a controlled study. Vagus nerve stimulation for the treatment of epilepsy has been studied in medically refractory patients with partial seizures in a randomized, blinded, parallel study. After a 3-month baseline period, the patients were implanted with the Neurocybernetic Prosthesis (NCP) system consisting of the NCP Generator and the Bipolar Vagal Stimulation Lead. Two stimulation paradigms were used, HIGH, which delivers what is considered to be optimal stimulation parameters and LOW, which is considered to be less or noneffective. The system and vagus nerve stimulation were well tolerated and few adverse events have been attributed to either. One patient experienced a period of direct current to the nerve due to a generator malfunction. This results in paralysis of the left vocal cord. Efficacy analysis on the first 37 patients to complete the controlled portion of the study has shown that the patients in the HIGH group experienced a mean reduction in seizure frequency of 33.3% and patients in the LOW group experienced a mean reduction in seizure frequency of 8.4%. The difference between the groups is statistically significant with a P value of 0.025. Analysis of seizure duration and intensity does not show any significant change. Ratings of the patient's overall condition by the patient, investigator, and companion as a measurement of "quality of life" also show improvement in the HIGH group. The results of this interim study demonstrate that vagus nerve stimulation is a safe and effective method of treating partial epileptic seizures.


Chronic vagus nerve stimulation increases the latency of the thalamocortical somatosensory evoked potential. The Neurocybernetic Prosthesis (NCP) is a pacemaker-like device that has been designed to provide chronic intermittent vagus nerve stimulation. It is currently under study for the treatment of refractory partial onset epilepsy, and preliminary studies have indicated that partial onset seizures are improved by this therapy. The mechanisms by which it exerts its antiepileptic effect are not well understood. Although there are extensive pathways to the forebrain from the nuclei of the vagus nerve, the evidence that the NCP alters neural transmission outside the vagal system is limited. We prospectively examined somatosensory and brain stem auditory evoked potentials (BAEPs) in three patients receiving NCP implantation to determine if changes in these studies occur as a result of chronic vagus nerve stimulation. The results demonstrate a significant prolongation of the cervicomedullary to thalamocortical potential (N13-N20) interval on somatosensory evoked potential (SSEP) studies following activation of the device. No other significant changes were seen on SSEP or BAEP in the NCP implanted patients or normal controls. The findings suggest that chronic vagus nerve stimulation does alter neuronal networks outside of the brain stem vagus system, and may potentially provide a means to clinically monitor and titrate this therapy.


Neurocardiac responses to vagoafferent electrostimulation in humans. To determine if cardiac vagal tone is enhanced by vagal electrostimulation (VES), we examined the heart rate autospectrum (HRA) in eight patients with implanted stimulators for complex partial seizures. In four patients the VES was activated at 30 Hz and 500-msec pulse (HiStim group) compared to 2 Hz and 130-msec pulse for the LoStim group (n = 4). Continuous ECG and respiratory waveforms were recorded for 45 minutes every 8 hours (7-8 AM; 3-4 PM 11-12 PM) during resting supine wakeful epochs both before and 15 days after surgical implantation. From the HRA cardiac sympathovagal balance was expressed as the ratio of the low frequency (LF) power to the high frequency (HF) power. There were no presurgical differences between the groups in heart rate, its variance, or the energies contained in any autospectral band. The LoStim group showed no significant change in heart rate (HR), HF peak power, or LF:HF ratios during 2 weeks of VES. Conversely, in the HiStim group, the LF:HF peak power ratio (an expression of sympathetic dominance) decreased from 2.5 +/- 1.5 preimplant to 1.5 +/- 0.49 (P < 0.02) with VES. During VES there was a significantly higher HF power in the HiStim compared to LoStim group. No diurnal variations in HRA values were seen for either group. (1) A relationship exists between selective vagal nerve electrostimulation and the HRA; and (2) high stimulation frequency of the vagus nerve in man is associated with sustained augmentation of cardiac vagal tone throughout a 24-hour cycle.


Effects of chronic left vagal stimulation on visceral vagal function in man. We examined the effects of chronic left vagal electrostimulation on afferent and efferent gastrointestinal vagal function in eight patients. Afferent function was assessed using cortical evoked responses to electrical stimulation of the esophagus and to direct vagal stimulation using the implanted left vagal electrode. Efferent gastrointestinal vagal function was measured by examining the basal, maximal, and sham fed stimulated gastric acid output prior to and with chronic left vagal electrostimulation. Esophageal electrostimulation produced a cortical evoked response consisting of three negative and three positive peaks within 400 msec after stimulation. Prior to vagal electrostimulation the mean conduction velocity of the afferent signal was measured at 8.72 +/- 3.39 m/sec, compatible with A-delta fibers involvement. Basal, maximal, and sham fed acid output were 1.11, 21.87, and 9.37 mmol/hour, respectively. The evoked response to esophageal electrical stimulation was not changed with chronic left vagal electrostimulation. Direct vagal stimulation also produced evoked potentials that were comparable to those obtained with esophageal stimulation. The mean conduction velocity was 6.26 +/- 2.72 m/sec (NS) so that there was no evidence of loss of myelinated fibers with chronic stimulation. No differences were detected in basal (1.29 mmol/h), maximal (21.64 mmol/h), or sham fed stimulated (8.03 mmol/h) acid output, showing that vagal electrostimulation has no effect on either total or vagally mediated acid output, an efferent vagal function. In conclusion, chronic left vagal electrostimulation has no significant adverse effect on gastrointestinal vagal function.


Evidence of impaired afferent vagal function in patients with diabetes gastroparesis. Two patients, a 28-year-old male and a 70-year-old female, with chronic insulin dependent diabetes mellitus and evidence of autonomic neuropathy were studied using cortical evoked responses following esophageal balloon and electrical stimulation. Both patients had symptomatic gastroparesis, poor gastric emptying, and reduced gastroduodenal motility including abnormal results of scintigraphy and manometry. There was slowing of afferent vagal conduction but good evoked potential responses were recorded even though one patient could not feel electrical stimulation of either the proximal or distal esophagus. It is improbable that the gastric symptoms are due to an afferent autonomic neuropathy, but symptoms may well be related to impairment of motor vagal pathways. Nevertheless, afferent vagal pathways are involved in severe diabetes mellitus. The clinical significance of this delay in conduction velocity of afferent pathways remains to be established.


Cognitive motor function after electrical stimulation of the vagus nerve. Chronic stimulation of the vagus nerve does not seem to produce significant differences between high frequency and low frequency stimulation groups. Individuals within each group show significant changes between preoperative assessment and after 6-month stimulation. Some subjects showed significant improvement and some showed significant slowing of responses. Subjects who showed improvement are still considerably slower than normals, but all patients have a very long history of complex partial seizures and exposure to multiple medications. Larger homogeneous sample sizes are needed to delineate more clearly the correlation between cognitive performance, medication effects, and stimulation effects.


Acute effects of high frequency vagal nerve stimulation on balance and cognitive motor performance in epilepsy: three case study reports. Quantitative measures of area of sway, total sway, and cognitive function failed to show significant differences in acute (50 minute) "ON-OFF-ON-OFF" studies of high frequency left vagal stimulation in three epileptic patients undergoing treatment for chronic complex partial seizures. Fluctuation in blood levels of anticonvulsants may have been associated with some clinical effects. There were no significant adverse effects of acute left vagal stimulation in these three subjects.


Electrostimulation effects of the vagus nerve on balance in epilepsy. Preliminary results of selected postural measures in quiet standing indicate that stimulation of the vagus nerve appears not to be producing adverse effects. With this specific sample size, more testing is needed to determine long-term effects and future data analyses will examine correlations between electroencephalogram results, drug levels, and seizure frequency. In the present study three subjects have had old injuries to hips and ankles. Two subjects had normal values for postural control prior to stimulation, while other subjects were severely abnormal. In future, studies should include larger homogeneous sample sizes, as the current subjects show marked variability in age and premorbid health backgrounds. Future work should also control more vigorously for variables such as visual input (i.e., blindfolding subjects instead of simply closing the eyes). Evaluation of postural control mechanisms will be continued to assess stability changes in these patients as seizure frequency continues to subside.


Hemothorax associated with anticoagulation after placement of implantable cardioverter defibrillator: possible similarity to postinfarction Dressler's syndrome. Massive hemothorax developed after placement of an implantable cardioverter defibrillator (ICD) in two patients who received postoperative anticoagulants. The possible relationship of this complication to polyserositis after ICD implantation is discussed as are the possible adverse sequelae of early anticoagulation after ICD implantation.


Ventricular lead transection and atrial lead damage in a young softball player shortly after the insertion of a permanent pacemaker. We report a case in which permanent pacemaker implantation using a conventional subclavian approach on the throwing side of an avid softball player resulted in complete transection of the ventricular lead and severe damage to the atrial lead. The site of the lead fracture suggested that both leads were crushed between the clavicle and the first rib as a result of the frequent and repetitive arm movement. This case illustrates the importance of the selection of the correct approach for permanent pacing lead insertion.


A technique utilizing a steerable hydrophilic guidewire for permanent pacemaker implantation. We report the use of a steerable hydrophilic guidewire for permanent pacemaker implantation. This wire, previously used for peripheral vascular and cardiac angiography, is able to be steered and passed in many situations when a standard guidewire cannot be used. We report three cases where the standard J-tipped guidewire could not be passed by either the cephalic or subclavian route and the hydrophilic guidewire allowed for successful atraumatic placement of a sheath and pacemaker lead.


Supernormal conduction in the left bundle branch unmasked by the linking phenomenon. This presentation reflects a case of phase-3 left bundle branch block (LBBB). Analysis reveals that relatively early QRS complexes are wide, whereas beats occurring later than a critical time are narrow. There are, however, two unexpected phenomena: (1) an overlap occurs between the range of R-R intervals resulting in normal intraventricular conduction and the range of R-R intervals resulting in LBBB pattern. Complexes that follow a wide beat are often wide although they are associated with relatively long R-R intervals, whereas complexes that follow a normal beat tend to be normal even after relatively short R-R cycles. This is due to concealed retrograde penetration of the bundle branch that is blocked in anterograde direction (the so-called linking phenomenon). (2) Some early supraventricular impulses, paradoxically, resulted in normal intraventricular conduction. The phenomenon is a manifestation of supernormal LBB conduction, and only occurs following a wide QRS complex associated with retrograde activation of the LBB. The linking phenomenon reveals or unmasks the supernormal phase of LBB conduction. Following a retrograde and delayed activation of the LBB, the refractory period of the bundle branch is postponed, in such a way that a supraventricular impulse is allowed to occur during the early phase of supernormal conduction.


Failure of defibrillator paddle as mimic for subcutaneous patch lead during nonthoracotomy implantable cardioverter defibrillator lead configuration assessment. It is a common, although virtually unsubstantiated, practice to assess the efficacy of nonthoracotomy lead systems for implantable cardioverter defibrillators using a defibrillator paddle as mimic for the subcutaneous patch lead. We report a case in which an adequate defibrillation threshold was documented with the nonthoracotomy lead system using a defibrillator paddle but not following implantation of the true subcutaneous patch lead. This case suggests that the substitution of a defibrillator paddle for the subcutaneous patch lead during nonthoracotomy lead system evaluation may have significant limitations in assessing lead configuration efficacy.


Programmable external automatic antitachycardia pacing as a bridge to definitive therapy in patients with recurrent sustained ventricular tachycardia. The efficacy and safety of external programmable automatic antitachycardia pacemakers (ATPs) used in the critical care setting for recurrent sustained monomorphic ventricular tachycardia (VT) was evaluated. Ten patients who had failed a mean of 4.0 +/- 1.4 antiarrhythmic medications (range 2-7) and who had previously required electrical cardioversion for VT were enrolled. Prior to ATP use, successful overdrive pacing termination of VT was demonstrated in all patients. Intertach (Intermedics, Inc.; n = 9) and Orthocor II (Cordis, Inc.; n = 1) ATPs were attached to temporary bipolar transvenous or epicardial pacing leads. Mean patient age was 66.4 +/- 11.5 years, and mean left ventricular ejection fraction was 22 +/- 7.5%. At the time of initial ATP use, mean VT cycle length was 347 +/- 88 msec (range 280-550 msec). A burst scanning antitachycardia pacing algorithm was used in each patient; one patient was also treated with a fixed rate burst adapted to VT cycle length. The duration of ATP use ranged from 2-25 days (median 5), successfully terminating greater than 3,369 VT episodes (median 3, range 0 to greater than 3,103 episodes per-patient). Two episodes of ATP induced rate acceleration occurred, each successfully terminated by the ATP. Only two patients required external cardioversion during ATP use, one for primary ventricular fibrillation and one for rapid polymorphic VT associated with antiarrhythmic drug withdrawal. ATPs also provided antibradycardia pacing and allowed for serial programmed ventricular stimulation. No complications were associated with transvenous catheter or ATP use.(ABSTRACT TRUNCATED AT 250 WORDS)


Radiofrequency ablation of bilateral quadruple accessory pathways in a patient with Wolff-Parkinson-White syndrome. A patient with drug refractory supraventricular tachycardia showed electrophysiological evidence of bilateral quadruple accessory pathways. The conduction was bidirectional in the left posteroseptal and left posterolateral accessory pathways, antegrade in the right lateral accessory pathway, and retrograde in the right anterior accessory pathway. The four pathways participated in seven types of reciprocating tachycardias. Radiofrequency ablation eliminated the four pathways successfully. The patient was asymptomatic and free of any drug during a 10-month follow-up.


Comparison of clinical benefits and outcome in patients with programmable and nonprogrammable implantable cardioverter defibrillators. Technological advances in implantable cardioverter defibrillators (ICDs) have provided a variety of programmable parameters and antitachycardia therapies whose utility and impact on clinical outcome is presently unknown. ICDs have capabilities for cardioversion defibrillation alone (first generation ICDs), or in conjunction with demand ventricular pacing (second generation ICDs), or with demand pacing and antitachycardia pacing (third generation ICDs). We examined the pattern of antitachycardia therapy use and long-term survival in 110 patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Group I included 62 patients with nonprogrammable first generation ICDs that delivered committed shock therapy after ventricular tachyarrhythmia detection based on electrogram rate and/or morphology was satisfied. Group II included 48 patients with multiprogrammable ICDs (including second and third generation ICDs) that had programmable tachyarrhythmia detection based on rate and tachycardia confirmation prior to delivery of electrical treatment with either programmable shocks and/or, as in the third generation ICDs, antitachycardia pacing. Incidence and patterns of antitachycardia therapy use and long-term survival were compared in the two groups. The incidence of appropriate shocks in patients who completed 1 year of follow-up was significantly greater in group I (30 of 43 patients = 70% vs 11 of 26 patients = 42%; P less than 0.05). In the total follow-up period, a significantly larger proportion of group I patients as compared to group II patients used the shock therapies (46 of 62 patients = 74% vs 25 of 48 patients = 52%; P less than 0.01), with the majority doing so within the first year of implantation (96% and 92%, respectively). Although the frequency of antitachycardia therapy activation was similar, the number of shocks delivered per patient was lower in group II, particularly in the initial 3 months of follow-up (P = 0.06). No clinical variable aided in identifying users from nonusers of antitachycardia therapy. Arrhythmic mortality was virtually eliminated in both groups. Two-year actuarial cardiac survival in the two groups was similar (group I = 78% vs group II = 84%; P greater than 0.2). Survival from cardiac mortality in users and nonusers of antitachycardia therapies was also similar in both groups (P greater than 0.2) and in the total patient group (P greater than 0.2). We conclude that programmable ICDs continue to confer advantages in prevention of sudden death that were observed with nonprogrammable ICDs and can be expected to improve patient tolerance and physician acceptance of device therapy for VT/VF.


Histologic findings of the heart and the conduction system in the first patient who underwent catheter ablation. This is a detailed pathological examination of the heart including the conduction system (CS) from a 64-year-old male who had catheter ablation of the atrioventricular (AV) junction for intractable atrial fibrillation. This is the world's first human who had this procedure, and who survived 3 years and 8 months, and later died of congestive heart failure. Pathologically, the heart was hypertrophied and enlarged. Histologically, there were chronic inflammatory cells, marked fatty metamorphosis with fibrosis of the atria, the approaches to the AV node, and the AV node, with almost isolation of the node from the atria, and considerable fibrosis of the bundle and bundle branches. In addition, there was fibrosis of the summit of the ventricular septum with chronic inflammatory cells. These represent the sequelae of the ablation procedures. It is not known how much of the pathological findings contributed to the cardiac hypertrophy and impairment of cardiac function.


Distinct activation patterns of idioventricular rhythms and sympathetically-induced ventricular tachycardias in dogs with atrioventricular block. To investigate mechanisms of ventricular impulse formation in response to sympathetic stimulation in the healthy canine heart in situ, we compared the patterns of ventricular activation during the idioventricular rhythms arising after complete atrioventricular (AV) block and ventricular tachycardias induced by RSG or LSG stimulation. Isochronal maps were generated by computer from 116-127 unipolar electrograms recorded from the entire ventricular epicardium in 15 open chest, anesthetized dogs. In eight of these, bipolar electrograms were recorded with plunge electrodes from 11 selected endocardial sites located below epicardial breakthrough areas. Intracardiac recordings from the His-Purkinje system were made with electrode catheters. After electrograms were recorded during sinus rhythm, complete AV block was induced by injecting formaldehyde into the AV node and idioventricular rhythms occurred spontaneously at a rate of 37 +/- 12 beats/min (mean +/- SD, n = 25). During idioventricular rhythms, endocardial activation preceded the earliest epicardial breakthrough, which occurred in either the right anterior paraseptal region, antero-apical left ventricle, or postero-apical left ventricle. These sites were consistent with a focal origin in the subendocardial His-Purkinje system. Total epicardial activation times lasted for 47 +/- 13 msec (n = 40). Idioventricular rhythms were suppressed by overdrive pacing (intermittent trains of ten beats with decremental cycle length from 500 to 200 msec) or by intravenous calcium infusion (to plasma levels of 10.1-15.2 mM). Right or left stellate ganglion stimulation increased idioventricular rhythm rates (to 52 +/- 13 beats/min, n = 28) and also induced, in all preparations, ventricular tachycardias that had significantly faster rates (189 +/- 55 beats/min, n = 27, P less than 0.005). Ventricular fibrillation was induced after brief runs of ventricular tachycardia in five of the preparations. During ventricular tachycardias, epicardial activation occurred on the right ventricular outflow tract or the postero-lateral wall of the left ventricle, and preceded endocardial activation in 50% of cases. Total epicardial activation times (103 +/- 29 beats/min) were significantly longer than during idioventricular rhythms (P less than 0.005). Ventricular tachycardias displayed overdrive excitation at critical pacing cycle lengths (360-280 msec) and were not suppressed by calcium infusion. Thus, differential mechanisms of impulse formation with distinct localizations can be elicited from healthy ventricular myocardium.


MATIC--an intracardiac tachycardia classification system. The use of an additional atrial sensing electrode together with a morphology recognition algorithm provides a significant improvement in classification performance over the current rate based algorithms used in implantable cardioverter defibrillator (ICD) devices. The classification system, called morphology and timing intracardiac classifier (MATIC), follows a classification process similar to that used by cardiologists. Timing between the atrial and ventricular channels is examined using a decision tree and forms the primary criterion for arrhythmia classification. A neural network based morphology classifier is used for cases such as ventricular tachycardia with 1:1 retrograde conduction where timing alone cannot make a reliable decision. MATIC achieves 99.6% correct classification on a database of intracardiac electrogram (ICEG) signals containing 12,483 QRS complexes recorded from 67 patients during electrophysiological studies. Arrhythmias in this database include sinus tachycardia, normal sinus rhythm, normal sinus rhythm with bundle branch block, sinus tachycardia with bundle branch block, atrial fibrillation (AF), various supraventricular tachycardias, ventricular tachycardia, ventricular tachycardia with 1:1 retrograde conduction, and ventricular fibrillation. Within these arrhythmias, there were numerous ventricular ectopic beats, fusion beats, noise, and other artifacts. MATIC addresses the classification problem from start to finish, inputs being raw intracardiac electrogram signals and the outputs being the recommended ICD therapy. Results achieved with MATIC were compared with a classifier used in the Telectronics Guardian ATP 4210, which achieved 75.9% correct classification on the same database. MATIC is simple and efficient, making it suitable for use in a low power implantable device.


Atrial fibrillation: epidemiology and the risk and prevention of stroke. Atrial fibrillation is a common disorder and the incidence increases with each decade of life. Previously, rheumatic mitral valve disease has been the condition most highly associated with atrial fibrillation. However, with the decreasing incidence of rheumatic heart disease, other conditions have assumed greater importance and now congestive cardiac failure, coronary artery disease, and hypertension are the most commonly associated conditions. Nonrheumatic atrial fibrillation is associated with an approximately five-fold increase in the risk of ischemic stroke and a 5% to 7% yearly risk that increases with age. In addition, atrial fibrillation is associated with an increased incidence of silent cerebral infarction and increased mortality. However, whether atrial fibrillation is independently associated with the risk of stroke or is a marker of underlying cardiac disease is contentious. Until recently, the use of preventive therapy has been controversial. However, data from four recently published, prospective randomized studies clearly support the use of warfarin prophylaxis in nonrheumatic atrial fibrillation. Within the diverse group of patients with nonrheumatic atrial fibrillation there are high and low risk subgroups and identification of these may influence decisions regarding antithrombotic prophylaxis. With a few exceptions, however, this remains an area in which there are contradictory findings in the literature. The role of aspirin for prophylaxis in nonrheumatic atrial fibrillation remains unclear and further evaluation awaits the publication of ongoing studies.


A case of hidden receptacle-adapter incompatibility. Connection of a universal VS-1 adapter to a VS-1 receptacle resulted in intermittent loss of pacing and of sensing in a pacemaker dependent patient. This was caused by the use of an adapter that only provides stable electric contact if the adapter pin is deformed by the set screw. Since we had implanted a pulse generator with a "side-lock" connector without screws, only a loose connection was achieved. The manufacturers should provide information on such hidden incompatibilities.


Surgical treatment of ventricular tachycardia with Nd:YAG laser photocoagulation. Directed surgery for the definitive treatment of drug resistant ventricular tachycardia (VT) due to coronary artery disease carries a significant operative mortality. Surgical failure to cure VT remains a problem, especially in patients without anterior left ventricular myocardial infarcts and aneurysms. A method has been developed in which Nd:YAG laser is used to photocoagulate myocardium responsible for the initiation of VT using a "sequential" approach intended to improve operative results and gain insight into the variable substrates causing VT. Under normothermic cardiopulmonary bypass, VT is induced and then extensive endocardial and epicardial mapping performed to localize and characterize that form of VT. Nd:YAG is applied to the areas of myocardium from which that form of VT originates until it disappears and is no longer inducible. Next attempts are made to induce other forms of VT and when successful, mapping and lasing repeated until finally VT is no longer inducible. Fifty-one patients were operated on and have been followed for at least 1 year. Operative mortality in 12 patients with preoperative ejection fractions less than 20% was 41%; in 39 patients with ejection fractions greater than 20% operative mortality was 8%. Eighty-eight percent of the 43 operative survivors are free of recurrent sustained VT at 1 year. There have been no arrhythmic mortalities. In a group of 30 patients evaluated for epicardial VT, 9 of 14 patients with inferior infarcts without left ventricular aneurysms had at least one form of epicardial VT. Nd:YAG laser photocoagulation of myocardial VT using a sequential approach is a viable method that permits an ongoing study of this entity. Operative mortality remains high in patients with diffusely poor left ventricular function. Epicardial VT is frequent in patients with inferior infarcts and may account for inferior results in these patients when conventional endocardial approaches are used alone.


Transcoronary chemical ablation of arrhythmias. Chemical or electrical ablation of an arrhythmogenic ventricular area and the atrioventricular (AV) node is still an experimental technique. After we introduced alcohol ablation in the clinical situation we conducted this study to develop the catheter technique for delivering alcohol in patients with incessant ventricular tachycardia after myocardial infarction and patients with atrial fibrillation and flutter with uncontrollable ventricular rates. In patients with incessant ventricular tachycardia, the coronary artery supplying blood to the site of origin of the tachycardia could be identified by the combined information from coronary and left ventricular angiography and from programmed electrical stimulation, including endocardial mapping and pace mapping. In the 12 patients with incessant ventricular tachycardia we selected, the coronary artery supplying blood to the site of origin of the tachycardia could be identified and catheterized in ten patients. Ethanol ablation was successful in all of them. With a follow-up from 2 to 44 months, seven of the ten treated patients are still alive and six remain free of tachycardia. In patients with atrial fibrillation or flutter and uncontrollable ventricular rates, the AV artery could be catheterized and ethanol injected in 13 of the 19 patients. Complete block was produced in ten patients and AV conduction was sufficiently modified to control symptoms in three patients. Long-term results with ethanol ablation have remained excellent in this setting. Chemical ablation is a technique that may be of enormous value and even lifesaving for patients with an incessant form of tachycardia not responding to any form of medical therapy. Transcoronary ablation of AV conduction should be considered in patients with a right dominant coronary circulation in whom radiofrequency ablation has failed.


Radiofrequency catheter ablation of accessory pathways. One hundred five patients with an accessory atrioventricular pathway underwent catheter ablation of the pathway using radiofrequency current. There were 79 accessory pathways located on the left and 32 on the right side of the heart. In patients with right-sided pathways ablation was attempted via a catheter positioned at the atrial aspect of the tricuspid annulus. In patients with a left-sided free-wall accessory pathway a novel approach was utilized in which the ablation catheter was positioned in the left ventricle directly below the mitral annulus. Accessory pathway conduction was permanently abolished in 93 patients (89%). Failures were mainly due to inadequate catheters used initially. It is concluded that catheter ablation of accessory atrioventricular pathways using radiofrequency current is an effective and safe therapeutic modality for patients with symptomatic tachyarrhythmias mediated by these pathways.


Behavioral states and sudden cardiac death. Remarkable progress has been made both experimentally and clinically in defining the influence of behavioral states on susceptibility to life-threatening arrhythmias. Biological models have been developed to emulate anger and fear and have permitted detailed study of the intermediary mechanisms involved in stress-induced ischemia and ventricular fibrillation. The studies highlight the importance of adrenergic factors and the pathological significance of the poststress state. Clinically, the role of daily stresses in inducing silent myocardial ischemia and arrhythmias has been extensively characterized, and standardized behavioral stress tests have become available. Certain sleep states have been found to provoke ischemic episodes and arrhythmias. In particular, phasic rapid eye movement (REM) sleep has been shown both in animals and humans to conduce to perfusion abnormalities and propensity to fibrillation. Episodic surges in sympathetic nervous system activity appear to be the underlying basis. These conceptual and practical advances illustrate the promise of behavioral cardiology in the diagnosis and treatment of individuals at risk for sudden cardiac death.


Three decades of antiarrhythmic therapy. Over the last several decades there has been an impressive expansion in the study and management of cardiac arrhythmias. New developments in diagnostic and interventional clinical electrophysiology as well as research at the cellular tissue and whole heart levels have improved our understanding of the mechanisms of arrhythmias and have allowed the development of new and effective treatment modalities. During the 1960s (Early Decade-Enabling) the first lifesaving measures such as cardiac resuscitation, external defibrillation, and temporary pacing were introduced in the new coronary care units. Cardiac catheterization and reproducible techniques for recording of intracardiac potentials were developed. The decade of 1970 to 1980 (Middle Decade-Diagnosis) was characterized by the development of programmed stimulation for initiation and termination of arrhythmias. This represented a real revolution in clinical cardiology that led to the understanding of the nature of several tachyarrhythmias and related them to experimental mechanisms of arrhythmogenesis. In the same decade, two other diagnostic tools emerged for assessing cardiac arrhythmias and monitoring the efficacy of antiarrhythmic drug therapy: ambulatory ECG monitoring and exercise testing. In addition, the impact of antiarrhythmic drugs on ionic currents was studied and drug classifications based on these properties appeared. The decade 1980-1990 (Recent Decade-Therapy), witnessed the development of interventional electrophysiology techniques such as transcatheter ablation, and the use of cardiac surgery for the ablation of arrhythmogenic substrates. Another major advance was the design of implantable devices capable of recognizing tachyarrhythmias and treating them by programmed stimulation or defibrillation shocks. In parallel, the efficacy and safety of antiarrhythmic drugs has been reassessed and new compounds are being developed.(ABSTRACT TRUNCATED AT 250 WORDS)


Life-threatening tachyarrhythmias in athletes. The arrhythmias in competitive athletes may be classified as "benign," "paraphysiological" due to prolonged athletic training, or "pathological" due to hemodynamic effects on the athletic performance-risk-arrhythmogenic substratum. Pathological arrhythmias include life-threatening forms that are severe enough to produce symptoms (presyncope, syncope, cardiac arrest) during athletic activity. These forms are in particular rapid VT, VF, torsades de pointes, preexcited atrial fibrillation, sinus atrial and AV block. Our study population includes 766 competitive athletes, mean age 21.1 years (74 top international level), investigated with a cardioarrhythmological work-up for symptoms and for arrhythmias from 1974 to June 30, 1991. Three leading categories, represented by 16 aborted sudden death, 8 sudden death, and 7 induced VF (by EES or TAP) athletes, are described. All athletes with life-threatening arrhythmias, previously as asymptomatic or with minor symptoms had an arrhythmogenic substratum due to underlying silent cardiopathy or primary arrhythmic disorders. Athletic activity can be regarded as a trigger of electrical destabilization.


[Expression of HLA-DR antigens by colonic epithelium in ulcerative colitis]. Expression of HLA-DR antigens by colon epithelium was examined in 35 patients with ulcerative colitis (uc) among whom 21 were in relapse and 14 in remission. Control group consisted of 18 subjects with functional disorders of alimentary tract. Immunohistochemical technique using immunoperoxidase was applied. Colon epithelial cells from all control subjects were HLA-DR negative. Cells of 17 out of 21 patients with ulcerative colitis in relapse and in 4 of 14 patients in remission were HLA-DR positive. No significant correlation was observed between the number of patients with HLA-DR positive epithelium and the insensitive of inflammation estimated clinically, endoscopically and histologically. 6 patients with initially HLA-DR positive epithelium during relapse were studied for the second time and in 4 of them the negative reaction was observed after remission occurred. The aberrant expression of HLA-DR may play an important role in the initiation and/or perpetuation of inflammatory process in ulcerative colitis.


Galanin and calcitonin gene-related peptide immunoreactivity in nerves of the rat uterus: localization, colocalization, and effects on uterine contractility. Immunoreactivity to the neuropeptides galanin (GAL) and calcitonin gene-related peptide (CGRP) was examined in nerves in the rat uterus as a prelude to studying their effects on uterine contractility. With immunocytochemical techniques, GAL immunoreactivity (GAL-I) and CGRP-I were localized in myometrial nerves throughout the uterine horns and cervix, with nerves immunoreactive for CGRP being more numerous. Immunocytochemical double-labeling studies revealed GAL coexists with CGRP in a subpopulation of CGRP-I nerve fibers, i.e., GAL-I was not present in all CGRP-I nerves. Effects of these neuropeptides on uterine contractility were examined on in vitro preparations of uterine horns from diethylstilbestrol-treated rats. GAL (10(-5) to 10(-8) M) stimulated uterine contraction in a dose-related manner. CGRP had no effect on basal uterine tension, but CGRP (10(-7) M) reduced GAL-stimulated (10(-7) M) uterine contraction by 92.5%. These results demonstrate that GAL- and CGRP-I are present in, and coexist in, some uterine nerves, presumably afferent nerves. GAL and CGRP could be released from afferent fibers in an "efferent fashion" and influence uterine contractility, GAL having a contractile effect and CGRP having a relaxing effect.


Chromaticity analysis of immunostained tumor specimens. In order to evaluate the correlation between immunohistochemical and morphometric data on the same histological sections, we have developed a flexible color image analyzer (Microcomputer-Assisted Picture Processing System type II, MAPPS-II), and established an effective method to analyze the immunostained colorectal neoplasms based on the color recognition theory of human visual system. Colorectal adenomas and adenocarcinomas were stained with a monoclonal antibody C 12, which recognizes abnormal H antigen, using Avidin-Biotin method and diaminobenzidine (DAB, brown dye). Nuclei were stained with Hematoxylin (blue dye). Density and colorimetric analyses revealed two results: (A) Separation of immunostained brown area from blue nuclei was best performed by plotting the representative sample areas on a standard chromaticity diagram, which displays the hue and saturation of colors simulating color of human visual system. (B) After separation of immunostained areas, usual density analysis was useful for the assay of nuclear morphometric information. Using these programs, normal mucosa was negative for C 12, and showed low nuclear/cytoplasmic ratio (NCR). Adenoma was occasionally focally positive for C 12, and showed medium NCR. Carcinomas were C 12 positive, and showed high NCR. Our method permits nuclear counterstaining by hematoxylin instead of low contrast methyl green, which will widen the field of combined immunohistochemical and morphometric study.


Metabolic effects of galanin injections into the paraventricular nucleus of the hypothalamus. The metabolic effects of single injections of galanin into the paraventricular nucleus of the hypothalamus (PVN) were investigated in an open-circuit calorimeter. Wistar rats were tested, with no food available during the tests. In the dose range of 0.03-0.3 nmol, galanin produced a very short-latency (approximately 2 minutes) and short-lasting (approximately 15 minutes) reduction in energy expenditure. Since the same doses had no effect on respiratory quotient or locomotor activity, the metabolic effect is not secondary to changes in energy substrate utilization or locomotor activity. This antithermogenic effect complements the eating stimulatory action of PVN galanin, and together these phenomena suggest a role for galanin as an anabolic neuropeptide. The similarity of galanin's effects to those of norepinephrine, with which it coexists in PVN nerve endings, further suggests the involvement of this amine and the PVN alpha2-noradrenergic system in galanin's mechanism of action.


Galanin inhibits adenylate cyclase of rat brain membranes. The ubiquitous neuropeptide, galanin, strongly inhibits adenylate cyclase in rat brain membranes. While basal enzyme activity was not altered, galanin from 10(-11) M to 5 x 10(-7) M decreased forskolin- and VIP-stimulated adenylate cyclase with a half-maximal effect being elicited by 0.7 nM neuropeptide and a maximal 80% inhibition of the enzyme activity. The galanin fragments (2-29) and (1-15) dose-dependently inhibited the forskolin-stimulated adenylate cyclase, while the fragments (3-29) and (10-29) were found inactive. These results indicate that the regulatory action of galanin in the central nervous system involves the coupling of galanin receptors to the inhibition of the adenylate cyclase system.


NK cell activity in treated prostate cancer patients as a probe for circulating tumor cells: hormone regulatory effects in vivo. Natural killer (NK) cell activity was studied together with tumor marker serotests (PSA, PAP) and blood testosterone, estradiol, cortisol, and prolactin concentrations in treated prostate cancer patients. NK cell activity data were correlated with tumor stage (stage D0 + D1 versus stage D2) and showed statistically insignificant differences. Both tumor progression and stabilization of metastatic disease, triggered by the application of more appropriate therapy in progressive subjects, yielded low NK activity data. By contrast, normal NK activity was found during both partial remission of stage D2 tumor and stabilization of the same disease, after an initial period of tumor remission. Differences between NK activity data from the aforementioned two groups are statistically significant (P less than 0.01). In subjects examined, the application of NK activity assay to those with advanced disease reflected changes in the outcome of the treatment more closely than it did routine tumor marker assessment. The activity of NK cells seems unaffected by changes in basal blood estradiol, cortisol, testosterone, and prolactin concentrations that occur during therapy with pharmacological agents (estradiol, cyproterone acetate, diethylstilbestrol, and flutamide) and during surgical castration. The reported NK activity recordings in treated prostate cancer patients might be indicative of the presence of tumor cells in the circulation. If this holds true, the measurement of NK activity would appear to furnish urological oncology with a new tool for early, rapid recognition of progressive metastatic tumors.


Bovine pancreatic trypsin inhibitor and homologous polypeptide inhibitors in nephron cells. Bovine pancreatic trypsin inhibitor (BPTI, aprotinin) is a fifty-eight amino acid polypeptide, which is present together with related molecular isoforms in various bovine organs. In the present study these protease inhibitors were isolated from bovine kidney by affinity chromatography on immobilized trypsin and a subsequent FPLC step. Due to their electrophoretic, structural, and inhibitory properties, the inhibitors were strictly similar to the polypeptides identified previously in other bovine organs. Immunohistochemical experiments showed a widespread localization of these polypeptides in nephron epithelial cells (proximal and distal tubules, loop of Henle, collecting tubules).


Regulation of prostatic carcinoma cell proliferation and secretory activity by extracellular matrix and stromal secretions. Previous studies from our laboratory have shown that reconstituted basement membrane and stromal secretory products are important regulators of benign prostatic epithelial cell growth and differentiation. In the present study we evaluated the impact of extracellular matrix (ECM) and soluble stromal secretory products on the proliferation and secretory activity of the androgen-responsive prostatic carcinoma cell line LNCaP. In these studies, dihydrotestosterone (DHT) was a potent mitogen for LNCaP cells cultured on plastic or on type I collagen. The growth response to DHT was greatly attenuated when LNCaP cells were grown on prostatic stromal ECM. Cells grown on stromal ECM also exhibited clustered morphology compared to the monolayer growth observed on plastic and secreted elevated levels of prostate specific antigen (PSA) and prostatic acid phosphatase (PAP). These findings indicate that cultivation of LNCaP on stromal ECM will promote the expression of differentiated functions. In additional studies, stromal cell conditioned medium (SCM) significantly increased PSA/PAP secretion by LNCaP cells in the presence of 10 nM DHT. The enhancement of DHT-induced PSA/PAP secretion by SCM was most pronounced when LNCaP cells were grown on stromal ECM. SCM did not significantly alter LNCaP proliferation. These studies indicate that prostatic stromal ECM and soluble secretory products will promote differentiated function in cultured LNCaP cells. In addition, we show that DHT can act as either a growth or differentiation-promoting stimulus depending on the presence of stromal factors.


Prostate-specific antigen: establishment of the reference range for the clinically normal prostate gland and the effect of digital rectal examination, ejaculation, and time on serum concentrations. This study investigated the serum prostate-specific antigen concentration in 100 healthy men (mean age, 26.3 years; range, 20-29 years) with a clinically normal prostate gland. The effect of digital rectal examination and ejaculation on the serum concentration, and the variability of the serum concentration over 1-week and 1-month periods were examined. In the 100 subjects, the serum prostate-specific antigen concentration ranged from less than 0.1-2.6 ng/ml. The mean, median, and mode were 0.68 ng/ml, 0.6 ng/ml, and 0.4 ng/ml, respectively. The 97.5th percentile value was 2.1 ng/ml. The mean and median changes in the serum concentration after digital rectal examination were -0.013 +/- 0.11 ng/ml and 0.0 ng/ml, respectively (P = 0.59 compared with control group). The mean change after ejaculation was 0.05 +/- 0.12 ng/ml, and the median change was 0.0 ng/ml (P = 0.14 compared with control group). Diurnal variation showed minimal change in 16 patients over a 1-week period. The mean change (p.m. value-a.m. value) was 0.003 ng/ml (range, -0.2-0.06 ng/ml). In addition, the serum concentration showed minimal intrapatient variability in 20 patients throughout a 1-month period; the average coefficient of variation (standard deviation/mean) in these subjects was 16.5% (range, 6.4-45.2%). These results indicate that the range in the serum concentration of prostate-specific antigen for healthy men with a clinically normal prostate gland is significantly lower (0.0-2.6 ng/ml) than the currently employed range (0.0-4.0 ng/ml; Tandem-R PSA assay); in addition, digital rectal examination and ejaculation have no significant effect on the serum concentration. Finally, the time of day has little effect, and the variability in the serum concentration of prostate-specific antigen over a 1-week and 1-month interval is minimal.


Possible existence of a new tachykinin receptor subtype in the guinea pig ileum. The guinea pig ileum possesses NK-1 and NK-3 tachykinin receptors. As expected, [Pro9]SP and senktide, which are selective agonists of NK-1 and NK-3 receptors, respectively, were found to be highly potent in contracting the guinea pig ileum. Surprisingly, similar observations were made with septide, SP-O-CH3, [Apa9-10]SP, or [Pro9,10]SP although, in contrast to [Pro9]SP, these four peptides showed a low affinity for 3H-[Pro9]SP-specific NK-1 binding sites on membranes from the guinea pig ileum. They were also devoid of affinity for NK-2 and NK-3 binding sites. GR 71251, a compound which has been described as a NK-1 antagonist, was more potent in inhibiting the septide- than the [Pro9]SP-evoked contracting response. Altogether, these results suggest that septide, [Apa9-10]SP, and [Pro9,10]SP exert their high contracting activity in the guinea pig ileum by acting on a new subtype of tachykinin receptors.


[Activity of selected proteinase inhibitors in patients with disorders of lipid metabolism]. The study was aimed at verification of previously found, in animals with experimentally induced atherosclerosis, the disturbances of serum proteinases inhibitors: alpha-2-antiplasmin, alpha-1-antitrypsin and alpha-2-macroglobulin. In humans with hypercholesterolemia the decrease of serum activity of alpha-2-antiplasmin was observed. In humans with hypercholesterolemia and increased serum concentration of triacylglycerols no significant changes in activity of alpha-1-antitrypsin and alpha-2-macroglobulin were found--in comparison with control subjects.


Endomyocardial biopsy approach in cases with ventricular arrhythmias. Right ventricular endomyocardial biopsies were performed in patients with ventricular tachycardia (VT: n = 20) and idiopathic premature ventricular contraction (PVC: n = 23). Active myocarditis was found in one case and postmyocarditic change in 9 cases. Significant pathology according to our definition was found in 9 out of the total of 43 cases (20.5%). The pathological features of the 9 cases were interstitial fibrosis in 5, disarrangement of muscle bundles in 6, degeneration of myocytes in one and increase in fatty tissue in 7. Increase in fatty tissue was characteristically observed in 6 out of the 20 cases with VT and it was noteworthy that the VT cases with left bundle branch block configuration showed high incidence of the fatty tissue (5/12 cases, 42%).


Mesothelial and related neoplasms in children and adolescents: a clinicopathologic and immunohistochemical analysis of eight cases. Mesothelioma is a neoplasm that occurs infrequently in childhood; only an estimated 2-5% of all cases present in the first two decades of life. The diagnosis may be perplexing because of its rarity and its pathologic similarities to other papillary or spindle cell neoplasms in the pediatric age group. We have studied eight cases of mesothelial or submesothelial-derived neoplasms of pleural (four cases) and peritoneal (four cases) origin in patients 4 to 17 years of age at diagnosis. Microscopically, six were epithelial, with papillary, tubuloglandular, and solid patterns. Two tumors were predominantly fibrous appearing, one a localized pleural fibroma and the other a diffuse pleural sarcomatoid mesothelioma. All of the tumors were immunoreactive for vimentin, and all except the pleural fibroma stained for either cytokeratin, epithelial membrane antigen, or both. None reacted with antibodies to carcinoembryonic antigen, placental alkaline phosphatase, or Leu-M1. At last follow-up, three patients were dead of tumor, three were alive and well, and two had been recently diagnosed and were undergoing treatment. These results indicate that the immunohistochemical profile delineated for mesothelioma in adults is equally applicable to mesothelial neoplasms in younger patients and is useful in establishing a diagnosis. The prognosis for malignant mesothelioma in childhood appears to be as unfavorable as the adult counterpart, with the possible exceptions of certain clinicopathologic subtypes.


Undifferentiated small cell hepatoblastoma with a unique chromosomal translocation: a case report. Cytogenetic studies of pediatric tumors have revealed a number of reproducible karyotypic abnormalities, including del(p13) found in aniridia-Wilms' tumor association, t(8;14) in Burkitt's lymphoma, and t(11;22) in Ewing's sarcoma. To date, no consistent cytogenetic abnormality has been reported in association with hepatoblastoma. We report the case of a 7-month-old male infant with the undifferentiated small cell variant of hepatoblastoma. Immunohistochemistry revealed reactivity with antibodies to cytokeratin and vimentin throughout the tumor. Alpha-fetoprotein, neuron-specific enolase, and S100 stains were negative. Chromosomal analysis of metaphase cells from a culture of tumor tissue revealed a translocation of most of the long arm of chromosome 22 to the distal long arm of chromosome 10.


Conjunctival penetration of insulin and peptide drugs in the albino rabbit. An in vitro model was used to evaluate the conjunctival penetration of three peptides, [D-ala2]metenkephalinamide (YAGFM, MW 647), substance P (MW 1348), and insulin (MW 5778), in comparison with two nonpeptides, atenolol (MW 266) and timolol (MW 433). All three peptides were hydrolyzed to varying extents during penetration across the conjunctiva. The permeability coefficient for intact YAGFM and insulin was 4.5 +/- 0.3 and 4.6 +/- 0.7 microns sec-1, respectively. These values were about two to five times lower than those for atenolol and timolol. No permeability coefficient could be calculated for substance P, since its transconjunctival flux never reached steady state. The conjunctival penetration of YAGFM and insulin was improved by about two and three times, respectively, with the addition of 1% Na glycocholate. Increasing the Na glycocholate concentration was more effective than changing the type of bile salt in improving the conjunctival penetration of insulin. The maximum factor of improvement was 12, as the Na glycocholate concentration was raised to 4%. The way in which Na deoxycholate, glycocholate, and taurocholate affected the conjunctival penetration of atenolol, timolol, and insulin suggests that these three bile salts improved mainly the transcellular penetration of the compounds studied.


Anti-AIDS drug development: challenges and strategies. A myriad of chemical derivatives has been shown to inhibit in vitro replication of the AIDS virus at concentrations that are nontoxic to the host cells. The majority of these agents acts by either (i) inhibiting enzymes such as reverse transcriptase (RT), protease, or glucosidase, (ii) arresting expression of genes or gene products, or (iii) inhibiting viral processes such as giant cell (syncytia) formation or viral binding to the target cell. The nucleoside RT inhibitors are the most widely studied agents at both the preclinical and the clinical levels. Their inability to cure AIDS has stimulated the discovery of several novel nonnucleoside RT inhibitors, possessing varied structures and demonstrating activity at nanomolar concentrations. These agents demonstrate a unique mode of binding to RT and show a high specificity for HIV-1. Protease inhibitors, soluble CD4 derivatives, oligonucleotides, and many anionic derivatives also demonstrate potent anti-HIV-1 activities. These derivatives possess mechanisms of action different to the nucleosides and exhibit selectivity as exemplified by their high in vitro therapeutic indices. This article discusses the structural parameters that govern activity in these agents, the pros and cons regarding the development of these compounds as putative anti-AIDS agents, and the future promise of searching for newer agents directed at novel targets to inhibit the AIDS virus.


Antisense c-myc oligodeoxyribonucleotide cellular uptake. Antisense oligonucleotides have therapeutic potential as inhibitors of gene expression. However, the mechanism by which an intact oligonucleotide reaches the intracellular site of action is unknown. In this study, we use an oligodeoxyribonucleotide 21-mer complementary to the translation initiation codon of the c-myc protooncogene to study the mechanism of oligonucleotide uptake and internalization into Rauscher Red 5-1.5 cells. We find trypsin-sensitive and trypsin-insensitive surface binding, in addition to internalization. Uptake is partially energy dependent and inhibited by charged molecules, including DNA, ATP, a random sequence oligonucleotide, and dextran sulfate. Uptake does not appear to occur via a traditional receptor-mediated uptake pathway because chloroquine, monensin, and phenylarsine oxide pretreatment does not significantly decrease internalization. An anion channel inhibitor, SITS, and the salts, NaCl, Na2SO4, and NH4Cl, significantly decrease oligonucleotide uptake. Whether uptake occurs via a channel or a novel uptake mechanism is still unknown. A model is proposed which reasonably simulates the experimental data.