FMOD expression in whole blood aids in distinguishing between chronic lymphocytic leukemia and other leukemic lymphoproliferative disorders. A pilot study

BACKGROUND

Within the hematopoietic compartment, fibromodulin (FMOD) is almost exclusively expressed in chronic lymphocytic leukemia (CLL) lymphocytes. We set out to determine whether FMOD could be of help in diagnosing borderline lymphoproliferative disorders (LPD).

METHODS

We established 3 flow cytometry-defined groups (CLL [n = 65], borderline LPD [n = 28], broadly defined as those with CLLflow score between 35 and -20 or discordant CD43 and CLLflow, and non-CLL LPD [n = 40]). FMOD expression levels were determined by standard RT-PCR in whole-blood samples. Patients were included regardless of lymphocyte count but with tumor burden ≥40%.

RESULTS

FMOD expression levels distinguished between CLL (median 98.5, interquartile range [IQR] 37.8-195.1) and non-CLL LPD (median 0.012, IQR 0.003-0.033) with a sensitivity and specificity of 1. Most borderline LPDs were CD5/CD23/CD200-positive with no loss of B-cell antigens and negative or partial expression of CD43. 16/22 patients with available cytogenetic analysis showed trisomy 12. In 25/28 (89%) of these patients, FMOD expression levels fell between CLL and non-CLL (median 3.58, IQR 1.06-6.21).

DISCUSSION

This study could suggest that borderline LPDs may constitute a distinct group laying in the biological spectrum of chronic leukemic LPDs. Future studies will have to confirm these results with other biological data. Quantification of FMOD can potentially be of help in the diagnosis of phenotypically complex LPDs.

Free energy profiles for two ubiquitous damaging agents: methylation and hydroxylation of guanine in B-DNA

DNA methylation and hydroxylation are two ubiquitous reactions in DNA damage induction, yet insights are scarce concerning the free energy of activation within B-DNA. We resort to multiscale simulations to investigate the attack of a hydroxyl radical and of the primary diazonium onto a guanine embedded in a solvated dodecamer. Reaction free energy profiles characterize two strongly exergonic processes, yet allow unprecedented quantification of the barrier towards this damage reaction, not higher than 6 kcal mol^-1 and sometimes inexistent, and of the exergonicities. In the case of the [G(C8)-OH]˙ intermediate, we challenge the functional dependence of such simulations: recently-proposed functionals, such as M06-2X and LC-BLYP, agree on a ∼4 kcal mol^-1 barrier, whereas the hybrid GGA B3LYP functional predicts a barrier-less pathway. In the long term, multiscale approaches can help build up a unified panorama of DNA lesion induction. These results stress the importance of DFT/MM-MD simulations involving new functionals towards the sound modelling of biomolecule damage even in the ground state.

Functional consequences of transferrin receptor-2 mutations causing hereditary hemochromatosis type 3

Hereditary hemochromatosis (HH) type 3 is an autosomal recessive disorder of iron metabolism characterized by excessive iron deposition in the liver and caused by mutations in the transferrin receptor 2 (TFR2) gene. Here, we describe three new HH type 3 Spanish families with four TFR2 mutations (p.Gly792Arg, c.1606-8A>G, Gln306*, and Gln672*). The missense variation p.Gly792Arg was found in homozygosity in two adult patients of the same family, and in compound heterozygosity in an adult proband that also carries a novel intronic change (c.1606-8A>G). Two new nonsense TFR2 mutations (Gln306* and Gln672*) were detected in a pediatric case. We examine the functional consequences of two TFR2 variants (p.Gly792Arg and c.1606-8A>G) using molecular and computational methods. Cellular protein localization studies using immunofluorescence demonstrated that the plasma membrane localization of p.Gly792Arg TFR2 is impaired. Splicing studies in vitro and in vivo reveal that the c.1606-8A>G mutation leads to the creation of a new acceptor splice site and an aberrant TFR2 mRNA. The reported mutations caused HH type 3 by protein truncation, altering TFR2 membrane localization or by mRNA splicing defect, producing a nonfunctional TFR2 protein and a defective signaling transduction for hepcidin regulation. TFR2 genotyping should be considered in adult but also in pediatric cases with early-onset of iron overload.

Functional and clinical impact of novel TMPRSS6 variants in iron-refractory iron-deficiency anemia patients and genotype-phenotype studies

Iron-refractory iron-deficiency anemia (IRIDA) is a rare autosomal-recessive disorder characterized by hypochromic microcytic anemia, low transferrin saturation, and inappropriate high levels of the iron hormone hepcidin. The disease is caused by variants in the transmembrane protease serine 6 (TMPRSS6) gene that encodes the type II serine protease matriptase-2, a negative regulator of hepcidin transcription. Sequencing analysis of the TMPRSS6 gene in 21 new IRIDA patients from 16 families with different ethnic origin reveal 17 novel mutations, including the most frequent mutation in Southern Italy (p.W590R). Eight missense mutations were analyzed in vitro. All but the p.T287N variant impair matriptase-2 autoproteotylic activation, decrease the ability to cleave membrane HJV and inhibit the HJV-dependent hepcidin activation. Genotype-phenotype studies in IRIDA patients have been so far limited due to the relatively low number of described patients. Our genotype-phenotype correlation analysis demonstrates that patients carrying two nonsense mutations present a more severe anemia and microcytosis and higher hepcidin levels than the other patients. We confirm that TMPRSS6 mutations are spread along the gene and that mechanistically they fully or partially abrogate hepcidin inhibition. Genotyping IRIDA patients help in predicting IRIDA severity and may be useful for predicting response to iron treatment.

The catalytic mechanism of carboxylesterases: a computational study

The catalytic mechanism of carboxylesterases (CEs, EC 3.1.1.1) is explored by computational means. CEs hydrolyze ester, amide, and carbamate bonds found in xenobiotics and endobiotics. They can also perform transesterification, a reaction important, for instance, in cholesterol homeostasis. The catalytic mechanisms with three different substrates (ester, thioester, and amide) have been established at the M06-2X/6-311++G**//B3LYP/6-31G* level of theory. It was found that the reactions proceed through a mechanism involving four steps instead of two as is generally proposed: (i) nucleophilic attack of serine to the substrate, forming the first tetrahedral intermediate, (ii) formation of the acyl-enzyme complex concomitant with the release of the alcohol product, (iii) nucleophilic attack of a water or alcohol molecule forming the second tetrahedral intermediate, and (iv) the release of the second product of the reaction. The results agree very well with the available experimental data and show that the hydrolytic and the transesterification reactions are competitive processes when the substrate is an ester. In all the other studied substrates (thioester or amide), the hydrolytic and transesterification process are less favorable and some of them might not even take place under in vivo conditions.

Regression activity that is naturally present in vitreous becomes ineffective as patients develop proliferative diabetic retinopathy

AIMS/HYPOTHESIS

The realisation that targeting agents in the vitreous is an effective approach to treating patients with diabetic retinopathy (DR) has increased awareness that changes in the composition/bioactivity of the vitreous is a contributor to the pathogenesis of DR. The overall goal of this study was to test the hypothesis that the vitreous has regression activity, and that lysophosphatidic acid (LPA) contributes to such activity. LPA is a bioactive phospholipid present in many biological fluids, and has been recently appreciated for its ability to promote regression of blood vessels.

METHODS

Vitreous-mediated regression was monitored on tubes organised from primary retinal endothelial cells or neovessels that sprouted from retinal explants. LPA was quantified radioenzymatically.

RESULTS

Bovine and human vitreous promoted regression of retinal explant vessels and of tubes organised from primary retinal endothelial cells. LPA was a substantial component of this regression activity. Comparing the regression activities of vitreous from patients with different stages of DR revealed that, as patients developed proliferative diabetic retinopathy (PDR), vitreous lost its ability to promote regression, even though the amount of LPA did not change. The underlying mechanism was a PDR-vitreous-mediated insensitivity to LPA, which could be overcome pharmacologically.

CONCLUSIONS/INTERPRETATION

Our findings suggest that a decline in the responsiveness to regression factors such as LPA, which are naturally present in the vitreous, contributes to the pathogenesis of PDR.

Novel mutations in the ferritin-L iron-responsive element that only mildly impair IRP binding cause hereditary hyperferritinaemia cataract syndrome

Background

Hereditary Hyperferritinaemia Cataract Syndrome (HHCS) is a rare autosomal dominant disease characterized by increased serum ferritin levels and early onset of bilateral cataract. The disease is caused by mutations in the Iron-Responsive Element (IRE) located in the 5^′ untranslated region of L-Ferritin (FTL) mRNA, which post-transcriptionally regulates ferritin expression.

Methods

We describe two families presenting high serum ferritin levels and juvenile cataract with novel mutations in the L-ferritin IRE. The mutations were further characterized by in vitro functional studies.

Results

We have identified two novel mutations in the IRE of L-Ferritin causing HHCS: the Badalona +36C > U and the Heidelberg +52 G > C mutation. Both mutations conferred reduced binding affinity on recombinant Iron Regulatory Proteins (IPRs) in EMSA experiments. Interestingly, the Badalona +36C > U mutation was found not only in heterozygosity, as expected for an autosomal dominant disease, but also in the homozygous state in some affected subjects. Additionally we report an update of all mutations identified so far to cause HHCS.

Conclusions

The Badalona +36C > U and Heidelberg +52 G > C mutations within the L-ferritin IRE only mildly alter the binding capacity of the Iron Regulatory Proteins but are still causative for the disease.

An overview of a regional meteorology warning system

Abstract. In this work we present a regional meteorology warning system, particularly the operational weather warning system used by the Basque Meteorology Agency (Euskalmet) for Basque Country. System considers different meteorological phenomena capable of generate warnings, and is based on combined thresholds criteria depending on particular weather event and area of territory where is applied. In this work we describe the most significant aspects related with the warning event definition and the warning bulletin. Conclusions from comparison with the former system (prior to 2009) and feedback from different users are presented.

Psychological distress across the course of care: a case study from implantable cardioverter defibrillator to cardiac transplantation evaluation

The psychological distress of cardiac patients can complicate treatment or the recovery process. This case study presents a 47-year-old male recipient of an implantable cardioverter defibrillator who experienced multiple, consecutive shocks and subsequently developed anxiety and depressive difficulties. Psychological treatment to diminish these symptoms was employed. Despite declining cardiac function, the patient made significant progress in managing this negative affect. Subsequently, he was evaluated for cardiac transplant, and this treatment progress became critical evidence of his psychosocial suitability for transplant.

Slc7a9knockout mouse is a good cystinuria model for antilithiasic pharmacological studies

Cystinuria is a hereditary disorder caused by a defect in the apical membrane transport system for cystine and dibasic amino acids in renal proximal tubules and intestine, resulting in recurrent urolithiasis. Mutations in SLC3A1 and SLC7A9 genes, that codify for rBAT/b0,+AT transporter subunits, cause type A and B cystinuria, respectively. In humans, cystinuria treatment is based on the prevention of calculi formation and its dissolution or breakage. Persistent calculi are treated with thiols [i.e., d-penicillamine (DP) and mercaptopropionylglycine (MPG)] for cystine solubilization. We have developed a new protocol with DP to validate our Slc7a9 knockout mouse model for the study of the therapeutic effect of drugs in the treatment of cystine lithiasis. We performed a 5-wk treatment of individually caged lithiasic mutant mice with a previously tested DP dose. To appraise the evolution of lithiasis throughout the treatment a noninvasive indirect method of calculi quantification was developed: calculi mass was quantified by densitometry of X-ray images from cystinuric mice before and after treatment. Urine was collected in metabolic cage experiments to quantify amino acids in DP-treated and nontreated, nonlithiasic mutant mice. We found significant differences between DP-treated and nontreated knockout mice in calculi size and in urinary cystine excretion. Histopathological analysis showed that globally nontreated mutant mice had more severe and diffuse urinary system damage than DP-treated mice. Our results validate the use of this mouse model for testing the efficacy of potential new drugs against cystinuria.

Pancreas Islet Transplantation in Patients With Type 1 Diabetes Mellitus After Kidney Transplantation

Diabetic patients with end-stage renal disease have a high mortality rate. A combined kidney-pancreas transplant is associated with greater life expectancy. Pancreas islet transplantation is an alternative involving a lower degree of morbidity. We present two patients, of 41 and 37 years of age, with a long history of diabetes mellitus (C-peptide negative), both with a previous kidney transplant, who had been treated with 22 and 28 U of insulin/d, respectively. Both patients had frequent episodes of unawareness hypoglycemia. Pancreatic islets were infused to a total of 7809 and 19,180 IE/kg, respectively. Basal posttransplant C peptide levels were 2.9 and 1.3 ng/mL. After the implant, one patient required occasional doses of insulin, and the other patient more than 50% reduced dose. After the first implant neither patient had any episodes of unawareness hypoglycemia. HbA1c at 4 months were 6.2% and 6.9%. There were no transplant-related complications.

Doxorubicin in combination with fluorouracil and cyclophosphamide (i.v. FAC regimen, day 1, 21) versus methotrexate in combination with fluorouracil and cyclophosphamide (i.v. CMF regimen, day 1, 21) as adjuvant chemotherapy for operable breast cancer: a study by the GEICAM group

BACKGROUND

The purpose of this study was to determine the relative efficacy of doxorubicin versus methotrexate in combination with intravenous cyclophosphamide and 5-fluorouracil (FAC versus CMF) as adjuvant chemotherapy for operable breast cancer.

PATIENTS AND METHODS

Over a 4-year period, 985 women undergoing curative surgery for breast cancer (T1-3 N0-2 M0, stage I-IIIA, UICC) from nine hospitals were stratified with respect to axillary node involvement (node positive versus node negative) and randomized to receive either FAC (500/50/500/m(2)) every 3 weeks for six cycles or CMF (600/60/600/m(2)) every 3 weeks for six cycles.

RESULTS

The relative dose intensities of FAC and CMF were 87% and 85% of planned doses, respectively. Unadjusted data indicated a non-significant trend towards better results with FAC. In the prospectively formed subset of node-negative patients, disease-free survival and overall survival were statistically superior in the FAC treatment arm (P = 0.041 and 0.034, respectively), but this advantage was not seen in the subset of node-positive patients, probably because of a difference in the percentage of patients with four or more positive nodes. Adjusting data for size of treatment effect and potential interactions (number of positive nodes, tumor size, treatment center), the overall relative risk (RR) of disease recurrence and death were significantly lower with FAC treatment (RR 1.2, P = 0.03, and RR 1.3, P = 0.05, respectively). This result was mainly due to the difference observed in the node-negative patient population. Toxicity was mild: FAC induced more alopecia, emesis, mucositis and cardiotoxicity; this last was of clinical concern, but was infrequent and manageable. CMF induced more conjunctivitis and weight gain. There were no toxic deaths.

CONCLUSIONS

Doxorubicin in combination with day 1 i.v. cyclophosphamide and 5-fluorouracil is superior to methotrexate in combination with day 1 i.v. cyclophosphamide and 5-fluorouracil as adjuvant chemotherapy for operable breast cancer. A treatment effect is particularly evident in the node-negative patients. Although the clinical toxicity of FAC is greater than that of CMF, the levels were manageable and clinically acceptable.

The neurosensory tachykinins substance P and neurokinin A directly induce keratinocyte nerve growth factor

Nerve growth factor is an essential neurotrophic factor required for the growth and maintenance of cutaneous sensory nerves. In the skin, keratinocytes are a significant source of nerve growth factor; however, the regulation of cutaneous nerve growth factor production still remains to be fully understood. In this study we tested the hypothesis that neuropeptides released by cutaneous sensory nerves have the capacity to modulate directly the expression of keratinocyte nerve growth factor, which would have important implications for the maintenance and repair of nerves in the skin. In order to address this question experimentally we examined the effect of the neuropeptides, substance P and neurokinin A, on nerve growth factor expression in human keratinocytes and the murine keratinocyte PAM 212 cell line by quantitative reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and the PC-12 nerve growth factor bioassay. The results of these studies indicated that substance P and neurokinin A can directly induce nerve growth factor mRNA expression and the secretion of bioactive nerve growth factor protein in both human and murine keratinocytes. The specificity of these responses was demonstrated using neuropeptide receptor antagonists and nerve growth factor blocking antibodies. Additional studies also demonstrated a significant in vivo upregulation of keratinocyte nerve growth factor expression in murine epidermis after the topical application of the neuropeptide releasing agent capsaicin. This is the first report demonstrating the induction of cutaneous nerve growth factor by sensory nerve-derived neuropeptides such as substance P and neurokinin A. This direct effect of the neurosensory system on keratinocyte nerve growth factor production may have important consequences for the maintenance and regeneration of cutaneous nerves in normal skin and during inflammation and wound healing.

Effect of increased brain GABA concentrations on breathing in unanesthetized newborn rabbits

Evidence suggests that gamma-aminobutyric acid (GABA) is involved in control of breathing and in the hypoxia-related ventilatory depression in newborns. However, this evidence is obtained mainly from studies on anesthetized animals. Because anesthesia may interfere with the GABA system, the objectives of our study were to examine effects of GABA on ventilation (V(E)) and ventilatory response to hypoxia and to reveal effects of repeated hypoxia on GABA concentrations in unanesthetized newborns. The study was performed in rabbits in two age groups: 1-3 days old (group I) and 10-14 days old (group II). To increase brain endogenous GABA concentrations, rabbits were injected with an inhibitor of GABA transaminase, aminooxyacetic acid (AOAA; 20 mg/kg i.p.). To prevent postmortem formation of GABA, at the end of experiments the rabbits received an inhibitor of glutamic acid decarboxylase, IP-3-mercaptopropionic acid (100 mg/kg i.p.). Animals were studied in normoxia alone, or they were exposed for 15 min to 8% O(2) before and 10 and 35 min after saline or AOAA. GABA concentrations were measured in brainstem, cerebrum, and cerebellum by means of a capillary electrophoresis. In group I, AOAA had no respiratory effects. In group II, AOAA decreased V(E), tidal volume, and mean inspiratory flow in normoxia and reversed V(E) decline during hypoxia 10 min after the injection, GABA concentrations were not age dependent and the highest in the brainstem. Repeated hypoxia increased the cerebellar GABA concentrations and had no effect in group I. These results imply that in unanesthetized rabbits, GABAergic neurotransmission in the respiratory control network becomes functional by the 2nd week of life, but it does not contribute to the biphasic ventilatory response to moderate hypoxia. In contrast, GABA-evoked block of the cerebellar inhibitory input during hypoxia may be responsible for the reversal of the V(E) decline in unanesthetized newborns.

Management of pain from heel lance with lidocaine-prilocaine (EMLA) cream: is it safe and efficacious in preterm infants?

Hospitalized preterm infants undergo multiple painful heel lances. A two-phase, randomized, controlled trial was undertaken to determine the safety and efficacy of lidocaine-prilocaine 5% cream (EMLA, Astra Pharmaceuticals, L.P, Westborough, MA) for relieving pain from heel lance. One hundred twenty infants were randomly assigned to receive 0.5 g of EMLA or placebo cream for 30 minutes (Phase 1) or 60 minutes (Phase 2) before a routine heel lance. Efficacy was assessed using the Premature Infant Pain Profile (PIPP). Safety was determined by methemoglobin concentration 8 hours after EMLA application and by clinical signs of methemoglobinemia. No significant differences existed on PIPP scores between EMLA and placebo groups in Phase 1 (p < .480) or Phase 2 (p < .831). No infant had any clinical signs of methemoglobinemia. The mean methemoglobin concentration was 1.19% (.47). Approximately 10% of infants had minor skin reactions, and approximately 20% of EMLA-treated infants had blanching at the application site. The authors conclude that EMLA is safe but not efficacious for relieving pain from heel lance in preterm infants.

Endovascular stenting of an unprotected left main coronary artery stenosis in a heart transplant patient

Endoluminal revascularizaion of left main coronary artery vessels is considered to be relatively contraindicated because of a high procedural mortality and restenosis rate. This report describes the first successful case of endovascular stenting in an unprotected left main coronary artery stenosis in a heart transplant patient.

Pseudoaneurysm of the thoracic aorta presenting as purulent pericarditis and pericardial effusion

Report of a case of a mycotic pseudoaneurysm of the ascending thoracic aorta occurring in the absence of surgical or blunt trauma in a patient who presented with purulent pericarditis. Surgical pericardial drainage was required, which revealed Staphlococcal aureus. Subsequent transesophageal echocardiogram demonstrated a 4 cm x 4 cm pseudoaneurysm of the posterior wall of the aorta above the sinotubular junction. The patient refused surgical correction of the aortic pseudoaneurysm and was successfully managed with antibiotic therapy.

Periventricular haemorrhagic infarction associated with subependymal germinal matrix haemorrhage in the premature newborn. Report of two cases

Two cases of unilateral subependymal germinal matrix haemorrhage associated with homolateral periventricular haemorrhagic infarction (PVHI) are reported in two premature newborns. This association is rather rare. Indeed, PVHI occurs generally with large intraventricular haemorrhage. Diagnosis is made by brain imaging (ultrasound, MRI) scans and single photon emission computed tomography. PVHI is probably caused by obstruction of periventricular venous drainage by large intraventricular haemorrhage leading to a haemorrhagic venous infarction. From our cases, we conclude that extraventricular haemorrhage leading to a large subependymal haematoma can result in obstruction of periventricular venous drainage, subsequent PVHI and abnormal neuromotor development.

GABAergic neurotransmission in the C57BL/10 sps/sps mouse mutant: a model of absence seizures

The C57BL/10 sps/sps mouse mutant displays generalized absence seizure-like behavior. In these mice, glutamic acid decarboxylase activity is reduced in the cortex and hippocampus. Tritiated flunitrazepam binding (3H-flu) is reduced in these areas, as well as in midbrain, cerebellum, and pons-medulla. Quantitative [3H]-flunitrazepam binding autoradiography confirms these observations. GABA uptake by synaptosomes from sps/sps mice is also reduced in all the areas studied. Potassium-stimulated, Ca(2+)-dependent release of radioactivity from synaptosomes preloaded with [14C]-GABA is reduced in the hippocampus, increased in midbrain and pons-medulla, but remains unaltered in the cortex. These results suggest region-specific alterations in GABAergic neurotransmission that may be responsible for the absence-like seizures in C57BL/10 sps/sps mice.

[The relationships between cholesterol and arterial pressure in the Málaga-86 study. Something more than a casual association?]

The frequent association of this vascular risk factors implies not just a potentiation of the vascular risk, but also the need for a wider therapeutical approach on this patients not only regarding the control of the arterial hypertension but also other risk factors. After a cross-sectional study of the prevalence of various vascular risk factors in the province of Málaga (Spain), we analysed the results as for the cholesterolemia and blood pressure in normotensives and hypertensives. In the hypertensive population we observed a tendency to present a higher levels of cholesterol as well as a higher prevalence of hypercholesterolemia (p less than 0.001); on the other hand, hypercholesterolemic people versus normocholesterolemics showed similar data related to their blood pressure and prevalence of hypertension. Finally we discussed the likely etiopathogenetic interrelationships between both vascular risk factors.

Evaluation of a sustained-release theophylline product in children with asthma

The purpose of this study was to determine the dose requirements and dose interval of a sustained-release theophylline sprinkle preparation (Somophyllin-12) necessary to maintain therapeutic serum theophylline concentrations in children with asthma. Eighteen patients aged 3-7 years (subgroup 1) and 21 patients aged 8-12 years (subgroup 2), who had been on continuous theophylline therapy with Somophyllin-12, completed the study. Prior to entry into the study, each patient's dosage of Somophyllin-12 was titrated to achieve predose and peak (4-hour postdose) theophylline levels in the therapeutic range (8-20 mg/L). The patients subsequently had predose and peak serum theophylline levels determined at baseline (week 0) and at weeks 2 and 4 of the study. The majority of children maintained theophylline levels in the therapeutic range throughout the 4-week trial, and t-tests showed no significant change from baseline in mean values of peak, trough, or peak-trough theophylline differences in either patient subgroup at weeks 2 and 4. Nevertheless, some individual patients had considerable variation from baseline in peak and trough theophylline levels at follow-up visits. Dosage requirements standardized for weight were significantly higher in patients in subgroup 1 than in subgroup 2 (21.3 +/- 4.5 mg/kg per day versus 17.5 +/- 4.7 mg/kg per day; p less than 0.05). The majority of the patients required 12-hourly administration of Somophyllin-12, but seven of 39 patients required 8-hour dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of verapamil and propranolol for the initial treatment of hypertension. Racial differences in response

We compared verapamil and propranolol hydrochloride for monotherapy of hypertension. Verapamil lowered blood pressure (BP) more effectively than propranolol in black and white patients. Verapamil was equally effective in blacks and whites, whereas propranolol was more effective in whites. Heart rate was reduced by 6.0 beats per minute by verapamil, and by 13.6 beats per minute by propranolol. In blacks, verapamil lowered systolic BP 16.9 vs 8.1 mm Hg for propranolol; verapamil reduced diastolic BP 12.8 vs 8.6 mm Hg for propranolol. In whites, verapamil lowered systolic BP 19.0 vs 12.7 mm Hg for propranolol; verapamil reduced diastolic BP 16.7 vs 12.3 mm Hg for propranolol. Increases in systolic BP were observed in 22% and 3.4% of patients receiving propranolol and verapamil, respectively. The PR interval was increased from 163.5 to 174.9 ms for verapamil vs 160.3 to 164.4 ms for propranolol. Constipation (15%) and headaches (10%) were most frequent complaints for verapamil vs fatigue (18%) and dizziness (7%) for propranolol. Changes in blood biochemistry values were of small magnitude. We conclude that verapamil monotherapy is a safe and effective means of achieving BP control in patients with essential hypertension.

Isolated systolic hypertension in the elderly. A placebo-controlled, dose-response evaluation of chlorthalidone

One hundred seventy-one patients, 60 years of age or older with isolated systolic hypertension, were randomly assigned to receive chlorthalidone 12.5, 25.0, or 50.0 mg or placebo once daily for 12 weeks. The majority of the patients receiving chlorthalidone 12.5 mg achieved therapeutic success with no clinically significant biochemical changes or side effects. The 50.0-mg dose level enhanced efficacy only minimally over the 25.0-mg dose level. Drug-related side effects were significantly more prevalent in the chlorthalidone 50.0-mg group than in the placebo group. The data suggest that most elderly patients with isolated systolic hypertension, regardless of the severity, could be treated effectively and safely with chlorthalidone 12.5 mg per day.

Atypical Wenckebach periodicity simulating Mobitz II AV block

Eleven patients were studied and a total of 144 Wenckebach cycles in the AV node and 118 Wenckebach cycles in the His-Purkinje system were analysed to determine the incidence of typical and atypical Wenckebach periodicity, with particular emphasis on one variant of atypical Wenckebach that may simulate a Mobitz type II block. This pseudo-Mobitz II pattern was defined as a long Wenckebach cycle in which, at least, the last three beats of the cycle show relatively constant PR intervals (variation of no more than 0.02 s in surface leads and no more than 10 ms in His bundle electrograms) and in which the PR interval immediately following the blocked beat is shorter than the PR interval before the block by 0.04 s or more. Atypical Wenckebach cycles were found to be more common than the typical variety at both the AV node (67%) and His-Purkinje system (69%). The pseudo-Mobitz II pattern was seen in 19 per cent of atypical AV nodal Wenckebach periods and in 17 per cent of atypical His-Purkinje system Wenckebach cycles. The need to discern a 'classical' Mobitz II block from a pseudo-Mobitz II pattern, especially in the setting of an acute inferior myocardial infarction, is emphasised.

Re-entry due to manifest and concealed. His bundle ectopic systoles. Report of a case

Concealed (C) His bundle ectopic systoles (H') have been shown in man to give rise to first and second degree atrioventricular (A-V) block and to simulate nonconducted atrial premature beats (P'). This report outlines a hitherto undescribed electrophysiologic consequence of H' in a 69-year-old man with arteriosclerotic heart disease and a Wenckebach type second degree A-V block in the His-Purkinje system. During a His bundle study, H' were shown to conduct either to the atria and ventricles with varying relationships to P' and QRS, or to conduct only to the atria, simulating nonconducted P' or atrial fusion beats. Both types of H' could initiate a re-entrant arrhythmia during retrograde conduction. Of particular interest are late coupled H' that failed to conduct to the ventricles and also failed to activate the atria because of prior capture by the sinus impulse (CH'). These CH' could also initiate re-entry by conducting retrogradely to engage the subatrial re-entry circuit. Evidence is presented to suggest re-entry occurs by way of a retrograde concealed accessory pathway and antegrade conduction in the atrioventricular node.