Unsuccessful AV Nodal Ablation in Atrial Fibrillation: An Alternative Method to Achieve Complete Heart Block

We report the case of an elderly patient who presented with poorly tolerated episodes of atrial arrhythmia refractory to medical treatment. AV node ablation was identified as the only alternative expected to be efficacious for symptom relief. However, this usually simple intervention failed. The goal of creating a complete AV block was finally achieved through ablation of the anterior fascicle of the His bundle, which represented the only pathway for residual conduction in this patient.

Severity of systemic lupus erythematosus with diffuse proliferative glomerulonephritis and the ineffectiveness of standard pulse intravenous cyclophosphamide therapy in Jamaican patients

The majority of patients seen at the renal clinic of the University Hospital of the West Indies (UHWI) are of African descent. The case notes of patients with systemic lupus erythematosus (SLE) with class 4 nephritis and who were given standard pulse intravenous cyclophosphamide therapy during the period 1990-2000 were retrospectively reviewed. Primary outcomes were doubling of serum creatinine and development of end stage renal disease (ESRD). Secondary outcomes were return of proteinuria to normal and renal remission. A total of 117 patients had a renal biopsy for SLE nephritis at the UHWI between 1990 and 2000. Of the patients, 34 (29%) had diffuse proliferative glomerulonephritis (WHO class 4), of which 29 were reviewed. Twenty-two patients of 24 in whom it was measured (92%) had significant proteinuria at presentation. The 24-hour proteinuria was measured at final review in 16 patients and in 10 patients it went into complete remission. At the beginning of therapy, 24 patients (83%) had renal impairment. Of the 18 who had final creatinine values, the renal function returned to normal in eight patients (44%) and an additional six patients showed a significant improvement in renal function at final review. Six patients developed end stage renal disease (ESRD). The risk (95% confidence interval) of developing ESRD at one year was 16.2% (CI, 6.4-37.6) and at two years was 23.2% (CI, 10.0-48.5). There were three deaths, two from sepsis and one from heart failure. The one-year mortality (95% CI) was 8% (CI, 2.0-28.5), the two-year mortality was 15.6% (CI, 4.9-43.5) and the five-year mortality was also 15.6% (CI, 4.9-43.5). Intravenous pulse cyclophosphamide for Jamaican patients with SLE and diffuse proliferative glomerulonephritis is an ineffective form of treatment.

Structure and dynamics of polymer-grafted clay suspensions

The structure and dynamics of polymer-grafted two-dimensional silicate layers in solution were investigated. The geometry of the individual silicate layers was examined by looking at both polarized and depolarized light scattering from dilute solutions, while higher-concentration systems were used to study the interaction and dynamics of polymer-grafted silicate layers in suspension. The form factor for an oblate ellipsoid was used to fit the polarized intensity profile, and values of a approximately 80 nm and b approximately 380 nm for the semi-axes were obtained. The 80 nm value compares reasonably with the dimensions of the polymer brushes grafted on the surface of the silicate layers. The modulus of the grafted silicate in solution, as determined by Brillouin scattering, is of the order of 10 GPa. The cooperative diffusion mechanism, typical of interacting polymer chains, is suppressed due to the high polymer osmotic pressure. The osmotic pressure is also responsible for the weak interpenetration of the densely grafted polymer chains on the surface of the silicate layers. The scattering data indicates that the polymer-grafted nanoparticles move via collective diffusion and experience significant decrease in mobility above their overlap concentration.

No Panacea for Drainage after Percutaneous Nephrolithotomy

BACKGROUND AND PURPOSE

The optimal postoperative drainage system for patients undergoing percutaneous nephrolithotomy (PCNL) has not yet been determined. Each of the different tubes available has theoretical advantages and disadvantages. The objective of this study was to determine if any one system of post-PCNL drainage has any significant advantage over the others.

PATIENTS AND METHODS

Sixty patients were randomized to either a 24F Re-entry tube (Group 1), an 8F pigtail catheter (Group 2), or a double-J stent (Group 3) (N = 20 for all groups). The double-J stent patients also had an 18F Councill catheter as a nephrostomy tube, which was removed on the morning of postoperative day 1. The three groups were well-matched for age, stone size, operative time, and mean number of percutaneous tracts (P > 0.05 for all). Data collected included intraoperative findings, postoperative analog pain scores and narcotic usage, presence of extravasation on postoperative nephrostogram, presence of perinephric fluid on postoperative ultrasound scans, length of stay, and whether leakage from the nephrostomy site persisted more than 48 hours after tube removal.

RESULTS

There were no statistically significant differences among the three groups in terms of change in hematocrit or number of patients requiring blood transfusion; in the incidence of tube blockage, extravasation, or presence of perinephritic fluid; or in complication rates, length of hospital stay, or persistent leakage after tube removal. There was a strong trend to less postoperative leakage with the 8F pigtail than the Reentry tube (P = 0.05). Postoperative analog pain scores and narcotic usage were equivalent for all three groups. Patients Groups 1 and 2 were free of all tubes sooner than patients in Group 3 (P < 0.001).

CONCLUSIONS

This study did not demonstrate an overwhelming advantage of any one drainage system over the others. All three systems were equally tolerated by patients. There may be less chance of prolonged nephrostomy-site leakage with an 8F pigtail catheter.

Bilateral epididymal metastases from primary adenocarcinoma of the prostate

A 65-year-old man diagnosed with adenocarcinoma of the prostate gland opted for hormonal manipulation and had bilateral orchiectomy. Histological evaluation showed tumour deposits in both epididymides. Despite the relatively common occurrence of adenocarcinoma of the prostate, epididymal metastasis is a rare occurrence. This case highlights the need for proper evaluation of the testes and para-testicular structures so that accurate staging of these tumours can be made.

A case of pulmonary lymphangioleiomyomatosis

A case of pulmonary lymphangioleiomyomatosis (PLAM) occurring in a 48-year-old Jamaican female is presented. The clinical, radiological, and pathological findings are typical of this rare condition, and serve to emphasize the need for a high index of suspicion in order to make the diagnosis and commence therapy early in the course of the disease. The outlook for patients with PLAM continues to be poor.

Type 2 diabetes mellitus and thyrotoxicosis presenting concurrently

The symptoms of thyrotoxicosis and diabetes mellitus can be quite similar, and in patients presenting with diabetes, thyrotoxicosis could be missed unless specifically tested for. There are few reports of the two conditions presenting at the same time. We report on two such cases. In a patient who is diagnosed as having both conditions concurrently, an oral glucose tolerance test should be repeated after successful treatment of thyrotoxicosis before a diagnosis of diabetes mellitus is made.

Penile involvement in Henoch-Schonlein purpura

The authors report the case of a four-year-old boy who, having been diagnosed as having uncomplicated Henoch-Schonlein purpura, returned five days later with a new crop of lesions and sudden onset of engorgement and oedema of the penis. Testicular and scrotal involvement has been well documented in Henoch-Schonlein purpura but involvement of the penis alone has not been widely reported.

Action of MDMA (ecstasy) and its metabolites on arginine vasopressin release

3,4-Methylenedioxymethamphetamine (MDMA) has been reported to cause hyponatraemia, which appears to result from inappropriate secretion of the antidiuretic hormone arginine vasopressin (AVP). After administration of a low dose of (R,S)-MDMA (40 mg) to eight healthy drug-free male volunteers, concentrations of AVP in plasma increased significantly at 1, 2, and 4 hours. Although no relation between plasma MDMA and AVP was found on an examination of the entire data set over the 24-hour study period, a statistically significant negative correlation was observed at 1 hour. As this occurred at a time when both AVP and MDMA concentrations were rising, it was postulated that a metabolite, or metabolites, could primarily be responsible for the increase in AVP. To test this hypothesis we examined the effect of MDMA and five of its metabolites, in the dose range 0.1-1,000 nM, on AVP release from the isolated rat hypothalamus. All compounds tested were found to increase AVP release (using 10 nM and 1,000 nM concentrations), with 4-hydroxy-3-methoxymethamphetamine (HMMA), the major metabolite of MDMA, being the most potent, and 3,4-dihydroxymethamphetamine (DHMA) the least potent. Each compound (1,000 nM), with the exception of DHMA, also enhanced the response to 40-mM potassium stimulation. Our findings confirm that metabolites of MDMA, in addition to the parent drug, contribute to AVP secretion in vitro. Further work will demonstrate whether this is also true in vivo.

Association of surgical specialty and processes of care with patient outcomes for carotid endarterectomy

BACKGROUND AND PURPOSE

Because there is considerable variation in practice patterns and outcomes for carotid endarterectomy (CE), there is a need to study the processes of care that are associated with adverse outcomes. The purpose of this study was to examine the impact of processes of care and surgical specialty on adverse outcomes for CE.

METHODS

A retrospective cohort study based on a voluntary CE registry containing 3644 patients undergoing CE between April 1, 1997, and March 31, 1999, in New York hospitals was used in the study. A multivariable statistical model was used to identify significant independent patient risk factors and to examine the association of processes of care and surgical specialty with outcomes after adjustment for differences in patient risk factors.

RESULTS

The overall adverse outcome (in-hospital death or stroke) rate was 1.84%. After adjustment for differences in 7 patient risk factors that were significantly related to adverse outcomes, the use of >/=1 specific processes of care (eversion endarterectomy, protamine, or shunts) was found to be associated with lower odds of an adverse outcome relative to patients undergoing CE without the processes (OR=0.42, P=0.006). Similarly, patients undergoing surgery performed by vascular surgeons had lower odds of experiencing an adverse outcome (OR=0.36, P=0.009). Processes of care and surgical specialty were highly correlated with one another.

CONCLUSIONS

Processes of care and surgical specialty are significant interrelated determinants of adverse outcome for CE.

Cholelithiasis in a child--an unusual presentation of Wilson's disease

A nine year old mentally retarded girl with moderate splenomegaly and ascites presented with chronic cholelithiasis. The presence of Kayser-Fleischer rings and low serum ceruloplasmin level confirmed the diagnosis of Wilson's disease. Cirrhosis of liver and recurrent episodes of hemolysis--these two common complications of Wilson's disease make an ideal setting for gall stone formation. Only three such cases have been reported worldwide and ours is the first case report from India. We suggest that cholelithiasis and splenomegaly in a child without evidence of congenital hemolytic disease should be taken as a suspect of Wilson's disease.

Widespread bone disease in acute myeloid leukaemia

We describe a 11-year-old boy with acute myeloid leukaemia who presented with widespread bone disease. Spine X-rays revealed multiple crush fractures and there were multiple hot spots on the bone scan. The bone-mineral density was markedly reduced but there was no hypercalcaemia or hypercalcuria. Bone marrow aspirate revealed 98% blast cells and a balanced translocation between chromosomes 10 and 17 in seven of nine metaphases. Plasma interleukin-6 level before chemotherapy was high at 53 pg/ml. We postulate that the mechanism for bony destruction in this case was similar to that in the adult disease myeloma.

POU genes in metazoans: homologs in sea anemones, snails, and earthworms

Previously undescribed POU genes were detected in several invertebrate phyla using redundant primers in a polymerase chain reaction (PCR) that targeted highly conserved sequences encoding known POU-domains. A class IV gene and a gene tentatively assigned to class VI were identified in sea anemones (Condylactis), two distinct class III genes were identified in snails (Biomphalaria), and a single class IV gene was identified in earthworms (Lumbricus). The identification of POU genes in cnidarians, mollusks, and annelids completes a survey of the major metozoan phyla. As POU genes exist in all of these organisms, they appear to be a fundamental characteristic of the metazoan lineage, and may have played a major role in the diversification of these organisms.

Placental lesions associated with abnormal growth in twins

Abnormal growth in one or both twins may contribute to the increased morbidity and mortality observed in twin gestation. Our objective in this retrospective study of all twin pregnancies delivered at our hospital (n = 240) over a 2-year period was to study the relationship between placental lesions and abnormal growth. Standardized placental examinations were performed in 192 cases (80%), which constituted the study population. Two growth abnormalities were studied: discordant growth as defined by > 15% difference in birth weight and small-for-gestational-age (SGA) birth as defined by birth weight less-than the 10th percentile for gestational age. The majority of twin pregnancies with either discordant growth (41/57 cases) or SGA birth (26/35 cases) had dichorionic placentas. In monochorionic placentas studied by injection there was no significant relationship between vascular anastomoses and discordant growth. Placental weight for small discordant and SGA twins was equivalent or increased relative to infant weight, a pattern not suggestive of maternal vascular underperfusion. Eight lesions, five considered to represent chronic placental disease and three considered to represent intrauterine adaptation, were studied as possible predictors of abnormal growth. The overall prevalence of these lesions in twin placentas was less than that seen in singleton births. Concordance between twin placentas for most lesions was higher than would be expected, based on their prevalence in singleton placentas. Two lesions were associated with discordant growth in both univariate and multivariate analyses: peripheral cord insertion (OR 3.6, 95% CI 1.7-7.6) and avascular villi (AV; OR 3.2, 95% CI 1.0-10.3). Three placental lesions were associated with SGA infants at the univariate level: peripheral cord insertion, avascular villi, and maternal vascular underperfusion. Only peripheral cord insertion (OR 9.8, 95% CI 4.1-23.4) and AV (OR 3.7, CI 1.0-13.7) were significant in the multivariate analysis. The relative increase in peripheral cord insertion and AV with abnormal growth was observed for both monochorionic and dichorionic placentas. Subgroups of discordant infants with and without SGA were both associated with peripheral cord insertion while only those with SGA had an increase in AV. Both peripheral cord insertion and AV were increased in the subgroup with SGA but no discordancy. In summary, two placental lesions, peripheral cord insertion indicating a spatially limited intrauterine compartment and AV indicating occlusion of fetal vessels in the placenta, were associated with abnormal growth in twins.

Perinatal correlates and neonatal outcomes of small for gestational age infants born at term gestation

OBJECTIVE

We sought to examine the current perinatal correlates and neonatal morbidity associated with intrauterine growth failure among neonates born at term gestation.

STUDY DESIGN

We compared 372 small for gestational age (SGA, birth weight <10th percentile) infants born at term gestation to 372 appropriate for gestational age controls (AGA, birth weight 10th to 90th percentile) matched by sex, race, and gestational age within 2 weeks.

RESULTS

Compared with AGA controls, significant (P < .05) maternal risk factors for SGA status included single marital status (59% versus 53%), lower prepregnancy weight (144 +/- 41 lbs versus 153 +/- 40 lbs), lower weight gain during pregnancy (29 +/- 15 lbs versus 33 +/- 15 lbs), smoking (25% versus 17%), hypertension (14% versus 7%), and multiple gestation (9% versus 2%). Mothers of SGA infants were more likely to undergo multiple (>or=3) antenatal ultrasound evaluations (19% versus 7%), biophysical profile monitoring (11% versus 4%), and oxytocin delivery induction (28% versus 16%) (P < .05). Pediatrician attendance was more common among SGA deliveries (50% versus 37%, P < .05). SGA infants had significantly higher rates of hypothermia (18% versus 6%) and symptomatic hypoglycemia (5% versus 1%). These neonatal problems remained significant even when medical or pathologic causes of intrauterine growth failure, including pregnancy hypertension, multiple gestation, and congenital malformations, were excluded.

CONCLUSION

Despite higher rates of pregnancy complications among mothers of SGA infants, the rates of neonatal adverse outcomes are low. However, SGA infants remain at risk for hypothermia and hypoglycemia and require careful neonatal surveillance.

Effect of gestational zinc deficiency on pregnancy outcomes: summary of observation studies and zinc supplementation trials

The lack of a valid indicator precludes a true estimate of zinc deficiency in pregnancy in various populations. However, it is possible that mild to moderate deficiency (as assessed by available indicators) may be common in the developing world. Animal experiments indicate that zinc deficiency can result in adverse maternal and fetal consequences. Human data, particularly from prenatal zinc supplementation trials, has failed to document a consistent maternal or infant benefit on evaluated outcome measures including pregnancy induced hypertension, preterm/post-term labour, premature rupture of membranes, maternal infection, postpartum haemorrhage, perinatal mortality, congenital malformations and fetal growth and gestation. Preliminary data suggest a beneficial effect of prenatal zinc supplementation on infants' neurobehavioural development and immune function (evaluated by diarrhoeal and ARI morbidity incidence in the first year of life). Future research should focus on these functional consequences and congenital malformations (with adequate sample sizes), and simultaneously address the safety issue, particularly in relation to micronutrient interactions. In the light of the currently available information, routine zinc supplementation can not be advocated to improve pregnancy outcome.

Evidence in Escherichia coli that N3-methyladenine lesions induced by a minor groove binding methyl sulfonate ester can be processed by both base and nucleotide excision repair

It has been previously reported that a neutral DNA equilibrium binding agent based on an N-methylpyrrolecarboxamide dipeptide (lex) and modified with an O-methyl sulfonate ester functionality (MeOSO(2)-lex) selectively affords N3-methyladenine lesions. To study the interaction of the neutral lex dipeptide with calf thymus DNA, we have prepared stable, nonmethylating sulfone analogues of MeOSO(2)-lex that are neutral and cationic. Thermodynamic studies show that both the neutral and monocationic sulfone compounds bind to DNA with K(b)'s of 10(5) in primarily entropy-driven reactions. To determine how the cytotoxic N3-methyladenine adduct generated from MeOSO(2)-lex is repaired in E. coli, MeOSO(2)-lex was tested for toxicity in wild-type E. coli and in mutant strains defective in base excision repair (tag and/or alkA glycosylases or apn endonuclease), nucleotide excision repair (uvrA), and both base and nucleotide excision repair (tag/alkA/uvrA). The results clearly demonstrate the cellular toxicity of the N3-methyladenine lesion, and the protective role of base excision glycosylase proteins. A novel finding is that in the absence of functional base excision glycosylases, nucleotide excision repair can also protect cells from this cytotoxic minor groove lesion. Interaction between base and nucleotide excision repair systems is also seen in the protection of cells treated with cis-diamminedichloroplatinum(II) but not with anti-(+/-)-r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene.

Multiple sources initiating atrial fibrillation from a single pulmonary vein identified by a circumferential catheter

The pulmonary veins are the predominant source of ectopic activity initiating AF. The reproducibility of intrapulmonary vein activation during ectopic activity and/or initiation of multiple AF episodes was examined. Eighty-nine pulmonary veins (PVs) among 29 patients undergoing radiofrequency ablation of AF were studied with a 15- to 20-mm diameter, circumferential PV catheter equipped with ten electrodes and a deflectable shaft. Local electrograms were recorded simultaneously during sinus rhythm, ectopic activity, or AF onset, spontaneously or induced via the catheter left in a stable position. Fifty-four arrhythmogenic veins were identified, 39 showing isolated ectopy, and 8 displayed repetitive ectopy (in salvos). The earliest site of activation and the sequence of intra-PV activation during isolated ectopy was identical to that observed during consecutive ectopic complexes in 77% and variable in 23% during isolated ectopy. The earliest activity was sometimes limited to a single bipole. During repetitive ectopy and AF initiation, multiple sources and/or variable activation patterns were noted in 53% of instances, indicating the presence of multiple arrhythmogenic foci within the same PV. Simultaneous electrogram recordings with a circumferential PV catheter identified the presence of multiple arrhythmogenic foci within a single PV.

Differential pacing for distinguishing block from persistent conduction through an ablation line

BACKGROUND

Because complete linear conduction block is necessary to minimize the recurrence of reentrant tachycardias such as typical atrial flutter, we investigated a simple technique to recognize a persistent gap or complete linear block.

METHODS AND RESULTS

We prospectively evaluated cavotricuspid isthmus conduction in 50 patients (age 63+/-8 years, 43 men) after radiofrequency ablation. The distal and proximal bipoles of a quadripolar catheter placed close to the ablation line were successively stimulated during recording from the ablation line. We hypothesized that because the initial and terminal components of local potentials reflected activation at the ipsilateral and contralateral borders of the ablation lesion, a change to a more proximal pacing site without moving the catheter would prolong the stimulus to the initial component timing, whereas the response of the terminal component would depend on the presence of block or persistent conduction. A shortening or no change in timing of the terminal component would indicate block, whereas lengthening would indicate persistent gap conduction. The results were compared with previously described criteria for isthmus block. Ninety-two sites were assessed: 17 before and 75 after the achievement of complete isthmus block. The timing of the initial component was delayed by 19+/-9 ms, and the terminal component was advanced by 13+/-8 ms after block and delayed by 12+/-9 ms in case of persisting conduction. The sensitivity, specificity, and positive and negative predictive values for linear block were 100%, 75%, 94%, and 100%, respectively.

CONCLUSIONS

An accurate assessment of isthmus block or persistent isthmus conduction is possible with this technique of differential pacing.

Complicated appendicitis: is there a minimum intravenous antibiotic requirement? A prospective randomized trial

The proper duration of postoperative intravenous (IV) antibiotics in patients suffering complicated (perforated or gangrenous) appendicitis is debatable. Some advocate a set minimum number of IV antibiotic days whereas others discontinue IV antibiotics depending on the patient's clinical course regardless of the length of therapy. Our objective was to determine whether there are differences in morbidity and resource utilization between the two treatment methodologies. Ninety-four patients with intraoperative findings of complicated appendicitis were included. In all patients IV antibiotics were discontinued on the basis of clinical factors. However, Group 1 patients were given a minimum 5-day IV antibiotic course whereas Group 2 patients had no minimum IV antibiotic requirement. Group 1 patients received more IV antibiotics than Group 2 patients did (5.9 vs 4.3 days; P = 0.014). Infectious complications were not statistically different between the two groups (13.0% in Group 1 and 12.5% in Group 2). Average hospital stay was also not statistically different between the two groups. The data suggest that a protocol with no minimum IV antibiotic requirement in patients with complicated appendicitis does not increase morbidity. Furthermore, the protocol arm with no minimum IV antibiotic requirement led to less IV antibiotic use but did not significantly decrease hospital stay.

Definitive molecular evidence of renin-angiotensin system in human uterine decidual cells

The tissue renin-angiotensin system (RAS) has been suggested to be present in human gestational tissues, but uncertainty exists about the authenticity of this RAS, and the cellular origin of this RAS has not been defined. In the present study, we confirmed the presence of authentic renin and angiotensinogen in the prolactin-producing decidual tissue by sequencing the cDNAs generated through reverse transcription-polymerase chain reaction, confirming cDNA product sizes, and by performing Northern blot analysis of the RNA. Our comparative data demonstrate that prolactin has the highest expression in the decidual tissue, followed by renin, and that angiotensinogen has the least expression. We demonstrated with fluorescent in situ hybridization that prolactin-expressing endocrine decidual cells are the same cells that express both renin and angiotensinogen. These results have implications in regard to how the decidual RAS may be regulated and what potential role this local RAS may have in the pathogenesis of preeclampsia.

Evaluation of the WHO/UNICEF algorithm for integrated management of childhood illness between the ages of one week to two months

OBJECTIVE

To evaluate the utility of the WHO/UNICEF algoritham for integrated management of childhood illness (IMCI) between the ages of 1 week to 2 months.

DESIGN

Prospective observational.

SETTING

The Outpatient Department and Emergency Room of a medical college hospital.

METHODS

129 infants presenting to Outpatient Department (n=70) or Emergency Room (n=59) were assessed and classified as per 'IMCI' algorithm and treatment required was identified. A detailed evaluation with all relevant investigations was also done for these subjects. The final diagnoses made and therapies instituted on this basis served as 'gold standard'. The diagnostic and therapeutic agreement between 'gold standard and the 'IMCI' was computed.

RESULTS

More than one illness was present in 97(75.2%) of subjects as per 'gold standard' (mean 2.1). Subjects having any referral criteria as per 'IMCI' algorithm had a greater (p=0.002) co-existence of illnesses (mean 2.3 vs. 1.8 illnesses per child, respectively. IMCI algorithm covered majority (81-84%) of the recorded diagnoses either partly (40-41%) or fully (40-44%). The referral criteria proved quite sensitive (86-87%) in predicting hospitalization but had a lower specificity (53-58%). a total agreement with IMCI was found in 60-66% cases. The mismatch (34-40%) was more commonly of overdiagnosis (21-23%) rather than underdiagnosis (15-21%). The sensitivity of the algorithm to identify serious bacterial infection was high (96.1-96.5%) while the specificity was relatively low (51. 8-59.7%). Upper respiratory infection (URI)emerged as an important cause resulting in unnecessary referrals (13 out of 21 cases). Of the 43 cases identified as diarrhea by the algorithm, 6 had breast fed stools, which do not require any therapy. The 'IMCI' algorithm had a provision for preventive services of immunization and breastfeeding counseling (18% possibility of availing missed opportunities in both).

CONCLUSION

There is a sound scientific basis for adopting IMCI approach even in young infants as there is a need to improve the specificity of referral criteria. Two important conditions identified for possible refinement are URI and breast fed stools

Sequence of PHA synthase gene from two strains of Rhodospirillum rubrum and in vivo substrate specificity of four PHA synthases across two heterologous expression systems

A 3.0-kb genomic fragment has been isolated from Rhodospirillum rubrum (ATCC 25903) that contains an open reading frame (ORF) with strong homology to other known polyhydroxyalkanoate (PHA) synthase genes. This ORF has lower homology to the R. rubrum strain Ha PHA synthase than would be expected within the same species. We have conducted a series of heterologous expression studies evaluating the in vivo substrate specificity of PHA synthase genes from Rhodobacter sphaeroides, Ralstonia eutropha (formerly Alcaligenes eutrophus), Thiocystis violacea, and Nocardia corrallina, within the PHA-synthase-negative hosts, Ralstonia eutropha DSM541 and Pseudomonas putida GpP104. The N. corrallina PHA synthase incorporated the highest percentage of C5 monomers in the polymer when fermented in medium supplemented with 0.1% heptanoate as the sole carbon source. When the T. violacea and R. sphaeroides were expressed in the PHA-negative host DSM541, a greater percentage of C5 monomer was observed in the polymer as compared to the expression of the PHA synthase of R. eutropha, when the transconjugants were fermented in medium supplemented with 0.4% propionate. Evaluation for preference of medium-chain-length monomers demonstrated the flexibility of the N. corrallina, T. violacea, and R. eutropha synthase genes to polymerize a copolyester composed of short- and medium-chain-length monomers when the respective transconjugants were fermented in medium supplemented with 0.5% octanoate. These studies demonstrate that the PHA synthase from N. corrallina, T. violacea, and R. eutropha are able to polymerize a copolyester composed of short- and medium-chain-length monomers, while the PHA synthase from R. sphaeroides lacks this ability and only produces a short-chain-length polymer. These observations suggest that the composition of the PHA from the PHA-producing organisms does not necessarily reflect the inherent specificity of the PHA synthase.

Dual-loop intra-atrial reentry in humans

BACKGROUND

Dual-loop atrial reentrant tachycardias have not been clinically described.

METHODS AND RESULTS

Five patients (3 men, 2 women; mean age, 48+/-16 years) were studied 24+/-15 years after surgical closure of an ostium secundum atrial septal defect for drug-resistant atrial tachycardia. Complete tachycardia mapping was performed in the right atrium with multipolar catheters and a 3-dimensional electroanatomic mapping system (Biosense), followed by linear radiofrequency ablation of the narrowest part of each complete loop. Six tachycardias with a typical flutter morphology, a cycle length of 262+/-40 ms, and a superior f-wave axis (-77+/-11 degrees ) were mapped, 4 with a Biosense map including 106+/-32 points. Five figure-8 tachycardias had a counterclockwise loop around the tricuspid valve sharing a common anterior channel with a clockwise loop around the lateral atriotomy scar. One tachycardia was thought to have 2 counterclockwise loops around the same obstacles. Radiofrequency delivery in the cavotricuspid isthmus in each case transformed the tachycardia without any pause in a different morphology tachycardia with an inferior P-wave axis (50+/-42 degrees ) and nearly the same cycle length (272+/-39 ms) but with the periatriotomy loop alone. This arrhythmia required ablation of a second isthmus: between the lower end of the atriotomy and the inferior vena cava in 4 and the superior tricuspid annulus in 1. After a follow-up of 19+/-6 months, there were no recurrences.

CONCLUSIONS

Figure-8 double-loop tachycardias mimicking the ECG pattern of a common atrial flutter occur in some patients after a surgical atriotomy. Ablation of 1 loop produces a sudden transformation to a new reentrant tachycardia formed of the remaining loop that requires ablation at a second isthmus.

Reproductive and sexual health and safe motherhood in the developing world

The aim of this paper is to discuss the main hurdles and possible solutions concerning reproductive and sexual health and safe motherhood in the developing countries. In response to the changing global situation, a broader new concept of reproductive health has emerged. The Programme of Action of The International Conference on Population and Development (ICPD) emphasizes and highlights various aspects of reproductive health. No population in the world has met the goals of the ICPD. The problems are particularly acute in developing countries: between 20 and 40% of births are unwanted or wrongly timed, posing hardships for families and jeopardizing the health of a million women and children. An estimated 50 million induced abortions are performed each year, with some 20 million of these performed under unsafe conditions or by untrained providers. Almost 600,000 women die every year due to pregnancy-related causes, 99% of them in developing countries. Approximately 7.6 million infant deaths occur during the perinatal period each year. There are more than 333 million new cases of curable sexually transmitted diseases world-wide each year. Nearly 22 million people are estimated to be infected with the human immunodeficiency virus, of whom 14 million are in sub-Saharan Africa, with rapidly increasing numbers of infected persons in South and South-East Asia. When compared to the developed world, these figures are staggering because of barriers operating at different levels and preventing women from receiving care that is timely and of good quality. United efforts of obstetricians, pediatricians, sociologists, and different governmental and non-governmental organizations are required to achieve our targets.

Detection of IgM to hepatitis B core antigen in a reductant containing, chemiluminescence assay

The Abbott PRISM(R) hepatitis B core (HBc) antigen assay is an automatic in vitro competitive chemiluminescence immunoassay for the detection of total antibody to HBc (anti-HBc) antigen in human serum or plasma. The assay utilizes cysteine solution as a reducing reagent in order to maximize specificity. To help understand the effect of cysteine on detection of anti-HBc antigen, we separated and purified anti-HBc IgM and IgG from human plasma using size exclusion, protein A/G, and affinity chromatography techniques. We showed that cysteine affected the reactivity of anti-HBc IgM with recombinant HBc (rHBc) antigen but not the reactivity of anti-HBc IgG. Anti-HBc IgM treated with cysteine yielded byproducts which were reactive in the PRISM HBcore assay. Reduction-sensitive factor (RSF) - IgM fraction from serum known to be non-specific for anti-HBc activity, similarly treated with cysteine, was no longer reactive in the PRISM HBcore assay. We showed that cysteine treatment is effective against non-specific IgM in human blood. Also, the inclusion of cysteine in the PRISM HBcore assay does not compromise the detection of HBc specific antibodies.

Poly(beta-hydroxybutyrate) production in oilseed leukoplasts of brassica napus

Polyhydroxyalkanoates (PHAs) comprise a class of biodegradable polymers which offer an environmentally sustainable alternative to petroleum-based plastics. Production of PHAs in plants is attractive since current fermentation technology is prohibitively expensive. The PHA homopolymer poly(beta-hydroxybutyrate) (PHB) has previously been produced in leaves of Arabidopsis thaliana (Nawrath et al., 1994, Proc Natl Acad Sci USA 91: 12760-12764). However, Brassica napus oilseed may provide a better system for PHB production because acetyl-CoA, the substrate required in the first step of PHB biosynthesis, is prevalent during fatty acid biosynthesis. Three enzymatic activities are needed to synthesize PHB: a beta-ketothiolase, an acetoacetyl-CoA reductase and a PHB synthase. Genes from the bacterium Ralstonia eutropha encoding these enzymes were independently engineered behind the seed-specific Lesquerella fendleri oleate 12-hydroxylase promoter in a modular fashion. The gene cassettes were sequentially transferred into a single, multi-gene vector which was used to transform B. napus. Poly(beta-hydroxybutyrate) accumulated in leukoplasts to levels as high as 7.7% fresh seed weight of mature seeds. Electron-microscopy analyses indicated that leukoplasts from these plants were distorted, yet intact, and appeared to expand in response to polymer accumulation.

Design and in vivo analysis of potent non-thiol inhibitors of farnesyl protein transferase

Inhibitors of farnesyl protein transferase (FPTase) based upon a pseudotripeptide template are described that comprise an imidazole group substituted with a hydrophobic substituent. (1, 5)-Disubstitution of the imidazole group is shown to be the optimal array that leads to potent and selective inhibitors of FPTase. A variety of aryl and isoprenyl substituents are shown to afford effective inhibitors, and the mechanism by which these compounds inhibit FPTase has been investigated. The biochemical behavior of these compounds suggests that they bind to FPTase at the site usually occupied by the protein substrate. In experiments in cell culture, the methyl ester prodrugs of these inhibitors are cell permeant and potently inhibit the posttranslational modification of H-Ras protein. Additionally, these molecules revert the phenotype of ras transformed cells as evidenced by their ability to slow the growth of ras transformed cell lines in soft agar. One of the inhibitors, as its methyl prodrug, was evaluated in two in vivo models of tumor growth. The compound selectively inhibited the growth of tumors derived from H-ras transformed cells, in nude mice, and caused the regression of preexisting tumors in an H-ras transgenic animal model.

Evaluation of the WHO/UNICEF algorithm for integrated management of childhood illness between the age of two months to five years

OBJECTIVE

To evaluate the utility of the "WHO/UNICEF algorithm for integrated management of childhood illness (IMCI) between the age of 2 months to 5 years.

DESIGN

Prospective observational.

SETTING

The Outpatient Department and Emergency Room of a medical college hospital.

METHODS

203 children presenting to Outpatient Department (n=101) or Emergency Room (n=102) were assessed and classified as per 'IMCI' algorithm and treatment required was identified. A detailed evaluation with all relevant investigations was also done for these subjects. The final diagnoses made and therapies instituted on this basis served as 'gold standard'. The diagnostic and therapeutic agreements between the 'gold standard' and the IMCI and vertical (on the basis of primary presenting complaint) algorithms were computed.

RESULTS

More than one illness was present in 135 (66.5%) of subjects as per 'gold standard'. The mean (SD) numbers of morbidities as per the gold standard and IMCI- low and high malaria risks were 2.1 (1.1), 1.8 (1.0) and 2.2 (1.1), respectively. Subjects having any referral criteria as per IMCI module had a greater co-existence of illnesses (mean 2.6 vs. 1.6 illnesses per child, respectively). The referral criteria proved useful in predicting hospitalization and a combination of hospitalization and observation; their sensitivity and specificity were 81% and 69% and 74% and 85%, respectively. IMCI algorithms covered majority (92%) of the recorded illnesses. A total agreement with IMCI (malaria low risk) was found in 129 (64%) cases while in 43 (22%) cases, there was partial agreement. Corresponding figures for vertical (split IMCI) program were 93 (46%; p<0.001) and 41 (25%). The difference was primarily due to underdiagnoses (30%). Diagnostic discordance of IMCI algorithm and gold standard was evident for the cough category due to underdiagnosis of bronchial asthma and bronchiolitis and an overdiagnosis of pneumonia whereas the discordance for fever was due to an overdiagnosis of malaria. Identical results were found for broad treatment categories. The IMCI algorithm had a provision for preventive services of immunization (16.3% possibility of availing missed opportunities) and feeding advice.

CONCLUSIONS

There is a sound scientific basis for adopting the IMCI approach since: (i) co-existence of morbidities is frequent; (ii) severe illness is assessed with good sensitivity and specificity; and (iii) the IMCI algorithm is diagnostically and therapeutically superior to the vertical disease specific algorithms. The generic IMCI algorithm needs adaptation to reflect the regional morbidity profile.

Non-thiol 3-aminomethylbenzamide inhibitors of farnesyl-protein transferase

The design and syntheses of non-thiol inhibitors of farnesyl-protein transferase are described. Substitutions on an imidazolylmethyl-AMBA-methionine template gave a highly potent and cell-active inhibitor.

Relationship between DNA methylation and mutational patterns induced by a sequence selective minor groove methylating agent

Me-lex, a methyl sulfonate ester appended to a neutral N-methylpyrrolecarboxamide-based dipeptide, was synthesized to preferentially generate N3-methyladenine (3-MeA) adducts which are expected to be cytotoxic rather than mutagenic DNA lesions. In the present study, the sequence specificity for DNA alkylation by Me-lex was determined in the p53 cDNA through the conversion of the adducted sites into single strand breaks and sequencing gel analysis. In order to establish the mutagenic and lethal properties of Me-lex lesions, a yeast expression vector harboring the human wild-type p53 cDNA was treated in vitro with Me-lex, and transfected into a yeast strain containing the ADE2 gene regulated by a p53-responsive promoter. The results showed that: 1) more than 99% of the lesions induced by Me-lex are 3-MeA; 2) the co-addition of distamycin quantitatively inhibited methylation at all minor groove sites; 3) Me-lex selectively methylated A's that are in, or immediately adjacent to, the lex equilibrium binding sites; 4) all but 6 of the 33 independent mutations were base pair substitutions, the majority of which (17/33; 52%) were AT-targeted; 5) AT --> TA transversions were the predominant mutations observed (13/33; 39%); 6) 13 out of 33 (39%) independent mutations involved a single lex-binding site encompassing positions A600-602 and 9 occurred at position 602 which is a real Me-lex mutation hotspot (n = 9, p < 10(-6), Poisson's normal distribution). A hypothetical model for the interpretation of mutational events at this site is proposed. The present work is the first report on mutational properties of Me-lex. Our results suggest that 3-MeA is not only a cytotoxic but also a premutagenic lesion which exerts this unexpected property in a strict sequence-dependent manner.

Red cell distribution and the recruitment of pulmonary diffusing capacity

The distribution of red blood cells in alveolar capillaries is typically nonuniform, as shown by intravital microscopy and in alveolar tissue fixed in situ. To determine the effects of red cell distribution on pulmonary diffusive gas transport, we computed the uptake of CO across a two-dimensional geometric capillary model containing a variable number of red blood cells. Red blood cells are spaced uniformly, randomly, or clustered without overlap within the capillary. Total CO diffusing capacity (DLCO) and membrane diffusing capacity (DmCO) are calculated by a finite-element method. Results show that distribution of red blood cells at a fixed hematocrit greatly affects capillary CO uptake. At any given average capillary red cell density, the uniform distribution of red blood cells yields the highest DmCO and DLCO, whereas the clustered distribution yields the lowest values. Random nonuniform distribution of red blood cells within a single capillary segment reduces diffusive CO uptake by up to 30%. Nonuniform distribution of red blood cells among separate capillary segments can reduce diffusive CO uptake by >50%. This analysis demonstrates that pulmonary microvascular recruitment for gas exchange does not depend solely on the number of patent capillaries or the hematocrit; simple redistribution of red blood cells within capillaries can potentially account for 50% of the observed physiological recruitment of DLCO from rest to exercise.

Radiofrequency catheter ablation of drug refractory symptomatic ventricular ectopy: short- and long-term results

We performed radiofrequency catheter ablation (RFCA) in 12 consecutive patients (17-77 years) with daily, symptomatic, monomorphic ventricular ectopy (VE) (12,096 +/- 3,326 on 24-hour Holter) resistant to antiarrhythmic drugs. Nine patients had no apparent structural heart disease, 1 patient had a mild dilated cardiomyopathy, 1 patient had a treated mitral stenosis, and 1 patient had arrhythmogenic ventricular dysplasia. VE morphology was LBBB with inferior axis in 9 patients, RBBB with inferior axis in 2 patients, RBBB with superior axis in 1 patient. None of the patients had spontaneous or inducible sustained ventricular tachycardia. The VE focus was targeted with RF energy at the earliest endocardial activation site and based on a matching 12-lead ECG pace map. The VE focus was localized in the right outflow tract in 9 patients and on the left ventricle in 3 patients. RFCA was delivered with a standard 4-mm tip electrode. The ablation was initially successful in 11 patients and unsuccessful in 1 patient. All successfully ablated patients were asymptomatic and discharged without antiarrhythmic drugs. During follow-up (25 +/- 8; 17-38 months), two patients had a recurrence of symptoms, which were controlled by a previously ineffective drug. At the end of follow-up, 1,329 +/- 3198 VE were observed on Holter monitoring (P < 0.001 compared with initial values). No short- and long-term complications were observed. RFCA is a safe and effective method for treating drug-resistant symptomatic monomorphic VE in carefully selected patients. A persistent benefit without complications was obtained over a 2-year follow-up.

Red cell distribution and the recruitment of pulmonary diffusing capacity

The distribution of red blood cells in alveolar capillaries is typically nonuniform, as shown by intravital microscopy and in alveolar tissue fixed in situ. To determine the effects of red cell distribution on pulmonary diffusive gas transport, we computed the uptake of CO across a two-dimensional geometric capillary model containing a variable number of red blood cells. Red blood cells are spaced uniformly, randomly, or clustered without overlap within the capillary. Total CO diffusing capacity (DLCO) and membrane diffusing capacity (DmCO) are calculated by a finite-element method. Results show that distribution of red blood cells at a fixed hematocrit greatly affects capillary CO uptake. At any given average capillary red cell density, the uniform distribution of red blood cells yields the highest DmCO and DLCO, whereas the clustered distribution yields the lowest values. Random nonuniform distribution of red blood cells within a single capillary segment reduces diffusive CO uptake by up to 30%. Nonuniform distribution of red blood cells among separate capillary segments can reduce diffusive CO uptake by >50%. This analysis demonstrates that pulmonary microvascular recruitment for gas exchange does not depend solely on the number of patent capillaries or the hematocrit; simple redistribution of red blood cells within capillaries can potentially account for 50% of the observed physiological recruitment of DLCO from rest to exercise.