Surfactant mediated suppression of aggregation and excited state ring puckering process in Pyrromethene 597-Application in water based dye laser

Water is being considered as an economical, safe and environmental friendly alternative solvent for dye lasers. However, the use of water in dye laser is restricted due to the formation of non-emissive aggregates of dye molecules. In the present study we have explored the possibility of the use of commercially available surfactant molecules for the water based laser of Pyrromethene 597 (PM597) dye, which has emerged as an alternative for more commonly used Rhodamine dyes in dye laser systems. Our studies show that in water, PM597 forms non-emissive aggregates which can be dissociated into monomeric dye molecules by adding common surfactants. Further, the high microviscosity in the micellar media retarded energy wasting ring puckering process in the excited state of the dye leading to the increase in its emission yield and excited state lifetime to a significant extent. It has been demonstrated that the emission yield and excited state lifetime in surfactant solution is relatively higher than in ethanol, the most commonly used organic solvent for dye lasers. Lasing action has been demonstrated in the aqueous solution of dye and lasing efficiency is found to be comparable to ethanol.

Comparative Assessment of Peritoneal Membrane Characteristics in Patients on Continuous Ambulatory Peritoneal Dialysis Using Standard Peritoneal Equilibration Test and Fast Peritoneal Equilibration Test

Background

Evaluation of peritoneal membrane permeability in patients on continuous ambulatory peritoneal dialysis (CAPD) is crucial in prescribing treatment regimens. This study evaluated peritoneal membrane characteristics in patients on CAPD using standard peritoneal equilibration test (PET) and fast PET.

Methods

A prospective observational longitudinal study included patients on CAPD with no symptoms of peritonitis for at least 4 weeks before the PET. Both, standard and fast PET were performed using 2.5% glucose-containing dialysate. The dialysate and plasma (D/P) creatinine ratios at each time point (i.e., 0 h, 2^nd h, and 4^th h) in standard and at 4^th hour only in fast PET were determined. Patients were classified according to D/P creatinine value as high, high-average, low-average, low transporter. The follow-up period was 6 months and changes in membrane characteristics were compared again to revalidate the efficacy of fast PET.

Results

A total of 50 patients between 41 and 70 years of age were enrolled. The majority had diabetic nephropathy (40%) and chronic glomerulonephritis (28%). Based on transport type, a significant positive correlation was observed between the D/P creatinine ratio of baseline standard PET I and fast PET I (r = 0.992, P ≤ 0.05) and standard PET II and fast PET II (r = 0.969, P ≤ 0.05) done after 6 months. The results of the PET and transport category after 6 months were similar in 82% cases determined by fast PET and 98% cases determined by the standard pet. There was significant agreement between both the methods of PET (K value = 0.872, P < 0.001). A significant (P ≤ 0.001) correlation was observed between standard PET I and standard PET II transport status.

Conclusion

Fast PET is a good alternative for assessing peritoneal membrane characteristics especially in the setting of less availability of resources and is a less cumbersome procedure as compared to standard PET.

Ultra-Bright Rhodamines with Sulfobutylether-β-Cyclodextrin: A Viable Supramolecular Dye Laser in Aqueous Medium

Although aqueous dye lasers are much sought after, they have been of no practical use, as laser dyes show a strong tendency for aggregation in water, thus diminishing their optical output. Contributing towards this shortcoming, we studied the noncovalent interactions of two prominent laser dyes, namely, rhodamine 6G and rhodamine B, with a water soluble macrocyclic host, sulfobutylether-β-cyclodextrin (SBE₇ βCD). Spectral changes in the absorption and fluorescence behavior of dyes in presence of the SBE₇ βCD host indicated adequate complex formation between dye and host (K∼10⁴  M^-1 ). A combination of various photophysical parameters evaluated from measurements such as Job plot, changes in the fluorescence lifetime/anisotropy values, and favorable thermodynamic parameters from isothermal titration calorimetric measurements adjudicated a 1 : 1 stoichiometric complex formation between dye and SBE₇ βCD host. Consequently, SBE₇ βCD prevents dye aggregation/adsorption and present rhodamine dyes in their monomeric forms with enhanced fluorescence yield and brightness. These vital parameters were utilized to optimize and demonstrate cost-effective supramolecular broad-band and narrow-band aqueous dye laser systems with improved lasing efficiencies (∼25 % higher for the SBE₇ βCD : RhB system and ∼10 % higher for SBE₇ βCD : Rh6G system), better beam profile, and enhanced durability compared to the respective dyes in optically matched ethanol solutions.

Delaying of cataract through intervention of Hemidesmus indicus in STZ induced diabetic rats

Hemidesmus indicus (L.) R. Br. was extensively used as hypoglycaemic agent and significance of this plant on secondary complications of diabetes remained unknown. The present study was to investigate the anti-cataractous activity of H. indicus against streptozotocin (STZ)-induced diabetic cataract in rodent model. Root extracts have been prepared and tested for inhibition of rat lens aldose reductase (AR) activity. In addition, its pharmacological potential has been investigated in STZ-induced diabetic cataract. Methanol extract of H. indicus-inhibited AR activity in vitro decreased the blood glucose levels, inhibited the AR activity and delayed the onset and progression of cataract in a dose-dependent manner in in vivo and the antioxidant markers have been normalised. Our results demonstrate that H. indicus has decrease the osmotic stress by inhibiting the AR activity and prevented the loss of antioxidants and delayed the progression of diabetic cataract in STZ-induced diabetic rats.

Clotting factor product administration and same-day occurrence of thrombotic events, as recorded in a large healthcare database during 2008-2013

BACKGROUND

Thrombotic events (TEs) are serious adverse events that can occur following administration of clotting factors (CFs).

OBJECTIVES

To evaluate occurrence of same-day TEs for different CF products and potential risk factors.

METHODS

A retrospective cohort study of individuals exposed to CF products during 2008-2013 was conducted using a large commercial insurance database. CF products were identified by procedure codes, and TEs were ascertained via diagnosis codes. Crude same-day TE rates (per 1000 persons exposed) were estimated overall and by congenital factor deficiency (CFD) status, CF products, age and gender. Multivariable logistic regression analyses were used to control for confounding. Laboratory analysis was used to compare the procoagulant activities of FIX products.

RESULTS

Of 3801 individuals exposed to CFs, 117 (30.8 per 1000) had same-day TEs recorded. The crude same-day TE rate was higher for CF users without CFD, 70.2 (102 of 1452), as compared with those with CFD, 6.4 (15 of 2349) (RR, 11.0; 95% CI, 6.4-18.9). For individuals without CFD, a significantly increased same-day TE risk was identified for factor IX complex (OR, 6.92; 95% CI, 3.11-15.40), factor VIIa (OR, 9.42; 95% CI, 4.99-17.78) and other products when compared with fibrin sealant. An increased risk of a TE was found with older age (≥ 45 years), history of TEs and underlying health conditions. The laboratory identified elevated procoagulant activity in Profilnine(®) and Benefix(®) .

CONCLUSIONS

The study shows an increased same-day TE risk for CF users without CFD and suggests substantial off-label CF use. The study findings also show elevated same-day TE rates for different CF products and suggest the importance of product properties and patient factors.

Crystal structure of 3,9,9-trimethyl-2,3,3a,4,9,9a-hexahydro-1H-cyclopenta[b]quinolin-4-ium chloride

The title mol­ecular salt, C₁₅H₂₂N⁺·Cl⁻, arose as an unexpected product of the reaction between aniline and melanol in the presence of HCl. The central heterocyclic ring has a half-chair conformation and the five-membered ring has an envelope conformation, with the C atom linked to the N atom as the flap. In the crystal, the ions are linked by N—H⋯Cl hydrogen bonds, generating chains propagating in the [100] direction. The crystal studied was a merohedral twin with a 0.64 (3):0.36 (3) domain ratio.

Focal segmental glomerulosclerosis in renal allografts: Is it possible to diagnose the etiology?

Recurrence of FSGS in renal allo grafts is a major cause of graft loss. In this context, we tried to diagnose and classify FSGS in renal allografts. Indications for biopsy included graft dysfunction and/or proteinuria. Three hundred and sixty-three graft biopsies were studied over a period of 2 years. We classified FSGS into recurrent FSGS, new-onset primary FSGS and FSGS secondary to chronic humoral rejection, calcineurin inhibitor toxicity, and nephron loss and hyperfiltration injury. Twenty-four cases were diagnosed as FSGS, constituting 6.6%. Secondary FSGS was the most common FSGS in grafts in our study. Incidence of recurrent FSGS may not be accurate as pretransplant biopsy is available in very few cases.

Thrombotic microangiopathy in renal allografts

Thrombotic microangiopathy (TMA) is a serious complication of renal transplantation. It is a morphological expression of various etiological factors. In a renal allograft, TMA can occur de novo or be a recurrent disease. The aim of this study was to analyze the etiological factors and observe the changing trends of TMA with respect to emerging new etiological factors. We evaluated 131 graft biopsies over a period of 2½ years (2010-2012). All the renal biopsies were formalin fixed, paraffin embedded. Twenty serial sections were studied. Stains routinely used were Hematoxylin and Eosin, Periodic Acid Schiff, Massons Trichrome and Silver Methenamine stains. C4d by immunohistochemical method was done on all graft biopsies. Incidence of TMA in our series was 9.1%. Out of the 12 cases, five were associated with calcineurin inhibitor toxicity, three were diagnosed as acute antibody-mediated rejection, and two were recurrent haemolytic uremic syndrome. One patient developed haemolytic uremic syndrome on treatment with sirolimus and one patient was cytomegalovirus positive on treatment with ganciclovir, developed haemolytic uremic syndrome during treatment course. This study describes a spectrum of etiological factors for thrombotic mciroangiopathy ranging from common cause like calcineurin inhibitor toxicity to rare cause like ganciclovir induced TMA.

Inhibition of aldose reductase by Aegle marmelos and its protective role in diabetic cataract

ETHNOPHARMACOLOGICAL RELEVANCE

Aegle marmelos (L.) Corr. Serr. (Aegle marmelos) leaves were extensively used in the Ayurvedic, Unani and Siddha systems of Indian medicine as an anti-diabetic agent, which serves as hypoglycemic agent. However, the significance of this plant on secondary complications of diabetes such as cataract remained unknown. The aim of the study was to investigate the possible anti-cataractous activity of Aegle marmelos against streptozotocin (STZ) induced diabetic cataract in rats.

MATERIALS AND METHODS

Aegle marmelos leaf extract was prepared using three different solvents (petroleum ether, ethyl acetate and methanol) and tested for inhibition against rat lens aldose reductase (AR), a key enzyme of polyol pathway. Furthermore, the pharmacological potential of Aegle marmelos extract was investigated against osmotic stress induced opacification of lens in ex vivo organ culture and streptozotocin (STZ) induced diabetic cataract in rats.

RESULTS

Ethyl acetate extract of Aegle marmelos inhibited rat lens AR in vitro with an IC50 value of ≈ 15 µg/ml. This extract also prevented the hyperglycemia induced increase in AR activity, sorbitol accumulation and opacification of rat lens in ex vivo lens organ culture. Supplementation of ethyl acetate extract of Aegle marmelos to STZ-induced diabetic rats decreased the blood glucose levels due to hyperglycemia and inhibited the AR activity and delayed cataract progression in dose dependent manner. α-crystallin isolated from diabetic rats fed with Aegle marmelos showed improved chaperone activity than that of isolated from rats naïve to Aegle marmelos.

CONCLUSION

This study indicates that ethyl acetate extract of Aegle marmelos has pharmacologically active components with a potential to inhibit rat lens AR and consequential decrease in osmotic stress. Besides this, the present study also demonstrates that the extract prevented loss of antioxidants contributing to the integrity of α-crystallin's chaperone activity and thereby delaying cataract.

Active safety monitoring of newly marketed medications in a distributed data network: application of a semi-automated monitoring system

We developed a semi-automated active monitoring system that uses sequential matched-cohort analyses to assess drug safety across a distributed network of longitudinal electronic health-care data. In a retrospective analysis, we show that the system would have identified cerivastatin-induced rhabdomyolysis. In this study, we evaluated whether the system would generate alerts for three drug-outcome pairs: rosuvastatin and rhabdomyolysis (known null association), rosuvastatin and diabetes mellitus, and telithromycin and hepatotoxicity (two examples for which alerting would be questionable). Over >5 years of monitoring, rate differences (RDs) in comparisons of rosuvastatin with atorvastatin were -0.1 cases of rhabdomyolysis per 1,000 person-years (95% confidence interval (CI): -0.4, 0.1) and -2.2 diabetes cases per 1,000 person-years (95% CI: -6.0, 1.6). The RD for hepatotoxicity comparing telithromycin with azithromycin was 0.3 cases per 1,000 person-years (95% CI: -0.5, 1.0). In a setting in which false positivity is a major concern, the system did not generate alerts for the three drug-outcome pairs.

Is the variant c.422+90G → A in intron 4 of indoleamine 2, 3 -dioxygenase (IDO) gene related to age related cataracts?

PURPOSE

To screen for sequence variations in the IDO gene that encodes indoleamine 2, 3- dioxygenase (IDO), the first rate limiting enzyme involved in the tryptophan catabolism which results in the production of UV filters playing a role in the maintenance of lens transparency.

METHODS

We conducted a case-control study to screen for sequence changes in the IDO gene and associated demographic risk factors in patients with nuclear (NC-110), cortical (CC-110) and Posterior sub capsular (PSC-111) cataracts in comparison to normal controls (210) from Hyderabad, India.

RESULTS

Among the cataract types studied high risk was observed for CC and PSC types in female patients, individuals with low body mass index and smoking habit. Cataract development had early onset more frequently in cases of PSC followed by CC and NC. Screening by single strand conformation polymorphism (SSCP) revealed mobility shifts in 6 of the 331 patient (3 with NC and 3 with PSC) samples which upon sequencing confirmed the presence of G → A transition (c.422+90G → A; rs4613984) in the intron downstream to exon 4 of IDO which was further tested by RFLP analysis using the HhaI restriction enzyme. Of the 6 patients, one with nuclear cataract showed homozygosity and the remaining five showed heterozygosity for the substitution. None of the control samples showed this variation.

CONCLUSIONS

It is possible that the substitution c.422+90G → A; rs4613984 in an intron downstream to exon 4 of IDO may be related with cataract formation among the aged.

Outcome of patients with end stage renal disease admitted to an intensive care unit in India

AIMS

We sought to determine outcome and evaluate performance of Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores upon admission in predicting 30-day mortality of end-stage renal disease (ESRD) patients admitted in ICU.

METHODS

This prospective observational cohort study examined 73 consecutive ESRD patients admitted in an ICU of a tertiary care institute over 15 months. Primary outcome measure was 30-day mortality. Data on patient characteristics, reason for ICU admission, cause of ESRD, mode of renal replacement, and use of mechanical ventilation (MV) or inotropes were recorded. The APACHE 2 and SOFA scores were calculated based on admission characteristics.

RESULTS

First-day median APACHE II, SOFA, and APACHE II-predicted hospital mortality rates were 26 (14-49), 7 (4-17), and 56.9% (18.6-97.4%), respectively. Observed ICU and 30-day mortality rates were 27.4%, and 41.1%, respectively. During the ICU course, MV and inotropic support was required in 27 (37%) and 23 (35.1%) patients, respectively. Need for MV (p < 0.001) and inotropic support (p < 0.001) were predictors of 30-day mortality in univariate analysis. Area under receiver operating characteristic curve for APACHE II in predicting 30-day mortality was 0.86 (95% CI, 0.76-0.93) compared with 0.92 (95% CI, 0.83-0.97) for SOFA score (p = 0.16).

CONCLUSIONS

Outcome of ESRD patients admitted to ICU is poor, especially if they require other organ support. APACHE II and SOFA scores perform well as predictors of 30-day mortality.

Peritoneal dialysis in developing countries

Peritoneal dialysis (PD) is acknowledged worldwide as a well-accepted form of renal replacement therapy (RRT) for end-stage renal disease (ESRD). Ideally, PD should be the preferred modality of RRT for ESRD in developing countries due to its many inherent advantages. Some of these are cost savings (especially if PD fluids are manufactured locally or in a neighboring country), superior rehabilitation and quality of life (QOL), home-based therapy even in rural settings, avoidance of hospital based treatment and the need for expensive machinery, and freedom from serious infections (hepatitis B and C). However, this is not the ground reality, due to certain preconceived notions of the health care givers and governmental agencies in these countries. With an inexplicable stagnation or decline of PD numbers in the developed world, the future of PD will depend on its popularization in Latin America and in Asia especially countries such as China and India, with a combined population of 2.5 billion and the two fastest growing economies worldwide. A holistic approach to tackle the issues in the developing countries, which may vary from region to region, is critical in popularizing PD and establishing PD as the first-choice RRT for ESRD. At our center, we have been pursuing a 'PD first' policy and promoting PD as the therapy of choice for various situations in the management of renal failure. We use certain novel strategies, which we hope can help PD centers in other developing countries working under similar constraints. The success of a PD program depends on a multitude of factors that are interlinked and inseparable. Each program needs to identify its strengths, special circumstances, and deficiencies, and then to strategize accordingly. Ultimately, teamwork is the 'mantra' for a successful outcome, the patient being central to all endeavors. A belief and a passion for PD are the fountainhead and cornerstone on which to build a quality PD program.

A validated chiral LC method for the enantiomeric separation of Zolmitriptan key intermediate, ZTR-5

A new and accurate chiral liquid chromatographic method was described for the enantiomeric separation of ZTR-5 [(4S)-4-(4-aminobenzyl)-2-oxazolidinone, (S)-isomer], a key intermediate of Zolmitriptan in bulk drugs. The enantiomers of ZTR-5 were baseline resolved on a Chiralpak AD-H (250 mm x 4.6 mm, 5 microm) column using a mobile phase system containing hexane:ethanol (70:30, v/v). The resolution between the enantiomers was not less than four and interestingly distomer was eluted prior to eutomer. The limit of detection and limit of quantification of (4R)-4-(4-aminobenzyl)-2-oxazolidinone [(R)-isomer] were found to be 250 and 750 ng/ml, respectively, for 10 microl injection volume. The percentage recovery of (R)-isomer ranged from 92.0 to 105.6 in the bulk drug samples of ZTR-5. The validated method yielded good results regarding precision, linearity, accuracy and ruggedness. The proposed method was found to be suitable and accurate for the quantitative determination of (R)-isomer in bulk drug samples of ZTR-5.

A stability indicating LC method for zolmitriptan

A gradient, reversed-phase liquid chromatographic (RP-LC) assay method was developed for the quantitative determination of zolmitriptan, used to treat severe migraine headaches. The developed method is also applicable for the related substances determination in bulk drugs. The chromatographic separation was achieved on a Waters X Terra RP18, 250 mm x 4.6 mm, 5 microm column. The gradient LC method employs solutions A and B as mobile phase. The solution A contains a mixture of phosphate buffer pH 9.85:methanol:acetonitrile (70:20:10, v/v/v) and solution B contains a mixture of phosphate buffer, pH 9.85:acetonitrile (30:70). The flow rate was 1.0 ml/min and the detection wavelength was 225 nm. In the developed HPLC method, the resolution between zolmitriptan and its potential impurities, namely Imp-1, Imp-2 and Imp-3 was found to be greater than 3. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in alkaline medium and oxidative stress conditions. Degradation product formed during base hydrolysis was found to be Imp-3. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.

A validated chiral LC method for the determination of Zolmitriptan and its potential impurities

A new, accurate and reliable chiral HPLC method was developed for the determination of Zolmitriptan, (4S)-4-[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl] methyl]-2-oxazolidinone an antimigraine agent and its potential impurities namely (4R)-4-[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl] methyl]-2-oxazolidinone [(R)-enantiomer] and (4S)-4-(4-aminobenzyl)-2-oxazolidinone (Imp-1) in pharmaceutical formulations and in bulk drugs. HPLC separation was carried out by normal phase chromatography with a mobile phase composed of hexane:isopropanol:methanol:diethylamine in the ratio (75:10:15:0.1, v/v/v/v) pumped at a flow rate of 1.0 ml/min on a Chiralpak AD-H column. Zolmitriptan and its potential impurities were baseline resolved in the optimized method. The presence of diethylamine in the mobile phase has played a key role in achieving chromatographic resolution between the enantiomers and also in enhancing chromatographic efficiency. The developed method was also found to be selective under exposed conditions UV light and 60 degrees C. The developed method was completely validated and proved to be robust. The values of the limit of detection (LOD) and limit of quantification (LOQ) of (R)-enantiomer and Imp-1 were 100, 250 ng/ml and 30, 1000 ng/ml, respectively, for 10 microl injection volume. The validated method yielded good results regarding selectivity, linearity, precision, accuracy and ruggedness. Zolmitriptan sample solution and mobile phase are found to be stable for at least 24 h. The proposed method was found to be suitable and accurate for the quantitative determination of Zolmitriptan and its impurities namely (R)-enantiomer and Imp-1 in bulk drugs and commercial formulations.

A bioactive metabolite of benzo[a]pyrene, benzo[a]pyrene-7,8-dione, selectively alters microsomal Ca2+ transport and ryanodine receptor function

Polycyclic aromatic hydrocarbons are environmental pollutants known to be carcinogenic and immunotoxic. In intact cell assays, benzo[a]pyrene (B[a]P) disrupts Ca(2+) homeostasis in both immune and nonimmune cells, but the molecular mechanism is undefined. In this study, B[a]P and five metabolites are examined for their ability to alter Ca(2+) transport across microsomal membranes. Using a well-defined model system, junctional SR vesicles from skeletal muscle, we show that a single o-quinone metabolite of B[a]P, B[a]P-7,8-dione, can account for altered Ca(2+) transport across microsomal membranes. B[a]P-7,8-dione induces net Ca(2+) release from actively loaded vesicles in a dose-, time-, and Ca(2+)-dependent manner. In the presence of 5 microM extravesicular Ca(2+), B[a]P-7,8-dione exhibited threshold and EC(50) values of 0.4 and 2 microM, respectively, and a maximal release rate of 2 micromol of Ca(2+) min(-1) mg(-1). The mechanism by which B[a]P-7,8-dione enhanced Ca(2+) efflux was further investigated by measuring macroscopic fluxes and single RyR1 channels reconstituted in bilayer lipid membranes and direct measurements of SERCA catalytic activity. B[a]P-7,8-dione (< or = 20 microM) had no measurable effect on initial rates of Ca(2+) accumulation in the presence of ruthenium red to block ryanodine receptor (RyR1), nor did it alter Ca(2+)-dependent (thapsigargin-sensitive) ATPase activity. B[a]P-7,8-dione selectively altered the function of RyR1 in a time-dependent diphasic manner, first activating then inhibiting channel activity. Considering that RyR1 and its two alternate isoforms are broadly expressed in mammalian cells and their important role in Ca(2+)-signaling, the present results reveal a mechanism by which metabolic bioactivation of B[a]P may mediate RyR dysfunction of pathophysiological significance.

Ventilatory responses to hypercapnia and hypoxia in relatives of patients with the obesity hypoventilation syndrome

BACKGROUND

It is unclear why some morbidly obese individuals have waking alveolar hypoventilation while others with similar obesity do not. Some evidence suggests that patients with the obesity hypoventilation syndrome (OHS) may have a measurable premorbid impairment of ventilatory chemoresponsiveness. Such an impairment of ventilatory chemoresponsiveness in OHS, however, may be an acquired and reversible consequence of severe obstructive sleep apnoea (OSA). We hypothesised that, in patients with OHS who do not have coincident severe OSA, there may be a familial impairment in ventilatory responses to hypoxia and hypercapnia.

METHODS

Sixteen first degree relatives of seven patients with OHS without severe OSA (mean (SD) age 40 (16) years, body mass index (BMI) 30 (6) kg/m(2)) and 16 subjects matched for age and BMI without OHS or OSA were studied. Selection criteria included normal arterial blood gas tensions and lung function tests and absence of sleep apnoea on overnight polysomnography. Ventilatory responses to isocapnic hypoxia and to hyperoxic hypercapnia were compared between the two groups.

RESULTS

The slope of the ventilatory response to hypercapnia was similar in the relatives (mean 2.33 l/min/mm Hg) and in the control subjects (2.12 l/min/mm Hg), mean difference 0.2 l/min/mm Hg, 95% confidence interval (CI) for the difference -0.5 to 0.9 l/min/mm Hg, p=0.5. The hypoxic ventilatory response was also similar between the two groups (slope factor A: 379.1 l/min * mm Hg for relatives and 373.4 l/min * mm Hg for controls; mean difference 5.7 l/min * mm Hg; 95% CI -282 to 293 l/min * mm Hg, p=0.7; slope of the linear regression line of the fall in oxygen saturation and increase in minute ventilation: 2.01 l/min/% desaturation in relatives, 1.15 l/min/% desaturation in controls; mean difference 0. 5 l/min/% desaturation; 95% CI -1.7 to 0.7 l/min/% desaturation, p=0. 8).

CONCLUSION

There is no evidence of impaired ventilatory chemoresponsiveness in first degree relatives of patients with OHS compared with age and BMI matched control subjects.

Role of respiratory function in exercise limitation in chronic heart failure

OBJECTIVE

To test the hypothesis that respiratory function contributes to limit maximal exercise performance in patients with chronic heart failure by using the technique of dead space loading during exercise.

DESIGN

Blinded subjects underwent two maximal incremental exercise tests in random order on an upright bicycle ergometer: one with and one without added dead space.

SETTING

: Tertiary-care university teaching hospital.

SUBJECTS

Seven patients with stable chronic heart failure (mean +/- SEM left ventricular ejection fraction, 27 +/- 3%).

RESULTS

Subjects were able to significantly increase their peak minute ventilation during exercise with added dead space when compared with control exercise (57.4 +/- 5.9 vs 50.0 +/- 5.6 L/min; p < 0.05). Peak oxygen uptake, workload, heart rate, and exercise duration were not significantly different between the added dead space and control tests. Breathing pattern was significantly deeper and slower at matched levels of ventilation during exercise with added dead space.

CONCLUSION

Because patients with chronic heart failure had significant ventilatory reserve at the end of exercise and were able to further increase their maximal minute ventilation, we conclude that respiratory function does not contribute to limitation of exercise in patients with chronic heart failure.

Pyknodysostosis: a report of two siblings with unusual manifestations

We report pyknodysostosis presenting as extramedullary haematopoiesis in one of two siblings and as obstructive airway disease in the other. Visceral manifestations are rare and have been reported in only two cases in the Indian literature. They have often been mistaken for osteopetrosis, haemolytic anaemia and other osteochondrodystrophies. The cases we report illustrate that, though the physical characteristics may be similar, it is the radiological features that are typical and help establish the diagnosis.

Positional treatment vs continuous positive airway pressure in patients with positional obstructive sleep apnea syndrome

OBJECTIVES

The aim of this study was to compare the relative efficacy of continuous positive airway pressure (CPAP) and positional treatment in the management of positional obstructive sleep apnea (OSA), using objective outcome measures.

DESIGN

A prospective, randomized, single blind crossover comparison of CPAP and positional treatment for 2 weeks each.

SETTING

A university teaching hospital.

PATIENTS

Thirteen patients with positional OSA, aged (mean+/-SD) 51+/-9 years, with an apnea-hypopnea index (AHI) of 17+/-8.

MEASUREMENTS

(1) Daily Epworth Sleepiness Scale scores; (2) overnight polysomnography, an objective assessment of sleep quality and AHI; (3) maintenance of wakefulness testing; (4) psychometric test battery; (5) mood scales; (6) quality-of-life questionnaires; and (7) individual patient's treatment preference.

RESULTS

Positional treatment was highly effective in reducing time spent supine (median, 0; range, 0 to 32 min). The AHI was lower (mean difference, 6.1; 95% confidence interval [CI], 2 to 10.2; p = 0.007), and the minimum oxygen saturation was higher (4%; 95% CI, 1% to 8%; p = 0.02) on CPAP as compared with positional treatment. There was no significant difference, however, in sleep architecture, Epworth Sleepiness Scale scores, maintenance of wakefulness testing sleep latency, psychometric test performance, mood scales, or quality-of-life measures.

CONCLUSION

Positional treatment and CPAP have similar efficacy in the treatment of patients with positional OSA.

Continuous positive airway pressure requirement during the first month of treatment in patients with severe obstructive sleep apnea

OBJECTIVES

(1) To compare the continuous positive airway pressure (CPAP) requirement at the time of diagnosis (T0), after 2 weeks (T2), and after 4 weeks (T4) of CPAP treatment, in patients with severe obstructive sleep apnea (OSA); and (2) to assess whether any alteration in CPAP requirement over the first 4 weeks of CPAP treatment would influence daytime alertness, subjective sleepiness, or mood.

DESIGN

A prospective, controlled, single-blind crossover study.

SETTING

University teaching hospital.

PATIENTS

Ten patients with newly diagnosed and previously untreated severe OSA (aged 52+/-9 years, apnea hypopnea index [AHI] of 99+/-31) and subsequently 10 control patients (aged 52+/-11 years, AHI 85+/-17).

MEASUREMENTS

Overnight polysomnography with CPAP titration to determine the CPAP requirement, which was standardized for body position and sleep stage, on all three occasions (T0, T2, T4). Objective sleep quality, daytime alertness, subjective sleepiness (Epworth Sleepiness Scale), and mood (Hospital Anxiety and Depression Scale).

RESULTS

CPAP requirement decreased from T0 to T2 (median difference, 1.5 cm H2O, 95% confidence interval [CI], 1.1 to 2.7 cm H2O, p=0.0004) and did not differ between T2 and T4. Use of the lower CPAP pressure during T2 to T4 was associated with a decrease in Epworth scale (mean difference, 2.6, 95% CI, 1.2 to 4; p=0.01) and anxiety (median change, 2; 95% CI, 0.5 to 2.9, p=0.03) scores, as compared with the first 2 weeks. Daytime alertness did not differ between T0 to T2 and T2 to T4.

CONCLUSION

CPAP requirement falls within 2 weeks of starting CPAP treatment. A change to the lower required CPAP was not associated with any deterioration in daytime alertness but was associated with small subjective improvements in sleepiness and mood.

Role of hypoxemia and pulmonary mechanics in exercise limitation in interstitial lung disease

We have previously shown that respiratory factors (arterial hypoxemia and/or pulmonary mechanics) contribute to limit maximal incremental exercise in interstitial lung disease (ILD). In this study, we tested the hypothesis that arterial hypoxemia, not pulmonary mechanics, primarily limits maximal exercise in subjects with ILD. Seven subjects with ILD underwent two incremental exercise tests in random order. Test 1: breathing room air (RA); Test 2: breathing 60% O2 with added external dead space (O2VD). Added VD was used to prevent the fall in minute ventilation (VI) while breathing O2. All subjects demonstrated impaired exercise performance (maximal oxygen uptake [VO2], 56 +/- 13% predicted) while breathing RA. There was a significant increase in peak VI (RA, 64.9 +/- 22.3 L/min versus O2VD, 71.0 +/- 20.6; p < 0.05), maximal work rate (RA, 99 +/- 12 watts versus O2VD, 109 +/- 15 watts; p < 0.01), exercise duration (RA, 383 +/- 67 s versus O2VD; 426 +/- 72 s; p < 0.0005) and maximal VO2 (RA, 1.25 +/- 0.21 L/min versus O2VD, 1.39 +/- 0.26; p < 0.05) during the O2VD exercise test. There was a significant correlation between the percent increase in exercise duration during the O2VD test and the DLCO (r = -0.813, p < 0.05). At matched levels of ventilation, subjects demonstrated a significantly deeper and slower pattern of breathing during the O2VD test. Because subjects with ILD were able to further improve their exercise and further increase their VI during the O2VD exercise study, we conclude that arterial hypoxemia, and not respiratory mechanics, predominantly limits maximal incremental exercise in subjects with ILD.

Low-dose nebulized morphine does not improve exercise in interstitial lung disease

Recent reports have suggested that low-dose nebulized morphine may improve exercise tolerance in patients with interstitial lung disease (ILD) by acting on peripheral opioid-sensitive pulmonary receptors. We therefore examined whether the administration of low-dose nebulized morphine would influence dyspnea or the breathing pattern during exercise of subjects with ILD and improve their exercise performance. Each of six subjects with ILD underwent three maximal incremental cycle ergometer tests, each test separated from the last by at least 3 d. Each exercise test was similar except that 30 min before exercise, the subjects received nebulized saline (control), morphine 2.5 mg, or morphine 5.0 mg, respectively, in double-blinded fashion. No significant differences were noted in exercise duration, maximal workload, or sense of dyspnea at the end of exercise in the control test and the tests with either morphine 2.5 mg or morphine 5.0 mg. Nor were significant differences noted in resting, submaximal, or end-exercise measurements of oxygen uptake (VO2), carbon dioxide output (VCO2), end-tidal CO2 (PETCO2), oxygen saturation (SaO2), minute ventilation (VI), respiratory frequency (f), tidal volume (VT), or heart rate (HR) in the three tests. Low-dose nebulized morphine did not alter the subjects' breathing pattern or affect the relationship between dyspnea and ventilation during exercise. No significant side effects were noted. The administration of low-dose nebulized morphine to subjects with ILD neither relieves their dyspnea during exercise nor improves their maximal exercise performance.

Oxygen improves maximal exercise performance in interstitial lung disease

We examined whether arterial hypoxemia impairs incremental exercise performance in subjects with interstitial lung disease (ILD). Seven subjects underwent two incremental exercise tests on a bicycle ergometer in random order; one while breathing room air (RA), and the other while breathing 60% O2. Maximal exercise performance was impaired in all subjects: maximal oxygen uptake (peak VO2) was 56 +/- 4% predicted (+/- SEM); and all subjects demonstrated significant arterial oxygen desaturation during exercise breathing RA (mean 11 +/- 1%). Breathing 60% O2 during exercise resulted in a significant increase in peak VO2 (RA: 1.32 +/- 0.05 L/min; O2: 1.58 +/- 0.08 L/min; p < 0.05), exercise duration (RA: 390 +/- 21 s; O2: 458 +/- 24 s; p < 0.01) and maximal work load (RA: 112 +/- 6 watts; O2: 129 +/- 6 watts; p < 0.005). There was no significant difference in maximal minute ventilation (VI) achieved at the end of both tests. At matched ventilation (90% peak VI from the RA test), respiratory frequency (f) was significantly higher (RA: 33 +/- 2 breaths/min; O2: 35 +/- 2 breaths/min; p < 0.05), and tidal volume (VT) significantly lower (RA: 1.72 +/- 0.15 L; O2: 1.64 +/- 0.12; p < 0.05) when subjects exercised breathing oxygen. We conclude that arterial hypoxemia significantly impairs incremental exercise performance in subjects with ILD, but that mechanisms other than arterial oxygen desaturation are responsible for the rapid, shallow breathing pattern these subjects adopt during exercise.

Lung volumes and expiratory flow limitation during exercise in interstitial lung disease

Lung volumes were measured at rest and during exercise by an open-circuit N2-washout technique in patients with interstitial lung disease (ILD). Exercise tidal flow-volume (F-V) curves were also compared with maximal F-V curves to investigate whether these patients demonstrated flow limitation. Seven patients underwent 4 min of constant work rate bicycle ergometer exercise at 40, 70, and 90% of their previously determined maximal work rates. End-expiratory lung volume and total lung capacity were measured at rest and near the end of each period of exercise. There was no significant change in end-expiratory lung volume or total lung capacity when resting measurements were compared with measurements at 40, 70, and 90% work rates. During exercise, expiratory flow limitation was evident in four patients who reported stopping exercise because of dyspnea. In the remaining patients who discontinued exercise because of leg fatigue, no flow limitation was evident. In all patients, the mean ratio of maximal minute ventilation to maximal ventilatory capacity (calculated from maximal F-V curves) was 67%. We conclude that lung volumes during exercise do not significantly differ from those at rest in this population and that patients with ILD may demonstrate expiratory flow limitation during exercise. Furthermore, because most patients with ILD are not breathing near their maximal ventilatory capacity at the end of exercise, we suggest that respiratory mechanics are not the primary cause of their exercise limitation.

Reactivation disease: the commonest form of tuberculous pleural effusion in Edinburgh, 1980-1991

From 1980-1991 82 (7.2%) of 1134 tuberculosis notifications in Edinburgh were for pleural effusion. Study of the available records of 62 cases satisfying defined diagnostic criteria identified 14 cases (6 M, 8 F) with a mean age of 27.6 years (range 11-51 years) of primary tuberculous effusion and 25 cases (21 M, 4 F) with a mean age of 51 years (range 19-79 years) with pleural effusion due to reactivation disease. Twenty-three patients (19 M, 4 F) with a mean age of 48.9 years (range 25-85 years) defied classification. Symptoms, associated and diagnostic test findings were similar in all three groups of patients. Parenchymal radiographic shadowing was seen in 1/14 primary, 16/25 reactivation and 3/25 unclassified pleural effusions. Twenty-three of 30 patients treated with corticosteroids showed no residual radiographic abnormality compared to 17/30 not so treated (P < 0.06). Reactivation disease is currently a commoner cause of tuberculous pleural effusion than primary disease in Edinburgh. We suggest that the unclassified cases, so similar in age and sex to the defined reactivation disease cases, also represent largely extrapulmonary reactivation disease occurring in middle age.

Dot blot hybridization assay for the detection of duck hepatitis B virus DNA among healthy Indian country ducks

A DNA molecular hybridization technique employing Duck Hepatitis B Virus (DHBV) DNA of 3.0 kilobase pairs as a probe was used to screen for the presence of DHBV DNA in blood samples, collected from 90 apparently healthy Indian country ducks. Six out of 90 ducks showed positivity for DHBV DNA in serum (5.4%) and only 4 out of 6 DHBV DNA positive ducks answered in Counter Immuno Electrophoresis (CIEP) using specific antibody against DHBV surface antigen raised in Guinea pig. The results indicate the pilot observation that (a) DHBV carrier status exists to a tune of 5.4% among apparently healthy Indian country ducks also and (b) DHBV probe can be employed as a sensitive and reliable assay for DHBV DNA detection in DHBV infected ducks.

Duck hepatitis B virus (DHBV) infection in Indian domestic ducks: a pilot study

One hundred and two apparently healthy Indian domestic ducks from the Poultry Research Station, Madras were screened for duck hepatitis B virus (DHBV) infection by; 1. screening for the duck hepatitis B virus surface antigen (DHBsAg) in their sera using hepatitis B virus (HBV) reagents, 2. screening for DHBsAg using specific duck hepatitis B virus (DHBV) reagents and 3. demonstration of DHBV DNA using DHBV DNA probe by dot blot hybridisation. While 5 ducks (4.9%) were consistently positive with HBV reagents, use of DHBV reagents showed a total of 4 ducks (including 3 of the above 5) to be positive for DHBsAg. DNA hybridisation showed 6 ducks to be positive for DHBV DNA. On clinical examination, 5 out of these 6 ducks did not reveal abnormalities, the other one showed hepatomegaly and ascites. Post-mortem studies showed the presence of nodules on the surface of the liver in all 5 which were positive with HBV reagents including the one with hepatomegaly. On histopathological evaluation, they were found to be hepatocellular carcinoma with or without bile duct carcinoma. The present study is a pilot report on the occurrence of DHBV infection in Indian domestic ducks and the possibility of antigenic cross reactivity between human HBV and duck hepatitis B virus antigens.

In vitro effect of intravenous immunoglobulin on serum opsonic activity in normal & intrauterine growth retarded neonates

In vitro effect of intravenous immunoglobulin (IVIG), Intraglobin F, on serum opsonic activity against Staphylococcus aureus was studied in 26 full term normal healthy neonates and 18 intrauterine growth retarded (IUGR) neonates by the polymorphonuclear leucocyte overlay method (requiring only a few drops of blood). Cord IgG and IgM levels were determined by single radial immunodiffusion. Serum opsonic activity against Staph. aureus was significantly lower in the IUGR neonates (49.1 +/- 0.89), as compared to that in normal neonates (61.96 +/- 0.73; P less than 0.001). Immunoglobulin supplementation in vitro at a concentration of 5 g/dl significantly enhanced the opsonic activity of IUGR neonate sera. Cord IgG levels of IUGR neonates were significantly lower (P less than 0.01) than IgG levels of normal neonates. No significant difference was observed in cord IgM levels between the normal and IUGR neonates.