Bismuth ferrite based acetone gas sensor: evaluation of graphene oxide loading

We report a BiFeO3/graphene oxide (BFO/GO) perovskite, synthesized using a CTAB-functionalized glycine combustion route, as a potential material for acetone gas sensing applications. The physicochemical properties of the developed perovskite were analysed using XRD, FE-SEM, TEM, HRTEM, EDAX and XPS. The gas sensing performance was analysed for various test gases, including ethanol, acetone, propanol, ammonia, nitric acid, hydrogen sulphide and trimethylamine at a concentration of 500 ppm. Among the test gases, the developed BFO showed the best selectivity towards acetone, with a response of 61% at an operating temperature of 250 °C. All the GO-loaded BFO samples showed an improved gas sensing performance compared with pristine BFO in terms of sensitivity, the response/recovery times, the transient response curves and the stability. The 1 wt% GO-loaded BiFeO3 sensor showed the highest sensitivity of 89% towards acetone (500 ppm) at an operating temperature of 250 °C. These results show that the developed perovskites have significant potential for use in acetone gas sensing applications.

Electrical transport properties of [(1 - x)succinonitrile:xpoly(ethylene oxide)]-LiCF3SO3-Co[tris-(2,2'-bipyridine)]3(TFSI)2-Co[tris-(2,2'-bipyridine)]3(TFSI)3 solid redox mediators

A solid redox mediator (solid electrolyte) with an electrical conductivity (σ25°C) greater than 10-4 S cm-1 is an essential requirement for a dye-sensitized solar cell in the harsh weather of Gulf countries. This paper reports the electrical properties of solid redox mediators prepared using highly dissociable ionic salts: Co[tris-(2,2'-bipyridine)]3(TFSI)2, Co[tris-(2,2'-bipyridine)]3(TFSI)3, and LiCF3SO3 as a source of Co2+, Co3+, and Li+ ions, respectively, in a solid matrix: [(1 - x)succinonitrile:xpoly(ethylene oxide)], where x = 0, 0.5, and 1 in weight fraction. In the presence of large size of cations (Co2+ and Co3+) and large-sized and weakly-coordinated anions (TFSI- and CF3SO3-), only the succinonitrile-poly(ethylene oxide) blend (x = 0.5) resulted in highly conductive amorphous regions with σ25°C of 4.7 × 10-4 S cm-1 for EO/Li+ = 108.4 and 3.1 × 10-4 S cm-1 for EO/Li+ = 216.8. These values are slightly lower than 1.5 × 10-3 S cm-1 for x = 0 and higher than 6.3 × 10-7 S cm-1 for x = 1. Only blend-based electrolytes exhibited a downward curve in the log σ-T-1 plot, a low value of pseudo-activation energy (0.06 eV), a high degree of transparency, and high thermal stability, making it useful for device applications.

Evaluation of oncology infusion pharmacy practices: A nationwide survey

PURPOSE

Oncology care continues to evolve at a rapid pace including provision of infusion-based care. There is currently a lack of robust metrics around oncology infusion centers and pharmacy practice. The workgroup completed a nationwide survey to learn about oncology-based infusion pharmacy services offered. The objective was to highlight consistent, measureable oncology-based infusion pharmacy metrics that will provide a foundation to describe overall productivity including emphasis on high patient-safety standards.

METHODS

A nationwide survey was developed via a workgroup within the Vizient Pharmacy Cancer Care Group beginning in April 2019 and conducted electronically via the Vizient Pharmacy Network from September to November 2020. The survey was designed to capture a number of key metrics related to oncology-based infusion pharmacy services.

RESULTS

Forty-one sites responded to the survey. Responses highlighted hours of operation (median = 11.5), number of infusion chairs (median = 45). Staffing metrics included 7.1 pharmacist full-time equivalent (FTE) and 7.6 technician FTE per week. 80.5% of sites had cleanrooms and 95.1% reported both hazardous and nonhazardous compounding hoods. 68.3% of sites reported using intravenous (IV) technology, 50.0% measured turnaround time, and 31.4% prepared treatment medications in advance.

CONCLUSION

There was variability among oncology infusion pharmacy practices in regard to survey responses among sites. The survey results highlight the need for standardization of established productivity metrics across oncology infusion pharmacies in order to improve efficiency and contain costs in the changing oncology landscape. The survey provides insight into oncology infusion pharmacy practices nationwide and provides information for pharmacy leaders to help guide their practices.

Evaluation of Structural, Magnetic, and Electromagnetic Properties of Co2+-Substituted NiCuZn Ferrites

We report citrate gel-assisted autocombusted spinel-type Co2+-substituted NiCuZn ferrites and their electromagnetic properties. Several complementary techniques were used to investigate the influence of Co on structural and electromagnetic properties of Ni0.25-xCoxCu0.20Zn0.55Fe2O4 with x = 0.00-0.25 (step of 0.05). XRD analysis confirmed the highly crystalline single-phase cubic spinel structure with a prominent peak of the (311) plane. FE-SEM analysis showed the loss of porous gel structure (colloidal backbone) due to addition of cobalt into the present ferrite system. The EDAX analysis confirmed the presence of Ni, Cu, Zn, Co, and O in accordance with the relative stoichiometry of Co-substituted NiCuZn ferrite. The electrical resistivity of ferrites is observed to decrease when Co2+ ions are substituted, regardless of AC and DC. The dielectric properties (ε' and ε″) of ferrites exhibited a consistent decrease as the frequency increased, and this trend persisted even at higher frequencies. VSM analysis showed the normal magnetic hysteresis of the developed ferrite system. At x = 0.05, the saturation magnetization of the ferrite was obtained to be the highest among the other substitution levels of Co. The Curie temperature fell down when there was a higher concentration of cobalt in the ferrite system (x = 0.20). After reaching a specific temperature, the μi values decreased abruptly, with an increase in the temperature. The steady state may be deduced from the fact that the constant real component of the initial permeability, μ', remained unchanged. However, with decreasing frequency, the values of μ″ decreased dramatically. The present NiCuZn ferrite series displays the enhanced dielectric properties suggesting the capability of potential candidates for microwave absorption applications with enhanced electromagnetic properties.

Structural, Thermal, and Electrical Properties of Poly(Ethylene Oxide)-Tetramethyl Succinonitrile Blend for Redox Mediators

An all-solid−state dye-sensitized solar cell is one of the non-fossil fuel-based electrochemical devices for electricity generation in a high-temperature region. This device utilizes a redox mediator, which is a fast ion-conducting solid polymer electrolyte (SPE). The SPE makes the device economical, thinner, and safer in high-temperature regions. The SPE generally has a form of matrix−plasticizer−redox salts. Succinonitrile (SN) is generally employed as a plasticizer for reducing the crystallinity of poly(ethylene oxide), abbreviated as PEO, a common polymeric matrix. In the present paper, the structural and thermal properties of tetramethyl succinonitrile (TMSN) were compared with SN for its application as a solid plasticizer. TMSN and SN both are plastic crystals. TMSN has four methyl groups by replacing the hydrogen of the SN, resulting in higher molecular weight, solid−solid phase transition temperature, and melting temperature. We thoroughly studied the structural, thermal, and electrical properties of the [(1−x)PEO: xTMSN] blend for utilizing it as a matrix, where x = 0−0.25 in mole fraction. The FT-IR spectra and XRD patterns of the blends exhibited PEO-alike up to x = 0.15 mole and TMSN-alike for x > 0.15 mole. Differential scanning calorimetry revealed formation of a eutectic phase from x = 0.1 mole and phase separation from x = 0.15 mole. The blends with x = 0.1−0.15 mole had a low value of PEO crystallinity. Thermogravimetric analysis showed thermal stability of the blends up to 75 °C. The blends exhibited electrical conductivity, σ25°C more than 10−9 S cm−1, and Arrhenius behavior (activation energy, ~0.8 eV) in a temperature region, 25−50 °C.

Platinum-coated silicotungstic acid-sulfonated polyvinyl alcohol-polyaniline based hybrid ionic polymer metal composite membrane for bending actuation applications

An electro-stimulus-responsive bending actuator was developed by synthesizing a non-perfluorinated membrane based on silicotungstic acid (SA), sulfonated polyvinyl alcohol (SPVA), and polyaniline (PANI). The membrane was developed via solution casting method. The dry membrane SA/SPVA showed a sufficient ion-exchange potential of 1.6 meq g⁻¹ dry film. The absorption capacity of the membrane after almost 6 h of immersion was found to be ca. 245% at 45 °C. The electroless plating with Pt metal was carried out on both sides of the membrane that delivered an excellent proton conductivity of 1.9 × 10⁻³ S cm⁻¹. Moreover, the scanning electron microscopy (SEM) was conducted to reflect the smooth and consistent surface that can prevent water loss. The water loss capacity of the membrane was found to be ca. 33% at 6 V for 16 min. These results suggest a good actuation output of the ionic polymer metal composite (IPMC) membrane once the electrical potential is applied. The electromechanical characterization displayed a maximum tip displacement of 32 mm at 3 V. A microgripping device based on multifigure IPMC membrane may be developed showing a good potential in micro-robotics.

Tetramethyl Succinonitrile as a Solid Plasticizer in a Poly(Ethylene Oxide)8 -LiI-I2 Solid Polymer Electrolyte

Dye-sensitized solar cell (DSSC) is a promising alternative to the commercially available amorphous silicon-based solar cell because of several advantageous properties. A DSSC with a fast ion conducting solid polymer electrolyte is required for the arid atmosphere of Gulf countries. In this work, we have proposed a new matrix, poly(ethylene oxide)-tetramethyl succinonitrile blend to synthesize a blend-LiI-I₂ solid polymer electrolyte for the DSSC application. The tetramethyl succinonitrile is a member of plastic crystal with a solid-solid phase transition temperature of approximately 71 °C and melting temperature of approximately 170.5 °C. Its molar fraction, 0.1-0.15 is sufficient enough for synthesizing a polymer electrolyte with electrical conductivity of more than 10^-4 S cm^-1 at room temperature. This electrolyte shows Vogel-Tamman-Fulcher type behavior with a low value (∼0.083 eV) of pseudo-activation energy for easy ion transport. The results of FT-IR spectroscopy, XRD, and DSC studies reveal the plasticizing effect of tetramethyl succinonitrile to form an amorphous phase. This electrolyte results in a ∼661% gain in J_SC and thereby a ∼552% gain in the cell efficiency (∼3.5%) with respect to the DSSC prepared with the tetramethyl succinonitrile-free electrolyte. This article is protected by copyright. All rights reserved.

Green synthesis of silk sericin-embedded silver nanoparticles and their antibacterial application against multidrug-resistant pathogens

BACKGROUND

The green synthesis strategy of metallic nanoparticles (NPs) has become popular due to being environmentally friendly. Stable silver nanoparticles (AgNPs) have been synthesized by natural products such as starch, soy protein, various extract of leaves, barks, and roots functioning both as reducing and stabilizing agents. Likewise, silk sericin (SS) is a globular protein discarded in the silk factory might be used for NP synthesis. In this research, we focus on the green synthesis and stabilization of AgNPs by SS as well as assessment of their antibacterial activities against some drug-resistant pathogen.

RESULTS

SS was extracted from Bombyx mori silkworm cocoons in an aqueous medium. 17 w/w% of dry sericin powder with respect to the cocoon's weight was obtained by freeze-drying. Furthermore, AgNPs conjugated to sericin, i.e., SS-capped silver nanoparticles (SS-AgNPs) were synthesized by easy, cost-effective, and environment-friendly methods. The synthesized SS-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction measurement. It has been found from the absorbance of UV-visible spectroscopy that a higher percent of SS-AgNPs was obtained at a higher concentration of silver nitrate solution. FTIR-ATR spectra showed that the carboxylate groups obtained from silk sericin act as a reducing agent for the synthesis of silver nanoparticles, while NH2+ and COO- act as a stabilizer of AgNPs. The X-ray diffractogram of SS-AgNPs was quite different from AgNO3 and sericin due to a change in the crystal structure. The diameter of AgNPs was around 20-70 nm observed using TEM. The synthesized SS-AgNPs exhibited strong antibacterial activity against multidrug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 20μg/mL.

CONCLUSIONS

This study encourages the use of Bombyx mori for the ecofriendly synthesis of SS-AgNPs to control multidrug-resistant microorganisms.

Understanding the Electrical Transport-Structure Relationship and Photovoltaic Properties of a [Succinonitrile-Ionic Liquid]-LiI-I2 Redox Electrolyte

The properties of succinonitrile-based electrolytes can be enhanced by the addition of an ionic liquid (IL). Here, we have reported the relationship between the electrical transport properties and the structure of a new [(1 - x)succinonitrile:xIL]-LiI-I₂ electrolyte, where the mole fraction (x) of the IL (1-butyl-3-methyl imidazolium iodide) was varied from 0 to 40%. Compositional variation revealed the optimum conducting electrolyte (OCE) at x = 10 mol %, possessing an electrical conductivity (σ_25°C) of ∼7.5 mS cm^-1 with an enhancement of ∼369%. The partial replacement of succinonitrile by the IL eliminated the abrupt change in the slope of the log σ vs T ^-1 plot at the melting temperature of the succinonitrile-LiI-I₂ system, showing the Vogel-Tamman-Fulcher-type behavior owing to molecular chain disorder. Raman spectroscopy showed the I₃ ^- concentration nearly twice the I₅ ^- concentration for the OCE. Vibrational spectroscopy exhibited red shifts in the ν_C≡N, ν_CH2 , ν_a,CC, ν_a,N-CH3 , and ν_s,N-butyl modes, indicating an interaction between succinonitrile and the IL. The area ratio A _CH2 /A _C≡N increased slightly for x = 10 mol % (OCE) and largely for x > 10 mol %, indicating an increase in the C-H bond length. These observations indicated that the interaction between succinonitrile and the IL was enhanced at x > 10 mol %, which decreased the electrical conductivity of these electrolytes. Owing to fast ion transport, an OCE-based dye-sensitized solar cell showed a 40-55% decrease in the charge-transfer and Warburg resistances, resulting in ∼139 and ∼122% increases in J _SC and η, respectively.

0734 Does Noise Masking Improve Sleep Consolidation In Patients Weaning From Prolonged Mechanical Ventilation?

Introduction

Sound masking is a noise reduction strategy that adds a mixed-frequency blend of ambient sound to the environment and may improve sleep. Critically ill patients often cite noise as one of the main factors preventing sleep while they are cared for in an intensive care unit (ICU). The effect of sound masking on sleep in patients weaning from prolonged mechanical ventilation is unknown.

Methods

12-hour overnight polysomnography was obtained in eight patients undergoing weaning from prolonged mechanical ventilation. None had hearing impairment, delirium, sedation or agitation. In random order, patients were exposed to sound masking half of the recording time. Noise events were defined a 10dB increase from baseline or any sound peak over 75dB. Arousals or awakenings were attributed to noise if they occurred within 5 seconds of the noise event.

Results

Environmental sound was 61.7± 0.9 dB (mean±SE) during sound masking and 55.9±1.4 dB during no sound masking. During sound masking, there were fewer sound events per hour of sleep when compared to no sound masking (4.1/hr vs 9.3/hr p=0.03). The percentage of sound events leading to a subsequent arousal or awakening with sound masking was less than during no sound masking:11% vs 22% (p=0.04). Arousal index and fragmentation index (arousal and awakenings/hr of sleep) were similar between the two conditions. In a post-study survey, five patients reported improved sleep quality with sound masking while the remaining three reported no difference.

Conclusion

Sound masking decreases sound-induced arousal from sleep in patients being weaned from prolonged mechanical ventilation.

Support

Veterans Administration Research Service

Wunderlichs syndrome in patient with sporadic bilateral angiomyolipomas - case report

We present the case report of bilateral renal angiomyolipomas in a 70-year-old patient. Spontaneous bleeding into the retroperitoneum and hemodynamic instability required an acute surgical revision with a left-sided nephrectomy. The contralateral angiomyolipoma was selectively embolized in the second period and subsequently resected.

Date palm biochar-polymer composites: An investigation of electrical, mechanical, thermal and rheological characteristics

The application of biochar (BC) as a filler in polymers can be viewed as a sustainable approach that incorporates pyrolysed waste based value-added material and simultaneously mitigate bio-waste in a smart way. The overarching aim of this work was to investigate the electrical, mechanical, thermal and rheological properties of biocomposite developed by utilizing date palm waste-derived BC for the reinforcing of polypropylene (PP) matrix. Date palm waste derived BC prepared at (700 and 900°C) were blended at different proportions with polypropylene and the resultant composites (BC/PP) were characterized using an array of techniques (scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infra-red spectroscopy). Additionally the thermal, mechanical, electrical and rheological properties of the BC/PP composites were evaluated at different loading of BC content (from 0 to15% w/w). The mechanical properties of BC/PP composites showed an improvement in the tensile modulus while that of electrical characterization revealed an enhanced electrical conductivity with increased BC loading. Although the BC incorporation into the PP matrix has significantly reduced the total crystallinity of the resulted composites, however; a positive effect on the crystallization temperature (T_c) was observed. The rheological characterization of BC/PP composites revealed that the addition of BC had minimal effect on the storage modulus (G') compared to the neat (PP).

Phoenix dactylifera mediated green synthesis of Cu2O particles for arsenite uptake from water

In this study, an environmentally friendly, cost-effective, and single-step procedure is used for the synthesis of polycrystalline Cu₂O particles with controlled morphologies. Simple sugars are extracted from date fruit pulp (Phoenix dactylifera) and used as a reducing agent for the formation of Cu₂O particles in aqueous medium. The feasibility of this solution is compared with the standard glucose solution. The Cu₂O particles are characterized by electron microscopy, X-ray diffraction, optical absorption and Raman scattering techniques. It is concluded that the morphology of the particles is mainly influenced by the solvents. The obtained Cu₂O particles are then used as an adsorbent to uptake As(III) ions from water. The maximum adsorption capacity (Q_max) is estimated by Langmuir and Freundlich isotherms and it is found that Q_max = 14.3 mg g^-1. Adsorption kinetics study showed that the adsorption equilibrium could be achieved in 1 h and that the purified water meets the standards of World Health Organization (WHO) for acceptable amount of As(III) in drinking water. Adsorption kinetic models showed that the adsorption is chemisorption in nature.

Natural history of early first-trimester pregnancies implanted in Cesarean scars

OBJECTIVE

To describe the ultrasound findings and natural history of pregnancies implanted within or on Cesarean section scars in the first trimester of pregnancy.

METHODS

This was a prospective observational study of 10 women diagnosed with a pregnancy implanted in or on a Cesarean section scar in the first trimester, who declined medical intervention because of their desire to continue the pregnancy. The study population comprised women at < 12 weeks' gestation who were seen in our early pregnancy unit between January 2011 and September 2013. Nine women were followed up by serial ultrasound examinations and had detailed care plans for delivery at King's College Hospital (KCH). One woman was followed up and delivered at another teaching hospital. The first-trimester ultrasound findings were compared with the clinical outcome of the pregnancy.

RESULTS

The nine patients who were followed up at KCH developed ultrasound findings of morbidly adherent placenta (MAP) in the second and third trimesters. All 10 patients were diagnosed with MAP at the time of delivery by Cesarean section. The gestational age at delivery ranged from 26 to 38 weeks. The uterus was conserved in five patients, and Cesarean hysterectomy was performed in the remaining five. All three women with complete implantation of the gestational sac within the scar and two of three cases with placental lakes in the first trimester had hysterectomies. The two cases with bulging of the gestational sac out of the uterine contour had a preterm emergency hysterectomy due to placenta percreta. Histology confirmed placenta accreta in the five hysterectomy specimens. There were no fetal or neonatal complications.

CONCLUSIONS

Implantation of a pregnancy on or in a Cesarean section scar is a precursor of MAP; however, the degree of morbidity associated with this implantation is variable and difficult to predict based on first-trimester ultrasound findings only. The assessment of ongoing pregnancies implanted in Cesarean scars is most beneficial when performed between 7 and 9 weeks' gestation. Complete implantation within the myometrial defect, bulging of the trophoblast from the uterine contour and large placental lakes in the first trimester are ultrasound findings that may predict severe placenta accreta or percreta and consequently a poor outcome.

Conversion of grass biomass into fermentable sugars and its utilization for medium chain length polyhydroxyalkanoate (mcl-PHA) production by Pseudomonas strains

This study investigated the potential of grass biomass as a feedstock for mcl-PHA production. Pretreatments (2% NaOH at 120°C or hot water at 120°C) of perennial ryegrass were employed alone or in combination with sodium chlorite/acetic acid (SC/AA) delignification to evaluate the enzymatic digestibility and subsequent utilization of resultant sugars by Pseudomonas strains. NaOH pretreated sample had better digestibility than raw and hot water treated samples and this hydrolysate supported good growth of all tested strains with limited mcl-PHA (6-17% of cell dry mass (CDM)) accumulation. Digestibility of both untreated and pretreated samples was improved after SC/AA delignification and produced glucose (74-77%) rich hydrolysates. Tested strains accumulated 20-34% of CDM as PHA when these hydrolysates were used as sole carbon and energy source. CDM and PHA yields obtained for these strains when tested with laboratory grade sugars was similar to that achieved with grass derived sugars.

Age, gender, and racial differences in incidence and survival in primary CNS lymphoma

Background:

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extranodal non-Hodgkin lymphoma that accounts for ∼4% of newly diagnosed central nervous system (CNS) tumours. The objective of this study was to analyse the epidemiology, incidence, and outcome of these rare tumours.

Methods:

Primary brain and CNS lymphoma cases were identified from the Surveillance, Epidemiology, and End Results (SEER) research data sets for the years 1980–2008 for analysis of trends in incidence and survival. SEER^*Stat v. 7.0.4 software was used to analyse the data.

Results:

The overall incidence rate of PCNSL was 0.47 per 100 000 person-years. The incidence was significantly higher in males compared with females, blacks aged 0–49 years at diagnosis compared with whites, and whites aged 50 years and older at diagnosis compared with blacks. After a significant decline in incidence between 1995 and 1999, incidence rates rose slightly; those aged 75+ years at diagnosis had the most dramatic increase in incidence rates over time. Five-year survival rates were significantly higher in whites compared with blacks aged 0–49 years at diagnosis, but was primarily driven by white women aged 0–49 years.

Conclusion:

There is an increase in incidence of PCNSL in the elderly, and elderly blacks have lower incidence compared with white population. Survival remains poor and is negatively dominated by factors associated with HIV infection and advanced age.

Management of maternal obesity prior to and during pregnancy

The prevalence of obesity is high and rising worldwide. The greatest prevalence of obesity is found in the western world and in urban developing countries. There is an increased maternal mortality associated with maternal obesity. There are increased risks of most maternal complications in pregnancy including pre-eclampsia, gestational and pre-existing type 2 diabetes mellitus and thromboembolic disorders. There is an increased perinatal mortality associated with maternal obesity; there are increased risks of congenital malformation, fetal macrosomia and indeed risks for the fetus as a child and adult in the years to come. There are increased risks of complications of pregnancy including caesarean section, traumatic delivery and a reduced chance of breastfeeding. Maternal obesity in pregnancy predicts long-term risks for that mother. The management includes increased surveillance for these risks and lifestyle modulation during pregnancy. This includes dietary measures and encouraging modest increase in exercise. Ideally, the mother should achieve closer to an ideal body mass index prior to pregnancy using lifestyle intervention but possibly with pharmacological therapy or bariatric surgery. The ideal weight gain for an obese mother is less than the ideal weight gain for a lean mother.

Pigment synthesizing melanoma (so-called animal type melanoma): a clinicopathological study of 14 cases of a poorly known distinctive variant of melanoma

AIMS

Pigment synthesizing melanoma (so-called animal type melanoma) (PSM) is a rare histopathological variant of melanoma so termed because of prominent melanin production and its similarity to a variant of melanoma seen in grey horses. The aim of this study was to report the clinicopathological characteristics of 14 cases of animal type melanoma.

METHODS AND RESULTS

Six patients were female and eight were male with ages ranging from 5 to 52 years (mean 31 years, median 39 years). The head and neck represented the most common site. The clinical diagnosis was of melanoma in seven cases, blue naevus in three cases, benign naevus in three cases and a pigmented basal cell carcinoma in one case. The histological diagnosis of PSM was predicated on the basis of an asymmetrical, predominantly intradermal tumour formed of deeply pigmented, round or short, spindle-shaped dendritic melanocytes with some degree of hyperchromatism and a single nucleolus. Cytological atypia was always present but was not pronounced. A prominent population of macrophages was invariably present. Four tumours were compound and 10 tumours were predominantly intradermal. The mitotic count was usually low, ranging from 1 to 5 per 10 high-power fields (mean 2). Perineural and lymphovascular invasion was not seen. The Breslow thickness ranged from 1.1 to 7.5 mm (mean 3.3 mm). Follow-up was available in 13 patients. The median follow-up period was 5 years. Six patients had no recurrence, three had local recurrence in the form of satellite nodules adjacent to the scar, four had spread to the regional lymph nodes and one patient had distant metastases to the liver. There were no deaths.

CONCLUSIONS

This study demonstrates that PSM is a distinctive, possible low-grade variant of melanoma usually lacking the histological features predictive of aggressive behaviour seen in ordinary melanoma. It should be managed in the same way as other melanomas with wide local excision.

The changes of metabolic profile and weight during Ramadan fasting

INTRODUCTION

Ramadan is the holiest month in the Islamic calendar and Muslims fast during this month. We designed this study to evaluate the effect of Ramadan fasting on plasma lipids and lipoproteins.

METHODS

This cohort study was performed during Ramadan in December 2002 (Islamic year 1423). The subjects were 81 students of Tehran University of Medical Sciences. We evaluated weight, body mass index (BMI), glucose, triglyceride (TG), cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), and very low density lipoprotein (VLDL), before and after Ramadan.

RESULTS

Body weight and BMI both decreased during Ramadan fasting in both genders. Glucose and HDL decreased and LDL increased significantly during fasting in Ramadan, but there was no significant change in total cholesterol, TG and VLDL. We did not find any association between TG, cholesterol, LDL, VLDL, HDL and the following variables: sex, body weight changes, and two or three instances of meals before Ramadan. Triglyceride level also increased in students with normal BMI while it decreased in overweight subjects.

CONCLUSION

This study indicated that Ramadan fasting led to a decrease in glucose and weight. Although there was a significant reduction in meal frequency, a significant increase in LDL and decrease in HDL was noted during Ramadan. It seems that the effect of Ramadan fasting on serum lipid levels may be closely related to the nutritional diet or biochemical response to starvation.

An unusual case of pneumonia

A previously healthy 37-year-old man was admitted with a two-month history of increasing shortness of breath and high temperature. A chest X-ray demonstrated bibasal shadowing and small bilateral pleural effusions; arterial blood gases demonstrated low pO2. Despite intravenous antibiotics no significant improvement was observed. A high-resolution chest computed tomography showed diffuse ground-glass opacification with segmental and subsegmental airways opacification, indicating fine fibrosis. Subsequently, open lung biopsy showed diffuse alveolar damage and a histopathological diagnosis of acute interstitial pneumonia (Hamman-Rich syndrome) was made. Antibiotics were stopped and high intravenous doses of steroids were given with a dramatic improvement in the patient's breathing and radiographic findings. The pathophysiological mechanisms of acute interstitial pneumonia and current therapeutic options are discussed.

Fatal donor-derived Epstein-Barr virus-associated post-transplant lymphoproliferative disorder following reduced intensity volunteer-unrelated bone marrow transplant for myelodysplastic syndrome

Post-transplant lymphoproliferative disorders (PTLD) are a well recognised complication of conventional haemopoietic stem cell transplantation (HSCT). Reduced intensity HSCT involves intensive immunosuppression to permit engraftment. Thirty reduced intensity transplants with the FBC (fludarabine 150 mg/m2, busulphan 8 mg/m2, CAMPATH-1H 100 mg) protocol have been performed at our centre, with one confirmed EBV-positive PTLD. The female recipient developed a perforated viscus day +191 following HSCT from a volunteer unrelated male donor. A large caecal mass and a retroperitoneal abscess were excised, revealing an EBV-positive diffuse large B cell lymphoma confirmed by FISH to be of donor origin. More experience is required before the risk of PTLD in this setting can be assessed.

Penetration of anticancer drugs through solid tissue: a factor that limits the effectiveness of chemotherapy for solid tumors

Penetration of anticancer agents to cells distant from the vascular system is required for efficacy of cancer chemotherapy against solid tumors. Many solid tumors have a poorly formed blood vascular system with variable rates of blood flow and much larger intercapillary distances than those found in normal tissues. The requirement for drugs to penetrate several layers of tissue might pose a barrier to the effective treatment of solid tumors. Multicellular layers (approximately 200 microm thick) were grown in vitro on Teflon membranes from EMT6 murine and MCF7 human tumors and have been used to quantitate the penetration of four widely used anticancer drugs through solid tissue. The penetration of doxorubicin and mitoxantrone was limited and very slow (<10% of the rate of penetration through the Teflon membrane alone). The penetration of methotrexate and 5-FU was more rapid (approximately 30-50% of the rate of penetration through the Teflon membrane alone), but remains a substantial barrier to the effectiveness of these drugs. Strategies to improve the penetration of anticancer drugs through poorly vascularized tumor tissue have considerable potential to improve the outcome of chemotherapy for solid tumors.

Immuno-histochemical analysis of estrogen receptors on the malignant gallbladder tissue

Sex steroids play an important part in the functioning of normal gallbladder, formation of gallstones and possibly in the pathogenesis of gallbladder cancer. Steroids receptors have been previously demonstrated on normal and malignant gall bladder tissues. To study this phenomenon further, we correlated clinicopathological features and survival with estrogen receptor (ER) status of the tumour in 30 patients with histologically-proven adenocarcinoma of the gallbladder. Estrogen receptor assay was performed immuno-histochemically utilizing Universal Immunoperoxidase Staining Kit. Tumor tissue was obtained either surgically or with fine needle aspiration of the gallbladder mass. There were 27 females and 3 males. Eighteen patients had estrogen receptors expressed on the malignant tissue, 12 were negative. Comparison of clinicopathological characteristics and survival between the two groups demonstrated no significant difference in gender, mean age, marital status and parity. Similarly, presence of gallstones, histologic grade or survival did not correlate with the estrogen receptor status. There is, however, a trend in favour of poorly differentiated tumors being more often receptor negative. Further studies are necessary to elucidate the biologic significance of these receptors.

Changing patterns and re-distribution of antigen in poorly differentiated carcinomas: its implications in tumour diagnosis

The variability of expression of tumour-associated antigens via either antigenic heterogeneity or antigenic modulation presents a basic problem in immunohistochemical diagnosis of poorly/undifferentiated tumours. This work was designed to study antigenic expression on human resected epithelial tumours by a panel of most widely used antibodies (EMA, CEA, AUAI & Cytokeratin) in relation to tumour differentiation and polarization. It was observed that poorly differentiated carcinoma with loss of polarity show homogeneous membrane staining (with antibodies against EMA, CEA & AUAI) in contrast to either apical (luminal) or basolateral membrane staining in well differentiated counterparts. Biochemical studies have shown that apical and basolateral epithelial cell membrane domains have a characteristic set of glycoproteins. Tight junctions are essential for maintaining this functional polarization. It was concluded that structural and functional abnormalities of tight junctions in poorly differentiated carcinomas results in loss of polarity with progressive invasion of the cell surface by antigenic glycoprotein and resultant homogeneous individual cell antigenic expression in poorly differentiated carcinomas. This study demonstrates that antigenic expression on tumour cells is not static, but dynamic and heterogeneity of antigenic expression may well be due to biological factors such as spatial configuration of the lesion.

Is carcinoma breast a different disease in Pakistani population?

Carcinoma of the breast tends to be different in coloured and white races. Is this pattern also expressed in Pakistani population? To answer this query we carried out a retrospectively study of breast cancer on 193 cases who were divided into 2 groups i.e. less than and more than 50 years age groups. In the former group, 93% tumours were of grades II or III and approximately 51% were estrogen receptors negative. In more than 50 years age group, 75% tumors were in grade II and III, with almost 37% being estrogen negative tumors. Majority (75%) of the patients had over 6 cms lump with equal number having positive lymph node status. All these factors point to the fact that besides presenting late, our population has additional unfavourable prognostic factors.

Clinicopathological features and management of immunoproliferative small intestinal disease and primary small intestinal lymphoma in Pakistan

This study was performed to confirm the existence of immunoproliferative small intestinal disease (IPSID) in Pakistan. Clinicopathological features of 12 patients with histologically confirmed disease were analysed. Patients were mostly young males with median age of 24.6 years. Two thirds belonged to poor socioeconomic class. Main presenting features were chronic diarrhoea and weight loss. Eleven patients had radiologic evidence of malabsorption syndrome. Endoscopic findings of mucosal thickening, edema, and flattened villi were present in the majority. Patients had both secretory and non-secretory types of disease. Six patients presented with stage A disease. Four responded to antibiotics or steroids, although mucosal abnormalities persisted in three. Two stage A patients evolved into stage C disease, one was lost to follow-up, the other is alive with disease. Three patients presented with stage B disease. Two responded completely to chemotherapy, the third refused treatment and expired after 16 months. Three patients had stage C disease at diagnosis. They received aggressive combination chemotherapy and remain in complete remission with a median follow-up of 2.2 years. This is the first series of patients with IPSID reported from Pakistan. Clinicopathological features and therapeutic results are consistent with the experience elsewhere. Increased awareness may result in early diagnosis and better management.

Barrett's oesophagus and Helicobacter pylori

In order to demonstrate the presence of Helicobacter pylori in the metaplastic epithelium of Barrett's oesophagus and to evaluate its possible association with this entity, we examined 29 cases of Barrett's oesophagus where concomitant antral biopsies were also available. These cases were compared with an equal number of age and sex matched controls of uncomplicated reflux oesophagitis. H. pylori was present in 11 of 29 cases of Barrett's oesophagus (38%). No increase in the frequency of H. pylori antral gastritis was found in patients of Barrett's oesophagus compared to the control group of uncomplicated reflux oesophagitis. The positivity of Barrett's oesophagus for H. pylori correlated with the presence of H. pylori antral gastritis (P < 0.05), although in two cases of H. pylori-positive Barrett's oesophagus antral biopsies were negative for H. pylori. No difference was found in the severity of inflammatory and dysplastic changes of H. pylori-positive and H. pylori-negative Barrett's oesophagus. Presence of H. pylori does not seem to alter the natural history of Barrett's oesophagus.

Immunohistochemical estrogen receptor determination in human breast carcinoma: correlation with histologic differentiation and age of the patients

An immunohistochemical assay for the measurement of estrogen receptor (ER) has been evaluated on 290 consecutive human breast biopsy and mastectomy specimens in the year 1992 at The Aga Khan University Hospital laboratories. Immunohistochemical localization of estrogen receptor on frozen/paraffin section was scored in a semi-quantitative fashion incorporating both the intensity and the distribution of specific staining. Histologic grading of the tumour was performed according to Bloom's method. In this study, 21% of the tumours were estrogen receptor negative, 15% were weak positive, 25% intermediate positive and 39% strong positive. Fifty percent of the well differentiated tumours showed strong ER positivity against 27% of the poorly differentiated tumours. Seventy eight percent of all negative estrogen receptors were in patients younger than 50 years of age (pre-menopausal group), while 52% of strong estrogen receptor positivity was observed in patients older than 50 years (post- menopausal). This study demonstrates the value of immunohistochemical method to determine the ER status in patients with advanced breast cancer.

Amoebic appendicitis--a rare entity

Appendectomy is the most common surgical procedure performed in routine general surgical practice. However, not all the appendices removed, are submitted for histopathological examination in this part of the world. We reviewed 1400 appendices received by our department from within our hospital and from outside the hospital. Of these 13 cases were reported as amoebic appendicitis. These patients did not have any different clinical presentation from the patients who were reported as acute appendicitis without amoebae. Microscopically these appendices had minimal neutrophil polymorph infiltration accompanied by tissue necrosis and amoebic trophozoites within the appendiceal wall. After histological diagnosis, different tests (IHA and stool examination) were done to exclude a possibility of secondary involvement of the appendix, on 8 patients from our hospital which were negative, thus confirming that these patients had primary appendiceal involvement. Hence we recommend that all the appendices removed should be subjected for histological examination, since ths may help in subsequent management of these patients.

Amoebic brain abscess: a rare but serious complication of Entamoeba histolytica infection

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