Visible and angular interrogation of Kretschmann-based SPR using hybrid Au-ZnO optical sensor for hyperuricemia detection

Uric acid is a waste product of the human body where high levels of it or hyperuricemia can lead to gout, kidney disease and other health issues. In this paper, Finite Difference Time Doman (FDTD) simulation method was used to develop a plasmonic optical sensor to detect uric acid with molarity ranging from 0 to 3.0 mM. A hybrid layer of gold-zinc oxide (Au-ZnO) was used in this Kretschmann-based Surface Plasmon Resonance (K-SPR) technique with angular interrogation at 670 nm and 785 nm visible optical wavelengths. The purpose of this study is to observe the ability of the hybrid material as a sensing performance enhancer for differentiating between healthy and unhealthy uric acid levels based on the refractive index values from previous study. Upon exposure to 670 nm wavelength, the average sensitivity of this sensor was found to be 0.028°/mM with a linearity of 98.67 % and Q-factor value of 0.0053 mM - 1 . While at 785 nm, the average sensitivity is equal to 0.0193°/mM with slightly lower linearity at 94.46 % and Q-factor value of 0.0076 mM - 1 . The results have proven the ability of hybrid material Au-ZnO as a sensing performance enhancer for detecting uric acid when compared with bare Au and can be further explored in experimental work.

Geometrical Characterisation of TiO2-rGO Field-Effect Transistor as a Platform for Biosensing Applications

The performance of the graphene-based field-effect transistor (FET) as a biosensor is based on the output drain current (Id). In this work, the signal-to-noise ratio (SNR) was investigated to obtain a high-performance device that produces a higher Id value. Using the finite element method, a novel top-gate FET was developed in a three-dimensional (3D) simulation model with the titanium dioxide-reduced graphene oxide (TiO2-rGO) nanocomposite as the transducer material, which acts as a platform for biosensing application. Using the Taguchi mixed-level method in Minitab software (Version 16.1.1), eighteen 3D models were designed based on an orthogonal array L18 (6134), with five factors, and three and six levels. The parameters considered were the channel length, electrode length, electrode width, electrode thickness and electrode type. The device was fabricated using the conventional photolithography patterning technique and the metal lift-off method. The material was synthesised using the modified sol-gel method and spin-coated on top of the device. According to the results of the ANOVA, the channel length contributed the most, with 63.11%, indicating that it was the most significant factor in producing a higher Id value. The optimum condition for the highest Id value was at a channel length of 3 µm and an electrode size of 3 µm × 20 µm, with a thickness of 50 nm for the Ag electrode. The electrical measurement in both the simulation and experiment under optimal conditions showed a similar trend, and the difference between the curves was calculated to be 28.7%. Raman analyses were performed to validate the quality of TiO2-rGO.

Detection of SARS-CoV-2 in Environment: Current Surveillance and Effective Data Management of COVID-19

Since diagnostic laboratories handle large COVID-19 samples, researchers have established laboratory-based assays and developed biosensor prototypes. Both share the same purpose; to ascertain the occurrence of air and surface contaminations by the SARS-CoV-2 virus. However, the biosensors further utilize internet-of-things (IoT) technology to monitor COVID-19 virus contamination, specifically in the diagnostic laboratory setting. The IoT-capable biosensors have great potential to monitor for possible virus contamination. Numerous studies have been done on COVID-19 virus air and surface contamination in the hospital setting. Through reviews, there are abundant reports on the viral transmission of SARS-CoV-2 through droplet infections, person-to-person close contact and fecal-oral transmission. However, studies on environmental conditions need to be better reported. Therefore, this review covers the detection of SARS-CoV-2 in airborne and wastewater samples using biosensors with comprehensive studies in methods and techniques of sampling and sensing (2020 until 2023). Furthermore, the review exposes sensing cases in public health settings. Then, the integration of data management together with biosensors is well explained. Last, the review ended with challenges to having a practical COVID-19 biosensor applied for environmental surveillance samples.

Enhanced resonances by waveguide wrapping of a bulbed microring resonator

A high Q-factor novel bulb design, to the best of our knowledge, inspired by the well-studied pulley microring resonator (MRR), is demonstrated and compared with circle and racetrack MRRs at wavelengths of 1.45-1.65 µm. A wrapping of 60% around the ring showed a three times Q-factor increment (Q=828) compared to a standard circle MRR (Q=206) at a telecom wavelength of 1.55 µm with a fixed ring radius of 2 µm, while further increasing the wrapping at 80% shows a decrease in its Q-factor (Q=454). A comparison of the wavelength dependence of the bulb design with other typical MRR designs suggests that bulb designs are highly sensitive to wavelength and have very high Q-factors at lower wavelengths.

MoS2/h-BN/Graphene Heterostructure and Plasmonic Effect for Self-Powering Photodetector: A Review

A photodetector converts optical signals to detectable electrical signals. Lately, self-powered photodetectors have been widely studied because of their advantages in device miniaturization and low power consumption, which make them preferable in various applications, especially those related to green technology and flexible electronics. Since self-powered photodetectors do not have an external power supply at zero bias, it is important to ensure that the built-in potential in the device produces a sufficiently thick depletion region that efficiently sweeps the carriers across the junction, resulting in detectable electrical signals even at very low-optical power signals. Therefore, two-dimensional (2D) materials are explored as an alternative to silicon-based active regions in the photodetector. In addition, plasmonic effects coupled with self-powered photodetectors will further enhance light absorption and scattering, which contribute to the improvement of the device's photocurrent generation. Hence, this review focuses on the employment of 2D materials such as graphene and molybdenum disulfide (MoS2) with the insertion of hexagonal boron nitride (h-BN) and plasmonic nanoparticles. All these approaches have shown performance improvement of photodetectors for self-powering applications. A comprehensive analysis encompassing 2D material characterization, theoretical and numerical modelling, device physics, fabrication and characterization of photodetectors with graphene/MoS2 and graphene/h-BN/MoS2 heterostructures with plasmonic effect is presented with potential leads to new research opportunities.

First-Principles Studies for Electronic Structure and Optical Properties of Strontium Doped β-Ga2O3

The crystal structure, electron charge density, band structure, density of states, and optical properties of pure and strontium (Sr)-doped β-Ga₂O₃ were studied using the first-principles calculation based on the density functional theory (DFT) within the generalized-gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE). The reason for choosing strontium as a dopant is due to its p-type doping behavior, which is expected to boost the material’s electrical and optical properties and maximize the devices’ efficiency. The structural parameter for pure β-Ga₂O₃ crystal structure is in the monoclinic space group (C2/m), which shows good agreement with the previous studies from experimental work. Bandgap energy from both pure and Sr-doped β-Ga₂O₃ is lower than the experimental bandgap value due to the limitation of DFT, which will ignore the calculation of exchange-correlation potential. To counterbalance the current incompatibilities, the better way to complete the theoretical calculations is to refine the theoretical predictions using the scissor operator’s working principle, according to literature published in the past and present. Therefore, the scissor operator was used to overcome the limitation of DFT. The density of states (DOS) shows the hybridization state of Ga 3d, O 2p, and Sr 5s orbital. The bonding population analysis exhibits the bonding characteristics for both pure and Sr-doped β-Ga₂O₃. The calculated optical properties for the absorption coefficient in Sr doping causes red-shift of the absorption spectrum, thus, strengthening visible light absorption. The reflectivity, refractive index, dielectric function, and loss function were obtained to understand further this novel work on Sr-doped β-Ga₂O₃ from the first-principles calculation.

Facile charge transfer in fibrous PdPt bimetallic nanocube counter electrodes

Enhanced charge transfer is realized in DSSCs that utilize poriferous PdPt bimetallic nanocubes as the counter electrode.

Urea and creatinine detection on nano-laminated gold thin film using Kretschmann-based surface plasmon resonance biosensor

This work investigates the surface plasmon resonance (SPR) response of 50-nm thick nano-laminated gold film using Kretschmann-based biosensing for detection of urea and creatinine in solution of various concentrations (non-enzymatic samples). Comparison was made with the presence of urease and creatininase enzymes in the urea and creatinine solutions (enzymatic samples), respectively. Angular interrogation technique was applied using optical wavelengths of 670 nm and 785 nm. The biosensor detects the presence of urea and creatinine at concentrations ranging from 50–800 mM for urea samples and 10–200 mM for creatinine samples. The purpose of studying the enzymatic sample was mainly to enhance the sensitivity of the sensor towards urea and creatinine in the samples. Upon exposure to 670 nm optical wavelength, the sensitivity of 1.4°/M was detected in non-enzymatic urea samples and 4°/M in non-enzymatic creatinine samples. On the other hand, sensor sensitivity as high as 16.2°/M in urea-urease samples and 10°/M in creatinine-creatininase samples was detected. The enhanced sensitivity possibly attributed to the increase in refractive index of analyte sensing layer due to urea-urease and creatinine-creatininase coupling activity. This work has successfully proved the design and demonstrated a proof-of-concept experiment using a low-cost and easy fabrication of Kretschmann based nano-laminated gold film SPR biosensor for detection of urea and creatinine using urease and creatininase enzymes.

Recent Advances in Shape-Controlled Synthesis of Noble Metal Nanoparticles by Radiolysis Route

This paper focuses on the recent advances on radiolysis-assisted shape-controlled synthesis of noble metal nanostructures. The techniques and protocols for producing desirable shapes of noble metal nanoparticles are discussed through introducing the critical parameters which can influence the nucleation and growth mechanisms. Nucleation rate plays a vital role on the crystallinity of seeds while growth rate of different seeds' facets determines the final shape of resultant nanoparticles. Nucleation and growth rate both can be altered with factors such as absorbed dose, capping agents, and experimental environment condition to control the final shape. Remarkable physical and chemical properties of synthesized noble metal nanoparticles by controlled morphology have been systematically evaluated to fully explore their applications.

An objective assessment of proximal and distal facial nerve exploration during superficial parotidectomy

AIM

This study was undertaken to compare the proximal and distal facial nerve exploration approach during superficial parotidectomy.

MATERIALS AND METHODS

A retrospective analysis of patients who underwent superficial parotidectomy at our center was conducted. Cases were divided into those who underwent superficial parotidectomy using distal facial nerve exploration and those who underwent standard proximal facial nerve exploration. Statistical comparisons of intraoperative blood loss and margin status (negative, focally, positive) were conducted between these two approaches.

RESULTS

A total of 39 patients underwent superficial parotidectomy at our center between 2008 and 2010. The technique used in most of the cases was conventional proximal nerve exploration technique (29 cases). Distal exploration of the buccal branch was undertaken only in 10 cases, on account of difficulty in locating the main trunk intraoperatively due to the presence of postinflammatory fibrosis. The average patient age was 48 years with a female preponderance (67%). Both the techniques consumed almost same average operative time (2.4 hours) and average intraoperative blood loss (68.0 cc vs 25.4 cc) was more in the cases where proximal nerve exploration was resorted (S.E (d) = 0.89). No significant difference in surgical margin status was noticed between the two techniques (P > 0.05).

CONCLUSION

Both the techniques are efficient without compromising the surgical margins, but the average intraoperative blood loss is less in distal facial nerve exploration technique.

Study of bone mineral density in resident doctors working at a teaching hospital

CONTEXT

The erratic lifestyle of resident doctors may affect their serum 25-hydroxy vitamin D [25-(OH)D] levels and bone mineral density (BMD).

AIM

To study BMD and the effect of environmental factors on it in resident doctors.

SETTINGS AND DESIGN

Prospective, cross-sectional study conducted in a tertiary healthcare centre.

MATERIALS AND METHODS

BMD was obtained by dual-energy X-ray absorptiometry and was correlated with various factors including weight, height, body mass index (BMI), sun exposure, physical activity, parathyroid hormone, 25-(OH)D, dietary factors. Statistical Analysis : SPSS software Version 10 (Unpaired t test was used to compare BMD of different groups and Pearson's correlation coefficient was used to calculate correlation).

RESULTS

Two hundred and fourteen apparently healthy resident doctors were enrolled in the study. Based on Caucasian normative data, osteopenia was noted in 104 (59.7%) males and 27 (67.5%) females. Thirty-two (18.39%) males and five (12.5%) females had osteoporosis. The BMD values of males were 0.947+/-0.086, 0.911+/-0.129 and 1.016+/-0.133 at lumbar spine, femur neck and total hip while those in females were 0.981+/-0.092, 0.850+/-0.101 and 0.957+/-0.103 respectively. BMD of our cohort was lesser by 12.5-18.2% and 4.2-14.5% than the Caucasian and available Indian figures, respectively. BMD had significant positive correlation with weight, height, BMI, physical activity, and dietary calcium phosphorus ratio. 25-(OH)D levels were insufficient in 175 (87.5%) subjects but had no correlation with BMD.

CONCLUSIONS

Young healthy resident doctors had significantly lower BMD, contributors being lower BMI, lower height, reduced bioavailability of dietary calcium and inadequate physical activity. Deficiency of vitamin D did not contribute to low BMD.

The value of an acute octreotide suppression test in predicting response to long-term somatostatin analogue therapy in patients with acromegaly

CONTEXT

The usefulness of the acute octreotide test in the selection of patients with acromegaly for chronic somatostatin depot analogues treatment is controversial.

AIMS

To determine the efficacy of acute octreotide suppression test (OST) in predicting response to long-term somatostatin analogue (Octreotide-long-acting repeatable, OCT-LAR) therapy in patients with acromegaly.

SETTINGS AND DESIGN

Prospective study (2006-2007) conducted at a tertiary healthcare centre in western India.

MATERIALS AND METHODS

Sixteen drug-naive patients with active acromegaly (postoperative+/-post radiotherapy) underwent 50 microg subcutaneous OST. Ten patients were treated with OCT-LAR for one year. Remission was defined as a nadir growth hormone (GH) < 1 ng/ml during 75 g oral glucose tolerance test (OGTT) (0, 10, 30, 60, 120, 180 min) and normal age, sex-matched insulin-like growth factor 1 (IGF1) levels.

STATISTICAL ANALYSIS

SPSS Software Version 11 was used for data analysis.

RESULTS

Using GH cutoff.

CONCLUSIONS

Nadir GH < 1 ng/ml following an OST is a useful predictive marker of achieving disease remission with long-term OCT-LAR therapy.

Fractures in the Maxillofacial Region: A Four Year Retrospective Study

INTRODUCTION

The incidence of maxillofacial injuries is on the rise due to motor vehicle accidents and increased incidence of violence in recent times. The aim of this retrospective study was to determine the incidence, aetiology, the pattern of fractures, their management with open reduction and internal fixation (ORIF) and complications, if any.

METHODS

A retrospective analysis of 621 fractures in 361 patients managed by ORIF over a four year period was carried out.

RESULT

The average age of patients was 24.3 years with a male to female ratio of 21.2:1. Panfacial fractures comprised 4.7%, frontal bone fractures 8.9%, orbital fractures 0.7%, naso-orbito-ethmoid complex (NOE) fractures 0.7%, zygomatic complex fractures 23.5%, fracture maxilla 11.5% and mandibular fractures 52.2% of all facial fractures. All the cases were successfully managed by ORIF under general anaesthesia (GA). Complications were noticed in 6.8% of cases in the form of reactive implants in 3.6%, deranged occlusion in 1% and infection at operated site in 1% cases which were managed satisfactorily.

CONCLUSION

The findings of this study reveal sharp annual increase in the number of cases of maxillofacial trauma. Road traffic accidents (RTA) were the commonest cause and the age group most affected was between 20-25 years. ORIF of these fractures was chosen for its obvious advantages of direct anatomical reduction, early return to function and minimal complications.

Autoimmune hypophysitis: a single centre experience

INTRODUCTION

Autoimmune hypophysitis (AH) is a rare primary autoimmune inflammatory disorder involving the pituitary gland.

METHODS

A retrospective analysis of the clinical features and outcome of patients diagnosed with AH between 1988 and 2006, was carried out.

RESULTS

15 patients (14 females and one male) with AH were identified. Three patients presented in the peripartum period. Headache, vomiting and visual field defects, suggestive of an expanding sellar mass, were the most common presenting symptoms (67 percent). The most common deficient hormone was adrenocorticotropic hormone (ACTH) (67 percent), followed by thyroid stimulating hormone (53 percent) and gonadotropins (40 percent). Imaging revealed a definite, enhancing sellar mass in 87 percent of the patients and stalk thickening in 33 percent of the patients. Three patients underwent surgery. On serial monitoring, the sellar mass regressed or disappeared spontaneously without any immunosuppressive treatment in the other ten patients with a definite sellar mass.

CONCLUSION

We report a higher female to male ratio and a lower incidence of peripartum cases in our series. Symptoms of mass effect were the most common presentation, while ACTH was the most commonly-deficient hormone. Surgery was rarely needed, and most patients experienced a spontaneous resolution of the mass.

Prevalence of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is commonly associated with type 2 diabetes mellitus (DM) though its prevalence is not well studied. We conducted a prospective study of prevalence and risk factors of NAFLD in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

204 type 2 DM patients attending an out-patient diabetic clinic underwent abdominal sonography. Ninty of 127 patients with fatty infiltration on ultrasound consented for liver biopsy, clinical and biochemical workup.

RESULTS

Eighty seven percent had NAFLD on histology with 62.6% steatohepatitis and 37.3% fibrosis. Age, duration of diabetes mellitus, degree of glycemic control, body mass index, waist circumference, family history of diabetes mellitus, did not predict the presence or severity of NAFLD or fibrosis. Serum alanine aminostranferase (ALT) and alkaline phosphatase levels, though within normal limits, were significantly higher in patients with steatohepatitis. Prevalence of NASH increased with increase in the components of the metabolic syndrome. Serum AST/ALT ratio were also significantly higher (p-0.049) in patients with severe fibrosis. All patients with severe fibrosis had metabolic syndrome.

CONCLUSIONS

Prevalence of NAFLD and NASH in our cohort of type 2 DM patients is high and increases with multiple components of metabolic syndrome. NASH and advanced fibrosis can occur in diabetic patients without any symptoms, signs or routine laboratory test abnormalities.

Carotid body tumours: three case reports

A carotid body tumour is a rare presentation of an extra-adrenal pheochromocytoma. They commonly present with asymptomatic neck masses, and careful preoperative evaluation is required to find out the functional and vascular status of these tumours. We report three cases of carotid body paraganglioma, their evaluation, management and the final outcome.

Congenital adrenal hyperplasia 11beta-hydroxylase deficiency: two cases managed with bilateral adrenalectomy

This series describes two patients with congenital adrenal hyperplasia due to 11beta-hydroxylase deficiency. The first patient, a ten-year-old with XX genotype, reared as a male, presented with resistant hypokalaemia and hypertension. The second patient, a 23-year-old with XY genotype, presented with bilateral adrenal masses and resistant hypertension. Both the patients were offered bilateral adrenalectomy. These two patients are described with a discussion on the role of bilateral adrenalectomy in the management of difficult cases of congenital adrenal hyperplasia. The association of myelolipoma and testicular rests with this condition is also discussed.

Management of Mandibular Fractures

BACKGROUND

To evaluate the cases of mandibular fractures treated by open reduction and rigid fixation at the Armed Forces Medical College, Pune.

METHODS

Two hundred and thirteen mandibular fractures cases were treated by open reduction and rigid fixation from Jun 1998 to Jun 2006. These were retrospectively analyzed based on the following patient related factors i.e. mode of injury, age and sex distribution, site of injury, associated injuries and surgical treatment.

RESULT

The significant finding was that the most common etiology for fracture mandible was road traffic accidents (RTA), [196 (92%)]. Of the patients who reported, 147 (95.4%) were males in the third decade of life. 96 (45%) patients had parasymphysis fractures, 65 (30.5%) had angle fractures, 33 (15%) subcondylar fractures, 17 (7.9%) body fractures and 2(0.9%) had ramus fracture. Early intervention using open reduction and internal fixation was the protocol followed which resulted in minimum morbidity and complications.

CONCLUSION

As RTA especially two wheelers accidents appeared to be the most common cause of mandibular fractures, use of suitably designed protective head gear (crash helmets) is advisable. Moreover open reduction and rigid internal fixation appears to be the suitable treatment modality in successful treatment of mandibular fractures in reducing morbidity and complications and ensuring early return to normalcy.

Secondary and Delayed Bone Grafting in Alveolar and Anterior Palatal Clefts

BACKGROUND

Surgical repair with suitable bone graft / substitutes plays an important role in rehabilitation of individuals with residual anterior palatal or alveolar defects associated with an oronasal fistula.

METHODS

52 cases were treated by secondary or delayed bone grafting of the alveolar defects in isolation or associated with defects of the anterior palate from July 2002 - Nov 2004. Dimension and the extent of the defects were assessed with the help of radiographs & maxillofacial CT. Cephalometric analysis, presurgical orthodontics and dentofacial orthopedics preceded surgical repair with cancellous graft from the iliac crest, followed by post surgical orthodontics and prosthetic rehabilitation.

RESULT

Satisfactory results were achieved in 49 cases with three cases showing failure of graft acceptance. Postoperative clinical and radiological evaluation for all the patients was done at an interval of one, three and six months. Bone density and trabeculation was comparable to the adjacent bone within six months.

CONCLUSION

Recreating the bony continuity of the maxillary arch followed by orthodontic correction of dental discrepancies achieves a comprehensive orthosurgical correction.

Evaluation of low dose ACTH stimulation test in suspected secondary adrenocortical insufficiency

BACKGROUND

Several studies in the last few years have shown that the standard 250 micro g dose used in ACTH stimulation test may be very high and have suggested that a dose of 1 micro g may be sufficient for evaluating hypothalamo-pituitary adrenal (HPA) axis.

AIMS

To evaluate the role of low dose ACTH stimulation test in patients with suspected Secondary Adrenal Insufficiency (SAI).

SUBJECTS AND METHODS

Thirty-one patients of suspected SAI with a documented pituitary lesion and seven normal healthy controls were included in the study. All the subjects underwent ACTH stimulation test with standard high dose (HD= 250 microg) and low dose (LD= 1 microg) ACTH. Insulin Induced Hypoglycaemia (IIH) test was done in 7 out of 9 patients in whom the results of the two tests were discordant. The cut off for normal HD stimulation test was taken as peak cortisol response > 18 microg/dl and for LD test, either a cortisol response of > 18 microg/dl or an increment of more than 7 micro g/dl over the basal value at any time during the test, on the basis of response observed in controls.

RESULTS

22/31 patients (74%) in SAI group showed concordant results with both tests, whereas nine patients had discordant results. These nine patients showed AI with LD ACTH, but HD ACTH test showed a normal response. In 7 of these 9 patients who underwent IIH, AI was confirmed in 6.

CONCLUSION

The LD ACTH stimulation test seems to be better than HD ACTH stimulation test for evaluating HPA axis in patients with suspected SAI. When basal cortisol is normal, LD ACTH stimulation test detects subtle SAI.

Factor IX gene polymorphisms in Indian population

Hemophilia B is an X-linked, recessive disorder of hemostasis, caused by a defect in coagulation factor IX. To date, several restriction fragment length polymorphisms (RFLPs) have been identified within the gene for human factor IX. The incidence of these RFLPs differs significantly in different populations. In the present study, we analyzed the heterozygosity frequency and the allele frequency of three common intra- and extragenic polymorphic sites of the factor IX gene in Indian population. The main objective was to test the informativeness of two intragenic markers Dde I and Xmn I and one extragenic marker Hha I for carrier detection and prenatal diagnosis. The method used was polymerase chain reaction (PCR) and RFLP, which is economical yet simple to perform. In Indian population Dde I marker showed an informativeness of 69.0% followed by 38.0% for Hha I and 23.0% for Xmn I. The cumulative informativeness of these three markers was found to be 80 to 82%. A comparison of the heterozygosity rates of these three markers with the other ethnic groups showed that Indian population had almost similar pattern with the Caucasians and American blacks but differed significantly from the Orientals including Japanese, Chinese and Malays.

Novel mutations of MYO15A associated with profound deafness in consanguineous families and moderately severe hearing loss in a patient with Smith-Magenis syndrome

Mutations in myosin XVA are responsible for the shaker 2 ( sh2) phenotype in mice and nonsyndromic autosomal recessive profound hearing loss DFNB3 on chromosome 17p11.2. We have ascertained seven families with profound congenital hearing loss from Pakistan and India with evidence of linkage to DFNB3 at 17p11.2. We report three novel homozygous mutations in MYO15A segregating in three of these families. In addition, one hemizygous missense mutation of MYO15A was found in one of eight Smith-Magenis syndrome (del(17)p11.2) patients from North America who had moderately severe sensorineural hearing loss.

Prenatal diagnosis of haemoglobinopathies

BACKGROUND

Haemoglobinopathies constitute a major health problem in the Indian subcontinent. In the absence of any method for achieving complete cure and treatment being expensive, prenatal diagnosis and selective termination of an affected foetus is a feasible option to decrease the disease load. We report our experience with prenatal diagnosis of haemoglobinopathies over a two-and-a-half year period in 257 pregnancies.

METHODS

Amplification refractory mutation system (ARMS) was used to detect beta-thalassaemia, haemoglobin E and sickle cell mutations.

RESULTS

Five mutations in the beta-globin gene which are common in the Indian population were detected in 92.3% of mutant chromosomes, whereas 3.1% of chromosomes carried rare mutations followed by 0.8% haemoglobin E and 0.4% sickle cell mutations. Mutations in 3.3% chromosomes were uncharacterized. The prenatal procedure, carried out early in pregnancy, was a chorionic villus sampling in most cases. A confirmed diagnosis based on ARMS-PCR was given in 241 (93.8%) cases. In 10 cases (3.9%) linkage analysis was required to confirm the foetal status, as mutations in both parents were not identified or the chorionic villus sample carried the single identified mutation. Four families with haemoglobin E-beta thalassaemia and one family with sickle cell disease were also included. Of the study population, 91.25% of the couples had a previous child with haemoglobinopathy, whereas 8.75% of the couples came before the birth of the first affected child.

CONCLUSION

We conclude that ARMS-PCR is a highly sensitive technique for detecting mutations in the beta-globin gene and its efficacy in the prenatal diagnosis of haemoglobinopathies is proven.

Dyslipidemia with particular regard to apolipoprotein profile in association with polycystic ovary syndrome: a study among Indian women

OBJECTIVE

To investigate putative dyslipidemia in women with polycystic ovary syndrome (PCOS) with particular emphasis on specific parameters of atherosclerotic risk, and to assess the independent influence of obesity and hyperandrogenemia on these parameters.

SUBJECTS

Women investigated were among those attending the infertility clinics. Three groups of women were studied: (I) a core study group consisting of oligomenorrhoeic, chronically anovulatory women with or without obesity in whom polycystic ovaries were confirmed through ultrasound evidence, and were established to be the cause of infertility; II) a control group of non-hirsute, non-obese women with regular menstrual cycles; and (III) a group of controls consisting of women with obesity, but with normal ovarian morphology and regular menstrual cycles.

METHODS

All three study groups were investigated for androgen (total testosterone) and lipid-lipoprotein profile, including apolipoproteins, ApoA1 and ApoB. Retrospective analysis of the data was carried out to assess hyperandrogenism in the study group of women with PCOS as well as to investigate changes in the lipid-lipoprotein profile, particularly the measures of cardiovascular risk, ApoA1 and ApoB.

RESULTS

Triglycerides showed a significant increase in the PCOS group compared to controls, whereas HDL-cholesterol as well as HDL-carrying ApoA1 showed a significant decrease (P < .05). Also a significant finding was the decrease in ApoA1/ApoB ratio among the women with PCOS compared to both controls and obese women. A direct negative correlation of this decrease in ApoA1/ApoB ratio with the Body Mass Index was also confirmed in the study. Hyperandrogenemia in terms of significantly raised total testosterone levels was found in 30% of the PCOS women. However, no direct correlation of this increase with changes in lipid-lipoprotein profile could be observed.

CONCLUSION

The study confirms the trend toward dyslipidemia among women with PCOS, particularly in parameters associated with cardiovascular risk. A significant association of obesity rather than raised testosterone with this dyslipidemia was also confirmed by the study.

Autoimmune thyroid disease in Indian children with type 1 diabetes mellitus

The objective of the present study was to determine the prevalence of autoimmune thyroid disease in Indian children with type 1 diabetes mellitus by the assay of antibodies to thyroid peroxidase and thyroglobulin. The study population consisted of 35 children with type 1 diabetes mellitus and 32 healthy age- and sex-matched control children. Thyroid peroxidase antibodies (TPO) were determined by ELISA and thyroglobulin antibodies (TGA) by passive hemagglutination. Thyroid function tests and tests of glycemic control were also performed. These assays were repeated after six months and one year. TPO were observed in 19 (54.3%) patients compared to three (10%) controls, and TGA in 11 (31.4%) patients and none of the controls. Both these observations were statistically significant with p=0.0002 for TPO and 0.0016 for TGA. The prevalence of these antibodies was not different in boys and girls and did not change with the duration of diabetes. All patients who were positive for TGA were also positive for TPO. Thyroid function tests were abnormal in one patient who was found to have Hashimoto's thyroiditis. There is a definite need to screen all diabetic children for thyroid antibodies and carefully follow up those patients in whom these antibodies are positive.

Diagnosis and management of congenital adrenal hyperplasia: clinical, molecular and prenatal aspects

Congenital adrenal hyperplasia (CAH) is the most common cause of female pseudohermaphroditism in Indian children. It is caused by enzymatic defects in the steroidogenic pathway of the adrenal glands and is characterized by impaired cortisol and aldosterone synthesis and overproduction of androgens. The disease usually presents with life-threatening problems and virilization, with long term physical and psychological effects. The clinical and laboratory diagnoses play an important role in deciding the course of treatment, which continues lifelong. To ensure proper growth and development of the patient, optimized disease management and treatment with steroids is required. Often the patient also requires surgical correction. Recent developments in molecular genetics have greatly helped in understanding the pathogenesis of the disease. The gene encoding for steroid 21-hydroxylase, CYP21, is located on the short arm of chromosome 6 in the HLA region and is amplified for genetic diagnosis. Rapid characterization of point mutations is possible using the allele-specific polymerase chain reaction technique in affected children. Counselling, prenatal diagnosis and treatment are recommended in all pregnant women with a positive family history to reduce or eliminate the effects in affected foetuses. This spares the female newborn the consequences of genital ambiguity and problems of gender identity.

Molecular characterization of mutations in Indian children with congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) is the commonest cause of female pseudohermaphroditism. It is most often due to steroid 21-hydroxylase deficiency resulting from mutations in the CYP21 gene. This study was conducted to characterize mutations in the CYP21 gene, determine their frequency and correlate genotype with phenotype in Indian children with CAH. Twenty-eight patients with salt-wasting (SW) or simple-virilizing (SV) forms of the disease as well as parents and siblings were studied. Allele specific PCR was carried out and rapid characterization of six mutations was achieved in 23 patients. Twelve patients were homozygous for the mutations and 11 were heterozygous, of whom eight were compound heterozygotes and three were hemizygotes; no mutation was found in five patients. The homozygosity of the mutations was found to be high in our population. The most common mutation was Ile173Asn (31.8%), followed by intron2 splice (27.2%), Gln319stop (22.7%), gene deletion (15.9%) and Pro31Leu (2.2%). Genotype-phenotype correlations showed that the most frequent mutations in the SW group were intron2 splice and Gln319stop mutations (33.3% each) and Ile173Asn (71.4%) in the SV group.

Factor VIII gene polymorphisms in the Asian Indian population

Little is known about the heterozygous frequency of factor VIII gene markers in the Asian Indian population. The objective of this study was to establish the heterozygous frequency of polymorphic markers within and flanking the factor VIII gene in Indians and identify those most informative for carrier screening and prenatal diagnosis. Factor VIII gene polymorphism analysis at intragenic and extragenic sites was carried out by the polymerase chain reaction (PCR) method and Southern blot procedure. Sixty-three Asian Indian haemophiliacs and their families were screened. A control group of 150 women from nonhaemophilic families were screened for two markers, HindIII and BclI. Among the intragenic markers studied, the HindIII restriction fragment length polymorphism (RFLP) showed the highest heterozygous frequency (0.52) followed by the intron 13 (0.47) and intron 22 (0. 44) short tandem repeats (STRs). Among extragenic markers, TaqI had the highest heterozygous frequency (0.75) followed by BglII (0.54). The intron 22 inversion mutation was observed in eight (40%) of 20 severe cases. In the population studied the most diagnostic polymorphisms were the intragenic markers, intron 22 (70%) STR followed by the intron 13 (52%) STR and HindIII (52%) RFLP, and the TaqI (50%) extragenic marker. Application of HindIII, BclI and the intron 22 dinucleotide repeat combined were diagnostic in 87.2% of haemophilia A families studied.

Infantile-onset leukoencephalopathy with discrepant mild clinical course

Four children characterised by megalencephaly and cerebral leukoencephalopathy with infantile onset, defined on the basis of clinical and neuroimaging findings are reported. The course of the disease is characterised by stabilization of the macrocephaly and slow clinical deterioration. The CT scan findings include supratentorial diffuse hypodensities in the white matter and swelling. The characteristic MRI findings include the discrepant severity in comparison with the clinical picture, diffuse supratentorial white matter abnormalities with subcortical cysts. The basic defect of the disease is unknown. Considering the high rate of consanguinity among the parents and the presence of two affected sibs in one family, an autosomal recessive inheritance is assumed. We report four unrelated cases of this entity.

Fraser-cryptophthalmos syndrome

Fraser or Cryptophthalmos syndrome is a variable syndrome to the extent that cryptophthalmos might not be present in all cases. However, the main features are a "hidden eye", other craniofacial abnormalities, renal abnormalities, syndactyly and abnormal genitalia. It may be classified as isolated cryptophthalmos or cryptophthalmos sequence and cryptophthalmos syndrome. The cryptophthalmos syndrome has an autosomal recessive mode of inheritance. Isolated cryptophthalmos has been reported as an autosomal dominant trait. Prenatal diagnosis is possible using ultrasonography and fetoscopy. We report three cases of cryptophthalmos. One with renal agenesis had cryptophthalmos syndrome and the other two had isolated cryptophthalmos or cryptophthalmos sequence.

I-cell disease (Mucolipidosis II)

I-cell disease (Mucolipidosis II) is one of the lysosomal storage diseases which presents in the neonatal period, and within six months will phenotypically resemble the severe forms of the group of disorders called the "mucopolysaccharidoses" but without mucopolysacchariduria. In Mucolipidosis II, fibrocytes exhibit "abnormal lysosomes". Activities of several lysosomal enzymes are low in fibroblast cultures but high in mucolipidosis II serum. We present a patient with I-cell disease diagnosed on the basis of clinical, radiological and biochemical features. The mother of this child was pregnant and the fetus was also found to be affected.