Replication study identified EFEMP1 association with varicose vein predisposition among Indians

BACKGROUND

Varicose vein is a chronic condition that affects the lower extremities of the human body. Several factors have been implicated in the development of this disease, viz age, gender, weight, height and prolonged standing. Recently, genome-wide studies have identified genetic biomarkers that are associated with varicose veins in different ethnic groups. Such genetic studies are lacking in South Asians specifically in Indians where the prevalence of varicose veins is high, and it is important to replicate these variants in the stated population. The study aimed to replicate the association of genetic variants associated with varicose veins in this target population, which were found to be associated with the other ethnic groups.

METHODOLOGY

The studied cohort is of the Indian population comprising unrelated 104 varicose veins cases and 448 non-varicose vein controls. The samples were genotyped using the Illumina Global Screening Array. Using the genomic data from UK BioBank and 23andMe studied cohorts; eight genetic variants were selected to replicate in our dataset. The allelic association was performed to identify the effective allele and risk was estimated using odds ratio and p-value as level of significance. Multifactor Dimensionality Reduction was used to estimate the cumulative effect of variants in Indians.

RESULT

Variant rs3791679 of EFEMP1 was found to be associated with varicose veins in Indians. After observing the association of the EFEMP1 with varicose veins, we further ensued to identify all genetic variants within EFEMP1 to uncover the additional variants associated with this trait. Interestingly, we identified six new variants of EFEMP1 gene that have shown association. Moreover, the cumulative effect of all associated variations was estimated and the risk was 2.7 times higher in cases than controls whereas independently their effect ranges from 0.37-1.58.

CONCLUSION

This study identifies EFEMP1 as a potential gene related to the risk of varicose veins in Indians. It also highlights that evaluating the maximum number of variants of a gene rather than focusing solely on replicating single variations offers a more comprehensive and nuanced understanding of the genetic factors contributing to a complex trait like varicose veins.

Association of TYRP1 with hypoxia and its correlation with patient outcome in uveal melanoma

PURPOSE

Molecular mechanisms of uveal melanoma development in association with high pigmentation are unclear. Tyrosinase Related Protein (TYRP1) is not only one of the important melanogenesis marker that contributes to melanin synthesis, but can also prevents the melanocyte death. The induction of melanogenesis leads to induction of HIF-1α which can affect the behavior of melanoma cells and its surrounding environment. The aim of our study was to determine the expression of TYRP1 and HIF-1α at the protein and RNA level and determine its prognostic significance.

METHODS

In the present study, the expression of TYRP1 and HIF-1α was investigated on 61 formalin-fixed paraffin-embedded choroidal melanoma samples by immunohistochemistry. Fresh 50 samples were validated by real-time PCR. Results were correlated with clinicopathological parameters and Kaplan-Meier was performed to determine the prognostic significance.

RESULTS

High immunoexpression of TYRP1 and HIF-1α was present in 61 and 54% of patients, respectively. Both TYRP1 and HIF-1α correlated well with high pigmentation and BAP1 (BRCA1 Associated Protein-1) loss (p < 0.05) at IHC level as well as transcriptional level. There was reduced metastatic free survival in patients with necrosis and this was statistically significant (p = 0.010).

CONCLUSION

Our findings indicate that TYRP1 can be used as a potential biomarker in the development of targeted therapy in UM. Further studies on melanogenesis markers associated with TYRP1 could provide us a better understanding in this field.

Constitutive expression of c-REL in uveal melanoma patients: correlation with clinicopathological parameters and patient outcome

PURPOSE

Uveal melanoma (UM) is the most common intraocular cancer with a high mortality rate that requires new research in the field of prevention and treatment. c-REL is a member of the nuclear factor κB (NF-κB) transcription factor family and an emerging regulator of tumorigenesis. Therefore, the objective of the study is to evaluate the constitutive expression of c-REL in uveal melanoma patients and its prognostic significance.

METHODS

Detection of c-REL expression was carried out by immunohistochemistry in all 75 patients, and qRT-PCR performed on 58 fresh cases of uveal melanoma along with IL-6 status. Immunoblot was performed to validate immunohistochemistry results. Expression of c-REL protein correlated with clinicopathological parameters and overall survival of patients.

RESULTS

Immunohistochemistry results revealed nuclear expression of the c-REL protein (56%) in our cases. Out of 75 cases, 31 cases showed nuclear expression, and 11 cases had cytoplasmic expression. qRT-PCR showed upregulation of the REL gene in 56.89% cases at the transcriptional level. There was a statistically significant difference in the overall survival of patients with c-REL nuclear immunopositivity (p = 0.0048). On multivariate analysis, scleral invasion and c-REL nuclear expression found to be an independent prognostic factor (p < 0.05) CONCLUSIONS: To the best of our knowledge, this was the first study reporting the expression of the c-REL protein in uveal melanoma. Strong nuclear immunoexpression of c-Rel suggests NFκB pathway activation which might be involved in the progression of the disease. Differential expression of c-REL protein may be used as an attractive target for the development of anticancer strategies.

0583 Obesity-Associated Sleep Hypoventilation Syndrome and Adverse Post-Operative Bariatric Surgery Outcomes

Introduction

Although obesity hypoventilation syndrome (OHS) is associated with right ventricular dysfunction and increased mortality, its contribution to post-bariatric surgery risk remains unclear due to non-systematic OHS assessments. We hypothesize that patients with obesity-associated sleep hypoventilation (OASH) have increased adverse post-bariatric surgery outcomes than those without.

Methods

Patients undergoing polysomnography (PSG) prior to bariatric surgery at the Cleveland Clinic from 2011-2018 were retrospectively examined. OASH was defined by body mass index (BMI) ≥30kg/m2 and either PSG-based end-tidal CO2 ≥45mmHg or serum bicarbonate ≥27mEq/L. The following were considered individually and as a composite outcome: ICU stay, re-intubation, tracheostomy, discharge disposition or 30-day readmission. All-cause mortality was also examined. Outcomes were compared using two-sample t-test or Wilcoxon rank sum test and Chi-square or Fisher exact test. A multivariable logistic regression model included age, sex, BMI, apnea hypopnea index(AHI) and diabetes to examine OAHS and the composite outcome. All-cause mortality was compared using Kaplan-Meier estimation and hazard ratios from Cox proportional hazards models. SAS software (version 9.4) was used with overall significance level of 0.05.

Results

The sample comprised 1665 patients: age 45.2±12 years, 20.4% male, BMI=48.7±9 kg/m2, and 63.6% Caucasian. OASH prevalence was 68.5%. OAHS patients were older and more likely to be male with higher BMI, AHI and HbA1c. Although some individual outcomes were higher in OASH vs. non-OASH, findings were not statistically significant: re-intubation (1.5%vs.1.3%, p=0.81) and 30-day readmission (13.8% vs.11.3%, p=0.16). The composite outcome remained significantly associated with OAHS in the multivariable model: OR=1.36, 95%CI:1.005,1.845. Mortality was 2% in OASH and not significantly higher than non-OAHS (HR=1.39, 95%CI:0.56,3.42).

Conclusion

In this largest sample to date of systematically phenotyped OASH in patients undergoing bariatric surgery, we identify increased post-operative morbidity in those with OASH. Further study is needed to identify whether peri-operative treatment of OASH improves surgical outcomes.

Support

 

Postoperative pain relief and functional outcome following total knee arthroplasty - a prospective comparative audit of three analgesic regimes

Pain control plays a key role in joint-replacement -surgery. As a surgeon the challenge is to reduce pain to an acceptable level in the post-operative period. The aim of the study was to assess the efficacy of bolus -local anaesthesia, infusion in to the surgical site and nerve blocks with femoral nerve catheter and its functional outcome. A prospective audit of 114 patients undergoing total knee arthroplasty were carried out.The patients were divided in to three groups : Group 1 (n = 27) received a bolus injection of 20 ml 0.25% levobupivacaine + 10 ml 0.25%bupivacaine + adrenaline + 30 ml saline. Group 2 (n = 39) received a bolus injection as on group 1 with 240 ml 0.25% bupivacaine infusion and 5 ml/hour using a Pain Buster pump. Group 3 (n = 48) received 30 ml 0.125% levobupivacaine to femoral (3-in-1) block with 30 ml 0.25% levobupivacaine to -sciatic nerve and introduction of a femoral nerve catheter. All patients were prescribed paracetamol 1 g QDS, Oxycontin 20 mg BD and Ibuprofen post -operatively. Pain was assessed with a Visual Analog Scale (VAS). The incidence of PONV was measured by PONY intensity score. The mean post-op VAS score for Group 3 was 4. The demand of oxynorm and NSAID were minimal in Group 3. The mean in patient stay for Group 3 was 3.1 days. The PONV intensity score was > 50 for 9 (36%) in Group 1, 15 (40%) in Group 2 and 9 (20%) in Group 3. There was loss of 20-30 degrees of flexion movements in Group 3 in the first 4 to 6 days post-op. Our study demonstrated that Regime 3 with the use of nerve blocks and femoral nerve catheter has given the maximum pain relief and good functional outcome following total knee replacement.

Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150-300 parts per billion by weight (ppbw)) and C₂ to C₄ dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles.

KEY POINTS

First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition.

Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150-300 parts per billion by weight (ppbw)) and C₂ to C₄ dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles.

KEY POINTS

First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition.

The effect of total hip and hip resurfacing arthroplasty on vertical ground reaction force and impulse symmetry during a sit-to-stand task

BACKGROUND

The aim of this study was to determine the influence of total hip arthroplasty and hip resurfacing arthroplasty on limb loading symmetry before, and after, hip reconstruction surgery during a sit-to-stand task.

METHODS

Fourteen patients were recruited that were about to receive either a total hip prosthesis (n=7) or a hip resurfacing prosthesis (n=7), as well as matched controls. Patients performed a sit-to-stand movement before, 3 months after, and 12 months after surgery. Peak vertical ground reaction force and impulse were measured for each leg, from which ground reaction force and impulse symmetry ratios were calculated.

FINDINGS

Before surgery, hip resurfacing patients showed a small asymmetry which was not different to normal for ground reaction force (0.88(0.28) vs. 1.00(0.11); p=0.311) or impulse (0.87(0.29) vs. 0.99(0.09); p=0.324) symmetry ratios. Total hip patients offloaded their affected hip by 30% in terms of impulse symmetry ratio (0.71(0.36) vs. 0.99(0.23); p=0.018). At 3 months following surgery asymmetries were seen that were different to normal in both hip resurfacing patients for ground reaction force (0.77(0.16); p=0.007), and total hip patients for ground reaction force (0.70(0.15); p=0.018) and impulse (0.72(0.16); p=0.011) symmetry ratios. By 12 months after surgery total hip patients regained a symmetrical loading pattern for both ground reaction force (0.95(0.06); p=0.676) and impulse (1.00(0.06); p=0.702) symmetry ratios. Hip resurfacing patients, however, performed the task by overloading their operated hip, with impulse symmetry ratio being larger than normal (1.16(0.16); p=0.035).

INTERPRETATION

Physiotherapists should appreciate the need for early recovery of limb loading symmetry as well as subsequent differences in the responses observed with different prostheses.

Phenotypic evaluation of severely damaged ocular surface after reconstruction by cultured limbal epithelial cell transplantation

OBJECTIVE

To report the clinical outcome of autologous cultured limbal epithelial cell transplantation (CLECT) followed by deep anterior lamellar keratoplasty (DALK) in paediatric eyes and to correlate the clinical outcome with the phenotype of rejuvenated corneal epithelium.

METHODS

Four patients with total limbal stem cell deficiency (LSCD) underwent autologous CLECT. Cultivated cell sheets were transplanted onto the damaged ocular surface followed by DALK surgery. Excised corneal buttons were subjected to histopathological analysis. Data recorded included age, sex, laterality, nature of injury, follow-up period, severity of stem cell deficiency, visual acuity, Schirmer's test and impression cytology.

RESULTS

At a mean follow-up period of 19.5 ± 7.4 (range 9-26) months after CLECT, all 4 eyes showed epithelialized and clinically stabilized ocular surface. Manual DALK was performed in all 4 eyes, with a mean follow-up of 9.75 ± 4.5 (range 5-15) months. All eyes exhibited smooth and clear corneal epithelium with improved visual acuity. Excised corneal buttons demonstrated organized corneal epithelial morphology and showed expression of cornea-specific CK3/12 marker.

CONCLUSION

Restoration of severely damaged ocular surface following chemical injury by using 2-stage meticulous approaches offers a new modality for the treatment of severe LSCD. Transplantation of cultivated autologous limbal epithelial cell sheet followed by DALK surgery can efficiently restore the corneal phenotype with improved vision.

Computational Modeling Deduced Three Dimensional Structure of Cry1Ab16 Toxin from Bacillus thuringiensis AC11

The first theoretical structural model of newly reported Cry1Ab16 δ-endotoxin produced by Bacillus thuringiensis AC11 was predicted using homology modeling technique. Cry1Ab16 resembles the Cry1Aa protein structure by sharing a common three domains structure responsible in pore forming and specificity determination along with few structural deviations. The main differences between the two is in the length of loops, absence of α7b, α9a, α10b, α11a and presence of additional β12b, α13 components while α10a is spatially located at downstream position in Cry1Ab16. A better understanding of the 3D structure shall be helpful in the design of domain swapping and mutagenesis experiments aimed at improving toxicity.

Tuberculous lymphadenopathy: a multicentre operational study of 6-month thrice weekly directly observed treatment

SETTING

Eight operational locations for the Revised National Tuberculosis Control Programme in six Indian states.

OBJECTIVE

To assess the 6-month efficacy of an intermittent thrice-weekly directly observed treatment (DOT) regimen for tuberculous peripheral adenopathy and the need for prolongation of treatment to 9 months for non-resolution of lymphadenopathy.

DESIGN

Patients aged >5 years with tuberculous lymphadenopathy were included in the study. Patients were evaluated for resolution at repeat visits following treatment. Those with poor resolution at 6 months were randomised to extended treatment up to 9 months or observation without additional treatment.

RESULTS

Resolution of lymphadenopathy was observed at the end of 6 months in 517/551 (93.8%) patients. There was a significant difference in response among patients with and those without the presence of systemic symptoms. There was no association between treatment response and number, size, site, consistency and matting of lymphadenopathy. No differences in response were seen in the remaining 34 patients with or without extended treatment.

CONCLUSION

The operational efficacy of 6-month thrice-weekly DOT for peripheral tubercular lymphadenopathy was satisfactory. There was no evidence of additional benefits of prolonging treatment to 9 months.

Peculiar reduction of graphene oxide into graphene after diffusion in exponentially growing polyelectrolyte multilayers

In the present work, in situ reduction of graphene oxide (GO) into graphene was preformed, after diffusion in exponentially growing polyelectrolyte multilayers, using sodium citrate as the reducing agent. First, the graphene oxide was obtained by treating a commercial grade of Expanded Graphite (EG). Based on XRD and Raman spectroscopy results, a complete exfoliation of graphene nanopellets down to one layer was achieved during the oxidation process. Secondly, the diffusion of GO was carried out in an exponentially growing polyelectrolyte multilayer film made from poly(diallyldimethylammonium chloride) as the polycation and from poly(acrylic acid) as the polyanion. Electrical conductivity of the GO based films was measured during the reduction process as a function of time. The conductivity reached values of the order of 10(-4) S cm(-1), whereas the pristine polyelectrolyte multilayer was highly insulating (∼10(-8) S cm(-1)). The conductivity also reached a maximal value after about 24 h of reduction and decreased for longer reduction duration. Some tentative explanations for this peculiar finding will be given.

Retinoblastoma

Retinoblastoma is the most common intraocular malignancy in children and one of the very few life-threatening ophthalmic conditions. Genetically, the disease may be heritable or non-heritable. It can have unilateral or bilateral involvement and can present either sporadically or with a positive family history. Leukocoria and strabismus are the most common presentations. Diagnosis is made by indirect ophthalmoscopy aided by imaging techniques. Multidisciplinary management is aimed at saving lives, salvaging the globe and maintaining good vision. The use of neoadjuvant chemotherapy and focal treatments, such as cryotherapy, laser photocoagulation, transpupillary thermotherapy, brachytherapy and periocular chemotherapy, form the mainstay of globe preserving treatment in retinoblastoma. In developing countries, retinoblastoma is unfortunately accompanied by a high mortality rate due to delayed diagnosis made at advanced stages of the disease. Early diagnosis and timely management are vital for a good prognosis.

Evaluating most probable number method to count and isolate viable methylotrophs

Nine different receptacles were tested with the MPN method to determine which receptacle was most reliable and economical for MPN counts. Results showed that 96 well PCR plate were the best vessels for this type of analysis and facilitated the isolation of viable Methylotrophs.

Prevalence of bronchial asthma in school children of 6-13 years of age in Shimla city

BACKGROUND

Asthma is a major public health problem worldwide. However, there is limited data on asthma prevalence among school children in Shimla. The present study was undertaken to determine the prevalence of asthma in Shimla city and also to examine the different factors influencing its occurrence.

METHODS

This was a questionnaire-based study (International Study of Asthma and Allergies in Childhood [ISAAC] protocol) carried out in four randomly selected schools in the city of Shimla. The questionnaire was pre-tested in 50 school children. The age group included in the study was 6-13 years. The questionnaire was distributed to all the children (n = 1136). A response rate of 89.5% was achieved. The socio-economic status was determined on the basis of monthly income (cumulative square root value method). The ISAAC questionnaire was given standard scores. Various factors influencing the prevalence of asthma, such as socio-economic status, history of asthma and other allergic disorders in the family, type of cooking fuel used, history of active and passive smoking were elucidated from the history.

RESULTS

Overall prevalence of asthma in our study was found to be 2.3 percent. Boys had a higher prevalence (3.1%) than girls (1.4%). We found a significant association between asthma prevalence and family history of asthma and other atopic manifestations. There was no significant association of socio-economic factors and exposure to smoking with prevalence of asthma.

CONCLUSION

In the present study, the prevalence of bronchial asthma in school children in the age group of 6-13 years is 2.3 percent.

Abstract 2176: Vascular endothelial growth factor receptor-2 (VEGFR-2) gene variations in bronchioloalveolar cell carcinoma (BAC)

Background VEGF receptor-2 (VEGFR-2) is a key receptor in VEGF-mediated angiogenesis. It plays a significant role in tumor growth and development of metastases. A few studies suggested the angiogenic feature of bronchioalveolar cell carcinoma (BAC), a rare subtype of adenocarcinoma. However the biology of VEGFR-2 in BAC has not been clearly characterized, probably due to its rarity. We sought to determine whether differences in VEGFR-2 expression and microvessel density (MVD) in adenocarcinoma with BAC features (AWBF) might be due to heritable genetic variation in the VEGFR-2 gene. Differences in VEGFR-2 expression and MVD between the pure BAC component of tumor and AWBF, and their comparison with adjacent normal tissue, were also investigated.

Methods DNA was extracted from 46 formalin-fixed paraffin embedded AWBF tissues. Four single-nucleotide polymorphisms (SNPs) and four in/dels were genotyped in all tumors. Tissue microarrays (TMAs) were constructed with tumor tissue (pure BAC component and AWBF component for each tumor) and paired adjacent normal lung tissue. TMAs were stained with anti-VEGFR-2 and anti-phosphorylated-VEGFR-2 (pVEGFR-2) antibodies (scoring: 0-9). MVD was determined by staining with an antibody against CD105, and 95% of the samples had either diffused high or focal high staining.

Results The −271G&gt;A genotype showed a clear gene-dosage effect on pVEGFR-2 expression (GG&gt;GA&gt;AA, p=0.04, linear trend analysis) in AWBF but not in BAC (p&gt;0.1). The −271G&gt;A genotype does not affect the MVD in both BAC and AWBF (linear trend analysis and Kruskal-Wallis, p&gt;0.1). The other SNPs and in/dels did not show any significant association with VEGFR-2, pVEGFR-2, and MVD (p&gt;0.1). VEGFR-2 and pVEGFR-2 expression in tumor (AWBF and pure BAC) was more than 10 times higher the paired normal tissue (p&lt;0.001, Wilcoxon matched pairs test). A trend for higher VEGFR-2 expression in AWBF compared to pure BAC (mean score 4.2 vs. 3.8, p=0.08, Wilcoxon matched pairs test) was observed, while no difference was observed for pVEGFR-2 (p&gt;0.1). For MVD, although the proportion of diffused high staining was higher in BAC (60%) vs. AWBF (47%), this difference is not statistically significant (p&gt;0.1, Fisher's exact test).

Discussion Our study shows that heritable gene variation of −271G&gt;A in VEGFR-2 might reduce the expression of VEGFR-2 in AWBF. This is consistent with the effect of −271G&gt;A in a luciferase assay (Ye et al., AACR 2007), as well as its effect on VEGFR-2 and pVEGFR-2 staining in breast cancer (Cerri et al., SABCS 2009, abstract #904). Although our data are suggestive of different pattern of angiogenesis between pure BAC and AWBF, our sample size is too small to draw any definitive conclusions. Additional studies are ongoing to replicate these findings that will establish the role of genetic variation as a determinant of VEGFR-2 expression in BAC, and the biology of angiogenesis in this rare tumor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2176.

Interactions among peripheral perfusion, cardiac activity, oxygen saturation, thermal profile and body position in growing low birth weight infants

AIMS

To investigate the correlation between the 'perfusion index' (PI) and other commonly used estimates of cutaneous blood flow [heart rate (HR), surface temperatures (ST) and central-to-peripheral thermal gradients (C-P grad)] and to use this new non-invasive tool to compare differences between prone and supine sleep position in low birth weight (LBW) infants.

METHODS

Six-hour continuous recordings of pulse oximetry, cardiac activity and absolute ST from three sites (flank, forearm and leg), along with minute-to-minute assessment of behavioural states were performed in 31 LBW infants. Infants were randomly assigned to the prone or supine position for the first 3 h and then reversed for the second 3 h. PI data were correlated with HR and C-P grad, and compared across sleep positions during quiet sleep (QS) and active sleep (AS).

RESULTS

Perfusion index correlated significantly with HR (r(2) = 0.40) and flank-to-forearm thermal gradient (r(2) = 0.28). In the prone position during QS, infants exhibited higher PI (3.7 +/- 0.9 vs. 3.1 +/- 0.7), HR (158.4 +/- 8.9 vs. 154.1 +/- 8.8 bpm), SpO(2) (95.8 +/- 2.6 vs. 95.2 +/- 2.6%), flank (36.7 +/- 0.4 vs. 36.5 +/- 0.4 degrees C), forearm (36.1 +/- 0.6 vs. 35.5 +/- 0.4 degrees C) and leg (35.4 +/- 0.7 vs. 34.7 +/- 0.7 degrees C) temperatures and narrower flank-to-forearm (0.6 +/- 0.4 vs. 0.9 +/- 0.3 degrees C) and flank-to-leg (1.3 +/- 0.6 vs. 1.8 +/- 0.7 degrees C) gradients, compared to those of the supine position. Similar differences were observed during AS.

CONCLUSION

Perfusion index is a good non-invasive estimate of tissue perfusion. Prone sleeping position is associated with a higher PI, possibly reflecting thermoregulatory adjustments in cardiovascular control. The effects of these position-related changes may have important implications for the increased risk for sudden infant death syndrome in prone position.