The effect of COVID-19 on pain control in patients with a neurostimulator in situ- a retrospective study

BACKGROUND

De-novo chronic neuropathic pain following COVID-19 is widely recognised. However, there are currently no published studies investigating the effect of SARS-CoV-2 infection on patients with pre-existing neuropathic pain who have required spinal cord stimulator (SCS) implantation. Here, the authors aimed to analyse outcomes in their institution's patients who had spinal cord stimulator (SCS) implantation or revision procedures to the system over a 5-year period. Specifically, the short-term and long-term outcomes of patients who contracted COVID-19 during the follow-up period were compared to the control group of patients who did not.

METHOD

Patients included in this study had spinal cord stimulator implantation (de-novo and revision procedures) between 1 January 2017 and 31 January 2022, for neuropathic pain of any aetiology. Patients deemed eligible for the study were invited to participate in a telephone survey through which clinical outcome data were collected. Pain scores were assessed with a modified form of the Brief Pain Inventory (BPI).

RESULTS

Of 91 patients, 48 (52.7%) had contracted COVID-19 by the time of the survey. Patients who contracted COVID-19 had significantly worse BPI scores in the 'Least pain' domain following their infection and at time of the survey, when compared to their score 6 months after the operation. 22.9% (n = 11) of the patients who contracted COVID-19 experienced a change in their symptoms following their infection. Within this sub-group, there was a statistically significant deterioration in BPI scores in 10/11 domains following their infection and in 2/11 domains at time of the survey. Worsening severity of COVID-19 symptoms was not associated with worse BPI scores.

CONCLUSIONS

Infection with SARS-CoV-2, in a significant proportion of patients with an SCS in situ, causes at least a transient deterioration in pain control. Further prospective multicentre studies are indicated to establish the prevalence of this phenomenon.

Retrospective Review of Surgical Site Infections after Endoscopic Endonasal Sellar and Parasellar Surgery: Multicenter Quality Data from the North American Skull Base Society

Introduction  Transnasal access to the anterior skull base provides a minimally invasive approach for sellar and parasellar masses compared with its open counterparts. The unique microbiome of the sinonasal mucosa provides distinct challenges not encountered with other cranial approaches. The use of antibiotics in these cases has not been standardized, and data remain scarce regarding infectious outcomes. Methods  We conducted a multicenter retrospective analysis of shared quality data points for the endoscopic endonasal approach (EEA) for pituitary adenomas, along with other sellar and parasellar region masses that were included by participating institutions. Patient and operative characteristics, perioperative and postoperative antibiotic regimens and their durations, intraoperative and postoperative cerebrospinal fluid leak, and onset of postoperative meningitis and sinusitis were compared. Results  Fifteen institutions participated and provided 6 consecutive months' worth of case data. Five hundred ninety-three cases were included in the study, of which 564 were pituitary adenomectomies. The incidences of postoperative meningitis and sinusitis were low (0.67 and 2.87% for all pathologies, respectively; 0.35% meningitis for pituitary adenomas) and did not correlate with any specific antibiotic regimen. Immunocompromised status posed an increased odds of meningitis in pituitary adenomectomies (28.6, 95% confidence interval [1.72-474.4]). Conclusions  The results show no clear benefit to postoperative antimicrobial use in EEA, with further larger studies needed.

Human erythrocyte surface fucose expression increases with age and hyperglycemia

Background: Reactive oxygen species and other free radicals, together with glucose and its metabolites are believed to play important roles in the aging process. The carbohydrate components of glycosylated proteins are important in mediating cell-cell interactions and a role has been suggested for them in the aging process. Erythrocytes are critical cells in the human body, heavily glycosylated and relatively easily available and so are good candidates to yield insights into how patterns of glycosylation change with age and disease. It has been claimed, based on a periodic acid Schiff assay, that human aging is associated with a decline of erythrocyte surface sialic acids. Plant lectins allow for more specific assays for glycans, including determining the linkage of sialic acids and analysis of single cells by flow cytometry. Methods: Plant lectins, including Maackia amurensis lectin II (MAL), binding to α-2,3 linked sialic acids and Sambucus nigra (SNA), α-2,6 sialic acids, were used in flow cytometry and western blot of erythrocyte surface membrane. N-glycomics mass spectrometry determines glycan structures. Donors varying in age and hyperglycemia, as indicated by HbA1c were analysed. Results: Erythrocyte surface sialic acids have no significant associations with donor age. A combination of storage and cellular aging produces a specific loss of α-2,6 sialic acids. By contrast, erythrocyte surface terminal fucoses increase significantly with donor age. In order to determine which aspects of aging are important in determining this change, we investigated whether this novel human aging biomarker is associated with higher plasma glucose values, assessed by glycated hemoglobin (HbA1c) and reactive oxygen species (ROS) generation. Fucose levels were associated with HbA1c levels, but not ROS generation. Conclusion: Our study identifies novel glycan-based biomarkers for human aging and disease. The simplicity of lectin-based assays provide an attractive cellular tool to study aging and disease processes.

Comparison of pulmonary vein sizing by transesophageal echocardiogram and by direct angiogram

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein (PV) anatomy and sizing is important to know before performing PV isolation. This information is conventionally obtained by angiography or by CT scan.

Aim

We undertook this study to identify and measure the PVs during TEE studies and validate these against angiography.

Method

17 consecutive patients due to undergo PV isolation for paroxysmal atrial fibrillation were analysed. Using TEE, the PVs were visualised (Upper panel) as follows:  i) From the mid-esophageal four chamber view, the chamber probe was turned to the right at 110-130º for the bicaval view, where the RSPV was seen entering the left atrium adjacent to the SVC. ii) At 0º the SVC was imaged in its short axis, and the probe advanced till the interatrial septum was seen. The angle was changed to 30º to visualise the right inferior PV (RIPV). iii) From the two chamber view (70-90º), the probe was turned to the left and withdrawn to display the left superior PV (LSPV) entering the left atrium parallel to the appendage.iv) Keeping the LSPV in focus, the angle was changed to 135º and the probe advanced till the AV groove, where the left inferior PV (LIPV) was visualised. After transseptal puncture, each PV was cannulated. The PV angiograms were performed in several projections to obtain the best PV profile (lower panel). Using electronic callipers, each PV was measured within 1 cm of its entry into the left atrium, after having received all tributaries. Those PVs were considered for analysis which were measured by both TEE and angiography. The paired ‘T’ test was used to compare the PV diameters by TEE and angiography and the Bland Altman analysis was done to see the level of agreement.

Results

Of a total of 68 PVs, 62 could be adequately visualised by TEE and 50 by angiography. These 50 PVs were measured using both methods. The diameters of the PVs measured by TEE and angiography were not statistically different by the paired t test; LSPV14 ± 1.8 mm v/s 14.4 ± 2.1 mm; RSPV 13 ± 1.8 mm v/s 14.6 ± 3.5 mm; LIPV 11.9 ± 2.1 vs 13.2 ± 2.8 mm and RIPV 10.5 ± 2.7 vs 12.1 ± 2.9 mm. Bland Altman analysis showed most PV sizes estimated by TEE and angiography lay within limits of agreement.

Conclusions

A majority of PVs can be visualised by TEE using a defined protocol. TEE is a good technique to visualise and assess the size of PVs, avoiding the need for contrast medium and radiation.

Abstract Figure. TEE and angiographic images of PVs

Is the right ventricular function affected by permanent pacemaker?

Funding Acknowledgements

Type of funding sources: None.

Background

The effect of right ventricular (RV) pacing on left ventricular (LV) function has been extensively evaluated, and so has the effect of the RV pacing lead on tricuspid valve function. However, the effects on RV function per se have not been evaluated systematically.

Purpose

We aimed to assess the RV dimensions and RV function six months after dual chamber pacemaker implantation

performed for atrioventricular (AV) block by detailed echocardiography, including three-dimensional (3D) echocardiography.

Method

All adult patients undergoing dual chamber pacemaker from January 2018 to March 2019 for symptomatic AV block with a structurally normal heart were included in the study. They underwent pre-procedure detailed echocardiography specifically directed at measuring RV dimensions and function [including 3D RV ejection fraction (EF)] and a repeat detailed echocardiogram at six-month follow-up, by the same echocardiographer. The echocardiographic parameters at baseline and after six-month follow-up were compared.

Results

All patients had more than 75% ventricular pacing in these six months. At six-month follow-up, there was no significant change in LVEF, while there was a mild decrease in RVEF as outlined in the Table 1. While there was some overlap between RVEF range of values at baseline and after six months, 23 (38.3%) patients showed a drop in RVEF by >5%.

Conclusion

Our study shows a change in several RV function parameters in a majority of patients six months after

pacemaker implantation for AV block.

RV Function at six month follow-up Parameters Pre-procedure Six-Month Follow-up p value (Paired t-test) PASP (mm Hg) 20.2 ± 1.3 26.1 ± 12.2 <0.001 FAC (%) 42.6 ± 3.4 39.4 ± 6 <0.001 TAPSE (mm) 18.4 ±3.8 15.6 ± 4.7 <0.001 RIMP 0.66 ± 0.09 0.61 ± 0.11 0.003 RV E/E’ 9.4 ± 2.1 7.7 ± 2.1 <0.001 RV S’ 13.6 ± 2.4 10.7 ± 2.4 <0.001 RVEF % [By 3D Echocardiography] 47.7± 5.1 44.9 ± 7.4 <0.001 TR Jet Area (cm2) 0.03 ± 0.26 0.55 ± 0.96 <0.001 RV= Right Ventricle; RA= Right Atrium; RVOT = Right Ventricular Outflow Tract; PASP = Pulmonary Artery Systolic Pressure; FAC= Fractional Area Change; TAPSE= Tricuspid Annular Plane Systolic Excursion; RIMP = Right Ventricular Index of Myocardial Performance; TR = Tricuspid Regurgitation S’ = Peak Systolic Annular Velocity; RVEF = Right Ventricular Ejection Fraction; 3D = Three Dimensional Abstract Figure. Change in RVEF in 6 months

High-resolution optical microscopy for characterising microstructural deformation in microtensile testing

Imaging surface deformation of a coupon specimen in microtensile testing with an optical microscope presents challenges due to the narrow depth of field (DoF) of optical microscopes. Materials being heterogeneous at microscopic length scale, the sample surface deforms into a complex 3D surface texture, evolving continuously as the loading increases. Because of the narrow DoF, the region that is in focus within the field of view (FoV) decreases substantially in size with the increasing out-of-plane heterogeneous deformation. To address this challenge, a method based on image blending and stabilisation of the captured image frames is proposed. Image blending combines the partial regions that are in focus from a set of successive image frames captured at different working distances from the object surface plane to construct a single image that has a large part of the FoV in focus. The blended images are then obtained at different levels of macroscopic strains, that is the global homogeneous strain, in order to characterise the evolution of the heterogeneous deformation. The image stabilisation removes any misalignments of the blended images by spatially realigning them choosing a common feature as a reference point. The validation of the proposed method with conventionally and additively manufactured stainless steel 316L (SS 316L) specimens demonstrates excellent improvement in image quality. Almost 100% of the FoV is maintained in focus regardless of the amount of out-of-plane heterogeneous deformation caused during tensile testing, which is quite remarkable for optical microscopy imaging. Consequently, the blended and stabilised images enhanced the accuracy of digital image correlation (DIC). Time-lapse videos of the deformation generated using these images captured the evolution of the slip bands and their transmission through twinning boundaries in the stainless steel microstructure. Overall, this study demonstrates the feasibility of using image-processing techniques to advance optical microscopy to image complex 3D surfaces evolving with time.

The Bispectral Index and Induced Hypothermia— Electrocerebral Silence at an Unusually High Temperature

The optimal temperature for deep hypothermic circulatory arrest remains undefined. We present a case in which Bispectral Index monitoring during hypothermic cardiopulmonary bypass showed electrocerebral silence at a higher temperature than previously reported. Bispectral Index monitoring may be a potentially useful tool in surgery employing deep hypothermic circulatory arrest.

Postoperative seizures in meningioma patients: improving patient selection for antiepileptic drug therapy

Background

Epilepsy is a major cause of morbidity and mortality in meningioma patients. The aims of this study were to determine which factors predispose meningioma patients to developing perioperative seizures and to understand the impact of antiepileptic drugs.

Methods

Patients treated for a histologically-confirmed intracranial meningioma at the authors’ institution between 2010 and 2015 were retrospectively examined. Clinical and imaging data were assessed. Multivariate analysis was performed using binary logistic regression. The effect of antiepileptic treatment was assessed using survival analysis.

Results

Two hundred and eighty-three patients met the selection criteria; seizures were present in 68 preoperatively (24%) and in 48 patients (17%) following surgery. Of the 68 with preoperative seizures, 19 continued to have them, whereas de-novo seizures arose postoperatively in 29 seizure-naïve patients. Risk factors of postoperative seizures were convexity location (OR 2.05 [95% CI 1.07–3.98], p = 0.030), fronto-parietal location (OR 4.42 [95% CI 1.49–13.16], p = 0.007) and preoperative seizures (OR 2.65 [95% CI 1.37–5.24], p = 0.005). The two locations, in addition to the presence of midline shift on preoperative imaging (OR 4.15 [95% CI 1.54–11.24], p = 0.005), were significantly correlated with postoperative seizures in seizure-naïve patients. Antiepileptic treatment in patients with those risk factors reduced the possibility of seizures at any time point within the 1st year postoperatively by approximately 40%, although this did not meet statistical significance.

Conclusion

Prophylactic antiepileptic treatment might be warranted in seizure-naïve meningioma patients with ≥ 1 risk factor. High-quality randomised controlled trials are required to verify those factors and to define the role of antiepileptics in meningioma practice.

The association of postoperative pulmonary complications in 109,360 patients with pressure-controlled or volume-controlled ventilation

We thought that the rate of postoperative pulmonary complications might be higher after pressure-controlled ventilation than after volume-controlled ventilation. We analysed peri-operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure-controlled ventilation, odds ratio (95%CI) 1.29 (1.21-1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure-controlled ventilation compared with volume-controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg^-1 vs. 1.23 (1.11) ml.kg^-1 , p < 0.001; and 3.91 (3.47) cmH₂ O vs. 3.40 (2.69) cmH₂ O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at positive end-expiratory pressures < 5 cmH₂ O was 1.40 (1.26-1.55) and 1.20 (1.11-1.31) when ≥ 5 cmH₂ O, both p < 0.001, a relative risk ratio of 1.17 (1.03-1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at driving pressures of < 19 cmH₂ O was 1.37 (1.27-1.48), p < 0.001, and 1.16 (1.04-1.30) when ≥ 19 cmH₂ O, p = 0.011, a relative risk ratio of 1.18 (1.07-1.30), p = 0.016. Our data support volume-controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.

Mice lacking the chromodomain helicase DNA-binding 5 chromatin remodeler display autism-like characteristics

Although autism spectrum disorders (ASDs) share a core set of nosological features, they exhibit substantial genetic heterogeneity. A parsimonious hypothesis posits that dysregulated epigenetic mechanisms represent common pathways in the etiology of ASDs. To investigate this hypothesis, we generated a novel mouse model resulting from brain-specific deletion of chromodomain helicase DNA-binding 5 (Chd5), a chromatin remodeling protein known to regulate neuronal differentiation and a member of a gene family strongly implicated in ASDs. RNA sequencing of Chd5-/- mouse forebrain tissue revealed a preponderance of changes in expression of genes important in cellular development and signaling, sociocommunicative behavior and ASDs. Pyramidal neurons cultured from Chd5-/- cortex displayed alterations in dendritic morphology. Paralleling ASD nosology, Chd5-/- mice exhibited abnormal sociocommunicative behavior and a strong preference for familiarity. Chd5-/- mice further showed deficits in responding to the distress of a conspecific, a mouse homolog of empathy. Thus, dysregulated chromatin remodeling produces a pattern of transcriptional, neuronal and behavioral effects consistent with the presentation of ASDs.

Predictive value of serum actin-free Gc-globulin for complications and outcome in acute liver failure

This prospective study was designed to evaluate whether early changes in actin-free Gc-globulin levels were associated with complications and outcomes and to identify factors associated with persistent low actin-free Gc-globulin levels in acute liver failure (ALF). Thirty-two consecutive ALF patients admitted from October 2011 to December 2012 were followed up until death or complete recovery. All had serum actin-free Gc-globulin estimation at admission and at day three or expiry. Logistic regression analysis was performed to identify independent predictors of mortality. A receiver operating characteristic curve analysis was also performed. Nonsurvivors had significantly lower median actin-free Gc-globulin levels than survivors (87.32 vs 180 mg/L; P < 0.001). A receiver operating characteristic curve analysis revealed an area under curve (AUC) of 0.771 and showed that serum actin-free Gc-globulin level of ≤124 mg/L would predict mortality with 92% sensitivity and 71.4% specificity. Patients with lower serum actin-free Gc-globulin levels and decreasing trend in serum actin-free Gc-globulin levels were found to have more mortality and developed more complications. Logistic regression analysis showed that serum actin-free Gc-globulin, total leucocyte count and serum creatinine at admission were independent predictors of mortality. Incorporating these variables, a score predicting mortality risk at admission was derived. The scoring system was compared to MELD score and King's College Criteria as individual predictor of mortality. Serum actin-free Gc-globulin level at presentation is predictive of outcome and can be used for risk stratification. Its persistent low-level predicts mortality and is correlated with various complications.

4-N-pyridin-2-yl-benzamide nanotubes compatible with mouse stem cell and oral delivery in Drosophila

p-aminobenzoic acid (PABA), a structural moiety of many commercial drugs, is self-assembled with linker alkyl side chains to form tubular nanostructures. The tubes exhibited fluorescence either intrinsic or from fluorescent molecules embedded in the wall during self-assembly. Uptake and inter-cellular delivery of the conjugated nanotubes in human cancer cells and in mouse embryonic stem cells were demonstrated by fluorescence imaging and flow cytometry. Biocompatibility, cytotoxicity and clearance were monitored both ex vivo in mouse multipotent embryonic stem cells and in vivo in adult Drosophila. Accumulation of nanotubes had no adverse effects and abnormalities on stem cell morphology and proliferation rate. A distinct distribution of two separate nanotubes in various internal organs of Drosophila interprets that accumulation of nanomaterials might be interdependent on the side chain modifications and physiological settings of cell or tissue types. Unlike carbon nanomaterials, exposure of PABA nanotubes does not produce any hazards including locomotion defects and mortality of adult flies. Despite differential uptake and clearance from multiple live tissues, the use of self-assembled nanotubes can add new dimensions and scope to the development of dual-purpose oral carriers for the fulfilment of many biological promises.

Cross-referral between HIV counselling and testing centres and smear microscopy centres in Tamil Nadu

BACKGROUND

The combined tuberculosis and human immunodeficiency virus (TB-HIV) epidemic demands effective and urgent action.

OBJECTIVE

To assess the effectiveness of the system of referral of TB suspects from the integrated HIV counselling and testing centres (ICTCs) to the designated microscopy centres (DMCs) in Tamil Nadu, and to identify reasons for dropping out.

DESIGN

ICTC counsellors identified TB suspects among clients (excluding pregnant women and children) in six districts of Tamil Nadu in 2007 and referred them to DMCs, irrespective of their HIV status. From the records at ICTCs and DMCs, we collected information on the number of referrals to the DMCs, TB suspects attending DMCs and smear-positive TB cases with or without HIV. Clients who did not attend the DMCs were interviewed to elicit reasons for dropping out.

RESULTS

Of 18329 clients counselled, 1065 (6%) were identified as TB suspects and referred to DMCs. Of these, 888 (83%) attended and 177 (17%) dropped out; 81% of the drop-outs were interviewed. Reasons for dropping out were multiple: 51% were due to the health system, 62% due to the disease and 62% due to personal reasons. Twelve per cent of DMC attendees were smear-positive.

CONCLUSION

The ICTC-to-DMC referral system makes a significant contribution to the detection of TB cases. Reasons for dropping out were multiple, but are correctable. This study also probes into current policies on programme coordination and recommends strategies for strengthening the collaboration between the TB and HIV programmes.

Characterization of a retrotransposon-like element from Entamoeba histolytica

The protozoan parasite Entamoeba histolytica is the causative agent of amoebiasis. The genome organization of this organism is not well understood. We had earlier reported the presence of a multicopy sequence, HMc, in E. histolytica. Subsequent analysis showed that HMc is a member of a retrotransposon family that we have named the E. histolytica retrotransposon-like element (EhRLE). Four other members of this family have been characterized. The EhRLE family is distributed across all chromosomes of the parasite. There are 140 copies, which show minor sequence variation with respect to one another (2--4% from the consensus sequence). From a sequence analysis of five members of the EhRLE family, the complete EhRLE unit is estimated to be 4086 bp in length. It has a 27-mer inverted repeat at its ends. A pairwise comparison with sequences in the database showed a highly significant match of a part of EhRLE with reverse transcriptases (RT), especially those encoded by non-long terminal repeat retrotransposons. There are stop codons in all the five EhRLEs, but a continuous open reading frame of 464 amino acids could be reconstructed by comparing the sequences of several EhRLEs. The reconstructed sequence showed a much better identity with RT as compared with any of the original EhRLE sequences. The non-pathogenic species, Entamoeba dispar, also contains this element, with 85% sequence identity with EhRLE. The data suggest that EhRLE may be a retrotransposon, but many of its members are probably nonfunctional due to the accumulation of mutations.

The genome of Entamoeba histolytica

Estimation of genome size of Entamoeba histolytica by different methods has failed to give comparable values due to the inherent complexities of the organism, such as the uncertain level of ploidy, presence of multinucleated cells and a poorly demarcated cell division cycle. The genome of E. histolytica has a low G+C content (22.4%), and is composed of both linear chromosomes and a number of circular plasmid-like molecules. The rRNA genes are located exclusively on some of the circular DNAs. Karyotype analysis by pulsed field gel electrophoresis suggests the presence of 14 conserved linkage groups and an extensive size variation between homologous chromosomes from different isolates. Several repeat families have been identified, some of which have been shown to be present in all the electrophoretically separated chromosomes. The typical nucleosomal structure has not been demonstrated, though most of the histone genes have been identified. Most Entamoeba genes lack introns, have short 3' and 5' untranslated regions, and are tightly packed. Promoter analysis revealed the presence of three conserved motifs and several upstream regulatory elements. Unlike typical eukaryotes, the transcription of protein coding genes is alpha-amanitin resistant. Expressed Sequence Tag analysis has identified a group of highly abundant polyadenylated RNAs which are unlikely to be translated. The Expressed Sequence Tag approach has also helped identify several important genes which encode proteins that may be involved in different biochemical pathways, signal transduction mechanisms and organellar functions.

Lack of a chromosomal copy of the circular rDNA plasmid of Entamoeba histolytica

A number of small circular DNAs constitute a part of the genome of Entamoeba histolytica. Among them, the 24.5 kb circular DNA encoding rRNA (EhR1) is the most abundant. Pulsed field gel electrophoresis was used to determine if a chromosomal copy of EhR1 exists and what fraction of the total genome is circular. The results show that the chromosomes of E. histolytica are linear, and that no copy of EhR1 could be detected in any of the linear chromosomes.

Finite Element Simulation of Chip Formation and Comparison with Machining Experiment

This paper presents a finite element model of orthogonal machining by using a 2-node link element to simulate chip separation. The chip and workpiece are connected by these link elements along a predefined separation line. The chip separation will be initiated when the distance between the leading node and the tool edge is equal to or smaller than a given value. Consequently, as the tool advances, these link elements will be separated one by one resulting in the formation of the chip and the machined surface. Work material behavior is described by true stress-strain curves for a 0–3 strain range. The chip-tool interaction is modeled as sliding/sticking. In the sliding region a constant coefficient of friction is employed and in the sticking region the shear strength of the workpiece is used. Comparison between simulated and experimental results for machining 70/30 brass and OFHC copper shows a maximum difference of 20 percent, which is acceptable considering the assumptions and the approximations made in the analysis.

Increased activity of interleukin-6 but not tumor necrosis factor-alpha in lung lavage of premature infants is associated with the development of bronchopulmonary dysplasia

Although considerable evidence suggests that bronchopulmonary dysplasia (BPD) is the result of prolonged inflammation and impaired healing of the immature lung, the mediators that regulate inflammation in neonatal lung injury have not been completely elucidated. We examined whether the cytokines IL-6 and tumor necrosis factor-alpha (TNF) interact to modulate a cascade of cell-cell signaling events involved in inflammation contributing to the development of BPD. To determine the relative activities of these cytokines in neonatal lung injury, lung lavage samples were serially obtained from 1 to 28 d from 11 infants with self-limited respiratory distress syndrome (RDS), 19 infants with evolving BPD, and 10 control infants ventilated for nonpulmonary reasons. On the first day of life, there were no differences in antigenic IL-6 concentrations in lavage fluids among the BPD, RDS, and control groups, but IL-6 activity determined by the 7TD1 proliferation assay was 15-fold and 6.6-fold higher in lung lavage of infants who developed BPD compared with activities in lavage from control and RDS infants, respectively (control, 49.4 +/- 17.6; RDS, 117.3 +/- 59.6; BPD, 779.5 +/- 212.6 x 10(3) hybridoma units/L, mean +/- SEM, p = 0.02). This suggests that pathways for inactivating or inhibiting IL-6 that may be present in the lungs of RDS and control infants may be deficient in BPD infants. IL-6 activity remained elevated in lavage of BPD infants for the first 2 wk and declined to low levels by d 28.(ABSTRACT TRUNCATED AT 250 WORDS)

Jatamols A and B: Sesquiterpenoids of Nardostachys jatamansi Roots1

From the roots and rhizomes of NARDOSTACHYS JATAMANSI, two new eudesmanes jatamols A and B were isolated, and their structures were determined by spectral analysis and chemical evidence.

Comparison of measurement of glomerular filtration rate by single sample, plasma disappearance slope/intercept and other methods

Various in vitro methods employing radioactive indicators have been presented for the determination of glomerular filtration rate (GFR) including slope/intercept (S/I) and single sample (SS) methods. The S/I technique utilizes the analysis of the slope of a certain segment of the plasma disappearance curve of a suitable radioactive indicator and its intercept on the y axis. The SS method is based on the theoretical volumes of distribution derived from a single plasma concentration at some specific time after intravenous injection of the indicator. Using GFRs estimated from the compartmental analysis of the entire plasma disappearance curve as a reference standard, we have compared the errors of GFR estimation calculated from 12 S/I methods, 3 SS methods and 2 techniques in which original formulae were derived. The errors of the SS method of Tauxe et al. gave the lowest standard error of estimate (Sy X x) of all the methods. The S/I methods gave lowest errors when sampling times were taken between 60 min and 240 min. Almost all the errors observed here were significantly less than those observed using scintillation camera techniques. The SS method seems to be the method of choice for estimation of GFR by single injection techniques. The use of the scintillation camera in conjunction with the SS technique would provide a useful right to left ratio so that individual kidney GFR could be calculated.

Single-sample method for the estimation of glomerular filtration rate in children

A method for the determination of the glomerular filtration rate (GFR) in children which involves the use of a single-plasma sample (SPS) after the injection of a radioactive indicator such as radioiodine labeled diatrizoate (Hypaque) has been developed. This is analogous to previously published SPS techniques of effective renal plasma flow (ERPF) in adults and children and GFR SPS techniques in adults. As a reference standard, GFR has been calculated from compartment analysis of injected radiopharmaceuticals (Sapirstein Method). Theoretical volumes of distribution were calculated at various times after injection (Vt) by dividing the total injected counts (I) by the plasma concentration (Ct) expressed in liters, determined by counting an aliquot of plasma in a well type scintillation counter. Errors of predicting GFR from the various Vt values were determined as the standard error of estimate (Sy.x) in ml/min. They were found to be relatively high early after injection and to fall to a nadir of 3.9 ml/min at 91 min. The Sy.x Vt relationship was examined in linear, quadratic, and exponential form, but the simpler linear relationship was found to yield the lowest error. Other data calculated from the compartment analysis of the reference plasma disappearance curves are presented, but at this time have apparently little clinical relevance.

Physalindicanols, New Biogenetic Precursors of C28-Steroidal Lactones from Physalis minima var. indica

The structures of two isomeric C (28)-sterols isolated from PHYSALIS MINIMA Linn. var. INDICA were elucidated as ergosta-5,25-dien-3beta,24zeta,-diol and ergosta-5,24(28)-dien-3beta,25-diol on the basis of detailed spectral analysis. The isolated sterols are regarded as precursors in the elaboration of complex C (28)-steroidal lactones, native in this plant and related species.