Proliferation Saturation Index to Simulate Adaptive Radiation Fractionation in HPV-Associated Oropharyngeal Cancer

PURPOSE/OBJECTIVE(S)

In current clinical practice for fractionated radiotherapy (RT) patients receive a fixed fractionation protocol throughout radiation course. Radiation oncology has not yet moved toward adaptive fractionation to change RT fractionation based on individual patients' response dynamics. We have previously introduced a novel mathematical and imaging biomarker, proliferation saturation index (PSI), to simulate and evaluate tumor volume dynamics during therapy. Robust tumor volume reduction was associated with lower PSI, and PSI has been utilized to select fractionation schedules for the first mathematical model informed clinical trial. Here we simulate the possibility of adapting the selection of RT fractionation on a week-by-week basis by utilizing a dynamic weekly estimation of PSI.

MATERIALS/METHODS

We generated a cohort of in silico patients by sampling from distributions of PSI, radiosensitivity, and growth rate parameters. These distributions were by pre-treatment and on-treatment tumor volume dynamics from a prospective clinical trial (NCT03656133), where 49 HPV+ OPC patients were treated with either 2 Gy daily fractions up to a total of 70 Gy if PS<0.75, or hyperfractionation at 1.2 Gy b.i.d. up to a total of 66 Gy for patients with PSI ≥ 0.75. We then simulated standard (2 Gy q.d.) and hyperfractionated (1.2 Gy b.i.d) for 1-8 weeks of RT to build a library of response dynamics for the different parameter combinations and treatment durations. This library was then used to estimate optimal adaptive fractionation schedules for the in silico patients that maximized tumor volume reduction and minimized total RT dose.

RESULTS

We found that PSI evolved towards lower values (i.e., higher proliferative fractions) over the fractionation RT treatment course. For patients that began treatment with standard fractionation, no adaption was found to be superior to uniform fractionation. For selected patients who began treatment with hyperfractionation, however, the optimal fractionation schedule included a period of upfront hyperfractionated RT followed by a switch to standard fractionation at different times during their treatment course.

CONCLUSION

The results of this study suggest that in addition to selecting the best initial fractionation schedule, a novel approach to personalize RT for OPC patients may include adapting the fractionation based on early treatment response dynamics. These results motivate validation in prospective clinical trials.

External validation of Fetal Medicine Foundation competing-risks model for midgestation prediction of small-for-gestational-age neonates in Spanish population

OBJECTIVE

To examine the external validity of the new Fetal Medicine Foundation (FMF) competing-risks model for prediction in midgestation of small-for-gestational-age (SGA) neonates.

METHODS

This was a single-center prospective cohort study of 25 484 women with a singleton pregnancy undergoing routine ultrasound examination at 19 + 0 to 23 + 6 weeks' gestation. The FMF competing-risks model for the prediction of SGA combining maternal factors and midgestation estimated fetal weight by ultrasound scan (EFW) and uterine artery pulsatility index (UtA-PI) was used to calculate risks for different cut-offs of birth-weight percentile and gestational age at delivery. The predictive performance was evaluated in terms of discrimination and calibration.

RESULTS

The validation cohort was significantly different in composition compared with the FMF cohort in which the model was developed. In the validation cohort, at a 10% false-positive rate (FPR), maternal factors, EFW and UtA-PI yielded detection rates of 69.6%, 38.7% and 31.7% for SGA < 10th percentile with delivery at < 32, < 37 and ≥ 37 weeks' gestation, respectively. The respective values for SGA < 3rd percentile were 75.7%, 48.2% and 38.1%. Detection rates in the validation cohort were similar to those reported in the FMF study for SGA with delivery at < 32 weeks but lower for SGA with delivery at < 37 and ≥ 37 weeks. Predictive performance in the validation cohort was similar to that reported in a subgroup of the FMF cohort consisting of nulliparous and Caucasian women. Detection rates in the validation cohort at a 15% FPR were 77.4%, 50.0% and 41.5% for SGA < 10th percentile with delivery at < 32, < 37 and ≥ 37 weeks, respectively, which were similar to the respective values reported in the FMF study at a 10% FPR. The model had satisfactory calibration.

CONCLUSION

The new competing-risks model for midgestation prediction of SGA developed by the FMF performs well in a large independent Spanish population. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Development of chronic pain after episiotomy

OBJECTIVE

To analyze the incidence of chronic pain 5 months after episiotomy, as well as potential prognostic factors.

METHODS

A prospective cohort observational study was conducted on pregnant women age≥18 years who had undergone an episiotomy. The presence of pain was evaluated in the area of episiotomy at 24 and 48 h of delivery using a structured face-to-face questionnaire, and by telephone questionnaire at 5 months. The primary endpoint was the presence of persistent pain at 5 months. A record was made of the presence of pain at delivery, and its intensity, the presence or absence of epidural analgesia, instrumental delivery, perineal tear, and pain when episiotomy was performed, as well as the presence of dyspareunia and urinary incontinence at 5 months post-episiotomy.

RESULTS

A total of 87 parturient patients were included, of whom 78 completed the study. Of the patients who completed the study, 12.8% reported chronic episiotomy pain. Epidural analgesia was associated with a higher incidence of instrumental delivery and less pain at the time of episiotomy and expulsion (P<.0005, P<.02, and P<.01, respectively). Chronic pain is associated with operative delivery (P<.017), and with the presence of pain at rest at 24 and 48 h (P<.01), of wound complications (P<.026), and of dyspareunia (P<.001).

CONCLUSION

An incidence of 12.8% of women developing chronic pain after delivery with episiotomy suggests a health problem. More studies are needed to confirm our results.

[Factors determining patient satisfaction with the pre-anaesthesia consultation]

OBJECTIVE

To analyse patient satisfaction with care provided in the pre-anaesthetic consultation and its determining factors.

MATERIAL AND METHOD

An anonymous questionnaire was randomly distributed to patients attending a pre-anaesthesia clinic, which included 4 questions with 5 possible answers on a (very dissatisfied, dissatisfied, fairly satisfied, satisfied and very satisfied) categorical graduated scale related to punctuality, understanding of the information received, respectful treatment, and overall satisfaction. The fifth question was about the knowledge or the name of the anaesthesiologist who attended them. A binary logistic regression model was used, which identified the predictors of satisfaction, calculated the odds ratios, and their respective 95% confidence intervals.

RESULTS

A total of 4006 questionnaires were analysed, in which 99.2% (3966) of users rated as satisfied/very satisfied the question about the respectful treatment, 98.4% (3937) of the information received and understanding, 77.4% (3096) punctuality in attending, and 97, 6% (3909) overall satisfaction. Almost three-quarters (71%, 2844) did not know the name of the anaesthesiologist. Regression analysis associated the more satisfied with their treatment (OR 17.44; P<.0005) and the information received (OR 14.94, P<.0005), while punctuality (OR 5 40; P<.0005) was the factor that contributed less to the result.

CONCLUSION

In our population satisfaction in pre-anaesthesia consultation is due mainly to the communication skills of the anaesthesiologist.

Analysis of quality of nuchal translucency measurements: its role in prenatal diagnosis

Objective. Quantitative analysis of the quality of nuchal translucency (NT) measurements. Methods. First-trimester combined screening for Down syndrome was performed to all pregnant women attended in our Department from October 2003 to November 2009. NT was measured according to the Fetal Medicine Foundation (FMF) criteria by 20 trained obstetricians. The performance of NT measurements was retrospectively analyzed with regard to several quality control standards. Accuracy according to experience, professional profile, crown rump length (CRL) values, and FMF certification was statistically tested. Results. A total of 14978 NT measurements were assessed. (1) The mean operator-specific median NT-MoM values was 0,98. (2) Mean percentage of cases >95th and <5th centiles were 5,0% and 4,2%, respectively. (3) Logarithmic mean and SD of the NT MoM values were 0,00 and 0,13, respectively. (4) The DR for trisomy 21 at screening time was 90,7% for a FPR of 6,7% for standard screening strategy. (5) According to Cumulative SUM (CUSUM) figures, the performance was more acceptable in FMF-certified operators. Conclusion. Overall, quality standards show optimal NT measurements in our unit. Operator experience, a dedicated profile to fetal medicine, CRL over 60 mm, and FMF certification have a significant positive impact on the quality standards.

Spinal anaesthesia with 0.5% isobaric bupivacaine in patients with diabetes mellitus: the influence of CSF composition on sensory and motor block

BACKGROUND AND OBJECTIVE

We investigated cerebrospinal fluid characteristics in patients with and without diabetes mellitus and the influences that changes in these characteristics have on sensory and motor block when spinal anaesthesia is performed.

METHODS

We included 44 patients in each study group. All received spinal administration of 15 mg of 0.5% isobaric bupivacaine. Blood and cerebrospinal fluid were analysed for glucose, total protein, urea, albumin, immunoglobulin G, sodium, chloride, potassium, calcium, magnesium and osmolarity as well as the performance of the local anaesthetic from establishment until complete regression of sensory and motor block.

RESULTS

The cerebrospinal fluid of the two groups differed significantly (P < 0.05) in the levels of total protein, albumin, immunoglobulin G, glucose and osmolarity. Sensory and motor block was established more rapidly in the diabetic group (P < 0.05), and the total duration from maximum block until regression to two dermatomes was greater (P < 0.05), as was the complete regression from sensory and motor block (P < 0.05).

CONCLUSION

This study shows that diabetes mellitus has an influence on sensory and motor block after the administration of spinal isobaric bupivacaine.

Detailed localization of aquaporin-4 messenger RNA in the CNS: preferential expression in periventricular organs

We have performed a detailed in situ hybridization study of the distribution of aquaporin-4 messenger RNA in the CNS. Contrary to expectation, we demonstrate that aquaporin-4 is ubiquitously expressed in the CNS. Strong hybridization labeling was detected in multiple olfactory areas, cortical cells, medial habenular nucleus, bed nucleus of the stria terminalis, tenia tecta, pial surface, pontine nucleus, hippocampal formation and multiple thalamic and hypothalamic areas. A low but significant hybridization signal was found, among others, in the choroid plexus of the lateral ventricles, ependymal cells, dorsal raphe and cerebellum. Overall, a preferential distribution of aquaporin-4 messenger RNA-expressing cells was evident in numerous periventricular organs. From the distribution study, the presence of aquaporin-4 messenger RNA-expressing cells in neuronal layers was evident in neuronal layers including the CA1 -CA3 hippocampal pyramidal cells, granular dentate cells and cortical cells. Further evidence of neuronal expression comes from the semicircular arrangement of aquaporin-4 messenger RNA-expressing cells in the bed nucleus of the stria terminalis and medial habenular nucleus exhibiting Nissl-stained morphological features typical of neurons. Combined glial fibrillary acidic protein immunohistochemistry and aquaporin-4 messenger RNA in situ hybridization demonstrated that aquaporin-4 messenger RNA is expressed by glial fibrillary acidic protein-lacking cells. We conclude that aquaporin-4 messenger RNA is present in a collection of structures typically involved in the regulation of water and sodium intake and that aquaporin-4 water channels could be the osmosensor mechanism responsible for detecting changes in cell volume by these cells.

Regulation of aquaporin mRNA expression in rat kidney by water intake

Three aquaporins (AQP) are present in the membrane of the principal collecting duct cells. On the apical side, the levels of AQP2 protein are increased in response to both arginine vasopressin and water deprivation. However, whether this change parallels changes in the abundance of AQP3 and AQP4 in the basolateral membrane is less well known. This study evaluates the effect of either dehydration or water loading on the rat kidney mRNA expression of AQP2, AQP3, and AQP4. Poly(A+)RNA was prepared from renal cortex and medulla of control, water-deprived, well hydrated, and water-deprived rats treated with OPC31260, a V2 receptor antagonist. Northern blots were done and mRNA levels were quantified using a PhosphorImager system. Relative to control, water deprivation increased the expression of cortical AQP2, -3, and -4, whereas water loading decreased the cortical and medullar expression of AQP2, -3, and -4. Therefore, in addition to AQP2 and -3, AQP4 expression is also regulated by water intake. Treatment with OPC31260 (40 mg/kg of weight per d) inhibited up to 20 to 30% the upregulation of AQP-mRNA induced by water deprivation. Blood values of arginine vasopressin and aldosterone were significantly increased by water deprivation, whereas they were unchanged by water overloading. Taken together, these results indicate that renal AQP2, -3, and -4 expression is regulated in a coordinated manner. Simultaneous up- or downregulation of the three transcripts occurred upon either water deprivation or water loading of animals, respectively. However, the signaling mechanism for the two long-term adaptive processes may be different, and, in addition to arginine vasopressin, other factors may be involved in the transcriptional regulatory processes.

The influence of the menstrual cycle in postdural puncture headache

BACKGROUND AND OBJECTIVES

We performed a preliminary study to analyze the influence of the menstrual cycle on the incidence of postdural puncture headache (PDPH).

METHODS

One hundred sixty female patients with regular menstrual cycles who received spinal anesthesia were observed. Based on the day within the menstrual cycle that they received the puncture, the patients were classified into period A (perimenstrual) or period B (postmenstrual). The possible relationship among headaches, lifestyle habits, and anesthetic technique, and the presence of PDPH were analyzed, as were the levels of female sex hormones with PDPH in comparison with a control group.

RESULTS

Seven cases of PDPH (4.3%) were observed--one within the perimenstrual group and six in the postmenstrual group. No significant differences were observed between the two periods or were there any differences in relating PDPH to the other variables analyzed.

CONCLUSIONS

According to our results, the menstrual cycle and hormonal levels may not have any influence on the appearance of PDPH in female patients, although a larger series is required to validate these results.

Localization of the human gene for aquaporin 3 (AQP3) to chromosome 9, region p21-->p12, using fluorescent in situ hybridization

The chromosome location of the gene encoding aquaporin 3 (AQP3), which functions as a channel for water and small polar solutes in the basolateral membrane of the collecting duct of the kidney, was determined. In situ hybridization on metaphase chromosomes allowed the assignment of human AQP3 to chromosome 9p21-->p12.

[Current situation of anesthesiology research in Andalucia and Extremadura. Comparative study with the rest of Spain]

OBJECTIVES

To examine the quality and quantity of scientific research in anesthesiology in Andalucia and Extremadura, comparing them with the rest of Spain.

MATERIAL AND METHODS

We conducted a retrospective study of publications (original research articles and clinical notes) by spanish authors whose abstracts appeared in the MEDLINE data base from 1990 to 1994. Quality of research design was assessed with the classification system of Fletcher and Fletcher, who categorize works and being either descriptive or analytical. Comparative analysis was in reference to the total number of anesthesiologists.

RESULTS

Anesthesiologists working in Andalucía and Extremadura make up 21.7% of the total number in Spain, yet fewer publications came from these regions (17%). The proportion of analytical designs, however, was significantly higher (60% versus 44%; p = 0.05). Publications were similar in other ways, though there was a higher proportion of articles from non-anesthesiologists in Andalucía and Extremadura (p = 0.02). Most publications adressed clinical questions.

CONCLUSIONS

Although there is less scientific publication coming from Andalucía and Extremadura in the field of anesthesiology, its quality is acceptable and seems to be improving.

Aquaporin-3 water channel localization and regulation in rat kidney

The aquaporins are a family of water channels expressed in several water-transporting tissues, including the kidney. We have used a peptide-derived, affinity-purified polyclonal antibody to aquaporin-3 (AQP-3) to investigate its localization and regulation in the kidney. Immunoblotting experiments showed expression in both renal cortex and medulla, with greatest expression in the base of the inner medulla. Subcellular fractionation of membranes, using progressively higher centrifugation speeds, revealed that AQP-3 is present predominantly in the 4,000 and 17,000 g pellets and, in contrast to AQP-2, is virtually absent in the high-speed (200,000 g) pellet that contains small intracellular vesicles. Immunocytochemistry and immunofluorescence studies revealed that labeling is restricted to the cortical, outer medullary, and inner medullary collecting ducts. Within the collecting duct, principal cells were labeled, whereas intercalated cells were unlabeled. Consistent with previous immunofluorescence studies (K. Ishibashi, S. Sasaki, K. Fushimi, S. Uchida, M. Kuwahara, H. Saito, T. Furukawa, K. Nakajima, Y. Yamaguchi, T. Gojobori, and F. Marumo. Proc. Natl. Acad. Sci. USA 91: 6269-6273, 1994; T. Ma, A. Frigeri, H. Hasegawa, and A. S. Verkman. J. Biol. Chem. 269: 21845-21849, 1994), the labeling was confined to the basolateral domain. Immunoelectron microscopy, using the immunogold technique in ultrathin cryosections, demonstrated a predominant labeling of the basolateral plasma membranes. In contrast to previous findings with AQP-2, there was only limited AQP-3 labeling of intracellular vesicles, suggesting that this water channel is not regulated acutely through vesicular trafficking. Immunoblotting studies revealed that thirsting of rats for 48 h approximately doubled the amount of AQP-3 protein in the inner medulla. These studies are consistent with a role for AQP-3 in osmotically driven water absorption across the collecting duct epithelium and suggest that the expression of AQP-3 is regulated on a long-term basis.

Cloning and expression of AQP3, a water channel from the medullary collecting duct of rat kidney

The terminal part of the inner medullary collecting duct exhibits a high degree of water permeability that is independent of increased intracellular cAMP and not accounted for by the activity of the known renal epithelial water channels CHIP28 (28-kDa channel-forming integral protein) and WCH-CD (collecting duct water channel protein). Starting with rat kidney papilla mRNA, reverse transcription PCR was performed with degenerate primers assuming that the putative channel would be a member of the major intrinsic protein (MIP) family of proteins. A cDNA fragment was identified and used to screen a rat kidney cDNA library. A 1.9-kb cDNA clone was isolated. The open reading frame of 876 bp coded for a protein of 292 amino acids (M(r), 31,431). Aquaporin 3 (AQP3; 31.4-kDa water channel protein) is a newly discovered member of the MIP family. Northern blot analysis showed a single transcript for AQP3 of approximately 1.9 kb present in the renal medulla, predominantly in the inner medulla. With in situ hybridization, abundant message was found in the cells of the medullary collecting ducts. Injection of the complementary RNA of AQP3 into Xenopus oocytes markedly increased the osmotic water permeability. This permeability had an energy of activation of 3.0 kcal/mol (1 cal = 4.184 J), it was fully blocked by 1 mM p-chloromercuriphenylsulfonate, and this inhibition was reversed by 5 mM dithiothreitol. cAMP did not increase this water permeability. AQP3 did not permit passage of monovalent ions (Na, K, Cl); however, it is slightly permeable to urea. The present study demonstrates the existence of an additional water channel, AQP3, in epithelial cells of the medullary collecting duct.

Water and urea diffusive permeabilities in isolated proximal tubule cells

We measured the water (3H2O) and urea ([14C]urea) diffusive permeabilities (Pd) in intact proximal tubule cells (PTC). Isolated rabbit PTC were packed in polyethylene tubes to measure the diffusion coefficients for 3H2O and [14C]urea at 14 degrees C. Pd values for water and urea were estimated from the diffusion coefficients in intact cells, in extracellular and in intracellular media using a model of parallel and series diffusion in the packed PTC. Pd was 65 +/- 8 and 18 +/- 3 microns/s for water and urea, respectively. We examined the effect of different pharmacological agents on the Pd values for water and for urea. p-Chloromercuribenzenesulfonate at 2 mM markedly inhibited the Pd of water and urea. Phloretin (1 mM) inhibited the Pd for urea, whereas it increased Pd for water. KMnO4 (30 microM) markedly inhibited urea Pd but did not alter water Pd. The values for energy of activation of Pd for water and for urea were 2.9 +/- 2 and 7.3 +/- 4 kcal/mol, respectively. These results show that water and urea do not share the same pathway across the PTC membrane.

Expression of multiple water channel activities in Xenopus oocytes injected with mRNA from rat kidney

To test the hypothesis that renal tissue contains multiple distinct water channels, mRNA prepared from either cortex, medulla, or papilla of rat kidney was injected into Xenopus oocytes. The osmotic water permeability (Pf) of oocytes injected with either 50 nl of water or 50 nl of renal mRNA (1 microgram/microliter) was measured 4 d after the injection. Pf was calculated from the rate of volume increase on exposure to hyposmotic medium. Injection of each renal mRNA preparation increased the oocyte Pf. This expressed water permeability was inhibited by p-chloromercuriphenylsulfonate and had a low energy of activation, consistent with the expression of water channels. The coinjection of an antisense oligonucleotide for CHIP28 protein, at an assumed > 100-fold molar excess, with either cortex, medulla, or papilla mRNA reduced the expression of the water permeability by approximately 70, 100, and 30%, respectively. Exposure of the oocyte to cAMP for 1 h resulted in a further increase in Pf only in oocytes injected with medulla mRNA. This cAMP activation was not altered by the CHIP28 antisense oligonucleotide. These results suggest that multiple distinct water channels were expressed in oocytes injected with mRNA obtained from sections of rat kidney: (a) CHIP28 water channels in cortex and medulla, (b) cAMP-activated water channels in medulla, and (c) cAMP-insensitive water channels in papilla.

Optical measurement of osmotic water transport in cultured cells. Role of glucose transporters

Methodology was developed to measure osmotic water permeability in monolayer cultured cells and applied to examine the proposed role of glucose transporters in the water pathway (1989. Proc. Natl. Acad. Sci. USA. 86:8397-8401). J774 macrophages were grown on glass coverslips and mounted in a channel-type perfusion chamber for rapid fluid exchange without cell detachment. Relative cell volume was measured by 45 degrees light scattering using an inverted microscope; measurement accuracy was validated by confocal imaging microscopy. The time required for greater than 90% fluid exchange was less than 1 s. In response to a decrease in perfusate osmolality from 300 to 210 mosM, cells swelled without lag at an initial rate of 4.5%/s, corresponding to a water permeability coefficient of (6.3 +/- 0.4) x 10(-3) cm/s (SE, n = 20, 23 degrees C), assuming a cell surface-to-volume ratio of 4,400 cm-1. The initial rate of cell swelling was proportional to osmotic gradient size, independent of perfusate viscosity, and increased by amphotericin B (25 micrograms/ml), and had an activation energy of 10.0 +/- 1 kcal/mol (12-39 degrees C). The compounds phloretin (20 microM) and cytochalasin B (2.5 micrograms/ml) inhibited glucose transport by greater than 85% but did not influence Pf in paired experiments in which Pf was measured before and after inhibitor addition. The mercurials HgCl2 (0.1 mM) and p-chloromercuribenzoate (1 mM) did not inhibit Pf. A stopped-flow light scattering technique was used to measure Pf independently in J774 macrophages grown in suspension culture. Pf in suspended cells was (4.4 +/- 0.3) x 10(-3) cm/s (assuming a surface-to-volume ratio of 8,800 cm-1), increased more than threefold by amphotericin B, and not inhibited by phloretin and cytochalasin B under conditions of strong inhibition of glucose transport. The glucose reflection coefficient was 0.98 +/- 0.03 as measured by induced osmosis, assuming a unity reflection coefficient for sucrose. These results establish a quantitative method for measurement of osmotic water transport in adherent cultured cells and provide evidence that glucose transporters are not involved in the water transporting pathway.

Left ventricular performance before and after removal of the noncontractile area of the left ventricle and revascularization of the myocardium

The left ventricular volume and the internal surface areas of noncontractile regions were measured by cineangiocardiography at 60 frames/sec in nine patients with a chronic localized noncontractile area of the left ventricle. Arteriosclerotic heart disease was proven in eight patients by means of coronary arteriography. Left ventricular end-diastolic pressure, stroke volume, ejection fraction, mean circumferential shortening, and cardiac output were also measured before and after removal of the noncontractile area and revascularization of the myocardium.

The noncontractile areas, measured at end-diastole, ranged from 12 to 40% of the internal surface area of the left ventricle. Generally, impairment of the left ventricular function depended on the size of the noncontractile areas. The end-diastolic volume was approximately 150 ml/m 2 when the size of noncontractile areas exceeded 20-25% of the left ventricular surface area (r = +0.72; P < 0.05). The ejection fraction decreased as the size of the noncontractile areas increased (r = –0.81; P < 0.01). Following surgery, the left ventricular function, as well as the clinical condition, improved significantly, although the cardiac performance remained in the abnormal range in most patients. The ejection fraction increased ( P < 0.05), and the percent circumferential shortening also improved ( P < 0.05).

Removal of the noncontractile area of the left ventricle and revascularization of the myocardium improved the cardiac performance and increased the sense of well being in these patients.