Do weak readers in rural India automatically read same language subtitles on Bollywood films? An eye gaze analysis

Same Language Subtitling (SLS) of audio-visual content on mainstream TV entertainment to improve mass reading literacy was first conceived and piloted in India. SLS is now being scaled up nationally to ensure that the reading skills of one billion TV viewers, including 600 million weak readers, remain on a lifelong pathway to practice, progress, and proficiency. Will weak readers ignore or try to read along with SLS? Our eye-tracking study investigates this question with 136 weak readers drawn from a remote village in Rajasthan state by showing them popular Hindi film clips of dialog and songs, with and without SLS. We developed an interactive web-based visual analytics tool for exploring eye-tracking data. Based on an analysis of fixations, saccades, and time spent in the subtitle and non-subtitle areas, our main finding is that 70 percent of weak readers engaged in unprompted reading while watching film clips with SLS. We observed that saccadic eye movement is a good indicator to quantify the amount of reading with SLS, and saccadic regression can further differentiate weak readers. Eye-tracking studies of weak readers watching subtitles are rare, and ours may be the first with subjects from rural India.

Comprehensive case management of malaria: Operational research informing policy

In 2013, the Odisha state Vector Borne Disease Control Programme led a five year operational research project, under programmatic conditions, in close collaboration with several partners. This Comprehensive Case Management Project covered a population of 900,000 across paired control and intervention blocks in four districts, each with different transmission intensities. Key gaps in access to malaria services were identified through household surveys and a detailed situation analysis. The interventions included ensuring adequate stocks of rapid diagnostic tests and antimalarial drugs at the village level, the capacity building of health workers and ASHAs, setting up microscopy centres at the primary health care level, and conducting mass screening and treatment in poorly accessible areas. The programme strengthened the routine health system, and improved malaria surveillance as well as the access to and quality of care. Initially, the programme led to increased case reporting due to improved detection, followed by a decline in malaria incidence. Lessons from the project were then scaled up statewide in the form of a new initiative-Durgama Anchalare Malaria Nirakaran (DAMaN).

Stress dose steroids in renal transplant patients undergoing lymphocele surgery

The requirement for perioperative stress dose steroids (SDS) in patients on long-term steroid therapy is controversial, but SDS are given during perioperative care. Studies focusing on surrogate outcomes like cortisol levels indicate a possible requirement for SDS, but clinical results are sparse. We retrospectively compared outcomes of renal or pancreas/kidney transplant patients undergoing surgical lymphocele drainage who did (n=20) or did not (n=38) receive SDS. Patients had similar demographic characteristics (P=NS). No patient developed hypotension (SBP < 80 mmHg), mental status change, unexplained arthralgias, or ileus. Impaired wound healing occurred in one patient in each group (P=NS), and lymphocele recurrence occurred in 25% of the SDS group and 10.5% of the other group (P=.25). SBP decreased from baseline in both groups (P <.001) but did not differ between groups, and maximum blood glucose was higher in the SDS group (P=.04). No difference was observed in other measured parameters. These data indicate that SDS increased the risk of hyperglycemia and provided no apparent benefit. A prospective study is warranted to confirm these findings.

Combined use of sirolimus and voriconazole in renal transplantation: A report of two cases

Voriconazole is currently contraindicated for use with sirolimus. We report our experience with voriconazole/sirolimus in two renal transplant recipients. To our knowledge, this is the first experience with voriconazole/sirolimus. An interaction requiring a 75% to 87.5% sirolimus dose reduction was noted, but goal trough levels and clinical tolerability were achieved.

Clinical spectrum of HIV infection

OBJECTIVE

To study the modes of transmission of pediatric HIV infection, to categorize clinical manifestations and to compare clinical spectrum of perinatal with transfusion acquired HIV infection.

DESIGN

Case series study.

SETTING

Hospital based pediatric HIV clinic.

METHODS

Children confirmed to have HIV infection were evaluated and relevant details recorded.

RESULTS

55 children were enrolled of whom 41 (74.5%) had perinatal transmission of HIV, 12 (21.8%) were infected through blood transfusions and 2 (3.6%) through other routes. Thirty-seven (90.2%) of the 41 perinatally infected children were symptomatic. Tuberculosis was seen in 25 (67.5%) of these children and failure to thrive in 18 (48.6%). Nonspecific features such as recurrent bacterial infection, oral candidiasis and chronic diarrhea were other manifestations. Eight (26.3%) of the 30 children available for follow up for a median period of 9 months died at the median age of 8.5 months. Amongst the transfusion acquired HIV infection, 11 (91.6%) of the 12 were asymptomatic at presentation. Six (50%) of these children died at the median age of 3 years and the remaining 6 had no major symptoms at a median follow up of 3.5 years.

CONCLUSION

Perinatal route is the major route of HIV transmission in children and clinical manifestations are different from those of adults.

Structural consequences of D-amino acids in collagen triple-helical peptides

The effects of racemization of aspartic acid on triple-helical formation have been studied using a "host-guest" peptide approach where selected guest Gly-Xaa-Yaa triplets were included within a common acetyl-(Gly-Pro-Hyp)3-Gly-Xaa-Yaa-(Gly-Pro-Hyp)4-Gly-Gly-amide frame-work. Four guest triplets, Gly-Asp-Hyp and Gly-Asp-Ala where Asp is either L-Asp or D-Asp were studied. Thermal stability data indicated that incorporation of D-Asp residues prevented triple-helix formation in phosphate buffered saline, although triple-helical structures were formed in a stabilizing solvent, 67% aqueous ethylene glycol. In this solvent the melting temperatures of D-Asp containing peptides were more than 30 degrees C lower than the corresponding peptides containing L-Asp. For Gly-Asp-Ala peptides, but not Gly-Asp-Hyp, peptides, melting profiles indicated that a mixture of the D- and L-Asp containing peptides were able to form heterotrimer triple-helical molecules. These studies illustrate the dramatic destabilizing effect of D-amino acids on the triple-helix stability, but indicate that they can be accommodated in this conformation.

Gly-X-Y tripeptide frequencies in collagen: a context for host-guest triple-helical peptides

The collagen triple-helix consists of a repeating (Gly-X-Y)n sequence. In theory, there are more than 400 possible Gly-X-Y triplets, but analysis of sequences from fibrillar and nonfibrillar collagens shows that only a limited set of triplets are found in significant numbers, and many are never observed. The nonrandom frequency of Gly-X-Y triplets makes it practical to experimentally approach the stability of much of the collagen sequence through the study of a limited set of host-guest peptides. In these peptides, individual Gly-X-Y triplets constitute the guest, while the host consists of Gly-Pro-Hyp tripeptides. A set of host-guest peptides was designed to contain the most common nonpolar and charged triplets found in collagen. All formed stable triple-helices, with their melting temperature depending on the identity of the guest triplet. While including less than 10% of all possible triplets, the data set covers 50-60% of collagen sequences and provides a starting point for establishing a stability scale to predict the relative stability of important collagen regions, such as the matrix metalloproteinase cleavage site or binding sites.

Structural consensus in ligand-protein docking identifies recognition peptide motifs that bind streptavidin

Computational structure prediction of streptavidin-peptide complexes for known recognition sequences and a number of random di-, tri-, and tetrapeptides has been conducted, and mechanisms of peptide recognition with streptavidin have been investigated by a new computational protocol. The structural consensus criterion, which is computed from multiple docking simulations and measures the accessibility of the dominant binding mode, identifies recognition motifs from a set of random peptide sequences, whereas energetic analysis is less discriminatory. The predicted conformations of recognition tripeptide and tetrapeptide sequences are also in structural harmony and composed of peptide fragments that are individually unfrustrated in their bound conformation, resulting in a minimally frustrated energy landscape for recognition peptides.

Gly-Gly-containing triplets of low stability adjacent to a type III collagen epitope

Collagens, in addition to their structural role in the extracellular matrix, possess a number of functional binding domains. In this study, the binding to collagen of a monoclonal antibody is used as a model to define the molecular features involved in triple-helix interactions with other proteins. Here we report the thermal stability of an overlapping set of triple-helical peptides that includes the epitope recognized by a monoclonal antibody to type III collagen. Although the sequences of these peptides are very closely related, by a translation of a single triplet along the collagen chain, substantial variations in the melting temperatures were observed. These variations in thermal stability could not be readily explained by differences in imino acid content, or in numbers of charged or hydrophobic residues. The results indicate that Gly-Gly-Y triplets, which are adjacent to the epitope, have a strong influence in reducing the thermal stability of triple-helical peptides. Further studies, which were carried out on a set of "host-guest" triple-helical peptides containing different Gly-Gly-Y guest triplets, confirm the destabilizing effect of such tripeptides. The presence of Gly-Gly-Y triplets may play an important role in specific functions of type III collagen by modulating the local triple-helical structure or dynamics.

Effects of motion, ambient light, and hypoperfusion on pulse oximeter function

STUDY OBJECTIVE

To compare the performance of five pulse oximeters during hypoperfusion, probe motion, and exposure to ambient light interference.

DESIGN

Prospective study.

SETTING

Laboratory facility at a university medical center.

PATIENTS

8 unanesthetized, ASA physical status I volunteers.

INTERVENTIONS

We evaluated five common pulse oximeters with respect to three scenarios: (1) an operating room light was shone on oximeter probes, (2) a motion generator was used to generate 2 Hz and 4 Hz hand motion, and (3) a pneumatic compression device overlying the brachial artery was used to simulate hypoperfusion. Electrocardiographic (ECG) and arterial blood gas values were considered gold standards for heart rate (HR) and oxygen saturation (SpO2) respectively. SpO2 nondisplay and values greater than 4% from simultaneous arterial SaO2-oximeter values were defined as errors. Nondisplay of HR, or HR greater than 5% from ECG values, were also considered errors.

MEASUREMENTS AND MAIN RESULTS

The Ohmeda and Nellcor N200 with finger probe had the highest total failure rates with respect to both SpO2 and HR due to ambient light interference (p < 0.05). The Nellcor N200 with finger probe and N200 with C lock were the most accurate with regard to SpO2 during 2 Hz and 4 Hz motion (p < 0.05). However, all oximeters failed dramatically during 4 Hz motion when measuring HR. In the hypoperfusion model, the Nellcor N200 with finger probe and the Nellcor C Lock oximeters performed significantly better than all others in terms of both HR and SpO2 (P < 0.05), while the Criticare oximeter failed 100% of the time.

CONCLUSION

There are significant differences in the accuracy of commercially available pulse oximeters during nonideal circumstances, with failure rates varying from approximately 5% to 50% depending on the oximeter and source of interference. Furthermore, no single oximeter performed the best under all conditions.

Pulse oximeter performance during desaturation and resaturation: a comparison of seven models

STUDY OBJECTIVE

To compare pulse oximeter performance during induced hypoxemia.

DESIGN

Prospective investigation in human volunteers.

SETTING

Laboratory facility at a university medical center.

PATIENTS

8 unanesthetized, healthy ASA physical status I volunteers.

INTERVENTIONS

We evaluated the accuracy and response times of seven popular pulse oximeters during induced hypoxemia. Arterial blood fractional oxygen saturation (SaO2) measurements were performed simultaneously and considered a gold standard.

MEASUREMENTS AND MAIN RESULTS

All oximeters were accurate (+/-2%) while subjects were breathing room air. During maximal hypoxemia (induced by breathing a FIO2 = 10% in nitrogen), large differences were noted between oxygen saturation as measured by pulse oximetry (SpO2) and SaO2 values, with pulse oximeters consistently underreporting SpO2 when actual SaO2 values were 75% or less. The Ohmeda 3740 (Ohmeda, Boulder, CO) using an ear probe was the first to detect desaturation (change in SpO2 > 3%) in 4 of 8 subjects (p < 0.05), and the Nellcor N200 reflectance oximeter (Nellcor, Inc., Pleasanton, CA) was first in 3 of 8 subjects (p < 0.05). During resaturation (after administering 100% oxygen), the Novametrix Oxypleth (Novametrix, Wallingford, CT) was significantly faster than other oximeters (p < 0.05) to return to baseline (SpO2 = 98%).

CONCLUSION

Most models of oximeters tested performed well when hemoglobin oxygen saturation was high, but all were inaccurate when SaO2 was approximately 75%. During induced hypoxemia, there were significant differences in the response times of oximeters tested, with no model demonstrably superior to others in all measures of performance.

Positron emission tomography study of regional cerebral metabolism in humans during isoflurane anesthesia

BACKGROUND

Although the anesthetic effects of the intravenous anesthetic agent propofol have been studied in the living human brain using brain imaging technology, the nature of the anesthetic state evident in the human brain during inhalational anesthesia remains unknown. To examine this issue, the authors studied the effects of isoflurane anesthesia on human cerebral glucose metabolism using positron emission tomography (PET).

METHODS

Five volunteers each underwent two PET scans; one scan assessed awake-baseline metabolism and the other scan assessed metabolism during isoflurane anesthesia titrated to the point of unresponsiveness (means +/- SD; expired = 0.5 +/- 0.1%). Scans were obtained with a GE2048 scanner (4.5-mm resolution-FWHM) using the 18fluorodeoxyglucose technique.

RESULTS

Awake whole-brain glucose metabolism averaged 6.9 +/- 1.5 mg.100 g-1.min-1 (means +/- SD). Isoflurane reduced whole-brain metabolism 46 +/- 11% to 3.6 +/- 0.3 mg.100 g-1.min-1 (P < or = 0.005). Regional metabolism decreased fairly uniformly throughout the brain, and no evidence of any regional metabolic increases were found in any brain region for any participant. A region-of-interest analysis showed that the pattern of regional metabolism evident during isoflurane anesthesia was not significantly different from that seen when participants were awake.

CONCLUSION

These data clarify that the anesthetic state evident in the living human brain during unresponsiveness induced with isoflurane is associated with a global, fairly uniform, whole-brain glucose metabolic reduction of 46 +/- 11%.

The effects of motion on the performance of pulse oximeters in volunteers (revised publication)

BACKGROUND

Pulse oximetry is considered a standard of care in both the operating room and the postanesthetic care unit, and it is widely used in all critical care settings. Pulse oximeters may fail to provide valid SpO2 data in various situations that produce low signal-to-noise ratio. Motion artifact is a common cause of oximeter failure and loss of accuracy. This study compares the accuracy and data dropout rates of three current pulse oximeters during standardized motion in healthy volunteers.

METHODS

Ten healthy volunteers were monitored by three different pulse oximeters: Nellcor N-200, Nellcor N-3000, and Masimo SET (prototype). Sensors were placed on digits 2, 3, and 4 of the test hand, which was strapped to a mechanical motion table. The opposite hand was used as a stationary control and was monitored with the same pulse oximeters and an arterial cannula. Arterial oxygen saturation was varied from 100% to 75% by changing the inspired oxygen concentration. While SpO2 was both constant and changing, the oximeter sensors were connected before and during motion. Oximeter errors and dropout rates were digitally recorded continuously during each experiment.

RESULTS

If the oximeter was functioning before motion began, the following are the percentages of time when the instrument displayed an SpO2 value within 7% of control: N-200 = 76%, N-3000 = 87%, and Masimo = 99%. When the oximeter sensor was connected after the beginning of motion, the values were N-200 = 68%, N-3000 = 47%, and Masimo = 97%. If the alarm threshold was chosen SpO2 less than 90%, then the positive predictive values (true alarms/total alarms) are N-200 = 73%, N-3000 = 81%, and Masimo = 100%. In general, N-200 had the greatest SpO2 errors and N-3000 had the highest dropout rates.

CONCLUSIONS

The mechanical motions used in this study significantly affected oximeter function, particularly when the sensors were connected during motion, which requires signal acquisition during motion. The error and dropout rate performance of the Masimo was superior to that of the other two instruments during all test conditions. Masimo uses a new paradigm for oximeter signal processing, which appears to represent a significant advance in low signal-to-noise performance.

Effects of motion on the performance of pulse oximeters in volunteers

BACKGROUND

Pulse oximetry is considered a standard of care in both the operating room and the postanesthetic care unit, and it is widely used in all critical care settings. Pulse oximeters may fail to provide valid pulse oximetry data in various situations that produce low signal-to-noise ratio. Motion artifact is a common cause of oximeter failure and loss of accuracy. This study compares the accuracy and data dropout rates of three current pulse oximeters during standardized motion in healthy volunteers.

METHODS

Ten healthy volunteers were monitored by three different pulse oximeters: Nellcor N-200, Nellcor N-3000, and Masimo SET (prototype). Sensors were placed on digits 2, 3, and 4 of the test hand, which was strapped to a mechanical motion table. The opposite hand was used as a stationary control and was monitored with the same pulse oximeters and an arterial cannula. Arterial oxygen saturation rate varied from 100% to 75% by changing the inspired oxygen concentration. While pulse oximetry was both constant and changing, the oximeter sensors were connected before and during motion. Oximeter errors and dropout rates were digitally recorded continuously during each experiment.

RESULTS

If the oximeter was functioning before motion began, the following are the percentages of time when the instrument displayed a pulse oximetry value within 7% of control: N-200 = 76%, N-3000 = 87%, and Masimo = 99%. When the oximeter sensor was connected after the beginning of motion, the values were N-200 = 68%, N-3000 = 47%, and Masimo = 97%. If the alarm threshold was chosen as pulse oximetry less than 90%, then the positive predictive values (true alarms/ total alarms) are N-200 = 73%, N-3000 = 81%, and Masimo = 100%. In general, N-200 had the greatest pulse oximetry errors and N-3000 had the highest dropout rates.

CONCLUSIONS

The mechanical motions used in this study significantly affected oximeter function, particularly when the sensors were connected during motion, which requires signal acquisition during motion. The error and dropout rate performance of the Masimo was superior to that of the other two instruments during all test conditions. Masimo uses a new paradigm for oximeter signal processing, which appears to represent a significant advance in low signal-to-noise performance.

A host-guest set of triple-helical peptides: stability of Gly-X-Y triplets containing common nonpolar residues

Host-guest peptide sets have been useful in evaluating the propensity of different amino acids to adopt an alpha-helical or beta-sheet form, and this concept is applied here to the triple-helical conformation. A set of host-guest peptides of the form acetyl-(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-GlyCONH2 was designed to evaluate the contribution of an isolated Gly-X-Y triplet to triple-helix stability in a defined environment. Peptides were synthesized to include guest triplets with the X and Y positions occupied by the most common nonpolar residues found in collagen: Pro (X position) and Hyp (Y position); Ala; Leu, the most frequent hydrophobic residue; and Phe, the only commonly occurring aromatic residue. The guest triplets of the 12 peptides synthesized represent 35% of the sequence found in the alpha 1 chain of type I collagen. All peptides formed stable triple-helical structures, and the peptides showed a range of thermal stabilities (Tm = 21-44 degrees C), depending on the identity of the guest triplet. Thermodynamic calculations indicate these peptides have a range of free energy values (delta delta G = 9 kcal/mol) and suggest that favorable entropy is the dominant factor in increased stability. Replacement of Ala by Leu in the X position did not affect the thermal stability, while an Ala to Leu change in the Y position was destabilizing. These data provide experimental evidence that hydrophobic residues do not stabilize the triple helical conformation. Although Leu and Phe are found almost exclusively in the X position in collagens, peptides with Leu and Phe in the Y position formed stable triple-helices. This supports the hypothesis that the X positional preference of these residues relates to their increased potential for intermolecular hydrophobic interactions rather than their destabilization of the triple-helical molecule. These studies establish the utility of host-guest peptides in defining a scale of triple-helix propensities and in clarifying the interactions stabilizing the triple-helical conformation.

Protein motifs. 8. The triple-helix motif in proteins

The triple helix is an important motif found in the family of collagens as well as a set of host-defense proteins. This conformation may be identified by its strict sequence constraints, including glycine as every third residue and a high content of imino acids. The first high-resolution structure available for a triple helix has confirmed the model of three supercoiled polyproline II-like helices and has defined a highly ordered water network whose regularity depends on the presence of 4-hydroxyproline. The role of the rod-like triple helix lies in its capacity to self-associate in a variety of forms as well as its ability to bind a wide range of ligands. The extensive hydrogen-bonded water network, together with the high content of sterically restricted imino acids, are the major contributors to the stabilization of triple helices, whereas electrostatic and hydrophobic interactions define intermolecular association and ligand binding. Mutations in the repeating Gly-X-Y sequences of triple helices have been shown to cause a variety of human diseases.

Cerebral metabolism during propofol anesthesia in humans studied with positron emission tomography

BACKGROUND

Although the effects of propofol on cerebral metabolism have been studied in animals, these effects have yet to be directly examined in humans. Consequently, we used positron emission tomography (PET) to demonstrate in vivo the regional cerebral metabolic changes that occur in humans during propofol anesthesia.

METHODS

Six volunteers each underwent two PET scans; one scan assessed awake-baseline metabolism, and the other assessed metabolism during anesthesia with a propofol infusion titrated to the point of unresponsiveness (mean rate +/- SD = 7.8 +/- 1.5 mg.kg-1.h-1). Scans were obtained using the 18fluorodeoxyglucose technique.

RESULTS

Awake whole-brain glucose metabolic rates (GMR) averaged 29 +/- 8 mumoles.100 g-1.min-1 (mean +/- SD). Anesthetized whole-brain GMR averaged 13 +/- 4 mumoles.100 g-1.min-1 (paired t test, P < or = 0.007). GMR decreased in all measured areas during anesthesia. However, the decrease in GMR was not uniform. Cortical metabolism was depressed 58%, whereas subcortical metabolism was depressed 48% (P < or = 0.001). Marked differences within cortical regions also occurred. In the medial and subcortical regions, the largest percent decreases occurred in the left anterior cingulate and the inferior colliculus.

CONCLUSION

Propofol produced a global metabolic depression on the human central nervous system. The metabolic pattern evident during anesthesia was reproducible and differed from that seen in the awake condition. These findings are consistent with those from previous animal studies and suggest PET may be useful for investigating the mechanisms of anesthesia in humans.

Cytogenetic and FISH analysis of endometrial carcinoma

Endometrial cancer is a common gynecologic tumor, yet reports of cytogenetic studies are few. We studied chromosomes from seven primary specimens of endometrial cancer. Six had abnormal chromosomes; five had a diploid-hyperdiploid modal number and one was triploid. One specimen had a normal karyotype. Chromosome 1 was frequently involved in abnormalities (five tumors) with i(1q) in two tumors, and one tumor each had der(7)t(1;7)(q12;p11) and +add (1)(p13). One additional tumor had trisomy 1 in the single cell which could be fully analyzed. Trisomy 7 was noted in two tumors, and trisomy 10 in one. Because trisomies of these chromosomes have been reported in other cases of endometrial cancer, we used fluorescent in situ hybridization (FISH) with centromere probes to determine the prevalence of trisomies 7 and 10 in these specimens. No additional tumors were found to have trisomies 7 or 10 by FISH. Our data, in combination with published literature, suggest that additional copies of 1q or portions of 1q constitute the primary change in this tumor. Extra copies of genes in this region may play an important role in tumorigenesis in endometrial carcinoma.

The effect of sensor malpositioning on pulse oximeter accuracy during hypoxemia

BACKGROUND

Previous studies have shown that pulse oximeters whose sensors are positioned improperly may yield erroneously low saturation (SpO2) values on normoxemic subjects. The behavior of oximeters with malpositioned sensors during hypoxemia has not been studied. The current study is aimed at determining the behavior of several different pulse oximeters over a wide range of arterial oxygen saturation (SaO2).

METHODS

In each of 12 healthy volunteers, a radial artery cannula was inserted, and eight different pulse oximeters, five of which had malpositioned sensors, were applied. Subjects breathed controlled mixtures of nitrogen and oxygen to slowly vary their SaO2 from 100% to 70%. Arterial blood samples were analyzed and pulse oximeter data were recorded at five stable SaO2 values for each subject.

RESULTS

The oximeters with malpositioned sensors vary greatly in their behavior, depending on both the actual SaO2 and the manufacturer and model. One oximeter underestimated saturation at all SaO2 values, while three others underestimated at high SaO2 and overestimated at low SaO2. Linear regression analysis shows a decrease in the slope of SpO2 versus SaO2 in most cases, indicating a loss of sensitivity to SaO2 changes. Between-subject variation in response curves was significant.

CONCLUSIONS

The calibration curves of the pulse oximeters studied were changed greatly by sensor malpositioning. At low SaO2 values, these changes could cause the oximeter to indicate that a patient was only mildly hypoxemic when, in fact, hypoxemia was profound. It is recommended that sensor position be checked frequently and that inaccessible sensor locations be avoided whenever possible.

Influence of hydration on the internal dynamics of hen egg white lysozyme in the dry state

Proteins exist in a predominantly aqueous solvent environment. Hydration of the protein surface significantly affects many aspects of the protein's structure and function; these effects may be related to the molecular dynamics of the protein. We have examined the influence of hydration on the internal dynamics of hen egg white lysozyme using room-temperature phosphorescence from the intrinsic tryptophan residues. Powders of lyophilized lysozyme were hydrated in a phosphorimeter using a flow system that allowed for continuous manipulation of relative humidity over the range 0-92%; this system allowed us to directly compare intensity differences that result from changes in hydration. Lysozyme phosphorescence intensity decreased as a function of hydration over the entire relative humidity range; the decrease was not linear but appeared to occur in distinct phases. The phosphorescence intensity decays were multiexponential over the hydration range studied, and hydration had the largest influence on the long lifetime component. These data suggest that the protein exists in multiple, static conformations in the dry state and that water binding to polar (as opposed to charged) sites on the protein surface induces local and/or global softening of the protein structure.

Isoflurane versus fentanyl: hemodynamic effects in cancer patients treated with anthracyclines

Cancer patients treated with anthracycline derivatives are at risk for perioperative cardiovascular decompensation. The authors studied hemodynamic performance before, during, and after laparotomy in 14 anthracycline-treated patients with ovarian carcinoma. General anesthesia was maintained with 70% N2O in O2, and patients were randomized to receive supplementation with either isoflurane, 0.59% end-tidal +/- 0.04 (mean +/- SE), or fentanyl, 2.67 micrograms/kg +/- 0.49 as a loading dose, and a total dose of 7.16 micrograms/kg +/- 0.71. The degree of hemodynamic stability relative to the baseline was assessed. There was no obvious superiority of either technique prior to the skin incision. However, during and immediately after surgery, a clearer tendency for isoflurane-N2O to result in better hemodynamic stability was found. Isoflurane-N2O demonstrated significantly smaller change scores in systemic vascular resistance (SVR) and cardiac index (CI). At the start of surgery, the isoflurane-N2O change in SVR was 228.08 dyne.sec.cm-5 compared to 479.58 for the fentanyl patients, (P = 0.002); at the end of surgery the corresponding means were -12.09 and 703.14 dyne.sec.cm-5, respectively, (P = 0.002). Isoflurane-N2O was associated with significantly greater CI stability in the early postoperative period: the isoflurane-N2O mean change was -0.081 L/min/m2, versus -0.993 for the fentanyl-N2O patients, (P = 0.005). The authors conclude that anthracycline-treated patients who do not have overt evidence of cardiomyopathy can be safely anesthetized with either anesthetic technique. However, during surgery and in the early postoperative period, an isoflurane-N2O technique appears to offer better hemodynamic stability.

Chromosome abnormalities in patients treated with 4-hydroperoxycyclophosphamide-purged autologous bone marrow transplantation

Autologous bone marrow transplantation (ABMT) offers potentially curative therapy for patients with acute leukemia and lymphoma, yet little information exists about the chromosome abnormalities observed in ABMT recipients. Clonal abnormalities of chromosome 1 were reported by van den Akker. We report the cytogenetic results of 55 patients who underwent ABMT between November 1987 and July 1990: acute nonlymphocytic leukemia (ANLL, 22), acute lymphocytic leukemia (ALL, eight), Hodgkin's disease (seven), lymphoma (16), other (two). ANLL patients received busulfan and cytoxan, and the others received cytoxan and total body irradiation as their preparative regimen before transplant. BM was purged ex vivo with 4-hydroperoxycyclophosphamide (4-HC) at 30-100 micrograms/ml before reinfusion to kill tumor cells. Cytogenetic analysis was performed before and after transplant. Between one and four posttransplant specimens of BM were analyzed per patient (range 36-921 days). Chromosome abnormalities were observed in 14 of 55 patients after transplant. Seven had clonal abnormalities; all were in leukemic relapse, and one karyotype had complex rearrangements. Clonal abnormalities of chromosome 1 were not observed. Seven patients had nonclonal changes, and three of these have had overt clinical relapse. Our data suggest that clonal abnormalities observed posttransplant are best explained by clinical relapse of tumor and that ex vivo marrow purging with 4-HC is not likely to induce clonal chromosome abnormalities in normal cells. Long-term observation of these patients will be required to answer that question definitively, however.

Prediction equation estimates of creatinine clearance in the intensive care unit

OBJECTIVE

To assess the accuracy of 4 mathematical equations used to estimate creatinine clearance versus the 24-h creatinine clearance in ICU patients.

DESIGN

Prospective study of renal function prediction.

SETTING

The general adult ICUs of 3 metropolitan hospitals.

PATIENTS

199 critically ill patients with indwelling foley catheters.

INTERVENTION AND MEASUREMENTS

Routine 24 h creatinine clearances were evaluated only in patients whose urine volume recorded by the nurses was within 10% of the laboratory's measured volume. Four mathematical equations utilizing age, sex, body weight, height, and plasma creatinine were used as a comparison. There was no difference in estimated creatinine clearance by 3 published methods when the 24 h creatinine clearance exceeded 100 ml/min. When the 24 h creatinine clearance was less than 100 ml/min, however, one prediction equation adjusted for lean body weight (LBW), was the most accurate. This equation accurately predicted creatinine clearance in the range of 30-100 ml/min and slightly overestimated creatinine clearance at 0-30 ml/min (p < 0.01, ANOVA all groups, p < 0.05 Fisher and Scheffé post-hoc tests) with a mean difference +/- 95% confidence interval of -5 +/- 3.1 ml/min.

CONCLUSION

An initial rapid estimate of creatinine clearance in critically ill ICU patients with reduced renal function can be determined by an equation adjusted for LBW.

Karyotype at relapse following allogeneic bone marrow transplantation for chronic myelogenous leukemia

Eighty-four patients underwent allogeneic or syngeneic bone marrow transplantation as therapy for chronic myelogenous leukemia (CML) during a 5-year period at The Johns Hopkins Oncology Center. We describe the karyotype at relapse in 19 patients who were Ph chromosome positive (Ph+) at diagnosis. Eighty-four percent of patients demonstrated clonal and/or nonclonal chromosome abnormalities in addition to the t(9;22)(q34;q11) at first detection of relapse or later during relapse. These abnormalities included: Ph plus additional clonal abnormalities (three patients), Ph plus nonclonal abnormalities (five patients), Ph plus additional clonal and nonclonal abnormalities (eight patients). Three patients had only the original Ph+ clone. The additional chromosome abnormalities were primarily structural, and entirely different from those most frequently observed during karyotypic evolution in conventionally treated CML. Chromosome 1 was most frequently involved, with 1q32 being the location of three clonal and two nonclonal abnormalities. Other sites included 6p21-22 (the site of two clonal abnormalities), 7p21-22, and 10q21 (the site of two clonal and one nonclonal abnormality each). Chromosomes 5 and 7q, regions of frequent involvement in acute nonlymphocytic leukemia that follows chemotherapy for other malignancies, were infrequently involved. The clinical significance of these additional abnormalities remains undetermined at this time.

Spontaneous left ventricle cavity thrombus in a patient of systemic lupus erythematosus

A 32 year old female with systemic lupus erythematosus having circulating lupus anticoagulant developed a thrombus in the left ventricle cavity, an unusual site. She responded to standard anticoagulant regime.

A clinical evaluation of pulse oximetry during thoracic surgery

To evaluate the utility of pulse oximetry for monitoring oxygenation during thoracic surgery, pulse oximeter oxygen saturation (SpO2) values from the Nellcor N-100 (Nellcor Inc, Haywood, CA) and Novametrix model 500 (Medical Systems Inc, Wallingford, CT) were compared with simultaneous arterial saturation values (SaO2) in 20 patients. A total of 255 matched observations were recorded, and the data were divided for statistical analysis into preinduction of anesthesia and postinduction groups. The preinduction group showed a good correlation between SpO2 and SaO2 values, with both pulse oximeters consistently overestimating the SaO2. However, once anesthesia was induced, there was no longer any correlation for either of the pulse oximeters versus simultaneous SaO2 values, although on average, the SpO2 values were significantly higher than the corresponding SaO2 values. It was concluded that pulse oximetry is useful in following trends of oxygenation in patients with preexisting lung pathology undergoing thoracic surgery, but it cannot replace arterial blood gas sampling for the intraoperative management of respiratory function.

A comparison of EEG determinants of near-awakening from isoflurane and fentanyl anesthesia. Spectral edge, median power frequency, and delta ratio

To evaluate the efficacy of the computer-processed electro-encephalogram (EEG) for determining near-awakening from anesthesia, 14 patients were monitored during emergence from either isoflurane or fentanyl anesthesia at the termination of major surgical procedures. The raw EEG was obtained using bilateral frontomastoid electrodes. The compressed spectral array was digitized and recorded on disk in 4-s epochs using a Tractor Northern "Nomad" processor. The EEG information was displayed in four formats: 1) the frequency-power spectrum from 1-20 Hz, 2) the 95% power frequency, 3) the 50% power frequency, and 4) the ratio of power in the 8-20 Hz frequency range to the power in the 1-4 Hz frequency range (delta ratio). During emergence from isoflurane, there were obvious changes in the EEG frequency-power spectrum that occurred several minutes before patients opened their eyes in response to verbal stimuli. Although no one descriptor of EEG activity could be shown to be superior in anticipating when patients would respond by opening their eyes, awakening was always presaged by an abrupt decrease in power in the 1-4 Hz frequency range; this resulted in a marked increase in the delta ratio value. During emergence from fentanyl anesthesia, however, there was no obvious change in the overall EEG frequency-power spectrum. However, the same numeric EEG descriptors that were predictive of awakening from isoflurane also occurred during emergence from fentanyl, even though they usually occurred within 1 min of awakening. It is concluded that EEG criteria for identifying when patients will awaken from anesthesia are more reliable with isoflurane than with fentanyl.

Comparison of the Bain and the ADE systems during controlled ventilation in adults

It has been suggested that Humphrey's ADE system may be an improvement on the Bain system. To compare their efficiencies we have studied 20 anesthetized adults who had controlled ventilation established with a circle absorber system at a VE sufficient to maintain normocapnia. Patients were then randomly allocated to either a Bain or an ADE system. Fresh gas flow was sufficient to keep PE'CO2 constant for 30 min. The other circuit was then used for an additional 30 min. The required FGF was 54 ml kg-1 min-1 for the Bain system, compared with 67 ml kg-1 min-1 for the ADE system. We conclude that, during controlled ventilation, the ADE system is 25% less efficient than the Bain system.

Intraoperative measurement of cerebral and tumor blood flow with laser-Doppler flowmetry

A new technique, laser-Doppler flowmetry, has been used intraoperatively to measure blood flow responses in normal brain tissue and brain tumor to blood pressure and arterial blood gas alterations. We have observed that blood flow is reduced in most cerebral tumors, and that most tumors retain the normal response to changes in arterial blood gas; however, these responses are varied. One group of tumors in our study demonstrated an autoregulatory capacity; a second behaved passively--that is, blood flow changes followed blood pressure--while a third showed no response.

Histological evaluation of cutaneous wound healing in presence of nitrous oxide in rats

Three-centimetre linear incisions were made in 90 young male Lew/f Mai rats by scalpel through skin to the investing fascia of the left flank. The skin was undermined sharply for a distance of 0.5 cm along both sides of the entire length of the incision. The wound site was closed per primam with Michel clips and left uncovered. Following emergence from anesthesia, rats were randomly allocated to one of three groups of 30 rats each: one group breathed air only and acted as control; the second was exposed to 20% N2O for 24 hours daily until sacrificed (continuous group); the third was exposed to 20% N2O for 8 hours daily until sacrificed (intermittent group). Ten rats from each of the three groups were sacrificed after 3, 7, or 10 days postincision. After sacrifice, sections from the wound stained with hematoxylin and eosin or reticulin were examined microscopically. No histological evidence of an effect on wound healing of skin occurred in rats exposed to 20% N2O.

Autonomic hyperreflexia during cystoscopy in patients with high spinal cord injuries

Cystoscopic procedures were performed on 102 patients with histories of traumatic spinal cord lesion; 57 patients had sensorimotor levels above T7, and the remaining 45 patients had levels below T7. In 40 of the 57 patients (70 per cent) with levels above T7, signs and symptoms of autonomic hyperreflexia were seen during bladder distension and cystoscopy; the remaining 17 of these patients (30 per cent) did not have this response. No autonomic hyperreflexia was seen during cystoscopy in any of the 45 patients with sensorimotor levels below T7.

Naloxone antagonism after narcotic-supplemented anesthesia

Narcotic-supplemented balanced anesthesia is increasing in popularity; however, the narcotic must frequently be antagonized postoperatively. Authorities differ in their recommendations as to dose and as to mode and duration of administration of the narcotic antagonist. In the present study of 58 patients undergoing narcotic-supplemented anesthesia, 60 percent of 42 fentanyl patients and 81 percent of 16 morphine patients required postsurgical naloxone for respiratory inadequacy. Naloxone dosage was initially 1.5 mug/kg IV, with repeat IV doses of 1.5 mug/kg, when needed, at 3-minute intervals, until a regular respiratory rate greater than 15 breaths/min was attained. None of the fentanyl patients and only 25 percent (4/16) of the morphine patients required additional naloxone in the recovery room. For the latter, the dose of naloxone previously administered was given IM and proved satisfactory. Additional analgesia was needed by 12 percent (7/58) of the patients during the recovery room stay. Judicious naloxone titration permitted respiratory adequacy to coexist with analgesia after narcotic-supplemented anesthesia.

Testicular reaction to prolonged exposure to nitrous oxide

Male LEW/f Mai rats were exposed to an atmosphere of 20 per cent N2O, 20 per cent O2, and 60 per cent N2 for a maximum of 35 days. Evidence of injury to the seminiferous tubules was found in some animals by the second day. By 14 days, such damage was found in all animals. The toxic effect was confined to the spermatogenic cells, with consequent reduction in mature spermatozoa and appearance of multinucleated forms. Other cells within the testes were resistant to damage. Recovery of spermatogenesis occurred after return to room air for more than three days. Serum testosterone levels were not significantly affected during the prolonged exposure.

Hodgkin's disease in children

From 1921 to 1973, 106 children with Hodgkin's disease under the age of 17 years were seen at Roswell Park Memorial Institute and were analyzed retrospectively. Evaluation was separated into three eras: 1921-1949 (early era), 1950-1964 (middle era), and 1965-1973 (recent era). In the early era, suboptimal radiation therapy was employed. In the middle era, radiation therapy techniques were improved, and single-agent chemotherapy was introduced. In the recent era, multiagent chemotherapy routines were frequently used; aggressive external megavoltage radiation therapy became routine in conjunction with improvement in staging procedures. The best survival was observed in the recent era where five-year survival of 96% was noted in early stage disease. Favorable prognostic features included: younger age group (5-9 years), female sex, lymphocytic predominant histology, early stage disease, and complete response to therapy. Nodular sclerosing and mixed cell types had an equal prognosis. The concept of involved area radiotherapy along with combination chemotherapy appears a reasonable approach in children and should be tested in a randomized study against more extensive radiotherapy techniques in early stage disease.