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).

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.

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.

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.