Tolerability of four-drug antiretroviral combination therapy in primary HIV-1 infection

Objectives

Rapid initiation of antiretroviral therapy (ART) is important for individuals with high baseline viral loads, such as in primary HIV‐1 infection (PHI). Four‐drug regimens are sometimes considered; however, data are lacking on tolerability. We aimed to evaluate the tolerability of four‐drug regimens used in the Research in Viral Eradication of HIV‐1 Reservoirs (RIVER) study.

Methods

At enrolment, ART‐naïve adult participants or those newly commenced on ART were initiated or intensified to four‐drug regimens within 4 weeks of PHI. Rapid start was defined as pre‐confirmation or ≤ 7 days of confirmed diagnosis. Primary and secondary outcomes were patient‐reported adherence measured by 7‐day recall and regimen switches between enrolment and randomization, respectively.

Results

Overall, 54 men were included: 72.2% were of white ethnicity, with a median age of 32 years old, 42.6% had a viral load of ≥ 100 000 HIV‐1 RNA copies/mL, and in 92.6% sex with men was the mode of acquisition of HIV‐1. Twenty (37%) started a four‐drug regimen and 34 (63%) were intensified. Rapid ART initiation occurred in 28%, 100% started in ≤ 4 weeks. By weeks 4, 12, and 24, 37.0%, 69.0%, and 94.0% were undetectable (viral load < 50 copies/mL), respectively. Adherence rates of 100% at weeks 4, 12, 22 and 24 were reported in 88.9%, 87.0%, 82.4% and 94.1% of participants, respectively. Five individuals switched to three drugs, four changed their regimen constituents, and two switched post‐randomization.

Conclusions

Overall, four‐drug regimens were well tolerated and had high levels of adherence. Whilst their benefit over three‐drug regimens is lacking, our findings should provide reassurance if a temporarily intensified regimen is clinically indicated to help facilitate treatment.

Addendum to the IPEMB code of practice for the determination of absorbed dose for x-rays below 300 kV generating potential (0.035 mm Al-4 mm Cu HVL)

This addendum to the code of practice for the determination of absorbed dose for x-rays below 300 kV has recently been approved by the IPEM and introduces three main changes: (i) Due to a lack of available data the original code recommended a value of unity for k(ch) in the very-low-energy range (0.035-1.0 mm Al HVL). A single table of k(ch) values, ranging from 1.01 to 1.07, applicable to both designated chamber types is now presented. (ii) For medium-energy x-rays (0.5-4 mm Cu HVL) methods are given to determine the absorbed dose to water either at 2 cm depth or at the surface of a phantom depending on clinical needs. Determination of the dose at the phantom surface is derived from an in-air measurement and by extending the low-energy range up to 4 mm Cu HVL. Relevant backscatter factors and ratios of mass energy absorption coefficients are given in the addendum. (iii) Relative dosimetry: although not normally forming part of a dosimetry code of practice a brief review of the current literature on this topic has been added as an appendix. This encompasses advice on techniques for measuring depth doses, applicator factors for small field sizes, dose fall off with increasing SSD and choice of appropriate phantom materials and ionization chambers.

Serologic evidence for West Nile virus infection in birds in the New York City vicinity during an outbreak in 1999

As part of an investigation of an encephalitis outbreak in New York City, we sampled 430 birds, representing 18 species in four orders, during September 13-23, 1999, in Queens and surrounding counties. Overall, 33% were positive for West Nile (WN) virus-neutralizing antibodies, and 0.5% were positive for St. Louis encephalitis virus-neutralizing antibodies. By county, Queens had the most seropositive birds for WN virus (50%); species with the greatest seropositivity for WN virus (sample sizes were at least six) were Domestic Goose, Domestic Chicken, House Sparrow, Canada Goose, and Rock Dove. One sampled bird, a captive adult Domestic Goose, showed signs of illness; WN virus infection was confirmed. Our results support the concept that chickens and House Sparrows are good arbovirus sentinels. This study also implicates the House Sparrow as an important vertebrate reservoir host.

The weaning continuum use of Acute Physiology and Chronic Health Evaluation III, Burns Wean Assessment Program, Therapeutic Intervention Scoring System, and Wean Index scores to establish stages of weaning

OBJECTIVE

To determine whether four stages of weaning (acute, prewean, wean, and outcome) could be identified by using clinical instruments designed to quantify severity of illness, patient stability, or weaning readiness. The instruments used were the Acute Physiology and Chronic Health Evaluation (APACHE III), the Therapeutic Intervention Scoring System (TISS), the Burns Wean Assessment Program (BWAP), and the Wean Index (WI). The stages were adapted from those proposed by the American Association of Critical Care Nurses Third National Study Group's Weaning Continuum Model.

DESIGN

Prospective, convenience cohort. This study was part of a larger study designed to test an outcomes managed approach to weaning by using an outcomes manager and a clinical pathway.

SETTING

University medical intensive care unit.

PATIENTS

Adult patients requiring mechanical ventilation >3 days admitted to the medical intensive care unit between November 1994 and May 1995.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Scores for the APACHE III, TISS, BWAP, and WI were collected on 97 patients every other day until they weaned, were transferred, or died. Outcomes described for each stage of weaning were dated on the clinical pathway when achieved. Comments about patient stability and ventilator progress also were recorded along with a subjective determination of the stage of weaning. We used decision rules to identify time intervals for each stage of weaning and outcomes attained by stage. Finally, APACHE III, TISS, BWAP, and WI scores were placed in each stage by date for analysis. The APACHE III, TISS, and BWAP scores were able to differentiate the acute, prewean, and wean stages but not the outcome stage.

CONCLUSIONS

By identifying distinct scores for each stage, we may be able to better explore appropriate interventions for the stages as well as predict weaning outcomes. Indices that include physiologic and respiratory factors can differentiate weaning stages, but respiratory factors alone cannot.

Inverse relationship between the expression of the human papillomavirus type 16 transcription factor E2 and virus DNA copy number during the progression of cervical intraepithelial neoplasia

The human papillomavirus type 16 (HPV-16) status of 43 cervical biopsies, which had been characterized histologically as normal, various grades of cervical intraepithelial neoplasia (CIN) and invasive squamous cell carcinoma, was examined by using (i) a novel antibody against the HPV-16 E2 protein, (ii) sensitive HPV-16 DNA in situ hybridization and (iii) microdissection/PCR for the E2 ORF. The data indicate that E2 protein expression is highest in koilocytes in lower-grade CIN (I), but decreases with increasing grade, whereas the detection of HPV DNA is delayed until CIN I/II, rising to the highest levels in carcinoma cells. Co-localization of E2 with HPV-16 DNA-positive cells was most commonly observed in koilocytes in CIN II lesions. PCR analyses of microdissected epithelium from the same or serial sections indicated that E2 ORFs were retained in an intact form in a number of higher-grade CIN lesions and invasive carcinomas.

Flight muscle resting potential and species-specific differences in chill-coma

Resting potentials in Apis mellifera and Drosophila melanogaster flight muscles decrease with falling temperatures. When resting potentials fall to between -37 and -45 mV they activate a final burst of spontaneous muscle action potentials (MAPs). This final burst of MAPs marks the beginning of chill-coma for each species. The temperature at which the final burst occurs for D. melanogaster (7.0+/-0.9 degrees C) is significantly lower than that of A. mellifera workers (10.6+/-1.2 degrees C), queens (10.2+/-0.8 degrees C), and drones (12.8+/-0.8 degrees C). Prior to chill-coma, MAP amplitudes decrease and durations increase with falling temperatures in both A. mellifera and D. melanogaster. The rate of these changes and the temperatures at which they occur appear to be related to the rate of decline in each species' resting potential. These results suggest that insect chill-coma varies with a species' ability to maintain its resting potential at low temperatures.

Transthoracic three-dimensional echocardiography in the preoperative assessment of atrioventricular septal defect morphology

A prospective study of 3-dimensional (3-D) transthoracic echocardiographic definition of atrioventricular septal defect (AVSD) morphology and its dynamic changes during the cardiac cycle was performed. The information obtained from 2-D and 3-D transthoracic echocardiography (TTE) was compared with intraoperative findings in an unselected group of 15 patients with AVSD (median age 22 months). In all study patients, 3-D reconstructions provided anatomic views of the atrioventricular valve(s) en face from either atrial or ventricular perspectives that allowed comprehensive assessment of dynamic valve morphology and the mechanism of valve reflux. Left-sided valve function was correctly assessed by 2-D TTE in 11 of 15 patients (73%) and in 14 of 15 (93%) by 3-D TTE. In 6 of 15 patients (40%), the severity of right-sided valve reflux was described precisely by 2-D TTE and in 12 of 15 patients (80%) by 3-D TTE. Additionally, 3-D TTE supplemented the diagnostic information to that available from 2-D TTE on atrial and ventricular septal defects. Although primum atrial septal defects were depicted by 2-D and 3-D TTE in all 15 patients, the description of defect size was more precise by the 3-D TTE (80% vs. 100%, respectively). The presence of secundum atrial septal defect was correctly diagnosed by both TTE techniques in 10 of 15 patients. Disagreement regarding the size of the defect was present only in 2 of 10 patients by 2-D TTE. In another 2 patients, 3-D TTE described multiple defect fenestrations that were missed by 2-D TTE. Thus, the agreement score was 73% for 2-D and 100% for 3-D echo. The agreement for the presence and sizing of ventricular septal defects was 67% for 2-D and 93% for 3-D echo. We conclude that 3-D TTE provided accurate anatomic reconstructions of the common atrioventricular junction and that the use of dynamic 3-D TTE enhanced the anatomic diagnostic capability of standard 2-D TTE. Medica, Inc.

Structure of the intact transactivation domain of the human papillomavirus E2 protein

Papillomaviruses cause warts and proliferative lesions in skin and other epithelia. In a minority of papillomavirus types ('high risk, including human papillomaviruses 16, 18, 31, 33, 45 and 56), further transformation of the wart lesions can produce tumours. The papillomavirus E2 protein controls primary transcription and replication of the viral genome. Both activities are governed by a approximately 200 amino-acid amino-terminal module (E2NT) which is connected to a DNA-binding carboxy-terminal module by a flexible linker. Here we describe the crystal structure of the complete E2NT module from human papillomavirus 16. The E2NT module forms a dimer both in the crystal and in solution. Amino acids that are necessary for transactivation are located at the dimer interface, indicating that the dimer structure may be important in the interactions of E2NT with viral and cellular transcription factors. We propose that dimer formation may contribute to the stabilization of DNA loops which may serve to relocate distal DNA-binding transcription factors to the site of human papillomavirus transcription initiation.

Persistent pulmonary hypertension of the newborn associated with pulmonary atresia and intact interventricular septum

Neonates with pulmonary atresia and intact interventricular septum (PAIVS) do not have pulmonary vascular disease secondary to their heart abnormality. Persistent pulmonary hypertension of the newborn has not been described in association with this condition. The case is reported of a female neonate born with PAIVS, who preoperatively had no clinical evidence or any risk factors for persistent pulmonary hypertension of the newborn, but whose postoperative course was highly suggestive of persistent pulmonary hypertension; necropsy confirmed the features of pulmonary vascular disease.

Postneonatal circumcision with local anesthesia: a cost-effective alternative

PURPOSE

Despite the controversy regarding the need for routine neonatal circumcision, most boys in the United States are circumcised. Physicians are commonly asked to perform circumcision after the neonatal period and are often unaware of the cost factors related to the timing and location of postneonatal circumcision.

MATERIALS AND METHODS

We describe the medical and financial advantages of postneonatal circumcision with local versus general anesthesia.

RESULTS

During a 30-month period 245 boys 6 months to 15 years old underwent circumcision under general anesthesia in the operating room. Hospital charges (facility and equipment) averaged $1,555 and anesthesia charges averaged $250. Therefore, the average cost for circumcision in the operating room was $1,805. During the same time period 287 infants 3 days to 9 months old (20% older than 3 months) underwent circumcision under local anesthesia in an office setting. The facility and equipment charge for these office procedures averaged $196. Overall, approximately $461,783 were saved in this 30-month period ($184,713 annually) by performing circumcision with local anesthesia in an office setting rather then in the operating room with general anesthesia. There was no significant difference in complication rates between the local and general anesthesia groups (1.4 versus 1.6%).

CONCLUSIONS

Circumcision with local anesthesia can be performed easily and safely during the first several months of life and has many advantages. Parents prefer this method because it is more convenient and eliminates the risk of general anesthesia. The enormous cost savings using local as opposed to general anesthesia should prompt a reexamination of the location and timing of postneonatal circumcision.

Absorbed-dose calibrations in high-energy photon beams at the National Physical Laboratory: conversion procedure

The absorbed-dose calibration service from NPL is based on a primary-standard calorimeter that measures absorbed dose to graphite. Secondary-standard dosemeters are calibrated in absorbed dose to water in a 60Co gamma-ray beam and in x-ray beams over a range of generating potentials from 4 MV to 19 MV. Two methods were used to convert the calibrations of working-standard ionization chambers from absorbed dose to graphite into absorbed dose to water. One method involved the use of published interaction data for photons and secondary electrons, and required a knowledge of the chamber construction. The second method involved the calculation of the ratio of absorbed dose in graphite and water phantoms irradiated consecutively in the same photon beam using the photon-fluence scaling theorem. The two methods were in agreement to 0.1%.

Radiographic exposure slide rules

Before automatic exposure control was fitted to diagnostic X-ray sets, radiographers were faced with the problem of choosing the parameters that would give the best radiographic image. For a new X-ray set whose performance was unknown, this was no easy matter, and often required considerable trial and error because of the number of variables involved. To reduce the amount of work, special slide rules were invented which calculated the effect of some of these variables. Five such slide rules, dating from between about 1910 and 1950, are illustrated and discussed, including the light they shed on changes in radiographic practice over the years.

Expression, crystallization and preliminary X-ray analysis of the E2 transactivation domain from papillomavirus type 16

The N-terminal transactivation domain of the E2 protein from human papillomavirus type 16 has been crystallized by vapour diffusion. Crystals belong to the space group P3121 (or P3221) with unit-cell dimensions a = b = 54.3, c = 155.5 A. There is one molecule per asymmetric unit with a solvent content of 55%. Crystals diffract to at least 2.5 A resolution and complete X-ray data to 3.4 A have been collected on a conventional laboratory source. This 201 amino-acid domain of the E2 protein has been shown to interact functionally with both the HPV E1 protein and at least three cellular transcription factors, to fulfil its role in the control of viral transcription and replication. A knowledge of the structural basis of these multiple interactions should lead to a fuller understanding of the mechanism of action of this key regulator of the HPV life cycle.

Expression patterns of the human papillomavirus type 16 transcription factor E2 in low- and high-grade cervical intraepithelial neoplasia

Specific antibodies against the C-terminus of E2, produced by affinity purification of polyclonal antisera, have been used to identify the cellular populations which express the HPV 16 E2 transcription factor, in a series of formalin-fixed, paraffin-embedded cervical tissues. Cases were selected for both the presence of HPV 16 DNA (confirmed by multiple gene-specific PCR detections) and the presence of multiple grades of cervical intraepithelial neoplasia (CIN). The data indicate that E2 expression is highest in CIN I and in koilocytic lesions. Lower expression was observed in CIN II and little in CIN III lesions. In contrast, there was some restoration of E2 expression in invasive carcinomas, although the intracellular distribution was much more diffuse. The location of E2 expression to the superficial layers of the cervical epithelium, as well as the occurrence of some basal expression in CIN I, suggests that antibodies against HPV 16 E2 could be a useful adjunct to standard histological techniques for the detection of 'at-risk' patients as part of a cervical screening programme.

Race and delayed kidney allograft function

BACKGROUND

Allograft survival among black recipients is poorer than among whites. Delayed allograft function is associated with a significant reduction in renal allograft survival. The relationship between delayed allograft function and black race is incompletely specified and was the focus of this investigation.

METHODS

A non-concurrent study of 325 recipients of cadaveric allografts followed for the occurrence of delayed allograft function defined as dialysis during the first week following transplantation for the principal analysis. A secondary definition of delayed allograft function was formulated based on the serum creatinine 2 weeks after transplantation. Unadjusted and adjusted logistic regression analysis were used to examine the unconfounded relationship between race and delayed allograft function.

RESULTS

Fifty-seven of 91 (62.6%) black recipients experienced delayed allograft function compared to 113 of 234 (48.3%) whites. The odds ratio for black race as a predictor of delayed allograft function was 1.80, P=0.02, (95% CI, 1.09, 2.95). This finding was stable despite adjustment for other predictors of delayed allograft function in a multivariate model, but the precision of this estimate was less (P=0.10) because of missing data. Additionally, adjusted models with imputed values for missing covariates, models using a secondary definition of delayed allograft function, and models excluding patients whose cyclosporin therapy was delayed, all consistently demonstrated a similar association between black race and delayed allograft function.

CONCLUSIONS

This study demonstrated an increased risk of delayed allograft function among black recipients. This relationship may play a role in the poorer allograft outcomes experienced by black recipients. Given the negative effect of delayed allograft function on allograft survival, efforts to identify its modifiable risk factors should be a high priority.

Design, testing, and results of an outcomes-managed approach to patients requiring prolonged mechanical ventilation

BACKGROUND: Outcomes management that uses critical pathways may decrease costs while improving outcomes for patients who require prolonged mechanical ventilation. OBJECTIVE: To study the efficacy of an outcomes-managed approach to weaning patients from prolonged (more than 3 days) mechanical ventilation. METHODS: A method of multidisciplinary care delivery was designed that included an outcomes manager, a care pathway for patients receiving mechanical ventilation, and weaning protocols. Data collection consisted of three parts: a retrospective review of 124 patients who required prolonged ventilation during a 1-year period before implementation of the care model, a 6-month prospective study in which 91 patients were alternately assigned by month to an outcomes-managed approach or a non-outcomes-managed approach, and a 6-month prospective study of 90 patients in which an outcomes-managed approach without alternate-month assignment was used. RESULTS: Outcomes management had no significant effect on total duration of mechanical ventilation or length of stay in the hospital, days of mechanical ventilation without tracheostomy, days of mechanical ventilation with tracheostomy, or outcome (weaned, withdrawal from mechanical ventilation, death, or transfer without weaning). However, duration of mechanical ventilation was 1.3 days shorter, length of stay in the hospital was 2.1 days shorter, and the cost per case was $ 3341 less for patients in the outcomes-managed group than for patients in the non-outcomes-managed group. CONCLUSION: Outcomes-managed care did not have a significant effect on duration of ventilation, length of stay in the hospital, or outcome in patients receiving long-term mechanical ventilation.

Design, testing, and results of an outcomes-managed approach to patients requiring prolonged mechanical ventilation

BACKGROUND

Outcomes management that uses critical pathways may decrease costs while improving outcomes for patients who require prolonged mechanical ventilation.

OBJECTIVE

To study the efficacy of an outcomes-managed approach to weaning patients from prolonged (more than 3 days) mechanical ventilation.

METHODS

A method of multidisciplinary care delivery was designed that included an outcomes manager, a care pathway for patients receiving mechanical ventilation, and weaning protocols. Data collection consisted of three parts: a retrospective review of 124 patients who required prolonged ventilation during a 1-year period before implementation of the care model, a 6-month prospective study in which 91 patients were alternately assigned by month to an outcomes-managed approach or a non-outcomes-managed approach, and a 6-month prospective study of 90 patients in which an outcomes-managed approach without alternate-month assignment was used.

RESULTS

Outcomes management had no significant effect on total duration of mechanical ventilation or length of stay in the hospital, days of mechanical ventilation without tracheostomy, days of mechanical ventilation with tracheostomy, or outcome (weaned, withdrawal from mechanical ventilation, death, or transfer without weaning). However, duration of mechanical ventilation was 1.3 days shorter, length of stay in the hospital was 2.1 days shorter, and the cost per case was $ 3341 less for patients in the outcomes-managed group than for patients in the non-outcomes-managed group.

CONCLUSION

Outcomes-managed care did not have a significant effect on duration of ventilation, length of stay in the hospital, or outcome in patients receiving long-term mechanical ventilation.

Are frequent inner cannula changes necessary?: A pilot study

OBJECTIVE

To determine the incidence of obstruction and colonization in adult patients in the surgical and medical intensive care units who received inner cannula changes daily versus those who did not.

DESIGN

Quasi-experimental prospective study using a convenience sample of patients randomly assigned to one of two methods.

SETTING

Mid-Atlantic university-affiliated tertiary care center.

PATIENTS

Sixty patients within 24 hours of receiving a surgical tracheostomy.

OUTCOME MEASURES

Obstruction and bacterial colonization of inner cannula.

INTERVENTIONS

All inner cannulas were checked daily for obstruction and cultured on postoperative days 1 and 3.

RESULTS

No statistically significant difference was noted in colonization (p = 0.13) between protocols, and no obstructions were noted in either.

CONCLUSION

The study suggests that the routine practice in critical care units of changing tracheostomy inner cannulas may be unnecessary. Although the results of this study are limited, and may not be generalized to other populations, it demonstrates that practice standards related to the care of tracheostomy inner cannula need to be challenged.

Single-chain Fv fragments of anti-neuraminidase antibody NC10 containing five- and ten-residue linkers form dimers and with zero-residue linker a trimer

Single-chain variable fragments (scFvs) of anti-neuraminidase antibody NC10 were constructed by joining the VH and VL domains with 10-residue (Gly4Ser)2 and five-residue (Gly4Ser) linkers; a zero-residue linker scFv was constructed by joining the C-terminal residue of the VH domain to the N-terminus of the VL domain. The scFv with the 10- and five-residue linkers exclusively formed dimeric antibody fragments (M(r) 52000). These were shown to be bivalent and were able to cross-link two neuraminidase tetramers to form a 'sandwich' type complex; each antigen combining site could also bind an anti-idiotype Fab'. The zero-residue linker scFv (M(r) 70000) was shown to form a trimer with three active antigen combining sites, each binding an anti-idiotype Fab' to yield a complex of M(r) 212000. The orientation of the combining sites in the zero-residue linker scFv, however, was such that it could not cross-link tetramers of neuraminidase. BIAcore biosensor experiments showed that the affinity of each individual antigen combining site in both the 10- and five-residue linker scFv dimers and zero-residue linker scFv trimer was essentially the same when the scFvs were immobilized onto the sensor surface. However, when the scFvs were used as the analyte, the dimeric and trimeric scFvs showed an apparent increase in binding affinity due to the avidity of binding the multivalent scFvs.

Delayed function reduces renal allograft survival independent of acute rejection

BACKGROUND

Mechanisms by which delayed allograft function reduces renal allograft survival are poorly understood. This study evaluated the relationship of delayed allograft function to acute rejection and long-term survival of cadaveric allografts.

METHODS

338 recipients of cadaveric allografts were followed until death, resumption of dialysis, retransplantation, loss to follow-up, or the study's end, which ever came first. Delayed allograft function was defined by dialysis during the first week following transplantation. Multivariate Cox proportional hazards survival analysis was used to assess the relationship of delayed allograft function to rejection and allograft survival.

RESULTS

Delayed allograft function, recipient age, preformed reactive antibody levels, prior kidney transplantation, recipient race, rejection during the first 30 days and rejection subsequent to 30 days following transplantation were predictive of allograft survival in multivariate survival models. Delayed allograft function was associated with shorter allograft survival after adjustment for acute rejection and other covariates (relative rate of failure [RR]+1.72 [95% CI, 1.07, 2.76]). The adjusted RR of allograft failure associated with any rejection during the first 30 days was 1.99 (1.23, 3.21), and for rejection subsequent to the first 30 days was 3.53 (2.9 08, 6.00). The impact of delayed allograft function did not change substantially (RR=1.84 [1.15, 2.95]) in models not controlling for acute rejection. These results were stable among several subgroups of patients and using alternative definitions of allograft survival and delayed allograft function.

CONCLUSIONS

This study demonstrates that delayed allograft function and acute allograft rejection have important independent and deleterious effects on cadaveric allograft survival. These results suggest that the effect of delayed allograft function is mediated, in part, through mechanisms not involving acute clinical rejection.

Recipient body size and cadaveric renal allograft survival

Transplantation of renal allografts inadequate to meet recipient metabolic demands has been hypothesized to be one cause of chronic allograft failure. This cohort study examined the relationship of each of three measures of recipient body size and one measure of recipient metabolic rate to the rate of allograft failure among 239 recipients of cadaveric renal allografts between 1985 and 1990. All subjects were followed until allograft failure, death, or December 31, 1992, whichever occurred first. Using multivariate Cox proportional hazards analysis, all measures of recipient size and metabolic rate were found to be strong and statistically significant predictors of allograft survival adjusted for other predictors of allograft survival including allograft rejection, delayed allograft function, recipient race, prior renal transplantation, and donor age. The adjusted relative risk (RR) of allograft failure for a 15-kg increase in recipient body weight was 1.47, P < 0.0001 (95% confidence interval (CI), 1.21-1.78); adjusted RR for a 10-U increase in recipient body mass index was 2.34, P < 0.0001 (95% CI, 1.53-3.58); adjusted RR for a 0.5 m2 increase in recipient body surface area was 2.34, P < 0.001 (95% CI, 1.40-3.91); and adjusted RR for a 250 Kcal increase in metabolic rate was 1.49, P < 0.01 (95% CI, 1.17-1.89). These results are consistent with prior research indicating that a renal tissue supply-demand mismatch may accelerate failure of renal allografts. Alternative explanations of this relationship between recipient body size and allograft survival include inadequate immunosuppressive medication administration among recipients with a larger body size. Additional research is warranted to examine more fully the relationship between recipient body size and allograft survival.

Movement and force produced by a single myosin head

Muscle contraction is driven by the cyclical interaction of myosin with actin, coupled to the breakdown of ATP. Studies of the interaction of filamentous myosin and of a double-headed proteolytic fragment, heavy meromyosin (HMM), with actin have demonstrated discrete mechanical events, arising from stochastic interaction of single myosin molecules with actin. Here we show, using an optical-tweezers transducer, that a single myosin subfragment-1 (S1), which is a single myosin head, can act as an independent generator of force and movement. Our analysis accounts for the broad distribution of displacement amplitudes observed, and indicates that the underlying movement (working stroke) produced by a single acto-S1 interaction is approximately 4 nm, considerably shorter than previous estimates but consistent with structural data. We measure the average force generated by S1 or HMM to be at least 1.7 pN under isometric conditions.

Comparison of nasogastric tube securing methods and tube types in medical intensive care patients

BACKGROUND: Nasogastric tube displacement can result in serious complications such as aspiration and inadvertent migration of the tube into the lungs. Replacement of the tubes is costly, time- and effort-intensive, uncomfortable for the patients, and potentially dangerous. OBJECTIVE: To determine the best of three methods for securing nasogastric tubes in a medical intensive care population and to identify variables related to the failure of tube securing methods. METHODS: A convenience sample of 103 patients requiring duodenal or standard gastric tubes for feeding, medication delivery, or decompression were randomly assigned to one of three taping methods: pink tape, clear tape, or "butterfly," for a total of 264 taping episodes. Data collection included the mean time until failure of the securing methods as well as variables such as patient alertness and mobility. RESULTS: The mean time until failure was 100 hours with pink tape versus 56 hours with clear tape and 30 hours with the "butterfly." Differences were significant. Duodenal tubes stayed secured longer than standard sump tubes (mean time until failure was 86 vs 41 hours) for all taping methods, but not significant relationship was demonstrated between mean time until failure and variables such as alertness, sedation, confusion, mobility, and the use of restraints. CONCLUSION: Our results showed that the pink tape method was superior. Nasogastric tube securing methods in adult critical care patients vary in efficacy and should be selected carefully.

Comparison of nasogastric tube securing methods and tube types in medical intensive care patients

BACKGROUND

Nasogastric tube displacement can result in serious complications such as aspiration and inadvertent migration of the tube into the lungs. Replacement of the tubes is costly, time- and effort-intensive, uncomfortable for the patients, and potentially dangerous.

OBJECTIVE

To determine the best of three methods for securing nasogastric tubes in a medical intensive care population and to identify variables related to the failure of tube securing methods.

METHODS

A convenience sample of 103 patients requiring duodenal or standard gastric tubes for feeding, medication delivery, or decompression were randomly assigned to one of three taping methods: pink tape, clear tape, or "butterfly," for a total of 264 taping episodes. Data collection included the mean time until failure of the securing methods as well as variables such as patient alertness and mobility.

RESULTS

The mean time until failure was 100 hours with pink tape versus 56 hours with clear tape and 30 hours with the "butterfly." Differences were significant. Duodenal tubes stayed secured longer than standard sump tubes (mean time until failure was 86 vs 41 hours) for all taping methods, but not significant relationship was demonstrated between mean time until failure and variables such as alertness, sedation, confusion, mobility, and the use of restraints.

CONCLUSION

Our results showed that the pink tape method was superior. Nasogastric tube securing methods in adult critical care patients vary in efficacy and should be selected carefully.

Single-molecule mechanics of heavy meromyosin and S1 interacting with rabbit or Drosophila actins using optical tweezers

Single-molecule mechanical interactions between rabbit heavy meromyosin (HMM) or subfragment 1 (S1) and rabbit actin were measured with an optical tweezers piconewton, nanometer transducer. Similar intermittent interactions were observed with HMM and S1. The mean magnitude of the single interaction isotonic displacements was 20 nm for HMM and 15 nm with S1. The mean value of the force of single-molecule interactions was 1.8 pN for HMM and 1.7 pN with S1. The stiffness of myosin S1 was determined by applying a sinusoidal length change to the thin filament and measuring the corresponding force; the mean stiffness was 0.13 pN nm-1. By moving an actin filament over a long distance past an isolated S1 head, we found that cross-bridge attachment occurred preferentially at a periodicity of about 40 nm, similar to that of the actin helical repeat. Rate constants for the probability of detachment of HMM from actin were determined from histograms of the lifetime of the attached state. This gave a value of 8 s-1 or 0.8 x 10(6) M-1 s-1 for binding of ATP to the rigor complex. We conclude (1) that our HMM-actin interactions involve just one head, (2) that compliance of the cross-bridge is not in myosin subfragment 2, although we cannot say to what extent contributions arise from myosin S1 or actin, and (3) that the elemental movement can be caused by a change of shape of the S1 head, but that this would have to be much greater than the movements suggested from structural studies of S1 (Rayment et al., 1993).

Purification of the extracellular acidic proteases of Dichelobacter nodosus

Dichelobacter nodosus, a Gram negative obligate anaerobe and causative organism of ovine footrot, secretes a family of extracellular acidic serine proteases with pI's in the range of 5.2 to 5.6, and a basic serine protease with a pI of approximately 9.5. Four acidic proteases (V1, V2, V3 and V5) from virulent and five acidic proteases (B1 to B5) from benign strains of D. nodosus were purified by chromatography on Sephadex G-100 and DEAE-Sepharose CL-6B. Proteases V2, V5 and B5 were found to yield two forms (a and b) on purification which probably arise from limited autolysis of the parent molecule. Amino acid compositions, peptide profiles produced on autolysis and apparent Mr on SDS-PAGE of proteases V1-V3 showed that they were similar to each other and to proteases B1 to B4, and that these proteases were clearly distinct from proteases V5 and B5, which were found to be identical.

The p53 status of cultured human premalignant oral keratinocytes

Around 60% of oral squamous cell carcinomas (SCCs) have been shown to harbour p53 mutations, and other studies have demonstrated mutant p53 genes in normal and dysplastic squamous epithelium adjacent to these SCCs. In line with these earlier studies we show here that DOK, a keratinocyte cell line derived from a dysplasia, displays elevated levels of p53 protein and harbours a 12 bp in-frame deletion of the p53 gene spanning codons 188-191. In contrast, the coding region of the p53 gene was normal in a series of six benign recurrent laryngeal papillomas and a series of four premalignant oral erythroplakia biopsies and their cell cultures. All but one of these lesions were free of malignancy at the time of biopsy, in contrast to the premalignant lesions studied by previous investigators, but keratinocytes cultured from these lesions all displayed a partially transformed phenotype that was less pronounced than that of DOK. Since three out of four of the erythroplakia patients developed SCC within 1 year of biopsy, these lesions were by definition premalignant. The availability of strains of partially transformed keratinocytes from premalignant erythroplakias which possess normal p53 genes should enable us to test the role of mutant p53 in the progression of erythroplakia to SCC. The premalignant tissues and cultures were also tested for the presence of human papillomavirus (HPV), which is known to inactivate p53 function in some cases. Only the benign papillomas were shown to contain high levels of either HPV 6 or HPV 11 E6 DNA, but not both, and none of the samples contained detectable levels of HPV 16, HPV 18 or HPV 33 E6 DNA or L1 DNA of several other HPV types. There was therefore no evidence to suggest that p53 was being inactivated by a highly oncogenic HPV in these samples.

Comparison of five clinical weaning indices

BACKGROUND

Despite extensive data acquired in the area of weaning, clinicians still struggle with the questions of how and when to begin the process. Clinical weaning indices, designed to predict weaning potential, are often difficult to use. They provide an answer at a specific time; extrapolation to the weaning process is rarely possible. No single index has proven to be superior.

OBJECTIVES

To test the efficacy of five clinical weaning indices (Burns Weaning Assessment Program; Weaning Index; frequency tidal volume ratio; compliance, resistance, oxygenation and pressure index; and negative inspiratory pressure) at regular intervals during withdrawal of ventilatory support and to determine threshold levels for the program.

METHODS

A prospective convenience sample consisted of 37 adult critical care patients requiring mechanical ventilation for at least 7 days and identified as stable and ready to wean. Data were collected on all weaning indices every other day until the patient was weaned.

RESULTS

With the exception of the Burns Weaning Assessment Program, weaning indices did not change significantly from preweaning scores. Furthermore, the results failed to demonstrate that any of the five clinical weaning indices have strong predictive power related to weaning trial outcomes, although all the indices had negative predictive values that may be helpful in predicting unsuccessful weaning trials.

CONCLUSIONS

The results of this study suggest that the process of weaning may be enhanced by comprehensive, systematic approaches and that clinical weaning indices like the Burns Weaning Assessment Program might best serve as tools to track trends in progress, keep care planning on target, and prevent unsuccessful weaning trials.

Hydrops foetalis and chylothorax associated with superior caval vein obstruction and resolution following balloon dilatation

A female infant (33 weeks' gestation) was delivered by emergency caesarean section because of hydrops foetalis. No cause was identified initially; haemoglobin, liver and renal functions were normal and there was no evidence of sepsis or significant myocardial dysfunction or arrhythmia. There was initial improvement with conventional management but bilateral pleural effusions persisted, which became overtly chylous after institution of enteral formula feeds on day 4. At 5 weeks of age, an obstruction at the superior caval vein/right atrial junction was confirmed at angiography and dilated with resolution of all remaining oedema and fluid collections. Repeat venography at 9 months of age showed a normal superior caval vein and she remains well at 15 months.

Comparison of five clinical weaning indices

BACKGROUND: Despite extensive data acquired in the area of weaning, clinicians still struggle with the questions of how and when to begin the process. Clinical weaning indices, designed to predict weaning potential, are often difficult to use. They provide an answer at a specific time; extrapolation to the weaning process is rarely possible. No single index has proven to be superior. OBJECTIVES: To test the efficacy of five clinical weaning indices (Burns Weaning Assessment Program; Weaning Index; frequency tidal volume ratio; compliance, resistance, oxygenation and pressure index; and negative inspiratory pressure) at regular intervals during withdrawal of ventilatory support and to determine threshold levels for the program. METHODS: A prospective convenience sample consisted of 37 adult critical care patients requiring mechanical ventilation for at least 7 days and identified as stable and ready to wean. Data were collected on all weaning indices every other day until the patient was weaned. RESULTS: With the exception of the Burns Weaning Assessment Program, weaning indices did not change significantly from preweaning scores. Furthermore, the results failed to demonstrate that any of the five clinical weaning indices have strong predictive power related to weaning trial outcomes, although all the indices had negative predictive values that may be helpful in predicting unsuccessful weaning trials. CONCLUSIONS: The results of this study suggest that the process of weaning may be enhanced by comprehensive, systematic approaches and that clinical weaning indices like the Burns Weaning Assessment Program might best serve as tools to track trends in progress, keep care planning on target, and prevent unsuccessful weaning trials.

Maintenance of identical p53 mutations throughout progression of squamous cell carcinomas of the tongue

The occurrence of mutations within the coding sequence of the p53 tumour suppressor gene is now well documented for squamous cell carcinomas of the head and neck region. However, evidence that these mutations are required for the maintenance and progression of squamous tumours is still formally lacking. To test this we have examined whether p53 mutations detected in primary squamous cell carcinomas of the tongue are also detected in the corresponding lymph node metastases. Three different p53 mutations were detected in each of three primary tongue squamous cell carcinomas (SCC), and in each case the same mutation was detected in a lymph node metastasis excised from the same patient. Although the sample number is small, the chance of obtaining the same p53 mutation independently in both the primary and metastatic tumour of each patient is at least 10(-4), therefore the results indicate that keratinocytes harbouring these p53 mutations possess a selective advantage throughout SCC progression.