Pediatric endotracheal tube selection: a comparison of age-based and height-based criteria

Many methods are taught and used clinically to determine what size uncuffed endotracheal tube is required for the pediatric patient. The purpose of this study was to compare the effectiveness of two methods of selection used clinically: (1) the traditional age-based (AB) formula; (age in years +16) divided by 4, and (2) the method based on body length using the Broselow pediatric resuscitation tape. Following institutional review board approval, 174 patients were prospectively studied after informed consent was obtained. Uncuffed endotracheal tube size selection was determined by randomly assigning the patient to one of the two groups. The appropriateness of the tube selection was assessed using an audible air leak around the endotracheal tube. No difference was found between the AB group and the resuscitation tape group with respect to selecting the appropriate size of endotracheal tube. Retrospective analysis of all patients found another AB formula that is occasionally used ([age in years +18] divided by 4) to be correct in only 20 (11%) of 174 cases. This was significantly different from the other methods (P < .001). Since the AB formula ([age in years +16] divided by 4) is reliable and easily applied, it appears acceptable for routine anesthesia cases in the pediatric population requiring endotracheal intubation. The AB formula ([age in years +18] divided by 4) should be used cautiously because of the high failure rate. In circumstances in which general information, such as age, is not available and endotracheal intubation is needed, the Broselow tape allows reliable endotracheal tube size identification and should be readily available.

The role of type-1 and type-2 T-helper immune responses in HIV-1 vaccine protection

The dichotomy of type-1 and type-2 T-helper (Th) immune responses is thought to be an obstacle to develop Human immunodeficiency virus-type- (HIV-1) vaccines capable of inducing effective cellular as well as humoral immune responses. Macaca mulatta were immunized using two different HIV-1sf2 envelope vaccine strategies, based on either immune-stimulating complexes (ISCOM) or chimeric Fowlpox (FP) vaccines. One month following the third immunization all animals were heterologously challenged with simian/human immunodeficiency virus (SHIVsf13). Vaccinated monkeys, which were protected had the highest levels of both type-1 and type-2 HIV-1 specific T-helper cell (Th) responses in addition to the highest homologous and heterogenous virus neutralizing antibodies. To determine how long Th responses persisted and if they correlated with protection, animals were rechallenged after waiting for four months without re-boosting. Macaques which maintained the highest gp120-specific type-1 (IFN-gamma) responses were protected, while there was evidence of viral clearance in two others. These findings demonstrate the importance of both or mixed type-1 and type-2 Th responses in HIV-1 vaccine induced immunity while suggesting a possible role of persistent type-1 responses in maintaining protective immunity over time.

Combination therapy with thymosin alpha1 and interferon for the treatment of chronic hepatitis C infection: a randomized, placebo-controlled double-blind trial

Hepatitis C is a major cause of liver disease leading to cirrhosis. Although interferon (IFN) is the only approved therapy, treatment is characterized by low response rates and dose-limiting side effects. We evaluated the addition of thymosin alpha1 (TA1), an immunomodulatory peptide, to the standard treatment regimen for hepatitis C to determine if combination therapy shows biological activity using outcome measures including normalization of alanine aminotransferase levels, histological activity, and viral load during treatment. We performed a randomized, double-blind, placebo-controlled trial to compare the biological activity of a combination TA1 and IFN with that seen for IFN alone in patients with chronic hepatitis C infection. One hundred nine patients were randomized for intention to treat and received 1.6 mg of TA1 subcutaneously twice weekly and 3 MU of IFN three times weekly; 3 MU of IFN three times weekly and placebo TA1; or placebo for both agents. All patients had chronic HCV infection with confirmation of chronic hepatitis on liver biopsy. Biochemical responders were followed up until alanine aminotransferase (ALT) levels became abnormal or for 26 weeks, and relapsers were retreated for 26 weeks in the same treatment arm. One hundred three patients completed treatment for 26 weeks, and six patients dropped out. The groups were similar with regard to sex, gender distribution, baseline histological activity index (HAI) score, risk factors, and viral titers. End-of-treatment biochemical response was seen in 37.1% of patients treated with combination therapy, 16.2% of patients treated with IFN alone, and 2.7% of untreated controls by intent-to-treat analysis (IFN/TA1 vs. IFN, chi2 = 4.05, P = .04). HCV RNA clearance was seen in 37.1% of IFN/TA1-treated patients and 18.9% of IFN-treated subjects. Mean HCV RNA titers were significantly lower than baseline at weeks 8, 16, and 24 after drug initiation among patients treated with IFN/TA1 but not in the other treatment arms. Histological improvement, as evidenced by a decrease in HAI of more than two points, occurred in the combination therapy arm more frequently than in comparison groups. Cumulative sustained biochemical responses were 14.2% and 8.1% in the IFN/TA1 and IFN arms, respectively, based on an intention-to-treat model. The combination of TA1 and standard IFN treatment for chronic hepatitis C showed evidence of biological activity at the completion of treatment by biochemical, histological, and virological outcome measures. Further research involving longer duration and varied dosing is needed.

Half corneal light shield as a delivery system for standardized application of mitomycin C

PURPOSE

The authors develop a simple and economical method of applying reproducible intraoperative doses of mitomycin C for glaucoma filtering surgery.

METHODS

A three-part protocol was developed to study several properties of half corneal light shields (HCLSs). Part A tested the amount of mitomycin C (0.4 mg/ml) absorbed, the expansion dimensions attained, and the amount released to filter paper. In part B, the in vitro release of mitomycin C to an enucleated pig eye was examined. In part C, the in vivo release during intraoperative filtering surgery was tested.

RESULTS

The amount of mitomycin C solution absorbed by the HCLSs ranged from 1.07 x 10(-2) mg to 1.19 x 10(-2) mg; expansion width ranged from 6.8 mm to 7.0 mm; expansion height ranged from 3.6 mm to 3.8 mm; expansion thickness was constant at 0.6 mm. The amount of solution released to filter paper ranged from 6.8 x 10(-3) mg to 8.6 x 10(-3) mg. The amount of solution transferred to the pig eye ranged from 1.0 x 10(-3) mg to 2.7 x 10(-3) mg. The amount of solution released in filtering surgery ranged from 2.0 x 10(-3) mg to 4.8 x 10(-3) mg.

CONCLUSIONS

The contact surface area, the amount absorbed, and the amount released by each HCLS was reproducible. The uniform thickness theoretically provides a uniform distribution of mitomycin C. This method may allow standardization of intraoperative mitomycin C application, and may reduce the incidence of complications.

Role of the estrogen receptor in the action of organochlorine pesticides on estrogen metabolism in human breast cancer cell lines

As interest in the properties of xenoestrogenic compounds has grown, different in vitro cell culture systems have been proposed as models, against which to gauge relative estrogenic impact. Previous research indicated that some organochlorine-based pesticides elevated the production of 16 alpha-hydroxyestrone relative to 2-hydroxyestrone in ER+ MCF-7 breast cancer cells while phytochemicals like indole-3-carbinol reduced this ratio. That this ratio may be a biological marker of the risk of breast cancer has recently been demonstrated. In this study we have carried out the same paradigm in two ER- cell lines to examine the effect of receptor status. To determine whether the impact of chlorinated pesticides can be modulated by phytochemicals, the ability of indole-3-carbinol or brassinin to reverse the changes in metabolism was examined. Non-persisting phosphorus-based pesticides were also studied and shown not to have an effect on estrogen metabolism. The implications of these findings are examined.

Determination of cerebral glucose transport and metabolic kinetics by dynamic MR spectroscopy

A new in vivo nuclear magnetic resonance (NMR) spectroscopy method is introduced that dynamically measures cerebral utilization of magnetically labeled [1-13C]glucose from the change in total brain glucose signals on infusion. Kinetic equations are derived using a four-compartment model incorporating glucose transport and phosphorylation. Brain extract data show that the glucose 6-phosphate concentration is negligible relative to glucose, simplifying the kinetics to three compartments and allowing direct determination of the glucose-utilization half-life time [t1/2 = ln2/(k2 + k3)] from the time dependence of the NMR signal. Results on isofluorane (n = 5)- and halothane (n = 7)-anesthetized cats give a hyperglycemic t1/2 = 5.10 +/- 0.11 min-1 (SE). Using Michaelis-Menten kinetics and an assumed half-saturation constant Kt = 5 +/- 1 mM, we determined a maximal transport rate Tmax = 0.83 +/- 0.19 mumol.g-1.min-1, a cerebral metabolic rate of glucose CMRGlc = 0.22 +/- 0.03 mumol.g-1.min-1, and a normoglycemic cerebral influx rate CIRGlc = 0.37 +/- 0.05 mumol.g-1.min-1. Possible extension of this approach to positron emission tomography and proton NMR is discussed.

Has your organization leveraged the benefits of a computerized patient record?

Health care organizations have responded to the shift to capitated payments by reengineering and streamlining their operations. Most are planning for the automation of health care delivery through the Implementation of clinical information systems. The cornerstone of these systems is the computerized patient record (CPR), which it is believed will increase productivity, cut costs, and provide improved clinical outcomes information. The promise of the CPR is instantaneous access to a patient's information when needed, with historical and current clinical information, from any location. However, not all organizations have realized the value the CPR can provide to manage the demand for health services that ultimately will be necessary for their success. As health systems have identified benefits of an automated patient record, not all are related directly to cost containment; many have either a direct correlation to cost-savings or a risk avoidance that would have been costly to the organization if the alerts, warnings, or access to complete information had not been available. The proactive nature of these tools embedded in the CPR can be one of the greatest long-term benefits to the case manager.

A recombinant prime, peptide boost vaccination strategy can focus the immune response on to more than one epitope even though these may not be immunodominant in the complex immunogen

Rhesus monkeys were successfully vaccinated using a strategy of priming with a candidate envelope subunit vaccine and boosting with synthetic peptides. Priming was carried out with recombinant HIV-1 SF2 envelope glycoprotein incorporated into ISCOMs, following the attachment of a lipid tail. Peptides, covalently linked to ISCOMs, representing linear sequences with the V2 and V3 regions, were used to boost functional antibodies-to neutralizing epitopes in both of these regions. Injections with these peptide formulations substantially increased the titre of serum neutralizing antibodies from low or undetectable levels. In addition to completely neutralizing the homologous HIV-1 SF2 strain, these sera also neutralized the escape variant, HIV-1 SF13. However, no antibodies were boosted which could compete with human, neutralizing monoclonal antibodies recognising conformational epitopes. The peptides also boosted antibodies to a peptide whose sequence lies close to the V2 region neutralizing epitope but does not overlap with it. Importantly, the level of antibodies to an unrelated epitope associated with enhancement of HIV-1 SF13 continued to fall after the peptide boost. Successful protection against challenge with chimeric simian immunodeficiency virus expressing HIV-1 SF13 envelope glycoproteins (SHIV SF13) may be due to an increase in the ratio of neutralizing to enhancing antibodies by selectively boosting with peptides to critical neutralizing epitopes.

Methodology and feasibility of a home-based examination in disabled older women: the Women's Health and Aging Study

BACKGROUND

To ascertain disease and functional capacity in community-resident disabled older women in the Women's Health and Aging Study (WHAS), a prospective investigation of the causes and course of disability, a home-based standardized physical examination and performance test battery were developed. Thirty-nine tests were administered, 9 by a lay interviewer and 30 by a nurse. This scope and intensity of testing had not been performed previously in a home environment or on such a functionally limited population. Thus, substantial developmental work was required. This report describes the administrative procedures and field experience for each exam component, highlighting innovations pertinent to home administration.

METHODS

Exclusion criteria, safety issues, administration time, completion rates, and reasons for incomplete data are reported. Administration time is based on 30 exams conducted over a 3-week period 90% of the way through baseline data collection. Completion status was determined using all 1,002 participants and is categorized as follows: complete; partial; not done, health; not done, other; and refused.

RESULTS

Seventy-two percent of the screened, eligible respondents completed the 30-min interviewer-administered physical assessment and the 2-hr, 10-min nurse examination. Classifiable data were obtained for 90% of participants on 36 examination items. Lower completion rates were obtained on the other three tests primarily due to exclusions for health-related conditions; environmental constraints and participant refusal were minimal.

CONCLUSION

Extensive, research-oriented physical evaluation can be successfully and safely performed in a home setting. In future studies, home-based examination may be preferable, as participation in the WHAS examination substantially exceeded rates for clinic-based exams in similar populations.

Anaemia of chronic disease in rheumatoid arthritis: in vivo effects of tumour necrosis factor alpha blockade

Anaemia of chronic disease (ACD) is a common feature of active rheumatoid arthritis (RA). Inflammatory cytokines, particularly tumour necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6), are thought to contribute to the pathogenesis of ACD, possibly by inhibiting erythropoietin (EPO) production. In this study, we examined the in vivo effects of TNF-alpha blockade with a chimeric monoclonal antibody, cA2, on erythropoiesis in RA patients with ACD. Administration of cA2 led to a dose-dependent increase in haemoglobin levels compared to placebo and these changes were accompanied by a reduction in both EPO and IL-6 levels. The data support the notion that TNF-alpha is important in the causation of ACD, but suggest a mechanism independent of EPO suppression. Instead, TNF-alpha may act directly on bone marrow red cell precursors.

Munchausen syndrome presenting as trauma

Rarely, a patient with Munchausen syndrome will present with apparent trauma. A computerized literature search from 1966 until the present discovered only three such case reports, none of which appeared in a surgical journal. We report a fourth case. The characteristics of Munchausen syndrome are illustrated. The possibility that such a patient may have a true injury is also discussed.

Intracellular volume and apparent diffusion constants of perfused cancer cell cultures, as measured by NMR

Diffusion NMR spectroscopy was used to study intracellular volume and apparent water diffusion constants in different cell lines (DU145, human prostate cancer; AT3, rat prostate cancer; MCF-7, human breast cancer; RIF-1, mouse fibrosacroma). The cells were grown on various matrices (collagen sponge, collagen beads, polystyrene beads) which enabled continuous growth in perfused high density cell culture suitable for NMR studies. In perfused cell systems, the attenuation of the water signal versus the squared gradient strength was fitted by the sum of two decaying exponentials. For the slowly decaying component the apparent water diffusion constant at 37 degrees C was 0.22 (+/-0.02) x 10(-9) s/m2 for all cell lines at diffusion times > 100 ms. It continuously increased up to 0.47 (+/-0.05) x 10(-9) s/m2 when the diffusion time was decreased to 8 ms, indicating restricted diffusion. No significant effect of the matrices was observed. The fractional volume of the slow component as determined from the biexponential diffusion curve correlated with the relative intracellular volume, as obtained from the cell density in the sample and the cell size as measured by light microscopy. Therefore, this simple NMR approach can be used to determine intracellular volume in perfused cell cultures suitable for NMR studies. Using this information in combination with spectroscopic data, changes in intracellular metabolite concentration can be detected even when the cellular volume is changing during the experiment. The apparent diffusion constant for the fast diffusing component varied with growth matrix, cell density and cell type and also showed the typical characteristics of restricted diffusion (increase of apparent diffusion constant with time).

Magnetic resonance imaging of children without sedation: preparation with simulation

OBJECTIVE

It was hypothesized that a scanner simulator that replicates the magnetic resonance imaging (MRI) environment could be used to prepare pediatric subjects for successful completion of a diagnostic-quality MRI examination without pharmacological sedation.

METHOD

Sixteen healthy children, 6 to 17 years of age, were matched for age and sex with 16 psychotropic medication-naive children with obsessive-compulsive disorder. Distress was measured throughout simulation and scanning procedures using heart rate and a self-report distress scale. Ten healthy children, 6 to 17 years of age, also underwent the same actual MRI scanning procedure but did not undergo the simulation scanning procedure.

RESULTS

Significant decreases in heart rate and self-reported distress level were observed in all subjects during the simulator session that were maintained to the end of the actual scanner experience. All subjects successfully completed MRI examinations without chemical restraint. Subjects who were not trained in the simulator had higher heart rates and self-reported distress levels in the actual scanner than did simulation-trained subjects.

CONCLUSIONS

Simulation without pharmacological sedation successfully prepared pediatric subjects in this pilot study for high-quality MRI studies. Subject preparation may be an alternative procedure to sedation for routine MRI examination in healthy and anxious children 6 years of age and older.

Effects of an immune-enhancing diet in critically injured patients

OBJECTIVE

To determine the effects of an immune-enhancing experimental diet (XD = supplemental arginine, trace elements, and increased omega-3 fatty acids) versus standard diet (SD), on immune cell function and clinical outcome of critically injured patients.

DESIGN

Prospective randomized clinical trial of patients admitted to the surgical intensive care unit after trauma (Injury Severity Score > 13).

MATERIALS AND METHODS

Patients received early enteral nutrition with either XD or SD for a minimum of 5 days.

MEASUREMENTS

Mortality, intensive care unit, ventilator, and hospital days, as well as incidence of adult respiratory distress syndrome (ARDS) and infectious complications were recorded. Nutritional parameters were also studied. Peripheral blood leukocytes were isolated from normal volunteers and from patients on days 1, 6, and 10 of feeding.

MAIN RESULTS

Demographics and injury severity were similar in both groups. Both SD (n = 21) and XD (n = 22) groups revealed depressed monocyte function (tumor necrosis factor, prostaglandin E2, and procoagulant activity) on day 1 compared with a reference group (p < 0.05). However, monocytes from XD patients began to "normalize" their response (tumor necrosis factor, prostaglandin E2, and procoagulant activity) by day 6. Although ARDS occurred more frequently in the XD group (45 vs. 19%), the majority of ARDS in both groups occurred very early, with only three patients in the XD (13.6%) and one patient in the SD (4.7%) groups developing ARDS after study entry. XD patients remained on the ventilator longer (16.4 vs. 9.7 days) and in the hospital longer (32.9 vs. 22 days) compared with the SD group, but overall mortality was nearly identical (4.5 vs. 5%).

CONCLUSION

The exact role and timing for diets with immune-enhancing effects has yet to be defined.

Intraoperative microvascular Doppler sonography in aneurysm surgery

OBJECTIVE

The goal was to evaluate the efficacy and reliability of intraoperative microvascular doppler sonography for the assessment of cerebral hemodynamics in aneurysm surgery.

METHODS

For 35 patients who underwent surgery for the treatment of 42 intracranial aneurysms, microvascular doppler sonography with a 20-MHz probe (1-mm diameter) was used before and after clip application, to confirm the obliteration of aneurysms. Assessment of the patency of the parent vessels and all branching arteries was performed. The findings from doppler sonography were confirmed with either intraoperative angiography or immediate postoperative angiography.

RESULTS

The 1-mm microprobe was able to insonate all vessels of the circle of Willis and their major branches; furthermore, perforating arteries were reliably insonated. For 11 patients (31%), doppler sonography exposed parent artery or branching artery stenosis or occlusion and guided the immediate adjustment of aneurysm clip placement. The findings from intraoperative microvascular doppler sonography correlated with findings from angiography in all cases. There were no complications of microvascular doppler probe use.

CONCLUSION

Intraoperative microvascular doppler sonography is a safe, instantaneous, effective, reliable, and cost-effective method for documenting the patency of parent vessels, arterial branches, and major perforators and the complete occlusion of cerebral aneurysms. This technique can be reliably used, in many instances, instead of intraoperative angiography for the surgical treatment of aneurysms.

Major depression and all-cause mortality among white adults in the United States

PURPOSE

Depression is the most common psychiatric illness affecting adults. Despite the importance of a potential link between major depression and mortality, research has been surprisingly sparse.

METHODS

Information on 57,897 white adults aged 25 years and older who were included in the mental health supplement of the 1989 National Health Interview Survey was linked with the National Death Index to examine the relationship of major depression to mortality. Death status was obtained through December 1991. Sex-specific hazard rate ratios for mortality were calculated by Cox proportional hazards regression and Poisson regression to adjust for potential confounders (age, education, marital status, body mass index, and whether the target subject or a family member completed the survey about the subject).

RESULTS

Major depression was reported for 223 (0.8%) of 27,345 men and 392 (1.3%) of 30,552 women. During the 2.5-year follow-up, death certificate data were obtained for 848 (3.1%) men and 651 (2.1%) women. The adjusted hazard rate ratios for all-cause mortality associated with major depression were 3.1 (95% confidence interval; 2.0-4.9) for men and 1.7 (95% confidence interval; 0.9-3.1) for women.

CONCLUSIONS

These results suggest that major depression increases risk of all-cause mortality, particularly among men. Further research is needed to explain the mechanism.

The human homologue of yeast CRM1 is in a dynamic subcomplex with CAN/Nup214 and a novel nuclear pore component Nup88

The oncogenic nucleoporin CAN/Nup214 is essential in vertebrate cells. Its depletion results in defective nuclear protein import, inhibition of messenger RNA export and cell cycle arrest. We recently found that CAN associates with proteins of 88 and 112 kDa, which we have now cloned and characterized. The 88 kDa protein is a novel nuclear pore complex (NPC) component, which we have named Nup88. Depletion of CAN from the NPC results in concomitant loss of Nup88, indicating that the localization of Nup88 to the NPC is dependent on CAN binding. The 112 kDa protein is the human homologue of yeast CRM1, a protein known to be required for maintenance of correct chromosome structure. This human CRM1 (hCRM1) localized to the NPC as well as to the nucleoplasm. Nuclear overexpression of the FG-repeat region of CAN, containing its hCRM1-interaction domain, resulted in depletion of hCRM1 from the NPC. In CAN-/- mouse embryos lacking CAN, hCRM1 remained in the nuclear envelope, suggesting that this protein can also bind to other repeat-containing nucleoporins. Lastly, hCRM1 shares a domain of significant homology with importin-beta, a cytoplasmic transport factor that interacts with nucleoporin repeat regions. We propose that hCRM1 is a soluble nuclear transport factor that interacts with the NPC.

Human keratinocytes maintain reversible anti-apoptotic defenses in vivo and in vitro

Human keratinocytes proliferate and differentiate in an epidermal environment where induction of apoptosis can be triggered by ultraviolet radiation (UVR), activated lymphocytes and cytokines. The purpose of this study was to determine whether keratinocytes were susceptible to apoptosis induced by ionophore, ultra-violet radiation, cytokines or crosslinking of CD95 (Fas/APO-1). In normal human skin exposed to two minimal erythema doses of ultraviolet radiation, suprabasal cells were the first keratinocytes to demonstrate apoptotic nuclei, and by 48 h apoptotic cells were identified throughout the mid to upper epidermis. However, most keratinocytes resisted apoptosis and UVR-induced apoptosis was not observed in basal cells, or in the most differentiated epidermis. Human keratinocytes and keratinocyte cell lines cultured in vitro developed maximal apoptosis 48 h after radiation. Human keratinocytes cultured in full growth factor supplements were resistant to UVR-induced apoptosis compared to keratinocyte cell lines or to a lymphoid cell line (HL60) susceptible to apoptosis. Keratinocyte cell lines were completely resistant to apoptosis induced by interferon-gamma, interferon-alpha, IL-2, IL-6, TNF-alpha, IL-1Ra, and GM-CSF. A subset of the cells in cultures of keratinocytes and transformed keratinocyte cell lines died by apoptosis in response to anti-Fas, IL-1alpha and TNF-alpha plus IFN-gamma and ionophore. Second passage freshly isolated human keratinocytes were much more resistant to apoptosis induced by ionophore, anti-Fas and cytokines than were transformed keratinocyte cell lines. Calcium shift to induce differentiation in second-passage keratinocyte cultures made keratinocytes even more resistant to UVR-induced apoptosis. This parallels the lack of UVR-induced apoptosis observed in the most differentiated keratinocytes in irradiated human skin. Both keratinocytes and keratinocyte cell lines express rather low levels of the anti-apoptotic proteins bcl-2 and bcl-x compared to other apoptosis-resistant cell types. The differences between keratinocytes and keratinocyte cell lines in susceptibility to apoptosis are not explained by difference in expression of bcl-2 or bcl-x. Finally, withdrawal of growth factors from keratinocytes decreased cell survival following UVR and increased the induction of apoptosis. Inhibition of protein synthesis with cyclo-heximide also made keratinocytes more susceptible to UVR-induced apoptosis, indicating that anti-apoptotic defences in cultured keratinocytes are dependent on active protein synthesis. These experiments show that the strong keratinocyte defences against apoptosis are stratified within the epidermis, and can be altered by differentiation and growth factor withdrawal.