Health care for the school-age child

The research related to health care for school-age children is reviewed. Two major categories are considered, namely, health-risk behavior and psychosocial health. Research related to the emerging issues of homelessness and AIDS is also reviewed. The research completed to date on school-age children's health care is critiqued with an emphasis on the state of the science in nursing. Recommendations for further research are provided.

Antiproliferative mechanism of action of cryptophycin-52: kinetic stabilization of microtubule dynamics by high-affinity binding to microtubule ends

Cryptophycin-52 (LY355703) is a new synthetic member of the cryptophycin family of antimitotic antitumor agents that is currently undergoing clinical evaluation. At high concentrations (>/=10 times the IC50), cryptophycin-52 blocked HeLa cell proliferation at mitosis by depolymerizing spindle microtubules and disrupting chromosome organization. However, low concentrations of cryptophycin-52 inhibited cell proliferation at mitosis (IC50 = 11 pM) without significantly altering spindle microtubule mass or organization. Cryptophycin-52 appears to be the most potent suppressor of microtubule dynamics found thus far. It suppressed the dynamic instability behavior of individual microtubules in vitro (IC50 = 20 nM), reducing the rate and extent of shortening and growing without significantly reducing polymer mass or mean microtubule length. Using [3H]cryptophycin-52, we found that the compound bound to microtubule ends in vitro with high affinity (Kd, 47 nM, maximum of approximately 19.5 cryptophycin-52 molecules per microtubule). By analyzing the effects of cryptophycin-52 on dynamics in relation to its binding to microtubules, we determined that approximately 5-6 molecules of cryptophycin-52 bound to a microtubule were sufficient to decrease dynamicity by 50%. Cryptophycin-52 became concentrated in cells 730-fold, and the resulting intracellular cryptophycin-52 concentration was similar to that required to stabilize microtubule dynamics in vitro. The data suggest that cryptophycin-52 potently perturbs kinetic events at microtubule ends that are required for microtubule function during mitosis and that it acts by forming a reversible cryptophycin-52-tubulin stabilizing cap at microtubule ends.

Differential regulation of the interleukin-12 receptor during the innate immune response to Leishmania major

Previous studies have shown the central role of interleukin 12 (IL-12) in the development of resistance to Leishmania major infection in C3H mice. We now show that during the innate immune response the lymph node cells of L. major-infected C3H mice upregulate the IL-12 receptor on CD4(+), CD8(+), and B220(+) cells. An increase in the ability of the lymph node cells to bind IL-12 correlates with 9.3- and 4.6-fold increases in the mRNA expression levels of the IL-12Rbeta1 and -beta2 subunits, respectively. In contrast, BALB/c mice, which are susceptible to L. major infection, have no increase in the ability of the lymph node cells to bind IL-12 and correspondingly smaller increases in the mRNA expression levels of the IL-12Rbeta1 and -beta2 subunits of 2- and 1.5-fold, respectively. Neutralizing IL-4 and the administration of exogenous IL-12 upregulate IL-12R expression in BALB/c mice, while the neutralization of IL-12 in C3H mice blocks increased IL-12 receptor expression. These experiments reveal an important role for the regulation of the IL-12 receptor during the innate immune response after infection of mice with a pathogen.

Collagen: ubiquitous in nature, multifunctional in devices

Collagen is a protein that is widely distributed in humans and plays an important role in many aspects of tissue performance. This versatility is central to the uses of collagen in biomedical devices. The structure and properties of collagen and the basis for their biomedical uses are described in this article.

Hospital-wide restriction of clindamycin: effect on the incidence of Clostridium difficile-associated diarrhea and cost

BACKGROUND

Widespread antibiotic use has been associated with increases in both bacterial resistance and nosocomial infection.

OBJECTIVE

To characterize the impact of hospital-wide clindamycin restriction on the incidence of Clostridium difficile-associated diarrhea and on antimicrobial prescribing practices.

DESIGN

Prospective, observational cohort study.

SETTING

University-affiliated Veterans Affairs Medical Center.

PATIENTS

Hospitalized patients with symptomatic diarrhea.

MEASUREMENTS

Clinical data on individual patients and data on antibiotic use were obtained from hospital pharmacy records. Hospital-wide use of antimicrobial agents was monitored. Isolates of C. difficile underwent antimicrobial susceptibility testing and molecular typing.

RESULTS

An outbreak of C. difficile-associated diarrhea was caused by a clonal isolate of clindamycin-resistant C. difficile and was associated with increased use of clindamycin. Hospital-wide requirement of approval by an infectious disease consultant of clindamycin use led to an overall reduction in clindamycin use, a sustained reduction in the mean number of cases of C. difficile-associated diarrhea (11.5 cases/month compared with 3.33 cases/month; P < 0.001), and an increase in clindamycin susceptibility among C. difficile isolates (9% compared with 61%; P < 0.001). A parallel increase was noted in the use of and costs associated with other antibiotics with antianaerobic activity, including cefotetan, ticarcillin-clavulanate, and imipenem-cilastin. The hospital realized overall cost savings as a result of the decreased incidence of C. difficile-associated diarrhea.

CONCLUSIONS

Hospital formulary restriction of clindamycin is an effective way to decrease the number of infections due to C. difficile. It can also lead to a return in clindamycin susceptibility among isolates and can effect cost savings to the hospital.

Safety of trovafloxacin in treatment of lower respiratory tract infections

Safety and toleration of oral trovafloxacin has been assessed in Phase III trials in patients with acute lower respiratory tract infections. Patients were treated orally with either trovafloxacin 100 or 200 mg (n=881) or a comparator (500 or 1000 mg amoxicillin, or 625 mg amoxicillin/clavulanic acid; n = 593). Adverse events were recorded in 112 (12.7%) trovafloxacin- and 74 (12.5%) comparator-treated patients. Frequency of effects on the autonomic nervous, musculoskeletal, respiratory, special senses, urinary and reproductive systems was <1%. Photosensitivity reactions were not reported in trovafloxacin-treated patients. Central or peripheral nervous system adverse effects (headache and dizziness) were slightly more common in trovafloxacin-treated patients (4.4% vs 1.9%). Patients treated with comparators experienced gastrointestinal events more frequently (6.1% vs 8.3%). Comparable incidences of adverse events were reported in patients > or = 65-years-old. Most events were mild to moderate in severity. Treatment was discontinued because of an adverse event in 18 (2%) trovafloxacin- and four (0.7%) comparator-treated patients. Despite the high prevalence of risk factors, serious adverse events were rare and the mortality rate over the 35-day study period was low: trovafloxacin 0.8%, comparator agents 1.5%. Laboratory test abnormalities were recorded in less than 1% of patients in either treatment group.

The impact of psychosocial need and needs resolution on quality of life in patients with brain tumors

The diagnosis of cancer of the central nervous system (CNS) is often the diagnosis of an incurable, progressive disease with devastating effects on the physical, psychosocial, and cognitive functioning of patients. Because many of the treatment options are noncurative in nature, issues related to quality and quantity of life become paramount.

The purpose of the authors' research was to explore the prevalence of psychosocial needs in this cancer population and to determine whether these needs and their resolution impact on quality of life (QOL).

Telephone interviews were conducted with 75 patients in whom primary CNS cancer was diagnosed and who were able to pass the Mini-Mental Health Status Examination. Analysis of results indicated that the majority of patients (97.3%) had at least one concern; concerns over treatment side effects, controlling uncertainty, having a meaningful existence, self and body image, and family concerns were among the five most frequently cited need domains. Most patients (91.8%) received help. However, 75.3% reported needing additional help. The number of needs reported and the severity of fatigue most significantly impacted QOL.

The study identified the needs and experiences of the patient with CNS cancer. Quality of life and needs assessment information can be used to screen patients for distress and to measure the outcome of medical and psychosocial care and ultimately to ease the burden of illness.

PET scanning in head and neck oncology: a review

BACKGROUND

The objective of this study was to review and describe the usage of fluorine-labeled deoxyglucose (FDG) and positron emission tomography (PET) in the diagnosis and management of head and neck cancer.

METHODS

Several prospective series,-including 159 newly diagnosed and previously untreated and 23 previously irradiated head and neck squamous cell carcinoma patients initially seen at the Wake Forest University Medical Center and evaluated by clinical examination, conventional computed tomography/ magnetic resonance imaging (CT/MRI) scans, PET scans, and histopathologic studies,-were reviewed and the findings summarized for comparison of the correct differentiation of primary and metastatic cancers and for postirradiation tumor clearance in a subsegment of those cases.

RESULTS

Positron emission tomography scanning using a fluorine-labeled deoxyglucose (FDG) radiotracer proved as reliable as conventional scanning for primary and metastatic tumor identification. Compared with clinical examination, PET was better for identification of nodal metastatic tumors but poorer for small primary tumors. For previously irradiated patients treated at least 4 months before the test, PET scanning was clearly superior to clinical examination and conventional imaging in differentiating tumor recurrence from soft-tissue irradiation effects.

CONCLUSIONS

Fluorine-labeled deoxyglucose-PET scanning is comparable to conventional imaging of head and neck cancers in detecting primary and metastatic carcinoma. Lack of anatomic detail remains its major drawback. Currently, its greatest role is in the evaluation of the postradiotherapy patient.

From leaking devices to smart permeability: the technology of diffusion and other transport mechanisms

Some devices are required to be totally leak-proof, others are specifically designed to control permeability of one component through another. Some of the principles of diffusion and some of the practical applications are discussed in this article.

From outer space to inner space. Neuroscience research aboard the space shuttle

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Trial by media: the case of the worn hip prostheses

Another example of a medical device failing to produce a uniformly satisfactory performance is being widely discussed in the media. The controversy it arouses reduces patient confidence in the industry and calls into question the value of some technical developments and the effectiveness of regulatory procedures. Some of the generic issues arising from this case are discussed in this article.

Immunogenicity of two efficacious outer membrane protein-based serogroup B meningococcal vaccines among young adults in Iceland

Serum bactericidal activity (SBA) and ELISA antibody levels elicited by two efficacious serogroup B meningococcal vaccines were measured in a controlled trial involving 408 15- to 20-year-olds. Subjects were given two doses at a 6-week interval of a serogroup B or control vaccine. Response was defined as > or = 4-fold rise in antibody level. After two doses of the Finlay Institute (Havana) vaccine at 12 months, the proportions of SBA and ELISA responders were not different from those of the control group (15% and 17% [vaccine] vs. 13% and 9% [control], P > .05). After two doses of the National Institute of Public Health (Oslo) vaccine, there were more SBA and ELISA responders than in the control group (47% and 34% [vaccine] vs. 10% and 1% [control]) or the Finlay Institute vaccine group (P < .05 for both). SBA and ELISA may be insensitive correlates for protective efficacy for some outer membrane protein-based serogroup B meningococcal vaccines.

Mental disorder and violence. A special (high security) hospital study

BACKGROUND

From a first clinical description of a complete resident sample of special (high security) hospital patients, we examined the association between mental disorder and violence.

METHOD

A record survey of all 1740 patients resident at any time between 1 January and 30 June 1993, inclusive, and, for most, the official criminal record.

RESULTS

1015 patients (58%) had functional psychosis, one-quarter of whom also had an independent personality disorder; 461 (26%) had personality disorders uncomplicated by psychosis, and 264 (16%) had learning disabilities. Pre-admission substance misuse, which was probably under-recorded, had been most common among those with psychosis and an independent personality disorder. Less than 10% had never been convicted of a criminal offence, although 25% had been admitted directly from other hospitals. Direct personal violence was more common among men, and fire-setting among women. Schizophrenia was most strongly associated with personal violence. More than 75% of those with a psychosis were recorded as being driven to offend by their delusions. In the absence of delusions, hallucinations had no such effect.

CONCLUSIONS

For people with personality disorder better clinical descriptions seem essential. For people with a pure psychosis, as symptoms were usually a factor driving the index offence, treatment appears as important for public safety as for personal health.

The right time and the right place: the concepts and concerns of drug delivery systems

The distinction between active drugs and active biomaterials is being gradually eroded. One of the areas where the interface between drugs and devices needs greater clarity is controlled delivery of drugs by materials and this article discusses the basic mechanisms that are involved.

Mitochondrial redox state as a potential detector of liver dysoxia in vivo

Dysoxia can be defined as ATP flux decreasing in proportion to O2 availability with preserved ATP demand. Hepatic venous beta-hydroxybutyrate-to-acetoacetate ratio (beta-OHB/AcAc) estimates liver mitochondrial NADH/NAD and may detect the onset of dysoxia. During partial dysoxia (as opposed to anoxia), however, flow may be adequate in some liver regions, diluting effluent from dysoxic regions, thereby rendering venous beta-OHB/AcAc unreliable. To address this concern, we estimated tissue ATP while gradually reducing liver blood flow of swine to zero in a nuclear magnetic resonance spectrometer. ATP flux decreasing with O2 availability was taken as O2 uptake (VO2) decreasing in proportion to O2 delivery (QO2); and preserved ATP demand was taken as increasing Pi/ATP. VO2, tissue Pi/ATP, and venous beta-OHB/AcAc were plotted against QO2 to identify critical inflection points. Tissue dysoxia required mean QO2 for the group to be critical for both VO2 and for Pi/ATP. Critical QO2 values for VO2 and Pi/ATP of 4.07 +/- 1.07 and 2.39 +/- 1.18 (SE) ml . 100 g-1 . min-1, respectively, were not statistically significantly different but not clearly the same, suggesting the possibility that dysoxia might have commenced after VO2 began decreasing, i.e., that there could have been "O2 conformity." Critical QO2 for venous beta-OHB/AcAc was 2.44 +/- 0.46 ml . 100 g-1 . min-1 (P = NS), nearly the same as that for Pi/ATP, supporting venous beta-OHB/AcAc as a detector of dysoxia. All issues considered, tissue mitochondrial redox state seems to be an appropriate detector of dysoxia in liver.

The special prenatal clinic: one approach to women and substance abuse

We aimed to determine if the trend in substance use in this central core of a large inner-city area confirmed an increase in marijuana use among young women < 22 years of age as childbearing years were beginning or if marijuana use and harder drug use were greatest among women beyond the teens and the early second decade of life and to describe one prenatal care intervention. Statistical reports for the Special Prenatal Clinic, a Harlem clinic for women with a current or past history of substance use, were reviewed from 1985 (the clinic's inception) through March 1996 to determine the trends, patterns, and types of drug use. Findings chronicled the beginning and rise in crack cocaine use, especially after 1986, confirmed an increase in marijuana use by adolescents since 1992, and suggest that the risk for use of hard drugs increases with age, predominantly in the childbearing years. Intervention by the Special Prenatal Clinic aided case-finding, allowed for comprehensive care, offered women opportunities for behavior change, and increased their chances of keeping their babies after delivery.

The drug treatment of alcohol withdrawal symptoms: a systematic review

A computer-assisted and cross-reference literature search identified trials of therapy for alcohol withdrawal symptoms. Those with a randomized, double-blind placebo-controlled design were systematically assessed for quality of methodology. Fourteen studies were identified investigating 12 different drugs. The quality of methodological design, even among this highly selected group of published studies, was often poor. Study populations were generally under-defined, most studies excluded severely ill patients, control groups were poorly matched, and the use of additional medication may have confounded results in some studies. Twelve different rating scales were used to assess severity of symptoms. All 12 compounds investigated were reported to be superior to placebo, but this has only been replicated for benzodiazepines and chlormethiazole. Further research using better methods is required to allow comparison of different drugs in the treatment of alcohol withdrawal symptoms. On the evidence available, a long-acting benzodiazepine should be the drug of first choice.

Mortality and rebleeding following Transjugular Intrahepatic Portosystemic Stent Shunt for variceal haemorrhage

The present study investigates clinical factors associated with decreased survival following Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS). Sixty-seven patients underwent TIPSS for bleeding related to portal hypertension, 42 (63%) on an urgent basis. TIPSS was successfully placed in 65 (97%) patients with no fatal procedural complications. Thirty day mortality was 21%, there being several predictive factors: transfer from another institution, urgency of procedure, sepsis, encephalopathy, higher mean serum bilirubin and low serum albumin. However, using regression analysis, 30 day mortality was predicted independently only by severe liver disease (Child-Pugh C, P= 0.003) and older age (P= 0.003). When stratified by Child-Pugh class, cumulative survival rates at 1 year for class A, B and C were 100, 90 and 34%, respectively. Only three of 25 patient deaths were due to variceal rebleeding. Thirty (46%) patients had a total of 41 rebleeding episodes, with mean time to first rebleed of 4.8 months (range, 3 days-38 months). Cumulative rebleeding rate at 1 year was 25%. Log-rank analysis did not reveal a significant difference in overall survival between rebleeders and non-rebleeders (P= 0.125). When investigated, shunt abnormalities (stenosis, occlusion) were identified in all cases of rebleeding. Our findings confirm TIPSS can be safe and effective in the control of refractory variceal haemorrhage. However, prognosis remains poor for patients with advanced liver disease, particularly if older and in the emergency setting. Vigilant surveillance and high rate of intervention is necessary to maintain shunt patency. Consideration could be given to elective shunt surgery instead of TIPSS for patients with recurrent bleeding and good prognosis liver disease.

The effects of antivenom and verapamil on the haemodynamic actions of Chironex fleckeri (box jellyfish) venom

The efficacy of antivenom and verapamil against Chironex fleckeri (box jellyfish) venom was investigated in monitored mechanically ventilated piglets. Chironex fleckeri tentacle extract alone, a mixture of tentacle extract with antivenom, and verapamil before tentacle extract were administered intravenously to groups of animals. Tentacle extract caused severe systemic hypotension, cardiac dysrrhythmias, pulmonary hypertension, haemolysis and hyperkalaemia. These effects were prevented by pre-incubation of tentacle extract with antivenom. Verapamil did not prevent any effect of venom, exacerbated cardiovascular collapse and increased mortality. We conclude that antivenom neutralizes the cardiovascular, haemolytic and hyperkalaemic effects of box jellyfish venom. Verapamil does not prevent any of these effects and is contra-indicated for treatment of envenomation.