A holistic approach to network system security

Networks and information systems change continuously, so it is important to create a security process that adapts to change. Here's how to ensure effective network security through a process of assessing, implementing, monitoring, and identifying.

Quality of life and neuropsychological evaluation for patients with malignant astrocytomas: RTOG 91-14. Radiation Therapy Oncology Group

With increasingly aggressive neurosurgical and radiation therapy modalities (gamma knife, external beam stereotactic radiation and interstitial brachytherapy with or without hyperthermia) offered to patients with malignant astrocytomas (MA), increasing national demand for medical outcome studies and rising health care costs amidst public, business, and governmental debate to cut spending, we as physicians are obligated to continue our research to find effective treatments for malignant astrocytoma (MA) and a cost-effective means to study their impact upon the patient's quality of life (QOL).

PURPOSE

We report data that was collected within the Radiation Therapy Oncology Group (RTOG) on 126 patients with MA who were enrolled in RTOG 91-14. This study was undertaken to prospectively test the feasibility of performing quality of life (QOL) and neuropsychological evaluation (NPE) and collecting this data within the RTOG.

RESULTS

The NPE and QOL parameters that were used in this study are cost effective. They are not only much cheaper than formal cognitive and memory testing, but also provide additional information regarding the patients' day to day functional abilities that are not provided by the current routinely used means, such as KPS. The Mini-Mental Status Exam (MMSE) provides greater sensitivity to patients' differences in neurological status and may be preferable to NFS as an eligibility criteria.

Effects of ethnicity and age or menopause on the remodeling and turnover of iliac bone: implications for mechanisms of bone loss

We measured histologic indices of bone remodeling and turnover separately on the cancellous, endocortical, and intracortical subdivisions of the endosteal envelope, and on the combined total surface, in transiliac bone biopsies obtained after double tetracycline labeling in 142 healthy women, aged 20-74 years, 34 black and 108 white, 61 premenopausal and 81 postmenopausal. The data were analyzed by two-way analysis of variance of the four groups defined by age/menopause and ethnicity and by linear regression of the major variables on age. None of the interaction terms was significant and none of the regression slopes on age differed between blacks and whites, indicating that, as for the previously reported structural indices, the effects of ethnicity and of age/menopause are independent. Accordingly, the data were also analyzed separately for the effect of ethnicity (pre- and postmenopausal combined) and age/menopause (blacks and whites combined). The analyses led to the following conclusions. (1) The geometric mean bone formation rate on the combined total surface was 25% lower in blacks than in whites; other histologic differences between ethnic groups were inconsistent between surfaces. (2) Serum osteocalcin (OC) but not bone-specific alkaline phosphatase (BSAP) was lower by about 15% in blacks than in whites. (3) The lower bone turnover in blacks is most likely in the directed rather than in the stochastic component because of a higher bone mass and consequent reduced susceptibility to fatigue damage. (4) All Class 1 bone formation variables and the three resorption indices were significantly higher in the postmenopausal compared with the premenopausal subjects, reflecting a 33% increase in activation frequency. (5) BSAP, but not OC, was increased relatively more (66%) than the bone formation rate (BFR). Consequently, BSAP is more sensitive to the effects of menopause than OC, but OC is more sensitive to the effects of ethnicity than BSAP. (6) There were highly significant differences between the three subdivisions of the endosteal envelope for every non-cell-related variable. All Class 1 formation variables were highest on the endocortical surface, but the magnitude and pattern of the differences otherwise was inconsistent between variables. The contributions of the different subdivisions to the total bone formation rate were cancellous 54%, endocortical 13%, and intracortical 33%. (7) The previously reported changes in bone surface location, together with the presently reported changes in activation frequency and wall thickness indicated that there was no significant effect of age/menopause on erosion depth on the cancellous and intracortical surfaces but a large increase in erosion depth on the endocortical surface. (8) The increase in bone turnover that results from hormonal changes is most likely in the stochastic rather than in the directed component because it serves no purpose but has harmful effects on skeletal integrity.

Prevalence of intestinal chlamydial infection in pigs in the midwest, as determined by immunoperoxidase staining

OBJECTIVE

To determine prevalence of intestinal chlamydial infection in pigs and to compare prevalence of diarrhea in infected pigs with that in noninfected pigs to evaluate the importance of Chlamydia sp as causes of diarrhea in pigs. ANIMALS AND PROCEDURES: Intestines from 351 sick pigs submitted to 2 veterinary diagnostic laboratories and from 96 healthy pigs that were part of an Escherichia coli susceptibility study were examined by immunoperoxidase staining for chlamydial antigen. The proportion of Chlamydia-infected pigs in each group was calculated and compared. The proportion of Chlamydia-infected pigs with diarrhea was compared with the proportion of noninfected pigs with diarrhea.

RESULTS

15% of the sick and healthy pigs were infected with Chlamydia sp. Prevalence of diarrhea was equal between infected and noninfected pigs. Chlamydia sp were the third most common pathogens identified, and prevalence of chlamydial infection increased after 3 weeks of age.

CONCLUSIONS AND CLINICAL RELEVANCE

Intestinal chlamydiosis is common in commercial pigs, but most, if not all, infections are subclinical Without collaborative evidence, simply identifying Chlamydia sp in feces or the intestinal tract of pigs with enteritis or diseases of other organ systems should not be considered proof that the organism caused the clinical signs of disease.

A Medicaid mental health carveout program: the Massachusetts experience

Private sector contracts with Medicaid mental health programs have the potential to help states offer quality improvements and cost savings for chronically mentally ill populations. A Massachusetts experience illustrates how state agencies, community providers, and a private, mental health management firm collaborated to reduce rising Medicaid mental health and substance abuse costs and improve access and quality of care for Medicaid recipients.

Obstacles to nutrition labeling in restaurants

OBJECTIVE

This study determined the major obstacles that foodservices face regarding nutrition labeling.

DESIGN

Survey questionnaire was conducted in May 1994. In addition to demographic questions, the directors were asked questions addressing willingness, current practices, and perceived obstacles related to nutrition labeling.

SUBJECTS/SETTING

Sixty-eight research and development directors of the largest foodservice corporations as shown in Restaurants & Institutions magazine's list of the top 400 largest foodservices (July 1993).

STATISTICAL ANALYSES PERFORMED

P tests were used to determine significance within a group for the number of foodservices that were currently using nutrition labeling, perceived impact of nutrition labeling on sales, and perceived responsibility to add nutrition labels. Regression analysis was used to determine the importance of factors on willingness to label.

RESULTS

Response rate was 45.3%. Most companies were neutral about their willingness to use nutrition labeling. Two thirds of the respondents were not currently using nutrition labels. Only one third thought that it was the foodservice's responsibility to provide such information. Several companies perceived that nutrition labeling would have a potentially negative effect on annual sales volume. Major obstacles were identified as menu or personnel related, rather than cost related. Menu-related obstacles included too many menu variations, limited space on the menu for labeling, and loss of flexibility in changing the menu. Personnel-related obstacles included difficulty in training employees to implement nutrition labeling, and not enough time for foodservice personnel to implement nutrition labeling.

APPLICATIONS

Numerous opportunities will be created for dietetics professionals in helping foodservices overcome these menu- or personnel-related obstacles.

Crosstalk between G proteins and protein kinase C mediated by the calcium channel alpha1 subunit

The modulation of voltage-dependent Ca2+ channels at presynaptic nerve terminals is an important factor in the control of neurotransmitter release and synaptic efficacy. Some terminals contain multiple Ca2(+)-channel subtypes (N and P/Q), which are differentially regulated by G-protein activation and by protein kinase C (PKC)-dependent phosphorylation. Regulation of channel activity by crosstalk between second messenger pathways has been reported although the molecular mechanisms underlying crosstalk have not been described. Here we show that crosstalk occurs at the level of the presynaptic Ca2(+)-channel complex. The alpha1 subunit domain I-II linker, which connects the first and second transmembrane domains, contributes to the PKC-dependent upregulation of channel activity, while G-protein-dependent inhibition occurs through binding of Gbetagamma to two sites in the I-II linker. Crosstalk results from the PKC-dependent phosphorylation of one of the Gbetagamma binding sites which antagonizes Gbetagamma-induced inhibition. The results provide a mechanism for the highly regulated and dynamic control of neurotransmitter release that depends on the integration of multiple presynaptic signals.

Phosphorylation of linker histones by a protein kinase A-like activity in mitotic nuclei

Micronuclear linker histones of the ciliated protozoan, Tetrahymena thermophila, are extensively phosphorylated in vivo. Each of these polypeptides, alpha, beta, gamma, and delta, contains sites for phosphorylation by cyclic-AMP dependent protein kinase (PKA) but not Cdc2 kinase, and some data have been presented implicating PKA kinase in their phosphorylation in vitro and in vivo (Sweet, M. T., and Allis, C. D. (1993) Chromosoma 102, 637-647; Sweet, M. T., Jones, K., and Allis, C. D. (1996) J. Cell Biol., in press). In this report we have extended these analyses by showing that Cdc2 and PKA kinase are not evenly distributed between micro- and macronuclei. Macronuclei, but not micronuclei, contain a 36-kDa polypeptide that is immunoreactive with p34Cdc2 antibodies. In contrast, a 40-kDa polypeptide is detected with PKA antibodies in micronuclei, that is not detected in macronuclei. In support, extracts from micronuclei, but not macronuclei, contain a kinase activity that resembles some, but not all, characteristics of PKA from other sources. Immunodepletion experiments using anti-PKA antibodies show that a 40-kDa polypeptide can be specifically removed from these extracts with a concomitant loss in kinase activity. Microsequence analyses of delta demonstrate that this linker histone is phosphorylated in vivo on two PKA consensus sequences located in its carboxyl-terminal domain, an optimum PKA consensus sequence, Arg-Lys-Asn-Ser, and a less optimal PKA sequence, Lys-Ser-Ser-Val. Collectively, these results suggest that PKA or a PKA-like kinase is responsible for the phosphorylation of linker histone in mitotically dividing micronuclei. In contrast, macronuclei, which divide amitotically, phosphorylate linker histone H1 using a distinct, Cdc2-like kinase.

Why are you waiting? Formulating an information pamphlet for use in an accident and emergency department

The provision of information to patients and relatives reduced their anxiety and leads to greater understanding of what is happening to them and around them. Supplying information verbally has been shown to be at times fragmented and haphazard, particularly when dealing with worried and anxious patients in a hospital setting. The anxiety generated by injury or illness leading to attendance at Accident and Emergency (A & E) Departments does not lend itself to the use of verbal information. To overcome this an information leaflet was developed to supplement verbal information. It describes the working and geography of the A & E department, in an attempt to improve patients' understanding of how the department works and why they may have to wait. The introduction of the leaflet is to supplement verbal communication. Its use has had a positive effect, dovetailing with verbal communication to improve patients' understanding of why they may have to wait.

Dihydropyrimidine dehydrogenase inactivation and 5-fluorouracil pharmacokinetics: allometric scaling of animal data, pharmacokinetics and toxicodynamics of 5-fluorouracil in humans

The pharmacokinetics of 5-fluorouracil (5-FU) in different animal species treated with the dihydropyrimidine dehydrogenase (DPD) inactivator, 5-ethynyluracil (776C85) were related through allometric scaling. Estimates of 5-FU dose in combination with 776C85 were determined from pharmacokinetic and toxicodynamic analysis.

METHOD

The pharmacokinetics of 5-FU in the DPD-deficient state were obtained from mice, rats and dogs treated with 776C85 followed by 5-FU. The pharmacokinetics of 5-FU in humans were then estimated using interspecies allometric scaling. Data related to the clinical toxicity for 5-FU were obtained from the literature. The predicted pharmacokinetics of 5-FU and the clinical toxicity data were then used to estimate the appropriate dose of 5-FU in combination with 776C85 in clinical trials.

RESULTS

The allometric equation relating total body clearance (CL) of 5-FU to the body weight (B) (CL = 0.47B0.74) indicates that clearance increased disproportionately with body weight. In contrast, the apparent volume of distribution (Vc) increased proportionately with body weight (Vc = 0.58 B0.99). Based on allometric analysis, the estimated clearance of 5-FU (10.9 l/h) in humans with DPD deficiency was comparable to the observed values in humans lacking DPD activity due to genetic predisposition (10.1 l/h), or treatment with 776C85 (7.0 l/h) or (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdUrd, 6.6 l/h). The maximum tolerated dose (MTD) of 5-FU in combination with 776C85 was predicted from literature data relating toxicity and plasma 5-FU area under the concentration-time curve (AUC). Based on allometric analysis, the estimated values for the MTD in humans treated with 776C85 and receiving 5-FU as a single i.v. bolus dose, and 5-day and 12-day continuous infusions were about 110, 50 and 30 mg/m2 of 5-FU, respectively.

DISCUSSION

The pharmacokinetics of 5-FU in the DPD-deficient state in humans can be predicted from animal data. A much smaller dose of 5-FU is needed in patients treated with 776C85.

Effect of ethnicity and age or menopause on the structure and geometry of iliac bone

We measured indices of bone volume (cancellous, cortical) and bone surface (cancellous, endocortical, and intracortical) in intact full-thickness transiliac bone biopsies obtained from 144 healthy women aged 20-74 (35 black and 109 white, 62 premenopausal and 82 postmenopausal). The data were analyzed by two-way analysis of variance of the four groups defined by age/menopause and ethnicity and by linear regression of major variables on age. None of the interaction terms was significant, and none of the regression slopes on age differed between blacks and whites, indicating that the effects of ethnicity and of age/menopause were independent. Accordingly, the data were also analyzed separately for the effects of ethnicity (pre- and postmenopausal combined) and age/menopause (blacks and whites combined). The analyses led to the following conclusions. (1) Blacks have more cancellous and cortical bone than whites in the ilium; the difference was due to thicker trabeculae and thicker cortices with no difference in trabecular number or cortical porosity. (2) The magnitude of the black/white differences was the same throughout the age range covered by the study, indicating differences in peak adult values, not in rates of loss with age. (3) As the result of age/menopause, there were significant reductions in all indices of the amount and structure of bone except for trabecular thickness; the magnitude of the reductions was the same in blacks and whites. (4) Cancellous bone loss was mainly the result of the complete removal of some trabecular elements with increased separation between remaining elements. Cortical bone loss was due to thinning from the endocortical surface with a small but significant contribution from increased cortical porosity, due to an increased number of intracortical canals. These patterns of bone loss were the same in blacks and whites. (5) Although the percentage losses of bone with age/menopause were higher for cancellous than for cortical bone, the absolute amounts of bone lost were about the same for cortical as for cancellous bone. (6) The ratio of surface to tissue volume decreased with age/menopause in cancellous bone but increased in cortical bone; rates of bone loss would change in the same manner if the loss per unit of surface remained constant. (7) The total extent of bone surface in the ilium did not change with age/menopause, so that the surface/volume ratio for the entire bone increased; volumetric bone turnover would increase and bone age decrease if remodeling activity per unit of surface remained constant.

Regulation of GABA level in rat brain synaptosomes: fluxes through enzymes of the GABA shunt and effects of glutamate, calcium, and ketone bodies

Stable isotopes were used to measure both the rate of GABA formation by glutamic acid decarboxylase (GAD) and the rate of utilization by GABA-transaminase (GABA-T). The initial rate of GABA accumulation, determined with either [2-15N]glutamine or [2H5]glutamine as precursor, was 0.3-0.4 nmol/min/mg of protein. Addition of the calcium ionophore A23187 enhanced GAD activity, whereas changes in levels of inorganic phosphate and H+ were without influence. Flux through GABA-T (GABA--> glutamate), measured with [15N]GABA as precursor, was 0.82 nmol/min/mg of protein, whereas the reamination of succinic acid semialdehyde (reverse flux through GABA-T) was almost sixfold faster, 4.8 nmol/min/mg of protein. The rate of GABA metabolism via the tricarboxylic acid cycle was very slow, with the upper limit on flux being 0.03 nmol/min/mg of protein. Addition of either acetoacetate or beta-hydroxybutyrate raised the internal content of glutamate and reduced that of aspartate; the GABA concentration and the rate of its formation increased. It is concluded that in synaptosomes (a) GABA-T is a primary factor in regulating the turnover of GABA, (b) a major regulator of GAD activity is the concentration of internal calcium, (c) GAD in nerve endings may not be saturated with its substrate, glutamate, and the concentration of the latter is a determinant of flux through this pathway, and (d) levels of ketone bodies increase, and maintain at a higher value, the synaptosomal content of GABA, a phenomenon that may contribute to the beneficial effect of a ketogenic diet in the treatment of epilepsy.

Synergy between lysosomotropic amines and cyclosporin A on human T cell responses to an exogenous protein antigen, tetanus toxoid

Previously, it has been shown that the lysosomotropic amine, chloroquine, is effective in the prevention of graft-versus-host disease (GVHD) using murine models. Because chloroquine and hydroxychloroquine suppress MHC class II antigen presentation, their mechanism of action is different to other immune suppressant drugs (cyclosporin A) currently used to control GVHD. It is possible that the use of cyclosporin A and chloroquine in combination may have an additive or synergistic effect on T cell responses to antigens presented in the context of MHC class II. We investigated the effects of chloroquine or hydroxychloroquine in combination with cyclosporin A on human T cell responses in vitro to tetanus toxoid, an exogenous protein antigen dependent on MHC class II presentation for proliferative responses. We demonstrate that similar levels of chloroquine and hydroxychloroquine suppress human T cell responses to tetanus toxoid and that the use of either agent in combination with cyclosporin A results in synergistic suppression. Evaluation for a direct effect by the lysosomotropic amines on T cells, in the absence of antigen presenting cells, revealed that there was inhibition of T cell responses but only at high concentrations. No significant decrease or increase was seen in surface MHC II or invariant chain expression or in cytoplasmic invariant chain after exposure to chloroquine. Thus, lysosomotropic amines in combination with cyclosporin A are synergistic in suppression of T cell proliferation. Use of these agents in combination with cyclosporin A may improve control of graft-versus-host disease.

Does storage of sputum specimens adversely affect culture results?

It has been recommended that samples submitted for microbiological examination should be retained for 48 hours after issue of the final report. In order to ascertain whether reproducible results could be achieved following storage of sputum specimens, two laboratories each re-cultured 100 samples 48 hours after their report had been issued and a further laboratory re-cultured 100 samples 48 hours after receipt. Discordant results were obtained in only 5-25% of specimens, indicating that potential respiratory pathogens could survive storage.

Limitation of glycolysis by hexokinase in rat brain synaptosomes during intense ion pumping

Incubation of rat brain synaptosomes under conditions of either increased energy utilization (addition of Na+ channel opener, veratridine, or ionophores, monensin and nigericin) or inhibition of oxidative phosphorylation (addition of rotenone), or a combination thereof, decreased [ATP], increased [ADP] and stimulated glycolysis. The rates of lactate generation were linear over a 15-min interval in the presence of rotenone alone but decreased in the other two conditions. During the first 5 min, the amount of lactate formed with veratridine, monensin or nigericin was as high or higher than with rotenone, but it was lower in the last 10 min. With a combination of one of the stimulators of ion movements and rotenone the rate of glycolysis was always markedly lower than with each compound added singly. The stimulated rates of lactate formation correlated positively with the synaptosomal content of [ATP]. After 15 min, [ATP] was 0.9-1.0 nmol/mg with rotenone, 0.5-0.9 nmol/mg with veratridine (or ionophores), and <0.3 nmol/mg with a combination of the two. Under the conditions used, calcium did not affect glycolytic activity directly. The Lineweaver-Burk plot of the rate of lactate formation against [ATP] yielded a straight line with a Km for ATP of about 0.1 mM, which is very similar to the Km for this nucleotide of brain hexokinase bound to mitochondria. In C6 cells glycolytic rate measured with a combination of an ionophore and rotenone was higher than with each of these compounds added singly while [ATP] never declined below about 9 nmol/mg prot. It is concluded that in synaptosomes, the high rate of energy utilization required for intense ion movement decreases [ATP] to a level that limits hexokinase activity kinetically. This may contribute to a reduction in the rate of glycolysis and hence energy production in brain hypoxia and ischemia.

Situational feature recognition in schizophrenic outpatients

Previous research has suggested that patients with schizophrenia are significantly better at identifying relatively concrete features that describe social situations (e.g., actions and roles) than more abstract features (e.g., rules and goals). Because participants in the earlier research were all inpatients, the results may have been confounded by various factors that are commensurate with a hospital stay. Thirty-one patients with DSM-III-R diagnoses of schizophrenia or schizoaffective disorder and 39 normal volunteers completed the Situational Feature Recognition Test to determine whether they also showed the differential deficit. Results showed that the outpatient group was, indeed, less symptomatic than the inpatient group; outpatients also showed better overall feature recognition than inpatients. Schizophrenic outpatients and normal volunteers are significantly better at identifying concrete features than abstract features. Additional analyses suggested that the differential deficit in outpatients is due, in part, to their disorder. Implications for the remediation of social functioning deficits are discussed.

Emergency echocardiography telemedicine: an efficient method to provide 24-hour consultative echocardiography

OBJECTIVES

This study sought to assess the clinical utility of interpreting emergency echocardiograms after regular working hours through a telemedicine connection to on-call cardiologists.

BACKGROUND

Physician interpretation of emergency echocardiograms is often delayed during weekends, evenings or night hours. This delay places undue responsibility on less qualified personnel to interpret echocardiograms of vital importance.

METHODS

Digital quad-screen cine-loop format was transmitted over standard telephone lines. Clinical data and conventional and telemedicine interpretations were collected prospectively for 187 emergent or semiemergent tele-echocardiograms after regular working hours.

RESULTS

Indications for the echocardiogram included assessment of left ventricular function, ischemia, pericardial effusion, valvular disease, heart donor status and arrhythmia. Three off-site echocardiographers received the standard echocardiogram and spectral, gray-scale and color flow Doppler images in cineloop format using a laptop computer. Laptop interpretation showed 19 technically limited studied, 153 abnormal studies and 54% with wall motion abnormalities. Overall mean agreement rate between telemedicine laptop interpretation and conventional workstation interpretation performed in blinded manner for serious disorders with classic echocardiographic findings (pulmonary hypertension, left ventricular thrombus, aortic dissection, severe valvular insufficiency and large pericardial effusion) was 99.0% (95% confidence interval [CI] 96% to 99%). For serious wall motion abnormalities, the agreement rate was 96.3% (95% CI 92% to 99%). The following mean times elapsed after completion of the echocardiogram: to laptop fax report, 2.14 (range 10 min to 8 h); to dictation of videotape, 11.74 h (p < 0.001); to transcription of videotape diction, 56.6 h (p < 0.0001).

CONCLUSIONS

After-hours emergency echocardiography telemedicine using a laptop computer is more rapid than scheduled conventional interpretation from a videotape workstation, yet diagnostic accuracy is comparable.

Attention and regional cerebral blood flow in posttraumatic stress disorder patients with substance abuse histories

Performance on an attentional task was assessed in posttraumatic stress disorder patients with substance abuse histories (PTSD-SA). Positron emission tomography (PET) was used to measure concurrent regional cerebral blood flow (rCBF). Eight male PTSD-SA patients and eight normal subjects each received three serial PET scans with 15O-labeled water under the following conditions: (1) resting, (2) auditory continuous performance task (ACPT1), and (3) repeat auditory task (ACPT2). PTSD-SA patients made more errors of commission on the ACPT than normal subjects. Examination of right frontal and parietal cortex ACPT task substrates revealed decreased parietal blood flow in PTSD-SA, which may represent a pathophysiology for poor attentional task performance in PTSD-SA. Attentional problems may underlie other symptomatology in PTSD.

Neuronal metabolism of branched-chain amino acids: flux through the aminotransferase pathway in synaptosomes

The metabolism of branched-chain amino acids (BCAAs) was studied in cortical synaptosomes. With [15N]leucine (1 mM) as precursor, the cumulative appearance of 15N in [15N]glutamate and [15N]aspartate was 0.2 nmol/min/mg of protein without supplemental alpha-ketoglutarate and 0.3 nmol/min/mg of protein in the presence of alpha-ketoglutarate (0.5 mM). The BCAA amino-transferase reaction also proceeded in the "reverse" direction [alpha-ketoisocaproate (KIC) + glutamate-->leucine + alpha-ketoglutarate]. This was documented by incubating synaptosomes with [15N]glutamate and measuring the formation of [15N]leucine. Without KIC in the medium, the rate of [15N]leucine production was 0.13 nmol/min/mg of protein. In the presence of 25 microM KIC the rate was 0.79 nmol/min/mg of protein and even greater (1.0 nmol/ min/mg of protein) in the presence of 500 microM KIC. The reamination of KIC was two- to threefold faster with [2-15N]glutamine as precursor compared with [15N]-glutamate. The ketoacid of valine, alpha-ketoisovalerate (KIV), was reaminated to [15N]valine at a rate comparable to that observed with respect to KIC. The BCAA transaminase mediated not only the bidrectional transfer of amino groups between leucine or valine and glutamate, but also the direct transfer of nitrogen between leucine and valine. This was ascertained in studies in which the incubation medium was supplemented with either [15N]leucine and KIV or [15N]valine and KIC (amino acids at 1 mM and ketoacids at 25 or 500 microM). The rate was faster in the direction of leucine formation at both the lower (6.1-fold) and higher (1.7-fold) KIC concentration. It is suggested that in synaptosomes the BCAA transaminase (a) functions predominantly in the direction of leucine formation and (b) maintains a constant ratio of BCAAs and ketoacids to one other.

A seasonal staffing model

The staffing of a nursing unit provides a unique challenge when that unit experiences significant seasonal fluctuations in census. Although overtime, perdiem, or agency personnel are staffing alternatives to meet seasonal fluctuations in census, they are costly alternatives that are not the most efficient use of human resources. The authors present a seasonal staffing model that reallocates employee work hours in a pattern that closely matches the seasonal work load trends of the department.

The feasibility of dobutamine stress echocardiography in the emergency department with telemedicine interpretation

Dobutamine stress echocardiography (DSE) was performed on 26 patients admitted for chest pain deemed at low risk for myocardial infarction. Pharmacologic stress in the emergency department on a 24-hour basis was administered by nurses and echocardiographic ultrasonographers with electrocardiograms and echocardiograms being interpreted through telemedicine relay by an off-site cardiologist. Target heart rate was achieved in 84% of patients with an average peak dobutamine dose of 48 microg/kg/min. Echocardiographic transmission to the cardiologist over standard telephone lines took 9 minutes per quad-screen cine-loop display. The entire protocol added 2.2 hours to the emergency room evaluation. The one patient out of 26 who had incipient myocardial infarction was diagnosed by resting echocardiography. The remaining 25 patients were found clinically to have no infarction or ischemia. Of these, 22 out of 25 had normal DSE in the emergency department; three had wall motion abnormalities on peak stress images. Another three patients had other cardiac diseases documented by echocardiography. Evaluation of chest pain on a 24-hour basis with DSE with telemedicine interpretation appears to be a rapid and safe means of screening patients at low risk in the emergency department. Further experience with this modality is needed before all patients should be enrolled or early discharge of patients on the basis of DSE can be advised.

Function and medical comorbidity in south Texas nursing home residents: variations by ethnic group

OBJECTIVE

To evaluate differences in functional status and burdens of medical conditions in Mexican American and non-Hispanic white nursing home residents.

DESIGN AND SETTING

Cross-sectional survey of 17 nursing homes in south Texas.

PARTICIPANTS

A total of 617 older nursing home residents, of whom 366 were Mexican American and 251 were non-Hispanic white.

MEASURES

Activities of Daily Living (ADL) status abstracted from standard nurses notes and Burden of Disease abstracted from medical records.

RESULTS

Mexican American residents had greater numbers of ADL dependencies and poorer overall ADL scores than non-Hispanic white residents. This poor functioning was not explained by age, gender, or marital or educational status. The average number of medical conditions was greater, and specific conditions, such as cerebrovascular disease, recent acute infections, diabetes, hypertension, and anemia, were more common in Mexican American residents compared with non-Hispanic white residents. In models relating function with medical conditions and ethnic group, ADL scores and dependencies were significantly related to bowel and bladder incontinence, cerebrovascular disease, dementia, recent infections, and skin decubiti, but not to ethnic group.

CONCLUSION

Mexican American nursing home residents are more functionally dependent than non-Hispanic white residents. The difference in function is explained by a greater burden of medical conditions in the Mexican American residents.

Symptomatology and energy intake during the menstrual cycle in smoking women

This study extends our understanding of smoking behavior, withdrawal, and premenstrual symptomatology in smoking women, as well as energy intake as a function of cycle phase. Thirty-two women age 18 to 40 years, smoking ad lib, were followed for an average of two menstrual cycles with hormonal verification. Withdrawal and premenstrual symptomatology as well as energy intake were reported during the follicular (F), luteal (L), and late luteal (LL) cycle phases. Both premenstrual symptomatology and withdrawal symptomatology were higher during the LL phase. Subject response on measurements of craving, irritability, restlessness, increased appetite, and depressed mood tended to be higher in the LL phase. Energy intake did not vary as a function of cycle phase. Participants perceived that they smoked more and had increased appetite in the LL phase but related measurements did not confirm this. Premenstrual and withdrawal symptoms are highly correlated and one needs to be cautious in interpreting cycle effects on withdrawal. Overall symptomatology seems to be lower during the F phase, indicating that this may be a more opportune time for women to quit smoking.

Effects of NO-generating compounds on synaptosomal energy metabolism

The effects of nitroprusside and S-nitrosocysteine, compounds that generate nitric oxide (NO), on synaptosomal energy-producing pathways and energy level were investigated. The decrease in respiration was much faster and more pronounced with S-nitrosocysteine than with nitroprusside. S-Nitrosocysteine, at 10 microM, inhibited by 80% respiration with glucose and succinate (plus rotenone) in intact synaptosomes and with ascorbate/cytochrome c in broken preparations. Oxygenated hemoglobin reversed and/or prevented the inhibition, whereas glutathione (GSH) prolonged it. Under aerobic conditions, the synaptosomal energy level (creatine phosphate/creatine and ATP/ADP ratios) was reduced by the presence of S-nitrosocysteine, whereas lactate generation was enhanced. The effects on energy parameters were greater at 5 min than at 15 min of incubation and were more pronounced in the presence of GSH. Under strictly anaerobic conditions, lactate production was reduced by the NO-generating compounds in a concentration-dependent manner. It is concluded that (a) inhibition of oxidative phosphorylation by NO leads to a fall in the synaptosomal energy level, which in turn stimulates glycolysis; (b) glycolysis can be inhibited by higher concentrations of the radical; and (c) inhibitory effects on the energy-generating pathway and ATP level could contribute to NO toxicity under some in vivo situations.

Metabolic and energetic changes during apoptosis in neural cells

Changes in cellular energetic and metabolic parameters were analyzed at several time points during apoptosis of differentiated PC12 cells following removal of nerve growth factor (NGF). As approximately 60% of the population died during the period of study (24 h), most of the measured metabolic indicators declined over time. However, this decline paralleled the overall decrease in cellular viability, suggesting that, in individual cells, a compromised metabolic state occurred suddenly and very late in the death process. For example, when expressed as a function of viable cells, protein and RNA synthesis did not decrease until 24 h. Glucose utilization in live cells was never significantly reduced relative to control levels; lactate production decreased slightly within 4-8 h after NGF removal, but eventually rebounded to 122% of control levels by 24 h. ATP levels dropped 27% in an early predeath period, but then returned to near control levels (on a per-live-cell basis) once the population actively began to die. The ATP/ADP ratio remained at least 84% of control throughout. UTP/UDP and GTP/GDP ratios did not change significantly at any time point.

Research into research practice

Since the Briggs report of 1972, the debate over whether nursing is a researched based profession continues. This paper attempts to establish whether research performed by practitioners in their own field is being directly utilised in practice. The paper describes a small scale study of registered nurses (n = 22) who have completed the Professional Studies 2 Accident & Emergency module, focusing on the utilisation of their action research and the factors influencing the outcome of its use. Data was collected by self-report questionnaire. The results of the study indicate that many action research projects are not being formally utilised within the clinical area. The main factor stated is the lack of research culture within units, underpinned by a lack of managerial and peer support for research studies. Despite this, research is being utilised, but only by the individuals who conducted it. The results suggest that greater integration between the college of nursing, management and the student is required to improve research utilisation in the clinical area.

Single-word auditory stimulation and regional cerebral blood flow as studied by SPECT

Single photon emission computed tomography (SPECT) examined changes in regional cerebral blood flow (rCBF) induced by passive auditory single-word stimulation. A split-dose SPECT technique was used between resting and activated states, in which a smaller amount of ligand (99m technetium hexamethyl propyleneamine oxide, HMPAO) was given with the first scan, accompanied by a prolonged scan time. A larger amount of ligand was given with the second scan, accompanied by a shorter scan time. This split-dose SPECT technique has met with previous success for other activation tasks. The brain regions of interest (ROIs) in this study were selected from ROIs previously found to be activated by passive auditory single-word stimulation and not by non-word stimuli in positron emission tomography (PET) rCBF studies. This study thus tested the sensitivity of SPECT with HMPAO to detect brain activation with a stimulus previously demonstrated to elicit changes in rCBF with PET. However, no significant difference was detected between resting and activated states in this study. Thus, SPECT was not as sensitive as PET in this activation task. Since SPECT is a less costly and more widely available modality to study brain activation than PET, it is important to delineate its potential capacities to maximize the efficiency of future research in this field.

Molecular detection of a common mutation in coagulation factor V causing thrombosis via hereditary resistance to activated protein C

More than half of all patients with familial or recurring venous thrombosis have hereditary resistance to activated protein C (HRAPC) as the result of specific missense mutation in the gene for coagulation factor V. Because the mutant factor Va (with an Arg to Gln substitution at codon 506) cannot be cleaved and inactivated by activated protein C, carriers of this mutation are at significantly increased risk of venous thrombosis. We have recently introduced a direct polymerase chain reaction (PCR)-based clinical diagnostic test for the factor V codon 506 mutation based on the destruction of an Mnl I restriction site by the causative nucleotide substitution. To assess the accuracy of this PCR-based assay, we compared a functional clotting time test for HRAPC with the direct mutation test. Of 47 patients dually tested, only five had discrepant values for the functional test versus the DNA test. Either of these two complementary assays is useful for the accurate diagnosis of HRAPC. The DNA-based test is, however, specifically recommended for evaluation of anticoagulated patients or patients with borderline functional tests and confirmation of genotype in HRAPC families. In an additional analysis of 287 normal individuals, we found an extremely high prevalence of the mutated codon 506 allele-- approximately 4% in each of two different populations. The absence of disease in the majority of heterozygous carriers suggests that symptomatic thrombosis requires the simultaneous presence of both a mutated factor V protein and additional synergistic factors.

Student nurses' perceptions of accident and emergency nursing: do they match the reality?

This study explores student nurses' perceptions of, and attitudes to, working in an Accident and Emergency (A & E) department prior to allocation there. An assessment of the students' actual experience within the department was then taken. This allowed the students' perceptions to be compared with the reality of the work. The sample consisted of all students training for part 10 of the register who were allocated to the unit over a 4-week period (n = 22). Data was collected by two self completion questionnaires, one given pre-allocation the second post-allocation, a 100% response rate was achieved for each. The results of the study indicate that students' perceptions of the A & E department do not match the reality of the work involved. These perceptions may cause increased anxiety and apprehension for students before they start in the department and this may hinder clinical learning. The results suggest that appropriate preparation prior to the period of clinical experience may help alleviate these difficulties.

Analysis of sevoflurane degradation products in vapor phase samples

Sevoflurane degradation products were measured by GC-flame ionization detection in vapor phase samples using manual and automated injection methods. Sample handling techniques allowed the transfer and storage of samples for up to 72 h. Compound A, fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether, was the major vapor phase degradation product formed in simulated clinical conditions. Recoveries of 4-32 ppm (v/v) compound A concentrations using the manual method were in the range of 88-117% (n = 12, mean = 102%, R.S.D. = 9%).

Overexpression of the human NFM subunit in transgenic mice modifies the level of endogenous NFL and the phosphorylation state of NFH subunits

Neurofilaments (NFs), the major intermediate filaments of central nervous system (CNS) and peripheral nervous system (PNS) neurons, are heteropolymers formed from the high (NFH), middle (NFM), and low (NFL) molecular weight NF subunits. To gain insights into how the expression of NF subunit proteins is regulated in vivo, two transgenes harboring coding sequences for human NFM (hNFM) with or without the hNFM multiphosphorylation repeat domain were introduced into mice. Expression of both hNFM constructs was driven by the hNFM promoter and resulted in increased levels of hNFM subunits concomitant with an elevation in the levels of mouse NFL (mNFL) proteins in the CNS of both lines of transgenic mice. The increased levels of mNFL appear specific to NFM because previous studies of transgenic mice overexpressing either NFL or NFH did not result in increased expression of either of the other two NF subunits. Further, levels of the most heavily phosphorylated isoforms of mouse NFH (mNFH) were reduced in the brains of these transgenic mice, and electron microscopic studies showed a higher packing density of NFs in large-diameter CNS axons of transgenic versus wild-type mice. Thus, reduced phosphorylation of the mNFH carboxy terminal domain may be a compensatory response of CNS neurons to the increase in NFs, and reduced negative charges on mNFH sidearms may allow axons to accommodate more NFs by increasing their packing density. Taken together, these studies imply that NFM may play a dominant role in the in vivo regulation of the levels of NFL protein, the stoichiometry of NF subunits, and the phosphorylation state of NFH. NFM and NFH proteins may assume similar functions in regulation of NF packing density in vivo.

An n-allele model for progressive amplification in the FMR1 locus

An n-allele model is developed for the FMR1 locus, which causes the fragile X syndrome, where n is the number of triplet repeats in the first exon. Frequencies in the general population and in index families are used to generate an n to n + delta transition matrix that predicts specific risks in satisfactory agreement with observation. However, until sequencing distinguishes between stable and unstable alleles with the same value of n, it is premature to infer whether allelic frequencies at the FMR1 locus are at equilibrium or, as some have suggested, are evolving toward higher frequencies of the pathogenic allele.

Celiac sprue in an asymptomatic elderly man

The authors discuss the case of an asymptomatic patient with celiac sprue presenting with hematologic abnormalities on screening laboratory examination. The patient was initially treated for vitamin B-12 and folate deficiency, and subsequently for iron deficiency with limited success until the diagnosis was established. The absence of such classic features of celiac disease as steatorrhea and diarrhea is not an uncommon presentation. Unexplained iron deficiency should alert the clinician to the possibility of celiac sprue.

Molecular genetics in pediatric training: how much do we really know?

A questionnaire was designed to assess the degree of knowledge among 44 residents and medical students in a pediatric residency program about recent advances in medical genetics. The mean score was 40% (4 correct answers per individual). There were no significant differences among the groups. The mean number of correct responses to each question was 13, but topics that had been highly publicized, especially in the lay press, were associated with more correct answers. Among residents and medical students, knowledge of the exact genetic defects of inherited diseases and their implications at the molecular and clinical levels may be limited.

Recombinant endotoxin neutralizing protein improves survival from Escherichia coli sepsis in rats

OBJECTIVE

A recombinant endotoxin neutralizing protein was evaluated for its ability to ameliorate the effects of Escherichia coli sepsis in rats.

DESIGN

Prospective, controlled animal trial.

SETTING

Hospital animal research laboratory.

SUBJECTS

Wistar rats, treated with gentamicin 1 hr after challenge with intraperitoneal E. coli O18ac.

INTERVENTIONS

The animals received a recombinant endotoxin neutralizing protein, in doses of 5, 25, or 50 mg/kg, either 30 or 60 mins after challenge; controls received saline.

MEASUREMENTS AND MAIN RESULTS

Geometric mean serum endotoxin concentrations in endotoxin neutralizing protein-treated animals did not differ from control animals. Tumor necrosis factor concentrations in animals treated with endotoxin neutralizing protein 30 mins after challenge were significantly lower than controls. Animals treated with 25 or 50 mg/kg of endotoxin neutralizing protein 30 mins after E. coli challenge had significant improvements in survival compared with controls. Animals treated with 50 mg/kg of endotoxin neutralizing protein 60 mins after E. coli challenge had significant improvements in survival compared with controls.

CONCLUSION

Endotoxin neutralizing protein significantly reduces mortality from Gram-negative sepsis in an antibiotic-treatment model of E. coli peritonitis and bacteremia in rats, mediated by a neutralization of the biological effects of endotoxin.

Monoclonal anti-dipeptide antibodies cross-react with detyrosinated and glutamylated forms of tubulins

Two monoclonal antibodies, GLU-1 and A1.6, raised against gamma-L-glutamyl-L-glutamic acid dipeptide (Glu-Glu) and Ca(2+)-dependent ATPase from Paramecium, respectively, recognized the dipeptide Glu-Glu sequence. Whereas the antibodies immunofluorescently stained very few, if any, cytoskeletal fibers in cultured mammalian cells, almost all interphase as well as mitotic spindle microtubules became visible after treatment of cells with carboxypeptidase A. Immunoblot analysis demonstrated intense cross-reaction of the antibodies to the alpha-tubulin subunit. alpha-Tubulin isotypes produced as fusion proteins in bacteria were labeled by both the antibodies only when the proteins did not contain a tyrosine residue at the C terminus, indicating that GLU-1 and A1.6 specifically recognize the detyrosinated form of alpha-tubulin. When microtubule protein purified from brain was probed, not only alpha-but also, to a lesser extent, beta-tubulin were revealed by the dipeptide antibodies. A synthetic tripeptide YED containing one glutamyl group linked to the second residue of the peptide via the gamma position was also recognized by the antibodies. Since this peptide sequence corresponds to the amino acid sequence of polyglutamyated class III beta isotype at amino acid position 437 to 439, it is suggested that GLU-1 and A1.6 are able to recognize the glutamylated form of beta-tubulin. These results indicate that the C-terminal Glu-Glu sequence displays strong antigenicity, and the antibodies recognize the sequence present in the C terminus of the detyrosinated form of alpha-tubulin and the glutamyl side chain of beta-tubulin. Particularly strong immunoreaction was detected with ciliary and flagellar microtubules; thus, stable axonemal microtubules appear to be rich in post-translationally modified tubulin subunits.

Tricarboxylic acid cycle in rat brain synaptosomes. Fluxes and interactions with aspartate aminotransferase and malate/aspartate shuttle

The flux through different segments of the tricarboxylic acid cycle was measured in rat brain synaptosomes with gas chromatography-mass spectrometry using either deuterated glutamine or [13C]aspartate. The flux between 2-oxoglutarate and oxaloacetate was estimated to be 3.14 and 4.97 nmol/min/mg protein with and without glucose, respectively. These values were 3-5-fold faster than the flux between oxaloacetate and 2-oxoglutarate (0.92 nmol/min per mg protein) measured in the presence of glucose. The pattern of intermediates labeling suggests that the overall rate-controlling reaction involves either citrate synthase or pyruvate dehydrogenase but not 2-oxoglutarate or isocitrate dehydrogenase. The enrichment in [3,3,4,4-2H4]glutamate from [2,3,3,4,4-2H5]glutamine was as rapid as in [2,3,3,4,4-2H5]glutamate, which indicates that the aspartate aminotransferase reaction is severalfold faster than the flux through the tricarboxylic acid cycle. [13C]Aspartate was rapidly converted to [13C]malate, suggesting that in intact synaptosomes aspartate entry into the mitochondrion is very slow. The finding that aspartate is taken up by mitochondria as malate, along with the observed high enrichment in [3-2H]malate (from [2,3,3,4,4-2H5]glutamine), is consistent with the substantial synaptosomal activity of the malate/aspartate shuttle.

Glutamine catabolism by heart muscle: regulation of phosphate-activated glutaminase by ATP, citrate, and chloride

Production of glutamate from glutamine by rat heart mitochondria was stimulated by citrate and ATP in a dose-dependent manner. Citrate required phosphate for manifestation of its stimulatory action, whereas ATP enhanced glutaminase activity with and without phosphate. At low concentrations (1-50 mM) ATP was more potent than citrate, whereas the opposite was true at high (50-150 mM) levels of these anions. Both citrate and ATP decreased the concentration of phosphate required for half-maximal stimulation of glutamate production (EC50) and reduced the value of the Hill coefficient. Phosphate lowered the EC50 for ATP. Chloride and other anions of chaotropic series inhibited glutamine catabolism, most likely by causing depolymerization of the enzyme. Rupture of mitochondrial membranes by freeze-thawing decreased the responsiveness of glutaminase to phosphate, ATP, and especially to citrate but it did not alter the inhibition of the enzyme by chaotropic anions. It is concluded that phosphate, ATP, and citrate act in concert to modulate glutaminase activity in heart in vivo. Chloride, which exhibits a small inhibitory effect at a concentration normally present in cardiac muscle, may assume a greater regulatory role in situations accompanied by a rise in the internal level of this anion.

Gene organization of the pregnancy-specific glycoprotein region on human chromosome 19: assembly and analysis of a 700-kb cosmid contig spanning the region

The pregnancy-specific glycoprotein (PSG) gene family consists of 11 closely related genes that form a subgroup of the carcinoembryonic antigen (CEA) gene family on 19q13.2. Using a high-resolution restriction fragment fingerprinting technique, we have assembled 256 cosmids from the PSG region into a single 700-kb contig. Fluorescence in situ hybridization to sperm pronuclei and cosmid walking experiments indicated that this PSG contig was directly telomeric of CGM8 at the telomeric end of the CEA subgroup gene cluster. Detailed restriction mapping and hybridization with gene-specific probes indicated that the order of the 11 Previously identified PSG genes is cen-PSG3-PSG8-PSG12-PSG1-PSG6-PSG7-+ ++PSG13-PSG2-PSG5-PSG4-PSG11-tel. The CEA subgroup gene CGM11 is located at the telomeric end of the PSG gene cluster. The PSG genes are all oriented in tandem with the 5'-3' direction of transcription from telomere to centromere. The detailed map also led to the identification of seven new CEA family genes in this region. One of these (CGM12), located between CGM8 and PSG3, is a member of the CEA subgroup. The remaining six (CGM13 through CGM18) are interspersed among the PSG genes and appear to form a third distinct subgroup within the CEA gene family.

Effects of 3-nitropropionic acid on synaptosomal energy and transmitter metabolism: relevance to neurodegenerative brain diseases

3-Nitropropionic acid (3-NPA) inhibited synaptosomal respiration in a dose-dependent manner; the degree of inhibition by the same concentration of the compound was greater, however, when respiration was stimulated by concomitant increase in ATP usage. The most rapid event after addition of 3-NPA was a decrease in [creatine phosphate]/[creatine] ([CrP]/[Cr]) and an increase in [lactate]/[pyruvate]. A fall in [ATP]/[ADP] and [GTP]/[GDP] was initially less pronounced but closely followed that in [CrP]/[Cr]. In the absence of glutamine, 3-NPA caused a pronounced decrease in internal aspartate level and a small reduction in glutamate concentration, whereas [GABA] rose; the sum of these three amino acids inside synaptosomes fell, but there were no increases in their external levels. With glutamine in the medium, the reduction in intrasynaptosomal aspartate was accompanied by increases in intrasynaptosomal glutamate and GABA. The external concentration of glutamate rose substantially in the presence of the inhibitor. 3-NPA had no effect on basal release of either glutamate (and GABA) or biogenic amines but increased efflux occurring upon addition of nonsaturating concentrations of the depolarizing agents veratridine and KCl. The results allow the following predictions with respect to the behavior of brain metabolism in neurodegenerative diseases that involve restrictions of mitochondrial function: (1) The extent of inhibition of mitochondrial ATP generation is expected to be greater in cells with high energy demand. The earliest signs of impairment of the respiratory chain function are a fall in [PCr]/[Cr] (or a rise in [Pi]/[CrP]) and an increase in [lactate]/[pyruvate]. (2) A fall in [GTP]/[GDP] can limit protein synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of a curriculum model in an Accident and Emergency Department

This paper describes the adaptation and use of Beattie's curriculum model in an Accident and Emergency (A/E) Department. The rationale behind the undertaking was to reduce the incongruity between the triangle of the college, A/E and the student that creates the theory-practice gap in the context of A/E nursing. The article discusses firstly the decision to use a curriculum model. Secondly the reasons for the choice of model and the factors influencing that choice are discussed. The difficulties in applying the model and teaching methods that may be employed are examined. Student evaluation and the difficulties encountered in implementing the model is the final avenue explored. The article concludes that the strength of Beattie's model in A/E lie in its eclecticism. By combining all four approaches, the practical and theoretical contexts become integrated and in doing so reduce the theory/practice gap between A/E, the college and the student. It also provides a sense of balance for both student and teacher alike, amalgamating the four design briefs with the differing teaching methods thus catering for both group and individual student's differing learning styles.