An updated view of plasmid conjugation and mobilization in Staphylococcus

The horizontal gene transfer facilitated by mobile genetic elements impacts almost all areas of bacterial evolution, including the accretion and dissemination of antimicrobial-resistance genes in the human and animal pathogen Staphylococcus aureus. Genome surveys of staphylococcal plasmids have revealed an unexpected paucity of conjugation and mobilization loci, perhaps suggesting that conjugation plays only a minor role in the evolution of this genus. In this letter we present the DNA sequences of historically documented staphylococcal conjugative plasmids and highlight that at least 3 distinct and widely distributed families of conjugative plasmids currently contribute to the dissemination of antimicrobial resistance in Staphylococcus. We also review the recently documented “relaxase-in trans” mechanism of conjugative mobilization facilitated by conjugative plasmids pWBG749 and pSK41, and discuss how this may facilitate the horizontal transmission of around 90% of plasmids that were previously considered non-mobilizable. Finally, we enumerate unique sequenced S. aureus plasmids with a potential mechanism of mobilization and predict that at least 80% of all non-conjugative S. aureus plasmids are mobilizable by at least one mechanism. We suggest that a greater research focus on the molecular biology of conjugation is essential if we are to recognize gene-transfer mechanisms from our increasingly in silico analyses.

Effectiveness of the Kids in Control of Food (KICk-OFF) structured education course for 11-16 year olds with Type 1 diabetes

AIM

To assess the effect of a 5-day structured education course (Kids in Control of Food; KICk-OFF) on biomedical and psychological outcomes in young people with Type 1 diabetes.

METHODS

This was a cluster-randomized trial involving 31 UK paediatric centres. Participants were recruited prior to stratified centre randomization. Intervention centres delivered KICk-OFF courses, whereas control centres delivered usual care. Participants were 11-16 years of age and had Type 1 diabetes for at least one year. The KICk-OFF course was delivered by trained educators to eight participants per course. Glycaemic control and quality of life were measured at baseline, 6, 12 and 24 months. Secondary outcomes were hypoglycaemia, ketoacidosis, fear of hypoglycaemia and diabetes self-efficacy.

RESULTS

Three hundred and ninety-six participants provided baseline data (199 intervention and 197 control). At 6 and 12 months the intervention group showed significantly improved total generic quality of life scores compared with controls (baseline: 80 vs. 82; 6 months: 82 vs. 82; P = 0.04). Across the whole intervention group mean HbA1c levels were not significantly different from controls; baseline HbA1c mean (95% confidence interval), 78 mmol/mol (75-81) vs. 76 mmol/mol (74-79) [9.3% (9-9.6%) vs. 9.1% (8.9-9.4%); 24 months: 77 mmol/mol (74-79) vs. 78 mmol/mol (75-81) (9.2% (8.9-9.4%) vs. 9.3% (9-9.6%)], adjusted mean difference, -2.0 mmol/mol (6.5-2.5) [2.3% (-2.7% to 2.4%)], P = 0.38.

CONCLUSIONS

Attending a KICk-OFF course was associated with significantly improved total quality of life scores within 6 months. Glycaemic control, as measured by HbA1c , was no different at 24 months. (Clinical Trial Registry No: ISRCTN3704268).

Prognostic indicators of mortality of mechanically ventilated patients with acute leukemia in a comprehensive cancer center

BACKGROUND

The prognosis for adult acute leukemia patients that require intensive care unit (ICU) admission and invasive mechanical ventilation is poor. We aimed to identify prognostic indicators of 30-day hospital mortality in adult patients who had acute leukemia and respiratory failure, who had received invasive mechanical ventilation in the ICU but who had not received blood and marrow transplantation, were not admitted due to cardiopulmonary arrest or myocardial infarction and, had not recently undergone surgery.

METHODS

In this case-control study, we retrospectively reviewed the medical records of relevant patients >16 year old who had been admitted to the ICU at our institution over a 4-year period. The main outcome measure was 30-day hospital mortality. Univariate and multivariate analyses were conducted to determine significant predictors of death.

RESULTS

For the 167 patients meeting our eligibility criteria, the median age was 61 years. The majority was admitted due to respiratory insufficiency/failure (69%). The 30-day hospital mortality rate was 62%. Independent predictors of 30-day hospital mortality were advanced disease status (odds ratio [OR]=3.34; 95% confidence interval [CI], 1.65-6.77) and increased organ failure at the time of intubation (OR=1.17; 95% CI, 1.03-1.33) per point increase in the SOFA score. Patients who had received endotracheal intubation within the first 24 h of ICU admission were less likely than others to die (OR=0.46, 95% CI, 0.23-0.91) within the next 30 days after admission to the hospital.

CONCLUSION

Advanced disease status and elevated SOFA scores at intubation are strong predictors of 30-day mortality in patients with acute leukemia and respiratory failure. The protective effect of early endotracheal intubation warrants further investigation.

Matrigel basement membrane matrix influences expression of microRNAs in cancer cell lines

Matrigel is a medium rich in extracellular matrix (ECM) components used for three-dimensional cell culture and is known to alter cellular phenotypes and gene expression. microRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression and have roles in cancer. While miRNA profiles of numerous cell lines cultured on plastic have been reported, the influence of Matrigel-based culture on cancer cell miRNA expression is largely unknown. This study investigated the influence of Matrigel on the expression of miRNAs that might facilitate ECM-associated cancer cell growth. We performed miRNA profiling by microarray using two colon cancer cell lines (SW480 and SW620), identifying significant differential expression of miRNAs between cells cultured in Matrigel and on plastic. Many of these miRNAs have previously been implicated in cancer-related processes. A common Matrigel-induced miRNA signature comprised of up-regulated miR-1290 and miR-210 and down-regulated miR-29b and miR-32 was identified using RT-qPCR across five epithelial cancer cell lines (SW480, SW620, HT-29, A549 and MDA-MB-231). Experimental modulation of these miRNAs altered expression of their known target mRNAs involved in cell adhesion, proliferation and invasion, in colon cancer cell lines. Furthermore, ITGA5 was identified as a novel putative target of miR-32 that may facilitate cancer cell interactions with the ECM. We propose that culture of cancer cell lines in Matrigel more accurately recapitulates miRNA expression and function in cancer than culture on plastic and thus is a valuable approach to the in vitro study of miRNAs.

Regulation of epidermal growth factor receptor signaling in human cancer cells by microRNA-7

The epidermal growth factor receptor (EGFR) is frequently overexpressed in cancer and is an important therapeutic target. Aberrant expression and function of microRNAs have been associated with tumorigenesis. Bioinformatic predictions suggest that the human EGFR mRNA 3'-untranslated region contains three microRNA-7 (miR-7) target sites, which are not conserved across mammals. We found that miR-7 down-regulates EGFR mRNA and protein expression in cancer cell lines (lung, breast, and glioblastoma) via two of the three sites, inducing cell cycle arrest and cell death. Because miR-7 was shown to decrease EGFR mRNA expression, we used microarray analysis to identify additional mRNA targets of miR-7. These included Raf1 and multiple other genes involved in EGFR signaling and tumorigenesis. Furthermore, miR-7 attenuated activation of protein kinase B (Akt) and extracellular signal-regulated kinase 1/2, two critical effectors of EGFR signaling, in different cancer cell lines. These data establish an important role for miR-7 in controlling mRNA expression and indicate that miR-7 has the ability to coordinately regulate EGFR signaling in multiple human cancer cell types.

Effects of isoflurane, pentobarbital, and urethane on apoptosis and apoptotic signal transduction in rat kidney

BACKGROUND

Renal cell apoptosis contributes significantly to the pathogenesis of acute renal failure. Anesthetic agents have been shown to modulate apoptotic signal transduction in various tissues. We examined the effects of 6 h of different general anesthetic techniques on renal cell apoptosis in rat kidneys.

METHODS

Twenty-one male Sprague-Dawley rats were randomly allocated into four groups: (i) control, non-anesthetized rats (n= 3) and rats anesthetized with (ii) inhaled isoflurane (n= 6), (iii) intraperitoneal pentobarbital (n= 6), and (iv) intraperitoneal urethane (n= 6). Animals were sacrificed 6 h after the induction of anesthesia.

RESULTS

Apoptosis was assessed by terminal deoxynucleotidyl transferase-fluorescein end-labeling analysis. RNA was extracted from the left kidney to probe cDNA microarrays. Gene expression was measured as a percentage of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and subsequently confirmed using reverse transcriptase-polymerase chain reaction (RT-PCR). Compared with the control (no anesthesia), urethane significantly (P < 0.001) induced apoptosis in both the renal cortex and medulla. Isoflurane significantly (P < 0.001) inhibited apoptosis in the medulla. Microarray analysis revealed that urethane up-regulated more (74) genes than pentobarbital (16) and isoflurane (10). Isoflurane down-regulated more genes (85) than pentobarbital (74) and urethane (12). These anesthetic-induced modulations were significant (P < 0.05) for 60 isoflurane-, 30 pentobarbital- and 4 urethane-modulated genes.

CONCLUSION

Our results suggest that general anesthetic drugs have an effect on renal cell apoptosis and apoptotic signal transduction, and thus may potentially affect the risk of subsequent acute renal failure.

Influence of an advance directive on the initiation of life support technology in critically ill cancer patients

OBJECTIVE

To determine whether the presence of an advance directive at admission to an intensive care unit (ICU) influenced the decision to initiate life support therapy in critically ill cancer patients.

DESIGN

Matched-pairs case-control design.

SETTING

The University of Texas M. D. Anderson Cancer Center ICU.

PATIENTS

Of 872 patients treated in the ICU from 1994 to 1996, 236 (27%) were identified as having advance directives. One hundred thirty five patients who had advance directives were successfully matched to 135 patients who did not on the basis of type of malignancy, reason for admission to ICU, severity of illness, and age. These pairs comprised the study group.

INTERVENTIONS

Life-supporting interventions were compared between the matched groups using the McNemar and Wilcoxon matched-pairs signed ranks tests.

MEASUREMENTS AND MAIN RESULTS

No significant difference was found in the frequency with which the following interventions were applied in patients with and without advance directives (respectively): mechanical ventilation, 44% vs. 42%; inotropic support, 31% vs. 31%; pulmonary artery catheterization, 11% vs. 12%; cardiopulmonary resuscitation, 7% vs. 12%; and renal dialysis, 3% vs. 7%. There were also no differences in ICU (75% vs. 73%, respectively) or hospital (56% vs. 59%, respectively) survival. More patients with advance directives than those without had do-not-resuscitate orders within the first 72 hrs (19% vs. 11%, p =.046) and patients with advance directives had shorter ICU durations and lower ICU charges than patients without advance directives.

CONCLUSIONS

After controlling for type of malignancy, reason for admission to the ICU, severity of illness, and age, the decision to initiate life-supporting interventions did not differ significantly among patients with and without advance directives. The presence of an advance directive, however, may have helped guide decisions earlier regarding duration of therapy and resuscitation status.

Characteristics of cardiac arrest in cancer patients as a predictor of survival after cardiopulmonary resuscitation

BACKGROUND

Despite advances in cardiopulmonary resuscitation and the education of its providers, survival remains dismal for cancer patients suffering in-hospital cardiac arrest. In an effort to determine if characteristics of cardiac arrest would represent a useful parameter for prognostication and recommendations regarding the suitability of ongoing resuscitation for various groups, this review was undertaken for patients who experienced in-hospital cardiac arrest.

METHODS

A retrospective study of data gathered between January 1993 and December 1997 was undertaken in a 518-bed comprehensive cancer center. The records of 243 inpatients who experienced cardiac arrest and received cardiopulmonary resuscitation were reviewed, and their course observed until hospital discharge or death.

RESULTS

Sixteen of 73 patients (22%) who had sudden, unanticipated cardiac arrests survived to be discharged from the hospital; however, none (0 of 171) of the patients who experienced an anticipated cardiac arrest survived (P < 0.001). Logistic regression analysis revealed that anticipated cardiac arrest associated with metabolic derangement was an independent predictor of hospital mortality.

CONCLUSIONS

Patients experiencing an anticipated cardiac arrest, the course of which could not be interrupted through aggressive management in an intensive care unit, have an extremely poor prognosis. Ongoing resuscitative measures in these patients need not be routinely provided. The authors suggest an algorithm for resuscitation that evaluates the characteristics of the arrest as a prognostic factor. This algorithm should be implemented once progressive deterioration spirals toward cardiac arrest that cannot be prevented. Such an approach should avoid painful and costly interventions that are futile with the present techniques of cardiopulmonary resuscitation.

An investigation of prospective memory in children with ADHD

Prospective memory, defined as the ability to follow through on intended behavior, is believed to be subserved by a number of neuroanatomical substrates, but particularly dependent, at least in part, on the frontal lobes. Children with Attention-Deficit Hyperactivity Disorder (ADHD) traditionally have difficulty on tasks dependent on frontal lobe structures. The present study attempted to determine whether children with ADHD are impaired in prospective memory function. Two studies are described that use a new measure of time-based prospective memory, the CyberCruiser (Kerns, 2000), to compare children with ADHD to a control group consisting of participants who were matched in respect to age, gender, and IQ. The results document prospective memory deficits in ADHD. Prospective memory performance correlated significantly with clinical measures of ADHD as assessed by the Conners' Parent Rating Scale (Conners, 1990) Hyperactivity Index, but was unrelated to intellectual ability. Though psychometric measures of attention correlated with prospective memory performance, they did not account for the differences in prospective memory that were observed between the ADHD and control groups.

End-of-life decisions in cancer care

End-of-life decisions in critically ill patients with cancer are often complex and fraught with emotion. End-of-life care involves a multidisciplinary approach that takes into account the patient and family's desires and the goals of therapy. Decisions regarding the use of life-support technology at the end of life encompass an outcomes and goal-oriented approach. Ethical, medical, legal, and economic issues should be considered in the assessment of life-support technologies and directives for their appropriate use in the ICU.

What is the role of stimulant laxatives in the management of childhood constipation and soiling?

BACKGROUND

Constipation is extremely common in childhood and may lead to overflow soiling/encopresis. Standard treatment of the more severe case is to empty the bowels of impacted faeces by the use of oral or rectal laxatives and then maintain regular bowel movements by the continuation of osmotic and stimulant laxatives.

OBJECTIVES

The objective of the review was to determine the effect of stimulant laxative treatment in children with chronic constipation who may also suffer from soiling / encopresis.

SEARCH STRATEGY

The Cochrane database of randomised controlled trials was searched. Additional citations were sought by hand searching of paediatric journals and from contact with known professionals in the field.

SELECTION CRITERIA

All identified randomised controlled trials (RCTs) which compare the administering of stimulant laxatives to children with either placebo or alternative treatment.

DATA COLLECTION AND ANALYSIS

No trials were found that met the selection criteria.

MAIN RESULTS

No trials were found that adequately met the selection criteria.

REVIEWER'S CONCLUSIONS

The need exists to establish a secure footing for treatment decisions and adequately sized trials are required to provide comparative data on commonly used drugs.

Identifying risk factors for imminent death in cancer patients with acute dyspnea

A substantial proportion of cancer patients presenting to an emergency center (EC) or clinic with acute dyspnea survives fewer than 2 weeks. If these patients could be identified at the time of admission, physicians and patients would have additional information on which to base decisions to continue therapy to extend life or to refocus treatment efforts on palliation and/or hospice care alone. The purpose of this study was to identify risk factors for imminent death (survival </= 2 weeks) and short-term survival (1, 3, or 6 months) in cancer patients presenting to an EC with acute dyspnea and to combine these factors into a model to help clinicians identify patients with short life expectancies. A random sample of 122 patients presenting to an EC with acute dyspnea was selected for a retrospective analysis. Data that were available to physicians during the initial EC visit included patient histories, triage and discharge vital signs, chest radiographs, and laboratory results. These variables were used in univariate and logistic regression models to develop predictive models for imminent death and short-term survival. Variables and interactions meeting a univariate criterion of P < 0.10 were included in stepwise regression by using forward and backward stepping. Models were compared with the use of Hosmer-Lemeshow statistics and receiver operating characteristics curves. Underlying cancers were 30% breast, 37% lung, and 34% other cancers. Triage respiration greater than 28/min., triage pulse greater than or equal to 110 bpm, uncontrolled progressive disease, and history of metastasis were found to be statistically significant predictors (alpha </= 0.05) of imminent death. Patients with uncontrolled progressive disease had a relative risk of imminent death of 21.93. Relative risks for triage respiration, pulse, and metastases were 12.72, 4.92, and 3.85, respectively. Cancer diagnosis was not predictive of imminent death but was predictive when longer time periods were modeled. It may be possible to identify patients whose death is imminent from a group of cancer patients with acute dyspnea. Some factors that predict imminent death (triage pulse and respiration) differ from those (cancer diagnosis) that predict short-term survival. Extent of disease/response to treatment is common to all models. These factors need further examination and validation. If these findings are confirmed, this quantified information can help physicians in making difficult end-of-life decisions.

Advance directives in critically ill cancer patients

Although advance directives have been used since the 1970s, the discussion of these documents has become more common since the enactment of the Patient Self-Determination Act in 1991. This study evaluated the frequency of advance directives in critically ill patients at a tertiary cancer center and found that cancer patients had a relatively low completion rate of advance directives (27%). The finding that advance directives were more common among Caucasians than other ethnic groups signifies the importance of considering cultural differences when addressing end-of-life issues with patients. The documents also were found more often in older patients with serious diseases. The relationship between hospital mortality and advance directives is complex. The most seriously ill patients and patients with leukemia had the highest mortality and the highest rate of advance directives. Further research on the interactions among mortality, advance directives, and severity of illness is needed. This research contributes to the body of knowledge available on advance directives and particularly sheds light on advance directives in critical ill cancer patients.

Prognostic indicators for blood and marrow transplant patients admitted to an intensive care unit

Although hematopoietic stem cell transplantation (HSCT) can be curative in patients with certain malignancies, survival is poor if the recipient becomes critically ill. This prospective study examined the outcomes of 115 consecutive HSCT patients admitted to the medical intensive care unit (MICU) of a tertiary cancer center and identified variables associated with survival. The need for endotracheal intubation and mechanical ventilation ("intubation") had a profound adverse effect on survival. Overall, 9 of 48 (18.8%) intubated patients survived compared with a survival rate of 44 of 67 (65.7%) among patients not intubated (p < 0.001). This pattern persisted for nearly all patient subgroups. Among intubated patients, those receiving peripheral blood stem cell transplant (PBSCT) had significantly better survival than bone marrow transplant (BMT) patients (8 of 26, 31% versus 1 of 22, 4%; p = 0.028). Multiple logistic regression analyses indicated that the probability a patient admitted to the MICU survived decreased significantly if the patient was intubated, had an allogeneic rather than autologous transplant, had an infection or gastrointestinal bleeding, and also decreased with higher respiratory rate, higher heart rate, longer time from transplant to MICU admission or higher bilirubin. These results may be of value in deciding which critically ill patients will benefit from intubation following major complications after HSCT transplantation.

Nitric oxide synthase and arginase in cells isolated from the rat gastric mucosa

Nitric oxide (NO) synthase activity, which converts arginine to citrulline and NO, is present in homogenates of rat gastric mucosal cells. The aims of this study were to identify the form of NO synthase expressed in gastric cells isolated from fed rats, and to investigate the metabolism of arginine by suspensions of intact mucosal cells. Antibodies directed against the neuronal form of NO synthase recognised a protein of 160 kDa on immunoblots of extracts of gastric cells, and stained isolated cells of approx. 8 microm in diameter. NO synthase was enriched in a cell fraction which banded at high-density in a Percoll gradient, and was inhibited (IC50) by N(G)-nitro-L-arginine (0.8 microM), N(G)-monomethyl-L-arginine (12.6 microM), L-canavanine (147 microM), trifluoperazine (140 microM) and by phosphorylation involving protein kinase C. Intact gastric cells converted exogenous arginine to ornithine and citrulline. Arginase was present in the cells, and was predominantly responsible for arginine metabolism because formation of ornithine and citrulline was reduced by the arginase inhibitors, N(G)-hydroxy-L-arginine and L-ornithine, but not by NO synthase inhibitors such as N(G)-nitro-L-arginine. In conclusion, NO synthase that resembles the neuronal isoform is present in gastric mucosal cells, but a pathway involving arginase seems to be largely responsible for citrulline formation from exogenous arginine in intact mucosal cells.

Dyspnea in cancer patients. Etiology, resource utilization, and survival-implications in a managed care world

BACKGROUND

Dyspnea is the fourth most common symptom of patients who present to the emergency department (ED) at The University of Texas M. D. Anderson Cancer Center and may, in some patients with advanced cancer, represent a clinical marker for the terminal phase of their disease. This retrospective study describes the clinical characteristics of these patients, the resource utilization associated with the management of dyspnea, and the survival of patients with this symptom.

METHODS

The authors randomly selected 122 of 1068 patients presenting with dyspnea for a retrospective analysis. The median age of the patients was 58 years (range, 23-90 years) and 53% were female. Underlying malignancies were breast cancer (30%), lung cancer (37%), and other cancers (34%). Approximately 94% of the patients had received prior cancer treatment and the majority (69%) had uncontrolled, progressive disease.

RESULTS

The most common treatments administered in the ED were oxygen (31%), beta-2 agonists (14%), antibiotics (12%), and narcotics (11%). Approximately 60% of patients were admitted to the hospital from the ED for further treatment of dyspnea and the underlying malignancy, and the median length of stay was 9 days. The median overall survival after the ED visit for dyspnea was 12 weeks. Specific diagnoses were associated with different median survival rates: lung cancer patients: 4 weeks; breast cancer patients: 22 weeks (P = 0.0073, vs. lung cancer); and other cancer diagnoses: 27 weeks (P = 0.0027, vs. lung cancer).

CONCLUSIONS

Lung cancer patients presenting to the ED with dyspnea have much shorter survival than patients with other malignancies. For some patients, the presence of dyspnea requiring emergency treatment may indicate a phase in their illness in which resources should be shifted from acute intervention with hospitalization to palliative and supportive care measures.

Dyspnea in cancer patients. Etiology, resource utilization, and survival-implications in a managed care world

BACKGROUND

Dyspnea is the fourth most common symptom of patients who present to the emergency department (ED) at The University of Texas M. D. Anderson Cancer Center and may, in some patients with advanced cancer, represent a clinical marker for the terminal phase of their disease. This retrospective study describes the clinical characteristics of these patients, the resource utilization associated with the management of dyspnea, and the survival of patients with this symptom.

METHODS

The authors randomly selected 122 of 1068 patients presenting with dyspnea for a retrospective analysis. The median age of the patients was 58 years (range, 23-90 years) and 53% were female. Underlying malignancies were breast cancer (30%), lung cancer (37%), and other cancers (34%). Approximately 94% of the patients had received prior cancer treatment and the majority (69%) had uncontrolled, progressive disease.

RESULTS

The most common treatments administered in the ED were oxygen (31%), beta-2 agonists (14%), antibiotics (12%), and narcotics (11%). Approximately 60% of patients were admitted to the hospital from the ED for further treatment of dyspnea and the underlying malignancy, and the median length of stay was 9 days. The median overall survival after the ED visit for dyspnea was 12 weeks. Specific diagnoses were associated with different median survival rates: lung cancer patients: 4 weeks; breast cancer patients: 22 weeks (P = 0.0073, vs. lung cancer); and other cancer diagnoses: 27 weeks (P = 0.0027, vs. lung cancer).

CONCLUSIONS

Lung cancer patients presenting to the ED with dyspnea have much shorter survival than patients with other malignancies. For some patients, the presence of dyspnea requiring emergency treatment may indicate a phase in their illness in which resources should be shifted from acute intervention with hospitalization to palliative and supportive care measures.

Localization of constitutive isoforms of nitric oxide synthase in the gastric glandular mucosa of the rat

Nitric oxide has been implicated in the regulation of blood flow, mucosal integrity and mucus secretion in the gastric mucosa. An antiserum directed against the C-terminal hexadecapeptide of rat brain nitric oxide synthase (NOS) and monoclonal antibodies to the neuronal and endothelial forms of NOS were used to establish the location of isoforms of NOS in rat gastric glandular mucosa. Antibodies to the neuronal form of NOS reacted with a band of 160 kDa on immunoblots of brain and gastric mucosa, and the addition of the hexadecapeptide inhibited recognition by the antipeptide antiserum. The antibody to endothelial NOS detected a band of 140 kDa on protein blots of samples of intestinal mesentery and gastric mucosa. Immunohistochemistry using these antibodies demonstrated that material related to neuronal NOS was present in surface cells of the gastric mucosa, and showed a similar localization to intense NADPH diaphorase activity. The antibody to endothelial NOS did not stain the surface of the gastric mucosa but recognized blood vessels in the lower region of the gastric glands and in the sub-mucosa. This study suggests that nitric oxide might act both as an intra- and inter-cellular messenger to regulate mucus release, and that the NOS present in surface cells is related more closely to the neuronal than to the endothelial isoform.

Anatomic patterns of Fos immunostaining in rat brain following systemic endotoxin administration

To identify brain neurons that participate in the acute phase response, rat brains were examined immunocytochemically for Fos protein following the intravenous administration of bacterial endotoxin (lipopolysaccharide, LPS). Two to three hours after the injection of LPS, 150 micrograms/kg body weight, to adult male Long-Evans rats, a consistent anatomic pattern of Fos immunostained cell nuclei is seen. In the brain stem, prominant Fos immunostaining is induced in tyrosine hydroxylase immunoreactive neurons of the caudal ventral-lateral medulla (the A1 cell group), in both tyrosine hydroxylase positive and negative neurons of nu. tractus solitarius, in the parabrachial nu., and in a few neurons of the locus ceruleus. In the hypothalamus, endotoxin induces Fos expression in magnocellular neurons of the paraventricular and supraoptic nuclei and internuclear cell groups. A higher percentage of oxytocin-immunoreactive cells is double labeled for Fos nuclear immunostaining than vasopressin-immunoreactive cells. A minority of somatostatin immunoreactive periventricular hypothalamic neurons are Fos positive. Other hypothalamic nuclei that contain endotoxin-induced Fos nuclear immunostaining include the parvocellular neurons of the paraventricular nu., the dorsomedial and arcuate nuclei, the lateral hypothalamus, the dorsal hypothalamic area (zona incerta), and the median nucleus of the preoptic area. LPS induces numerous Fos-positive neurons in regions known to respond to a variety of stressful stimuli; these regions include the preoptic area, bed nucleus of the stria terminalis, lateral septum, and the central and medial nuclei of the amygdala. Moreover, Fos nuclear immunostaining is seen in neurons of circumventricular organs: the organum vasculosum of the lamina terminalis, the subfornical organ, and the area postrema. The maximum intensity of Fos nuclear immunostaining occurs 2-3 h after endotoxin administration and declines thereafter. It is attenuated by pretreatment with indomethacin, 25 mg/kg body weight Sc, or dexamethasone, 1 mg/kg IP. These observations are consistent with the participation of a variety of brain neuronal systems in the acute phase response and elucidate the functional neuroanatomy of that response at the cellular level.

An experimental model of leptomeningeal metastases employing rat mammary carcinoma cells

Five percent of patients dying with breast cancer have leptomeningeal metastases (LM) but current therapy is of only marginal benefit. Therefore, an experimental model of LM from breast cancer was developed to facilitate the development of novel therapies. Cell suspensions of 13762 MAT BIII rat mammary carcinoma cells are injected into the cisterna magna of adult, female Fischer 344 rats under general anesthesia. 10-12 days after the injection of 2 x 10(5) viable cells, animals develop neurologic signs, including ataxia, paralysis and spontaneous rotation. Histologically, tumor cells can be seen in the subarachnoid space over the surface of the brain and spinal cord and within the ventricles. Tumor cells do not invade the brain parenchyma. Collections of tumor cells are extensively infiltrated by macrophages and CD8-positive (suppressor/cytotoxic) T cells, but by few CD4-positive (helper) T cells. MAT BIII cells therefore provide a model of LM from breast cancer with a reproducible clinical course and histologic features. The tumor elicits a cellular immune response and can be useful in exploring biologic therapies for leptomeningeal metastases.

Stimulation by carbachol of mucus gel thickness in rat stomach involves nitric oxide

Instillation of carbachol (150 micrograms/kg) into the gastric lumen in vivo increased the thickness of the mucus gel layer. Intravenous administration of the inhibitor of nitric oxide (NO) synthase, NG-nitro-L- arginine methyl ester (L-NAME, 0.4-5 mg/kg) dose-dependently reduced the stimulation by carbachol, the half-maximal inhibitory dose being 0.57 mg/kg. This effect of L-NAME was abolished by administration of L-arginine but not by D-arginine (100 mg/kg i.v.). By contrast L-NAME (5 mg/kg) did not reduce the stimulatory effect of intraluminal 16,16-dimethyl prostaglandin E2 (50 micrograms/kg) on mucus gel thickness. These results implicate NO in the cholinergic activation of gastric mucus secretion.

Posturally induced vasoconstriction in diabetes mellitus

In healthy subjects, standing elicits a reduction in blood flow to the skin of the foot. In adults with insulin dependent diabetes this posturally induced response is deficient, resulting in capillary hypertension when the foot is in the dependent position (that is, below heart level). Such functional abnormalities of the microcirculation in diabetes may precede any evidence of clinically detectable microangiopathy. This study investigates the posturally induced change in blood flow to the skin of the foot in prepubertal and postpubertal patients with insulin dependent diabetes. Laser Doppler fluximetry was used to assess the postural change in blood flow at the pulp of the great toe. Postural vasoconstriction (dependent flux value/supine flux value x 100) was greater after puberty in normal subjects (median (range) 60.4 (7.0-164.9)% prepubertal v 20.5 (5.9-101.0)% postpubertal). Prepubertal children with diabetes did not differ from their healthy peers (69.8 (7.2-192.7)% with diabetes v 60.4 (7.0-164.9)% controls); however postpubertal children with diabetes had a significantly impaired postural vasoconstriction (40.6 (7.9-140.2)% with diabetes v 20.5 (5.9-101.7)% controls). Abnormalities in the normal reduction of blood flow on standing occurred in young postpubertal children with diabetes, most of whom were free of complications.

Prescribed versus unrestricted carbohydrate diets in children with type 1 diabetes

The diets of 53 children over 8 years of age with diabetes mellitus were examined by 24 h recall. Thirty-seven had been on prescribed carbohydrate diets while 16 had been on an unrestricted carbohydrate diet since diagnosis. The mean intakes of energy (prescribed 9.1 MJ, unrestricted 9.0 MJ, p = 0.66), carbohydrate (prescribed 259 g, unrestricted 251 g, p = 0.64), fat (prescribed 99.8 g, unrestricted 98.2 g, p = 0.84) and fibre (prescribed 29.2 g, unrestricted 31.0 g, p = 0.42) were not significantly different between the two groups. Both groups showed similar distribution of carbohydrate through the day and considerable day to day variation in their carbohydrate intake (coefficient of variation, prescribed 14.5%, unrestricted 14.1%, p = 0.87). Those on prescribed diet had a mean carbohydrate intake which exceeded their prescription by 36%. Both groups had above average fibre intake suggesting that qualitative advice was being followed. There were no significant differences between the two groups in metabolic control (HbA1 prescribed 12.4%, unrestricted 11.9%, p = 0.23), body mass index (prescribed 19.8 kg m-2, unrestricted 20.4 kg m-2) or insulin dosage (prescribed 1 unit kg-1 day-1, unrestricted 0.9 units kg-1 day-1). This study has shown no differences between prescribed and unrestricted carbohydrate diets. Qualitative, rather than quantitative advice may be more appropriate in the management of Type 1 diabetic children.

Hyperthermia induces c-fos expression in the preoptic area

To identify thermosensitive areas of brain, we exposed rats to warm or cool environments and used the expression of the protein Fos as a marker of neuronal activity. In hyperthermic, heat-exposed rats, the median preoptic nucleus, and the medial and lateral preoptic areas had significantly more Fos immunoreactive neurons than control or cold-exposed animals. These observations add to the physiologic evidence that neurons of the preoptic area participate in thermoregulation and provide a means to identify the neurotransmitter systems involved.

Intussusception in preterm infants

Two cases of intussusception in infants born at 26 and 30 weeks' gestation are described. The two infants presented in the neonatal period with abdominal distension, intolerance of feeds, and rectal bleeding. An initial diagnosis of necrotising enterocolitis was made and the infants were treated medically. This led to a delay in the diagnosis of the intussusception. Published work on neonatal intussusception is reviewed and attention is drawn to the fact that the presenting signs and symptoms can be similar to those of necrotising enterocolitis. A diagnosis of intussusception should therefore be considered in any preterm infant with suspected necrotising enterocolitis.

Impaired microvascular hyperaemic response in children with diabetes mellitus

Clinically detectable microvascular complications of diabetes are uncommon in children with diabetes especially in the prepubertal group. It is unclear whether subtle functional abnormalities of the microcirculation occur in children without evidence of clinical microangiopathy and in particular whether abnormalities can be demonstrated in children before puberty. The maximum hyperaemic response to direct local heating (44 degrees C) of the foot skin was measured by laser Doppler fluximetry in 50 diabetic and 50 non-diabetic children. An impaired hyperaemic response occurred in the diabetic children compared with control children (diabetic 1.25 (95% CI 1.13-1.37) V; control 1.74 (1.60-1.88) V; p less than 0.001) and was significantly related to duration of diabetes but not to long-term blood glucose control. The impaired response was also present in prepubertal diabetic children (diabetic 1.37 (1.16-1.58) V; control 1.89 (1.67-2.12) V; p less than 0.001). Systolic and diastolic blood pressure were significantly raised in the prepubertal diabetic children. These data suggest that a functional abnormality of the microcirculation occurs in children with diabetes in the absence of clinically detectable microangiopathy, and even before puberty.

Dried blood spot glucose measurement in hyperinsulinaemic hypoglycaemia

A retrospective analysis of dried blood spot glucose profiles found them to provide useful information about the progress of a child with hyperinsulinism due to nesidiodysplasia. The potential for their use in the management of such cases is discussed.

A prospective trial comparing a silicone elastomer intravenous cannula (Visis) with a polytetrafluoroethylene cannula (Cathlon)

Post-infusion phlebitis remains one of the most frequent causes of hospital morbidity with an incidence varying between 13 and 39 per cent (1-4). A recent study indicated that a silicone elastomer cannula (Visis) had desirable properties (5). We have carried out a prospective trial comparing the value of such a cannula with a Teflon cannula (Cathlon) already in routine use.