The role of different strain backgrounds in bacterial endotoxin-mediated sensitization to neonatal hypoxic-ischemic brain damage

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Strain background plays a role in the response to hypoxia–ischemia.

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LPS sensitizes the immature brain to hypoxia–ischemia across several mouse strains.

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Vehicle injection may induce immune response and sensitization to hypoxia–ischemia.

Genetic background is known to influence the outcome in mouse models of human disease, and previous experimental studies have shown strain variability in the neonatal mouse model of hypoxia–ischemia. To further map out this variability, we compared five commonly used mouse strains: C57BL/6, 129SVJ, BALB/c, CD1 and FVB in a pure hypoxic–ischemic setup and following pre-sensitization with lipopolysaccharide (LPS).

Postnatal day 7 pups were subjected to unilateral carotid artery occlusion followed by continuous 30 min 8% oxygen exposure at 36 °C. Twelve hours prior, a third of the pups received a single intraperitoneal LPS (0.6 μg/g) or a saline (vehicle) administration, respectively; a further third underwent hypoxia–ischemia alone without preceding injection. Both C57BL/6 and 129SVJ strains showed minimal response to 30 min hypoxia–ischemia alone, BALB/c demonstrated a moderate response, and both CD1 and FVB revealed the highest brain damage. LPS pre-sensitization led to substantial increase in overall brain infarction, microglial and astrocyte response and cell death in four of the five strains, with exception of BALB/c that only showed a significant effect with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Saline administration prior to hypoxia–ischemia resulted in an increase in inflammatory-associated markers, particularly in the astroglial activation of C57BL/6 mice, and in combined microglial activation and neuronal cell loss in FVB mice. Finally, two of the four strongly affected strains – C57BL/6 and CD1 – revealed pronounced contralateral astrogliosis with a neuroanatomical localization similar to that observed on the occluded hemisphere.

Overall, the current findings demonstrate strain differences in response to hypoxia–ischemia alone, to stress associated with vehicle injection, and to LPS-mediated pre-sensitization, which partially explains the high variability seen in the neonatal mouse models of hypoxia–ischemia. These results can be useful in future studies of fetal/neonatal response to inflammation and reduced oxygen–blood supply.

The Role of Choledochoscopy

Background. Identifying and surgically removing bile duct calculi is challenging and critical in order to provide good patient outcomes. The history of this surgical pursuit since the introduction of anesthesia is both enlightening and fascinating. Methods. A systematic review of the literature was conducted to identify the techniques and technology used to remove bile duct calculi. Results. All bile duct surgical exploration advances have involved creation of tools to look within the bile duct and extract stones. The Hopkin’s rod lens system was a major breakthrough in light and image transmission. However, flexible endoscope technology added the ability to maneuver better within the bile duct as well as apply the technology via laparoscopy enabling laparoscopic bile duct exploration. Conclusion. Digital, image enhanced, distal tipped chip flexible endoscopes have significantly improved the surgeons’ ability to see within the bile duct, improving the efficiency and ease of stone visualization and removal from both the most proximal and distal ends of the bile duct.

"I'm 100% for it! I'm a convert!": women's experiences of a yoga programme during treatment for gynaecological cancer; an interpretative phenomenological analysis

OBJECTIVES

To explore patients' experiences of taking part in a yoga intervention while undergoing treatment for gynaecological cancer.

DESIGN

Sixteen women (age range 31-79 years; mean age 60) participated in focus groups based on a semi-structured question schedule. Resulting discussions were audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis (IPA).

SETTING

Royal Derby Hospital, UK.

INTERVENTIONS

Patients took part in a 10-week course of Hatha yoga, where they participated in a one hour long class per week.

RESULTS

Three themes emerged from the data: applying breathing techniques, engaging in the physicality of yoga and finding a community. The first theme was particularly important to the patients as they noted the breadth and applicability of the techniques in their day-to-day lives. The latter two themes reflect physical and social perspectives, which are established topics in the cancer and yoga literature and are contextualised here within the women's experiences of cancer treatment.

CONCLUSIONS

The women's perceptions of the programme were generally positive, providing a previously unseen view of the patient experience of participating in a yoga intervention. The difference between the women's prior expectations and lived experiences is discussed.

Dental Therapists

Dental therapists are members of the dental team in many countries, where they perform a limited number of irreversible restorative procedures. In the United States, they practice only in Alaska and Minnesota, though other states are considering adding them in an effort to improve access to care. While critics of this workforce model cite concern for patient safety, proponents argue that dental therapists provide treatment that is as technically competent as that provided by dentists. Though nearly 2 dozen studies from industrialized countries address this subject, this article systematically reviews all 23 of them. Of these reports, all but 2 conclude that dental therapists perform at an acceptable level. Every study that directly compared the work of dental therapists with that of dentists found that they performed at least as well. Regardless of whether dental therapists would be the most effective intervention for improving access to oral health care in the United States, the evidence clearly suggests dental therapists are clinically competent to safely perform the limited set of procedures that falls within their scope of practice.

Association between 25-OH vitamin D and insulin is independent of lipoatrophy in HIV

OBJECTIVE

Vitamin D deficiency (VDD) is prevalent in HIV, and following antiretroviral therapy (ART), increased rates of lipoatrophy and metabolic abnormalities are described. We investigated the relationships between 25-hydroxyvitamin D [25(OH)D] and other metabolic parameters in a group of HIV patients with and without lipoatrophy to examine whether lipoatrophy could explain the high prevalence of VDD and metabolic abnormalities.

BACKGROUND

Vitamin D receptors are expressed in adipose tissue implicating vitamin D, through paracrine/autocrine mechanism, in exerting effects on fat metabolism. HIV patients frequently suffer from VDD, and those treated with thymidine analogues frequently suffer from lipoatrophy so we investigated whether lipoatrophy could explain these associations.

DESIGN AND PATIENTS

Cross-sectional study of HIV-infected male patients (n = 107; 39 with lipoatrophy) from the West Australian cohort with measurements of 25(OH)D, adiponectin, insulin, lipids and leg fat as a percentage of mass.

RESULTS

Reduced 25(OH)D levels were common and significantly associated with higher serum insulin in the entire cohort (P = 0·006), but there was no difference in 25(OH)D between untreated and antiretroviral-treated patients with or without lipoatrophy. Treated patients with lipoatrophy were more likely to take thymidine analogue therapy, were older and on therapy longer than treated patients without lipoatrophy. Adiponectin levels did not correlate with 25(OH)D, but lipoatrophic-treated patients had lower levels of adiponectin compared with nonlipoatrophic-treated patients.

CONCLUSIONS

Lower 25(OH)D is associated with higher serum insulin but not lipoatrophy or hypoadiponectinemia in HIV-infected patients. The association between VDD and insulin resistance is likely to be mediated by independent mechanisms.

Growth of Strain SES-3 with Arsenate and Other Diverse Electron Acceptors

The selenate-respiring bacterial strain SES-3 was able to use a variety of inorganic electron acceptors to sustain growth. SES-3 grew with the reduction of arsenate to arsenite, Fe(III) to Fe(II), or thiosulfate to sulfide. It also grew in medium in which elemental sulfur, Mn(IV), nitrite, trimethylamine N-oxide, or fumarate was provided as an electron acceptor. Growth on oxygen was microaerophilic. There was no growth with arsenite or chromate. Washed suspensions of cells grown on selenate or nitrate had a constitutive ability to reduce arsenate but were unable to reduce arsenite. These results suggest that strain SES-3 may occupy a niche as an environmental opportunist by being able to take advantage of a diversity of electron acceptors.

Provider-initiated HIV testing and counselling for TB patients and suspects in Nairobi, Kenya

SETTING

Integrated tuberculosis (TB) and human immunodeficiency virus (HIV) services in a resource-constrained setting.

OBJECTIVE

Pilot provider-initiated HIV testing and counselling (PITC) for TB patients and suspects.

DESIGN

Through partnerships, resources were mobilised to establish and support services. After community sensitisation and staff training, PITC was introduced to TB patients and then to TB suspects from December 2003 to December 2005.

RESULTS

Of 5457 TB suspects who received PITC, 89% underwent HIV testing. Although not statistically significant, TB suspects with TB disease had an HIV prevalence of 61% compared to 63% for those without. Of the 614 suspects who declined HIV testing, 402 (65%) had TB disease. Of 2283 patients referred for cotrimoxazole prophylaxis, 1951 (86%) were enrolled, and of 1727 patients assessed for antiretroviral treatment (ART), 1618 (94%) were eligible and 1441 (83%) started treatment.

CONCLUSIONS

PITC represents a paradigm shift and is feasible and acceptable to TB patients and TB suspects. Clear directives are nevertheless required to change practice. When offered to TB suspects, PITC identifies large numbers of persons requiring HIV care. Community sensitisation, staff training, multitasking and access to HIV care contributed to a high acceptance of HIV testing. Kenya is using this experience to inform national response and advocate wide PITC implementation in settings faced with the TB-HIV epidemic.

Prevalence of vitamin D depletion among subjects seeking advice on osteoporosis: a five-year cross-sectional study with public health implications

We assessed vitamin D nutritional status in unselected consecutive patients seeking advice on osteoporosis. The prevalence of vitamin D depletion ranged from 15-72% depending upon the cut-off levels used for serum 25-hydroxyvitamin D, and the prevalence did not change over the 5 years of the study.

INTRODUCTION

Vitamin D depletion is a significant public health problem and has been studied in different populations using different cut-off levels, but the optimal level is yet to be established.

METHODS

In a cross-sectional study of 2,924 patients seen for osteoporosis advice we determined the prevalence of vitamin D depletion, as assessed by 25-hydroxyvitamin D (25-OHD), using three different cut-off levels stratified by gender, race and the year of the study over 5 years.

RESULTS

Mean age was 68.3 +/- 10.0 years; 90% women and 88% white. Mean 25-OHD level was 24.6 +/- 10 ng/ml and mean PTH was 48.4 +/- 32 pg/ml. The prevalence of vitamin D depletion was 15% with a cut-off level of <15 ng/ml, and rose to 32% and 72% with cut-off levels <20 ng/ml and <30 ng/ml, respectively. The prevalence was higher in men and blacks and remained constant over 5 years, regardless of the cut-off level. The expected inverse relationship between 25-OHD and PTH was observed irrespective of gender or ethnicity.

CONCLUSIONS

The prevalence of vitamin D depletion in patients seeking advice for osteoporosis is high and did not change over the 5 years of the study.

Determinants of influenza vaccination in hard-to-reach urban populations

OBJECTIVE

Influenza vaccination rates among disadvantaged minority and hard-to-reach populations are lower than in other groups. We assessed the barriers to influenza vaccination in disadvantaged urban areas.

METHODS

We conducted a cross-sectional study, using venue-based sampling, collecting data on residents of eight neighborhoods throughout East Harlem and the Bronx, New York City.

RESULTS

Of 760 total respondents, 461 (61.6%) had received influenza vaccination at some point in their life. In multivariable models, having access to routine medical care, receipt of health or social services, having tested positive for HIV, and current interest in receiving influenza vaccination were significantly associated with having received influenza vaccination in the previous year. Of participants surveyed, 79.6% were interested in receiving an influenza vaccination at the time of survey. Among participants who had never previously received influenza vaccination in the past, 73.4% were interested in being vaccinated; factors significantly associated with an interest in being vaccinated were minority race, lower annual income, history of being homeless, being uninsured/underinsured, and not having access to routine medical care.

CONCLUSIONS

Participants who are unconnected to health or social services or government health insurance are less likely to have been vaccinated in the past although these persons are willing to receive vaccine if it were available.

Oxidant regulation of the bivalent cation transporter Nramp1

Nramp1 (murine natural resistance-associated macrophage protein 1 gene)/Slc11a1 (solute carrier family 11 member a1 gene) encodes a bivalent-metal/iron transporter that is expressed within late endosomes/lysosomes of macrophages. A functionally null Nramp1 allele that exhibits impaired bivalent cation transport enables excessive growth of intracellular pathogens. Iron is important for many cellular activities, including defence against pathogens; however, redox-active/free iron can participate in Fenton chemistry that generates reactive oxygen species. Using Raw264.7 cells, non-functional for Nramp1, and stable Nramp1 transfectants, we have examined the effects of impaired bivalent cation transport on macrophage function using glutathione depletion as OS (oxidant stress). Our results demonstrate that OS itself is a signal for increasing Nramp1 transcription and that Nramp1 expression protects against OS. We suggest that OS-mediated protection by Nramp1 function may arise from direct removal of redox-active bivalent cations from a cytosolic pool. We show that OS transcriptional responses are probably mediated by the Sp1 transcription factor.