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Biomedical subjects

N Hunt

Publications and source records attributed to N Hunt.

At least 19 recordsLinked to original sources
PubMed2006

Calorie restriction induces mitochondrial biogenesis and bioenergetic efficiency.

Age-related accumulation of cellular damage and death has been linked to oxidative stress. Calorie restriction (CR) is the most robust, nongenetic intervention that increases lifespan and reduces the rate of aging in a variety of species. Mechanisms responsible for the antiaging effects of CR remain uncertain, but reduction of oxidative stress within mitochondria remains a major focus of research. CR is hypothesized to decrease mitochondrial electron flow and proton leaks to attenuate damage caused by reactive oxygen species. We have focused our research on a related, but different, antiaging mechanism of CR. Specifically, using both in vivo and in vitro analyses, we report that CR reduces oxidative stress at the same time that it stimulates the proliferation of mitochondria through a peroxisome proliferation-activated receptor coactivator 1 alpha signaling pathway. Moreover, mitochondria under CR conditions show less oxygen consumption, reduce membrane potential, and generate less reactive oxygen species than controls, but remarkably they are able to maintain their critical ATP production. In effect, CR can induce a peroxisome proliferation-activated receptor coactivator 1 alpha-dependent increase in mitochondria capable of efficient and balanced bioenergetics to reduce oxidative stress and attenuate age-dependent endogenous oxidative damage.

Caloric Restriction↗
PubMed2006

Falklands War veterans' perceptions of social support and the reconciliation of traumatic memories.

The current paper focused on the role social support plays in the reconciliation of traumatic memories. Four currently serving, male Royal Marines ranging from 40-42 years participated in semi-structured one-to-one interviews that explored perceptions of social support. Using thematic analysis, comradeship was found to be important in terms of maintaining support networks. However, this resource was used to avoid the reconciliation of traumatic memories. Social support from family members was sought when veterans were reassured that relatives would understand their experiences, and could support reconciliation. The importance of positive societal reaction was also emphasized. The paper concludes by highlighting the potential for early life reconciliation of traumatic war memories through the creation of a meaningful personal narrative.

Adaptation, Psychological↗
PubMed2006

Cultured skin fibroblast cells derived from bluetongue virus-inoculated sheep and field-infected cattle are not a source of late and protracted recoverable virus.

A recent hypothesis to explain the recurrence of bluetongue disease after winter seasonal absences of the vector has suggested a role for persistent infection of sheep. This report presents combined independent work from two laboratories investigating the possible recovery of Bluetongue virus (BTV) over a protracted period after infection of both sheep and cattle. Prior to infection with either cell-culture-adapted or non-culture-adapted BTV, sheep were subjected to a preliminary exposure to Culicoides sp. insects, which reportedly facilitates recovery of virus from infected sheep several months post-infection (p.i.). A series of skin biopsies at different intervals p.i. was used to establish skin fibroblast (SF) cultures from which attempts were made to detect virus by isolation and by molecular and immunological methods. Also examined was the effect on virus recovery of additional exposure to Culicoides sp. prior to skin biopsy during the post-inoculation period. A herd of cattle sentinels for surveillance of natural BTV infection in northern Australia was monitored prospectively for seroconversion. Evidence of infection initiated attempted virus recovery by establishing SF cultures. It was found that in both cattle and sheep there was not a protracted period over which BTV could be recovered from SF cultures. The data do not support a general hypothesis that BTV persists in either sheep or cattle.

Animals↗
PubMed2005

Current management of bipolar affective disorder: is it reflective of the BAP guidelines?

In October 2003 the British Association of Psychopharmacology (BAP) published evidence-based guidelines on the management of bipolar disorder. The aim of this study was to assess whether the guidelines could provide the basis for examining clinical decisions and the extent to which practice accords with these guidelines. Case notes of out patients with bipolar disorder were reviewed. Demographic details, and treatment recommendations were determined. The management of affective episodes was evaluated and compared with BAP guidelines. In 84 subjects, 224 affective episodes were identified. Treatment was consistent with BAP guidelines in 72% of episodes. Mania was more likely to be managed in accordance with guidelines than depression or mixed episodes. The use of antidepressant medication was the most likely intervention to deviate from recommendations. Reasons for treatments at odds with the guidelines were identified. Our study demonstrates that clinical practice among a range of psychiatrists broadly reflects the guidelines that have been issued by the British Association of Psychopharmacology (BAP). The BAP guidelines offer a practical and auditable basis for the short- and long-term treatment of bipolar affective disorder.

Adolescent↗
PubMed2005

Nitrogen and phosphorus removal from plant nursery runoff in vegetated and unvegetated subsurface flow wetlands.

Subsurface horizontal flow reed beds are being evaluated for Nitrogen (N) and Phosphorus (P) removal from plant nursery runoff water in New South Wales Australia. The need to include plants (Phragmites australis), the effect of reaction time (3.5 v 7.0 d) and dissolved organic carbon (DOC) on N and P removal in batch fed gravel wetland tubs (55 L) was studied over 19 months. Simulated nursery runoff water containing N (10.1 mg L(-1), 74% as NO3) and P (0.58 mg L(-1), 88% as PO4) and DOC (2-5 mg L(-1)) was used. The planted wetland tubs removed >96% TN and TP over most of the 19-month study period while unplanted tubs were inefficient (<16% N and <45% P removal) and occasionally discharged nutrients. Doubling the reaction time to 7.0 days had no effect on nutrient removal. Plant nutrient uptake accounted for most of the N (76%) and P (86%) removed while roots and rhizomes were the dominant sink (N 58%, P 67%). The addition of methanol (C:N-3:1) to unplanted tubs achieved 81-98% N removal. In Carbon limited low nutrient nursery runoff, plants were essential to a gravel-based wetland to achieve efficient nutrient removal with effluent TN and TP concentrations of <1 mg L(-1) and 0.05 mg L(-1), respectively with a 3.5 day reaction time.

Agriculture↗
PubMed2004

Genetic basis of erythromycin resistance in oral bacteria.

We determined the prevalence of erythromycin-resistant bacteria in the oral cavity and identified mef and erm(B) as the most common resistance determinants. In addition, we demonstrate the genetic linkage, on various Tn1545-like conjugative transposons, between erythromycin and tetracycline resistance in a number of isolates.

Anti-Bacterial Agents↗
PubMed2003

An easy and accurate preoperative method for determining tibial nail lengths.

Estimating the correct nail length for solid tibial nails can be problematic. Most techniques reported in the literature for determining tibial nail length are not accurate. In a retrospective study of 16 patients in our unit, only three had ideal nail sizes. In these patients, as part of phase I of our study, we measured their normal leg's length from knee joint line to ankle joint line. An ideal nail length for each of these patients was estimated from a whole length radiograph of the nailed tibia. Comparing these two data, we found that deducting 20 mm from the leg measurement gave appropriate nail lengths. We also compared this with three other anthropometric measurements; tibial tuberosity to medial malleolus, joint line to medial malleolus and olecranon to head of V metacarpal head distance. The joint line to joint line measurement was the most reliable and showed the best correlation with ideal nail lengths (0.982). In phase II, a prospective study on 15 patients, we used the joint line to joint line measurement to determine nail sizes. A postoperative review of the radiographs showed all the nails to be of adequate length. This strengthened the fact that the joint line to joint line measurement is the most accurate and easy method to determine tibial nail lengths.

Anthropometry↗
PubMed2003

Prevalence of tetracycline resistance genes in oral bacteria.

Tetracycline is a broad-spectrum antibiotic used in humans, animals, and aquaculture; therefore, many bacteria from different ecosystems are exposed to this antibiotic. In order to determine the genetic basis for resistance to tetracycline in bacteria from the oral cavity, saliva and dental plaque samples were obtained from 20 healthy adults who had not taken antibiotics during the previous 3 months. The samples were screened for the presence of bacteria resistant to tetracycline, and the tetracycline resistance genes in these isolates were identified by multiplex PCR and DNA sequencing. Tetracycline-resistant bacteria constituted an average of 11% of the total cultivable oral microflora. A representative 105 tetracycline-resistant isolates from the 20 samples were investigated; most of the isolates carried tetracycline resistance genes encoding a ribosomal protection protein. The most common tet gene identified was tet(M), which was found in 79% of all the isolates. The second most common gene identified was tet(W), which was found in 21% of all the isolates, followed by tet(O) and tet(Q) (10.5 and 9.5% of the isolates, respectively) and then tet(S) (2.8% of the isolates). Tetracycline resistance genes encoding an efflux protein were detected in 4.8% of all the tetracycline-resistant isolates; 2.8% of the isolates had tet(L) and 1% carried tet(A) and tet(K) each. The results have shown that a variety of tetracycline resistance genes are present in the oral microflora of healthy adults. This is the first report of tet(W) in oral bacteria and the first report to show that tet(O), tet(Q), tet(A), and tet(S) can be found in some oral species.

Adult↗
PubMed2003

Novel tetracycline resistance determinant from the oral metagenome.

A major drawback of most studies on how bacteria become resistant to antibiotics is that they concentrate mainly on bacteria that can be cultivated in the laboratory. In the present study, we cloned part of the oral metagenome and isolated a novel tetracycline resistance gene, tet(37), which inactivates tetracycline.

Adult↗
PubMed2001

A preliminary trial of high-dose ursodeoxycholic acid in primary sclerosing cholangitis.

BACKGROUND & AIMS: Ursodeoxycholic acid (UDCA) is used for the treatment of cholestatic liver diseases including primary biliary cirrhosis (PBC) for which it has a positive effect on laboratory values, may delay the development of liver failure and prolong the transplant-free disease period. Standard doses of UDCA (8-15 mg/kg daily) have been shown to be ineffective in the treatment of primary sclerosing cholangitis (PSC). We report on the findings (clinical, biochemical, histological, and cholangiographic) and side effects of a 2-year double-blind placebo-controlled preliminary study of high-dose UDCA in PSC patients. METHODS: Twenty-six patients with PSC were randomized to high-dose (20 mg/kg daily) UDCA or placebo. Cholangiography and liver biopsy were performed at entry and after 2 years. Symptoms, clinical signs, and liver biochemical tests were recorded at 3 monthly intervals. RESULTS: High-dose UDCA did not influence symptoms, but there was a significant improvement in liver biochemistry (serum alkaline phosphatase, P = 0.03; gamma-glutamyl transferase, P = 0.01) and a significant reduction in progression in cholangiographic appearances (P = 0.015) and liver fibrosis as assessed by disease staging (P = 0.05). In the treatment group, a significant increase in total bile acids and saturation with UDCA >70% confirmed patient compliance. No significant side effects were reported. CONCLUSIONS: High-dose UDCA may be of clinical benefit in PSC, but trials with a larger number of participants and of longer duration are required to establish whether the effect of high-dose UDCA on liver biochemistry, histology, and cholangiography in patients with PSC is translated into improved long-term survival.

Adult↗
PubMed2001

Chondral lesions of the knee: A new localization method and correlation with associated pathology.

PURPOSE: We report a new method of describing and recording chondral lesions of the knee at arthroscopy in order to permit a more accurate and meaningful analysis of patterns of articular cartilage damage. TYPE OF STUDY: Case series study. METHODS: Data were collected prospectively at 1,000 consecutive arthroscopies by the senior author and chondral lesions were recorded on anatomic articular maps divided into different functional zones. Ten zones on the femur were determined by tibiofemoral weight-bearing and flexion horizons (namely the 0 degrees, 45 degrees, 90 degrees, and 120 degrees horizons as they pass the anterior meniscosynovial junction). Ten zones were determined on the tibia, principally by meniscal relations, and 6 zones on the patella. This allowed the size, Outerbridge grade, and location to be analyzed in relation to mechanism, chronicity, and associated intra-articular pathologies. The recording methods were tested for interobserver reproducibility in 50 subsequent cases at the same arthroscopy by 2 independent observers. The results were analyzed by a third person, and showed a relatively small interobserver error of 7.2% for size for a set of grade 3 and 4 lesions and only a 3% error for site. The Fisher exact test was used. The data sheets were entered onto a computer spreadsheet database using standard software (Excel; Microsoft, Redmond, WA) to permit analysis of the data. RESULTS: There were 1,553 chondral lesions in 853 patients correlated with associated lesions, including 356 meniscal lesions, 230 ligamentous injuries, 440 synovial lesions, and other pathologies. High degrees of correlation have been found between specific lesions and their opposing surfaces and the progression of these with time. CONCLUSIONS: The problem of precision of localization of articular lesions in the knee has been recently acknowledged by the International Cartilage Research Society (ICRS). However, such recording ought to take into account both function and contact with other structures. This would appear essential in the assessment of prognosis and comparisons between different treatment regimes.

Adolescent↗
PubMed2001

World war II veterans, social support, and veterans' associations.

People use many different coping strategies to deal with their traumatic recollections. Twenty-five British World War II veterans were interviewed regarding the ways they used social support both during the war and in the years afterwards. The findings demonstrate that social support is used in fundamentally different ways. During the war comradeship was particularly important and even fifty years after the war comrades are still a valuable resource for discussing war experiences, and dealing with the emotional content of traumatic recollections. Veterans rely on wives and families to help deal with the more physical and practical elements of coping, but tend not to discuss their traumatic memories with them. The findings show that social support is an important lifelong coping strategy for World War II veterans.

Adaptation, Psychological↗
PubMed2001

The long-term consequences of war: the experience of World War II.

Seven hundred and thirty-one World War II and Korean War veterans completed a questionnaire about their experiences and their current psychological reactions to the war. Nineteen percent scored above the cut-off points for both the General Health Questionnaire and the (war-related) Impact of Event Scale, demonstrating that, even over 50 years after the event, many veterans still experience problems relating to their war experiences. Psychological distress was in part directly related to particular experiences, but intrusion and avoidance both played an important role as mediating variables. Other factors, such as prisoner of war (POW) status, type of service, rank, and illness were also considered. The findings indicate that the effects of a traumatic experience such as war can persist into later life.

Adaptation, Psychological↗
PubMed2001

Recent advances in the design and performance of research assistants.

Every laboratory needs personnel who work 24 hours a day 7 days a week, are efficient, obedient, capable of showing initiative, insightful and affable. Our experience of laboratory workers tells us that there is an immense way to go to achieve these goals. Having tired of the normal, Darwinian approach, a project has been initiated to achieve these ends through genetic technologies.

Humans↗
PubMed2001

Faster introduction of cost-effective packaging films.

The introduction of more cost-effective packaging is restricted by the lack of resources and time that is available for validating new materials. New techniques are being developed to shorten approval times and reduce hold-ups in benefitting from innovative packaging solutions.

Cost-Benefit Analysis↗
PubMed2001

Incidence, natural history and risk factors of deep vein thrombosis in elective knee arthroscopy.

AIMS: to determine the incidence, anatomical distribution and extent of deep vein thrombosis (DVT) in limbs undergoing elective unilateral knee arthroscopy without active prophylaxis, to evaluate its effect on venous function following early diagnosis, and to quantify the impact of risk factors on its incidence. METHODS: 102 consecutive patients undergoing unilateral knee arthroscopy without prophylaxis were studied. A history was obtained with emphasis on the risk factors for thromboembolism, and physical examination and colour duplex were performed prior to and within a week after surgery. Patients who developed calf DVT were given aspirin (150 mg) and compression stockings; those with proximal DVT were admitted for anticoagulation (heparin followed by warfarin). Follow-up (mean 118 [range 84-168] days) entailed weekly physical and duplex examinations during the first month and monthly thereafter. RESULTS: 8 patients developed calf DVT in the operated leg (incidence 7.84% [95% CI: 2.7%-13.2%]); thrombosis was asymptomatic in 4 of those (50%), caused calf tenderness in 4 (50%) and a positive Homan's sign in one (12.5%). DVT occurred in the following veins: peroneal 4 subjects (50%), soleal 4 (50%), gastrocnemial 2 (25%) and tibial 2 (25%). Propagation of a calf DVT to the popliteal vein was identified in 1 patient (12.5%). After a median period of 118 days, total clot lysis was found in 50% of DVTs. with partial thrombus resorption in the rest; reflux in the thrombosed veins was present in 75% of limbs with DVT. 43% of patients had 1 risk factor for DVT and 20% had > or = 2. The incidence of DVT was higher amongst those with two or more risk factors for thromboembolism (p <.05) or those with previous thrombosis alone (p <.005). Symptoms or signs of pulmonary embolism were not documented. CONCLUSIONS: Elective unilateral knee arthroscopy performed without prophylaxis is complicated by ipsilateral calf DVT in 7.8% (95% CI: 2.7%-13.2%) of cases. The risk is higher in the presence of previous thrombosis (relative risk: 8.2) and two or more risk factors for DVT (relative risk: 2.94). Thrombosis may propagate to the proximal veins, despite early diagnosis. 50% of calf clots totally lyse in 4 months, yet reflux develops in at least 75% of limbs with DVT. Further studies to determine optimal prophylaxis are warranted.

Adolescent↗