Biomedical subjects

C Hill

Publications and source records attributed to C Hill.

At least 73 records · Page 4Linked to original sources

PubMed2001

Exploitation of plasmid pMRC01 to direct transfer of mobilizable plasmids into commercial lactococcal starter strains.

Genetic analysis of the 60.2-kb lactococcal plasmid pMRC01 revealed a 19.6-kb region which includes putative genes for conjugal transfer of the plasmid and a sequence resembling an origin of transfer (oriT). This oriT-like sequence was amplified and cloned on a 312-bp segment into pCI372, allowing the resultant plasmid, pRH001, to be mobilized at a frequency of 3.4 x 10(-4) transconjugants/donor cell from an MG1363 (recA mutant) host containing pMRC01. All of the resultant chloramphenicol-resistant transconjugants contained both pRH001 and genetic determinants responsible for bacteriocin production and immunity of pMRC01. This result is expected, given that transconjugants lacking the lacticin 3147 immunity determinants (on pMRC01) would be killed by bacteriocin produced by the donor cells. Indeed, incorporation of proteinase K in the mating mixture resulted in the isolation of transformants, of which 47% were bacteriocin deficient. Using such an approach, the oriT-containing fragment was exploited to mobilize pRH001 alone to a number of lactococcal hosts. These results demonstrate that oriT of pMRC01 has the potential to be used in the development of mobilizable food-grade vectors for the genetic enhancement of lactococcal starter strains, some of which may be difficult to transform.

Bacterial Proteins↗

PubMed2001

Characterization of the groESL operon in Listeria monocytogenes: utilization of two reporter systems (gfp and hly) for evaluating in vivo expression.

The ability of intracellular pathogens to sense and adapt to the hostile environment of the host is an important factor governing virulence. We have sequenced the operon encoding the major heat shock proteins GroES and GroEL in the gram-positive food-borne pathogen Listeria monocytogenes. The operon has a conserved orientation in the order groES groEL. Upstream of groES and in the opposite orientation is a gene encoding a homologue of the Bacillus subtilis protein YdiL, while downstream of groEL is a gene encoding a putative bile hydrolase. We used both reverse transcriptase-PCR (RT-PCR) and transcriptional fusions to the UV-optimized Aequorea victoria green fluorescent protein (GFP(UV)) to analyze expression of groESL under various environmental stress conditions, including heat shock, ethanol stress, and acid shock, and during infection of J774 mouse macrophage cells. Strains harboring GFP(UV) transcriptional fusions to the promoter region of groESL demonstrated a significant increase in fluorescence following heat shock that was detected by both fluorimetry and fluorescence microscopy. Using both RT-PCR and GFP technology we detected expression of groESL following internalization by J774 cells. Increased intracellular expression of dnaK was also determined using RT-PCR. We have recently described a system which utilizes L. monocytogenes hemolysin as an in vivo reporter of gene expression within the host cell phagosome (C. G. M. Gahan and C. Hill, Mol. Microbiol. 36:498-507, 2000). In this study a strain was constructed in which hemolysin expression was placed under the control of the groESL promoter. In this strain hemolysin expression during infection also confirms transcription from the groESL promoter during J774 and murine infection, albeit at lower levels than the known virulence factor plcA.

Animals↗

PubMed2001

The occurrence of ventilator-associated pneumonia in a community hospital: risk factors and clinical outcomes.

STUDY OBJECTIVES: To prospectively identify the occurrence of ventilator-associated pneumonia (VAP) in a community hospital, and to determine the risk factors for VAP and the influence of VAP on patient outcomes in a nonteaching institution. DESIGN: Prospective cohort study. SETTING: A medical ICU and a surgical ICU in a 500-bed private community nonteaching hospital: Missouri Baptist Hospital. PATIENTS: Between March 1998 and December 1999, all patients receiving mechanical ventilation who were admitted to the ICU setting were prospectively evaluated. INTERVENTION: Prospective patient surveillance and data collection. RESULTS: During a 22-month period, 3,171 patients were admitted to the medical and surgical ICUs. Eight hundred eighty patients (27.8%) received mechanical ventilation. VAP developed in 132 patients (15.0%) receiving mechanical ventilation. Three hundred one patients (34.2%) who received mechanical ventilation died during hospitalization. Logistic regression analysis demonstrated that tracheostomy (adjusted odds ratio [AOR], 6.71; 95% confidence interval [CI], 3.91 to 11.50; p < 0.001), multiple central venous line insertions (AOR, 4.20; 95% CI, 2.72 to 6.48; p < 0.001), reintubation (AOR, 2.88; 95% CI, 1.78 to 4.66; p < 0.001), and the use of antacids (AOR, 2.81; 95% CI, 1.19 to 6.64; p = 0.019) were independently associated with the development of VAP. The hospital mortality of patients with VAP was significantly greater than the mortality of patients without VAP (45.5% vs 32.2%, respectively; p = 0.004). The occurrence of bacteremia, compromised immune system, higher APACHE (acute physiology and chronic health evaluation) II scores, and older age were identified as independent predictors of hospital mortality. CONCLUSIONS: These data suggest that VAP is a common nosocomial infection in the community hospital setting. The risk factors for the development of VAP and risk factors for hospital mortality in a community hospital are similar to those identified from university-affiliated hospitals. These risk factors can potentially be employed to develop local strategies for the prevention of VAP. CLINICAL IMPLICATIONS: ICU clinicians should be aware of the risk factors associated with the development of VAP and the impact of VAP on clinical outcomes. More importantly, they should cooperate in the development of local multidisciplinary strategies aimed at the prevention of VAP and other nosocomial infections.

APACHE↗

PubMed2001

Transforming growth factor-beta2 antibody attenuates fibrosis in the experimental diabetic rat kidney.

Diabetic nephropathy is characterised by an increase in glomerular and tubular fibrosis that compromises kidney function. The transforming growth factor-betas (TGF-betas) have been shown to play a major role in fibrosis and we have shown that TGF-beta2, in particular, increases co-ordinately with fibrogenesis in the diabetic kidney. The aim of this study was to investigate the changes in expression of extracellular matrix molecules in the diabetic kidney, with and without systemic administration of a recombinant human monoclonal antibody to TGF-beta2. Streptozotocin-induced diabetic rats were split into two groups. The first were treated with 5 mg/kg irrelevant control IgG4 (placebo) and the second treated with 5 mg/kg isoform-specific recombinant monoclonal anti-TGF-beta2 IgG4 (termed CAT-152) systemically every second day for 14 days. A further group of six non-diabetic rats was also used as a control. Various biological parameters were measured daily throughout the experimental period, and on termination of the experiment at 14 days Western blotting was performed on kidney cortices for procollagen-I C-propeptide, which is an indicator of the rate of collagen-I synthesis within the kidney. In the placebo-treated diabetic rats, blood glucose, food consumption, urinary albumin excretion (UAE) and kidney weights were all significantly higher than in the non-diabetic group (P<0.05, n=24, by ANOVA). In the anti-TGF-beta2-treated diabetic rats, kidney weights and UAE levels were decreased when compared with those in placebo-treated diabetics. Western blotting for the procollagen-I C-propeptide in kidney cortices showed a significant increase in levels in placebo-treated diabetic rats compared with non-diabetic controls over the 14 day diabetic period, indicating initiation of fibrogenesis. By contrast, in anti-TGF-beta2-treated diabetic rats, levels of the propeptide remained at non-diabetic levels. In summary, a significant suppression of kidney fibrosis was seen in anti-TGF-beta2-treated diabetic rats, compared with placebo-treated diabetic rats. We conclude that systemic delivery of CAT-152, a neutralising anti-TGF-beta2 antibody, during the acute stages of diabetic nephropathy reduces the rate of pathogenic fibrosis in the kidney.

Albuminuria↗

PubMed2001

Role of the glutamate decarboxylase acid resistance system in the survival of Listeria monocytogenes LO28 in low pH foods.

The glutamate decarboxylase (GAD) acid resistance system of the foodborne pathogen Listeria monocytogenes plays a major role in its survival at low pH. It was found that survival of the wild-type strain. LO28, in acidified reconstituted skim milk, diluted to reduce free glutamate levels. improves in response to supplementation with monosodium glutamate. A mutant, in which the two listerial GAD homologs have been deleted (and in which there is no discernible GAD activity), did not respond to glutamate supplementation and displayed greatly enhanced sensitivity in a number of low pH foods, even when levels of free glutamate were as low as 0.22 mM. We thus show that the GAD system plays a major role in the survival of L. monocytogenes in acidic foods even when levels of free glutamate are low.

Colony Count, Microbial↗

PubMed2001

Physical therapy as primary health care: public perceptions.

This study investigated the public's knowledge of direct access and the role of physical therapists, and whether the public would consider using a physical therapist for primary care. Persons living in South Florida were selected at random by dialing telephone numbers. Using three-digit telephone number prefixes, four-digit suffixes were generated by rolling dice. When consent was obtained, the respondents' answers were recorded on a self-generated questionnaire. No knowledge of direct access was reported by 67.3% of the sample. Additionally, 57.4% of the sample had never been to a physical therapist. A substantial number of respondents (73.4%) stated that they would go directly to a physical therapist. Thus, the public poorly understands direct access and the role of the physical therapist. The members of the public might use physical therapists as primary care practitioners if they were aware of this option.

Adult↗

PubMed2001

[Evaluation of diagnostic methods].

AIM: Describe the statistical tools for the evaluation of a diagnostic test. MATERIAL AND METHODS: Description of the methods and practical examples based on published data. RESULTS: The following methods are described: 1) reproducibility of a measurement, both for a qualitative and a quantitative result, 2) comparison of a new diagnostic test to a reference test, 3) comparison of two diagnostic tests, 4) sample size computation. CONCLUSION: The tools required to evaluate diagnostic tests rigorously are available and simple. They should be used more often.

Data Interpretation, Statistical↗

PubMed2001

Toxic substances and reproductive disorders in Baltic fish and crustaceans.

In the Baltic Sea ecosystem reproductive disorders have occurred in top consumers such as seals and some fish-eating birds, due to biomagnification of toxic substances, e.g. DDT and PCBs. Reproductive disturbances have also affected fish during the last 25 years. However, there is no strong evidence that toxic substances have caused these problems. Rather, the disorders seem to result from a combination of two or more biotic or abiotic factors. The M74 syndrome, which kills fry of salmon and sea trout, is characterized by a deficiency of thiamine (vitamin B1). Several factors may contribute to the thiamine deficiency, including the diet of salmon in the sea and halogenated organic compounds. Cod do not develop M74, and poor cod recruitment is mainly due to poor oxygen conditions in the spawning areas in combination with overfishing. Toxic compounds in pulp-mill effluents retard gonadal development in perch, but the mechanisms and the active substances have not been identified. Recruitment problems in perch in the coastal waters outside some pulp mills may also be explained by a lack of food items for juvenile fish, rather than reproductive failure. There are very limited data on reproductive disorders in crustaceans from the Baltic Sea. Most data come from studies of the benthic amphipod Monoporeia affinis, which has been used in monitoring programs. Several signs of reproductive disorder have been reported in this amphipod, e.g. malformation and death of embryos, and asynchronous maturation of males and females.

Animals↗

PubMed2001

[Cancer prevalence in France].

To measure the frequency of cancer in a given country on a given year, one can use the number of new diagnosis or the number of deaths, but one can also consider the number of patients who have had a cancer diagnosed in the past and are still alive. This indicator is called prevalence. We present here estimations for the prevalence of cancer at 5 years in France, by sex and by site of cancer. These estimations are based on the number of new diagnoses in 1995 and on survival rates observed in Europe. In year 2000, 620,000 persons (310,000 men and 310,000 women) were followed up in France for a cancer diagnosed within the last 5 years. The most prevalent cancers were breast (136,000 cases), colorectal (91,000 cases) and prostate (83,000 cases) cancers.

Adolescent↗

PubMed2001

Assessment of hand-arm vibration syndrome in a northern Ontario base metal mine.

The objective of this study was to determine the prevalence of hand-arm vibration syndrome (HAVS) in 617 workers at a base metal mine in northern Ontario. Workers who were employed at the mine between the years 1989 and 1994 and who continued to live within a 100 km radius of the mine were sent a self-reported questionnaire to identify individuals with possible vibration-induced symptoms in their upper extremities. Of the 162 workers who attended the medical examination, 50% were diagnosed with HAVS, 26% had other diagnoses with some workers having multiple afflictions e.g., both HAVS and carpal tunnel syndrome (CTS). No vibration-induced symptoms were reported in 35% of the workers who were clinically normal. The study was designed to educate, advise, and to make recommendations on the prevention of HAVS. Ongoing commitments to technological improvements, mandatory and regular rest periods, and continuing educational sessions on the syndrome should help to reduce the prevalence of this disease.

Adult↗

PubMed2000

Rotavirus survival and stability in foods as determined by an optimised plaque assay procedure.

Tissue culture adapted rotavirus strains were propagated in MA104 and CaCo2 cells using standard cell culture procedures. The progress of infection was monitored by examining for a cytopathic effect, and for the presence of viral RNA in the tissue culture supernatant as determined by a guanidinium-based method. Subsequently, an effective plaque assay for rotavirus was developed using MA104 cells by optimising the adsorption time (2 h) and the levels of fetal calf serum (2.5%) in the overlay medium. Tragacanth gum was used in the overlay medium to immobilize the virus, and plaques were subsequently stained with 1% crystal violet. Using this optimised plaque assay, the survival of rotavirus following exposure to heat and UV irradiation was evaluated by enumerating the clear plaques. It was shown that 60 degrees C for 10 min was sufficient to reduce the viral titer by at least 7 logs, and 50 mJ of UV irradiation was sufficient to reduce the initial viral titer by > 2.5 logs. This optimised plaque assay was also used to determine the survival and stability of rotavirus from a range of experimentally contaminated foods including fruit juice, formula milk and lettuce.

Cell Line↗

PubMed2000

Low molecular weight heparin decreases rebound ischemia in unstable angina or non-Q-wave myocardial infarction: the Canadian ESSENCE ST segment monitoring substudy.

OBJECTIVES: The goal of this study was to determine whether enoxaparin was more effective than heparin in reducing recurrent ischemic episodes. BACKGROUND: Continuous ST segment monitoring is a simple tool for assessment of ischemia and identifies patients with a worse prognosis. Little is known about the impact of low molecular weight heparin on ST segment shift. METHODS: Patients were randomized to receive enoxaparin or heparin (mean 3.4 days). Three-lead ST segment monitoring was performed for the first 48 h (n = 220) and an additional 48 h (n = 174) after intravenous study drug discontinuation (mean 1.9 days later). RESULTS: During initial monitoring, ischemia rates were similar among the heparin and enoxaparin groups (27.2% vs. 22.6%, p = 0.44); however, the time to first ischemic episode was earlier among heparin-treated patients (11 +/- 11 vs. 25 +/- 18 min, p = 0.001). After drug discontinuation, ischemic episodes occurred more frequently (44.6% vs. 25.6%, p = 0.009), and the total ischemic duration was greater among heparin patients (18 +/- 39 vs. 5 +/- 12 min/24 h, p = 0.005). Recurrent ischemia occurred more frequently after discontinuation in the heparin (46% vs. 31%, p = 0.043), but not the enoxaparin, group (18.4% vs. 25%, p = 0.33). Regardless of treatment, patients with ischemia were more likely to die or experience (re)infarction at one year (18.4% vs. 8.3%, p = 0.023). CONCLUSIONS: ST segment shift occurs frequently in unstable angina/non-Q-wave myocardial infarction despite antithrombotic therapy and is associated with worse one-year prognosis. Enoxaparin is a more effective antithrombotic treatment than unfractionated heparin and leads to greater prevention of rebound ischemia.

Aged↗

PubMed2000

[Hormone replacement therapy in menopause and risk of breast cancer].

OBJECTIVES: Many epidemiological studies have analysed the relation between hormonal replacement therapy and risk of breast cancer. We present here a synthesis of the available results. MATERIAL AND METHODS: In 1997, a meta-analysis synthesised 90% of the data available at the time, obtained from 15 cohort and 36 case-control studies. This meta-analysis collected 53,000 breast cancers, 22% of these breast cancers having been observed in cohort studies. Since the publication of this meta-analysis, six studies totalling 8,000 cases (32% from cohort studies) have been published: two of these studies were partially included in the meta-analysis and the other four provided entirely new data. RESULTS: The conclusion, based on the available evidence, is that the risk of breast cancer diagnosis is higher among women who have used hormonal replacement therapy than among women who have not. The risk increases with treatment duration, is reduced when treatment is stopped and disappears almost completely a few years (5 in the meta-analysis) after the end of the treatment. The increase in the risk of breast cancer may be larger with estrogen-progestogen therapy than with estrogen alone. What are the consequences in terms of public health? From the results of the meta-analysis, one can estimate that the use of replacement therapy for 10 years between age 50 and 60 by 1,000 women will lead to the diagnosis of 6 extra breast cancers. This corresponds to the observation of 69 cases per 1,000 treated women after 20 years follow-up, as compared to the 63 cases expected among 1,000 untreated women. DISCUSSION: These results require confirmation. The observed increase in the risk of breast cancer is open to biases, particularly to a screening bias if women receiving hormonal replacement therapy have a more intensive surveillance than other women. Overall, the total number of women, across studies, who have received estrogen-progestogen therapy is small and their treatment was usually a combination of natural estrogens and medroxy progesterone acetate; therefore, the long term consequences of the treatments commonly used in France (synthetic estrogens and a variety of progestogens) have not been evaluated, this evaluation is much needed. CONCLUSION: What is needed is a global view of the risks and benefits of hormonal replacement therapy, and more epidemiologic data are required to reach this goal. In the present state of knowledge, the moderate excess risk of breast cancer observed does not justify a change in medical practice, neither in the selection of women to whom hormonal replacement therapy should be offered nor in the duration of their treatment.

Adult↗

PubMed2000

Tamoxifen adjuvant treatment duration in early breast cancer: initial results of a randomized study comparing short-term treatment with long-term treatment. Fédération Nationale des Centres de Lutte Contre le Cancer Breast Group.

PURPOSE: In 1986, The Fédération Nationale desCentres de Lutte Contre le Cancer Breast Group initiated a multicenter randomized trial to assess the usefulness of long-term adjuvant tamoxifen treatment. Short-term adjuvant tamoxifen treatment was to be compared with life long adjuvant tamoxifen treatment. PATIENTS AND METHODS: Patients who were disease-free after 2 to 3 years of adjuvant tamoxifen treatment were eligible for the trial. From September 1986 to May 1995, 3,793 patients were randomized from France, Belgium, and Argentina. A total of 1,882 patients stopped tamoxifen (short-term group), and 1,911 patients were to continue tamoxifen for life (long-term group) at the same dose as previously prescribed. The protocol was modified in February 1997, limiting tamoxifen treatment to 10 years after randomization, thus giving a comparison between a 2- to 3-year treatment and a 12- to 13-year treatment. To date, the median duration of tamoxifen treatment is 30 months in the short-term group, and 70 months in the long-term group. RESULTS: Overall, longer tamoxifen treatment induced a 23% reduction in relapse rates, leading to a 7-year disease-free survival rate of 78%, compared with 72% in the shorter-treatment group. In contrast, overall survival did not differ between the two groups, with a 79% overall survival rate in both groups. This improvement in disease-free survival could be observed in node-positive patients (P: =.001); however, it was not found in node-negative patients. Prolonged tamoxifen treatment corresponded to a significant increase in disease-free survival in estrogen receptor-positive patients (P: =.03) as well as in estrogen receptor-negative patients (P: =.05). Furthermore, longer treatment reduced contralateral breast cancers and did not increase the number of endometrial cancers. CONCLUSION: Although no survival advantage was noted, patients did benefit from longer tamoxifen treatment over 3 years and had significantly better disease-free survival compared with patients who stopped hormonal treatment. Long-term follow-up is needed to assess these results. Most patients in the long-term group are still receiving treatment. Comparison of results as time passes will enable conclusions to be made on the value of long-term treatment over 5 years compared with 2 to 3 years.

Antineoplastic Agents, Hormonal↗

PubMed2000

Analysis of the role of the Listeria monocytogenes F0F1 -AtPase operon in the acid tolerance response.

As little is known about the genes involved in the induction of an acid tolerance response in Listeria monocytogenes, the role of the F0F1-ATPase was analyzed as a consequence of its role in the acid tolerance of a number of other bacteria and its conserved nature. It was found that acid adapted cells treated with N,N'-dicyclohexylcarbodiimide (DCCD) exhibited greatly enhanced sensitivity to low pH stress. Degenerate primers were designed to amplify and sequence a portion of the atpD gene. Subsequently, a PCR product from atpA to atpD was identified. While we were unable to create a deletion in the atpA gene, the plasmid pORI19 was inserted in a region between atpA and atpG to reduce, rather than eliminate, expression of the downstream genes. As expected this mutant displayed enhanced resistance to neomycin and exhibited slower growth than the wild type strain. This mutant could still induce an acid tolerance response and remained susceptible to DCCD treatment, but its relative acid sensitivity was difficult to assess as a consequence of its slow growth.

Amino Acid Sequence↗

PubMed2000

Development of bioactive food packaging materials using immobilised bacteriocins lacticin 3147 and nisaplin.

Immobilisation of the bacteriocins nisin and lacticin 3147 to packaging materials was investigated. Stability of both cellulose-based bioactive inserts and anti-microbial polyethylene/polyamide pouches was examined over time. Anti-microbial activity against the indicator strain Lactococcus lactis subsp. lactis HP, in addition to Listeria innocua DPC 1770 and Staphylococcus aureus MMPR3 was observed for all bacteriocin-adsorbed materials. Activity retention of the inserts showed an initial decrease in the first week of storage but remained stable for the remaining 3 months of the trial. However, adsorption of lacticin 3147 to plastic film was unsuccessful, nisin bound well and the resulting film maintained its activity for 3-month period, both at room temperature and under refrigeration. When applied to food systems, the anti-microbial packaging reduced the population of lactic acid bacteria in sliced cheese and ham stored in modified atmosphere packaging (MAP) at refrigeration temperatures, thus extending the shelf life. Nisin-adsorbed bioactive inserts reduced levels of Listeria innocua by > or = 2 log units in both products, and Staphylococcus aureus by approximately 1.5 log units in cheese, and approximately 2.8 log units in ham. Similar reductions were observed in cheese vacuum-packaged in nisin-adsorbed pouches.

Animals↗

PubMed2000

Analysis of the role of betL in contributing to the growth and survival of Listeria monocytogenes LO28.

Survival of the food-borne pathogen Listeria monocytogenes in environments of elevated osmolarity and reduced temperature is attributed, at least in part, to the accumulation of the trimethylammonium compound glycine betaine. Previously we identified betL, a gene encoding the secondary glycine betaine transporter BetL, which we linked to the salt tolerance of Listeria. In this report, we demonstrate that betL, preceded by a consensus sigmaB-dependent promoter, is regulated by osmotic up-shock, at least in part at the level of transcription. Using allelic exchange mutagenesis we constructed an in-frame deletion in betL, and used this mutant to determine the role of BetL in contributing to the growth and survival of L. monocytogenes, both in a high risk food (Camembert cheese) and animal model. Our results indicate that while BetL plays an important role in glycine betaine mediated osmoprotection, mutating the gene does not significantly effect either the cryotolerance or virulence of the organism.

Animals↗

PubMed2000

Innovations in flap design: modified groin flap for closure of multiple finger defects.

The groin flap is frequently used for covering soft-tissue defects of the hand. It is normally utilised as a single unit to cover the defect. When used for coverage of multiple digital defects, it requires syndactylisation of the digits with a further procedure to divide the syndactylised digits some time after division of the main pedicle. We report a new technique of fashioning 'daughter flaps' from the groin flap at the time of elevation, and their use to cover full-thickness burns to the dorsum of PIP joints in both hands thus avoiding the need for syndactylisation of the digits.

Adult↗