PubMed Health⌕ Search

Biomedical subjects

C J Williams

Publications and source records attributed to C J Williams.

At least 19 recordsLinked to original sources
PubMed2006

Desmoplastic small round cell tumour: obstetric and gynecological presentations.

BACKGROUND: Desmoplastic small round cell tumour (DSRCT) is a rare sarcoma primarily affecting young men. We report two cases in young women mimicking gynaecological malignancy. CASES: A 23-year-old woman underwent caesarean section for obstructed labour. At surgery, multiple tumour deposits were found throughout abdomen and pelvis. Histology and PCR confirmed DSRCT. Despite chemotherapy, the patient relapsed and died 27 months after diagnosis. A 29-year-old woman presented with abdominal distension and elevated Ca125. Imaging demonstrated widespread tumour within abdomen and pelvis. Histology confirmed DSRCT. Although attaining a complete response to chemotherapy, she relapsed within 2 months and died 11 months after diagnosis. CONCLUSION: DSRCT should be considered in the differential diagnosis of young women presenting with abdominal distension and multiple masses on imaging.

Abdominal Neoplasms↗
PubMed2005

Precise determination of 6Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules.

We employ radio-frequency spectroscopy on weakly bound (6)Li(2) molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold (6)Li atoms based on a multichannel quantum scattering model. We determine the singlet and triplet scattering lengths to be a(s) = 45.167(8)a(0) and a(t) = -2140(18)a(0) (1a(0) = 0.052 917 7 nm), and the positions of the broad Feshbach resonances in the energetically lowest three s-wave scattering channels to be 83.41(15), 69.04(5), and 81.12(10) mT.

Journal Article↗
PubMed2003

Acid resistance of Escherichia coli O157:H7 from the gastrointestinal tract of cattle fed hay or grain.

There has been strong debate as to whether feeding cattle hay prior to slaughter will reduce the number and/or virulence of Escherichia coli O157:H7 in the bovine gastrointestinal tract (GIT). This study addressed this issue by comparing numbers, persistence, and acid resistance of generic coliforms and E. coli O157:H7 from various gastrointestinal tract sites of cattle fed grain or hay. Mature Angus steers, doubly cannulated into the rumen and duodenum were inoculated with E. coli O157:H7. Aliquots of digesta from the rumen, duodenum, and rectum were cultured directly or acid shocked (pH 2.0) and then cultured to determine acid resistance. The culture technique used was as sensitive as standard immunomagnetic bead separation protocols. E. coli O157:H7 from hay-fed or grain-fed cattle were similarly acid resistant in all GIT locations. In contrast, generic coliforms from the rumen and rectum of hay-fed animals were more sensitive to an acid shock than coliforms from those GIT locations in grain-fed animals. E. coli O157:H7 colonized the most distal region of the GIT and was not consistently cultured from the rumen or the duodenum. Numbers in the upper GIT did not predict numbers or persistence of E. coli O157:H7 in rectal samples. Grain-feeding or hay-feeding did not affect survival of E. coli O157:H7 in the rumen, nor its passage through the abomasum (pH 2.0) to the duodenum. These data show that generic coliforms behave differently in the bovine host than E. coli O157:H7 and that E. coli O157:H7 acid resistance was independent of animal diet.

Animal Feed↗
PubMed2003

Quantum information with neutral atoms as qubits.

One of the essential features of a quantum computer is a quantum 'register' of well-characterized qubits. Neutral atoms in optical lattices are a natural candidate for such a register. We have demonstrated a patterned-loading technique that can be used to load atoms into large arrays of tightly confined but optically resolvable lattice sites. We have also seen preliminary indications of the Mott-insulator transition, which provides a route for single-atom initialization of the individual sites. Combining the two experiments should allow for large arrays of individually addressable single atoms, a system which provides a starting point for further quantum computation studies.

Journal Article↗
PubMed2002

Creation of a molecular condensate by dynamically melting a Mott insulator.

We propose the creation of a molecular Bose-Einstein condensate by loading an atomic condensate into an optical lattice and driving it into a Mott insulator with exactly two atoms per site. Molecules in a Mott insulator state are then created under well defined conditions by photoassociation with essentially unit efficiency. Finally, the Mott insulator is melted and a superfluid state of the molecules is created. We study the dynamics of this process and photoassociation of tightly trapped atoms.

Journal Article↗
PubMed2002

The leatherback turtle, Dermochelys coriacea, exhibits both polyandry and polygyny.

The leatherback turtle (Dermochelys coriacea) is an endangered species, and world-wide populations are declining. To understand better the mating structure of this pelagic and fragile species, we investigated paternity in nearly 1000 hatchlings from Playa Grande in Parque Marino Nacional Las Baulas, Costa Rica. We collected DNA samples from 36 adult female leatherbacks and assessed allele frequency distributions for three microsatellite loci. For 20 of these 36 females, we examined DNA from hatchlings representing multiple clutches, and in some cases assessed up to four successive clutches from the same female. We inferred paternal alleles by comparing maternal and hatchling genotypes. We could not reject the null hypothesis of single paternity in 12 of 20 families (31 of 50 clutches), but we did reject the null hypothesis in two families (eight of 50 clutches). In the remaining six families, the null hypothesis could not be accepted or rejected with certainty because the number of hatchlings exhibiting extra nonmaternal alleles was small, and could thus be a result of mutation or sample error. Successive clutches laid by the same female had the same paternal allelic contribution, indicating sperm storage or possibly monogamy. None of 20 females shared the same three-locus genotype whereas there were two instances of shared genotypes among 17 inferred paternal three-locus genotypes. We conclude that both polyandry and polygyny are part of the mating structure of this leatherback sea turtle population.

Animals↗
PubMed2001

Survival and recurrence after concomitant chemotherapy and radiotherapy for cancer of the uterine cervix: a systematic review and meta-analysis.

BACKGROUND: The US National Cancer Institute alert in February, 1999, stated that concomitant chemotherapy and radiotherapy should be considered for all patients with cervical cancer. Our aim was to review the effects of chemoradiotherapy on overall and progression-free survival, local and distant control, and acute and late toxicity in patients with cervical cancer. METHODS: With the methodology of the Cochrane Collaboration, we did a systematic review of all known randomised controlled trials done between 1981 and 2000 (17 published, two unpublished) of chemoradiation for cervical cancer. FINDINGS: The trials included 4580 randomised patients, and 2865-3611 patients (62-78%) were available for analysis. Cisplatin was the most common agent used. The findings suggest that chemoradiation improves overall survival (hazard ratio 0.71, p<0.0001), whether platinum was used (0.70, p<0.0001) or not (0.81, p=0.20). A greater beneficial effect was seen in trials that included a high proportion of stage I and II patients (p=0.009). An improvement in progression-free survival was also seen with chemoradiation (0.61, p<0.0001). Thus, the absolute benefit in progression-free and overall survival was 16% (95% CI 13-19) and 12% (8-16), respectively. A significant benefit of chemoradiation on both local (odds ratio 0.61, p<0.0001) and distant recurrence (0.57, p<0.0001) was also recorded. Grade 3 or 4 haematological (odds ratio 1.49-8.60) and gastrointestinal (2.22) toxicities were significantly greater in the concomitant chemoradiation group than the control group. There was insufficient data to establish whether late toxicity was increased in the concomitant chemoradiation group. INTERPRETATION: Concomitant chemotherapy and radiotherapy improves overall and progression-free survival and reduces local and distant recurrence in selected patients with cervical cancer, which may give a cytotoxic and sensitisation effect.

Antineoplastic Agents↗
PubMed2001

Study of the mechanisms of cadmium biosorption by dealginated seaweed waste.

The ability of dealginated seaweed waste, a waste material derived from the commercial processing of seaweed for alginate production, to remove cadmium from solution was determined. Cadmium sorption was found to be rapid (91% removal within 5 min), achieving a residual concentration of 0.8 mg L-1 after 1-h contact time from an initial solution concentration of 10 mg L-1. The binding of cadmium by dealginate was found to be pH dependent, optimal sorption occurring at around pH 6-8. The mechanism of cadmium ion binding by dealginate was investigated by a number of techniques. Potentiometric titration of the dealginate revealed two distinct pKa values, the first having a value similar to carboxyl groups and the second comparable with that of saturated thiols and amines. Esterification of the dealginate resulted in the subsequent reduction in cadmium sorption (95% to 17%), indicating that carboxyl groups are largely responsible for sorption. Evidence from FT-IR spectra confirmed the presence of carboxyl groups in untreated dealginate, while the number of carboxyl groups was markedly reduced in the esterified sample. Furthermore, the FT-IR spectrum for dealginate was found to be similar to that previously reported for mannuronic acid-rich calcium alginate. Determination of a molar ratio in the displacement of calcium by cadmium on dealginate further supported the presence of an ion-exchange relationship. The ion-exchange constant was calculated to be 0.329 x 10(-6). The speciation of cadmium in solution both before and after sorption was determined by an ion-selective electrode (ISE) technique. The findings of this study suggest that the sorption of cadmium by dealginate is mainly due to an ion-exchange mechanism.

Adsorption↗
PubMed2001

Collisional frequency shifts in 133Cs fountain clocks.

We present a theoretical analysis of the density dependent frequency shift in Cs fountain clocks using the highly constrained binary collision model described by Leo et al. [Phys. Rev. Lett. 85, 2721 (2000)]. We predict a reversal in the clock shift at temperatures near 0.08 microK. Our results show that s waves dominate the collision process. However, as a consequence of the large scattering lengths in Cs the clock shift is strongly temperature dependent and does not reach a constant Wigner-law value until temperatures are less than 0.1 nK.

Journal Article↗
PubMed2001

Radical radiotherapy for stage I/II non-small cell lung cancer in patients not sufficiently fit for or declining surgery (medically inoperable).

BACKGROUND: In general, surgery is believed to offer the best prospects for cure for early stage non-small cell lung cancer (NSCLC). In spite of the intention to consider all patients with stage I-II disease for surgery, there are those who, although technically operable, either refuse surgery or are considered inoperable because of insufficient respiratory reserve, cardiovascular disease or general frailty. This group may therefore be considered "medically inoperable". Some respiratory physicians refer these patients for radical radiotherapy whilst others believe that radiotherapy has little to offer and adopt a watch policy, referring patients for palliative radiotherapy only when they become symptomatic. Although there is little evidence from randomised trials to support the use of radical radiotherapy for stage I/II NSCLC, it is the perception of most clinical oncologists (radiotherapists) that patients should receive radical, as opposed to palliative, treatment (COIN 1999). OBJECTIVES: To determine the effectiveness and the morbidity of radical radiotherapy for medically inoperable NSCLC. SEARCH STRATEGY: Randomised trials were sought by electronic searching the Cochrane Clinical Trials Register and both randomised and non-randomised trials sought by searching Medline and Excerpta Medica (Embase). Further studies were identified from references cited in those papers already identified by electronic searching. SELECTION CRITERIA: Studies of patients of any age with stage I/II NSCLC receiving radiotherapy at a dose greater than 40Gy in 20 fractions over four weeks or its radiobiological equivalent. DATA COLLECTION AND ANALYSIS: Two randomised and thirty-five non-randomised studies were identified. One randomised and nine non-randomised studies did not meet the selection criteria and were not included in the review. MAIN RESULTS: In the randomised trial comparing two radiotherapy schedules, two-year survival was superior following continuous hyperfractionated accelerated radiotherapy (CHART; 37%) compared to 60Gy in 30 fractions over six weeks (24%). There were 26 non-randomised retrospective studies including an estimated 2003 patients, in which overall survival results varied between 33-72% at two years, 17-55% at three years and 0-42% at five years. The proportion of deaths not due to cancer was 11-43%. Cancer-specific survival was between 54-93% at two years, 22-56% at three years and 13-39% at five years. Complete response rates were 33-61% and local failure rates between 6-70%. Distant metastases developed in approximately 25% of patients. Better response rates and survival were seen in those with smaller tumours and in those receiving higher doses though the reasons for prescribing higher doses were not clearly stated. Worse outcome was seen in those with prior weight loss or poor performance status. Assessment of treatment-related morbidity and effects on quality of life and symptom control were inconclusive because of the lack of prospective evaluation and paucity of data. REVIEWER'S CONCLUSIONS: There were no randomised trials that compared a policy of immediate radical radiotherapy with palliative radiotherapy given when patients develop symptoms. In the absence of such trials, radical radiotherapy appears to result in a better survival than might be expected had treatment not been given. A substantial, though variable, proportion of patients died during follow-up from causes other than cancer. The optimal radiation dose and treatment technique (particularly with respect to mediastinal irradiation) remain uncertain.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

Men sex workers and other men who have sex with men: how do their HIV risks compare in New Zealand?

Sex workers have their perspective on HIV transmission, claiming that in general they are more similar than different from other people in HIV status and the practice of safe sex. Such an assertion of similarity goes against public and professional opinion that prostitution is a major vector in the spread of AIDS. Taking the sex workers' similarity claim seriously, this paper considers the conditions under which it would be valid. We focus on those factors that make a population more or less vulnerable to HIV and how they affect its spread into the sex work population. Data from New Zealand comparing men sex workers and other men who have sex with men is used to evaluate these ideas. Data partially support the hypothesis in that these two groups of men are similar with regard to their HIV status. We do find the sex workers to be different, however, in their being less likely to engage in safe sex practices. We provide an explanation for why this has not lead to their having a higher rate of seropositivity.

Adult↗
PubMed2001

Irradiation promotes V(D)J joining and RAG-dependent neoplastic transformation in SCID T-cell precursors.

Defects in the nonhomologous end-joining (NHEJ) pathway of double-stranded DNA break repair severely impair V(D)J joining and selectively predispose mice to the development of lymphoid neoplasia. This connection was first noted in mice with the severe combined immune deficient (SCID) mutation in the DNA-dependent protein kinase (DNA-PK). SCID mice spontaneously develop thymic lymphoma with low incidence and long latency. However, we and others showed that low-dose irradiation of SCID mice dramatically increases the frequency and decreases the latency of thymic lymphomagenesis, but irradiation does not promote the development of other tumors. We have used this model to explore the mechanistic basis by which defects in NHEJ confer selective and profound susceptibility to lymphoid oncogenesis. Here, we show that radiation quantitatively and qualitatively improves V(D)J joining in SCID cells, in the absence of T-cell receptor-mediated cellular selection. Furthermore, we show that the lymphocyte-specific endonuclease encoded by the recombinase-activating genes (RAG-1 and RAG-2) is required for radiation-induced thymic lymphomagenesis in SCID mice. Collectively, these data suggest that irradiation induces a DNA-PK-independent NHEJ pathway that facilitates V(D)J joining, but also promotes oncogenic misjoining of RAG-1/2-induced breaks in SCID T-cell precursors.

Animals↗
PubMed2001

Radical radiotherapy for stage I/II non-small cell lung cancer in patients not sufficiently fit for or declining surgery (medically inoperable): a systematic review.

OBJECTIVES: To determine the effectiveness of radical radiotherapy in medically inoperable stage I/II non-small cell lung cancer (NSCLC) and the extent of treatment related morbidity. METHODS: Randomised trials were sought by electronically searching the Cochrane Clinical Trials Register, and both randomised and non-randomised trials were sought by searching Medline and Excerpta Medica (Embase). Further studies were identified from references cited in those papers already identified by electronic searching. The studies included were those of patients of any age with stage I/II NSCLC receiving radiotherapy at a dose of >40 Gy in 20 fractions over 4 weeks or its radiobiological equivalent. RESULTS: Two randomised and 35 non-randomised studies were identified. One randomised and nine non-randomised studies did not meet the selection criteria, leaving one randomised and 26 non-randomised studies for analysis. In the randomised trial 2 year survival was higher following continuous hyperfractionated accelerated radiotherapy (CHART; 37%) than following 60 Gy in 30 fractions over 6 weeks (24%). An estimated 2003 patients were included in the 26 non-randomised studies; overall survival was 22-72% at 2 years, 17-55% at 3 years, and 0-42% at 5 years. Following treatment, 11-43% of patients died from causes other than cancer. Cancer specific survival was 54-93% at 2 years, 22-56% at 3 years, and 13-39% at 5 years. Complete response rates were 33-61% and local failure rates were 6-70%. Distant metastases developed in approximately 25% of patients. Better response rates and survival were seen in those with smaller tumours and in those receiving higher doses although the reasons for prescribing higher doses were not clearly stated. The outcome was worse in those with prior weight loss or poor performance status. Assessment of treatment related morbidity and effects on quality of life and symptom control were inconclusive because of the lack of prospective evaluation and paucity of data. CONCLUSIONS: No randomised trials compared a policy of immediate radical radiotherapy with palliative radiotherapy given when patients develop symptoms. In the absence of such trials, radical radiotherapy appears to result in a better survival than might be expected had treatment not been given. A substantial, though variable, proportion of patients died during follow up from causes other than cancer. The optimal radiation dose and treatment technique (particularly with respect to mediastinal irradiation) remain uncertain.

Adult↗
PubMed2000

Tamoxifen for relapse of ovarian cancer.

BACKGROUND: Tamoxifen is an important drug for treating breast cancer. Ovarian cancer cells are known to possess receptors for hormones and may thus also respond to tamoxifen. OBJECTIVES: Tamoxifen is used to treat breast cancer in women whose tumours have oestrogen receptors. Since ovarian cancers also commonly have oestrogen receptors, it has been suggested that tamoxifen may be of some benefit. The objective of this review was to assess the effects of tamoxifen in women with relapsed ovarian cancer. SEARCH STRATEGY: We searched the Cochrane Gynaecological Cancer Group trials register and references from relevant articles. We also contacted researchers and drug companies. SELECTION CRITERIA: Randomised and non-randomised studies of tamoxifen in women with ovarian cancer who have not responded to conventional chemotherapy. Only trials involving 10 or more patients were included. DATA COLLECTION AND ANALYSIS: One reviewer assessed eligibility and extracted data from non-randomised studies. Two reviewers were to have independently assessed the quality and extracted data from any randomised trials found. MAIN RESULTS: Eleven non-randomised series, one non-randomised phase two study and one randomised trial were included. Only observational data from women treated with tamoxifen are reported. Fifty-nine of 568 women (10.4%) treated with tamoxifen achieved an objective response to treatment. However this varied from 0% to 56% in different studies. Stable disease, for variable periods of four weeks or more, was observed in 109 of 356 (30.6%) women from eight studies. There were not enough data to assess duration of response, survival, or the palliative effect of tamoxifen on symptom control or quality of life. REVIEWER'S CONCLUSIONS: There is some evidence from observational studies that tamoxifen may produce a response in a modest proportion of women with relapsed ovarian cancer. However, there are no reliable data from randomised controlled trials.

Antineoplastic Agents, Hormonal↗
PubMed2000

Evaluation of application methods for control of Aspergillus fumigatus proliferation on the air cell membrane of in ovo injected broiler eggs.

Three different techniques of applying fungicides and mold inhibitors were evaluated as control methods for Aspergillus fumigatus proliferation on the air cell membrane of eggs that were infertile or contained early dead embryos following in ovo egg injection. A controlled Aspergillus challenge model was utilized that simulates the natural occurrence of fungal growth following in ovo egg injection. Methods of application examined were egg shell spray, direct air cell application prior to Aspergillus challenge, and micro-aerosol fogging in the incubation compartment during Aspergillus challenge. Fungicides and mold inhibitors used included propionic acid, propionic acid plus ammonia, phenol, quaternary ammonium plus organic tin, hydrogen peroxide, enilconazole, and an aromatase inhibitor. When applied as egg shell spray treatments or micro-aerosol fog treatments, none of the products that were tested significantly reduced the incidence of mold proliferation on the air cell membrane when compared with untreated, but otherwise challenged, controls. When applied directly to the air cell membrane prior to fungal challenge, only enilconazole and the aromatase inhibitor significantly reduced the incidence of fungal proliferation when compared with appropriate controls.

Aerosols↗
PubMed2000

Development of a model to study Aspergillus fumigatus proliferation on the air cell membrane of in ovo injected broiler eggs.

A model was developed to examine the proliferation of Aspergillus fumigatus on the air cell membrane of broiler hatching eggs and to assay the effectiveness of fungal control strategies that may be used in conjunction with late embryonic egg injection. Egg yolk was identified as the nutritive media required to sustain fungal growth. Incubation was required to predispose the egg to fungal infection by allowing the yolk to come into contact with the air cell membrane. Infertile eggs and eggs containing embryos that died before 4 d of incubation (early-dead) that had been subsequently incubated for 9 d or more were equally susceptible to fungal infection. In order to evaluate potential methods of control, these eggs were punched through the blunt end of the shell with a 16-gauge needle, placed into forced-air incubators (hatchers), and exposed to air-dispersed pure cultures of A. fumigatus. The frequency of eggs exhibiting mold growth on the air cell membrane 72 h after exposure was subjected to a Chi-square analysis model. The effect of egg position within an incubator flat in relationship to the A. fumigatus source culture, the variation between flats (levels) within a given hatcher, the variation between hatchers, and the variation between replicate trials were measured and found to be potential sources of experimental error that must be minimized in order to accept the results of an evaluation. A statistically valid model was developed that can be used to evaluate various types of fungicidal treatments of hatching eggs and their relative efficacy in association with egg injection.

Animals↗
PubMed2000

Ruminant gastrointestinal cell proliferation and clearance of Escherichia coli O157:H7.

Human infections with Escherichia coli O157:H7 cause hemorrhagic colitis that can progress to a life-threatening sequelae. The most common mode of disease transmission is ingestion of contaminated bovine food products, and it is well established that E. coli O157:H7 is a transient member of the bovine microbiota. However, the conditions that induce acquisition and subsequent clearance of this bacterium from the ruminant gastrointestinal tract (GIT) are not understood. Evidence that the rates of epithelial cell proliferation in the lower GIT of cattle are associated with the duration animals remained E. coli O157:H7 culture positive is presented. Cattle with slower rates of intestinal cell proliferation in the cecum and the distal colon were culture positive significantly longer than cohort cattle with faster cell proliferation rates. Cell death rates (apoptotic indices) between the short- and long-term culture-positive animals were not different. Typical grain-based finishing diets and forage-based growing diets did not effect GIT cell proliferation or the duration animals remained E. coli O157:H7 culture positive. To identify a dietary intervention that would effect GIT cell proliferation, we used sheep as a model ruminant. A fasting-refeeding regime that increased the rate of GIT cell proliferation was developed. The fasting-refeeding protocol was used in cattle to test the hypothesis that feeding interventions that increase the rate of GIT cell proliferation induce the clearance of E. coli O157:H7 from the bovine GIT.

Animal Feed↗