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Biomedical subjects

Y Williams

Publications and source records attributed to Y Williams.

At least 19 recordsLinked to original sources
PubMed2005

Yeast-derived sigma C protein-induced immunity against avian reovirus.

Avian reoviruses (ARVs) can result in disease and economic losses in the poultry industry. Vaccines against ARV may not provide full protection and can cause adverse reactions. The coding sequence of the sigma C protein from strain S1133 of avian reovirus was expressed in Schizasaccharomyces pombe. Sigma C protein expression was demonstrated by Western blotting, and the protein was evaluated for its ability to protect specific-pathogen-free (SPF) chickens against challenge with the virulent S1133 strain. Serologic and challenge-infection data showed the efficacy of the recombinant vaccine administered orally each week for 3 consecutive wk. Sigma C protein induced antibody, as determined by enzyme-linked immunosorbent assay. Percentage (%) protection induced by the low dose (125 microg purified yeast-expressed sigma C protein/chicken) or the high dose (250 microg purified yeast-expressed sigma C protein/chicken) was 64 and 91, respectively. The commercial vaccine administered once or twice provided 82% protection. Results supported the feasibility of a plant-derived vaccine for use in poultry immunization schemes.

Animals↗
PubMed2004

Deletion of chromosome arm 15q and hitherto unreported duplication of del(15q) in myeloid disorders.

Deletion of the long arm of chromosome 15 has been described as a recurrent chromosomal abnormality in myeloid malignancies. We present here some additional case reports of deletion 15 including two cases with an extra copy of the deleted chromosome, a finding that has not previously been described. We compare our cases to those previously reported. Our findings show that, contrary to previous reports, this abnormality may not always be associated with an unfavorable prognosis. They also indicate that deletion 15q most frequently appears to be associated with myelomonocytic disease. Potential candidate genes on 15q that may be involved in the tumorigenesis of these cases are discussed.

Acute Disease↗
PubMed2004

Levels of mental health problems among UK emergency ambulance workers.

This study examined the prevalence of post-traumatic stress disorder (PTSD), depression, and anxiety in a sample of emergency ambulance personnel. Of 1029 personnel in one ambulance service mailed a questionnaire, 617 were returned. Among respondents, the overall rate of PTSD was 22%. Levels of PTSD did not differ according to grade, but men had a higher prevalence rate than women (23% compared with 15%). Nearly one in ten reported probable clinical levels of depression, 22% reported probable clinical levels of anxiety based on Hospital Anxiety and Depression Scale scores.

Adult↗
PubMed2001

Impaired IgG responses in a child with homozygous C2 deficiency and recurrent pneumococcal septicaemia.

Homozygous deficiency of the second component of complement (C2) is the most common inherited deficiency of complement. Although C2 deficiency has been detected in asymptomatic individuals, patients usually present with either autoimmune disease or recurrent pyogenic infection, particularly due to encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis. Interestingly, infection is the most common mode of presentation of C2 deficiency in young children (1). An association between C2 deficiency and IgG subclass deficiency has also been previously described. We now report a female child with C2 deficiency that presented at the age of 3 mo with recurrent pneumococcal septicaemia. Although IgG subclass levels were normal, specific IgG responses to vaccination against S. pneumoniae and H. influenzae were significantly impaired.

Complement C2↗
PubMed2001

Laboratory evaluation of two native fishes from tropical North Queensland as biological control agents of subterranean Aedes aegypti.

The ability of 2 freshwater fishes, eastern rainbow fish Melanotaenia splendida splendida and fly-specked hardyhead Craterocephalus stercusmuscarum stercusmuscarum, native to North Queensland to prey on immature Aedes aegypti was evaluated under laboratory conditions. The predation efficiency of the 2 species was compared to the exotic guppy, Poecilia reticulata, which is commonly used as a biological control agent of mosquito larvae. Of the 3 fish species tested, M. s. splendida was shown to be the most promising agent for the biological control of Ae. aegypti that breed in wells. Melanotaenia s. splendida consumed significantly greater numbers of immature Ae. aegypti than P. reticulata, irrespective of developmental stage or light conditions. Unlike C s. stercusmuscarum, M. s. splendida could be handled, transported, and kept in captivity for extended periods with negligible mortality. However, M. s. splendida was also an efficient predator of Litoria caerulea tadpoles, a species of native frog found in wells during the dry season. This result may limit the usefulness of M. s. splendida as a biological control agent of well-breeding Ae. aegypti and suggests that predacious copepods, Mesocyclops spp., are more suitable. However, the use of M. s. splendida as a mosquito control agent in containers that are unlikely to support frog populations (e.g., aquaculture tanks and drinking troughs) should be given serious consideration.

Aedes↗
PubMed2000

Symptomatic and asymptomatic chlamydial non-gonococcal urethritis in Jamaica: the potential for HIV transmission.

To determine the contribution of Chlamydia trachomatis to non-gonococcal urethritis (NGU) in men attending sexually transmitted disease (STD) clinics in Jamaica we studied men with NGU (n=339), and control groups including asymptomatic men who were STD contacts (n=61), asymptomatic men who were not STD contacts (n=32) and men with gonococcal urethritis (GU) (n=61). Urethral specimens were examined for C. trachomatis and Neisseria gonorrhoeae. Serological tests for syphilis (STS) and HIV-1 infection were also performed. C. trachomatis accounted for 63% of cases of NGU but high prevalences were also found in asymptomatic STD contacts (59%), asymptomatic STD non-contacts (78%) and men with GU (48%). The prevalence of C. trachomatis in men with GU differed significantly from that in men with NGU and asymptomatic STD non-contacts (P<0.05). C. trachomatis infection in men with NGU was associated with multiple sex partners (71% vs 58%; chi2=4.78; odds ratio (OR)=1.76; P<0.05) and previous history of gonococcal infection (83% vs 42%; chi2=59.8; OR=6.8; P<0.0001). Concomitant infection with HIV-1 occurred in 5.2% of cases of NGU and 50% and 90%, respectively, of the HIV-positive men had chlamydia or reactive STS. As a cost effective strategy in the control of STD and HIV we recommend presumptive treatment for C. trachomatis in men seeking STD treatment in Jamaica.

Case-Control Studies↗
PubMed1998

Correlation of platelet Fc gammaRIIA polymorphism in refractory idiopathic (immune) thrombocytopenic purpura.

Fc gammaRIIA, a low affinity receptor for IgG, is a polymorphic molecule: Fc gammaRIIA-HH131, Fc gammaRIIA-HR131 and Fc gammaRIIA-RR131. This polymorphism influences the efficiency of the receptor to bind with IgG2. Recent reports on altered distribution amongst individuals with heparin-induced thrombocytopenia (HIT) prompted us to examine the Fc gammaRIIA polymorphism in a cohort of patients with refractory idiopathic (immune) thrombocytopenic purpura (ITP), in whom severe disease had required them to undergo splenectomy. 29 post splenectomy ITP individuals and 61 normal controls were investigated. Polymerase chain reaction (PCR) and a Southern blotting technique were used to determine the Fc gammaRII polymorphism. Although the distribution of the allotypes of Fc gammaRIIA in the control population was similar to that found in other European studies of Caucasian populations (15 (25%) HH131; 35 (57%) HR131; 11 (18%) RR131), the patient group was skewed towards the RR131 allotype which has least efficiency for IgG2 binding (3 (10%) HH131; 12 (42%) HR131; 14 (48%) RR131; P<0.005). These findings suggest that Fc gammaRIIA polymorphisms may be implicated in the pathophysiology of ITP or may be responsible for modulating the immune response in this heterogeneous autoimmune disease.

Adolescent↗
PubMed1998

Working with parents to promote health.

A cleft lip, with or without cleft palate, is the most common craniofacial malformation. The issue of whether health can be attained if the person has a physical defect is discussed. Health education can be considered as a means whereby individuals learn to maintain, restore and promote health. Consideration is given to health promotion and the prevention of ill health in relation to infant feeding. Skill teaching, if successfully completed, may be regarded as a fundamental cornerstone to health promotion.

Adult↗
PubMed1998

Is HIV/STD control in Jamaica making a difference?

OBJECTIVE: To assess the impact of the comprehensive HIV/STD Control Program established in Jamaica since the late 1980s on the HIV/AIDS epidemic. METHODS: AIDS case reports, HIV testing of blood donors, antenatal clinic attenders (ANC), food service workers, sexually transmitted disease (STD) clinic attenders, female prostitutes, homosexuals and other groups were used to monitor the HIV/AIDS epidemic. Primary and secondary syphilis and cases of congenital syphilis were also monitored. National knowledge, attitude and practice (KAP) surveys were conducted in 1988, 1989, 1992, 1994 and 1996. RESULTS: The annual AIDS incidence rate in Jamaica increased only marginally in the past three years from 18.5 per 100000 population to 21.4 in 1997. HIV prevalence in the general population groups tested has been about 1% or less. Among those at high risk, HIV prevalence rates have risen to 6.3% (95% confidence interval 5.0-8.0) in STD clinic attenders, around 10% and 21% in female prostitutes in Kingston and Montego Bay respectively and approximately 30% among homosexuals. Syphilis rates and congenital syphilis cases have declined. The proportion of men aged 15-49 years reporting sex with a non-regular partner declined from 35% in 1994 to 26% in 1996 (P< 0.001). Women ever having used condoms increased from 51% in 1988 to 62.5% in 1992 and 73% in 1994 and 1996 (P< 0.001), while condom use with a non-regular partner increased from 37% in 1992 to 73% in 1996 (P= 0.006). Condom use among men was high over the period: around 81% had ever used condoms and 77% used them with non-regular partners. Gay men, inner-city adults and adolescents aged 12-14 years all reported increases in condom use while condom sales and distribution increased from around 2 million in 1985 to 10 million in 1995. CONCLUSION: HIV/STD control measures appear to have slowed the HIV/AIDS epidemic in Jamaica, however a significant minority of persons continue to have unprotected sex in high risk situations.

Adolescent↗
PubMed1995

Tetanus immunity in elderly people.

The aims of this study were to document the level of tetanus immunity in elderly people; to assess the value of immunization history in predicting tetanus immune status and to determine the response to tetanus immunization in elderly people compared with younger subjects. One-hundred day-hospital attenders (group 1), 100 long-term-care residents (group 2) and 50 young subjects (group 3) were recruited. Protective titres of tetanus antitoxin antibodies were detected in 20% of group 1, 45% of group 2 and 80% of group 3. Tetanus immunization history was a poor predictor of immune status in older people with a positive predictive value of 50% and a negative predictive value of 76%. The response to tetanus immunization was slower and of lower magnitude in older people. However, 36 of 37 older subjects developed protective levels of tetanus antitoxin antibodies on completion of a primary immunization programme.

Adult↗
PubMed1995

Management of vaginal discharge in women treated at a Jamaican sexually transmitted disease clinic: use of diagnostic algorithms versus laboratory testing.

The management of cervical infections is difficult in developing countries because laboratory facilities for diagnosing these infections are seldom available; therefore, syndrome-based management has been recommended by the World Health Organization (WHO). However, such alternative approaches need to be evaluated in real field settings. We used algorithms (flowcharts) for syndromic management of abnormal vaginal discharge to treat 752 women who presented at a Jamaican sexually transmitted disease (STD) clinic. Laboratory testing revealed cervical infection (gonococcal and/or chlamydial) in 34% of these women; trichomoniasis was documented for 25%; and at least one STD was documented for 54% of the women. Use of a clinical algorithm for diagnosing cervical infection was 73% sensitive (95% CI, 67-78) and 55% specific (95% CI, 49-62) when compared with laboratory testing. The risk-assessment-inclusive flowchart developed by WHO was 84% sensitive (95% CI, 80-89) and 40% specific (95% CI, 34-46) for diagnosing cervical infection. Positive predictive values for diagnosing cervical infection with use of the algorithms ranged from 42% to 43%, and negative predictive values ranged from 78% to 81%. The sensitivity of the algorithms for diagnosing trichomoniasis ranged from 85% to 88%. To treat as many infected women as possible, the most sensitive algorithm was selected for routine use in Jamaican STD clinics.

Adult↗
PubMed1994

Competitive elution of protein A fusion proteins allows specific recovery under mild conditions.

A novel system is described for mild elution of fusion proteins by competitive elution. The approach is based on displacement of immobilized fusions containing a monovalent IgG-binding staphylococcal protein A fragment (Z) from an IgG-affinity matrix by a divalent fragment fused to a serum-albumin-binding region derived from streptococcal protein G. Using real-time interaction analysis, the binding (K(aff)) to polyclonal human IgG was found to be 3.3 (+/- 0.4) x 10(8) M-1 for divalent ZZ and 2.0 (+/- 0.1) x 10(7) M-1 for monovalent Z. This more than tenfold difference in binding strength ensures a high efficiency in the elution step. The competitor protein can specifically be removed and recovered from the elution mixture by subsequent passage through a human serum albumin(HSA)-affinity column, leaving only the target fusion protein in the flow-through fraction. Here, we show that a recombinant Klenow fragment of DNA polymerase I expressed in Escherichia coli can be recovered with high yield, and retained activity, from a crude bacterial lysate by IgG-affinity chromatography using mild conditions during both binding and elution.

Base Sequence↗
PubMed1988

Five year follow-up of patients with cancer of the bladder--the Northern Alberta experience.

A prospective study of 549 cases of bladder cancer diagnosed in Northern Alberta from 1977 to 1980 shows that after 5 years, 51 patients (9.3%) were lost to follow-up, 318 (57.9%) were alive, and 180 (32.8%) were deceased, of which 98 had died of bladder cancer and 82 of other causes. Of the patients followed for 5 years, 386 had superficial disease at diagnosis. When comparing their survival rates to the expected rates for age/sex matched population, their relative survival rate at 5 years is 84.8% for females and 74.2% for males. For the 112 patients presenting with advanced disease the relative survival rate at 5 years was 32.2% for females and 19.3% for males. Five year recurrence-free interval in patients with superficial lesions was 57.3% when the original lesion was unifocal and 33.5% for patients with multifocal lesions. Survival was affected by stage, age, and sex in patients presenting with invasive disease and also by tumor type and recurrence rate in patients with superficial disease.

Adult↗
PubMed1986

Effect of lithium therapy on inflammatory response.

Chemiluminescence produced by normal cells was reduced in response to zymosan which was opsonized with serum from patients on prophylactic lithium therapy, compared to control serum from normal subjects (68 +/- 3.1 vs. 93 +/- 3.4 mV/5 X 10(5) cells). Preincubation of normal cells with serum from patients also resulted in reduced chemiluminescence activity when the cells were stimulated with autologous serum-coated zymosan (47 +/- 4.5 vs. 64 +/- 6.3 mV/5 X 10(5) cells). Spontaneous complement conversion was increased in the serum of patients on lithium therapy (46.3 +/- 3.8 vs. 25.3 +/- 2.5% conversion). These studies demonstrated that lithium, at safe therapeutic levels (0.4-0.9 mmol/liter), significantly altered complement conversion and had a marked affect on chemiluminescence activity by normal cells.

Adult↗