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Biomedical subjects

B G Evans

Publications and source records attributed to B G Evans.

At least 55 records · Page 3Linked to original sources
PubMed1995

People who travel to be treated for HIV infection: keeping track for care management.

An HIV information exchange was established to provide district health authorities (DHAs) with current demographic and epidemiological data on residents infected with HIV. Reporters in each DHA in the Thames regions were asked to collect information about all HIV infected individuals treated within their districts during 1993. The information was collated at the PHLS AIDS Centre and summary tables were distributed to the DHAs involved describing their residents. We received reports of 7760 people infected with HIV and who were treated in the Thames regions in 1993. Thirty-five per cent were treated outside the region where they lived, 22% were treated within their region but outside their district of residence, and 43% were treated in the DHA where they lived. For 30 of the 38 DHAs the number of resident patients exceeded the number treated within the district. This exchange of information between DHA of treatment and DHA of residence showed that it is possible to provide summaries of current HIV case loads based on place of residence without compromising confidentiality. It also confirmed that many patients choose to be treated away from their area of residence.

Adolescent↗
PubMed1995

Birth weight and special educational needs: effects of an increase in the survival of very low birthweight infants in London.

OBJECTIVES: To assess the contribution of children with different birth weights to special educational needs within a single health district, and to determine whether this pattern changed over the time when the survival of very low birthweight (VLBW) infants was increasing. SETTING: An inner London health district. STUDY DESIGN: A cohort of children born to local parents between January 1974 and December 1980 was selected from birth notifications, including only those infants who survived for more than one month. Community child health records were then inspected to identify children from the cohort who had been formally assessed for special educational needs before their 8th birthday. The risk of special educational needs was compared for the years 1974-77 and 1977-80 (the first and second halves of the period studied). SUBJECTS: The infant cohort consisted of 31,846 children. Altogether 260 (0.8%) of these were later assessed formally. RESULTS: VLBW infants were 4.4 times more likely to be assessed than normal birthweight infants. Formal assessment within the district occurred in three of 68 VLBW infants from the first half of the period studied, and three of 120 from the second half. CONCLUSION: Although VLBW infants are at higher risk, an increase in their survival was not associated with any increase in their contribution to the group with special educational needs within our district. Their contribution, as a group, to the total number of children with special educational needs is very small.

Birth Weight↗
PubMed1995

Complications of femoral and acetabular modularity.

The versatility of modular total hip arthroplasties have rapidly extended their applications. However, these new interfaces can lead to complications that were not observed with monolithic components. These problems have been noted with modular femoral and acetabular components and have been associated with the generation of particulate debris. This article reviews the authors' clinical observations and histologic, biomechanic, and spectophotometric evaluations of modular total hip arthroplasties. New data comparing both synovial fluid metal levels in well-fixed and loose monolithic and modular prosthetic hip implants are presented. In modular total hip components, synovial fluid cobalt levels correlated positively with patient weight and length of implantation. The generation of particulate debris in modular total hip components may induce periprosthetic osteolysis. Taper locks for femoral components and locking mechanisms for the polyethylene liner and metallic cup must be designed to avoid the production of particulate debris.

Acetabulum↗
PubMed1994

Palacos gentamicin for the treatment of deep periprosthetic hip infections.

Between 1983 and 1986, 40 hip arthroplasties in 40 patients with documented deep infection were reimplanted using Palacos Gentamicin at The Hospital for Special Surgery. Palacos Gentamicin was added to the standard protocol, which included removal of the prosthesis, cement, if present, and a thorough debridement of infected and necrotic tissue, six weeks of intravenous antibiotics with a postpeak serum bactericidal titer of at least 1:8 against the infecting bacteria, followed by reimplantation of the hip. Sixteen of the patients also had the placement of gentamicin-impregnated beads at the time of prosthetic removal. All patients had a deep periprosthetic infection, 13 with Staphylococcus epidermidis, seven Staphylococcus aureus, four Streptococcus, three Enterococcus, three with gram-positive bacteria, four Escherichia coli, two Proteus, one Pseudomonas, and three anaerobic organisms. At an average follow-up period of five years (range, two to ten), two of the 40 hips (5%) developed recurrent infection. These cases recurred at one month in a patient immunocompromised by end-stage systemic lupus erythematosus (S. epidermidis) and at five months in a patient with severe titanium metallosis (S. aureus). No recurrence was noted in eight cases with gram-negative organisms or in three cases of mixed infections. No infection recurred after five months in the remaining patients before their death or last follow-up examination. Of the remaining 38 hips, 16 died of causes unrelated to the hip, leaving 21 with an average follow-up period of 7.5 years. Clinical results in these patients were 14 excellent, five good, two fair, and no poor results.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Total hip replacement in the elderly: cost-effective alternatives.

The cost of the prosthetic components can represent approximately 15% to 25% of the total cost of hospitalization, depending upon whether cemented or cementless fixation is selected. The excellent long-term clinical data of cemented fixation and the cost of the implants clearly favor cemented fixation for total hip arthroplasty in the elderly patient.

Age Distribution↗
PubMed1993

Factors associated with lack of awareness of HIV infection before diagnosis of AIDS.

OBJECTIVE: To identify characteristics of people likely to be unaware of their HIV infection before diagnosis of AIDS defining disease. DESIGN: Survey of continuing surveillance of voluntarily reported AIDS cases. SUBJECTS: 4127 adults with AIDS diagnosed during 1989-92 and reported to the Public Health Laboratory Service AIDS Centre. SETTING: England and Wales. MAIN OUTCOME MEASURE: Lack of prolonged awareness of infection before diagnosis of AIDS, defined as an interval of nine months or less between first positive test result and diagnosis of AIDS. RESULTS: Of 3556 adults with known dates of first positive HIV test result and AIDS diagnosis, 1742 (49%) had been unaware of their infection for up to nine months before AIDS was diagnosed. Lack of awareness was independently and positively associated with infection through heterosexual contact (odds ratio 4.46, 95% confidence interval 3.15 to 6.33), AIDS reported outside the Thames regions (1.64, 1.38 to 1.96), and being non-white (1.99, 1.51 to 2.61). Women were less likely to be unaware than men (0.50, 0.33 to 0.76), and people diagnosed in 1992 were least likely to be unaware (0.48, 0.39 to 0.60). Those aged 25-49 years at diagnosis were less likely to be unaware than those aged 15-24 years and those aged 50 and over. CONCLUSIONS: People with certain characteristics are more likely than others to be unaware of their HIV infection before AIDS is diagnosed and are therefore less likely to receive prophylaxis. Methods for educating this heterogeneous group need to be investigated.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Sexually transmitted diseases and HIV-1 infection among homosexual men in England and Wales.

OBJECTIVE: To examine surveillance data for evidence of changing sexual behaviour and continuing transmission of HIV-1 among men who have sex with men. DESIGN: Analytic study of surveillance data on sexually transmitted diseases. SETTING: England and Wales. MAIN OUTCOME MEASURES: Number of cases of rectal gonorrhoea and newly diagnosed HIV infection in homosexual men. RESULTS: New cases of gonorrhoea among men attending genitourinary medicine clinics increased by 7.7% in 1989 and by 4.2% in 1990. Reports of rectal isolates of Neisseria gonorrhoeae also rose and the male to female ratio for patients with rectal gonorrhoea changed from 0.3:1 during 1988-9 to 2.6:1 in 1990-1. Although the overall number of cases of acute hepatitis B fell during 1988-91, 81 and 82 homosexual men were infected in 1990 and 1991 respectively compared with 50 and 42 in 1988 and 1989. 1526 men had HIV-1 infection diagnosed in 1991, the largest number since 1987. Twenty eight of the 97 (29%) men who seroconverted between January 1989 and December 1991 were aged less than 25. The proportion of men aged 15-19 who were found to be infected with HIV-1 at their first test increased from an average of 2.4% up to 1990 to 4.7% in the first nine months of 1991. The prevalence of HIV infection in men under 25 attending genitourinary medicine clinics in London was 17% compared with 7.8% outside London. CONCLUSION: Unsafe sexual behaviour and HIV transmissions have increased among homosexual men after a period of decline. Recent HIV transmissions may disproportionately affect younger men.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Increasing incidence of cryptococcosis in the United Kingdom.

The incidence of infection with Cryptococcus neoformans in the United Kingdom during the years between 1953 and 1981 is compared with that between 1982 and 1991. The patients were those from whom samples were submitted to the PHLS Mycological Reference Laboratory (MRL), or those in whom the disease was confirmed elsewhere in the United Kingdom and reported to PHLS Communicable Disease Surveillance Centre (CDSC). In all, 83 cases were identified between 1953 and 1981 and 322 between 1982 and 1991, 201 of which were known to be HIV-associated. The incidence of infection with Cryptococcus neoformans has increased four-fold in the last decade. It is an increasing cause of infection in immunosuppressed patients, most notably those with HIV infection. Currently, 4.0% patients with AIDS in the United Kingdom are known to have developed cryptococcosis.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Improved survival from diagnosis of AIDS in adult cases in the United Kingdom and bias due to reporting delays.

OBJECTIVE: To measure developments in survival patterns among United Kingdom adult AIDS cases. DESIGN: A follow-up survey of cases reported voluntarily to the national surveillance schemes was undertaken to obtain up-to-date information on vital status. METHODS: All reporting clinicians who had a current AIDS patient not known to have died whose AIDS-defining illness was diagnosed before the end of September 1990 were contacted. A total of 3984 cases were included in the analysis. RESULTS: An extra third of deaths other than those reported through routine channels were ascertained by follow-up. Median survival for patients diagnosed before and after the end of 1986 increased from 15 to 18 months for men who had sex with men presenting with Kaposi's sarcoma, from 10 to 19 months for other men who had sex with men and from 7 to 16 months for all others. Improvement in survival was greatest in the first 3 months. One-third of patients have been surviving 2 years or more. Factors observed with independent effects on improved survival are recent diagnosis, younger age and larger cumulative AIDS case load of reporting centre. HIV encephalopathy and other central nervous system symptoms may be associated with poorer survival. CONCLUSIONS: Survival patterns have been changing and generally improving. Average survival for very recent cohorts tends to be underestimated because longer survival has been observed in patients for whom there is a longer delay between AIDS diagnosis and report to the Communicable Disease Surveillance Centre. Information on mortality is improved by active follow-up.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Cement-within-cement revision hip arthroplasty.

We reviewed 19 revision hip arthroplasties in which the new femoral component had been recemented into the old, intact cement mantle. The mean time from the first operation to revision was 64 months and the average follow-up was 59 months. There were 7 excellent, 11 good, and one fair result. No femoral component had been revised for loosening and all the stems appeared radiographically stable. Complications included intraoperative perforation of the femur on two occasions and one dislocation. The use of the cement-within-cement technique requires that the old cement surface be dry and roughened to increase the surface area and that the cement be injected in the liquid phase to prevent lamination. The indications for this technique include a broken stem with an intact distal cement mantle, the removal of a femoral component for revision of a loose cup to improve exposure and/or increase offset, recurrent dislocation secondary to component malposition, and debonding of the femoral component within an intact cement mantle.

Adult↗
PubMed1993

The rationale for cemented total hip arthroplasty.

Long-term follow-up of early Charnley cemented THAs demonstrates excellent survival (Table 1). New techniques in cementing have improved the quality of the femoral cement fixation and have shown consistently good performance at 10-year follow-up. Noncemented designs have not yet demonstrated similar long-term results. Recent reports reveal osteolysis in noncemented prostheses, which is observed earlier than in cemented designs. This implies a greater role for polyethylene debris in the etiology of osteolysis. Polyethylene debris is produced not only at the articulation but also at the nonarticular metal-polyethylene interface in modular metal-backed acetabular components. This results in the production of additional plastic debris. Metal backing has not demonstrated any clinical improvement in the long-term performance of cemented acetabular components. Furthermore, it may be detrimental due to decreased polyethylene thickness, increased stress within the polyethylene, and an increased rate of polyethylene wear of both the articular and nonarticular surfaces. Multiple reports have demonstrated that titanium alloy is not an acceptable articulating surface because it has a poor resistance to abrasion. It can result in severe metallosis in the periarticular tissues, leading to progressive osteolysis and early failure of the arthroplasty. Caution is suggested in the widespread application of polymodular femoral components because the production of metallic debris may prove excessive. Cemented THA remains the gold standard by which other methods of fixation must be assessed. The enviable long-term results with early cementing techniques and the Charnley prosthesis will be difficult to match, even with developing technology.

Acetabulum↗
PubMed1992

Heterosexually acquired HIV-1 infection: cases reported in England, Wales and Northern Ireland, 1985 to 1991.

By the end of 1991, there had been 417 reports of AIDS and 1620 reports of HIV-1 infection in persons in England, Wales and Northern Ireland who probably acquired their infection through sexual intercourse between men and women. Between 1986 and 1991, the proportion of AIDS cases attributable to heterosexual transmission increased from 2% to 14% and of diagnosed HIV-1 infections from 4% to 23%. Reported HIV-1 infections inadequately reflect the extent of infection as only individuals choosing to be tested can be reported. HIV-1 infection acquired during heterosexual intercourse may be the result of transmission from partners who were infected by routes other than heterosexual transmission (first generation transmission) or of transmission from infected partners who were themselves infected through heterosexual intercourse (second generation transmission). Of the 417 cases in which AIDS was acquired through heterosexual intercourse, 42 (10%) were categorised as due to first generation transmission, 328 (79%) as second generation transmission--abroad, and 47 (11%) as second generation transmission--UK. Transmission categories could be allocated to 1438 of the 1620 reports of HIV infection: 17% were categorised as first generation, 74% as second generation--abroad, and 9% as second generation--UK. Heterosexual transmission of HIV infection is increasing, both in individuals acquiring their infection abroad as well as those who become infected in the United Kingdom.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Second generation heterosexual transmission of HIV-1 infection.

Reports of 217 HIV-1 infected persons have been investigated. Initially, 122 were described as having no identified risk of HIV infection and 95 were described as probably infected through heterosexual intercourse. The sexual partners of 34 of these 95 cases were reported as having acquired their infection heterosexually in the UK but information on the risk status of the sexual partners of the remaining 61 cases was lacking. Telephone follow-up through microbiologists and clinicians resulted in the recategorisation of 132 cases. Interviews were conducted with 22 HIV infected heterosexuals without a major risk for HIV infection, either in themselves or their sexual partners, and who had no evidence of heterosexual exposure outside the UK. Interviews confirmed the categorisation of 15 cases (9 male, 6 female) as due to second generation HIV-1 infection ie, infection acquired through heterosexual intercourse in the UK with a partner who also became infected through heterosexual intercourse. A possible chain of transmission is described involving three of these 15 cases.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Evaluation of the painful total hip arthroplasty.

Total hip arthroplasty is a common technique for the surgical management of degenerative hip disease. Because of the increasing number of patients and the variety of prostheses and fixation modalities available to the surgeon, the evaluation of the patient with a painful arthroplasty has become an increasingly complex endeavor. The growing number of patients who undergo multiple revision surgeries further complicates the evaluation of the painful arthroplasty. Other complicating factors include the lack of absolute sensitivity and specificity of the variety of diagnostic techniques and the difficulty of differentiating pain caused by septic verses aseptic loosening. This report reviews the recent literature concerning the evaluation of the painful total hip arthroplasty and provides a clinical rationale for the assessment of the painful total hip arthroplasty.

Diagnosis, Differential↗
PubMed1992

The normal glenohumeral relationships. An anatomical study of one hundred and forty shoulders.

We measured the dimensions of the humeral and glenoid articular surfaces in 140 shoulders that were representative of a given population of patients, and also evaluated several glenohumeral relationships. Ninety-six measurements were made in the shoulders of cadavera and forty-four, on magnetic resonance-imaging studies of living patients. Eighty-five per cent of the humeral measurements fell within eight fixed combinations of the radius of curvature and the thickness of the humeral head, in two-millimeter increments. The average radius of curvature of the humeral head in the coronal plane was 24 +/- 2.1 millimeters (range, nineteen to twenty-eight millimeters). The average thickness of the humeral head was 19 +/- 2.4 millimeters (range, fifteen to twenty-four millimeters). There was a wide variability in the size of the humeral head and a direct correlation between the differences in size and the heights in both men and women. The humeral articular surface was spherical in the center; however, the peripheral radius was two millimeters less in the axial plane than in the coronal plane. Thus, the peripheral contour of the articular surface was elliptical (ratio, 0.92). The radius of curvature of the glenoid, measured in the coronal plane, was an average of 2.3 +/- 0.2 millimeters greater than that of the humeral head. The average dimensions of the glenoid in the superior-inferior and anterior-posterior (lower half) directions were 39 +/- 3.5 millimeters (range, thirty to forty-eight millimeters) and 29 +/- 3.2 millimeters (range, twenty-one to thirty-five millimeters). The anterior-posterior dimension of the glenoid was pear-shaped, the lower half being larger than the top half. The ratio of the lower half to the top half was 1:0.80 +/- 0.01. There was a strong linear correlation between the lateral humeral offset and the size of the humeral head (radius of curvature and thickness). The average lateral humeral offset was 56 +/- 5.7 millimeters (range, forty-three to sixty-seven millimeters). The superior most point on the humeral articular surface was an average of 8 +/- 3.2 millimeters (range, three to twenty millimeters) cephalad to the top of the greater tuberosity. Our data show that reconstruction of the lateral humeral offset is important in optimization of the moment arm of the deltoid and rotator cuff and of the normal tension of the soft tissue after prosthetic reconstruction.

Adult↗