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Biomedical subjects

C P Conlon

Publications and source records attributed to C P Conlon.

At least 19 recordsLinked to original sources
PubMed2003

Immunization of patients with bleeding disorders.

The immunization of patients with bleeding disorders differs from that of the normal population with respect to the risk of haematoma formation at the vaccination site and the unusual infective risks associated with the potential, and past, exposure to blood products. Most vaccinations can be given subcutaneously and this should be the preferred route. All routine childhood vaccinations should be given at the appropriate time. All patients with bleeding disorders should be vaccinated against hepatitis A and B. HIV positive patients should receive annual influenza vaccinations and should avoid the oral polio, oral typhoid, BCG and yellow fever vaccines.

Adolescent↗
PubMed2001

Rapid detection of Mycobacterium tuberculosis infection by enumeration of antigen-specific T cells.

There is no reliable means of detecting latent M. tuberculosis infection, and even in patients with active tuberculosis, infection is often unconfirmed. We hypothesized that M. tuberculosis antigen-specific T cells might reliably indicate infection. We enumerated peripheral blood-derived interferon gamma (IFN-gamma)-secreting T cells responding to epitopes from ESAT-6, an antigen that is highly specific for M. tuberculosis complex but absent from BCG, in four groups of individuals. Forty-five of 47 patients with bacteriologically confirmed tuberculosis had ESAT-6-specific IFN-gamma-secreting T cells, compared with four of 47 patients with nontuberculous illnesses, indicating that these T cells are an accurate marker of M. tuberculosis infection. This assay thus has a sensitivity of 96% (95% confidence interval [CI] 92-100) for detecting M. tuberculosis infection in this patient population. By comparison, of the 26 patients with tuberculosis who had a diagnostic tuberculin skin test (TST), only 18 (69%) were positive (p = 0.003). In addition, 22 of 26 (85%) TST-positive exposed household contacts had ESAT-6-specific T cells, whereas zero of 26 unexposed BCG-vaccinated subjects responded. This approach enables rapid detection of M. tuberculosis infection in patients with active tuberculosis and in exposed asymptomatic individuals at high risk of latent infection; it also successfully distinguishes between M. tuberculosis infection and BCG vaccination. This capability may facilitate tuberculosis control in nonendemic regions.

Adolescent↗
PubMed2000

Travel and the immunocompromised host.

Increasing opportunities for travel and advances in medicine mean that immunocompromised patients may venture to potentially risky parts of the world. This article examines the risks faced by such travellers. Some limitations of standard travel vaccines are discussed and suggestions are made as to how best to advise such travellers.

Antineoplastic Agents↗
PubMed1999

Rapid death of adoptively transferred T cells in acquired immunodeficiency syndrome.

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) probably play the major role in controlling HIV replication. However, the value of adoptive transfer of HIV-specific CTL expanded in vitro to HIV+ patients has been limited: this contrasts with the success of CTL therapy in treating or preventing Epstein-Barr virus and cytomegalovirus disease after bone marrow transplantation (BMT). We investigated the fate of expanded HIV-specific CTL clones in vivo following adoptive transfer to a patient with acquired immunodeficiency syndrome (AIDS). Two autologous CTL clones specific for HIV Gag and Pol were expanded to large numbers (>10(9)) in vitro and infused into an HIV-infected patient whose viral load was rising despite antiretroviral therapy. The fate of one clone was monitored by staining peripheral blood mononuclear cells (PBMCs) with T-cell receptor-specific tetrameric major histocompatibility complex (MHC)-peptide complexes. Although the CTL transfer was well tolerated, there were no significant changes in CD4 and CD8 lymphocyte counts and virus load. By tracking an infused clone using soluble MHC-peptide complexes, we show that cells bearing the Gag-specific T-cell receptors were rapidly eliminated within hours of infusion through apoptosis. Thus, the failure of adoptively transferred HIV-specific CTL to reduce virus load in AIDS may be due to rapid apoptosis of the infused cells, triggered by a number of potential mechanisms. Further trials of adoptive transfer of CTL should take into account the susceptibility of infused cells to in vivo apoptosis.

Adoptive Transfer↗
PubMed1999

Acute pulmonary schistosomiasis in travelers returning from Lake Malawi, sub-Saharan Africa.

We describe four cases of acute schistosomiasis presenting to the Infectious Diseases Unit of John Radcliffe Hospital (Oxford, England) during a 2-month period in autumn 1997. All four patients had swum in Lake Malawi, a freshwater lake in sub-Saharan Africa that is associated with Schistosoma haematobium and, less commonly, Schistosoma mansoni infections. All four patients had a severe acute illness and had prominent pulmonary involvement, both clinically and radiologically. This represents a change in the recognized pattern of presentation and could possibly reflect a new parasite variant in the lake.

Acute Disease↗
PubMed1999

Pyoderma gangrenosum. A diagnosis not to be missed.

We describe a case of pyoderma gangrenosum which presented with severe wound breakdown after elective hip replacement. The patient was treated successfully with minimal wound debridement and steroids. This diagnosis should always be considered when confronted with an enlarging painful skin lesion which does not grow organisms when cultured and fails to respond to antibiotic therapy, especially if there are similar lesions in other sites. In patients who have a past history of pyoderma gangrenosum, prophylactic steroids may be indicated at the time of surgery or may be required early in the postoperative period.

Aged↗
PubMed1998

Disseminated Penicillium marneffei infection presenting as a right upper lobe mass in an HIV positive patient.

A 35 year old HIV positive patient from Hong Kong presented with a fever, cough and a skin rash in association with a lung mass, all of which were due to disseminated Penicillium marneffei infection. He made a good response to antifungal therapy. The lung mass is a previously undescribed pulmonary manifestation of disseminated Penicillium marneffei infection. Infections with this fungus should be suspected in any patient with HIV and respiratory symptoms who has visited southeast Asia.

AIDS-Related Opportunistic Infections↗
PubMed1996

Psittacosis associated with bilateral 4th cranial nerve palsies.

We report a 55-year-old man who presented with a moderately severe community acquired pneumonia due to Chlamydia psittaci, probably acquired from budgerigars. One of his presenting symptoms was diplopia, secondary to bilateral 4th cranial nerve palsies, which persisted for some months. The literature on neurological complications of pneumonia is reviewed.

Chlamydophila psittaci↗
PubMed1996

Safe intravenous antibiotic therapy at home: experience of a UK based programme.

Outpatient i.v. antibiotic therapy is well developed in the United States, largely because of pressures from third-party payers to reduce costs of medical care. We have developed an outpatient i.v. antibiotic programme in Oxford, that has evolved from a desire to provide high quality i.v. therapy to AIDS patients with cytomegalovirus retinitis. We describe the rationale of the service and report on our first two years' experience. We treated 67 consecutive patients (eight with HIV infection) at home with i.v. antibiotics. This resulted in a saving of 2275 hospital days for those patients without HIV infection. HIV positive patients received 69 months of home i.v. therapy. Minor intravascular catheter complications occurred in only five patients (7.5%). The only serious complications were three episodes of catheter-related sepsis (4.5%), all occurring in AIDS patients who had lines in for more than six months. We have shown that home i.v. antibiotic therapy can be delivered safely to patients with a wide variety of infectious problems using the existing network of community nurses in the National Health Service. Essential components to the programme include a multidisciplinary team working between the hospital and community and a written shared care protocol. Such a programme can result in reduced lengths of hospital stay and patient, community nurse and physician satisfaction.

Anti-Bacterial Agents↗
PubMed1994

Heterosexual transmission of human immunodeficiency virus type 1 variants associated with zidovudine resistance.

During zidovudine therapy, human immunodeficiency virus type 1 (HIV-1) acquires a distinctive set of mutations that diminish the sensitivity of the virus to this drug in vitro. An AIDS patient is described who, while being treated with zidovudine, transmitted HIV-1 bearing a drug resistance mutation to a young woman who had never received zidovudine treatment. DNA sequencing of HIV-1 proviruses confirmed that these 2 persons shared HIV genetic variants, including a mutation at codon 70 in the reverse transcriptase gene associated with reduced in vitro sensitivity to zidovudine. This mutation persisted in the woman > 1 year in the absence of antiretroviral therapy. HIV-1 with genetic markers of zidovudine resistance can be transmitted heterosexually, but it is uncertain whether dissemination of drug-resistant virus will substantially reduce the usefulness of this drug.

Adult↗
PubMed1993

The immunocompromised traveller.

Increasing numbers of immunocompromised people are travelling abroad to areas where the risks of some infections are increased. HIV positive people respond reasonably well to most vaccines when asymptomatic but response is less predictable when symptomatic disease is present. Generally, live vaccines should be avoided in all stages of HIV disease. Patients with anatomic or functional asplenia are at particular risk of severe sepsis due to encapsulated bacteria and from malaria. They should be immunised against the pneumococcus, meningococcus, and haemophilus and should avoid travel to areas where the probability of malaria transmission is high. Patients receiving cancer chemotherapy or transplant recipients on long-term immunosuppression should avoid live virus vaccines but may benefit from bacterial polysaccharide vaccines such as the pneumococcal vaccine. All patients with potentially impaired immunity should be assessed on an individual basis in terms of the risks and benefits involved in travel and available prophylactic measures. Immunisations useful in their native regions can be reviewed at the same time. Such travellers should carry a physician's letter and contact address in case of medical problems encountered abroad.

Aged↗