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Biomedical subjects

K Porter

Publications and source records attributed to K Porter.

At least 37 records · Page 2Linked to original sources
PubMed1996

A gene (RPGR) with homology to the RCC1 guanine nucleotide exchange factor is mutated in X-linked retinitis pigmentosa (RP3).

X-linked retinitis pigmentosa (xlRP) is a severe progressive retinal degeneration which affects about 1 in 25,000 of the population. The most common form of xlRP, RP3, has been localised to the interval between CYBB and OTC in Xp21.1 by linkage analysis and deletion mapping. Identification of microdeletions within this region has now led to the positional cloning of a gene, RPGR, that spans 60 kg of genomic DNA and is ubiquitously expressed. The predicted 90 kD protein contains in its N-terminal half a tandem repeat structure highly similar to RCC1 (regulator of chromosome condensation), suggesting an interaction with a small GTPase. The C-terminal half contains a domain, rich in acidic residues, and ends in a potential isoprenylation anchorage site. The two intragenic deletions, two nonsense and three missense mutations within conserved domains provide evidence that RPGR (retinitis pigmentosa GTPase regulator) is the RP3 gene.

Amino Acid Sequence↗
PubMed1996

AIDS defining diseases in the UK: the impact of PCP prophylaxis and twelve years of change.

We examined all reports of adult AIDS cases made to the 2 national surveillance centres in the UK for changes in AIDS defining conditions between January 1982 and September 1994. Differences and changes among persons diagnosed since January 1988 who had and had not been aware of their HIV infection prior to their AIDS diagnosis were of particular interest. Pneumocystis carinii pneumonia (PCP) is the AIDS defining disease most often reported at the initial AIDS diagnosis. Its proportion of all AIDS cases has increased significantly between January 1982 and December 1987 and decreased markedly thereafter. Since January 1988 a significant decrease in the proportion of cases diagnosed with cryptosporidial infection was also observed while increases were observed in the proportion of cases diagnosed with: HIV wasting (chi(1)(2) = 5.56) PML (chi(1)(2) = 19.47), mycobacterium avium complex (chi(1)(2) = 35.76) and pulmonary tuberculosis (chi(1)(2) = 144.0). For cases diagnosed between January 1988 and September 1994, PCP was more likely to be diagnosed in patients previously unaware of their HIV infection (P < 0.01) as was extrapulmonary TB (P < 0.01). In contrast, the following diseases were more likely to be diagnosed in patients already aware of their HIV infection prior to the diagnosis of AIDS: oesophageal candidiasis (P < 0.001), HIV wasting (P = 0.07), mycobacterium avium complex (P = 0.0001), cytomegalovirus disease (P < 0.001), HIV encephalopathy (P = 0.0009) and cryptosporidial infection (P = 0.02). Prophylaxis and anti-retroviral therapy appear to have had a significant impact on the temporal changes of the most frequently diagnosed AIDS diseases. While PCP prophylaxis has substantially reduced the likelihood of a PCP diagnosis at AIDS, the corresponding increase in other opportunistic infections suggests that there may be a need for improved prophylaxis for these conditions.

AIDS Dementia Complex↗
PubMed1995

Boron-containing oligodeoxyribonucleotide 14mer duplexes: enzymatic synthesis and melting studies.

A set of three 14mer oligodeoxyribonucleotides of sequence d(5'-CTATGGCCTCAG*CT-3'/3'-GATACCGGAGTCGA-5') containing G* variants either as 2'-deoxyguanosine phosphate (unmodified), N7-cyanoborane 2'-deoxyguanosine phosphate (base-modified) or 2'-deoxyguanosine boranophosphate (backbone-modified) were synthesized by template-directed primer extension. Both the N7-cyanoborane 2'-deoxyguanosine triphosphate and 2'-deoxyguanosine alpha-boranotriphosphate nucleotides are good substrates for Sequenase. We infer that a single Sp boranophosphate linkage (which has a stereochemistry equivalent to the corresponding Rp thiophosphate analog) is formed in the backbone-modified 14mer. Thermally induced helix-coil transitions were monitored for the hybridized duplexes using UV and circular dichroism (CD) spectroscopy. The CD spectra of the two types of boron-modified hybrids closely resemble the unmodified parent duplex, forming B-type helices in 150 mM NaCl, 1 mM EDTA, 10 mM phosphate, pH 7.4, buffer. UV melting results indicate that both hybrids have stabilities comparable with the parent duplex as measured by Tm or delta G degree 25. These studies indicate that singly modified base- or backbone-boronated DNA are good analogs of normal DNA.

Base Sequence↗
PubMed1995

Response to news that an obstetrician/gynaecologist has AIDS.

This paper summarises the response of a district health authority, in March 1993, to the diagnosis of AIDS in a consultant obstetrician/gynaecologist. A helpline was established, facilities to test for HIV antibody were arranged, and patients upon whom the infected doctor had performed surgical procedures in the preceding 10 years were identified from local records. Letters were sent to patients who did not contact the helpline, with advice and the offer of HIV antibody testing. A total of 4594 National Health Service and private patients of the obstetrician/gynaecologist were identified, 1206 of whom (26%) were tested for HIV antibody. A further patient, who had other identified risks for HIV infection, had been known to be positive for anti-HIV since 1992. An additional 475 people who had not been treated by the doctor asked to be tested as a result of the publicity given to the incident. The estimated cost to the health authority of this patient notification exercise was 150,100 pounds.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Characterization and transfusion of in vitro cultivated hematopoietic progenitor cells.

Our study is to show the safety of transfusion and the number, phenotype, and proliferative potential of in vitro cultivated autologous hematopoietic peripheral blood progenitor/stem cells (PBPCs). An in vitro long-term liquid culture using PBPC suspension from consenting patients with metastatic breast cancer was established. The medium was supplemented with a variety of hematopoietic growth factors. The mononuclear cells (MNCs), their viability, CD34+ subsets, clonogenic cells, and neutrophil function were measured prior to, during, and after liquid culture for 14 days. The total cell number increased during incubation in vitro from 2.5 x 10(8) to 5 x 10(9). The clonogenic and CD34+ cells increased during the first week 6- and 3.5-fold, respectively, and were almost undetectable after 2 weeks. Maturation into the myeloid cell series was demonstrated by standard cytology and increase of CD33+ and CD38+ cell numbers. On average, 1.5 x 10(9) cells were transfused to consenting patients with metastatic breast cancer after high-dose chemotherapy and PBPC transplantation at nadir of WBC < or = 0.1/nL. One hour later, the mean WBC was measurable at 0.3/nL. Subsequently, WBC counts dropped to 0.2/nL and 0.1/nL at 6 and 24 h post transfusion. No side effects and complications were observed. In summary, an in vitro expansion can produce a > or = 20-fold increase of maturing PBPCs for an effective and safe autologous transfusion. This unique approach, when refined, could lead to a safer post-transplant period and a decrease of complications due to neutropenic fever.

Adult↗
PubMed1994

Views of dental patients about the education and practice of dentists.

The opinions of 253 adult U.K. dental patients were sought as to the scope of dental education. Most appreciated this was a university education and that it exceeded 3 yr. Nearly one half believed that apprenticeship was involved and one quarter believed that postgraduate experience in hospital was mandatory. Few acknowledged the wide breadth of training and a majority would consult a physician rather than a dentist regarding problems such as oral ulceration.

Adolescent↗
PubMed1993

Health care workers and HIV: surveillance of occupationally acquired infection in the United Kingdom.

In the period 1985-1992, 176 significant occupational exposures to HIV were reported to the PHLS Communicable Disease Surveillance Centre. The outcome at three months post exposure was reported for 134 (76%) incidents. Ninety-nine of these involved percutaneous exposure to HIV-infected blood or serum; two resulted in seroconversion, one following the use of zidovudine post exposure. Under-reporting of significant exposures may have been considerable. However, the observed transmission rate, of 2%, is not inconsistent with other estimates. Two other documented seroconversions after occupational exposure have been reported, making a total of four health care workers known to have acquired HIV infection after occupational exposure in the UK. Another six UK health care workers have possible occupationally acquired HIV infections. Five of these probably became infected while working in adverse conditions in Africa; the other while working with HIV-infected patients in the United States and Europe. A summary of current good practice of post exposure management is provided. Practitioners providing post exposure care are asked to contribute to the national surveillance scheme. Initial reporting of significant occupational exposures, and of serological outcome at a minimum of six months post exposure, should be regarded as integral to satisfactory post exposure management.

Blood-Borne Pathogens↗
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

Class I and II HLA antigens in British patients with oral lichen planus.

The frequencies of human leukocyte antigens--HLA-A, HLA-B, HLA-C, HLA-DR, and HLA-DQ1--were determined in a group of 40 white British patients with oral lichen planus and compared with those of healthy controls. Alterations in the frequencies of several HLA antigens were noted. In particular, an increase in HLA-Bw57 and a decrease in the frequency of HLA-DQ1 were seen in the group with lichen planus. When different clinical subgroups of lichen planus were compared with the control group, significant changes were also noted in the frequencies of HLA antigens. This suggests that lichen planus may represent a heterogeneity of diseases and that HLA-Bw57 may predispose a person to lichen planus whereas HLA-DQ1 may be associated with resistance to it.

Adult↗
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

Changing incidence of Pneumocystis carinii pneumonia as initial AIDS defining disease in the United Kingdom.

OBJECTIVE: To determine whether the incidence of Pneumocystis carinii pneumonia (PCP) as the initial AIDS-defining disease in adult AIDS cases in the United Kingdom is changing over time and to examine factors likely to affect it. SUBJECTS AND METHODS: A total of 4419 adult AIDS cases diagnosed in the United Kingdom between January 1989 and December 1992 were analysed using logistic regression models. An initial diagnosis of PCP was used as the outcome variable and the possible effects of age, sex, exposure category, ethnic group, half year of diagnosis, geographical area of report, and whether or not the individuals had been aware of their HIV infection when AIDS was diagnosed was examined. RESULTS: A significant decline in PCP incidence was observed over time. Incidence of PCP declined among subjects who had been aware of their infection for 9 months or more before AIDS diagnosis. There was no evidence of a change in PCP incidence over time for subjects who had had HIV infection diagnosed 3 or less months before an AIDS diagnosis. Individuals who had been aware of their HIV infection, individuals reported from the Thames health regions, and non-white patients were much less likely to have had a diagnosis of PCP. CONCLUSIONS: The decline of PCP incidence in subjects aware of their serostatus, and therefore more likely to have received primary prophylaxis, suggests that they may have benefited from this treatment. Our findings provide evidence of the value of an early HIV diagnosis and confirmation of the beneficial effects of primary prophylaxis for PCP.

AIDS-Related Opportunistic Infections↗
PubMed1992

An analysis of conditions presenting to a dental hospital emergency clinic.

A retrospective analysis of 1,000 consecutive patients was undertaken to determine the frequency and types of common dental problems presenting to the Emergency and Oral Medicine Clinic at Bristol Dental Hospital. The results show that most attenders presented with problems readily manageable by dental practitioners, but providers of emergency dental services should be aware that rare, but serious, conditions can occur. Information presented in this paper should be incorporated into the design of undergraduate curricula and emergency dental services.

Dental Service, Hospital↗