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Biomedical subjects

J Jameson

Publications and source records attributed to J Jameson.

At least 19 recordsLinked to original sources
PubMed2003

Management of benign rectal strictures: a review of present therapeutic procedures.

PURPOSE: A significant benign stricture of the rectum is uncommon but can be a recalcitrant condition to treat. Case reports detailing a particular treatment option abound in the surgical literature. An overall précis of the different techniques available is presented, with a comparison of their relative strengths and weaknesses. METHODS: A literature search was undertaken from 1963 to the present day, using MEDLINE. Keywords were benign, strictures, and rectum. RESULTS: Balloon dilation is the most frequent intervention described in the literature. Repeated dilation with time often is required to achieve normal bowel function. Electrocautery resection or incision combined with dilation increases the success rate without increasing the complication rate. Transanal strictureplasty with mechanical staplers is reported as achieving the best success with the smallest complication rate; however, only a minority of strictures are suitable to be managed in this way, and therefore, the numbers treated are small. CONCLUSIONS: All of the techniques reviewed compared favorably with formal stricture resection in terms of success rate and complications.

Anastomosis, Surgical↗
PubMed2002

Risk factors for intestinal ischaemia in cardiac surgical patients.

OBJECTIVE: Mesenteric ischaemia is an uncommon (<1%) but serious complication of cardiac surgery associated with a mortality >50%. Predictors of this complication are not well defined, and diagnosis can be difficult and prompt surgical intervention can be lifesaving. METHODS AND RESULTS: In a retrospective case-note analysis from May 1994 through to May 2000, we identified mesenteric ischaemia in 39 of 5349 consecutive patients (0.07%) undergoing cardiac surgery with cardiopulmonary bypass. By logistic multivariate analysis, we have identified six possible predictors of intestinal ischaemia: duration of cross-clamp, use of significant inotropic support, intra-aortic balloon counterpulsation for low cardiac output, need for blood transfusions, triple vessel disease and peripheral vascular disease. In all patients a combination of four predictors were present. Patients who survived this complication had surgical intervention earlier (6.4+/-3.8 h) than those who did not (16.9+/-10 h). CONCLUSIONS: The diagnosis and prompt treatment of mesenteric ischaemia post cardiac surgery requires a high degree of awareness. These predictors may be useful in alerting medical staff to the possibility of gastro-intestinal ischaemic complications after cardiac surgery particularly that early surgical intervention reduces mortality.

Cardiac Surgical Procedures↗
PubMed1999

Partial agonist effect influences the CTL response to a heterologous dengue virus serotype.

Activation of dengue serotype-cross-reactive memory CTL during secondary dengue virus (DV) infection is thought to be important in the pathogenesis of dengue hemorrhagic fever. To model this effect, we studied the CTL responses to DV types 2 (D2V) and 3 (D3V) in PBMC from an individual previously infected with D3V. DV-specific CD8+ CTL from this donor recognized two HLA-B62-restricted epitopes on the NS3 protein, aa 71-79 (SVKKDLISY) and 235-243 (AMKGLPIRY). Both D3V-specific and D2V/D3V-cross-reactive CTL clones were detected for each epitope; all D2V-reactive CTL clones could lyse D2V-infected autologous cells. CTL responses to both epitopes were detected in bulk cultures stimulated with D3V, but PBMC stimulated with D2V recognized only the 235-243 epitope. IFN-gamma enzyme-linked immunospot assay showed that the D2V (71-79) peptide (DVKKDLISY) did not efficiently activate T cells. Analysis of a CTL clone suggests that the D2V (71-79) peptide acts as a partial agonist, able to sensitize target cells for lysis and inducing only minimal proliferation at high concentrations. These results suggest that variant peptide sequences present in the heterologous DV serotype can influence the CTL response in vivo during secondary DV infection.

Adult↗
PubMed1999

Augmentation of human influenza A virus-specific cytotoxic T lymphocyte memory by influenza vaccine and adjuvanted carriers (ISCOMS).

There is a need to improve the ability of subunit vaccines to induce CD8(+) CTL responses in humans, especially for vaccines used to prevent illness by organisms that undergo antigenic variation at their major neutralizing antibody sites, e.g., influenza A viruses and human immunodeficiency virus. Murine models have demonstrated the protective role of cross-reactive CTL against influenza A virus antigenic drift. We tested the ability of an adjuvanted carrier (Iscomatrix) to help human antigen-presenting cells present formalin-killed influenza vaccine to human CD8(+) CTL clones in vitro and in vaccinated humans. The results of a randomized, double-blind, controlled clinical study demonstrate that a single dose of a vaccine formulated into Iscom particles increased influenza A virus-specific CTL memory in 50-60% of recipients, compared to 5% of the recipients of the standard influenza vaccine.

Adolescent↗
PubMed1999

High-yield reassortant influenza vaccine production virus has a mutation at an HLA-A 2.1-restricted CD8+ CTL epitope on the NS1 protein.

Current influenza virus vaccines are prepared using high-yield reassortant virus strains obtained from a mixed infection of the new virus strain and a prototype high-yielding virus strain. The high-titered reassortant virus strain used as vaccine seed virus possesses the recent virus HA and NA and contains the internal genes from the high-growing prototype parent. We established a human CD8(+) cytotoxic T cell (CTL) line, 10-2C2, which recognizes an HLA-A2.1-restricted influenza A virus H1, H2, H3 cross-reactive T cell epitope on amino acids 122-130 of the NS1 protein, and unexpectedly we observed that there was decreased lysis of target cells infected with the A/Texas/36/91 (H1N1) vaccine virus strain compared to the lysis of target cells infected with the prototype A/PR/8/34 (H1N1) virus. RT-PCR results showed that the A/Texas vaccine virus strain contained a quasispecies. Approximately 50% of viral RNA of the NS1 gene had a nucleotide substitution that resulted in the N --> K amino acid change at the sixth position of the nonamer peptide. Current influenza vaccines are inactivated and do not contain the NS1 protein; however, future influenza vaccines may include live attenuated vaccines and with this mutation a live virus would fail to induce a CD8(+) CTL response to this epitope in individuals with HLA-A2.1, a very common allele, and potentially have reduced efficacy.

Base Sequence↗
PubMed1999

Human CD8+ and CD4+ T lymphocyte memory to influenza A viruses of swine and avian species.

Recently, an avian influenza A virus (A/Hong Kong/156/97, H5N1) was isolated from a young child who had a fatal influenza illness. All eight RNA segments were of avian origin. The H5 hemagglutinin is not recognized by neutralizing Abs present in humans as a result of infection with the human H1, H2, or H3 subtypes of influenza A viruses. Subsequently, five other deaths and several more human infections in Hong Kong were associated with this avian-derived virus. We investigated whether influenza A-specific human CD8+ and CD4+ T lymphocytes would recognize epitopes on influenza A virus strains derived from swine or avian species, including the 1997 H5N1 Hong Kong virus strains. Our results demonstrate that adults living in an urban area of the U.S. possess influenza A cross-serotype reactive CD8+ and CD4+ CTL that recognize multiple epitopes on influenza A viruses of other species. Bulk culture cytotoxicity was demonstrated against avian and human influenza A viruses. Enzyme-linked immunospot assays detected precursor CTL specific for both human CTL epitopes and the corresponding A/HK/97 viral sequences. We hypothesize that these cross-reactive CTL might provide partial protection to humans against novel influenza A virus strains introduced into humans from other species.

Animals↗
PubMed1998

Human cytotoxic T-lymphocyte repertoire to influenza A viruses.

The murine CD8(+) cytotoxic-T-lymphocyte (CTL) repertoire appears to be quite limited in response to influenza A viruses. The CTL responses to influenza A virus in humans were examined to determine if the CTL repertoire is also very limited. Bulk cultures revealed that a number of virus proteins were recognized in CTL assays. CTL lines were isolated from three donors for detailed study and found to be specific for epitopes on numerous influenza A viral proteins. Eight distinct CD8(+) CTL lines were isolated from donor 1. The proteins recognized by these cell lines included the nucleoprotein (NP), matrix protein (M1), nonstructural protein 1 (NS1), polymerases (PB1 and PB2), and hemagglutinin (HA). Two CD4(+) cell lines, one specific for neuraminidase (NA) and the other specific for M1, were also characterized. These CTL results were confirmed by precursor frequency analysis of peptide-specific gamma interferon-producing cells detected by ELISPOT. The epitopes recognized by 6 of these 10 cell lines have not been previously described; 8 of the 10 cell lines were cross-reactive to subtype H1N1, H2N2, and H3N2 viruses, 1 cell line was cross-reactive to subtypes H1N1 and H2N2, and 1 cell line was subtype H1N1 specific. A broad CTL repertoire was detected in the two other donors, and cell lines specific for the NP, NA, HA, M1, NS1, and M2 viral proteins were isolated. These findings indicate that the human memory CTL response to influenza A virus is broadly directed to epitopes on a wide variety of proteins, unlike the limited response observed following infection of mice.

Adult↗
PubMed1998

Assessment of human CD4+ and CD8+ T lymphocyte responses in experimental viral vaccine studies.

The traditional in vitro correlate of immunological protection is the induction by a vaccine of neutralizing antibodies against the virus. It was formerly assumed that protection induced by a vaccine was solely due to neutralizing antibodies. Neutralizing antibodies are potent in the prevention of certain diseases, but virus-specific CD4+ T helper cells aid in the proliferation of specific antigen-triggered B cells to make antibodies. CD8+ T cells are responsible for eliminating virus-infected cells during viral illness, and may act as a second line of defence by becoming activated and eliminating any cells that become infected despite the presence of neutralizing antibodies, for example because of a large challenge dose or antigenic variation at the antibody combining sites. We will briefly review our approaches for measuring human virus-specific CD4+ and CD8+ T cell responses to experimental vaccines. It is critically important to have sensitive, quality controlled assays, including positive controls. There are many potential variables in human T cell assays and pitfalls, which usually result in negative CTL results. Uninterpretable data are to be expected unless adequate preliminary testing has been done to establish sensitive, specific and controlled human antigen specific CD4+ and CD8+ T cell assays.

B-Lymphocytes↗
PubMed1995

The impact of a pharmacotherapy consultation on the cost and outcome of medical therapy.

BACKGROUND: One important task for physicians is to optimize their patients' medication regimen. Involvement of clinical pharmacists who have specific training in drug regimen design has been associated with improved patient outcomes for specific medical conditions, eg, hypertension and anticoagulation. This prospective, randomized trial investigated whether a single consultation by a clinical pharmacist with high-risk patients and their primary physicians would result in improved prescribing outcomes. METHODS: Patients at risk for medication-related problems were identified and randomized to receive a pharmacotherapy consultation (consult group) or usual medical care (control group). Outcomes, including the number of drugs, number of doses per day, cost of medications, and patient reports of adverse effects, were recorded at baseline and at 6 months following the intervention. RESULTS: Fifty-six subjects were evaluable: 29 in the control group, and 27 in the consult group. Six months after the consultation, the number of drugs, the number of doses, and the 6-month drug costs all decreased in the consult group and increased in the control group; the net difference was 1.1 drugs (P = .004), 2.15 doses per day (P = .007), $586 per year (P = .008). The side effects score improved by 1.8 points more in the consult group compared with the control group (P = NS). Similarly, the prescribing convenience score in the consult group improved by 1.4 points more than that of the control group (P = NS). CONCLUSIONS: This study demonstrates several important benefits of integration of a clinical pharmacist into a primary care setting, including improvement in cost and simplification of the medication regimen with no reduction in quality of care.

Ambulatory Care↗
PubMed1986

Functional assessment of nursing home patients. Reliability and relevance.

Functional assessment of patients for resource allocation or staffing requires a higher level of interrater reliability than functional assessment in normal clinical settings. Although many functional assessment instruments are available, interrater reliability of these items has frequently not been reported. An assessment instrument based on the Long Term Care Minimum Data Set format was used for 290 patients in six wards in two Veterans Administration nursing homes. Each patient was assessed independently by two nurse caregivers to obtain reliability information. Different reliability measures yielded differing evaluations of the reliability of the instrument. Absolute agreement rates combined with Kendall's tau-b were most useful in deciding on the reliability of items in the instrument.

Activities of Daily Living↗
PubMed1982

Study of HLA alloantigens of the Navajo Indians of North America. II. HLA-A, B, C, DR and other genetic markers.

This report presents the antigen frequencies for HLA-A, B, C, DR, immunoglobulin, and red blood cell systems for the Navajo Indians of North America. HLA-A-B,B-C, and B-DR haplotype frequencies and significant delta values are given. These data are compared with similar data for other American Indians and major non-Indian ethnic groups. Very restricted HLA polymorphism is unique for the Navajo as well as American Indians in general and this feature has important implications with regard to disease association and transplantation.

Chromosome Mapping↗
PubMed1980

Positive pressure respiratory assist for wheelchair-mobile persons.

A compact, lightweight, battery-powered respiratory has been developed that fits under a wheelchair lapboard. The device eliminates the need for a mouthpiece, tracheal tube or similar interface. Its operation is based on pressurizing the viscera to compress the lungs and force exhalation. The system has been used continuously for over 9 months for as long as 9 hours/day.

Humans↗
PubMed1978

The effects of outpatient psychiatric utilization on the costs of providing third-party coverage.

Although previous studies conducted in prepaid group practice settings have indicated that the cost of providing coverage for outpatient psychotherapy may be offset by lower utilization of medical/surgical services among those who receive the benefit, no such studies have been conducted in a fee-for-service setting, nor have actual before and after claims costs been compared. This study establishes a methodology for using routinely collected Blue Cross claims data to show how the acquisition and use of a given benefit affects total utilization patterns and the overall costs of providing third-party coverage. The use and cost of outpatient psychiatric coverage in one subscriber group is the particular application given to this methodology in this report. Blue Cross claims records of 136 subjects who utilized outpatient psychiatric benefits over a 48-month period were analyzed. Results indicate that overall medical/surgical utilization is reduced for that subgroup who used the outpatient psychotherapy benefit and that average costs dropped by $9.41, from $16.47 per patient per month before outpatient psychotherapy to $7.06 after contact, with costs being adjusted to reflect parity with the base year. Factors other than psychiatric intervention which may have brought about this cost reduction as well as policy implications of these results are discussed.

Ambulatory Care↗