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Biomedical subjects

T F Smith

Publications and source records attributed to T F Smith.

At least 163 records · Page 9Linked to original sources
PubMed1989

Rapid shell vial culture and tissue histology compared with serology for the rapid diagnosis of cytomegalovirus infection in liver transplantation.

Sixty-six patients who had undergone 78 liver transplantations, with no detectable cytomegalovirus (CMV) infection before transplantation, were studied to assess the value of CMV serology compared with the rapid detection of the virus in shell vial cell cultures or histology for the diagnosis of (1) the first evidence of infection, (2) symptomatic disease, and (3) asymptomatic infection. Of 28 evaluable patients, shell vial cell culture assay and histologic findings provided the first evidence of CMV infection earlier in 22 (79%) or at the same time as the serologic response in 5 (18%). Serologic results yielded the first indication of CMV infection in only 1 of these 28 patients (3%). Of 17 evaluable transplantations in 15 patients in whom symptomatic invasive disease developed, shell vial culture or histology provided a laboratory diagnosis of CMV infection earlier or at the same time as serologic responses in 16 (94%). Similarly, shell vial culture or histology provided evidence of CMV infection in 10 of 11 patients (91%) who had asymptomatic CMV infection and remained asymptomatic. Urine surveillance cultures yielded the first evidence of CMV infection in 14 of 19 patients who initially had an asymptomatic infection, of which 6 became symptomatic. Culturing of the blood with use of the rapid shell vial technique showed that viremia preceded CMV organ involvement in 7 of 10 patients. We recommend culture by the shell vial assay as the most rapid and sensitive method of determining CMV infection in liver transplant patients.

Cytomegalovirus Infections↗
PubMed1989

Incidence, distribution, and outcome of episodes of infection in 100 orthotopic liver transplantations.

Of 83 patients who underwent 100 orthotopic liver transplantations, 53 had a single transplant procedure and at least 6 months of follow-up. In this main study group of 53 patients, major infections developed in 28 (53%) (a mean of 1.8 major episodes per infected patient). Of 51 major infections, 27 were bacterial, 19 were viral, 3 were protozoan, and 2 were fungal. Of the 27 bacterial infections, 22 (81%) occurred in the first 2 months after transplantation. Of the 40 bacterial isolates in the 27 bacterial infections, gram-positive aerobic bacteria were isolated in 26 (65%), anaerobic bacteria in 8 (20%), and aerobic gram-negative bacteria in 6 (15%). Only 1 of 16 bacteremic episodes was due to a gram-negative aerobic bacterium. Cytomegalovirus (CMV) infection occurred in 30 of the 53 patients (57%) and was symptomatic and invasive in 18. CMV infection was diagnosed a mean of 26 days after transplantation. Infections due to Pneumocystis carinii occurred later (2 to 3 months after transplantation). Death from infection occurred in 4 of the 53 patients (8%). In the group of 16 patients with two or more liver transplantations, fungal infection occurred in 2 and CMV infection in 13. In all 16 patients who underwent more than one liver transplantation, a major infection developed. The observations made in the main study group were consistent with findings in 13 patients with one liver transplantation but less than 6 months of follow-up. Infection is a major complication after liver transplantation, generally occurring in the first 2 months. Our observations suggest that the use of selective bowel decontamination may be associated with a relatively lower incidence of gram-negative aerobic bacterial infections.

Bacterial Infections↗
PubMed1989

New analytical tool for analysis of splice site sequence determinants.

A new analytical method has been used to examine the set of 40 exon/intron boundaries within the rat embryonic myosin heavy chain (MHCemb) gene. It has also been applied to an additional set of 850 splice sequences selected from GenBank. Strong evidence is obtained for the involvement of 3' ends but not 5' ends of exon sequences in splice site recognition. It can be determined that signal sequences of 5' intron ends concentrate near the splice borders, while the distributions of the 3' intron ends have a diffuse character. The possibility of re-interpreting some known features, in terms of the absence of certain elements rather than the presence of elements forming sequence determinants, is discussed. The analysis undertaken enabled us to work out a more detailed set of recognition sequence requirements for the splicing of nuclear pre-mRNA. In addition to requirements which have already been established we suggest the following: the 'AG-absence' in the immediate 3' terminal intron sequences; and a minimal match between a particular sequence and the known exon/intron consensus sequence of 5' splice junctions.

Animals↗
PubMed1989

Cytomegalovirus hepatitis in liver transplantation: prospective analysis of 93 consecutive orthotopic liver transplantations.

Ninety-three consecutive orthotopic liver transplantations in 78 patients were followed prospectively to study the incidence of cytomegalovirus (CMV) hepatitis. CMV hepatitis occurred in 13 (17%). The diagnosis was established by both histology and culture in 5, only by histology in 6, and only by culture in 2. All 13 patients had CMV viruria and 9 had viremia at diagnosis. CMV hepatitis developed in 64% of CMV-seronegative (pretransplantation) patients who received a liver from a CMV-seropositive donor, compared with 3% or 6% of CMV-seropositive patients who received a liver from a CMV-seronegative or CMV-seropositive donor, respectively (P less than .001). CMV hepatitis was not a cause of fulminant or irreversible liver dysfunction in any of the 13 cases. Ganciclovir was administered to 6 of the 13 patients and was associated with clinical and virologic cure in 5. CMV hepatitis was self-limited in patients not treated with ganciclovir (illness less severe). The presence of inclusions within the liver tissue correlated with active disease.

Age Factors↗
PubMed1989

Laboratory characterization of a swine influenza virus isolated from a fatal case of human influenza.

A swine influenza virus-like type A (H1N1) virus, designated A/Wisconsin/3523/88, was isolated in September 1988 from a Wisconsin woman who had died with primary viral pneumonia. Antigenic analyses with hemagglutinin-specific monoclonal antibodies and postinfection ferret serum indicated that the hemagglutinin of A/Wisconsin/3523/88 was antigenically closely related to viruses currently circulating in swine. Genetic analysis of the A/Wisconsin/3523/88 virus by RNA fingerprinting and partial RNA sequence analysis of seven of the eight segments indicated that the genome of the human isolate was similar to that of enzootic swine viruses. These laboratory data supported the epidemiologic findings that this human infection occurred by transmission of an enzootic swine influenza virus and that the virus showed no major genetic changes potentially related to increased pathogenesis.

Adult↗
PubMed1989

Multisite evaluation of a monoclonal antibody reagent (Syva) for rapid diagnosis of cytomegalovirus in the shell vial assay.

A pre-cytopathic effect (CPE) monoclonal antibody reagent (Syva Co., Palo Alto, Calif.) was evaluated in four laboratories for the rapid detection of cytomegalovirus (CMV) in shell vial cell cultures at 16 to 24 h and 40 to 48 h postinoculation. Results were compared with those obtained by inoculation of the specimen into conventional tube cell cultures that were examined for the presence of typical CMV CPE and subsequently tested by reaction with the monoclonal antibody reagent in an indirect immunofluorescence test. Of 937 specimens, CMV was positive in 184 (20%). CMV was detected twice as frequently in shell vials only (n = 29) as in conventional tube cell cultures (n = 14). Pre-CPE shell vial assay was 91% sensitive (range, 84 to 98%) and 96% specific (range, 93 to 98%) compared with the detection of CPE in conventional tube cell cultures. Overall, 137 of 166 (83%) and 143 of 166 (86%) of the CMV strains were detected at 16 to 24 h and 40 to 48 h postinoculation, respectively. The Syva reagent produced sensitive and specific results for the rapid detection of CMV infection in shell vial cell cultures and reliably confirmed the presence of the virus as detected by CPE in conventional tube cell cultures.

Antibodies, Monoclonal↗
PubMed1989

Effect of age of shell vial monolayers on detection of cytomegalovirus from urine specimens.

The effect of age of MRC-5 cell monolayers in shell vials on the detection of cytomegalovirus (CMV) from urine was evaluated. When the AD169 strain of CMV was used, 8-day-old monolayers had a higher mean count of fluorescent foci than 15-day-old monolayers did (5.78 versus 2.86) (P less than 0.02) and were more frequently positive (21 of 23 shell vials versus 14 of 22 shell vials) (P less than 0.04). Commercial shell vials used for clinical specimens were evaluated in groups of 8- to 11-, 12- to 15-, and 8- to 15-day-old monolayers. When compared with laboratory-prepared shell vials ranging in age from 3 to 9 days, commercial shell vials had a lower number of fluorescent foci in all groups (P less than 0.03, P less than 0.0001, and P less than 0.0001, respectively), the 12- to 15- and 8- to 15-day-old groups were less frequently positive (P less than or equal to 0.02 and P less than 0.02, respectively), and all three groups were more susceptible to the toxic effects of urine (P less than 0.0001, P less than 0.01, and P less than 0.0001, respectively). For all 191 specimens cultured (8- to 15-day-old group), one or both monolayers were destroyed in 60 (31.4%) specimens compared with 9 (4.7%) specimens toxic to laboratory-prepared shell vials (P less than 0.0001). Both the decreased sensitivity of older MRC-5 cells and the increased sensitivity to the toxic effects of urine made commercial shell vial less sensitive than laboratory-prepared shell vials for the detection of CMV.

Cell Line↗
PubMed1989

Identification of new protein kinase-related genes in three herpesviruses, herpes simplex virus, varicella-zoster virus, and Epstein-Barr virus.

By using amino acid sequence patterns (motifs) diagnostic of conserved regions within the catalytic domains of protein kinases, homologous open reading frames of three herpesviruses were identified as protein kinase-related genes. The three sequences, herpes simplex virus gene UL13, varicella-zoster virus gene 47, and Epstein-Barr virus gene BGLF4, resemble serine/threonine kinases rather than tyrosine kinases.

Amino Acid Sequence↗
PubMed1989

Pneumocystis carinii pneumonia. Differences in lung parasite number and inflammation in patients with and without AIDS.

Pneumocystis carinii pneumonia has emerged as a significant cause of morbidity and mortality in immunocompromised patients with and without AIDS. To determine differences in P. carinii pneumonia in patients with and without AIDS, the P. carinii parasite numbers, lung inflammatory cell populations, gas exchange, and survival were assessed in a series of 75 consecutive patients with P. carinii pneumonia. Bronchoalveolar lavage was used to quantify the parasite and inflammatory cell numbers in these patients. The data from this study indicate: (1) patients with P. carinii pneumonia and AIDS have significantly greater numbers of P. carinii per ml of lavage compared to other immunocompromised patients with P. carinii pneumonia (p less than 0.0001); (2) patients with P. carinii pneumonia and AIDS also have significantly fewer neutrophils recovered in the lavage compared to other immunocompromised patients with P. carinii pneumonia (p = 0.0001); (3) patients with AIDS and P. carinii pneumonia have higher arterial oxygen tensions than those patients with P. carinii pneumonia in conditions other than AIDS (p = 0.008); and (4) increased lavage neutrophils (rather than parasite number) correlate with poorer oxygenation and poorer patient survival (p = 0.01). This investigation demonstrates substantial differences in lung inflammation and parasite number during P. carinii pneumonia in patients with and without AIDS. The data further suggest that lung inflammation contributes substantially to respiratory impairment in patients with P. carinii pneumonia.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Chronic fatigue syndrome and the diagnostic utility of antibody to Epstein-Barr virus early antigen.

Antibody to Epstein-Barr virus (EBV) early antigen has been said to be the most specific indicator of symptomatic chronic EBV infection. We studied the clinical utility of this serologic test in the evaluation of patients with chronic fatigue. Thirty patients with chronic fatigue and highly elevated titers of antibody to early antigen (greater than or equal to 1:160) were compared with 30 age- and sex-matched controls with no antibody to early antigen. There were no significant differences noted between patients and controls at the initial evaluation (symptoms, physical examination, laboratory data). Follow-up information, available for 15 matched pairs, showed no differences in outcome between patients and controls. We conclude that the antibody to EBV early antigen is not helpful in the clinical evaluation of patients with chronic fatigue.

Antibodies, Viral↗
PubMed1988

In vitro release of histamine from murine mast cells by block co-polymers composed of polyoxyethylene and polyoxypropylene.

A series of block co-polymers composed of polyoxyethylene and polyoxypropylene were investigated for their ability to induce in vitro activation of mouse mast cells. We found that six of these co-polymers could cause histamine release from mouse mast cells in vitro. At low concentrations, the most efficacious co-polymer, T130R2, caused rapid and extensive concentration-dependent release of histamine from mouse mast cells. The release process was not cytotoxic; it required metabolic energy and was not accompanied by release of lactate dehydrogenase. Optimal release of histamine was dependent on both calcium and sodium ions in the extracellular medium. The degree of in vitro histamine release correlated with in vivo inflammation and in vitro ionophore activity. We believe that this represents the first report of the activation of mediator-containing cells by an ionophore selective for monovalent cations. These copolymers may therefore represent new reagents for investigations of cellular excitation.

Adjuvants, Immunologic↗
PubMed1988

Histamine release from human basophils by synthetic block co-polymers composed of polyoxyethylene and polyoxypropylene and synergy with immunologic and non-immunologic stimuli.

Co-polymers composed of polyoxyethylene and polyoxypropylene have been shown previously to trigger histamine release from mouse peritoneal mast cells; this property quantitatively is directly related to the ionophorous ability of these compounds to cause a functional exchange of intracellular K+ for extracellular Na+ across the cell membrane. We investigated the effect of an inflammatory copolymer, T130R2, on human basophils. The data demonstrate that T130R2 can cause calcium-dependent histamine release from human basophils in vitro. Further, at concentrations that do not cause histamine release, this co-polymer markedly augments release by suboptimal concentrations of the lectin Con A or anti-IgE antibody and the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate but not the calcium ionophore A23187. Thus, these co-polymers induce mediator release from cells of both rodents and humans. In both instances it is likely that calcium-dependent cell triggering is the result of an influx of sodium ions with concomitant depolarization of the transmembrane potential. In common with the calcium ionophore A23187, the co-polymer T130R2 has the ability to synergize with stimuli which trigger the IgE receptor as well as those which directly activate the cellular calcium- and phospholipid-dependent protein kinase.

Adjuvants, Immunologic↗
PubMed1988

The phylogenetic history of immunodeficiency viruses.

Knowledge of the phylogenetic history of the human immunodeficiency viruses (HIV-1 and HIV-2) is important for our understanding of the epidemiology of AIDS, the disease caused by these viruses. Reconstruction of the evolutionary tree is hampered, however, by two problems. One is the high variation in nucleotide sequence between the known HIV isolates which can create formidable difficulties in identifying homologous genomic sites that may be used in a molecular phylogenetic reconstruction. Another impediment has been the lack of unequivocal time calibration points: there is only a sparse 'fossil record' for HIV and limited historical epidemiological data. We have largely overcome these difficulties by: (1) a thorough optimal-sequence alignment analysis; (2) the inclusion of sequences of an early (1976) HIV-1 isolate, a recent (1986) HIV-2 isolate and two simian immunodeficiency viruses (SIV) along with five other HIV-1 isolates; and (3) the reconstruction of a minimum-length evolutionary tree based on the envelope-gene variable positions. We conclude that HIV-1 may have evolved from its common ancestor with HIV-2 as recently as 40 years ago.

Animals↗