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Biomedical subjects

T F Smith

Publications and source records attributed to T F Smith.

At least 235 records · Page 13Linked to original sources
PubMed1985

Detection of viral and chlamydial antigens in open-lung biopsy specimens.

The recovery of viruses and Chlamydia trachomatis from cell cultures and the detection of their antigens in impression smears prepared from open-lung biopsy (OLB) specimens from immunocompromised adults were compared. Touch impression smears were prepared on three slides, each containing eight wells. OLB tissue was homogenized (Stomacher) and inoculated into MRC-5, primary monkey kidney, and McCoy cell cultures. The direct and indirect immunofluorescence (IF) tests were used to detect antigens to the following organisms: herpes simplex virus, adenovirus, parainfluenza types 1 and 3, respiratory syncytial virus, cytomegalovirus (CMV), Chlamydia trachomatis, influenza types A and B, and varicella-zoster virus. Of 105 OLB specimens, 21 viral isolates (20%) were recovered in cell culture; 20 were CMV and one was an influenza virus type A (H3N2). Both culture and IF results were positive with 12 specimens, but in nine instances a virus was isolated and IF was negative or eight times culture results did not yield the organism but IF test results were positive. Chlamydia trachomatis was never isolated or detected by IF. The authors recommend that for optimal detection of CMV from OLB specimens a new rapid centrifugation-enhanced cell culture system be used in preference, or in conjunction with a preliminary IF screen of impression smears for CMV detection.

Adult↗
PubMed1985

Codon usage in the vertebrate hemoglobins and its implications.

A study of codon usage in vertebrate hemoglobins revealed an evolutionary trend toward elevated numbers of CpG codon boundary pairs in mammalian hemoglobin alpha genes. Selection for CpG codon boundaries countering the generally observed CpG suppression is strongly suggested by these data. These observations parallel recently published experimental results that indicate that constitutive expression of the human alpha-globin gene appears to be determined by regulatory information encoded within the structural gene. The possibility is raised that, in the absence of selection, CpG decay can be used to date the evolutionary origin of a mammalian alpha pseudogene from its active alpha gene.

Animals↗
PubMed1985

Detection and serotyping of herpes simplex virus in MRC-5 cells by use of centrifugation and monoclonal antibodies 16 h postinoculation.

Monoclonal antibodies (Syva Co., Palo Alto, Calif.) were used for the detection and serotyping of herpes simplex virus (HSV) isolates by immunofluorescence 16 h after inoculation of MRC-5 monolayers in 3.7-ml shell vials and after low-speed centrifugation. A total of 119 specimens were inoculated into conventional tube cell cultures and shell vials. Of 98 specimens inoculated on the same day of receipt in the laboratory (fresh specimens), all 23 (23.5%) HSV-positive specimens were identified by serotype in 16 h in shell vials by immunofluorescence, whereas only 8 of 23 HSV-positive specimens (34.8%) produced cytopathic effects in conventional tube cell cultures in this time period. Similarly, of 21 original specimen extracts previously determined to be culture positive for HSV (stored specimens), all were detected and serotyped by the immunofluorescence test with monoclonal antibodies 16 h postinoculation compared with the recognition of only 8 of these isolates (38.1%) by cytopathic effect that soon. This technique of centrifugal inoculation of HSV in shell vials containing MRC-5 cells permitted detection of this virus in all positive specimens with serotype determination within 16 h postinoculation.

Antibodies, Monoclonal↗
PubMed1985

Comparison of processing techniques for detection of Pneumocystis carinii cysts in open-lung biopsy specimens.

Methenamine silver stain was used to compare the number of cysts of Pneumocystis carinii contained in lung concentrate smears of homogenized lung tissue with the number in impression smears. Results were also compared with histopathological examination of methenamine silver-stained paraffin-embedded sections. Of slides from 23 preparations, a greater number of cysts were contained in concentrate smears than in impressions (P less than 0.001). In four preparations, cysts were noted in concentrate smears only. All concentrate smears were positive, whereas 11 of the 23 histopathological sections were negative (P less than 0.01). The ability to detect the cyst phase of P. carinii in lung tissue is enhanced by the use of concentrate smears.

Biopsy↗
PubMed1985

Comparison of standard tube and shell vial cell culture techniques for the detection of cytomegalovirus in clinical specimens.

A monoclonal antibody was used to detect an early antigen of cytomegalovirus (CMV) by fluorescence 16 h after inoculation of MRC-5 monolayers in 1-dram (ca. 3.7-ml) shell vials and low-speed centrifugation. Of 770 specimens (urine, blood, lung tissue, sputum) processed in shell vials, 124 (16%) were positive for the virus at 16 h postinfection. CMV was isolated in standard tube cell cultures (average time, 9 days) from only 88 specimens, but there were no instances (with the exception of 2 blood specimens) in which CMV was recovered from tube cultures but not from shell vials. Additional specimens from 18 patients were positive in the shell vial assay but negative in the conventional tube cell culture assay. Other specimens from 14 of the 18 patients yielded CMV in conventional tube cell cultures. Of the 4 patients from whom CMV was not recovered from other specimens by conventional tube cell culturing, all had evidence of recent CMV infections, as indicated by a fourfold or greater rise in antibody titer. The specificity of the shell vial assay for the detection of CMV is supported by assays of other specimens from the same patients yielding the virus or serological evidence indicating recent infections, the known enhancement of CMV detection after centrifugation of the shell vials, and the distinct and easily recognizable fluorescence confined to the nuclei of CMV-infected cells. Our data indicate that the shell vial cell culture assay for the detection of CMV is as specific as and more sensitive than conventional tube cell culturing for the diagnosis of CMV infections.

Antibodies, Monoclonal↗
PubMed1985

Open lung biopsy in immunocompromised patients.

From January 1978 through December 1980, ninety-five immunocompromised patients underwent diagnostic open lung biopsy (OLB) at the Mayo Clinic, Rochester, Minn. A specific causative diagnosis was made in 77 patients (81%); 12 patients (13%) had more than one specific causative diagnosis. Of the 77 patients with a specific causative diagnosis, 52 patients (68%) had infections, 19 patients (24%) had malignant pulmonary disease, 12 patients (15%) had cytotoxic lung disease, ten patients (13%) had interstitial fibrosis (not related to cytotoxins), and one patient (1%) had vasculitis. In 36 (47%) of the 77 patients with a specific causative diagnosis, the diagnosis was made, by frozen sections or stains, within three hours of OLB. In 35 additional patients (45%), the diagnosis was established within 24 hours. Twelve patients (13%) had minor complications of OLB; no deaths were attributed to the OLB procedure.

Adolescent↗
PubMed1985

Pedal dislocations. An overview.

Identification of the mechanism of injury is the hallmark of dislocation management. If the mechanism can be established by history, anatomic disruptions can be logically explained and identified. Conversely, the injury pattern clinically may help deduce the mechanism. Once the mechanism is established, either historically or clinically, relocation maneuvers can be planned and executed. A review of pedal dislocations has been presented with emphasis on anatomic relationships and mechanism of injury. These principles encompass diagnosis, treatment, and management. They must be understood to manage not only the acute emergency situation but the chronic disability of post-traumatic arthritis.

Ankle Injuries↗
PubMed1985

Cytomegalovirus infection in patients undergoing noncardiac surgical procedures.

A search for records for CMV infection following transfusion related to noncardiac and nontransplant operations and trauma disclosed nine instances with CMV seroconversion. One patient had received only a single unit of blood. The most prominent feature was fever with a characteristic spiking plateau pattern, which began approximately three weeks after blood transfusion. Splenomegaly and atypical lymphocytosis were less common. The results of hepatic function tests showed slight abnormalities. Associated splenectomy did not result in a more severe manifestation of the CMV infection. The late postoperative fever in these patients led to an extensive and costly investigation before determination of antibody titers to CMV and confirmation of seroconversion. When faced with the constellation of symptoms, including a delayed (two to three weeks) spiking plateau postoperative fever, abnormal results of hepatic function test and lymphocytosis in patients having received blood transfusion, the clinician must give serious consideration to the possibility of CMV infection.

Adolescent↗
PubMed1984

On the statistical significance of nucleic acid similarities.

When evaluating sequence similarities among nucleic acids by the usual methods, statistical significance is often found when the biological significance of the similarity is dubious. We demonstrate that the known statistical properties of nucleic acid sequences strongly affect the statistical distribution of similarity values when calculated by standard procedures. We propose a series of models which account for some of these known statistical properties. The utility of the method is demonstrated in evaluating high relative similarity scores in four specific cases in which there is little biological context by which to judge the similarities. In two of the cases we identify the statistical properties which are responsible for the apparent similarity. In the other two cases the statistical significance of the similarity persists even when the known statistical properties of sequences are modelled. For one of these cases biological significance is likely while the other case remains an enigma.

Base Sequence↗
PubMed1984

Algorithms for restriction map comparisons.

An algorithm is presented which compares two restriction maps, yielding a measure of distance between the maps and relating the maps by an alignment. This new algorithm finds the minimum weighted sum of genetic events required to convert one map into the other, where the genetic events are the appearance/disappearance of restriction sites and changes in the number of bases between restriction sites. The algorithm is illustrated by comparison of the beta-delta region of the globin gene cluster of four primate species. The results are in excellent agreement with known evolutionary relationships.

Animals↗
PubMed1984

Comparison of iodine- and fluorescein-labeled monoclonal antibodies for detection of Chlamydia trachomatis inclusions in cells grown in glass vials.

A fluorescein-labeled monoclonal antibody was compared with the iodine stain for the detection of chlamydial inclusions in McCoy cells grown on cover slips in glass vials. The remainder of the original specimen extracts in 2-sucrose phosphate transport medium from 100 specimens (50 male, urethra; 50 female, cervix), stored at -70 degrees C and previously determined to be culture positive for Chlamydia trachomatis by the iodine stain, were inoculated into vials containing monolayers of McCoy cells. Cover slips were coded and examined microscopically after 40 hr at 35 degrees C. The mean numbers of inclusions detected by iodine and by immunofluorescence were the same. One-half of the specimens had eight or fewer inclusions present. There was a trend indicating that less time was required for microscopic examination of cover slips for chlamydial inclusions with immunofluorescence than with the iodine-staining method. The tagged monoclonal antibody is a high-quality immunodiagnostic reagent for use in the immunofluorescence test; however, our data derived from stored specimen extracts indicate equivalence of detection of inclusions in the glass vial system compared to iodine.

Antibodies, Monoclonal↗
PubMed1984

IgG subclasses in nonallergic children with chronic chest symptoms.

Immunoglobulin and IgG subclass measurements were made on sera from 37 children thought to have asthma whose chronic chest symptoms were unexplained by allergy. There was a higher proportion of low or low-normal levels of IgG subclasses 1, 2, and 4 in these children than in normal children. Those who had low serum IgG values on initial measurement had a higher proportion of low or low-normal levels of IgG1, IgG2, and IgG4; those who had normal IgG values had a higher proportion of low or low-normal levels of IgG2 and IgG4. Thus a normal serum concentration of IgG did not exclude the possibility of an abnormal level of IgG2 or IgG4. Our experience suggests that abnormal levels of IgG subclasses might play an etiologic role in the chronic chest symptoms in some of these children.

Asthma↗
PubMed1984

The relationship between codon boundaries and multiple reading-frame preferences: coding organization of bacterial insertion sequences.

Theoretical considerations have shown that the five possible overlapping reading-frame configurations differ significantly in their coding flexibility and thus in their information content (Siegel and Fitch 1980; Smith and Waterman 1980). Contrary to expectation, the overlapping frame configuration allowing the greatest coding flexibility is rarely seen, whereas one of the most constraining is common. We point out here that this overlapping reading-frame paradox and an observed but unexplained preference in coding regions for a pyrimidine-purine at codon boundaries (Shepherd 1981; Jones and Kafatos 1982; Smith et al. 1983) are intimately linked. The codon boundary preference, which may be related to translation efficiency or accuracy, places constraints on the evolution of overlapping coding regions. These considerations may help identify actual coding regions in DNA sequences. We have analyzed five sequenced (enteric) bacterial insertion sequences for codon boundary incidences and reading-frame configurations and find that they are consistent with these proposed constraints.

Bacteria↗
PubMed1984

Evaluation of an enzyme-linked immunosorbent assay for the detection of herpes simplex virus antigen.

An enzyme-linked immunosorbent assay (ELISA) kit for herpes simplex virus developed by Ortho Diagnostic Systems, Inc., was evaluated. In phase I experiments, 263 clinical specimens from genital lesions were extracted into serum-free medium and then tested by ELISA for herpes simplex virus antigen. The results were compared with those obtained by conventional viral culture. Of 83 specimens, 65 were positive by ELISA (sensitivity, 78.3%). In phase II experiments, 249 clinical specimens were tested for herpes simplex virus antigen in direct specimen and in cell cultures (MRC-5 and rabbit kidney) incubated for 2, 4, and 7 days. Of 63 specimens, 40 were positive by ELISA in the direct specimen (sensitivity, 63.5%), and by 7 days incubation, 100% of the cultures positive by viral cell culture were also positive by ELISA. The ELISA was reproducible, and when both the direct detection and amplification culture were used, the sensitivity of ELISA paralleled the diagnosis of herpes simplex virus infections by viral cytopathic effect.

Antigens, Viral↗
PubMed1984

Rapid detection of cytomegalovirus in MRC-5 cells inoculated with urine specimens by using low-speed centrifugation and monoclonal antibody to an early antigen.

A commercially available monoclonal antibody directed against an early nuclear protein of cytomegalovirus was used with low-speed centrifugation for the rapid detection of this virus from urine specimens inoculated onto MRC-5 cells. A total of 19 of 162 (11.7%) urine specimens inoculated were positive by both immunofluorescence and peroxidase-antiperoxidase procedures (sensitivity, 100%), whereas only 18 of the samples produced cytopathic effects in conventional cell culture (specificity, 94.7%). All specimens were positive by immunofluorescence and peroxidase-antiperoxidase procedures at 36 h postinfection, whereas an average of 9 days was required for cytopathic effects to develop in cell cultures.

Adolescent↗
PubMed1984

Detection of Chlamydia trachomatis in genital specimens by the Chlamydiazyme test.

Cotton swabs were used to collect two specimens each from 416 patients (206 males, 210 females) attending a sexually transmitted disease clinic. The first swab was transported in Specimen Storage Reagent and extracted in Specimen Dilution Buffer for enzyme immunoassay by Chlamydiazyme (Abbott Laboratories); the second swab was extracted into 2SP and inoculated into McCoy cell cultures. In the first phase of the study (215 patients: 111 males, 114 females) enzyme immunoassay results were positive (optical density greater than or equal to 0.1) in 30 of 35 instances in which Chlamydia trachomatis was isolated (sensitivity, 86%). Of 18 false-positive enzyme immunoassay results, 15 (83%) were cervical swabs (specificity, 90%). In a phase II study, using a modified Chlamydiazyme kit, 201 patients were tested (95 males, 106 females). Of 41 chlamydial isolates, 8 were not detected by the Chlamydiazyme test (sensitivity, 81%). Only three positive Chlamydiazyme test results could not be confirmed by culture (specificity, 98%). Overall, Chlamydiazyme assay provided a rapid (4 h), sensitive, and specific assay for the detection of chlamydial antigens.

Antigens, Bacterial↗