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Biomedical subjects

T F Smith

Publications and source records attributed to T F Smith.

At least 271 records · Page 15Linked to original sources
PubMed1982

Comparison of two methods used to prepare smears of mouse lung tissue for detection of Pneumocystis carinii.

The laboratory diagnosis of Pneumocystis carinii pneumonia in humans includes the identification of cysts in stained lung tissue impression smears. By using a mouse model, we compared the number of cysts in lung tissue impression smears with those contained in a concentrate of homogenized lung tissue. Eleven C3H/HEN mice developed P. carinii infection after corticosteroid injections, a low protein (8%) diet, and tetracycline administered in drinking water. Impression smears were prepared with freshly bisected lung tissue. Smears of concentrates were prepared with sediment from centrifuged lung tissue homogenates. All smears were made in duplicate, stained with toluidine blue O or methenamine silver, coded, randomized, and examined. The concentrate preparations contained more cysts per microscopic field than the impression preparations (P less than 0.01). Concentrates prepared by grinding with a mortar and pestle contained more cysts than concentrates prepared by blending with a Stomacher (P less than 0.05). Cysts were detected equally well with either the toluidine blue O or silver stain (not significant). Lung tissue concentrates were superior to lung tissue impressions for detecting P. carinii cysts in mice. Use of lung tissue concentrates should be considered for the diagnosis of human P. carinii infection.

Animals↗
PubMed1982

Evaluation of the anticomplement immunofluorescence test for detection of antibody to varicella-zoster virus.

The anticomplement immunofluorescence (ACIF) test was compared with complement fixation and fluorescent antibody to membrane antigen procedures for the detection of antibody to varicella-zoster virus. All of 50 sera from pregnant women contained antibody measured by ACIF (titer, greater than or equal to 1:10); only 27 (54%) were positive by complement fixation (P less than 0.01). For 16 paired sera obtained before and after varicella-zoster virus infection and tested by ACIF and fluorescent antibody to membrane antigen, the result agreed in 27 determinations (sensitivity, 94%; specificity, 81%). Of 99 sera submitted for routine determinations of immune status to the virus, 89 showed comparable results for both tests (sensitivity, 92.5%; specificity, 88%). The ACIF test offers a specific and sensitive alternative to the fluorescent antibody to membrane antigen procedure for the detection of antibody to varicella-zoster virus. In addition, the ACIF test is rapid, easy to perform, and uses commercially available reagents.

Antibodies, Viral↗
PubMed1982

Histamine in nasal secretions and serum may be elevated during viral respiratory tract infections.

This study investigated histamine concentration in nasal secretions from children who had viral respiratory tract infection. It demonstrated that (1) there may be appreciable histamine in nasal secretions during viral respiratory tract infection; (2) concentration of histamine in serum may be elevated at the same time; and (3) children with past medical or family history of atopy had more histamine in nasal secretions during viral infections than did nonatopic children.

Bronchiolitis, Viral↗
PubMed1981

Comparative biosequence metrics.

The sequence alignment algorithms of Needleman and Wunsch (1970) and Sellers (1974) are compared. Although the former maximizes similarity and the latter minimizes differences, the two procedures are proven to be equivalent. The equivalence relations necessary for each procedure to give the same result are: 1, the weight assigned to gaps in the Sellers algorithm exceed that in the Needleman-Wunsch algorithm by exactly half the length of the gap times the maximum match value; and 2, for any pair of aligned elements, the degree of similarity assigned by the Needleman-Wunsch algorithm plus the degree of dissimilarity assigned by the Sellers algorithm equal a constant. The utility of the algorithms is independent of the nature of the elements in the sequence and could include anything from geological sequence to the amino acid sequences of proteins. Examples are provided using known nucleotide sequences, one of which shows two sequences to be analogous rather than homologous.

Amino Acid Sequence↗
PubMed1981

Evaluation of the FIAX test for the detection of antibodies to herpes simplex virus and cytomegalovirus.

Laboratory Branch Complement Fixation and FIAX (fluorescence immunoassay) were compared for the detection of antibodies to herpes simplex virus and cytomegalovirus in human sera. Of 68 sera with no antibodies to herpes simplex virus by complement fixation, one specimen was positive by FIAX (specificity, 98.6%). Of 75 sera with complement fixation antibodies, five specimens were negative by the FIAX procedure (sensitivity, 93.8%). Comparable results were obtained with the cytomegalovirus antigen, in that only three of 76 sera with complement fixation antibodies gave positive FIAX results (specificity, 96.2%). Only three of 74 sera with complement fixation antibodies to cytomegalovirus were not detected by FIAX (sensitivity, 96.1%). FIAX titers increased with complement fixation levels in 39 of 42 serum pairs (93%) with herpes simplex virus antibody and in 44 of 47 sera (94%) containing antibodies to cytomegalovirus, but the increments were not necessarily linear. The FIAX test for measuring antibody to herpes simplex virus and cytomegalovirus antigens is specific, sensitive, rapid (three to four hours per 100 specimens), and reproducible.

Antibodies, Viral↗
PubMed1981

Marfan's syndrome with 47,XXX genotype and possible immunologic abnormality.

A 2-year-old girl with Marfan's syndrome also had recurrent episodes of upper respiratory infection, otitis media, tonsillitis, and asthma. Chromosomal study revealed the karyotype 47,XXX. Immunologic evaluation showed lack of delayed hypersensitivity skin test response despite previous exposure. The coincidence of Marfan's syndrome and either XXX or immunologic dysfunction has not been reported previously. This case clearly illustrates that more than one abnormality may occur in a single patient.

Child, Preschool↗
PubMed1981

Activation of complement by cells infected with respiratory syncytial virus.

The ability of respiratory syncytial virus (RSV)-infected HE(p)-2 cells in culture to activate complement was investigated. After incubation of cells with various complement sources and buffer, binding of C3b to surfaces of infected cells was demonstrated by immunofluorescence with a double-staining technique. Nonsyncytial and syncytial (i.e., fused, multinucleated) cells were separately enumerated. Also, lysis of RSV-infected cells was assessed by lactic dehydrogenase release. In this system only RSV-infected cells stained for C3b, and they did so only after incubation with functionally active complement. Blocking of classical pathway activation with ethylenediaminetetraacetic acid diminished the number of infected nonsyncytial cells positively stained for C3b, but had no effect on staining of syncytial cells. Blocking of alternative pathway activation with either zymosan incubation or heat treatment decreased the number of both syncytial and nonsyncytial cells stained for C3b. Decreasing immunoglobulin concentration of the serum used as the complement source also decreased numbers of both cell types stained for C3b. Eliminating specific anti-RSV antibody diminished numbers of both cell types stained for C3b, but staining was not eliminated. Lastly, incubation with functionally active complement markedly increased lactic dehydrogenase release from infected cells. This study demonstrated that RSV-infected nonsyncytial and syncytial cells are able to activate complement by both classical and alternative pathways. Activation of complement by syncytial cells appears to be less dependent on the classical pathway than is activation by nonsyncytial cells, and activation by syncytial cells may require immunoglobulin but not specific antibody. These experiments suggest the possibility of complement activation during respiratory tract infection by RSV. Implications of this are discussed.

Antibodies, Viral↗
PubMed1981

Recovery of viruses from three transport media incorporated into culturettes.

A double-blind prospective study was carried out to compare the rates of recovery of viruses from the upper respiratory tracts of children, using three different transport media. Stuart's, Hanks', and Leibovitz-Emory (LEM) media were packaged in the ampules of Culturettes and labeled in code by the manufacturer. Three swabs (one each from culturettes containing different media) were inserted simultaneously into the oropharynx or pressed onto unroofed dermal lesions, transported to the laboratory, and inoculated into MRC (Medical Research Council)-5 and primary monkey kidney-cell cultures. Eighty isolates were obtained from 200 specimens (40%) collected during all four seasons of the year. Parainfluenza virus, enterovirus, adenovirus, and herpes simplex virus accounted for 79% of the isolates. Of 80 isolates, 72 (90%) were recovered in Hanks', 64 (80%) in Stuart's, and 63 (79%) in LEM. The differences were not significant.

Child↗
PubMed1980

Occam's razor.

Explore the source record for details and available documents.

Animals↗
PubMed1980

Decreased ventilation response to hypoxia in children with asthma.

We measured the ventilation and inspiratory muscle activity responses to hypoxia and hypercapnia in 18 children with asthma. Ventilation was less efficient in the asthmatic children in that more inspiratory muscle activity per liter of ventilation was required than in normal children. Asthmatic and healthy children had similar ventilation responses to hypercapnia; at all levels of end-tidal Pco2, the inspiratory muscle activity was greater in those with asthma. However, during progressive isocapnic hypoxia, asthmatic patients did not increase their inspiratory muscle activity at a rate greater than normal. Thus, because of inefficient ventilation, they had significantly decreased ventilatory responses to hypoxia. Neither ventilation nor inspiratory muscle activity response to hypoxia was correlated with duration of illness or with the degree of airways obstruction present. These results demonstrate that children with chronic asthma have decreased hypoxic responsiveness and suggest that neither long-term airways obstruction nor intermittent hypoxia associated with asthma is necessary to diminish hypoxic response in asthmatic patients. An asthmatic child with depressed hypoxic responsiveness may be at increased risk of hypoxic complications or respiratory failure during acute asthma.

Airway Obstruction↗
PubMed1980

In vitro antimicrobial activity of rosoxacin against Neisseria gonorrhoeae, Chlamydia trachomatis, and Ureaplasma urealyticum.

The antimicrobial activity of rosoxacin, a new quinoline antibacterial compound, was determined against the causative organisms of three sexually transmitted diseases. Rosoxacin demonstrated a high degree of activity against Neisseria gonorrhoeae clinical isolates, with the minimal inhibitory concentrations for 50% of these being 0.03 microgram/ml. The corresponding minimal inhibitory concentrations for penicillin, ampicillin, tetracycline, and spectinomycin were 0.25 U/ml, 0.125 microgram/ml, 0.25 microgram/ml, and 16 microgram/ml, respectively. Eleven strains of Chlamydia trachomatis were inhibited by 5 microgram of rosoxacin per ml, and each of seven Ureaplasma urealyticum strains was inhibited by 2 to 8 microgram of rosoxacin per ml. The results of these susceptibility studies, coupled with those of an earlier evaluation of the pharmacokinetics of rosoxacin, provide support for extending or undertaking clinical evaluations of this compound against infections with N. gonorrhoeae, C. trachomatis, and U. urealyticum.

4-Quinolones↗
PubMed1980

Etiology and outcome in 42 children with acute nonbacterial meningoencephalitis.

In a prospective study of 42 cases of childhood meningoencephalitis occurring in 1974 and 1975, a diagnosis of an infectious agent was made in 30 (71%). California virus infections were most common; they were serious illnesses but had few sequelae. Benign illnesses with enteroviruses were also common. Miscellaneous and unknown agents accounted for the most seriously ill patients and for both deaths. Persistent neurologic deficits were unusual. Headaches, malaise, and changes in behavior were common but transient.

Acute Disease↗
PubMed1980

Case reports. Intrauterine echovirus type II infection.

The case described herein represents the first laboratory-confirmed case indicating intrauterine infection due to echovirus type II. The virus was recovered from the vagina of the mother and from the blood from the umbilical cord and nasopharynx of an apathetic newborn (all cultures were taken within 60 minutes of birth in the delivery room) with a generalized maculopapular exanthem. When the infant was 15 days of age, results of all laboratory tests and physical examinations were normal.

Adult↗
PubMed1980

Arterial oxygen desaturation during sleep in children with asthma and its relation to airway obstruction and ventilatory drive.

The possibility that arterial oxygen saturation (SaO2) decreases during sleep in children with chronic bronchial asthma was investigated. The relationship between decreases in sleep SaO2 and airflow obstruction and ventilatory drives, as characterized by ventilatory and inspiratory muscle activity responses to hypoxia and hypercapnia was also examined. Sixteen asthmatics on suboptimal bronchodilator therapy and ten healthy children were studied. Both maximum decrease in SaO2 and number of desaturations (decrease in SaO2 greater than or equal to 4%) per hour during sleep were greater in the asthmatics than in the control subjects. Both maximum decrease in SaO2 and number of desaturations per hour asleep were correlated with change in FEV1 and FEF25%-75% over the sleep period. Changes in SaO2 were not related to awake measurements of ventilatory drive. Eight of the asthmatics also were studied when on a more optimal medication regimen. On this program they had less airflow obstruction before and after sleep, and the number and extent of decreases in SaO2 were not different from those of the control subjects. We conclude: (1) decreases in SaO2 occurred during sleep in suboptimally treated asthmatic children; (2) SaO2 changes during sleep were related to the amount of air-flow obstruction that developed during sleep; (3) SaO2 changes during sleep were not related to ventilatory drive measured during wakefulness; and (4) a good therapeutic regimen eliminated abnormal amounts of sleep hypoxemia by improving airflow limitation. However, as the results of this study indicate, when their pulmonary status is unstable, asthmatic children may develop clinically significant hypoxemia during sleep.

Airway Obstruction↗