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Biomedical subjects

R Mann

Publications and source records attributed to R Mann.

At least 145 records · Page 8Linked to original sources
PubMed1980

Frameshift suppression in Saccharomyces cerevisiae. III. Isolation and genetic properties of group III suppressors.

Suppressors of ICR-induced mutations that exhibit behavior similar to bacterial frameshift suppressors have been identified in the yeast Saccharomyces cerevisiae. The yeast suppressors have been divided into two groups. Previous evidence indicated that suppressors of one group (Group II: SUF1, SUF3, SUF4, SUF5 and SUF6) represent mutations in the structural genes for glycyl-tRNA's. Suppressors of the other group (Group III: SUF2 and SUF7) were less well characterized. Although they suppressed some ICR-revertible mutations, they failed to suppress Group II frameshift mutations. This communication provides a more thorough characterization of the Group III suppressors and describes the isolation and properties of four new suppressors in that group (SUF8, SUF9, SUF10 and suf11).--In our original study, Group III suppressors were isolated as revertants of the Group III mutations his4-712 and his4-713. All suppressors obtained as ICR-induced revertants of these mutations mapped at the SUF2 locus near the centromere of chromosome III. Suppressors mapping at other loci were obtained in this study by analyzing spontaneous and UV-induced revertants of the Group III mutations. SUF2 and SUF10 suppress both Group III his4 mutations, whereas SUF7, SUF8, SUF9 and suf11 suppress his4-713, but not his4-712. All of the suppressors except suf11 are dominant in diploids homozygous for his4-713. The suppressors fail to suppress representative UAA, UAG and UGA nonsense mutations.--SUF9 is linked to the centromere of chromosome VI, and SUF10 is linked to the centromere of chromosome XIV. A triploid mapping procedure was used to determine the chromosome locations of SUF7 and SUF8. Subsequent standard crosses revealed linkage of SUF7 to cdc5 on chromosome Xiii and linkage of SUF8 to cdc12 and pet3 on chromosome VIII.

Chromosome Mapping↗
PubMed1979

The nasopharyngeal culture in acute otitis media. A reappraisal of its usefulness.

Simultaneous cultures of the nasopharynx and middle ear exudate (obtained by tympanocentesis) were obtained from 225 children (mean age, 34 months; median age, 41 months) with suppurative otitis media. A 72% prediction rate for middle ear pathogens was obtained by examining the nasopharyngeal cultures after the strict observance of two essential prerequisites: (1) the nasopharyngeal culture was immediately plated on appropriate solid agar and (2) a semiquantitative method for bacterial enumeration was employed in the reading of the nasopharyngeal culture plates. The technique was most valuable where 2+ (greater than 25% up to 50% of total number of colonies was a single pathogen) or greater of a single pathogen was recovered from the nasopharynx. In only one instance, the semiquantitative nasopharyngeal culture incorrectly predicted the middle ear pathogen if one was recovered. Quantitative nasopharyngeal cultures were particularly useful in predicting the presence of ampicillin-resistant Haemophilus influenzae and group A streptococci as causative agents in otitis media.

Acute Disease↗
PubMed1979

Preselection of alarms in a hybrid system for screening of cervical cancer.

In this report, a preselection of alarms in a system for automated screening of cervical cancer based on depositing the cell sample linearly as a "cell trace" on a tape and analyzing it at different decision levels with increasing complexity, and preliminary results on analyzing cervical material with this system are discussed. The "cell trace" is analyzed with the slit-scan technique. Six parameters are computed: 1) cellular diameter; 2) nuclear diameter; 3) nuclear fluorescence (acriflavin-Feulgen) as nuclear DNA; 4) cellular fluorescence; 5) nuclear to cytoplasm ratio (N/C ratio); and 6) nuclear density. At present, only nuclear fluorescence is used to define a decision boundary between normal and potentially atypical cells. Under this criteria the slit-scan analysis leaves 5% of the events in a sample that must be rechecked at a second decision level in normal cell samples. A further reduction is expected when several slit-scan parameters are used at the first decision step. All events declared suspicious will be investigated in more detail by a two dimensional image analyzing system where the fluorescence image is generated by a laser scanning system. Results obtained in preliminary experiments are discussed in this paper.

Computers↗
PubMed1978

Size estimation in paranoid and nonparanoid schizophrenics.

Fifteen paranoid and 15 nonparanoid schizophrenics and 15 normal controls were administered a size estimation task which featured two administrations of nonthematic standard stimuli. The standard stimuli were presented under three conditions of background stimuli: a) surrounded by four smaller stimuli of the same kind; b) surrounded by four larger stimuli of the same kind; c) presented without background stimuli. Standard stimuli were presented at exposure times of 33 and 4000 milliseconds. On the first administration, nonparanoid schizophrenics were found to overestimate size relative to paranoidschizophrenics with normal controls intermediate in performance between the paranoid schizophrenics and nonparanoid schizophrenics, particularly on longer stimulus exposure times. The groups did not differ on the second administration. This replication of the results of earlier investigations suggest that the repeated administration of size estimation procedures in which the effects of sequence and thematic content stimuli were inextricably confounded may have contributed to recent conflicting findings in the size estimation literature. Contrary to predictions generated by Cromwell's stimulus redundancy formation, the paranoid schizophrenics were not more affected by the size of the background stimuli than the nonparanoid schizophrenics.

Adult↗
PubMed1977

[Degradation of aflatoxin b1 by various microorganisms (author's transl)].

The degradation of aflatoxin B1 by various representatives of bacteria, yeasts and moulds in growing and resting cultures was investigated. We found that growing cultures of Corynebacterium rubrum degraded the added aflatoxin nearly quantitatively. -- Growing cultures of anascosporogenous yeasts degraded most of aflatoxin B1 while no degradation of this substance by ascosporogenous yeasts could be stated. Moulds degraded aflatoxin B1 to a high extent. -- With regard to the course of degradation three types can be distinguished. -- In the cultures of moulds two blue fluorescing compounds were found beside aflatoxin B1.

Aflatoxins↗
PubMed1975

Identification of complement-receptor lymphocytes (B cells) in lymph nodes and tumor infiltrates.

To monitor the distribution of lymphocyte sub-populations infiltrating tumors, a simplified modification of standard techniques was developed to identify the complement-receptor B lymphocytes in frozen tissue sections. This technique is based on binding of antibody-coated bovine erythrocytes by B lymphocytes in the presence of sub-hemolytic concentrations of mouse complement. B lymphocytes can be identified in frozen tissue sections by adherent sensitized bovine erythrocytes. The specificity of the technique for B lymphocytes was established by 1) absence of spontaneous rosette formation with bovine erythrocytes by human T lymphocytes, 2) specific binding of bovine erythrocyte-antibody-complement complexes to B cell regions of normal lymph nodes and spleen and 3) binding of erythrocyte-antibody-complement to a high proportion of chronic lymphocytic leukemia (a B cell leukemia) lymphocytes. Five transitional carcinomas studied had regions of mononuclear infiltration that were virtually devoid of complement-receptor lymphocytes. The results suggest that lymphocytes infiltrating bladder carcinomas may be predominantly T lymphocytes.

Animals↗
PubMed1975

Rectus femoris release in selected patients with cerebral palsy: a preliminary report.

Two theories concerning the effects of surgical release of the proximal origins of the rectus femoris in spastic patients are (1) that release reduces hip flexion contracture and lumbar lordosis and diminishes crouch, and (2) that release primarily enhances early swing-phase knee flexion. A series of eight patients with pre-operative electromyography and pre- and post-operative dynamic knee measurements are reviewed. In these patients, back-knee thrust did not improve because it was not caused by rectus contracture. The effect upon hip was also variable: two patients had increased hip flexion and a third had diminished hip flexion after release. In six of the eight patients knee flexion was improved in early swing phase. Improvement from surgery can be expected when rectus spasticity is sufficient (1) to interfere with the initiation of swing phase, and (2) to decrease the amplitude of knee flexion. Little change occurred in the patients who did not have these functional deficits. A review of the cases supports the primary knee effect theory of Silfvenskiöld; however, insufficient information was obtained from this series to rule out hip and pelvic changes.

Adolescent↗
PubMedDate not supplied

Suicide by injection of snake venom.

An unusual suicide is described where the deceased, a schizophrenic young man in perfect physical health, deliberately injected himself subcutaneously with snake venom, by means of a syringe. The circumstances, autopsy findings and laboratory investigations are recorded.

Adult↗
PubMedDate not supplied

Trimethoprim-sulfamethoxazole in the treatment of otitis media caused by ampicillin-resistant strains of Haemophilus influenzae.

Trimethoprim-sulfamethoxazole (TMP-SMZ) was successful treatment for 93% of cases of acute otitis media caused by ampicillin-resistant Haemophilus influenzae studied. All 15 children in this study had symptoms of otitis media that were unrelieved by a course of ampicillin therapy, but 14 of them responded promptly to a 10-day course of TMP-SMZ. Potentially invasive type b strains of H. influenzae were isolated in cultures of the middle ear exudate of three children, all of whom responded well to TMP-SMZ therapy. The middle ear isolates of H. influenzae were sensitive in vitro to TMP-SMZ. It is concluded that TMP-SMZ is effective and convenient for the treatment of otitis media caused by ampicillin-resistant H. influenzae.

Ampicillin↗
PubMedDate not supplied

A new tool to measure pressure under burn garments.

This article introduces a new tool to measure the pressure that is under pressure garments. The Iscan (Tekscan, Inc.) system uses a patented ultra-thin (0.007 inch) sensor with multiple sensing locations that sample continuously at 100 times per second. It is noninvasive, convenient, and quick. The study had two parts. First, we established the validity and reliability of the device. Next, garment/scar interface pressures were measured on new garments with use of the Iscan system. Four garment types were studied, with 10 measurements made in each group: Isotoner gloves (Smith & Nephew Roylan, Inc.); custom-fit pressure gloves; Tubigrip forearm sleeves (Seton Health Care Group); and custom-fit pressure forearm sleeves. Mean garment/scar interface pressures were 18 +/- 2 mm Hg for the Isotoner glove, 34 +/- 5 mm Hg for the custom-fit pressure glove, 20 +/- 7 mm Hg for the Tubigrip sleeve, and 35 +/- 6 mm Hg for the custom-fit sleeve. We concluded that the Iscan system can be used to measure pressure under pressure garments accurately and reliably, and that custom-fit hand and forearm garments provide more pressure than Isotoner gloves or Tubigrip sleeves.

Bandages↗