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Biomedical subjects

S Garrett

Publications and source records attributed to S Garrett.

At least 73 records · Page 4Linked to original sources
PubMed1991

A DNA primer/probe system for the rapid and sensitive detection of Mycobacterium tuberculosis-complex pathogens.

A 1.5 kb EcoRI-BamHI restriction fragment from Mycobacterium tuberculosis was found to hybridize specifically with genomic DNA from M. tuberculosis-complex organisms. Primers were designed from the terminal sequences of this fragment and used to amplify uniquely M. tuberculosis-group DNA in a polymerase chain reaction. It is suggested that a combination of these primers and probe will prove a useful tool for the early diagnosis of tuberculous infections.

Base Sequence↗
PubMed1991

The Saccharomyces cerevisiae YAK1 gene encodes a protein kinase that is induced by arrest early in the cell cycle.

Null mutations in the gene YAK1, which encodes a protein with sequence homology to known protein kinases, suppress the cell cycle arrest phenotype of mutants lacking the cyclic AMP-dependent protein kinase (A kinase). That is, loss of the YAK1 protein specifically compensates for loss of the A kinase. Here, we show that the protein encoded by YAK1 has protein kinase activity. Yak1 kinase activity is low during exponential growth but is induced at least 50-fold by arrest of cells prior to the completion of S phase. Induction is not observed by arrest at stages later in the cell cycle. Depending on the arrest regimen, induction can occur either by an increase in Yak1 protein levels or by an increase in Yak1 specific activity. Finally, an increase in Yak1 protein levels causes growth arrest of cells with attenuated A kinase activity. These results suggest that Yak1 acts in a pathway parallel to that of the A kinase to negatively regulate cell proliferation.

Base Sequence↗
PubMed1991

Treatment of periodontal furcation defects. Mandibular class III defects.

Twenty-seven mandibular class III furcation defects were treated in 27 subjects using a regenerative therapy that included citric acid root conditioning and coronally positioned flaps secured by crown-attached sutures. In addition to this therapy, 13 of the 27 defects received freeze-dried, decalcified allogenic bone grafts. The effect of these therapies was evaluated from soft tissue probing measurements, including furcation probings to determine soft tissue closure of the defects. At 6 months postsurgery, the mean vertical probing depth reduction and the mean probing attachment level gain in the furcation area were 2.6 mm and 2.2 mm for the non-grafted defects and 1.9 mm and 1.5 mm for the grafted defects. One of the 14 non-grafted defects and 3 of 13 grafted defects were judged to show soft tissue clinical closure by a panel of 3 independent examiners. No statistically significant differences were observed between defects treated with or without bone grafts.

Bone Transplantation↗
PubMed1991

Coronally displaced flaps in reconstructive periodontal therapy.

This article reviews the approach taken by the Loma Linda University Group in treating molars with Class II and Class III furcation lesions. The surgical technique used is detailed for Class II furcations. The modification of the technique for lingual furcation of lower molars and the postsurgical behavior of a crown-attached flap are also discussed.

Animals↗
PubMed1990

Diagnostic predictability of scores of plaque, bleeding, suppuration and probing depth for probing attachment loss. 3 1/2 years of observation following initial periodontal therapy.

Recordings of supragingival plaque, bleeding, suppuration and probing depth were obtained for 42 months following initial periodontal therapy. Scores accumulated after various time intervals during monitoring were studied for their predictive value in revealing probing attachment loss as determined by regression analysis during the 0-42 month period. Accumulated plaque scores demonstrated low predictability. Accumulated bleeding scores showed modest predictive values. Suppuration on probing was not a frequent finding during the observation interval and also had modest predictive power. Increase in probing depth compared to baseline and deep residual probing depth had modest predictability after 3 and 12 months, but showed increasing accuracy in revealing probing attachment loss over later time intervals. After a few years of maintenance, increase in probing depth, particularly if combined with high frequency of bleeding on probing, showed the highest predictive value for probing attachment loss of the scores examined.

Adult↗
PubMed1990

Treatment of periodontal furcation defects. Coronally positioned flaps versus dura mater membranes in class II defects.

Mandibular class II furcation defects in 19 subjects were treated using 2 different methods of wound closure. In 16 of the defects, the wound was closed with a coronally positioned surgical flap secured by crown-attached sutures. In 15 of the defects, a collagenous membrane (freeze-dried dura mater) was placed to cover the exposed defect, followed by suturing of the surgical flap at the level of the alveolar crest. After use of a coronally positioned flap, an average of 70% of the defect volume became filled with bone, with complete closure by bone fill for 9 of the 16 treated defects. After use of dura mater membrane, 38% of the defect volume was filled with bone, with complete bony closure for 3 of the 15 treated defects. The results following use of coronally positioned flaps support our previous findings and the potentials of this technique. The results following use of dura mater membranes, together with recently reported risk for spread of virus with dura implants, do not justify the use of dura mater for these regenerative purposes.

Adult↗
PubMed1989

Loss of Ras activity in Saccharomyces cerevisiae is suppressed by disruptions of a new kinase gene, YAKI, whose product may act downstream of the cAMP-dependent protein kinase.

The yeast Saccharomyces cerevisiae contains two functionally redundant genes RAS1 and RAS2, which are homologous to the mammalian ras gene family and are required for vegetative growth. We isolated and characterized five temperature-sensitive alleles of RAS2. In a ras1 strain, these alleles cause growth arrest at the G1 stage of the cell cycle. Revertants capable of growth at the nonpermissive temperature define four recessive, extragenic complementation groups. Suppressors in one complementation group (designated yak1) are particularly intriguing because they appear to alleviate only the growth defect of the temperature-sensitive ras mutants and do not show any of the phenotypes, such as heat shock sensitivity or starvation sensitivity, associated with increased production of cAMP. The YAK1 gene has been cloned, and disruptions generated in vitro reveal that it is not essential for growth and that its loss confers growth to a strain deleted for tpk1, tpk2, and tpk3, the structural genes for the catalytic subunit of the cAMP-dependent protein kinase. These results place Yak1 downstream from, or on a parallel pathway to, the kinase step in the Ras/cAMP pathway. Finally, the coding region predicts a protein with significant homology to the family of protein kinases, suggesting that loss of cAMP-dependent protein kinase function can be suppressed by the loss of a second protein kinase.

Amino Acid Sequence↗
PubMed1988

Treatment of intraosseous periodontal defects with a combined adjunctive therapy of citric acid conditioning, bone grafting, and placement of collagenous membranes.

A total of 25 proximal, intraosseous periodontal defects were treated in 21 adult patients. A 3-prong adjunctive, regenerative treatment approach was used. The treatment included (1) citric acid conditioning of the root surfaces, (2) grafting of particles of decalcified, freeze-dried homologous bone, and (3) placement of freeze-dried, homologous dura mater sheets between the replaced surgical flaps and the tooth surfaces. The results, as evaluated by probing attachment and probing bone level measurements, during 1 year of observation, demonstrated limited improvements of the treated defects. The limited results were similar to previous observations in our clinics following treatment of intraosseous defects using different treatment modalities. It appears that new treatment approaches need to be sought to accomplish clinically significant and predictable regeneration in proximal, intraosseous periodontal defects.

Adult↗
PubMed1988

Treatment of periodontal furcation defects. (I). Review of the literature and description of a regenerative surgical technique.

This report provides an abbreviated review of the literature on treatment and prognosis of periodontal furcation lesions. In addition, it describes a surgical technique designed to accomplish bone regeneration in class II furcation defects, together with the rationale for the development of this procedure. Results of treatment of 30 defects with this technique are presented in a subsequent report.

Bone Regeneration↗
PubMed1988

Treatment of periodontal furcation defects. (II). Bone regeneration in mandibular class II defects.

A total of 30 mandibular, buccal class II furcation defects were treated in 22 subjects using a regenerative surgical therapy that included citric acid root conditioning and coronally positioned flaps secured by crown-attached sutures. In addition, grafts of freeze-dried, decalcified allogenic bone were placed in 16 of the 30 defects. The effect of the therapies was evaluated from a series of soft and hard tissue measurements. These measurements demonstrated notable improvement 12 months following therapy. On the average, 67% of the defect volume became filled with bone. 43% of treated defects were completely closed by bone fill. No difference was observed between defects treated with and without bone grafts.

Adult↗
PubMed1988

EnvZ functions through OmpR to control porin gene expression in Escherichia coli K-12.

The regulatory proteins OmpR and EnvZ are both required to activate expression of the genes for the major outer membrane porin proteins, OmpF and OmpC, of Escherichia coli K-12. Here we show that OmpR, under certain conditions, could activate porin expression in the complete absence of EnvZ. In addition, the pleiotropic phenotypes conferred by a particular envZ mutation (envZ473) required the presence of functional OmpR protein. These results lead us to conclude that EnvZ and OmpR act in sequential fashion to activate porin gene expression; i.e., EnvZ modifies or in some way directs OmpR, which in turn acts at the appropriate porin gene promoter.

Bacterial Outer Membrane Proteins↗
PubMed1987

Prevention of Haemophilus influenzae type b infections in high-risk infants treated with bacterial polysaccharide immune globulin.

Apache Indian infants have a high frequency of Haemophilus influenzae type b (Hib) and pneumococcal infections. Forty percent of Hib infections in these infants occur before the age of six months, when active immunization may not be protective. To evaluate the efficacy of passive immunization with a human hyperimmune globulin (bacterial polysaccharide immune globulin [BPIG]) prepared from the plasma of immunized adult donors, we randomly assigned 703 infants in a double-blind fashion to receive 0.5 ml of BPIG per kilogram of body weight (n = 353) or 0.5 ml of saline (n = 350) intramuscularly at 2, 6, and 10 months of age. Hib-antibody levels were significantly higher in BPIG recipients than in placebo recipients at 4, 6, and 10 months of age (P less than 0.001). During the first 90 days after BPIG or placebo injection, no Hib or pneumococcal infections were detected in the BPIG group, whereas seven Hib infections (six cases of bacteremia and one of meningitis) and four pneumococcal infections (bacteremia) were detected in the placebo group (P = 0.007 and 0.06, respectively). During the fourth month, one case of Hib meningitis and two cases of pneumococcal bacteremia developed in the BPIG group, whereas there were no Hib or pneumococcal infections in the placebo group. We conclude that BPIG given at four-month intervals provided significant protection against serious Hib disease for three months, and that in high-risk infants it might be used alone, perhaps at three-month intervals, or together with active immunization.

Antibodies, Bacterial↗
PubMed1987

Bleeding on probing and probing depth as indicators of the response to plaque control and root debridement.

19 adult periodontitis patients were treated with plaque control and a single episode of root debridement. Results of this treatment were monitored in non-molar sites, molar flat surface sites, and molar furcation sites by probing attachment level measurements every 3rd month for 24 months. After 24 months, sites with probing attachment loss were identified using linear regression analysis. Clinical scores for supragingival plaque, bleeding on probing, suppuration on probing, and probing depth, obtained from these sites during the 24-month study, were analyzed to determine if they could be used diagnostically as indicators of probing attachment loss. The results demonstrated that the diagnostic accuracy for these clinical indicators was generally low at all 3 anatomical site locations. A possible explanation for this limited diagnostic accuracy may be that some areas of probing attachment loss following basic periodontal therapy are caused by factors other than the progression of an inflammatory periodontal disease of microbial etiology.

Adult↗
PubMed1987

The effect of plaque control and root debridement in molar teeth.

The healing response of non-molar sites, molar flat surface sites, and molar furcation sites was investigated in 19 adult periodontitis patients following a periodontal therapy of plaque control and root debridement. A total of 2472 sites were monitored by recordings of dental plaque, bleeding on probing, probing depth, and probing attachment levels every 3rd month for 24 months. The results demonstrated that in sites with initial probing depth of 4.0 mm or greater, molar furcation sites responded less favorably to the therapy as compared to molar flat surface sites or non-molar sites. This was demonstrated by higher mean scores for bleeding on probing, less reduction in probing depth, and a mean loss of probing attachment of 0.5 mm over 24 months. Site analyses using linear regression showed a higher % of deeper sites with probing attachment loss for the molar furcations than either molar flat surface or non-molar sites. Among sites initially 7.0 mm or deeper, 21% of molar furcations were identified as showing probing attachment loss as compared to 7% of the molar flat surface sites and 11% of the non-molar sites.

Adult↗
PubMed1987

Isolation of mutations in the alpha operon of Escherichia coli that suppress the transcriptional defect conferred by a mutation in the porin regulatory gene envZ.

One class of mutations in the envZ gene of Escherichia coli K-12 confers a pleiotropic defect on the expression of several genes, including ompF, lamB, and phoA, that are otherwise not commonly regulated. Four second-site mutations that suppress this transcriptional defect have been isolated by using a procedure that circumvented the problem of intragenic suppressors, including true revertants. All four mutations have been mapped to the genes of the alpha operon and have been assigned tentatively to the gene rpoA, which specifies the alpha subunit of RNA polymerase. The mutations, referred to as sez (for suppressor of envZ), did not appear to confer a phenotype on an otherwise wild-type strain and did not suppress the transcriptional defects conferred by several other phenotypic classes of envZ mutations, including amber mutations. Our results led us to postulate that the alpha subunit or some other component of the alpha operon plays a role in determining the specificity of gene expression.

Bacterial Outer Membrane Proteins↗
PubMed1986

Glycine-based oral rehydration solution: reassessment of safety and efficacy.

We evaluated the safety and efficacy of a glycine-based orally administered rehydration solution by comparing it with a standard oral rehydration solution (ORS) without glycine in a randomized double-blind trial in United States infants (age less than 15 months) given treatment for acute gastroenteritis as inpatients or outpatients. The response to therapy (stool volume and duration of illness) was similar in the two groups, except that in four (13%) of 31 hospitalized infants receiving glycine-ORS hypernatremia developed, (one had symptoms) compared with none of 35 receiving ORS (P less than 0.04). Among the 77 outpatients there were no differences between the groups. This study demonstrates that glycine-ORS did not provide any therapeutic advantage over standard ORS, and hypernatremia developed in some patients receiving glycine-ORS. We suggest that caution be used with this type of solution until further safety studies have been done.

Anti-Bacterial Agents↗