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Biomedical subjects

J Stoll

Publications and source records attributed to J Stoll.

53 records · Page 3Linked to original sources
PubMed1987

Trypsin-like activity in subgingival plaque. A diagnostic marker for spirochetes and periodontal disease?

Taxonomic screening of subgingival plaque organisms with various enzyme assays have shown that Treponema denticola, Bacteroides gingivalis and an unspeciated Capnocytophaga species possess a trypsin-like enzyme (TLE) that can be detected by the hydrolysis of N-benzoyl-DL-arginine-2-naphthylamide (BANA). As these organisms can be considered to be periodontopathic, it was of interest to determine whether this BANA hydrolyzing enzyme could be detected directly in subgingival plaque samples. Subgingival plaque samples were collected from single sites of known pocket depth, and after dispersal by vortexing, aliquots were incubated overnight with BANA and were counted microscopically. The color reactions were developed with fast garnet, read by the eye and classified as positive (red to red-orange), negative (yellow) and questionable. In the BANA-positive plaques, the spirochetes averaged 43% of the microscopic count, whereas in the BANA negative plaques the spirochetes averaged 8% of the microscopic count. The average pocket depth of BANA-positive plaques was 6.7 mm, whereas the average pocket depth of BANA-negative plaques was 4.5 mm. When both of these parameters were combined, the presence of a positive BANA reaction was usually indicative of subgingival plaques containing greater than 34% spirochetes removed from sites that had probing depths of 7 mm or more. Seventy-one per cent of the plaques removed from untreated periodontal patients were BANA-positive, while only 8% of the plaques removed from successfully treated patients seen at maintenance recall visits were BANA-positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteroides↗
PubMed1985

A single enzyme catalyzes the synthesis of the mannosylphosphoryl derivative of dolichol and retinol in rat liver and Chinese hamster ovary cells.

It is well established that mannosylphosphoryldolichol participates in the synthesis of N-linked glycoproteins by donating mannosyl residues to oligosaccharide-lipid intermediates. It has been suggested that mannosylphosphorylretinol also is involved in glycoprotein biosynthesis. We conclude that one synthase catalyzes the synthesis of both mannosylphosphoryldolichol and mannosylphosphorylretinol in rat liver tissue and Chinese hamster ovary cells, based on the following results. 1) The enzyme in rat liver microsomes that synthesizes mannosylphosphoryldolichol and mannosylphosphorylretinol is inactivated at the same rate at 55 degrees C. 2) In membranes of both rat liver and Chinese hamster ovary cells, exogenous dolichyl phosphate and retinyl phosphate compete with each other for mannosyl-lipid synthesis. However, in both systems adding exogenous retinyl phosphate has no effect on the synthesis of mannosylphosphoryldolichol from endogenous dolichyl phosphate in the membranes. 3) Membranes prepared from a mutant of Chinese hamster ovary cells which is devoid of mannosylphosphoryldolichol synthase lack the ability to synthesize mannosylphosphorylretinol.

Animals↗
PubMed1984

Metronidazole in periodontitis. I. Clinical and bacteriological results after 15 to 30 weeks.

The statistical association of certain anaerobic organisms such as black pigmented bacteroides (BPB) species and spirochetes with clinical signs of active periodontitis, i.e. bleeding upon probing and bone loss, suggests that the lesions may actually reflect a "specific infection" involving these or unidentified species. All the known oral species of BPB and spirochetes are anaerobes which suggests that antimicrobial treatment directed specifically against anaerobes might be effective in periodontal therapy. In this report, the short-term results of metronidazole treatment plus mechanical debridement in patients with extensive periodontal disease and of a double-blind clinical study in which metronidazole plus mechanical debridement is compared to placebo plus mechanical debridement are described. The findings indicate that 1 week of systemic metronidazole can optimize the clinical reduction of pockets and increase the apparent attachment in periodontitis patients who receive concurrent mechanical debridement of their root surfaces. In patients with extensive clinical involvement, metronidazole resulted in a significant reduction in the number of sites exhibiting pocket depths and attachment loss greater than or equal to 7 mm. When metronidazole plus mechanical debridement was compared with placebo plus mechanical debridement in a double-blind study, the metronidazole patients exhibited a significant improvement in those sites initially greater than or equal to 7 mm. The beneficial effect of the metronidazole was associated with a significant and sustained reduction of certain anaerobic organisms such as Bacteroides gingivalis and the large spirochetes. These data indicate that treatment aimed specifically toward the anaerobic component of the plaque flora can be associated with impressive clinical improvements 15 to 30 weeks after the initiation of treatment.

Alveolar Process↗
PubMed1983

Does the female life span exceed that of the male? A study in Drosophila melanogaster.

A survey of all the papers relating to life span in Drosophila melanogaster published in Experimental Gerontology from its origin in 1964 to 1981 shows that, contrary to a common belief, the mean life span of females exceeds that of males in only approximately 50% of the cases. It is shown that mean life span, as it is measured in most experiments, is a poor estimate of the potential life span of a Drosophila strain. However, the analysis of four extensive studies of Drosophila melanogaster life span strongly suggests that the potential (or maximal) life span is consistently higher for females than it is for males. That analysis also shows that, vis-à-vis the controlled or uncontrolled variations of the environment, the males have a broader norm of reaction or, in other words, a smaller homeostasis than the females. A model, mainly based on these two results, allows us to explain how the mean life span of males is so often higher than that of females.

Aging↗
PubMed1982

Mutant of Chinese hamster ovary cells with altered mannose 6-phosphate receptor activity is unable to synthesize mannosylphosphoryldolichol.

B4-2-1 is a Chinese hamster ovary cell mutant previously isolated and characterized as deficient in mannose 6-phosphate receptor activity. We show here that B4-2-1 is a pleiotropic mutant, defective in biosynthesis of asparagine-linked oligosaccharides, B4-2-1 is unable to synthesize mannosylphosphoryldolichol; the consequences of this defect on glycosylation are (i) biosynthesis of one major lipid-linked oligosaccharide, characterized by its resistance to endoglycosidase H and decreased size; this oligosaccharide is similar to a minor species of lipid-liked oligosaccharide found in parental cells; (ii) transfer of this oligosaccharide to newly synthesized proteins; and (iii) absence of normal "high-mannose" oligosaccharides on mature glycoproteins isolated from B4-2-1; glycoproteins from the mutant contain complex oligosaccharides as well as endoglycosidase H-resistant, alpha-mannosidase-sensitive species. While the glycosylation defect may alter adversely the function of several glycoproteins in the mutant, including that of the mannose 6-phosphate receptor, it appears to have no effect on the formation or function of the mannose 6-phosphate recognition marker on acid hydrolases of B4-2-1.

Animals↗
PubMed1982

The bacteriology of acute necrotizing ulcerative gingivitis.

Plaque samples from 22 ulcerated sites in eight patients with ANUG were cultured using quantitative anaerobic procedures and were examined microscopically. The partial characterization of the predominant cultivable flora revealed a constant flora comprised of a limited number of bacterial types and a variable flora composed of a heterogeneous array of bacterial types. This constant flora would appear to be pathognomonic of acute necrotizing ulcerative gingivitis (ANUG) and included the various Treponema and Selenomonas sp., which comprised about 32 and 6%, respectively, of the microscopic count; B. melaninogenicus ssp. intermedius and Fusobacterium sp., which averaged 24 and 3%, respectively, of the viable count. One week of metronidazole treatment caused a prompt resolution of clinical symptoms, which coincided with a significant reduction in the plaque proportions of the Treponema sp., B. melaninogenicus ssp., intermedius and Fusobacterium sp. for at least 2 to 3 months following treatment. Thus, the same anaerobic species which were numerically associated with the ANUG lesion were also selectively reduced in the plaque flora following resolution of the infection. This supports a role for the above species in the ulcerative stage of the lesion but does not demonstrate that these specific anaerobes initiated the infection. although not confirmed by the data, it was proposed that these particular anaerobic species gained ascendency in the plaque as a result of being selected through the availability of host-derived nutrients in individuals who had undergone certain physiological and psychological stresses.

Bacteria↗
PubMed1981

Comparison of Marion's anaerobic culture/set-A and the Baltimore Biological Laboratory Gaspak anaerobic system in the cultivation and recovery of bacteria from human dental plaque.

Marion's anerobic culture/set-A (Bio-Bag A) and the Baltimore Biological Laboratory (BBL) Gaspak anaerobic system were evaluated for their efficiency in the cultivation and recovery of anaerobes and capnophilic organisms from human dental plaque samples. Both culture systems were relatively efficient in supporting the growth of pure culture of various bacterial species recently isolated from the human dental plaques. When the dental plaque samples were cultured the organisms commonly found were cultivatable in both culture systems. However, the counts and proportions of Fusobacterium nucleatum from the samples were significantly higher in Marion's culture system, whereas the proportions of black-pigmented Bacteroides sp. were significantly higher in the BBL anaerobic system.

Actinomyces↗
PubMed1979

An attempt to select for increased longevity in Drosophila melanogaster.

Eight generations of selection towards a higher longevity were made in a wild strain of Drosophila melanogaster. Two control lines were also observed. Absolutely no response to selection was obtained whilst a major increase in longevity occurred between F2 and F4 in the three lines under observation. It is shown that the major increase in longevity is due neither to genetic drift, nor to changes in classical environmental conditions. The absence of response to selection is demonstrated to be due neither to a too low selection differential, nor to the absence of genetic variability in the strain, nor to inaccuracy in the measurements, nor to recurrent reproduction at an old age. The impossibility to select towards a higher longevity and the total absence of relation between parental and offspring longevities demonstrate that the very large phenotypic variability displayed by longevity in wild strains of D. melanogaster does not depend on a precise set of specific genes or polygenes with additive action. The results are briefly discussed in relation with inbreeding depression and heterosis for longevity and with similar results obtained in experiments of selection for duration of development.

Animals↗
PubMedDate not supplied

Altered long-term potentiation in the young and old Ts65Dn mouse, a model for Down Syndrome.

We investigated the phenomenon of long-term potentiation (LTP) in a genetic model of Down Syndrome, the segmental trisomy mouse (Ts65Dn). Ts65Dn mice survive to adulthood and have an extra chromosome that contains a segment of chromosome 16 homologous to human chromosome 21. In this study, field excitatory postsynaptic potentials (fEPSP) were recorded from the CA1 area of in vitro hippocampal slices from diploid and Ts65Dn mice, and LTP was induced by a single tetanizing pulse train (1 sec in duration) at 100 Hz. The hippocampus from both young (2 months) and older (9 months) Ts65Dn mice had a reduced LTP over a period of 60 min compared with LTP in age-matched controls. This finding may explain the reported behavioral and learning impairments in Ts65Dn mice; it suggests that this mouse model can be used to study the role of altered synaptic plasticity in mental retardation of Down Syndrome.

Aging↗
PubMedDate not supplied

Segmental spinal instrumentation for congenital scoliosis. A report of two cases.

Two patients with congenital scoliosis underwent surgical correction with segmental spinal instrumentation and fusion. This technique, coupled with spinal monitoring, provides greater correction of a curve than does cast treatment and eliminates the risk of neurologic injury associated with distraction.

Adolescent↗