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S Stuart

Publications and source records attributed to S Stuart.

49 records · Page 3Linked to original sources
PubMed1987

Rate of replication of the murine immunoglobulin heavy-chain locus: evidence that the region is part of a single replicon.

We measured the temporal order of replication of EcoRI segments from the murine immunoglobulin heavy-chain constant region (IgCH) gene cluster, including the joining (J) and diversity (D) loci and encompassing approximately 300 kilobases. The relative concentrations of EcoRI segments in bromouracil-labeled DNA that replicated during selected intervals of the S phase in Friend virus-transformed murine erythroleukemia (MEL) cells were measured. From these results, we calculated the nuclear DNA content (C value; the haploid DNA content of a cell in the G1 phase of the cell cycle) at the time each segment replicated during the S phase. We observed that IgCH genes replicate in the following order: alpha, epsilon, gamma 2a, gamma 2b, gamma 1, gamma 3, delta, and mu, followed by the J and D segments. The C value at which each segment replicates increased as a linear function of its distance from C alpha. The average rate of DNA replication in the IgCH gene cluster was determined from these data to be 1.7 to 1.9 kilobases/min, similar to the rate measured for mammalian replicons by autoradiography and electron microscopy (for a review, see H. J. Edenberg and J. A. Huberman, Annu. Rev. Genet. 9:245-284, 1975, and R. G. Martin, Adv. Cancer Res. 34:1-55, 1981). Similar results were obtained with other murine non-B cell lines, including a fibroblast cell line (L60T) and a hepatoma cell line (Hepa 1.6). In contrast, we observed that IgCh segments in a B-cell plasmacytoma (MPC11) and two Abelson murine leukemia virus-transformed pre-B cell lines (22D6 and 300-19O) replicated as early as (300-19P) or earlier than (MPC11 and 22D6) C alpha in MEL cells. Unlike MEL cells, however, all of the IgCH segments in a given B cell line replicated at very similar times during the S phase, so that a temporal directionality in the replication of the IgCH gene cluster was not apparent from these data. These results provide evidence that in murine non-B cells the IgCH, J, and D loci are part of a single replicon.

Abelson murine leukemia virus↗
PubMed1986

Clonal analysis of Escherichia coli O2:K1 isolated from diseased humans and animals.

Forty-six Escherichia coli isolates of serotype O2:K1 from human urinary tract infections, chicken sepsis, and bovine mastitis were obtained from laboratories in England, Denmark, Sweden, and Finland. The bacteria were compared for outer membrane protein (OMP) pattern, lipopolysaccharide pattern, electrophoretic mobilities of enzymes, and flagellar serotype and were tested for fimbriation, biotype, hydroxamate production, hemolysin production, antibiotic resistance, plasmid content, colicin production, and virulence in neonatal rats. Isolates from humans were assigned to two clonal groups; poultry isolates belonged to one of these clonal groups, whereas bovine isolates belonged to the other. Poultry and human isolates of the same clonal group could be distinguished only by their plasmid content. Strains within this group were heterogeneous with respect to biotype, fimbriation, virulence, and flagellar serotype. Human and bovine isolates of the second clonal group were distinguished by a minor change in OMP pattern and by their plasmid content. It is concluded that meaningful clonal groupings are best recognized by the combination of OMP and electrophoretic enzyme patterns. The O:K serotype can aid in the recognition of important subclones, whereas the other microbiological properties tested can vary widely within clonal groupings. Furthermore, we conclude that certain O:K serotypes can contain very different clonal groupings having little genetic relatedness.

Animals↗
PubMed1985

Use of histidine dipeptides and myoglobin to monitor adulteration of cooked beef with meat from other species.

A new high performance liquid chromatography (HPLC) method was used to monitor the adulteration of cooked beef products with meat from other species. The ratio of the histidine dipeptides anserine and carnosine which are present in skeletal muscle, are so different between sheep, cattle, horse and kangaroo that detection of adulteration can be rapidly achieved by chromatography on a Partisil-10 SCX column with 0.2 M lithium formate, pH 2.9. To obtain a definitive identification of the adulterant it was necessary to also examine the electrophoretic mobility of myoglobin in sodium dodecylsulphate gels. One brand of "beefsteak" pie was found to actually be a mixture of mutton and beef.

Animals↗
PubMed1982

Acute lethal graft-versus-host disease stimulates cellular proliferation in the adult rat liver.

The present investigation was designed to analyse the effects of acute lethal graft-versus-host disease (GVHD) in adult (DA x LEW)F1 rats on cellular proliferation within the liver. The influence of the host thymus on GVHD-induced proliferation was also assessed. From 1-28 days after initiation of GVHD [3H]thymidine ([3H]-TdR) was injected i.v. and rats were killed one hour later. Percentage labelled cells (LI) of periportal infiltrating cells (PIC), hepatocytes (H), and sinusoidal lining cells (SC) were counted. Mean values for control rats were 0.3 +/- 0.1% (H), 0.4 +/- 0.1% (SC) and 0.2 +/- 0.1% (PIC). GVHD rats demonstrated a significant increase in LI of PIC (days 1-21), SC (days 2-17) and H (days 2-17). Most labelled cells in PIC were large lymphocytes. Peak LI values were 7.0 +/- 1.0% PIC (day 17), 6.8 +/- 0.9% SC (day 17), and 5.2 +/- 0.9% H (day 7), with all cellular compartments returning to near normal LI values by day 28. Stimulation of cellular proliferation occurred in all three liver cell compartments in neonatally thymectomized (TXM) rats. The intensity of GVHD-induced cell proliferation was significantly decreased at day 7 in all compartments and PIC was dramatically decreased at day 21 in TXM-GVHD rats as compared to non-TXM-GVHD rats. It is hypothesized that the general stimulation of hepatocyte cell proliferation in GVHD is related to the secretion of lymphokines by primarily donor and secondarily host T cells in the periportal infiltrate.

Animals↗
PubMed1980

The effects of iopodate on the serum iodothyronine pattern in normal subjects.

The ingestion by normal subjects of 3 g of sodium iopodate, which is widely used in routine oral cholecystography, resulted in significant decreases of serum total and free T3 to a nadir on day 4 which averaged 43% and 40%, respectively, below initial mean values. Total and free rT3 increased markedly to a peak on day 3, 244% and 189%, respectively, above initial mean values. Total and free T4 and free T4 index rose to a maximum on day 4, but these changes were not statistically significant. A marked TSH increase was also seen, most evident on day 3. All these changes reverted to baseline values by day 14 at a time when serum total iodide was still markedly elevated. It is concluded that the changes observed after iopodate were not due to alterations in serum binding proteins nor to an effect on thyroid gland by the large iodine component of iopodate, but were consistent with an effect on the peripheral metabolism of T4. Difficulty in interpreting routine thyroid function tests may occur for up to 14 days after oral cholecystography with iopodate.

Adult↗
PubMedDate not supplied

Attachment and interpersonal communication in somatization.

The authors review the research on childhood antecedents and personality contributions to the somatoform disorders, as well as research on social influences during adulthood. Based on these data, the authors hypothesize that somatizing patients display anxious attachment behavior that derives from childhood experiences with caregivers. Early exposure to illness increases the likelihood that distress will be manifested somatically. When under stress as adults, somatizers use physical complaints to elicit care. Somatizers' interpersonal interactions with others, including physicians, ultimately lead to rejection that reinforces the somatizer's belief that he or she will be abandoned. Modification of physicians' responses to these patients may improve treatment outcomes.

Adolescent↗
PubMedDate not supplied

Breaststroker's knee: pathology, etiology, and treatment.

Twenty-three breaststroke swimmers (ranging in age from 6 to 30 years old) with painful knees were examined. Underwater movies of these swimmers were taken. Eighteen swimmers had tenderness under the medial facet of the patella and over the medial femoral intercondylar ridge. Five of these 18 swimmers also had tenderness along the tibial collateral ligament. Five swimmers had tenderness just along the tibial collateral ligament. The onset of knee pain usually occurred within 3 years of the swimmers' beginning the breaststroke. Initially, the knees were only symptomatic when the swimmers performed the whipkick. As the swimmer continued the breaststroke, in spite of discomfort, the knees became symptomatic during other athletic and nonathletic activity. Breaststroke who had been using the whipkick for more than 8 years had clinical evidence of patellofemoral osteoarthritis. The site of pain in the knee was related to the way in which the whipkick was performed. Breaststroke without knee pain used a whipkick with characteristics that were consistently different than those of the symptomatic swimmers. Treatment of breaststroke's knee should be directed toward correcting the swimmer's whipkick. This approach is most likely to be successful if applied as soon as the swimmer becomes symptomatic.

Adolescent↗