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Biomedical subjects

S Olson

Publications and source records attributed to S Olson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Specific cementum attachment protein enhances selectively the attachment and migration of periodontal cells to root surfaces.

A specific cementum attachment protein (CAP) was identified in human cementum and found to bind with high affinity to non-demineralized root surfaces, hydroxyapatite and fibronectin. Attempting to elucidate the biological function of this protein and its possible role in cementogenesis the capacity of CAP to promote selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro was assessed. Human gingival fibroblasts (HGF), periodontal ligament cells (HPC), and alveolar bone cells (HABC) were labeled with [3H]Thymidine during their exponential growth phase. Root slices, 300 microns thick, were incubated with increasing concentrations of CAP. Untreated and fibronectin (FN) treated root slices served as negative and positive controls, respectively. Migration was assessed by placing root slices on confluent layers of labeled cells maintained in serum free medium and determining the number of cells migrated onto the root surface 3 days thereafter. Attachment was assessed by incubating root slices with labeled cell suspensions for 2 h and determining the number of attached cells. CAP promoted both cell migration and attachment dose dependently. HABC responded better than HPC and HGF to CAP treated root slices, and HPC response was higher than that of HGF. Cell attachment was dose dependently inhibited by synthetic RGD peptides. FN did not affect the migration of HGF, barely enhanced that of HABC, and was less potent than CAP at enhancing the migration of HPC. FN was more effective than CAP in promoting the attachment of HGF to root slices, but it was as potent as CAP in supporting the attachment of HPC and HABC.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗
PubMed1994

A novel pathway of thymus-directed T lymphocyte maturation.

Recent evidence has indicated that the intestinal epithelium may be a major extrathymic site of T cell production. However, which of the multiple intestinal intraepithelial lymphocyte (IEL) subsets are extrathymic in origin has been controversial. We now report that the thymus is an integral component of IEL maturation and is required for a novel two-stage process of T cell production. Thus, in neonatally thymectomized mice TCR-gamma delta IELs were depleted and some TCR-alpha beta IELs were of an immature phenotype. Thymus grafting experiments revealed that all TCR-gamma delta and TCR-alpha beta IEL subsets could be thymus-derived, including TCR-alpha beta cells lacking Thy1 and CD8 beta. In utero anti-TCR-gamma delta mAb treatments resulted in depletion of gamma delta IEL without subsequent re-emergence of this subset in adulthood, whereas anti-TCR-alpha beta mAb treatment only marginally reduced the alpha beta IEL subset. These findings suggest that TCR-alpha beta and TCR-gamma delta IELs arose at distinct developmental stages. Overall, the results indicate that some IEL precursors are thymus-derived but require further thymic influence to mature in the periphery.

Age Factors↗
PubMed1994

Clinical, histologic, and ultrastructural evaluation of tattoos treated with three laser systems.

We examined the response of tattoo pigments treated with three commercially available lasers: Q-switched ruby, Q-Switched neodynium:yttrium,aluminum,garnet (Nd:YAG), and the alexandrite. Tattoos applied to hairless guinea pigs and treated with the aforementioned lasers were evaluated clinically, histologically, and ultrastructurally. Clinical evaluation showed red brown, dark brown, and orange pigment responded best to the Nd:YAG laser (1064 nm). The alexandrite laser was most effective for removing blue and green pigment, the Q-switched ruby laser was most effective for removing purple and violet pigment, and the Nd:YAG laser (532 nm) removed red pigment the best. Black pigment was lightened equally with the Nd:YAG laser (1064 nm) and (532 nm) and the alexandrite laser (755 nm). No clinical scarring was observed; however, some colors turned black after treatment. Histologic and ultrastructural examination showed epidermal and dermal damage to be most evident after treatment with the Nd:YAG laser. Our study shows that certain tattoo pigments respond better to different laser systems.

Aluminum Oxide↗
PubMed1994

Interactions between stem cell factor and c-Kit are required for intestinal immune system homeostasis.

Interactions between stem cell factor (SCF) and its receptor, c-Kit, are important for development of hematopoietic, melanocytes, and germ cells. T lymphocytes appeared normal in c-Kit (W/Wv) or SCF (SI/SId) mutant mice, except for those residing within the intestinal epithelium, the intraepithelial lymphocytes (IEL). Normally, IEL are composed of equal numbers of cells with alpha beta or gamma delta T cell receptors. In mutant mice, beginning at 6-8 weeks of age, the number of gamma delta IEL decreased, whereas alpha beta IEL increased. The latter was due largely to an increased CD4+ CD8+ TCR alpha beta subset, suggesting that these cells may be intermediates in the alpha beta IEL lineage. c-Kit or SCF was expressed by IEL or intestinal epithelial cells, respectively, indicating a potential for direct intercellular interaction. This possibility was supported by reconstitution studies that demonstrated that c-Kit mutations directly affected IEL. Thus, SCF-c-Kit interactions are important for homeostasis of the intestinal immune compartment.

Animals↗
PubMed1993

The need to reevaluate trisomy screening for advanced maternal age in prenatal diagnosis.

OBJECTIVES: Fluorescence in situ hybridization aneuploidy screening promises immediate results. To evaluate aneuploidy screening in prenatal diagnosis, the prenatal records at Oregon were reviewed. STUDY DESIGN: Karyotype reports of 7240 amniocentesis samples referred for advanced maternal age were retrospectively reviewed for numeric and structural chromosome abnormalities. RESULTS: The frequency of abnormal karyotypes was 2.5%; 1.4% were age-related trisomies and sex-chromosome aneuploids, and 1.1% were non-age-related abnormalities. The incidence of structural rearrangements was 0.9%, of which 70% were familial but not suspected on the basis of family history. CONCLUSIONS: Structural chromosome abnormalities were twice as common as previously reported, representing a significant unrecognized risk for subsequent pregnancies and other family members. Fluorescence in situ hybridization aneuploidy screening would not routinely detect structural chromosome abnormalities, which were twice as frequent as numeric aneuploidy at age 35 years. Routine use of fluorescence in situ hybridization for prenatal diagnosis should not be adopted without a prospective study of its accuracy, reliability, and impact on prenatal diagnosis.

Amniocentesis↗
PubMed1993

Preliminary evaluation of high-frequency chest compression for secretion clearance in mechanically ventilated patients.

BACKGROUND: A high-frequency chest compression (HFCC) device called the ThAIRapy System has been developed to provide secretion clearance therapy. We evaluated the safety, efficacy, and utility of the device in long-term mechanically ventilated patients. DESCRIPTION OF DEVICE: The primary components of the device are an air-pulse generator and an inflatable vest. Small gas volumes are alternately injected into and withdrawn from the vest by the air-pulse generator at a fast rate, creating an oscillatory or vibratory motion. The pulses cause the vest to inflate and deflate against the thorax of the patient. EVALUATION METHODS: We evaluated HFCC by comparing it to percussion and postural drainage therapy (P&PD); sputum production, patient comfort (PC), pulse-oximetry saturation (SpO2), heart rate (HR), and blood pressure (BP) data were collected and compared between the 2 methods. We monitored the reliability of the device and distributed a survey questionnaire to the entire respiratory therapy staff to assess utility. EVALUATION RESULTS: Nine patients completed the safety and efficacy portion of our evaluation. No significant difference was found between P&PD and HFCC in the wet weight of collected sputum, the mean change-in-percent of SpO2 or the mean percent change from baseline in HR, BP, or PC. All therapists believed that the ThAIRapy System was easy to learn, and 70% considered it an acceptable alternative to P&PD. Of the staff members surveyed, 80% believed that use of the HFCC device resulted in time savings in all or most cases. There were no equipment malfunctions in 225 hours of use. CONCLUSIONS: Compared to P&PD, HFCC via the ThAIRapy System may be equally efficacious in promoting secretion clearance in long-term mechanically ventilated patients. HFCC is neither more nor less safe for patients than is P&PD using SpO2, HR, BP, and PC as outcome variables. Most of our respiratory therapists perceived HFCC as an acceptable alternative to P&PD.

Data Collection↗
PubMed1992

[Montreal families in the nineteenth century: three cultures, three trajectories].

"To trace the evolution of the population of Montreal from the 1840s to the end of the century, we collected all baptisms, marriages, deaths and nominal census entries for 12 sample surnames. The sample is intended to permit matching, chaining, and a full reconstitution of several hundred families representative of each of the city's three principal cultural communities--French Canadian, protestant, and Irish catholic. The three communities functioned as distinctive subsystems, each with its own age-structure, vital rates, and behavioral patterns." (SUMMARY IN ENG AND SPA)

Age Distribution↗
PubMed1992

Renal transplants. Kidney and pancreatic transplantation.

1. Specific criteria for pancreas donation are few. A donor history of diabetes mellitus is an absolute contraindication, as well as any direct trauma to the pancreas with severe pancreatitis. Extracranial malignancy and active infection rule out retrieval of both pancreas and kidneys. 2. A combined pancreas/kidney transplant requires two completely separate instrument setups. The instruments used to implant the pancreas are considered contaminated by the segment of duodenum containing the pancreatic duct. 3. In addition to those questions routinely asked of a patient on admission to the operating room, the perioperative nurse needs to know when the patient last underwent dialysis and when the last dose of insulin was given. Lab work should be quickly reviewed with special notice given to the hematocrit, hemoglobulin, and glucose levels.

Graft Rejection↗
PubMed1991

Localization of two genes encoding plasma membrane Ca2(+)-transporting ATPases to human chromosomes 1q25-32 and 12q21-23.

Human plasma membrane Ca2(+)-ATPase (PMCA) isoforms are encoded by at least four separate genes and the diversity of these enzymes is further increased by alternative splicing of transcripts. Cloned cDNAs for two of these isoforms have been used as probes to localize chromosomally the human PMCA1 (ATP2B1) gene to 12q21-q23 and PMCA4 (ATP2B2) to 1q25-q32. These results were obtained by three independent methods, including Southern analysis of human-rodent somatic cell hybrids, in situ hybridization of human metaphase spreads, and genetic linkage analysis in the CEPH pedigrees. High-frequency RFLPs detected at each locus were used in these linkage analyses. No evidence was obtained for multiple copies of the gene at either locus. A cross-hybridizing sequence was detected with PMCA4 probes on Xq13-qter at low stringency. Further studies are required to determine whether this X-chromosomal sequence represents a third member of the PMCA gene family.

Blotting, Southern↗
PubMed1991

Cell attachment activity of cementum proteins and mechanism of endotoxin inhibition.

Cementum occupies a unique anatomical location where soft connective tissues of the periodontium are attached to root surfaces. Cell attachment properties of proteins present in cementum were studied. Human and bovine cementum were extracted with 0.5 mol/L CH3COOH followed by 4 mol/L guanidine, and proteins were separated by ion-exchange chromatography and SDS-polyacrylamide gel electrophoresis. Cells were labeled with radioactive amino acids and added to tissue-culture plastic plates incubated with cementum proteins, and attachment was measured. Results showed that cementum proteins promoted the attachment of smooth muscle cells, endothelial cells, and fibroblasts, but not epithelial cells. Fibroblasts attached more efficiently than other cell types, and they manifested spreading with re-organization of actin filaments. No attachment occurred to plates incubated with endotoxin from A. actinomycetemcomitans. Fewer fibroblasts attached to plates treated with cementum proteins in the presence of endotoxin, but cells pre-treated with endotoxin attached normally. Attachment was not inhibited when plates were incubated first with attachment proteins and then with endotoxin; however, it was decreased when endotoxin or bovine serum albumin preceded cementum proteins. Cementum proteins with Mr 68,000, 61,000, 55,000, and 36,000 (p68, p61, p55, and p36, respectively) manifested attachment activity, while protein(s) with Mr 23,000-24,000 did not. Western blots revealed that guanidine extracts contained three bands cross-reacting with anti-bovine sialoprotein-II antibody, but the p61, p55, and p36 were negative. We conclude that cementum contains bovine sialoprotein-II and at least four other fibroblast attachment proteins, and that they do not support epithelial cell attachment.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1991

Penetrating injuries to the stomach.

The charts of 298 consecutive patients with penetrating gastric injuries were reviewed. Mechanisms of injury were gunshot wounds in 167, stab wounds in 107 and shotgun wounds in 24. Twenty-eight patients died within 24 hours and 27 patients had serosal injuries. These patients were excluded from the study. The morbidity of gastric injury was defined in 243 patients. The probability of morbidity from the gastric wound was assessed by a multivariate analysis of 11 factors, including number of associated injuries, amount of contamination, age, mechanism of injury, shock, thoracostomy tube, injury to operation time, operative time, blood replacement and injury to the diaphragm or colon. Extensive complications developed in 65 patients. Eleven patients died. The gastric injury was directly associated with 15 extensive complications: ten instances of empyema after gastric and diaphragmatic injuries, two instances of gastric repair breakdown, gastric repair bleeding requiring exploration, a missed gastric injury and one instance of gastric outlet obstruction. One patient died of sepsis after breakdown of the gastric repair. Complications were statistically associated with age, gunshot wounds and the use of 2 or more units of blood. Other factors did not statistically increase complications. The 12.5 per cent empyema rate (ten of 81 patients) with gastric and diaphragmatic wounds was unexpected, but not statistically significant. Morbidity from penetrating gastric injuries is secondary to technical and infectious complications. Age, mechanism of injury and blood transfusion correlated with morbidity. The increased incidence of empyema suggests consideration of pleural lavage in combined gastric and diaphragmatic injuries.

Chi-Square Distribution↗
PubMed1990

Absence of placebo response in obsessive-compulsive disorder.

Analyses in 30 patients with a diagnosis of obsessive-compulsive disorder given single-blind placebo over a 2-week period and of 12 of these patients who continued treatment on double-blind placebo for an additional 10 weeks revealed virtual absence of improvement on both clinician and self-rating scales of obsessions, compulsions, phobias, depression, and anxiety. This result would imply that the contribution of the placebo effect to the pharmacotherapy of patients with obsessive-compulsive disorder is negligible although considerable effort and work is still required to reliably identify one of four panic disorder with agoraphobia patients who respond to placebo. The placebo response thus presents a clear distinction between these two phenomenologically complex anxiety disorders.

Adolescent↗
PubMed1990

Combined entrapment of the median and anterior interosseous nerves in a pediatric both-bone forearm fracture.

Unrecognized entrapment of the median nerve and its anterior interosseous branch in the midportion of the forearm occurred in a 12-year-old girl following reduction of a closed both-bone fracture. Following delayed diagnosis, treatment required secondary neurolysis and microscopic neurorrhaphy. Meticulous prereduction and postreduction neurovascular examination is recommended to prevent this unique complication.

Child↗