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K Olson

Publications and source records attributed to K Olson.

14 recordsLinked to original sources
PubMed1992

Large, identical, tandem repeating units in the C protein alpha antigen gene, bca, of group B streptococci.

Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in the United States. The surface-associated C protein alpha antigen of GBS is thought to have a role in both virulence and immunity. We previously cloned the C protein alpha antigen structural gene (named bca for group B, C protein, alpha) into Escherichia coli. Western blots of both the native alpha antigen and the cloned gene product demonstrate a regularly laddered pattern of heterogeneous polypeptides. The nucleotide sequence of the bca locus reveals an open reading frame of 3060 nucleotides encoding a precursor protein of 108,705 Da. Cleavage of a putative signal sequence of 41 amino acids yields a mature protein of 104,106 Da. The 20,417-Da N-terminal region of the alpha antigen shows no homology to previously described protein sequences and is followed by a series of nine tandem repeating units that make up 74% of the mature protein. Each repeating unit is identical and consists of 82 amino acids with a molecular mass of 8665 Da, which is encoded by 246 nucleotides. The size of the repeating units corresponds to the observed size differences in the heterogeneous ladder of alpha C proteins expressed by GBS. The C-terminal region of the alpha antigen contains a membrane anchor domain motif that is shared by a number of Gram-positive surface proteins. The large region of identical repeating units in bca defines protective epitopes and may play a role in generating phenotypic and genotypic diversity of the alpha antigen.

Amino Acid Sequence↗
PubMed1992

Skin temperature biofeedback: evaluation of non-clinical children's responses.

The present study evaluated the extent to which children are able to learn to increase skin temperature with biofeedback training. Forty-nine children (ages 7-16) were randomly assigned to either standard biofeedback, novel biofeedback or control groups, which met for 16, 16, and 5 sessions, respectively. Results indicated children in the novel biofeedback group significantly increased their skin temperature as compared with the control group. The biofeedback groups exhibited significant skin temperature control during feedback. Results provide normative data on what to expect from children receiving skin temperature biofeedback.

Adolescent↗
PubMed1991

Angiographic follow-up and clinical outcome of 126 patients after percutaneous directional atherectomy (Simpson AtheroCath) for occlusive peripheral vascular disease.

Angiographic and clinical follow-up data were obtained in 115/126 patients who underwent directional atherectomy for peripheral vascular disease; of the 126, ten were excluded for appropriate reasons and one was lost to follow-up. Thus, 115/116 successful atherectomy patients (99%) had follow-up of 182/213 lesions (86%): 74 patients (64%) with angiography (mean time 5.4 mon), and 41 patients (36%) clinically. One hundred twenty-eight of 183 lesions (70%) had angiographic follow-up; the lesion recurrence as a stenosis or as an occlusion was 53%. Lesion distribution did not differ between angiography and clinical follow-up groups: nearly 85% were within the superficial femoral or popliteal arteries. Despite data stratification, angiographic follow-up indicated that patients after successful directional atherectomy, at a mean follow-up time of 5 mos, have more than a 50% lesion recurrence rate. Although directional atherectomy (Simpson AtheroCath) utilizing present techniques has excellent primary success and acceptable complication rates, angiographic follow-up statistics are bothersome.

Aged↗
PubMed1991

Acute angiographic and clinical outcome of high speed percutaneous rotational atherectomy (Rotablator).

Percutaneous rotational atherectomy (Rotablator), a high speed (greater than 100,000 RPM) rotational burr, was used successfully in 38 of 43 patients (88%) (mean age: 65 +/- 7 years) with 82 lesions (71 stenoses and 11 occlusions). The clinical indications were claudication (84%), nonhealing ulcer (7%), and renovascular hypertension (7%). Rotablation was successful in 78 of 82 lesions (95%): 68 of 71 (96%) stenoses (12 of 12 iliac, 11 of 11 femoral, 7 of 8 popliteal, 36 of 37 tibial, and 2 of 3 renal arteries; 60% of lesions were diffuse, i.e., greater than or equal to 4 cm in length), and 10 of 11 (91%) occlusions (5 of 6 femoral, 1 of 1 popliteal, 3 of 3 tibioperoneal, 1 of 1 brachial artery). The Rotablator significantly (p less than 0.001) reduced the arterial obstruction (stenoses: 85 +/- 11% to 12 +/- 12%); occlusions: 100% to 25 +/- 10%). The effective final burr size for arteries varied at 3.5-4.5 mm for renal, 3.0-3.5 mm for femoral, and 2.0-3.0 mm for brachial and tibial. Complications included gross hemoglobinuria without sequelae in 27 patients (63%), groin hematoma in 10 (23%), arterial spasm in 10 (23%), and arterial bypass in 2 (5%). The Rotablator was successfully used, without concomitant conventional balloon angioplasty, to open arterial lesions with excellent angiographic results in both diffuse and segmental peripheral vascular disease. There was gratifying patient clinical improvement.

Aged↗
PubMed1977

Methotrexate compared with placebo in lung cancer.

Two hundred thirty-nine patients with microscopically proven, inoperable bronchogenic carcinoma were allocated at random to receive twice weekly I.M. injections of either methotrexate at "high dose" of 0.06 mg/kg/dose or methotrexate at "low dose" of 0.2 mg/kg or visually indistinguishable placebo in the same volume of 0.1 ml/kg for four months. Twelve patients were invalidated for procedural reasons. Objective response (greater than or equal to 50% tumor regression) was dose-related with 21% of 48 patients with measurable disease on high -ose, 11% of 37 patients on low dose, and 6% of 32 patients on placebo. Corresponding response rates for epidermoid carcinoma were 35% of 23 patients, 9% of 11 patients, and 0 of 13 patients. Responders in the two treatment groups had a three to four fold increase of median survival (p less than .05). Non-responders on high and low dose methotrexate lived as long as patients on placebo. Leukopenic patients in all three treatment groups lived substantially longer than patients without leukopenia less than 4,500/mm3, irrespective of presence or absence of objective response. All three regimens were well tolerated. None of the patients had life-threatening toxicity. It is concluded that methotrexate at "high dose" is a potentially useful drug for temporary palliation of epidermoid carcinoma of the lung.

Adenocarcinoma↗
PubMed1976

Intracavitary bleomycin in the management of malignant effusions.

Instilled bleomycin and thoracostomy were utilized in 38 patients with malignant pleural effusions; the therapy produced a complete or partial response rate of 63%. Toxicity was minimal. In patients with intraperitoneal effusions, bleomycin instillation after drainage produced a complete or partial response in 36%. One patient had severe hypotension and fever. Patients with ovarian and breast carcinoma responded best, among them, effusions were controlled in greater that 70%. Because of its low systemic toxicity, absence of marrow toxicity, and virtual absence of discomfort, we think that the local instillation of bleomycin is indicated in the management of malignant effusions.

Ascites↗
PubMed1975

Enzymatic multiplication of a chemically synthesized DNA fragment.

A synthetic DNA fragment of 19 residues was enlarged by the enzymatic addition of deoxyadenylate residues to its 3'-end with calf thymus terminal deoxynucleotidyl transferase. The 3'-terminus of this elongated DNA strand was blocked with 2', 3'-dideoxyadenylate to prevent hydrolysis by the 3'-exonuclease function of E. coli DNA polymerase I. This elongated and 3'-blocked fragment was annealed to an oligomeric primer and used as a template for the synthesis of a complementary copy of the synthetic 19-mer. The product of such a repair synthesis was separated by gel filtration and analyzed by nearest neighbor techniques. All template strands were copied with complete repair in over 90% of the chains. Facile recovery of the elongated template by virtue of its size permitted repetition of the copy process, thus allowing accumulation of the desired strand.

Animals↗
PubMed1975

Determination of the 3' terminal nucleotide of DNA fragments.

A new method for determining the 3'-terminal nucleotide of a DNA strand is presented. Use is made of the fact that one (and only one) 2',3'-dideoxyribonucleotide can be added to the 3'-end of a DNA fragment with calf thymus terminal transferase. Addition of more than one nucleotide analog per strand is impossible due to the absence of a 3'-terminal hydroxyl group. If the terminatind dideoxyribonucleotide contains an (alpha 32p) label, the resulting 3'-blocked strand can be digested by "nearest neighbor" techniques and the original 3'-endgroup determined. Picomole quantities of DNA strands can be labeled and the 3'-end determined.

Animals↗
PubMed1975

Differential reinforcement and signal detection.

Reinforcement was introduced for responses normally treated as errors in signal-detection procedures. The first experiment used a standard two-response discrete-trial procedure with no reinforcement for errors. Results showed that rats altered their response biases but maintained constant sensitivity to visual signals when reinforcement probabilities varied, and that their sensitivity depended on the physical difference between signals, in accordance with the predictions of signal-detection theory. Experiment II, with rats, and Experiment III, with pigeons, demonstrated that sensitivity decreased in this procedure when reinforcement was scheduled for errors with the signals held constant, despite independence of overall number of reinforcers and sensitivity. Experiment IV, with rats, replicated the decrease in sensitivity in a continuous procedure employing only one response. The decrements in sensitivity were similar across Experiments II, III, and IV, and accorded well with earlier research. Thus, contrary to a fundamental assumption of signal-detection theory, estimates of sensitivity are not always invariant with respect to the outcomes of responding, but depend on relative reinforcement of correct responses.

Animals↗