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Biomedical subjects

S Fields

Publications and source records attributed to S Fields.

At least 127 records · Page 7Linked to original sources
PubMed1988

Yeast STE7, STE11, and STE12 genes are required for expression of cell-type-specific genes.

Cell type specialization in yeast haploids involves the mutually exclusive expression of one of two sets of genes, the a-specific and alpha-specific genes. We demonstrated that the products of the STE7, STE11, and STE12 genes were required for the expression of both gene sets. RNA levels transcribed from these gene sets were significantly decreased but not abolished in haploids containing a null mutation in the STE7, STE11, or STE12 gene. Transcript levels from the a- and alpha-specific gene sets were not further reduced in strains harboring mutations in all three STE genes, suggesting that STE7, STE11, and STE12 are required for the same aspect of transcription. We further showed that the requirement for these products was not the same for each member of a particular gene set. However, for any given a- or alpha-specific gene, the effect on RNA levels of any of the three ste mutations was similar.

Genes↗
PubMed1988

Widespread Castleman disease: CT and US findings.

The widespread form of Castleman disease is a rare condition that has been recognized only recently as a disease with an aggressive, often malignant course. The authors present computed tomographic (CT) findings in six patients with this condition and ultrasound (US) findings in four of the six. CT demonstrated splenomegaly and retroperitoneal lymphadenopathy in all six patients. In one patient, CT also showed additional widespread mesenteric and peripancreatic lymphadenopathy, a large mesenteric mass adherent to the descending colon in another, and mediastinal lymphadenopathy in a third. Three patients had peripheral axillary or inguinal lymphadenopathy. Enlarged lymph nodes were 1-4 cm in diameter, and none displayed contrast enhancement on CT scans obtained with drip infusion of contrast media. On US scans, the nodes were poorly echogenic in all four cases. In no case was focal liver or splenic infiltration seen on either CT or US scans.

Adolescent↗
PubMed1988

Amiodarone pulmonary toxicity presenting as a solitary lung mass.

Following treatment with amiodarone, a patient developed weight loss, fatigue and severe myopathy, without respiratory symptoms. A solitary lung infiltrate, impaired thyroid and liver function tests, and leukocytosis were evident. Biopsies from the lung lesion, liver, and bone marrow revealed foam cells. All these signs and symptoms subsided following cessation of amiodarone therapy. It is demonstrated that amiodarone may induce a localized lung lesion rather than diffuse pulmonary disease.

Aged↗
PubMed1988

Exercise conditioning in the rehabilitation of patients with chronic obstructive pulmonary disease.

Fifty-nine patients with severe chronic obstructive pulmonary disease (COPD) performed pulmonary function and exercise tests before and after participation in a 12-day pulmonary rehabilitation inpatient program. Postdischarge follow-ups were performed at three months. Training consisted of twice daily aerobic exercise of 30 to 40 minutes' duration. Intensity of training was determined after exercise testing and approached the maximal limits of ventilation. In general, the program failed to demonstrate significant changes in pulmonary function. Exceptions were mid-expiratory flow rate (FEF25-75) (p less than .02) and peak flow rate (p less than .05). Evaluation of exercise capacity via maximal exercise testing yielded significant increases in caloric expenditure (p less than .001), peak exercise oxygen consumption (p less than .001), and work output (p less than .0001). Peak exercise ventilation increased significantly (p less than .005) due to an increase in tidal volume (p less than .002). Work efficiency improved with training, but the change was not statistically significant. Resting oxygen consumption and carbon dioxide production were decreased (p less than .05); tidal volume was increased (p less than .005). However, the significant increase noted in tidal volume did not alter minute ventilation. In general, the changes noted at 12 days were maintained at three months postdischarge. These data support the hypothesis that a short-term, in-hospital program of general exercise conditioning can improve work output, gas exchange, and mechanical efficiency without significantly affecting spirometric indices. These changes may translate into improved performance of activities of daily living and a sense of general well-being.

Efficiency↗
PubMed1987

Regulation by the yeast mating-type locus of STE12, a gene required for cell-type-specific expression.

The STE12 gene of the yeast Saccharomyces cerevisiae is necessary for RNA synthesis from two sets of cell-type-specific genes. We isolated a recombinant plasmid that carries the STE12 gene by complementation of the mating defect of ste12 cells. The DNA of the cloned gene was used to disrupt the chromosomal STE12 gene and to identify the STE12 transcript. We show that the STE12 transcript level is repressed 5- to 10-fold in a/alpha cells. The STE12 product thus acts to promote diploidy by activating expression of the two sets of genes necessary for mating, and then its synthesis is repressed by products unique to the diploid cell type.

Cell Differentiation↗
PubMed1987

Predicting maximal exercise ventilation in patients with chronic obstructive pulmonary disease.

Shortness of breath is a chief complaint of many individuals with cardiopulmonary diseases. Exercise testing is often used to help differentiate cardiac from pulmonary involvement. In assessing pulmonary dysfunction during exercise it is essential to know the point at which ventilatory limitation will occur. Numerous authors have presented regression equations based on the FEV1 for predicting either MVV or VEmax. Resting pulmonary function studies were obtained from 53 patients with COPD. Symptom-limited maximal exercise testing was completed on a cycle ergometer using increments of 10 watts/min. Each regression equation for predicting MVV or VEmax was then applied to the data set. Results showed that the FEV1 correlated with the measured VEmax (r = .81) as did PEF (r = .81), MVV (r = .78), IC (r = .78), DCO (r = .68), VA (r = .67), VE (r = .65) and FVC (r = .64). Single post-bronchodilator FEV1 measurements ranged from 0.56 to 1.64 L (mean 1.0 L) while VEmax ranged from 16 to 78 L/min (mean 37.69 L/min). The equation VEmax = 37.5 X FEV1 was the most robust equation found in the literature for predicting VEmax in this sample. This equation was not statistically different from the line of identity when predicted VEmax was plotted against the measured VEmax. The intercept was 0.91 with a slope of 0.98. In addition, this equation had a smaller mean square error in predicting VEmax than those of the other equations investigated.

Adult↗
PubMed1987

Osteolytic osteogenic sarcoma of ilium in 46-month-old boy.

A 46-month-old boy with a four-day history of pain and swelling over the right posterior ilium was thought to have acute osteomyelitis on the basis of a normal pelvic x-ray, markedly increased scintigraphic activity in the right ilium, and a mildly elevated sedimentation rate. At surgery, no signs of osteomyelitis were found, and biopsy revealed osteolytic osteogenic sarcoma. This is the youngest child with osteogenic sarcoma of the pelvic reported in the literature.

Bone Neoplasms↗
PubMed1986

Computed tomography prior to surgery for ovarian carcinoma.

The value of investigation of patients with ovarian carcinoma by preoperative computed tomography scan was evaluated in all the patients operated on during the last 2 years; 22 patients were included in this study and evaluated. In 11 patients the scan was performed prior to the primary surgery and in the other 11 patients before second look following chemotherapy. CT scan was found to be highly sensitive in detecting ascites, pelvic wall extension and spread or involvement of the uterus. Peritoneal and omental spread was detected in only half of the patients before primary surgery. Prior to second look operation CT scan was effective in excluding liver metastasis, ascites, paraaortic lymph node enlargement, pelvic wall extension and pelvic residual tumour. Generally, CT scan failed to detect peritoneal and omental spread. It is an important tool for preoperative evaluation of the extension of the disease and planning of surgery, but still, the final staging deserves explorative laparotomy.

Altretamine↗
PubMed1986

MRI and CT scan compared with microscopic histopathology in osteogenic sarcoma of the proximal tibia.

The authors report the case of a 15-year-old female who presented with a history of vague but constant pain about the medial aspect of her right knee. X-ray established the presence of an expanding lesion in the medial tibial plateau. Computerized axial tomography (CT) and magnetic resonance imaging (MRI) were used in the evaluation of the lesion. The authors compare the preoperative CT and MRI findings with the microscopic histopathology of the amputation specimen and note that the CT scan underestimated the extent of the microscopic tumor boundaries, whereas MRI showed altered activity beyond these boundaries.

Adolescent↗
PubMed1986

Biopsy of intracranial lesions with computed tomography stereotactic guidance.

Thirteen cases of deep-seated intracranial lesions that were biopsied by the technique of CT (computed tomography) stereotactic guidance are presented. In 11 cases a diagnosis of brain neoplasm was made. One case of a cystic thalamic astrocytoma was treated by stereotactic insertion of a cannula attached to an s.c. reservoir. There was one complication related to a concomitant ventricular catheter placement. The technique is recommended for diagnosis of deep-seated intracranial lesions, where the risk of a conventional open operative approach is considerable.

Adult↗
PubMed1985

The yeast STE12 product is required for expression of two sets of cell-type specific genes.

Yeast alpha and a cells transcribe distinct sets of genes involved in mating behavior, alpha-specific genes and a-specific genes, respectively. The alpha 1 product of the alpha mating type locus (MAT alpha) has been the only known activator of either set of genes; it is required for synthesis of RNA from the alpha-specific genes, one of which is the major alpha-factor gene. By screening for mutants that are no longer able to express this gene, we have identified the STE12 gene product as another positive regulator of the alpha-factor gene. alpha ste12 cells are also defective in RNA production from the other known alpha-specific genes. Moreover, a ste12 cells fail to produce wild-type levels of RNA from the a-specific genes. The STE12 gene product is therefore an activator of two sets of genes involved in yeast cell type specialization.

Genes↗
PubMed1982

Nucleotide sequence of human influenza A/PR/8/34 segment 2.

The nucleotide sequence of RNA segment 2 of human influenza strain A/PR/8/34 has been determined. Segment 2 in 2341 nucleotides long and encodes a protein of 757 amino acids (86,500 daltons molecular weight) which is involved in RNA synthesis. Although segment 2 is identical in size to segment 1, which encodes a protein of related function, neither the nucleotide sequences of these two RNA segments nor the amino acid sequences of the encoded proteins appear to be homologous. The sequence of segment 2 completes the sequence of the virus (total 13,588 nucleotides).

Amino Acid Sequence↗
PubMed1982

Nucleotide sequences of influenza virus segments 1 and 3 reveal mosaic structure of a small viral RNA segment.

Defective interfering RNAs of influenza virus are small segments derived from viral segments 1, 2 and 3. We present here the complete nucleotide sequences of segments 1 and 3 from the human influenza strain A/PR/8/34 and deduce that the sequence of a small RNA segment from A/NT/60/68, apparently a defective interfering RNA, is derived from five separate regions in segment 3 and from one region in segment 1. These regions, which are located near the terminal of the two parental segments, are arranged in the small RNA segment in an alternating fashion: thus a region derived from near 5' terminus is adjacent to a region derived from near a 3' terminus. We propose that the small segment is generated during positive strand synthesis as a result of the viral polymerase pausing at uridine-rich sequences in the template and reinitiating synthesis at another site.

Base Sequence↗