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Biomedical subjects

R S Nelson

Publications and source records attributed to R S Nelson.

At least 55 records · Page 3Linked to original sources
PubMed1983

Effects of fenbufen, indomethacin, naproxen, and placebo on gastric mucosa of normal volunteers. A comparative endoscopic and photographic evaluation.

The effects of fenbufen (1,000 mg a day), indomethacin (150 mg a day), naproxen (750 mg a day), and placebo on gastric mucosa were determined by endoscopy and recorded photographically. One hundred normal subjects, randomly divided into equal, parallel-treatment groups, were given the drugs in divided daily doses for seven consecutive days. The results revealed that the effects of fenbufen on gastric mucosa were significantly (p less than or equal to 0.05) less than those of either naproxen or indomethacin and not statistically different from those observed with placebo.

Adult↗
PubMed1983

The role of the mannose/N-acetylglucosamine receptor in the pinocytosis of horseradish peroxidase by mouse peritoneal macrophages.

Saccharomyces cerevisiae mannan inhibits the pinocytosis of horseradish peroxidase (HRP) by resident, thioglycollate-,proteose peptone-, and Corynebacterium parvum-elicited macrophages from 30 to 70% when 1 mg/ml HRP is used, and 65 to 87% when 250 micrograms/ml HRP is used. In contrast, HRP uptake by J774 cells, a macrophage cell line reported to have little mannose receptor activity, is inhibited only about 25% by mannan. HRP uptake by resident and thioglycollate-elicited (thio) macrophages is also inhibited 34 and 66% by addition of EGTA to the medium and 55 and 79% by trypsin treatment of the macrophages, respectively. The inhibitory effect of EGTA can be reversed by 1 mM excess Ca2+. High extracellular concentrations of Ca2+, in the range of 10-20 mM, however, inhibit pinocytosis in resident macrophages by about 50%. Sucrose uptake by resident macrophages is not appreciably affected by mannan. These results support the hypothesis that HRP uptake is mediated by the macrophage mannose/N-acetylglucosamine receptor. PMA stimulates fluid-phase pinocytosis of HRP by thio macrophages but does not affect receptor-mediated uptake of HRP, while the combination of adenosine, homocysteine, and erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) selectively inhibits bulk-phase uptake by thio macrophages.

Animals↗
PubMed1983

Thrombocytopenia and gastrointestinal hemorrhage in the cancer patient: prevalence of unmasked lesions.

Some coagulation deficiencies are known to cause bleeding by unmasking existing gastrointestinal pathology, as opposed to directly causing mucosal blood loss. Characteristics and etiology of gastrointestinal hemorrhage associated with thrombocytopenia have not been analyzed. Our objectives were to correlate the distribution and cause of gastrointestinal bleeding, as diagnosed by fiberoptic endoscopy, with the severity of thrombocytopenia. One hundred thirty-three patients were divided into three groups, determined by platelet count at the time of bleeding (group A: less than 20,000/mm3; group B: 20,000 to 40,000/mm3; group C greater than 40,000/mm3). Results of 187 endoscopies revealed unifocal sources of blood loss in over 50% of each group, and diffuse mucosal oozing independent of gastrointestinal pathology was seen in only 1% of group C. The only significant difference (p = 0.04) comparing unifocal, multifocal, and diffuse sources of bleeding was observed between groups A and C, where in the distribution of multifocal or diffuse sources of bleeding was more common in group A. Esophagitis was more common and gastric ulceration less common in group A. No endoscopic complications occurred. Gastrointestinal bleeding associated with thrombocytopenia is most commonly due to co-existent gastrointestinal pathology as opposed to diffuse mucosal bleeding. Even when an inflammatory process, such as esophagitis or gastritis, affects a particular organ, bleeding is usually unifocal or multifocal as opposed to diffuse even in the presence of moderately severe thrombocytopenia.

Endoscopy↗
PubMed1983

Gastrointestinal hemorrhage in the cancer patient.

The usefulness of fiberoptic endoscopy, performed to identify the cause(s) of gastrointestinal bleeding in cancer patients was assessed by (1) identifying the clinical presentation of bleeding, (2) evaluating the safety and diagnostic yield of fiberoptic endoscopy, (3) determining the frequency distribution of causes of bleeding, and (4) evaluating the clinical course following acute gastrointestinal bleeding in a cancer patient population. Hematemesis, melena, and hematochezia were observed in decreasing order of frequency as manifestations of bleeding. Of 187 endoscopic procedures performed on 133 patients, 75% were bleeding from benign lesions with the majority due to gastric ulceration, gastritis, or duodenal ulceration. One third of patients with tumors involving the gastrointestinal tract were bleeding from another source. Mortality from major hemorrhage was 8%; 55% of patients were alive at the end of 2 years. Endoscopy was performed without complications and contributed to medical management, angiographic therapy, and surgical planning.

Endoscopy↗
PubMed1983

Yeast mannans inhibit binding and phagocytosis of zymosan by mouse peritoneal macrophages.

We have examined the effects of various mannans, glycoproteins, oligosaccharides, monosaccharides, and sugar phosphates on the binding and phagocytosis of yeast cell walls (zymosan) by mouse peritoneal macrophages. A phosphonomannan (PO(4):mannose ratio = 1:8:6) from kloeckera brevis was the most potent inhibitor tested; it inhibited binding and phagocytosis by 50 percent at concentrations of approximately 3-5 mug/ml and 10 mug/ml, respectively. Removal of the phosphate from this mannan by mild acid and alkaline phosphatase treatment did not appreciably reduce its capacity to inhibit zymosan phagocytosis. The mannan from saccharomyces cerevisiae mutant LB301 inhibits phagocytosis by 50 percent at 0.3 mg/ml, and a neutral exocellular glucomannan from pichia pinus inhibited phagocytosis by 50 percent at 1 mg/ml. Cell wall mannans from wild type S. cervisiae X2180, its mnn2 mutant which contains mannan with predominantly 1(arrow)6- linked mannose residues, yeast exocellular mannans and O-phosphonomannans were less efficient inhibitors requiring concentrations of 1-5 mg/ml to achieve 50 percent reduction in phagocytosis. Horseradish peroxidase, which contains high-mannose type oligosaccharides, was also inhibitory. Mannan is a specific inhibitor of zymosan binding and phagocytosis. The binding and ingestion of zymosan but not of IgG- or complement-coated erythrocytes can be obliterated by plating macrophages on substrates coated with poly-L-lysin (PLL)-mannan. Zymosan uptake was completely abolished by trypsin treatment of the macrophages and reduced by 50-60 percent in the presence of 10 mM EGTA. Pretreatment of the macrophages with chloroquine inhibited zymosan binding and ingestion. These results support the proposal that the macrophage mannose/N-acetylglucosamine receptor (P. Stahl, J.S. Rodman, M.J. Miller, and P.H. Schlesinger, 1978, Proc. Natl. Acad. Sci. U.S.A. 75:1399-1403, mediates the phagocytosis of zymosan particles.

Animals↗
PubMed1983

Collagenous colitis.

Collagenous colitis is a newly described entity that clinically manifests itself as watery diarrhea of long-standing duration. The main histopathologic characteristic is the presence of a collagen band immediately beneath the colonic surface epithelium. Ultrastructurally, the collagen is deposited beneath the basement membrane, which is intact. Pathogenetically, an aberrant function of the pericryptal fibroblastic sheath may be involved.

Cathartics↗
PubMed1983

Soybean mutants lacking constitutive nitrate reductase activity : I. Selection and initial plant characterization.

The objectives of this study were to select and initially characterize mutants of soybean (Glycine max L. Merr. cv Williams) with decreased ability to reduce nitrate. Selection involved a chlorate screen of approximately 12,000 seedlings (progeny of mutagenized seed) and subsequent analyses for low nitrate reductase (LNR) activity. Three lines, designated LNR-2, LNR-3, and LNR-4, were selected by this procedure.In growth chamber studies, the fully expanded first trifoliolate leaf from NO(3) (-)-grown LNR-2, LNR-3, and LNR-4 plants had approximately 50% of the wild-type NR activity. Leaves from urea-grown LNR-2, LNR-3, and LNR-4 plants had no NR activity while leaves from comparable wild-type plants had considerable activity; the latter activity does not require the presence of NO(3) (-) in the nutrient solution for induction and on this basis is tentatively considered as a constitutive enzyme. Summation of constitutive (urea-grown wild-type plants) and inducible (NO(3) (-)-grown LNR-2, LNR-3, or LNR-4 plants) leaf NR activities approximated activity in leaves of NO(3) (-)-grown wild-type plants. Root NR activities were comparable in wild-type and mutant plants grown on NO(3) (-), and roots of both plant types lacked constitutive NR activity when grown on urea. In both growth chamber- and field-grown plants, oxides of nitrogen [NO((x))] were evolved from young leaves of wild-type plants, but not from leaves of LNR-2 plants, during in vivo NR assays. Analysis of leaves from different canopy locations showed that constitutive NR activity was confined to the youngest three fully expanded leaves of the wild-type plant and, therefore, on a total plant canopy basis, the NR activity of LNR-2 plants was approximately 75% that of wild-type plants. It is concluded that: (a) the NR activity in leaves of NO(3) (-)-grown wild-type plants includes both constitutive and inducible activity; (b) the missing NR activity in LNR-2, LNR-3, and LNR-4 leaves is the constitutive component; and (c) the constitutive NR activity is associated with NO((x)) evolution and occurs only in physiologically young leaves.

Journal Article↗
PubMed1983

Soybean Mutants Lacking Constitutive Nitrate Reductase Activity : II. Nitrogen Assimilation, Chlorate Resistance, and Inheritance.

Nitrogen assimilation in three nitrate reductase (NR) mutants of soybean (Glycine max L. Merr. cv Williams) was studied in the growth chamber and in the field. These mutants, LNR-2, LNR-3, and LNR-4, lack the non-NO(3) (-)-inducible or constitutive fraction of leaf NR activity found in wild-type plants, but this had no effect on the concentration of nitrogen accumulated when grown on NO(3) (-) in the growth chamber. Dry weight accumulation of two of the mutants (LNR-3 and LNR-4) was decreased relative to LNR-2 and wild type. In the field, LNR-2 had dry weights and nitrogen concentrations similar to the wild type at 34 and 61 days after planting, and at maturity. Acetylene reduction activities were also similar at 61 days.Urea-grown LNR-2 seedlings lack both inducible and constitutive NR activity, and were resistant to four days of treatment with 0.5 mm ClO(3) (-). Urea-grown wild-type seedlings, having only constitutive NR activity, developed ClO(3) (-) toxicity symptoms and suffered decreases in unifoliolate leaf NR activity and chlorophyll concentration. This suggests that (a) the reduction of ClO(3) (-) to ClO(2) (-) by NR is the major cause of ClO(3) (-) toxicity in soybeans and (b) the constitutive NR is active in situ.Segregation of the F(2) of reciprocal crosses between the wild type and the mutants indicated that absence of constitutive NR activity was controlled by a single recessive nuclear gene. Evolution of NO((x)) gas was also absent in these mutants, and this was found to be inherited jointly with constitutive NR activity: in 346 segregants, no recombinants were found. Allelism tests between LNR-2 and LNR-3, and LNR-2 and LNR-4, indicated that the constitutive NR mutation was at the same locus in each mutant.

Journal Article↗
PubMed1982

The Isocon camera system in digital subtraction imaging.

A new system for digital vascular subtraction imaging is presented. The image receptor consists of a rare-earth screen with light output optically focused onto the photocathode of a low-light-level image Isocon camera. This system represents a departure from the conventional use of the image intensifier for digital subtraction imaging. Our initial results suggest that this system could be competitive with traditional image intensifier systems and that it deserves clinical trial.

Angiography↗
PubMed1981

Colorectal cancer in young adults.

The clinical and pathologic characteristics of colorectal cancer in patients younger than 30 years are compared with those in patients 30 to 39 years of age. Patients in the two age groups had similar symptoms, predominantly undifferentiated neoplasms, and poor prognoses. However, when the characteristics of these patients were compared with those described for a general patient population with colorectal cancer there was a gradual decrease in the incidence of mucin-producing tumors, poorly differentiated carcinomas, and primary lesions in the right colon, with increasing age at diagnosis. The highest incidences were found in patients less than 30 years old. The degree of tumor anaplasia and stage of tumor at diagnosis significantly influenced the duration of disease-free interval after curative resection of the primary and the duration of survival. Ninety-six percent of patients younger than 40 years had carcinomas extending beyond the colonic wall at diagnosis, adversely affecting long-term survival. The five-year survival of only 25% to 30% in these patients emphasizes the need for early diagnosis and aggressive treatment.

Adolescent↗
PubMed1981

Color television in gastrointestinal endoscopy.

Endoscopic color television is a practical method of recording gastrointestinal pathology and procedures. Nevertheless, a careful MEDLARS review of the medical literature failed to reveal a mention of this method during the past ten years. The endoscopic procedure can be recorded to illustrate many features not possible with still pictures. While particularly useful in teaching endoscopy, it is also useful for demonstrating pathologic findings to interested physicians, patients, and relatives. Television recording requires meticulous attention to details of lighting, focus, and cleansing of areas to be photographed and of the instrument objective, but results may well be superior to other means of photography in gastrointestinal endoscopy.

Color↗
PubMed1981

A comparative endoscopic evaluation of the damaging effects of nonsteroidal anti-inflammatory agents on the gastric and duodenal mucosa.

Twenty-five normal volunteers were randomized into five equal parallel groups. Groups I received ibuprofen (2,400 mg./day); group II received tolmetin (2,000 mg./day); group III received indomethacin (150 mg./day); group IV received naproxen (750 mg./day) and group V received placebo (four tablets daily). All drugs were given on a q.i.d. basis except naproxen which was given b.i.d. The doses selected represented the manufacturer's highest recommended dosage for the treatment of arthritic disorders. A single-blind technic was used in which the investigators were unaware of which drug each volunteer was taking. Upper gastrointestinal endoscopy and photography were carried out before and after seven days of administration of each medication. Gastric and duodenal mucosal injury was graded on a 0-4 + scale. Three of the four drugs studied produced essentially equal gastric and duodenal mucosal injury with tolmetin producing the most damage followed by naproxen and indomethacin. Ibuprofen produced gastric mucosal injury equivalent to that seen with naproxen and indomethacin but no duodenal mucosal injury was seen with this drug. Extremely poor correlation was found between subjective symptomatology and endoscopic findings.

Adult↗
PubMed1981

Endoscopic upper gastrointestinal polypectomy. Report of 73 polypectomies in 63 patients.

Seventy-three upper gastrointestinal endoscopic polypectomies were performed in 63 patients over a period of five years. Thiry-eight patients (52%) had adenomatous polyps, two of which contained carcinoma in situ and 26 (36%) were inflammatory in nature. Four lesions were removed from the duodenum. Hemodynamically significant hemorrhage occurred in five cases and persistent symptomatic ulcer in three cases. All complications occurred early in the series and responded to conservative measures. There was no mortality or need for surgical intervention in any case. It was concluded that: 1. upper gastrointestinal tract endoscopic polypectomy is a safe and relatively simple procedure; 2. postprocedural complications can be markedly reduced by prophylactic conservative antiulcer therapy and 3. especially in the area of adenomatous polyps, excision of the entire lesion is superior to biopsy in the detection of early malignancy.

Adenoma↗
PubMed1980

Sarcoma of the stomach: clinicopathologic study of 43 cases.

The records of 43 patients with histologically proved primary gastric sarcoma treated at M. D. Anderson Hospital and Tumor Institute between 1945 and 1975 were reviewed. Weight loss, abdominal pain, and hematemesis or melena were the most common symptoms, and palpable epigastric mass was the most common physical sign. Ninety-five percent of the gastric tumors were leiomyosarcomas. The median survival time and the five-year survival for the 29 patients who had curative gastrectomy were 33 months and 38%, respectively. Morphologic and histologic factors that adversely influenced the length of disease-free interval and survival following curative surgery included 1) primary tumor 8 cm or greater in diameter, 2) tumor extension to serosa of the stomach, and 3) low grade of differentiation of the primary tumor. Seventy-seven percent of recurrences in patients with curative tumor resection occurred within two years of resection of the primary. Of the 17 patients with advanced disease who received chemotherapy, two (15%) had objective tumor regression of greater a median survival time of eight months for patients who failed to respond. New approaches that may improve the results of treatment of gastric sarcoma are discussed.

Female↗
PubMed1980

Nonoperative management of persimmon bezoar. A successful modification of traditional papain therapy.

The soft phytobezoars occurring in the postoperative stomach may be readily removed by enzyme digestion and manipulation. In contrast, the persimmon bezoar (diospyrobezoar) has been persistently to such treatment and has required surgical removal. Experience with unsuccessful attempts at enzyme digestion in a number of such patients led to the experimental use of a "soaking" technic which satisfactorily dissolved two of three large persimmon bezoars and shrank the remaining foreign body sufficiently so that it could be removed endoscopically by way of the esophagus. A concomitant gastric ulcer healed uneventfully on medical therapy.

Aged↗