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Biomedical subjects

R A Nelson

Publications and source records attributed to R A Nelson.

At least 127 records · Page 7Linked to original sources
PubMed1976

Pantothenic acid, coenzyme A, and human chronic ulcerative and granulomatous colitis.

To investigate further an apparent relationship between chronic ulcerative and granulomatous colitis and pantothenic acid deficiency, colonic tissues obtained at the time of colectomy in 29 patients with these disorders were assayed for pantothenic acid and for coenzyme A (CoA) activity. For comparison, normal colonic tissues free of pathological lesions were obtained from 31 patients having colectomy for carcinoma or diverticulitis. Plasma, red blood cells, and colonic mucosa were assayed microbiologically for free and total pantothenic acid. The activity of CoA in colonic mucosa was determined by assaying the acetylation of sulfanilamide. Concentrations of free, bound, and total pantothenic acid in blood and in colonic mucosa did not differ between the two groups of patients. Bound pantothenic acid increased linearly with total pantothenic acid. Colonic mucosa concentrated free pantothenic acid to about 50 times the level of blood, and pantothenic acid in red cells was similar to the concentration in plasma. Compared to normal gut mucosa, CoA activity was markedly low in mucosa from patients with chronic ulcerative or granulomatous disease despite the presence of normal amounts of free and bound pantothenic acid. A block in the conversion of bound pantothenic acid to CoA in diseased mucosa is suggested.

Adult↗
PubMed1976

Morphogenesis of bacteriophage phi 29 of Bacillus subtilis: preliminary isolation and characterization of intermediate particles of the assembly pathway.

Three classes of particles have been identified in restrictive phi 29 suppressor-sensitive (sus) mutant infections of Bacillus subtilis, including DNA-containing heads or phage, prohead, and empty heads. Pulse-chase labeling experiments indicate that the prohead, the first particle assembled in 14-infected cells, is converted to DNA-filled heads and phi 29. In addition to the proteins Hd, P10, and F found in mature phi 29, the prohead contains a "core" protein P7 that exits as the prohead matures and appears to recycle during subsequent rounds of prohead assembly. Prohead-like structures accumulate in UV-irradiated cells and are present in restrictive infections with sus mutants of cistrons 9 and 16. Empty heads are observed only when infection results in the formation of DNA-containing particles; this and other evidence indicates that the empty heads are probably not true intermediates. Phage phi 29 assembly apparently occurs by a single pathway in which neck and tail components interact to stabilize the completed DNA-containing head.

Bacillus subtilis↗
PubMed1976

Nocardia infection in a bronchopulmonary sequestration.

A case of intralobar bronchopulmonary sequestration is reported in which the sequestered lung was infected with Nocardia sp. Although recurrent pyogenic infections are common in pulmonary sequestrations, this is the first case report with documented nocardiosis.

Adult↗
PubMed1976

Separation of six bovine complement components and one inactivator (1, 2).

Six components (C1, C5, C6, C7, C8 and C9) of bovine complement and one inactivator (C3 in) could be separated from bovine serum. Bovine C1 was separated by precipitation at low molarity (0.03 M of relative salt concentration) other components by DEAE-cellulose chromatography using 0.005 M sodium phosphate buffer, pH 7.5, as a base for solvents having the relative salt concentration adjusted by addition of NaCl from 0.03 to 0.3 M. The separated bovine complement components could be tested using intermediates formed from sheep erythrocytes, rabbit hemolysin, guinea pig C1 and remaining human complement components. C2, C3 and C4 of bovine origin remained undetected either because of incompatibility with the intermediates used or interference of inhibitors or inactivators.

Animals↗
PubMed1976

Fungus-fermented soybeans benefit the life cycle of Japanese quail (Coturnix coturnix japonica).

Feeding quail chicks diets containing soybeans fermented with two cultures of Aspergilli (A. oryzae N.R.R.L. 451 and A. oryzae N.R.R.L. 506) resulted in significantly superior weight gains (p less than 0.05) through a 4-week growth period and confirmed previous observations made with identical cultures in broiler studies. Subsequent hen-day egg production and egg size were changed little by diets containing fermented soybeans. The numerical increases in fertility and hatchability were not significant. Progeny also responded to the fermented soybean diets, some carry-over effects were evident.

Animal Feed↗
PubMed1976

Transbronchial lung biopsy via the fiberoptic bronchoscope in sarcoidosis.

In a prospective study at two medical centers, 42 consecutive patients with suspected sarcoidosis underwent transbronchial lung biopsy during fiberoptic bronchoscopy. Transbronchial biopsy revealed noncaseating granulomas in 24 of the 38 cases (63%) in which adequate tissue was obtained. Special stains and cultures for acid-fast bacilli and fungi were negative, and sarcoidosis was subsequently diagnosed in all 42 cases. Positive biopsies were obtained in 11 of 20 patients with radiographic stage I disease, in 11 of 15 with stage II disease, and in 2 of 3 with stage III disease. There was a higher probability of a positive biopsy in patients with high symptom scores for cough, wheezing, and dyspnea, and in those with a vital capacity of less than 80% of predicted. The only complication was one small pneumothorax, which spontaneously resolved. Transbronchial lung biopsy is an attractive initial procedure for obtaining histologic confirmation of sarcoidosis.

Adolescent↗
PubMed1976

Total parenteral nutrition.

Total parenteral nutrition (TPN) is a relatively new innovation in patient care which allows us to replace and maintain essential nutrients in patients in whom oral or tube feedings are contraindicated or inadequate. Insertion of a catheter into a large central vein permits one to concentrate hypertonic dextrose calories in normal daily fluid requirements. In addition, TPN solutions contain synthetic amino acids or protein hydrolysates, macroelements, electrolytes, and vitamins. Indications for TPN include intestinal fistulas, severe short bowel syndrome, unresolving pancreatitis, advanced inflammatory bowel disease, delayed postoperative gastrointestinal function, developmental anomalies of the intestinal tract, protracted diarrhea of infancy, and hypermetabolic states. Complications encountered in patients receiving TPN are catheter-related mechanical problems, infections, and metabolic abnormalities. In select patients, who otherwise would require repeated hospitalizations for malnutrition, encouraging results have been achieved by the use of TPN in the home.

Amino Acids↗
PubMed1976

Protein metabolism in the black bear before and during hibernation.

During 3 to 5 months of hibernation, the American black bear does not defecate, urinate, or require food or water. Although the bear loses 15 to 25% of its body weight during this period, there is no significant change in its lean body mass. No net accumulation of the usual nitrogenous products of protein catabolism can be demonstrated in the dormant bear, and there is a decrease in urea production during hibernation. Because of these findings, it has been hypothesized that the black bear can alter its protein metabolism during hibernation by some unknown mechanism. During this study, the metabolis rate of protein turnover in four adult male black bears was measured before, during, and after hibernation, using 125I-labeled serum albumin from black bears as an indicator protein and 14C-labeled leucine as an indicator amino acid. For albumin during both phases, the disappearance rate of labeled albumin from serum was measured over 2 weeks and its turnover rate was calculated from these data. For [14C]leucine, the amino acid was injected during and after hibernation and its appearance in total proteins of plasma was measured. The results using labeled albumin revealed a threefold increase in turnover of protein during hibernation compared with protein turnover before hibernation. Leucine data supported these findings; more labeled leucine was incorporated in plasma proteins during hibernation than in the active state in spring. There were no significant changes in hematocrit, serum albumin concentration, thyroxin, or thyroxine-binding globulin between active and dormant periods, although triiodothyronine tended to decrease during hibernation. We speculate that increased protein turnover suggests a strongly acting protein-anabolic mechanism that would tend to compete with other catabolic pathways for amino acids. Another consequence of this increased protein turnover would be thermogenesis. This may have helped prevent any undue decrease in body temperature. It is notable that the body temperature of the dormant bear is appreciably higher than that of other hibernating animals.

Animals↗
PubMed1975

The detection of the Epstein-Barr virus (EBV) nuclear antigen (EBNA) by anticomplement immunofluorescence. Immunoglobulin class of antibodies and role of complement.

The Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) was detected by anti-complement immunofluorescence (ACIF) in Raji lymphoblastoid cell line, and the mechanism of the reaction explored, using Ig fractions of anti-EBNA sera and purified components of complement. Following fractionation of serum from 13 donors, anti-EBNA antibodies were always found to be associated with IgG, but were also detectable in the IgM fraction of four sera. Sequential addition of functionally pure complement components in the ACIF reaction showed that the classical sequence of complement activation in involved. Anti-EBNA antibody reactions in Raji cell nuclei can also be detected by anti-Ig immunofluorescence with a low level of sensitivity. The same pattern of granular fluorescence was observed when C3 (beta1A/beta1C), or C4 or IgG anti-EBNA antibodies were revealed with the corresponding flurescein-conjugated reagents. Blocking of the ACIF reaction was achieved with Fab 2 anti-EBNA antibody fragments, which therefore provided an appropriate specificity control for the detection of EBNA.

Adult↗
PubMed1975

Infants with congenital heart disease. Food intake, body weight, and energy metabolism.

Growth failure in infants with congenital heart disease was investigated by studies of food intake, change in body weight, oxygen consumption, carbon dioxide production, and lean body mass. Infants with congenital heart disease weighed less initially and gained less weight during observation than normal infants. The daily intake of calories per kilogram body weight was inadequate for some infants and considered generally adequate for others. Lean body mass was normal, and the quantity of oxygen used for metabolism was similar in both groups. Infants with congenital heart disease were not found to be hypermetabolic when oxygen consumption was related to lean body mass. The growth failure seen in these infants appears to be most appropriately related to inadequate calorie intake rather than to any other factor studied.

Body Composition↗
PubMed1975

Protein metabolism during intensive physical training in the young adult.

Two groups of men consumed two levels of protein (1.4 and 2.8 g/kg body weight) during a 40-day experimental period. Physical activity and the sweat rates were fairly high during the entire experimental phase. Urinary nitrogen excretions remained fairly constant for both groups during the training and heavy physical activity periods. Nitrogen balances were positive exclusive or inclusive of the daily sweat nitrogen losses showing nitrogen retention. The essentially unchanged blood hemoglobin and serum protein levels showed that the control group was receiving an adequate protein intake to maintain nitrogen equilibrium, under conditions of fairly heavy physical acitvity. Although others may have suggested some compensatory reductions in the urinary excretion of nitrogen under conditions of profuse sweating, our data have not supported these conclusions. It appears that sweat losses of nutrients become relevant in determining requirements and will increase in importance as sweat rates are increased. The data again demonstrate that the nutrient losses during profuse sweating consitute an error that could seriously invalidate the accuracy of metabolic balance studies. In this study, although the men did increase body protein stores and muscle mass with high-protein diets, the additional body protein did not enhance physiological work performance. It is suggested that in this sutdy 100 g of protein/day was adequate for men performing fairly heavy work.

Adult↗
PubMed1975

Combination chemotherapy with CCNU (NSC-79037),hexamethylmelamine (NSC-13875) and methotrexate (NSC-740) in advanced bronchogenic carcinoma.

18 patients with metastatic or recurrent bronchogenic carcinoma and one patient with a squamous cell carcinoma of the trachea were treated with a combination of CCNU, hexamethylmelamine and methotrexate. Objective remissions were observed in 3/19 (16%): 1 complete, 1 partial (greater than 50%) and 1 incomplete (less than 50%). However, the patient with the complete response was the only drug death, on day 21. Remission duration in the other two patients was 3 and 9+ months respectively. One patient with oat cell carcinoma experienced no tumor progression for 5 months. This combination resulted in severe gastrointestinal toxicity in 5/19, severe thrombopenia in 12/19 and severe neutropenia in 6/19. We conclude that the combination as used here resulted in no increased clinical effectiveness and proved to be quite toxic.

Aged↗
PubMed1975

Pulmonary melioidosis. Observations in thirty-nine cases.

During the 6-year period from 1965 through 1970, 39 patients with pulmonary melioidosis were treated at Fitzsimons Army Medical Center. Although this is a disease with a well-defined endemic area that does not include the United States, cases will no doubt continue to be seen in this country. These cases may result from acute infection in the endemic area, with subsequent travel to this country, or from delayed reactivation of a latent infection acquired months or years earlier. Given the potential for occurrence of this disease in the United States, continued awareness by the medical profession is important. The typical patient with subacute or chronic pulmonary melioidosis presents with fever, productive cough, weight loss, and a history of visiting an endemic area sometime in the past. Chest radiographs disclose upper lobe infiltrates and/or cavitation, suggesting granulomatous disease. With careful bacteriologic examination, sputum cultures are positive for Pseudomonas pseudomallei, which is susceptible to tetracycline, chloramphenicol, sulfonamides, and kanamycin. The titer of the indirect hemagglutinating antibodies will almost always be greater than 1:40. Most patients respond to therapy with tetracycline alone of in combination with chloramphenicol. Occasionally, a patient may require surgical intervention; if so, ideally the sputum should be negative, and a lobectomy, rather than segmentectomy, should be performed.

Adult↗