Biomedical subjects
Publications and source records attributed to R L Jones.
Brucella abortus biotypes 1 and 2 were recovered from various tissues of a naturally infected cow. This result indicates a need for biotyping multiple isolates of B. abortus from several affected animals in a herd before the biotype of the infecting strain can be definitively established.
An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (133Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected 133Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Several hematologic abnormalities have been defined in patients with diabetes mellitus, despite the lack of classic hematologic pathologic findings in this condition. Studies of the erythrocyte and the formation of hemoglobin A1c have provided a means of documenting glycemia and a model reaction for diabetic sequelae through postsynthetic protein modification. Oxygen affinity has been noted to be abnormal in the diabetic erythrocyte, concomitant with a decreased concentration of inorganic phosphorus, glycosylation of the 2,3-diphosphoglycerate binding site or preexisting vascular disease. Red cell membrane viscosity has also been documented to be increased in the hyperglycemic subject. Abnormalities in the polymorphonuclear leukocyte have been described, involving the properties of adherence, random migration, chemotaxis, phagocytosis and killing. Certain metabolic abnormalities are also present in this cell type. The lymphocyte has been shown to have abnormal metabolic properties, mitogen responses and cell surface properties in diabetes both in animals and human subjects. Certain subpopulations of lymphocytes appear to be especially vulnerable to changes concomitant with diabetes mellitus. In vitro abnormalities of platelet behavior have been widely studied, although the in vivo significance of these findings remains controversial. Studies of the fluid phase of coagulation have suggested the existence of a hypercoagulable state in hyperglycemic subjects. The clinical significance of most of these findings remains to be defined. Nevertheless, the observation that many of the abnormalities described are reversible when hyperglycemia is corrected has given impetus to the development of improved systems of glucose "control" for diabetic patients.
Explore the source record for details and available documents.
Host-range mutants of adenovirus 5 that contain a defect in region E1A (0-4.5 units) fail to replicate in HeLa cells and to transform rodent cells. In HeLa cells, these mutants synthesize only the two RNAs from E1A that share the same 5' and 3' termini but differ in length by the amount of internal sequence removed by splicing. RNA from wild-type virus, selected by hybridization to DNA from region E1A, translates into polypeptides of Mr 51,000 and 48,000 that are highly acidic in isoelectric focusing gels. These acidic Mr 51,000 and Mr 48,000 polypeptides are encoded by the longer and shorter E1A RNAs, respectively. Two of the host-range mutants, H5hr1 and H5hr2, fail to synthesize the Mr 51,000 polypeptide but do produce the Mr 48,000 polypeptide and a novel polypeptide thought to be a truncated portion of the Mr 51,000 polypeptide. H5hr1 and H5hr2 are hypothesized to have termination codons in sequences found only in RNA encoding the Mr 51,000 polypeptide. This prediction is verified for H5hr1 by DNA sequence analysis. The other three host-range mutants (H5hr3-5) synthesize both acidic polypeptides and are predicted to be missense. These results strongly imply that the Mr 51,000 polypeptide, alone or in combination with the Mr 48,000 polypeptide, is needed to regulate expression of adjacent viral genes during the early phase of adenovirus infection.
The capacity of excised internode sections of pea to grow and secrete protons in response to indoleacetic acid (IAA) and Ca(2+) and K(+) treatments was examined. By incubating unpeeled and unabraded sections in rapidly flowing solutions, it was shown that acidification of the external medium in the presence or absence of IAA is dependent on the presence of Ca(2+) and K(+). Similar results were obtained when unpeeled and unabraded sections were incubated in dishes with shaking. When peeled or abraded sections were incubated with shaking in IAA, H(+) release was also dependent on the presence of Ca(2+) and K(+). The release of H(+) from sections incubated in Ca(2+) and K(+) is not caused by displacement of H(+) from binding sites in the cell wall. Rather, the release of protons from sections is temperature dependent, and it is concluded that this is a metabolically linked process. Although Ca(2+) and K(+) are essential for the release of H(+) from isolated stem sections of peas, these cations do not influence elongation. Despite the large increase in proton release induced by Ca(2+) and K(+) either in the presence or absence of auxin, growth in the presence of these ions was never greater than it was in their absence. Furthermore, cations do not affect the neutral sugar or uronic acid composition of the solution which can be centrifuged from isolated sections. As is the case for growth, an increase in the neutral sugar and uronide composition of the cell wall solution is dependent only on IAA. It is concluded that IAA-induced growth of pea stem sections is independent of the secretion of protons.
The metabolism of polysaccharides by pea stem segments treated with and without auxin was investigated using a centrifugation technique for removing solution from the free space of the cell wall. Glucose is the predominant sugar in both the ethanol-soluble and ethanol-insoluble fractions of the cell wall solution extracted with water. In the water-soluble, ethanol-insoluble polysaccharides, arabinose, xylose, galactose, and glucose make up 9.5, 23.8, 23.9, and 39.9%, respectively, of the neutral sugars, while rhamnose, fucose, and mannose are present at concentrations between 0.5 and 2.0%.Auxin treatment enhances the levels of xylose and glucose in ethanol-insoluble polysaccharides relative to controls, and this difference can be detected within 30 minutes of auxin treatment. Cellulose-binding experiments show that the enhanced levels of xylose and glucose are in a polymer having the cellulose-binding properties of xyloglucan. (3)H-glucose labeling experiments confirm the auxin-enhanced metabolism of the xyloglucan fraction; however, increased labeling of arabinose is also observed in auxin-treated sections. Auxin treatment also causes a marked increase in the level of uronic acids centrifuged from pea internode sections. Thus, after 3 hours of incubation in indoleacetic acid, the level of uronic acids in the ethanol-insoluble polysaccharides which can be recovered by centrifugation is increased 2- to 3-fold over sections incubated in water. These auxin-enhanced changes in xylose, glucose, and uronic acids are correlated with enhanced rates of section growth.Incubation of excised pea internode sections in acidic buffers also enhances the rate of xyloglucan and polyuronide metabolism. This acid-enhanced metabolism of xyloglucan and polyuronide is inhibited by low temperature, suggesting that it is enzyme-mediated.Extraction of the cell wall solution with CaCl(2) increases the yield of all neutral sugars. Arabinose and mannose are increased 4- and 3-fold, respectively, and xylose and glucose by about 20%, while galactose levels are 40% higher in cell wall solution extracted with CaCl(2) than in that extracted with water. Although calcium increases the amount of neutral sugars extracted, it does not affect the auxin-induced changes in neutral sugars. Extraction of the cell wall solution with ethyleneglycol-bis-(beta-aminoethyl ether)-N,N'tetraacetic acid enhances the yield of uronic acids and also increases the difference due to auxin treatment.
The effect of ethylene on cell wall metabolism in sections excised from etiolated pea stems was studied. Ethylene causes an inhibition of elongation and a pronounced radial expansion of pea internodes as shown by an increase in the fresh weight of excised, 1-cm sections. Cell wall metabolism was studied using centrifugation to remove the cell wall solution from sections. The principal neutral sugars in the cell wall solution extracted with H(2)O are arabinose, xylose, galactose, and glucose. Both xylose and glucose decline relative to controls in air within 1 hour of exposure to ethylene. Arabinose and galactose levels are not altered by ethylene until 8 hours of treatment, whereupon they decline in controls in air relative to ethylene treatment. When alcohol-insoluble polymers are fractionated into neutral and acidic polysaccharides, xylose and glucose predominate in the neutral fraction and arabinose and galactose in the acidic fraction. Ethylene depresses the levels of xylose and glucose in the neutral fraction and elevates arabinose and galactose in the acidic fraction. Ethylene treatment does not affect the level of uronic acids extracted with H(2)O; however, the level of hydroxyproline-rich proteins in this water-extracted cell wall solution is increased by ethylene. Extraction of sections with CaCl(2) results in an increase in the levels of neutral sugars particularly arabinose. Ethylene depresses the yield of arabinose in calcium-extracted solution relative to controls in air. Similarly, extraction with CaCl(2) increases the yield of extracted hydroxyproline in ethanol-insoluble polymers and ethylene depresses its level relative to controls. Metabolism of uronic acids and neutral sugars and growth in response to ethylene treatment contrast markedly with auxin-induced polysaccharide metabolism and growth. With auxin, sections increase mostly in length not radius, and this growth form is associated with an increase in the levels of xylose, glucose, and uronic acids. With ethylene, on the other hand, stem elongation is suppressed and expansion is promoted, and this growth pattern is associated with a decrease in xylose and glucose in the ethanol-insoluble polysaccharides.
Prostaglandin E2 (PGE2) and prostaglandins I2 (PGI2) were infused into the renal artery of either sodium-loaded or sodium-depleted dogs. Systemic blood pressure was decreased and arterial plasma renin concentration increased in the sodium-loaded dogs by infusion of PGI2 (1200 ng/min). Both compounds increased renal blood flow but PGE2 had a much more potent effect than PGI2 on increasing urine flow and sodium excretion. In the sodium-depleted dogs systemic blood pressure was significantly decreased and arterial plasma renin concentration increased by infusions of PGI2 (300 and 1200 ng/min) and PGE2 (300 ng/min). Both compounds stimulated urine flow and renal blood flow but PGE2 induced a much larger increase in sodium excretion than PGI2. PGI2 exerts its actions on renal function by inducing vasodilatation whereas PGE2 also has a direct action on tubular function.
A 33 year old male Nigerian presented with widespread involvement of peripheral nerves, several of which were tender and painful. Nerve biopsies confirmed the presence of Mycobacterium leprae in both endoneurial and perineurial areas, mainly in foamy macrophages (Virchow cells), but there were also large accumulations of an amorphous, acid-fast and alcohol-fast material which was not obviously of bacterial origin. Appropriate stains indicated that this had many characteristics of lipofuscin. Although not previously known, it was at this stage discovered that the patient had received treatment with anti-leprosy drugs nearly three years before presentation in this country. One of these was clofazimine, an aniline aposafranine derivative known to produce a ceroid-like pigment in the tissues of patients treated with this drug or lepromatous leprosy.
Tests of overall lung function often reveal abnormalities in elderly smokers, but lung function is less consistently deranged in young smokers. Since airway closure at higher than normal lung volumes is thought to be an early indicator of lung dysfunction in asymptomatic smokers, we used 133xenon to measure regional residual volume, which is affected by airway patency, with the expectation that any abnormalities present in young smokers may be more apparent if searched for on a regional basis. We found no significant difference in overall lung function between 11 nonsmokers and 20 smokers (mean age=23.8 years), but residual volume was significantly higher in the lower-lung regions of the smokers. The results indicate that even in young persons the lungs are functionally disturbed by smoking, and the pattern of abnormality is similar to that seen in patients with chronic obstructive lung disease.
The early and accelerated atherosclerosis associated with diabetes mellitus is probably multifactorial in origin. Hyperglycemia, in addition to its numerous pathologic effects on lipids, hormonal profiles, the vascular tree, and platelets, is also associated with effects on the fluid phase of coagulation. The most striking abnormality of coagulation described in diabetes mellitus is a decrement in fibrinogen survival that is rapidly reversible with correction of hyperglycemia or the administration of heparin but not with aspirin and dipyridamole administration, suggesting a hypercoagulable state. Abnormalities of clotting factor assays and circulating levels have been reported in patients with diabetes mellitus, but most of these studies are complicated by the controversy over the results being due to diabetes mellitus or due to the presence of vascular lesions concomitant with diabetes. Nevertheless, an increasing amount of evidence implicates the participation of the fluid phase of coagulation in both the initiation and propagation of diabetic vascular complications.
Platelet survival by 51chromium labeling was determined in six normal control subjects and in twelve patients with diabetes mellitus, before and after improved glucose control (mean HbA1c 10.5 +/- 2.2% and 7.1 +/- 1.8%, respectively). Mean platelet survival was 9.47 +/- 0.85 days for the normal subjects and 9.04 +/- 1.40 and 9.90 +/- 1.05 for the diabetic subjects in hyperglycemic and improved glycemic states, respectively. The differences between these values were not statistically significant. However, platelet survivals performed in three diabetic patients who had severe retinal disease requiring photocoagulation were significantly shortened compared with nonsmoking control subjects (P less than 0.05) or to patients without severe retinopathy (P less than 0.01). These observations imply that measurable changes in in vivo platelet survival occur after the development of small vessel disease. It remains to be determined whether abnormalities described for diabetic platelets in vitro or changes in in vivo platelet physiology contribute to the initiation or propagation of vascular disease in the hyperglycemic individual.
The Quality Assurance Program of Walter Reed Army Medical Center is described. This program has been in effect since January 1, 1978 and is ongoing. The logical derivation of the use of the repeat film analysis as the focus of the Quality Assurance Program is described in detail. This repeat analysis procedure includes (1) the collection of all repeat and discarded film; (2) the separation of all repeat and discarded film into types according to the etiology leading to their being discarded; and (3) evaluation of radiographic artifacts to analyzed the types of artifacts, the mistakes which lead to these artifacts, and the means of eliminating the causes of these artifacts. Artifacts are categorized according to patient error, physician error, radiographer error, machine error, film screen processor error, etc. Statistics of this analysis are presented from January 1, 1978 through July 1, 1979. Pertinent examples of different types of errors are illustrated and the logical step-by-step process leading to the elimination of causes is explained in detail.