Search PubMed⌕ Search

Biomedical subjects

J H Nelson

Publications and source records attributed to J H Nelson.

At least 55 records · Page 3Linked to original sources
PubMed1984

The prognostic significance of adenomyosis in endometrial carcinoma.

Depth of myometrial invasion is accepted as one of the most important prognostic factors in carcinoma of the endometrium. In an effort to define the significance of adenomyosis containing adenocarcinoma as it relates to myometrial invasion, 52 cases of Stage I adenocarcinoma with coexisting adenomyosis were identified. A subset of 11 cases was noted to have adenocarcinoma in adenomyosis, invasive to a depth greater than would have been appreciated had this entity not been identified. These 11 cases had a 100% 5-year survival, suggesting that adenocarcinoma in adenomyosis does not indicate a more ominous prognosis. The depth of invasion into the myometrium proper is the significant prognostic factor. The pathologist must be able to differentiate these two distinct entities to accurately assess prognosis.

Adenocarcinoma↗
PubMed1984

Presidential panel. The gynecologic oncologist in academic departments.

Now that the subspecialty of gynecologic oncology is well established within the specialty of obstetrics and gynecology, it seems timely to evaluate the pros and cons, the strengths and weaknesses of such a program as it interrelates with other programs in an academic department. A survey is presented which reflects the beliefs of both members and candidate members of the Society of Gynecologic Oncologists on such issues as gynecologic oncologists as chairmen of departments; teaching demands; time commitments to patient care and research in an academic institution; and surgical privileges for gastro-intestinal and urologic procedures in various hospitals. Financial and budgetary items are also discussed. Perspectives from three different points of view are presented as a discussion of the report of the survey.

Academic Medical Centers↗
PubMed1984

Sarcomas of the uterine corpus: prognostic factors and treatment.

Twenty-eight patients with sarcomas of the uterine corpus were followed at least 22 months or until death. All underwent laparotomy, eleven had radiation therapy, and six had chemotherapy. Three year actuarial survival was 24%, and three year actuarial local control was 36%. Multivariate analysis demonstrated that, as with sarcomas at other sites, the most important factors influencing survival were grade (P = 0.020) and stage (P = 0.022). For local control, multivariate analysis indicated the most important factors to be stage (P = 0.001) and radiation TDF (P = 0.01). Of 21 failures, 16 involved the pelvis, seven involved the upper abdomen, and 11 involved distant sites. The importance of both local and distant disease control is emphasized.

Adult↗
PubMed1984

A practical statistical quality control scheme for the industrial hygiene chemistry laboratory.

A computerized statistical quality control system has been developed for use in the industrial hygiene chemistry laboratory. The system is practical and sufficiently flexible to allow for multiple analytes, concentrations, replicate sizes and sample types. The computerized system provides an immediate evaluation of the quality of analytical results and produces automatically simple but informative accuracy and precision quality control charts.

Chemistry Techniques, Analytical↗
PubMed1984

Application of gas adsorption kinetics. I. A theoretical model for respirator cartridge service life.

Using the principles of gas adsorption kinetics, we have developed a new theoretical model addressing the adsorption and breakthrough of contaminant vapors or gases with respect to solid sorbents. Specifically, we have applied the theory to predict respirator cartridge service life in connection with individual contaminant exposure to toluene, vinyl chloride, ethyl acetate, and each of several different trichlorinated hydrocarbons at several levels of concentration. Theoretical expressions and contaminant breakthrough curves derived from our new approach are compared with those published previously by Mecklenburg and by Wheeler. The breakthrough curves derived by Mecklenburg and by Wheeler have approximately the same shape as the corresponding experimental curves for 0% to 40% breakthrough. However, these curves deviate in varying degrees from the experimental data at breakthrough values exceeding 40%. By contrast, our new theory agrees with published experimental results over the entire range of 0% to 100% breakthrough. The new model not only agrees with experimental observation, it is also less complicated and easier to apply to practical industrial hygiene problems than theories developed previously.

Adsorption↗
PubMed1984

Application of gas adsorption kinetics--II. A theoretical model for respirator cartridge service life and its practical applications.

A previously introduced theoretical model addressing respirator cartridge contaminant breakthrough was further developed in this study. This development involved the introduction of a new theoretical parameter, a, to complement the parameters k' and tau employed in the initial theoretical approach. The extension of the theory permits the theoretical investigation of the following: (1) the effect of contaminant concentration on breakthrough time; (2) the effect of flow rate on breakthrough time; (3) the influence of contaminant concentration on percentage of breakthrough; and (4) the effect of contaminant concentration on the weight of adsorbed contaminant at a given time. We also compared new theoretical expressions with previously published empirical equations. Utilizing the parameter a, we derived a set of equations of significant practical value. These equations relate the ratio of two contaminant concentrations (one experimental reference concentration and any other concentration of interest) to either the ratio of the corresponding breakthrough times or the corresponding weights of adsorbed contaminant. Three practical examples are provided demonstrating that the new theoretical model reduces experimental work required to predict respirator cartridge service life.

Adsorption↗
PubMed1984

Treatment of urinary incontinence after radical hysterectomy.

The results of therapy of eight previously untreated women without urinary fistulas who had been severely incontinent for three to eight years after radical hysterectomy are presented and the principles of management discussed. Radiologic and urodynamic studies are required to assess the bladder pressure response to filling, proximal urethral pressures, bladder neck closure at rest, and mobility of the bladder neck, to determine the mechanism responsible for the urine loss and to select appropriate therapy. Augmentation of proximal urethral pressures by medical or surgical means is required if the bladder neck is open at rest. All such patients improved dramatically on ephedrine, but tachyphylaxis developed in cases of total sphincter failure. Retropubic urethropexy did not relieve the incontinence in these cases, whereas a sling operation restored complete continence. If an incremental bladder pressure response to filling is present, operations to increase bladder outlet resistance are contraindicated. Treatment with anticholinergic medications was unsuccessful in these cases.

Adenocarcinoma↗
PubMed1983

The frequency, causes and prevention of severe urinary dysfunction after radical hysterectomy.

Urinary dysfunction that developed in 58 patients treated by radical hysterectomy, with or without total vaginectomy and whole pelvic irradiation over a 10-year period, was studied retrospectively by case record review and telephone enquiry. Seven of the 58 (12%) were found to be severely handicapped, six by incontinence and enuresis, and one by the complete inability to void. Twenty-one (36%) patients had absent bladder sensation or urine loss that caused only minor inconvenience. Advancing age, the menopause, whole pelvic irradiation, and total vaginectomy did not increase the likelihood of developing long-term urinary problems. The determining factor was whether the most lateral portions of the cardinal and uterosacral ligaments had been resected or spared at the time of surgery. It is concluded that serious disability may be avoided by conserving the lateral portions of the pelvic ligaments while obtaining adequate surgical margins during radical hysterectomy.

Female↗
PubMed1982

A 13C NMR study of methyl-branched hydrocarbon biosynthesis in the housefly.

Carbon 13 NMR, radiotracer and mass spectrometry studies were performed to confirm that propionate and methylmalonate are incorporated into long chain branched hydrocarbons as the methyl branch unit, to determine whether the branching methyl group was added initially or toward the end of the elongation process, to determine the precursor of methylmalonate, and to examine the metabolism of propionate in the housefly, Musca domestica. The labeled carbons from [3-13C]propionate and [methyl-13C]methylmalonate were incorporated into the branching methyl carbon of the methylalkanes, and into the even numbered carbons in alkanes and alkenes. The labeled carbons from [2-13C]propionate and [1-13C]propionate labeled the tertiary carbon and the carbon adjacent to the teritary carbon, respectively, in the methylalkanes. Mass spectral analysis of the methylalkanes after enrichment from [1-13C]propionate showed that propionate was incorporated during the initial stages of chain synthesis of the terminally branched alkanes. Sodium [2-13C]propionate labeled the odd numbered carbons of both the alkanes and alkenes. These data suggest that propionate is converted to an acetyl derivative, with carbon 3 of propionate converted to the carboxyl carbon of acetate, and carbon 2 of propionate converted to the methyl carbon of acetate. This pathway of propionate metabolism has hitherto only been reported in plants. The labeled carbons from DL-[3,4,5-13C3]valine were incorporated intact (as determined by 13C--13C coupling) into the branching methyl carbon, tertiary carbon, and carbon adjacent to the tertiary carbon, respectively, demonstrating that valine serves as a precursor to the methylmalonate used in branched alkane biosynthesis.

Alkanes↗
PubMed1981

Pretreatment staging.

The current rules of staging are reviewed briefly in this paper, and the various diagnostic procedures of value outlined. The use of the pretreatment laparotomy is discussed as it applies to cervical, endometrial, and ovarian malignancies. It has been shown to be of significant benefit in endometrial carcinoma under selected situations, whereas in cervical carcinoma there is new information indicating benefit to patients as well. It has enhanced our knowledge of the natural history of the diseases. The important details of its use are discussed along with current data showing the importance of the diaphragm, paraaortic nodes, and peritoneal cytology in defining the extent of disease.

Female↗
PubMed1981

A 13C-NMR study of the biosynthesis of 3-methylpentacosane in the American cockroach.

13C-NMR spectrometry was used to examine the in vivo incorporation of 13C-labeled precursors into 3-methylpentacosane in the cockroach Periplaneta americana. Natural abundance 13C-NMR of 3-methylpentacosane showed that carbons 1 through 6, 23 through 25 and the branching methyl carbon (C26) each gave distinct signals, with carbons 7 through 22 indistinguishable from each other. The label from dipotassium 2-[methyl-13C]methylmalonate was incorporated primarily into the methyl branch of 3-methylpentacosane, demonstrating the 2-methylmalonate is the precursor to the methyl branch unit. The carboxyl carbon from sodium [1-13C]propionate was incorporated exclusively into the 4-position. This indicates that propionate, as a 2-methylmalonyl derivative, is incorporated as the second unit during chain synthesis rather than toward the end of the elongation process. The labeled carbon from sodium [1-13C]acetate was incorporated into carbons 2, 6 and 24 and the labeled carbon from [2-13C]acetate was incorporated into carbons 1, 5, 23 and 25 of 3-methylpentacosane, respectively. These data are consistent with an elongation-decarboxylation pathway for 3-methylpentacosane biosynthesis.

Acetates↗