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Biomedical subjects

N L Smith

Publications and source records attributed to N L Smith.

72 records · Page 4Linked to original sources
PubMed1981

An anatomic basis to prevent ischemia of the colon during operations upon the aorta.

According to standard practice, the inferior mesenteric artery, when sacrificed, should always be ligated at its origin, proximal to the left colic branch. However, it should not be sacrificed and ligated but instead, be reimplanted if any doubt exists regarding the adequacy of the collateral circulation. The patient is in a high risk category for development of ischemia of the colon if there is an occlusion or absence of the marginal artery at the splenic flexure; absence of the middle colic artery; occlusion of one or both hypogastric arteries, or enlargement of the left colic artery, suggesting occlusion of the superior mesenteric artery.

Aged↗
PubMed1978

Calcium transport by the normal rat colon in vivo and in vitro.

We studied calcium transport in vivo and in vitro in large bowel of normally fed young male rats. Solutions containing zero, 1.7, 3.4 and 5.0 mM calcium and isotopic 45Ca as tracer were perfused in vivo through the lumen of cecum and descending colon. In vitro flux studies were also carried out in cecum with 2.0 and 0.2 mM calcium solutions utilizing the technique of Ussing and Zerahn whereby both chemical and electrical gradients across planar sheets of cecal tissues were nulled. The combined findings demonstrated that (i) cecum was more permeable to calcium than descending colon indicating a proximal to distal absorption gradient in large bowel; (ii) the transport of calcium in both segments increased with increasing luminal calcium concentration, and (iii) calcium transport in both cecum and descending colon was passive only. Thus the large bowel appears to play only a minor role in calcium homeostasis in the normally fed rat.

Animals↗
PubMed1975

Quantitative analysis of triclocarban in blood.

A method is presented for quantitatively determining triclocarban in blood. Triclocarban is extracted from blood with ether, isolated by TLC, and measured through its UV absorption at 265 nm in methanol. This method is sensitive to 250 ng (50 ppb in 5 ml of blood) of free triclocarban with a relative standard deviation of 5.2%, correlated with a radiotracer analysis of 14C-labeled triclocarban. It has been applied successfully to the analysis of triclocarban in human and rabbit blood.

Animals↗
PubMed1975

Quantitative analysis of tribromsalan in blood and urine.

Tribromsalan can be quantitatively measured in whole blood and urine by a technique involving extraction with ethyl acetate, treatment with silica gel, separation by TLC, and quantitative measurement by fluorescent spectrophotometry. This method has a sensitivity down to 125 ng (25 ppb in 5.0 ml of sample) of free tribromsalan and shows an average 90% recovery of tribromsalan in blood and urine with standard deviations of 9.7 and 7.4%, respectively.

Animals↗
PubMedDate not supplied

Hemorrhoidal bleeding following transrectal prostatic biopsy. Etiology and management.

Three cases of rectal bleeding within a series of 120 transrectal prostatic biopsies are reported. The precipitating factor was the presence of hemorrhoids which were unsuspected prior to prostatic biopsy. Rectal bleeding in these patients was arrested by ballon tamponade with a 24 French Foley catheter. In situ monitoring of the rectal Foley catheter was discontinued when no further rectal bleeding was ascertained. There were no complications due to this simple, safe, and effective technique. When hemorrhoids are suspected, preliminary proctoscopy aids and alerts surgeons to choose alternative routes to the prostatic bed.

Aged↗
PubMedDate not supplied

Successful fibrinolytic therapy for superior vena cava thrombosis secondary to long-term total parenteral nutrition.

Thrombosis of the superior vena cava and other major central veins is an unusual and infrequent complication of total parenteral nutrition. When it does occur, it may be life threatening and prompt therapy is indicated. A case of superior vena cava thrombosis secondary to an indwelling Broviac catheter for long-term parenteral nutrition is presented, which was successfully treated with Streptokinase with reestablishment of flow through the catheter and veins.

Aged↗
PubMedDate not supplied

Lack of association between first myocardial infarction and past use of erythromycin, tetracycline, or doxycycline.

To evaluate the association of prior treatment with antibiotics active against Chlamydia pneumoniae with the risk for incident myocardial infarction, we conducted a population-based case-control study. We found that use of erythromycin, tetracycline, or doxycycline during the previous 5 years was not associated with risk for first myocardial infarction. These results suggest little or no association between the use of these antibiotics and the risk for first myocardial infarction in the primary prevention setting.

Adult↗
PubMedDate not supplied

Ferric sulfate pulpotomy in primary molars: a retrospective study.

PURPOSE: This investigation collected clinical and radiographic data from a retrospective chart review of patients receiving ferric sulfate pulpotomies with a sub-base of zinc oxide eugenol in a clinical practice over a five-year period. METHODS AND MATERIALS: Clinical and radiographic data were available for 242 primary molars in 171 children with follow-up times ranging from 4-57 mos (mean = 19 mos). RESULTS: The overall radiographic success rate ranged from 74-80%. The frequency of normal appearing pulps decreased over time. The most frequently observed pulpal responses were calcific metamorphosis (6-33%) and internal resorption (7-18%). Overall clinical success was 99%. Only 9 of the 242 teeth were extracted due to radiographic and/or clinical failure. A survival analysis demonstrated that the overall cumulative probability of survival remained high over time with a cumulative survival of over 90% after 3 years. CONCLUSIONS: The overall success rates in this study are lower than those reported previously in the literature for ferric sulfate pulpotomies, but are comparable with those reported for 1:5 dilution, 5-min formocresol pulpotomies.

Child↗
PubMedDate not supplied

The significance of cervical cytologic dysplasia.

The cytologic screening experience of the University of New Mexico Cytopathology Laboratory was reviewed for a nine-year period in order to evaluate the potential for progression of cervical squamous dysplasia to severe dysplasia and carcinoma. Entry conditions for dysplasia study were two initial negative smears in order to standardize the cytologic history to a reasonable extent. Relative likelihood of progression was calculated for three levels of cytologic dysplasia and was compared to those of negative and positive smears in order to ascertain the relative risk of the various levels of cytologic atypia. Slight, moderate an severe dysplasia were, respectively, 9.0, 26.3 and 83.3 times more likely than a negative smear to be followed by one positive for carcinoma or showing severe dysplasia. Histologic follow-up of study subjects was correlated with their cytologic history. Cytologic follow-up of patients with slight, moderate and severe dysplasia indicated a high spontaneous regression rate. Time for conversion from negative cytology to severe dysplasia or positive cytology for histologically confirmed cases averaged 3.0 years. An unexpected finding was a 12.5% false-negative rate for severe dysplasia and positive cytology, indicating a need for caution in advising repeat smears in lieu of a biopsy for confirmation of these findings.

Carcinoma in Situ↗
PubMedDate not supplied

The risk of myocardial infarction associated with antihypertensive drug therapies.

OBJECTIVE: To assess the association between first myocardial infarction and the use of antihypertensive agents. DESIGN AND SETTING: We conducted a population-based case-control study among enrollees of the Group Health Cooperative of Puget Sound (GHC). PATIENTS AND METHODS: Cases were hypertensive patients who sustained a first fatal or nonfatal myocardial infarction from 1986 through 1993 among women and from 1989 through 1993 among men. Controls were a stratified random sample of hypertensive GHC enrollees, frequency matched to the cases on age, sex, and calendar year. All 623 cases and 2032 controls had pharmacologically treated hypertension. Data collection included a review of the ambulatory medical record a brief telephone interview of consenting survivors. Antihypertensive therapy was assessed using the GHC's computerized pharmacy database. RESULTS: The first analysis included only the 335 cases and 1395 controls initially free of cardiovascular disease. Compared with users of diuretics alone, the adjusted risk ratio of myocardial infarction was increased by about 60% among users of calcium channel blockers with or without diuretic (risk ratio = 1.62%; 95% confidence interval [Cl], 1.11 to 2.34; P = .01). The second analysis was restricted to 384 cases and 1108 controls who were taking either a calcium channel blocker or a beta-blocker. Among these subjects, the use of calcium channel blockers compared with beta-blockers was associated with about a 60% increase in the adjusted risk of myocardial infarction (risk ratio = 1.57; 95% Cl, 1.21 to 2.04; P < .001). While high doses of beta-blockers were associated with a decreased risk of myocardial infarction (trend P = .04), high doses of calcium channel blockers were associated with an increased risk (trend P < .01). CONCLUSIONS: In this study of hypertensive patients, the use of short-acting calcium channel blockers, especially in high doses, was associated with an increased risk of myocardial infarction. Ongoing large-scale clinical trials will assess the effect of various antihypertensive therapies, including calcium channel blockers, on several important cardiovascular end points. Until these results are available, the findings of this study support the current guidelines from the Joint National Committee on the Detection, Evaluation and Treatment of High Blood Pressure that recommend diuretics and beta-blockers as first-line agents unless contraindicated, unacceptable, or not tolerated.

Adrenergic beta-Antagonists↗