Biomedical subjects

D Y Rowland

Publications and source records attributed to D Y Rowland.

7 recordsLinked to original sources

PubMed1995

Use of fibrinolytic agents to coat wire implants to decrease infection. An animal model.

RATIONALE AND OBJECTIVES: Infection is a serious complication of metallic prosthesis implantation and may necessitate removal of the prosthesis. This study uses an animal model to evaluate the effects of coating stainless steel wire implants with fibrinolytic agents to prevent infection after bacterial contamination. METHODS: Three types of steel wire implants were used: plain stainless steel, heparin-coated steel, and urokinase-heparin-coated steel. Wire implants were incubated in a known concentration of Staphylococcus epidermidis and placed into the subcutaneous tissues of three groups of anesthetized hamsters. The implants and surrounding tissues were excised after 1 week and submitted for quantitative cultures. RESULTS: Using 100 organisms as the upper allowable limit to categorize abscesses as noninfected, the following rates of noninfectivity were observed: group 1 (control), 0% noninfected; group 2 (heparin-coated wire), 40% noninfected; and group 3 (urokinase-heparin-coated wire), 50% noninfected. The noninfectivity rates of groups 2 and 3 were significantly higher than the rate of group 1 (P < 0.001). There was no significant difference between groups 2 and 3 (P = 0.19). CONCLUSIONS: Both the heparin-coated and urokinase-heparin-coated wire exhibited significantly decreased infection rates compared with uncoated wire; the heparin coating may inhibit bacterial adherence. The urokinase coating of the heparin-coated wire appears to further decrease the infection rate, but not to a statistically significant degree.

Abscess↗

PubMed1994

Long-term developmental outcomes of method of delivery.

OBJECTIVE: In the general framework of relating birthing events to later mental development, this study addresses the hypothesis that uneventful non-vertex delivery is associated with higher intelligence than uneventful vertex delivery. STUDY DESIGN: In the course of a developmental obstetrical survey, data was gathered prospectively on families having a non-vertex birth at Huron Road Hospital during the 1950s and early 1960s. The intelligence quotient (IQ) scores and school success ratings for the cohort of 658 children who had been delivered uneventfully by specific non-vertex methods of birth (viz. elective section, breech and internal podalic version) are compared with those of 1151 of their own siblings and peers delivered by cephalic presentation without complication. Intrafamily comparisons allow the control of genetic and socioeconomic factors. RESULTS: The one-sided 95% confidence intervals (using the t-statistic) for mean values do not overlap. They are: IQ > 112.1 (non-vertex) vs. < 110.1 (vertex) and school success scores > 2.64 (non-vertex) vs. < 2.54 (vertex). These findings are confirmed for IQ when the analysis is restricted to only those 434 children in the families allowing intrafamily comparisons (i.e. comparable siblings born by both non-vertex and vertex deliveries). The one-sided 95% confidence intervals for mean values do not overlap. They are: IQ > 112.89 (non-vertex) vs. < 112.86 (vertex). CONCLUSIONS: Speculation is given as to the reasons for this phenomenon. It is unclear whether these differences are due to physical phenomena related to delivery or to effects due to differing levels of anesthesia-analgesia or whether these differences in intellectual potential are associated with the cause of obstetrical difficulties.

Delivery, Obstetric↗

PubMed1992

Effect of needle gauge, level of anticoagulation, and target organ on bleeding associated with aspiration biopsy. Work in progress.

Percutaneous fine-needle aspiration biopsy has gained wide acceptance due to its accuracy, ease of performance, and safety. This study was performed to evaluate the effect of needle size, coagulation impairment, or biopsy of different organs on risk of bleeding during the procedure. Multiple biopsy procedures were performed on the livers and kidneys of anesthetized pigs with 14-22-gauge Chiba-type needles. The procedures were performed under direct vision at laparotomy, and blood loss was measured. While larger needles generally produced more bleeding, the differences were statistically significant only when comparing 14- with 16-gauge needles and 16-gauge needles with the group of 18-, 20-, and 22-gauge needles in the liver. In the kidney, no significant difference was noted between 18-, 20-, and 22-gauge needles. Anticoagulation did not produce significantly greater blood loss but did allow separation of the group of 18- and 20-gauge needles from 22-gauge needles in the kidney. Renal biopsy resulted in greater overall blood loss than did liver biopsy.

Animals↗

PubMed1991

Retrospective study of fetal effects of prolonged labor before cesarean delivery.

Rising cesarean rates call for review of the indications for this procedure. Suspicion that subtle operatives, not reflected in morbidity and mortality rates, might be present inspired the study presented here. Three hundred fifty-two cesarean operations were done at Huron Road Hospital in the years 1952-1954. Examination of family records identified 97 probands delivered by cesarean after prolonged active labor before or during that period. Research efforts yielded 54 cases that were free of complications and had full historic data for both proband and sibling(s) of the same parentage, totaling 122 children. The intelligence quotient (IQ) scores of these families compared with that of the proband undergoing successive hours of labor suggested a detrimental effect of increasing length of trial labor. Statistical analyses of the 30 families in which the probands' trial labors exceeded 12 hours support that notion, as the probands had significantly lower IQ scores than their siblings born by elective cesarean with no labor (P = .006 to P less than .001). Probands had the lowest IQ scores in their families significantly more often (P less than .025) than could be expected to occur randomly. A similar pattern of school success occurred within the families.

Cesarean Section↗

PubMed1986

Prognostic factors in vitrectomy for epiretinal membranes of the macula.

A retrospective multivariate analysis of 264 consecutive cases of vitrectomy for removal of epiretinal membranes of the macula was performed. Two main preoperative prognostic factors were identified that were associated with the visual outcome of surgery: (1) the preoperative visual acuity, and (2) the duration of blurred vision before surgery. Discriminant functions constructed using these two factors allowed correct classification of eyes into an outcome group with good visual acuity with a 69% accuracy, and an 80% accuracy in classifying eyes into a group showing significant improvement in the level of visual acuity. Eyes that began with vision better than 20/100 tended to have slightly better postoperative visions than eyes with poorer preoperative visual acuity. However, eyes with worse preoperative vision tended to improve the greatest amount after surgery. Eyes with a longer history of blurred vision had poorer visual acuity after surgery and also less improvement in vision. Other statistically significant prognostic factors were identified; however, they did not appreciably improve the accuracy of the discriminant function in predicting visual outcome.

Adolescent↗

PubMedDate not supplied

Bleeding due to needle biopsy: effect of venopirin in an animal model and implications for humans.

PURPOSE: This study was undertaken to address the effect of platelet dysfunction on bleeding associated with percutaneous needle biopsy. MATERIALS AND METHODS: With use of an established animal model, 199 biopsies were performed on the livers of 13 anesthetized pigs (95 on control animals, 104 on venopirin-treated animals). The needles used were 16-22-gauge Chiba type, 18-gauge Tru-Cut, and 18-gauge Menghini. The biopsies were performed under direct vision at laparotomy with consistent technique. Blood loss was measured, and the results were compared. Statistical analysis was performed with the Student t test and the Turkey test, after logarithmic transformation of the data. RESULTS: A substantial increase in blood loss resulting from the biopsy procedures was demonstrated in the animals with platelet dysfunction. This was much greater than the effect of either needle size or prothrombin time prolongation previously reported by the authors. CONCLUSION: Platelet function may be an important factor in determining the risk of bleeding due to percutaneous needle biopsy.

Animals↗

PubMedDate not supplied

Young Investigator Award. In vivo treatment of infected prosthetic graft material with urokinase: an animal model.

PURPOSE: Pyogenic infection of vascular grafts represents a serious complication that may necessitate graft removal. If better treatment methods could be developed, perhaps some infected grafts could be salvaged and not removed. This study reports an animal model that evaluates the sterilization of contaminated vascular graft material implants with urokinase and antibiotics. MATERIALS AND METHODS: Polytetrafluoroethylene (PTFE) implants were incubated overnight in a known concentration of bacteria (Staphylococcus epidermidis) and were then implanted subcutaneously into four groups of anesthetized hamsters. The first group (control) received no treatment. The second group received urokinase injections twice daily into each abscess. The third group received intraabscess urokinase and systemic gentamicin twice daily. The fourth group received only systemic gentamicin. The hamsters were killed after 1 week. The graft implants and surrounding tissues were excised and submitted for quantitative cultures. RESULTS: With use of a cutoff value of 100 organisms per milliliter, below which the abscesses were considered noninfected, the following rates of noninfectivity were observed: group 1 (control), 5% noninfected; group 2 (urokinase only), 19.4%; group 3 (urokinase and gentamicin), 63.2%; and group 4 (gentamicin only), 32.5%. The noninfectivity rate of group 3 was significantly higher than that of all other groups combined (P < .001) and was significantly better than that of group 4 alone (P = .013). CONCLUSION: The combination of intraabscess urokinase and systemic gentamicin is very synergistic in graft sterilization. Urokinase may assist in the degradation of both fibrin and the biofilm produced by S epidermidis, thus improving penetration of antibiotics and local host defense mechanisms.

Abscess↗