Biomedical subjects

W Ladd

Publications and source records attributed to W Ladd.

8 recordsLinked to original sources

PubMed1999

Multiple vs. single betamethasone therapy. Neonatal and maternal effects.

OBJECTIVE: To identify potential neonatal benefits and possible neonatal and maternal complications associated with repeated use of antenatal corticosteroids. STUDY DESIGN: A retrospective chart review was done on all gravidas < 34 weeks who were hospitalized and received antenatal betamethasone at our institution between January 1, 1992 and April 30, 1996. Regression analysis was performed to investigate the relationship between single vs. multiple course of betamethasone and multiple variables. RESULTS: After controlling for significant covariates, multiple courses of betamethasone were associated with a decrease in oxygen use (P < .01). A nonsignificant decline in respiratory distress syndrome and assisted ventilation was noted. No effect on birth weight or maternal or neonatal infection was seen. CONCLUSION: Repeated use of betamethasone is associated with a significant decrease in oxygen use in the preterm neonate. No significant maternal or neonatal complications were found. A prospective, randomized trial is necessary.

Adult↗

PubMed1999

Enthacrynic and acid effects on inner wall pores in living monkeys.

PURPOSE: The influence of the inner wall of Schlemm's canal on aqueous outflow facility remains poorly understood. We examined the relationship between inner wall pore characteristics and outflow facility in living primate eyes in which facility had been pharmacologically increased by ethacrynic acid (ECA) infusion and in contralateral control eyes. METHODS: Outflow facility (two-level constant pressure perfusion) was measured in eight pairs of living monkey eyes before and after administration of a bolus dose of either 0.125 mM ECA or vehicle. After exsanguination, eyes were fixed in situ under constant-pressure conditions (mean fixation pressure approximately 19 mm Hg). The density and diameter of inner wall pores and the number and area of platelet aggregates on the inner wall of Schlemm's canal were measured by scanning electron microscopy. RESULTS: In ECA-treated eyes, outflow facility increased 63% (P < 0.0001), intracellular pore density decreased 46% (P = 0.0094), intracellular pore size increased 27% (P = 0.049), platelet aggregate density increased 158% (P < 0.0001), and area covered by platelets increased 210% (P = 0.012) relative to contralateral controls. Although the average density and size of intercellular pores were essentially unaffected by ECA, an increased density of large (> or = 1.90 microm) intercellular pores was seen in ECA-treated eyes. The density of intracellular pores increased with the duration of fixative perfusion. Other than a weak negative correlation between outflow facility and intracellular pore density in ECA-treated eyes (P = 0.052), facility was not correlated with inner wall pore features. CONCLUSIONS: Our data are most consistent with a scenario in which ECA promotes formation of large intercellular pores in the inner wall of Schlemm's canal, which are then masked by platelet aggregates. Masking of intercellular pores, combined with fixation-induced alteration of inner wall pore density, greatly complicates attempts to relate facility to inner wall structure and suggests that in vivo pore density is smaller than in fixed tissue. Additionally, facility-influencing effects of ECA on the juxtacanalicular tissue cannot be excluded.

Animals↗

PubMed1998

Molteno implant with mitomycin C: intermediate-term results.

PURPOSE: The authors examine the intermediate-term effects of adjunctive intraoperative mitomycin C (MMC) in a cohort of patients who received double-plate Molteno implants for complicated glaucomas. METHODS: A consecutive series of 21 patients who received MMC 0.5 mg/ml for 5 minutes as an adjunct to a double-plate Molteno implant was compared by life-table analysis to a historical control group of 18 patients who received either no adjunct or 5-fluorouracil (5-FU) but no MMC. RESULTS: At three years follow-up, 35% (95% confidence interval (CI), 15-57%) of patients who received MMC avoided failure criteria of intraocular pressure (IOP) less than 6 mm Hg or more than 21 mm Hg, addition of glaucoma medication, reoperation for glaucoma, or tube removal. Seventeen percent (95% CI, 4-37%) of patients in the control group at three years follow-up met similar criteria (p = 0.039). No late complications of tube erosion were seen in the MMC group. CONCLUSION: Intraoperative MMC offers an increased likelihood of a two- to three-year period of medication-free IOP control in patients undergoing double-plate Molteno implants, compared to similar patients receiving 5-FU or no adjunctive antimetabolite therapy.

Adult↗

PubMed1998

Trabeculectomy with mitomycin C: intermediate-term results.

PURPOSE: This study was performed to provide results 2 to 3 years after trabeculectomy with mitomycin C (MMC). METHODS: A consecutive series of all 68 patients who underwent trabeculectomy with MMC was analyzed using Kaplan-Meier life-table statistics and compared with other published retrospective analyses. RESULTS: At 2- and 3-year follow-up examinations, 59% (95% confidence interval [CI], 44-70%) and 47% (95% CI, 32-61%) of patients, respectively, avoided an intraocular pressure (IOP) of more than 21 mmHg or less than 20% below their preoperative level without glaucoma medication on two consecutive occasions more than 1 month apart after 3 months follow-up (75% [95% CI, 60-84%] and 70% [95% CI, 53-81%], respectively, with medication) and avoided additional glaucoma surgery. Loss of more than three lines of visual acuity on two occasions more than 1 month apart after 3 months follow-up occurred in 28% of patients (> 2 lines in 44%) at 3 years. Nonreversible causes of loss of three lines of acuity occurred in 13% of patients. Complications requiring reoperation occurred in 16% of patients and included hypotony maculopathy (4%) and late bleb leaks (4%). CONCLUSIONS: At the 3-year follow-up evaluation, trabeculectomy with MMC provided an approximately 50% chance of maintaining IOPs less than 21 mmHg and a more than 20% IOP reduction without concomitant use of glaucoma medication, which increased to 70% with the addition of medication. This procedure was associated with an approximately 30% risk of substantial visual loss (approximately 15% nonreversible) and a 15% chance of reoperation for complications.

Adult↗

PubMed1992

Metabolic cardiac imaging in severe coronary disease: assessment of viability with iodine-123-iodophenylpentadecanoic acid and multicrystal gamma camera, and correlation with biopsy.

Fifteen patients with coronary disease and resting left ventricular ejection fractions of less than or equal to 0.35 underwent resting metabolic cardiac imaging utilizing 1 mCi [123I]iodophenylpentadecanoic acid (IPPA) intravenously and a multicrystal gamma camera. Parametric images of regional rates of IPPA clearance and accumulation were generated. Forty-two vascular territories (22 infarcted) were evaluated by metabolic imaging as well as transmural myocardial biopsy. Despite resting akinesis or dyskinesis in 20/22 (91%) infarcted territories, 16/22 (73%) of these territories were metabolically viable. Transmural myocardial biopsies in all patients (43 sites, 42 vascular territories) during coronary bypass surgery confirmed IPPA results in 39/43 patients (91%). When compared to biopsy, scan sensitivity for viability was 33/36 (92%) with a specificity of 6/7 (86%). Eighty percent of bypassed, infarcted but IPPA viable segments demonstrated improved regional systolic wall motion postoperatively as assessed by exercise radionuclide angiography. We conclude resting IPPA imaging identifies viable myocardium, thereby providing a safe, cost-effective technique for myocardial viability assessment.

Biopsy↗

PubMed1990

Functional cardiac imaging in coronary disease: increased sensitivity of first-pass radionuclide angiography utilizing sequential regional left ventricular early diastolic filling rate images.

In 127 patients, 113 with greater than or equal to 50% coronary artery stenosis (CAD), 14 with normal coronaries, cardiac catheterization and first-pass radionuclide angiography (RNA) utilizing left ventricular (LV) regional ejection fraction, first half systolic LV regional mean transit time and ejection rate images were performed. Additionally, the incremental value of a new technique, sequential regional LV filling rate images focusing on the first third of diastole, was established. Diastolic imaging improved RNA sensitivity from 88% (100/113) to 96% (109/113). Single vessel disease sensitivity increased from 77% (23/30) to 90% (27/30), whereas multivessel disease RNA positivity changed from 93% (77/83) to 99% (82/83). LAD system (LAD/D) sensitivity improved by 24% to 94% (79/84); RCA system (RCA/PDA) sensitivity increased 17% to 84% (59/70); circumflex system (CFX/OM) sensitivity was 83% (67/81), an improvement of 5%. Specificity was well maintained despite the increased sensitivity, as 86% (12/14) of patients with normal coronaries were normal by RNA. Furthermore, in the 113 CAD patients, 81% (84/104) of the vessels with insignificant or no stenosis were normal by RNA. We conclude sequential regional LV diastolic filling images substantially increase RNA sensitivity for CAD, while specificity is satisfactorily maintained.

Coronary Disease↗

PubMed1986

Oblique planes of section in MR imaging.

Magnetic resonance (MR) imaging allows freedom in choosing oblique planes of section and rotation of the image plane with respect to the frequency-encoded (F) and phase-encoded (P) dimensions. A general method is described for understanding geometric relationships between the fixed magnetic coordinate system, patient positioning, and the flexible observer's coordinate system. Oblique planes of section are clinically useful in studying organs with an axis of symmetry that is oblique to the magnet coordinate system, such as the heart. Rotation of the image plane can be used to move motion artifacts away from anatomic regions of interest, such as the liver and spine. Appropriate use of oblique section selection and image rotation can improve MR image quality and diagnostic value of the patient study.

Humans↗

PubMed1976

Elemental analysis of biological specimens in air with a proton microprobe.

The unique capabilities of the proton microprobe in an atmospheric environment as a biological tool are illustrated in studies of arsenic and mercury distributions in siingle strands of hair from poisoning victims and of the distributions of several abundant elements in frozen hydrated eye and kidney specimens from rats.

Animals↗