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Biomedical subjects

N D Baker

Publications and source records attributed to N D Baker.

At least 19 recordsLinked to original sources
PubMed1999

Comparison of polytomography and computed tomography for fracture assessment.

OBJECTIVE: To compare polytomography (PT) and computed tomography (CT) for visualizing fractures and arthrodeses, with and without metal hardware, to determine whether CT could adequately replace PT. DESIGN AND PATIENTS: An ex vivo bovine model containing fractures in three planes, reduced with metal hardware, was created to compare fractures using PT and CT. The radiation dose at the skin surface was calculated for both examinations. For in vivo assessment, images of 14 patients who underwent both PT and CT (15 fractures, five arthrodeses) were coded, sorted, and independently read by four musculoskeletal radiologists. They rated the degree of certainty of their assessment. Time factors for patients and personnel and financial costs were also compared. RESULTS: In the ex vivo model the fractures were well seen on both PT and CT. The radiation dose was higher for PT than for CT. In vivo, the degree of certainty in assessment of fractures and arthrodeses was higher for PT than CT in studies in which metal hardware was present, but there was no significant difference in studies without metal hardware or in the combined (with and without hardware) studies. The patient's and technologist's time required to perform a PT examination was greater than that for CT. CONCLUSION: In the assessment of fractures and arthrodeses containing metal hardware, PT is recommended. For studies without hardware, CT is equivalent and can replace PT.

Animals↗
PubMed1998

Hip arthrography, aspiration, block, and bursography.

Hip arthrography in children with Legg-Calvé-Perthes disease is used to determine the optimal position of the femoral head for immobilization during the process of epiphyseal healing and in developmental dysplasia of the hip as a guide to operative treatment. In adult hips, arthrography and aspiration are useful techniques for demonstration of prosthetic implant loosening and infection. Aspiration of the hip joint and culture of aspirated fluid helps to diagnose septic arthritis. Anesthetic hip arthrography helps to distinguish between pain originating from the hip and radicular pain from the spine. Iliopsoas bursography may be used to diagnose bursal enlargement and its cause.

Adult↗
PubMed1998

Combined phacoemulsification and trabeculectomy versus trabeculectomy alone: a comparison study using mitomycin-C.

BACKGROUND AND OBJECTIVE: To compare the results of combined phacoemulsification and trabeculectomy (PEM/TRAB) plus mitomycin-C with those of trabeculectomy alone (TRAB) plus mitomycin-C. PATIENTS AND METHODS: The authors retrospectively reviewed 42 eyes in 38 consecutive patients who underwent combined PEM/TRAB with mitomycin-C. An age-matched control group of 42 patients who underwent TRAB with mitomycin-C during the same time period was randomly selected from 248 consecutive patients. All patients had a minimum of 12 months of follow-up. RESULTS: Mean preoperative intraocular pressure (IOP) and number of glaucoma medications were similar for the two groups (22.8 +/- 6.9 mm Hg vs 22.9 +/- 6.8 mm Hg, 2.12 +/- 0.8 vs 2.26 +/- 1.0 medications, combined PEM/TRAB vs TRAB, respectively). Postoperative IOP was significantly lower at all follow-up intervals. At final follow-up after a mean of 21.8 +/- 6.0 months, IOP averaged 13.9 +/- 5.1 mm Hg in the PEM/TRAB group and 12.3 +/- 4.7 mm Hg in the TRAB group. Bleb survival was excellent in both groups, although slightly higher in the TRAB group (37 of 42 PEM/TRAB vs 41 of 42 TRAB). Both groups required significantly fewer glaucoma medications at final follow-up (0.38 +/- 0.6 vs 0.5 +/- 0.8, PEM/TRAB vs TRAB). Complications were similar between the two groups. CONCLUSION: The success rate for combined PEM/TRAB appears to approach that of TRAB alone.

Aged↗
PubMed1996

Ewing's sarcoma of the sacrum.

A lytic lesion with soft-tissue extension in the sacrum of a 47-year-old man was needle-biopsied under computed tomographic (CT) guidance using an 18-gauge cutting needle. The cytologic appearance of the lesion and immunohistochemical staining were diagnostic of Ewing's sarcoma. Specifically, a new marker (O13) for the presence of glycoprotein p30/32 mic2 in Ewing's sarcoma was utilized.

12E7 Antigen↗
PubMed1996

Treatment of the fellow eye in acute angle-closure glaucoma: a case report and survey of members of the American Glaucoma Society.

PURPOSE: A survey of members of the American Glaucoma Society was compiled to determine the treatment practices of subspecialty-trained glaucoma specialists regarding the treatment of the fellow eye in acute angle-closure glaucoma. METHODS: We surveyed 200 members of the American Glaucoma Society regarding treatment options for the fellow eye of a patient with acute angle-closure glaucoma. The survey was mailed and was preceded by a case of a patient who had acute angle-closure glaucoma and in whom definitive prophylactic laser iridotomy was temporarily deferred; her eye developed acute angle-closure glaucoma despite treatment with pilocarpine. RESULTS: One hundred fifty-five of the 200 mailed surveys were answered and returned. Pilocarpine alone was the most common response category (50.3% of respondents), followed by observe/close follow-up (32.9%). Other response categories were selected by < 5% of the respondents. CONCLUSION: Pilocarpine is well supported by the literature and by subspecialty-trained glaucoma specialists as the treatment of the fellow eye in cases of acute angle-closure glaucoma when laser iridotomy is temporarily deferred. The present case reminds us that the fellow eye is highly susceptible to acute angle closure glaucoma and that prophylactic laser iridotomy should be performed at the earliest possible juncture.

Acute Disease↗
PubMed1993

Late argon laser suture lysis after mitomycin C trabeculectomy.

BACKGROUND: Argon laser suture lysis has been effectively used in the early post-operative period to enhance filtration after trabeculectomy. The most substantial reductions in intraocular pressure (IOP) occur when laser suture lysis is performed during the first 2 postoperative weeks, and virtually no effect has been reported after the fourth postoperative week. Mitomycin C, used as adjunct therapy, improves the success rate of trabeculectomy in high-risk eyes and may change the time course for effective suture lysis. METHODS: The authors used late laser suture lysis in five high-risk patients after mitomycin C trabeculectomy. The mean patient age was 66.8 +/- 15.7 years, and laser suture lysis was performed an average of 13 +/- 5.8 weeks (range, 7-21 weeks) after surgery. RESULTS: The mean IOP before suture lysis was 20.2 +/- 3.8 mmHg. The average IOP reduction immediately after suture lysis was 11.4 +/- 3.9 mmHg. The average IOP 3 to 4 months after laser suture lysis was 9.4 +/- 3.4 mmHg. CONCLUSION: The authors postulate that adjunctive mitomycin C therapy markedly delays wound healing and appears to extend the period that laser suture lysis is clinically effective.

Adult↗
PubMed1991

Uptake, cytotoxicity and metabolism of m-azidopyrimethamine and related lipophilic antifolates in SV-K14 human keratinocytes in vivo.

The growth-inhibitory properties of a series of lipophilic diaminopyrimidine antifolates were evaluated in comparison with methotrexate (MTX) against SV-K14 human keratinocytes in vitro under folate-dependent and folate-independent conditions. Under folate-dependent conditions metoprine (DDMP) proved more cytotoxic than MTX, despite the greater inhibitory activity of the latter compound against mammalian dihydrofolate reductase (DHFR), possibly reflecting differences in cellular accumulation. The significantly lower activity of both compounds under folate-independent conditions indicated DHFR as the primary target. Pyrimethamine (PYM), m-azidopyrimethamine (MZP) and m-aminopyrimethamine (MAP), a metabolite of MZP, were approximately equiactive but less cytotoxic than MTX or DDMP. The unexpected activity of MAP, an inferior DHFR inhibitor, suggests differences in the mechanism of action or cellular transport of the drug, although the reduction of cytotoxicity observed under folate-independent conditions indicate folate metabolism as the cytotoxic locus. In contrast, the cytotoxicity of PYM or MZP was not reduced under folate-independent conditions implying an alternative mechanism of action. The uptake of 2-[14C]pyrimethamine by SV-K14 keratinocytes was rapid with steady-state intracellular concentrations being observed after approximately 100 min, partition of drug into the plasma membrane preceding redistribution and extensive accumulation within the particulate cell components. The previously reported NADPH-dependent metabolism of MZP to MAP by murine liver microsome preparations was not observed with SV-K14 keratinocytes nor with murine skin homogenates in the present study.

Animals↗
PubMed1987

Central retinal vein occlusion and malignant glaucoma.

Malignant (ciliary block) glaucoma developed in three patients with primary open angle glaucoma with preexisting central retinal vein occlusion following trabeculectomy. Two of the three patients had 360 degrees open angles prior to surgical trabeculectomy. Although the relationship may be coincidental, we propose that central retinal vein occlusion may be a risk factor for the development of malignant glaucoma following filtering surgery.

Aged↗
PubMed1986

Symptomatic vertebral hemangiomas: a report of four cases.

Neural compression complicating vertebral hemangioma is associated with: compression fracture, hematoma, epidural extension of tumor, and/or bony expansion or "ballooning." Four cases of symptomatic vertebral hemangioma are presented. Discussion includes imaging modalities, preoperative embolization, and surgical approach.

Adult↗
PubMed1986

Cardiovascular effects of ophthalmic timolol.

We studied cardiovascular effects related to ophthalmic timolol maleate, a beta-adrenergic blocker commonly used to treat chronic glaucoma. Twenty normal subjects were randomly assigned to two double-blind treatment groups each with ten subjects. One group received two drops of ophthalmic timolol (0.5%) twice daily for 4 weeks, and the other received two drops of placebo (artificial tears) twice daily for 4 weeks. Ophthalmic timolol significantly decreased resting and maximal exercise heart rate after the first dose and maximal exercise heart rate during chronic dosing. Chronic timolol administration reduced oxygen consumption at maximal exercise and blunted the augmentation in exercise capacity seen during chronic placebo therapy. Cardiac sympathetic tone and inotropy were reduced after ophthalmic timolol treatment. Despite the presence of drug-induced cardiovascular effects, the plasma levels of timolol were often undetectable and never exceeded 2.8 ng/mL.

Adult↗
PubMed1983

Rheumatoid arthritis simulating other lesions.

Radiographs of patients with rheumatoid arthritis can sometimes be misleading. Seven of 69 patients with RA had radiographs sufficiently atypical to lead clinicians to suspect other disorders (e.g., gout, lupus erythematosis, thrombophlebitis). Five of these cases are presented and the diagnosis in each case is discussed.

Adult↗
PubMed1982

Liposarcoma complicating neurofibromatosis. Report of two cases.

Liposarcoma complicating neurofibromatosis is a rare entity. Until now, only two cases have been reported in the literature. The authors present two new cases of liposarcoma arising in generalized neurofibromatosis with detailed microscopic findings. Other neoplasms associated with neurofibromatosis are also discussed.

Adolescent↗
PubMed1978

Spontaneous osteonecrosis of the knee and medial meniscal tears.

Several factors may play a role in the etiology of "spontaneous" osteonecrosis of the medial femoral condyle. Corticosteroids are known to induce osteonecrosis, and 45% of the patients in this study received steroids parenterally or by intra-articular injection. Another factor, heretofore given little attention, is the association of medial meniscal tears and "spontaneous" osteonecrosis. Twenty-one (78%) of 27 knees examined by arthrography demonstrated meniscal tears. Stress concentration over the edge of the meniscal fragment may result in ischemic necrosis of the femoral condyle. Early detection of a medial meniscal tear by arthrography in older patients and prompt treatment may be important in avoiding the late changes of "spontaneous" osteonecrosis.

Adolescent↗