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Biomedical subjects

B Crawford

Publications and source records attributed to B Crawford.

At least 37 records · Page 2Linked to original sources
PubMed1997

Clinical economics and sleep disorders.

Sleep disorders have been shown to have substantial psychosocial sequelae with large economic impact. Numerous studies have examined the psychosocial aspects of sleep disorders; however, there has been little published on the associated economic implications. With increasing pressure to contain health care expenditures and provide value for the dollar, clinical economics is playing an important role in the decision-making process about alternative strategies within health care organizations. There are several strategies one may pursue to examine the economics of medical interventions. The predominant strategies include: cost identification, cost effectiveness, cost utility, and cost benefit. This review provides a basis for performing clinical economic evaluations in sleep disorders.

Costs and Cost Analysis↗
PubMed1994

Relationship between maternal and neonatal levels of antibodies to 48 kDa SSB(La), 52 kDa SSA(Ro), and 60 kDa SSA(Ro) in pregnancies complicated by congenital heart block.

OBJECTIVE: Since there is suggestive but, to date, indirect evidence that maternal anti-SSA(Ro) and SSB(La) antibodies are pathogenic in congenital heart block (CHB), we explored the hypothesis that binding to fetal tissues would result in selective depletion of autoantibodies from the neonatal circulation. METHODS: Maternal and umbilical cord levels of anti-48 kDa SSB(La), anti-52 kDa SSA(Ro) and anti-60 kDa SSA(Ro) antibodies were measured by ELISA and immunoprecipitation at parturition in 15 pregnancies complicated by CHB. A control group consisted of 13 pregnancies in which the mother was known to have antibodies to either SSA(Ro) and/or SSB(La) and the children did not have CHB. RESULTS: The ratios of maternal to cord serum levels of anti-48 SSB(La), anti-52 SSA(Ro) and anti-60 kDa SSA(Ro) antibodies ranged from 0.71 to 2.38 in both affected and unaffected pregnancies. The mean ratio obtained for each of the 3 autoantibodies was not significantly different between the 2 groups. Moreover these ratios did not significantly differ from the mean ratios obtained for total IgG levels in either group. CONCLUSION: These data demonstrate that maternal antibodies to all components of the SSA(Ro) SSB(La) system are efficiently transported across the placenta and are not selectively depleted in the circulation of neonates with CHB.

Antibodies, Antinuclear↗
PubMed1993

A systematic approach to spinal reconstruction after anterior decompression for neoplastic disease of the thoracic and lumbar spine.

The anterior approach to the thoracic and lumbar spine for neoplastic disease is now a well-accepted procedure, with results, for the most part, superior to those achieved with laminectomy. However, the specific indications for anterior decompression and the selection of reconstruction techniques based on the location and extent of bony destruction have received surprisingly little attention. The authors report their experience with the operative management of 33 patients with benign and malignant tumors of the thoracic and lumbar spine, using the anterior transthoracic or retroperitoneal approach. The role of stabilization and the relative indications for anterior or posterior instrumentation are emphasized. The mean age of patients was 58 years. Twenty-three patients were male. Five patients had benign tumors, and the remainder had a variety of metastatic lesions. Twenty-nine patients had lower extremity motor deficits, although 25 were ambulatory preoperatively. Thirty-seven noncontiguous resections were performed in 33 patients. In 13 patients, the resected vertebral body was replaced with acrylic or bone without instrumentation; in 18, the acrylic was supplemented with anterior instrumentation; and in 6, both anterior and posterior instrumentation were used. Above T11, vertebral reconstruction techniques were used to restore stability after decompression. Between T11 and L4, anterior instrumentation was used to supplement vertebral reconstruction in all patients. Supplemental posterior instrumentation was used for three-column involvement. Motor function was stabilized or improved in 94% of patients, and 88% of patients were ambulatory postoperatively. Of 28 patients with malignant disease, 23 died after a mean survival of 10.2 months (range, 2-51 mo) and 5 are alive a mean of 34.4 months since their operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Anatomic contribution to differences in rabbit colonic muscle contraction.

The aim of this study was to determine if differences in the force of contraction in different regions of the rabbit colon are associated with variations in the histology of the corresponding muscle tissues. Circular and longitudinal muscles were isolated from strips of proximal and distal colonic muscle. Muscle strips stretched to L0 were either stimulated to contract or were processed for electron microscopy. Cross-sections of the smooth muscle cells of the taenia coli had a larger perimeter (P less than 0.001) and were surrounded by increased extracellular matrix (28% of the standardized box) compared with the muscle cells from the other sites in the colon (7%-13%) (P less than 0.001). Cross-sections of the proximal circular muscle cells had a smaller perimeter and were present in a greater number than the cells from other areas of the colon. The distal circular muscle generated a larger force than the other muscles after stimulation with bethanechol or K+ (P less than 0.05). The taenia developed less force than the other muscles (P less than 0.05). Bethanechol was a less potent stimulant for the longitudinal muscles than for the circular muscles (P less than 0.05). This study suggests that (1) the decreased efficacy of bethanechol and K+ stimulation of the taenia coli is caused in part by the smaller number of cells that are available to contract and (2) the increased efficacy for the stimulation of the distal circular muscle compared with the proximal circular muscle is unrelated to the mass of muscle and seems to be related to an inherent property of the muscle.

Animals↗
PubMed1987

Psychological adaptation to pregnancy in childless women more than 35 years of age.

Forty-five pregnant childless women with a mean age of 36.6 years (+/- 1.7) were compared with 42 nulliparous pregnant women with a mean age of 26.7 years (+/- 2.8). Initial interviews determined the basic demographic data, the reasons for delaying pregnancy, attitudes to pregnancy, and plans concerning careers. Psychological tests were given to measure anxiety, depression, anger, marital intimacy, sense of autonomy, and role expectations. These psychological tests were applied to all patients at 12 to 16 weeks' gestation and again at 28 to 32 weeks' gestation. The demographic information from the two groups was remarkably similar. Although their ages differed by 10 years, their career goals, their family incomes, reasons for delaying pregnancy, and reasons for now getting pregnant revealed minimal differences. The Maffer Feminine Identity Scale revealed that the younger women held more traditional attitudes toward a woman's roles than the older group. The Sociotrophy-Autonomy Scale indicated that the older women were more independent than the younger pregnant patients. The Symptom Checklist indicated that the older group were less troubled by pregnancy than the control group, and although their level of distress increased as the pregnancy progressed, they remained better adjusted as they entered the last trimester of their pregnancies.

Adult↗
PubMed1986

Refractive changes induced by intraocular lens tilt and longitudinal displacement.

There is a tendency for the posterior chamber intraocular lens to tilt about the points of insertion. This is found clinically and in postmortem studies of eyes that have had intraocular lenses surgically implanted. One end is often located in the lens capsule and the other end is located in the ciliary sulcus. The possibility of anteroposterior displacement also exists. Using a modified Gullstrand schematic model eye, we have computed the amount of spherical and cylindrical errors that are induced due to the tilt and/or displacement of the intraocular lens. If a cylindrical error of approximately 90 degrees from the axis of insertion (lens plus haptic loops) and/or axis of tilt is detected, further careful investigation is warranted.

Astigmatism↗
PubMed1983

Treatment of caroticocavernous fistulae with detachable balloons introduced by percutaneous catheterization.

Five patients with caroticocavernous fistula were treated by new, interventional angiographic techniques. In four patients, latex balloons filled with a silicone polymer were introduced into the cavernous sinus via the transfemoral route and detached; this resulted in complete obliteration of the caroticocavernous fistula and preservation of the internal carotid artery flow in two of the four patients. In the fifth patient, stainless steel coils were introduced into the cavernous sinus via the superior ophthalmic vein which had previously been surgically exposed. These percutaneous, angiographic techniques of intervention should be considered the initial treatment of choice for caroticocavernous fistulae.

Adolescent↗
PubMed1983

Management of carotid-cavernous fistulas by surgery combined with interventional radiology. Report of two cases.

Two cases of carotid-cavernous fistulas were successfully treated by standard interventional radiology techniques after otherwise inaccessible vessels were surgically exposed. In the first case, an internal carotid artery (ICA), which had previously been ligated as part of an attempted surgical "entrapment" procedure, was recanalized to permit passage of a detachable balloon catheter to the fistula, resulting in its obliteration. In the second case, an enlarged superior ophthalmic vein was exposed and isolated to facilitate retrograde catheterization of the cavernous sinus and obliteration of a dural fistula between the ICA and the cavernous sinus by steel Gianturco coils. The methods and complications of both procedures are discussed.

Adolescent↗
PubMed1979

Cloned pigmented retinal epiehtlium. The role of microfilaments in the differentiation of cell shape.

3-wk-old clones of pigmented epithelial cells from chick retina can be divided into four zones on the basis of cellular morphology and pigmentation. These zones appear to represent different stages in the re-expression of differentiation: those cells with essentially no differentiated characteristics are at the outer edge and those with the greatest number are at the center. Cells of the colony exhibit three different types of movement when analyzed by time-lapse cinephotomicrography: focal contractions, extension and retraction of apical protrusions, and undulations of the lateral membranes. All the cells of the colony contain microfilaments, 4--7 nm in Diam, which are primarily arranged as apical and basal webs. In addition, less well defined filamentous networks are found in the apical protrusions and lateral interdigitations. When colonies are treated with 10 micrograms/ml of the drug cytochalasin B (CCB), the apical microfilament arrays are disrupted and movement stops. Both phenomena are reversible upon removal of the drug. During the process of redifferentiation, the cells change their shape from squamous to cuboidal, and the greatest change is found where the colony exhibits the greatest number of focal contractions. The evidence suggests that the apical microfilament arrays are directly responsible for the observed movements, particularly the focal contractions, and that focal contractions contribute to the development of the differentiated cellular shape. Possible roles for the other movements are discussed.

Animals↗