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Biomedical subjects

C W Brown

Publications and source records attributed to C W Brown.

At least 37 records · Page 2Linked to original sources
PubMed1998

Involvement of the sonic hedgehog, patched 1 and bmp2 genes in patterning of the zebrafish dermal fin rays.

The signaling molecule encoded by Sonic hedgehog (shh) participates in the patterning of several embryonic structures including limbs. During early fin development in zebrafish, a subset of cells in the posterior margin of pectoral fin buds express shh. We have shown that regulation of shh in pectoral fin buds is consistent with a role in mediating the activity of a structure analogous to the zone of polarizing activity (ZPA) (Akimenko and Ekker (1995) Dev. Biol. 170, 243-247). During growth of the bony rays of both paired and unpaired fins, and during fin regeneration, there does not seem to be a region equivalent to the ZPA and one would predict that shh would play a different role, if any, during these processes specific to fish fins. We have examined the expression of shh in the developing fins of 4-week old larvae and in regenerating fins of adults. A subset of cells in the basal layer of the epidermis in close proximity to the newly formed dermal bone structures of the fin rays, the lepidotrichia, express shh, and ptc1 which is thought to encode the receptor of the SHH signal. The expression domain of ptc1 is broader than that of shh and adjacent blastemal cells releasing the dermal bone matrix also express ptc1. Further observations indicate that the bmp2 gene, in addition to being expressed in the same cells of the basal layer of the epidermis as shh, is also expressed in a subset of the ptc1-expressing cells of the blastema. Amputations of caudal fins immediately after the first branching point of the lepidotrichia, and global administration of all-trans-retinoic acid, two procedures known to cause fusion of adjacent rays, result in a transient decrease in the expression of shh, ptc1 and bmp2. The effects of retinoic acid on shh expression occur within minutes after the onset of treatment suggesting direct regulation of shh by retinoic acid. These observations suggest a role for shh, ptc1 and bmp2 in patterning of the dermoskeleton of developing and regenerating teleost fins.

Animals↗
PubMed1996

Hypomagnesemia in postoperative spine fusion patients.

STUDY DESIGN: This was a retrospective review of 49 consecutive patient charts and a prospective study of 44 consecutive patients who underwent spinal fusion. OBJECTIVE: To determine the incidence and clinical significance of hypomagnesemia after spinal fusion. SUMMARY OF BACKGROUND DATA: Hypomagnesemia may be seen in 61% of patients in postoperative intensive care and may be associated with increased mortality. However, symptomatic hypomagnesemia is rare. METHODS: A retrospective review of the charts of 49 consecutive patients who underwent spine fusion was completed to determine postoperative magnesium levels. Twenty-seven patients with postoperative hypomagnesemia received routine magnesium replacement regardless of symptoms. Forty-four patients who underwent spine fusion were studied prospectively for postoperative hypomagnesemia. Prospectively studied observational patients who developed hypomagnesemia were treated only when clinical signs or symptoms of magnesium deficiency occurred. RESULTS: Postoperative hypomagnesemia occurred in 28 of 49 retrospectively studied patients who underwent spine fusion (57%) and 38 of 44 prospectively studied patients who underwent spine fusion (86%). Symptoms associated with hypomagnesemia developed in three of 44 prospectively studied and two of 49 retrospectively studied patients who underwent spine fusion (7% and 4%, respectively). The combined incidence for symptomatic hypomagnesemia was five of 93 patients. (5.4%). The majority of patients from the prospective study with postoperative hypomagnesemia were asymptomatic, and their magnesium levels returned to normal within 4 days, with or without treatment. CONCLUSIONS: This study confirmed a high incidence of hypomagnesemia in patients who underwent spine fusion, although only 5.4% developed clinical signs or symptoms of magnesium deficiency. The cause of hypomagnesemia remains speculative.

Adolescent↗
PubMed1996

Functional outcome of thoracolumbar burst fractures managed with hyperextension casting or bracing and early mobilization.

STUDY DESIGN: A retrospective study to review the results of unstable thoracolumbar burst fractures managed with casting or bracing and early ambulation in neurologically healthy patients. OBJECTIVES: To determine the clinical outcome of patients with unstable burst fractures of the thoracolumbar spine treated without surgery, and to identify any variables that may adversely influence the final outcome. SUMMARY OF BACKGROUND DATA: The management of unstable fractures of the thoracolumbar spine as described by Bedbrook involves a period of recumbency for 6-8 weeks followed by gradual mobilization. Newer techniques of surgical stabilization of the fracture and decompression of the neural elements have become popular because immediate stability of the spine is created and because the need for prolonged bedrest and hospitalization is eliminated. There have been only three reports in the literature describing the nonoperative management of these fractures with early mobilization; some authors believe that this is appropriate only if the posterior column is intact. The results reported in the literature of nonoperative management of thoracolumbar burst fractures have indicated that this is an effective method of management. METHODS: A retrospective review of 26 patients with unstable burst fractures in the thoracolumbar region (T11-L2) was performed; follow-up evaluation was obtained from 24 patients. Clinical follow-up examination was performed by the use of a questionnaire in which the patients were asked to rate their pain, ability to work, ability to perform in recreational activities, and their overall satisfaction with treatment. RESULTS: Mean follow-up time for the 24 patients was 34.3 months. Mean duration of hospitalization was 8.2 days; those patients who did not have injuries other than their spine fracture had a mean hospitalization time of 5.9 days. Kyphotic deformity could be corrected with hyperextension casting but tended to recur during the course of mobilization and healing. No correlation was found between kyphosis and clinical outcome. At final follow-up evaluation, 19 patients (79%) had little or no pain; 18 patients (75%) had returned to work; 18 (75%) stated that they had little or no restrictions in their ability to work, and 16 (67%) stated that they had little or no restrictions in their ability to participate in recreational activities. Only one patient (4%) reported being dissatisfied with the initial nonoperative treatment of his spine fracture. Ten patients were found to have evidence of spinous process widening on plain films; there was no significant difference in the clinical or radiographic outcome of these 10 patients when compared with the 14 others who did not have interspinous widening. CONCLUSIONS: Nonoperative management of thoracolumbar burst fractures with hyperextension casting or bracing was proven to be a safe and effective method of treatment in selected patients. Clinical results were favorable; no neurologic deterioration was observed; hospitalization times were minimized, and patient satisfaction was high. The authors do not believe that ligamentous injury of the posterior column is a contraindication to nonoperative management of thoracolumbar burst fractures.

Adolescent↗
PubMed1996

Multifocal metachronous epidural abscesses of the spine. A case report.

STUDY DESIGN: A retrospective case report of a patient who had a lumbar epidural abscess treated surgically who then developed a cervical epidural abscess that also required surgical treatment. OBJECTIVES: To describe a patient in whom treatment of a single epidural abscess with surgery and antibiotics was not sufficient to eradicate the systemic infection. SUMMARY OF BACKGROUND DATA: Epidural abscesses are most commonly seen after invasive procedures that violate the epidural space. Epidural abscesses are usually a solitary event occurring in only one location and are usually treatable with surgical drainage and parenteral antibiotics. METHODS: An elderly patient presented with neck and shoulder pain and fever. Evaluation revealed degenerative disease of the cervical spine. Within a week, she developed a cauda equina syndrome secondary to a lumber epidural abscess. The abscess was drained and intravenous antibiotics were given. Seventeen days later, while still receiving antibiotics, she developed a cervical epidural abscess which also required surgical drainage. RESULTS: The patient showed gradual improvement in her neurologic status. No recurrence of either epidural abscess was observed. CONCLUSIONS: An epidural abscess may represent a serious systemic infection that requires aggressive treatment. Close follow-up is necessary to ensure that the infection has been eradicated and that no recurrent abscess has formed in the same or a different location. Aggressive antibiotic treatment is also strongly recommended.

Abscess↗
PubMed1995

Thiazide diuretics induce cutaneous lupus-like adverse reaction.

One of the side effects reported in patients taking thiazide diuretics is photosensitivity. We report two patients who developed lupus-like skin lesions while taking thiazide diuretics. One patient developed erythematous scaling papules, patches and plaques on the upper extremities and trunk resembling subacute cutaneous lupus erythematosus. Histopathology of a skin biopsy from the trunk showed basal cell layer liquefaction and lichenoid interface changes suggestive of lupus erythematosus. The skin lesions resolved completely within two months of discontinuing thiazide therapy. The second patient developed multiple flesh colored urticarial plaques on the trunk one year after beginning thiazide therapy. Slight lichenoid interface changes were noted on a skin biopsy, along with dense mucin deposition in the papillary and deep dermis, suggestive of tumid lupus erythematosus. The skin lesions persisted despite discontinuing thiazide therapy, necessitating systemic corticosteroid treatment. Both patients had circulating anti-SSA/Ro autoantibodies and antinuclear antibodies. These two patients illustrate that thiazide diuretics may induce a cutaneous lupus erythematosus-like adverse reaction and production of anti-SSA/Ro autoantibodies as demonstrated by immunodiffusion, immunoblot and immunoprecipitation testing.

Aged↗
PubMed1994

Stabilization of thoracic spine fractures resulting in complete paraplegia. A long-term retrospective analysis.

STUDY DESIGN: The impact of surgical stabilization on initial rehabilitation and complications in patients with traumatic thoracic level paraplegia was investigated. One hundred thirteen patient records were retrospectively reviewed. SUMMARY OF BACKGROUND DATA: Forty-six patients had been treated with surgical stabilization and fusion. Nineteen patients had been treated by laminectomy alone. Forty-eight patients had been treated nonoperatively. The most common mechanism of injury was a motor vehicle accident (52.6%). The mean follow-up was 8.4 years. METHODS: All inpatient and outpatient records at Craig Hospital were reviewed for patients who had sustained a thoracic spine fracture (T2-T9) that resulted in complete paraplegia (Frankel A). All patients were followed for a minimum of 5 years. Data were collected regarding initial length of inpatient rehabilitation, as well as early and late complications that affected rehabilitation and function during follow-up. This information was analyzed by treatment group. RESULTS: There was a statistically significant difference in the length of initial rehabilitation days between the surgically stabilized group and the laminectomy-only group. There was a trend toward fewer in-patient rehabilitation days between the surgically stabilized group and the nonoperatively treated group. The surgically treated group had twice as many complications as the nonoperative group. CONCLUSIONS: The surgical stabilization of thoracic (T2-T9) spine fractures with complete paraplegia tends to decrease initial rehabilitation days but is associated with increased overall complications. The treatment of this patient group clearly must be individualized.

Adult↗
PubMed1994

Gastroesophageal reflux complicating choanal atresia repair.

Four infants with bilateral congenital choanal atresia (CCA) underwent transpalatal (3) or transnasal (1) repairs. Postoperatively all four infants experienced gastroesophageal reflux (GER) with intermittent nasal reflux. GER was documented by GER radionuclide scanning in one patient and by dual nasopharyngeal and esophageal pH probe studies in the remaining three patients. The infants with documented GER required prolonged stenting and dilations for choanal restenosis and granulations. The literature emphasizes the importance of the technical repair for prevention of these complications; GER can be a significant complicating factor.

Choanal Atresia↗
PubMed1994

A drug dissolution monitor employing multiple fiber optic probes and a UV/visible diode array spectrophotometer.

A traditional dissolution pumping system was recently replaced with a fiber optic interface between the spectrometer and the samples. However, the system was limited to a single sample vessel. In this study, a dissolution testing system with six vessels connected to a diode array spectrometer via six optical fibers was investigated. A bifurcated fiber optic bundle was used to transfer the light from the source to the dissolution vessels and was networked so that spectra of each sample can be measured periodically. A full spectrum calibration method based on Principal Component Regression (PCR) was used to determine the concentrations of active ingredients and to account for interferences due to excipients in tablet formulations. Results on this new fiber optic interface system are compared with those obtained previously with the traditional pumping system. Standard errors of prediction are between 1.5 and 3.2% using cross-validation and between 1.1 and 1.7% for the direct validation of two active ingredients in two different drug formulations.

Calibration↗
PubMed1994

Soft-tissue injuries of the cervical spine.

Cervical sprain syndrome is usually the result of a hyperextension injury of the neck; symptoms include neck, intrascapular and arm pain, and headache. Associated complaints of the head, neck, and upper extremities are common. The mechanism and pathophysiology of this injury, and the occurrence of associated injuries are discussed. Patient evaluation, treatment, and prognosis are reviewed. A thorough understanding of this common injury should facilitate treatment and provide the patient and physician with realistic expectations for recovery.

Accidents, Traffic↗
PubMed1993

Automated drug dissolution monitor that uses a UV-visible diode array spectrophotometer.

A method for performing multicomponent analysis in drug dissolution testing without chromatographic separation is presented. Aliquots from dissolution vessels are automatically transferred to a UV-visible diode array spectrophotometer, spectra are measured, and the aliquots are returned to the testing vessels. A full-spectrum calibration method based on principal-component regression is used to simultaneously determine the concentrations of active ingredients and to account for interferences due to excipients in a tablet formulation. The system was evaluated with two commercial pharmaceutical formularies; the first contained pseudoephedrine hydrochloride and chlorpheniramine maleate, whereas the second was a mixture of phenylpropanolamine hydrochloride and chlorpheniramine maleate. The selections of standard mixtures for calibration and validation were based on a factorial design.

Calibration↗
PubMed1993

The diagnostic and therapeutic role of endoscopic retrograde cholangiopancreatography in children.

We performed 121 endoscopic retrograde cholangiopancreatographies (ERCPs) in 92 patients (60 girls and 32 boys), aged 4 months to 19 years, as part of diagnostic evaluation for suspected pancreatic or biliary tract disease or as therapeutic intervention. ERCP was successful in 116 attempts. The most common indications were recurrent pancreatitis (35 children), nonresolving acute pancreatitis (20), unexplained elevated amylase or lipase (19), postcholecystectomy syndrome (14), and elevated biliary tract enzymes (12). One hundred and one ERCPs were performed for more than one indication. The most common findings included chronic pancreatitis (26 cases), pancreas divisum (14), dilated pancreatic duct (10), gallstones or sludge (8), and abnormal common bile duct (8). Complications were uncommon and usually minor. ERCP is a safe and helpful procedure in the evaluation of suspected pancreatic and biliary tract disease in children and frequently allows for nonoperative treatment of these disorders.

Abdominal Pain↗
PubMed1993

Acquired spinal stenosis secondary to an expanding thoracic vertebral hemangioma.

Intraosseous hemangioma is a slow-growing primary benign neoplasm of capillary, cavernous, or venous origin. The most common type is the cavernous hemangioma, composed of large thin-walled vessels and sinuses lined by endothelial cells. Although found in any bone, hemangioma is most common in the vertebrae, where it represents 2-3% of all radiographically detectable spinal tumors. Most spinal hemangiomas are solitary, asymptomatic lesions of the vertebral body, with 10-15% showing concomitant involvement of the posterior elements. Rarely, the lesion is located to the posterior arch. An unusual case of an expanding vertebral hemangioma isolated to the posterior elements of T9 is presented.

Adult↗
PubMed1992

Heparin management protocol for cardiopulmonary bypass influences postoperative heparin rebound but not bleeding.

A group of 63 adult patients undergoing cardiac surgical procedures requiring cardiopulmonary bypass (CPB) were studied to examine the relationship between heparin doses administered and postoperative bleeding. Patients were randomly assigned either to receive heparin 200 U/kg and additional heparin as needed to reach and maintain an activated clotting time (ACT) greater than 400 s for CPB (group A, n = 30), or to receive heparin 400 U/kg and additional heparin as needed to reach and maintain a whole blood heparin concentration greater than 4.0 U/ml for CPB (group H, n = 33). Groups were compared for the amount of postoperative bleeding, heparin rebound, homologous transfusion requirements, and standard laboratory coagulation tests. In the last 33 patients studied, additional tests of platelet aggregation and plasma levels of beta thromboglobulin (BTG), antithrombin III, and several markers of fibrinolysis were measured and compared by group. The mean heparin dose was 28,000 +/- 4,800 U for group A and 57,000 +/- 10,700 U for group H (P less than 0.05 for group A vs. group H). At 8 and 24 h postoperatively, mediastinal drainage did not differ significantly between groups (mean 24-h drainage +/- SD = 901 +/- 414 ml in group A, 1035 +/- 501 ml in group H), nor did the incidence of transfusion with homologous blood products.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Open reduction and internal fixation of an acetabular fracture during pregnancy.

Fractures of the pelvis and acetabulum are common injuries in a mechanized society and frequently occur in the younger age groups. Commonly associated injuries such as hemorrhage, urethral tears, gastrointestinal injuries, and major vessel damage are well reported and well known to orthopaedic surgeons. Another less frequently reported complication of pelvic fractures is the potential association with pregnancy and subsequent childbirth. This problem was first described by Malgaigne in 1857 in his classic article on double vertical fractures of the pelvis, in which he described a 34-year-old woman with a pelvic fracture who subsequently died during childbirth. A review of the literature reveals numerous articles addressing potential problems with parturition subsequent to a pelvic fracture and several articles dealing with pelvic fractures occurring during pregnancy. The current literature on pelvic fractures during pregnancy, however, recommends only nonoperative treatment and, to our knowledge, there have been no reports of operative fixation during pregnancy. The purpose of this article is to report a case of an acetabular fracture in a pregnant woman treated with open reduction and internal fixation, who went on to carry a full-term baby and have a normal delivery.

Accidents, Traffic↗
PubMed1992

The natural history of thoracic disc herniation.

Fifty-five patients with 72 thoracic disc herniations were retrospectively reviewed in an effort to ascertain the natural history of this disease. The treatment programs given to these patients were evaluated, and 15 (27%) of the 55 patients eventually required surgery. The majority, however, did not require surgery and have continued to perform activities of daily living, some even participating in vigorous sports activities (eg, skiing) without any apparent neurologic consequences. Thoracic disc herniations, similar to cervical and lumbar disc herniations, do not always lead to major neurologic compromise. A less aggressive surgical approach therefore can be considered.

Adult↗