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Biomedical subjects

R J Cummings

Publications and source records attributed to R J Cummings.

At least 19 recordsLinked to original sources
PubMed2001

Role of Src kinase in diperoxovanadate-mediated activation of phospholipase D in endothelial cells.

We have shown earlier that oxidant-induced activation of phospholipase D (PLD) in vascular endothelial cells (ECs) is regulated by protein tyrosine kinases. To further understand the regulation of oxidant-induced PLD activation, we investigated the role of Src kinase. Treatment of bovine pulmonary artery ECs (BPAECs) with a model oxidant, diperoxovanadate (DPV), at 5 microM concentration, for 30 min, stimulated PLD activity (four- to eightfold), which was attenuated by tyrosine kinase inhibitors and by Src kinase-specific inhibitors PP-1 and PP-2, in a dose- and time-dependent fashion. Furthermore, BPAECs exposed to DPV (5 microM) for 2 min showed activation of Src kinase as observed by increased tyrosine phosphorylation and autophosphorylation in Src immunoprecipitates, which was attenuated by PP-2. Src immunoprecipitates of cell lysates from control BPAECs exhibited PLD activity in cell-free preparations, which was Arf- and Rho-sensitive and was enhanced at 2 min of DPV (5 microM) treatment. Also, Western blots of Src immunoprecipitates of control cells revealed the presence of PLD(1) and PLD(2), suggesting the association of PLD with Src kinase under basal conditions. However, exposure of cells to DPV (5 microM) for 2 min enhanced the association of PLD(2) but not PLD(1) with Src. Western blotting of immunoprecipitates of PLD(1) and PLD(2) isoforms of control BPAECs revealed the presence of Src under basal conditions and exposure of cells to DPV (5 microM) for 2 min enhanced the association of PLD(2) with Src in PLD(2) immunoprecipitates. Transient expression of a dominant negative mutant of Src in BPAECs attenuated DPV- but not TPA-induced PLD activation. In cell-free preparations, Src did not phosphorylate either PLD(1) or PLD(2) compared to protein kinase Calpha or p38 mitogen-activated protein kinase. These data show for the first time a direct association of Src with PLD in ECs and regulation of PLD in intact cells.

Animals↗
PubMed1998

Persistent Horner's syndrome after spinal fusion and epidural analgesia. A case report.

STUDY DESIGN: A case report of a clinical observation. OBJECTIVES: To present the clinical findings of an unusual complication of spinal fusion and epidural analgesia. SUMMARY OF BACKGROUND DATA: A 13-year-old girl developed Horner's syndrome after posterior thoracic spinal fusion and epidural analgesia. METHODS: By clinical examination and pupillary pharmacologic testing, the diagnosis of Horner's syndrome was confirmed. RESULTS: Examination and testing confirmed the presence of central or preganglionic Horner's syndrome. The specific cause of the Horner's syndrome was not determined. Horner's syndrome persisted, and the blepharoptosis was corrected surgically. CONCLUSIONS: This is the first reported case of Horner's syndrome occurring after posterior spinal fusion and epidural analgesia.

Anesthesia, Epidural↗
PubMed1998

Interobserver reliability and intraobserver reproducibility of the system of King et al. for the classification of adolescent idiopathic scoliosis.

The classification of adolescent idiopathic scoliosis with use of the system of King et al. has become widely accepted since its introduction. The purpose of the present study was to establish the interobserver reliability and intraobserver reproducibility of this classification system. The preoperative radiographs of sixty-three patients who were managed operatively for adolescent idiopathic scoliosis were classified by five observers with the system of King et al. Interobserver reliability was assessed by comparison of the classification of the curves among the observers, and intraobserver reproducibility was evaluated by comparison of the classifications of each set of radiographs by each observer on two occasions three weeks apart. The median interobserver reliability kappa coefficient for the classification system of King et al. was 0.44 (range, 0.28 to 0.50), and the median intraobserver reproducibility kappa coefficient was 0.64 (range, 0.44 to 0.72). According to the definition of Landis and Koch, the classification system of King et al. is substantially reproducible but is only moderately reliable. However, according to the stricter definition of Svanholm et al., its reproducibility is only fair and its reliability is poor.

Adolescent↗
PubMed1994

Is it necessary to decorticate segmentally instrumented spines to achieve fusion?

STUDY DESIGN: The effects of spinal instrumentation and decortication on spinal arthrodesis rates--when performed independently and when used together--were studied in an experimental animal model. MATERIALS AND METHODS: Fifty-two immature New Zealand white rabbits underwent six different spinal procedures. The animals were killed six weeks postoperatively and their spines were evaluated by gross examination, radiography, manual stress testing, and histologic means. RESULTS: The addition of rigid instrumentation to autologous iliac grafting significantly improved fusion rates in animals that were not decorticated. However, when decortication was done, a statistically significant improvement could not be documented. The addition of decortication to autologous iliac grafting significantly improved fusion rates in noninstrumented spines, but in instrumented spines, a statistically significant improvement could not be demonstrated.

Animals↗
PubMed1991

Ankle arthrodesis in children.

The indications, surgical technique, and long-term functional results for ankle arthrodesis differ between children and adults. In children, the reasons for performing a tibiotalar fusion include pain, most commonly from traumatic and septic arthritis, and instability from congenital anomalies or paralytic disorders. The most appropriate procedure is Chuinard's fusion, which achieves a tibiotalar fusion without causing a growth arrest of the distal tibial growth plate. In the long term, young patients with ankle arthrodesis function very well with minimal pain or disability. Stressful activities such as hill climbing, stair climbing, and running may be restricted or require compensatory movements.

Ankle Joint↗
PubMed1990

Swing-through vs. reciprocating gait patterns in patients with thoracic-level spina bifida.

Three thoracic level spina bifida patients were evaluated in a gait laboratory. The patients first were asked to walk with a swing-through gait pattern using conventional hip-knee-ankle-foot orthosis and then with a reciprocating gait pattern using the reciprocating gait orthosis (RGO). The reciprocating gait was modestly more efficient than the swing-through gait pattern. The average speed of free walking was 11.4 meters per minute with the swing-through pattern and 16.2 meters per minute with the reciprocating pattern. The stride length was 0.31 meters and 0.54 meters with the swing-through and reciprocating patterns respectively. The RGO needs further modifications to improve the walking ability of spina bifida patients. The hip joints permit only flexion and extension and no rotational movement. The lack of internal and external rotation inhibits hip movement, reduces stride length, reduces the speed of walking and causes the cables to bind and eventually break. With design changes, future bracing systems will permit improved walking in the high level spina bifida patients.

Braces↗
PubMed1989

The cavovarus foot deformity. Etiology and management.

The cavovarus foot is a complex deformity of the forefoot and hindfoot, frequently of neuropathologic etiology. A progressive spinal or peripheral neuromuscular disorder must be excluded by a thorough clinical evaluation. With the failure of nonoperative modalities, surgical options depend on patient age, etiology of the deformity, and the constellation and flexibility of the defects observed. If the hindfoot varus is flexible, correction of the cavus and forefoot pronation through extensive plantar release and metatarsal osteotomies is reliable. The underlying muscle imbalance must be addressed through tendon transfers to prevent further progression. In the young child, a rigid hindfoot varus will often be corrected by a radical plantar-medial release, but the more mature foot may require midtarsal osteotomy and calcaneal osteotomy or triple arthrodesis. The surgery is usually staged to provide correction of deformity and stabilization of the hindfoot prior to tendo Achilles lengthening or tendon transfer. Arthrodesis of a previously well-corrected foot is common due to progression of the neurologic deficit or failure to achieve muscular balance. The claw toe deformity also must be corrected by tendon transfer, osteotomy, and arthrodesis for reasons of both comfort and function.

Foot Deformities↗
PubMedDate not supplied

A randomized comparison of the effects of continuous thoracic epidural analgesia and intravenous patient-controlled analgesia after posterior spinal fusion in adolescents.

BACKGROUND AND OBJECTIVES: Pain and gastrointestinal dysfunction are primary factors that delay recovery after posterior spinal fusion. Previous reports suggest that the choice of analgesic management may effect the course of recovery. This prospective, randomized study compared continuous thoracic epidural analgesia and patient-controlled analgesia in the postoperative care of adolescents undergoing posterior spinal fusion for idiopathic scoliosis. METHODS: Patients between 11 and 18 years of age were randomized to receive continuous thoracic epidural analgesia with bupivacaine-fentanyl (CEA, n = 17) or intravenous patient-controlled analgesia with morphine sulfate (n = 16). After surgery under general anesthesia, pain intensity was evaluated using a self-report visual analog scale (VAS). Postoperative time to resumption of bowel sounds, liquid intake, and side effects were also recorded. RESULTS: There were no significant differences between groups in VAS pain scores, side effects, or time to resumption of liquid intake. There was a significant difference (P = .0089) between groups in return of bowel sounds, which occurred earlier in patients receiving CEA. CONCLUSIONS: Continuous epidural analgesia and patient-controlled analgesia are comparably effective and safe after posterior spinal fusion. Return of bowel sounds occurred significantly more rapidly in patients receiving CEA postoperatively.

Adolescent↗
PubMedDate not supplied

Infantile dislocation of the elbow complicating obstetric palsy.

This is a report of three cases of complete dislocation of both the radius and ulna at the elbow in infants born with obstetric palsy. All three patients had painless elbow-flexion contractures. The pathologic anatomy included (a) medial and posterior displacement of the radius and ulna on the humerus, (b) laxity of the lateral capsule and collateral ligaments, (c) contracted medial capsule and collateral ligaments, (d) contracted biceps and triceps muscles, and (e) hypoplasia of the capitellum, trochlea, coronoid process, and olecranon fossa. Open reduction was attempted in all three of these patients and was successful in two.

Birth Injuries↗
PubMedDate not supplied

Femoral neck fracture secondary to in situ pinning of slipped capital femoral epiphysis: a previously unreported complication.

Two patients developed femoral neck fractures as a complication of in situ pinning for slipped capital femoral epiphysis (SCFE) by surgeons who each used a cannulated screw system. Both patients exhibited recurrent hip pain, femoral neck fracture, and coxa vara after asymptomatic postoperative intervals of 2 and 6 months, respectively. The fracture in one patient healed with weight relief alone: the other persisted, requiring a vascularized pedicle bone graft. Bone biopsy at surgery disclosed avascular necrosis (AVN). Based on preliminary studies of heat production during reaming, we speculate that these fractures developed through areas of AVN secondary to thermal injury.

Adolescent↗
PubMedDate not supplied

The popliteal artery entrapment syndrome in children.

This article reviews 41 cases of the popliteal artery entrapment syndrome in individuals less than 20 years of age. In this syndrome, symptoms are caused by vascular insufficiency produced by either an anomalous course of the popliteal artery or anomalous muscles impinging upon it. Because vascular insufficiency is uncommon in orthopedic patients in this age group and this syndrome has received little attention in the orthopedic literature, orthopedists unfamiliar with this relatively easily diagnosed condition may miss it.

Adolescent↗
PubMedDate not supplied

Fat embolism as a complication of closed femoral shortening.

Although closed femoral osteotomy for shortening or correction of deformity is not a new procedure, its popularity apparently is increasing. We have encountered a serious "biological" complication that should be considered before this technique is selected. Two patients, a 12-year-old girl and an 18-year-old man, developed findings consistent with the fat embolism syndrome after closed femoral shortening. We suggest consideration of postoperative monitoring with pulse oximetry of patients undergoing this procedure.

Adolescent↗
PubMedDate not supplied

Femoral head avascular necrosis associated with intramedullary nailing in an adolescent.

An adolescent developed avascular necrosis of the femoral head after intramedullary nailing for a femoral diaphyseal fracture. This complication is most likely secondary to injury to the posterior superior ascending branch of the medial circumflex artery at the time of rod insertion. This artery is situated close to the proximal insertion hole just posterior to the trochanteric notch and piriformis fossa. Other methods of fracture treatment, either operative or nonoperative, should be considered in skeletally immature patients.

Adolescent↗
PubMedDate not supplied

An evaluation of the Adams forward bend test and the scoliometer in a scoliosis school screening setting.

We examined the ability of the Adams forward bend test and the scoliometer to detect truncal rotation or asymmetry in a school screening setting. Of 954 sixth graders examined with each test independently, 123 and 13 [using an angle of trunk rotation (ATR) of > 5 and 7 degrees, respectively] were found to be abnormal on scoliometer examination but appeared normal on the Adams test. Selecting children for scoliometer examination on the basis of the Adams test is not supported by our data and may not be consistent with generally accepted principles of public health screening.

Child↗