The physico-chemical characterization of a boiling stable antifreeze protein from a perennial grass (Lolium perenne).

We have characterized a cold-induced, boiling stable antifreeze protein. This highly active ice recrystallization inhibition protein shows a much lower thermal hysteresis effect and displays binding behavior that is uncharacteristic of any AFP from fish or insects. Ice-binding studies show it binds to the (1 0 1 0) plane of ice and FTIR studies reveal that it has an unusual type of highly beta-sheeted secondary structure. Ice-binding studies of both glycosylated and nonglycosylated expressed forms indicate that it adsorbs to ice through the protein backbone. These results are discussed in light of the currently proposed mechanisms of AFP action.

Understanding the mechanism of ice binding by type III antifreeze proteins.

Type III antifreeze proteins (AFPs) are present in the body fluids of some polar fishes where they inhibit ice growth at subzero temperatures. Previous studies of the structure of type III AFP by NMR and X-ray identified a remarkably flat surface on the protein containing amino acids that were demonstrated to be important for interaction with ice by mutational studies. It was proposed that this protein surface binds onto the (1 0 [\bar 1] 0) plane of ice with the key amino acids interacting directly with the water molecules in the ice crystal. Here, we show that the mechanism of type III AFP interaction with ice crystals is more complex than that proposed previously. We report a high-resolution X-ray structure of type III AFP refined at 1.15 A resolution with individual anisotropic temperature factors. We report the results of ice-etching experiments that show a broad surface coverage, suggesting that type III AFP binds to a set of planes that are parallel with or inclined at a small angle to the crystallographic c-axis of the ice crystal. Our modelling studies, performed with the refined structure, confirm that type III AFP can make energetically favourable interactions with several ice surfaces.

Current trends in the treatment of femoral shaft fractures in children and adolescents.

Healthcare cost containment and a desire for early discharge of the pediatric patient to the home environment have become important factors in the treatment of femoral shaft fractures in children. As a result, newer techniques of treatment have become popular. The immediate hip spica cast remains the primary method of treatment for most children 6 years of age and younger. The treatment for children between the ages of 6 and 10 years is the most controversial. Many such patients may be treated successfully with immediate hip spica casts. However, external fixation and flexible intramedullary rod fixation are being used more frequently, particularly in patients with multiple trauma. The initial enthusiasm for rigid intramedullary rod fixation of adolescent femoral fractures has been tempered by recent reports of femoral head avascular necrosis. Avoiding the piriformis fossa during rod insertion may prevent this complication. Most children and adolescents with femoral fractures can be treated successfully with a brief hospital course without compromising care or outcome.

Shortening in femoral shaft fractures in children treated with spica cast.

Early spica cast treatment is one method used for children's femoral shaft fractures; it is increasingly advocated as treatment that allows early hospital discharge. The outcome of early spica cast treatment in 100 children, ages 2 to 10 years, with uncomplicated and isolated closed femoral shaft fractures treated at Johns Hopkins Hospital between October 1987 and March 1994 were analyzed. The objective was to identify those children who can be treated safely and dependably with early spica casting without excessive shortening of the fracture fragments. Eighty-one (81%) children had an acceptable outcome and 19 (19%) had an unacceptable outcome by the definition of more than 25 mm of fracture fragment overlap after clinical healing. A new clinical test, the telescope test, was statistically significant for correlation with spica cast outcome. Age, gender, fracture, location, mechanism of injury, fracture type, and resting radiograph of fracture fragment overlap were not statistically significant. The telescope test had a sensitivity of 80% and a specificity of 85% for predicting outcome. The relative risk for failure of spica cast treatment with a positive telescope test was 20.4 (95% confidence limits = 2.7-225.1). Children 2 to 10 years of age with uncomplicated femoral shaft fractures and a negative telescope test can be treated appropriately in most cases with early application of a spica cast.

Lymph node metastases and prognosis in patients with stage IA2 cervical cancer.

Ninety-four patients with squamous cell carcinoma invading the cervical stroma to a depth of >3.0-5.0 mm with 7 mm or less in horizontal spread (FIGO Stage IA2) were evaluated. Depth and lateral extent of stromal invasion were verified using an ocular micrometer. Cell type and lymph vascular space invasion (LVSI) were recorded in each case. Patients were treated primarily by radical hysterectomy with pelvic lymphadenectomy, and those with lymph node metastases were offered postoperative radiation. Following treatment, patients were seen at 3-month intervals for 2 years, and every 6 months thereafter. The mean duration of follow-up was 6.9 years (range 0.4-23.5 years). Seven of 94 patients (7.4%) had lymph node metastases. Five patients had 1 positive node, 1 patient had 2 positive nodes, and 1 patient had 3 positive nodes. Five patients developed recurrent cancer and 4 died of disease. LVSI was present in 31 cases (33%). Tumor recurrence was significantly increased in patients with positive LVSI (9.7% vs 3.2%). The 5-year survival rate of patients with LVSI was 89% vs 98% in patients without this finding (P = 0.058). The 5-year survival rate of all Stage IA2 cervical cancer patients was 95%. Patients with Stage IA2 cervical cancer have a significant risk of lymph node metastases and should be treated by radical hysterectomy with pelvic lymphadenectomy. LVSI is an important prognostic variable in these patients and should be recorded in all cases.

Severe (type III) open fractures of the tibia in children.

Twenty children with acute type III open fractures of the tibial metaphyses or diaphysis were retrospectively studied. The average age was 9 years, 1 month (range, 2 years, 11 months to 16 years, 2 months). There were seven type IIIA fractures, 10 type IIIB fractures, and 3 type IIIC fractures. All fractures were irrigated and debrided, and prophylactic antibiotics were given for a minimum of 48 h. Fifteen fractures were initially treated with external fixation, three with casts, one with internal fixation, and one with a combination of external fixation and limited internal fixation. Free muscle flaps were used for soft-tissue coverage in six patients, and a local muscle flap in one patient. The average time to fracture healing was 29 weeks, and the median time to fracture healing was 20 weeks (range, 8-104). Four patients had delayed union, and two additional patients had nonunion. Both patients with nonunion were successfully treated with autologous bone grafting. The time to fracture union was related to the severity of soft-tissue injury, fracture configuration, segmental bone loss, and infection. Osteomyelitis developed in three patients. All were successfully treated. Two patients treated with external fixation had leg-length discrepancies of > 1 cm, with the injured extremity longer in both cases. There were no late amputations. Children with severe open fractures of the tibia have a good prognosis for limb salvage with aggressive wound care and fracture management.

Benign pelvic masses: sonographic spectrum.

Detection and characterization of pelvic masses are universal and vital applications of sonography. Despite the considerable overlap in the morphologic patterns of different pelvic masses, a characteristic sonographic appearance frequently allows at least a narrow differential diagnosis and often allows a specific diagnostic choice, particularly when the imaging findings are coupled with sufficient clinical data. Color flow and spectral Doppler techniques are evolving and have promising roles in diagnosis of pelvic masses; however, basic sonographic morphology coupled with the necessary clinical input remains the mainstay of sonographic differential diagnosis of pelvic masses. Considerable research is being done on enhancing sonographic differentiation between benign and malignant neoplasms. The most common sonographic features of benign pelvic masses should permit clinically useful characterization. Benign pelvic masses include uterine masses (leiomyoma, hematometra, hematocolpometra), ovarian masses (functional cysts, polycystic ovaries, parovarian cyst, endometrioma, epithelial tumors, dermoid cyst), and miscellaneous masses (pelvic inflammatory disease, ectopic pregnancy).

Ligamentous instability of the knee in children sustaining fractures of the femur: a prospective study with knee examination under anesthesia.

Fifty-five children with 55 fractures of the femur were prospectively studied for the presence of ligamentous instability of the knee within 3 weeks from the time of injury. Two patients (4%) demonstrated instability on examination under anesthesia. A 9-year, 4-month-old boy sustained a second-degree injury to the lateral collateral ligament that healed after hip spica cast treatment. The other patient, a 12-year, 8-month-old boy, sustained an avulsion fracture of the posterior cruciate ligament from the tibial insertion with > 1 cm posterior displacement of the tibia on the posterior drawer test. After placement of an intramedullary rod, the avulsion fracture was treated with open reduction and internal fixation. Although the incidence of ligamentous instability of the knee in this study is less than that reported for adults with femur fractures, children should nevertheless have a thorough knee examination for ligamentous stability as well as radiographic evaluation of the knee.

Stress fractures of the femoral diaphysis in young children. A report of 2 cases.

Stress fractures of the femoral diaphysis in young children are rare. Pain and an antalgic gait are the most common features. There is usually no history of either trauma or a recent increase in physical activities. Initial radiographs may be normal. Technetium bone scanning is the most sensitive method of early diagnosis, but may not be diagnostic. Computed tomography and magnetic resonance imaging are useful in early confirmation of the diagnosis. Serial radiographs will show maturation of the periosteal new bone with evidence of repair. Biopsy should be avoided, except in cases of obvious neoplasm shown by computed tomography or magnetic resonance imaging, or in cases with progressive cortical destruction shown on serial radiographs, because fracture callus may be difficult to distinguish from osteosarcoma. Treatment consists of protected weight bearing and activity restriction until resolution of symptoms and radiographic evidence of healing.

A prospective study of early spica casting outcomes in the treatment of femoral shaft fractures in children.

We analyzed the early spica casting outcomes of 50 children age 2 to 10 years with uncomplicated femoral shaft fractures treated at Johns Hopkins Hospital between October 1987 and October 1990. Our objective was to develop criteria for the prospective identification of patients who can be safely and dependably treated with early spica casting without excessive shortening of the fracture fragments. Forty-one (82%) children had an acceptable outcome and nine (18%) had an unacceptable outcome according to our definition of > 25 mm of fracture fragment overlap at 3 to 4 weeks follow-up. A new clinical test, the telescope test, was statistically significant (p < 0.001) for association with spica casting outcome. Age, sex, fracture location, mechanism of injury, fracture type, and resting roentgenogram fracture fragment overlap were not statistically significant (p > 0.10). The telescope test had a sensitivity of 78%, a specificity of 85%, and a negative predictive value of 95% for predicting spica casting outcome. The relative risk of failing spica casting after a positive telescope test was 20.4 (95% CI, 2.74-225.10). We conclude that children 2 to 10 years of age with uncomplicated femoral shaft fractures and a negative telescope test can be safely treated with early spica casting and have a 95% change of having a successful outcome with this treatment.

Analgesia for the reduction of fractures in children: a comparison of nitrous oxide with intramuscular sedation.

A prospective, randomized study was undertaken to compare the effectiveness of nitrous oxide with intramuscular sedation (meperidine and promethazine) in providing analgesia and amnesia during the reduction and treatment of children's fractures in an outpatient clinic setting. Fifteen patients received a 50:50 mixture of nitrous oxide and oxygen, and 15 received intramuscular injection. The two groups were similar in regard to gender distribution, age, and fracture types. Pain response was recorded using the Children's Hospital of Eastern Ontario (Canada) Pain Scale (CHEOPS) at the time of fracture reduction and 30 min postreduction. At the first follow-up visit a questionnaire regarding the patient's memory and subjective experience of the fracture reduction was answered. Data between the two groups were compared using the Mann-Whitney test. The CHEOPS scores, and the memory and subjective experience of the fracture reduction were similar between the two groups. Time in the outpatient department averaged 83 min for the intramuscular group and 30 min for the nitrous oxide group (p < 0.01). All of the nitrous oxide patients stated they would use nitrous oxide again, whereas only eight of 15 intramuscular patients stated they would try intramuscular sedation again. Nitrous oxide is as effective as intramuscular sedation in providing analgesia and amnesia in the treatment of children's fractures while having a more rapid onset and a shorter recovery period with greater patient acceptance.

Therapeutic implications of lymph nodal spread in lateral T1 and T2 squamous cell carcinoma of the vulva.

From 1963 to 1993, 157 patients with primary squamous cell carcinoma of the vulva were treated by radical surgery at the University of Kentucky Medical Center. There were 84 unilateral lesions confined to the labium majus or labium minus. Thirty-seven patients had T1 lesions, median diameter 1.5 cm (range 0.5-2.0 cm), and 47 patients had T2 lesions, median diameter 3.4 cm (range 2.2-9.0 cm). Radical vulvectomy with bilateral inguinal lymphadenectomy was performed in 56 patients and radical hemivulvectomy with selective inguinal lymphadenectomy in 28 patients. An average of 8 nodes was removed with superficial inguinal lymphadenectomy and 13 nodes with superficial and deep inguinal lymphadenectomy. Deep inguinal lymph node metastases occurred only in patients with positive superficial inguinal lymph nodes. There were no contralateral inguinal lymph node metastases in any lateral T1 or T2 lesion. Following surgery, patients were followed 1-15 years (mean 5.0 years) and none have been lost to follow-up. Nine patients developed ipsilateral recurrences, but no contralateral recurrences were noted. Seven of these patients developed local recurrences to the ipsilateral vulvar skin and were cured by reexcision. Two patients (2.4%), both of whom had positive ipsilateral superficial and deep inguinal lymph node metastases at the time of initial surgery, developed distant metastases and died of disease 10 and 11 months after treatment. These data suggest that deep inguinal lymph nodal metastases occurred only in patients with superficial inguinal node involvement. Contralateral inguinal lymph nodal metastases are extremely rare in lateral T1 and T2 vulvar squamous cell carcinomas. Radical hemivulvectomy is as effective as radical vulvectomy in the treatment of lateral T1 and T2 vulvar squamous cell cancers.

The relationships of skeletal injuries with trauma score, injury severity score, length of hospital stay, hospital charges, and mortality in children admitted to a regional pediatric trauma center.

Thirty-four-hundred and seventy-two children were consecutively admitted for acute traumatic injuries over a 34 month period to the Children's National Medical Center. The study comprised 805 patients who sustained 953 fractures and dislocations. The male to female ratio was 2:1. Age at the time of admission was evenly distributed over 16 years, with a mean of 8.3 years. Pedestrian accidents and falls each accounted for 34% of the musculoskeletal injuries, whereas motor vehicle accidents accounted for an additional 13%. The femur was the most commonly fractured bone, representing 22% of all fractures and dislocations, followed by the humerus (16%), tibia/fibula (12%), ankle/foot (13%), and radius/ulna (8%). Nine percent of the fractures were open. The average length of hospital stay was 8.6 days, and the average cost per hospital admission was $8,765. The mortality rate was 3%. Central musculoskeletal injuries (spine, clavicle/scapula, and pelvis) in our hospitalized patients were associated with the longest hospital stays and intensive care unit admissions, and lowest Trauma Scores, as well as the highest Injury Severity Scores, hospital charges, and mortality rates.

Sports injuries in children.

More children are participating in organized sports than ever before. Although improved coaching, equipment, officiating, and rules have been implemented to reduce injuries, a significant number of young athletes continue to be injured. Fortunately, most injuries sustained by young athletes are minor requiring only symptomatic treatment. However, because of the unique features of the immature skeleton, particularly the presence of open physes, these injuries can nonetheless result in permanent alteration of bone growth with long-term morbidity and disability. Furthermore, the prognosis and natural history of sports injuries in children may be different than that for similar injuries in adults. It is important that the practitioner dealing with young athletes be aware of the unique features of children's sports injuries so that proper treatment may be initiated and prognosis and expected outcome may be intelligently discussed with the patient and parents. This review provides current information regarding sports injuries in children by summarizing the most recent pertinent articles.

Osteotomy of the proximal tibia in the treatment of adolescent tibia vara.

Between 1983 and 1990, 9 patients with 13 involved lower extremities had proximal tibial osteotomies for the treatment of adolescent tibia vara. Average age at the time of onset was 11 years, 8 months. All patients were black and obese. The interval between awareness of the bowleg deformity and presentation averaged 1.7 years. The mean preoperative tibiofemoral angle was 13 degrees varus. Stabilization was achieved by external fixation (6 extremities), crossed pins (4 extremities), or staples (3 extremities). One patient with bilateral deformity experienced multiple postoperative complications including osteomyelitis and recurrent varus deformity at the osteotomy sites, both successfully treated. Another patient had recurrence of the varus deformity and a leg-length discrepancy secondary to early closure of the medial proximal tibial physis. At an average follow-up of 4 years, two patients complained of occasional pain; none complained of pain that restricted normal activities. The mean improvement in the tibiofemoral angle at follow-up was 20 degrees, with a mean tibiofemoral angle of 6 degrees valgus. Overall, there were 10 good, no fair, and 3 poor results.

Focal scleroderma in children: an orthopaedic perspective.

Focal scleroderma is a connective-tissue disorder manifested by fibrosis of the skin and subcutaneous tissues. Consequently, it may be associated with joint contractures, extremity deformity, and impairment of extremity function. It has a variable clinical course, with both remissions and recurrences. In resistant cases of extremity involvement, treatment considerations should include physical and occupational therapy, medical treatment, bracing, serial casting, and surgical intervention. We reviewed seven patients treated between 1960 and 1990 with significant joint contractures secondary to focal scleroderma. Serial casting was found to be useful for contractures about the wrist, knee, and ankle. Soft-tissue release was an effective treatment for contractures at the wrist, hip, and ankle. Knee disarticulation was performed on one patient with a severe knee-flexion contracture. Epiphysiodesis and femoral shortening osteotomy were effective treatments for leg-length equalization in a case of hemiatrophy.

Advanced ovarian carcinoma diagnosed during pregnancy in a patient with human immunodeficiency virus infection.

Many malignancies appear to occur with increased frequency and aggressive patterns of spread in patients seropositive for human immunodeficiency virus (HIV). The relationship between HIV infection and cervical neoplasia suggests that these patients present with more advanced disease and demonstrate poor response to therapy. To date, there have been no reported cases of ovarian cancer with concomitant HIV infection. We describe a young, gravid woman with an advanced ovarian carcinoma diagnosed at the time of delivery. Following poor response to cytoreductive surgery and initial chemotherapy, she was found to be HIV-seropositive. She received multiple chemotherapeutic regimens and experienced significant complications associated with her treatment and HIV infection. She progressively deteriorated and died within 13 months of diagnosis. Based on these findings and experience with other HIV-associated malignancies, it is apparent that the conventional approach to therapy is inadequate to treat the advanced and more aggressive form of disease seen in women infected with HIV.

Surgical failures in the management of pelvic floor relaxation.

There are a vast number of operations for the correction of symptomatic pelvic floor relaxation, and the pelvic surgeon is faced with a difficult task in selecting the most appropriate procedure(s) for an individual patient. A successful outcome not only depends on the surgeon's skill and operative technique, but also relies heavily on the preoperative recognition and evaluation of factors related to surgical failure. Most importantly, careful attention to all components of the pelvic floor will allow the surgeon to tailor an operation to the individual's particular needs. Awareness of the many pitfalls of pelvic reconstructive surgery should lead to the appropriate preoperative evaluation and patient counseling, thus ensuring the best opportunity for a favorable outcome.

Upper extremity restraint during hip spica cast application.

Control of the upper extremities of a sedated or anesthetized patient can be a cumbersome and difficult problem during hip spica cast application. To overcome this, we developed a simple technique to control the upper extremities without placing the neurovascular structures under tension while allowing easy venous access for the anesthesia personnel. Use of a simple armboard made of supplies commonly available in the cast room has made this possible. The construction and clinical use of this armboard is described. It has been used successfully for > 12 months at the authors' institution with no untoward effects.

Arthroscopic surgery of the knee on the U.S. Naval Hospital Ships during Operation Desert Shield.

Between September 1990 and January 1991, while deployed to the Persian Gulf for Operation Desert Shield, 118 patients underwent arthroscopic surgery of the knee on the U.S. Naval Hospital Ships USNS Mercy and USNS Comfort. There were 113 men and 5 women, with an average age of 28 years (range, 19-59 years). The most common findings at the time of arthroscopy were meniscus tears (53%), anterior cruciate ligament tears (29%), and normal arthroscopic examinations (9%). There were three complications, two hemarthroses and one superficial portal site infection. Seventy patients (59%) were able to be returned to duty at an average of 6 days post-operatively, obviating the need to evacuate these patients out of the Middle East theater to Europe or the United States, thus avoiding additional delay, expense, and loss of the service member to his military unit.