Studies in NZB IL-10 knockout mice of the requirement of IL-10 for progression of B-cell lymphoma.

NZB mice develop an age-related malignant expansion of a subset of B cells, B-1 cells, with autocrine production of IL-10. IL-10, a pleiotropic cytokine with anti-inflammatory properties, is a potent growth and survival factor for malignant B cells. To further examine the in vivo requirement for IL-10 in the development and expansion of malignant B-1 clones in NZB mice, we developed a strain of homozygous IL-10 knockout (KO) mice on an NZB background. The NZB IL-10 KO mice develop peritoneal B-1 cells with approximately the same frequency as heterozygous and wild-type littermates. In contrast, the development of malignant B-1 cells in the peripheral blood and spleen, observed in wild-type NZB, rarely occurred in the NZB IL-10 KO. Phenotypic analysis of surface marker expression in splenic B cells indicated that, in contrast to the NZB with malignant B-1 splenic lymphoma, the surface marker expression of NZB IL-10 KO splenic B cells indicated that the majority of the B cells were typical B-2 cells. In the absence of IL-10, spontaneously activated B cells and antiapoptotic gene expression were reduced and lymphoma incidence was decreased. These results indicate that IL-10 is a critical factor for the progression of this B-cell malignant disease.     

Angiogenesis is an early event in the development of chemically induced skin tumors

In this study we have analyzed the vascular response induced in the two- stage carcinogenesis model in SENCAR mice. The role of angiogenesis has not been explored in this model, which is the paradigm of multistage carcinogenesis and a model for neoplastic lesions derived from exophytic premalignant lesions (e.g. colon carcinoma, bladder papilloma). We investigated if angiogenesis is involved in the formation of papillomas and in the progression from papilloma to carcinoma. To this end we analyzed the vasculature of normal and hyperplastic skin, focal epidermal hyperplasias that are precursors of papillomas, papillomas at different stages and squamous cell carcinomas. We also analyzed the vascularization of papillomas induced in two strains of mice that differ in their susceptibility to malignant progression. We show here that angiogenesis is turned on in the earliest stages of papilloma formation. In late stages, regardless of state of progression, the predominant response is an increase in the size of blood vessels. Thus, in the SENCAR mouse model, representative of exophytic tumors, the angiogenesis switch is a very early event, probably mechanistically related to the development of the primarily exophytic lesions. Therefore, the density of blood vessels cannot be used as a predictor of malignant progression in this model.      

Telangiectatic dedifferentiation of a parosteal osteosarcoma

A unique case of parosteal osteosarcoma (POS) of the proximal femur, with areas of telangiectatic dedifferentiation, in a 28-year-old woman is reported. The patient had a 7-week history of pain and swelling in her right thigh. A biopsy diagnosis of POS was established. The patient was treated with two cycles of intra-arterial chemotherapy, followed by limb salvage surgery. Histological examination of the resected specimen showed POS with areas of dedifferentiation composed of high-grade telangiectatic osteosarcoma with associated secondary aneurysmal bone cyst change. Received: 17 April 1998 Revision requested: 11 May 1998 Revision received: 9 May 2000 Accepted: 11 May 2000     

The laryngeal mask for percutaneous endoscopic gastrostomy

IMPLICATIONS: We report the successful use of the laryngeal mask airway for percutaneous endoscopic gastrostomy in an adult patient with a known difficult airway and severe cerebral palsy.     

Short-term wound complications after application of flaps for coverage of traumatic soft-tissue defects about the tibia. The Lower Extremity Assessment Project (LEAP) Study Group

BACKGROUND: The purpose of the present study was to compare the rate of short-term wound complications associated with rotational flaps and that associated with free flaps for coverage of traumatic soft-tissue defects about the tibia. METHODS: Of 601 patients prospectively enrolled in a multicenter study of high-energy trauma of the lower extremity, 190 patients (195 limbs) required flap coverage and had six months of follow-up. The injury data included the ASIF/OTA classification of the tibial fracture and the soft-tissue injury and the functional status of the neurovascular and muscular structures of the soft-tissue compartments at the time of soft-tissue coverage. The treatment data consisted of the type of flap, the timing of the flap coverage, and the type of fixation. The patient characteristics that were recorded included the age, gender, presence of comorbidities, and smoking status at the time of the injury. Short-term complications included wound infection, wound necrosis, and loss of the flap within the first six months after the injury. RESULTS: Eighty-eight limbs were treated with a rotational flap, and 107 limbs were treated with a free flap. Overall, complications occurred after fifty-three (27 percent) of the 195 flap procedures; forty-six (87 percent) of the fifty-three required operative treatment. The two treatment groups were similar with respect to age, gender, comorbidities, preinjury smoking status, ASIF/OTA classification of the fracture, and prevalence of vascular injury requiring repair (p>0.05). There were two important differences between the two groups. First, three of the four leg compartments--that is, the anterior, lateral, and deep posterior compartments--were more likely to be functionally compromised in the free-flap group than in the rotational flap group (p<0.05), suggesting that patients in the free-flap group had sustained more severe soft-tissue injuries. Second, the Injury Severity Score was significantly higher (p = 0.001) in the rotational flap group (mean, 14 points) than in the free-flap group (mean, 11 points), suggesting that patients in the former group had sustained more substantial total body trauma. Overall, there were no significant differences between the two groups with respect to the complication rates. However, among those with the most severe grade of underlying osseous injury (an ASIF/OTA type-C injury), 44 percent of the limbs that were treated with a rotational flap had a wound complication compared with 23 percent of the limbs that were treated with a free flap (p = 0.10). To control for any differences between the two groups with respect to the severity of the injury, the treatment methods, or the patient characteristics, multivariate regression modeling was performed. An interaction effect between the type of flap and the severity of the underlying osseous injury demonstrated significance (p<0.05) after controlling for other factors. Of the limbs that sustained an ASIF/OTA type-C osseous injury, those that were treated with a rotational flap were 4.3 times more likely to have a wound complication requiring operative intervention than were those treated with a free flap. No significant difference in the rate of complications was detected with respect to the type of flap used for the limbs that had lower-grade osseous injuries. CONCLUSIONS: We found that use of a free flap to treat limbs with a severe underlying osseous injury was significantly less likely to lead to a wound complication requiring operative intervention than was use of a rotational flap.     

Fibular hemimelia: comparison of outcome measurments after amputation and lengthening

BACKGROUND: Treatment of fibular hemimelia includes either Syme or Boyd amputation with early prosthetic fitting or tibial lengthening. Numerous studies have documented the success of both procedures. The purpose of our study was to compare the outcome after amputation with that after tibial lengthening, specifically with regard to activity restrictions, pain, satisfaction, complications, number of procedures, and cost, in children with fibular hemimelia. METHODS: Thirty limbs in twenty-five patients treated with either an amputation or a lengthening procedure and followed for at least two years were studied. Fifteen patients underwent amputation, and ten patients underwent lengthening of the tibia. The mean age was 1.2 years at the time of amputation and 9.7 years at the time of initial lengthening. The mean duration of follow-up was 6.9 years after the amputations and 7.1 years after the lengthening procedures. RESULTS: The patients who underwent amputation were able to perform more activities than those who had a lengthening (mean activity score, 0 compared with 1.2 points; p<0.05), and they had less pain (mean pain score, 0.2 compared with 1.2 points; p = 0.091), were more satisfied and had a lower complication rate (0.37 compared with 1.91; p<0.05). The patients who underwent amputation also had fewer procedures (1.9 compared with 7.0; p<0.05), at a lower cost ($7016 compared with $26,900; p<0.05), than those who had a lengthening. Lengthening was successful in equalizing limb lengths; the mean limb-length discrepancy, assessed in nine of eleven limbs, was 0.7 centimeter. CONCLUSIONS: This study demonstrated that children who undergo early amputation are more active, have less pain, are more satisfied, have fewer complications, undergo fewer procedures, and incur less cost than those who undergo lengthening. This was true even though good results were obtained with the lengthening procedures and most patients achieved limb-length equality, were able to walk, had minimal pain, and were quite active.     

异位妊娠

异位妊娠是指发生于子宫以外的妊娠。其中绝大部分（98％）发生于输卵管，而卵巢、宫颈、腹腔也可发生，但较为罕见。异位妊娠占妊娠总数的1／150，发生率较20年前提高了4倍。     

Aortic valve repair after arterial switch operation

A patient with transposition of the great arteries and a ventricular septal defect underwent an arterial switch operation 15 months after pulmonary artery banding. At 12 years of age, severe neoaortic valve regurgitation, due to dilated aortic sinuses and poor leaflet coaptation, developed. Aortic valve repair involved placement of subcommissural sutures, elliptical excision and tailored reduction of two anterior aortic sinuses, with triangular patch expansion of the proximal ascending aorta. A good result was obtained.     

Temperature-dependent pharmacokinetics and pharmacodynamics of vecuronium

BACKGROUND: The authors evaluated the influence of temperature on the pharmacokinetics and pharmacodynamics of vecuronium because mild core hypothermia doubles its duration of action. METHODS: Anesthesia was induced with alfentanil and propofol and maintained with nitrous oxide and isoflurane in 12 healthy volunteers. Train-of-four stimuli were applied to the ulnar nerve, and the mechanical response of the adductor pollicis was measured. Volunteers were actively cooled or warmed until their distal esophageal temperatures were in one of four ranges: < 35.0 degrees C, 35.0-35.9 degrees C, 36.0-36.9 degrees C, and > or = 37.0 degrees C. With temperature stabilized, vecuronium was infused at 5 microg x kg(-1) x min(-1) until the first response of each train-of-four had decreased by 70%. Arterial blood (for vecuronium analysis) was sampled at intervals until the first response recovered to at least 90% of its prevecuronium level. Vecuronium, 20 microg x kg(-1) x min(-1), was then infused for 10 min, and arterial blood was sampled at intervals for up to 7 h. Population-based nonlinear mixed-effects modeling was used to examine the effect of physical characteristics and core temperature on vecuronium pharmacokinetics and pharmacodynamics. RESULTS: Decreasing core temperature over 38.0-34.0 degrees C decreases the plasma clearance of vecuronium (11.3% per degrees C), decreases the rate constant for drug equilibration between plasma and effect site (0.023 min(-1) per degrees C), and increases the slope of the concentration-response relationship (0.43 per degrees C). CONCLUSIONS: Our results show that reduced clearance and rate of effect site equilibration explain the increased duration of action of vecuronium with reducing core temperature. Tissue sensitivity to vecuronium is not influenced by core temperature.