A comparison of screw versus drill and curettage epiphysiodesis to correct leg-length discrepancy

PURPOSE

To compare two common surgical techniques of epiphysiodesis: drill/curettage epiphysiodesis (PDED) versus cross screw epiphysiodesis (PETS). The hypothesis is that the two techniques have similar efficacy but demonstrate differences in length of hospital stay (LOS), time to return to activity and complication rates.

METHODS

A retrospective review of growing children and adolescents less than 18 years old who required an epiphysiodesis with leg-length discrepancy (LLD) of 2 cm to 6 cm with minimum two years of follow-up was conducted. Characteristics including age at surgery, gender, epiphysiodesis location, side, operative time, LOS and hardware removal were compared across treatment groups. LLD, expected growth remaining (EGR) and bone age were determined preoperatively and at most-recent visit. The correction ratio (change in EGR) was calculated along with a 95% confidence interval (CI) to assess if correction in leg length was achieved.

RESULTS

A total of 115 patients underwent epiphysiodesis in the femur (53%), tibia (24%) or a combination (24%). The cohort was 47% male, with a mean age of 12.6 years (7.7 to 17.7) at surgery. Median follow-up was 3.7 years (2.0 to 12.7). In all, 23 patients underwent PETS and 92 patients had PDED. Both treatment groups achieved expected LLD correction. There was no significant difference in median operative time, complication rates or LOS. PETS patients returned to activity at a mean 1.4 months (interquartile range (IQR) 0.7 to 2.1) while PDED patients returned at a mean 2.4 months (IQR 1.7 to 3) (p < 0.001).

CONCLUSION

Effectiveness in achieving expected correction, LOS and operative time are similar between screw and drill/curettage epiphysiodesis. Patients undergoing PETS demonstrated a faster return to baseline activity than patients with PDED.

LEVEL OF EVIDENCE

III.

Multiphasic Helical CT Criteria for Differentiation of Recurrent Neoplasm and Desmoplastic Reaction after Laparoscopic Resection of Renal Mass Lesions

BACKGROUND AND PURPOSE

Differentiation of recurrent neoplasm and desmoplastic reaction following laparoscopic resection of renal mass lesions poses a problem. The usefulness of multiphasic helical CT-generated criteria based on enhancement and morphologic characteristics was investigated.

PATIENTS AND METHODS

The findings in 5 female and 12 male patients aged 29 to 68 years having renal-cell carcinoma (11-38 mm; N = 15) or solitary angiomyolipomas (N = 2) treated by laparoscopic resection (N = 15) or open segmental surgery (N = 2) were analyzed. Multiphasic helical CT was performed in the preenhancement, arterial corticomedullary, parenchymal, and excretory phases generating 2.5- to 7-mm slices.

RESULTS

Both recurrent neoplasms showed median postcontrast enhancement of 119 HU in the arterial corticomedullary phase; the median enhancement of desmoplastic masses was 48 HU. In the parenchymal and excretory phase, recurrent neoplasms showed progressive loss of enhancement, whereas desmoplastic lesions sustained enhancement at about the same level. Recurrent neoplasms presented a defined mass with characteristic spiculation, whereas desmoplastic reaction was characterized by an ill-defined mass with spidery projections extending to abutting fat and residual fascial planes. On 2- to 3-month follow-up scans, recurrent neoplasms showed progressive increases in size and desmoplastic reaction a sharp decrease.

CONCLUSION

Enhancement of the mass at the operative site on arterial corticomedullary-phase CT to >90 HU strongly suggests recurrent renal-cell carcinoma, while progressive decrease in size on 1- to 3-month follow-up CT suggests a desmoplastic reaction.

Dynamics of frequency shifted feedback lasers: simulation studies

The operation of an intracavity frequency shifted feedback (FSF) laser exhibits a remarkable range of properties, some of which have been described previously. Here we report a more complete analysis of the dependence of the output power upon pump-laser power, based on simulations with an extended rate equation model and the use of phase space analysis. The effect of FSF is discussed in detail. The simulation of the operation of a titanium-sapphire laser with FSF reveals five separate regimes of operation, a superset of those observed in experiment. We predict the thresholds for each of these regimes for FSF-lasers with titanium-sapphire or neodymium doped crystals as gain medium.

Identification of Bacillus thuringiensis subsp. kurstaki strain HD1-Like bacteria from environmental and human samples after aerial spraying of Victoria, British Columbia, Canada, with Foray 48B

Aerial applications of Foray 48B, which contains Bacillus thuringiensis strain HD1, were carried out on 9 to 10 May, 19 to 21 May, and 8 to 9 June 1999 to control European gypsy moth (Lymantria dispar) populations in Victoria, British Columbia, Canada. A major assessment of the health impact of B. thuringiensis subsp. kurstaki was conducted by the Office of the Medical Health Officer of the Capital Health Region during this period. Environmental (air and water) and human (nasal swab) samples, collected before and after aerial applications of Foray 48B, both in the spray zone and outside of the spray zone, were analyzed for the presence of strain HD1-like bacteria. Random amplified polymorphic DNA analysis, cry gene-specific PCR, and dot blot DNA hybridization techniques were used to screen over 11,000 isolates of bacteria. We identified bacteria with genetic patterns consistent with those of B. thuringiensis subsp. kurstaki HD1 in 9,102 of 10,659 (85.4%) isolates obtained from the air samples, 13 of 440 (2.9%) isolates obtained from the water samples, and 131 of 171 (76.6%) isolates from the nasal swab samples. These analyses suggest that B. thuringiensis subsp. kurstaki HD1-like bacteria were present both in the environment and in the human population of Victoria prior to aerial applications of Foray 48B. The presence of B. thuringiensis subsp. kurstaki HD1-like bacteria in human nasal passages increased significantly after the application of Foray 48B, both inside and outside the spray zone.

The Livermore experience: Contributions of J. H. Eberly to laser excitation theory

This article summarizes the developing understanding of coherent atomic excitation, as gained through a collaboration of J. H. Eberly with the Laser Isotope Separation Program of the Lawrence Livermore National Laboratory, particularly aspects of coherence, population trapping, multilevel multiphoton excitation sequences, analytic solutions to multistate excitation chains, the quasicontinuum, pulse propagation, and noise. In addition to the discovery of several curious and unexpected properties of coherent excitation, mentioned here, the collaboration provided an excellent example of unexpected benefits from investment into basic research.

Surface exposure of apolipoproteins in high density lipoproteins. I. Reactivities with agarose-immobilized proteases

The exposure of apolipoproteins at the surface of human plasma high density lipoproteins (HDL) was assessed by their accessibility to agarose-immobilized forms of trypsin and chymotrypsin. Proteolysis of lipid-free apolipoproteins and the lipoprotein subfractions HDL2 (d = 1.08--1.125 g/ml) and HDL3 (d = 1.125--1.195 g/ml) that differ in lipid-to-protein ratio was compared by polyacrylamide gel electrophoresis and isoelectric focusing of the apolipoproteins and peptide fragments and by quantitation of the various carboxyl-terminal groups formed. Gel filtration of the proteolyzed lipoproteins on Sephadex G-150 column indicated that more than 90% of the apolipoproteins and peptides remain associated with lipoprotein complexes. Proteolysis of lipoproteins occurred more slowly and with less fragmentation of the lipoproteins and apolipoproteins than proteolysis of thelipid-free apolipoproteins or the proteolysis of lipoproteins by soluble proteases reported by other investigators. The difference in lipid content of HDL2 and HDL3 made little difference in their proteolysis. Proteolysis of the lipoproteins by agarose-trypsin was more rapid at 37 degrees C than at 22 degrees C, but the proteolytic products were similar and differed from the products from the lipid free proteins. Peptide fragments from lipoproteins were larger than those from lipid-free proteins, which suggests masking of potentially cleavable groups by lipid. The amounts (mol/g protein) of new carboxyl-terminal tyrosine and phenylalanine released by agarose -chymotrypsin were much greater from the lipid-free proteins, but about 3/4 of the tryptophan residues were inacessible in both lipoproteins and lipid-free proteins. In agarose-trypsin digestion, lysine residues were slightly more masked than arginine in the absence of lipids and much more so in the lipoproteins. However, in the lipoproteins apoA-II, which contains lysine but no arginine, was cleaved more rapidly and extensively by agarose-trypsin than apoA-I.

Cellular hypersensitivity of gp55 of RIII-murine mammary tumor virus and gp55-like protein of human breast cancers

Previous studies suggested that immunogenic breast cancer tissues contained a component(s) that is antigenically similar to some component of murine mammary tumor virus (MuMTV) and resembles the glycoprotein, M.W. 55,000 (gp55), of RIII-MuMTV in molecular weight and charge density. This investigation measured in vitro cellular hypersensitivity responses of breast cancer patients to RIII mouse milk, purified RIII-gp55, C3H-MuMTV, autologous and homologous breast cancer tissues, gp50 of A-MuMTV, and preparations of Rauscher leukemia virus and Mason-Pfizer monkey virus. Particular attention was paid to cross-reactivity between gp55 and the other targets. The data indicate that responsiveness to C3H-MuMTV and RIII milk are linearly correlated with responsiveness to gp55. A preferential relationship was demonstrable between responses to gp55 and to those breast cancer tissues containing a gp55-like protein component (S-p50). The critical role of a gp55-like protein as the antigen responded to by breast cancer patients' in leukocytes was also suggested by the ability of anti-gp55 antiserum to decrease leukocyte responsiveness to RIII-gp55, C3H-MuMTV, and breast cancer tissues. In vitro cellular hypersensitivity against RIII-gp55 was preferentially found in prognostically favorable cases with immunogenic lesions. Further studies are needed to test the possibility that gp55 might be of value in the immunodiagnosis of early breast cancer, the monitoring of prognostically significant cellular hypersensitivity, and the induction of such hypersensitivity (immunoprophylaxis).

Prognostically significant protein components of human breast cancer tissues

Cryostat sections of clinicopathologically characterized breast cancer tissues were eluted with phosphate-buffered 0.9% sodium chloride solution, pH 7.2. The proteins were then characterized by polyacrylamide gel electrophoresis with and without prior treatment with sodium dodecyl sulfate. Approximately 65% of the brease cancer tissue eluates contained a prominent protein fraction with a molecular weight of 47,000 to 55,000 (p50). No such component was found in 15 of 17 eluates of benign breast tissue. Charge density studies disclosed that the p50 component included three populations of proteins that could be characterized according to the migration relative to gp55 derived from RIII murine mammary tumor virus, namely, fast (F-p50), intermediate (I-p50), and slow (S-p50). Prognostically favorable pathological characteristics, i.e., stage, nuclear grade, and lymphoreticuloendothelial responses, were proportionately most frequently found among S-p50 bbreast cancers and were least frequently found among F-p50 breast cancers. It appears that the S-p50 component acts in vivo as a prognostically significant immunogen. Further knowledge of the relationship between protein characteristics and clinicopathological features of human breast cancers would contribute to our understanding of mammary carcinogenesis and biological behavior.

Biological considerations of tumor-specific and virus-associated antigens of human breast cancers

In vivo and in vitro studies bearing on tumor-specific and viral-associated antigenicity of human breast carcinomas were reviewed with particular attention to the following clinical considerations: (a) breast carcinomas arise in a nonrandom fashion; (b) in situ carcinomas precede invasive breast carcinomas; (c) invasive breast carcinomas behave in a heterogeneous fashion. Microscopically demonstrable lymphoreticuloendothelial responses, skin window tests, and leukocyte migration tests all indicate that tumor-specific antigenicity develops in assoication with the early phases of mammary carcinogenesis. Such antigenicity is maximally expressed in in situ carcinomas without associated invasive breast cancer and minimally in invasive breast cancers with metastases. Immunogenic breast cancer tissues commonly contain a protein component the antigenic and physicochemical properties of which are similar to those of a protein component of murine mammary tumor virus. Advances in our understanding and control of human mammary carcinogenesis and biological behavior are dependent on the clinicopathological characterization of individual patients and their breast tissues as well as on the analytical procedures used.

Rabbits as a model for the study of hyperlipoproteinemia and atherosclerosis

Lipoproteins of normal and cholesteremic plasma were compared in New Zealand White (hyperresponder) and Dutch Belt (hyporesponder) rabbits. Three major differences were observed between the strains: (1) New Zealand White rabbits developed much higher plasma levels of very low, intermediate, and low density lipoproteins after cholesterol feeding; (2) Dutch Belt rabbits, normal and cholesteremic, had higher ratios of the more dense high density lipoproteins HDL3 (d 1.125-1.20 g/ml) to the less dense HDL2 (d 1.081-1.125 g/ml); (3) cholesteremic Dutch Belt rabbits had higher plasma levels of the more dense HDL3 subfraction than did cholesteremic New Zealand White rabbits. Cholesteremic very low density lipoproteins of both strains are large particles of beta electrophoretic mobility that are rich in cholesteryl esters and an arginine-rich apolipoprotein(s). The intermediate and low density lipoprotein fractions were similarly altered in composition, although the proportion of arginine-rich protein to total protein was ledd than in the very low density fraction. Although the high density lipoproteins were greatly decreased in concentration in cholesteremic plasma, no major changes in their apolipoproteins were seen in either strain of rabbits. The major high density apolipoprotein of rabbits occurs in two electrophoretically separable forms and is similar to human apo A-I. Six minor apolipoproteins were isolated from the high density lipoproteins; some of these occur also in other density fractions.

Prognostically favorable immunogens of human breast cancer tissue: antigenic similarity to murine mammary tumor virus

A leukocyte migration procedure was utilized to test cellular hypersensitivity of breast cancer patients' leukocytes to autologous and homologous breast cancer tissues and to murine milk containing murine mammary tumor virus (MuMTV). The in vitro responsiveness of the leukocytes and the antigenicity of breast cancer tissues were compared with in vivo prognostically favorable lymphoreticuloendothelial (L-RE) responses seen microscopically at the time of mastectomy and with the results of skin window tests of cellular hypersensitivity. The data suggest that immunogens appear in the in situ phase of the disease and provoke prognostically favorable L-RE responses. These immunogens possess antigenic similarity to some component(s) of MuMTV. Progression of the disease is associated with or preceded by a loss of tissue immunogenicity and/or diminished specific cellular hypersensitivity. The findings are pertinent to investigations of human mammary carcinogenesis and immunoprophylaxis.

Role of specific glycopeptides of human serum lipoproteins in the activation of lipoprotein lipase

Lipoprotein lipase forms an enzyme-substrate complex with fat emulsions in the presence of serum lipoproteins. Lipoproteins of very low density and high density have this property, but the former are much more active per unit weight of protein. In this investigation, the activity, expressed as quantity giving half-maximal rate of production of free fatty acids, of specific glycopeptides isolated from very low density and high density lipoproteins was tested in an incubation mixture containing lipoprotein lipase from cows' milk and 1.8 mg triglyceride per ml. The two major polypeptides of high density lipoproteins were virtually inactive in amounts up to 100 µg per ml. Activity of the unfractionated apoproteins of very low density lipoprotein was similar to that of the native lipoprotein (about 4 µg/ml). Two of its polypeptides were active: one with carboxyl-terminal glutamic acid at 0.45 to 0.60µg/ml and one with carboxyl-terminal alanine at 1.8.2.8 µg/ml. Some preparations of the latter peptide were less active and inhibited at high levels. Three other glycopeptides from very low density lipoprotein were inactive. Low density lipoprotein from subjects with primary biliary cirrhosis and a lipoprotein of density 1.04 to 1.06 from a subject with specific elevation of this fraction, both containing the active glycopeptides, had considerable activity (5 to 11 µg/ml). These studies indicate that specific glycopeptides are required for the action of lipoprotein lipase on emulsified triglycerides and suggest that they are important components of the mechanism for extra-hepatic utilization of plasma triglycerides.