Tibial press-fit fixation of the hamstring tendons for ACL-reconstruction

Press-fit fixation of patellar tendon bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary to achieve fixation. Up till the present point, there is no biomechanical data available for the tibial press-fit fixation of the hamstring tendons. Hamstring tendons of 21 human cadavers (age: 41.9 ± 13.1 years) were used. A press-fit fixation with looped semitendinosus and gracilis tendons secured by a tape (T) over a bone bridge, or by a baseball-stitched suture (S), was compared with degradable interference screw fixation (I) in 21 porcine tibiae. The constructs were cyclically strained and subsequently loaded to failure. The maximum load to failure, stiffness, and elongation during cyclical loading were measured. The maximum load to failure was highest for the T-fixation at 970 ± 83 N, followed by the I-fixation with 544 ± 109 N, and the S-fixation with 402 ± 78 N (P < 0.03). Stiffness of the constructs averaged 78 ± 13 N/mm for T, 108 ± 18 N/mm for S, and 162 ± 27 N/mm for I (P < 0.03). Elongation during initial cyclical loading was 2.0 ± 0.6 mm for T, 3.3 ± 1.1 mm for S, and 1.4 ± 0.5 mm for I (S inferior to I and T, P<0.05). Elongation between the 20th and 1,500th loading cycle was lower for T (2.2 ± 0.7 mm) compared with I (4.1 ± 2.7 mm) and S (4.8 ± 0.7 mm; P < 0.001). The T-fixation technique exhibited a significantly higher failure load than the S-, and I- techniques. All techniques exhibited larger elongation during initial cyclical loading than is reported in the literature for grafts with bone blocks. Only one technique (T) showed satisfactory elongation behavior during long-term cyclic loading. Interference screw fixation demonstrated significantly higher stiffness. Only one of the investigated techniques (T) seemed to exhibit adequate mechanical properties necessary for early aggressive rehabilitation programs.     

Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake

Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT_2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK _a value leads to ionization of the molecule at blood pH, the pK _a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK _a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK _a cannot be simply explained by the increase in the pK _a-governed proportion of the neutral species.     

The ethics and reality of rationing in medicine

Rationing is the allocation of scarce resources, which in health care necessarily entails withholding potentially beneficial treatments from some individuals. Rationing is unavoidable because need is limitless and resources are not. How rationing occurs is important because it not only affects individual lives but also expresses society's most important values. This article discusses the following topics: (1) the inevitability of rationing of social goods, including medical care; (2) types of rationing; (3) ethical principles and procedures for fair allocation; and (4) whether rationing ICU care to those near the end of life would result in substantial cost savings.     

Histoplasmosis and AIDS co-infection

This report concerns an AIDS patient presenting systemic and cutaneous manifestations of histoplasmosis. A histopathological and mycological examination of the skin lesion confirmed the diagnosis. In AIDS patients histoplasmosis arises mainly when the T-CD4+ cell count is less than 50 cells/mm3. In such cases, histoplasmosis can be severe and if left untreated can lead to death, as occurred with this patient.     

Do you know this syndrome?

Goltz syndrome is a rare genetic disease of X-linked dominant inheritance. It is more common in female patients and, in most cases, results in miscarriage of male fetuses. It has a broad scope of possible clinical manifestations. Its diagnosis consists of the sum of the many clinical, radiological and histopathological findings. The treatment options are genetic counseling, reconstructive surgery and multidisciplinary approach, aiming to improve quality of life and ensure a normal and productive life.     

Microbiological assay for determination of ofloxacin injection.

A simple, sensitive and specific agar diffusion bioassay for the antibacterial ofloxacin was developed using a strain of Micrococcus luteus ATCC 9341 as the test organism, ofloxacin at concentration ranging 12-27 microg ml(-1) could be measured in injection. A prospective validation of the method showed that method was linear (r=0.9994) and precise (CV=1.14). UV spectrophotometric and high performance liquid chromatographic techniques were chosen as a comparison methods for the determination of ofloxacin. The results obtained by three methods were statistically analyzed by analysis of variance (ANOVA) and the results obtained indicate that there is no significant difference among these methods.     

Direct genetic analysis of single disseminated cancer cells for prediction of outcome and therapy selection in esophageal cancer

The increasing use of primary tumors as surrogate markers for prognosis and therapeutic decisions neglects evolutionary aspects of cancer progression. To address this problem, we studied the precursor cells of metastases directly for the identification of prognostic and therapeutic markers and prospectively analyzed single disseminated cancer cells from lymph nodes and bone marrow of 107 consecutive esophageal cancer patients. Whole-genome screening revealed that primary tumors and lymphatically and hematogenously disseminated cancer cells diverged for most genetic aberrations. However, we identified chromosome 17q12-21, the region comprising HER2, as the most frequent gain in disseminated tumor cells that were isolated from both ectopic sites. Survival analysis demonstrated that HER2 gain in a single disseminated tumor cell but not in primary tumors conferred high risk for early death.