Rupture of posterior tibial tendon: CT and MR imaging with surgical correlation

Computed tomography (CT) and magnetic resonance (MR) imaging were performed in 32 cases of clinically suspected chronic tears of the posterior tibial tendon. Surgery was performed in 22 patients (69%). Each case was classified radiographically and surgically as normal or a type 1, type 2, or type 3 rupture. The sensitivity and specificity of CT were 90% and 100%, respectively, while those of MR imaging were 95% and 100%. The accuracy in detecting ruptures was 91% for CT and 96% for MR imaging. The overall accuracy, which reflected the percentage of cases correctly diagnosed as well as those correctly classified, was 59% for CT and 73% for MR imaging. Although the differences between the CT and MR imaging parameters were not statistically significant (possibly due to the small population), the results suggest that MR imaging is the method of choice for detecting ruptures of the posterior tibial tendon. MR imaging provided greater definition of tendon outline, vertical splits, synovial fluid, edema, and degenerated tissue. CT was superior to MR imaging in showing associated bone abnormalities such as periostitis, subtalar osteoarthritis, and subtalar dislocation.

Rational re-design of the substrate binding site of flavocytochrome P450 BM3

Bacillus megaterium P450 BM3 is a fatty acid hydroxylase with selectivity for long chain substrates (C(12)-C(20)). Binding or activity with substrates of chain length <C(12) has not been reported. Rational mutagenesis was used to re-design the enzyme to encourage binding of short chain fatty acids (C(4)-C(10)). We show that wild-type P450 BM3 has activity and weak affinity for substrates as short as butyrate (C(4)). However, turnover/binding of short chain substrates is dramatically increased by introducing a novel substrate carboxylate binding site close to the heme. Mutant L181K shows catalytic efficiency (k(cat)/K(M)) increased >13-fold with butyrate, while the L75T/L181K double mutant has k(cat)/K(M) increased >15-fold with hexanoate and binding (K(d)) improved >28-fold for butyrate. Removing the arginine 47/lysine 51 carboxylate binding motif at the mouth of the active site disfavours binding of all fatty acids, indicating its importance in the initial recognition of substrates.

Normal anatomy and pathologic conditions of ankle tendons: current imaging techniques

Radiologic assessment of tendon injuries requires familiarity with normal anatomy and the capabilities of available imaging modalities. Tenography, less commonly used nowadays, does not allow direct visualization of tendons, so that partial ruptures and longitudinal splits may go undetected. Ultrasonography can depict tenosynovitis, tendinitis, and complete tendon rupture of the Achilles tendon, but the other tendons are difficult to visualize with this technique. Magnetic resonance (MR) imaging is superior to computed tomography (CT) in the depiction of tenosynovitis and peritendinitis, tendinitis, tendon rupture, and tendon dislocation and subluxation. CT can demonstrate these abnormalities, but accompanying scar tissue or edema, early changes of tendon degeneration, and small amounts of inflammatory fluid are difficult to differentiate with this technique. CT is superior for demonstrating calcifications, convex retromalleolar groove, bone fragments, or spurs that complicate tendon dislocation and rupture. Although the authors prefer MR imaging, they caution that all of the modalities are not always specific and that differentiation between closely related processes such as tendinitis and early tendon rupture is difficult.

Magnetic resonance imaging of anomalous leg muscles: accessory soleus, peroneus quartus and the flexor digitorum longus accessorius

Since the availability of magnetic resonance imaging (MRI), the suspected diagnosis of an accessory muscle of the lower extremity can now be confirmed without the need for invasive procedures. The accessory soleus, peroneus quartus, and flexor digitorum longus accessorius are anomalous muscles of the lower extremity that can be diagnosed by MRI. These accessory muscles are probably more common than once thought and can now be easily distinguished from other space occupying lesions that can occur around the ankle. MRI of these anomalous muscles enables one to make a definitive diagnosis without a biopsy. In those symptomatic patients, the origins and insertions of these accessory muscles can be accurately evaluated by MRI prior to any anticipated surgical intervention.

MR imaging of the elbow: normal variant and potential diagnostic pitfalls of the trochlear groove and cubital tunnel

The proximal portion of the ulna includes the olecranon and the coracoid process, which together form the trochlear groove that articulates with the distal humerus. The groove is constricted at the junction of the olecranon and the coracoid process. A thin, transverse, nonarticular ridge intersects the groove at this junction. Both the constriction of the groove and the nonarticular ridge may simulate disease on MR imaging of the elbow.

MR imaging of the ankle: normal variants

Thirty asymptomatic ankles were studied with high-resolution surface coil magnetic resonance (MR) imaging to identify normal structures. Several normal variants were demonstrated, including (a) Cortical irregularity of the posterior tibiotalar joint (should not be mistaken for osteonecrosis) in 27 of 30 cases; (b) normal posterior talofibular ligament with irregular and frayed superior edge simulating a tear in 13 of 30 cases; (c) normal navicular insertion of the posterior tibial tendon with heterogeneous signal intensity in 14 of 30 cases; (d) deltoid ligament inhomogeneity in seven of ten cases; and (e) fluid in the shared peroneal tendons sheath (may be confused with a longitudinal tendon tear) in three of 30 cases. Ankle imaging with the use of MR is still a relatively new procedure. Further investigation is needed to better define normal anatomy and normal variants.

Catecholamine distribution in feline hypothalamus

Catecholamine distribution was examined in cat hypothalamus using the histochemical fluorescence technique of Falck and Hillarp. The heaviest accumulations of catecholamine-containing varicosities were seen within the: anterior periventricular nucleus; dorsal hypothalamic area; bed nucleus of the inferior thalamic peduncle; doral component of the paraventricular nucleus; dorsomedial nucleus; infundibular nucleus; bed nucleus of the stria terminalis-medial division; and supraoptic nucelus. Catecholaminergic perikarya were observed within periventricular, dorsal, and caudal hypothalamic areas as well as within the supramamillary nucleus and caudal diencephalon. Catecholamine distribution in cat hypothalamus possesses both similarities and dissimilarities in relation to distributions reported in other mammals.

MR imaging of dislocation of the posterior tibial tendon

OBJECTIVE

The purpose of this article is to describe the MR imaging appearance of seven cases of posterior tibial tendon dislocation and subluxation.

CONCLUSION

Posterior tibial tendon dislocation is a rare but important entity usually related to a previous traumatic event. The clinical diagnosis is often missed because of its rarity. MR imaging provides important clues to the diagnosis and preoperative evaluation of this condition.

Analysis of indications for surgical closure of subarterial ventricular septal defect without associated aortic cusp prolapse and aortic regurgitation

Subarterial ventricular septal defect (VSD) is relatively common in Orientals. We reviewed the outcome of 214 patients (137 males) who were followed for 8.6 +/- 5.2 years (range 0.1 to 24.3) and addressed the issue regarding the necessity and optimum timing of closing subarterial defects before development of aortic valve deformities. Demographic data, transthoracic and transesophageal echocardiographic findings, cardiac catheterization results, and operative findings were reviewed. Kaplan-Meier actuarial analysis was performed to assess the development of aortic valve complications over time. Seventy-five patients with heart failure and pulmonary hypertension underwent surgical closure of VSD at the age of 2.4 +/- 2.9 years. No patient had aortic cusp prolapse before operation and none developed aortic cusp prolapse or aortic regurgitation (AR) on follow-up. In contrast, of the 139 asymptomatic patients managed conservatively, 102 (73%) developed aortic cusp prolapse, 78% of whom (80 of 102) developed AR. The prevalence of aortic cusp prolapse and AR at 1, 5, 10, and 15 years old was 8%, 30%, 64%, and 83%, and 3%, 24%, 45%, and 64%, respectively. Significant prolapse or AR prompted surgical closure of VSD with (n = 22) or without (n = 26) valvoplasty in 48 of 102 patients (47%). The size of the VSD was significantly larger in patients with heart failure (9.6 +/- 3.3 mm) or aortic cusp prolapse (11.7 +/- 4.1 mm) compared with those without heart failure (4.5 +/- 1.4 mm, p <0.001). All patients with aortic cusp prolapse and all but 1 with heart failure had a defect size of > or =5 mm. In conclusion, subarterial VSD of > or =5 mm should be closed as early as possible to prevent development of aortic cusp prolapse and AR. Asymptomatic patients with small defects <5 mm could be managed conservatively.

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.

Surgical validation and implications for transcatheter closure of quantitative echocardiographic evaluation of atrial septal defect

Accurate evaluation of secundum atrial septal defect (ASD) is important for the success of transcatheter closure. The purpose of this study was (1) to describe a quantitative evaluation by transthoracic (TTE) and transesophageal (TEE) echocardiography of the various morphologic features of ASD that might be important for patient selection for transcatheter closure, and (2) to assess the reliability of these 2 methods by surgical findings. Preoperative TTE and TEE were used to evaluate the ASD of 27 children undergoing surgical closure. Measurements included the diameters of ASD and the atrial septal lengths in the transverse and longitudinal axis, and the width of the superior, inferior, anteroinferior, and posterior septal margins. The shape and location of the ASD and the adequacy of the septal margins for anchoring occluding devices were determined. Echocardiographic data were compared with corresponding surgical measurements. No significant difference occurred in the means of all the parameters measured with the 3 methods, except for the transverse ASD diameter (p <0.05). Good agreement occurred between TTE and TEE and surgical data, except for the transverse ASD diameter, transverse atrial septal length, and the posterior septal margin on TTE. Intraclass correlations between TTE and TEE and surgical measurements of all parameters were good, except for the transverse ASD diameter. The accuracy in determining shape and location of the ASD by TTE and TEE were 100%, whereas that for determining the adequacy of septal margins was 98% and 97%, respectively. In conclusion, TTE and TEE are reliable methods for quantitative evaluation of ASD.

Bladder pheochromocytoma: evaluation with magnetic resonance imaging

A 17-year-old black woman with a large vesical pheochromocytoma was managed successfully by hemicystectomy and ureteroneocystotomy. Preoperatively, in addition to the routine diagnostic evaluation, magnetic resonance imaging was performed. Magnetic resonance imaging proved to be an extremely useful modality to assess the integrity of the bladder wall and extent of extravesical involvement.

Transcatheter closure of persistent arterial ducts with different types of coils

BACKGROUND

Different types of coils have been designed for transcatheter closure of persistent arterial ducts. We compared the efficacy and safety of three types of coils: Gianturco coils (Cook), Cook detachable coils (Cook), and Duct Occlud devices (pfm).

METHODS

Sixty-three patients underwent coil occlusion of arterial ducts between April 1995 and July 2000. The mean age and weight were 4.8+/-3.4 years and 16.5+/-7.6 kg, respectively. The results and complications of ductal occlusion among the three types of coils were compared. Kaplan-Meier analysis was used to assess reduction in the prevalence of residual shunt with time, and multiple regression analysis was performed to identify predictors of complete occlusion.

RESULTS

Coil occlusion of persistent arterial ducts that measured 2. 2 +/- 0.8 mm was feasible in 90% (57/63) of patients. Gianturco coils were used in 29, Duct Occlud devices in 16, and Cook detachable coils in 12 patients. The prevalence of residual shunt at 24 hours, 6 months, 12 months, and 24 months was 42%, 20%, 18%, and 14%, respectively. The reduction in prevalence of residual shunt with time tended to be greater when Gianturco coils were used (P =. 067). Logistic regression identified the use of Gianturco coils to be a significant predictor of complete ductal occlusion on follow-up (P =.04). Pull-through of coils occurred in 4.8% (3/63) and coil embolization in 6.3% (4/63). There was no association between the type of coil and the risk of embolization (P = 1.00).

CONCLUSIONS

Transcatheter occlusion of small persistent arterial ducts with coils is safe and effective. There is no advantage of detachable coils (Cook detachable coils and Duct Occlud devices) over nondetachable Gianturco coils in reducing the risk of embolization. Our findings are in favor of the inexpensive, but more effective, Gianturco coils for occluding small arterial ducts of 3 mm or less.

Future research needs in policy, prevention, and treatment for drug abuse problems

This paper outlines major research issues for the areas of illicit drug use. Research questions are posed for the following areas: (1) epidemiology and etiology; (2) social policy development; (3) prevention; and (4) treatment.

Tl-201 chloride SPECT imaging of hepatocellular carcinoma

PURPOSE

Tl-201 chloride has been used to image viable tumors in various sites of the body. There has been limited use of Tl-201 below the diaphragm because of normal uptake in the liver, spleen, kidneys, and intestines. The use of sequential Tl-201 and Tc-99m sulfur colloid in the detection and characterization of suspected hepatocellular carcinoma (HCC) was prospectively evaluated.

METHODS

Four patients with indeterminate liver nodules on radiologic imaging studies were studied with sequential Tl-201 and sulfur colloid liver scans on a triple-headed gamma camera with planar and SPECT acquisition. All patients had subsequent pathologic correlation.

RESULTS

There were three focal nodular HCC lesions and one case of multicentric HCC, size varying between 1.9 cm and greater than 4.0 cm (multicentric HCC). In all lesions, Tl-201 SPECT images showed abnormal increased uptake at sites of HCC, which corresponded to areas of photopenia on sulfur colloid. Computed tomography detected a lesion in two of four patients, whereas US was positive in all patients. However, US was specific for tumor in only one patient and CT was not specific in any patient.

CONCLUSION

We believe that in patients with suspected HCC, Tl-201 SPECT imaging will have an important role in the detection and characterization of HCC, especially in the cirrhotic patient. Planar Tl-201 hepatic images will usually be normal, except in large lesions, and high-resolution SPECT technique is essential in successful liver tumor imaging.

Expression profile of senescence-associated beta-galactosidase and activation of telomerase in human ovarian surface epithelial cells undergoing immortalization

Senescence is a specific physiological stage of cells characterized by long population doubling time. It accounts for the inability of normal somatic cells to undergo indefinite cell division. As the number of population doublings increase, cell cycle regulatory mechanisms come into play and signal cells to exit the cell cycle and become senescent. Senescence has been implicated in the aging process and may function as a tumor suppressor mechanism in human cells. The ability to measure the degree of cellular senescence is important in understanding the biological processes regulating cell aging and immortalization. Senescent cells exhibit an enzyme termed senescence-associated histochemical staining. Cells immortalized by viral oncogenes often enter a stage of crisis at the early phase of immortalization. The cells at crisis have a long population doubling time. Cells at the crisis stage resemble senescent cells and the expression of SA- beta-Gal may be used to monitor the process of immortalization. In this study the expression profile of SA-beta-Gal was examined in human ovarian surface epithelial cells (HOSE 6-3) undergoing immortalization by the human papilloma viral oncogene E6 and E7 (HPV E6 and E7). Our results showed a low percentage (12.0%) of HOSE 6-3 cells expressing SA-beta-Gal activity at the pre-crisis stage. The percentage of HOSE 6-3 cells expressing SA-beta-Gal activity was highest (39.2%) at the crisis stage. When HOSE 6-3 cells achieved immortalized status there was a sharp decrease in cells (1. 3%) expressing SA-beta-Gal activity. In addition, an inverse relationship between the expression of SA-beta-Gal activity and telomerase activity was noted in cells undergoing immortalization. The results confirm that the SA-beta-Gal enzyme is a good marker for monitoring the population of cells undergoing senescence at different stages of immortalization and that telomerase activation is a characteristic feature of post-crisis cells.