Morphological characteristics of the gyrus dentatus in some animal species and in man

Comparative anatomical investigations have been carried out on the gyrus dentatus of rat, fox, cattle, domestic pig, monkey (Cercopithecus sabeus) and man. After removal of the brain stem and scaling off the brain substance from the medial aspect towards the lateral aspect, the gyrus dentatus was preserved and its relation with regard to the hippocampus, the fimbria hippocampi and the gyrus parahippocampalis was studied. A rat's gyrus dentatus occupies a rather wide zone on the medial aspect of the brain. Its surface is almost flat with very poor denticulations, and below the splenium corporis callosi it forms the tuberculum gyri dentati which is wider than the splenium. In the cat somewhat better pronounced denticulations were observed, and the gyrus dentatus was directed from the rostral aspect towards the dorsal and the lateral, and before reaching the splenium corporis callosi it changed its course towards the medial aspect and passed into the tuberculum gyri dentati. The cattle's gyrus dentatus is rather wide and macroscopically without a sharp definition from the hippocampus. Domestic pig's denticulations are better pronounced particularly towards the gyrus parahippocampalis. The gyrus dentatus of the monkey is well retracted into the fissura hippocampi and below the splenium corporis callosi the tuberculum gyri dentati is barely visible. The authors found the most developed gyrus dentatus in man, but here, the tuberculum gyri dentati was missing.     

Giant synovial cyst of knee treated arthroscopically through a cystic portal

Synovial cysts are well-defined fluid filled cysts that can extend for a variable distance outside the joint space. These cysts can sometimes grow to a large size making its treatment challenging especially when associated with intra-articular pathologies.We describe a case of giant synovial cyst arising from the left knee and extending to the medial proximal calf in a 77-year old female who presented with knee joint pain, episodes of locking and calf mass occurring within 2 months of onset. Imaging studies also showed associated medial and lateral meniscal tears with medial compartment and patellofemoral osteoarthritis. The cyst was treated by disrupting the valvular mechanism using a standard posteromedial portal and complete excision of the cyst wall via a posteromedial cystic portal. The meniscal lesions were dealt with through the standard anterior portals. At 25-month follow up there were no signs of recurrence of the cyst clinically or with MRI. The cystic portal technique is effective in treating a giant synovial cyst of the knee even in the presence of meniscal tears and high grade chondral lesions. An erratum to this article can be found at     

MR imaging findings of early bile duct cancer

Purpose

To retrospectively evaluate the MR imaging features of early bile duct cancer and to correlate them with the clinicopathologic findings.

Materials and Methods

This retrospective study was approved by our institutional review board, and informed consent was waived. Seventeen patients with surgically proven early bile duct cancer who had undergone preoperative MR cholangiopancreatography with gadolinium‐enhanced MR imaging, were included in this study. Two, experienced radiologists evaluated the MR images in consensus regarding the following findings: tumor number and morphology; signal intensity of the tumor; sharpness of the outer border of the bile duct wall; enhancement pattern of the tumor; and the presence of enlarged peribiliary lymph nodes. Another radiologist measured the SNR of the tumor and bile duct wall on gadolinium‐enhanced MRI during the dynamic phases to evaluate the tumor enhancement degree.

Results

In all patients, MR imaging demonstrated single or multiple intraluminal bile duct masses showing a sharply defined outer margin. The most common enhancement pattern of the biliary lesions showed heterogeneous amorphous enhancement or heterogeneous enhancement with central, dot‐like structures or vascular structures (76.5%, 13/17 patients). The difference of SNR between bile duct and tumor was greatest in the equilibrium phase (P < 0.05).

Conclusion

MRCP combined with dynamic contrast‐enhanced MRI can be useful for detecting early bile duct cancers. Common MR findings of early bile duct cancer include one or more inhomogeneously enhancing intraductal masses with clear outer margins and preservation of the bile duct wall. J. Magn. Reson. Imaging 2008;28:1466–1475. © 2008 Wiley‐Liss, Inc.     

Analysis of alkaloids in the seeds ofZizyphus jujuba by high performance liquid chromatography

A high performance liquid chromatographic method was developed for the separation and determination of seven alkaloids in “sanjoin” (the seeds ofZizyphus jujuba, Rhamnaceae), a plant with potent sedative activity. A reverse phase system of Lichrosorb RP-Select B column and 0.05 M potassium phosphate buffer (pH=3.5)-acetonitrile with gradient elution was employed. Two known alkaloids, juzirine and lysicamine, were newly isolated fom “sanjoin”.     

Hemodynamic Response To In Situ Latissimus Dorsi Muscle Stimulation: Implications in Dynamic Cardiomyoplasty

A bstract Dynamic cardiomyoplasty (DCM) involves the electrical stimulation of a pedicled latissimus dorsi muscle flap wrapped around the failing ventricle as a means of cardiac assist. To further elucidate a potential neurohumoral mechanism for improvement of cardiac output after myoplasty, we evaluated the hemodynamic effects of in situ stimulation of the latissimus dorsi muscle (in the absence of cardiomyoplasty). In seven mongrel dogs, a nerve cuff electrode (Medtronic 6901) was placed around the left thoracodorsal nerve (TDN). This was attached to a pulse generator (Medtronic, Itrel 7420), delivering a 4.0 volt, 0.19 second on, 0.81 second off, 33 Hz, 210 microsecond pulse width, cyclic bursts similar to that used in DCM. Stroke volume index (SVI) and other hemodynamic parameters as well as plasma norepinephrine (NE) levels were measured at five stages: baseline, stimulator on at 0, 2, and 5 minutes, and stimulator off at 30 minutes after. The animals were then subjected to 4 weeks of rapid pacing at 240 beats/min (Medtronic 8329) to induce heart failure, and as the rapid pacing was discontinued, measurements were repeated as above. After rapid pacing, cardiac function was significantly depressed, and NE was elevated (133 ± 69 versus 500 ± 353 pg/mL, p < 0.05). In the normal hearts, TDN stimulation increased SVI, heart rate, systemic pressure, and NE levels. In heart failure, however, no significant changes in cardiac function and NE levels were noted. In conclusion, our data indicate that in the normal hearts, afferent impulses from TDN stimulation alone may augment cardiac function by means of a neurohumoral effect that is not seen in severe heart failure. The implications of these findings in DCM are discussed.     

Effect of curing method and curing time on the microhardness and wear of pit and fissure sealants.

OBJECTIVE: To evaluate the effects of a light source, polymerization time and storage time on the microhardness and wear of pit and fissure sealants. METHODS: Five commercial pit and fissure sealants (Fissurit F [FF], Teethmate F1 [TF], Apollo Seal [AS], Concise [CC], and Ultraseal XT Plus [US]) were used. Specimens were cured with a conventional visible light curing unit (Curing Light XL 3000) for 10, 20, 30, 40s or with a plasma arc light curing unit (Apollo 95E) for 3, 6, 9, 12s. The specimens were kept dry in light-shielded bottles at 37 degrees C for 1 week, then half of them were thermocycled. The rest of them were stored in distilled water in light-shielded bottles for another 30 days, which were kept in an incubator at 37 degrees C, followed by thermocycling. Microhardness and wear of the specimens were measured. RESULTS: Similar degree of microhardness was achieved with the shorter curing time with the plasma arc light curing unit as with the conventional visible light-curing unit. With conventional visible light curing, the microhardness of the top surface was higher than that of the bottom surface (P<0.05). With plasma arc light curing, the microhardness of the top surface was higher than that of the bottom surface for AS and CC, but for FF, TF and US, the microhardness of the top surface was lower than that of the bottom surface, except in the 3-s curing of US. For FF, AS, CC and US, wear in the 6s curing with plasma arc light was similar to or less than that of the 30s curing with conventional visible light, but for TF, wear of the 9s curing with plasma arc light was similar to that of the 20s curing with conventional visible light. After storage in distilled water for 30 days followed by thermocycling, there was a tendency towards a decrease in microhardness and an increase in wear. There was a significant negative correlation between microhardness and wear (P<0.01). SIGNIFICANCE: The tested curing methods differed significantly in their curing capacity. This study suggested that a plasma arc light curing unit needs shorter curing time than a visible light curing unit to achieve similar mechanical properties of the pit and fissure sealants tested.