Middle segmental pancreatectomy: a safe and organ-preserving option for benign and low-grade malignant lesions.

AIM: To study the feasibility and safety of middle segmental pancreatectomy (MSP) compared with pancreaticoduodenectomy (PD) and extended distal pancreatectomy (EDP). METHODS: We studied retrospectively 36 cases that underwent MSP, 44 patients who underwent PD, and 26 who underwent EDP with benign or low-grade malignant lesions in the mid-portion of the pancreas, between April 2003 and December 2009 in Ruijin Hospital. The perioperative outcomes and long-term outcomes of MSP were compared with those of EDP and PD. Perioperative outcomes included operative time, intraoperative hemorrhage, transfusion, pancreatic fistula, intra-abdominal abscess/infection, postoperative bleeding, reoperation, mortality, and postoperative hospital time. Long-term outcomes, including tumor recurrence, new-onset diabetes mellitus (DM), and pancreatic exocrine insufficiency, were evaluated. RESULTS: Intraoperative hemorrhage was 316.1 ± 309.6, 852.2 ± 877.8 and 526.9 ± 414.5 mL for the MSP, PD and EDP groups, respectively (P < 0.05). The mean postoperative daily fasting blood glucose level was significantly lower in the MSP group than in the EDP group (6.3 ± 1.5 mmol/L vs 7.3 ± 1.5 mmol/L, P < 0.05). The rate of pancreatic fistula was higher in the MSP group than in the PD group (42% vs 20.5%, P = 0.039), all of the fistulas after MSP corresponded to grade A (9/15) or B (6/15) and were sealed following conservative treatment. There was no significant difference in the mean postoperative hospital stay between the MSP group and the other two groups. After a mean follow-up of 44 mo, no tumor recurrences were found, only one patient (2.8%) in the MSP group vs five (21.7%) in the EDP group developed new-onset insulin-dependent DM postoperatively (P = 0.029). Moreover, significantly fewer patients in the MSP group than in the PD (0% vs 33.3%, P < 0.001) and EDP (0% vs 21.7%, P = 0.007) required enzyme substitution. CONCLUSION: MSP is a safe and organ-preserving option for benign or low-grade malignant lesions in the neck and proximal body of the pancreas.

Congenital choledochal cysts in adults: twenty-five-year experience.

BACKGROUND: Choledochal cyst is rare in western countries. The relatively high incidence of coexistent hepatobiliary disease increases the difficulty of the surgical management of choledochal cyst. Here we analyze the diagnosis and treatment of congenital bile duct cyst in 122 Chinese adults. METHODS: The clinical data of 122 patients with congenital choledochal cysts admitted from 1981 to 2006 were analyzed. RESULTS: Clinical symptoms in most cases were nonspecific, resulting in delayed diagnosis. Sixty-one patients (50%) had coexistent pancreatobiliary disease. Among the 122 patients, 119 patients underwent ultrasonic examination; ERCP/MRCP was performed in 63 cases and CT in 102 cases. Abnormal pancreatobiliary duct junction was found in 48 patients. Sixteen patients had malignant lesions in the bile duct, arising in 11 of them from incomplete choledochal cyst that underwent various operations including cystenterostomy or cystojejunostomy. There was significant difference between the patients who underwent incomplete cyst resection and complete cyst resection in malignancy rate of bile duct (Chi square test, P = 0.000; odds ratio, 7.800; 95% confidence interval, 2.450 to 24.836). CONCLUSIONS: ERCP, CT and MRCP had proved their great values in the classification of the disease. Cyst excision with Roux-en-Y hepaticojejunostomy is recommended as the treatment of choice for patients with type I or type IV cysts. For type V cyst (Caroli's disease) with recurrent cholangitis, liver transplantation should be considered.

[Changes in electrophysiological and morphological properties of neurons during the development of the visual cortex in the rat].

To investigate the intracellular mechanism of activity-dependent synapses formation and redistribution, we studied the electrophysiological and morphological characteristics of neurons of the developing visual cortex, and observed the level of synchronism of age and changes in the properties. Whole cell patch-clamp recordings and intracellular biocytin staining were used to record postsynaptic currents (PSCs) from neurons in the visual cortex of Sprague-Dawley rats (postnatal d 4-28). The histological processing was made. There were three types of PSCs in 156 cells: silent response, monosynaptic response and polysynaptic response, during the first developmental month. Before eyes opened the number of the neurons with the silent response (57.3%) was significantly higher than that after the eyes opened (11.9%) (P<0.001). However, the incidence of polysynaptic PSCs increased from 12.4% before eyes opened to 28.9% after eyes opened (P<0.01). During postnatal week 1, all cells were classified as immature. The immature cells had very high input resistances (R(N)>1.0 G Omega), low amplitude (-0.87 mA) and short decay time (-0.98 ms). During postnatal week 4, all cells were mature with lower input resistance (R(N)<310 M Omega), larger amplitude (-66 mA), and longer decay time (-225 ms). From postnatal weeks 1 to 3, the cells had electrophysiological properties that were intermediate between the immature and mature types of cells. With biocytin intracellular staining, five types of neurons were obtained: pyramidal cells, satellite cells, basket cells, neuroglial cells and immature cells. On the basis of their electrophysiological and morphological characteristics, pyramidal cells were classified into three categories: immature, intermediate, and mature cell types. During postnatal week 1, cells were immature with very high input resistance. Morphologically immature cells had short simple dendritic arborizations which incompletely penetrated the layer where the cell body lies. From postnatal weeks 2 to 4, the cells were mature with low input resistance. They were morphologically more complex with dendritic arborizations which completely penetrated the whole layers of the visual cortex. From postnatal weeks 1 to 2, a third, intermediate cell type had electrophysiological properties that were intermediate between the immature and mature cell types. Three distinctive types of pyramidal cells in visual cortex only co-exist during postnatal weeks 1 to 2. Data show that activity-dependent synapes are formed and integrated into local neuronal networks with visual stimulation. In the critical period of visual development, the level of synchronism of age and changes in electrophysiological and morphological properties in the visual cortex is higher than that in the subcortex.

NMDA receptor-mediated currents in rat cerebellar granule and unipolar brush cells.

The properties of N-methyl-D-aspartate (NMDA) receptor-mediated currents at the giant cerebellar mossy-fiber unipolar brush cell (UBC) synapse were compared with those of adjacent granule cells using patch-clamp recording methods in thin slices of rat cerebellar nodulus. In UBCs, NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) decayed as a single exponential whose time constant was independent of membrane potential. The EPSC was reduced in all cells by the NR1/NR2B-selective antagonist ifenprodil, and the Zn(2+) chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) produced a transient potentiation in 50% of cells. In contrast, the NMDA EPSC in granule cells decayed as a double exponential that dramatically switched to a slower rate at positive membrane potentials. The synaptic response in some granule cells also displayed a late second peak at positive potentials, and in others, activation of mossy fibers produced repetitive trains of EPSCs indicating they may be postsynaptic to the UBC network. Single-channel recordings of outside-out somatic patches from UBCs in magnesium-free solution revealed only high-conductance (50 pS) channels whose open time was increased with depolarization, but the opening frequency was decreased to yield a low (p(o) = 0.0298), voltage-independent opening probability. Lowering extracellular calcium (2.5-0.25 mM) had no effects on channel gating, although an increase of single-channel conductance was observed at lower calcium concentrations. Taken together, the data support the notion that the NMDA receptor in UBCs may comprise both NR1/NR2A and NR1/NR2B receptors. Furthermore, the properties of the EPSC in these two classes of feedforward glutamatergic interneurons display fundamental differences that may relate to their roles in synaptic integration.