Primary rhabdomyosarcoma of the alimentary tract is extremely rare, only 11 cases have been reported in the literature. Long-term survival in adults may be possible if the tumor is detected at an early stage even though it is asymptomatic. This highly malignant tumor can be treated by surgical excision, chemotherapy, and irradiation. A 12th case--of stage 1, pararectal, rhabdomyosarcoma--is reported.

Aged↗

PubMedDate not supplied

Associative memory model with temporal spike coding and active dendrite.

We propose a neuron model whose internal state is integrated on a two dimensional phase space composed of time and dendritic space. Here, the postsynaptic potential is given as a curved surface on the phase space. Using the proposed neuron model, we introduce a continuous-time associative memory model with spike propagation delay and multiple synaptic sites on the dendrite. We show by numerical simulation that the memory capacity is doubled due to the effects of temporal spike coding and active dendrite compared to the sparse coding associative memory model.

Action Potentials↗

PubMedDate not supplied

Chaotic stimulus dependent long-term potentiation in the hippocampal CA1 area.

In our previous report [Tsukada, M., Aihara, T., Saito, H., Kato, H., 1996. Neural Netw. 9, 1357-1365], the temporal pattern sensitivity of long-term potentiation (LTP) in hippocampal CA1 neurons was estimated by using Markov chain stimuli (MS) with different values of the serial correlation coefficient rho1 between successive interstimulus-intervals. In this paper, the effect of chaotic stimuli (CS) on induction of LTP in the hippocampal CA1 area was investigated in comparison with that of MS and periodic pattern stimuli (PS). The CS were produced by a modified Bernoulli map, so that interstimulus sequences with various values of rho1 can be generated by changing the parameter B. These stimuli had an identical first order statistics (mean interstimulus-interval), but their higher order statistics such as the serial correlation coefficients were different. The LTP induced by CS at B = 2 was significantly larger in magnitude than that of PS and MS, and also depended on the initial value of CS at B = 2 and 3. These results suggest that chaotic signals play an important role for memory coding in the hippocampal CA1 network.

Hippocampus↗

PubMedDate not supplied

Hyperreactivity of contractile response in gastric fundus smooth muscle from rats with diabetes induced by streptozotocin.

To understand the effects of diabetes on functions of gastric fundus smooth muscle and the underlying mechanisms, we examined the responses to acetylcholine and KCl in gastric fundus of rats with diabetes (3, 6, 12 weeks) induced by streptozotocin (60 mg/kg, i.v.). The contractile responses to the two agonists increased significantly in gastric fundus preparations isolated 6 and 12 weeks after the onset of diabetes, compared to those in tissues from control rats. Influx of Ca2+, induced by 10(-5) M acetylcholine and 60 mM KCl, increased significantly in gastric fundus isolated 6 weeks after the onset of diabetes. Insulin treatment from 3 to 6 weeks after the onset of diabetes restored the responsiveness of gastric fundus to agonists to control levels. The results indicate that changes of both receptor-operated and voltage-dependent Ca2+ channels contribute to hyperreactivity of contractile responses in gastric fundus of diabetic rats.

Acetylcholine↗

PubMedDate not supplied

Doxazosin improves insulin sensitivity in hypertensive patients.

Insulin sensitivity in terms of glucose disposal rate was measured by the hyperinsulinemic/euglycemic clamp technique in 10 hypertensive patients and 7 normotensive control subjects before and after 12 weeks of doxazosin therapy. Supine blood pressure fell significantly, from 150/98 mmHg before treatment to 136/90 mmHg after treatment (systolic P < 0.001/diastolic P < 0.01). The average dose of doxazosin at the end of the study was 3.3 +/- 0.4 mg/day. The glucose disposal rate during the last 30 minutes of the glucose clamp procedure was significantly increased, from 5.8 +/- 0.7 mg/kg/min before to 7.8 +/- 0.7 mg/kg/min after treatment (P < 0.02). Insulin sensitivity was 8.7 +/- 0.4 mg/kg/min in the normotensive subjects, which represented a significant difference when compared with that of the hypertensive subjects before treatment (P < 0.01). Steady-state serum insulin concentrations, as measured during the glucose clamp procedure, were 172 +/- 10.4 microU/ml before and 176 +/- 13.5 microU/ml after doxazosin treatment; these levels were significantly higher than the 137 +/- 7.0 microU/ml reading obtained in the normotensive subjects (P < 0.05). Study results show that hypertensive patients tend to be insulin resistant and that treatment with doxazosin improves insulin sensitivity.

Adult↗

PubMedDate not supplied

A clinicopathological study of malignant glioma done after local administration of chemotherapeutic agents.

Light and electron microscopic studies on tumor tissue from 5 autopsied and 7 rebiopsied patients with malignant glioma after receiving intratumor administration of anti-neoplastic agents were made. Four patients were correlated with their serial MRI. After craniotomy 0.5 mg of adriamycin was administered using an Ommaya reservoir into the tumor bed. Light microscopy of the recurrent tumor and adjacent necrotic tissue revealed massive coagulation necrosis which was aspirated into the tip of the Ommaya tube. Around the massive coagulation necrosis and cystic cavity, abundant reactive collagenous tissues, gliomesenchymal tissue, infiltrating lymphocytes, and a small amount of foreign body giant cells were found concomitantly with organized necrotic tissue. The electron microscopic study of the above mentioned tissue showed deposits of lipofuscin, lipid droplets, lysosomes in the tissue as well as abundant disintegrated myelin figures and fibrous strands. Furthermore, marked histological necrosis was found mainly at the tip of the Ommaya tube. These morphological findings corresponded to the high signal intensity areas on the gadolinium-enhanced T1-weighted MRI. These facts may indicate that the antineoplastic agents administered directly to a tumor per se cause morphological alternations. Moreover, these facts may suggest a therapeutic effect in the residual tumor cells which would be facilitated by formation of coagulation necrosis and collagenous tissue.

Adult↗