Structural insight into the substrate specificity of Bombyx mori β-fructofuranosidase belonging to the glycoside hydrolase family 32

Sucrose-hydrolyzing enzymes are largely divided into β-fructofuranosidase and sucrose α-glucosidase. The domestic silkworm Bombyx mori possesses both enzymes, BmSUC1 and BmSUH, belonging to the glycoside hydrolase family 32 (GH32) and GH13, respectively. BmSUC1 was presumed to be acquired by horizontal gene transfer from bacteria based on phylogenetic analysis and related to tolerance to sugar-mimic alkaloids contained in mulberry latex. Here we investigated the substrate specificity of recombinant BmSUC1 that can hydrolyze not only sucrose but also fructooligosaccharides and fructans, and revealed that the enzyme was competitively inhibited by 1,4-dideoxy-1,4-imino-D-arabinitol, one of the alkaloids. Moreover, the crystal structures of BmSUC1 in apo form and complex with sucrose were determined, and the active site pocket was shallow and suitable for shorter substrates but was related to more relaxed substrate specificity than the strict sucrose α-glucosidase BmSUH. Considering together with the distribution of BmSUC1-orthologous genes in many lepidopterans, our results suggest that BmSUC1 contributes to the digestion of fructooligosaccharides and fructans derived from feed plants.

[A case of Gerstmann-Sträussler-Scheinker disease with severe muscular atrophy and vertical gaze palsy]

Here we report a case of 56-year-old man with Gerstmann-Sträussler-Scheinker disease (GSS). He had gait disturbance, limb and truncal ataxia, dysarthria and dysphagia at the age of 53. When he developed vertical gaze palsy and dystonic posture of the neck, subcortical dementia, progressive supuranuclear palsy was suspected. Thereafter dementia rapidly progessed, and CT scan showed severe atrophy of the brain. Since severe muscular atrophy and fasciculation also appeared, and abnormality in the codon 102 of prion protein gene was found, he was diagnosed to have the classical type of GSS. GSS with vertical gaze palsy has never been reported, and involvement of the lower motor neuron is also very rare. Therefore, the present case is an atypical type of GSS.

[A case of midbrain infarction with acute bilateral cerebellar ataxia]

An 81-year-old man was suffered from acute dysarthria and gait disturbance. Bilateral cerebellar ataxia and ataxic dysarthria were the only neurological findings. MRI images revealed an infarction in the lower and medial part of the midbrain. We consider that bilateral ataxia of the present case was caused by the lesion at the decussation of the superior cerebellar peduncle.

Adrenal rest tumor of the liver: a case report with immunohistochemical investigation of steroidogenesis

A case of adrenal rest tumor arising in the liver of a 62-year-old male with chronic hepatitis type C is reported. The tumor was clinically non-functioning and required distinction from hepatocellular carcinoma. The yellowish-brown tumor measured 25 x 18 x 15 mm and was located in the subcapsular portion of the right hepatic lobe. Histologically, the tumor presented features similar to those of the adrenal cortex and was predominantly composed of pale cells. Electron micrograph revealed lipid droplets and mitochondria with tubulo-vesicular cristae, consistent with the characteristics of steroid-producing cells. Immunohistochemically, the tumor expressed the adrenal 4 binding protein and a number of enzymes involved in the synthesis of adrenocortical steroids. At surgery, the right adrenal gland was present independently from the liver. This hepatic tumor was considered to be an adrenal rest tumor with steroidogenic capability.

[Clinical evaluation of serum 1,5AG levels in patients with liver cirrhosis]

We measured serum 1,5 anhydroglucitol (1,5AG) levels by HPLC in 32 patients with liver cirrhosis, 32 with diabetes mellitus and 61 normal subjects. Serum 1,5AG was significantly lower in patients with diabetes mellitus and liver cirrhosis compared with that in normal subjects. Serum levels of type IV collagen were higher in patients with liver cirrhosis than in those without liver cirrhosis. A negative correlation was observed between serum 1,5AG and type IV collagen in patients with liver cirrhosis (r = -0.37, p < 0.05), but not in patients with diabetes mellitus. These data suggest that serum 1,5AG levels reflect the degree of liver cirrhosis.

Surgery for hepatocellular carcinoma with tumor thrombus in the right atrium

Three cases of tumor thrombus that originated from a hepatocellular carcinoma in the liver and extended into the right atrium are described. All patients had received both resection of the tumor thrombus and lobectomy of the liver either simultaneously or independently within a short interval. Surgical order and extracorporeal circulation system were varied depending on the thrombus extension. Two of the patients died within 4 months of surgery due to different reasons and the other is doing well at 24 months after surgery.

Enlargement of multiple cavernous hemangioma of the liver in association with pregnancy

Four cavernous hemangiomas were found in a 34-year-old woman after the first delivery. All four hemangiomas became enlarged after the second delivery. Due to complaints of symptoms of compression, and to rule out malignancy, surgical intervention was employed. Histologically, the tumors were typical cavernous hemangiomas. Although a relationship between enlargement of hemangiomas and estrogen was suggested, estrogen receptors were not detected in the tumors.

Comparison of doubling times of serum carcinoembryonic antigen produced by various metastatic lesions in recurrent gastric and colorectal carcinomas

The authors measured the serial serum carcinoembryonic antigen (CEA) levels in patients with recurrent gastric or colorectal carcinoma. Among the 45 patients with recurrent gastric carcinomas, those with lung metastases showed the most prolonged CEA doubling time (CEA-DT), followed by those with liver and peritoneal metastases, respectively. Of the 31 patients with recurrent colorectal carcinomas, those with local recurrence showed the most prolonged CEA-DT, followed by those with lung, liver, and peritoneal metastases, respectively. A positive correlation was observed for gastric and colorectal carcinomas between CEA-DT in patients with metastatic lesions and outcome (R = 0.84 and 0.93, respectively). The results of the current study suggest that postoperative measurement of CEA-DT is useful in the determination of region of recurrence of carcinoma, which would permit early surgery and chemotherapy. Measurement of CEA-DT also may be helpful for the accurate determination of prognosis.

Heterogeneity in early and advanced gastric carcinomas by flow cytometric DNA analysis

We investigated 230 systematically sampled fresh specimens from 12 early and 26 advanced gastric cancer patients by DNA flow cytometry for heterogeneity in DNA content. Fifty-eight percent of the 12 early gastric cancers were uniformly diploid and 42% were uniformly aneuploid. Fifty-four percent of advanced cancers were uniformly diploid in superficial layers and 42% were uniformly diploid in deep layers, whereas 46% were uniformly aneuploid in superficial layers, and 50% were uniformly aneuploid and 8% were heterogeneously aneuploid and diploid in deep layers. Both diploid and aneuploid samples were obtained from 15% for advanced cancers, but ploidy heterogeneity did not occur in early cancers. Heterogeneity for DNA index (more than one aneuploid DNA index) occurred in 46% of whole thickness of advanced cancers, in 19% of superficial layers of advanced cancers, and in 8% of early cancers. We concluded that DNA ploidy determination using superficial layer specimens may be reliable in early gastric cancer but must be interpreted with care in advanced cancer.

Evaluation of an oleic acid water-in-oil-in-water-type multiple emulsion as potential drug carrier via the enteral route

A water-in-oil-in-water (W/O/W) emulsion composed of oleic acid was used as a carrier of carboxyfluorescein (CF) via the enteral route, as a model for future drug transport. The absorption of CF in the small intestine of rats given the emulsion (W/O/W group) was compared with the absorption in a group administered CF alone (CF group), and a group administered a mixed micelle of oleic acid and a surface-active agent in CF solution (MM group). Higher amounts of CF were absorbed in the W/O/W and MM groups than in the CF group. At 120 min, the amount of CF remaining in the intestinal tract was smaller in the MM group than in the W/O/W group. In the early period, CF excretion into bile was higher in the MM group than in the W/O/W group, but from 120 to 360 min, CF excretion in the W/O/W group was higher than in the MM group (non-specific). The blood CF level was significantly higher at 240 and 360 min in the W/O/W group than in the other two groups. The highest concentration in lymph was found in the W/O/W group. The W/O/W emulsion was considered superior to the micelles because it maintained a higher blood level of CF over long periods and transferred it to the lymph. This suggests that the W/O/W emulsion is applicable as a drug carrier via the enteral route.

Comparison of flow cytometric DNA content in primary gastric carcinoma and metastases

Nuclear DNA contents were comparatively determined by flow cytometry in primary and metastatic lesions from 112 cases with stomach cancer. Aneuploidy frequency and mean DNA index were higher in lymph node metastatic lesions than in primary lesions, both resected synchronously. In these lymph node metastatic lesions, DNA ploidy patterns did not change in 79% (89/112 cases), and did change in 21% (23/112 cases). Concordance of the DNA index between primary lesions and synchronous liver metastatic lesions was seen in 63% (5/8 cases), but the concordance rate was only 25% (4/16 cases) for primary lesions and metachronous liver metastatic lesions and 0% (0/8) for primary lesions and lung metastases. DNA ploidy changes in metastatic lesions were marked in distal metastatic lesions, or more marked in metachronous metastases than in synchronous ones. The results of the present study suggested the possibility of detecting changes in biological characteristics of metastatic lesions by flow cytometric DNA analysis.

Metastatic mode of gastric carcinoma by flow cytometric and clinicopathologic parameters

We used flow cytometric and conventional clinicopathologic parameters to analyse the metastatic mode of cancer in 113 stomach cancer patients. Liver metastasis was frequent in cases with intestinal-type cancer, cancer located in the distal stomach, positive venous invasion and aneuploid cancer. Lung and pleural metastasis (excluding nodular lung metastasis), however, were frequent in cases with serosal invasion and diploid cancer. Peritoneal metastasis was frequently seen with tumors located in the proximal or whole stomach, diffuse-type cancer and cancer with serosal invasion. All cases developing bone metastasis were positive for lymph node metastasis. DNA ploidy was partially related to the metastatic mode of stomach cancer, but this was not the sole parameter for predicting metastasis. However, prediction may be possible if based on both DNA ploidy and clinicopathologic parameters, suggesting the possibility of the prophylaxis of recurrence by appropriate postoperative adjuvant therapy.

Metastatic mode and DNA ploidy in gastric carcinoma

We studied the amounts of nuclear DNA in gastric cancer metastases histologically and cytochemically by flow cytometry, which was performed retrospectively on paraffin-embedded specimens from 95 patients. At surgery, all cases of aneuploid cancer were positive for lymph node metastases. Liver metastases were frequently seen in aneuploid cancer (63%, P < 0.01), while lung metastases were the most common in diploid cancer (50%, P < 0.05). The incidence of peritoneal metastasis was high in undifferentiated diploid cancer (72%, P < 0.01). Local lymph node recurrence after surgery was more common in aneuploid than in diploid cancer (P < 0.01). The incidence of bone and distant lymph node metastasis was found to be strongly dependent on tissue differentiation. The DNA ploidy pattern is thus considered to be closely linked to lymph node, liver, and lung metastases in gastric cancer.

Relationship between plasminogen activators and stomach carcinoma stage

The antigen levels of plasminogen activators (PAs), tissue-type PA (t-PA) and urokinase-type PA (u-PA), were measured in extracts from 30 gastric carcinomas and corresponding normal gastric mucosa. The t-PA level was significantly higher in normal mucosa than in cancer tissue, while the u-PA level was significantly higher in cancer tissue. The u-PA level increased with increasing tumor stage, and there was a significant difference between early and advanced cancer. The u-PA level also increased with the degree of nodal involvement, and it was higher in undifferentiated tumors than in well-differentiated ones. It was higher in cases with venous invasion, liver metastasis or peritoneal dissemination than in cases without these features.

[An analysis of the cellular DNA contents in lung-metastasized stomach cancers]

A study has been conducted of the cellular DNA contents in the primary and metastatic lesions of 30 cases of lung-metastasized stomach cancers, in which each DNA Index (DI) was calculated and analysed comparatively. As a consequence, the rate of the diploid type in the nodular lung metastases was found to be higher than the rate of the others. Further, the DI's of 22 out of 30 (73%) metastatic lymph nodes corresponded with those of the primary lesions. Four lung metastatic lesions out of five differed from their primary lesions, but all five lesions simulated their metastatic lymph nodes. Thus understanding of the properties of the metastatic lymph nodes, rather than their primary lesions, would seen to be helpful in planning the therapy to combat recurrent cancers.

[A case of rupture of a posterior pancreaticoduodenal artery aneurysm]

A 75 year old man complaining of right upper abdominal pain was admitted to our hospital. He became shocked with hypotension and cold sweat, and immediately underwent operation. Laparotomy revealed massive hemorrhage in the retroperitoneal region, particularly in the right upper space. It was derived from the rupture of the posterior pancreaticoduodenal artery aneurysm. The arterial trunk was ligated above and below the aneurysm and the aneurysmectomy was carried out. The patient recovered and was discharged from the hospital 56 days after operation. There was no other visceral artery aneurysm and the etiology of this aneurysm was unknown. Four cases of pancreaticoduodenal artery aneurysm have been reported in Japan and three of them were operated, but this is the first surgically resected case for the rupture of pancreaticoduodenal artery aneurysm with success.

Progression and regression of atherosclerosis

Relation of the intimal change in aging of various arteries to progression of atherosclerosis and the morphology of regression of atherosclerotic lesion were discussed. The course of regression of experimental atherosclerosis in rabbits and its histological findings were described.

Rhodopsin bleaching signals in essential night blindness

1. The dark-adaptation curves of two subjects with essential night blindness revealed no evidence for functioning rod vision. Cone vision was normal.2. The photopupillomotor dark adaptation, and flash intensity response amplitude curves on one of these subjects confirmed the absence of rod function.3. However, there is the normal amount of rhodopsin in their rods with normal kinetics.4. Cone pigment kinetics are also nearly normal. After a full bleach, log threshold elevation of the foveal cones is linearly related to pigment regeneration. The constant of proportionality is about 3.0 as it is in the normal retina.5. After a full rhodopsin bleach, the contralateral pupil size recovered its full dark value along a curve which followed the regeneration of rhodopsin.6. The results in (5) are identical to those previously found on normal subjects.7. With the exception of a very small response attributed to the contribution of cones, no significant changes in pupil size were evoked by uniform ganzfeld steady backgrounds until the intensity of retinal illuminance was so high that appreciable rhodopsin was bleached. This contrast to the changes evoked by weak steady backgrounds in the normal eye.8. Therefore, rod bleaching signals are normal in such retinas but rod signals evoked by real lights are not functional. This supports Rushton's concept as to how bleaching signals influence retinal sensitivity as opposed to the view of Barlow.9. The defect in essential night blindness very probably involves the rod automatic gain control, but because of (4) the cone gain control must be normal.10. Therefore, rod and cone gain control mechanisms must be independent in these night blind retinas and, by analogy, in the normal retina as well.