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Biomedical subjects

H Baba

Publications and source records attributed to H Baba.

At least 253 records · Page 14Linked to original sources
PubMed1994

Enhanced neoplastic lesion development with adenine-induced experimental multicystic nephropathy by adenine--a model system for the analysis of renal tumor generation in long-term hemodialysis patients.

To cast light on the high incidence of renal cell tumors (RCT) in long-term hemodialysis patients, the role of background multicystic nephropathy was studied in a rat model. Group 1 animals were initially given N-ethyl-N-hydroryethylnitrosamine (EHEN) then subjected to adenine feeding until killing during weeks 20-27. Groups 2 and 3 received EHEN and adenine, respectively. All rats receiving adenine developed multicystic nephropathy. The incidence of renal cell hyperplasias (RCH) and multiplicities of both RCH and RCT in Group 1 were significantly increased as compared with Group 2, suggesting multicystic nephropathy provides favorable environment for tumor development.

Adenine↗
PubMed1994

Isolation of human nm23 genomes and analysis of loss of heterozygosity in primary colorectal carcinomas using a specific genomic probe.

Genomic clones of nm23-H1 and -H2 were isolated. The nm23-H1 and -H2 genes were located in a tandem array 4 kilobases apart. Each genome contained 5 exons and most of the splicing sites in the exon-intron junctions of two isotypes were essentially identical. A probe derived from intron 4 of nm23-H1 was used to examine the loss of heterozygosity (LOH) in primary colorectal carcinomas. Twenty-nine of 42 samples were informative and LOH was found in 3 of these 29. In all three samples with LOH, cancer tissues expressed lower levels of nm23-H1 mRNA when compared with those without LOH.

Amino Acid Sequence↗
PubMed1994

Synaptic responses of substantia gelatinosa neurones to dorsal column stimulation in rat spinal cord in vitro.

1. To study the mechanism of dorsal column stimulation-induced depression of nociceptive transmission in the spinal cord, synaptic responses evoked in dorsal horn neurones by dorsal column and dorsal root stimulations were examined in a horizontal spinal cord slice of the adult rat. Intracellular recordings were made from substantia gelatinosa (SG) neurones. 2. All SG neurones examined received monosynaptic inputs and/or polysynpatic inputs from both dorsal column and dorsal root. A delta fibres were probably responsible for the synaptic responses. The responses evoked by dorsal column stimulation were similar to those evoked by primary afferent A delta fibre stimulation. 3. Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by dorsal column A delta fibres were depressed by 6-cyano-7-nitroquinoxaline-2,3-dione, suggesting that these fibres released L-glutamate or a related amino acid as a transmitter. 4. In 38 of 101 SG neurones, dorsal column stimulation evoked an initial EPSP followed by fast and/or slow inhibitory postsynaptic potentials (IPSPs). These IPSPs reversed polarity at a membrane potential of -73 +/- 2 mV. The fast IPSPs observed in 16 of the SG neurones (42%) that received inhibitory inputs were depressed by strychnine, while the slow IPSPs observed in 22 SG neurones were depressed by bicuculline. In a few cells, a long-lasting slow IPSP with a much slower time course was detected; this IPSP was insensitive to strychnine and bicuculline, and reversed polarity at a membrane potential near -90 mV. 5. Repetitive stimulation of the dorsal column depressed the amplitude of monosynaptic EPSPs evoked by dorsal root stimulation. 6. The responses of SG neurones to dorsal column stimulation had configurations and durations similar to responses to dorsal root stimulation, and may be mediated largely by the same A delta fibres. However, a C fibre-mediated response could not be detected in SG neurones from dorsal column stimulation, although dorsal root stimulation could evoke C fibre-mediated monosynaptic EPSPs in 18 of 88 SG neurones (20%). 7. These observations suggest that SG neurones receive abundant A delta but not C fibre inputs from the dorsal column and that dorsal column stimulation inhibits primary afferent transmission in the spinal cord both by reducing transmitter release from primary A delta fibres and by hyperpolarizing SG neurones.

2-Amino-5-phosphonovalerate↗
PubMed1994

Changes in parathyroid hormone receptors during chondrocyte cytodifferentiation.

The purpose of this study was to investigate the relationship between changes in parathyroid hormone (PTH) receptor levels and chondrocyte maturation during endochondral ossification. Chondrocytes were isolated from the growth plate of rabbit ribs and maintained in the presence of 10% serum in mass cultures. Treatment with PTH-(1-84) and a PTH-(1-34) fragment suppressed the increases in alkaline phosphatase activity and in type X collagen and 1 alpha,25-dihydroxyvitamin D3 receptor levels and abolished 45Ca incorporation into mineral, all of which occurred in parallel untreated cultures in the hypertrophic (terminal) stage. These effects of PTH were observed at low concentrations (10(-10) to 10(-9) M) and within 24-48 h of treatment. PTH-(1-84) and PTH-(1-34) also increased [35S]sulfate incorporation into newly synthesized proteoglycans. In contrast, the middle and carboxyl-terminal fragments of PTH tested had little effect on proteoglycan synthesis or terminal differentiation. The binding of 125I-PTH-(1-34) to cells in the growth plate was greater than that to cells in liver, skin, muscle, brain, or kidney. When the correlation between binding levels and stage of maturation was examined, we found that 125I-PTH-(1-34) binding to its 72-kDa receptor was low in resting and proliferating chondrocytes, increased 10-fold in matrix-forming chondrocytes, and thereafter decreased in hypertrophic chondrocytes both in vitro and in situ. Scatchard analysis revealed that the changes in PTH binding were due to changes in the number, and not in the affinity, of the receptor. The changes in PTH-(1-34) binding paralleled those in [35S]sulfate incorporation into proteoglycans. These findings suggest that stage-dependent increases in PTH/PTH-related peptide receptor levels localize the hormone stimulation of proteoglycan synthesis and inhibition of precocious hypertrophy in the matrix-forming zone of growth plates.

Alkaline Phosphatase↗
PubMed1994

Prognostic significance of the number of positive lymph nodes in gastric carcinoma.

A total of 195 patients with node-positive gastric carcinoma who were treated by curative gastrectomy and lymphadenectomy were studied to evaluate the prognostic significance of the number of metastatic lymph nodes. Univariate analysis showed that the number and level of positive nodes, tumour size and depth of invasion, and type of gastrectomy were significantly related to patient survival. Multivariate analysis indicated that the number of positive nodes (up to six versus seven or more; relative risk 2.91), depth of invasion (three levels; relative risk 1.83) and histological type (well versus poorly differentiated; relative risk 0.63) were independently correlated with survival. The results indicate that the total number of positive nodes is the most significant prognostic factor in patients with node-positive gastric carcinoma.

Adenocarcinoma↗
PubMed1994

Role of intraoperative assessment of lymph node metastasis and serosal invasion in patients with gastric cancer.

The clinical diagnoses of nodal status (N) and tumor invasion (T) were performed intraoperatively during 1499 consecutive operations for gastric carcinoma and compared with subsequent pathologic diagnoses. An accurate macroscopic diagnosis of N stage was difficult; overall accuracy was only 56.6%. Intraoperative assessment of T stage (particularly of serosal invasion) was correct for 93.2% of early stages of the disease with invasion confined to the mucosa or submucosa (pT1) when the pathologist assessed the T stage in the resected specimen, for 95.6% of advanced tumors invading the serosa (pT3), but for tumors of an intermediate stage with invasion involving the muscularis propria or the subserosa (pT2) in only 41.9% of cases. Macroscopic overestimation occurred in 58.1% of cases with pT2 tumors, which were characterized by carcinomas in the upper third of the stomach, tumors larger than 5 cm, carcinomas of the ulcerating type, differentiated adenocarcinomas, tumors invading the subserosa, and those accompanied by lymph node metastasis or liver metastasis. The overestimated group had a significantly poorer prognosis than the correctly assessed cases (P < 0.05). Since multivariate logistic regression analysis showed that the significant risk factor related to the inaccurate intraoperative assessment of T stage was tumor size, the error in diagnosis may correlate with a greater degree of tumor spread. Surgeons should decide their therapeutic approach at the time of surgery on the basis of their intraoperative assessment of tumor spread. We recommend extensive surgery followed by adequate chemotherapy when serosal invasion is suspected at surgery.

Adenocarcinoma↗
PubMed1994

Laminoplasty following anterior cervical fusion for spondylotic myeloradiculopathy.

Eighteen patients with spondylotic myeloradiculopathy who had undergone expansive laminoplasty after anterior cervical fusion were reviewed. The average period from the initial to the second operation was 7.8 years. Excellent neurological improvement occurred in 4 patients, good in 6, fair in 4 and poor in 4. Radiographs at the time of the second operation showed spinal canal stenosis in 11, and 12 showed dynamic spinal canal stenosis immediately above the fused area. A narrow spinal canal adds to the risk of recurrence. When spinal stenosis is treated by anterior cervical fusion, additional laminoplasty should be carried out to prevent structural compromise occurring adjacent to the fused vertebrae.

Adult↗
PubMed1994

Total en bloc spondylectomy for solitary spinal metastases.

We have developed a technique for total en bloc spondylectomy through a posterior approach and now report our experience of 20 patients with a solitary or localised metastasis in the thoracic or lumbar vertebrae. There are two steps: an en bloc laminectomy, followed by en bloc resection of the vertebral body with an oncological wide margin and the insertion of a vertebral prosthesis. Pain was relieved in the 17 patients who could be assessed; 11 of the 15 patients with a neurological deficit were much improved, impending paralysis being prevented in 5 patients. There have been no local recurrences. Nine patients are at present alive with a mean follow up of 17.4 months.

Adult↗
PubMed1994

Anterior decompression and fusion for cervical myeloradiculopathy secondary to ossification of the posterior ligament.

The authors reviewed 85 patients who had undergone anterior decompression and cervical fusion for myeloradiculopathy due to ossification of the posterior longitudinal ligament. There were 72 males and 13 females; the average follow up was for 8.3 years. Sixteen patients (group I) underwent one vertebra subtotal spondylectomy with fusion, 58 (group II) two vertebra subtotal spondylectomy, and 11 (group III) three vertebra subtotal spondylectomy. Neurological recovery was assessed on the grading system of the Japanese Orthopaedic Association. The patients in group I had an average improvement of 75%, in group II 72% and in group III 23%. The severity of compromise of the spinal cord did not affect the postoperative improvement. Duration of disease, previous injury and advanced neurological symptoms all affected neurological recovery. Spondylectomy of at most two vertebrae, with fusion, is recommended for ossification of the posterior longitudinal ligament. If there is more extensive involvement laminoplasty may be indicated.

Cervical Vertebrae↗
PubMed1994

Intermittent priapism associated with lumbar spinal stenosis.

Nine patients with intermittent priapism associated with lumbar spinal stenosis are described. They had severe intermittent claudication and priapism when walking, and 7 had sensory disturbances affecting the lumbosacral nerve roots at rest. Radiographs showed degenerative central stenosis in 6, and degenerative spondylolisthesis in 3. Seven were treated by surgical decompression and 2 refused operation. Six of the 7 had improvement in their priapism, but symptoms recurred in one as a result of spondylolisthesis developing after operation.

Aged↗
PubMed1994

Curative local control of malignant tumors in the acetabulum by intraoperative radiotherapy.

As treatment for malignant tumors in the acetabular region of the pelvis, radiotherapy, mainly in the form of intraoperative radiotherapy (IORT), was carried out in four patients. One had a malignant fibrous histiocytoma of bone and three had metastatic tumors from the stomach and lung. Over follow-up period, ranging from 3 to 46 months, satisfactory limb function was preserved in three patients; the fourth suffered from femoral nerve palsy as a complication of IORT. Cessation of growth was observed radiologically in all the tumors, and curative local control was proven histologically in two patients at autopsy.

Acetabulum↗
PubMed1994

Laser flow cytometric studies on the intracellular accumulation of anthracyclines when combined with heat.

The effects of heat on intracellular accumulation of anthracyclines were investigated by laser flow cytometry analysis. Sarcoma-180 cells were exposed to Adriamycin (ADM), epirubicin (EPIR), daunomycin (DM), THP-Adriamycin (THP), ME-2303 (ME) and KRN-8602 (KRN) at 37 degrees C and at higher temperatures. There was a dose-dependent increase in the fluorescence intensity of all drugs at 37 degrees C, but heat varied the fluorescence intensity of each drug. At 43 degrees C the cellular fluorescence of ADM and EPIR increased by approximately 200%, but for DM the increase was 110-130%. The cellular fluorescence of THP and ME was little affected by heat, and heat reduced that of KRN to 80-90%. Each drug showed was unique in the relationship between drug exposure time and the fluorescence intensity at 37 degrees C and 43 degrees C. Cytotoxicity determined by the MTT assay was enhanced with heat in the cases of ADM and EPIR, but not with DM, THP, ME, or KRN. Thus, ADM and EPIR are expected to show enhanced antitumor activities when given in combination with hyperthermia.

Animals↗
PubMed1994

Effect of gastrectomy on the pharmacokinetics of tegafur, uracil, and 5-fluorouracil after oral administration of a 1:4 tegafur and uracil combination.

The effects of gastrectomy on the pharmacokinetics of UFT, a combined oral preparation of 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur) and uracil at a molar ratio of 1:4, were examined in 26 patients with macroscopic Stage I gastric cancer. In all, 200 mg UFT (in terms of tegafur) was given to 17 patients who underwent partial gastrectomy (9 cases of Billroth I reconstruction, 8 cases of Billroth II reconstruction) and to 9 patients who underwent total gastrectomy with modified Roux-en-Y reconstruction. Before the operation, the area under the curve (AUC) for tegafur, uracil, and 5-fluorouracil (5-FU) was 79.28 +/- 26.88, 4.41 +/- 1.78, and 0.51 +/- 0.20 micrograms h ml-1, respectively. Partial (Billroth I and II) and total gastrectomy did not alter the AUC of tegafur, and partial gastrectomy using the Billroth I and II methods decreased the AUCs of uracil and 5-FU during the first 2 weeks postoperation. However, plasma levels of uracil and 5-FU reverted to preoperative values at 3 months postsurgery. Our findings show that when UFT is prescribed for patients treated in the early postoperative period following partial gastrectomy for cancer, dose increases and the timing of administration should be given close attention.

Administration, Oral↗
PubMed1994

Identification of novel mRNAs expressed in oligodendrocytes.

To identify new proteins, which are expressed in oligodendrocytes and which may have a functional role in myelination, a rat oligodendrocyte cDNA library was screened using differential and subtractive screening techniques. Ten clones that have elevated levels of expression in brain were isolated. Two of these clones were characterized further and one clone, pC26.H2, was found to be closely related to mouse stearoyl-CoA desaturase 2 (SCD2), which catalyzes the synthesis of unsaturated fatty acid. From Northern blot and in situ hybridization studies, SCD2 mRNA was expressed primarily in brain with lower levels found in lung and spleen. In brain sections, SCD2 mRNA was found primarily in oligodendrocytes, although mRNA was detected at a low level in neurons, in particular in Purkinje cells in the cerebellum. Northern blot analysis of the other clone, p973.HB, indicated that it was expressed more selectively in brain. In mixed glial cultures oligodendrocytes were the only cells that expressed this mRNA, whereas in brain, neurons expressed this mRNA at a higher level than in oligodendrocytes. This clone is being actively pursued because of its unique expression exclusively in oligodendrocytes and neurons.

Animals↗
PubMed1994

Laparoscopic splenectomy.

A technique for laparoscopic splenectomy is described. The patient is placed in the right semidecubitus position and pneumoperitoneum is prepared. The splenic artery and vein are exposed near the hilum, using a laparoscopic ultrasonic dissector. The larger vessels are doubly ligated, and the spleen is resected and maneuvered into a nylon surgical sack; the sack is removed through a 2-cm incision along the midaxillary line. This procedure has been used for four patients requiring splenectomy for benign disease, and the outcome has been entirely satisfactory for all concerned.

Adult↗
PubMed1994

Effect of hepatectomy on glucose metabolism in the dog.

The response of whole-body glucose uptake and oxidation and hindlimb glucose and lactate balance was investigated using the hyperinsulinemic, euglycemic clamp in 12 sham-operated control dogs and 10 hepatectomized dogs. A combination of radioactive (NaH14CO3) and stable (U-13C-glucose) isotope tracers was used to quantify glucose kinetics and oxidation. The insulin concentration was increased to approximately 5,000 microU/mL. Mean glucose uptake rates across the hindlimb were similar, 7.72 and 8.06 mumol.kg-1.min-1 for hepatectomy and sham-operated groups, respectively. Lactate release across the hindlimb also showed no significant differences between the two groups. Therefore, it was concluded that the liver did not affect peripheral glucose uptake in response to supramaximal insulin infusion under these experimental conditions. On the other hand, the mean glucose infusion rate during the last 60 minutes of the insulin clamp in the hepatectomy group was significantly decreased compared with that in the sham-operated group, 57.11 versus 46.29 mumol.kg-1.min-1, respectively (P < .05). Consequently, the maximal capacity of the liver of the anesthetized dog to clear glucose in response to supramaximal insulin infusion appears to be approximately 10.8 mumol.kg-1.min-1, which is about 20% of the total glucose infused. Isotopic data showed that most hepatic glucose uptake was oxidized. In contrast, most peripheral glucose uptake appeared to be stored as glycogen.

Animals↗
PubMed1994

Postoperative immunochemotherapy including streptococcal lysate OK-432 is effective for patients with gastric cancer and serosal invasion.

The effects of postoperative immunochemotherapy including the streptococcal preparation OK-432 on the rate of peritoneal recurrence and survival time after curative resection were studied in 36 patients with gastric cancer. Patients randomized to group B received 18 months of a therapy that is widely used in Japan for patients with gastric cancer: mitomycin C (MMC) and UFT, a combination of tegafur and uracil in a molar ratio of 1:4. Patients randomized to group A received the same drugs given to group B plus an intraperitoneal injection of OK-432 on postoperative day 0 and intradermal injections of OK-432 for 18 months at 2-week intervals. There were no differences between the two groups in any known prognostic factor or dose of any drug received, except for OK-432. There was no difference in the toxicity rates between the groups. The concomitant administration OK-432 and anticancer drugs significantly decreased the rates of peritoneal recurrence and lengthened survival time (P < 0.05).

Adjuvants, Immunologic↗