Biomedical subjects

T Ishikawa

Publications and source records attributed to T Ishikawa.

At least 19 recordsLinked to original sources

PubMed1992

[CT of intestinal injuries following blunt trauma].

We retrospectively reviewed 53 CT scans in 42 patients with surgically proven intestinal injury following blunt abdominal trauma. Free air and localized low density fluid were specific signs of intestinal injury. Free peritoneal fluid without a known source, thickened bowel wall, and thickened mesentery were non-specific ones. Specific and non-specific findings were demonstrated in six (22%) and 23 (85%) of 27 CT scans performed within four hours following trauma, and 19 (73%) and 26 (100%) of 26 CT scans performed after four hours, respectively. CT is useful for the diagnosis of blunt intestinal injuries, but early diagnosis is difficult because of the lack of specific signs.

Abdominal Injuries↗

PubMed1992

Report of a patient with POEMS/Takatsuki/Crow-Fukase syndrome associated with focal spinal pachymeningeal amyloidosis.

The authors present the results of an autopsy of a 67-year-old Japanese man with POEMS/Takatsuki/Crow-Fukase syndrome (P/T/CFS) diagnosed in 1972. Each component of the syndrome was gradually recognized after the resection of lumbar vertebral solitary plasmacytoma in 1967. The patient died in 1989 of generalized infection and renal failure. Autopsy revealed in the vertebral canal between the fifth and seventh thoracic vertebrae dorsal pachymeningeal fibrosis, with prominent amyloid deposition that oppressed the spinal cord. This condition was consistent with the final neurologic manifestation of the patient, bilateral motor and sensory disturbance below the sixth thoracic level. Myelopathy remained clinically unnoticed because neurologic disturbance had begun as peripheral polyneuropathy. Normocellular marrow with heterogeneously scattered lambda light chain-positive plasma cells and degeneration of the myelinated fibers of sciatic nerve also were observed. This is the first report of focal spinal amyloidosis associated with P/T/CFS.

Adult↗

PubMed1992

[MR imaging of corpus callosal injuries].

The MR imaging and CT findings of corpus callosal injury were analyzed in 32 of 224 patients with acute head injuries. MR imaging was more sensitive than CT in the detection of callosal injuries. All 9 hemorrhagic lesions were visualized on both MR imaging and CT. Fifteen of 23 nonhemorrhagic lesions were not visualized on CT, although all nonhemorrhagic lesions were visualized on MR imaging. Twenty-four lesions of the corpus callosum were located in the splenium, but no lesion was located in the rostrum. Diffuse axonal shear injuries were visualized in 25 patients with callosal injury as associated traumatic lesions. Twenty-three patients with callosal injury had low initial Glasgow Coma Scale scores (less than 9), but 9 patients had high scores. Associated diffuse axonal shear injuries, especially in the brain stem could be a possible explanation for this difference. MR imaging is useful to detect traumatic lesions of the corpus callosum.

Accidents, Traffic↗

PubMed1992

[Clinical application of 31P MRS to malignant liver tumors--with an emphasis on evaluation of response to therapy].

Malignant liver tumors in 19 cases (13 hepatomas and 6 metastatic tumors) were studied by 31P magnetic resonance (MR) spectroscopy. Five healthy volunteers were also studied. Volume localization was performed using the ISIS sequence. Compared with normal liver, the MR spectra of malignant tumors showed an elevated phosphomonoester (PME) peak relative to beta ATP (p less than 0.005), and tumors were slightly alkaline (pH 7.32 +/- 0.08) before therapy. Nine cases of hepatomas responding to chemoembolization showed extremely reduced signal intensity of spectra. Tumor pH was compared before and after therapy in four cases that showed good response to therapy, and was elevated in all of them. Three metastatic tumors with good response showed reductions in PME and ATP after therapy. MR spectroscopy with adequate localization technique is useful in demonstrating the response of malignant tumors to therapy.

Carcinoma, Hepatocellular↗

PubMed1992

Effects of topical nasal anaesthesia on shift of breathing route in adults.

The position of the soft palate is known to determine the breathing route, but the physiological mechanisms that bring about a shift from nasal to oral breathing are unclear. To test the hypothesis that activation of receptors in the nasal passage may be involved in reflex initiation of oral breathing after nasal obstruction, we investigated respiratory responses to nasal occlusion before and after topical lignocaine anaesthesia of the nasal passages. Eleven volunteers were fitted with custom-made partitioned face masks, which separated nasal and oral passages. Air flow through each passage was detected by changes in airway pressure and carbon dioxide concentration. Nine subjects were habitual nasal breathers both before and after topical anaesthesia with 4% lignocaine. Among these subjects, the time to initiate oral breathing in response to nasal occlusion was significantly shorter before anaesthesia than afterwards (mean 4.4 [SD 2.5] vs 10.8 [7.4] s, p less than 0.01). Similarly, the time to resume nasal breathing after release of nasal occlusion was significantly shorter before topical anaesthesia than afterwards (6.9 [4.9] vs 12.1 [7.8] s, p less than 0.01). Topical anaesthesia did not affect respiration rate, end-tidal carbon dioxide concentration, or arterial oxygen saturation. These findings suggest that in human beings sensory information from receptors in the nasal passage has an important role in controlling the shift of breathing route.

Administration, Topical↗

PubMed1992

Studies on long-term potentiation of the population spike component of hippocampal field potential by the tetanic stimulation of the perforant path rats: effects of a dopamine agonist, SKF-38393.

Long-term potentiation of the field potentials recorded in the dentate gyrus of the hippocampus was observed in freely-moving rats by delivering a brief tetanic stimulation to the perforant path, and the effects of the D1 agonist, SKF-38393, on it was investigated. The field potential was divided into two components; excitatory postsynaptic potential (EPSP) and population spike. In Expt. I, synaptic stimulus-response (S-R) relationship, spike S-R relationship, and EPSP-spike (E-S) relationship were plotted. The estimated slope of the regression line in the spike S-R relationship was enhanced after delivery of the tetanic stimulation (10 pulse at 400 Hz), where that in synaptic S-R relationship was not enhanced. The estimated slope of the regression line in the E-S relationship was also enhanced by the tetanic stimulation. In Expt. II, time-dependent change of the field potential after tetanic stimulation was investigated. The population spike was enhanced significantly for about 2 h following tetanic stimulation, while pEPSP did not change significantly. These changes following tetanic stimulation in Expt. I and II were significantly inhibited by previous administration of SKF-38393 (10 mg/kg, i.p.), and the effect of this drug was dose-dependently antagonized by the D1 antagonist, SCH-23390 (0.1, 0.2 and 0.5 mg/kg, i.p.). These results suggest that a brief tetanic stimulation of the perforant path induces long-term potentiation of the population spike without potentiating the synaptic input in the perforant path-dentate synapses, and that potentiation of the population spike is inhibited by the dopaminergic D1 mechanism.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1992

Nephroblastomas in the Japanese eel, Anguilla japonica Temminck and Schlegel.

Nephroblastomas were observed in 50 Japanese eel reared at a farm for 5 to 9 months from 1989 after collection in the wild. The tumors, arising from the trunk kidney near the anus, were noted externally as abdominal swellings and varied in size from 30 to 75 mm in maximum diameter. Most were elastic, solid, and well encapsulated. Histologically, the nephroblastomas were composed of combinations of three main tissue elements. Spindle- or oval-shaped cells resembling human blastema cells were observed in most tumors to some larger or smaller degree. Although variation was evident from tumor to tumor, and even within the same tumor, the most common histological type was epithelial with formation of alveolar nests, the cells sometimes being arranged in tubular structures simulating normal renal tubules. A muscle tissue element with distinct cross-striations was also observed. Liver metastases were found in one case. Histological examination of apparently normal kidneys from 100 eels revealed one early-stage nephroblastoma. The cause of these tumors is unclear, although they have been discovered with increasing incidence after the spread of indoor eel culture with raised water temperatures (26-27 degrees C) in Japan. Environmental factor(s) associated with the new aquaculture method may thus play a role in their genesis.

Anguilla↗

PubMed1992

Brefeldin A binds to glutathione S-transferase and is secreted as glutathione and cysteine conjugates by Chinese hamster ovary cells.

Radioactively labeled brefeldin A was used to probe for proteins that interact with this metabolite. The most prominent protein labeled after in vivo incubation of Chinese hamster ovary cells with [3H]brefeldin A turned out to have an apparent molecular mass of 26 kDa. Radioactive peptides derived from the [3H]brefeldin A-labeled protein showed sequence identity with glutathione S-transferases, and immunoblotting after two-dimensional gel electrophoresis confirmed this result. In addition, Chinese hamster ovary cells convert the antibiotic to its glutathionyl and cysteinyl derivatives and secrete them rapidly into the medium. From these findings we conclude that detoxification of the antibiotic in mammalian cells occurs via the glutathion S-transferase system. This may explain the often observed reversibility of brefeldin A's action on the steady state of organelles in mammalian cells.

Amino Acid Sequence↗

PubMed1992

[Evaluation of non-contrast-enhanced CT in blunt abdominal trauma].

We compared the findings of noncontrast-enhanced CT with those of contrast-enhanced CT in 126 patients with blunt abdominal trauma to evaluate the usefulness of noncontrast-enhanced CT. In 112 of the patients, visceral injuries were confirmed by surgery or clinical follow-up including CT. Although noncontrast-enhanced CT diagnosed all patients with 12 intestinal injuries requiring immediate surgery, contrast-enhanced CT missed two of these patients because high density hematomas on noncontrast-enhanced CT became isodense after IV administration of contrast material. However, contrast-enhanced CT was superior to noncontrast-enhanced CT in the diagnosis of hepatic and renal injuries. A case of renal artery occlusion was only visualized on contrast-enhanced CT. We conclude that both noncontrast- and contrast-enhanced CT should be performed for the CT evaluation of blunt abdominal trauma.

Abdominal Injuries↗

PubMed1992

Diffusely infiltrating primary colorectal carcinoma of linitis plastica and lymphangiosis types.

A review of 2369 cases of resected primary colorectal carcinoma identified 15 cases of diffusely infiltrating colorectal carcinoma. Depending on the histologic pattern and extent, these cases were classified as linitis plastica (LP) type (seven cases) or lymphangiosis (LA) type (eight cases). The LP type consisted of poorly differentiated adenocarcinoma or signet ring cell carcinoma; it showed an annularly thickened and rigid bowel wall. The LA type consisted of moderately differentiated adenocarcinoma. The colon wall of the LA type was hemilaterally thickened at the mesenteric side. The prognosis was extremely poor for both types. The LP type mainly had peritoneal dissemination (70%), but the LA type frequently had distant metastasis (88%). Early diagnosis and curative operation are important for both types; however, the LA type also requires therapy for distant metastasis.

Adenocarcinoma↗

PubMed1992

Isolation and characterization of a calcium-binding protein derived from mRNA termed p9Ka, pEL-98, 18A2, or 42A by the newly synthesized vasorelaxant W-66 affinity chromatography.

W-66 (N-(2-aminoethyl)-N-[2-(4-chlorocinnamylamino) ethyl]-5-isoquinolinesulfonamide), a newly synthesized isoquinolinesulfonamide, was shown to have a potent vasodilatory action and calmodulin (CaM)-antagonizing action. Using the W-66 affinity chromatographic technique, we purified two Ca(2+)-binding proteins from the EGTA-soluble fraction of bovine aorta. One was CaM and the other was an acidic protein with a molecular mass of 11 kDa. It was tentatively named "calvasculin." Calvasculin was a dimeric protein. Equilibrium dialysis showed that 1 mol of calvasculin (dimer) bound to 1.98 +/- 0.30 mol of Ca2+ in the presence of 10(-3) M Ca2+. Calvasculin failed to activate Ca2+/CaM-dependent enzymes such as myosin light chain kinase, Ca2+/CaM-dependent phosphodiesterase, or Ca2+/CaM-dependent protein kinase II and to inhibit the CaM stimulation of these enzymes. The partial amino acid sequence of calvasculin revealed a high homology to the predicted protein derived from mRNA, named pEL-98, 18A2, 42A, or p9Ka. We also examined the physicochemical and biochemical properties of calvasculin. Using the antibody specific for calvasculin, we obtained evidence that calvasculin is present in abundance in bovine aorta but not in brain, lung, heart, or testis.

Amino Acid Sequence↗

PubMed1992

[Signal contamination problem in three-dimensional localization technique of MR spectroscopy--experiment and an analysis of patient data].

Signal contamination from the surrounding volume was studied using the ISIS sequence, a three-dimensional localization technique. In phantom experiments, contamination decreased with the increase of Tr, regardless of where the contamination originated from. In 52 localized liver spectra with a Tr of 2 sec, PCr contamination was estimated at 3 to 4%, and contamination of ATP signals from the surrounding liver tissue at less than 1%, because of the relatively short T1 of ATP in the liver. In the spectra of brain neoplasms obtained using the simultaneous double-volume selection technique, the PCr ratio in the tumor relative to the control area was high in low grade astrocytoma (0.80, n =8) and low in others (0.45, n = 11). Considering contamination and spectral noise, a PCr ratio of less than 0.4 does not strongly suggest the existence of PCr in tumors. Among 25 cases whose therapeutic processes were monitored by MRS, signal disappearance was observed in two cases in the localized spectra after therapy. In both of them, tumor necrosis was proved pathologically and correlated well with spectroscopic findings. It was found that the ISIS technique suppressed signal contamination to the level of several percents, providing spectra of acceptable quality through localization.

Humans↗

PubMed1992

Intramural metastasis of thoracic esophageal carcinoma.

Of 393 patients with squamous-cell carcinoma in the thoracic esophagus, 60 were found by histologic examination to have intramural metastasis. Metastases in 50 of these were identified by gross inspection. There appeared to be no preference for location proximal to the primary lesion. Eighteen patients had metastasis to the gastric wall, which suggested the existence of communicating lymphatic channels between the wall of the esophagus and the stomach. All 60 primary tumors invaded beyond the submucosa. These 60 patients (group A) were compared with a group of matched control patients without intramural metastasis (group B). The tumor size in group A was significantly larger than in group B (p less than 0.01). The number of patients with lymph-node metastasis was significantly higher in group A (p less than 0.01), and the average number of positive nodes in group A was greater than in group B (p less than 0.01). Recurrent disease in the mediastinal lymph nodes and in the liver is characteristic of group A. The survival curve for patients in group A was significantly lower than that for group B (p less than 0.001). Conventional radiotherapy or chemotherapy after surgery were ineffective in improving prognosis. These results indicate that the presence of intramural metastasis is an important factor to consider when evaluating the prognosis of patients with squamous-cell carcinoma of the esophagus.

Carcinoma, Squamous Cell↗

PubMed1992

Treatment of hepatocellular carcinoma associated with advanced cirrhosis by transcatheter arterial chemoembolization using autologous blood clot: a preliminary report.

Twenty-two patients with hepatocellular carcinoma were treated by a new method of transcatheter arterial chemoembolization using an autologous blood clot as an embolizing agent. All had underlying advanced cirrhosis (14 Child's class B and 8 Child's class C patients). The median follow-up interval was 11 mo (range = 2 to 30 mo). The results of the treatment were compared with those of conventional chemoembolization using gelatin sponge particles for 19 Child's class B patients as historical controls. The survival rate for Child's class B patients treated by the new procedure estimated by the Kaplan-Meier method was 100% at 2 yr, whereas the survival rate for Child's class B patients treated by conventional chemoembolization was 89% at 1 yr and 72% at 2 yr. The survival rate for Child's class C patients was 75% at 1 yr and 50% at 2 yr. Side effects such as pyrexia of more than 38 degrees C or an elevation of the serum bilirubin level of more than 1.5-fold were less common in patients treated by the new method than in those treated by conventional chemoembolization, and thus the new procedure could be performed even for Child's class C patients. The autologous blood clot did not collapse the hepatic arteries even when the embolization was performed repeatedly, and thus fine collateral vessels feeding recurrent hepatocellular carcinoma did not develop. The results suggest that the new chemoembolization using an autologous blood clot is a promising therapeutic procedure in the management of hepatocellular carcinoma associated with advanced cirrhosis.

Aged↗

PubMed1992

Detection of hepatitis C virus by polymerase chain reaction and response to interferon-alpha therapy: relationship to genotypes of hepatitis C virus.

To investigate the relationship between genotypes of hepatitis C virus and response to interferon-alpha therapy, hepatitis C virus RNA was assayed by polymerase chain reaction with three sets of primers and probes in 70 patients with non-A, non-B chronic hepatitis who received interferon-alpha. Twenty-four patients sustained long-term remissions (complete responders). Polymerase chain reaction for 5'-terminal noncoding region detected hepatitis C virus RNA in 94.3% (66 of 70) of the patients. Polymerase chain reaction for nonstructural region 3, in which primers and a probe were synthesized to be identical to hepatitis C virus-J, detected hepatitis C virus RNA in 40 patients. Polymerase chain reaction for nonstructural region 5-in which sequences of primers and a probe were derived from hepatitis C virus-K2, a genotype different from hepatitis C virus-J--detected hepatitis C virus RNA in 17 patients. Only one patient was positive on both nonstructural region 3 and nonstructural region 5 polymerase chain reaction. Nucleotide sequence of clones obtained from 5' terminal noncoding region polymerase chain reaction products of two patients positive on polymerase chain reaction for nonstructural region 3 and negative on polymerase chain reaction for nonstructural region 5 (group 1) corresponded to that of the hepatitis C virus-J group, and those of clones from two patients negative on polymerase chain reaction for nonstructural region 3 and positive on polymerase chain reaction for nonstructural region 5 (group 2) corresponded to that of hepatitis C virus-K2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Effects of transforming growth factor-beta 1 against the inhibitory action of interferon on DNA synthesis and viral replication in hepatitis B virus DNA-transfected cell.

Studies were undertaken to examine the effects of recombinant human transforming growth factor beta 1 (TGF-beta 1) on DNA synthesis and antiviral actions of interferons (IFNs) in HepG2 cell, a hepatoma cell line, transfected with hepatitis B virus (HBV) DNA. The inhibitory effects of IFN-alpha and -gamma on DNA synthesis of HepG2 cells were enhanced in a dose-dependent manner by a simultaneous addition of TGF-beta. The degree of suppression by the reagents was greater in HBV-nontransfected cells than in transfected cells. Inhibition of DNA synthesis was not due to direct cytotoxic effects of the additives, since the viability of HepG2 cells was comparable in the control and treated cultures as determined by trypan blue exclusion. Treatment of HBV DNA-transfected HepG2 cells with IFNs resulted in decrease in production of HB surface and e antigens, and in the level of HBV DNA, but TGF-beta reversed the IFN-induced antiviral state in HBV DNA-transfected HepG2 cells. TGF-beta had no direct effect on HBV replication. These results indicate that rTGF-beta 1 exerts a differential effect against the inhibitory actions of IFN on DNA synthesis and viral replication in HepG2 cells.

DNA, Viral↗

PubMed1992

Cloning and sequencing of the melB gene encoding the melibiose permease of Salmonella typhimurium LT2.

The nucleotide sequence of the melB gene coding for the Na+ (Li+)/melibiose symporter of Salmonella typhimurium LT2 was determined, and its amino acid sequence was deduced. It consists of 1428 bp, corresponding to a protein of 476 amino acid residues (calculated molecular weight 52,800). The amino acid sequence is homologous to that of the melibiose permease of Escherichia coli K12, with 85% identical residues. All, except one, of the amino acid residues that have been reported to be important for cation or substrate recognition in the melibiose permease of E. coli are conserved in the melibiose permease of S. typhimurium. In addition, part of the sequence resembles the lactose permease of Streptococcus thermophilus, the animal glucose transporter (GLUT1), the plasmid-coded raffinose permease (RafB), and the NADH-ubiquinone oxidoreductase chain 4 (Nuo4) of Aspergillus amstelodami.

Amino Acid Sequence↗

PubMed1992

Tetraethylammonium blocks muscarinically evoked secretion in the sheep parotid gland by a mechanism additional to its blockade of BK channels.

Since the secretory cells of the sheep parotid gland contain large numbers of high-conductance, voltage- and Ca(2+)-activated K+ channels (BK channels), we have used tetraethylammonium (TEA), a commonly employed blocker of BK channels, to investigate their role in secretion by this gland. In patch-clamp studies we found that 10 mmol/l TEA applied extracellularly inhibits the BK channel but not a 30-pS K+ channel also seen in this gland. We then showed by in-vivo perfusion that muscarinically evoked secretion is inhibited almost completely by 10 mmol/l TEA. We next used microspectrofluorimetry with fura-2 to demonstrate that muscarinic agonists cause the intracellular free Ca2+ concentration to increase. Unexpectedly, however, we found that 0.3-10 mmol/l TEA inhibited the increase in intracellular free Ca2+ induced by 5.0 mumol/l bethanechol or by 0.1 mumol/l acetylcholine. Consequently we conclude that the inhibition of muscarinically evoked secretion by the sheep parotid gland by TEA cannot be attributed solely to blockade of the BK channel--rather it must be attributed, at least in part, to blockade of some step in muscarinic signal transduction, for instance, receptor-agonist binding or Ca2+ release into the cytosol.

Animals↗