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Biomedical subjects

N Hamada

Publications and source records attributed to N Hamada.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Changes in blood flow and skin reaction following radiation therapy].

Skin blood flow (SBF) during radiation therapy was measured and compared with skin reaction to examine the relationship between skin reaction and blood flow. The SBF of 50 patients including 16 with head and neck (H&N) cancer, 13 with breast cancer and eight with lung cancer were analyzed. In the H&N patients, SBF was increased according to the treated dose, while in the breast cancer patients SBF was slightly increased at 10 Gy, and did not change up to 40 Gy. In the lung cancer patients SBF was not increased until 20 Gy, and thereafter increased moderately at 30 Gy. Among H&N, breast and lung cancer patients, the most severe skin reaction was observed at the earliest time in breast cancer patients, while blood flow was only slightly increased. This must have resulted in a relatively higher skin dose than the reference point dose in breast cancer patients. Therefore, differences in the relationship between SBF and skin reaction were observed among different types of cancer patients. However, in H&N cancer patients, SBF was increased as skin dose increased. Skin blood flow could be a good indicator by which to estimate skin reaction quantitatively when the daily skin dose is around 1.6 Gy.

Aged↗
PubMed1994

[A new cellulose-barium gel for computed tomography of the esophagus].

A new oral contrast agent for CT of the esophagus was evaluated for its ability to coat the esophageal lumen in 12 patients with esophageal diseases. This agent is made of carboxymethyl cellulose sodium, potato starch and low-density barium, and has remarkably high viscosity of 13600 centipoise. The esophagus was divided into proximal, mid, and distal segments to analyze the effectiveness of lumenal opacification. The average percent opacification of these segments was 78.7, 86.4, and 63.4%, respectively, for all patients. This agent is expected to play a possible role in the CT diagnosis of esophageal cancer by helping to determine the indications for radical surgery and/or radiotherapy.

Barium Sulfate↗
PubMed1994

[A five-year follow-up of two different 131I treatment methods for Graves' disease and the factors affecting the outcome].

We employed two different methods of 131I treatment for Graves' disease in 285 patients and compared the results between the two. (We also analyzed the factors affecting the treatment outcome.) A single dose of 131I adjusted to the patients' thyroid weight was administered to 180 patients in group 1, while a relatively lower dose of 131I (approximately 30Gy) was given repeatedly to 105 patients in group 2. A 5-year follow-up showed that in group 1, 34% of the patients were euthyroid, 11% hypothyroid, 11% subclinical hypothyroid and 44% still remained hyperthyroid. In group 2, 43% of the patients were euthyroid, 5% hypothyroid, 35% subclinical hypothyroid and 17% hyperthyroid. The factors affecting the outcome of the treatment in group 1 patients were their thyroid weight, the duration of the disease and TRAb levels. No significant correlation was observed between the efficacy of 131I treatment and the patients' sex, age, 24hr 131I-uptake, effective half life of administered 131I or titers of antithyroid antibodies. We conclude that the repeated low dose administration of 131I provides the best outcome in a 5-year follow-up. However, we suggest that an adjusted dose of 131I in relation to the patients' thyroid weight should be employed to obtain a faster therapeutic response.

Adult↗
PubMed1994

[New development of cellulose-ferric ammonium citrate solution as a contrast-enhancement agent for magnetic resonance imaging of esophageal diseases].

For magnetic resonance imaging (MRI) of esophageal diseases, we have developed a new contrast-enhancement agent, cellulose-ferric ammonium citrate solution. Using this agent, the esophageal lumen is easily identified. This agent is expected to play a role in the MRI diagnosis of esophageal cancer and to help determine the indications for radical surgery and/or intracavitary irradiation.

Aged↗
PubMed1994

Detection and typing of human rotavirus in reference to repeated acute gastroenteritis in infants.

Stool specimens from infants who visited a clinic because of acute gastroenteritis were tested for the presence of human rotavirus. Among the samples obtained were specimens taken from seven patients who had visited the clinic at two different times. In six of these seven children, human rotavirus (HRV) was detected in only one of the specimens taken (i.e. during only one of the two visits). One patient was shown to have excreted HRV twice; in both cases the HRV was serotyped to be type 1. The present results indicate that the symptomatic reinfection of HRV was not a widely occurring phenomenon in the group of infants tested.

Acute Disease↗
PubMed1994

Bone marrow transplantation therapy using resistant donors for retrovirus-induced leukaemia in mice.

Infection with Rauscher leukaemia virus (RLV) causes erythroleukaemia, anaemia, viraemia, and splenomegaly, features which develop very quickly in mice of strains susceptible to RLV but more slowly or not at all in strains resistant to RLV. We compared the effects of bone marrow transplantation (BMT) of donor cells obtained from a mouse strain resistant to the virus with the effects of BMT of donor cells obtained from strains susceptible to the virus, in recipient virus-susceptible mice which had previously been inoculated with RLV. Our results indicated that bone marrow transplantation from a marrow-resistant donor, but not from a susceptible donor, delayed the expression of leukaemia and delayed death, although such treatment did not appear to inhibit viral infection in susceptible recipients.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Construction and characterization of a fimA mutant of Porphyromonas gingivalis.

Although fimbriae of Porphyromonas gingivalis have been implicated as playing a major role in adherence to gingival tissue surfaces, no conclusive genetic evidence has yet been obtained. The fimA gene, the determinant for the major fimbrial subunit protein, was cloned and sequenced (D. P. Dickinson, M. A. Kubiniec, F. Yoshimura, and R. J. Genco, J. Bacteriol. 170:1658-1665, 1988). We undertook to inactivate the fimA gene by a homologous recombination technique and examined the fimA mutant for changes in surface properties, including production of fimbriae, adherence to human gingival fibroblasts and epithelial cells, hemagglutinating activity, and surface hydrophobicity. To inactivate the fimA gene, we disrupted a fimA clone by insertion of a DNA segment containing an erythromycin resistance (Emr) gene. This was then delivered into P. gingivalis ATCC 33277 from an Escherichia coli K-12 strain, SM10 lambda pir, by using a mobilizable suicide vector, pGP704; recombination at the fimA locus led to the isolation of a fimA mutant. Disruption of the fimA locus and disappearance of FimA production were confirmed by Southern hybridization with a fimA-specific DNA probe and Western immunoblotting with a monoclonal antibody against the FimA protein, respectively. The fimA mutant constructed failed to express long (0.5- to 1.0-micron) fimbriae from the bacterial surface and had a diminished adhesive capacity to tissue-cultured human gingival fibroblasts and epithelial cells. Observation of the bacteria adhering to human gingival fibroblasts by scanning electron microscopy revealed that the wild-type strain had dramatic local changes in the appearance of the microvilli at the point of contact with large bacterial clumps, whereas the fimA mutant did not. In contrast, neither the hemagglutinating activity nor the surface hydrophobicity was changed in the fimA mutant. These data thus constitute the first direct genetic evidence demonstrating that the FimA protein of P. gingivalis is essential for the interaction of the organism with human gingival tissue cells through a function(s) encoded by the fimA gene.

Bacterial Adhesion↗
PubMed1994

Arteriographic study of the arterial supply of the foot in one hundred cadaver feet.

The arterial supply of 100 human cadaver feet (87 cadavers) was investigated by stereoscopic arteriography and was compared phylogenetically to that of the macaque foot. The deep plantar arch was always well developed and complete, whereas the superficial plantar arch was usually slender and incomplete. The first proximal perforating artery arising from the dorsalis pedis artery formed the main component of the deep plantar arch in 82% of the feet. The second proximal perforating artery arising from the dorsal rete contributed to the deep plantar arch in 43% of the feet, and formed most of the arch in one foot. The dorsal rete was classified into four groups of variants based on the arterial source of the second dorsal metatarsal artery. These were the arcuate artery (25%), distal lateral tarsal artery (12%), proximal lateral tarsal artery (6%), and nondorsal rete (57%) variants. In the first intermetatarsal space, the dorsal and plantar metatarsal arteries shared a common trunk in 54% of the feet, but this did not occur in the other intermetatarsal spaces. The second dorsal metatarsal artery arose from the dorsal rete in 43% of the feet, and this artery was quite large, sometimes being the largest of all the dorsal and plantar metatarsal arteries. Variations of the arterial supply found in humans sometimes resembled the typical pattern found in the macaque.

Adult↗
PubMed1994

Low serum aminotransferase activity in patients undergoing regular hemodialysis.

Of 150 patients undergoing regular hemodialysis (HD), 14 (9.3%) and 12 (8.0%), respectively, showed low serum activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). An investigation was conducted to elucidate the underlying mechanisms in 20 patients with low serum AST and/or ALT activity. Fifty-five percent of the patients with low aminotransferase activity manifested serum levels of pyridoxal phosphate (PLP) that were lower than normal. Serum PLP levels correlated neither with AST nor with ALT activity. Oral administration of vitamin B6 to the cases with low aminotransferase activity resulted in an increase in pre-hemodialysis aminotransferase activity. Addition of vitamin B6 in vitro to the sera from the patients with low aminotransferase activity did not increase the values when the added vitamin B6 was within the physiological range, but did increase when added in larger (pharmacological) amounts. However, aminotransferase activity increased, but PLP levels remained unchanged when these values were compared before and after HD. On the other hand, guanase being within the normal range in all cases studied, did not change after HD. Although our study does not correlate with vitamin B6 deficiency, but rather with some uremic substance(s) which interfere(s) with the enzyme reaction as a cause of low aminotransferase activity, the fact that less than 10% of our patients showed low AST and/or ALT points to the latter possibility, suggesting the need of further study.

Adult↗
PubMed1993

Cancer of the gallbladder associated with anomalous junction of the pancreatobiliary duct system without bile duct dilatation.

The aim of this study was to delineate clinical features and prognosis of cancer of the gallbladder associated with anomalous junction of the pancreatobiliary duct system without bile duct dilatation, and to determine methods for managing the disease. A retrospective study of seven patients is presented. A further 27 cases from the Japanese literature were reviewed retrospectively with regard to method of treatment and prognosis. In 11 of 18 patients in whom staging was known the tumour was stage V, representing advanced disease. In seven of 34 cases curative operation was performed; only two patients survived for > 3 years. This poor outcome was due largely to delayed diagnosis of cancer of the gallbladder. Prophylactic cholecystectomy is recommended in patients with this anomalous junction without bile duct dilatation or a malignant lesion in the gallbladder, because of the high incidence of cancer of the biliary tract.

Adenocarcinoma↗
PubMed1993

Arteries to the great and second toes based on three-dimensional analysis of 100 cadaveric feet.

Three-dimensional arteriography was used to analyse the arterial supply of the great and second toes of 100 cadaveric feet down to the microsurgical level. This information will aid in successful composite tissue transfers of these toes to the hand. The arterial blood supply of the great toe came principally from the first dorsal metatarsal a. (78%) and the first plantar metatarsal a. (22%), and secondarily from the medial tarsal aa. and the three terminal branches of the medial plantar a. For the second toe, the first dorsal metatarsal a. (78%) and the first plantar metatarsal a. (22%) supplied blood from the medial side, and the second dorsal metatarsal a. (78%) and the second plantar metatarsal a. (22%) supplied blood from the lateral side. Seven arterial patterns were found in the interdigital web space. The so-called general pattern was seen in the first web space in 65% of the feet examined. In the second web space it was found in 85%. The first intermetatarsal space sometimes contained a large artery arising directly from the dorsalis pedis or first proximal perforating a. as well as the first dorsal and first plantar metatarsal arteries. In this space, arterial patterns were classified into 4 types and 9 subtypes based on the origins and proximal courses of these arteries. The so-called standard pattern was found in only 19% of the feet, while an arterial pattern with a common proximal trunk on the plantar side for the first dorsal and first plantar metatarsal aa. was found most frequently (46%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Genetic transformation of Porphyromonas gingivalis by electroporation.

Porphyromonas gingivalis was transformed by electroporation using the DNA of plasmid pE5-2, or its derivative, pYT7. Prior to transformation, pE5-2 was transferred from Escherichia coli to P. gingivalis strains by conjugation (mobilization with R751), and the plasmid DNA was purified from the P. gingivalis transconjugants. Transformation occurred when the recipient strain and the donor strain from which the plasmid DNA was purified were homologous. If they were heterologous, transformation did not take place or did so at a very low frequency. This suggested that a restriction-modification system is present in P. gingivalis strains. Plasmid pYT7 was derived by removing an 8.0 kb AvaI fragment from pE5-2 that was purified from P. gingivalis cells. It has several single-cutting restriction sites such as EcoRI, AvaI and ClaI usable for gene cloning, though it was not stable enough in P. gingivalis cells, probably because the rep gene was derived from a relatively distant species, Bacteroides eggerthii.

Conjugation, Genetic↗
PubMed1993

A case of pheochromocytoma complicated with acute renal failure and cardiomyopathy.

We encountered a case of pheochromocytoma which was characterized by the sudden onset of acute renal failure and pulmonary edema. Acute renal failure was rapidly improved after surgical removal of the tumor. This patient was also found to have a hypertrophied, dilated and hypokinetic left ventricle as assessed by echocardiography. Two years after tumor resection, cardiac size and function were normalized. This shows that a catecholamine-induced cardiomyopathy is reversible.

Acute Kidney Injury↗