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Biomedical subjects

K Kitazawa

Publications and source records attributed to K Kitazawa.

At least 19 recordsLinked to original sources
PubMed1998

Guillain-Barré syndrome associated with IgG anti-GM1b antibody subsequent to Mycoplasma pneumoniae infection.

Sera from patients with Guillain-Barré syndrome (GBS) frequently have antibodies to various gangliosides. We report a girl with GBS after Mycoplasma pneumoniae infection who had serum IgG antibody to GM1b ganglioside as well as the cold agglutinins. The cold agglutinins are polyclonal IgM autoantibodies to 'I' antigen on erythrocytes. Ganglioside GM1b contains the terminal moiety shared with sialylated I antigen, a main receptor for M. pneumoniae. In this patient, the anti-GM1b antibody may be elicited in a similar mechanism producing anti-I antibody, and functioned in the development of GBS.

Agglutinins↗
PubMed1998

Color Doppler ultrasound imaging in the emergency management of an intracerebral hematoma caused by cerebral arteriovenous malformations: technical case report.

OBJECTIVE AND IMPORTANCE: Ruptured arteriovenous malformations (AVMs) are important causes of spontaneous intracerebral hemorrhages. This is a report of emergency hematoma removal, avoiding damage to the nidus of the AVM, using intraoperative color Doppler imaging. CLINICAL PRESENTATION: A 38-year-old woman suddenly presented with coma. The patient underwent emergency surgery immediately after admission, without preoperative angiographic examination, because of progressive neurological deterioration caused by a massive hematoma in the right basal ganglia, as diagnosed with computed tomographic scanning. INTERVENTION: A right frontotemporoparietal craniotomy was performed. Intraoperative ultrasound imaging with a color Doppler system (EUP-NS32, 5 MHz; Hitachi Medical, Tokyo, Japan) clearly demonstrated a nidus complex in the hematoma. Based on the imaging, effective decompression of the hematoma was performed without damage to the AVM complex. CONCLUSION: Color Doppler imaging (with real-time availability) of an atypical hematoma provided significant information on the vascular lesion causing the hematoma and could reduce the surgical risks during emergency evacuation of large intracerebral hemorrhages resulting from ruptured AVMs.

Adult↗
PubMed1997

Non-genomic mechanism of 17 beta-oestradiol-induced inhibition of contraction in mammalian vascular smooth muscle.

17 beta-Oestradiol (E2) at 0.1-10 microM directly inhibited various tonic and phasic smooth muscle contractions. The mechanism(s) of oestrogen-induced inhibition of contraction was studied using intact and permeabilized strips and isolated single cells of smooth muscle. 2. In endothelium-denuded vascular smooth muscle, E2 attenuated high K(+)-induced force development and myosin light chain phosphorylation, and produced rapid and reversible relaxation. There were no significant differences in these inhibitory effects between tissue types (femoral artery vs. portal vein), species (rat vs. rabbit) or sexes. 3. The inhibitory potencies of several steroidal and non-steroidal oestrogen analogues were examined and their effects were for the most part stereo-specific. However, two steroids with negligible affinities for the nuclear oestrogen receptor also strongly inhibited high K(+)-induced contraction. 4. Genomic modulators including a protein synthesis inhibitor, an RNA synthesis inhibitor, and oestrogen receptor antagonists did not affect the inhibitory actions of E2. Inhibitors of cyclic nucleotide-dependent protein kinases did not reduce the E2 effect. 5. Ca2+ release from intracellular stores by agonists and by inositol 1,4,5-trisphosphate (IP3) does not appear to be modulated by E2. Neither pretreatment with ryanodine nor with thapsigargin affected the E2-induced inhibition of high K(+)-induced contraction. 6. E2 had no effect on either normal or GTP gamma S-increased Ca2+ sensitivity of the regulatory and contractile apparatus. 7. E2 and its analogues rapidly inhibited voltage-dependent L-type Ca2+ channel currents in isolated smooth muscle cells. Repetitive stimulation was not required for E2-induced inhibition of the currents. 8. This study strongly suggests that at pharmacological concentrations oestrogen primarily reduces Ca2+ influx through inhibition of L-type Ca2+ channels in a non-genomic manner and decreases myosin light chain phosphorylation and contraction of smooth muscle.

Animals↗
PubMed1996

The relationship of adhesion molecules and leukocyte infiltration in chronic tubulointerstitial nephritis induced by puromycin aminonucleoside in Wistar rats.

We studied the expression of adhesion molecules on infiltrating leukocytes and tubular cells in chronic tubulointerstitial nephritis associated with puromycin aminonucleoside (PA) nephrosis. Rats received injections of PA (2 mg/100 g body wt) weekly for the first 3 weeks and every other week thereafter. Rats were killed at 0, 3, 5, 8, and 12 weeks after the start of injections. From the third to the fifth week, the initial infiltrating cells in interstitial tissue were mainly CD4+ T lymphocytes. At the fifth week, ICAM-1, CD44, and hyaluronate were expressed on infiltrating cells in interstitial tissue. At the eighth week, the number of infiltrating cells reached a peak and consisted of T lymphocytes (CD4, CD8) and macrophages (ED1, MHC class II, CD11b, and CD18). The severity of interstitial infiltration was correlated with the degree of proteinuria and with ICAM-1 expression. Our results suggest that CD4+ T lymphocytes may contribute to the production of initial tubular injury. Expression of ICAM-1 helps mononuclear cells migrate to the interstitium. In addition, expression of CD44 and hyaluronate may play important roles in the chronicity of tubulointerstitial nephritis.

Animals↗
PubMed1995

Infantile subdural fluid collection: diagnosis and postoperative course.

The authors reviewed 47 cases of infantile subdural fluid collection with regard to diagnosis and postoperative course after placement of a subdural-peritoneal shunt. CT scan with contrast enhancement proved to be an important diagnostic modality, showing vessels in the subarachnoid space as high-density spots. Utilizing this technique, we were able to differentiate the following varieties of fluid collection: (1) subdural fluid collection, in which enhancing vessels were seen on the brain surface, (2) subarachnoid fluid collection, in which vessels were on the inner table of the cranium, and (3) coexistence of subdural and subarachnoid fluid collections, in which vessels were between the inner table of the cranium and the brain surface. The postoperative course of subdural fluid collection was characterized as follows: (1) the subdural fluid collection decreased first, with increased subarachnoid fluid collection; (2) the subarachnoid fluid collection remained after the disappearance of subdural fluid collection; and (3) the brain expanded again later. Subdural fluid collection disappeared about 1 month after the shunt operation, which could lead occlusion of the shunt system. Postoperative enlargement of the subarachnoid space was an early indicator of the efficacy of the subdural-peritoneal shunt.

Cerebral Angiography↗
PubMed1995

[Guillain-Barré syndrome associated with external ophthalmoplegia, consciousness disturbance, and extensor plantar responses: an overlap between Guillain-Barré syndrome and Bickerstaff's brainstem encephalitis].

A 14-year-old girl developed diplopia and ataxic gait following upper respiratory tract infection. On day 3, she became lethergic, but was easily roused on stimulation. Neurologic examinations showed external ophthalmoplegia, tetraplegia, tendon areflexia, and extensor plantar responses. CSF protein was 93 mg/dl with normal cellurality on day 25. Serum in the acute phase of her illness had autoantibodies to gangliosides GQ1b and Ga1NAc-GD1a. An EEG showed bilateral theta activity. Results of ABR, SEP and blink reflexes suggested the presence of intramedullary brainstem lesion. She received plasmapheresis on days 4, 5 and 6. Neurological signs immediately improved. Five months after onset of neurological symptoms, she had no neurological abnormalities except for tendon areflexia. Electrophysiologic studies returned to normal concurrently with her clinical improvement. This patient demonstrates an overlap between Guillain-Barré syndrome and Bickerstaff's brainstem encephalitis.

Adolescent↗
PubMed1994

[Fulmonant group A streptococcal infection accompanied by massive pulmonary hemorrhage and subsequent asphyxia: a case report].

A case of fulminant group A streptococcal infection occurring in a 6-year-old Japanese child is reported. She was accompanied by massive pulmonary hemorrhage and subsequent asphyxia. She initially had pharyngalgia with fever. The cephalosporin antibiotic was given orally for 3 days. Three days after that recurrence of fever and pharyngalgia was noted. Twelve hours later tachypnea and a sudden onset of hemoptysis was noted. She manifested DOA (dead on arrival) and died in the emergency room. Autopsy revealed the presence of numerous cocci in the vessels and massive pulmonary hemorrhage. Streptococcus pyogenes was isolated from the blood. The serotype of this group A streptococcal organism was typed as M4, T4, which produces exotoxin type B and C, which was sensitive to the penicillins.

Asphyxia↗
PubMed1994

Elevation of transforming growth factor-beta 1 level in cerebrospinal fluid of patients with communicating hydrocephalus after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional polypeptide that controls the production of extracellular matrix protein. Platelets store a large quantity of TGF-beta 1, which is released at hemorrhage. We recently reported that human recombinant TGF-beta 1 induced communicating hydrocephalus in mice. The aim of this study was to determine whether TGF-beta 1 is related to the development of communicating hydrocephalus after subarachnoid hemorrhage (SAH). METHODS: TGF-beta 1 in the cerebrospinal fluid of 24 patients with SAH was measured with enzyme-linked immunosorbent assay. The levels were compared between hydrocephalic and nonhydrocephalic groups. Western blot analysis was performed to determine active TGF-beta 1 in the cerebrospinal fluid. RESULTS: TGF-beta 1 rapidly decreased from the onset of SAH. The level of TGF-beta 1 of 13 patients showing ventricular dilatation with periventricular low density on computed tomographic scan was 1.07 +/- 0.37 ng/mL on days 12 through 14, which was significantly higher than 0.52 +/- 0.21 ng/mL in patients without ventricular dilatation (P < .02). Furthermore, the TGF-beta 1 level of patients who had undergone ventriculoperitoneal shunt (n = 11) was 1.11 +/- 0.09 ng/mL on days 12 through 14, which was also higher than the level of the nonshunt group (n = 13) (0.56 +/- 0.22 ng/mL; P < .01). A 25-kD band was demonstrated by Western blot analysis in the cerebrospinal fluid of a patient with SAH. CONCLUSIONS: Our results strongly suggest that TGF-beta 1 plays an important role in generating communicating hydrocephalus after SAH.

Adult↗
PubMed1994

[Studies on cell-mediated immunity (CMI) in the glomeruli: immunization with GBM antigen from Masugi nephritis in Wistar-Kyoto rats].

The role of cell-mediated immunity in glomerular injury has been extensively studied, but the precise mechanism remains obscure. This study was undertaken to determine whether the homologous glomerular basement membrane (GBM) combined heterogeneous anti-GBM antibody would induce cell-mediated immunity. Wistar-Kyoto rats were divided into three groups; group I rats were immunized with homologous GBM antigen that was derived from Masugi nephritis and emulsified in complete Freund's adjuvant (CFA); group II rats were immunized with homologous GBM antigen that was derived from normal rats and emulsified in CFA; group III rats were immunized with CFA only. Group I rats demonstrated proteinuria on days 7 and 10 after immunization. Histologically, mesangial cell proliferation and cell infiltration were observed in the glomeruli. No changes in tubulointerstitial tissue. CD4-positive cells, CD8-positive cells and macrophages were found in the glomeruli, and mononuclear cells were found in the glomerular capillary lumen. Group II and Group III rats demonstrated no proteinuria and no histological changes. These findings indicated that the altered GBM obtained antigenicity and induced cell-mediated immunity in the glomeruli.

Animals↗
PubMed1993

[Clinicopathological significance of immune complex (IC) along the tubular basement membrane (TBM) in lupus nephritis].

This paper reports on the clinicopathological significance of IC along the TBM in lupus nephritis. Renal biopsies were performed on 60 patients with SLE. All of the patients demonstrated immunoglobulin deposits in the glomeruli, and 16 of them also showed immune deposits along the TBM. The IgG in the glomeruli or along the TBM completely disappeared after incubation with human IgG, IgG Fc fragments, but not with human F(ab')2, rabbit or rat IgG. These results suggest that IgG along the TBM are similar in nature to IC in the glomeruli and that the IC are composed of IgG rheumatoid factor. The square of tubulointerstitial lesions was more severe in the group with IgG along the TBM than in the group with no IgG along the TBM (5.85 +/- 9.88% vs 1.29 +/- 3.72%). In addition of this, the group with IgG deposits along the TBM frequently demonstrated type IV lupus nephritis. Although the renal function was not significantly different in the both groups, the serum complement level was lower in the cases with IC deposits in the TBM. From these results, it is suggested that IC deposits along the TBM as one of the important inflammatory agents lead to the severe forms of tubulointerstitial injury and show the active stage of the disease in SLE patients.

Antigen-Antibody Complex↗
PubMed1993

[CT guided transsphenoidal surgery: report of nine cases].

We have developed a Computed Tomography system for use in the operating room and applied this CT system to intraoperative monitoring during transsphenoidal surgery. This system includes Toshiba TCT-300 CT system, mobile CT scanner gantry, digitally controlled operating table and head fixation system. Between June 1989 and Dec. 1989, CT guided transsphenoidal surgery was carried out in 9 cases in our department. The suprasellar masses were visualized directly during transphenoidal surgery and were removed safely and efficiently. Under this CT monitoring system the surgeon can obtain accurate information about the location and volume of residual tumor as well as about the important surrounding deeper structure. Another advantage of this system is that the digitally controlled operating table makes it possible to keep the patient in a head-up position, which lessens oozing from the parasellar region during transsphenoidal surgery. We believe the best application of this method is that for pituitary tumor with moderate suprasellar extension. Nine cases were reported in this paper which were operated on using this system. To our knowledge, this is the first report of use of intraoperative CT monitoring during transsphenoidal surgery.

Adenoma↗
PubMed1992

Anatomically corrected malposition (ACM) with subpulmonary infundibulum in a calf: clinico-morphologic case report.

A Japanese black calf with cyanosis, tachycardia, tachypnea and systolic murmur died of hypoxemia and cardiac insufficiency on the 38th day after birth. We could not establish the diagnosis during it's life. However, anatomically corrected malposition (ACM) with ventricular septal defect was confirmed at autopsy. There was situs solitus of the viscera and atria with atrio-ventricular discordance and ventriculo-arterial concordance. The ventricles demonstrated l-loop, i.e. on the right-sided ventricle there was a markedly enlarged morphologic left ventricle, and on the left-sided ventricle there was a hypoplastic morphologic right ventricle with a stenotic tricuspid valve and Ebstein-like deformity. The right posterior aorta originated from the left ventricle. The pulmonary artery arose from the left-sided right ventricle via infundibulum. There was a fibrous continuity between the aortic and mitral valve. We considered that this is the first reported case of bovine ACM.

Animals↗
PubMed1992

[Involvement of allergic mechanism in minimal change nephrotic syndrome (MCNS)].

In this study we evaluated the involvement of allergic mechanisms in patients with adult onset MCNS (17 cases) by measuring serum IgE levels and RAST scores to house dust 1 (H.D.1), house dust 2 (H.D.2), Dermatophagoides farinae (D.f.), Dermatophagoides ptenonyssinus (D.p.). Out of the 17 cases, three cases showed high levels of IgE (more than 1000 IU/ml) and the mean level of serum IgE was 877 IU/ml before treatment. All cases were treated with steroid and/or cyclophosphamide. After the treatment, all cases returned to remission. The level of IgE decreased to the normal range in four out of seven cases which had shown high levels of IgE before treatment. RAST was carried out on seven of the 17 cases. RAST scores for D.f. and D.f. were found to be positive in three cases, but these became negative in two cases after treatment. In five cases relapsed, the all cases showed to have the increased level of serum IgE and two of four cases which were examined RAST score showed to have the increased RAST score for D.f. and D.p. Thus, the data indicated that allergic mechanism, especially against D.f. and D.p. antigen, seemed to play one of the factors in the pathogenesis of MCNS.

Adolescent↗
PubMed1991

Analysis of ultrastructural immune deposits in passive heymann nephritis by double-staining methods with electron microscopy.

In this study, we located and quantitated the ultrastructural glomerulus-bound immunoglobulins of passive Heymann nephritis from 10 min through 64 days using the double immunogold staining method. At the early stage (10 min to 21 days), rabbit IgG was found predominantly comparing rat IgG. With time (from 21 days to 32 days), rat IgG increased, although rabbit IgG was almost the same as at the early stage. At the late stage (64 days), rat IgG was predominantly found in all of the dense deposits on the glomerular basement membrane, whereas rabbit IgG was decreased. Thus, the double staining method was useful to analyze the composition of the immune complex and also to elucidate the immunopathogenesis of immune complex-mediated glomerulonephritis.

Animals↗