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Biomedical subjects

A Nakashima

Publications and source records attributed to A Nakashima.

At least 73 records · Page 4Linked to original sources
PubMed1997

Absence of detectable antibody in a patient infected with human immunodeficiency virus.

Infection with human immunodeficiency virus (HIV) is routinely and easily diagnosed with use of enzyme immunoassay (EIA) test kits. We describe an unusual patient who developed AIDS despite testing negative for antibodies to HIV 35 times over a 4-year period. HIV infection was confirmed by the results of p24-antigen assays and polymerase chain reaction amplification of proviral DNA. Sequence analysis of the virus demonstrated that it was closely related to a strain obtained from the patient's sexual partner. The explanation for this patient's persistently negative EIA results is unclear. However, this case does suggest that physicians who treat patients with AIDS-defining conditions but for whom standard HIV antibody testing is negative should consider the possibility that HIV infection is present and may be identified by additional testing procedures.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Stimulatory effect of phytin on acid production by Lactobacillus casei.

The stimulatory effect of phytin added to skim milk on acid production of Lactobacillus casei was examined. Phytin stimulated acid production of L. casei fairly well. The stimulatory effect of phytin on acid production was not shown when phytin was treated with Dowex 50 (H+) and neutralized by NaOH solution. The incinerated product of phytin maintained almost equal stimulatory effect on acid production as that before processing. The addition of Mn2+ in the amount contained in a reagent phytin augmented the stimulatory effect on acid production markedly. The further addition of Fe3+, Ca2+, Mg2+ and PO4(3-) in amounts corresponding to their contents in the preparation of phytin as well as Mn2+ increased the effect slightly. The four preparations of phytin contained 0.045-0.20% of Mn, and the greater the Mn content was, the greater the potentiation of acid production.

Hydrogen-Ion Concentration↗
PubMed1997

[The significance of p21 expression in gastric cancer].

We examined the expression of p53, p21, cyclin D1, E, and PCNA in 75 cases of gastric cancer by immunohistochemical study and the expression of p21 RNA in cases by in situ hybridization. The rate of stage III, IV cases of p53(+) p21(-) group was significantly higher than that of any other groups. The apportinately 3-year survival rate of p53(+) p21(-) group was significantly lower than either that of p21(+) p53(-) or p53(-) p21(-) group. The 3-year survival rates of positive cases were significantly lower than those of negative cases on both cyclin D1 and E. The positive rate of cyclin E of the p53(-) p21(+) group was significantly lower than that of the p53(+) p21(-) group. The average PCNA Labeling. Index (LI) of the p53(+) p21(-) group was significantly higher than that of the p53(-) p21(+) group. The 3-year survival rate of cases with expression of p21 RNA was higher than that of cases without p21 RNA. Average PCNA L1 of cases with expression of mutant-type p53 was high and the number of poor prognostic cases in cases with expression of mutant-type p53 was large. In contrast, the average PCNA LI of cases with expression of p21 was low and the number of good prognostic cases with expression of p21 was large. These results suggest that p21 suppresses synthesis of DNA via cyclin E and PCNA.

Cyclin D1↗
PubMed1996

Interaction between polyanions and cell nuclei: mechanism of gelatination of nuclei.

We investigated the mechanism by which polyanions gelatinized nuclei of some mouse lymphocytes and ruptured these cells. The gel produced by the addition of dextran sulfate (DS) to mouse lymphocyte nuclei was composed of histones (H1, H2A, H2B, H3, and H4), DS, and DNA. Adding DS to the chromatin obtained from nuclei by micrococcal nuclease (MNase) digestion also produced a gel containing a complex of DS-histones-DNA. When this mixture was further digested by MNase, DNA debris of random sizes was observed instead of the 150-bp repeating units of DNA usually observed when normal nucleosomes are digested with MNase. Removal of DS from the chromatin-DS gel resulted in the regeneration of nucleosomes. These results suggest the following: After entering the cells with damaged cellular membrane, DS extracts histones from nucleosomes to form DS-histone complexes, which then aggregate with the liberated DNA to form a macromolecular gel. Finally, the swelling pressure of the gel destroys the cells.

Animals↗
PubMed1996

Effects of hypothermia during cardiopulmonary bypass and circulatory arrest on sympathetic nerve activity in rabbits.

OBJECTIVES: Little is known about the effect of hypothermia on neural regulation. We investigated the effects of hypothermia during cardiopulmonary bypass (CPB) on control of renal (RSNA) and lumbar sympathetic nerve activity (LSNA), and plasma catecholamine levels. METHODS: We directly measured RSNA (n = 14) and LSNA (n = 6) during CPB in anesthetized rabbits. CPB was performed via cannulae in the aortic root for arterial perfusion and the right atrium for venous drainage. Systemic hypothermia was induced by core cooling. RSNA and LSNA were recorded at the nasopharyngeal temperature of 37, 30, 24, and 18 degrees C and after rewarming up to 37 degrees C while keeping mean arterial pressure at 70 mmHg by altering perfusion flow. Other variables such as blood gases or electrolytes were kept constant. RESULTS: RSNA at the temperature of 30, 24, and 18 degrees C significantly decreased by 91, 97, and 95% from control (37 degrees C), respectively. LSNA decreased by 18, 57, and 89% from control as well. The decreases in RSNA at 30 and 24 degrees C were greater than those in LSNA (P < 0.05). At 18 degrees C both RSNA and LSNA nearly disappeared. Circulatory arrest for 20 min during hypothermia at 18 degrees C caused no increase in RSNA while it increased LSNA. Plasma catecholamine levels at 18 degrees C were not different from those at 37 degrees C. Rewarming to 37 degrees C increased RSNA and LSNA by 321 and 92% from control (37 degrees C before cooling), respectively (P < 0.01). CONCLUSIONS: Hypothermia progressively decreased and rewarming markedly increased sympathetic nerve activity, but the effects of hypothermia on RSNA and LSNA were not uniform.

Animals↗
PubMed1996

Plasma P selectin (GMP-140) and glycocalicin are elevated in preeclampsia and eclampsia: their significances.

OBJECTIVE: We measured the concentrations of plasma P selectin (or GMP-140) and glycocalicin in preeclamptic and eclamptic women. Correlations between these two parameters and blood pressures, platelet counts, or plasma thrombin-antithrombin complex values were evaluated. STUDY DESIGN: By use of enzyme-linked immunosorbent assays we measured the plasma GMP-140 and glycocalicin levels in normal pregnancies (n = 10) and preeclamptic (n = 10) and eclamptic (n = 20) pregnancies. The glycocalicin index was calculated as follows: (glycocalicin x [250 x 10(6)/ml])/(Individual platelet counts). Correlations between plasma GMP-140, glycocalicin, glycocalicin index values, blood pressures, platelet counts, and plasma thrombin-antithrombin complex values were analyzed. RESULTS: Plasma GMP-140 levels were found to be significantly elevated in preeclamptic (p < 0.0005) and eclamptic cases (p < 0.0001) compared with normotensive controls. Plasma glycocalicin (p = 0.01, 0.007) and glycocalicin index (p = 0.005, 0.002) values were also markedly elevated in preeclamptic and eclamptic patients compared with normal pregnant patients. Significant correlations between platelet counts or plasma thrombin-antithrombin complex levels and their corresponding plasma GMP-140 and glycocalicin and glycocalicin index values have been found in preeclamptic and eclamptic cases. However, blood pressures had correlations with GMP-140, glycocalicin, and glycocalicin index values in eclamptic cases. CONCLUSIONS: We demonstrated an elevation of plasma GMP-140 and platelet glycocalicin in preeclampsia and eclampsia. This study also reflects the usefulness of glycocalicin as a marker of platelet activation or turnover and endothelial dysfunction in these diseases.

Adult↗
PubMed1996

Renal denervation prevents intraglomerular platelet aggregation and glomerular injury induced by chronic inhibition of nitric oxide synthesis.

Nitric oxide (NO) inhibits platelet adhesion and aggregation in vitro. In vivo, chronic inhibition of NO synthesis induces nephrosclerosis and hypertension. Although the pathophysiological mechanism of this glomerular injury has not been clarified, sympathetic nerve activation, a potent procoagulant stimulus elicited by NO inhibition, may play a role. To investigate the role of renal sympathetic nerves in the development of renal injury induced by NG-nitro-L-arginine methyl ester (L-NAME), a specific NO synthesis inhibitor, we examined renal histological changes in four groups of Sprague-Dawley rats: (1) sham operated, vehicle treated; (2) sham operated, L-NAME treated; (3) denervated, vehicle treated, and (4) denervated, L-NAME treated. Following renal denervation or sham operation, L-NAME was administered orally for 4 weeks. Chronic NO inhibition induced platelet aggregation and erythrocyte stasis in the glomerular capillary lumen accompanied by electron-microscopic glomerular injury. Renal denervation abrogated platelet aggregation and glomerular injury in L-NAME-treated animals. Thus, chronic NO synthesis inhibition induced intraglomerular platelet aggregation and glomerular injury, which was attenuated by renal nerve denervation. These results suggest that intrinsic NO may have an antithrombotic effect in the glomeruli and may play a protective role in the progression of glomerular injury possibly mediated by renal sympathetic nerves.

Albuminuria↗
PubMed1996

Fibrinolysis during normal pregnancy and severe preeclampsia relationships between plasma levels of plasminogen activators and inhibitors.

The antigen levels of plasminogen activator inhibitor type 1 (PAI-1), plasminogen activator inhibitor type 2 (PAI-2), tissue-type plasminogen activator (t-PA), and urokinase-type plasminogen activator (u-PA) were measured during pregnancy and severe preeclampsia. The PAI-1 and PAI-2 antigen levels increased linearly during pregnancy and promptly returned to the level of non-pregnant women after delivery. The t-PA and u-PA antigen levels increased slowly and linearly during pregnancy. In severe preeclampsia, the PAI-2 antigen level was lower than that observed during the 3rd trimester of normal pregnancy, and the t-PA antigen level was higher than that during the 3rd trimester of normal pregnancy. Immunohistochemical examination of placental tissue showed that the PAI-2 and u-PA antigens were localized in syncytiotrophoblasts. In severe preeclampsia, the PAI-2 and u-PA antigens in placental tissue did not stain as clearly as during the 3rd trimester of normal pregnancy. The PAI-2 and u-PA antigen levels showed a positive correlation with birth weight. Therefore, PAI-2 may be an important marker of placental function and abnormality in pregnancies.

Antibodies, Monoclonal↗
PubMed1995

Maldistribution of the cerebral blood flow in retrograde cerebral perfusion.

Retrograde cerebral perfusion (RCP) through a superior vena caval (SVC) cannula has now become a useful alternative for brain protection during aortic arch operations. However, little is still known about its physiological effects, especially regarding the flow distribution in the brain. We studied the cerebral blood flow distribution under hypothermic conditions using mongrel dogs (n = 6, weighing 9.5 to 14 kg). We measured the cerebral tissue blood flow of the cortex with a laser Doppler flowmeter and cerebral tissue blood flow of the medulla using the hydrogen clearance method. The cerebral blood distribution at 28 degrees C with a whole body bypass flow of 100 ml/kg per min and aortic pressure of 88.3 +/- 20.4 mmHg was used as a control. Then the body temperature was decreased to 20 degrees C and the descending aorta was cross-clamped just distal to the origin of the left subclavian artery to establish antegrade cerebral perfusion (ACP). The perfusion flow was decreased to 54.8 +/- 12.4 ml/kg per min so as to make the aortic pressure similar to the control conditions. After measuring the cerebral blood flow distribution in ACP, the perfusion was then switched to RCP through the bilateral internal maxillary vein and the SVC pressure was kept at 40 mmHg. In RCP, the cerebral blood flow of the medulla was quite similar to that in ACP (12.4 ml/min per 100 g versus 15.2 ml/min per 100 g, NS). In contrast, the cerebral blood flow of the cortex significantly decreased to 16% of the flow in ACP (7.8 perfusion units versus 50 perfusion units, P < 0.01). Because of the maldistribution of the cerebral blood flow in RCP, careful attention should be paid to the clinical application of this method.

Animals↗
PubMed1995

Influence of boiling water treatment on surface roughness and surface microstructure of set gypsum (dental stone).

The influence of boiling water treatment on the surface roughness and surface microstructure of set gypsums was investigated. Typical surfaces before and after immersion in boiling water were compared by means of SEM observation, the Knoop hardness test, and a surface roughness test. The surfaces of set gypsums were rougher than that of an acrylic resin plate, and after immersion in boiling water, highly roughened surfaces and thinner crystal bodies were observed on each specimen under SEM. The knoop hardness of set gypsums was considerably lowered after boiling water immersion. That of die stones was the same or lower than set dental stones. The results showed that even brief immersion in boiling water had profound effects on the dental stone cast, resulting in rougher surfaces and lower hardness of set gypsums.

Calcium Sulfate↗
PubMed1995

[Intraperitoneal distribution of drug after gastric surgery].

To evaluate intraperitoneal distribution of drug after surgery, a radiographic study using peritoneography was performed. Five cases with positive intraoperative cytology of gastric carcinoma were studied. The tip of the subcutaneous injection catheter was located in the Douglas's fossa intraoperatively. As control group, 7 cases of inguinal hernia who underwent radical resection for gastrointestinal carcinoma and 2 cases who failed intraperitoneal chemotherapy through injection port, underwent peritoneography. The distribution of contrast medium in the peritoneal cavity was compared between groups. (Conclusion) The distribution of drug after gastric surgery was observed in all of the peritoneal cavity below the transverse colon. Distribution was not observed in the region where lymphadenectomy or bursectomy was done. The peritoneum has an important role in the distribution of drugs in the peritoneal cavity.

Cisplatin↗
PubMed1994

Formation of alpha-helix 88-98 is essential in the establishment of higher-order structure from reduced lysozyme.

Lys96 and Lys97 in lysozyme are located at the C terminus of alpha-helix 88-98. The positive charges of these residues are supposed to stabilize the helical structure, and these residues are conserved as the basic amino acids among c-type lysozymes. The renaturation rate of reduced mutant lysozyme, where both Lys96 and Lys97 were mutated together to Ala, was slower than that of native lysozyme at pH 8.0 and 37 degrees C by SH-SS interchange reactions. In order to investigate the reason, the peptide fragment 36-105 (where we can obtain information of the interaction between helix 88-98 and Trp62 and Trp63 residues) was prepared. CD spectra were compared between peptide fragment 36-105 and its acetylated form, where the positive charges of Lys96 and Lys97 were eliminated, and it was elucidated that the displacement of positive charges at the C terminus of the helix caused the shift of the advantageous structure of the fragment from alpha-helix to coil. Moreover, we obtained evidence that there was interaction of the helix with Trp62 and/or Trp63, which maintained a thermodynamically stable higher-order structure. Therefore, these results suggest that the formation of alpha-helical structure in 88-98 is a significant factor in the establishment of native structure from reduced lysozyme.

Amino Acid Sequence↗
PubMed1994

The efficacy of fluconazole in treating prosthetic valve endocarditis caused by Candida glabrata: report of a case.

A case of active prosthetic valve infective endocarditis (PVE) due to Candida glabrata was successfully treated by the systemic administration of fluconazole. A 66-year-old Japanese man with infective endocarditis of unknown etiology underwent aortic and mitral valve replacement to treat severe aortic and mitral regurgitation associated with multiple organ failure. Postsurgical cultures of arterial blood were repeatedly positive for C. glabrata, and therefore fluconazole was administered either intravenously or orally at a dose of 400 mg/day for 46 days. During that time the signs of inflammation including fever such as an elevated white blood cell count and the presence of C-reactive protein (CRP) all improved while the blood cultures became negative. Fluconazole is thus considered to be effective in treating PVE caused by C. glabrata. When administering this treatment, it is also important to monitor the patient's renal and liver function.

Aged↗
PubMed1994

Risk factors for recurrent Chlamydia trachomatis infections in women.

OBJECTIVE: We evaluated risk factors for recurrent Chlamydia trachomatis infections in women. STUDY DESIGN: We used a retrospective cohort design to examine predictors of recurrent infection in the 38,866 female residents of Wisconsin whose first reported C. trachomatis infection occurred between 1985 and 1989. RESULTS: Young age at first reported infection was the strongest predictor of recurrent C. trachomatis infection, after adjustment for covariates. Adolescents < 15 years old had an eightfold increased risk, those 15 to 19 years old had a fivefold increased risk, and women 20 to 29 years old had a twofold increased risk of recurrent C. trachomatis infection, compared with that among women 30 to 44 years old. In 54% of those aged < 15 at initial infection and 30% of those aged 15 to 19, recurrence developed. Other characteristics associated with recurrence included black race, residence in Milwaukee County, coinfection with gonorrhea, and past sexually transmitted diseases; receiving care in a family-planning clinic appeared protective. CONCLUSIONS: Implementation of strategies to reduce the markedly elevated risk of recurrent chlamydia infections is urgently needed in female adolescents.

Adolescent↗
PubMed1994

Mutagenic and carcinogenic significance and the possible induction of lung cancer by nitro aromatic hydrocarbons in particulate pollutants.

Studies of genotoxicity and carcinogenicity of nitro aromatic hydrocarbons focus on their high mutagenicity for bacteria and mammalian cells. Nitrobenzo[a]pyrenes (NBPs) and related nitroazaarenes also are extraordinarily mutagenic. 3-Nitro-6-azabenzo[a]pyren-N-oxide was found to be a more potent mutagen than 1,8-dinitropyrene. Mutagenicity of NBPs was associated with the position of substitution of the nitro function when nitrogen dioxide (NO2) was substituted at the third position on the benzo[a]pyrene (BP) structure, as in 3,6-dinitrobenzo[a]pyrene but not in 1,6-diNBP. The NBPs were reduced by a rat liver postmitochondrial fraction to nitroso- and subsequently to amino-derivatives. Therefore, tumoral action in rats was induced at significant levels by subcutaneous injection of 3,6-diNBP, but no tumors were observed in rats given 1,6-diNBP. Carcinogenic nitropyrenes were detected in the resected lung of a patient with lung cancer. It is suggested that the presence of nitropyrenes and the resulting tumor were due to exposure to by-products of combustion of heavy oil. The patient was a nonsmoker and farmer who had bred chickens for 40 years. He used heavy oil for heating the chicken house. Similarly, a group of Chinese people at high risk of developing lung cancer was selected to determine the initiator of lung cancer. Lung cancers were obtained from six Chinese female nonsmokers who were living in Fuyuan County, China. Polycyclic aromatic hydrocarbons were detected in resected lung specimens; they were benzo[k]fluoranthene, BP, benzo[g,h,i]perylene, and pyrene. These cases were associated with exposure to soot from combustion of coal usually used for heating and cooking indoors.

Adult↗
PubMed1994

[A case of renal hypouricemia associated with IgA nephropathy--with special reference to changes in serum uric acid and uric acid clearance in a clinical course exceeding 15 years].

We report a case of IgA nephropathy associated with renal hypouricemia. The patient's renal function had decreased gradually during the previous 15 years, resulting in chronic renal failure. Levels of serum uric acid and uric acid clearance were 1.0 mg/dl and 39.4 ml/min, respectively. Pyrazinamide suppression test indicated that the patient had defective tubular reabsorption of uric acid at the presecretory site. The serum uric acid level elevated linearly to 5.0 mg/dl during the 15-year period, in parallel with a change in serum creatinine level, giving a significantly positive correlation coefficient of 0.9776. The ratio of uric acid and creatinine clearances showed no significant change, although both decreased during the 15 years. These results were a different from those in patients with chronic glomerulonephritis, including IgA nephropathy, where the serum uric acid level had shown no significant correlation with serum creatinine level above 2.0 mg/dl and the ratio of uric acid clearance and creatinine clearance had exponentially elevated after the latter decreased below 30-40 ml/min. The patient presented here has defective tubular transport of uric acid at the site of urate reabsorption, and appears to show a different tubular dysfunction response from patients with chronic glomerulonephritis and decreased renal function.

Creatinine↗
PubMed1993

[Analysis of MDR1 (multidrug resistance) gene expression by RT-PCR].

Multidrug resistance to anticancer drugs proved to be related to the MDR1 gene which encodes the P-glycoprotein, an energy-dependent drug-efflux pump for lipophilic drugs. We investigated the expression of the MDR1 gene in clinical samples by RT-PCR. The subjects were all resected cases of 14 colorectal cancers, five gastric cancers, two esophageal cancers, two gallbladder cancers and 20 lung cancers. Adrenal gland was used as a positive control. Total RNA was extracted from a fresh tissue sample. The cDNA was synthesized from 1 microgram of total RNA using reverse transcriptase. With the above cDNA as the template, amplification of the 157-bp fragment of the MDR1 gene was performed using PCR. The PCR product was polyacrylamide gel-electrophoresed and ethidium bromide-stained. In addition, a dot blot analysis was performed to quantify the amount of PCR product. Since PCR was performed simultaneously under the same conditions, the PCR product was quantified at four stages, from (3+) to (-), to indicate the degree of expression of MDR1 mRNA. Adrenal gland showed (3+)-(2+) and colorectal cancer exhibited mostly (2+)-(1+). Both cancerous and non-cancerous areas evidenced a similar degree of expression in the cases of colorectal cancer. The MDR1 gene was expressed at low levels in other digestive tract cancers and in lung cancer. The levels of MDR1 expression revealed no correlation to either histological type or clinical stage. The present method may contribute to designing anti-cancer protocols.

Antineoplastic Agents↗