Biomedical subjects

H Akamatsu

Publications and source records attributed to H Akamatsu.

At least 91 records · Page 5Linked to original sources

PubMed1994

Inhibitory effect of prostaglandin E1 on human neutrophil function.

Neutrophils accumulated in the lung are thought to play a pivotal role in the pathogenesis of host auto-injury such as adult respiratory distress syndrome (ARDS). We investigated the effect of prostaglandin E1 (PGE1) on several aspects of human neutrophil function. PGE1 significantly decreased reactive oxygen species (ROS), (O2-, H2O2, OH.) generation by neutrophils as well as neutrophil phagocytosis and chemotaxis. In contrast, the drug did not affect the levels of ROS generated by a cell-free ROS generating system. In addition, intracellular calcium concentrations ([Ca2+]i) in neutrophils stimulated by f-Met-Leu-Phe were decreased in the presence of PGE1. These data suggest that the reduction in ROS production and neutrophil phagocytosis and chemotaxis by PGE1 may contribute to the effectiveness of the drug in host auto-injury including ARDS. The suppression of the increase in [Ca2+]i may at least be responsible for inhibition of these neutrophil functions by PGE1.

Adult↗

PubMed1994

The antibiotic susceptibility of Propionibacterium acnes and Staphylococcus epidermidis isolated from acne.

We studied the susceptibility of antimicrobial agents to Propionibacterium acnes (P. acnes) and Staphylococcus epidermidis (S. epidermidis) isolated from acne patients. We measured the minimum inhibitory concentrations (MICs) of the following five drugs: roxithromycin (RXM), erythromycin (EM), clindamycin (CLDM), minocycline (MINO) and ofloxacin (OFLX), which are frequently used to treat acne and skin infections. We found many resistant strains of S. epidermidis and some resistant strains of P. acnes. There was a correlation between the resistance of S. epidermidis and the former therapy for acne, but no distinct correlation between the resistance of P. acnes and the former therapy for acne.

Acne Vulgaris↗

PubMed1994

Sensitivity of Staphylococcus aureus and Streptococcus pyogenes isolated from skin infections in 1992 to antimicrobial agents.

We studied the efficacy of antimicrobial agents against Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) isolated from skin infections in 1992. For S. aureus, we measured the minimum inhibitory concentrations (MICs) of the following 10 drugs: methicillin (DMPPC), cefaclor (CCL), gentamicin (GM), erythromycin (EM), clindamycin (CLDM), minocycline (MINO), vancomycin (VAN), fusidic acid (FA), ofloxacin (OFLX) and nadifloxacin (NDFX); for S. pyogenes, we determined the MICs of the following 9 drugs: ampicillin (ABPC), amoxicillin (AMPC), cefpodoxime proxetil (CPDX-PR), erythromycin (EM), clindamycin (CLDM), minocycline (MINO), norfloxacin (NFLX), of loxacin (OFLX) and nadifloxacin (NDFX). These drugs are frequently used to treat skin infections, either systemically or topically. NDFX is a new synthetic fluoroquinolone, recently developed for use as a topical acne medication in Japan. It is used NDFX for acne, but not for skin infections. There were no strains of S. aureus resistant to NDFX, VAN or FA. The resistance (> or = 12.5 micrograms/ml) of S. aureus was highest to GM and lowest to OFLX. Four strains of methicillin-resistant (> or = 12.5 micrograms/ml) S. aureus (MRSA) were found. In contrast, no resistant strains of S. pyogenes were found except to MINO. Only two strains of S. pyogenes were susceptible to MINO. The sensitivity of S. pyogenes to ABPC, AMPC, CPDX-PR, EM and CLDM was very good. All the strains were susceptible at a MIC below > or = 0.05 microgram/ml. However, the S. pyogenes strains were not very sensitive to the new quinolones, especially NFLX. We concluded that penicillins, cephalosporins and macrolides are still effective against streptococcal infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1994

Androgens affect the activity of human sebocytes in culture in a manner dependent on the localization of the sebaceous glands and their effect is antagonized by spironolactone.

To investigate the varying response of the pilosebaceous unit to androgens functional studies were performed on the effects of testosterone and 5 alpha-dihydrotestosterone on cultured human sebocytes derived from different skin regions. In addition, the effect of spironolactone on the proliferation of androgen-stimulated human sebocytes derived from facial skin was evaluated. Testosterone (10(-11) to 10(-5) M), 5 alpha-dihydrotestosterone (10(-11) to 10(-5) M) and spironolactone (10(-12) to 10(-7) M) were added for 10 days as single substances or in combinations to human sebocytes in secondary culture maintained in a serum-free medium. Cell proliferation was assessed using a fluorometric assay. Intracellular lipids were extracted from sebocytes treated with androgens (10(-7) M) for 10 days after confluency. Testosterone inhibited the proliferation of sebocytes derived from the legs with a 50%-inhibitory concentration at 10(-5) M and induced a 50% decrease of intracellular lipids. In contrast, 5 alpha-dihydrotestosterone stimulated the activity of leg sebocytes with a 50% increase of proliferation at 10(-5) M, and a 175% increase of intracellular lipids. On the other hand, the proliferation of facial sebocytes was significantly stimulated by testosterone with a 50%-stimulatory concentration at 10(-6) to 10(-5) M and mostly by 5 alpha-dihydrotestosterone with a 50% enhancement at 10(-8) to 10(-7) M. Spironolactone inhibited the proliferation of facial sebocytes in a dose-dependent manner with a 25%-inhibitory concentration at 10(-9) M. Simultaneous treatment of facial sebocytes with spironolactone and testosterone or 5 alpha-dihydrotestosterone resulted in decreased proliferation when compared to the growth obtained under androgens alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[A case of squamous cell carcinoma of negative tumor shadow arising from pulmonary cyst].

We report a case of 53-year-old man who performed resection of infected cystic lung lesion seen from his childhood. Chest X-ray showed no remarkable change in the wall of the cyst, and tumor shadow was negative. As the chest cavity was severely adhesive, operation was ended in partial resection including the cyst. Pathological study revealed moderately differentiated squamous cell carcinoma replacing the entire cystic wall. Right upper lobectomy and dissection of lymph nodes were performed as second operation. Microscopically, carcinoma was limited in the wall of the cyst.

Carcinoma, Squamous Cell↗

PubMed1994

[A case of micro-metastatic lung adenocarcinoma into adenoma of the thyroid].

In a case of 46-year-old woman, small nodules appeared in the anterior neck which was diagnosed as follicular adenoma of the left lower lobe of the thyroid. Four months before, she experienced resection of the lung and three courses chemotherapy of MVP for stage IIIb well-differentiated lung adenocarcinoma. Pathologically, micro-metastatic lung adenocarcinoma was found in the adenoma. It is very rare occurrence for lung carcinoma to metastasize into adenoma of the thyroid. But when tumors of the anterior neck are found in a patient of lung carcinoma, thyroid tumor must be considered for differential diagnosis.

Adenocarcinoma↗

PubMed1994

[CT guided percutaneous needle biopsy of mediastinal lymph nodes for staging of primary lung carcinoma].

In cases of primary lung carcinoma, diagnosis of metastatic mediastinal lymph nodes using computed tomography (CT) is usually difficult, and mediastinoscopy is highly invasive for patients. By using CT guided percutaneous needle aspiration technique, we diagnosed the metastasis to mediastinal lymph nodes in three cases of primary lung carcinoma. In this method, percutaneous biopsy was easily performed even in obesed patient, and metastatic lymph nodes were differentiated from large vessels by using enhanced CT to avoid dangerous punctures. Furthermore, biopsy of almost all mediastinal lymph nodes may be feasible by using both anterior and posterior approach. This method seems to be very useful for the diagnosis of the staging of primary lung carcinoma.

Adenocarcinoma↗

PubMed1993

Blood flow velocities in the cerebral arteries and descending aorta in small-for-dates infants.

Resistive indices (RI) in the anterior cerebral artery (ACA), basilar artery (BA), middle cerebral artery (MCA) and descending aorta (DA) were obtained in 15 small-for-dates (SFD) infants who were, growth retarded because of maternal pregnancy-induced hypertension and in 20 appropriate-for-dates (AFD) infants matched for gestational age between 24 h and 48 h after birth. The RIs in the MCA, ACA and BA were significantly lower, while the RI in the DA was significantly higher, in the SFD infants than in the AFD infants. These changes in RIs in the SFD infants might be similar to the "brain sparing" effect as reported in growth-retarded fetuses.

Aorta, Thoracic↗

PubMed1993

Spironolactone directly inhibits proliferation of cultured human facial sebocytes and acts antagonistically to testosterone and 5 alpha-dihydrotestosterone in vitro.

Spironolactone produces antiacne effects and has recently been shown to inhibit 5 alpha-dihydrotestosterone (5 alpha-DHT) receptors in human sebaceous glands. We applied spironolactone alone and combined with testosterone and 5 alpha-DHT to investigate its effects on the proliferation of human sebocyte cultures derived from facial skin. Secondary human facial sebocytes in 96-well culture plates were treated for 10 d by a single or combined application of testosterone (10(-8)-10(-5) M), 5 alpha-DHT (10(-8)-10(-5) M), and spironolactone (10(-12)-10(-7) M) in serum-free basal medium. Cell proliferation was assessed in six wells using a fluorometric assay. Testosterone and 5 alpha-DHT significantly stimulated sebocyte proliferation in a dose-dependent manner, the effect being strongest with 5 alpha-DHT. Spironolactone, on the other hand, caused a dose-dependent inhibition (25% and 50% at 10(-9) and 10(-7) M, respectively). Combined treatment of human facial sebocytes with spironolactone and testosterone or 5 alpha-DHT resulted in a lower proliferation than with androgens alone. The fact that spironolactone directly and dose dependently inhibits the proliferation of cultured human facial sebocytes and acts antagonistically to testosterone and 5 alpha-DHT at the cellular level is indicative of a receptor-mediated effect.

Cell Division↗

PubMed1993

Development of the sleep and wakefulness rhythm in preterm infants discharged from a neonatal care unit.

The purpose of this study was to investigate the effect of constant light in a neonatal care unit on the development of the sleep-and-wakefulness rhythm in preterm infants. Two groups of infants (57 preterm infants without other complications and 58 healthy term infants) were prospectively studied over infancy by a day-by-day plot method, by which sleep-and-wakefulness states were recorded at home for more than 14 d to compare developmental courses of the sleep-and-wakefulness rhythm between the two groups at corrected and postnatal ages. In the two groups, there were no significant differences in distribution of emergence of periodicity of sleep states and wakeful states, total sleep time, nocturnal sleep time, diurnal sleep time, longest sustained sleep period, and longest sustained wakeful period at the same corrected ages. Moreover, the SD of the time of onset of the longest sustained sleep period of each subject diminished with increase in postconceptional weeks. The results suggest that the development of the sleep-and-wakefulness rhythm in preterm infants is not necessarily retarded if they are discharged from the neonatal care unit under constant light before an infant's innate biologic clock is mature enough to respond to an environmental cycle; rather it depends on their corrected ages.

Circadian Rhythm↗

PubMed1993

The effect of oxatomide on neutrophil oxygen radical generation.

The effect of oxatomide on reactive oxygen species (ROS) generated both by neutrophils and in a cell-free, xanthine-xanthine oxidase system was examined. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.). Oxatomide significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. H2O2 and OH. generated in a cell-free system were also reduced in the presence of oxatomide. The present study indicates that oxatomide decreases ROS generation presumably by inhibiting the neutrophil oxygen metabolism, and has the ability to scavenge H2O2 and OH.

Cell-Free System↗

PubMed1993

[Study of combination therapy for thymoma: a case of stage IV which presented as total spinal block caused by epidural metastasis and which preoperative combination therapy was effective for minimizing the tumor].

We experienced 24 cases of thymoma in the past 17 years. Associated syndromes as myasthenia gravis and pure red cell anemia (PRCA) were found in 7 patients. Preoperative therapies were done for the cases of stage IV. Total resection of the tumor was performed except 3 cases which ended in exploratory thoracotomy. Postoperative therapies were done except the cases of stage I. Each one case of stage III and IV a whose operation ended in exploratory thoracotomy died of tumors, but latter case had some period of PR after chemotherapy. A case of stage I with PRCA died from pneumonia but other cases of autoimmune disease had been well controlled by medical treatment. A case of stage IVb was first admitted to the hospital for paralysis of bilateral lower limb. After resecting the epidural tumor of thoracic spine, chemotherapy (CAV 1 kur) and radiotherapy (4,200 rad) was performed which was effective for minimizing the antero-mediastinal tumor. Though operation ended in exploratory thoracotomy, majority of the tumor was found to be replaced for fibrous tissue which suggested the effectiveness of the combination therapy. But this case died from pancreatitis during the postoperative therapy. In conclusion, combination therapy of surgical resection and adjuvant radiotherapy & chemotherapy including the care for autoimmune disease is important in the treatment of thymoma.

Adult↗

PubMed1993

Age-dependent basal level and induction capacity of copper-zinc and manganese superoxide dismutase and other scavenging enzyme activities in leukocytes from young and elderly adults.

Several enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase are capable of scavenging reactive oxygen species in in vivo. We assessed both basal levels and the capacity of these enzyme activities to be induced in human leukocytes in response to a variety of agents. Basal activity of copper-zinc SOD, and manganese SOD showed little variation with age. In contrast, the basal activity of the three H2O2 scavenging enzymes, catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase, was significantly higher in younger adults than in elderly individuals. Both manganese SOD and copper, zinc SOD activities were significantly induced by paraquat, interleukin-1, tumor necrosis factor, adriamycin, and bleomycin in lymphocytes and neutrophils from asymptomatic non-aged adults, whereas neither activity was induced in aged individuals. In contrast, glutathione peroxidase activity was significantly induced in both groups of subjects, whereas catalase and D-glucose-6-phosphate dehydrogenase were only slightly induced in either. Enzyme induction with paraquat, adriamycin, or bleomycin was inhibitable by neutralizing antibody to interleukin-1 and tumor necrosis factor, suggesting that the inductions observed with these three drugs are due to the distal mediators, interleukin-1 or tumor necrosis factor released from the cells. Finally, as observed in the regulation of genes in eukaryotes (Storz et al: Bacterial defenses against oxidative stress. Trends Genetics 1990, 6:363-368, ref. 1) O2- and H2O2 seem to differ in the rate of change with age in both basal levels and inducibility under oxygen stress.

Adolescent↗

PubMed1992

Control of human sebocyte proliferation in vitro by testosterone and 5-alpha-dihydrotestosterone is dependent on the localization of the sebaceous glands.

Androgens stimulate the activity of sebaceous glands in vivo. In this study the in vitro effect of androgens on the proliferation of cultured human sebocytes derived from facial and non-facial skin were assessed. Human sebocytes from sebaceous glands isolated from the face and the upper and lower legs of five individuals were cultured in vitro with or without testosterone or 5-alpha-dihydrotestosterone (5 alpha-DHT) at different concentrations (10(-11)-10(-5) M). Cell proliferation was assessed in 96-well culture plates using a fluorometric assay. Testosterone and 5 alpha-DHT stimulated the proliferation of human facial sebocytes in a significant dose-dependent manner. In our system 5 alpha-DHT exhibited the strongest effect; on the contrary, the proliferation of non-facial sebocytes was inhibited by testosterone, whereas 5 alpha-DHT enhanced their growth. The stimulatory effect of 5 alpha-DHT was more prominent on facial than on non-facial sebocytes. These results provide first evidence that the effect of testosterone and 5 alpha-DHT on the proliferation of cultured human sebocytes may depend on the localization of the sebaceous glands at different skin regions.

Adult↗

PubMed1992

Inhibition of neutrophil chemotactic factor production in comedonal bacteria by subminimal inhibitory concentrations of erythromycin.

The effect of 1/10 minimal inhibitory concentrations (sub-MIC) of erythromycin (EM) on human neutrophil chemotactic factor production in comedonal bacteria, Propionibacterium acnes strains, Propionibacterium granulosum strains and coagulase-negative staphylococcus (CNS) strains was assayed using the Boyden chamber method. Sub-MIC of EM significantly suppressed neutrophil chemotactic factor production in all strains of P. acnes, P. granulosum and CNS. Our results suggest that sub-MIC of EM may have an anti-inflammatory action by reducing the inflammatory capacity of comedonal bacteria in inflammatory acne.

Acne Vulgaris↗

PubMed1992

Effect of doxycycline on the generation of reactive oxygen species: a possible mechanism of action of acne therapy with doxycycline.

On the basis of a recent report that minocycline is effective in the treatment of acne inflammation by acting directly as an antioxidant on infiltrating neutrophils, we investigated whether doxycycline might also be capable of reducing the generation of reactive oxygen species, using human neutrophils and a cell-free, xanthine-xanthine oxidase system. The species investigated are superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.). Doxycycline significantly reduced the levels of O2-, H2O2 and OH. generated by both systems. Our results seem to suggest that the clinical effectiveness of doxycycline in the treatment of acne inflammation is due partly to its antioxidant effect on neutrophils.

Doxycycline↗

PubMed1992

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis.

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.

Adult↗

PubMed1992

[Incidence and causes of neonatal seizures in the last 10 years (1981-1990)].

We report the incidence of neonatal seizures in the last 10 years. Between 1981-1990, 28,925 infants were born in the Japanese Red Cross Medical Center. Very low-birth-weight infants (< 1,500 g) were excluded in this study. Seizures were identified in 67 infants (0.23%) during the first 7 days of life. Seizures occurred more frequently in low-birth-weight infants (1,500-2,499 g) than in normal-birth-weight infants (> 2,499 g). Fifty-one infants (0.19%) of 27,276 normal-birth-weight infants and 16 (0.97%) of 1,649 low-birth-weight infants developed seizures. The frequency of seizures was 0.25% during the first 5 years and 0.20% during the second 5 years. In low-birth-weight group, the frequency of seizures decreased form 1.49% to 0.48% during the 5-year periods, and seizures due to post asphyxial hypoxic-ischemic encephalopathy also decreased from 0.14% to 0.06%. The decreased incidence in neonatal seizures during the last 10 years was probably achieved by the progress in intervention of low-birth-weight infants in NICU and by the obstetrical prevention of intrapartum asphyxia.

Female↗