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Biomedical subjects

S Kitada

Publications and source records attributed to S Kitada.

At least 37 records · Page 2Linked to original sources
PubMed1991

Interferon-gamma inhibits collagen synthesis by human Tenon's capsule fibroblasts in vitro.

Collagen deposition is largely responsible for scar information, an undesirable outcome of glaucoma filtering surgery. Because interferon-gamma (IFN-gamma) has been reported to inhibit collagen synthesis in a variety of cells, the authors examined its effect on collagen synthesis by Tenon's capsule fibroblasts cultured from three patients. In addition, the authors studied the effects of IFN-gamma on fibroblast proliferation. IFN-gamma inhibited collagen synthesis at dosages of 1-10,000 U/ml. The average median effective dose (ED50) was 6.60 U/ml. In contrast, IFN-gamma had no significant effect on cell proliferation in dosages of 0.001-10,000 U/ml. These results suggest that IFN-gamma may be a useful agent for modifying the wound healing response, particularly after glaucoma filtering surgery.

Adult↗
PubMed1990

Time-course of alterations of bladder function following acetone-induced cystitis.

Although chemical cystitis is known clinically to cause decreased bladder function, there are few experimental studies on the progression of, and recovery from chemical cystitis. Mature male rabbits underwent intravesical instillation of 50% acetone solution through a urethral catheter. Micturition profiles showed a marked decrease of the mean and maximal micturition volume and an increase in number of micturitions as early as one day after treatment. The micturition profile gradually normalized between four and eight weeks after instillation. In vivo cystometry showed a very small bladder capacity and low compliance during the first week following instillation, and gradually recovered to control levels by four weeks. Functional studies using the in vitro whole bladder model showed a significant decrease in the ability of the bladder to generate pressure and to empty at three days after instillation. These parameters recovered partially by two weeks, and completely by four weeks. Chemical cystitis induced by intravesical acetone instillation resulted in a severe decrease in the bladder function, i.e. contracted bladder with low compliance and poor ability to generate pressure and empty. However, these changes were reversible within the two month period of study.

Acetone↗
PubMed1990

Evaluation of flow electromyography in patients with benign prostatic hyperplasia.

Combined uroflowmetry and external sphincter electromyography studies were done both preoperatively and postoperatively in patients with benign prostatic hyperplasia. In 56 patients preoperative electromyography during voiding showed silent or markedly suppressed activity in 41 patients (73.2%), while the remaining 15 patients (27.8%) revealed active electromyography. In the postoperative studies, 12 patients revealed active electromyography even after the release of obstruction. The urine flow rate following operation was not drastically improved in the active electromyography group compared to the silent electromyography group. We suppose that long-term urethral obstruction with prostatic adenoma could influence the function of relaxation of the external sphincter muscle in some patients with benign prostatic hyperplasia.

Aged↗
PubMed1990

Bilateral pararenal lymphatic cysts associated with hypertension.

A case of bilateral pararenal lymphatic cysts is reported. These cysts surrounded the renal parenchyma in a multilobulated fashion and were contained in the intracapsular space. The lymphangiography showed the communication between cysts and lymphatic channels. Histopathological findings suggested the possible nature of this lesion to be congenital lymphatic anomalies.

Child↗
PubMed1990

Antiproliferative drugs and human ocular fibroblasts: colorimetric vs. cell counting assays.

Utilizing a rapid colorimetric assay that relates cell number to cytoplasmic hexosaminidase activity, we conducted drug-induced cytotoxicity experiments on human ocular fibroblasts cultured from Tenon's capsule specimens. The effects of two different agents--dimethyl sulfoxide (DMSO) or mitomycin C--on the proliferation of human ocular fibroblasts were studied. Simultaneously the sensitivity of this technique was compared to electronic cell counting with a Coulter counter, a conventional means of quantifying proliferation. Known numbers of cells were exposed to varied concentrations of either DMSO or mitomycin C for 11 days. Cell attachment was quantified after 24 hours, and proliferation was quantified periodically thereafter over the remaining 10 days. Colorimetric data contained a similar or smaller amount of random error than corresponding Coulter values. Both assays identified statistically significant antiproliferative effects and inhibitory effects on cell attachment at higher drug doses; however, Coulter counting alone detected many additional significant effects among lower-dose DMSO and mitomycin treatment groups. Although the hexosaminidase assay displayed lower sensitivity than Coulter counting, it may still be useful to rapidly screen new compounds for strong antifibroblastic effects.

Cell Adhesion↗
PubMed1990

Proliferation of human ocular fibroblasts. An assessment of in vitro colorimetric assays.

Growing interest surrounds the pharmacologic modulation of ocular wound healing and fibroblastic proliferation. Therefore many investigators have developed assays to screen potential antiproliferative drugs on cultured fibroblasts. Such assays are extremely labor intensive, especially when many compounds are tested. Using proliferating human ocular fibroblasts, the authors explored the feasibility of three in vitro colorimetric assays as rapid, simple alternatives to more tedious proliferation assays, such as Coulter counting. These were: (1) the mitochondrial metabolism of a tetrazolium dye, (2) the cytoplasmic activity of hexosaminidase, and (3) the lysosomal uptake of neutral red, a weak basic dye. Serial dilutions of fibroblasts were assayed with each colorimetric technique; Coulter counting was used as a standard. All three colorimetric methods showed strong linear relationships between optical density and Coulter-cell counts. The MTT and neutral-red techniques were relatively insensitive, unable to quantify reliably fewer than 20,000 or 50,000 cells, respectively. On the other hand, the hexosaminidase assay was far more sensitive, reliably detecting a few hundred cells. Despite their differences and limitations, these three colorimetric techniques are useful as inexpensive screens whenever multiple drugs are tested for antifibroblastic effects.

Cell Count↗
PubMed1990

Effects of mithramycin, mitomycin, daunorubicin, and bleomycin on human subconjunctival fibroblast attachment and proliferation.

Scar formation and fibrosis are the most common causes of ultimate glaucoma filtration surgery failure. The authors used Coulter counter, hexosaminidase, and 3H-thymidine assays to evaluate the effects of mithramycin, mitomycin, daunorubicin, and bleomycin on human subconjunctival fibroblast growth in tissue culture. Fifty percent inhibitory doses (ID50) for each drug on different days of incubation with fibroblasts were calculated with these three assays. Among these four drugs only daunorubicin exerted a significant effect on cellular attachment, showing cytotoxicity at 4 x 10(-6) M. However, all drugs had antiproliferative effects. Daunorubicin was the most potent drug in the concentration range studied. Mithramycin had a narrow therapeutic range in tissue culture. Cellular antiproliferative responses to mitomycin and bleomycin were more gradual. These drugs have potential applications in the prevention of glaucoma filtration surgery failure.

Antibiotics, Antineoplastic↗
PubMed1990

The effect of 5-fluorouracil and cytarabine on human fibroblasts from Tenon's capsule.

The in vitro cellular inhibitory effects of two pyrimidine antimetabolites, 5-fluorouracil (5-FU) and cytarabine (ara-C), on the attachment and proliferation of human Tenon's capsule fibroblasts after 1, 2, 3, 5, 7, and 10 days of growth were measured with a Coulter counter, a colorimetric method using the endogenous enzyme hexosaminidase, and 3H-thymidine uptake. Neither 5-FU nor ara-C affected cell attachment. The 50% inhibitory dose (ID50) for 5-FU, as measured by the Coulter counter and hexosaminidase assay, was 0.2 and 0.4 micrograms/ml, respectively, at day 5 and decreased to 0.01 and 0.10 micrograms/ml, respectively, on later days. The ID50 for ara-C as measured by the Coulter counter and hexosaminidase assay was 0.01 and 0.1 micrograms/ml at day 3 and remained constant over time. Much lower ID50s were measured by thymidine uptake for both drugs. These findings may indicate that 5-FU has a delayed effect on cellular proliferation due to conversion into more active metabolites. The ara-C has a direct and constant inhibitory effect on cellular proliferation and is ten times more potent than 5-FU as an antiproliferative drug. Thus ara-C may have clinical utility in preventing failure of glaucoma filtering surgery.

Anterior Eye Segment↗
PubMed1989

Effect of acute complete obstruction on the rabbit urinary bladder.

Studies on the effect of partial bladder outlet obstruction demonstrate that significant alterations in urinary bladder structure and function occur within 24 hours of the creation of the obstruction. These studies suggest that many of the functional and structural alterations following partial outlet obstruction may result from the initial overdistension which occurs within the first 24 hours. In these present studies, we investigated the time course of the effect of complete obstruction of the rabbit urinary bladder on the contractile response to bethanechol and field stimulation and on the muscarinic receptor density. Male White New Zealand rabbits were divided into five groups: controls, four, eight, 20, and 24 hours of complete obstruction. The results demonstrated that there was a significant decrease in both the contractile response to muscarinic stimulation and muscarinic receptor density at four hours following outlet obstruction (at a time when there was no bladder overdistension). The receptor density and contractile response to stimulation further decreased over the 24 hour period. These studies indicate that the initial decrease in muscarinic receptor density and contractile response to muscarinic stimulation may be mediated in part by the high level of spontaneous contractile activity induced by ligation of the urethra.

Animals↗
PubMed1989

In vitro intravesical instillation of anticholinergic, antispasmodic and calcium blocking agents (rabbit whole bladder model).

The systemic side effects accompanying oral pharmacotherapy of neurogenic bladder dysfunction present significant drawbacks to this type of therapy. In these studies we investigated the effect of intravesical administration of anticholinergic, antispasmodic and calcium blocking agents on pressure response mediated by field stimulation and bethanechol. We used the rabbit in vitro whole bladder model for these experiments. The bladder from a mature male NZW rabbit was mounted in an organ bath as a whole bladder preparation. After control field stimulation and bethanechol stimulation, 20 ml. of saline containing the specific drug being evaluated was instilled into the bladder. At 30 minute intervals, the responses to field stimulation and bethanechol were determined. Two hours after instillation of 100 microM of each specific drug, the inhibition of the contractile response to bethanechol and field stimulation (as % inhibition) was as follows: oxybutynin (95%/64%), verapamil (85%/81%), atropine (68%/31%), diltiazem (47%/39%), and imipramine (44%/47%). Atropine and oxybutynin suppressed the contractile response of the bladder to bethanechol to a much greater extent than that to field stimulation, while verapamil, diltiazem and imipramine suppressed the contractile response to bethanechol and field stimulation to approximately the same extent. Two hours after drug instillation, the intravesical solution was washed out and replaced with saline, but the recovery of the bladder contraction was slow and incomplete. The results of this study suggest that the use of self-intravesical instillation to suppress bladder contractility should be a good therapeutic approach for patients with neurogenic bladder, especially those who are already managed by intermittent catheterization.

Administration, Intravesical↗
PubMed1989

Effects of extracorporeal shock wave lithotripsy on urinary excretion of N-acetyl-beta-D-glucosamidase.

We investigated the effect of extracorporeal shock wave lithotripsy (ESWL) on the urinary excretion of N-acetyl-beta-D-glucosamidase (NAG) activities. No significant increases in NAG excretion were recognized between, before and after ESWL. However, there were significant increases in patients with renal calculi who received over 1,000 shock waves. Therefore, we should not neglect renal impairments which could be caused by extracorporeal shock wave exposure.

Acetylglucosaminidase↗
PubMed1988

Autocrine growth of murine lymphoma cells.

By using an assay system in which small numbers of murine T lymphoma cells are stimulated to grow in serum-free medium, we have continued and expanded our previous studies of an autocrine growth factor that we call leukemia-derived growth factor (LDGF). We show that a T lymphoma cell line of immature phenotype, adapted to growth in serum-free medium, produces and responds to LDGF. LDGF activity is distinct from activities of 10 highly purified or recombinant hematopoietic growth factors including IL-1 and IL-2. However, growth-stimulating activity for the murine lymphoma cells is provided by a partially purified human LDGF.

Animals↗
PubMed1988

The functional effect of mild outlet obstruction on the rabbit urinary bladder.

Bladder outlet obstruction has been the subject of numerous studies. In previous studies on severe obstruction, the initial response of the bladder has been to produce an acute overdistension of the bladder resulting in severe tissue damage and functional disorders. This is quite different from the slow onset of outlet obstruction seen in association with benign prostatic hypertrophy (BPH). The present study describes the functional effect of mild outlet obstruction created in a rabbit model, and compares it to a previously described model of severe obstruction. Mild bladder outlet obstruction was created by placing a silicon sleeve (inner circumference 30 mm.) around the bladder neck of mature male NZW rabbits. Individual groups of rabbits were studied at one, seven, and 14 days following the creation of the outlet obstruction. The following studies were performed on each group of rabbits: in vivo and in vitro cystometry, field stimulation and cholinergic stimulation using the in vitro whole bladder model. In addition, the tissue concentration of ATP (adenosine triphosphate) and CP (creatine phosphate) and the muscarinic receptor density were determined. The obstructed bladders showed no significant cystometric difference at one day, but revealed a marked decrease of compliance and capacity at one and two weeks. Unlike the response to severe outlet obstruction, there was no initial acute overdistension of the bladder wall. Although the ability of the obstructed bladders to generate intravesical pressure in response to both field stimulation and bethanechol did not decrease, the ability of both forms of stimulation to empty the obstructed bladders was markedly impaired. The response to field stimulation was reduced to a significantly greater extent than the response to bethanechol, indicating neuronal damage. The muscarinic receptor number per bladder was increased above control at all time periods. The intracellular concentration of ATP and CP in the obstructed bladders was similar to that of control. Our present model of mild obstruction was not accompanied by a massive increase in tissue mass nor was there an overdistension of the detrusor; thus, this model would be a more suitable model for the study of clinical outlet obstruction.

Adenosine Triphosphate↗
PubMed1988

Endotoxemia in patients who underwent ultrasonic lithotripsy and extracorporeal shock wave lithotripsy.

The authors conducted limulus tests of assay blood endotoxin in order to study the fever which often develops after ultrasonic lithotripsy (USL) and extracorporeal shock wave lithotripsy (ESWL). Assays of endotoxin were also conducted after transurethral resection (TUR) and other operations as a basis for comparison. Endotoxemia was observed in 18 among 28 patients (64.3%) who underwent USL, in 8 among 34 patients (23.5%) who underwent ESWL, in 1 among 14 patients (7.1%) who underwent TUR and in 1 among 11 patients (9.1%) who underwent other operations. The incidence of endotoxemia was significantly higher (p less than 0.01 by chi 2 test) in patients who had undergone USL than in those who had undergone ESWL, TUR or other operations.

Endotoxins↗
PubMed1988

Effect of contractile activity on muscarinic receptor density and the response to muscarinic agonists.

Autonomic receptor density can be modulated by alterations in neuronal activity over a relatively short period of time (hours). The current study investigates whether increased in vivo stimulation of urinary bladder smooth muscle can alter muscarinic receptor density and response to muscarinic stimulation. A high degree of reflex stimulation of the urinary bladder (rabbits) was initiated by stricture of the external urethra. Intravesical pressure and intra-abdominal pressure were monitored continuously over a 4-hr time period. At the end of the 4-hr period, the rabbits were sacrificed and isolated strips of bladder body were either mounted in isolated smooth muscle baths for contractile studies or frozen and stored in liquid nitrogen for muscarinic receptor analysis. These studies demonstrated that over 4 hr of urethral stricture there was a significant reduction in muscarinic receptor density from a Bmax of 34 +/- 3.4 fmol/mg of protein in control bladder strips to 22 +/- 2.4 fmol/mg of protein in the experimental group. In association with the decreased muscarinic receptor density, there was a significant and selective decrease in the contractile response to muscarinic stimulation. Similar to the in vivo studies, repetitive field stimulation of in vitro strips resulted in a significant decrease in muscarinic receptor density and a significant and selective decrease in the contractile response to muscarinic stimulation. The results from these studies indicate that muscarinic receptor density, and response to muscarinic stimulation, can be modulated over a relatively short period of time by alterations in the level of neuronal stimulation.

Animals↗
PubMed1987

New method for measuring bladder pressure.

We measured intramural pressure of the bladder using a pressure transducer embedded between bladder mucosa and muscle layers in female dogs. Intravesical pressure was recorded simultaneously by conventional transurethral catheter method. Results from the former showed slightly lower values than the latter, but both correlated well in all pressure ranges.

Animals↗
PubMed1987

Pharmacological characteristics of smooth muscle in benign prostatic hyperplasia and normal prostatic tissue.

Strips of prostatic hyperplastic adenoma and normal prostate were studied by observing the mechanical response to application of certain drugs. The sensitivity of BPH tissue to potassium chloride, phenylephrine and prostaglandins was about double that of normal prostate. The small hyperplastic adenoma showed a higher sensitivity to phenylephrine than the large. However, sensitivity to phenylephrine was almost the same among the various histological types of BPH.

Adrenergic alpha-Agonists↗