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Biomedical subjects

E Kawakami

Publications and source records attributed to E Kawakami.

At least 55 records · Page 3Linked to original sources
PubMed1995

Short-term oral treatment of canine benign prostatic hypertrophy with chlormadinone acetate.

Ten beagle dogs (4-8 years of age) with benign prostatic hypertrophy were treated daily for 7 or 14 days by a daily oral administration of chlormadinone acetate (CMA), an anti-androgenic preparation, at a dose of 0.5 or 2.0 mg/kg/day. The groups of dogs treated with CMA at a dose of 2.0 mg/kg showed a greater reduction of the prostatic volume during 7 or 14 days of treatment than the group treated with 0.5 mg/kg of CMA. At 56 and 84 days after the start of CMA treatment, prostate volume was reduced to 63 and 79% of the pre-administration volume, respectively. No marked decrease in plasma LH or testosterone was found after the CMA treatment. These results indicate that the therapeutic effects of 7-day oral treatment with CMA at 2.0 mg/kg/day in dogs with BPH last for about three months or longer without side effects.

Administration, Oral↗
PubMed1995

Effect of chlormadinone acetate-pellet implantation on the volume of prostate, peripheral blood levels of sex hormones and semen quality in the dog.

Chlormadinone acetate (GS implant, CMA) pellet, a synthetic luteal hormone preparation, was subcutaneously implanted at 5, 10 and 20 mg/kg in four normal male dogs ranging in age from 3 to 10 years to determine the changes in the prostatic volume, peripheral plasma levels of sex hormones and semen quality. The plasma levels of CMA, LH, testosterone (T) and 5 alpha-dihydrotestosterone (DHT) were measured by radioimmunoassay. The prostatic volume was measured by computed tomography. The semen was collected by digital manipulation. The pellet was removed 26 weeks after implantation. The effects of CMA pellet implantation were examined during implantation and until 22 weeks after removal. The prostatic volume was reduced to 61 +/- 3 (mean +/- S.E., n = 4), 52 +/- 5 (n = 4) and 53 +/- 9 (n = 4)% of the preimplantation volumes in the 5, 10 and 20 mg/kg groups, respectively. The plasma CMA levels in the 10 mg/kg and 20 mg/kg groups peaked at 2 weeks, but were gradually decreased. At 22 weeks after removal of the pellet, the prostatic volume returned to 74-85% of the preimplantation volumes. The plasma LH levels tended to increase after implantation in all groups. The plasma T and DHT levels were slightly decreased in all groups. In the 10 and 20 mg/kg groups, the number of sperm and motility sperm was reduced, and the rate of abnormal sperm increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Changes in peripheral plasma luteinizing hormone and testosterone concentrations and semen quality in normal and cryptorchid dogs during sexual maturation.

Changes in peripheral plasma luteinizing hormone (LH) and testosterone (T) concentrations and semen quality were investigated in four unilaterally cryptorchid (UC), three bilaterally cryptorchid (BC), and five normal beagles, from 4 to 48 weeks of age. Blood samples were collected at 2- or 4-week intervals, and the LH and T concentrations were determined by radioimmunoassay. Semen samples were collected weekly by digital manipulation. The mean LH and T concentrations in the normal dogs increased after 20 and 22 weeks of age and reached approximately 4 ng/ml and 3 ng/ml respectively at 36 weeks of age. Semen volume and total spermatozoa count increased apparently at 34 and 35 weeks of age respectively. Spermatozoa motility and percentage of abnormal spermatozoa varied less after 38 weeks of age. Plasma LH and T concentrations in the UC and BC dogs had a tendency to remain lower than values in the normal dogs after 26 weeks of age. The semen volume and spermatozoa count in the UC dogs did not increase markedly. The spermatozoa count was less than half that in normal dogs, and the percentage of abnormal spermatozoa was higher throughout the experimental period. All BC dogs had azoospermia. Thus it was evident that development of spermatogenic function during sexual maturation in the UC and BC dogs was insufficient compared with that in normal dogs.

Animals↗
PubMed1995

Comparison of the effects of chlormadinone acetate-pellet implantation and orchidectomy on benign prostatic hypertrophy in the dog.

Five beagles out of 11 dogs aged 7-10 years with benign prostatic hypertrophy (BPH) were implanted subcutaneously with pellets of the synthetic anti-androgen chlormadinone acetate (CMA) at a dose of 10 mg/kg bodyweight. The remaining six dogs (one beagle and five mongrel dogs) underwent bilateral orchidectomy. Changes in prostatic volume, histological findings in the prostate and the testis, and peripheral plasma levels of LH, testosterone and oestradiol-17 beta (E2) were assessed up until 24 and 4 weeks after CMA-implantation and orchidectomy, respectively. Measurements of the size of the prostate and biopsies of the prostate were performed by laparotomy. Mean prostatic volume had decreased to 71% and 41%, respectively, of its pretreatment volume, by 4 weeks after CMA-implantation and orchidectomy, and was 49% and 47%, respectively, of pretreatment volume at 12 and 24 weeks after CMA-implantation. The clinical signs of BPH, e.g. haematuria, resolved within 2 weeks after either treatment. When the prostate was examined histologically 4 weeks after either treatment, hardly any evidence of active secretion (e.g. glandular epithelium projecting markedly into the lumen), was observed in CMA-implanted dogs, alveolar diameter and height of the glandular epithelium had decreased markedly and the glandular lumen had become very small in the orchidectomized dogs. By 12 weeks after CMA-implantation, degenerative and atrophic glands were observed in the prostate nearly the same as at 4 weeks after orchidectomy. In the testis the number of germ cells in the seminiferous tubules decreased markedly after CMA-implantation. The mean level of plasma LH at 4 weeks after orchidectomy had increased to 14.9 ng/ml, twice the value before operation. The mean levels of plasma testosterone and E2 at 4 weeks after CMA-implantation had decreased to 0.7 ng/ml and 9 pg/ml from 1.5 ng/ml and 15 pg/ml, the values before treatment, respectively. CMA-implantation resulted in poor semen quality. The results indicate that CMA-implantation at a dose of 10 mg/kg results in the same prostate-shrinking effect as orchidectomy.

Animals↗
PubMed1994

Response of sows to estradiol benzoate after weaning.

Estradiol benzoate (E2B) was intramuscularly injected in 3 groups of weaned sows at a dose of 0.2 mg/head on day 0 and on day 2 and at a dose of 0.4 mg/head on day 2, respectively. The blood concentration of LH rose to a peak 60-66 hr after E2B injection. The rates of the occurrence of estrus after E2B treatment in these groups were 85.7, 89.5 and 87.5%, respectively, with no significant differences compared to the control except for the second group. The farrowing rates in the 3 treated groups were 100, 86.8 and 61.9%, respectively, and the value in the third group was significantly lower compared to the control (p < 0.05). There were no significant differences in average litter size between the control and any of the treated groups.

Animals↗
PubMed1993

Comparison of a fluoresceinated lectin stain with triple staining for evaluating acrosome reactions of dog sperm.

In this study a technique which utilized a fluoresceinated lectin and a fluorescent supravital stain was compared with the conventional triple stain technique for evaluating the viability and acrosomal status of dog sperm. Ten semen samples obtained from 6 normal beagle dogs were evaluated after incubation in vitro with canine capacitation medium. Sperm viability and acrosomal status were assessed at 0, 4, and 7 hours of incubation. Both staining techniques were capable of detecting the increase in spontaneous acrosome reactions which occurs during in vitro capacitation of dog sperm. High positive correlations were observed between the fluorescent stain and the triple stain in the mean values for the percentage of viable sperm and for the percentage of acrosome-reacted sperm among the viable sperm (r = 0.91, r = 0.97, respectively). However, the fluorescent staining techniques could be carried out much more rapidly than the triple stain technique, and the slides prepared with fluorescent stain were more easily scored because of the higher intensity and greater consistency of staining. These characteristics make the fluoresceinated lectin and the fluorescent supravital stain superior for evaluating acrosome reactions and viability of dog sperm.

Acrosome↗
PubMed1993

Induction of acrosome reactions of canine sperm by homologous zona pellucida.

In this study the induction of the acrosome reaction of canine sperm by homologous zona pellucida (ZP) was examined. Twelve semen samples obtained from 6 normal beagle dogs were evaluated after sperm incubation in vitro with canine capacitation medium (CCM). Washed sperm were preincubated at 37 degrees C in 5% CO2 in air for 4 and 7 h prior to experimental treatment. Sperm were co-incubated for 1 min with intact oocytes collected from canine ovaries. Half of the oocytes were then fixed, and the bound sperm were assessed for acrosome reactions through use of a polyclonal antisperm antiserum and indirect immunofluorescence. The remaining oocytes were incubated in sperm-free medium for an additional 1-h period, and the acrosomal status of sperm bound to the ZP was evaluated similarly. The percentage of acrosome-reacted sperm on the ZP increased significantly during the 1-h incubation period. In other experiments, capacitated canine sperm were incubated with heat-solubilized ZP for 1 h and their acrosomal status was determined using fluoresceinated Pisum sativum lectin. The percentages of acrosome-reacted sperm increased significantly in ZP solution compared with controls. These data demonstrate that intact and solubilized canine ZP are capable of inducing acrosome reactions of canine sperm.

Acrosome↗
PubMed1993

Pituitary response of cryptorchid dogs to LH-RH-analogue before and after sexual maturation.

An LH-RH-analogue (LH-RH-A) was administered to 5 cryptorchid (CR) and 6 normal beagles before and after sexual maturation and peripheral plasma LH and testosterone levels were measured. The response patterns of plasma LH levels for LH-RH-A in the CR dogs were similar to those in the normal dogs before and after sexual maturation. It was therefore demonstrated there is little difference in pituitary response to LH-RH-A in the CR and normal dogs. However, the maximum levels of testosterone in the CR dogs were generally lower than those in the normal dogs.

Animals↗
PubMed1993

Ovarian response to hCG in the postweaning sow.

Five non-cyclic postweaning sows were given intramuscularly 1,000 IU of hCG on day 2 (4 sows) and day 36 (1 sow) after weaning. Single or multiple follicular cysts were developed in ovaries in all cases. Plasma E2 fluctuated at low levels in 4 of 5 sows resulting in silent heat. The sows which exhibited neither estrus nor ovulation after hCG administration did not display any preovulatory LH surge, and plasma progesterone levels remained low (< or = 1 ng/ml). These results suggest that abnormal follicular growth or impairment of the ovulation process as a consequence of unsatisfactory LH release after hCG treatment in swine with ovarian inactivity may promote the formation of ovarian cysts.

Animals↗
PubMed1993

Effects of oral administration of chlormadinone acetate on canine prostatic hypertrophy.

Seven of the 25 dogs (4 to 15 years old) with benign prostatic hypertrophy (BPH) at the teaching hospital of Nippon Veterinary and Animal Science University from 1989 through 1990 were treated orally with chlormadinone acetate (CMA), a synthetic anti-androgen, 2 mg/kg/day, twice a day for 3 or 4 weeks. Prostatic size was measured by radiography and ultrasonography before and after CMA treatment, and prostatic volume was calculated from the images. Semen quality was examined in 3 of the dogs with BPH. Peripheral blood samples were collected and plasma levels of LH, 4-androstenedione, 5 alpha-dihydrotestosterone, testosterone and estradiol-17 beta were measured. Clinical signs disappeared within 10 days after the start of CMA treatment. The mean (+/- S.E.) prostatic volume 3 or 4 weeks after treatment decreased to 39 +/- 4% of the pretreatment volume. The mean level of plasma testosterone in the dogs with BPH before treatment was significantly lower than that in the normal dogs (P < 0.01). In 6 of the CMA-treated dogs the levels of all hormones examined, except LH, were significantly lower after CMA treatment than before (P < 0.05). The sperm count and motility decreased and the percentage of abnormal sperms increased after CMA treatment. These results demonstrate that, although CMA treatment in dogs with BPH inhibits testicular function, the prostatic volume is markedly reduced and clinical signs disappear in a short period after the therapy. However, a relapse of BPH was observed approximately 6 months after oral CMA treatment in some dogs.

Administration, Oral↗
PubMed1993

Changes in plasma androgen levels and testicular histology with descent of the testis in the dog.

Levels of 4-androstenedione (A), 5 alpha-dihydrotestosterone (DHT) and testosterone (T) in plasma collected from the heart or the jugular vein were measured in 61 male fetal dogs at between 38 and 60 days of gestation and 55 male neonatal dogs at between 0 and 50 days after birth. Testicular descent and histology were investigated after euthanasia of the fetuses and neonates. Although the testis still lay on the caudal ridge of the kidney in the 38- and 40-day-old fetuses, the gonad had slightly migrated from the kidney by 42 days of gestation. The testis approached the internal inguinal ring at Day 0 after birth and had passed through the inguinal canal at Day 5 after birth. The inguinal passage was the active phase of testicular descent. Both testes were drawn into the scrotum after 35 days of age. The number of gonocytes in the seminiferous cords had increased in the 58-day-old fetus, and Leydig cells in the stroma had become obvious because of morphological development and the formation of cell clumps. Plasma A levels in the male fetuses decreased temporarily after birth and plasma DHT increased provisionally at 54 and 58 days of gestation. Plasma T levels in the male neonates increased markedly after birth. These findings suggest that testicular descent in the dog fetus is accelerated by the DHT and T secretory function of the Leydig cells which increased after 54 days of gestation.

Aging↗
PubMed1991

Effects of LHRH-analogue treatment of spermatogenic dysfunction in the dog.

Three male dogs, aged 2-4 years, which exhibited a high percentage of sperm with abnormal tails in their semen and low levels of peripheral plasma LH and testosterone were given two injections of 400 micrograms an LHRH analogue (LHRH-A) 3 h apart. The semen quality of all three dogs and the peripheral plasma levels of LH and testosterone were examined in two of the dogs. Plasma levels of LH and testosterone in both dogs peaked at 30 and 90 min respectively, after the injection of LHRH-A. The semen quality of all three dogs had improved temporarily 20 days after the injection. To be specific, although the mean percentage of sperm with abnormal tails in the three dogs was 19, 26 and 32% respectively before injection of LHRH-A, these values had decreased to 10, 16 and 13%, respectively, 20-40 days later. Thereafter, however, the percentage sperm abnormalities increased again. The testes and epididymides of two of the dogs were examined histologically at the end of 90 days. Sloughed germ cells were observed in the seminiferous tubules of the testes, and pyknotic epithelial cells were noted in some of the epididymal ducts. The other dog, which had a history of three unsuccessful matings was treated again with LHRH-A and mated with three bitches 30, 75, and 110 days later, respectively. Only the bitch mated with this dog 30 days after a second series of injections conceived. It is assumed that the semen quality of the three dogs improved because of a temporary rise in plasma LH and testosterone levels after the injection of LHRH-A. It is concluded that the fertility of dogs with a high percentage of sperm with abnormal tails can be improved approximately 30 days after treatment with an LHRH-A.

Animals↗
PubMed1991

Response of the lactating and postweaning sow to gonadotropin releasing hormone (GnRH).

Clinical and endocrinological responses to administration of gonadotropin releasing hormone analog (LH-RH-A) during the lactation period and postweaning in the sow were investigated. Plasma LH concentrations in lactating sows rose immediately after administration of LH-RH-A. However, in postweaning sows the increase of LH level was more slowly. Three of 5 postweaning sows came into estrus and ovulated after LH-RH-A treatment. One sow exhibited a distinct LH response, but her ovaries remained quiescent. The remaining one with feeble estrus for a short period became cystic ovaries. Thus, LH response to GnRH in the sow seems to be higher during early lactation than at 2 days postweaning.

Animals↗
PubMed1991

Histological observations of the reproductive organs of the male dog from birth to sexual maturity.

Development of the testis, epididymis and prostate in 53 male beagles was examined histologically with PAS-hematoxylin stain from birth to sexual maturity. The diameter of the seminiferous tubules of the testes was less than 100 microns until 20 weeks of age, however, it increased markedly between 22 and 28 week of age, reaching 180 +/- 7 (mean +/- SD) microns at 28 weeks of age. Only Sertoli cells and gonocytes (or spermatogonia) were detected in the seminiferous tubules until 16 weeks of age. Spermatocytes and spermatids appeared in the tubules at 20 and 22 weeks of age, respectively. Spermatozoa were first observed in the testes of 2 of the 5 dogs at 26 weeks of age and were found in the testes of all the 3 dogs at 28 weeks of age. The diameter of the ducts in the cauda epididymidis was 146 +/- 4 microns at 20 weeks of age. Thereafter it increased markedly, reaching 341 +/- 14 microns at 28 weeks of age. The height of the epithelium and stereocilia in the ducts of the caput epididymidis increased markedly at about 28 weeks of age. A large number of spermatozoa was seen in the lumens of the ducts of the corpus and cauda epididymidis after 32 weeks of age. The shape of the lumens in the glandular alveoli of the prostate became irregular as a result of projection of the glandular epithelium into the enlarged lumens and the epithelial cells of the alveoli became PAS-positive at 24 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Hyperactivation and acrosome reaction in vitro in spermatozoa ejaculated by cryptorchid dogs after orchiopexy.

Orchiopexy of the cryptorchid (CR) testis and castration of the scrotal testis were performed in three unilaterally CR beagles at six months of age. Induction rates for ejaculated sperm hyperactivation (HA) and the acrosome reaction (AR) in vitro in these orchiopexied dogs were compared with five those in normal beagles one year later. Canine spermatozoa were incubated for 9 hr at 38 degrees C under 5% CO2 in air in canine capacitation medium at a concentration of 30 x 10(6) sperm/ml. HA was observed using high-speed videomicrography. The AR spermatozoa were evaluated by the triple stain technique. As a result, there was no significant difference between 'the CR dogs after orchiopexy' (CDO) and the normal dogs (ND) with respect to sperm motility just after ejaculation. However, sperm motility of CDO decreased markedly during incubation. There was a significant difference in sperm motility between CDO (Mean +/- SD; 47 +/- 12%) and ND (80 +/- 9%) after three hours of incubation (p less than 0.01). No significant difference was observed between CDO and ND with respect to the HA rate of motile spermatozoa throughout the incubation period. The peak of HA rate was found in both CDO (58 +/- 5%) and ND (61 +/- 16%) after seven hours of incubation. The AR rate of spermatozoa in CDO was lower than that in ND after six hours of incubation. The AR rate of CDO (26 +/- 4%) was significantly lower than ND (46 +/- 5%) after eight hours of incubation (p less than 0.01). It is assumed that there might be relation between a rapid decrease of motility and low AR rate in spermatozoa of CDO during incubation.

Acrosome↗
PubMed1990

Androgen concentration in the blood and spermatogenic function of tom cats during the breeding season.

In order to better understand androgen secretion in the tom cat during the breeding season, observations of diurnal changes in peripheral blood testosterone (T) levels, were made and the relation between androgen levels (androstenedione (A), 5 alpha-dihydrotestosterone (DHT). T) in testicular and peripheral vein blood was borne. Histologic examinations of the testis were also performed to investigate spermatogenic function. The 9 tom cats used in these studies were 2-3 years old, weighed 3.5-4.0 kg, and were raised in a room under natural lighting. As a result, diurnal peripheral blood T levels in the tom cat fluctuated greatly according to each individual, but since no definite trend could be identified, secretion was determined to be episodic. Although fairly large differences in the 3 types of androgen were observed in testicular vein blood depending on the individual animal, levels on the left and right were almost equal. Moreover, a correlation was found between the testicular and peripheral vein blood concentrations of the 3 androgens (A: p less than 0.01; DHT: p less than 0.05; T: p less than 0.01). Therefore, secretion of testicular androgen can be inferred by measuring peripheral blood androgen levels. Testicular histological examination revealed active spermatogenesis in all of the cats, and no significant inter individual differences were detected in either seminiferous tubule diameters or any of the various germ cells.

Androstenedione↗