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K Konnai

Publications and source records attributed to K Konnai.

4 recordsLinked to original sources
PubMed1999

The usefulness of a piezo-micromanipulator in intracytoplasmic sperm injection in humans.

Intracytoplasmic sperm injection (ICSI) has wide clinical application. In order to achieve good results with this method, it is important to restrict the possibility of oocyte injury as much as possible, and securely inject spermatozoa into the ooplasm. For this purpose, we clinically applied piezo-ICSI, which employs a micromanipulator with piezoelectric elements, to humans, and compared the results with those obtained by conventional ICSI. Conventional ICSI and piezo-ICSI were used in 279 cycles and 335 cycles respectively. Piezo-ICSI showed significantly more favourable results, with a survival rate of 88.1% (conventional ICSI: 81.4, P < 0.001), a fertilization rate of 79.4% (conventional ICSI: 66.4%, P < 0.001), and a pregnancy rate of 23.1% (conventional ICSI: 14.9%, P < 0.05). In piezo-ICSI, the needle used is not sharpened and has a flat tip. However, deformation of the oocyte during insertion of the needle is restrained by vibration of the piezo, and the oolemma is punctured readily and securely by the piezo pulse, at the site where the spermatozoon is injected. Piezo-ICSI is a promising new technique for human ICSI that should improve the survival, fertilization and pregnancy rates after ICSI.

Adult↗
PubMed1997

Fertilization using male germ line-cells.

In recent years, favorable results have been achieved in patients suffering from azoospermia by microinsemination of spermatozoa taken from their testes. Microinsemination is being introduced in the treatment of patients who have no spermatozoa in their testes via their spermatid and spermatocyte. There are still doubts relating to immature male germ line-cells, such as whether they have, oocyte activating factors, the level of stability of DNA of cell nuclei, and the differences in chromosome numbers. The relatively few cases of gestation using the human spermatid treatment may be due to embryological problems resulting from the instability of nuclear DNA and the insufficiency of oocyte activating factors, which are the result of imperfect microinjection techniques. Improvements in techniques for the clinical application of spermatid and secondary spermatocyte, as well as the collection of basic data to confirm embryological safety are therefore necessary.

Animals↗
PubMedDate not supplied

Clinical evaluation of squamous cell carcinoma antigen in squamous cell carcinoma arising in mature cystic teratoma of the ovary.

We attempted to assess the clinical utility of squamous cell carcinoma antigen (SCC) for detecting squamous cell carcinoma arising in mature cystic teratoma of the ovary. SCC in serum from 16 patients with this malignancy and from 56 patients with mature cystic teratoma without malignancy was measured using radioimmunoassay. Serum SCC levels exceeded the cut-off of 2.0 ng/ml in 9 (56%) of the 16 patients with malignancy. This rate was significantly higher than that in the patients with nonmalignant mature cystic teratoma (9 to 56, 16%; p < 0.01). The positive rate for SCC was as low as 30% for stage I cancer. All cases in which the tumor size was > 500 cm3 had a positive response for SCC, whereas all other cases had a negative response (p < 0.001). SCC is useful as a tumor marker for this malignancy. However, the serum SCC level depends on the tumor volume, so it may not be suitable for early detection of small tumors.

Adolescent↗