Postoperative Cognitive Dysfunction in Indian Patients Undergoing Total Knee Replacement Under Spinal Anesthesia.

INTRODUCTION: Total knee replacement is a common surgical procedure in the elderly. The number of surgeries has increased owing to the increasing life expectancy of the population and better functional outcomes postsurgery. Postoperative cognitive dysfunction (POCD) is an identified entity postsurgery in elderly but most of the studies have been on patients undergoing cardiac and other nonorthopaedic surgeries. The studies have shown variable incidence due to selection bias. We studied the incidence and probable predictive factors of POCD in elderly Indian population undergoing total knee replacement under spinal anesthesia. MATERIALS AND METHODS: We designed a prospective, observational study at a single center including patients above 60 years of age undergoing total knee replacement under spinal anesthesia. Preoperative mini-mental scale examination, electrolytes, urea and creatinine levels were recorded. Postoperatively, mini mental scale evaluation (MMSE) was done 2 days postsurgery, at 3 months, 6 months, and 1 year follow-up. Laboratory values postoperatively were recorded. RESULTS: The average preoperative MMSE was 27 and declined to 25.4 on second postoperative day the value increased to 25.9, 26.6, and 27 at 3 months, 6 months, and 1-year follow-up, respectively. Sixty-three out of 600 patients developed POCD at second postoperative day. Forty-three patients showed recovery in subsequent visits and 20 patients had persistent dysfunction at the end of 1 year. Electrolyte imbalance, oxygen saturation, and age over 80 years were factors that showed statistically significant difference in multiple comparison analysis. CONCLUSION: In our study, we have found POCD to be a definitive entity which can cause short- and long-term cognitive defect in elderly Indian population undergoing total knee replacement and electrolyte imbalance, age, and oxygen saturation were the significant factors in the patients who developed POCD.

Bsu2413I and Bfi2411I, two new thermophilic type II restriction endonucleases from Bacillus subtilis and Bacillus firmus: isolation and partial purification. Thermophilic endonucleases from two Bacillus species.

Two new thermophilic type II restriction endonucleases, which we designated as Bsu2413I and Bfi2411I, have been isolated from gram-positive thermophilic bacteria Bacillus subtilis strain 2413 and Bacillus firmus strain 2411 respectively and partially purified. The restriction endonucleases were extracted from cell extracts and purified using single step purification through phosphocellulose column chromatography. SDS-PAGE profile showed denatured molecular weights of 33 and 67 kDa for the Bsu2413I and 39 and 67 kDa for the Bfi2411I. The partially purified Bsu2413I enzyme restricted pBR322 DNA into two fragments of 3250 and 1100 bp whereas Bfi2411I enzyme restricted pBR322 DNA into two fragments of 3500 and 800 bp. The activity of both endonucleases was assayed at 55 degrees C and they required Mg+2 as cofactor like other type II restriction endonucleases.

Isolation and partial purification of a novel type II restriction endonuclease Bsu121 I, from Bacillus subtilis. Bsu121I, a type II restriction endonuclease from Bacillus subtilis.

A new type II restriction endonuclease which we designated as Bsu121I has been isolated from gram-positive bacterium Bacillus subtilis strain 121 and partially purified. The restriction endonuclease was isolated from cell extracts using step-wise purification through ammonium sulfate precipitation, followed by phosphocellulose column chromatography. SDS-PAGE profile showed denatured molecular weights (23 and 67 kDa) of the endonuclease. The partially purified enzyme restricted pBR322 DNA into two fragments of 3200 and 1700 bp. The endonuclease activity required Mg(+2) as cofactor like other type II endonucleases.