[Obtaining homogenous preparations of succinate dehydrogenase isoforms from the D-507 strain of Sphaerotilus natans].

Enzymatic preparations of two isoforms of succinate dehydrogenase (SDG) with specific activity of 22.00 E/mg of protein were obtained from the colorless sulfur bacterium Sphaerotilus natans D-507 cultured organotrophically. Both SDG forms were shown to be heteromers with subunit molecular masses of 70.8, 35.0, 31.8, and 16.2 kDa. The K(m) values for the first and the second forms of SDG were evaluated as 0.615 and 0.531 mM, respectively, with an optimal pH value of 7.2. It was found that the Cl- ion has an activating effect on the SDG activity that can be explained by the specific chemical modification of the enzyme molecule. The results suggest that the isolated enzyme forms are included in different multienzyme complexes, which provide the functioning of the tricarboxylic acid cycle, and SDG preparations can be used for the investigation of other enzyme systems or in vitro modeling of supramolecular cellular structures.

Long-term outcomes of patients with Streptococcus suis infection in Viet Nam: A case-control study.

OBJECTIVES: Streptococcus suis is a zoonotic cause of severe meningitis and sepsis in humans. We aimed to assess the long-term outcomes in patients who survived S. suis infection, in particular the progress and impact of vestibulocochlear sequelae. METHODS: This case-control study evaluated outcomes of S. suis infection at discharge and 3 and 9 months post-discharge for 47 prospectively enrolled cases and at 11-34 months for 31 retrospectively enrolled cases. Outcomes in patients were compared to 270 controls matched for age, sex and residency. RESULTS: The prevalence ratio (PR) of moderate-to-complete hearing loss was 5.0(95%CI 3.6-7.1) in cases at discharge, 3.7(2.5-5.4) at 3 months, 3.2(2.2-4.7) at 9 months, and 3.1(2.1-4.4) in retrospective cases compared to controls. Hearing improvement occurred mostly within the first 3 months with a change in hearing level of 11.1%(95%CI 7.0-15.1%) compared to discharge. The PR of vestibular dysfunction was 2.4(95%CI 1.7-3.3) at discharge, 2.2(1.4-3.1) at 3 months, 1.8(1.1-2.5) at 9 months, and 1.8(1.1-2.6) for retrospective cases compared to controls. Cases also indicated more problems with mobility, self-care and usual activities. CONCLUSIONS: Both hearing and vestibular impairment were common and persist in cases. Appropriate patient management strategies are needed to reduce the incidence and impact of these sequelae.

Fetal blood and tissue PO2 during maternal oxygen breathing.

The effect of 100% oxygen breathing on fetal blood and tissue PO2 was examined in chronically catheterised fetal sheep of 12 pregnant ewes. Blood PO2 was monitored with intravascular polarographic electrodes and tissue PO2 with galvanic electrodes implanted in various tissues. In non-acidotic healthy fetuses, oxygen breathing increased fetal PO2 by 30% within 3 min in arterial blood and within 5 min in tissues. Thereafter blood PO2 increased by a maximum of 40% at 9 min and tissue PO2 rose by a maximum of 52% at 12 min. Blood PO2 returned promptly to control values after 15 min of oxygen breathing but washout of oxygen from tissues was slower and tissue PO2 remained significantly higher in the post-oxygen versus the pre-oxygen period. Continuation of oxygen breathing for 30 min did not lead to any further increase in tissue PO2. Oxygen breathing did not prevent a decrease in fetal PO2 associated with spontaneous myoelectrical activity of the uterus. It is concluded that maternal oxygen breathing leads to a significant increase in both blood and tissue PO2 in the healthy fetus. The majority of the increase occurs within the first 3-4 min and no further increase in either blood or tissue PO2 is observed after 12 min.