Virus elimination during the recycling of chromatographic columns used during the manufacture of coagulation factors

Various chromatographic procedures are used during the purification and manufacture of plasma products such as coagulation factors. These steps contribute to the overall safety of such products by removing potential virus contamination. Virus removal by two affinity chromatography procedures, i.e. monoclonal antibody chromatography and metal chelate chromatography (immobilised metal ion affinity chromatography), used during the manufacture of the high purity factor VIII (Replenate^®) and factor IX (Replenine^®-VF), respectively, has been investigated. In addition, as these columns are recycled after use, the effectiveness of the sanitisation procedures for preventing possible cross-contamination, has also been investigated.Both chromatographic steps proved effective for eliminating a range of model enveloped and non-enveloped viruses by 4 to >6 and 5 to >8 log for the monoclonal and metal chelate columns, respectively. The effectiveness of the relatively mild column sanitisation conditions used, i.e. ethanol for factor IX and acetic acid for factor VIII, was confirmed using non-spiked column runs. The chemicals used contributed to virus elimination by inactivation and/or by physical removal of the virus. In summary, these studies demonstrate that potential virus contamination between chromatographic runs can be prevented when an effective column recycling and sanitisation procedure is included.     

Retention of episomes during protoplasting and during propagation in the L state

Kawakami, Masaya (Georgetown University, Washington, D.C.), and Otto E. Landman. Retention of episomes during protoplasting and during propagation in the L state. J. Bacteriol. 92:398-404. 1966.-In earlier work, it was observed that the mesosomes of Bacillus magaterium and B. subtilis are expelled from the cell interior during protoplasting and that mesosome fragments are released into the supernatant fluid as the cell wall disintegrates. Since the resultant protoplasts remain intact and capable of reproduction, the expelled contents of the mesosome "bag" are presumably external to the protoplast membrane and nonessential to survival. Accordingly, if episomes (plasmids) were localized in the extramembrane mesosome "bag," it would be predicted that protoplasting would cure cells of their episomes. This prediction was tested in three different systems: B. subtilis W23 carrying phage SP-10, B. megaterium 216 carrying megacinogenic factors A and C, and B. megaterium C4M(-) carrying megacinogenic factor C. No curing due to protoplasting was observed. Even during propagation in the L form, when septation is not functioning and the distribution of deoxyribonucleic acid to daughter cells is severely disrupted, curing was not observed in any of the above systems nor in Salmonella L forms carrying F(0)lac. It is concluded that episomes are located at a position on the interior side of the cell membrane and that their distribution to daughter cells is coordinated with that of the chromosome.     

Perceptions of effort and heaviness during fatigue and during the size-weight illusion

Previous work has shown that force perception and the sense of motor effort are different attributes of sensorimotor function. This study explores the hypothesis that one reason force and effort perceptions are distinct is to inform an individual of impaired motor function when muscular force lags effort. This hypothesis predicts that effort and force perceptions will dissociate when motor function is impaired by fatigue but not during the size-weight illusion. All subjects reported a distinct increase in effort when lifting a standard test weight as fatigue developed. When fatigue was sufficiently marked so that they could barely lift the test weight, they rated their effort as similar to that required to lift a maximal weight in the unfatigued state. The perceived heaviness of the test weight also increased as fatigue developed, but this fatigue-weight illusion was smaller than the increase in effort for all subjects and displayed greater variability. In contrast, both the perceived weight of a small object and the effort required to lift it increased in parallel when small and large objects were lifted sequentially. The size-weight and size-effort illusions appear to be examples of a common phenomenon in which perceptual experience is rescaled to maintain acuity under different working conditions. The fatigue-weight illusion also has the effect of increasing perceptual acuity as the subject's weight lifting range decreases due to fatigue.     

Water balance during vitellogenesis by the American cockroach: translocation of water during the cycle

The female American cockroach undergoes harmonious cycles of ingestion and elimination during the 6-day vitellogenic cycle. More water is lost through transpiration than through faeces, and under dessicating conditions the female cockroach is able to reduce water loss by regulation of transpiration. The use of radioactive water permits a comparison of ‘gross’ and ‘net’ water loss during transpiration.     

LH excretion during the ovulatory cycle and during therapy with various estrogen-gestagen combinations

Immunochemical determination of urinary LH was carried out in 7 normally ovulating women and in 25 women treated with various combined, sequential, and depot hormonal contraceptives. In ovulatory cycles without hormone treatment an LH peak was always observed at midcycle. During treatment with Ovosiston, OZN, and Quinestrol-norethisterone acetate, no LH peak was seen. In women receiving sequential preparations (mestranol-chlormadinone acetate, estrone cyanate-chlormadinone acetate), elevated LH levels were observed during estrogen medication. LH excretion was suppressed after administration of chlormadinone acetate. LH levels were also slightly elevated before and after medication with Quinestrol-chlormadinone acatate (1 pill per month).     

Temperature during the day, but not during the night, controls flowering of Phalaenopsis orchids

Phalaenopsis orchids are among the most valuable potted flowering crops commercially produced throughout the world because of their long flower life and ease of crop scheduling to meet specific market dates. During commercial production, Phalaenopsis are usually grown at an air temperature > or =28 degrees C to inhibit flower initiation, and a cooler night than day temperature regimen (e.g. 25/20 degrees C day/night) is used to induce flowering. However, the specific effect of day and night temperature on flower initiation has not been well described, and the reported requirement for a diurnal temperature fluctuation to elicit flowering is unclear. Two Phalaenopsis clones were grown in glass greenhouse compartments with constant temperature set points of 14, 17, 20, 23, 26, or 29 degrees C and fluctuating day/night (12 h/12 h) temperatures of 20/14, 23/17, 26/14, 26/20, 29/17, or 29/23 degrees C. The photoperiod was 12 h, and the maximum irradiance was controlled to < or =150 micromol m(-2) s(-1). After 20 weeks, > or =80% of plants of both clones had a visible inflorescence when grown at constant 14, 17, 20, or 23 degrees C and at fluctuating day/night temperatures of 20/14 degrees C or 23/17 degrees C. None of the plants were reproductive within 20 weeks when grown at a constant 29 degrees C or at 29/17 degrees C or 29/23 degrees C day/night temperature regimens. The number of inflorescences per plant and the number of flower buds on the first inflorescence were greatest when the average daily temperature was 14 degrees C or 17 degrees C. These results indicate that a day/night fluctuation in temperature is not required for inflorescence initiation in these two Phalaenopsis clones. Furthermore, the inhibition of flowering when the day temperature was 29 degrees C and the night temperature was 17 degrees C or 23 degrees C suggests that a warm day temperature inhibits flower initiation in Phalaenopsis.     

Perceptual-motor performance during the menstrual cycle

Study I: Choice reaction times were measured in 12 normally menstruating women using a numerals-keys serial response task with three set sizes (two, four, and eight). Testing was carried out at four successive phases of the menstrual cycle corresponding with different states of neuroendocrine activity. They were, respectively: (i) 2nd day of flow; (ii) 4th day after cessation of flow (preovulation); (iii) 12th day after flow (postovulation); and (iv) 3rd day before next (estimated) flow. No consistent relationship between performance and phase of the cycle could be demonstrated. The only significant effect was an increase in reaction time with increasing set size. The study provides no support for the theory that variations in estrogen and progesterone levels may cause behaviorally relevant changes in central nervous system functioning. Study II: Four women suffering from premenstrual tension were examined thrice weekly on the same task for 4 consecutive weeks. Three hours prior to testing, a blood sample was drawn and assayed for estrogen, progesterone, and gonadotropin (LH). Performance on the serial choice response task bore no consistent relationship to blood levels of any of the three hormones. Performance before ovulation (as determined by peak LH level) did not differ significantly from that after ovulation. These results concur with those of Study I: there was no reliable relationship between hormonal status and performance.