Deficient fumarase activity in an infant with fumaricacidemia and its distribution between the different forms of the enzyme seen on isoelectric focusing.

A male infant, whose parents were first cousins, presented at 6 mo of age with hypotonia, microcephaly, and delayed development. He was found to have large amounts of fumaric and succinic acids present in the urine. In lysed cultured skin-fibroblast preparations, the activity of fumarase was found to be 22.7% of that in controls. Cell fractionation by homogenization and by digitonin treatment indicated that the residual activity in the cells of the patient was primarily located in the mitochondrial fraction rather than in the cytosolic fraction. Isoelectric focusing of fibroblast extracts showed that six bands of fumarase activity were discernible in control cell lines, two of them cytosolic with pI's of 5.53 and 5.60 and four of them mitochondrial with a pI of 5.65-6.8. In contrast, isoelectric focusing of fibroblast extracts from the fumarase-deficient patient showed only a single band of activity with a pI corresponding to the mitochondrial type seen in the controls. Immunoprecipitation of proteins with rabbit antifumarase antibody in (35S)-methionine-labeled fibroblasts indicated that a protein of correct size (Mr = 44,000 daltons) corresponding to fumarase was synthesized in similar amounts in both the patients and controls. It is proposed that in the patient's cells a single active species of fumarase that is mitochondrial in location is synthesized. Since it is known that mitochondrial and cytosolic fumarases are encoded by the same gene but differ slightly in amino acid sequence, it is possible that a point mutation might explain these findings.     

Home range use and the exploitation of gum in the marmosetCallithrix jacchus jacchus

Three wild groups of common marmoset, Callithrix jacchus jacchus,in north-east Brazil, of approximately similar size, had home ranges between 2.5 and 6.5 ha. But their core areas were similar in size between 1.0 and 1.5 ha, with a monthly area of heavy use between 1.1 and 1.6 ha. The groups were selective in the use of their home ranges, even though they were small: they used some areas heavily and others lightly. The core areas had higher densities of trees that produced gum exudates than did other parts of the home ranges. Our data suggest that a group of marmosets in this habitat may require a minimum of about 50 gum trees in its home range at a minimum density of about 50 trees/ha. In addition, the animals require suitable trees in which to sleep. We suggest that patches of forest with these desirable properties remain relatively fixed in size and location over the years and that individual animals are constantly in flux between them.     

Microscopic visualization of insect cell-bubble interactions. I: Rising bubbles, air-medium interface, and the foam layer.

Through the use of microscopic, high-speed video technology, the interactions of two suspended insect cell lines, Trichoplusia ni (TN-368) and Spodoptera frugiperda (SF-9), with air and oxygen bubbles were studied. Events such as cell-bubble attachment, cell-bubble collision, cell transport into the foam layer, and trapping of cells in the foam layer are presented and discussed. Based on these observations and those in a companion paper (Chalmers, J. J.; Bavarian, F. Biotechnol. Prog. 1991, following paper in this issue) and the experimental and theoretical work of other researchers, several mechanisms of cell damage as a result of sparging are presented.     

Reducing the incidence of infection after caesarean section: implications of prophylaxis with antibiotics for hospital resources.

OBJECTIVES--To estimate the cost effectiveness of giving prophylactic antibiotics routinely to reduce the incidence of wound infection after caesarean section. DESIGN--Estimation of cost effectiveness was based, firstly, on a retrospective overview of 58 controlled trials and, secondly, on evidence about costs derived from data and observations of practice. SETTING--Trials included in the overview were from obstetric units in several different countries, including the United Kingdom. The costing study was based on data referring to the John Radcliffe Maternity Hospital, Oxford. SUBJECTS--A total of 7777 women were included in the 58 controlled trials comparing the effects of giving routine prophylactic antibiotics at caesarean section with either treatment with a placebo or no treatment. Cost estimates were based on data on 486 women who had caesarean sections between January and September 1987. MAIN OUTCOME MEASURE--Cost effectiveness of prophylaxis with antibiotics. RESULTS--The odds of wound infection are likely to be reduced by between about 50 and 70% by giving antibiotics routinely at caesarean section. Forty one (8.4%) women who had caesarean section were coded by the Oxford obstetric data system as having developed wound infection. The additional average cost of hospital postnatal care for women with wound infection (compared with women who had had caesarean section and no wound infection) was estimated to be 716 pounds; introducing routine prophylaxis with antibiotics would reduce average costs of postnatal care by between 1300 pounds and 3900/100 pounds caesarean sections (at 1988 prices), depending on the cost of the antibiotic used and its effectiveness. CONCLUSIONS--The results suggest that giving antibiotics routinely at caesarean section will not only reduce rates of infection after caesarean section but also reduce costs.     

A Fourier-transform infrared spectroscopic analysis of organic matter degradation in a bench-scale solid substrate fermentation (composting) system

The degradation of organic matter was evaluated by a quantitative Fourier transform infrared spectroscopy (FTIR) analysis technique. The degradation process was conducted in a bench-scale reactor under controlled operational conditions of 50 degrees C, with 50-60% moisture content, and subjected to uniform aeration for 325 h. During the composting process, ATP concentration increased from 0.1 to 8 mug/g and the maximum CO(2) evolution and O(2) consumption rates reached 0.04 and 0.085 mmol/g-h, respectively. Polysaccharide content decreased approximately 50% while lignin content remained unchanged. Three regions of the FTIR spectra were used for quantification: 1070-974, 1705-1614, and 2995-2887 cm(-1), which correspond to polysaccharides and aromatic and aliphatic compounds, respectively. The actual spectra quantification consisted of peak identification using a second derivative and curve fitting technique, followed by normalization using the internal standard CaCO(3). The results obtained with the spectra quantification technique was then compared to commonly used wet chemistry extraction procedures. Reasonable correlation between the two techniques was obtained. (c) 1996 John Wiley & Sons, Inc.     

Study of hydrodynamics in microcarrier culture spinner vessels: A particle tracking velocimetry approach

Three-dimensional particle tracking velocimetry (3-D PTV), a modern, quantitative, visualization tool, has been applied to the characterization of the flow field in the impeller region of cell culture reactor vessels. The experimental system used here is a 250-mL microcarrier spinner vessel. The studies were conducted at three different agitation rates, 90, 150, and 210 rpm, corresponding to healthy, mildly damaging, and severely damaging shear intensities, respectively. The flow can be classified into three regions: a predominantly tangential (azimuthal) flow generated by the impeller; a trailing vortex region coming off the impeller tip; and a converging flow region close to the center of the vessel. The latter two are the regions of highest velocity gradients. Energy dissipation rates due to mean velocity gradients were also calculated to characterize the impeller stream. Local specific energy dissipation rates > 10,000 erg/(cm(3)sec) . have been measured. It is proposed that the critical regions for microcarrier culture damage due to impeller hydrodynamics are the trailing vortex region and the high energy converging flow region. Graphical representation of the mean velocity flow fields and the distribution of energy dissipation rates in the impeller region are also presented here. The merits of using the dissipation function (measure of specific energy dissipation rate) as a possible scale-up parameter are also discussed. (c) 1996 John Wiley & Sons, Inc.     

Big flies, small repeats: the "Thr-Gly" region of the period gene in Diptera

The region of the clock gene period (per) that encodes a repetitive tract of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran species both within and outside the Drosophilidae. All the non- Drosophilidae sequences in this region are short and present a remarkably stable picture compared to the Drosophilidae, in which the region is much larger and extremely variable, both in size and composition. The accelerated evolution in the repetitive region of the Drosophilidae appears to be mainly due to an expansion of two ancestral repeats, one encoding a Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and asparagine or threonine. In some drosophilids the expansion involves a duplication of the pentapeptide sequence, but in Drosophila pseudoobscura both the dipeptide and the pentapeptide repeats are present in larger numbers. In the nondrosophilids, however, the pentapeptide sequence is represented by one copy and the dipeptide by two copies. These observations fulfill some of the predictions of recent theoretical models that have simulated the evolution of repetitive sequences.      

Genomic organization of GB viruses A and B: two new members of the Flaviviridae associated with GB agent hepatitis.

The genomes of two positive-strand RNA viruses have recently been cloned from the serum of a GB agent-infected tamarin by using representational difference analysis. The two agent, GB viruses A and B (GBV-A and GBV-B, respectively), have genomes of 9,493 and 9,143 nucleotides, respectively, and single large open reading frames that encode potential polyprotein precursors of 2,972 and 2,864 amino acids, respectively. The genomes of these agents are organized much like those of other pestiviruses and flaviviruses, with genes predicted to encode structural and nonstructural proteins located at the 5' and 3' ends, respectively. Amino acid sequence alignments and subsequent phylogenetic analysis of the RNA-dependent RNA polymerases (RdRps) of GBV-A and GBV-B show that they possess conserved sequence motifs associated with supergroup II RNA polymerases of positive-strand RNA viruses. On the basis of similar analyses, the GBV-A- and GBV-B-encoded helicases show significant identity with the supergroup II helicases of positive-strand RNA viruses. Within the supergroup II RNA polymerases and helicases, GBV-A and GBV-B are most closely related to the hepatitis C virus group. Across their entire open reading frames, the GB agents exhibit 27% amino sequence identity to each other, approximately 28% identity to hepatitis C virus type 1, and approximately 20% identity to either bovine viral diarrhea virus or yellow fever virus. The degree of sequence divergence between GBV-A and GBV-B and other Flaviviridae members demonstrates that the GB agents are representatives of two new genera within the Flaviviridae family.     

Planned and unplanned deliveries at home: implications of a changing ratio.

The observation that perinatal mortality among babies delivered at home has tended to increase beyond that among babies delivered in consultant obstetric units has caused alarm and prompted recommendations that delivery at home should be further phased out. With data derived from the Cardiff Births Survey the possibility was investigated that this trend might reflect a changing ratio of planned to unplanned domiciliary births. At the beginning of the 1970s deliveries at home that were planned to be so outnumbered those that were not by nearly five to one. By 1979 unplanned deliveries at home outnumbered planned deliveries. The characteristics of the mothers, the health care they received, and the outcome of delivery differed strikingly between planned and unplanned deliveries at home. It is concluded, firstly, that every year the maternity services must try to meet the various needs of about 2000 women in England and Wales who give birth at home without planning to do so; and, secondly, that the heterogeneity of births at home and in hospital will continue to obstruct the search for unbiased estimates of the risks attributable to delivery in specialist obstetric units, general practitioner units, and at home.