Effects of alfentanil on the equine electroencephalogram during anaesthesia with halothane in oxygen

Opioids have variable effects on the minimum alveolar concentration of inhaled anaesthetics in the horse. During halothane anaesthesia at an end-tidal halothane concentration between 0.75 and 0.85 percent, the electroencephalogram (EEG) frequency power spectrum and the auditory evoked potential were recorded continuously in eight ponies during an infusion of approximately 40 micrograms kg-1 alfentanil over five minutes, and for a further 55 minutes. The spectral edge and median frequency of the EEG and the mid-latency of the auditory evoked potential at the time of maximum change of these variables were compared with those recorded before the start of the infusion. The mean (SD) spectral edge and median frequencies were reduced by 26 (5) percent and 36 (6) percent respectively. The mid-latency of the auditory evoked potential did not change. These cortical effects of alfentanil in the horse are qualitatively the same as in other species, suggesting that the alfentanil-induced excitement observed in horses in not of cortical origin.

Isolation of cholesterol oxidation products from animal fat using aminopropyl solid-phase extraction

Cholesterol oxidation products were separated from triglycerides and cholesterol in a single step on an aminopropyl solid-phase extraction column. The products were purified by subsequent transesterification and saponification, derivatized to trimethylsilyl ethers and analyzed by gas chromatography. Heated cholesterol-containing fat samples were autoxidized by bubbling air through them. When the flow-rate of air was set at 100 ml/min, the concentration of cholesterol oxidation products in the fat increased to a maximum after 1-2 h and then decreased to almost a zero level after 8 h. The concentration of cholesterol oxidation products in the fat increased over a similar time period, without reaching a maximum, when the flow-rate of air was decreased to 5 ml/min.

Intra-articular morphine and saline injections induce release of large molecular weight proteoglycans into equine synovial fluid

Both morphine and physiologic saline injected intra-articularly into healthy equine tarsocrural joints induced a release of large molecular size proteoglycan (PG) subunits into the synovial fluid (SF) analysed 24 h postinjection. High-performance liquid chromatography (HPLC) with a size-exclusion column was used to assess the high molecular weight proteoglycans in equine synovial fluid (SF). The PG peaks of SF samples eluated separately from SF hyaluronate and other molecular components of the SF in the HPLC chromatographies indicating no interaction between hyaluronate and PG in the SF. Individual elution profiles varied between joints and horses. The amount of PG release was measured by relative area index from the HPLC chromatograms. The synovial fluid PG content was significantly increased (P < 0.05) after morphine but not in saline injected joints compared with pretreatment but there were no significant differences between the two groups. It was concluded that intra-articular injections of both morphine and physiologic saline are able to elicit a marked PG release into the SF from articular cartilage within 24 h of injection.

Evaluation of a modification of the Hudson demand valve in ventilated and spontaneously breathing horses

Hypoxaemia commonly develops during general anaesthesia and in the recovery period in horses. The Hudson demand valve has been used to increase arterial PO2, but it has been found to increase airway resistance considerably when used during spontaneous ventilation. This paper evaluates a modification of the valve designed to reduce this resistance. The effects of the valve and its modification on arterial oxygen (PaO2), and carbon dioxide (PaCO2) tensions were evaluated in four ponies anaesthetised by a total intravenous technique. The valve increased PaO2 from 8.3 +/- 1.1 to 32.7 +/- 7.6 kPa during spontaneous ventilation and to 44.2 +/- 7.4 kPa during intermittent positive pressure ventilation. With the modification, the PaCO2 was increased to 9.0 +/- 2.5 kPa during spontaneous ventilation PaO2 was unchanged by the valve (7.2 +/- 0.4 kPa to 7.1 +/- 0.7 kPa) but it was reduced to 6.4 +/- 0.9 kPa with the modification. The valve was also evaluated in 20 clinical cases during their recovery from halothane anaesthesia. It increased PaO2 from 7.4 +/- 2.1 kPa to 17 +/- 18.3 kPa during spontaneous ventilation and from 8.0 +/- 1.8 kPa to 23.4 +/- 22.2 kPa during positive pressure ventilation. With the modification, PaO2 was increased from 7.8 +/- 1.4 kPa to 10.4 +/- 3.8 kPa during spontaneous ventilation and from 7.6 +/- 1.5 kPa to 14.8 +/- 8.4 kPa during positive pressure ventilation. During spontaneous ventilation PaCO2 was increased from 5.9 +/- 0.4 kPa to 6.2 +/- 0.6 kPa with the unmodified valve and from 6.3 +/- 0.5 kPa to 6.6 +/- 0.5 kPa with the modification.(ABSTRACT TRUNCATED AT 250 WORDS)

Early adoption of cyclosporine and recombinant human erythropoietin: clinical, economic, and policy issues with emergence of high-cost drugs

The discovery of new drugs and their introduction into US markets will become an intense area of focus should health care reform result in Medicare insurance coverage for prescription drugs. Particular attention will be focused on high-cost drugs. Two high-cost drugs, cyclosporine and recombinant human erythropoietin (rHuEPO), introduced into the clinical management of patients with kidney disease during the past decade, provide some experience concerning the forces affecting the use of expensive drugs in a cost-conscious health care system. The decision to prescribe a drug will depend on provider's judgements of the drug's clinical benefits and costs compared with those of other possible therapies. It may also depend on payment policy. Both cyclosporine and rHuEPO were adopted rapidly and extensively by providers of end-stage renal disease care following US Food and Drug Administration approval, despite their high costs. Both drugs were remarkably effective, relatively safe, and able to be administered without great difficulty compared with the therapies they have replaced. There was no additional payment to hospitals for the initial use of cyclosporine, which was introduced in 1983 at the time when Medicare's prospective payment was established, since choice of immunosuppressive agent did not affect the fixed, per-admission payment determined by the diagnosis-related group for kidney transplantation. Medicare coverage for continuing outpatient use of cyclosporine was not initially provided, in contrast to rHuEPO, which was introduced in 1989 with Medicare outpatient coverage and payment of 80% of the allowed charge. Despite their high costs and different methods of insurance payment both drugs achieved a rather quick and high penetration rate into their respective populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the frequency spectrum of the equine electroencephalogram during halothane anaesthesia

The electroencephalogram (EEG) has been used in human clinical anaesthesia as an indicator of cortical activity and as an indicator of the depth of anaesthesia. It would be useful if it provided a reliable indication of the depth of anaesthesia of horses. In this study anaesthesia was induced with thiopentone and maintained with halothane in nine ponies. The end tidal halothane concentration (PE-Hal) was monitored and 20 seconds of EEG were recorded at 0.8 per cent, 1.0 per cent and 1.2 per cent halothane, equivalent to the minimum alveolar concentration (MAC), 1.25 MAC and 1.5 MAC. Each 20 second block of data was divided into one second segments and averaged to give one second of averaged EEG from which a frequency spectrum was obtained by using a fast Fourier transformation. The power of the waveform at low frequency (1 to 3 Hz) was compared with that at higher frequency (9 to 11 Hz). The median frequency and 95th percentile (spectral edge) were also calculated. The spectral edge frequency had the best correlation with PE-Hal.

Postoperative analgesia using phenylbutazone, flunixin or carprofen in horses

Horses undergoing surgery were randomly assigned to one of three groups to receive phenylbutazone at 4 mg/kg (n = 72), flunixin at 1 mg/kg (n = 68) or carprofen at 0.7 mg/kg (n = 63) by slow intravenous injection at the end of surgery, just before they were disconnected from halothane. Pain was assessed by either of two resident surgical clinicians (who did not know which non-steroidal anti-inflammatory drug had been given) when the horses first stood up, two and four hours later and the next morning. If repeated doses of analgesic drugs were given the time was recorded and taken as an end point for the study. The presence or absence of side effects was also recorded. In the three groups there was no significant difference between the types of surgery performed, the numbers of horses requiring further analgesia or the pain scores at any time. In the horses needing further analgesia there was a significant difference in the time after surgery at which the further analgesia was given between those in the flunixin group, 12.8 +/- 4.3 hours (mean +/- sd) and those in the phenylbutazone group, 8.4 +/- 4.6 hours; the carprofen group had an intermediate interval of 11.7 +/- 6.9 hours. Significantly fewer of the horses that received butorphanol during surgery needed further analgesia than of those that did not receive any opioid.

Job analysis 1992: infection control practitioner

The Certification Board of Infection Control directed its Research Subcommittee to compose a Job Analysis Committee in 1991. This 9-member Job Analysis Committee, in collaboration with Applied Measurement Professionals, Inc., conducted a job analysis of ICPs during 1992. The reassessment of the previous Certification Board of Infection Control task analysis, formation of a job-analysis survey tool, and the actual job-analysis process and its results are described in this article. The previous and newly revised test specification outlines are compared. The national Certification Examination for Infection Control for November 1993 will reflect the efforts of this endeavor.

Action spectrum for the effect of day-extensions on flowering and apex elongation in green, light-grown wheat (Triticum aestivum L.)

Fluence-rate response curves for wavelengths from 640 nm to 730 nm were constructed for the day-extension promotion of flowering in green, light-grown, wheat (Triticum aestivum L., cv. Alexandria), a long-day plant. The resultant action spectrum had action maxima at 660 nm and 716 nm and resembles spectra for the high-irradiance reaction (HIR) seen in etiolated plants. Because, the HIR is thought to be controlled by type I pytochrome (that which is most abundant in etiolated tissue) our results indicate the involvement of type I phytochrome in the photomorphogenesis of a light-grown, green plant.

Fatty acid composition of fats of differing melting points extracted from ram subcutaneous tissue

The observation that the subcutaneous fat of pasture-fed Southdown rams consists of two distinct regions is reported. Fatty acid composition of fat from the outer and inner regions of subcutaneous tissue taken from the rib region of eight Southdown rams fed pasture were determined. Relative to the harder inner regions (mean melting point 43.1 degrees C), the softer outer regions (mean melting point 31.8 degrees C) were shown to contain more 9:0-, 15:0-, 17:0-, 17:1-, 18:1-cis and total 18:1 fatty acids; less 14:0-, 16:0-, 18:0- and 18:1-trans fatty acids; and a greater variety and a greater concentration of branched-chain components. Proportions of medium chain-length fatty acids, other than 9:0, did not differ between the layers. The fatty acid contents of serial samples taken at 1-mm intervals through these tissues were determined. Changes in concentrations of components among samples were gradual through the tissues. There was no clear connective tissue sheet, as has been reported for pigs. The inner region of the tissues contains apparently nonrandom fluctuating changes in fatty acid composition.

A unique approach to peritoneal dialysis in infants

Little recorded experience exists concerning the use of chronic peritoneal dialysis in the infant. We herein report the results of a multidisciplinary approach to two infants who were treated with a unique modification of "short-dwell" peritoneal dialysis. A single-bag technique was devised in the hopes of reducing glucose absorption and protein losses while concomitantly permitting a simplified manual method of cycling peritoneal dialysis. The desired nutritional needs of the infants consisted of a caloric intake of 140 calories/kg/d and a protein intake of 3.0 to 4.0 g/kg/d, a goal that often required administration through a nasogastric tube. The timely initiation of peritoneal dialysis and the strict adherence to the prescribed dietary regimen was associated with continued growth in both patients. Repeated developmental assessments of each child were conducted and revealed normal development in one patient and mild delay, but gradual improvement, in the other.

The monounsaturated acyl- and alkyl- moieties of wax esters and their distribution in commercial orange roughy (Hoplostethus atlanticus) oil

Wax esters were isolated from commercial orange roughy (Hoplostethus atlanticus) oil by column chromatography and fractionated by argentation thin layer chromatography. Following transesterification, the resultant fatty acid methyl esters and fatty alcohols were analyzed by gas chromatography. Both acyl- and alkyl-moieties were mainly of the monoene structure within the 16:1-22:1 range. After derivatization, the positions of the double bonds of even numbered fatty acid and fatty alcohol isomers were located by chromatography-mass spectrometry and compared. Results of these positional analyses indicate that the primary desaturation reactions takes place in the delta 9 position of pre-existing (C14 to C24) acyl chains. It is proposed that acyl components from 18:1 are subjected to chain elongation to form a mixture of 24:1 isomers as the final product. Apart from the 24:1 acyl moiety of the wax esters, in which the double bond was almost exclusively in the delta 15 position, de novo biosynthetic reactions on acids and alcohols appear to yield related acyl- and alkyl-moieties of resynthesized wax esters.

Time use of mothers with preschool children: a pilot study

This pilot study describes and compares the time use for physical child care of two groups of mothers--those with physically handicapped preschoolers (N = 16) and those with normal preschoolers (N = 21). Each mother completed a questionnaire on the time she spent in three categories of physical child care activities. These activities included feeding, personal care, and transportation for physical care. Investigators collected data on both frequency and duration. They reported descriptive data for all categories separately and combined. The results of the study show that the mothers of the physically handicapped preschoolers spent significantly more time engaged in physical child care activities than did the mothers of normal preschoolers. Results also show a high correlation between frequency and duration data for physical child care. The results strongly suggest that the mothers of physically handicapped preschoolers spend significantly more time in physical child care than do the mothers of normal preschoolers. They also suggest that frequency data alone could be collected in further studies in this area without appreciably reducing the accuracy of the results.

The carbon dioxide laser in podiatric medicine

The CO2 laser has several distinct advantages in its application to soft tissue lesions of the foot. A dry field is obtained with good hemostasis and clear vision, with easy access in confined areas. The laser beam sterilizes as it cuts, reducing the incidence of infection. In sealing lymphatic channels, it may theoretically diminish the risk of metastasis in malignant lesions. Healing occurs with minimal postoperative swelling, scarring, or pain, leading to increased patient comfort. Other areas in which the laser can be helpful are porokeratosis, keloids, spider web varicosities, and tattoos.

Combined phenotypic and genotypic analysis of ringed sideroblasts in acquired idiopathic sideroblastic anemia

Bone marrow from an 81-year-old male with acquired idiopathic sideroblastic anemia was found to be mosaic for 45,X/46,XY cell lines. Analysis of ringed sideroblasts for the presence or absence of a quinicrine fluorescent Y body indicated that all sideroblastic cells had lost the Y chromosome. The demonstration that the ringed sideroblasts were cytogenetically abnormal in this patient provides evidence that the cytogenetic changes often found in patients with sideroblastic anemia may not be due to randomly acquired chromosome aberrations accompanying tissue aging unrelated to the disease process.

Reese Osteotomy Guide System

This paper has been developed to provide surgeons with a new technique called the Reese Osteotomy Guide System. This technique allows surgeons to perform and determine osteotomies with more precision, resulting in better bone healing, greater stability, and more predictable results.

Temperature- and seed-batch-related variation in the kinetic behaviour of phytochrome under 'high-irradiance-response' conditions

The characteristics of the 'high-irradiance response' (HIR) of plant photomorphogenesis are thought to be the result of the interaction of both the light and dark reactions of phytochrome. Thus any variation in the rates of the dark reactions may be expected to lead to variation in the characteristics of the HIR. We report here substantial differences in the rates of the dark reactions between different seed batches of a single species (Sinapis alba L.), and also between different organs of seedlings from each of the batches of seed. Calculations of phytochrome dynamics from the measured dark-reaction rates show that the behaviour of Pfr under HIR conditions will vary considerably according to seed batch and seedling organ. Much larger differences in dark-reaction rates, and the resulting phytochrome dynamics, were found between 25° and 10° C. These lead to the prediction that the HIR will be much reduced at the lower temperature, and may be absent in some cases.

The role of student volunteers in door-to-door hypertension screening

This study was part of a continuing effort to develop a community-based approach to health care. Student volunteers in seventh- and ninth-grade health classes were trained to take blood pressure measurements and then conduct door-to-door screening for hypertension. One group of student volunteers within each grade level screened households surrounding the school they attended (low-convenience condition), while another group of volunteers screened households adjacent to their own homes (high-convenience condition). The results from these screening methods were compared with the results obtained from a central-site neighborhood screening center. Chi-square tests on the proportion of households screened indicated that the high convenience door-to-door screening method was significantly more effective than either the low-convenience door-to-door method or the central-site screening method. The latter two methods were not statistically different from each other. Both seventh and ninth graders screened significantly more households in the high-convenience condition than in the low-convenience condition. Ninth graders were superior to seventh graders in the high-convenience, but not in the low-convenience, condition.

An analysis of phytochrome action in the 'high-irradiance response'

Using a model based on spectrophotometric measurements of the phytochrome of Sinapis alba L. seedlings we have used the published rate constants for the component reactions of this system to calculate the behaviour of the far-red absorbing form of phytochrome (Pfr), and other parameters, over a period of continuous irradiation. We have then analysed two of the most intensively studied photomorphogenetic responses, hypocotyl extension and anthocyanin synthesis, of these seedlings in terms of various parameters of the model. The results show that many of the main features of the high-irradiance response are correlated with Pfr level. However, a more detailed analysis leads to the conclusion that Pfr alone cannot account for some critical aspects of the response. In particular, it is necessary to hypothesize an additional 'active' component which is a function of the rate of photoconversion.

Pulmonary toxicity of 2-methylnaphthalene: lack of a relationship between toxicity, dihydrodiol formation and irreversible binding to cellular macromolecules in DBA/2J mice

Intraperitoneal doses of 2-methylnaphthalene (2-MN) have been shown to cause pulmonary toxicity in DBA/2J mice. Pretreatment with the monooxygenase inducers sodium phenobarbital and 3-methylcholanthrene (3-MC) failed to protect the DBA/2J mice from the toxic effect of 2-methylnaphthalene. Pretreatment of DBA/2J mice with the monooxygenase inhibitors, SKF 525-A and piperonyl butoxide also failed to enhance or attentuate the pulmonary lesions. Pulmonary and hepatic microsomes from DBA/2J mice metabolized 2-methylnaphthalene to three dihydrodiols, 2-naphthyl alcohol and other unidentified metabolites. Kidney microsomes produced 2-naphthyl alcohol but no detectable dihydrodiols. In comparison to control animals, hepatic microsomes from animals pretreated with sodium phenobarbital produced more of the least polar dihydrodiol, while amounts of the other two dihydrodiols were unaffected. 3-Methylcholanthrene, piperonyl butoxide and diethylmaleate failed to affect dihydrodiol formation in both pulmonary and hepatic microsomes. After the administration of a lung toxic dose (400 mg/kg, i.p.) of 2-MN, irreversible binding was highest in the liver, followed by the kidney, the lung and lastly skeletal muscle. Of the pretreatments given to the mice, only phenobarbital demonstrated a significant effect, and this elevation was apparent only in the liver. A pulmonary toxic dose of 2-MN (400 mg/kg, i.p.) administered to DBA/2J mice significantly depleted reduced GSH in the liver and lung and to a lesser extent, in the kidney. There appeared no good correlation between the pulmonary toxicity of 2-MN-dihydrodiol and/or alcohol formation or the in vivo irreversible binding to macromolecules. These results are compared with those reported previously in C57BL/6J mice.

The influence of light quality on the phytochrome content of light grown Sinapis alba L. and Phaseolus aureus Roxb

The effect on the phytochrome system of light regimes establishing a range of photoequilibria was studied in two light grown dicotyledonous plants, both of which were treated with the herbicide SAN 9789 to prevent chlorophyll accumulation. In Sinapis alba L. cotyledons the results are comparable with phytochrome behaviour in etiolated mustard seedlings; the level of Pfr becomes independent of wave-length whereas the total phytochrome level is wave-length dependent. Contrasting properties are exhibited in Phaseolus aureus Roxb. leaves in which total phytochrome is unaffected by light quality; consequently the Pfr level is dependent on wavelength. Nevertheless, the amount of phytochrome in mung leaves increased after transfer to darkness suggesting that light still has a profound influence on the phytochrome system, even though light quality during the light period and prior to darkness does not.

Phytochrome action in light-grown plants: the influence of light quality and fluence rate on extension growth in Sinapis alba L

Using light-grown plants of Sinapis alba an analysis has been made of the effect on extension growth of adding far red light to a background photosynthetic source. It has been possible to distinguish between the increase in fluence rate and the reduction of the amount of phytochrome present as Pfr, which are both consequences of the addition of supplementary far red light, and to determine that the response of increased extension growth is due only to the latter. It is shown that the degree of fluence rate dependency varies with photoequilibrium and the significance of this interaction is discussed in terms of the mode of action of phytochrome and of its role in the natural light environment.

Nitrate reductase activity (in vivo and in vitro) of ditelosomic stocks of wheat (Triticum aestivum L.)

The nitrate reductase activities (NRA) of 31 ditelosomic stocks were compared with that of the control plant [Chinese Spring (CS) euploid], using in vivo and in vitro assay procedures that had been optimized with respect to the euploid. Fourteen stock exhibited significant differences in in vivo NRA from that of the euploid; the effect of removal of a chromosome arm was always to increase NRA. Eight of these stocks showed similar effects in vitro, although in three, a casein-sensitive factor had to be eliminated before the difference was expressed. Homoeologous group effects were evident among ditelosomics of groups 2, 4, and 7, while for three chromosomes (2D, 7A, and 7B), removal of either are resulted in a similar increase in NRA in vivo and probable in vitro.

Circular-scan streak tube with solid-state readout

A circular-scan streak tube designed for use in a laser ranging system is described. Electrostatic focusing is used between the photocathode and a microchannel plate, and electrons from the microchannel plate are proximity focused onto an output phosphor screen. Electron beam deflection is achieved by driving two orthogonal sets of deflection plate assemblies in phase quadrature at a frequency of 200 MHz. The light intensity in the output beam trace is measured by using a circular Reticon array of 720 photodiodes, which is fiberoptically coupled to the output phosphor screen of the tube. Sample measurements of frequency-doubled Nd:YAG laser-pulse waveforms are given. Also the output beamwidth has been measured at the 200-MHz deflection frequency. The results suggest a limiting resolution of 33 psec for the circular-scan streak tube used for these tests.

The effect of differential root and shoot temperature on the nitrate reductase activity, assayed in vivo and in vitro in roots ofHordeum vulgare (barley) : Relationship with diurnal changes in endogenous malate and sugar

There was a large increase in nitrate reductase activity (NAR) assayed both in vivo and in vitro in roots of barley plants (cv. Midas_ grown with roots at 10°C and shoots at 20°C, compared with whole plants grown at 20°C. There were diurnal fluctuations in NRA in roots from both treatments, but they were much greater in roots grown at 20°C, where NRA fell to a very low value in the dark period. The diurnal fluctuations in the malate content of the roots were also related to the root growth temperature. Plants with roots grown at the lower temperature had a higher malate content, especially in the dark period where it was 20 times greater than in plants with roots at 20°C. At all times there was a three-fold increase in soluble carbohydrate in cooled roots and diurnal fluctuations were much less pronounced than those of malate. Growth at low temperatures increased the total flux of amino N into the xylem sap and increased the proportion of reduced N in the total N flux. At certain times of day both 10°C- and 20°C-grown roots responded to exogeneous malate by increasing the flux of amino acid into the xylem sap, although this effect was always more pronounced in 20°C-grown roots.

Activation, synthesis and turnover of nitrate reductase controlled by nitrate and ammonium in Chlorella vulgaris

Rates of synthesis and turnover of nitrate reductase in Chlorella vulgaris have been estimated from density-labelling experiments. It is demonstrated that nitrate stimulates the rate of turnover of the enzyme. Upon transfer of Chlorella from ammonium to nitrate medium there is a rapid increase in nitrate reductase activity, only part of which is a consequence of increased de novo synthesis: there must also be considerable activation of existing enzyme. It is shown that, in the absence of nitrate, the enzyme is very stable in vivo. Upon transfer from nitrate to ammonium medium, synthesis of nitrate reductase is reduced below the limits of defection. These effects are separate from the reversible (ferricyanide-reactivatable) inactivation of the enzyme which is also observed.

Malignant transformation of polyostotic fibrous dysplasia

We have described an unusual case of polyostotic fibrous dysplasia in a 25-year-old white woman who had malignant transformation into a mesenchymal tumor with widespread metastases and features of rhabdomyosarcoma. Masculinization also occurred with high plasma testosterone levels. A mechanism for the development of masculinizing features is discussed.

Nitrate Reductase and Soluble Cytochrome c Reductase(s) in Higher Plants

The 4S cytochrome c (Cyt c) reductase activity of several plant species was markedly stimulated by cyanide and ferrocyanide but those of the 8S nitrate reductase component and other particulate components of the maize (Zea mays L.) scutellum by comparison, were increased only slightly. The effect of cyanide and ferrocyanide was not due to elimination of cytochrome oxidase interference but resulted from the stimulation of NADH-dependent reduction of Cyt c. A 4S Cyt c reductase component which could be isolated by ammonium sulfate fractionation and diethyl-aminoethyl-cellulose chromatography was found to be stimulated markedly by cyanide and ferrocyanide. The remaining 4S Cyt c reductase, which was insensitive to cyanide and ferrocyanide, was also fractionated with ammonium sulfate into two components. One of these, like the 8S Cyt c reductase, was sensitive to a protease from the maize roots which is relatively specific for nitrate reductase. This 4S Cyt c reductase species could be a subunit of nitrate reductase.

Effects of light on phytochrome in cauliflower curd

The effect of light on the phytochrome content of cauliflower (Brassica oleracea (L.) var. botrytis) curd was studied using in vivo spectrophotometry. It was found that light caused a rapid increase in phytochrome level whereas transfer to darkness caused a rapid loss, regardless of the amount of phytochrome initially present in the far red absorbing form. The amount of phytochrome detectable during continuous irradiation appears to be related to the photoequilibrium φ, and is thus controlled by phytochrome itself.

Analysis of 4-methyloctanoic acid and other medium chain-length fatty acid constituents of ovine tissue lipids

Medium chain-length (C6-C9) fatty acids in depot, intramuscular, kidney, and liver lipids from pasture-fed sheep and subcutaneous and intramuscular lipids from barley-fed sheep were analyzed with emphasis on the 4-methyloctanoic acid (hircinoic acid) content. Within individual animals, the level of hircinoic acid in the subcutaneous fat was usually higher than that either in the deeper depot fats or in the intramuscular fat. Variation of hircinoic acid levels between animals was greatest in the subcutanous fat and least in the perinrphric fat. There were usually higher levels of both branched and odd carbon chain fatty acids in the lipids of barley-fed sheep than in the corresponding lipids of pasture-fed sheep.

Diversity of sequences in total and polyadenylated nuclear RNA from Drosophila cells

Complementary DNA was synthesized using polyadenylated nuclear RNA of cultured Drosophila cells as template. The kinetics of hybridization of this cDNA with nuclear RNA indicated that the complexity of this RNA population is five to ten times greater than that of cytoplasmic mRNA. The same difference in the fraction of DNA represented was obtained when nuclear and cytoplasmic RNA were hybridized with labeled unique sequence DNA. The fraction of the DNA sequences represented in total number of polyadenylated nuclear RNA is much higher than that represented in cytoplasmic RNA.

Rapid activation by phytochrome of nitrate reductase in the cotyledons of Sinapis alba

Nitrate reductase in the cotyledons of etiolated seedlings of Sinapis alba L. responds rapidly to the addition of nitrate. The response is inhibited by cycloheximide at low concentrations. The enzyme is also under phytochrome control. Five minutes of red light irradiation leads instantaneously to a 45% increase in enzyme activity. Increases in activity, linear with respect to time and with no lag phases are promoted by continuous far-red or blue irradiation. These increases are insensitive to cycloheximide. Thus, light and nitrate act through different mechanisms in controlling nitrate reductase activity and phytochrome does not act via controlling the rate of synthesis of the enzyme.

Point-Spread Functions, Line-Spread Functions, and Edge-Response Functions Associated with MTFs of the Form exp [ - (omega /omega(c))(n)]

Point-spread functions, line-spread functions, and edge-response functions associated with modulation transfer functions (MTFs) of the form exp[-(omega/omega(c))(n)] are tabulated for values of the MTF index (n) in the range from n = 1.0 to n = 2.0, in steps of 0.10. The MTFs are also tabulated in this range. Measurements of any one of these four image transfer functions which agree with the tabulated valves for a given set of MTF parameters (omega(c,)n) allow the other three functions to be estimated by using these tables.