Effectiveness of steam autoclaving on the contents of sharps containers

The effectiveness of steam autoclaving on bacterial endospores placed within five types of sharps containers was tested. A variety of container physical orientations within the autoclave were evaluated. Spores were present on commercial spore strips or placed onto capped and uncapped dental needles. All strips and needles present in empty or filled containers could be sterilized within 15 minutes when the containers were placed on their sides and their vents left open. The contents of containers processed in an upward position required between 30-60 minutes of autoclaving before being sterilized. The size and shape of the containers influenced ease of sterilization.

Influence of chronic alcohol administration on representative indices of puberty and sexual maturation in male rats and the development of their progeny

The effects of chronic alcohol administration on reproductive endocrinology in the developing male rat were examined. Prepubescent male rats (25 days of age) were maintained on an alcohol liquid diet or were pair-fed a control diet until early adulthood and selected indices of sexual maturation were examined at weekly intervals. To determine whether sexually immature animals were more sensitive to the effects of alcohol than adults, fully mature male animals were exposed to an identical period of alcohol exposure and comparisons were made between the two groups. The results demonstrated that alcohol significantly affected many of the primary indices of puberty and sexual maturation. The normal pubertal increases in serum testosterone levels, the weights of the testes and secondary sex organs and beta-endorphin levels in the hypothalamus were substantially reduced in alcohol-exposed animals compared with controls. In contrast to these results, the effects of alcohol on reproductive endocrinology in the fully mature animal were transitory and of considerably less magnitude. After a 2-week alcohol-free period, male rats exposed to alcohol during development were bred with drug-naive primiparous females. Although the same number of pregnancies resulted from matings between alcohol-exposed males and drug-naive females compared with controls, litter sizes were significantly smaller in alcohol-derived offspring than in controls. In all other respects, such as body weights, sex ratios, mortality rates and gross developmental features (eye opening, incisor eruption and testes descent), alcohol-derived offspring were identical with controls. Upon closer examination, however, significant disturbances were detected in alcohol-derived male offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

The medical management of acute appendicitis in a nonsurgical environment: a retrospective case review

The treatment of acute appendicitis in remote environments without the capability of surgical intervention appears to be effective when using antibiotic protocols active against both aerobic and anaerobic bacteria. A review of nine such cases treated with various antibiotic protocols was conducted and demonstrated good response in all patients. This aggressive medical management frequently resulted in complete resolution of symptoms in patients who later required elective appendectomy or who had recurrences, with similar symptoms requiring acute appendectomies. A strong index of suspicion for appendicitis must be maintained in these cases and one must rely on the medical documentation of the initial episode and proceed with a thorough surgical evaluation.

The effects of inhibition of heme synthesis on the intracellular localization of iron in rat reticulocytes

These studies assessed the fate and localization of incoming iron in 6-8-day rat reticulocytes during inhibition of heme synthesis by succinylacetone. Succinylacetone inhibition of heme synthesis increased iron uptake by increasing the rate of receptor recycling without affecting receptor KD for transferrin, transferrin uptake, or total receptor number. Its net effect was to amplify the number of surface transferrin receptors by recruitment of receptors from an intracellular pool. Despite increased iron influx in inhibited cells, only 2-4% of total incoming iron was diverted into ferritin. The majority of incoming iron (65-80%) in succinylacetone-inhibited cells was recovered in the stroma, where ultrastructural and enzymic analyses revealed it to be accumulated mainly in mitochondria. Intramitochondrial iron (70-75%) was localized mainly in the inner membrane fraction. Removal of succinylacetone restored heme synthesis, utilizing iron accumulated within mitochondria for its support. Thus, inhibition of heme synthesis in rat reticulocytes results in accumulation of incoming iron in a functional mobile intramitochondrial precursor iron pool used directly for heme synthesis. Under normal conditions, there is no significant intracellular or intramitochondrial iron pool in reticulocytes, which are therefore dependent upon continuous delivery of transferrin-bound iron to maintain heme synthesis. Ferritin plays an insignificant role in iron metabolism of reticulocytes.

In vivo evidence for a direct effect of naloxone on testicular steroidogenesis in the male rat

It has been suggested that endogenous opioid peptides (EOP) exert paracrine or autocrine effects in the testes. To assess this hypothesis, we examined whether naloxone, by blocking the effects of EOP, influenced serum testosterone levels, apart from its effects on LHRH/LH, in the intact male rat. We found that naloxone increased serum LH and testosterone levels over essentially the same time course and produced dose-dependent increases in serum testosterone levels even though LH levels were maximally elevated at all doses. These data are not consistent with the view that naloxone exerts its effects on testosterone exclusively by altering LHRH/LH release. Additional, perhaps more definitive, evidence of a direct effect of naloxone on testosterone's biosynthesis was provided by our observations that 1) naloxone generated increases in serum testosterone levels in male rats in which the naloxone-induced surge in LH was blocked by nembutal; and 2) intratesticular injections of naloxone increased serum testosterone levels without increasing LH. Although these data suggest that naloxone influences steroidogenesis independently of its effects on LH, we found that the antagonist failed to increase serum testosterone levels in hypophysectomized animals or when serum LH levels were allowed to reach undetectable levels in nembutal-blocked animals. Consequently, our data are consistent with the hypothesis that naloxone facilitates the effects of LH on testosterone's biosynthesis rather than exerting an independent effect of its own. Whether the effects observed in these studies represent a negative autocrine effect of EOP on Leydig cells or a paracrine effect on Sertoli cells remains to be determined. Nevertheless, our results provide, to our knowledge, the first in vivo evidence that EOP modulate testicular steroidogenesis in the intact animal.

The ontogeny of immunoreactive beta-endorphin and beta-lipotropin in the rat ovary

We have investigated the ontogeny of, and the effect of hypophysectomy on, immunoreactive beta-endorphin in rat ovaries. Total levels rose with ovarian weight from nondetectable levels at 5 days of age to approximately 0.15 pmol/ovary at 80 days; thereafter, the levels remained constant through 201 days of age. Hypophysectomy decreased both ovarian weight and the total content of immunoreactive beta-endorphin, but the concentration per weight was not significantly altered. Most of the immunoreactive beta-endorphin before puberty chromatographed like authentic beta-endorphin, but after puberty most chromatographed like beta-lipotropin. Hypophysectomy did not alter this chromatographic pattern.

Age-related differences in the sensitivity to opiate-induced perturbations in reproductive endocrinology in the developing and adult male rat

The effects of a single morphine pellet (75 mg) implanted in developing male rats at 27 days of age on reproductive endocrine parameters were compared to those found in adult (65-day-old) animals after the same treatment. The pellets were left in place to provide the release of morphine during critical phases of puberty and sexual maturation and to prevent an abrupt withdrawal syndrome upon pellet removal which would confound our results. Developing rats were sacrificed at representative intervals after pellet insertion to assess the development of key indices of reproductive endocrinology; adult rats were sacrificed at the same time intervals to permit an evaluation of age-related differences in the sensitivity to opiate-induced endocrine disturbances. Our results showed that morphine markedly influenced a number of endocrine parameters associated with the maturation of the hypothalamic-pituitary-gonadal axis in developing rats for prolonged periods of time, whereas the effects of the opiate in the adult rat were relatively modest and transient. In the developing rat, serum luteinizing hormone (LH), testosterone, the wet tissue weights of the seminal vesicles and testes and hypothalamic LH-releasing hormone (LHRH) levels were substantially depressed immediately after pellet implantation and these effects persisted for up to 4 weeks when compared to placebo-implanted, age-matched controls. In contrast to these results, adult rats showed only transient effects (less than 1 week) of morphine on certain reproductive endocrine parameters (e.g., serum LH, testosterone and the weights of the seminal vesicles) and no effects on others (e.g., testes weights and hypothalamic LHRH).(ABSTRACT TRUNCATED AT 250 WORDS)

The ontogeny of immunoreactive beta-endorphin and beta-lipotropin in the rat testis

We have investigated the ontogeny of immunoreactive beta-endorphin (i-beta E) in the testes of rats from 5 to 150 days of age. i-beta E was measured by RIA in acid extracts of decapsulated testes and characterized by gel filtration chromatography. Significant age-related differences in both the levels and type of i-beta E were observed. Total levels of i-beta E in the testes were very low and barely detectable from 5-20 days of age, but rose sharply in parallel with testes weights from 20-60 days of age; thereafter, no significant changes in i-beta E were found through 150 days of age. Concentrations of i-beta E, expressed in pmol/g testis, fell precipitously between days 5 and 10 and remained relatively constant from 10-150 days. Most of the i-beta E at 5 and 15 days chromatographed like authentic beta-endorphin. However, with the onset of puberty (30-35 days) and during sexual maturation, much of the total i-beta E chromatographed like its' precursor beta-lipotropin (beta LPH). Hypophysectomy decreased the weight and total i-beta E levels of the testes to the same extent without altering the concentrations of i-beta E or the chromatographic pattern of i-beta E. These results indicate that beta E-like and beta LPH-like peptides are present in the rat testis and that age-related changes in both the levels and type of i-beta E correlate with various structural and functional aspects of testicular development.

Time-resolved solution X-ray scattering of tobacco mosaic virus coat protein: kinetics and structure of intermediates

The kinetics of assembly and disassembly of tobacco mosaic virus coat protein (TMVP) following temperature jumps have been studied by small-angle X-ray scattering and turbidimetry. The structures of the principal aggregates of TMVP oligomers (A protein), intermediate size (helix I) and large size helical rods (helix II), have been characterized by their average radii of gyration of thickness, cross section, and shape obtained from the corresponding regimes of the small-angle scattering pattern. This structural information was obtained within seconds after the temperature-induced initiation of either polymerization or depolymerization and allowed us to detect transient intermediates. This methodology made it possible to observe and characterize the structure of a principal intermediate. Taken together with other kinetic information, these data suggest that polymerization of TMVP under virus self-assembly conditions may proceed via a single-layered helical nucleus that contains about 20 subunits. Previous studies have shown that overshoot polymerization of TMVP can occur and results in metastable long helical viruslike rods which subsequently depolymerize and then form short helical rods, depending on the conditions of the final equilibrium state. The longer rods (helix II) are overshoot polymers which form within seconds and contain 17 1/3 subunits per turn (helix IIB), in contrast to the subunit packing arrangement of 16 1/3 subunits per turn found in the shorter helical rods (helix IA). The latter packing arrangement is the one found in TMV. An overall polymerization scheme is proposed for the formation of these two helical forms of TMVP.

Increased cerebrospinal fluid beta-endorphin immunoreactivity in infants with apnea and in siblings of victims of sudden infant death syndrome

To gain further insight into the possible role of endogenous opioid peptides in the respiratory difficulties associated with the apnea of infancy and other disorders possibly related to apnea, the levels of beta-endorphin immunoreactivity were measured in the cerebrospinal fluid (CSF) of five groups of infants: (1) infants with proved apnea, (2) infants with histories of an apparent life-threatening event (ALTE), (3) siblings of victims of the sudden infant death syndrome (SIDS), (4) infants with suspected but unproved apnea, and (5) infants undergoing investigation for other acute illnesses. Twenty-two infants considered at risk for an ALTE (groups 1 to 3) had significantly higher CSF beta-endorphin equivalents (88 +/- 7 pg/mL) than did the 22 control patients in groups 4 and 5 (31 +/- 3 pg/mL). Plasma beta-endorphin immunoreactivity, which was also measured in some of the infants, did not correlate with levels in CSF and, in fact, was significantly lower in the groups at risk for an ALTE (50 +/- 9 pg/mL; n = 14) than in the control subjects (80 +/- 6 pg/mL; n = 11). These studies indicate that elevated beta-endorphin immunoreactivity in CSF may be a marker in infants who have apnea and who may be considered at risk for an ALTE.

Increased plasma beta-endorphin immunoreactivity in scuba divers after submersion

Increased plasma beta-endorphin immunoreactivity in scuba divers after submersion. Med. Sci. Sports Exerc., Vol. 19, No. 2, pp. 87-90, 1987. After submersion under water in a motionless state of neutral buoyancy, scuba divers frequently report feelings of well-being or euphoria similar to those reported after strenuous exercise. Since strenuous exercise is associated with a stress-related increase in plasma beta-endorphin immunoreactivity (beta-EIR), this study was undertaken to measure plasma beta-EIR after submersion in a state of neutral buoyancy under conditions that do not involve strenuous exercise or other extreme stresses. Plasma beta-EIR was measured by radioimmunoassay in male scuba divers before and immediately after remaining motionless 10 ft under water in a state of neutral buoyancy. A significant (P less than 0.01) increase in plasma beta-EIR was found under these conditions. Venipuncture and scuba breathing out of the water did not alter beta-EIR levels. These results indicate that the milder stress associated with submersion in a state of neutral buoyancy involves an increase in plasma beta-EIR similar to that caused by severe stress.

Evaluation of direct saponification method for determination of cholesterol in meats

A gas chromatographic (GC) method has been developed for determination of cholesterol in meats. The method involves ethanolic KOH saponification of the sample material, homogeneous-phase toluene extraction of the unsaponifiables, derivatization of cholesterol to its trimethylsilylether, and quantitation by GC-flame ionization detection using 5-alpha-cholestane as internal standard. This direct saponification method is compared with the current AOAC official method for determination of cholesterol in 20 different meat products. The direct saponification method eliminates the need for initial lipid extraction, thus offering a 30% savings in labor, and requires fewer solvents than the AOAC method. It produced comparable or slightly higher cholesterol results than the AOAC method in all meat samples examined. Precision, determined by assaying a turkey meat sample 16 times over 4 days, was excellent (CV = 1.74%). Average recovery of cholesterol added to meat samples was 99.8%.

The role of endogenous peptides in the action of opioid analgesics

The observation that the narcotic antagonist naloxone could inhibit analgesia produced by electrical stimulation of the brain indicated the involvement of an endogenous chemical in the relief of pain. Multiple endogenous opioid peptides have been identified that have similar pharmacological properties to known narcotic analgesics. The biosynthesis, release, and degradation of opioid peptides have been studied in order to better understand how the manipulation of endogenous opioid systems can be used to produce or augment analgesia. The results of our studies reveal that various conditions and manipulations, such as electrical brain stimulation, acupuncture, stress, and the administration of opioid analgesics, can cause the release of endogenous opioid peptides and possibly endogenous nonpeptide substances. It has also been discovered that nonopioid peptides, such as cholecystokinin, calcitonin, and angiotensin II, can alter the action of opioid analgesics by antagonizing or potentiating their effects. An understanding of the role of endogenous peptides in endogenous opioid mechanisms is necessary for the development of new ways to treat pain and such other disorders as sleep apnea in children (sudden infant death syndrome), head injury, and opioid addiction that involve the activation or alteration of endogenous opioid systems.

Tobacco mosaic virus protein aggregates in solution: structural comparison of 20S aggregates with those near conditions for disk crystallization

Previous X-ray studies (2.8-A resolution) on the crystals of tobacco mosaic virus protein (TMVP) grown from solutions containing high salt have characterized the structure of the protein aggregate as a bilayered cylindrical disk formed by 34 identical subunits [Bloomer, A.C., Champness, J.N., Bricogne, G., Staden, R., & Klug, A. (1978) Nature (London) 276, 362-368]. Under low-salt conditions, 20S aggregates are in equilibrium with 4S species and involved in the efficient nucleation of TMV assembly in vitro [Butler, P.J.G. (1984) J. Gen. Virol. 65, 253-279]. We have investigated by sedimentation velocity and near-UV circular dichroism (CD) measurements the structure of 20S aggregates in low salt (I = 0.1 potassium phosphate at pH 7.0 and 20 degrees C) and the aggregates in high salt [0.2 M (NH4)2SO4 in I = 0.1 tris(hydroxymethyl)aminomethane hydrochloride at pH 8.0 and 20 degrees C, close to the conditions under which TMVP crystallizes as disk aggregates]. At high salt, we observe structures (presumably stacks of disks) having s20,w values around 40, 45, and 50 S, but not the 20S species present in low-salt buffers. The near-UV CD spectrum of 20S aggregates has been obtained for the first time, using computer techniques, from the spectra of the 4S-20S equilibrium mixture and the 4S species. This spectrum of 20S aggregates differs dramatically from that of the stacks of disks examined at both high and low salt (into which the stacks can be returned by dialysis), indicating that the difference is not a solvent effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Fat-Soluble Vitamins. XXVIII. High Performance Liquid Chromatographic Determination of Vitamin D in Pet Foods and Feeds: Collaborative Study

A high performance liquid chromatographic (HPLC) method for vitamin D in pet foods and feeds at low concentrations (2-8 IU/g = 50-200 ppb) was studied collaboratively. The procedure consists of the following purification steps: saponification, extraction oMhe unsaponifiable fraction, chromatography on alumina, cleanup on reverse phase HPLC, and quantitation with straight phase HPLC. The original method, developed by Knapstein, was simplified by deleting the quantitative TLC step. Six coded samples were distributed to 31 laboratories, along with a known sample containing 15 IU/g to allow practice of the rather complicated procedure. Eighteen collaborators returned their results. Results for the spiked samples show good recovery. The estimates of repeatability and reproducibility are 0.96 and 2.2 IU/g for spiked samples and 1.5 and 3.1 IU/g for commercial samples, respectively, which are considered acceptable for these low concentrations. The method has been adopted official first action.

Association-dependent absorption spectra of oxyhemoglobin A and its subunits

A number of factors which lower the oxygen affinity of hemoglobins are also known to produce shifts of the absorption band maxima of the oxyheme. We have studied the variation of the absorption spectra of oxygenated alpha SH and beta SH subunits of human Hb A as a function of their state of association (i.e. alpha, alpha 2, beta, beta 4, alpha beta, or alpha 2 beta 2), and have attempted to correlate the spectral changes with changes to O2 affinity. These studies were carried out under solution conditions (0.1 M Tris, 0.1 M NaCl, 1 mM Na2EDTA, pH 7.4, 10 degrees C) where detailed thermodynamic data for subunit association and oxygen binding are available (Ackers, G. K. (1980) Biophys. J. 32, 331-346). Concentration-difference spectra reveal that the visible and Soret absorption band maxima of beta O2 are slightly red shifted relative to beta 4O8. A unique feature of this spectral change is that the red shift is accompanied by an increase in the ratio of the peak absorbances of the visible alpha and beta spectral bands. By measuring the spectral change as a function of concentration, an association constant of 6.4 +/- 1.9 X 10(15) M-3 was determined for the 4(beta O2) in equilibrium beta 4O8 equilibrium. In contrast, no spectral differences were found between alpha O2 and alpha 2O4 or between oxy alpha beta dimers and oxyHb. Mixing experiments show that the spectrum of oxyHb differs from the average of either alpha O2 + beta O2 or alpha O2 + beta 4O8, but is closer to the former. A comparison between these spectral data and the reported O2 affinities of these species shows that affinity and oxyheme spectra are not correlated.

Resonance Raman and absorption spectroscopic detection of distal histidine--fluoride interactions in human methemoglobin fluoride and sperm whale metmyoglobin fluoride: measurements of distal histidine ionization constants

The pH dependence of the resonance Raman and absorption spectra of human methemoglobin fluoride (HbIIIF) and sperm whale metmyoglobin fluoride (MbIIIF) has been examined. Both the Raman and absorption spectra of HbIIIF and MbIIIF indicate the existence at alkaline pH of an equilibrium between the hydroxide and fluoride complexes. The absorption maxima of HbIIIF and MbIIIF solutions shift to longer wavelengths as the pH is decreased from neutrality. The Raman data show a corresponding shift of the 461- and 468-cm-1 Fe-F vibrational stretching peaks at pH 7.0 [Asher, S. A., & Schuster, T. M. (1979) Biochemistry 18, 5377] to 399 and 407 cm-1 at acid pH in MbIIIF and HbIIIF, respectively. These shifts are interpreted to result from protonation of the distal histidine and the formation of a hydrogen bond to the fluoride ligand. Measurements of the pH dependence of the absorption and resonance Raman spectra give distal histidine ionization constants (apparent) corresponding to pK = 5.1 (+/- 0.1) for HbIIIF and pK = 5.5 (+/- 0.1) for MbIIIF. An examination of the distal histidine pK values and the frequency of the hydrogen-bonded Fe--F stretching vibration at pH 5.0 of HbIIIF with and without inositol hexaphosphate indicates little difference in the distal histidine--heme distance between the so-called R and T quaternary forms of HbIIIF. These results indicate that the changes in the electronic spectrum of HbIIIF that occur upon switching from the R to the T form do not result from alterations in (1) the iron--fluoride bond distance, (2) the iron out-of-heme plane distance, or (3) the distal histidine--fluoride distance.

Studies on the mechanism of assembly of tobacco mosaic virus

Sedimentation and proton binding studies on the endothermic self-association of tobacco mosaic virus (TMV) protein indicate that the so-called "20S" sedimenting protein is an interaction system involving at least the 34-subunit two-turn yield cylindrical disk aggregate and the 49-subunit three-turn helical rod. The pH dependence of this overall equilibrium suggests that disk formation is proton-linked through the binding of protons to the two-turn helix which is not present as significant concentrations near pH 7. There is a temperature-induced intramolecular conformation change in the protein leading to a difference spectrum which is complete in 5 x 10(-6) s at pH 7 and 20 degrees C and is dominated at 300 nm by tryptophan residues. Kinetics measurements of protein polymerization, from 10(-6) to 10(3) s, reveal three relaxation processes at pH 7.0, 20 degrees C, 0.10 M ionic strength K (H) PO4. The fastest relaxation time is a few milliseconds and represents reactions within the 4S protein distribution. The second fastest relaxation is 50-100 x 10(-3) s and represents elementary polymerization steps involved in the formation of the approximately 20 S protein. Analysis of the slowest relaxation, approximately 5 x 10(4) s, suggests that this very slow formation of approximately 20 S protein may be dominated by some first order process in the overall dissociation of approximately 20S protein. Sedimentation measurements of the rate of TMV reconstitution, under the same conditions, show by direct measurements of 4S and approximately 20S incorporation at various 4S to approximately 20S weight ratios that the relative rate of approximately 20S incorporation decreases almost linearly, from 0 to 50% 4S. There appears to be one or more regions of TMV-RNA, approximately 1-1.5 kilobases long, which incorporates approximately 20S protein exclusively. Solutions of approximately 95-100% approximately 20S protein have been prepared for the first time and used for reconstitution with RNA. Such protein solutions yield full size TMV, but at a slower rate than if 4S protein is added. Thus the elongation reaction in TMV assembly, following nucleation with approximately 20S protein, is not exclusively dependent upon the presence of either 4S or approximately 20S protein aggregates. The initial, maximum, rate of reconstitution increases about threefold when the protein composition is changed from 5% to 30% 4S protein, at constant total protein concentration at pH 7.0, 20 degrees C in 0.10 M ionic strength K (H)PO4. The probable binding frame at the internal assembly nucleation site of TMV-RNA has been determined by measuring the association constants for the binding of various trinucleoside diphosphates to helical TMV protein rods. The -CAG-AAG-AAG-sequence at the nucleation site is capable of providing at least 10-14 kcal/mol of sites of binding free energy for the nucleation event in TMV self-assembly.

Confirmatory factor analysis of the WAIS and the WPPSI

Wechsler's hypothesis that verbal and performance factors are the major dimensions underlying the WAIS and the WPPSI subtests was directly tested by using confirmatory factor analysis. Correlated multiple-group factor analyses were performed on the WAIS subtest intercorrelations based on Wechsler's (1955) standardization sample and Doppelt and Wallace's (1955) elderly sample and for the WPPSI subtest intercorrelations based on Wechsler's (1967) standardization sample, separately for each age group. Verbal and performance factors clearly emerged in all analyses, accounting for approximately 70% of total variance for the WAIS and 60% for the WPPSI. The results provide strong support for Wechsler's hypothesis and also for the use of separate verbal and performance scores.

Kinetics and mechanism of tobacco mosaic virus assembly: direct measurement of relative rates of incorporation of 4S and 20S protein

The mechanism of assembly of tobacco mosaic virus has been investigated under conditions in which the rates of incorporation of the 4S and 20S proteins can each be directly measured by analytical centfrifugation. Under these conditions, pH 6.5, 6.5 degrees C, 0.10 M ionic strength potassium orthophosphate, the protein can be made to exist as a metastable 20S aggregate that is necessary for efficient reconstitution. The overall assembly process consists of an initiation (nucleation) reaction that requires two to three 20S disk aggregates per RNA molecule and is followed by an elongation (growth) reaction. In the elongation phase of assembly the 4S protein is incorporated 50 to 70 times faster than the 20S disk, calculated on the basis of a steady-state kinetic analysis. Therefore, under these conditions, in which the rate of assembly is about 0.06 of that at pH 7, 20 degrees C, 0.10 M ionic strength orthophosphate, the 4S protein preferentially participates in the elongation phase. At this slow reconstitution rate intermediate assembly states (about 70-168 S) can be observed. The kinetics of both protein incorporation and nucleoprotein formation suggest that the elongation process is composed of at least two different, possibly sequential, rate-limiting reactions.

Electrocochleography in children. A retrospective study

A follow-up study of 35 children subjected to electrocochleography (Ecog) was conducted to determine (1) agreement of Ecog results with other audiometric measures obtained subsequently, and (2) accuracy of recommendations for patient management made on the basis of Ecog results. The latter was determined by parental experience, educational placement and achievement, and information from medical and paramedical personnel currently managing the children. These data indicate that Ecog test results are valuable in helping select between possible management alternatives in children who are not testable by behavioral means. However, discussion of two "problem" cases points to possible errors of management that could be made if Ecog results were the only available diagnostic information.