Molecular genetics of cryptopleurine resistance in Saccharomyces cerevisiae: expression of a ribosomal protein gene family

The Saccharomyces cerevisiae CRY1 gene encodes the 40S ribosomal subunit protein rp59 and confers sensitivity to the protein synthesis inhibitor cryptopleurine. A yeast strain containing the cry1-delta 1::URA3 null allele is viable, cryptopleurine sensitive (CryS), and expresses rp59 mRNA, suggesting that there is a second functional CRY gene. The CRY2 gene has been isolated from a yeast genomic library cloned in bacteriophage lambda, using a CRY1 DNA probe. The DNA sequence of the CRY2 gene contains an open reading frame encoding ribosomal protein 59 that differs at five residues from rp59 encoded by the CRY1 gene. The CRY2 gene was mapped to the left arm of chromosome X, centromere-proximal to cdc6 and immediately adjacent to ribosomal protein genes RPS24A and RPL46. Ribosomal protein 59 is an essential protein; upon sporulation of a diploid doubly heterozygous for cry1-delta 2::TRP1 cry2-delta 1::LEU2 null alleles, no spore clones containing both null alleles were recovered. Several results indicate that CRY2 is expressed, but at lower levels than CRY1: (1) Introduction of CRY2 on high copy plasmids into CryR yeast of genotype cry1 CRY2 confers a CryS phenotype. Transformation of these CryR yeast with CRY2 on a low copy CEN plasmid does not confer a CryS phenotype. (2) Haploids containing the cry1-delta 2::TRP1 null allele have a deficit of 40S ribosomal subunits, but cry2-delta 1::LEU2 strains have wild-type amounts of 40S ribosomal subunits. (3) CRY2 mRNA is present at lower levels than CRY1 mRNA. (4) Higher levels of beta-galactosidase are expressed from a CRY1-lacZ gene fusion than from a CRY2-lacZ gene fusion. Mutations that alter or eliminate the last amino acid of rp59 encoded by either CRY1 or CRY2 result in resistance to cryptopleurine. Because CRY2 (and cry2) is expressed at lower levels than CRY1 (and cry1), the CryR phenotype of cry2 mutants is only expressed in strains containing a cry1-delta null allele.

Draconian buyers and Spartan suppliers: the harsh realities of a managed care world

In this article, authors Robert Hurley, Ph.D.,and Jon Thompson, M.S.P., report results of a survey involving interviews with employee benefits managers. The results are notable in that they reveal purchasers in the process of challenging many of the fundamental assumptions regarding buying medical benefits and the services of medical professionals.

High-resolution proton nuclear magnetic resonance spectroscopy in the detection of low molecular weight volatiles

Proton nuclear magnetic resonance spectroscopy (1H MRS) has been used to identify ethanol in vivo and to detect other exogenous low molecular weight volatiles in human serum. 1H MRS was used to detect and quantitate 15 human sera containing various concentrations and combinations of ethanol, isopropanol, acetone, and methanol as previously quantitated by headspace gas chromatography. The 1H MRS method was linear for each alcohol. The lowest detectable alcohol concentration was 15 mg/L (peak height equal to three times the signal-to-noise ratio), and 30 mg/L (+/- 10% relative standard deviation) was the lowest level reproducibly quantitated. Within-run and day-to-day coefficients of variation (CV) ranged from 0.8 to 2.0% and 0.9 to 1.2%, respectively, for methanol; 0.5 to 1.9% and 0.6 to 1.3% for acetone; and 0.5 to 1.6% and 0.3 to 2.2% for isopropanol. In all cases, the lowest CVs for a particular compound were obtained for the highest measured concentration (1500 mg/L), and the highest CVs were observed for the lowest concentration (250 mg/L). The 1H MRS method for detection of these volatiles does not require sample pretreatment and is nondestructive, which allows for further analysis by other methods.

High-resolution proton nuclear magnetic resonance spectroscopy in the detection and quantitation of ethanol in human serum

A precise, accurate, and nondestructive method for the detection and quantitation of serum ethanol in humans using proton (1H) nuclear magnetic resonance spectroscopy (MRS) was developed. The 1H MRS method was linear within the range of 30-1500 mg/L. The lowest detectable ethanol concentration was 15 mg/L, with 30 mg/L being the lowest level reproducibly quantitated. Within-run and day-to-day coefficients of variation (CV) ranged from 0.6 to 2.7% and 0.5 to 3.5%, respectively. The excellent day-to-day CVs indicate a negligible loss of ethanol due to volatilization during analysis. Fifteen human serum samples found to be negative for ethanol by headspace gas chromatography (HSGC) had no ethanol as detected by 1H MRS. Twenty-eight human serum samples with ethanol concentrations (determined by HSGC) ranging from 370 to 4440 mg/L were accurately reproduced by 1H MRS. The 1H MRS method required no pretreatment and was nondestructive, thereby allowing for further analysis by confirmatory methods.

Disseminated Strongyloides stercoralis infection

A case of disseminated S stercoralis is an immunosuppressed patient manifested with diarrhea, a rash, and progressive respiratory insufficiency. The parasites were eradicated with thiabendazole despite continued steroid therapy, and the patient survived the hospitalization. The characteristics of S stercoralis allow it to be harbored within a host for prolonged periods of time, only to disseminate once cell-mediated immunity is suppressed. A diagnosis of strongyloidiasis should be considered in an immunocompromised patient with a petechial rash. Prompt diagnosis and initiation of thiabendazole therapy provides the greatest opportunity for patient survival. Secondary bacterial infections should be aggressively sought. Mortality from disseminated strongyloidiasis approaches 80%.

Identification of a DNA-binding protein of human herpesvirus 6, a putative DNA polymerase stimulatory factor

A 41K early nuclear antigen (p41), expressed in human herpesvirus type 6 (HHV-6)-infected T cells, was cloned by screening a cDNA expression library with the anti-p41 monoclonal antibody (MAb) C5. When expressed in mammalian cells, the cloned p41 protein comigrated with the authentic p41 protein from HHV-6-infected cells and localized to the nucleus. HHV-6 p41 shares 44% sequence identity with the human cytomegalovirus (HCMV) DNA-binding protein, ICP36 (UL44 gene product); p41 binds to ssDNA with the same apparent affinity as ICP36. Since ICP36 has recently been shown to be an HCMV DNA polymerase-associated stimulatory factor, a similar function is suggested for p41.

The reliability of ultrasonographic assessment of neonatal hips

Ultrasound scans were made of the hips of 209 neonates born consecutively over a two-week period. Of the 418 scans, 62 images were selected at random and 25 of these were duplicated to give a total of 87 scans. These static images were then presented to five experienced observers who each made nine different assessments and measurements. Interobserver and intraboserver agreement was calculated and expressed as kappa values. Our results showed poor reliability on both counts.

Cataract and survival in an elderly nondiabetic population

Follow-up ranging between 6 and 8 years of the survival of a cohort of 473 elderly nondiabetic subjects randomly selected from a small English town showed an age- and sex-adjusted association between nuclear cataract at the time of baseline examination and decreased survival (P = .002). Comparing those with and without nuclear cataract, the adjusted relative hazard for death was 1.52 (95% confidence interval, 1.15 to 1.99). This effect remained virtually unchanged when also adjusted for whether the subject reported ever having been a smoker.

Accuracy of Goldmann tonometry in clinical practice

The intra- and inter-observer variability of Goldmann applanation tonometry was studied in 8 hospital tonometrists, 4 of whom received brief revision training in tonometer use. Intraocular pressure (IOP) measurements were obtained from 16 glaucoma patients. Over a series of four readings taken from individual eyes, intraocular pressure did not significantly vary. However, a decline in IOP was observed when a second tonometrist obtained a further series of four readings from a previously measured eye. Mean pressures recorded by tonometrists who had received revision training were greater than those obtained by the untrained observers though this could be accounted for by two highly experienced individuals in the untrained group who tended to record low pressures. Comparisons of average readings obtained by two observers on the same eye showed that approximately one-quarter of measurements differed by 2 or more mmHg and approximately one-fifth by 3 or more mmHg.

Intratracheal pulmonary ventilation and congenital diaphragmatic hernia: a report of two cases

Previous studies from our institution have shown that neonates with congenital diaphragmatic hernia (CDH), whose best postductal PaO2 (BPDPO2) was less than 100 mm Hg while on maximal conventional mechanical ventilation (CMV), had a mortality exceeding 90%. When combined with extracorporeal membrane oxygenation (ECMO), the mortality rose to 100% in those infants who developed hypercarbia following decannulation. Historically, those patients have required increasing ventilator support, leading to iatrogenic lung damage, and eventual death. Intratracheal pulmonary ventilation (ITPV) using the reverse thrust catheter (RTC) developed by Kolobow incorporates a continuous flow of humidified gas through a reverse Venturi catheter positioned at the distal end of the endotracheal tube. In animal studies, ITPV was shown to result in a reduced physiological dead-space (VD), to facilitate expiration, and to enhance CO2 elimination. In our current study, we have applied ITPV in two neonates with CDH who could not be weaned from ECMO because of uncontrollable hypercapnia, and who met above criteria for 100% mortality. In both cases, ITPV restored normal PaCO2 at low peak inspiratory pressure (PIP) with a substantial decrease in VD. We believe ITPV is suited to ventilating newborns with CDH in whom barotrauma is known to be common. Beyond its present use, ITPV may be useful to ventilate children with other forms of respiratory failure, and should be so considered along with other now available methods of mechanical pulmonary ventilation.

The 1990/91 Kentucky hospital smoking policy survey: a follow-up

We surveyed all Kentucky hospitals regarding smoking policies iin 1989, 1990, and 1991. There were statistically significant increases in the numbers of hospitals which developed smoking policies and became smoke free between 1990 and 1991. The sale of tobacco in hospitals declined significantly between 1989 and 1991, as did the number of institutions providing smoking areas within the hospital. Survey respondents indicated that the JCAHO mandate prompted changes in smoking policies. Kentucky hospitals are leading the way in developing smoke-free environments, but externally imposed regulations have played a major role in promoting this progress.

Hyperventilation-induced cerebral ischemia in patients with acute brain lesions: demonstration by xenon-enhanced CT

PURPOSE

To examine the possibility that hyperventilation, commonly used to prevent or treat increased intracranial pressure in patients with acute brain lesions, may induce significant cerebral ischemia.

METHODS

Local cerebral blood flow and vascular reactivity were measured before and after hyperventilation using xenon-enhanced CT in 12 patients with acute brain lesions.

RESULTS

Five patients showed "paradoxical" reactivity (increased cerebral blood flow during hyperventilation) within the lesions. In five patients, hyperventilation induced ischemia in apparently normal regions of brain. In three patients, areas of luxury perfusion became ischemic during hyperventilation, while in three patients, lesions with moderate ischemia became more ischemic. Most patients showed more than one type of reactivity.

CONCLUSIONS

These findings document hyperventilation-induced ischemia in acute brain lesions, and demonstrate that this phenomenon affects both injured and apparently intact areas of the brain. Further studies are required to determine the clinical significance of these pathophysiologic changes.

Comparison of the Keeler Pulsair 2000 non-contact tonometer with Goldmann applanation

The Pulsair 2000 non-contact tonometer (Keeler Ltd, UK) is compared with the Goldmann applanation tonometer. Data from 80 eyes were acquired by four experienced observers. A linear regression analysis showed the relationship between the instruments to be: Pulsair = 0.66 + 0.95 Goldmann. Individual components of variation were analysed by analysis of variance which indicated a significant variation in the slope of the regression equation due to observers (p = 0.02) but not to the order in which topical anaesthesia was administered. Differences between two Pulsair instruments were of marginal significance (p = 0.07). The intercept of the regression equation was unaffected by any of the components of variation. Seventy-nine per cent of averaged intraocular pressure measurements obtained with the Pulsair 2000 fell on or within +/- 3 mmHg of those measured with the Goldmann tonometer. It is concluded that the Pulsair 2000 can provide clinically useful measurements of intraocular pressure.

Advanced imaging of osseous maxillary clefts

A computed tomographic (CT) technique to establish precise two-dimensional (2-D) and three-dimensional (3-D) images of the osseous defects of cleft palates is presented and illustrated by two case studies. Prospective soft tissue algorithms and bone detail imaging was made possible by a retrospective program, a specific software program and vertical reformatting technique leading to 3-D image reconstruction. The two cases illustrate the flexibility of the CT program in accurately providing morphometric and bone density data on the location and size of the osseous defects involved in the cleft. Not every cleft palate patient is a candidate for the procedures outlined; however, the diagnosis of and treatment planning for patients presenting with bilateral or extensive osseous clefting can be more accurate.

The effect of a cold environment on protein and energy metabolism in calves

Eleven Holstein bull calves 35 d of age were assigned to one of three treatment groups: (1) W72, warm environment (20 degrees), 72 g feed/kg body weight (BW)0.75 per d, (2) C72, cold environment (-5 degrees), 72 g feed/kg BW0.75 per d, or (3) C90, cold environment (-5 degrees), 90 g feed/kg BW0.75 per d. Fractional synthesis rates (FSR) of protein in the rumen wall, rumen papillae, omasum, duodenum, kidney, liver, heart, longissimus dorsi, biceps femoris and skin were determined following a continuous infusion of [3H]phenylalanine. Phenylalanine flux was elevated in both groups of cold-adapted calves. FSR of protein in the two muscles and skin were reduced along with N retention in the calves in the C72 group compared with the other two groups. Muscle protein degradation, estimated from urinary N tau-methylhistidine excretion, tended to be elevated in both groups of cold-adapted calves. Reduced protein synthesis and increased protein degradation in the C72 group contributed to reduced muscle protein gain. It appears that when feed intake is limited in cold-adapted animals, muscle and skin have a lower priority for nutrients than other organs and tissues, resulting in reduced protein synthesis. It seems unlikely that thermogenesis due to enhanced protein synthesis contributed to the increased heat production in the cold.

Osteosarcoma in a cow

A mass involving the maxilla of a cow was determined to be an osteosarcoma. Microscopically, the mass was composed of plump pyriform cells aligned along thin trabeculae of osteoid. Osteosarcoma rarely develops in large animal species, but when it does, it is usually found in the skull and must be differentiated from more common diseases, such as actinomycosis and tooth abscesses.

Deoxyribonucleic acid (DNA) ploidy and proliferative characteristics of metastatic squamous cell carcinoma determined by flow cytometric analysis

BACKGROUND

The deoxyribonucleic acid (DNA) index and the proliferative index (the fraction of cells in the S phase) can be independent prognostic indicators of the biologic aggressiveness of certain malignant neoplasms.

OBJECTIVE

To determine whether the DNA index or proliferative index could predict metastases in cutaneous squamous cell carcinoma.

METHODS

Nineteen different metastases from 15 patients with primary cutaneous squamous cell carcinoma (SCC) were reviewed, graded, and had DNA proliferative indexing performed by fluorescent activated cytometry. A control group of 13 patients with primary cutaneous SCC without metastases were studied in a similar manner.

RESULTS

No significant difference between the metastatic and the nonmetastatic SCC groups for either DNA index or proliferative index (non-paired t-test) was observed. No correlative association with histologic grading with DNA index or proliferative index was observed for either group.

CONCLUSION

We conclude that aneuploidy and S-phase fraction by fluorescent activated cytometry are not significant predictors of potential metastases in cutaneous squamous cell carcinoma.

A scoring system for lung function tests in infants

Measurements of thoracic gas volume (TGV), airway resistance (Raw), and airway conductance (Gaw) were calculated in a group of 42 normal infants using a whole-body plethysmograph. Maximum expiratory flow at functional residual capacity was measured in a separate group of 108 normal infants. Using data obtained from these infants the following regression equations were calculated: Gaw (L.s-1.cmH2O) = -0.0475 + 0.00164 x length (cm) square root of TGV (mL1/2) = -3.22 + 0.263 x length (cm) VmaxFRC (mL.s-1) = -173 + 5.2 x length (cm). The standard errors of prediction are a measure of the scatter of individual results from the normal population about the true regression line. They were used to define limits of the normal ranges for these tests of lung function, and to develop a scoring system. This approach is preferable to expressing results as percent predicted, which gives no indication of how likely a measurement is to be within normal limits.

Alterations in substrate utilization in the reperfused myocardium: a direct analysis by 13C NMR

An alternative 13C NMR method which allows direct determination of substrate oxidation in tissue for up to three competing 13C-enriched substrates is presented. Oxidation of competing substrates can be measured by 13C NMR spectroscopy under non-steady-state conditions if the relative areas of the glutamate C3 and C4 resonances can be determined. The accuracy of this measurement is limited during brief exposure to 13C-enriched substrates because of the low enrichment in the C3 carbon. The glutamate C4 resonance from a tissue sample which has oxidized a combination of [1,2-13C]acetate (or a uniformly enriched fatty acid mixture) and [3-13C]lactate appears as a nine-line resonance consisting of four multiplet components: a singlet (C4S), two doublets with differing one-bond coupling constants (C4D34 and C4D45), and a quartet (C4Q). It is shown that the sum of the C4S + C4D34 resonance areas versus the C4D45 + C4Q resonance areas directly reports the relative utilization of [3-13C]lactate versus [1,2-13C]acetate, respectively, regardless of citric acid cycle intermediate pool sizes or carbon flux through anaplerotic reactions. We also show that homonuclear 13C decoupling of the glutamate C2 resonance collapses the C3 resonance multiplet into an apparent triplet (actually, a singlet plus a doublet); the relative area of the singlet component reflects the amount of unlabeled acetyl-CoA entering the cycle. The method has been used to determine the contribution of lactate/acetate/glucose to acetyl-CoA in normoxic and reperfused rat hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Occlusion for amblyopia: a comprehensive survey of outcome

The results of a long term follow up of all patients from a single health district started on occlusion for amblyopia in 1983 are reported. Three hundred and sixty-eight patients started treatment, their average age was four years seven months, the average amount of daily occlusion was 1.5 hours and the average length of follow up was 31 months. 37% of cases achieved a final visual acuity of 6/9 or better and another 33% a visual acuity of 6/12 or 6/18.23% did not achieve 6/18 and treatment of these patients was regarded as failure. Data for the remainder (7%) were incomplete. The success rate of occlusion treatment varied little with the age of starting treatment. The group with combined strabismus and anisometropia responded least well to treatment.

Effects of size and growth time of a murine sarcoma on its metastatic spread

The effects of the size of an implanted tumor and of its time of growth on metastasis were examined in the same tumor grown under two different conditions. Tumors were implanted either in the untreated legs of mice or in legs that had been irradiated one day earlier. The radiation slowed the growth of tumors. When the tumors grew to predetermined diameters, the legs were excised and 20 days later the mice were examined for the presence of lung metastases. Equal changes in the time to excision of the tumors grown under the two conditions led to nearly equal changes in the proportions of animals with metastases. Tumor volume effects were not apparent in this consideration of changes in metastasis rates with time. This work reanalyses the data of that study using the variability in growth rates within a tumor growth condition to investigate the effect of tumor size on metastatic intensity. This intensity increased at least linearly with tumor volume for both irradiated and control animals. The finding of equal effect at equal growth times of the implanted tumors under the two growth conditions was confirmed but is due to: (1) metastatic intensity changing five times as rapidly with tumor size in the irradiated group as compared to the control group and (2) non-exponential retarded growth of the tumors in the control treatment group.

Splenectomy in cattle via transthoracic approach

Sixty-eight cattle under general anesthesia were splenectomized. The transthoracic approach was used to provide better access to the spleen and to facilitate ligature of the major splenic vessels. The procedure was easier and less time-consuming, compared with other surgical approaches, and is considered to be less stressful to the animals. Post-operative recovery was complete in 67 of 68 cattle. After surgery, 1 animal developed respiratory tract disease that was thought to have been unrelated to the surgery.

The incidence and prevalence of amblyopia detected in childhood

We present incidence estimates for amblyopia using data from a study of a cohort of 364 children from a single English county who were referred during 1983 for occlusion therapy. Using a criterion of a visual acuity of 6/12 or worse to define amblyopia, we estimate that 3.0% of the county's children develop the condition. Successful treatment of some of these children means that 1.9% will remain amblyopic as adults.

CBF and CBF/PCO2 reactivity in childhood strangulation

Four children with self-inflicted strangulation injuries had cerebral blood flow determined by stable xenon computed tomography (XeCTCBF) within 24 hours of admission. All had suffered a severe hypoxic-ischemic cerebral injury; 3 initially had fixed pupils, all were apneic with varying bradyarrhythmias, and the initial mean arterial pH was 7.26 (+/- 0.18). The initial blood glucose values were greater than 300 mg/dl (334 and 351 mg/dl) in the 2 patients who died compared to the 2 who survived (104 and 295 mg/dl). The cardiac index was depressed during the first several days of hospitalization in the 2 patients who died (less than 2.0 L/min/m2) compared to the 2 who survived. Total CBF was normal (63 +/- 8 ml/min/100 gm) and local variations in CBF were present. PCO2 reactivity was determined by hyperventilating the 4 patients for 20 min from an end tidal PCO2 of 39 +/- 3 torr to 29 +/- 1 torr and then repeating the XeCTCBF study. Marked regional variability in the CBF/PCO2 response was observed, ranging from 0.5-5.5 ml/min/100 gm/torr PCO2. In the 2 patients who died, the CBF/PCO2 was decreased (1.2 ml/min/100 gm/torr PCO2) compared to the 2 patients who survived (2.1 ml/min/100 gm/torr PCO2). Although CBF was normal in these 4 children, the hyperventilation response was depressed, variable, and even paradoxical which may be important in the evolution of further brain injury and is a critical factor in deciding whether hyperventilation may be of clinical benefit.(ABSTRACT TRUNCATED AT 250 WORDS)

Antagonistic effect of atipamezole on xylazine-induced sedation, bradycardia, and ruminal atony in calves

Three doses of an alpha 2-adrenoreceptor antagonist, atipamezole, were administered to reverse xylazine-induced sedation, bradycardia, and ruminal atony in calves. Once a week for 4 weeks, each of 6 calves was administered IV 1 treatment of: 0.3 mg of xylazine/kg of body weight, followed in 10 minutes by 1 ml of 0.9% NaCl; 0.3 mg of xylazine/kg, followed in 10 minutes by 3 micrograms of atipamezole/kg; 0.3 mg of xylazine/kg, followed in 10 minutes by 10 micrograms of atipamezole/kg; or 0.3 mg of xylazine/kg, followed in 10 minutes by 30 micrograms of atipamezole/kg. The order of the 4 treatments in each calf was selected at random. Xylazine alone caused lateral recumbency for 33.6 +/- 7.1 minutes (mean +/- SEM). Atipamezole administered at dosages of 3, 10, and 30 micrograms/kg shortened xylazine-induced lateral recumbency to 20.5 +/- 3.0, 10.2 +/- 0.2, and 9.3 +/- 0.5 minutes, respectively. Calves given xylazine alone stood at greater than 60 minutes after the onset of recumbency. Atipamezole given at 3, 10, and 30 micrograms/kg shortened the time from onset of lateral recumbency to standing to 40.2 +/- 6.9, 12.8 +/- 1.1, and 10.0 +/- 0.7 minutes, respectively. Drowsiness was found in calves given the lowest dosage of atipamezole (3 micrograms/kg) after the calves stood. Atipamezole given at dosages of 10 and 30 micrograms/kg reversed xylazine-induced ruminal atony in a dose-dependent manner. In addition, 30 micrograms of atipamezole/kg reversed xylazine-induced bradycardia, but the lower dosages of this antagonist did not. Results indicated that 30 micrograms of atipamezole/kg should be a useful antidote for xylazine overdose in cattle.

Perspectives in multiple myeloma: survival, prognostic factors and disease complications in a single centre between 1975 and 1988

One hundred and forty-one patients with multiple myeloma, diagnosed at the City Hospital, Nottingham between January 1975 and October 1986, were followed until death or for at least two years in a retrospective study. Overall median survival was 25 months, with no significant improvement occurring during the study period; increasing age, ESR and serum creatinine concentration at diagnosis were independent predictors of shortened survival. Renal impairment developed in 56 per cent of patients but only 7 per cent died of renal failure. At least one episode of infection occurred in 55 per cent of patients, most commonly in the first month. There was a significant rise in the overall incidence of infection and in the proportion caused by Gram-negative bacteria during the study period. Raised serum urea and low haemoglobin concentrations at diagnosis were independent risk factors for subsequent infection. Infection was associated with 2.75-fold increased risk of death, independent of other risk factors. Prevention of infection is an important aim for improvements in the survival of patients in multiple myeloma.

Doppler ultrasound studies in renal arteries of normal newborn babies

The renal arteries of 89 healthy full-term infants were examined using duplex Doppler ultrasonography to establish a normal range for renal blood flow velocity in the first 3 days of life. In the first 24 h a wide range of renal blood flow velocities was noted with a statistically significant decrease in Pourcelot's index over the next 2 days.

Multiple four-wave mixing process in an optical fiber

We report the results of a theoretical and experimental investigation of multiple four-wave mixing processes in the simultaneous propagation of two pump waves through an optical fiber. The pump waves at frequencies omega(1) and omega(2) are observed to generate sidebands at 2omega(2) - omega(1) and 2omega(1) - omega(2) owing to four-wave mixing in the fiber. The power in the sidebands is studied as a function of pump power and detuning. The experimental observations provide a direct verification of the theoretical formalism.

Glutamine metabolism in skeletal muscles from the broiler chick (Gallus domesticus) and the laboratory rat (Rattus norvegicus)

Oxidative decarboxylation of L-[1-14C]glutamine was studied in isolated chick and rat skeletal muscles incubated in the presence of glucose, insulin and plasma concentrations of amino acids. (1) The rate of oxidative decarboxylation of L-[1-14C]glutamine was high, and exceeded that of L-[1-14C]leucine in all muscles. (2) The rate of oxidative decarboxylation of L-[1-14C]glutamine increased with increasing intracellular concentrations of glutamine. (3) The activities of glutamine aminotransferases K and L were more than 10-fold greater in rat than in chick skeletal muscles. (4) Mitochondrial phosphate-activated glutaminase activity was approx. 10-fold greater in chick than in rat skeletal muscles and increased with increasing glutamine concentrations. (5) An inhibitor of glutaminase, 6-diazo-5-oxo-L-norleucine, inhibited the rate of glutamine decarboxylation in chick, but not in rat, skeletal muscle. These findings suggest that glutamine degradation in skeletal muscle may be substantial and may make an important contribution to the regulation of intramuscular glutamine concentrations. A species difference in the pathways and the subcellular location for the conversion of glutamine into 2-oxoglutarate in rat and chick skeletal muscles is implied by the relative activities of glutamine-degrading enzymes.

Fatal adult respiratory distress syndrome following successful treatment of pulmonary strongyloidiasis

Hyperinfection with Strongyloides stercoralis occurs mostly in immunocompromised patients, including those treated with systemic steroids. A case of Strongyloides-induced adult respiratory distress syndrome was recently reported, and we now report a case in which fatal ARDS appeared to result from the successful therapy of massive parasitic infection.