Isolation, sequence determination and expression in Escherichia coli of the isopenicillin N synthetase gene from Cephalosporium acremonium

The enzyme isopenicillin N synthetase (IPS) catalyses the oxidative condensation of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (LLD-ACV) to isopenicillin N, which is a central reaction in the pathway to clinically important penicillins and cephalosporins. Here we report the cloning, characterization and expression in Escherichia coli of the gene encoding the IPS protein in Cephalosporium acremonium. The IPS gene was identified by purifying IPS protein, determining the first 23 amino-terminal amino acids, preparing a set of synthetic oligonucleotides encoding a portion of the determined amino-acid sequence, and probing a cosmid genome library with the mixed oligonucleotides. A cosmid hybridizing with the probe was isolated and the IPS gene was localized and sequenced. The IPS gene encodes a polypeptide of relative molecular mass (Mr) 38,416. When this open reading frame was cloned into an E. coli expression vector and inserted into E. coli, the recombinant E. coli produced a new protein co-migrating with authentic IPS as the major protein of the cell (approximately 20% of cell protein). Crude cell extracts condensed LLD-ACV to a penicillinase-sensitive molecule whose antibacterial activity indicated that it was isopenicillin N.

(1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol as an inhibitor of ceramidase

In this study, we have examined the cellular and biochemical activities of the ceramide analog (1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (D-erythro-MAPP). Addition of 5 microM D-e-MAPP to HL-60 human promyelocytic leukemia cells resulted in a concentration- and time-dependent growth suppression accompanied by an arrest in the G0/G1 phase of the cell cycle; thus mimicking the action of exogenous ceramides. Its enantiomer L-e-MAPP was without effect. Two lines of evidence suggested that D-e-MAPP may not function as a direct analog of ceramide. First, D-e-MAPP possesses a stereochemical configuration opposite to that of D-erythro-ceramide. Second, D-e-MAPP failed to activate ceramide-activated protein phosphatase in vitro. Therefore, we examined if D-e-MAPP functioned indirectly by modulating endogenous ceramide levels. The addition of D-e-MAPP to cells, but not L-e-MAPP, caused a time- and concentration-dependent elevation in endogenous ceramide levels reaching greater than 3-fold over baseline following 24 h of treatment. Both D-e-MAPP and L-e-MAPP underwent similar uptake by HL-60 cells. D-e-MAPP was poorly metabolized, and remained intact in cells, whereas L-e-MAPP underwent a time- and concentration-dependent metabolism; primarily through N-deacylation. In vitro, L-e-MAPP was metabolized by alkaline ceremidase to an extent similar to that seen with C16-ceramide. D-e-MAPP was not metabolized. Instead, D-e-MAPP inhibited alkaline ceramidase activity in vitro with an IC50 of 1-5 microM. D-e-MAPP did not modulate the activity of other ceramide metabolizing enzymes in vitro or in cells, and it was a poor inhibitor of acid ceramidase (IC50>500 microM). Finally, D-e-MAPP inhibited the metabolism of L-e-MAPP in cells. These studies demonstrate that D-e-MAPP functions as an inhibitor of alkaline ceramidase in vitro and in cells resulting in elevation in endogenous levels of ceramide with the consequent biologic effects of growth suppression and cell cycle arrest. These studies point to an important role for ceramidases in the regulation of endogenous levels of ceramide.

Genetic transformation of Streptococcus mutans

Three strains of Streptococcus mutans belonging to serotypes a, c, and f were transformed to streptomycin resistance by deoxyribonucleic acids derived from homologous and heterologous streptomycin-resistant strains of S. mutans and Streptococcus sanguis strain Challis. Homologous transformation of S. mutans was less efficient than heterologous transformation by deoxyribonucleic acids from other strains of S. mutans.

Methods used in the CRC program for the determination of carcass yield and beef quality

This paper describes the methodology used for the collection of carcass yield and meat quality data from straightbred and crossbred cattle in the Cooperative Research Centre for Cattle and Beef Quality core program.

Novel genomic imbalances in embryonal rhabdomyosarcoma revealed by comparative genomic hybridization and fluorescence in situ hybridization: an intergroup rhabdomyosarcoma study

A comparative genomic hybridization (CGH) approach provides identification of genomic gains and losses in a tumor specimen in a single experiment. Only 11 embryonal rhabdomyosarcomas (E-RMS) have previously been subjected to CGH. The underlying genetic events in this histologic subtype are not well defined. In this investigation, 12 E-RMS specimens from 10 patients entered into Intergroup Rhabdomyosarcoma Study (IRS) I-IV and two local patients were analyzed by CGH and fluorescence in situ hybridization (FISH). Gains of chromosomes or chromosomal regions 2 (50%), 7 (42%), 8 (67%), 11 (42%), 12 (58%), 13q21 (33%), and 20 (33%) and losses of 1p35-36.3 (42%), 6 (33%), 9q22 (33%), 14q21-32 (25%), and 17 (25%) were most prominent. Chromosomal regions 1p35-36.3 and 9q22 represent novel regions of loss. Importantly, loss of 9q22 corresponds to the locus of a putative tumor suppressor gene (PTCH), which has been shown to play a role in rhabdomyosarcoma in a mouse model of Gorlin syndrome. Loss of 1p36 corresponds to the locus for PAX7, a paired box containing gene characteristically altered in alveolar rhabdomyosarcoma. Moreover, loss of 1p36 is prominent in another common pediatric soft tissue tumor, neuroblastoma. Gains of 2, 7, 8, 12, and 13 and loss of 14 were seen in the sole prior E-RMS CGH series; thus, these data provide important confirmatory results. In contrast to this previous study, however loss, not gain, of chromosome 17 was observed in the current study. Chromosome 17 loss correlates well with previous descriptions of frequent allelic loss of 17p (TP53) in E-RMS. In summary, CGH and FISH analyses of 12 E-RMS specimens revealed novel genomic imbalances that may be useful in directing further molecular studies for the determination of E-RMS critically involved genes.

In vivo and in vitro models of demyelinating diseases. III. JHM virus infection of rats

Suckling rats of three inbred and three outbred strains were inoculated intraperitoneally (P) or intracerebrally (IC) with the JHM strain of mouse hepatitis virus (JHMV) and were monitored for evidence of neurologic diseases. Consequences of varying age at inoculation, route of injection, and virus dose were ascertained. No disease was evident after IP injection but IC inoculation with at least 10(4) plaque-forming units at 2 days of age resulted in either a rapidly fatal encephalitis or a chronic, progressive, fatal neurologic disease in most rats, regardless of strain. Inoculation at 5 or 10 days of age predominantly caused the chronic neurologic disease, characterized by demyelinating lesions in the brain, spinal cord, or optic nerve, which sometimes were evident as late as several months postinoculation. Demyelination in the optic nerve proved to be concurrent with demyelinating lesions elsewhere in the CNS. Occasionally, clinical remissions were observed in rats in which posterior paralysis developed, suggesting that remyelination in the rat can occur. Demonstration of virus replication, by infectivity, in rats exhibiting neurologic disease and in rats without clinical symptoms was substantiated by electron microscopic observations of virus development and assembly in oligodendroglia of the optic nerve and spinal cord. In view of the protracted course of the disease in some rats, presence of demyelinating lesions confirmed by light and electron microscopy, and remissions of clinical symptoms, the JHMV-infected rat seems to be an appropriate animal model to study virus-mediated progressive demyelinating disease.

Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium

The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable acto-myosin interaction, resulting in increased calcium sensitivity. Accordingly, we have developed an apparatus so as to obtain accurate measurements of myocardial interfilament spacing (by synchrotron X-ray diffraction) as a function of sarcomere length (by video microscopy) over the working range of the heart, using skinned as well as intact rat trabeculas as model systems. In both these systems, lattice spacing decreased significantly as sarcomere length was increased. Furthermore, lattice spacing in the intact muscle was significantly smaller than that in the skinned muscle at all sarcomere lengths studied. These observations are consistent with the hypothesis that lattice spacing underlies length-dependent activation in the myocardium.

Factors affecting beef palatability — farmgate to chilled carcass

The potential eating quality of beef is set by the intrinsic structural and compositional characteristics of muscle. However, the extrinsic factors that prevail during the production of the animal, slaughter and processing of its carcass and finally, cooking can produce changes in these structural and compositional characteristics that ultimately manifest as large variations in beef palatability. The conditions that apply in the 24–48 h immediately before and after slaughter are recognised as having the largest influence on beef palatability. This review specifically examines the critical pre- and post-slaughter factors and discusses their putative effects on biochemical and physical changes in muscle and the consequences to beef palatability. Areas for future research within this domain are also discussed.

Intolerance to protein hydrolysate infant formulas: an underrecognized cause of gastrointestinal symptoms in infants

The purpose of this study was to determine the effectiveness of an amino acid-based infant formula in infants with continued symptoms suggestive of formula protein intolerance while they were receiving casein hydrolysate formula (CHF). Twenty-eight infants, 22 to 173 days of age, were enrolled; each had received CHF for an average of 40 days (10 to 173 days) and continued to have bloody stools, vomiting, diarrhea, irritability, or failure to gain weight, or a combination of these symptoms. Sigmoidoscopy with rectal biopsy was performed in all infants. The infants then received an amino acid-based infant formula, Neocate, for 2 weeks. After 2 weeks of treatment, 25 of the infants demonstrated resolution of their symptoms and underwent challenge with CHF. Of the 25 who were challenged, eight tolerated the CHF and the remainder had recurrence of their symptoms. The histologic features in these infants varied from eosinophilic infiltration to normal. We conclude that not all infants with apparent formula protein-induced colitis respond to CHF and that these infants may have resolution of their symptoms when fed an amino acid-based infant formula.

Congenital factor X deficiency: spectrum of bleeding symptoms in 32 Iranian patients

The spectrum of the clinical manifestations of congenital factor X deficiency was studied in 32 Iranian patients. The most frequent symptom was epistaxis, which occurred in 72% of patients, with all degrees of deficiency. Other mucosal haemorrhages (e.g. haematuria, gastrointestinal bleeding) were less frequent and occurred mainly in patients with unmeasurable factor X. Menorrhagia occurred in half of the women of reproductive age. Soft tissue bleeding occurred in two-thirds of the patients; spontaneous haematomas and haemarthroses led to severe arthropathy in five patients. Bleeding from the umbilical stump was an unexpected finding in nine patients. This study demonstrated that the bleeding tendency of factor X deficiency is severe and correlates with factor levels.

High rate of complications associated with peripherally inserted central venous catheters in patients with solid tumours

BACKGROUND

Peripherally inserted central catheters (PICC) have been used extensively as a cost-effective and safe form of medium-term intravascular access. There are only limited data about complications of PICC lines in oncology patients despite theoretical concerns about the higher risks of complications in these patients as a result of cancer itself and cancer therapy.

AIMS

To document the frequency and type of PICC complications in patients with solid tumours.

METHODS

All patients with solid tumours who were treated at Flinders Medical Centre, Adelaide, South Australia, Australia between January 2000 and March 2001 were included in a retrospective review of PICC complications.

RESULTS

Twenty-seven PICC lines were inserted in 17 patients; 40.7% (11/27) of PICC lines developed complications requiring early removal of the PICC. Complications encountered were sepsis (systemic and cellulitis), thrombosis, blockage and leakage. Septic complications were found at a rate of 8/1000 PICC days or 25.7% (7/27) of PICC inserted. The median dwell time was 20 days. The mean time for a complication to occur was 27.5 days.

CONCLUSIONS

The present study demonstrates a high rate of complications, which is higher than the complication rates reported in studies of non-oncology patients. PICC lines should be used with caution in patients with solid tumours. Prospective studies of the factors influencing the incidence of complications might be warranted.

Genetic transformation of putative cariogenic properties in Streptococcus mutans

Rough colonial morphology and bacteriocin production, two properties which may be associated with the cariogenicity of Streptococcus mutans, were transformed into several strain GS-5 mutants defective in each respective property. Transformation was determined by observing the frequency of cotransfer of these properties with different reference markers. The rough colonial transformants were identical to the parental GS-5 strain with respect to ability to synthesize water-insoluble glucans and undergo in vitro sucrose-dependent colonization of glass surfaces. Alterations in the growth medium and the concentration of the initial cell inoculum resulted in an approximate 10-fold increase in the frequency of transformation of strain GS-5 compared to previous observations.

Genetic and phenotypic characterisation of animal, carcass, and meat quality traits from temperate and tropically adapted beef breeds. 4. Correlations among animal, carcass, and meat quality traits

Beef cattle data from temperate (TEMP, n = 3947) and tropically (TROP, n = 4137) adapted breeds were analysed to compute estimates of genetic and phenotypic correlations between animal, abattoir carcass, and meat quality measures. Live animal traits included: liveweight (S2LWT), scanned subcutaneous rump fat depth (S2P8), scanned eye muscle area (S2EMA), flight time (S1FT), and finishing average daily gain (FADG). Carcass traits included: hot carcass weight (CWT), retail beef yield percentage (RBY), intramuscular fat percentage (IMF), subcutaneous rump fat depth (P8), eye muscle length by width (ELW), and meat colour score (MEATC). Meat quality measures taken on 2 muscles [M. longissimus thoracis et lumborum (LTL) and M. semitendinosus (ST)] included: shear force of LTL (LTL_SF) and ST (ST_SF); compression of the ST (ST_C); cooking loss % of the LTL (LTL_CL%) and ST (ST_CL%); Minolta LTL L* (LTL_L*), a* (LTL_a*), ST a* (ST_a*); and consumer-assessed LTL tenderness score (LTL_TEND). Genetic and phenotypic correlations between animal measures and related carcass traits were moderate to very high for TEMP and TROP. Genetic correlations between S2LWT and CWT were 0.89 and 0.82, between S2P8 and P8 0.80 and 0.88, and between S2EMA and ELW 0.62 and 0.68, for TEMP and TROP, respectively. Genetic correlations between animal measures and other carcass traits varied; moderate genetic correlations were estimated between S2P8 and RBY (–0.57, –0.19 for TEMP, TROP) and S2P8 and IMF (0.39, 0.23 for TEMP, TROP). Genetic correlations between animal and meat quality measures were moderate to low. For TEMP, moderate genetic correlations were estimated between S2P8 and LTL_TEND (0.38), FADG and ST_a* (–0.49), and FADG and LTL_TEND (0.45); and for TROP, S1FT and LTL_SF (–0.54), and S2EMA and LTL_L* (–0.46). Phenotypic correlations between animal and meat quality were generally low and close to zero. Several moderate to high genetic correlations existed between carcass and meat quality traits. In general, fatness measures were genetically correlated with tenderness (e.g. IMF and LTL_TEND 0.61, 0.31 for TEMP, TROP). CWT was genetically correlated with meat colour (CWT and LTL_L* 0.66, 0.60 for TEMP, TROP) and objective tenderness measures (CWT and ST_C –0.52, –0.22 for TEMP, TROP). Once again phenotypic correlations between carcass and meat quality were low, indicating that few phenotypic predictors of meat quality traits were identified. Several of the genetic correlations show that both animal and abattoir carcass traits may be of use as indirect measures for carcass and meat quality traits in multiple trait genetic evaluation systems.

ADP-ribosylation factor functions synergistically with a 50-kDa cytosolic factor in cell-free activation of human neutrophil phospholipase D

Proteins in both the cytosol and plasma membrane are needed to reconstitute cell-free phospholipase D activity from phagocytes (Olson, S., Bowman, E. P., and Lambeth, J. D. (1991) J. Biol. Chem. 266, 17236-17242); membrane factors include a small GTP-binding protein in the Rho family (Bowman, E., Uhlinger, D. J., and Lambeth, J. D. (1993) J. Biol. Chem. 268, 21509-21512). ADP-ribosylation factor (ARF) was recently implicated as the cytosolic factor, as it activates phospholipase D in HL-60 membranes. Herein, we show that ion exchange chromatography separates ARF from the major phospholipase D-stimulating cytosolic factor. Both bovine brain ARF and recombinant human ARF-1 stimulated a small amount of phospholipase D activity in the absence of cytosol (about 10% of the response seen with cytosol). With a high concentration of ARF-depleted cytosol, ARF did not further activate. However, at low cytosol, ARF caused marked activation. Thus, ARF synergizes with the cytosolic factor in phospholipase D activation.

Rituximab and immune tolerance in severe hemophilia A: a consecutive national cohort

SUMMARY BACKGROUND AND OBJECTIVES: he management of patients with severe hemophilia A and inhibitors to factor VIII (FVIII) resistant to standard immune tolerance is challenging. There have been recent case reports of the successful use of rituximab in up to 57% of patients as part of rescue immune tolerance regimens. Because case reports and small series are prone to the potential bias of reporting good outcomes and relatively short follow up, a consecutive cohort of all patients treated in the UK with prolonged follow up was analyzed.

METHODS

A national survey of all Comprehensive Care Haemophilia Center in the UK.

RESULTS

A total of 15 patients were reported of whom six (40%) achieved a negative inhibitor titer by Bethesda assay. Durable responses were unusual, observed in only 14% of cases. Clinically significant responses with either a negative inhibitor or an inhibitor titer < 5 BU mL(-1) and no spontaneous bleeding with FVIII replacement were observed in seven (47%) cases. Concomitant use of FVIII appeared to be important. Of the 12 patients treated with rituximab and FVIII, six (50%) achieved a negative inhibitor titer and seven (58%) had a clinically beneficial response. None of the three patients treated without FVIII responded.

CONCLUSIONS

These data suggest that the use of rituximab combined with FVIII is a potentially useful treatment for patients with inhibitors resistant to standard immune tolerance, although sustained inhibitor eradication is uncommon.

Relationship between objective measurements and taste panel assessment of beef quality

The relationship between objective measurements (shear force, compression, drip loss, cooking loss) and sensory evaluation of tenderness and juiciness of samples of M. longissimus thoracis et lumborum was examined using data from 2 experiments which imposed different electrical stimulation and aging treatments post mortem, with resultant differences in sensory and objective measures of tenderness. The relationships were tested first in separate models for each objective measurement, and then in multiple regressions containing all measurements. These models were then repeated with the inclusion of stimulation and aging treatments and their interactions with each objective measurement. Shear force by itself was a useful predictor of sensory tenderness score, with which it had a quadratic relationship. Compression and cooking loss, when used by themselves, accounted for substantially less variation in sensory tenderness scores than did shear force, with larger residual standard deviations (r.s.d.). Drip loss had no significant relationship with sensory tenderness scores. Inclusion of post-slaughter treatment in the analyses increased the amount of variation in sensory tenderness scores accounted for by only a small amount in the case of shear force, with a substantial increase in the case of compression and cooking loss. Use of all objective measurements in the 1 model had a similar predictive ability (r2 , r.s.d.) as the use of shear force plus treatment variables. Aging affected the sensory tenderness scores given by taste panellists, in that they gave 14-day aged meat higher tenderness scores (more tender) than they gave 1-day aged meat with the same shear force, compression or cooking loss values. Electrical stimulation did not affect the relationship between sensory tenderness scores and shear force, but did affect that between sensory scores and compression. The effect was similar to that seen for aged meat, with stimulated meat being scored as more tender by a taste panel than non-stimulated meat, at the same compression values. Post-slaughter treatment did not affect the slope of these relationships. When all objective measurements were analysed together, aging period affected the relationship between tenderness scores and objective measures, with tenderness scores being lower in 1-day aged samples than 14-day aged samples at the same combination of objective measures. There was only a poor relationship between shear force, compression, drip loss, cooking loss and sensory juiciness scores.

Inventory systems of perishable commodities

This paper deals with the blood-bank model; namely, an inventory system in which both arrival of items and demand are stochastic and items stored have finite lifetimes. We assume that the arrival and demand processes are independent Poisson processes. We use an analogy with queueing models with impatient customers to obtain some of the important characteristics of the system.

Dentists' attitudes and behaviors regarding domestic violence. The need for an effective response

BACKGROUND

The authors examined the attitudes and behaviors of a national sample of dentists regarding domestic violence and the barriers dentists face in intervening to help victims.

METHODS

The authors surveyed a national random sample of 321 dentists by mail from November 1997 to March 1998 about their attitudes and clinical practice behaviors related to domestic violence. Survey items were developed based on the domestic violence and health care literature. The authors used the Total Design Method to maximize the response rate and analyzed data to determine differences between dentists who had received domestic violence education and those who had not.

RESULTS

Eighty-seven percent of responding dentists never screened for domestic violence; 18 percent never screened even when patients had visible signs of trauma on their heads or necks. Overall, respondents intervened only minimally to help patients whom they had identified as victims. Respondents reported that the major barriers to screening were the presence of a partner or children (77 percent), lack of training (68 percent), concern about offending patients (66 percent) and their own embarrassment about bringing up the topic of abuse (51 percent). Respondents who had received domestic violence education were significantly more likely to screen for domestic violence and to intervene.

CONCLUSIONS

Dentists face many barriers to identifying and helping patients who are abuse victims, yet these data suggest that education about domestic violence could help them overcome some of these barriers.

CLINICAL IMPLICATIONS

We suggest that dentists follow the AVDR model when approaching abused patients in their practice: Ask about abuse, provide Validating messages, Document presenting signs and Refer victims to domestic violence specialists.

The effect of sire breed on the melting point and fatty acid composition of subcutaneous fat in steers

Fatty acid composition and the melting point of subcutaneous fat was determined in 18 Hereford, 25 Brahman x Hereford, 22 Simmental x Hereford, and 15 Friesian x Hereford steers that were grown out on pasture at two sites and slaughtered when the mean weight of the Herefords at each site was ca. 450 kg. Multivariate and univariate analyses tested the relations of fatty acid composition, degree of saturation, and melting point with sire breed, environment, age, and carcass characteristics. Hereford and Brahman steers were fatter than the Simmental and Friesian steers. Fat from Brahman-sired steers had a melting point 2.5 degrees C lower than fat from the Bos taurus-sired steers at the same age and had a higher proportion of unsaturated fatty acids, independent of variation in carcass weight and fatness. Melting point and degree of saturation decreased as age increased. Step-down discriminant analyses identified a set of three acids (14:0, 16:0, and 17:1) that differed among sire breeds, independent of differences in melting point: the acids 14:0 and 16:0 discriminated between Brahman and Bos taurus steers and 17:1 between Hereford and Simmental and Friesian steers. Increase in fatness was associated with an increase in 17:1, but, at the same fatness, no acids discriminated among the Bos taurus-sired steers. The use of Bos indicus cattle or their crossbreeds in situations in which hard-setting fat is likely may mitigate the problem.

Genetic and environmental effects on the muscle structure response post-mortem

This paper reviewed the mechanisms by which glycolytic rate and pre-rigor stretching of muscle impact on meat quality. If muscle is free to shorten during the rigor process extremes in glycolytic rate can impact negatively on meat quality by inducing either cold or rigor shortening. Factors that contribute to variation in glycolytic rate include the glycogen concentration at slaughter and fibre type of the muscle. Glycolysis is highly sensitive to temperature, which is an important factor in heavy grain fed carcasses. An alternative solution to controlling glycolysis is to stretch the muscle pre-rigor so that it cannot shorten, thus providing an insurance against extremes in processing conditions. Results are presented which show a large reduction in variance (both additive and phenotypic) in tenderness caused by pre-rigor stretching. Whilst this did not impact on the heritability of shear force, it did reduce genotype differences. The implications of these results on the magnitude of genotype effects on tenderness is discussed.