Prevalence of, and risk factors for, physical ill-health in people with Prader-Willi syndrome: a population-based study

The medical findings from a population-based study of Prader-Willi syndrome (PWS) are discussed (in which birth incidence of PWS was estimated at 1:22,000 and death rate at over 3% per annum). In this study the prevalence of specific medical disorders that might account for a shortened life expectancy were investigated. Of all people with a possible diagnosis of PWS, only those meeting clinical criteria and/or with a confirmed genetic diagnosis were included in the study. Sixty-six individuals, 40 males and 26 females with a mean age of 19 years (range of 0 to 46 years) agreed to participate in the population-based study group. A prevalence rate of 25% for non-insulin dependent diabetes mellitus (NIDDM) was found in adults. Mean age at onset was 20 years. Those with NIDDM had a higher past maximum body weight and a greater likelihood of positive family history. Nearly 50% across the age groups reported a history of recurrent respiratory infections. High rates of fractures (29%), leg ulceration (22% in adults), sleep disorders (20%), and severe scoliosis (15% in childhood) were also reported. It is postulated that hypotonia is a possible contributory factor to the risk of strabismus, scoliosis, and respiratory infections. Other causes of morbidity, in particular the high rates of NIDDM, may be due to a failure to manage over-eating resulting in severe obesity. Early diagnosis and clear guidance to families about these risks and how they might be prevented is recommended. It is hypothesized that the high pain threshold may result in the presence of some illness not being apparent.

Prader-Willi syndrome, compulsive and ritualistic behaviours: the first population-based survey

BACKGROUND

Obsessive-compulsive disorder has been reported in association with Prader-Willi syndrome.

AIMS

To report the nature and prevalence of compulsive and similar symptoms associated with Prader-Willi syndrome in a population ascertained as completely as possible.

METHOD

Attempted complete ascertainment of people with Prader-Willi syndrome in eight English counties. Administration of standardised rating scales and a structured interview. Comparison with people with learning disability and high body mass indices.

RESULTS

Prader-Willi syndrome was associated with high rates of ritualistic behaviours, such as the need to ask or to tell something, insistence on routines, hoarding and ordering objects and repetitive actions and speech, compared with the control group, and was negatively correlated with IQ and socialisation age. Typical obsessive-compulsive symptoms, such as checking, counting and cleaning compulsions or obsessional thoughts, were not found.

CONCLUSIONS

Ritualistic and compulsive behaviours occur more frequently in association with Prader-Willi syndrome than among people with intellectual disability and significant obesity.

Does mammographic screening and a negative result affect attitudes towards future breast screening?

OBJECTIVES

To investigate the impact of an experience of a benign mammographic result on intention to seek medical help immediately in the case of breast abnormalities, and on intentions and thoughts about future participation in screening.

SETTING

The Dutch Breast Cancer Screening Programme for women aged 50-69.

METHODS

Subjects were women who were invited for an initial breast examination: 223 women filled out a questionnaire about 10 days before and about 6 weeks after their initial breast examination. To be able to control for possible test effects, another group of 293 women filled out a questionnaire only after mammography. Changes in thoughts and intentions were examined.

RESULTS

Most women were very satisfied with the course of their initial breast examination, although pain or discomfort was often mentioned. No clues to suggest false reassurance were found: more than 99% of the women would consider the possibility of breast cancer if they felt a lump in one of their breasts. In such a situation, most women intended to seek medical help within a week. These variables were not influenced by the experience of mammography with a benign result. In general, women were very positive about (repeat) participation, both before and after screening. After screening, the average woman perceived fewer costs in participating, and perceived her own ability to engage in future screening as higher. However, the experience of pain and anxiety during the initial screening did lead to reverse effects. Women who were less satisfied about their treatment by the staff were more likely to change their intentions to reparticipate in a negative way.

CONCLUSIONS

As, in general, women became more positive about regular participation after they had attended breast cancer screening, efforts to improve first round attendance must be continued. At the same time, the screening organisations must continue to prioritise the high level of client friendliness throughout the screening. No evidence for detrimental effects of screening through false reassurance among participants was found.

Psychotic illness in people with Prader Willi syndrome due to chromosome 15 maternal uniparental disomy

In a population-based study of Prader Willi syndrome (PWS), we investigated the relation between genetic subtypes of the syndrome and psychiatric morbidity. Of 25 patients aged 18 years or older, seven (28%) had severe affective disorder with psychotic features, with a mean age of onset of 26 years (SD 5.9). The seven people affected, all aged 28 years or older, included all five with disomies of chromosome 15, one with a deletion in this chromosome, and one with an imprinting centre mutation in the same chromosome. We postulate that in PWS, an abnormal pattern of expression of a sex-specific imprinted gene on chromosome 15 is associated with psychotic illness in early adult life.

Performance, digesta characteristics, nutrient flux, plasma composition, and organ weight in pigs as affected by dietary cation anion difference and nonstarch polysaccharide

Two dietary cation anion difference (CAD) levels (-100 and 200 mEq/kg) and two dietary nonstarch polysaccharide (NSP) levels (10 and 15%) were used in a 2 x 2 factorial arrangement in two randomized blocks (trials) to evaluate performance, digesta pH and buffer capacity, apparent digestibility, plasma composition, and organ weight in pigs. Seven pigs with a mean initial weight of 7.5 kg were used in each treatment. Pigs had free access to feed and water during the 3-wk experimental period. At the end of the experiment, all pigs were killed approximately 2.5 h after addition of fresh feed. Liver, kidneys, and small and large intestine were removed and weighed immediately. Gastric and small intestinal (divided into two equal parts) digesta were collected. Dry matter, pH, buffering capacity, viscosity, acid insoluble ash, mineral content (Na+, K+, and Cl-), nitrogen, and gross energy content (only in the second part of the small intestine) of the digesta were measured. An interaction (P < 0.05) between dietary CAD and dietary NSP was observed for feed intake, growth, apparent digestibility of DM and gross energy in the distal small intestine, and chloride in the stomach and duodeno-jejunal part of the small intestine. Increasing dietary NSP content increased apparent digestibility of DM and chloride in the stomach and increased apparent digestibility of DM, chloride, sodium, and potassium in the first part of the small intestine. Lowering dietary CAD levels significantly increased apparent digestibility of DM in the first part of the small intestine and decreased chloride influx in the stomach and the small intestine. No significant differences were found for pH, buffering capacity, and viscosity of digesta, except the buffering capacity in the second part of the small intestine, which was higher (P < 0.05) in the 200 mEq/kg CAD group than in the -100 CAD mEq/ kg group. Plasma urea decreased in the low dietary CAD groups and plasma ammonia increased in the high NSP groups. Large intestine weight was significantly less for the -100 mEq/kg CAD groups than for the 200 mEq/kg CAD groups. In conclusion, the effect of CAD on feed intake and growth in pigs depends on dietary NSP levels.

Fermentation of liquid coproducts and liquid compound diets: Part 2. Effects on pH, acid-binding capacity, organic acids and ethanol during a 6-day storage period

The effects of a 6-day storage period on changes in pH, acid-binding capacity, level of organic acids and ethanol of three liquid coproducts [liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW)] and two liquid compound diets [liquid grower diet (LGD) and liquid finisher diet (LFD)] were studied. All products, except LWS, showed a significant decrease in pH and acid-binding capacity during storage. At the end of the storage period, all products reached a pH of between 3.5 and 3.9. In general, it can be concluded that the lactic acid content, and to a lesser extent the acetic acid content, increased dramatically during storage. In contrast, the ethanol content increased significantly in the liquid compound diets only. The pattern of changes in pH and organic acids during the 6-day storage period was different between the liquid coproducts and the liquid compound diets. At the start of storage, liquid coproducts are already in the 'middle' of the fermentation process, while liquid compound diets need approximately 24-36 h before fermentation begins. Consequently, in practice a different approach to obtain fermented diets is needed for liquid coproducts and liquid compound diets.

Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during a 6-day storage period

The effects of a 6-day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid compound diets were: liquid grower diet (LGD) and liquid finisher diet (LFD). The loss of corrected dry matter after a 6-day storage, expressed in relation to the initial content, was 1.9, 6.2, 9.6, 4.6 and 4.2% for LWS, PSP, CW, LGD and LFD, respectively. During storage, the total amount of starch decreased 2.7, 24.0, 28.1 and 33.3% for LWS, PSP, LGD and LFD, respectively. The total amount of lactose decreased 23.5% for CW. The gross energy value of the products did not change remarkably during the 6-day storage period; gross energy losses being less than 3% of the initial gross energy content.

Characterization of Trichoderma reesei cellobiohydrolase Cel7A secreted from Pichia pastoris using two different promoters

Heterologous expression of T. reesei cellobiohydrolase Cel7A in a methylotrophic yeast Pichia pastoris was tested both under the P. pastoris alcohol oxidase (AOX1) promoter and the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter in a fermentor. Production of Cel7A with the AOX1 promoter gave a better yield, although part of the enzyme expressed was apparently not correctly folded. Cel7A expressed in P. pastoris is overglycosylated at its N-glycosylation sites as compared to the native T. reesei protein, but less extensive than Cel7A expressed in Saccharomyces cerevisiae. The k(cat) and K(m) values for the purified protein on soluble substrates are similar to the values found for the native Trichoderma Cel7A, whereas the degradation rate on crystalline substrate (BMCC) is somewhat reduced. The measured pH optimum also closely resembles that of purified T. reesei Cel7A. Furthermore, the hyperglycosylation does not affect the thermostability of the enzyme monitored with tryptophane fluorescence and activity measurements. On the other hand, CD measurements indicate that the formation of disulfide bridges is an important step in the correct folding of Cel7A and might explain the difficulties encountered in heterologous expression of T. reesei Cel7A. The constitutive GAP promoter expression system of P. pastoris is nevertheless well suited for activity screening of cellulase activities in microtiter plates. With this type of screening method a faster selection of site-directed and random mutants with, for instance, an altered optimum pH is possible, in contrast to the homologous T. reesei expression system.

Duration of regrowth of ryegrass (Lolium perenne) effects on grazing behavior, intake, rumen fill, and fermentation of lactating dairy cows

The relative importance of duration of sward regrowth and fill and fermentation in the rumen on the control of grazing time and intake rate during the first grazing session of the day was studied. Four lactating dairy cows were allowed to graze ryegrass (Lolium perenne) swards, with five different regrowth periods after mowing (6, 9, 16, 22, and 30 d). The cows were allowed to graze until they stopped voluntarily (cessation of grazing activity for at least 15 min). Before and after grazing the rumen contents were evacuated, weighed, sampled, and returned to the animals. Samples of rumen liquid were taken immediately before rumen evacuation and approximately 30, 60, 120, and 240 min after the grazing session was finished. Grazing time and intake rate did not follow a significant trend with period of regrowth. Bite rate did not change significantly with duration of regrowth with cows exhibiting high rates of biting for all the sward conditions. Rumen pools sizes of dry matter, neutral detergent fiber, and volatile fatty acids (VFA), measured after grazing, increased significantly with days of sward regrowth, even though the changes over days were small. Concentration of VFA followed a significant quadratic trend with a maximum concentration observed at approximately 110 min after cessation of grazing. In this study, rumen fill, VFA (either total or major components), ammonia, pH, and osmotic pressure as individual variables were not correlated with grazing time or dry matter intake.

Prader-Willi syndrome and psychotic symptoms: 1. Case descriptions and genetic studies

Six people with Prader-Willi syndrome (PWS) who developed psychoses are described. Along with other literature reviewed in the present paper, the results imply an association between PWS and psychotic symptoms. Genetic studies were possible in five cases and SNRPN expression was examined in three cases. Maternal uniparental disomy and 15q11q13 deletions were found, demonstrating that psychotic symptoms are not associated with a single type of genetic abnormality.

Problem behaviors associated with deletion Prader-Willi, Smith-Magenis, and cri du chat syndromes

Problem behaviors of individuals who had one of three chromosome deletion disorders (5p- cri-du-chat, 15q- Prader-Willi, or 17p- Smith-Magenis) were investigated. The Aberrant Behavior Checklist was used. Results were contrasted with those of two groups of people with mental retardation who were described in other studies. The checklist rates many, but not all, potentially relevant behaviors. Eating abnormalities, known to be problematic in Prader-Willi syndrome, and sleep abnormalities, believed to be problematic in Smith-Magenis syndrome, were not included in the survey. All three disorders were associated with greater ratings of problem behaviors than the comparison groups on at least one subscale of the checklist. The results lend support to the partial specificity model of behaviors associated with genetically determined syndromes.

The thermal stability and domain interactions of the mannitol permease of Escherichia coli. A differential scanning calorimetry study

The thermal stability and domain interactions in the mannitol transporter from Escherichia coli, enzyme IImtl, have been studied by differential scanning calorimetry. To this end, the wild type enzyme, IICBAmtl, as well as IICBmtl and IICmtl, were reconstituted into a dimyristoylphosphatidylcholine lipid bilayer. The changes in the gel to liquid crystalline transition of the lipid indicated that the protein was inserted into the membrane, disturbing a total of approximately 40 lipid molecules/protein molecule. The thermal unfolding profile of EIImtl exhibited three separate transitions, two of which were overlapping, that could be assigned to structural domains in the protein. Treatment with trypsin, resulting in the degradation of the water-soluble part of the enzyme while leaving the binding and translocation capability of the enzyme intact, resulted in a decrease of the Tm and enthalpy of unfolding of the membrane-embedded C domain. This effect was much more apparent in the presence of the substrate but only partly so in the presence of the substrate analog perseitol. These results are consistent with a recently proposed model (Meijberg, W., Schuurman-Wolters, G. K., and Robillard, G. T. (1998) J. Biol. Chem. 273, 7949-7946), in which the B domain takes part in the conformational changes during the substrate binding process.

The use of cumulative gas and volatile fatty acid production to predict in vitro fermentation kinetics of Italian ryegrass leaf cell walls and contents at various time intervals

Differences between the fermentation characteristics of cell contents (CC) and protease-treated cell walls (CW) of young leaves of Italian ryegrass (Lolium multiflorum Lam.) cultivar Multimo (tetraploid), were studied in vitro. Gas and volatile fatty acid (VFA) production rates were measured at regular intervals, as was the degradability of organic matter (OM) of CW. The measured VFA were used to predict the gas production and fermentable OM using stoichiometric calculations. For CW the volume and kinetics of measured gas production were the same as those predicted from the VFA formed. In contrast, the measured gas production for CC was consistently less than predicted, indicating that the stoichiometric equations were not valid for rapidly fermenting substrates. For both CC and CW, the relative rate of acetic acid production levelled off more slowly than for other VFA, resulting in an increasing gas yield (in ml/g fermentable OM) after 12 (CW)-24 (CC) h incubation. Consequently, the fermentation of OM was not linearly related to gas production kinetics. For CW, the kinetics of decline of degradable OM and fermentable OM were the same, after correction for a constant 'lost fraction' of degradable OM of 205 g/kg OM. This work indicates the value of detailed studies of fermentation processes to evaluate herbage quality. In particular, the role of CC and the difference between degradation and fermentation require further attention.

Medical opinions, beliefs and prescription of orthopaedic footwear: a survey of Dutch orthopaedists and rehabilitation practitioners

OBJECTIVES

To get insight into medical opinions about the use of orthopaedic footwear and the medical and social factors related to the prescription of orthopaedic footwear by orthopaedists and rehabilitation practitioners.

METHODS

In this study 85 orthopaedists and 96 rehabilitation practitioners filled out a questionnaire measuring perceived desirability of prescribing orthopaedic footwear in specific medical conditions, the perceived advantages of orthopaedic footwear, the perceived disadvantages of orthopaedic footwear, the attitude to orthopaedic footwear and satisfaction with the co-operation with the pedorthist. Clinicians were asked to estimate their referral rate of orthopaedic footwear.

RESULTS

Orthopaedists and rehabilitation practitioners agree that the prescription of orthopaedic footwear should be considered in the case of rheumatoid arthritis, amputation of the foot and diabetic foot and not be considered in the case of sprain and back pain. In the case of hallux valgi, dermatological problems and clavus (severe corn) a reticent prescription policy seems to be the optimal choice. In the other medical conditions studied no unequivocal prescription policy could be derived. Respondents who prescribed orthopaedic footwear more than the median (more than 50 prescriptions per year) were more often rehabilitation practitioner, perceived more advantages of prescription footwear, perceived less disadvantages of prescription footwear and were more satisfied about the co-operation with the pedorthist.

CONCLUSION

In some medical conditions orthopaedists and rehabilitation practitioners agree about the optimal use of orthopaedic footwear. In some other medical conditions orthopaedists and rehabilitation practitioners are divided about the use of orthopaedic footwear. Reported rate of prescription was not related to desirability of prescription, but was related to beliefs such as perceived advantages, perceived disadvantages and satisfaction with co-operation with the pedorthist, underlining the importance of cognitive factors in prescription style.

Relation between the oligomerization state and the transport and phosphorylation function of the Escherichia coli mannitol transport protein: interaction between mannitol-specific enzyme II monomers studied by complementation of inactive site-directed mutants

Previous experiments with the mannitol-specific enzyme II of Escherichia coli, EIImtl, have demonstrated that (1) the enzyme is a dimer, (2) the dimer is necessary for maximum activity, and (3) phosphoryl groups could be transferred between EIImtl subunits [van Weeghel et al. (1991) Biochemistry 30, 1768-1773; Weng et al. (1992) J. Biol. Chem. 267, 19529-19535; Weng & Jacobson (1993) Biochemistry 32, 11211-11216; Stolz et al. (1993) J. Biol. Chem. 268, 27094-27099]. The experiments in this article address the mechanistic role of the dimer. They indicate that the A, B, and C domains of EIImtl preferentially interact within the same subunit. Site-directed mutants in each of the three domains of EIImtl were used to study phosphoryl group transfer by the EIImtl dimer in vitro and mannitol transport in vivo. The C domain mutant, EIImtl-G196D, which was unable to bind mannitol, and the separated C domain, IICmtl, which was unable to phosphorylate mannitol, formed a heterodimer which was capable of mannitol phosphorylation in vitro and mannitol transport in vivo. The rates of phosphorylation were approximately 10-fold lower in heterodimers containing two inactive subunits relative to the rates in heterodimers containing one inactive and one wild type subunit; phosphoryl group transfer through one subunit is kinetically preferred to intersubunit transfer. Heterodimers formed in vivo between one wild type EIImtl subunit and the CB domain double mutant, EIImtl-G196D/C384S, transported mannitol as rapidly as wild type EIImtl alone; the presence of the inactive double mutant subunit did not reduce the transport rate. Thus, only one active A, B, and C domain in the dimer is sufficient for transport and phosphorylation activity, and if all three domains are situated on the same subunit, maximum rates are achieved.

Health education to improve repeat participation in the Dutch breast cancer screening programme: evaluation of a leaflet tailored to previous participants

Participation in breast cancer screening programmes often declines in the course of the programme. The purpose of the present study was to examine whether health education could diminish the amount of drop-outs between two screening rounds. The health education was tailored to women who previously underwent mammography. Based on the Elaboration Likelihood Model two versions of the tailored leaflet were made: a simple version and a version with additional peripheral cues. In an experimental study among 2961 women the effects of the tailored leaflets on reparticipation were tested against a standard leaflet. Re-participation rates were high (> 90%) and did not differ between the 3 groups. No significant differences regarding beliefs about re-participating were found between the 3 groups. Results indicate that the tailored information leaflets did not enhance re-participation. Therefore, the required additional efforts and costs do not seem to be justified. The results of the study provide indications that less painful mammograms and friendly staff might improve re-participation.

Maladaptive behaviour in Prader-Willi syndrome in adult life

Thirty adults with Prader-Willi syndrome (PWS) were compared with 30 adults with non-specific learning disability matched for age, sex and severity of mental retardation. Maladaptive behaviour was assessed with the Aberrant Behavior Checklist (ABC), a 58-item structured interview which rates behaviours from 0 (not a problem) to 3 (severe problem) and which yields five factors (I) irritability, agitation; (II) lethargy, withdrawal; (III) stereotypic behavior; (IV) hyperactivity, non-compliance; and (V) inappropriate speech). The PWS sample had significantly higher factor I (P < 0.001) and factor V (P < 0.05) scores. The PWS sample had mean scores above 1 for 17 ABC items; the contrast subjects had no mean scores above 1. The factor I scores for the PWS sample were similar to those of inpatients in hospital facilities for adults with mental retardation and mental illness or severely challenging behaviour. The results support previous work, and extend it by suggesting that temper tantrums, self-injury, impulsiveness, lability of mood, inactivity and repetitive speech are characteristic behaviours in PWS in adult life. Studies of the reasons for heterogeneity in behaviour are now needed.

Phosphorylation site mutants of the mannitol transport protein enzyme IImtl of Escherichia coli: studies on the interaction between the mannitol translocating C-domain and the phosphorylation site on the energy-coupling B-domain

Mannitol binding and translocation catalyzed by the C domain of the Escherichia coli mannitol transport protein enzyme IImtl is influenced by domain B. This interaction was studied by monitoring the effects of mutating the B domain phosphorylation site, C384, on the kinetics of mannitol binding to the C domain. The dissociation constants for mannitol to the C384 mutants in inside-out membrane vesicles varied from 45 nM for the wild-type enzyme to 306 nM for the mutants. The rate constants pertinent to the binding equilibrium were also altered by the mutations. The association rate of mannitol to the cytoplasmic binding site in the mutants was accelerated for all mutants. The exchange rate of bound mannitol on the wild-type enzyme was shown to be pH dependent with a pKa of approximately 8 and increasing rates at higher pH. This rate was increased for all the mutants, but the pKas differed for the various mutants. The exchange rate for binding to the isolated IICmtl, however, was not pH dependent and exhibited a low rate. Exchange measured at 4 degrees C showed that, of the two steps, binding and occlusion, involved in binding to wild-type EIImtl in inside-out vesicles, only one could be detected for the C384E and C384L mutants. This suggests that the mutations increased the rate of the occlusion step so that it was no longer separable from the initial binding step or that the mutations eliminated the occlusion step altogether. The change in the mannitol binding kinetics of the C domain indicates that the B and C domains of EIImtl influence each other's conformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression, purification, and kinetic characterization of the mannitol transport domain of the phosphoenolpyruvate-dependent mannitol phosphotransferase system of Escherichia coli. Kinetic evidence that the E. coli mannitol transport protein is a functional dimer

The overexpression of the membrane-bound C domain of the mannitol transport protein EIIMtl of Escherichia coli has been achieved. This protein, IICMtl, consisting of the first 346 amino acids, was purified from membrane vesicles and still bound mannitol with a high affinity. Gel filtration experiments showed that purified IICMtl was a dimer, confirming that the interaction within the EIIMtl dimer occurs between the membrane-bound portions of the protein. IICMtl in combination with a chimeric protein consisting of the membrane-bound EIIGlc C domain and the cytoplasmic EIIMtl BA domain could restore both phosphoenolpyruvate-dependent phosphorylation and mannitol/mannitol-P exchange activity. The interaction in this complex was comparable to that of IICMtl with soluble IIBAMtl in as much as there appeared to be no specific interaction between IICMtl and the membrane-bound EIIGlc C domain; the Km of IICMtl for the chimer was so low that saturation could not be achieved. In contrast, a very high affinity with a Km of 2 nM was measured between purified IICMtl and purified EIIMtl. This interaction was manifested in a IICMtl-dependent stimulation of the EIIMtl catalyzed phosphoenolpyruvate-dependent mannitol phosphorylation reaction and the mannitol/mannitol-P exchange reaction. The high affinity of IICMtl for the wild type enzyme can be explained by the formation of heterodimers consisting of a IICMtl monomer and an EIIMtl monomer which interact at the level of the membrane-bound domains. The 2-fold increase in mannitol phosphorylation activity of the hetero- versus homodimer is an indication that the individual subunits in the homodimer are functionally coupled and work at only half their maximum rate. It is known that the EIIMtl dimer, but not the monomer, catalyzes the mannitol/mannitol-P exchange reaction. Since the heterodimer also catalyzes this reaction, it appears that only one functional B domain is required per dimer.

Expression and characterization of a structural and functional domain of the mannitol-specific transport protein involved in the coupling of mannitol transport and phosphorylation in the phosphoenolpyruvate-dependent phosphotransferase system of Escherichia coli

The mannitol-specific transport protein in Escherichia coli, EIImtl, consists of three structural and functional domains: a hydrophilic EIII-like domain (the A domain); a hydrophobic transmembrane domain (the C domain); and a second hydrophilic domain (the B domain) which connects the A and C domains together. The A domain contains the first phosphorylation site, His554, while the B domain contains the second phosphorylation site, Cys384. The phosphoryl group which is needed for the active transport of mannitol is sequentially transferred from P-enolpyruvate via the two phosphorylation sites to mannitol bound to the substrate binding site. In this paper, the expression, purification, and initial characterization of the B domain, IIBmtl, are described. Oligonucleotide-directed mutagenesis was used to produce an amber stop codon (TAG) and HindIII restriction site in a flexible loop between the B and A domains in the subcloned gene fragment coding for IIBAmtl (van Weeghel et al., 1991c). The gene fragment coding for IIBmtl was then subcloned behind strong promoters, located in two different expression/mutagenesis vectors, which directed the expression of the 15.3-kDa polypeptide in Escherichia coli. The domain was purified from E. coli crude cell extracts by using Q-Sepharose Fast Flow, S-Sepharose Fast Flow, and hydroxylapatite column steps. This purification procedure resulted in 1 mg of pure IIBmtl/g of cell, wet weight. The purified B domain was analyzed in vitro for its catalytic activity with membranes containing the phosphorylation site mutant form of EIImtl, C384S, and with the transmembrane domain, IICmtl. The B domain, together with purified IIA, was able to restore the P-enolpyruvate-dependent phosphorylation activity of the membrane-bound C domain. Steady-state mannitol phosphorylation kinetics at saturating EI, HPr, and IIAmtl yielded an apparent Km of P-IIBmtl for IICmtl of 200 microM and an apparent Vmax of 71 nmol of mtl-P min-1 mg of membrane protein)-1. This Vmax value is comparable to that of wild-type EIImtl measured under the same experimental conditions.

Absorption of volatile fatty acids from the rumen of lactating dairy cows as influenced by volatile fatty acid concentration, pH and rumen liquid volume

The effect of rumen liquid volume, pH and concentration of volatile fatty acids (VFA) on the rates of absorption of acetic, propionic and butyric acids from the rumen was examined in lactating dairy cows. Experimental solutions introduced into the emptied, washed rumen comprised two different volumes (10 or 30 l), four levels of pH (4.5, 5.4, 6.3, 7.2) and three levels of individual VFA concentrations (20, 50 or 100 mM-acetic, propionic or butyric acid). All solutions contained a total of 170 mM-VFA and an osmotic value of 400 mOsmol/l. Absorption rates were calculated from the disappearance of VFA from the rumen corrected for passage with liquid phase to the omasum. An increase in initial fluid pH caused a reduction in fractional absorption rates of propionic and butyric acids. Increasing the initial pH from 4.5 to 7.2 reduced fractional absorption rates of acetic, propionic and butyric acids from 0.35, 0.67 and 0.85 to 0.21, 0.35 and 0.28/h respectively. The fractional absorption rates of all VFA were reduced (P < 0.05) by an increase in initial rumen volume. The fractional absorption rate of acetic acid was lower (P < 0.05) at an initial concentration of 20 mM than of 50 mM. The fractional absorption rate of propionic acid tended (P < 0.10) to decrease as the level of concentration increased while fractional absorption rate of butyric acid was not affected by butyric acid concentration. These results indicate that relative concentrations of VFA in rumen fluid might not represent relative production rates and that attempts to estimate individual VFA production from substrate digestion must take account of pH and VFA concentration.

In vitro enzymatic hydrolysis of protein and protein pattern change of soya and faba beans during germination

In addition to technological processes like heat treatment, germination can be an alternative process for the improvement of protein quality of legumes. This was demonstrated by enzymatic protein hydrolysis of flour of germinated faba and soya beans, using a pepsin-pancreatin enzyme system. SDS-PAGE was used to study the changes in protein pattern of these legumes during germination. In addition, the effect of germination on the content of condensed tannins in flour from germinated faba beans and trypsin inhibitors in flour from germinated soya beans were studied. Germination for five days resulted in a maximum increase in enzymatic protein hydrolysis by 21.3% in flour from faba beans and by 25.7% in flour from soya beans after 12 hours of germination. Protein patterns, obtained with SDS-PAGE demonstrated a considerable protein breakdown during germination between day 2 and 3 in faba beans and between day 1 and 2 in soya beans. The tannin content in flour from faba beans decreased by 29.7% after seven days of germination, but the tannin content of the hulls of the faba beans did not change during that period of germination. The trypsin inhibitors in flour from soya beans decreased by 25.5% after seven days of germination. We conclude that the increased enzymatic hydrolysis of protein in both legumes cannot be explained by a decrease of tannins or trypsin inhibitors. The possible explanation is that through degradation of proteins during germination of the legumes, the cleaved protein fragments are more susceptible for hydrolysis by pepsin-pancreatin.

The development of reactions of the public to warning and emergency situations in France, Greece, and the Netherlands

This article describes the different reactions to emergency warning messages among residents living within a 3-km radius of a hazardous chemical complex and by people living at least 10 km from an industrial site in France, Greece, and the Netherlands. Belief in warning, primary and secondary appraisal, emotional response, and adherence to normal routine were assessed by conducting face-to-face interviews in which a four-phase scenario simulating a credible industrial accident was presented. The results showed that respondents who did not reside in the neighborhood of the hazardous site were, in general, more inclined to trust the warning messages than respondents who resided in the neighborhood were. With the exception of primary appraisal, the warning phases evoked very distinct reactions in the respondents from all three countries with regard to warning belief, secondary appraisal, emotional response, and adherence to normal routine.

Digestion of alfalfa and grass silages in sheep. 2. Digestion of protein in reticulorumen and intestines

Wilted lucerne and grass silages were given to mature wethers. Estimates of degradability of proteins in the reticulorumen were lower with diaminopimelic acid (38-71%) than those based on amino acid profiles of dietary, microbial and duodenal proteins (64-87%). Microbial protein synthesis was related to extent of organic matter fermentation in the reticulorumen. Efficiency of protein synthesis was not different between silages. Apparent digestibility of protein and amino acids in the small intestine was lower for lucerne silage (54%) than for grass silage (60-63%), probably caused by a higher DM passage in the small intestine of lucerne silage. Relative to the amino acid profiles of milk protein and beef, histidine and methionine were the first limiting amino acids. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Digestion of alfalfa and grass silages in sheep. 1. Rates of fermentation in and passage from the reticulorumen

Wilted lucerne and grass silages were given for 9 weeks (3 weeks adaptation, 6 weeks experimental) to mature wethers. Fractional rate of passage of particles (kp) from the reticulorumen, as determined with chromium-mordanted neutral detergent fibre (Cr-NDF), was negatively related to digestibility, but positively to feed intake. Ratio of kp to kl (liquids) decreased with higher intake of indigestible material. Models were developed to interrelate cell wall pool in the reticulorumen, passage of undegraded cell walls in the proximal duodenum, fractional rate of passage of particles, fractional rate of degradation of cell walls (kd), and the proportion of large particles (fL) within the total particle pool in the reticulorumen. Although estimates of kd and fL were not very accurate yet, differences between silages could be characterized. The kd values of cell walls in grass silages were negatively related and fL positively related to stage of maturity at harvesting. For silages with similar kd, the extent to which cell walls left the reticulorumen was higher with lucerne than with grass silage. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Potential radiopharmaceuticals for the detection of ocular melanoma. Part II. Iodoquinoline derivatives and 67Ga-citrate

The uptake and distribution of several 4-(substituted amino)-iodoquinolines, 131I-labelled, and of 67Ga-citrate were investigated in Syrian golden hamsters with Greene melanomas. Because of its uptake in the melanoma (tumour/eye ratio 8.9), 4-(dimethylamino-ethylamino)-7-iodoquinoline (NM113) was selected for further investigations as a possible radiopharmaceutical for ocular scintigraphy when labelled with 123I. High uptake of NM113 turned out to be incidental and could not be favourably influenced by several pharmacological pretreatments. Affinity for melanin, as shown in in vitro experiments, unfavourably influences NM113 tumour-to-eye ratios. In comparison with 67Ga-citrate, the latter, with a high tumour-to-eye ratio (44.8 after 24 h) is more promising in patient studies in which NM113 123I was not.

Incorporation of [125I]-5-iodo-2-thiouracil in cultured hamster, rabbit, and human melanoma cells

The incorporation of [2-14C]-2-thiouracil and a series of [125I]-5-iodo-2-thiouracils ([125I]ISUra(s)) into cultured Greene hamster melanoma cells was determined in order to establish their properties as false precursors in the melanin-biosynthetic pathway. The cold trichloroacetic acid-precipitable incorporation of [2-14C]-2-thiouracil as well as [125I]ISUra into melanoma cells after a 24- to 48-hr labeling period proved to be completely tyrosinase dependent (more than 99.5% inhibition could be achieved by 0.5 mM phenylthiourea). [125I]ISUra incorporation was 3-fold higher than was [2-14C]-2-thiouracil incorporation and was enhanced by 1 mM theophylline treatment. [125I]ISUra incorporation into hamster, rabbit, and human melanoma cells showed a linear relationship with cell melanin content. Methylation of the sulfur completely prevented the incorporation, while propylation but not methylation at position 6 resulted in lower incorporation. [125I]ISUra proved to be a marker for melanogenesis and may be useful in studies on the differentiation of cultured melanoma cells.

Effect of frequency of feeding and dietary treatment on metabolism, performance and carcass characteristics of swine

In a 3 X 2 factorial design of experiment 96 growing pigs weighing 20 kg initially were given a ration based on maize which is normally used for performance testing in the Netherlands or a least-cost ration with more byproducts, twice daily at 50, once daily at 100 or once every 2 days at 200 g/kg0.75. Metabolism trials were made when the pigs reached 35, 65 and 85 kg. Blood was sampled at intervals just before feeding. Growth rate and feed efficiency were greater in pigs fed once daily than in those fed twice daily by 4 and 3% respectively. Nonesterified fatty acids in blood showed that pigs need be fed only once daily. Performance of pigs fed every 2 days was poor. The least-cost ration caused a decrease in growth rate and feed efficiency but produced thinner backfat and a greater percentage of meat. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The penetration of the embedding medium methyl methacrylate in undecalcified bone

Cutting artifacts in microtome sections prepared from undemineralized methyl methacrylate embedded bone are due to the almost complete absence of methacrylate in the intercellular compartment of the bone tissue, the soft tissues being fully impregnated with the polymer. The osteocyte system is only partially penetrated by methacrylate.