The effect of clinical use and sterilization on selected orthodontic arch wires

The effect of clinical use and various sterilization/disinfection protocols on three types of nickel-titanium, and one type each of beta-titanium and stainless steel arch wire was evaluated. The sterilization/disinfection procedures included disinfection alone or in concert with steam autoclave, dry heat, or cold solution sterilization. No clinically significant differences were found between new and used arch wires. The direction of load application to the arch wire and the particular segment of arch wire tested was found to cause substantial differences in generated loads for certain arch wire types.

Bioactive peptides and serotonin in the gut endocrine cells of the crocodile, Crocodylus niloticus (Laurenti 1768): an immunocytochemical study

Little is known about peptide-storing endocrine cells in the gut of the Nile crocodile. As in the case of other reptiles, particularly the alligator, a limited range of peptide-storing cells was found in the gut of the crocodile. They were somatostatin, glucagon, gastrin, neurotensin and pancreatic polypeptide. The topographical distribution of cells immunoreactive to somatostatin and gastrin in the gut of the crocodile is comparable to the situation in the alligator. Glucagon and neurotensin immunoreactive cells have a much wider distribution in the gastro-intestinal tract of the crocodile compared to the alligator. Cholecystokinin and bombesin cells previously reported in the small intestine of the alligator were not detected in this study. This is the first report to demonstrate pancreatic polypeptide and serotonin immunoreactivity in the gut of a crocodilian specie.

An allometric-autoregressive approach to poultry development

1. The relative rates of development in a commercial layer and a broiler strain of chicken fed 180 or 230 g crude protein/kg were investigated by the use of the allometric-autoregressive model. Development was divided into pre-pubertal (0 to 8 weeks) and pubertal phases (8 to 22 weeks). 2. Significant strain effects were observed, at all ages, in rates of gain of live (L) body mass, carcass (C) mass, non-carcase (N) mass and empty-body (EB) mass as well as C, N and EB moisture, protein and fat content. 3. Significant dietary effects were observed in C and EB fat in the pre-pubertal phase and L mass, N protein and C fat in the subsequent pubertal period.

Influence of phased inclusion of halofuginone on broiler skin tensile strength and growth performance

The effect of continuous administration, weekly 24 h administration, phased withdrawal and phased inclusion of dietary halofuginone at 3 mg kg-1 on skin tensile strength was tested in Ross I broiler pullets. Controls received monensin continuously at 100 mg kg-1. A total of 2,592 birds were used in 2 lots of 1,296 in 2 separate programmes. Continuous dietary administration of halofuginone affected skin tensile strength negatively (P less than 0.05), with an equally significant recovery following a 7 d withdrawal period. A polynomial regression analysis indicates that skin strength may undergo a slight compensatory overstrengthening reaction within 7 d of withdrawal of halofuginone. Weekly 24 h administration of halofuginone reduced differences in skin strength between treatment and controls to non-significant levels. Differences in skin strengths between controls and the halofuginone phased inclusion programme decreased as the birds aged, being significant (P less than 0.05) on Days 14 and 28 and non-significant on Days 21, 35, 42 and 49. A weakening of skin tensile strength of broiler carcasses, as far as it may be influenced by halofuginone, can be alleviated through different shuttle programmes involving halofuginone. Such programmes would include intermittent dosing, a withdrawal period, administration to older birds or a combination of these programmes.

Aesthetic provisional restoration for the partially edentulous, immediate, postimplantation patient

This article reviews the methods currently used for making provisional restorations for endosseous dental implants. With the requirements for osseointegration in mind, a simple and aesthetic alternative is suggested. The clinical and laboratory stages for the fabrication of the prosthesis are outlined.

Influence of continuous dietary halofuginone on broiler skin tensile strength and growth performance

Halofuginone was administered to both sexes of 2 broiler strains, Ross and Hubbard, in 4 dietary treatments, 0, 1.5, 3 and 6mg kg-1. Controls received dietary monensin at 100 mg kg-1. Group feed intake and body mass were recorded weekly. Skin tensile strength was monitored on Days 28, 35, 42 and 49 using a standardised cut of breast skin from carcasses randomly drawn from each treatment, strain and sex combination. Halofuginone inclusion level was inversely correlated (r = -0.36) with skin tensile strength and affected both sexes of the 2 strains (P less than 0.01). Between sexes, the skins of cockerels were consistently stronger than those of hens (P less than 0.01). The effect of age (P less than 0.07) and that of strain (P less than 0.06) tended towards significance at the 5% level. The singular effect of halofuginone on skin tensile strength was masked by the interactions treatment and sex (P less than 0.01); treatment and age (P less than 0.02); treatment and strain (P less than 0.06); age and strain (P less than 0.01). An inclusion level of 6mg kg-1, double the recommended level, could reduce growth and skin tensile strength significantly.

Cloning and characterization of a gene encoding extracellular metalloprotease from Streptomyces lividans

The prt gene, encoding a protease (Prt) from Streptomyces lividans TK24, was cloned and sequenced. An S. lividans host with plasmid-borne prt secreted 200 micrograms/ml of a 22-kDa Prt into the culture medium. Prt is classified as a metalloprotease since its activity is significantly inhibited by 1,10-phenanthroline or EDTA. The region upstream from prt codes for an incomplete open reading frame (ORF) oriented opposite to prt. This ORF has a strong similarity to a gene family (lysR) whose members regulate the transcription of structural genes required for either biosynthesis or degradation.

Nucleotide and amino acid sequence analysis of the thymidine kinase gene of a bovine encephalitis herpesvirus

The nucleotide and predicted amino acid sequence of the thymidine kinase (TK) gene of N 569, a bovine encephalitis herpesvirus (BEHV), has been determined and compared with those of avian, bovine and other mammalian herpesvirus TK genes. Striking differences were observed between the nucleotide sequence of this BEHV TK gene and those reported for bovine herpesvirus 1 (BHV-1). A total of 118 base changes, 39 base deletions and 14 base insertions were identified relative to the TK sequence of a BHV-1.2a strain, resulting in a net loss of seven residues. Comparison of the TK sequences of BEHV and the BHV-1 Q 3932 strain with that reported for the BHV-1 6660 strain suggested that the latter may have contained sequencing errors. The most significant difference between the BEHV TK sequence and those of BHV-1 strains was the absence of a contiguous stretch of ten codons.

The origin of multiply sigmoid curves of pH-dependence. The partitioning of groups among titration pK values

An acid, HnA, with n ionizing groups is known to have the same titration curve as an equimolar mixture of n hypothetical monobasic acids, whose dissociation constants are known as the 'titration constants' of the real acid. We show that the pH-dependence of any property of HnA is also represented by the sum of one-site titration curves, characterized by these same titration constants. Since one such property is the degree of dissociation of one of the dissociating groups, a fraction of each group shows each of the various titration pK values, so that the group partitions among them. The n groups therefore share the same n titration pK values but differ in the fractions belonging to each. The one H+ ion per molecule that titrates with each pK is thus made up of the fractions, one from each group, that share this pK value. A group may possess a single pK value, in that it contributes virtually all of this pK and almost nothing to the others, only if either (1) in titrates in a different pH range from the other groups or (2) its affinity for H+ is unaffected by their ionization state.

Continuous intravenous infusion fentanyl for sedation and analgesia of the multiple trauma patient

Fentanyl is an attractive agent for analgesia in the emergency department. Its use in this setting has been limited to IV bolus administration. We report successful sedation, muscle relaxation, and analgesia of a multiple trauma patient with fentanyl IV bolus and continuous infusion in the ED.

The epithelial interface with osseointegrated implants

The development of osseointegration has generated interest in the field of intraoral and maxillofacial implantology. There is well documented evidence of a high level of success in achieving osseointegration, using titanium and alumina-ceramic implant materials. Long term retention of intraoral implants appears in part, to be dependent upon the integrity of the epithelium/implant interface. This paper presents the design features of two commercially available systems Intra-Mobile-Zylinder (IMZ) and Tubingen (Frialit), which represent titanium and alumina-ceramic implants respectively, and reviews current knowledge of the nature of the epithelial junction to implant materials and the bacterial flora associated with successful and failing implants. Implant failure may be caused by a site specific infection with a similar ecosystem and bacterial flora to that found in periodontal disease. Care in patient selection and maintenance of a healthy epithelial junction are essential for the long term function of osseointegrated implants.

Performance of occlusin in butt-joint and bevel-edged preparations: five-year results. 4

The five-year findings of a study to compare the performance of restorations of Occlusin (ICI Dental, Macclesfield, UK) in butt-joint and bevel-edged preparations are reported. Ninety-four (79%) of the restorations originally placed were reviewed at five years, 20 restorations (17%) having failed during the study. Initial analysis of the overall results having failed to reveal any significant differences between the five-year performance of the two types of restorations, the results were combined and analyzed by Chi-square tests and step-wise logistic regression. Chi-square analysis indicated that of the independent variables investigated, size of restoration had the greatest effect on clinical performance. Step-wise logistic regression revealed that only four of the eight dependent variables investigated showed significant predictive relationships with the independent variables, the logistic equation for occlusal marginal adaptation being the most complex. The greatest amount of generalized occlusal surface wear tended to be seen in large-sized Class II restorations in molar teeth, with the main factor influencing wear being found to be the type of restoration (Class I or Class II). It is concluded that the performance of restorations of Occlusin has not been found to differ significantly in butt-joint and bevel-edged preparations after five years in clinical service. Step-wise logistic regression has been found to be a useful tool in the analysis of data obtained during the clinical evaluation of a restorative material.

An acetylation method for the quantification of membrane lipids, including phospholipids, polyphosphoinositides and cholesterol

A method for the quantification of membrane lipids by acetylation with [3H]acetic anhydride is described. A standard lipid, labelled with 14C or 32P, is added to the sample and is simultaneously acetylated. The 3H/14C or 3H/32P ratios obtained in the acetylated lipids are proportional to the initial lipid concentration. The method has been used to quantify cholesterol, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in amounts between 2 and 10 nmol.

Identification by immunoblotting of the erythrocyte membrane sialoglycoproteins that carry the Vw and Mur antigens

Immunoblotting of the separated membrane components of MiI erythrocytes with anti-Vw identified a band of Mr 40,000 with a mobility close to that of beta-sialoglycoprotein corresponding to the abnormal alpha-sialoglycoprotein present in MiI cells. A comparison of results obtained when MiIII erythrocytes were immunoblotted with anti-Mur, anti-s and the monoclonal antibody R1.3, indicated that the Mur antigen is located on the abnormal delta-sialoglycoprotein of Mr 36,000 in MiIII erythrocytes. Prior treatment of MiI erythrocytes with neuraminidase resulted in an increase in the intensity of staining of the anti-Vw reactive component. This was consistent with the enhanced reactions observed in haemagglutination tests with neuraminidase-treated erythrocytes. The mobility of the Vw component was reduced when erythrocytes were pre-treated with low concentrations of neuraminidase but increased when higher concentrations of neuraminidase were used.

Analysis of the primary signals required for activation of the mitogenic pathway in murine thymocytes from protein phosphorylation patterns

It has been proposed that phorbol esters and the Ca2+ ionophore A23187 are effective comitogens for some species of lymphocytes because together they mimic the normal secondary signals for cell activation by mitogens that cause phosphatidylinositol 4,5-bisphosphate (PtdInsP2) breakdown (e.g., anti-TCR and anti-Thy-1 antibodies and Con A). To test whether activation of protein kinase C and an increase in [Ca2+]i account for the activation of the mitogenic pathway in murine thymocytes by the mitogens that cause PtdInsP2 breakdown, the two-dimensional phosphorylation patterns generated by the three classes of mitogens (protein kinase C activator, Ca2+ ionophore, and activator of PtdInsP2 breakdown) and by activators of cAMP-dependent kinases have been compared. From the phosphorylation patterns, by which each mitogen could be distinguished reproducibly, it was concluded that: 1) The phosphorylation patterns generated by the mitogens that activate PtdInsP2 breakdown are only slightly affected by the removal of extracellular Ca2+ under conditions that abolish the normal rise in [Ca2+]i and do not therefore depend on the activation of Ca2(+)-dependent protein kinases. In contrast, the phosphorylation pattern generated by A23187 is totally dependent on extracellular Ca2+. 2) Neither A23187 nor the mitogens that activate PtdInsP2 breakdown nor activators of cAMP-dependent kinases caused significant activation of protein kinase C assayed by phosphorylation of the diagnostic proteins 80b and 78a. Consistent with this conclusion, only the phorbol esters or oleoyl acyl glycerol caused translocation of protein kinase C activity from the cytosolic to the membrane fraction. 3) Neither A23187 nor the mitogens that cause PtdInsP2 breakdown activated cAMP-dependent kinases. Taken together the data imply that the mitogens that cause PtdInsP2 breakdown must generate an additional, independent primary mitogenic signal. It is suggested that this signal may be the activation of tyrosine kinases (e.g., p56lck) via the TCR and working hypotheses for effective combinations of primary mitogenic signals that will activate DNA synthesis are developed.

Analysis of the primary signals required for activation of the mitogenic pathway in murine thymocytes from protein phosphorylation patterns

It has been proposed that phorbol esters and the Ca2+ ionophore A23187 are effective comitogens for some species of lymphocytes because together they mimic the normal secondary signals for cell activation by mitogens that cause phosphatidylinositol 4,5-bisphosphate (PtdInsP2) breakdown (e.g., anti-TCR and anti-Thy-1 antibodies and Con A). To test whether activation of protein kinase C and an increase in [Ca2+]i account for the activation of the mitogenic pathway in murine thymocytes by the mitogens that cause PtdInsP2 breakdown, the two-dimensional phosphorylation patterns generated by the three classes of mitogens (protein kinase C activator, Ca2+ ionophore, and activator of PtdInsP2 breakdown) and by activators of cAMP-dependent kinases have been compared. From the phosphorylation patterns, by which each mitogen could be distinguished reproducibly, it was concluded that: 1) The phosphorylation patterns generated by the mitogens that activate PtdInsP2 breakdown are only slightly affected by the removal of extracellular Ca2+ under conditions that abolish the normal rise in [Ca2+]i and do not therefore depend on the activation of Ca2(+)-dependent protein kinases. In contrast, the phosphorylation pattern generated by A23187 is totally dependent on extracellular Ca2+. 2) Neither A23187 nor the mitogens that activate PtdInsP2 breakdown nor activators of cAMP-dependent kinases caused significant activation of protein kinase C assayed by phosphorylation of the diagnostic proteins 80b and 78a. Consistent with this conclusion, only the phorbol esters or oleoyl acyl glycerol caused translocation of protein kinase C activity from the cytosolic to the membrane fraction. 3) Neither A23187 nor the mitogens that cause PtdInsP2 breakdown activated cAMP-dependent kinases. Taken together the data imply that the mitogens that cause PtdInsP2 breakdown must generate an additional, independent primary mitogenic signal. It is suggested that this signal may be the activation of tyrosine kinases (e.g., p56lck) via the TCR and working hypotheses for effective combinations of primary mitogenic signals that will activate DNA synthesis are developed.

The information-loss model: a mathematical theory of age-related cognitive slowing

A model of cognitive slowing is proposed with the following assumption: Information is lost during processing, processing occurs in discrete steps with step duration inversely related to the amount of information currently available, and the effect of aging is to increase the proportion of information lost per step. This model correctly predicts a positively accelerated relation between latencies of older and younger adults and provides a unified account of the effects of task complexity, practice, speed-accuracy tradeoffs, and fluctuations in individual performance. Strong support for the thesis that cognitive slowing is global, and not localized in specific age-sensitive components, is provided by the fact that the model accurately predicts the latencies of older adults on the basis of those of younger adults, without regard to the nature of the task, across a latency range of nearly 2 orders of magnitude.

The location and nucleotide sequence of the thymidine kinase gene of bovine herpesvirus type 1.2

On the basis of their restriction endonuclease digestion patterns, four Australian bovine herpesvirus type 1 (BHV-1) isolates were classified as belonging to the BHV-1.2a subtypes. The thymidine kinase (TK) genes of all four BHV-1.2a isolates were located on a 3.5 kb SalI restriction fragment. This is in contrast to North American and European BHV-1.1 isolates whose TK genes are contained on a 2.6 to 2.8 kb SalI fragment. The restriction fragments containing the TK genes were cloned into phagemid vectors and their sequences determined using the dideoxynucleotide chain termination method. The BHV-1.2a isolates possessed identical TK gene sequences, which differed from previously published TK sequences for the LA and 6660 BHV-1.1 strains. In addition to five single base alterations, there were six separate base insertions which resulted in two major frameshifts which spanned an area of 72 amino acids or 20% of the expressed TK gene product. The predicted amino acid sequence exhibited a higher degree of similarity to other herpesvirus TKs, suggesting that previously published TK gene sequences may have been incorrect. The present nucleotide sequence and corresponding amino acid composition reinforces previous observations concerning regions of herpesvirus TK amino acid conservation and should assist in future studies into the evolution and functional domains of herpesvirus TKs.

Processing speed and mental retardation: deadline procedures indicate fixed and adjustable limitations

Brewer and Smith (1984) showed that control mechanisms mediating speed-accuracy regulation contribute to retarded-nonretarded differences in processing speed, with poorly controlled trial-to-trial RT adjustments underlying the greater RT variability of retarded individuals. In Experiment 1, response deadlines controlled processing time, thus minimizing the influence of such control mechanisms. The obtained speed-accuracy relations showed that retarded subjects were unable to match nonretarded subjects' accuracy when responding as rapidly, thus indicating structural limitations on processing speed. The results of Experiment 2 showed, however, that significant adjustments to retarded subjects' processing speed--exceeding those produced by practice--are achievable. Extended training at a short deadline led to tighter control of RT adjustments, with substantial improvements in mean RT when subjects transferred to a self-paced RT task.

Use of 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) in the measurement of free intracellular calcium in the brain by 19F-nuclear magnetic resonance spectroscopy

We have applied the 19F-nuclear magnetic resonance (NMR) calcium indicator 1,2-bis(2-amino-5-fluoro-phenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) to the measurement of the free intracellular calcium concentration [( Ca2+]i) in superfused brain slices. A mean +/- SD control value of 380 +/- 71 nM (n = 18) was obtained at 37 degrees C using 2.4 mM extracellular Ca2+. Subcellular fractionation studies using [3H]5FBAPTA showed that after loading of its tetraacetoxymethyl ester, approximately 55% was de-esterified, with the other 45% remaining as the tetraester bound to membranes. Of the de-esterified 5FBAPTA, greater than 90% was in the cytosolic fractions, with less than 1% in the mitochondria or microsomes. The NMR-visible de-esterified 5FBAPTA slowly disappeared from the tissue with a t1/2 of 4 h. A time course after loading confirmed that the calculated [Ca2+]i was constant over a 5-h period, although the scatter of individual results was +/- 20%. The [Ca2+]i was increased by a high extracellular K+ concentration ([K+]e), by a low extracellular concentration of Na+, and by the calcium ionophore A23187. On recovery from high [K+]e, the [Ca2+]i "overshot" to values lower than the original control value. The [Ca2+]i was surpisingly resistant to changes in extracellular Ca2+ concentration.

Assessing sincerity of effort in maximal grip strength tests

Injuries to the upper extremities sometimes result in a loss of work capacity. One of the methods for measuring this loss of work capacity is the grip test. Such measurements may be compromised by an insincere effort (faking) by the subject. Smith et al. (Am J Phys Med Rehabil 1989;68:73-80) developed a protocol to identify sincere and faking efforts with the use of a modified dynamometer. The present investigation was designed to evaluate the applicability of the previously developed protocol to subjects with hand injuries. The investigators also compared the force-time characteristics for contractions at different percentages of maximum (100, 75, 50, and 25%). Sixty subjects (30 male and 30 female) were tested during two sessions while performing both faking and sincere efforts. The five discriminators previously developed were found to be good detectors for both noninjured and injured hands and provided the basis for cutoff values for the five discriminators. Single discriminator prediction gave at best an 85% faking detection rate (by using D3) for men and a 79.2% detection rate (by using D5) for women. Better results were obtained, when a multiple variable prediction was used. It can be concluded that the protocol developed by Smith et al. for detection of an insincere effort can be used successfully with persons who have sustained upper extremity injuries. Furthermore, sincere and faking grip strength "maxima" can be correctly identified across a wide range of applied force levels.

Transdermal iontophoresis of gonadotropin releasing hormone (LHRH) and two analogues

Gonadotropin releasing hormone (GnRH), as well as an antagonist [Ac-D2Nal,1 D4ClPhe,2 D3Pal,3 NicLys,5 DNicLys,6 ILys,8 DAla10] GnRH.HOAc (1) and a superagonist [DTrp6, Pro9-NHEt]GnRH (2), have been electrochemically driven across excised hairless mouse skin. Determined by HPLC analysis, the delivery rate from aqueous solution into isotonic saline at 0.5 mA cm-2 was as high as 19 nM cm-2 h-1 for 2. Because of its insolubility in water, analogue 1 could only be delivered from an acidic donor solution. Analogue 2 was also delivered in pulsatile fashion using current on/off cycles. For all three peptides, passive transport was negligible and stability is evident when in contact with the stratum corneum. Slow metabolism occurs when GnRH contacts the dermal side of hairless mouse skin.

Activities of 3'-azido-3'-deoxythymidine nucleotide dimers in primary lymphocytes infected with human immunodeficiency virus type 1

The relative antiviral potencies of five nucleotide heterodimers of 3'-azido-3'-deoxythymidine (AZT), 3'-azido-3'-deoxythymidilyl-(5',5')-2'-3'-dideoxy-5'-adenylic acid (AZT-P-ddA), 3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-dideoxy-5'-inosinic acid (AZT-P-ddI), and the corresponding 2-cyanoethyl congeners AZT-P(CyE)-ddA and AZT-P(CyE)-ddI, were determined in primary human peripheral blood mononuclear cells infected with human immunodeficiency virus type 1. The homodimer 3'-azido-3'-deoxythymidilyl-(5',5')-3'-azido-3'-deoxythymidilic acid (AZT-P-AZT) was also included for comparison. The potencies of the compounds were AZT-P-ddA greater than or equal to AZT-P-ddI greater than AZT-P(CyE)-ddA greater than or equal to AZT-P(CyE)-ddI greater than or equal to AZT greater than AZT-P-AZT. Whereas AZT-P-ddA and AZT-P-ddI had in vitro therapeutic indices greater than that of AZT, the homodimer of AZT had a low therapeutic index. AZT-P-ddI exhibited the lowest toxicity in peripheral blood mononuclear, Vero, or CEM cells. Combination studies between AZT and 2',3'-dideoxyinosine (ddI) at nontoxic concentrations indicated a synergistic interaction at a drug ratio of 1:100. At higher ratios (1:500 and 1:1,000), the interactions were synergistic only at concentrations that produced up to 75% virus inhibition. At higher levels of antiviral effects, this combination was antagonistic, as determined by the multiple drug effect analysis method. AZT-P-ddI was about 10-fold less toxic than AZT to human granulocyte-macrophage progenitor cells. However, no significant difference was apparent when the compounds were evaluated against cells of the erythroid lineage. The greater antiviral activity and lower toxicity of this compound could not be attributed to the extracellular decomposition of the dimer in media at physiological temperature and pH. However, in acidic solutions, AZT-P-ddI decomposed in a pH-dependent manner. Advanced preclinical studies with this heterodimer of two clinically effective antiretroviral agents should be considered.

Biomechanics of crosscountry skiing

The mechanics of crosscountry skiing involve a complex interaction between the kinematic characteristics of the movement patterns and the kinetic relationships driving the motion. Crosscountry skiing techniques have been the subject of some biomechanical research, primarily involving the traditional diagonal stride technique. In the 1980s, skiers have developed several new approaches to moving across snow. These skating techniques rely on the generation of force from ski placements at an angle to the forward direction creating propulsive force while the ski slides forward. Biomechanical analysis of the crosscountry techniques has developed from rather simple 2-dimensional kinematic descriptions of diagonal stride to complex measurement of skating forces and 3-dimensional motion. The combined determination of forces and resultant motion has perhaps the most promise for practical application in assessments of equipment and technique. The relationship of the kinematic characteristics of skiing to the forces involved have received preliminary study but substantial gains in understanding will be necessary before approaches to optimising a skier's technique are plausible.

Identification and immunochemical characterization of the human erythrocyte membrane glycoproteins that carry the Xga antigen

When the membrane components of Xg(a+) erythrocytes were separated by electrophoresis and immunoblotted with an anti-Xga of human origin, two diffuse bands of approximate Mr 22,000-25,000 and 26,500-29,000 were stained. These reactive components were not evident in membranes from proteinase-treated Xg(a+) erythrocytes. Neuraminidase treatment of erythrocytes before immunoblotting resulted in one diffuse Xga-reactive band, the leading edge of which had a slightly increased mobility corresponding to a decrease in Mr of approx. 1500. These results suggest that the membrane components that carry Xga are sialoglycoproteins. A genetic relationship exists between Xga and the antigen recognized by the monoclonal antibody 12E7. An immunochemical comparison of the structures that carry the Xga and 12E7 antigens demonstrated that they differ in Mr and in the way in which they are modified by neuraminidase. This is in accord with evidence that Xga and 12E7 are the products of two separate structural loci.

The immediate or delayed replacement of teeth by permucosal intra-osseous implants: the Tübingen implant system. Part 2: Surgical and restorative techniques

The previous paper emphasised the importance of case selection in determining success in the use of the Tübingen implant system. Adherence to strict clinical techniques has an equally important influence on implant success and failure. This paper describes the surgical and restorative techniques involved in the use of the Tübingen implant and comments on the authors' initial experiences with this system.

The influence of breed and sex on the incidence of mortalities and skin tears in broiler carcasses

The effects of nutrition, breed and sex on the incidence of mortalities and of skin tears on broiler carcasses were studied. Both sexes of 2 breeds, Hubbard and Ross, were given 4 dietary treatments consisting of a normal level of vitamin and mineral premix plus 300 ppm furazolidone, twice normal premix inclusion level plus 300 ppm furazolidone, a normal level of vitamin and mineral premix, and twice normal mineral premix inclusion level. A coccidiostat containing the active ingredient halofuginone was included at 6 ppm, twice the recommended dosage. Starter, grower and finisher diets were fed respectively up to Day 20, Day 30 and Day 48. Group growth performances, mortalities and the incidence of torn skin were monitored on both the live birds and carcasses. The effect of the different nutritional treatments on skin tears was not significant (P = 0.9533), as was the breed effect (P = 0.0547). However, the effect of sex was significant (P = 0.0044), the incidence in hens being higher. Mortalities among the Hubbard were significantly greater than among the Ross (P = 0.0001). Hens showed a slightly higher mortality rate than roosters, tending towards significance at the 5% level (P = 0.0554).

The immediate or delayed replacement of teeth by permucosal intra-osseous implants: the Tübingen implant system. Part 1. Implant design, rationale for use and pre-operative assessment

No single implant system is applicable to all clinical problems which may be treated with implants. Clinicians who wish to develop expertise in the field of dental implantology should decide which clinical situations they wish to treat with implants and then receive an appropriate level of instruction in the use of systems which have been shown, in refereed literature, to be successful in the treatment of such problems. The Tübingen implant system has been in clinical use for more than 13 years, following preliminary basic research and animal studies, and is supported by an extensive literature. It is applicable primarily to the immediate or delayed replacement of individual teeth which are subsequently to be restored with a post crown. It may also be used in other situations, such as in combination with bridge restorations. This is the first of two papers which describe in detail the range of applications, patient selection and assessment, and the surgical and restorative techniques involved in its use.

Assessing sincerity of effort in maximal grip strength tests

The measurement of maximum hand grip strength in ergonomic or clinical settings has been a useful means of assessing physical characteristics, progress in rehabilitation and degree of disability in upper extremity injuries. The validity of the peak forces observed in such measurements is compromised by the requirement of subject cooperation in giving a maximum effort. Thus, an easily administered analysis of subject sincerity would improve this basic strength-testing tool. Several variables were developed for the discrimination of faking (submaximal) from sincere (maximal) grip contractions. A microcomputer-based grip force data collection system was assembled in which analog output from a Jamar hand dynamometer was sampled at 200 Hz and digitally analyzed. A total of 43 normal subjects (20 male, 23 female) were tested under sincere and faking conditions (three trials of each condition for each hand). The force-time curves of each trial were analyzed for peak and average forces and force variability. From these basic parameters five discriminator variables were developed. The frequency distribution of the sincere values for each of these variables was used to determine a criterion value for discrimination of sincere from faking trials. The five discriminators correctly detected 95.0, 92.5, 100, 100 and 97.5% of the male faking trials. Female faking was less successfully detected: 59.7, 52.2, 78.3, 71.7 and 87.0% correct detection resulted for the variables (with a 95% confidence level of correctly identifying sincerity). Multiple variable predictions improved the female faking detection up to 93.5% with little apparent decrement in sensitivity to sincerity identification.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial characterisation of the human erythrocyte antigen Pta

Ghosts were prepared from erythrocytes positive for the rare blood group antigen Pta. Immunoblotting of the solubilised ghosts with anti-Pta located the antigen on a band with an Mr of 31,600, about 1,100 higher than that of sialoglycoprotein gamma. Binding to the same band was also observed when cytoskeleton preparations from Pt(a+) erythrocytes were immunoblotted with the antibody. Haemagglutination and immunoblotting experiments were consistent in demonstrating that the Pta antigen is not inactivated by treatment of intact erythrocytes with neuraminidase or trypsin but is destroyed by treatment with alpha-chymotrypsin, papain or pronase. The data indicate that the Pta antigen is carried on a 'new' erythrocyte membrane protein.

Ca2+ transient, Mg2+, and pH measurements in the cardiac cycle by 19F NMR

19F NMR indicators have been used to measure the free cytosolic cation concentrations ([Mn+]i, where M is the atomic symbol and n is the value of the charge) of Ca2+, H+, and Mg2+ in perfused ferret hearts. The [Ca2+]i transient, cytosolic pH (pHi), and [Mg2+]i have also been followed at 16 phases in the cardiac cycle in hearts paced at 1.25 Hz at 30 degrees C. The initial [Ca2+]i rose rapidly after a 50-ms delay, was maximal at greater than 1.5 microM after 150 ms, and declined thereafter to the initial concentration. In contrast, no significant changes in pHi (pH 7.03 +/- 0.08) or [Mg2+]i (1.2 +/- 0.1 mM) were detected in the cycle. A decrease in developed pressure when the [Ca2+]i indicator (but not the pHi or [Mg2+]i indicator) was loaded into hearts was substantially reversed by the addition of 50 microM ZnCl2 to the perfusion medium. The Zn2+ was taken up into the myoplasm and displaced Ca2+ bound to the indicator, a symmetrically substituted difluoro derivative of 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA), as evidenced by the appearance of the Zn-5FBAPTA resonance. The decrease in developed pressure caused by 5FBAPTA, therefore, may be due to its Ca2+ buffering effect on the myoplasm. By coloading hearts with the [Ca2+]i and pHi indicators, simultaneous measurement of several [Mn+]i was demonstrated, which should provide a useful addition to the methods available to monitor cardiac function and pharmacology.

Age, variability, and speed: between-subjects diversity

Two independent data sets were selected to examine the interrelations among reaction time (RT), between-subject variability or diversity (SD), and age. In both data sets, a strong correlation between RT and SD was obtained. This strong correlation was not affected when age was controlled in a partial correlation analysis. On the other hand, a weaker but significant correlation was obtained between age and SD. This correlation was eliminated when RT was controlled in a partial correlation analysis. Our analyses of the two data sets also indicated that the relation between RT and SD is identical for both young and elderly groups. Thus, the greater diversity often observed in performances of older groups is a direct consequence of slowing, rather than an independent effect of advancing age.

Comparison between the cellobiose/mannitol and 51Cr-labelled ethylenediaminetetra-acetate absorption tests in the detection of coeliac disease

1. The cellobiose/mannitol and 51Cr-labelled ethylenediaminetetra-acetate (51Cr-EDTA) absorption tests have been compared with respect to their ability to detect altered intestinal permeability in coeliac disease. 2. In patients with clinically proven coeliac disease, 13 out of 14 (93%) had abnormal urinary cellobiose/mannitol ratios, while only five out of 12 (42%) had abnormal urinary recoveries of 51Cr-EDTA. Thus, the cellobiose/mannitol absorption test is more sensitive in recognizing coeliac disease and this difference was significant (P less than 0.02). 3. Possible reasons for this difference in the sensitivity of the two absorption tests are discussed.

Orthodontic bonding to porcelain--bond strength and refinishing

Glazed porcelain surfaces are not amenable to resin penetration for orthodontic bonding. The aims of this study were to evaluate (1) the bond strengths of two orthodontic composite materials to treated porcelain surfaces, (2) the effect of thermocycling, and (3) the porcelain surfaces after refinishing. Sixty glazed porcelain disks were assigned to three surface treatment groups: Silane (S), roughening and silane (RS), and roughening (R). The acid-etched enamel surfaces of 20 extracted teeth served as a control group. Ten specimens in each group were bonded with either Concise or System 1. They were stored in water at 37 degrees C or thermocycled 8 degrees to 45 degrees C. Shear bond strength was tested with an Instron testing machine (0.05 cm/min). Analysis of variance showed that the four surface treatment groups and the two composite materials produced significantly different bond strengths (P less than 0.01 and P less than 0.05, respectively). The effect of thermocycling was not significant (P greater than 0.05). Acid-etched enamel/Concise produced the highest mean bond strength (17.4 MN/m2). This was significantly greater (P less than 0.05) than the mean bond strengths of S/Concise (11.1), RS/System 1 (8.6), RS/Concise (8.1), and enamel/System 1 (7.8). The latter four mean bond strengths in turn were significantly greater (P less than 0.05) than S/System 1 (2.5), R/Concise (2.1), and R/System 1 (1.8). Of the four refinishing systems evaluated, all produced smooth surfaces but were unable to reproduce a glazed appearance. Roughening of porcelain and the silane treatment achieve bond strengths that should be clinically successful.(ABSTRACT TRUNCATED AT 250 WORDS)

Caffeine reduction as an adjunct to anxiety management

A reduction in tea and coffee drinking is popularly advocated for the relief of tension and anxiety symptoms, and it was decided to collect empirical data on this matter in the course of normal clinical practice. It was found that patients who made substantial reductions in caffeine drinking also made the greatest improvements in anxiety, irritability, sleep disturbance, headaches and abdominal symptoms. The methodology leaves an ambiguity in the interpretation of this result, but the data provide a useful basis for the design of further studies.

[Energy and protein requirements of dogs and cats]

The latest research findings published on the energy and amino acid requirements of dogs and cats are reviewed. Special attention was paid to research results, applicable to working dogs, which have not as yet been incorporated into the recommended requirement standards of the National Research Council.

Design and properties of a fluorescent indicator of intracellular free Na+ concentration

We have recently described a cryptand structure, FCryp-1, with appropriate properties for an indicator of intracellular free Na+ concentration using the 19F-n.m.r. chemical shift of the incorporated 5FBAPTA [1,2-bis-(2-amino-5-fluorophenoxy)ethane-NNN'N'-tetra-acetic acid] reporter group to measure the free cytosolic Na+ concentration [( Na+]i) [Smith, Morris, Hesketh and Metcalfe (1986) Biochim. Biophys. Acta 889, 82-83]. FCryp-1 carries four carboxylate groups to confer aqueous solubility and the indicator is membrane-permeant when the carboxyls are esterified with acetoxymethyl ester groups. Here we describe the synthesis of FCryp-2 to provide a fluorescent indicator of [Na+]i. FCryp-2 retains the parent tribenzo (2:2:1) cryptand structure of FCryp-1, in which the benzenoid ring at C-21 in FCryp-1 is replaced by an indole derivative which acts as the fluorophor in FCryp-2. With excitation at 340 nm, FCryp-2 gives an emission maximum at 460 nm in the absence of Na+ which shifts to 395 nm when FCryp-2 is saturated with Na+, with an isosbestic point at 455 nm. The apparent dissociation constant of FCryp-2 in a buffer solution of 100 mM-KCl/20 mM-KH2PO4/K2HPO4, pH 7.0, at 37 degrees C is 6.0 mM and the free Na+ concentration can be measured either from the calibrated fluorescence intensity at 395 nm, which increases 25-fold when Na+ is bound to FCryp-2, or from the ratio of fluorescence intensities at 395 nm and 455 nm. The measurement of free [Na+] by either method is unaffected by K+, Ca2+ or Mg2+ in the normal intracellular concentration ranges. Free [Na+] measurements by the ratio method are unaffected by pH from 6.6 to 7.6.

Age, variability, and speed: Between-subjects diversity

Two independent data sets were selected to examine the interrelations among reaction time (RT), between-subject variability or diversity (SD), and age. In both data sets, a strong correlation between RT and SD was obtained. This strong correlation was not affected when age was controlled in a partial correlation analysis. On the other hand, a weaker but significant correlation was obtained between age and SD. This correlation was eliminated when RT was controlled in a partial correlation analysis. Our analyses of the two data sets also indicated that the relation between RT and SD is identical for both young and elderly groups. Thus, the greater diversity often observed in performances of older groups is a direct consequence of slowing, rather than an independent effect of advancing age.