Allelic imbalance at the DNA mismatch repair loci, hMSH2, hMLH1, hPMS1, hPMS2 and hMSH3, in squamous cell carcinoma of the head and neck.

BACKGROUND: Squamous cell carcinoma of the head and neck (SCCHN) is one of the 10 most frequently occurring cancers in the world. Defective mismatch repair, as exhibited by the phenomenon of microsatellite instability, has been observed in SCCHN although no reports of mismatch repair gene mutations or altered protein expression have been published. In a variety of microsatellite instability (MSI) positive cancers where mutations in the mismatch repair (MMR) genes were not observed, allelic imbalance at the loci of the MMR genes was prevalent. OBJECTIVE: To investigate whether allelic imbalance at the MMR genetic loci contributes to the development of SCCHN. MATERIALS AND METHODS: 35 matched normal/tumour SCCHN pairs were studied using 29 microsatellite markers located within and adjacent to six known DNA mismatch repair genes. In addition, mutational analysis and protein expression of hMSH2 and hMLH1 were investigated. RESULTS AND CONCLUSIONS: We demonstrated that 36 and 17% of the analysed SCCHN specimens exhibited allele imbalance at the hMLH1 and hMSH3 genetic loci, respectively. Allelic instability at these two loci was found to be correlated with the MSI status of the SCCHN tumours. Allelic instability was found to be uncommon at the other MMR gene loci analysed. One mutation was found in hMSH2 and none in hMLH1 in this series of tumours. 23 of 24 (96%) of the examined SCCHN tumours showed reduced expression of either hMSH2 or hMCH1 genes. Allelic instability in the MMR genes, hMLH1 and hMSH3, is proposed to be involved in the aetiology of SCCHN tumours.

Elimination and biochemical responses to intravenous alendronate in postmenopausal osteoporosis.

Postmenopausal women with established vertebral osteoporosis were studied for 2 years to determine the terminal elimination half-life and the duration of response to treatment with intravenous alendronate (30 mg) given over 4 days. The urinary excretion of alendronate followed a multiexponential decline. Approximately 50% of the total dose was excreted over the first 5 days, and a further 17% was excreted in the succeeding 6 months. Thereafter, there was a much slower elimination phase with an estimated mean terminal half-life of greater than 10 years (n = 11). Urinary excretion of hydroxyproline and calcium decreased significantly from pretreatment values by day 3, reaching a nadir by 1 week (40% and 67% decrease, respectively). Thereafter, hydroxyproline remained suppressed for the following 2 years. In contrast, urinary calcium excretion returned gradually toward pretreatment values over the first year and during the second year was comparable to pretreatment values. Serum activity of alkaline phosphatase activity decreased over 3 months (23% reduction), increased gradually thereafter, and returned to pretreatment values at month 24. Bone mineral density measured at the spine increased by approximately 5% during the first year and remained significantly higher than pretreatment values at 2 years. We conclude that a short course of high doses of intravenous alendronate is associated with a prolonged skeletal retention of the agent. This open study also suggests that this regimen has a sustained effect on bone turnover persisting for at least 1 year.

Effects of tryptophan supplementation to a maize-based diet on lipid metabolism in laying hens.

1. Experiments were conducted with laying hens to determine the effects of supplementing 0, 1.0, 2.0 and 3.0 or 4.0 g trp/kg diet to a maize and soyabean meal-based laying ration (basal tryptophan = 1.66 g/kg) on tissue lipid concentrations. 2. Plasma cholesterol, triglycerides and nonesterified fatty acids were increased by supplementing the diet with 1.0 g trp/kg diet and decreased with 3.0 or 4.0 g trp/kg diet. A significant quadratic effect of supplemental tryptophan was observed on plasma lipids in most cases. The observed effects diminished with time. No consistent changes were observed in plasma glucose concentrations. 3. Total liver lipids were reduced by supplemental tryptophan at all concentrations.

Effect of tryptophan supplementation on aflatoxicosis in laying hens.

Two experiments were conducted to determine the relationship of supplemental Trp on liver fat accumulation and egg production during aflatoxicosis in laying hens. In Experiment 1, two levels of Trp (0 and 2,000 ppm; basal = .16% Trp) and two levels of aflatoxin (AFLA) (0 and 10 ppm) were supplemented to a complete layer ration. In Experiment 2, a third level of AFLA (5 ppm) was added to the design. Single Comb White Leghorn hens (58 and 68 wk old) were fed the diets for 3 wk for Experiments 1 and 2, respectively. Henday production and egg weights were measured daily. Feed intake was measured weekly. Liver weights, liver moisture, and liver total lipids were determined at the end of each trial. In Experiment 1, supplemental Trp by itself caused a significant (P less than .01) reduction in total liver lipids compared to the controls (no Trp or AFLA). Adding trp and AFLA increased total liver lipids and caused a significant (P less than .05) decrease in egg production compared with adding AFLA alone. Total liver lipids were 41.1, 32.8, 54.8, and 62.4% (dry weight basis) for 0 Trp:0 AFLA, 2,000 Trp:0 AFLA, 0 Trp:10 AFLA, and 2,000 Trp:10 AFLA, respectively. Similar results were observed in Experiment 2. It was concluded that supplemental Trp by itself caused a reduction in total liver lipids, but when supplemented to a diet containing AFLA, Trp caused an increased severity of lesions associated with aflatoxicosis in layers.

Influence of method of model fitting and gender on estimated parameters for the relationship between starvation heat production and body size in the domestic fowl.

The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for domestic fowl was examined with compiled calorimetric data for 294 fowls (Johnson and Farrell, 1985). Linear regression analyses using ordinary least squares methods were performed before and after transformation of the data to a logarithmic scale (base = 10). Coefficients of determination (R2) were similar for untransformed and log-transformed data (R2's = .56 and .53, respectively). The slopes for untransformed data of males and females were different (P less than 0.033). When the model parameters for: SHP = b0 Wb1 were derived from log-transformed data, there were no significant differences in exponents for males vs. females (P greater than .95). However, when the coefficients were estimated using non-linear regression techniques, a difference was detected at the level of P = 0.072. It was determined that there is no advantage in describing the relationship of SHP as a non-linear function of W, nor is it appropriate to express physiological variables as a ratio of weight raised to some mass exponent without statistical justification. Using W or W2 as a covariable for the statistical analysis of physiological data would produce equally acceptable determinations of significance.

The influence of dietary tryptophan on broiler chick growth and lipid metabolism as mediated by dietary protein levels.

Three experiments were conducted to determine how dietary protein and tryptophan influence the lipid metabolism of growing broiler chicks. A diet-dilution method (corn-corn gluten meal-gelatin summit/corn starch basal) was used in three factorial experiments. Various levels of protein and tryptophan were fed in each experiment: protein from 16 to 28% and tryptophan from .34 to 2.74% of protein. Gain was maximized when the dietary levels of tryptophan were .83 +/- .03, 77 +/- .04, 77 +/- .05, and .78 +/- .05% of the protein for 16, 20, 24, and 28% dietary protein, respectively. The requirement estimates for feed efficiency and gain were similar. Liver lipids significantly decreased as the level of dietary tryptophan increased at each protein level (P less than .0001). Dietary tryptophan did not significantly alter the concentration of total plasma lipid in the chicks or in the carcass lipid content (P greater than .2399). Tryptophan supplementation significantly increased the concentration of plasma linoleic acid and plasma free tryptophan. The requirement of the chicks for tryptophan was estimated to be .80 +/- .01% of the dietary protein for the growing chick. Increased liver lipid and decreased plasma tryptophan are diagnostic lesions suggesting a tryptophan deficiency.

Galactose as a regulatory factor of its own metabolism by rat liver.

As part of a series of studies to assess the regulation of hepatic galactose-metabolizing enzymes, galactokinase, galactose-1-phosphate uridyltransferase, and UDPgalactose-4-epimerase, the effect of feeding a high galactose-containing diet to normal adult and pregnant female rats was examined. Sixteen days of galactose exposure of adult virgin females produced a different response in the specific activity of each of the enzymes, that of galactokinase being lower, transferase higher, and epimerase transiently elevated. Galactose feeding increased the specific activity of transferase in pregnant rat liver above the elevated level that already exists in the pregnant state but failed to influence the enzyme of the developing fetal liver. Galactose added to liver homogenates did not activate transferase. The increased activity in liver of adult, fed animals was not associated with a change in isoenzyme patterns examined by isoelectric gel electrophoresis but was characterized on kinetic analysis by an increase in Vmax for UDPglucose. The changes in enzyme specific activity in liver of animals fed galactose appear to have physiologic significance because hepatocytes isolated from galactose exposed livers take up more galactose and convert more to glucose and lactate than cells from control animals.

Activity of hepatic galactose-metabolizing enzymes in the pregnant rat and fetus.

The sp act of hepatic galactose-metabolizing enzymes, galactokinase, galactose-1-phosphate uridyltransferase, and uridine diphosphate-4-epimerase were measured in female rats during pregnancy and lactation as well as in fetuses and pups after parturition. Sp act for transferase and epimerase in pregnant rat liver are about 50% higher than that of virgin females, and with the increase in organ size during pregnancy the total hepatic activity is double that of nonpregnant animals. Galactokinase activity decreases somewhat during pregnancy, but total activity is 25% higher than in virgin liver. A Michaelis-Menten kinetic analysis of liver transferase indicates an increase in the maximum velocity of the reaction without a change in Km. Isoelectricfocusing on a high-resolution IEF gel demonstrated similar isozyme patterns. The sp act of the fetal liver enzymes increase to about twice that of the maternal tissue, but total activities are low due to the very small fetal liver size. Sp act of these enzymes in maternal liver fall after delivery, but sp act of galactokinase and transferase are programmed to increase in liver of the growing neonatal animals, reaching levels almost 5-fold higher than found in nonpregnant adult liver. An understanding of factors contributing to the enhanced transferase activity of the liver of pregnant and neonatal rats may contribute to possible ways of augmenting the residual transferase activity of patients with transferase-deficient galactosemia as a therapeutic strategy.

The comparative effects of azathioprine and cyclosporin on some gingival health parameters of renal transplant patients. A longitudinal study.

The periodontal health of 24 adult renal transplant patients was investigated in a longitudinal study. Post-transplant patients were receiving either azathioprine or cyclosporin to prevent graft rejection. No significant difference (P greater than 0.05) was observed for plaque scores on gingival inflammation, either between treatment groups or throughout the investigation period. However, patients on cyclosporin therapy had significantly more gingival hyperplasia and probing sites greater than 3 mm than those on azathioprine (P less than 0.05). In the cyclosporin group, a significant increase in hyperplasia and probing sites greater than 3 mm was observed at 3 and 6 months post-transplant. A significant correlation (rs = 0.55, P less than 0.05) was observed between mean plasma concentrations of cyclosporin throughout the 6-month investigation period and the increase in gingival hyperplasia. The finding from this study would suggest that azathioprine has no unwanted effects on the periodontal health of post-renal transplant patients. Cyclosporin therapy caused an increase in gingival hyperplasia, which may be related to plasma concentrations of the drug.

Influence of choline and sulfate on copper and toxicity and substitution of and antagonism between methionine and copper supplements to chick diets.

Studies were conducted to determine if the deleterious affects on chick growth of the primary antagonism between methionine and copper involves the homocysteine moiety or labile methyl group of methionine. A .1% choline supplement resulted in performance response similar to that of a .2% L-methionine supplement in the absence but not in the presence of 500 mg/kg copper from cupric sulfate. Similar results were observed when the levels of methionine and choline were doubled. Sulfate, with or without choline, had little effect in the presence of cupric sulfate. When cupric acetate was used instead of cupric sulfate, a small but nearly significant (P = .08) response to potassium sulfate was observed. Maximum performance with .29% supplemental methionine and 188 mg/kg Cu was predicted from a response surface analysis. The methionine requirement was increased by feeding copper. However, the increase in methionine requirement was accompanied by an improvement in growth rate and feed efficiency. This may explain why levels used of methionine and total sulfur-containing amino acids appear to be higher under field conditions (with pharmacological levels of copper) than in laboratory conditions (without pharmacological levels of copper). The primary antagonism between methionine and copper involves the homocysteine moiety, not the labile methyl groups.

Comparison of three nonlinear regression models for describing broiler growth curves.

Three general growth models (Logistics, Gompertz and Saturation Kinetics) were compared for describing growth of broilers. Accuracy of fit, case of use and interpretation of data were used to compare the models. Data from a broiler feed restriction study was used to illustrate the parameter differences between the models. All three models accurately described the growth of the birds from the different experimental treatments based on coefficients of determination greater than or equal to .966. The Saturation Kinetics model proved to be the least accurate based on examination of residual values but still had a high association to the actual data. Linear regression applied to short intervals of the growth curve also proved to be an accurate means of interpreting growth rates.

The use of biofeedback techniques in occupational therapy for persons with chronic pain.

The use of biofeedback in occupational therapy to aid the person with chronic pain in the resumption of his daily functional activities is discussed. The chronic pain syndrome and how it disrupts performance of activities is examined, as well as occupational therapy strategies for assessment and treatment using biofeedback, and indications for evaluating treatment outcomes. The authors assume readers have basic familiarity with biofeedback theory, equipment and its operation.

Galactose and glucose metabolism in the isolated perfused suckling and adult rat liver.

The development of the technique for the perfusion of the immature liver has enabled us to characterize metabolic differences in carbohydrate metabolism in the suckling versus adult rat livers. Livers of fasted suckling and adult rats were perfused with 4 mM galactose or 4 mM glucose. Galactose uptake was the same for both age groups during the first 35 min. The adult liver maintained the initial rate of uptake after this period while the immature liver began to take up galactose more rapidly. By the end of the experimental period, on a weight basis, uptake by the young liver was three times that of the adult. Analysis of the livers at the end of the 90 min perfusion showed hepatic galactose concentrations to be one-half of circulating media levels. Glucose output was observed in each group during perfusion with either galactose or glucose. In the immature liver, galactose perfusion stimulated more glucose output than did the glucose perfusion. In the adult, however, both sugars resulted in the same levels of glucose output. Galactose perfusion resulted in glucose levels in young liver being higher than the media; while in the adult, the level was lower than the media. Galactose perfused livers of the suckling and adult contained significantly more uridine-5'-diphosphogalactose than the glucose perfused livers of each age.

Role of iron deposition in Sphaerotilus discophorus.

Various physiological aspects of the process of iron deposition in Sphaerotilus discophorus were examined to elucidate its role. The values of iron/protein ratios suggested that a direct relationship existed between the iron concentration of the media and the magnitude of final iron deposition. Saturation of the organism's iron deposition system occurred at a 2.0 mM iron concentration, at a value of 0.6 mg of ferric ion per mg of cell protein. Laboratory data indicated that the strain's very low capacity for iron deposition observed at low external iron concentrations makes it unlikely that it is significant in limiting iron in the natural milieu. Under optimal iron concentrations, however, strain SS1 caused precipitation of iron (adsorbed to cellular material) in broth cultures, which was 10 to 100 times that mediated by some "non-iron" microorganisms. The strain's iron requirement, which was found to be between 0.003 and 0.02 mM, is commensurate with that of other microbes. One hundred micrograms of Mn(II) per ml and possibly 10 mug of either Co(II) or Ni(II) per ml could inhibit iron uptake in the deposition system. Sphaerotilus, when tested for its ability to withstand toxic concentrations of certain trace elements (Co, Cu, Mn, Ni, and Cd), demonstrated no exceptional resistance with respect to several other common microorganisms. Final cell yields were not affected by a varying iron concentration for Sphaerotilus growing under conditions of limiting carbon and nitrogen.

Measurement of growth and iron deposition in Sphaerotilus discophorus.

Aspects of the physiology of iron deposition of an iron-precipitating strain of Sphaerotilus were investigated in laboratory culture to characterize the process. Measurement of growth (incorporated L-[3H]alanine) and iron deposition (incorporated 59Fe) demonstrated that Sphaerotilus exhibit a characteristic temporal pattern of iron deposition, which is delayed until the latter portion of the exponential or the onset of the stationary growth phase. The growth rate (mu=0.17 h-1) was apparently independent of the iron concentration in the medium. There was, furthermore, no direct correlation between the iron concentration and final cell protein yield. It was concluded from experiments involving growth on artificial substrata (glass cover slips) that sessile populations derived no phsiological advantage (manifested as differences in growth rates) over free-living cells. There was no difference in the rate or onset of iron deposition of attached compared to suspended cells. Blocking of protein synthesis by the addition of chloramphenicol suggested that, once iron deposition was initiated, continued protein synthesis was not required for full expression of this capability. The results suggested that iron deposition may be possibly mediated by certain of the constituents of the organism's sheath.