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Biomedical subjects

K L Jones

Publications and source records attributed to K L Jones.

At least 91 records · Page 5Linked to original sources
PubMed1998

Neuropsychological comparison of alcohol-exposed children with or without physical features of fetal alcohol syndrome.

Fetal alcohol syndrome (FAS) is associated with behavioral and cognitive deficits. However, the majority of children born to alcohol-abusing women do not meet the formal criteria for FAS and it is not known if the cognitive abilities of these children differ from those of children with FAS. Using a set of neuropsychological tests, 3 groups were compared: (a) children with FAS, (b) children without FAS who were born to alcohol-abusing women (the PEA group), and (c) normal controls. The results indicated that, relative to controls, both the FAS and the PEA groups were impaired on tests of language, verbal learning and memory, academic skills, fine-motor speed, and visual-motor integration. These data suggest that heavy prenatal alcohol exposure is related to a consistent pattern of neuropsychological deficits and the degree of these deficits may be independent of the presence of physical features associated with FAS.

Adolescent↗
PubMed1998

Rate of gastric emptying is a determinant of postprandial hypotension in non-insulin-dependent diabetes mellitus.

1. Postprandial hypotension is now recognized as an important clinical problem, particularly in the elderly and in patients with autonomic dysfunction. The mechanisms responsible are poorly understood; however, impaired regulation of splanchnic blood flow and the release of gastrointestinal hormones appear to be important. The effect of gastric emptying on the magnitude of the postprandial fall in blood pressure has not been evaluated. 2. The aim of this study was to determine whether there is a relationship between changes in blood pressure and the rate of gastric emptying after ingestion of 75 g of glucose in patients with non-insulin-dependent diabetes mellitus (NIDDM) and both young and older normal subjects. Sixteen patients with recently diagnosed NIDDM, median age 57 (39-79) years, 10 'young' subjects with a median age of 23 (19-26) years and nine 'older' subjects, median age 48 (40-68) years, were measured simultaneously for gastric emptying of 75 g of glucose in 350 ml of water blood pressure and blood glucose concentrations, commencing at approximately 10.00 hours after an overnight fast. Measurements of blood pressure were made in the sitting position immediately before glucose ingestion and at 15 min intervals up to 180 min. 3. Gastric emptying of glucose was not significantly different between the three groups [50% emptying time (T50): 95 +/- 7.3 min in patients with NIDDM compared with 120 +/- 13.2 min in the 'young' group and 97 +/- 8.1 min in the 'older' group]. There was a significant fall in mean blood pressure after the glucose load in the patients with NIDDM (P < 0.0001) and the 'older' normal subjects (P < 0.05), but not the 'young' normal subjects. Postprandial hypotension (fall in systolic blood pressure > or = 20 mmHg) was evident in seven (44%) patients with NIDDM and three (33%) 'older' normal subjects. The area under the change in mean blood pressure curve was related significantly to the gastric emptying T50 (r = 0.67, P < 0.005) in the patients with NIDDM, but not in either control group. 4. In conclusion, in patients with recently diagnosed NIDDM the fall in blood pressure after an oral glucose load is (i) greater than in both young and older normal subjects and (ii) related to the rate of gastric emptying.

Adult↗
PubMed1998

Effects of nitroglycerin on liquid gastric emptying and antropyloroduodenal motility.

The effects of the nitric oxide donor nitroglycerin on gastric emptying and antropyloroduodenal motility were evaluated in nine healthy male subjects (ages 19-36 yr). Antropyloroduodenal pressures were recorded with a manometric assembly that had nine side holes spanning the antrum and proximal duodenum and a pyloric sleeve sensor; gastric emptying was quantified scintigraphically. In each subject, the emptying of 300 ml of 25% glucose labeled with 99mTc was assessed on two separate days during intravenous infusion of either nitroglycerin (5 micrograms/min in 5% dextrose) or 5% dextrose (control). Studies were performed with the subject in the supine position; blood pressure and heart rate were monitored. Nitroglycerin had no significant effect on blood pressure or heart rate. Nitroglycerin slowed gastric emptying (P < 0.02), and this was associated with greater retention of the drink in the proximal stomach (P < 0.05). In both nitroglycerin and control studies, ingestion of the drink was associated with an increase in the number of isolated pyloric pressure waves (P < 0.05) and antral pressure wave sequences (P < 0.05). Nitroglycerin reduced the number of isolated pyloric pressure waves (P < 0.05), basal pyloric pressure (P < 0.05), and the number of antral pressure wave sequences (P < 0. 05), but not the total number of antral pressure waves. The rate of gastric emptying and the number of isolated pyloric pressure waves were inversely related during control (P = 0.03) and nitroglycerin (P < 0.05) infusions. We conclude that in normal subjects, 1) gastric emptying of 300 ml of 25% glucose is inversely related to the frequency of phasic pyloric pressure waves, and 2) nitroglycerin in a dose of 5 micrograms/min inhibits pyloric motility, alters the organization but not the number of antral pressure waves, and slows gastric emptying and intragastric distribution of 25% glucose.

Adult↗
PubMed1998

Superoxide released from neutrophils causes a reduction in nitric oxide gas.

Exhaled nitric oxide (NO) is increased in some inflammatory airway disorders but not in others such as cystic fibrosis and acute respiratory distress syndrome. NO can combine with superoxide (O-2) to form peroxynitrite, which can decompose into nitrate. Activated polymorphonuclear neutrophils (PMNs) releasing O-2 could account for a reduction in exhaled NO in disorders such as cystic fibrosis. To test this hypothesis in vitro, we stimulated confluent cultures of LA-4 cells, a murine lung epithelial cell line, to produce NO. Subsequently, human PMNs stimulated to produce O-2 were added to the LA-4 cells. A gradual increase in NO in the headspace above the cultures was observed and was markedly reduced by the addition of PMNs. An increase in nitrate in the culture supernatant fluids was measured, but no increase in nitrite was detected. Superoxide dismutase attenuated the PMN effect, and xanthine/xanthine oxidase reproduced the effect. No changes in epithelial cell inducible NO synthase protein or mRNA were observed. These data demonstrate that O-2 released from PMNs can decrease NO by conversion to nitrate and suggest a potential mechanism for modulation of NO levels in vivo.

Animals↗
PubMed1998

Effects of meal volume and posture on gastric emptying of solids and appetite.

The effects of volume and posture on gastric emptying and intragastric distribution of a solid meal and appetite were evaluated. Eight normal volunteers were studied on four occasions, on each of which a meal comprising ground beef mixed with tomato sauce of either 650 g ("large") or 217 g ("small") was eaten. Two studies were performed while the subject was lying in the left lateral decubitus position, and two studies were performed while the subject was sitting so that in each subject data were available for both meals and in both postures. Hunger and fullness were evaluated using a visual analog questionnaire. In both postures and after both meals, gastric emptying approximated a linear pattern after an initial lag phase. The lag phase was shorter for the large meal when compared with the small meal [sitting: large 13 +/- 5 vs. small 29 +/- 7 min; left lateral: large 16 +/- 3 vs. small 24 +/- 3 min, F(1, 7) = 46.3, P < 0.0005]. In both postures the contents of the total [F(1,7) = 1794.5, P < 0.0001], proximal [F(1,7) = 203.7, P < 0.0001], and distal [F(1,7) = 231.5, P < 0.0001] stomach were greater after the large meal when compared with the small meal. Although the 50% emptying time was greater with the large than the small meal [F(1,7) = 40.8, P < 0.001], the postlag emptying rate (g/min) was more rapid with the large meal [sitting: large 1.7 +/- 0.2 vs. small 1.1 +/- 0. 1 g/min; left lateral: large 1.8 +/- 0.1 vs. small 1.3 +/- 0.04 g/min, F(1,7) = 44.7, P < 0.0005]. There was a significant interaction between meal volume and posture for retention in the distal stomach [F(1,7) = 7.14, P < 0.05]. Contrasts were used to evaluate the effects of volume and posture between the four studies and demonstrated an effect of posture for the large [F(1,21) = 18.7, P < 0.005] but not the small [F(1,21) = 0.30, P = 0.60] meal so that the retention was greater in the sitting when compared with the left lateral position. The magnitude of the postprandial increase in fullness [F(1,7) = 7.8, P < 0.05] and reduction in hunger [F(1,7) = 5.9, P < 0.05] was greater with the large meal. We conclude that meal volume has a major effect on gastric emptying; in contrast posture has only a minor impact on intragastric meal distribution, which is observed only after a large meal, and no effect on gastric emptying.

Adolescent↗
PubMed1998

Non-insulin dependent diabetes in children and adolescents: the therapeutic challenge.

Data are presented comparing non-insulin dependent diabetes mellitus (NIDDM) and insulin dependent diabetes mellitus (IDDM) in youth. Children and adolescents with NIDDM were predominantly Mexican-American, presented less frequently in ketoacidosis, had a greater frequency of family history of diabetes, had higher BMIs (27.4 vs 16.6 kg/m2), and had higher frequency of acanthosis nigricans (67% vs 1.2%). Logistical, social, and cultural challenges facing the physician treating children and adolescents with NIDDM are discussed, and treatment options for NIDDM in youth are briefly reviewed.

Acanthosis Nigricans↗
PubMed1998

Acid-base homeostasis in children with growth hormone deficiency.

BACKGROUND: Although the primary use of growth hormone (GH) is to promote linear growth, it is also known to affect many metabolic processes and to influence renal function. In laboratory animals, growth hormone deficiency (GHD) causes a mild metabolic acidosis that is corrected by GH treatment. We observed a patient with GHD who initially presented with acidosis of unclear etiology and corrected the acidosis with GH treatment. OBJECTIVES: To determine: 1) whether children with GHD have lower mean serum bicarbonate concentrations than do children with short stature because of other causes; and 2) whether the presence of a low serum bicarbonate concentration increases the probability of GHD among children with short stature. METHODS: We collected data from the medical records of 143 children with short stature who had serum electrolyte concentrations measured as part of their initial evaluations, 66 with GHD and 77 with short stature as a result of other causes. We compared mean serum bicarbonate concentrations and bicarbonate standard deviation scores (SDS) between these two groups and determined the probability of GHD for patients according to bicarbonate SDS. RESULTS: The mean serum bicarbonate concentration was significantly lower in patients with GHD (mean standard deviation [SD]; 23.9 [0.4] mEq/L vs 25.2 [0.3] mEq/L) as was the bicarbonate SDS (-0.12 [0.14] SD vs 0.38 [0.10] SD). Twelve (75%) of 16 patients with bicarbonate SDS </=-1 SD had GHD compared with 7 (28%) of 25 patients with bicarbonate SDS >1 SD. Patients with bicarbonate SDS between -1 SD and 1 SD had an intermediate probability of GHD, 46/102 (45%), similar to the overall prevalence of GHD in the study population (46%). Mean bicarbonate concentrations and bicarbonate SDS increased significantly in 9 patients who had repeat electrolyte measurements during treatment with GH (mean bicarbonate; 21.7 [1.1] mEq/L vs 26.9 [0.59] mEq/L, mean bicarbonate SDS; -1.24 [0.43] SD vs 0.55 [0.27] SD). CONCLUSIONS: Serum bicarbonate concentrations are lower in patients with GHD than in patients with short stature as a result of other causes. In addition, serum bicarbonate concentrations rise with GH treatment in patients with GHD. The probability of GHD is increased for patients with bicarbonate SDS </=-1 SD and decreased for patients with bicarbonate SDS >1 SD. These findings indicate a role for GH in maintaining normal acid-base homeostasis and suggest that GHD should be considered in children whose growth failure is attributed to other causes of acidosis.

Acid-Base Equilibrium↗
PubMed1998

Non-insulin dependent diabetes mellitus in Mexican-American children.

To define the clinical and metabolic characteristics of children with non-insulin-dependent diabetes mellitus (NIDDM), we reviewed the medical records of 18 children and adolescents who met either or both of the following criteria for the diagnosis of the disease: evidence of continued endogenous secretion of insulin beyond that expected in insulin-dependent diabetes mellitus and satisfactory glycemic control with diet alone or in combination with an oral hypoglycemic agent more than 2 years from the time of diagnosis. Patients who met these criteria but had islet cell antibodies or insulin autoantibodies were eliminated from the study group. Patients with NIDDM constituted 8% of all patients with diabetes seen in our pediatric clinics and 19% of diabetic patients of Central or South American ancestry. Of the 18 patients, 12 (67%) were Mexican American. The mean age of onset was 12.8 years (range, 5 to 17). Obesity (n = 9) and acanthosis nigricans (n = 12) were common findings. Ketonuria was present at diagnosis in 5 (33%) of 15 patients and acidosis in 2 of 14 (14%). Challenge with a nutritional supplement (Sustacal, Mead Johnson Nutritionals) (n = 10) showed a mean fasting serum C-peptide concentration of 1.19 nmol per liter (3.6 ng per ml). A family history of NIDDM was present in 13 (87%) of 15 patients, with 7 (47%) having 3 or more generations affected. Children with NIDDM are an important subset of those with diabetes, and this disease should be suspected in diabetic children presenting without ketoacidosis and with acanthosis nigricans, obesity, and a strong family history, particularly among those of Mexican-American ethnicity. Children with these characteristics should undergo testing of endogenous insulin secretion for appropriate therapeutic intervention.

Adolescent↗
PubMed1997

Prader-Willi and Angelman syndromes: diagnosis with a bisulfite-treated methylation-specific PCR method.

The putative promoter region of the SNRPN gene contains a CpG island which is heavily methylated in the maternally derived allele and unmethylated in the paternally derived allele. In patients with Prader-Willi syndrome (PWS) only the methylated allele is present, while in those with Angelman syndrome (AS) only the unmethylated allele is present. The purpose of this paper is to report a polymerase chain reaction (PCR)-based assay to evaluate methylation status of the CpG island of the SNRPN gene and to show that this assay allows rapid diagnosis of PWS and AS. Methylated cytosines in the CpG dinucleotide are resistant to chemical modification by sodium bisulfite. In contrast, bisulfite treatment converts all unmethylated cytosines to uracil. Based on this differential effect, the bisulfite-modified DNA sequence of a methylated allele was successfully distinguished from that of an unmethylated allele using 2 sets of allele-specific primer pairs: a methylated allele-specific primer pair (MET) and an unmethylated allele-specific primer pair (UNMET). Bisulfite-modified DNA from 10 patients with PWS amplified only with the MET pair while modified DNA from 5 patients with AS amplified only with the UNMET pair. Modified DNA from 50 normal unrelated individuals amplified with both primer pairs. In that methylation-specific PCR (MSPCR) can detect all presently testable causes of PWS and AS in a rapid and cost-effective fashion, serious consideration should be given to the use of this test in the initial evaluation of all patients in which PWS or AS is being considered.

Angelman Syndrome↗
PubMed1997

Spatial patterns of fasting and fed antropyloric pressure waves in humans.

1. Gastric mechanics were investigated by categorizing the temporal and spatial patterning of pressure waves associated with individual gastric contractions. 2. In twelve healthy volunteers, intraluminal pressures were monitored from nine side hole recording points spaced at 1.5 cm intervals along the antrum, pylorus and duodenum. 3. Pressure wave sequences that occurred during phase II fasting contractions (n = 221) and after food (n = 778) were evaluated. 4. The most common pattern of pressure wave onset along the antrum was a variable combination of antegrade, synchronous and retrograde propagation between side hole pairs. This variable pattern accounted for 42% of sequences after food, and 34% during fasting (P < 0.05). Other common pressure wave sequence patterns were: purely antegrade-29% after food and 42% during fasting (P < 0.05); purely synchronous-23% fed and 17% fasting; and purely retrograde-6% fed and 8% fasting. The length of sequences was shorter after food (P < 0.05). Some sequences 'skipped' individual recording points. 5. The spatial patterning of gastric pressure wave sequences is diverse, and may explain the differing mechanical outcomes among individual gastric contractions. 6. Better understanding of gastric mechanics may be gained from temporally precise correlations of luminal flows and pressures and gastric wall motion during individual gastric contraction sequences.

Adult↗
PubMed1997

Ritscher-Schinzel (3C) syndrome: documentation of the phenotype.

Ritscher-Schinzel syndrome or 3C (craniocerebello-cardiac) syndrome is characterized by cardiac defects, cerebellar vermis hypoplasia, and cranial defects. Nineteen cases were reported previously; however, the full spectrum of this disorder has not been determined. We have evaluated two unrelated males with this condition. Both had defects of the endocardial cushion and vermis hypoplasia with hypotonia. In addition, both had hypospadias, a previously undescribed finding of this disorders. Review of the previously reported cases and those described herein demonstrate: 1) Although varying degrees of vermis hypoplasia are accompanied by hypotonia, delayed gross motor function improves with advancing age leaving speech delay as the major neurodevelopmental handicap. 2) Two different types of cardiac anomalies occur: defects of the endocardial cushion ranging from anomalies of the mitral or tricuspid valves to complete AV canal, and/or conotruncal defects. 3) Postnatal growth deficiency was seen in most patients in whom longitudinal information was available. In our review of patients with vermis hypoplasia we ascertained a patient diagnosed as having "Joubert syndrome" who had most findings of the Ritscher-Schinzel syndrome and several other patients with "Dandy-Walker syndrome" who likely have had Ritscher-Schinzel syndrome, suggesting that Ritscher-Schinzel syndrome is more common than has been appreciated. Careful search for the subtle facial changes characteristic of this disorder as well as coloboma, cleft palate/bifid uvula, short neck, syndactyly, and hypoplasia of the nails is warranted when evaluating children with Dandy-Walker malformation with or without clinical signs of Joubert syndrome.

Abnormalities, Multiple↗
PubMed1997

Heavy prenatal alcohol exposure with or without physical features of fetal alcohol syndrome leads to IQ deficits.

OBJECTIVE: To assess general intellectual functioning in children with histories of heavy prenatal alcohol exposure, with or without the facial features and growth deficiencies characteristic of fetal alcohol syndrome (FAS). DESIGN: Forty-seven alcohol-exposed children were recruited on evaluation at a dysmorphology clinic and evaluated as part of a university research project using standard tests of IQ. Thirty-four of the alcohol-exposed patients met the traditional diagnostic criteria for FAS. The other 13 alcohol-exposed children lacked both the pattern of facial features and prenatal or postnatal growth deficiency characteristic of the diagnosis. RESULTS: Compared with normal control subjects matched for age, sex, and ethnicity, both groups of alcohol-exposed children displayed significant deficits in overall IQ measures and deficits on most of the subtest scores. Although those in the nondysmorphic group usually obtained marginally higher IQ scores than those in the FAS group, few significant differences were found between the two alcohol-exposed groups. CONCLUSIONS: These results indicate that high levels of prenatal alcohol exposure are related to an increased risk for deficits in intellectual functioning and that these can occur in children without all of the physical features required for a diagnosis of FAS. They also emphasize the need for conducting a thorough history of prenatal alcohol exposure in children with intellectual deficits.

Child↗
PubMed1997

Relation between postprandial satiation and antral area in normal subjects.

The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

Adult↗
PubMed1997

The effect of cisapride on oral and intravenous glucose tolerance in normal subjects.

Cisapride is used widely for the treatment of diabetic gastroparesis. There is some evidence that cisapride may influence insulin secretion. The aim of this study was to evaluate the effect of cisapride on plasma concentrations of glucose, insulin and C-peptide in response to oral and intravenous glucose loads. Twelve normal subjects took cisapride and placebo, each for 10 days using a randomized, double-blind, crossover design. In each treatment phase, the plasma glucose, insulin and C-peptide response to intravenous (0.5 g/kg) and oral (75 g) glucose loads was evaluated on separate days. Gastric emptying of the oral glucose load was also measured. After the intravenous glucose load, plasma concentrations of C-peptide were higher (P< 0.01) on cisapride when compared with placebo (e.g. peak C-peptide 2.08+/-0.25 nmol/L vs 1.78+/-0.22 nmol/L, P< 0.01) while there was no significant difference in plasma glucose or insulin. Cisapride had no effect on the rate of gastric emptying of the oral glucose load. Mean plasma concentrations of insulin and C-peptide were higher after oral glucose on cisapride than placebo, but these differences were not significantly different. These observations indicate that cisapride may increase glucose-stimulated insulin secretion.

Administration, Oral↗
PubMed1997

Effects of small intestinal nutrient infusion on appetite and pyloric motility are modified by age.

The mechanisms responsible for the reduction in appetite and slowing of gastric emptying in older persons are unknown. The aims of this study were to evaluate the effects of aging on small intestinal regulation of appetite and pyloric motility. Eight healthy older (age 65-75 yr) and seven healthy young (age 20-34 yr) male subjects received isocaloric (2.9 kcal/min) intraduodenal infusions of lipid and glucose for 120 min, each on separate days. During the intraduodenal infusions, perceptions of hunger, desire to eat, and fullness were assessed by visual analog scales. Pyloric motility (isolated pyloric pressure waves and tonic pyloric pressure) was measured by manometry during the intraduodenal lipid infusion. On each day, after completion of the intraduodenal nutrient infusion the subject was offered a buffet meal and food intake was quantified. Before intraduodenal nutrient infusions, sensations of hunger (P < 0.01) and desire to eat (P < 0.05) were less in the older compared with the young subjects. In the young, intraduodenal lipid suppressed hunger to a greater extent than intraduodenal glucose (P < 0.05). In older persons, neither intraduodenal nutrient infusion suppressed hunger. Intraduodenal lipid and glucose increased fullness in both age groups (P < 0.05 for both), with no significant difference between the two nutrients. There was no significant difference in food intake from the buffet meal between the elderly and young subjects. Intraduodenal lipid infusion stimulated phasic pyloric pressure waves in both age groups (P < 0.01 for both), and this response was greater (P < 0.05) in older persons. There was an increase (P < 0.01) in tonic pyloric pressure during intraduodenal lipid infusion that was not significantly different between the two age groups. We conclude that the effect of small intestinal lipid infusion on hunger is attenuated, and the stimulation of phasic pyloric pressure waves increased in healthy older persons compared with healthy young males. Increased feedback from small intestinal nutrients does not appear to be responsible for the physiological anorexia of aging.

Adult↗
PubMed1997

Parametric imaging of the chick embryonic cardiovascular system: a novel functional measure.

Morphogenesis of the cardiovascular system is likely linked to its functional development. This report presents an approach to functional assessment of early cardiovascular development using parametric imaging based on videodensitometry. Trypan blue was injected into the sinus venosus of chick embryos at stage 20 (3.5 d of incubation). Images were recorded on videotape, digitized, and analyzed by a microcomputer. A sampling window was placed over the entire image, and a densogram (time-density curve) for each pixel in the window was obtained. Parameters extracted from the densogram and its derivative were plotted in form of: 1) maximal image, 2) peak derivative image, and 3) time to peak derivative image. This approach revealed isochronal lines that divide the aortic arch and dorsal aorta into several segments. Regional flow velocity at these segments was estimated by dividing the distance between isochronal lines by the time interval. Flow velocity at the mid-systolic phase at the dorsal aorta and at the fourth aortic arch was 35.9 and 45.0 mm/s, respectively. Shear rate at the vessel wall was estimated to be 2.7 times larger at the fourth aortic arch than at the dorsal aorta. The extensive remodeling experienced by the aortic arch system compared with the dorsal aorta could be related to increased shear rate on the walls of the aortic arches.

Animals↗
PubMed1997

Comparison of bone density measurement techniques: DXA and Archimedes' principle.

The standard method for determination of density (g/cm3) of bones from small animals has been the application of Archimedes' principle. A recent development has been software for the determination of "density" (g/cm2) of small animal bones with dual-energy X-ray absorptiometry (DXA). We compared Archimedes' principle and DXA (Hologic QDR-2000) in the measurement of the densities of whole and hollowed femurs of 5- to 6-month-old retired female breeder rats. In an attempt to ensure detectable treatment differences, rats were used from a low-vitamin D Holtzman and a supplemental-vitamin D Sprague-Dawley colony. Whole femur densities were higher for supplemental-vitamin D colony rats than for low vitamin D rats using both techniques (Archimedes' principle, p < 0.002; DXA, p < 0.005), and the densities from the two techniques were highly correlated (r = 0.82, p < 0.0001). Actual density values were higher for Archimedes' principle than for DXA. Other variables such as femur ash weight and calcium content were also highly correlated to densities with both techniques. Hollowed femur density values were higher than whole femur values with Archimedes' principle but lower with DXA. Colony effects for hollowed femur densities were diminished with Archimedes' principle (p < 0.03) and eliminated with DXA (p < 0.53). Investigation of whole bones is more biologically relevant, and both techniques were effective in detecting differences between whole femurs from low-vitamin D and supplemental-vitamin D colony rats.

Absorptiometry, Photon↗