Visceral fat and cardiovascular risk factors in Chinese NIDDM patients

OBJECTIVE

The interrelations between obesity, glucose intolerance, hypertension, dyslipidemia, and insulin resistance are well recognized. These relationships are of particular interest in Hong Kong's Chinese population, in whom increasing affluence has coincided with a marked increase in the prevalence of NIDDM. We designed a pilot study to examine the relationships between visceral fat and cardiovascular risk factors in Chinese NIDDM patients.

RESEARCH DESIGN AND METHODS

We studied 21 Chinese NIDDM patients whose visceral fat was quantified by magnetic resonance imaging. Cardiovascular risk factors including plasma lipids and 24-h ambulatory blood pressure (BP) were measured. In addition, insulin resistance was determined by a short insulin tolerance test (SITT).

RESULTS

Increased visceral adiposity was significantly correlated with plasma triglycerides (r = 0.63, P = 0.004), the total cholesterol/HDL cholesterol ratio (r = 0.61, P = 0.008), the urinary albumin/creatinine ratio (r = 0.49, P = 0.04), and decreased insulin sensitivity as measured by the SITT (r = 0.47, P = 0.03). When the data were analyzed by tertiles, increasing visceral fat area was associated with higher plasma triglycerides, lower HDL cholesterol, and a smaller plasma glucose decrement during the SITT. In addition, the diurnal rhythm in BP and heart rate tended to be best preserved in those with the least visceral obesity.

CONCLUSIONS

This pilot study demonstrates that visceral fat accumulation is associated with dyslipidemia, hypertension, insulin resistance, and albuminuria in Chinese patients with NIDDM.

Dosimetry of pediatric radiopharmaceuticals: uniformity of effective dose and a simple aid for its estimation

Formulae were investigated for predicting the effective dose to children, per unit administered activity of various pediatric radiopharmaceuticals, based only on the weight of the patient. Their influence on the uniformity of effective dose from total administered activity was also examined.

METHODS

The formulae were obtained from calculations of effective dose per unit administered activity (mSv x MBq[-1]) for five anthropomorphic mathematical phantoms applicable for newborn, 1-yr-, 5-yr-, 10-yr- and 15-yr-old children, having body weights of 3.4, 9.8, 19, 32 and 57 kg, respectively, using published biokinetic models.

RESULTS

In general, there was good linear correlation between effective dose per unit administered activity and inverse weight but, for some radiopharmaceuticals, logarithmic regression on weight provided a better fit to the data. An administered activity schedule based on body surface area, used with these formulae, resulted in reasonable uniformity of effective dose for children of all ages, with varying degrees of uniformity for different radiopharmaceuticals (coefficient of variation (COV) up to 20%). Individual activity schedules for separate radiopharmaceuticals gave best uniformity (COV < 7%) while a single general schedule, based on the mean results of the present study, yielded acceptable uniformity (COV < or = 10%) over the pediatric range.

CONCLUSION

Effective dose per unit administered activity (mSv x MBq[-1]) of pediatric radiopharmaceuticals can be predicted from body weight alone by using simple formulae, and appropriately choosing the administered activity schedule leads to similar values of effective dose for children of all ages from a given radiopharmaceutical procedure.

Development of a radiopharmaceutical activity schedule for technetium-99m dimercaptosuccinic acid in children based on image quality criteria

The aim of this study was to determine an activity schedule (amount of administered activity in relation to body weight) for technetium-99m dimercaptosuccinic acid examinations in children, from information present in renal scintigraphic images. Scans from 48 children (5 weeks to 14.8 years old) were graded for image quality according to the clarity of both kidney outline and internal structure. Numerical image data (kidney and background counts, signal-to-noise ratio) were associated with these subjective gradings to formulate three criteria, specifying the required values of the above-measured parameters to yield optimum grades of image quality. When applied to derived functions, a kidney uptake of 20% was required to satisfy the criterion based on the signal-to-noise ratio. Using this value with the other two criteria predicts the form of the weight-dependent activity schedule as a function of imaging time. Examples of schedules for imaging times of 300 and 600 s are compared with a schedule based on surface area.

Functional identification of calcium binding residues in bovine alpha-lactalbumin

The functional role of previously identified calcium binding residues in alpha-lactalbumin (alpha-LA) was investigated by site-directed mutagenesis. Mutation of D82 to alanine did not effect the binding affinity for calcium, the protein structure, or its function in the lactose synthase assay, suggesting that this aspartate side chain is not essential for calcium binding or structural stabilization. In contrast, mutation of either D87 or D88 to alanine completely eliminated the strong calcium binding and altered alpha-LA as shown by several spectroscopically derived properties such as near- and far-UV CD and intrinsic fluorescence studies. These latter two mutants displayed significantly reduced abilities to stimulate lactose synthase activity (<3.5% of the maximal rate). Additionally, residues K79 and D84, which chelate calcium by backbone carbonyls, were mutated to alanine. K79A lost approximately 50% of its tertiary structure and stability (as determined by CD) but retained full calcium binding activity, indicating that at least the lysine side chain does not influence the carbonyl-mediated calcium coordination. In contrast, D84A lost approximately 25% of its tertiary structure and stability which was accompanied by a modest reduction in calcium affinity. Both mutants were able to stimulate normal lactose synthase activity. The triple mutant, D82A/D87A/D88A alpha-LA, lost its ability to bind calcium, similar to D87A and D88A. These studies clearly demonstrate the importance and variation of side chain interactions, which might be the seminal event in the establishment of the correct calcium binding loop conformation, possibly to stabilization and final folding of the overall protein structure.

Assessment of drainage in PUJ dilatation: pelvic excretion efficiency as an index of renal function

Renal function is important when assessing the response of a dilated renal pelvis to a diuretic stimulus. Yet there is little in the literature to suggest how this should be undertaken. Our aim was to develop a model which we have called pelvic excretion efficiency (PEE). The PEE, which may be used to assess drainage, is a mathematical model of the ratio of the total kidney excretion to the total amount of isotope extracted from the blood by the kidney. Thirty-three children with a prenatal diagnosis of unilateral renal pelvic dilatation (PUJ) were treated conservatively after birth. As a group, they underwent a total of 164 diuretic DTPA renograms up to the age of 72 months. Drainage was assessed as the response to frusemide (defined as the time for the corrected renal curve to fall to 75% of the maximum value in the frusemide part of the study; T75), response to bladder emptying, a change of posture after frusemide (PM), and PEE. The contralateral normal kidney showed a combination of both 'good' T75 and PM drainage in 51% of renograms while the PEE showed drainage in all. The affected kidney with renal pelvic dilatation showed a combination of both 'poor' T75 and PM drainage in 42% of renograms. The PEE was low in 99% of these 'poor drainage' renograms. The PEE, the ratio of the mathematical model of renal uptake to excretion, is readily calculated and may be a more accurate and specific technique to assess drainage on diuretic renography.

[Effects of beta-adrenergic agonists and phosphodiesterase inhibitors on the outflow facility of the eye]

Changes in the outflow facility of perfused bovine eyes and in the shape of cells in cultured trabecular meshwork (TM) were studied after exposure to adrenergic drugs. Dobutamine, a selective beta 1 agonist caused confluent TM cells to change from their usual polygonal shape to a characteristic stellate shape. Salbutamol, a selective beta 2 agonist showed no effect. The phosphodiesterase (PDE) inhibitors, isobutylmethylxanthine (IBMX), theophylline, and caffeine were also very effective in producing this shape change. Epinephrine, isoproterenol, dobutamine or salbutamol did not increase the outflow facility, at temperatures of 22 degrees C or 36 degrees C, whereas theophylline, caffeine and IBMX increased the facility in a dose-dependent manner. The high concentrations of beta-adrenergic agents required to produce even a small change in outflow facility and the cell shape argue against the involvement of adrenergic receptor mediation; on the other hand, the enhancement of the effects of epinephrine by PDE inhibitors and a similar effect produced by cAMP suggest that the changes in the cell shape are produced by beta-receptor activation. The beta-adrenergic agents were ineffective on changing outflow facility but the PDE inhibitors were remarkably effective in producing both shape change and increasing facility. PDE inhibition has much greater influence on and around the outflow channels than pure beta-adrenergic agonists, at least in enucleated bovine eyes.

Osteomyelitis occurring in the zygomatic bone

Osteomyelitis of bones in the middle third of the face is rare, especially in westernized populations. The actiology is usually due to odontogenic sources or infected fracture sites. An unusual case of osteomyelitis of the zygomatic bone resulting from the use of radiotherapy in the management of recurrent basal cell carcinoma is presented. This illustrates a late complication of therapy for a cancer which commonly occurs in the head and neck region and is rapidly increasing in incidence in the UK.

Non-invasive continuous arterial pressure, heart rate and stroke volume measurements during graded head-up tilt in normal man

The haemodynamic effects of head-up tilt (HUT) at different tilt angles were investigated non-invasively in eight normal male subjects. Mean arterial pressure (MAP; by Ohmeda Finapres 2300), stroke volume (SV) and heart rate (HR; by BoMed NCCOM3-R7S) were continuously recorded whilst performing a series of HUTs (55 degrees, 10 degrees, 20 degrees, 30 degrees and 55 degrees) lasting 3 min each. The response to HUT was proportional to the sinc of the tilt angle. The magnitude of the response varied between subjects. HUT to 55 degrees resulted in mean (95% confidence limits) increases in MAP by 16 (+/-16)% and HR by 11 (+/-24)% and a decrease in SV by -25 (+/-22)%. These results were repeatable after 30 min. At small tilt angles, i.e. < or = 20 degrees, MAP did not change and HR decreased by -3 (+/-4)%. A detailed analysis revealed immediate dynamic (0-30 s), late dynamic (30-90 s) and plateau (after 90 s) phases in the response to HUT. In conclusion, HUT produces reproducible haemodynamic effects, although differences exist among subjects. A detailed analysis of these effects can be successfully performed using non-invasive methods.

The cervical spine in Crouzon syndrome

STUDY DESIGN

All cervical spine radiographs of 44 patients with Crouzon syndrome treated at Great Ormond Street Hospital during the past 10 years were studied.

OBJECTIVES

To assess the incidence and pattern of cervical spine abnormalities of patients with a confirmed diagnosis of Crouzon syndrome, but particularly regarding progressive fusion.

SUMMARY OF BACKGROUND DATA

Previous studies into the cervical spine anomalies in those with Crouzon syndrome have shown an increased incidence of congenital abnormalities compared with the normal population. There is some suggestion from previous studies that cervical spine fusions are progressive in nature.

METHODS

All radiographs were reviewed by the craniofacial team, along with a single pediatric radiologist with experience in assessment of skeletal dysplasias.

RESULTS

Radiologic abnormalities included "butterfly" vertebrae and fusions of the bodies and the posterior elements. Evidence of fusion was present in eight of 44 (18%) of patients. C2-C3 and C5-C6 were almost equally affected. Block fusions involving multiple vertebrae were seen. Analysis of sequential studies in 16 patients showed evidence of progression in five.

CONCLUSIONS

These results reveal an incidence of fusions that is lower than reported previously. There is radiologic evidence from serial studies that the fusions are progressive, and because these patients are children, the fusion process may not be complete, which may account for the lower incidence of fusions than in previous studies. The pattern of fusions is different from that in earlier studies, which may be a result of the method of diagnosis because this population is less likely to include atypical forms of other syndromes (which have a higher incidence of cervical fusions, particularly at C2-C3). Regarding other congenital anomalies, it appears that butterfly vertebrae are especially prevalent in association with Crouzon syndrome.

Anomalous venous drainage in a case of non-syndromic craniosynostosis

The authors describe the clinical and radiological findings in a case of non-syndromic craniosynostosis affecting multiple sutures, in which the intracranial venous drainage was grossly anomalous. Investigation by magnetic resonance imaging and angiography revealed that almost all of the intracranial venous blood was draining from the dural sinuses transosseoussly via enlarged emissary veins to the external jugular veins and the vertebral veins. Although present, both internal jugular veins were small. This discovery represented a contraindication for the vault expansion surgery that had been recommended as treatment for the patient's raised intracranial pressure, and it has important implications for the management of all types of craniosynostosis.

Hand anomalies in Crouzon syndrome

OBJECTIVE

To review the hand radiographs of patients with Crouzon syndrome, to look for extracranial manifestations of the condition at this site.

DESIGN

The hand radiographs of those with Crouzon syndrome attending the Craniofacial Service at Great Ormond Street between 1985 and 1996 were reviewed.

RESULTS

Thirty-three patients underwent a total of 34 radiographs, one patient having had a serial study. This revealed a range of minor anomalies. Most striking was the presence of carpal fusions in four cases, a feature which has not previously been reported.

CONCLUSION

The hands of Crouzon syndrome may have anomalies including carpal fusions, and these results are evidence that the condition may produce subtle effects on the hands.

The feet in Crouzon syndrome

Eighteen patients with Crouzon syndrome were evaluated for anomalies of the feet. Clinical examination was unremarkable in all cases. Radiographs were evaluated by a radiologist with an interest in skeletal dysplasia, along with the craniofacial team. A range of radiographic anomalies was seen, with the phalanges, metacarpals, and tarsals all displaying anomalies. Only three cases had radiographically normal feet. These findings suggest that the effects on the feet, which, although subtle and not well described in the literature, are notable. Feet anomalies also occur with the other complex craniosynostosis syndromes resulting from mutations of fibroblastic growth factor receptor 2 molecule, such as those of Apert, Pfeiffer, and Jackson-Weiss syndromes.

Effects of adrenergic agents and phosphodiesterase inhibitors on outflow facility and cell shape of bovine trabecular meshwork

Changes in the outflow facility of perfused calf eyes and in the shape of cells in cultured trabecular meshwork (TM) have been studied, following exposure to adrenergic agents and phosphodiesterase inhibitors (PDE). Dobutamine caused confluent TM cells to change their usual polygonal shape to a characteristic stellate shape. Salbutamol had no effect, but PDE inhibitors, isobutylmethylxanthine (IBMX), theophylline, and caffeine were very effective in producing this shape change. Epinephrine, isoproterenol, dobutamine, and salbutamol did not increase the outflow facility, either at 22 degrees C or 36 degrees C, while theophylline, caffeine, and IBMX did increase it in a dose-dependent manner. On the other hand, the high concentrations of beta-adrenergic agents required to produce even a small change in outflow facility and cell shape argue against the involvement of adrenergic-receptor mediation and may suggest another mechanism; on the other, the enhancement of epinephrine effects by PDE inhibitors and the similar effect produced by cyclic adenosine 3',5'-cyclic phosphate (cAMP) and purines suggest that changes in the cell shape are produced by beta-receptor activation. The beta-adrenergic agents were not effective in changing outflow facility, but the PDE inhibitors were remarkably effective both in changing the shape and in increasing facility.

Single-dose pharmacokinetics of paracetamol and its conjugates in Chinese non-insulin-dependent diabetic patients with renal impairment

OBJECTIVE

A single oral dose of paracetamol (20 mg.kg-1) was given to 38 Chinese patients with non-insulin-dependent diabetes mellitus (NIDDM) who had either normal renal function or varying degrees of renal impairment, with creatinine clearances ranging from 4 to 123 ml.min-1.1.73 m-2. The plasma and urinary concentrations of paracetamol and its major metabolites were measured by high-performance liquid chromatography (HPLC).

RESULTS

The absorption and elimination of paracetamol were unaffected by renal impairment. However, the area under the plasma concentration time curve and the elimination half-life of paracetamol metabolites increased significantly with worsening renal insufficiency. Mean renal clearances of paracetamol and its conjugates were significantly reduced in these subjects. There was no evidence of altered metabolic activation with renal impairment.

CONCLUSION

The results demonstrate that paracetamol disposition is minimally affected by diabetic nephropathy; however, extensive accumulation of conjugates may occur.

The cervical spine in Saethre-Chotzen syndrome

Twenty patients with a diagnosis of Saethre-Chotzen syndrome had their cervical spine radiographs reviewed. Radiologic abnormalities including vertebral fusion were present in 9 of the 20 patients. Fusion of both the vertebral bodies and the posterior elements was noted, although the latter site was more common. C2-3 was the level most commonly involved, although other levels were recorded. Analysis of sequential radiographs in nine patients revealed evidence of progression in seven patients. In those studies in children aged under 2 years, only 1 of 18 films showed evidence of fusion, while in those over 2 years of age, 10 of 12 showed evidence of fusion. These results reveal that the incidence of cervical anomalies in Saethre-Chotzen syndrome is greater than that in the general population. There is both direct and indirect evidence that the vertebral fusions are progressive during childhood.

The hands in Saethre-Chotzen syndrome

The hand radiographs of fifteen patients with a diagnosis of Saethre-Chotzen syndrome were reviewed by a radiologist with an interest in skeletal dysplasia along with the craniofacial team. Eleven patients exhibited a range of bone abnormalities of the following sites: thumbs, fingers, metacarpals, and the radius. The epiphysis of the distal phalanx of the thumb was most commonly involved site with 7 of the 15 patients affected. In addition to the structural abnormalities all cases before puberty (14 out of 15 patients in this series) showed variable delay of the bone age.

Finger duplication in Apert's syndrome

Three cases of unilateral duplication of the little finger in children with Apert's syndrome are presented. They provide additional evidence that the hands in Apert's syndrome are not always symmetrically affected.

Dental findings in parents of children with cleft lip and palate

The incidence of dental abnormalities in the cleft lip and palate population has been reported to be much higher than in the normal population. The role of genes in the production of a cleft lip and palate, and dental anomalies is thought to be complex, with autosomal dominant, recessive, and x-linked genes all playing a role. Noncleft parents can carry some of the cleft lip and palate genes, which produce clinically subtle manifestations in their facial skeleton. The purpose of this study was to look for evidence of increased dental anomalies in the non-cleft parents of cleft lip and palate children. The dentitions of the parents of 60 children with different types of cleft lip and palate were examined prospectively to see whether or not they exhibited features found more readily in the cleft lip and palate rather than did the normal population. Their dentitions were studied to record the following dental features: congenitally missing teeth, supernumerary teeth, or morphologic changes of the crowns of the permanent teeth. The number and position of any frenal attachments were also recorded. The results of this study did not show any differences in incidence of dental anomalies from the noncleft population. There was no evidence to support the hypothesis that congenital absence of lateral incisors is a microform of cleft lip and palate. Further, these results also failed to reveal any consistent pattern in the number and position of frenal attachments.

Biokinetic behavior of technetium-99m-DMSA in children

After intravenous administration of 99mTc-DMSA, biokinetic data were collected from studies on 24 children aged from 5 wk to 14.8 yr (15 normal and 9 with renal pathology).

METHODS

Patients were imaged with a gamma camera up to 30 hr postinjection and the absolute activities in the kidneys, liver, spleen, bladder, knees and whole body were estimated using an attenuation-corrected conjugate counting technique. Renal uptake and elimination rates and urinary excretion of radioactivity were also measured.

RESULTS

In children with normal renal function, maximal kidney uptake was 42.4% +/- 5.4% and was taken up with a half-time of 1.0 +/- 0.2 hr. Renal excretion amounted to 18.0% +/- 4.4% at 24 hr and was lowest in children aged less than 1 yr. In children with abnormal renal function, apart from the expected reduction in renal uptake there was evidence of wider variations in uptake rate and increased urinary excretion. Mean uptakes in liver and spleen were approximately 5% and 2%, respectively, in all patients and uptake in knees, assumed to reside in the metaphyseal growth complexes, was 1.4%.

CONCLUSION

In children with normal renal function, there was little evidence of age-dependent biokinetic factors other than reduced urinary excretion and lower uptake in knees in children aged less than 1 yr. The results therefore suggest that a single biokinetic model may suffice for radiation dosimetry purposes in normal children irrespective of age.

Radiation dosimetry of technetium-99m-DMSA in children

Radiation dosimetry was performed on 24 children (aged 5 wk to 14.8 yr) who were undergoing routine diagnostic investigation of renal impairment with 99mTc-DMSA.

METHODS

Organ doses were calculated using MIRDOSE 3 with biokinetic data obtained in previously described studies, and effective doses and effective dose equivalents were estimated. Interpolation by inverse weight between pediatric anthropomorphic phantoms was compared with age-matching to discrete phantoms. Administered activities were scaled by body surface area from the adult activity of 100 MBq and the resulting radiation doses in normal children were compared with those that would have resulted from a schedule based on body weight.

RESULTS

The effective doses estimated by interpolation differed by up to 46% from those based on discrete phantoms and showed less variation. In children with normal bilateral renal function, the mean effective dose per administered activity was 0.91 +/- 0.08 mSv or 0.98 +/- 0.29 mSv by the two methods, respectively. Renal pathology reduced the effective dose, on average, by 15% of the value for normal patients.

CONCLUSION

Over the pediatric age range, the uniformity of effective dose values was improved by scaling the administered activity according to body surface area rather than to body weight.