Importance of growth hormone for the induction of hepatic low density lipoprotein receptors

This investigation was undertaken to determine the possible role of growth hormone (GH) in the hormonal regulation of hepatic low density lipoprotein (LDL) receptor expression. Treatment of normal rats with estrogen (ethynylestradiol, 5 mg/kg per day) increased the number of hepatic LDL receptors, and the LDL receptor mRNA levels were increased 2.4-fold. However, when hypophysectomized rats were treated with estrogen, the hepatic LDL receptor number and the mRNA levels only increased slightly. Treatment with GH was important to restore the induction of hepatic LDL receptors in hypophysectomized estrogen-treated rats. Further, the hypocholesterolemic effect of estrogen was abolished in hypophysectomized rats, and GH reversed this effect. To assess the effect of GH in humans, hepatic LDL receptor binding activity was determined in liver biopsy specimens from gallstone patients pretreated with GH (12 international units/day) prior to operation. GH administration induced hepatic LDL receptors approximately 2-fold, and this was accompanied by a 25% decrease in serum cholesterol. The LDL receptor stimulation caused by GH treatment was of similar magnitude as that observed upon 3 weeks of treatment with an established hypolipidemic drug (pravastatin or simvastatin). The data show that GH has an important role in the regulation of hepatic LDL receptors and suggest that GH secretion may be important for the control of plasma LDL levels in humans.

Hepatic cholesterol metabolism in estrogen-treated men

Operative liver biopsies were obtained from two male patients who developed gallstone disease during estrogen treatment of metastatic prostatic carcinoma. The heparin-sensitive binding of 125I-low-density lipoprotein (LDL) to liver homogenates (reflecting the expression of the LDL receptor) was determined, together with the activities of the rate-limiting enzymes in cholesterol synthesis [3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase], bile acid production (cholesterol 7 alpha-hydroxylase), and cholesterol esterification (acyl CoA:cholesterol acyl transferase). The results were related to data available in 18 patients (5 male, 13 female) who underwent cholecystectomy because of gallstone disease. The hepatic 125I-LDL-binding activity was increased threefold compared with five controls, and the activity of HMG-CoA reductase was increased twofold. There was no major difference in the activities of cholesterol 7 alpha-hydroxylase or acyl CoA:cholesterol acyl transferase. The concentration of free and total cholesterol in liver microsomes was approximately 30% lower in the estrogen-treated men than in 11 controls. The results indicate that estrogen at pharmacological doses stimulates hepatic LDL-receptor expression and HMG-CoA reductase activity in men. The increased LDL-receptor expression could in part explain the enhanced plasma clearance of injected 125I-LDL and hence the reduction in plasma LDL cholesterol previously shown to occur in estrogen-treated men.

Complications of cerebral angiography

All types of complications, both minor and major, are tabulated and analyzed in 5531 consecutive cerebral angiographies performed on 3730 patients during a period of 5 years.

Regulation of rat hepatic low density lipoprotein receptors. In vivo stimulation by growth hormone is not mediated by insulin-like growth factor I

Growth hormone (GH) has an important role in the regulation of hepatic LDL receptor expression and plasma lipoprotein levels. This investigation was undertaken to evaluate if these effects of GH on hepatic LDL receptors are direct or mediated by insulin-like growth factor I (IGF-I). Two models were studied in which substitution with GH is important for the regulation of hepatic LDL receptors: hypophysectomized rats receiving high-dose ethynylestradiol or challenge with dietary cholesterol. The hypophysectomized rats were hormonally substituted by infusion with dexamethasone and L-thyroxine, and either GH or IGF-I. In both models, GH was essential for maintaining normal expression of LDL receptors. In contrast, despite fully normalized plasma levels, IGF-I did not support the expression of hepatic LDL receptors. Analysis of plasma lipoproteins revealed that substitution with GH, but not with IGF-I, reduced LDL and intermediate density lipoproteins. In addition, determination of hepatic mRNA levels for apo B-100 and apo B-48 indicated that GH may be more effective than IGF-I in the promotion of apo B mRNA editing. In conclusion, GH has specific effects on hepatic LDL receptor expression and plasma lipoprotein levels that are not mediated by IGF-I.

Hormonal regulation of serum lipoprotein(a) levels. Contrasting effects of growth hormone and insulin-like growth factor-I

In response to treatment with growth hormone, serum levels of lipoprotein(a) increase, while those of LDL cholesterol decrease. To establish if increased levels of insulin-like growth factor-I may be of importance for these changes, we analyzed serum lipoprotein concentrations in 11 male patients with idiopathic osteoporosis who were treated with growth hormone (2 IU.m-2.d-1) or insulin-like growth factor-I (80 micrograms.kg-1.d-1) in a randomized, double-blind, cross-over study. LDL cholesterol was reduced by 0.7 mmol/L (P < .01) during growth hormone treatment but was not affected when the same patients received insulin-like growth factor-I. In contrast, mean lipoprotein(a) levels increased from 519 to 571 mg/L (P < .03) in response to growth hormone but were reduced from 538 to 478 mg/L (P < .04) during treatment with insulin-like growth factor-I. These results indicate that growth hormone exerts its effects on lipoprotein metabolism independent of insulin-like growth factor-I. Furthermore, the results suggest that treatment with insulin-like growth factor-I may reduce lipoprotein(a) levels.

The differential diagnosis of pontine angle meningioma and acoustic neuroma with computed tomography

Seven pontine angle meningiomas were examined with computed tomography (CT). The result was compared with that of a study of 61 acoustic neuromas. These two tumor types differ in manner of growth, volume, shape, attenuation, attachment to bone, cisternal deformation, frequency of calcification, peripheral edema, and bone changes.

Pigmented Nevi and Malignant Melanomas as Studied with a Specific Fluorescence Method

A specific fluorescence is developed in melanocytes, nevus cells, and cells of malignant melanoma by treatment of the tissue with dry formaldehyde gas. The fluorescence is often stronger in melanocytes adjacent to nevi or melanomas than in normal melanocytes. The strongest fluorescence occurs in cells of malignant melanoma. Among the limited number of compounds that condense with formaldehyde to fluorescent derivatives, DOPA [beta(3,4-dihydroxyphenyl)L-alanine] seems the most likely substance to give rise to the fluorescence observed in these lesions.

The hollow skull: a sign of brain death in Tc-99m HM-PAO brain scintigraphy

The advantage of Tc-99m HM-PAO, a newly introduced compound for brain perfusion imaging, is illustrated in three patients with suspicion of brain death. With Tc-99m HM-PAO, the carotid flow study is not essential, as it is in the Tc-99m pertechnetate carotid angiogram; planar images are equally useful; and there is no need for SPECT images. For the diagnosis of brain death, Tc-99m HM-PAO can be injected in the intensive care unit and planar images can be obtained at a later time using a mobile camera or whenever the patient can be moved to the nuclear medicine department.

GH is a regulator of IGF2 promoter-specific transcription in human liver

The regulation of the insulin-like growth factor-II gene (IGF2) is complex and involves the usage of four promoters resulting in different 5' untranslated regions, but with a common translated product. The IGF2 gene product is a mitogenic and survival factor that has been suggested to be important for a normal fetal development and cancer. In this paper we present evidence suggesting that the human IGF2 gene is regulated by GH, and that this regulation occurs in a promoter-specific way. Three lines of evidence support this finding. First, in vivo data from patients treated with GH (one injection or daily injections for 5 consecutive days) showed an increase in the IGF2 P2 promoter derived transcript after acute treatment, and of the P4 promoter transcript after short-term treatment while the P1 promoter derived transcript did not show any significant change. Secondly, isolated human liver cells treated with GH for 2 h displayed an upregulation of the P2 promoter derived transcript. Thirdly, employing transfection experiments in GH-receptor positive CHO cells with P2 and P4 promoter-luciferase constructs, an upregulation by GH was evident, while a P1 promoter construct was unresponsive. We suggest that GH may be a physiological regulator of IGF2 in humans.

Transient expression of insulin-like growth factor I immunoreactivity in skeletal muscle cells during postnatal development in the rat

The immunohistochemical expression of insulin-like growth factor I (IGF-I; somatomedin C) was investigated in hindlimb skeletal muscle of rats during postnatal development. IGF-I immunoreactivity could be demonstrated in satellite fibres and myotubes 1, 2 and 3 days after birth, while no IGF-I immunoreactivity could be demonstrated in the more mature primary fibres. Five days after birth only scattered cells showed IGF-I immunoreactivity and 10 days after birth no specific IGF-I immunoreactivity could be demonstrated in muscle cells, i.e. the adult pattern was established. It is concluded that IGF-I immunoreactivity is expressed during a limited period of postnatal skeletal muscle maturation in rats. IGF-I is probably synthesized by IGF-I immunoreactive muscle cells and contributes to the differentiation/maturation process by autocrine and/or paracrine mechanisms.

Diagnosis of acoustic neuroma with computed tomography

Sixty-one acoustic neuromas were examined with computed tomography (CT). For differential diagnosis the tumors were thoroughly analyzed for manner of growth, shape, volume, calcification, attenuation pattern, constrast enhancement, presence of peripheral edema, and cisternal deformation.

Progressive bilateral thinning of the parietal bones

Observation of a case of progressive bilateral parietal thinning within a period of 14 years induced us to study skull films of 3,636 consecutive patients. Parietal thinning was found in 86 patients (2.37%). It was more common in women, with a sex ratio of 1:1.9. The mean age of the females was 72 years, and that of the males 63 years. Previous skull films of 25 of these patients were available and showed progression in 10. It is concluded that parietal thinning is a slowly progressive disease of middle-aged and old patients and is not an anatomical variant or congenital dysplasia of the diploe.

Acetabular component migration in total HIP arthroplasty using CT and a semiautomated program for volume merging

Purpose: To develop a non-invasive method for detection of acetabular cup migration after total hip arthroplasty (THA) with a higher degree of accuracy than routine plain radiography.

Material and Methods: Two CT examinations, 10 min apart, were obtained from each of 10 patients that had undergone THA. Using an in-house developed semiautomated program for volume merging, the pelves in the two examinations were fused and the acetabular cup was visually and numerically evaluated to test the method's accuracy in detecting migration.

Results: In the visual evaluation of the best match a 1-mm translation of the cup was detectable. The numerical evaluation, comparing landmarks placed in the images of the acetabular cup and the head of the femur component in the two examinations, showed the mean difference in orientation of acetabular axes to be 2.5°, the mean distance between centre of cup face to be 2.5 mm and the mean distance between centre of the head of the prosthetic femoral component to be 1 mm.

Conclusion: This method has a significantly higher accuracy than routine plain radiography in detecting acetabular cup migration and could be used in clinical practice. It gives both a visual and a numerical correlate to migration.

Interaction between chlorpromazine and intrathecally injected non-ionic contrast media in non-anaesthetized rabbits

During a 14-day period, 45 of 78 rabbits were treated intravenously with chlorpromazine (5 mg kg-1 day-1). Metrizamide or iohexol was injected subarachnoidally and the neurotoxic effects of each substance on rabbit behaviour were evaluated for 3 h in both chlorpromazine-treated and non-treated rabbits. Chlorpromazine increased both the excitative and the depressive effects of metrizamide and the depressive effects of iohexol. No signs of excitation were observed in chlorpromazine-treated and non-treated rabbits after subarachnoid injections of iohexol. In spite of a free flow of clear fluid from the needle both before and after the intended subarachnoid injection, radiography disclosed that 26 of 67 suboccipital injections inadvertently resulted in a subdural deposition of the contrast medium. Contrast medium effects following subdural injection significantly differed from those following subarachnoid injection.

Long-term results after carotid artery surgery

This study presents the results from a follow-up after 414 carotid reconstructions performed on 352 patients during the years 1971-82. At the end of the follow-up period 267 patients were alive (75.8%) and 253 patients remained asymptomatic. The median follow-up time was 35 months (6 months-12 years). Patients with coronary artery disease (CAD) had a significantly lower survival than patients without signs of CAD. Coronary artery disease was significantly more frequent among patients with bilateral carotid lesions compared to patients with unilateral lesions. The actuarial stroke frequency, operative morbidity included, on the operated side was 2.5%/year. However, from 6 months postoperatively up to 8 years the stroke frequency was 1%/year. In the stroke frequencies all neurological deficits of more than 24 h duration are accounted for. Although there was a trend toward higher stroke rates among older patients there were no significant differences between age groups. Assuming a 10% stroke frequency during the first year after a TIA and a 6% annual stroke rate thereafter our results would cross even such a natural course curve at 18 months.

Model studies on acetabular component migration in total hip arthroplasty using CT and a semiautomated program for volume merging

Purpose: Validation of a non-invasive CT method for detection of acetabular cup migration after total hip arthroplasty in a phantom study.

Material and Methods: 26 CT examinations were obtained of a pelvic model while altering the position of the acetabular cup. Using a previously described program for volume merging, the pelvi in different examinations were fused and the 3D alterations of the position of the acetabular cup were evaluated visually and numerically and correlated to direct measurements on the model.

Results: Visually, two independent examiners differentiated between 0, 1 and 2 to 3 mm migration with 100% specificity and sensitivity. Numerically, the mean error over all cases between model and CT measurements was 0.04 mm (SD ± 0.33). The mean absolute error between model and CT data was 0.26 mm (SD ± 0.19). Intra- and interobserver 95% accuracy and repeatability limits were below 0.5/0.7 mm, respectively. No significant interobserver difference occurred. The data were normally distributed and not dependent on observer.

Conclusion: The accuracy of this non-invasive method out-performs routine plain radiography. The method gives both visual and numerical correlates to migration and can be used in clinical practice.

Cerebral arteriovenous malformation and cluster-like headache

Cluster headache is considered a clinically distinct entity with no underlying gross pathology. However, in rare cases this kind of headache may be mimicked by an arteriovenous malformation. A 49-year-old male is described who had severe bouts of unilateral headache resembling those of cluster headache. The usual accompanying autonomic manifestations were minor and the headache attacks were prolonged. Treatment with ergotamine tartrate and pizotifen failed. A large ipsilateral arteriovenous malformation was diagnosed. Prospectively, true clustering of the headache attacks could not be documented.

Three-dimensional movements of the lumbar spine facet joints and segmental movements: in vivo examinations of normal subjects with a new non-invasive method

INTRODUCTION

Examination with CT and image registration is a new technique that we have previously used to assess 3D segmental motions in the lumbar spine in a phantom. Current multi-slice computed tomography (CT) offers highly accurate spatial volume resolution without significant distortion and modern CT scanners makes it possible to reduce the radiation dose to the patients. Our aim was to assess segmental movement in the lumbar spine with the aforementioned method in healthy subjects and also to determine rotation accuracy on phantom vertebrae.

MATERIAL AND METHOD

The subjects were examined in flexion-extension using low dose CT. Eleven healthy, asymptomatic subjects participated in the current study. The subjects were placed on a custom made jig which could provoke the lumbar spine into flexion or extension. CT examination in flexion and extension was performed. The image analysis was performed using a 3D volume fusion tool, registering one of the vertebrae, and then measuring Euler angles and distances in the registered volumes.

RESULTS

The mean 3D facet joint translation at L4-L5 was in the right facet joint 6.1 mm (3.1-8.3), left facet joint 6.9 mm (4.9-9.9), at L5-S1: right facet joint 4.5 mm (1.4-6.9), and for the left facet joint 4.8 mm (2.0-7.7). In subjects the mean angles at the L4-L5 level were: in the sagittal plane 14.3°, coronal plane 0.9° (-0.6 to 2.8), and in the transverse plane 0.6° (-0.4 to 1.5), in the L5-S1 level the rotation was in sagittal plane 10.2° (2.4-16.1), coronal plane 0° (-1.2 to 1.2), and in the transverse plane 0.2° (-0.7 to 0.3). Repeated analysis for 3D facet joint movement was on average 5 mm with a standard error of mean of 0.6 mm and repeatability of 1.8 mm (CI 95%). For segmental rotation in the sagittal plane the mean rotation was 11.5° and standard error of mean 1°. The repeatability for rotation was 2.8° (CI 95%). The accuracy for rotation in the phantom was in the sagittal plane 0.7°, coronal plane 1°, and 0.7 in the transverse plane.

CONCLUSION

This method to assess movement in the lumbar spine is a truly 3D method with a high precision giving both visual and numerical output. We believe that this method for measuring spine movement is useful both in research and in clinical settings.