Abnormal regulation of the LDL-R and HMG CoA reductase genes in subjects with familial hypercholesterolemia with the "French Canadian mutation"

Familial hypercholesterolemia (FH) is seen with high frequency in the province of Québec, Canada. A large deletion (> 10 kb) of the 5'-end of the low density lipoprotein receptor (LDL-R) gene is the major mutation of the LDL-R in FH subjects in Québec (approximately 60% of FH subjects). No mRNA is produced from the allele bearing the mutation, and cellular cholesterol obtained by receptor-mediated endocytosis is under the control of the non-deletion allele. We have previously reported that some patients with the 10-kb deletion (approximately 9%) fail to respond to the hydroxymethylglutaryl coenzyme A reductase (HMG CoA reductase) inhibitor class of medications. We studied mRNA levels of the LDL-R and HMG CoA reductase genes in response to the HMG CoA reductase inhibitor lovastatin in a time- and dose-dependent fashion in cultured human skin fibroblasts and we devised an in vitro model to study the response to drug therapy in subjects with FH. We determined mRNA levels by RNase protection assay in skin fibroblasts obtained from controls (n = 3) and FH subjects with the > 10-kb deletion (responders, n = 3; non responders, n = 3; to drug therapy). We measured 125I-LDL binding on skin fibroblasts grown in the presence of lipoprotein-deficient serum with or without 1 microM lovastatin, using 10 micrograms/mL of 125I-LDL protein. Control subjects exhibited coordinate regulation of the LDL-R and HMG CoA reductase genes in response to lovastatin, 0.1-25 microM, for 0-24 h. Correlation coefficients between mRNA levels of both genes were > 0.9 in controls and FH subjects. However, by linear regression analysis, the corresponding slopes for the correlation between both genes were 0.98 (controls), 3.36 and 3.63 (FH responders and non-responders), indicating a pattern of dissociated but still coordinate regulation in FH subjects. The magnitude of increase of mRNA levels of the LDL-R gene was approximately five-fold over LPDS in controls, two-fold in FH responders and two-fold in non-responders. Binding studies using 125I-LDL reveal that a control subject and all responders had a 2-2.5-fold increase in binding to cell surface receptors but two out of three FH non-responders showed no increase in binding in response to 1 microM lovastatin. The LDL-R and HMG CoA reductase genes are expressed in coordinate regulation in fibroblasts from subjects with FH due to the > 10-kb deletion, but with a proportionately greater up-regulation of the HMG CoA reductase gene. Some subjects, with FH caused by the > 10-kb deletion of the LDL-R gene, who fail to respond to HMG CoA reductase inhibitors have abnormal LDL receptor binding activity at the cell surface in response to lovastatin in vitro.

[A morphological study of degenerative mechanism of articular cartilage by abnormal high stress]

The articular cartilage from the right knee of 87 rats whose left calcaneal tendons had been transected was examined under transmission and scanning electron microscopes, and light microscope. Morphological observation showed a few small focal areas of cartilage surface disruption, pit and collagen fibrillation at 2 weeks after operation. After 1 month, many clusters of chondrocytes could be found, showing hyperactive synthetic and secretary activity. The cartilage degenerated progressively. The initial lesion in high stress side was at the matrix of cartilage, the collagen network was disrupted, then proteoglycan become degraded. The microenvironment of chondrocytes was changed with degradation of matrix. The chondrocytes became degenerative. The degeneration of chondrocytes influence the matrix again. A vicious cycle was thus formed. At the early stage of the degeneration of the cartilage induced by high-stress, som chondrocytes proliferate and have hyperactive synthetic and secretive functional activity. But soon, most of the chondrocytes degenerate. That is because of the chondrocytes have got repaired in response to initial matrix lesion and the normal microenvironment had degraded with aggravation of matrix lesion. These chondrocytes again became degenerative quickly.

[A comparative study of effects on bone healing and remodelling between embracing fixator and bone]

The authors made their own design of sawteeth-arm embracing internal fixator (SEIF) with NiTi shape memory alloy and used for fractured femoral shaft of dogs in comparison with 316L stainless steel plate-screw system. A transverse osteotomy on both sides of femoral diaphyses was performed in 15 adult dogs. One side was plated with bone plate and the other with SEIF. Five animals in each group were killed at 4, 8, 12 weeks after operation and observed under roentgen rays examination, light microscopy and transmission electron microscopy. The results showed that the fracture healing and the course of callus remodelling were similar in these two groups, but the cortical bone remodelling underneath the fixater near osteotomized area was significantly different. Eight-week post-implantation, osteocytes entered into degenerative phase were observed in cortical bone underneath SEIF, and 12-week after operation, the numbers of degenerative osteocytes increased remarkably. While in the case of bone plate, 4-week post-implantation, osteocytes entered into degenerative phase, and 8-week afterwards autolysis occurred in most of the degenerative osteocyles. In other words, the changes of osteocytes phase in bone plate side appeared earlier and more vigorous than that in the SEIF side. The authors are of the opinion that the elastic modulus of NiTi shape memory alloy is lower, the stress-shielding effect in the bone underneath SEIF is less, the axial compression stress of fracture line is kept larger and the contact of SEIF with the bone is not so close that is beneficial to the recovery of blood supply and bone remodelling.

[Clinical application of silica ball implant enclosed by an autologous reversal sclera in patients with enucleation]

PURPOSE

To observe the effects of improved silica ball implantation enclosed by autologous reversal sclera.

METHODS

After the enucleation of eye balls, we reversed, cleared the autologous sclera, enclosed the silica ball and implanted it in the operative eye.

RESULTS

30 cases with enucleation were implanted the prosthetic eyes. The follow-up period was 6 months to 3 years. The prosthetic eyes had the motility of 10 degrees to 25 degrees and the empty socket syndrome was effectively prevented.

CONCLUSION

The sargical method can overcome the defect that prosthetic eyes cannot rotate after being implanted and has got satisfactory cosmetic effects.

[Fecundify after treatment of tubal pregnancy]

This study is a follow-up analysis of 103 patients who desired to preserve their fertile ability after treatment of tubal pregnancy. Among the 103 cases, 58 were treated by unilateral salpingectomy, 15 by salpingostomy and 30 by drug conservative therapy.

RESULTS

67 cases had intrauterine pregnancy and 9 cases repeated ectopic pregnancy. The intrauterine pregnancy rate of the surgical group (71.2%) was higher than that of the nonsurgical group (50.0%). And the pregnancy rate of salpingostomy group (86.7%) was higher than that of salpingectomy group (67.2%). No repeated ectopic pregnancy occurred in the salpingostomy group. After three months of treatment, 45 cases were randomly sampled for tubal patency test. Bilateral tubal patency rate in salpingostomy group was 93.3% and in drug treatment group was 20.0%. These results indicated that tubal patency is an essential factor for normal pregnancy. Prevention of post-operative adhesion and treatment of pelvic inflammatory disease are important for increasing intrauterine pregnancy rate and decreasing repeated ectopic pregnancy rate.

An overview of the CERC ARTEMIS project

The basic premise of this effort is that health care can be made more effective and affordable by applying modern computer technology to improve collaboration among diverse and distributed health care providers. Information sharing, communication, and coordination are basic elements of any collaborative endeavor. In the health care domain, collaboration is characterized by cooperative activities by health care providers to deliver total and real-time care for their patients. Communication between providers and managed access to distributed patient records should enable health care providers to make informed decisions about their patients in a timely manner. With an effective medical information infrastructure in place, a patient will be able to visit any health care provider with access to the network, and the provider will be able to use relevant information from even the last episode of care in the patient record. Such a patient-centered perspective is in keeping with the real mission of health care providers. Today, an easy-to-use, integrated health care network is not in place in any community, even though current technology makes such a network possible. Large health care systems have deployed partial and disparate systems that address different elements of collaboration. But these islands of automation have not been integrated to facilitate cooperation among health care providers in large communities or nationally. CERC and its team members at Valley Health Systems, Inc., St. Marys Hospital and Cabell Huntington Hospital form a consortium committed to improving collaboration among the diverse and distributed providers in the health care arena. As the first contract recipient of the multi-agency High Performance Computing and Communications (HPCC) Initiative, this team of computer system developers, practicing rural physicians, community care groups, health care researchers, and tertiary care providers are using research prototypes and commercial off-the-shelf technologies to develop an open collaboration environment for the health care domain. This environment is called ARTEMIS--Advanced Research TEstbed for Medical InformaticS.

[Careful dissection of the pelvic plexus helps alleviate urinary retention following radical hysterectomy]

Radical hysterectomy remains to be the treatment of choice for carcinoma of the uterine cervix. As pelvic nerve plexuses are distributed in the operative field, damage to the plexuses is likely to occur, which is responsible for the post-operative atonia of the urinary bladder and urinary retention. To reduce the incidence of this postoperative complication, the composition and distribution of the pelvic nerve plexuses in relation to the utero-sacral ligament and cardinal ligament of the uterus and paravaginal tissues were carefully dissected on 11 adult female cadavers. Based on the anatomic study, due precautions were made to avoid damage to the pelvic nerve plexuses during pelvic dissection for radical hysterectomy. As a result, the duration of postoperative urinary retention was significantly reduced while the 5- and 10-year survival rates remained unchanged.

Response to HMG CoA reductase inhibitors in heterozygous familial hypercholesterolemia due to the 10-kb deletion ("French Canadian mutation") of the LDL receptor gene

The 10-kb deletion ("French Canadian mutation") of the low-density lipoprotein (LDL) receptor gene is the most common mutation causing familial hypercholesterolemia among subjects of French Canadian descent. In affected subjects, it results in a null allele of the LDL receptor gene and provides a unique opportunity to examine single-allele regulation of this gene in humans. We sought to ascertain the response of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase in subjects with the French Canadian mutation of the LDL receptor gene and to correlate this response with biochemical variables and the haplotype of the nondeletion LDL receptor allele. The prevalence of non-responders to high doses of HMG CoA reductase inhibitors (defined as < 15% decrease in LDL cholesterol [LDL-C] from baseline values after dietary intervention) was ascertained in 105 patients heterozygous for the 10-kb deletion after excluding first-degree relatives and those on combined lipid-lowering therapy or other lipid-lowering agents. Lipoprotein cholesterol levels were examined after a diet period (30% calories as fat) and after receiving HMG CoA reductase inhibitors as mono-therapy for a minimum of 3 months. The mean reduction in total cholesterol was 45 +/- 23%, in LDL-C 33 +/- 15%, and in triglycerides 32 +/- 49% (all P < .005). There was a slight increase in high-density lipoprotein cholesterol of 8.5 +/- 18% (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aspirin versus heparin to prevent myocardial infarction during the acute phase of unstable angina

BACKGROUND

Antiplatelet therapy with aspirin and antithrombotic therapy with heparin both prevent the complications of unstable angina; however, no definitive data exist on the relative clinical efficacy of the two drugs.

METHODS AND RESULTS

Aspirin (325 mg bid) or heparin (5000-U intravenous bolus followed by a perfusion titrated to the APTT) were compared in a double-blind randomized trial of 484 patients in two cohorts enrolled sequentially. The study was initiated at admission to hospital at a mean of 8.3 +/- 7.8 hours after the last episode of pain. End points were assessed 5.7 +/- 3.3 days later, when the decision for long-term management was made. Myocardial infarction occurred in 2 (0.8%) of the 240 patients randomized to heparin and in 9 (3.7%) of the 244 randomized to aspirin (P = .035), an odds ratio of 0.22 and a risk difference of 2.9% (95% confidence limits, 0.3% to 5.6%) with heparin. The only death resulted from a myocardial infarction in an aspirin patient. Survival curves with Cox logistic regression analysis showed that the improvement in survival without myocardial infarction with heparin (P = .035) was independent of other baseline characteristics.

CONCLUSIONS

This study documents that heparin prevents myocardial infarction better than aspirin during the acute phase of unstable angina.

[Clinical analysis of the outcome of pregnancy with chronic renal disease]

Seventy-six cases of pregnancy with chronic renal disease, from Jan. 1971 to April 1992, were analysed. According to the value of serum creatinine, these cases were divided into four groups, i.e. normal, mild, moderate and severe renal insufficiency. The pregnancy outcome in the first two groups was satisfactory and that in the moderate and severe groups were poor. The prognosis was even worse when it complicated by chronic hypertension. Among the last two groups, 78.8% cases had superimposed preeclampsia, and 24.2% had deteriorated renal function. The perinatal mortality rate was 121.2/1000. The results suggested that the prognosis for mother and maternity baby is closely related to mother's renal function and whether chronic hypertension is complicated preeclampsia is the direct factor resulting deterioration of renal function. It was considered that if serum creatinine > 132.6 mumol/L and complicated by chronic hypertension, pregnancy must be avoided. If renal function is deteriorating, pregnancy must be interrupted.

[Antimicrobial activity of clarithromycin and its effect on bacterial adherence to medical material]

Antimicrobial activity of clarithromycin (CAM) in comparison with other 6 macrolides was determined against 419 recent clinical isolates including Streptococci, Enterococci, Staphylococci, Moraxella, Haemophilus and Bacteroides strains. MICs80's of CAM against Streptococcus pneumoniae, Streptococcus pyogenes and Streptococcus agalactiae were 0.78, 0.10 and 0.10 microgram/ml, respectively. MICs80's against Moraxella catarrhalis and Haemophilus influenzae were 0.05 and 1.56 micrograms/ml, respectively. Laboratory-induced resistance to CAM in strains of S. pneumoniae, Enterococcus faecalis or methicillin-sensitive Staphylococcus epidermidis occurred in stepwise fashion and at a very low rate. Adherence to silicon filter of strains of Pseudomonas aeruginosa or S. epidermidis was strongly repressed by the addition of sub-MIC of CAM or other macrolides. Although tosufloxacin (TFLX) alone had no bactericidal activity against the sessile cells of P. aeruginosa strains tested, TFLX showed synergistic bactericidal activity when combined with sub-MICs of CAM or erythromycin.

Plasma endothelin-1 levels in stable and unstable angina

Plasma levels of endothelin-1 are elevated in acute myocardial infarction with higher levels in complicated infarctions. Measurements of levels in unstable angina could help clarify whether the elevation is the consequence of cell necrosis or is in some way related to the pathophysiology of acute coronary syndromes. Plasma endothelin-1 levels were determined by radioimmunoassay in 29 patients with unstable angina and 6 with a myocardial infarction. Blood samples were obtained at admission before drug administration and 6 and 72 h later. Levels were also determined in 27 control subjects and in 29 patients with stable angina. Admission levels were similar in unstable angina, 0.635 +/- 0.052 pg/ml [log(1 + x)], and myocardial infarction, 0.746 +/- 0.122, and significantly higher than in controls, 0.428 +/- 0.047, and stable angina patients, 0.449 +/- 0.052 (p < 0.01). In unstable angina, levels decreased progressively to normal at 6 h, 0.557 +/- 0.049 pg/ml, and 72 h 0.474 +/- 0.054, as opposed to an increase to 0.868 +/- 0.109 (p < 0.05) after 6 h in myocardial infarction followed by a decrease to 0.597 +/- 0.122 at 72 h. The elevation in unstable angina did not correlate with other clinical or laboratory characteristics. Unstable angina is associated with an increase in endothelin-1 plasma levels during the acute phase, suggesting a role of this endothelium-derived vasoactive peptide in the pathophysiology of acute coronary artery syndromes.

[Effect of radix Astragali and radix ginseng in enhancing the metabolism of human myocardial cells in vitro]

Our experiment indicated that in Radix Astragali and Radix Ginseng treated human myocardial cell cultures the level of LDH and SDH elevated in varying degrees and in Radix Ginseng treated cells the cAMP showed higher levels but in Radix Ginseng treated ones the same was not observed. This suggests that the metabolism of myocardial cells is enhanced by Radix Astragali or Radix Ginseng.

[Microscopic study of the arch structure of trabeculae in normal and necrotic femoral heads]

The trabeculae structure in normal and necrotic femoral heads was studied by means of scanning electron microscope. In normal femoral heads, most of the trabeculae were seen in the form of arch structure, and in which the mineral columns were arranged in different directions on different layers. In necrotic femoral heads, the arch structure of trabeculae and the arrangement of the mineral columns over unresorbed area were practically normal, but over the resorbed area, the arch structure of trabeculae was broken and collapsed, and the mineral columns were sparse and disorganized. These findings provide a new explanation of the capability of the femoral head to bear high stress and also of the mechanism of its collapse after necrosis.