Treatment products and approaches for phenylketonuria: improved palatability and flexibility demonstrate safety, efficacy and acceptance in US clinical trials

A new amino acid formulation and a variety of treatment products incorporating it were evaluated for long-term safety, efficacy, and acceptance in 25 subjects with phenylketonuria over a period of 5 years. Palatability of the treatment was improved by reducing the required intake of amino acids, reformulating the mixture to have better taste, and providing vitamins and minerals as tablets. The hypotheses were that these strategies would improve compliance and metabolic control and maintain nutritional status in subjects. Compliance with treatment was determined from mean reported intakes (4-day diet records) and from mean 'received' intakes using receipts of treatment products actually shipped to individuals upon request. Mean amino acid intakes prescribed were significantly reduced from study entry to end, from 1.2 g/kg to 0.7 g/kg (p < 0.001). Reported intakes were similarly reduced from 1.3 g/kg to 0.7 g/kg (p < 0.001). While actually 'received' intakes of amino acid formula were also significantly reduced (p < 0.001), intakes by this measure were much lower than either prescribed or reported, 0.9 g/kg at entry and 0.4 g/kg at the end of the study, suggesting that acceptance of the treatment (usage of products), even when made more palatable, is below clinical expectations. In spite of these findings, mean serum proteins and minerals, height and weight were not significantly reduced during the study, supporting the safety of lowered intakes of amino acids and of nutritionally incomplete products. While the increase in mean serum phenylalanine concentration from 0.38 to 0.48 mmol/L was significant (p < 0.03), this mean rise of 0.1 mmol/L during a corresponding mean age increase of 4.2 years (from 6.9 to 11.1 years) is lower than in other recent reports from longitudinal studies of outcomes during this age range in subjects treated with traditional products. These data support the safety and efficacy of a more palatable and flexible approach to treatment.     

Human cytomegalovirus-infected cells have unstable assembly of major histocompatibility complex class I complexes and are resistant to lysis by cytotoxic T lymphocytes

Viruses which cause persistence in the naturally infected host are predicted to have evolved immune evasion mechanisms. Human cytomegalovirus (HCMV) causes significant morbidity and mortality in immunocompromised patients yet persists without clinical manifestations in seropositive individuals who have normal immune function. We report that HCMV infection in vitro impairs major histocompatibility complex class I (MHC-I) assembly accompanied by resistance to killing by cytotoxic CD8+ T lymphocytes. Pulse-chase metabolic labelling experiments show that MHC-I complexes continue to be assembled by both uninfected and HCMV-infected cells. However, MHC-I molecules are unstable in HCMV-infected cells and are rapidly broken down. Endoglycosidase H treatment of immunoprecipitates indicates that the breakdown of MHC-I complexes in HCMV-infected cells occurs primarily in a pre-Golgi compartment. Interference with normal MHC-I assembly and expression, if relevant in vivo, may have implications for the restriction of the diversity of the CD8+ cytotoxic T lymphocyte repertoire directed against HCMV antigens and may be an important mechanism of viral persistence.     

Essential fatty acids, plasma cholesterol, and fat-soluble vitamins in subjects with age-related maculopathy and matched control subjects

A matched-control study of plasma retinol, alpha-tocopherol, carotenoid, and cholesterol concentrations and the polyunsaturated fatty acid content of plasma and erythrocyte phospholipids was undertaken in 65 elderly patients with age-related maculopathy and 65 control subjects matched for age and sex. Despite the high statistical power of the study and large variations between subjects in the variables under consideration, no significant differences were noted between patients and control subjects. However, several statistically significant differences were noted between male and female subjects independent of their classification with maculopathy or as controls and age: plasma cholesterol, total phospholipids, alpha-tocopherol, and beta-cryptoxanthin concentrations were higher in females than in males. The mean plasma cholesterol concentration for the upper tertile of the whole sample was 7.6 mmol/L. Plasma concentrations of total carotenoids, alpha-carotene, and beta-carotene, but not alpha-tocopherol, were significantly lower in smokers than in non-smokers. The results of this study do not provide any evidence in favor of changing the dietary intake of polyunsaturated fatty acids or fat-soluble vitamins to protect against age-related maculopathy.     

Association of proinsulin-like molecules with lipids and fibrinogen in non-diabetic subjects--evidence against a modulating role for insulin

Elevated concentrations of proinsulin-like molecules, other than insulin, may be associated with abnormalities of cardiovascular risk factors, promoting atherogenesis and thrombosis. Using specific assays we examined the relationship of levels of insulin, intact proinsulin and des-31,32 proinsulin to blood pressure, lipids, fibrinogen, factor VII and albumin excretion rate in 270 europids with normal glucose tolerance. After correcting for age and body mass index, fasting and 2-h insulin concentrations were significantly associated with those of total and LDL-cholesterol (r = 0.18-0.22), HDL-cholesterol (both r = -0.20) and triglycerides (r = 0.21 and 0.18), but not with blood pressure. Concentrations of intact and des-31,32 proinsulin showed significant associations with those of total and LDL-cholesterol (r = 0.20-0.23), HDL-cholesterol (r = -0.31 and -0.32) and triglycerides (r = 0.22 and 0.26). Fasting insulin and intact proinsulin concentrations were significantly associated with fibrinogen (r = -0.15 and 0.18). Concentrations of proinsulin-like molecules comprised less than 10% of all insulin-like molecules, and so were calculated not to influence previously described relationships between insulin concentrations and cardiovascular risk factors measured using non-specific assays. In multiple regression analyses des-31,32 proinsulin concentration was more strongly associated with those of HDL-cholesterol (negatively), LDL-cholesterol and triglycerides than fasting insulin concentrations, while intact proinsulin replaced insulin concentrations in their relationships with fibrinogen. Our results show correlations between dyslipidaemia and proinsulin-like molecules at concentrations at which biological, insulin-like, activity appears unlikely. We also show relationships between LDL-cholesterol and fibrinogen and the proinsulin-like molecules.(ABSTRACT TRUNCATED AT 250 WORDS)     

Incidence of transient ischemic attacks and minor ischemic strokes in Segovia, Spain

BACKGROUND AND PURPOSE: The aim of this study was to determine the incidence of transient ischemic attacks (TIAs) and minor ischemic strokes (MISs) in Segovia, Spain. METHODS: A 2-year prospective community-based register of TIAs and MISs established in Segovia from February 16, 1992, to February 15, 1994. Every patient underwent underwent a complete clinical evaluation and cranial CT scan. Sex- and age-specific incidence rates with 95% confidence intervals (CIs) were calculated for all ages. RESULTS: The total series included 235 patients; 103 suffered TIAs and 132 suffered MISs. Mean age was 70.8 years (range, 29 to 96 years); 92 were women and 143 were men. The crude annual incidence was 0.80/1000 (95% CI, 0.70 to 0.90): 0.35/1000 (95% CI, 0.28 to 0.42) for TIAs and 0.45/1000 (95% CI, 0.37 to 0.53) for MISs. The incidence of TIAs and MISs increased with age. Approximately 78 of TIAs and MISs were in the carotid distribution, 19% were vertebrobasilar, and 3% were considered of uncertain vascular distribution. Cranial CT scan was performed in all patients. CT showed cerebral infarcts in 30.1% (31/103; 95% CI, 21% to 39%) of TIAs and 70% (92/132; 95% CI, 62% to 78%) of MISs (P<.00001). CONCLUSIONS: Our study is the first community-based register that provides sex-and age-specific rates for MISs and in which a CT scan was obtained in all patients. The incidence of TIAs in Segovia is comparable to that in other previous similar studies.     

Tubular up-regulation of clusterin mRNA in murine lupus-like nephritis

Clusterin, a widely distributed glycoprotein, is detected in most tissues and in numerous physiological fluids. In the kidney, this protein is constitutively expressed in tubular epithelial cells, and its expression is enhanced following tubular injuries. In addition, clusterin has been detected in glomerular immune deposits of glomerulonephritis. The present study was designed to define the sites of clusterin mRNA accumulation in murine lupus-like nephritis in comparison with murine tubulopathies. In lupus-like nephritis, a significant increase of clusterin mRNA abundance was demonstrated. This up-regulation was localized exclusively in tubular epithelial cells exhibiting tubulointerstitial alterations, whereas no clusterin mRNA was detectable in diseased glomeruli, excluding an active synthesis of clusterin by glomerular cells. A similar tubular increase of clusterin mRNA abundance was observed in myeloma-like cast nephropathy induced by IgG3 monoclonal cryoglobulins and even in the absence of any detectable histological alterations in a model of septic shock induced by the injection of bacterial lipopolysaccharides. Our results suggest that tubular epithelial cells are the only sites of clusterin mRNA accumulation during the course of lupus-like nephritis and that the tubular up-regulation of clusterin gene expression may reflect the cellular response to various types of tubular injuries.     

Manganese toxicity in children receiving long-term parenteral nutrition

BACKGROUND: In patients receiving long-term parenteral nutrition (PN), cholestatic disease and nervous system disorders have been associated with high blood concentrations of manganese. In such patients, the normal homoeostatic mechanisms of the liver and gut are bypassed and the requirement for this trace element is not known; nor has it been certain whether hypermanganesaemia causes the cholestasis or vice versa. We explored the direction of effect by serial tests of liver function after withdrawal of manganese supplements from children receiving long-term PN. We also examined the relation between blood manganese concentrations and brain lesions, as indicated by clinical examination and magnetic resonance imaging (MRI). METHODS: From a combined group of 57 children receiving PN we identified 11 with the combination of hypermanganesaemia and cholestasis; one also had a movement disorder. Manganese supplements were reduced in the first three and withdrawn in the remainder. MRI was done in two of these children. We also looked at manganese concentrations and MRI scans in six children who had received PN for more than 2 years without developing liver disease. FINDINGS: In the hypermanganesaemia/cholestasis group, four of the 11 patients died. In the seven survivors baseline whole-blood manganese was 615-1840 nmol/L, and after 4 months it had declined by a median of 643 nmol/L (p < 0.01). Over the same interval total bilirubin declined by a median of 70 mumol/L (p < 0.05). Two of these children had movement disorders, one of whom survived to have an MRI scan; this showed, with T1 weighted images, bilateral symmetrically increased signal intensity in the globus pallidus and subthalamic nuclei. Such changes were also seen in five other children--one from the hypermanganesaemia/cholestasis group and four of six in the long-term PN group without liver disease (in all of whom blood manganese was above normal). INTERPRETATION: The cholestasis complicating PN is multifactorial, but these results add to the evidence that manganese contributes. In view of the additional hazard of basal ganglia damage from high manganese levels in children receiving long-term PN, we recommend a low dose regimen of not more than 0.018 mumol/kg per 24 h together with regular examination of the nervous system.