A new amino acid mixture permits new approaches to the treatment of phenylketonuria

A new amino acid mixture for incorporation into medical foods for the treatment of hyperphenylalaninemia has been tested in a regular clinic. The mix is designed to be as unobtrusive as possible, consistent with good nutrition. After more than 1 year of trial as a beverage, we have shown that it is safe and well tolerated but that plasma phenylalanine is no better controlled than with some other products. The mix can be incorporated into a large number of different foods without affecting the taste. Occult monitoring of the quantity of medical foods purchased compared with the amounts reported to be consumed in diet histories provides an excellent way to monitor dietary compliance.     

Supraacetabular insufficiency fractures

Insufficiency fractures in the supraacetabular region were identified in five women, aged 55-83 years. Factors contributing to the diminished resistance of their bones included postmenopausal osteoporosis, steroid therapy, radiation therapy, and rheumatoid arthritis. The supraacetabular fractures were seen on routine radiographs as hazy bands of sclerosis located immediately above and parallel to the acetabular roof. All five patients had additional fractures in the spine or pelvis. Supraacetabular insufficiency fractures may be an unsuspected cause of hip pain, especially in older women.     

Hypothalamic opioids and the acute-phase glycoprotein response in guinea pigs

Endogenous opioids (EO) probably do not modulate endotoxin (LPS)- or interleukin 1 (IL1)-induced fever because naloxone does not prevent its development. Yet, increases in CSF and hypothalamic levels of beta-endorphin have been reported during LPS-and IL1-induced fevers. Since IL1 also reduces the specific binding of opioids to their receptors in guinea pig brain, the opioids could be involved in modulating nonfebrile effects of IL1. To determine whether EO might have a role in the IL1-induced acute-phase glycoprotein response of guinea pigs, (1) naloxone (5 and 10 mg/kg, SC) was injected prior to LPS (S. enteritidis 2 micrograms/kg, IV; N = 5), and (2) morphine (MOR, 10 micrograms/microliter), [D-ala2]-met-enkephalinamide (DAME, 5 micrograms/microliter), or dynorphin A (DYN, 5 micrograms/microliter) was injected into the preoptic area (1 microliter, bilaterally; N = 8/treatment) or into the 3rd ventricle (N = 4/treatment); pyrogen-free saline was the control injection. Measurements were: core temperature (Tco) and, as indices of acute-phase glycoproteins, plasma levels of copper (Cu) and N-acetylneuraminic acid (NANA). Naloxone did not prevent the fever or the increases in plasma Cu and NANA levels evoked by LPS. The intracerebral administration of opioid agonists by either route induced variable rises in Tco, each with a different pattern, but no increases in plasma Cu and NANA levels. Thus, EO do not participate in the central modulation of acute-phase glycoprotein synthesis, but may have a role in influencing other nonthermal IL1 effects in the CNS.     

Ductal Anatomy

Interventional palliation for hypoplastic left heart syndrome (HLHS) could reduce the current morbidity and mortality. Stenting of the arterial duct is the critical interventional step for HLHS. We reviewed our experience with 40 consecutive patients with HLHS referred for stenting of the ductus arterious (DA). Thirty-nine of 40 (97%) infants had suitable anatomy and were successfully stented. The infants were grouped by orientation of the ductus in the frontal plane. Type 1 DA anatomy had a leftward loop at a mean orientation of 18° from the vertical plane. Type 2 ductal anatomy was mesoverted, with a mean orientation of 7.1° from the vertical plane. Type 3 ductal anatomy displayed a rightward axis, with a mean of -4° rightward. Orientation of the DA was significantly related to length of the ductus, number of stents required for complete coverage, and technical and procedural complications. Type 1 DA occurred in 65% of patients, and there was 100% technical success, no mortality, and only an 8% incidence of complications. Type 2 anatomy occurred in 27% of patients and there was 100% success. However, the technical and procedural complications increased to approximately 50%. Type 3 ductal anatomy was seen in only 3 patients, 2 of whom were successfully stented. There was no procedural-related mortality, and all stented patients were weaned from prostaglandin. There were only two late complications (coarctation). We conclude that ductal stenting using self-expanding nitinol stents is successful in more than 95% of infants with HLHS. Patients with HLHS and favorable ductal anatomy should be considered for primary ductal stenting.     

Modulation of the human Kv1.5 channel by protein kinase C activation: role of the Kvbeta1.2 subunit

Kv1.5 is the principal molecular component of I(Kur), an atrial-specific K(+) current in human myocytes that is suppressed by activation of protein kinase C (PKC). We examined the effect of phorbol 12-myristate 13-acetate (PMA), a direct activator of PKC, on Kv1.5 current. Although PMA had minimal effect when Kv1.5 was expressed alone, K(+) currents derived from coexpression of Kvbeta1.2 (but not another closely related beta subunit, Kvbeta1.3) with Kv1.5 were markedly reduced by PMA, associated with a small depolarizing shift in the voltage dependence of channel activation. Additional experiments with an inactive stereoisomer, 4alpha-PMA, and the PKC inhibitor chelerythrine indicated that the effects of PMA were mediated by PKC activation. Assembly of Kv1.5 in vivo with both beta subunits was demonstrated, and all three K(+) channel proteins were substrates for phosphorylation by PKC. These results demonstrate that coexpression of Kvbeta1.2 enhances the response of Kv1.5 to PKC activation and that direct phosphorylation of K(+) channel subunits is a potential molecular basis for the effect. Furthermore, they suggest that Kvbeta1.2 may be a component of the I(Kur) complex in human atrium.     

Beta2 integrin/ICAM-1 adhesion molecule interactions in cutaneous inflammation and tumor promotion

The beta2 integrin (CD 18/CD 11 a, b, c) family of proteins mediate adherence of leukocytes to vascular endothelium and the associated ligand, intercellular adhesion molecule-1 (ICAM-1; CD 54), interacts with beta2 integrin proteins to allow transendothelial migration of leukocytes into sites of inflammation. The present study examines the function of these proteins in a murine model of acute cutaneous inflammation induced following topical application of 12-O- tetradecanoylphorbol-13-acetate (TPA) to the dorsal epidermis of SENCAR mice and in a model of skin multistage carcinogenesis. At 24 h following topical application of TPA to the dorsal epidermis of mice, dermal leukocytes expressed higher levels of beta2 integrin protein compared with the lower levels of beta2 integrin protein expression by peripheral blood leukocytes. ICAM-1 protein was localized to epidermal keratinocytes and vascular endothelium in TPA-treated skin and to proliferating papilloma cells. Intravenous (i.v.) injection of either 50 microg anti-beta2 integrin antibody alone or in combination with anti-ICAM-1 antibody significantly inhibited both TPA-stimulated neutrophil infiltration into the dermis (P < 0.001) and myeloperoxidase (MPO) activity (P < 0.03 anti-beta2 integrin antibody; P < 0.01 anti- beta2 integrin + ICAM-1 adhesion molecule antibodies), but had no effect on TPA-induced epidermal hyperplasia. In addition, injection of either anti-ICAM-1 adhesion molecule antibody alone (P < 0.004) or in combination with anti-beta2 integrin antibody (P < 0.001) significantly inhibited TPA-induced production of 7,8-dihydroxy-2'-deoxyguanosine (8- OHdG) immunoreactive proteins by epidermal keratinocytes. Beta2 integrin/ICAM-1 adhesion molecules work in concert to regulate migration, retention and functional activation of leukocytes within the dermis during TPA-induced skin inflammation and within stromal tissue of papillomas that form during multi-stage carcinogenesis. Agents that inhibit these receptor/ligand interactions may be useful in defining the roles of specific cell populations in cutaneous inflammation and multistage carcinogenesis and may also have potential as anti-promoting and anti-progression agents.      

Efficacy of "high-intensity" blue-light and "standard" daylight phototherapy for non-haemolytic hyperbilirubinaemia

We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy.     

Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome, two hamartoma syndromes with germline PTEN mutation

The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.