Clinical delineation and natural history of the PIK3CA-related overgrowth spectrum

Somatic mutations in the phosphatidylinositol/AKT/mTOR pathway cause segmental overgrowth disorders. Diagnostic descriptors associated with PIK3CA mutations include fibroadipose overgrowth (FAO), Hemihyperplasia multiple Lipomatosis (HHML), Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi, Scoliosis/skeletal and spinal (CLOVES) syndrome, macrodactyly, and the megalencephaly syndrome, Megalencephaly-Capillary malformation (MCAP) syndrome. We set out to refine the understanding of the clinical spectrum and natural history of these phenotypes, and now describe 35 patients with segmental overgrowth and somatic PIK3CA mutations. The phenotypic data show that these previously described disease entities have considerable overlap, and represent a spectrum. While this spectrum overlaps with Proteus syndrome (sporadic, mosaic, and progressive) it can be distinguished by the absence of cerebriform connective tissue nevi and a distinct natural history. Vascular malformations were found in 15/35 (43%) and epidermal nevi in 4/35 (11%) patients, lower than in Proteus syndrome. Unlike Proteus syndrome, 31/35 (89%) patients with PIK3CA mutations had congenital overgrowth, and in 35/35 patients this was asymmetric and disproportionate. Overgrowth was mild with little postnatal progression in most, while in others it was severe and progressive requiring multiple surgeries. Novel findings include: adipose dysregulation present in all patients, unilateral overgrowth that is predominantly left-sided, overgrowth that affects the lower extremities more than the upper extremities and progresses in a distal to proximal pattern, and in the most severely affected patients is associated with marked paucity of adipose tissue in unaffected areas. While the current data are consistent with some genotype-phenotype correlation, this cannot yet be confirmed.

Isolation and characterisation of a linked cluster of genes from Agrobacterium tumefaciens encoding proteins involved in flagellar basal-body structure

We report the DNA sequence of 7205 bp of the Agrobacterium tumefaciens chromosome. This contains a putative operon encoding homologues of the flagellar rod and associated proteins FlgBCG and FliE, the L and P ring proteins (FlgHI) a possible flagellum-specific export protein FliP, and two proteins of unknown function, FlgA and FliL. Several of these genes have overlapping stop and start codons. Three non-flagellate Tn5-induced mutations map to this operon: fla-11 to the first gene, encoding the rod protein FlgB; fla-15 to flgA; and fla-12 to fliL. A site-specific mutation introduced into the final gene in this cluster, fliP, also resulted in a non-flagellate phenotype. This indicates that the operon is expressed, and that at least FlgB, FlgA, FliL and FliP are required for flagellar assembly in A. tumefaciens. The bulk of this operon is conserved in the same order in Rhizobium meliloti.

Comparative dosing and efficacy of continuous-release nifedipine versus standard nifedipine for angina pectoris: clinical response, exercise performance, and plasma nifedipine levels

To assess the dosing equivalency and the early and late antianginal efficacy of a gastrointestinal therapeutic system for once-daily, continuous-release nifedipine (N-GITS), 10 patients with stable angina pectoris, who were previously receiving chronic treatment with nifedipine, completed a 12-week trial comparing N-GITS with standard nifedipine. All patients (nine men and one woman; mean age 54 +/- 2 [SEM] years) who were receiving standard nifedipine (mean dose 40 +/- 5 mg/24 hr) for more than 2 weeks (mean 8 +/- 2 months, range 2 to 36 months) were switched to an equivalent once-daily dose (39 +/- 5 mg/24 hr) of N-GITS. Standard nifedipine and N-GITS were compared by symptom-limited exercise treadmill tests with a baseline test (A) performed 3 hours after a standard dose of nifedipine. Exercise tests were also performed after 2 weeks of treatment with N-GITS 3 hours (B) and 24 hours (C) after the drug was given, and after 12 weeks of treatment with N-GITS, 24 hours after dosing (D). Results of exercise tests showed no significant difference in mean exercise time--(A) 422 +/- 25 vs (B) 426 +/- 36 vs (C) 438 +/- 35 vs (D) 487 +/- 37 seconds. Likewise, there was no significant mean difference in peak double product, resting heart rate, peak exercise heart rate, or resting or maximal systolic blood pressure for any of the exercise test points. Furthermore, five patients (50%) reported side effects with standard nifedipine (all vasodilator-flushing, dizziness, or both), which resolved after treatment with N-GITS (p +/- 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Nifedipine gastrointestinal therapeutic system in stable angina pectoris. Results of a multicenter open-label crossover comparison with standard nifedipine

To compare the clinical efficacy and dose equivalency of standard nifedipine versus a new gastrointestinal therapeutic system (GITS) formulation of nifedipine, 98 patients with chronic stable angina pectoris participated in a 14-week, multicenter, open-label, crossover trial. All patients were administered nifedipine capsules for one month prior to study entry and continued receiving other antianginal, non-calcium blocker medications. Ninety-one patients (93 percent), 80 men and 11 women, mean age 62 +/- 1 years, completed the trial, which included two weeks receiving standard nifedipine followed by 12 weeks receiving nifedipine GITS starting at a dosage equal to the 24-hour total dose of nifedipine capsules and titrated upward as necessary. However, throughout the trial, mean nifedipine dosage was similar on nifedipine GITS compared with standard nifedipine. Angina frequency was significantly less with nifedipine GITS at Weeks 6, 10, and 14 (0.8 episodes/week) compared with baseline with standard nifedipine (1.3 episodes/week, p less than 0.05). Likewise, nitroglycerin consumption was also less at Weeks 6, 10, and 14, but only significantly less at Week 6 (nifedipine 1.2/week versus nifedipine GITS at six weeks, 0.7/week; p less than 0.05). Resting hemodynamic parameters, including systolic and diastolic blood pressure and heart rate, were not significantly different with standard nifedipine versus nifedipine GITS during the 12-week study. Total incidences of side effects were similar for both treatments (standard nifedipine, 16; nifedipine GITS, 17). However, incidence of vasodilator side effects (flushing, dizziness, and light-headedness) was significantly less frequent with nifedipine GITS (standard nifedipine, 12; nifedipine GITS, six; p less than 0.05). Thus, results from this open-label, crossover trial suggest that nifedipine GITS dosing is similar to multidose standard nifedipine with equivalent 24-hour efficacy for nifedipine GITS.

Alternative medical treatment for patients with angina pectoris and adverse reactions to beta blockers. Usefulness of nifedipine

Although beta blockers are effective for the treatment of angina pectoris, chronic adverse effects produced by these agents--including lethargy, fatigue, and male impotence--can adversely affect patient acceptance and treatment compliance. To assess the clinical effects of switching from anti-anginal treatment with beta blocker only (phase I) to half-dose beta blocker plus the calcium blocker nifedipine (phase II) or nifedipine alone (phase III), 18 patients with chronic stable angina pectoris and side effects to beta blockers were evaluated in a 12-week, open-label trial. Three patients did not complete the study, one secondary to new unstable angina and two secondary to nifedipine side effects. Of the 15 patients completing the trial (13 men and two women; mean age, 54 +/- 5 [SEM] years), all sequentially participated in the one-month phases. Weekly angina frequency assessed from patient diaries was significantly less for treatment with nifedipine only (phase III) as compared with beta blocker (phase I) (1.7 +/- 1 versus 3.9 +/- 1 episodes per week), while phase II was not significantly different. Exercise test time was maintained throughout all phases (phase I, 457 +/- 39; phase II, 458 +/- 40; and phase III, 498 +/- 48 seconds, p not significant). All 15 patients in phase I (100 percent) had side effects to beta blockers, but these side effects were lessened in 12 patients (80 percent) in phase II and 13 patients (86 percent) in phase III, with total alleviation of symptoms in two patients (13 percent) in phase II, and eight patients (53 percent) in phase III. Thus, in patients with side effects to beta blockers, switching to nifedipine is associated with a significant reduction in beta blocker adverse symptoms and equal anti-anginal efficacy.

Acute electrophysiologic, hemodynamic and left ventricular effects of nifedipine and beta-blocker interactions. Maintenance of global and regional left ventricular wall motion

To assess potential cardiac effects of nifedipine and beta-blocker interactions, 10 men receiving chronic beta-blocker therapy for angina underwent hemodynamic, electrophysiologic and left ventricular (LV) functional analyses at the time of cardiac catheterization before and after buccal administration of 10 mg of nifedipine. Although this combination is usually well tolerated, there have been occasional reports suggesting that the combination of nifedipine and beta-blocking agents may increase the likelihood of congestive heart failure, severe hypotension or exacerbation of angina. All patients had class II or III stable angina pectoris and were receiving at least 160 to 240 mg/day of propranolol or equivalent doses of beta-blocker therapy. Nifedipine produced no acute electrophysiologic changes, including heart rate, PR interval, AH interval, HV interval, sinus node recovery time or heart rate at which atrioventricular nodal block occurred. Hemodynamic effects included no significant change in mean right atrial pressure (7 +/- 1 vs 5 +/- 1 mm Hg), while mean pulmonary artery pressure decreased significantly (20 +/- 2 vs 17 +/- 1 mm Hg, p less than or equal to 0.05). In addition, LV end-diastolic pressure decreased significantly from 16 +/- 2 to 10 +/- 1 mm Hg (p less than or equal to 0.05), with a nonsignificant decrease in mean aortic pressure from 93 +/- 5 to 86 +/- 4 mm Hg. Likewise, no significant change occurred in cardiac index (3.2 +/- 0.4 vs 3.0 +/- 0.4 liters/min/m2) or systemic vascular resistance (1,157 +/- 247 vs 1,170 +/- 236 dynes/s/cm-5). Left ventricular ejection fraction (EF) was the same before and after nifedipine (73 +/- 2% vs 74 +/- 2%).(ABSTRACT TRUNCATED AT 250 WORDS)