Comparison of Three Approaches to Teaching Reading Skills

Linguistic, look-say, and special alphabet approaches to teaching initial reading skills were compared among 814 beginning first grade children of equivalent readiness levels. Wide Range Achievement Test reading scores at the end of first grade showed a significant superiority of the special alphabet approach, with the linguistic approach also significantly more effective than the more traditional look-say procedure.

Matrix metalloproteinase inhibition modifies left ventricular remodeling after myocardial infarction in pigs

BACKGROUND

Global and regional shape changes that occur within the left ventricular wall after myocardial infarction have been termed infarct expansion. A potential mechanism for this postinfarction remodeling is activation of the matrix metalloproteinases. Accordingly, the present study examined the effects of matrix metalloproteinase inhibition on left ventricular global geometry after myocardial infarction in pigs.

METHODS

Myocardial infarction was created in pigs by means of occlusion of the first and second obtuse marginal branches of the circumflex coronary artery, resulting in a uniform left ventricular free wall infarct size of 21% +/- 2%. At 5 days after infarction, the pigs were randomized to undergo broad-spectrum matrix metalloproteinase inhibition (n = 9; PD166793, 20 mg. kg(-1). d(-1) by mouth) or myocardial infarction alone (n = 8). Ten pigs served as noninfarction control animals. Left ventricular end-diastolic area, determined by means of echocardiography, was measured 8 weeks after infarction.

RESULTS

Left ventricular end-diastolic area increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and myocardial infarction only groups compared to reference control animals (3.7 +/- 0.2 cm(2)), but was reduced with broad-spectrum matrix metalloproteinase inhibition compared to myocardial infarction alone (4.5 +/- 0.2 vs 4.9 +/- 0.2 cm(2), respectively; P <.05). Regional radial stress within the infarct region increased in both infarction groups when compared to values obtained from reference control animals (599 +/- 152 g/cm(2)), but was attenuated in the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition group compared to the myocardial infarction alone group (663 +/- 108 vs 1242 +/- 251 g/cm(2), respectively; P <.05). Similarly, regional myocardial stiffness increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and the myocardial infarction only groups compared with that observed in reference control animals (14 +/- 1 rkm, P <.05) but was lower with broad-spectrum matrix metalloproteinase inhibition than with myocardial infarction alone (42 +/- 6 vs 68 +/- 10 rkm, respectively; P <.05).

CONCLUSIONS

Matrix metalloproteinase inhibition reduced postinfarction left ventricular dilation, reduced regional myocardial wall stress, and modified myocardial material properties. These unique findings suggest that increased myocardial matrix metalloproteinase activation after infarction contributes directly to the left ventricular remodeling process.

Myocardial infarct expansion and matrix metalloproteinase inhibition

BACKGROUND

A potential mechanism for left ventricular (LV) remodeling after myocardial infarction (MI) is activation of the matrix metalloproteinases (MMPs). This study examined the effects of MMP inhibition (MMPi) on regional LV geometry and MMP levels after MI.

METHODS AND RESULTS

In pigs instrumented with radiopaque markers to measure regional myocardial geometry, MI was created by ligating the obtuse marginals of the circumflex artery. In the first study, pigs were randomized to MMPi (n=7; PD166793, 20 mg x kg(-1) x d(-1)) or MI only (n=7) at 5 days after MI, and measurements were performed at 2 weeks. Regional MI areas were equivalent at randomization and were increased in the MI-only group at 2 weeks after MI compared with the MMPi group. In the second study, pigs randomized to MMPi (n=9) or MI only (n=8) were serially followed up for 8 weeks. At 8 weeks after MI, LV end-diastolic dimension was lower with MMPi than in the MI-only group (4.7+/-0.1 versus 5.1+/-0.1 cm, P<0.05). Regional MI area was reduced with MMPi at 8 weeks after MI (1.3+/-0.1 versus 1.7+/-0.1 cm2, P<0.05). MMPi reduced ex vivo MMP proteolytic activity. In the MI region, membrane-type MMP levels were normalized and levels of the endogenous tissue inhibitor of MMPs (TIMP-1) were increased compared with normal levels with MMPi. These effects were not observed in the MI-only group.

CONCLUSIONS

MMPi attenuated the degree of post-MI LV dilation and expansion of the infarct during the late phase of MI healing. In addition, exogenous MMPi caused region-specific modulation of certain MMP and TIMP species.

Cardiorenal effects of adenosine subtype 1 (A1) receptor inhibition in an experimental model of heart failure

BACKGROUND

Elaboration of a number of bioactive substances, including adenosine, occurs in heart failure (HF). Adenosine, through the adenosine subtype 1 (A1) receptor, can reduce renal perfusion pressure and glomerular filtration rate and increase tubular sodium reabsorption, which can affect natriuresis and aquaresis. Accordingly, the present study examined the acute effects of selective A1 receptor blockade on hemodynamics and renal function in a model of HF.

STUDY DESIGN

HF was induced in adult pigs (n = 19) by chronic pacing (240 beats/min for 3 weeks). The pigs were then instrumented for hemodynamic and renal function measurements. After baseline measurements were taken, pigs received either A1 block [ 1 mg/kg BG9719 (1,3-dipropyl-8-[2(5,6-epoxynorbornyl)]xanthine; n = 9)] or infusion of vehicle (n = 10), and measurements were repeated at intervals for up to 2 hours. Normal controls (n = 7) were included for comparison.

RESULTS

Cardiac output remained unchanged between the A1 block and vehicle groups throughout the study. Pulmonary vascular resistance fell 38% from baseline at 10 minutes post-A1 block in the HF group (p < 0.05) with no change in the vehicle group. At 10 minutes post-A1 block, urine flow increased sixfold and sodium excretion increased over 10-fold (for both, p < 0.05) with no change in the vehicle group. At 10 minutes post-A1 block, creatinine clearance increased with no change in the vehicle group. At 10 minutes post-A1 block, plasma renin activity had increased over threefold (p <0.05), and it returned to baseline levels by 30 minutes post-A1 block.

CONCLUSIONS

The unique findings from this study were threefold. First, increased A1 receptor activation contributes to renal mediated fluid retention in HF. Second, selective A1 blockade can induce diuresis without hemodynamic compromise and with possible benefit to pulmonary resistance in a model of HF. A1 blockade transiently increased plasma renin activity with no change in hemodynamics. These unique results suggest that selective A1 blockade can be a useful adjunctive diuretic in the setting of HF.

Spontaneous Infarction of a Parathyroid Adenoma: Two Case Reports and Review of the Literature

The spontaneous infarction of a parathyroid adenoma is an uncommon event, although it has been previously described. Patients may present symptomatically or experience resolution of their hyperparathyroidism. As such the appropriate clinical management of these patients remains unclear. We present two cases of spontaneous infarction of parathyroid adenomas. The first presented with neck pain and dysphagia and experienced at least temporary resolution of her hyperparathyroidism. The second patient experienced a fall in his parathyroid hormone and calcium levels before neck exploration. Inf arcted parathyroid adenoma was diagnosed on pathologic evaluation of the surgical specimen. Inflammation surrounding the infarcted adenoma provided for a technically difficult operation. Although resolution of hyperparathyroidism has been described postinfarction, a regeneration of the parathyroid adenoma may occur. Therefore neck exploration and parathyroidectomy should still be considered. We propose a period of observation after diagnosis of spontaneous parathyroid adenoma infarction to avoid these acute inflammatory changes that have been described.

Spontaneous infarction of a parathyroid adenoma: two case reports and review of the literature

The spontaneous infarction of a parathyroid adenoma is an uncommon event, although it has been previously described. Patients may present symptomatically or experience resolution of their hyperparathyroidism. As such the appropriate clinical management of these patients remains unclear. We present two cases of spontaneous infarction of parathyroid adenomas. The first presented with neck pain and dysphagia and experienced at least temporary resolution of her hyperparathyroidism. The second patient experienced a fall in his parathyroid hormone and calcium levels before neck exploration. Infarcted parathyroid adenoma was diagnosed on pathologic evaluation of the surgical specimen. Inflammation surrounding the infarcted adenoma provided for a technically difficult operation. Although resolution of hyperparathyroidism has been described postinfarction, a regeneration of the parathyroid adenoma may occur. Therefore neck exploration and parathyroidectomy should still be considered. We propose a period of observation after diagnosis of spontaneous parathyroid adenoma infarction to avoid these acute inflammatory changes that have been described.

Effects of adenosine receptor subtype A1 on ventricular and renal function

The adenosine subtype 1 (A1) receptor, which may influence cardiac function and modulate renal function, may have particular relevance in congestive heart failure (CHF). However, the effects of A1 receptor inhibition in the setting of CHF are poorly defined. Systemic hemodynamics and indices of renal function were measured in pigs with pacing-induced CHF at 240 bpm for 3 weeks (n = 10) before and after A1 receptor blockade with 100 microg of BG9719 (1,3-dipropyl-8-[2-(5,6-epoxynorbornyl)]xanthene) or in CHF pigs after infusion of vehicle only (n = 10). Heart rate, mean aortic pressure, and left ventricular peak pressure increased following A1 blockade in the CHF group, consistent with an adenosine inhibitory effect. However, cardiac output and global measures of vascular resistance did not significantly change following A1 blockade. Urine output increased twofold and sodium clearance increased threefold following A1 blockade (p < 0.05). Creatinine clearance increased following A1 blockade (127 +/- 17 vs. 62 +/- 7 ml/min, p < 0.05). Selective A1 receptor blockade improved glomerular filtration rate and induced a natriuresis and diuresis in a model of CHF without adverse effects on cardiac function. These unique results suggest that renal A1 receptor activation may contribute to the reduced renal function associated with CHF.

Surgical options for the treatment of heart failure

This article will examine the role of specific surgical interventions for congestive heart failure (CHF). The most definitive surgical option for severe end-stage heart failure is cardiac transplantation. In general, patients considered for heart transplant should have severe heart disease despite all other therapies with a high risk of death within 1 year. Noncardiac conditions that would by themselves shorten life expectancy or increase the risks of rejection, infection, or other fatal complication, should not be present. However, in light of the limited donor pool, complications associated with long-term immunosuppressive therapy, and the ever-increasing number of CHF patients, the role of cardiac transplantation for CHF will continue to be limited. The conduct of and evaluation for cardiac transplantation has been well described previously and therefore will not be evaluated in this review (1); however, there has been recent progress in the genetic modification of animal organs for potential use in transplantation (xenografts) (2). If these developments come to fruition, then cardiac transplantation/organ replacement may become a surgical option for a much greater number of CHF patients. One alternative approach to complete cardiac transplantation is the surgical placement of transformed cells into the diseased myocardium, briefly discussed under "Future Directions." This article will examine surgical options that are currently being used for CHF patients, surgical modalities that are currently under clinical evaluation, and finally, potential future therapies with respect to surgical options for heart failure.

Predicting reading ability in first grade children

A screening test for early measurement of various aspects of reading ability was developed, utilizing findings from a number of previous researchers. The test was administered to two first grade classes ( n = 44), and correlated at significant levels with both teacher estimates and objective measures of reading ability. Findings suggest that a group-screening procedure may be effective in predicting reading disability and may further help identify the child's areas of weakness and so point to appropriate remedial procedures.