Comments ``Rapid evaluation of integer-order Bessel functions usingan FFT algorithm' [and reply]

The commenter disagrees with a statement by J. Nachamkin and D.C. Hoffman (see ibid., vol.33, no.6, p.33-5, Dec. 1991) that complicated procedures are needed to find the initial terms in the recursion relation when backward-recursion techniques are used, and points out that the initial terms required to start backward recursion need not be calculated at J. Nachamkin agrees that in many cases using recursions is better than all the other methods     

Adaptive multiwavelet initialization

The multiwavelet concept uses a set of scaling functions and a set of wavelets to generate an orthogonal multichannel multiresolution pyramid decomposition for finite energy signals. The multiple scaling functions extract the lowpass information of the input data set, and the multiwavelets extract the bandpass information. When the lowpass filters associated with the scaling functions are cascaded, a multiresolution pyramid decomposition/reconstruction system is formed with each pyramid convolution operator having several inputs and several outputs. However, there is only one data set available to initialize this process. This paper addresses the question of how to best modify the data set using prefilters so that its decomposition contains the most useful information for the chosen application. The “best” prefilters are determined by the minimization of the energy of preselected decomposition components. The resulting decomposition is, therefore, signal adaptive, and under appropriate conditions, perfect reconstruction of the input data set can be achieved with a proper postfiltering. The detailed discussions in the paper are focussed on the two-wavelet and two-scaling function case; the general multiwavelet case is addressed at the end of the paper. A compression example is provided to demonstrate the performance of the optimally initialized multiwavelet method and to compare it with a single wavelet method and another multiwavelet initialization method proposed by other authors     

Age-related differences in the temporal and spatial regulation of matrix metalloproteinases (MMPs) in normal skin and acute cutaneous wounds of healthy humans

Despite the association of increasing age with chronic wound-healing disorders and an impaired rate of healing of acute cutaneous wounds, the role of matrix metalloproteinases (MMPs) is unknown. To determine the spatial and temporal patterns and activities of MMP-1, -2, -3 and -9, 132 healthy humans aged between 19 and 96 years underwent 4-mm punch biopsies followed by wound excision between day 1 and day 180 post-wounding. Wounds showed an age-related increase in MMP-2 and MMP-9 immunostaining from day 3; this was associated with degradation of gelatin as shown by zymograms and with increased proteinase activity as shown by azocoll assays. Distinct spatial localisations for each MMP were observed: MMP-2 was found in epidermal structures; MMP-9 was observed in inflammatory cells up to day 21; MMP-1 was localised to keratinocytes at the wound margin. Normal old skin showed pro-MMP-2 bands on zymography and increased MMP-2 immunostaining. These results indicate that: (1) intrinsic ageing is associated with the up-regulation of MMPs previously associated with chronic wound healing; (2) wound-tissue proteinases are essentially active up to day 21 postwounding; and (3) intrinsic ageing may predispose to tissue breakdown disorders because of MMP-2 up-regulation in normal skin.     

Octreotide in hyperinsulinism

In a limited number of case reports in infants, octreotide raised the blood glucose concentrations and decreased glucose requirements sufficiently to avoid pancreatectomy. This response occurs in the presence of frequent feedings and diazoxide therapy, and lasts from 1 month to greater than 5 years. As expected, octreotide reduces growth indices such as growth factors and growth rate in short-term assessment. However, an insufficient sample size, a lack of follow-up, and poor study design provide inconclusive data. Among the few case reports in adults with benign or malignant insulinoma, octreotide can significantly raise blood glucose concentrations. In long-term follow-up, octreotide has alleviated or reduced the frequency of hypoglycemic episodes for periods of 5 months to 2.5 years. Octreotide was administered subcutaneously in regimens of 100-1500 micrograms in three to four divided doses or as a continuous infusion. Continuous subcutaneous infusion may be attempted in patients intolerant to intermittent administration. Octreotide may worsen existing hypoglycemia as result of suppressing glucagon and growth hormone in the presence of unresponsive pancreatic hyperinsulinism. While the long-term effects of growth remain undetermined, current findings suggest octreotide may provide a reasonable addition or alternative to diazoxide in controlling symptoms of congenital hyperinsulinism. Octreotide may be useful in management of hypoglycemic symptoms in adult patients requiring medical treatment for insulinoma who are refractory or intolerant of diazoxide. Additional long-term studies are needed to address the cost effectiveness of octreotide therapy, identify patients most likely to respond, and determine the impact of octreotide on height.     

Gastric myoelectrical activity, gastric emptying and correlations with dyspepsia symptoms in patients with gastroesophageal reflux

BACKGROUND: Delayed gastric emptying is a mechanism that contributes to the pathogenesis of gastroesophageal reflux. Electrogastrogram changes, gastric emptying rates, and Helicobacter pylori status were investigated, and a correlation was sought with dyspepsia symptoms in gastroesophageal reflux disease patients. METHODS: Fifty patients (27 females; mean age 43) with gastroesophageal reflux were studied. Electrogastrographic recordings were obtained 30 minutes before and simultaneously with a 2-hour radionuclide gastric-emptying test using an isotope-labeled solid meal. Symptoms of nausea, abdominal bloating, abdominal pain, and early satiety were graded from 0 to 5. RESULTS: Thirty-six percent of patients had delayed gastric eliminating. Thirty-eight percent (19/50) patients had abnormal electrogastrograms, and 11 of these 19 also had delayed gastric emptying. There was a significant difference in the electrogastrographic parameter of postprandial power change in patients with delayed versus normal gastric emptying (0.20 +/- 0.8 dB vs 3.17 +/- 0.8 dB, p < 0.05). In patients with an abnormal electrogastrogram, the mean symptom score was significantly higher than in patients with a normal electrogastrogram (2.18 +/- 0.26 vs 1.35 +/- 0.16, p < 0.05). Twenty-one percent (7/33) of patients were positive (+) for Helicobacter pylori overall, but this did not seem to affect electrogastrogram and gastric emptying findings. CONCLUSIONS: Fifty-two percent of gastroesophageal reflux disease patients have gastric motor or myoelectrical abnormalities that contribute to the pathogenesis of this entity and also help explain the high prevalence of dyspepsia in the clinical presentation of gastroesophageal reflux disease.     

Mathematics self-efficacy and mathematics performances: The need for specificity of assessment.

In this study, 391 students were asked to provide 3 types of mathematics self-efficacy judgments: confidence to solve mathematics problems, confidence to succeed in math-related courses, and confidence to perform math-related tasks. Criterial tasks were solution of math problems and choice of math-related majors. As hypothesized, students' reported confidence to solve the problems they were later asked to solve was a more powerful predictor of that performance than was either their confidence to perform math-related tasks or to succeed in math-related courses. Similarly, confidence to succeed in math-related courses was a stronger predictor of choice of math-related majors than was either confidence to solve problems or to perform math-related tasks. Results support A. Bandura's (1986) contention that, because judgments of self-efficacy are task specific, measures of self-efficacy should be tailored to the criterial task being assessed and the domain of functioning being analyzed to increase prediction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunohistochemical localization of somatostatin receptor SST2A in the rat pancreas

Somatostatin (SRIF) acts on specific membrane receptors to inhibit exocrine and endocrine pancreatic functions. Five SRIF receptor genes have been cloned, producing six receptor proteins (sst-s). We used a recently developed antibody to localize the sst2A splice variant in the rat pancreas. Western blots identified the sst2A receptor as an 90 kDa glycosylated protein in pancreatic tissue. In tyramide-amplified immunostainings all acinar cells, and the glucagon and pancreatic polypeptide immunoreactive cells (A and PP, respectively) were intensely labeled for sst2A, while no signal was detected in SRIF producing (D) cells. A very few insulin immunoreactive (B) cells were also labeled for sst2A, but the signal in these cells was lower than in exocrine, A or PP cells. Absorption of the sst2A antibody with the receptor peptide abolished specific staining in both immunoblots and tissue sections (negative control). These studies are the first to localize any SRIF receptor subtype in the rat pancreas. The specific localization of sst2A receptor in acinar, A and PP cells if confirmed in humans, would suggest that subtype specific analogs will be useful for the therapeutic regulation of exocrine and/or endocrine pancreatic secretion.