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Biomedical subjects

S Miller

Publications and source records attributed to S Miller.

At least 271 records · Page 15Linked to original sources
PubMed1995

Foveal electroretinograms and choroidal perfusion characteristics in fellow eyes of patients with unilateral neovascular age-related macular degeneration.

AIMS/BACKGROUND: A prolonged choroidal filling phase on fluorescein angiography has been reported to be a common finding and associated with visual function abnormalities in patients with age-related macular degeneration (AMD). This investigation was carried out to determine whether this perfusion defect was related to the slowing of foveal cone electroretinogram (ERG) implicit time seen in patients with AMD. METHODS: Fluorescein angiograms and foveal cone ERGs were evaluated in the fellow eyes of 67 patients with unilateral neovascular AMD. RESULTS: Twenty eight (42%) of the eyes had a choroidal perfusion defect. ERG implicit times averaged 1 ms slower (p = 0.0167) and were more likely to be delayed (p = 0.0078) in eyes with abnormal choroidal perfusion than in eyes with normal choroidal filling; significant relations were found also after controlling for age. ERG implicit time was also inversely related to ETDRS visual acuity and positively related to the extent of macular drusen; and the latter showed a borderline significant tendency to be more prevalent in eyes with prolonged choroidal perfusion. However, an association of a delayed ERG implicit time with prolonged choroidal filling remained after controlling for age, acuity, and the extent of drusen. CONCLUSION: These findings further establish prolonged choroidal perfusion as a common finding in AMD and link it to retinal malfunction.

Aged↗
PubMed1995

Chest physiotherapy in cystic fibrosis: a comparative study of autogenic drainage and the active cycle of breathing techniques with postural drainage.

BACKGROUND--Autogenic drainage has been suggested as an alternative method of chest physiotherapy in patients with cystic fibrosis. In this study autogenic drainage was compared with the active cycle of breathing techniques (ACBT) together with postural drainage. METHODS--Eighteen patients with cystic fibrosis took part in a randomised two-day crossover trial. There were two sessions of one method of physiotherapy on each day, either autogenic drainage or ACBT. The study days were one week apart. On each day the patients were monitored for six hours. Mucus movement was quantified by a radioaerosol technique. Airway clearance was studied qualitatively using xenon-133 scintigraphic studies at the start and end of each day. Expectorated sputum was collected during and for one hour after each session of physiotherapy. Pulmonary functions tests were performed before and after each session. Oxygen saturation (SaO2) and heart rate were measured before, during, and after each session. RESULTS--Autogenic drainage cleared mucus from the lungs faster than ACBT over the whole day. Both methods improved ventilation, as assessed by the xenon-133 ventilation studies. No overall differences were found in the pulmonary function test results, but more patients had an improved forced expiratory flow from 25% to 75% with autogenic drainage, while more showed an improved forced vital capacity with ACBT. No differences were found in sputum weight and heart rate, nor in mean SaO2 over the series, but four patients desaturated during ACBT. CONCLUSIONS--Autogenic drainage was found to be as good as ACBT at clearing mucus in patients with cystic fibrosis and is therefore an effective method of home physiotherapy. Patients with cystic fibrosis should be assessed as to which method suits them best.

Adolescent↗
PubMed1995

AIDS-related lymphoma: radiologic features in pediatric patients.

PURPOSE: To determine the clinical, pathologic, and radiologic features in pediatric patients with acquired immunodeficiency syndrome (AIDS)-related lymphoma and to compare these features with those in adult patients with AIDS-related lymphoma. MATERIALS AND METHODS: Clinical and radiologic findings were retrospectively reviewed in nine children (aged 1-15 years) with AIDS-related lymphoma. All patients had neoplastic changes that were not consistent with hyperplastic lymphoid tissue. The children underwent ultrasonography, computed tomography, magnetic resonance imaging, and plain radiography. RESULTS: Sites of involvement by malignant non-Hodgkin lymphoma at diagnosis were the liver (n = 7), spleen (n = 5), kidney (n = 4), central nervous system (n = 2), and testis and bone (n = 1). Symptoms included seizures, respiratory distress, testicular swelling, and increased abdominal girth. CONCLUSION: Children with AIDS-related lymphoma have symptoms distinct from those found in adults, but clinical, radiologic, and pathologic findings show that almost any anatomic site in these children can be involved.

Adolescent↗
PubMed1995

Ultrastructural effects of estradiol and 5 alpha-androstane-3 alpha, 17 beta-diol on neurons within the ventromedial nucleus of the hypothalamus.

The metabolite of dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-Diol), is a potent inhibitor of estrogen-induced gonadotropin and prolactin secretion and lordosis behavior in the female rat. This study examined whether 3 alpha-Diol can counteract the ultrastructural changes which are known to occur in the ventromedial nucleus (VMN) of the hypothalamus following estrogen treatment. Ovariectomized rats were treated with estradiol (E2; n = 7), 3 alpha-Diol (n = 5), E2 and 3 alpha-Diol (n = 6), or received control (n = 6) treatments. E2 was administered in subcutaneous capsules for two discontinuous 2-hour periods separated by 5 h, a 'pulsed' treatment regimen known to mimic the timing of endogenous E2 action and to influence neuronal ultrastructure in the VMN. Animals given 3 alpha-Diol received subcutaneous injections (6 mg/kg) 3 h prior to each implantation of E2 or empty capsules. Control animals received vehicle 3 h prior to implantation of blank capsules. Animals were perfused 24 h after initial hormone treatment and neurons from the ventrolateral portion of the VMN were examined using electron microscopy. Separately, both E2 and 3 alpha-Diol treatment increased somal and nuclear size, altered somal and nuclear shape, and increased the numbers of lysosomes present in the cytoplasm above control levels. E2 treatment resulted in increased stacking of the rough endoplasmic reticulum while 3 alpha-Diol treatment resulted in an unusual plexiform rough endoplasmic reticulum distribution. In contrast, combined treatment with E2 and 3 alpha-Diol resulted in cells which were similar to ovariectomized control cells on these measures. All steroid treatments decreased the amount of heterochromatin present within the nucleus compared to that seen in controls. Thus, 3 alpha-Diol influences the ultrastructural characteristics of neurons within the VMN in a manner somewhat though not altogether similar to E2. However, 3 alpha-Diol given in combination with E2 counteracts or prevents the actions of E2 within these same neurons.

Androstane-3,17-diol↗
PubMed1995

High-intensity focused ultrasound (HIFU) in the treatment of benign prostatic hyperplasia (BPH).

Transurethral resection of the prostate (TURP) and open adenectomy are regarded the golden standard in the management of patients with symptomatic benign prostatic hyperplasia (BPH). Various alternative treatment forms (microwaves, laser, radiofrequency, focused ultrasound) have been introduced recently. They all aim at reduction of morbidity related to TURP keeping a comparable efficacy at the same time. Since December 1992, 50 patients with BPH have been treated by high intensity focused ultrasound (HIFU-P) at our department. Six weeks following HIFU-P mean Qmax improved from 5.7 ml/s to 11.6 ml/s. Post voiding residual volume (RV) dropped from 215 ml to 100 ml, the International Prostate Symptom Score (IPSS) from 19.8 to 9.9. Both, IPSS and RV further improved during the following weeks. Follow-up data one year after treatment demonstrate that results remained stable in the majority of patients. Urinary tract infections were observed in 3 patients, macrohematospermia in all and macrohematuria (caused by the suprapubic catheter) requiring blood transfusion in 1 patient.

Aged↗
PubMed1995

[High energy focused ultrasound in treatment of benign prostatic hyperplasia].

Transurethral resection of the prostate (TURP) and open adenectomy are regarded the "golden standard" in the treatment of benign prostate hyperplasia (BPH). Various alternative treatment forms (microwaves, laser, radio frequency, focused ultrasound) have been introduced recently. They are all aimed at reducing the morbidity related to TURP while achieving comparable efficacy at the same time. Since December 1992, 35 patients with BPH have been treated with high-intensity focused ultrasound (HIFU-P) in our department. By 6 weeks after HIFU-P, mean Qmax had improved from 6.5 ml/s to 12.1 ml/s. Residual volume dropped from 207 ml to 95 ml, IPSS from 20.1 to 9.7. Both subjective as well as objective improvements remained stable after 3 and 6 months. Urinary tract infections were observed in 3 patients, macrohemato-spermia in all, and macrohematuria (caused by the suprapubic catheter) requiring blood transfusion in 1 patient.

Aged↗
PubMed1995

Growth factor upregulation of a phosphoinositide-coupled metabotropic glutamate receptor in cortical astrocytes.

CNS function depends on a capacity for plasticity during development, following injury, and in response to changing environmental conditions. Functional alterations in signal transduction pathways and in neurotransmitter receptor expression are possible mechanisms for the expression of such plasticity. In the present report, we demonstrate that exposure of astrocytes to specific growth factors alters both the functional activity and the protein levels of a specific glutamate receptor. Exposure of astrocytes to basic fibroblast growth factor, epidermal growth factor, or transforming growth factor-alpha produced marked increases in the ability of metabotropic glutamate receptor (mGluR) agonists to stimulate phosphoinositide hydrolysis. Using Western immunoblotting, we demonstrate that an increase in the levels of one of the phosphoinositide-coupled mGluR subtypes, mGluR5, accompanies the increased ability of mGluR agonists to stimulate phosphoinositide hydrolysis. In contrast, another phosphoinositide-coupled subtype of this receptor family, mGluR1 alpha, was not present at detectable levels in these cultures. The enhanced stimulation of phosphoinositide hydrolysis showed little sensitivity to pertussis toxin, and appeared to be selective to mGluR agonists, as there was not a similar increase in the ability of norepinephrine or carbachol to stimulate phosphoinositide hydrolysis. These findings demonstrate that expression of mGluRs in astrocytes is plastic, and indicate a novel pathway through which specific growth factors may selectively modulate neurotransmitter action.

Animals↗
PubMed1995

More pearls.

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Alcoholism↗
PubMed1995

Tungiasis.

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Adult↗
PubMed1995

Intra-oral remineralization of enamel with a MFP/DCPD and MFP/silica dentifrice using surface microhardness.

The present study was undertaken to ascertain the effect of dicalcium phosphate dihydrate (DCPD) abrasive in a dentifrice on the remineralizaton of enamel using a surface microhardness technique. The method of assessing enamel remineralization via surface microhardness (SMH) was validated in a randomized, crossover, double-blind, intra-oral remineralization study conducted with 12 healthy adults. Enamel demineralization was achieved in vitro by covering bovine enamel blocks with exogenous oral bacteria, S. Mutans 1600 Ingbritt, containing glucan which was then exposed to sucrose. In the intra-oral treatment phase, subjects were fitted with oral maxillary palatal retainers, each holding four demineralized enamel blocks. Subjects brushed their teeth for 30 seconds with a test dentifrice, swished for an additional 60 seconds, rinsed with water and then retained the blocks intra-orally for 4 hours. Percent mineral recovery for each enamel block was calculated as the ratio of the changes in enamel microhardness due to treatment (remin) and sucrose challenge (demin). Treatments included DCPD-based dentifrices containing 0, 250 and 1000 ppm fluoride (F) from sodium monofluorophosphate (MFP). Using SMH, respective mean percent mineral recoveries of 5.7, 18.7 and 41.4% were obtained. All ADA criteria for model validation were fulfilled. This same model was then used to compare the remineralization effects of a silica placebo, DCPD placebo, 1000 ppm F MFP/silica and 1000 ppm F MFP/DCPD dentifrice. Mean percent mineral recoveries of -0.9, 24.1, 30.2 and 55.7% were obtained, respectively. The MFP/DCPD dentifrice was superior to MFP/silica (<0.01) with use of the MFP/DCPD dentifrice when compared to MFP/silica or the silica placebo. These results indicate that more active calcium and a higher degree of saturation (DS(EN)) with respect to enamel exists for an extended period of time after use of a MFP/DCPD dentifrice. Since an elevation in DS(EN) is considered a major parameter controlling the extent of enamel remineralization, this finding may partly explain the superior remineralization of enamel observed with the MFP/DCPD dentifrice. The significant increases in calcium activity and intra-oral enamel remineralization by the DCPD-based dentifrice are consistent with earlier findings that a DCPD abrasive provides added benefit for enamel remineralization.

Adolescent↗
PubMed1994

Pravastatin reduces serum cholesterol and low density lipoprotein concentrations following pancreas transplantation.

Hyperlipidemia is a significant risk factor for atherosclerotic vascular disease. We have shown previously that pancreas transplantation (PTX) improves but does not normalize lipids in most PTX recipients. We studied whether pravastatin was effective in treating 10 patients with elevated low density lipoprotein (LDL)-cholesterol (LDL-C) following PTX. Seven men and 3 women were studied. Six received combined kidney-pancreas transplantations, while 4 received PTX alone. Age at time of PTX was 37.2 +/- 2.2 years (mean +/- SEM), and 4 had established coronary artery disease before PTX. Mean cholesterol (C), LDL-C, triglycerides (TG), and high density lipoprotein (HDL)-cholesterol (HDL-C) were 236 +/- 12, 142 +/- 6, 222 +/- 50, and 49 +/- 4 mg/dl before PTX. The LDL to HDL ratio was 3.0 +/- 0.3. After PTX, excluding the first 45 days, mean C, LDL-C, and HDL-C increased to 278 +/- 10, 178 +/- 7, and 63 +/- 6 mg/dl (all P < or = 0.05), respectively. TG, LDL to HDL ratio, and weight were unchanged. Pravastatin (11.7 +/- 0.8 mg/day, mean +/- SEM) was initiated 250 +/- 53 days after PTX. During therapy, C and LDL-C decreased on average to 231 +/- 10 and 134 +/- 8 mg/dl, respectively (both P < 0.01), while HDL did not change. The decreases in C and LDL-C were unexplained by a decrease in weight, cyclosporine dose or concentration, or increase in serum creatinine. However, prednisone dose decreased over the same interval, so a contribution from this variable cannot be excluded. No evidence of toxicity was identified during therapy. This is one of the first reports demonstrating that pravastatin is a safe and effective treatment for elevated C and LDL-C in patients following PTX. However, pravastatin did not increase HDL or decrease TG, as observed in the nontransplantation setting. Whether pravastatin or any hypolipidemia therapy can prevent cardiovascular events or mortality following PTX remains to be established.

Adult↗
PubMed1994

Pharmacological dissociation of glutamatergic metabotropic signal transduction pathways in cortical astrocytes.

Using cultured cortical astrocytes we demonstrate differential activation of metabotropic signal transduction pathways with 1-aminocyclopentane-trans-1S3R-dicarboxylic acid (1S3R-ACPD) and the glutamate transport inhibitor trans-2,4-pyrrolidine dicarboxylic acid (trans-2,4-PDC). Phosphoinositide hydrolysis was more potently stimulated by 1S3R-ACPD than by L-trans-2,4-PDC; however, L-trans-2,4-PDC was far more efficacious than 1S3R-ACPD at inhibiting cyclic AMP accumulation. The metabotropic receptor antagonist (+)-alpha-methyl-4-carboxyphenylglycine ((+)-MCPG) inhibited 1S3R-ACPD stimulation of phosphoinositide hydrolysis but not its ability to inhibit cyclic AMP accumulation thereby demonstrating a means to pharmacologically dissociate these two metabotropic signal transduction pathways in astrocytes. (+)-MCPG produced similar antagonism of the metabotropic agonist properties of L-trans-2,4-PDC. The metabotropic effects of L-trans-2,4-PDC could not be reduced with enzymatic treatment of the cultures to remove extracellular glutamate, suggesting that these effects are not secondary to the ability of this compound to inhibit glutamate uptake. Taken together the findings indicate the presence of multiple glutamatergic signal transduction pathways in astrocytes and suggest a similarity in the pharmacophores for metabotropic receptors and glutamate transporters.

Animals↗
PubMed1994

Genetic organization of the region upstream from the Campylobacter jejuni flagellar gene flhA.

Campylobacter jejuni (Cj) is a Gram-bacterium that causes a diarrheal disease in humans. A Cj homolog of the LcrD/FlhA family of proteins was recently described [Miller et al., Infect. Immun. 61 (1993) 2930-2936]. This family includes proteins that are involved in flagellar biogenesis, such as the Cj FlhA protein, but also includes proteins found in invasive pathogens, such as the Yersinia pestis LcrD protein, that play a role in the regulation and/or secretion of virulence-related proteins. Hybridization studies indicated that both the flhA gene and upstream DNA are present in several bacterial species closely related to Cj, including C. fetus, C. lari, C. upsaliensis and C. hyointestinalis. The presence of a second flhA/lcrD homolog was not detected in Cj, indicating that a a separate homolog involved in secretion of virulence proteins may not be present. The 4-kb region immediately upstream from Cj flhA was analyzed. Three open reading frames (ORFs) were found: a 408-nucleotide (nt) gene encoding a homolog of proteins present in Escherichia coli and Desulfovibrio vulgaris, but of unknown function, a 266-nt rpsO gene and a 2823-nt gene encoding a homolog of the Bacillus subtilis SpoIIIE protein. The Cj SpoIIIE homolog had 53% similar or identical amino acids when compared to the B. subtilis protein, and like the B. subtilis protein contained a nt-binding domain and potential transmembrane (TM) regions. All three ORFs were expressed in E. coli minicells, apparently from their own promoters.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Crystal structure of P22 tailspike protein: interdigitated subunits in a thermostable trimer.

The tailspike protein (TSP) of Salmonella typhimurium phage P22 is a part of the apparatus by which the phage attaches to the bacterial host and hydrolyzes the O antigen. It has served as a model system for genetic and biochemical analysis of protein folding. The x-ray structure of a shortened TSP (residues 109 to 666) was determined to a 2.0 angstrom resolution. Each subunit of the homotrimer contains a large parallel beta helix. The interdigitation of the polypeptide chains at the carboxyl termini is important to protrimer formation in the folding pathway and to thermostability of the mature protein.

Bacteriophage P22↗
PubMed1994

Managing the mind.

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Health Care Reform↗