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P Allen

Publications and source records attributed to P Allen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Prognostic biomarker study in pathologically staged N1 non-small cell lung cancer.

PURPOSE: The prognostic influence of 6 biomarkers correlated to histologic subtypes of non-small cell lung cancer (NSCLC) on loco-regional control, overall survival, disease-free survival (DFS), and distant disease control (DDC) rates, all measured at 5 years, were examined. MATERIALS & METHODS: Cell blocks from the primary tumors of 137 patients with pathologically staged N1 NSCLC at MDACC were analyzed by 6-biomarker status correlated to histological subtypes and their outcomes. RESULTS: The ranges of biomarker values were as follows: apoptotic index, 0.2-2.8%; mitotic index, 0-1.8%; the proportion of cells in S+G2M, 3-36%; p53 status, 0-100%; Ki-67, 0-9.3%; DNA index, 1.0-2.74. Subtypes of 137 cases from the postoperative pathology specimen showed that 74 patients had squamous carcinoma and 63 patients had adenocarcinoma. Mean and median lengths of follow-up were 4.21 years and 2.43 years, respectively. Patients with squamous cell carcinoma (SCC) had a better 5-year survival (p = 0.006), DFS (p = 0.002), and distant metastasis control (p = 0.002) than patients with adenocarcinoma (AC). Among patients with AC, the DNA index was a significant predictor of 5-year DFS (p = 0.02), DDC rate (p = 0.04), and local-regional control (p < 0.05). Higher apoptosis (p = 0.03) and mitosis indices (p = 0.03) were also univariate predictors of increased distant disease among patients with AC. Multivariate analysis of patients with AC revealed that the DNA index and Ki-67 were the only significant independent predictors of distant metastasis (p < 0.04 and p < 0.02, respectively) and DFS (p < 0.04 for both). Among patients with SCC, univariate analysis showed that S+G2M proportion (p < 0.05) and Ki-67 levels (p < 0.02) were significant predictors for local-regional control; for SC, multivariate analysis showed that only mitosis was a significant predictor in this case for overall survival (p < 0.04). CONCLUSION: Spontaneous apoptotic index and Ki-67 were significantly higher in SC than in AC. Patients with SC had less distant metastasis better DFS and overall survival than those with AC. Multivariate analysis revealed that DNA index and Ki-67 status were significant predictors for DDC and DFS in patients with AC, but only mitotic index was a significant predictor of overall survival for patients with SCC.

Adenocarcinoma↗
PubMed1998

Effects of perindopril on renal histomorphometry in diabetic subjects with microalbuminuria: a 3-year placebo-controlled biopsy study.

We conducted a 3-year randomized placebo-controlled double-blind study to determine the effects of the angiotensin-converting enzyme (ACE) inhibitor perindopril (PE) on the progress of renal function and histology in subjects with diabetes and microalbuminuria. Forty non-insulin-dependent (NIDDM) and insulin-dependent (IDDM) diabetic subjects, either normotensive or hypertensive, were randomly assigned to receive PE (n = 20) or placebo (n = 20). A percutaneous renal biopsy was performed initially in all patients and repeated in 29 patients after 3 years. The mean glomerular volume, glomerular basement membrane (GBM) thickness, interstitial fibrosis, sclerosed glomeruli, and volume fraction of capillary lumina were measured histomorphometrically. Before treatment, both groups had similar clinical characteristics, blood pressure, glycosylated hemoglobin (Hb), albumin excretion rate, glomerular filtration rate (GFR), serum creatinine, and renal structural damage. Blood pressure was well controlled in both groups. After 3 years' therapy, there was no significant change in renal function and albuminuria in the PE or placebo groups. The increase in GBM thickness in nine paired biopsies was significantly less in PE-treated subjects (P = .0275). Interstitial fibrosis tended to increase less in the PE group, although this did not reach statistical significance. This study indicates that long-term therapy with PE may decrease or delay the progression of structural glomerular damage in microalbuminuric diabetic subjects.

Adult↗
PubMed1998

The ophthalmic registered nurse's responsibility to the adult patient with low vision.

A key goal in the care of adult patients with low vision is to help them focus on their visual abilities rather than their disabilities. This article presents information that every ophthalmic nurse can use to teach patients with low vision some practical ways to change their personal environment to enhance visibility and safety. There are also some myths and misunderstandings about low vision that the nurse can dispel. Before referring patients to low-vision specialty clinics or organizations, every ophthalmic nurse can begin the visual rehabilitation for patients with low vision.

Activities of Daily Living↗
PubMed1998

Physical, chemical, and histologic changes in dentin caries lesions of primary teeth induced by regular use of polyol chewing gums.

A previous clinical trial showed that long-term use of saliva-stimulating polyol (xylitol and sorbitol) chewing gums was associated with arrest of dental caries in young subjects. After a 20-22-month intervention (when the subjects were 8 years old), a total of 23 primary teeth with extensive dentin caries lesions whose surface in clinical examination was found to be totally rehardened (remineralized) could be removed because the teeth were near their physiologic exfoliation time. These teeth were subjected to histologic, microhardness, and electron microscopic tests. The majority of the specimens had been remineralized from the surface by a non-cellular-mediated process within the remaining collapsed, organic extracellular matrix associated with the remaining dentinal surface. Many of the underlying dentinal tubules were filled with a matrix that had been subsequently mineralized. Dental microanalyses showed that the topmost (outer) 20-microm-thick rehardened layer of the lesions exhibited the highest Ca:P ratio, which leveled off at a depth of approximately 150 microm. The rehardened surface layer (normally <0.1 mm in thickness) was significantly (P < 0.001) harder than sound dentin and nearly as hard as sound enamel. Although the main source of the mineral present in the rehardened layer was most likely of salivary origin, some extracellular remineralization was probably mediated by odontoblasts. The results complete the dinical diagnoses of the original trial and suggest that regular use of polyol chewing gums may induce changes in dentin caries lesions, which in histologic and physiochemical studies show typical characteristics of rehardening and mineralization.

Calcium↗
PubMed1998

Low versus high prevalence of AIDS: effect on nursing students' attitudes and knowledge.

The purpose of this study was to compare AIDS knowledge and attitudes of baccalaureate nursing students living in a state with a high prevalence of AIDS and those who resided in a state with a low prevalence of AIDS. Students from the high-prevalence state had significantly higher AIDS knowledge scores than did students from the low-prevalence state. However, overall, respondents from the low-prevalence state viewed the person living with AIDS with more accepting attitudes than did the respondents from the high-prevalence state. Students in the high-prevalence state interacted with persons living with AIDS (PLWA) primarily through professional contact. In contrast, students in the low-prevalence state identified both personal and professional contact with PLWA as their most significant interactions. Personal experience of nursing students appears to be a key to decreasing stigmatization of PLWA.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Nutrition support for patients in long-term acute care and subacute care facilities.

Long-term acute care and subacute care facilities (also transitional care facilities) have evolved from the need to decrease costs associated with acute care in the hospital. As the length of stay in many medical centers has been reduced, patients are admitted to transitional care facilities to continue recovery and rehabilitation. Rehabilitation and recovery can be enhanced with the provision of optimal medical nutrition therapy. Nutrition screening is essential in identifying patients who are at risk of malnutrition or are malnourished. Nutrition assessment verifies the risk or presence of malnutrition followed by the development, implementation, and monitoring of nutrition intervention. Nutrition screening and intervention promote recovery from illness, minimize morbidity and mortality, and enhance quality of life. The goals of nutrition support are to prevent starvation-associated malnutrition, preserve lean tissue mass, support metabolic functions, and improve clinical outcomes. Oral nutrition is the preferred method of nourishment; however, specialized nutrition support is considered for patients unable to meet their nutrient requirements adequately. Enteral nutrition support is recommended when providing nutrition support however, parenteral nutrition support is used when the gastrointestinal tract can not be safely used. With appropriate intention, administration, and monitoring, nutrition support can be safely administered.

Acute Disease↗
PubMed1998

The role of level, spectral, and temporal cues in children's detection of masked signals.

Preschool-aged children and adults were asked to detect masked signals in four conditions that evaluated the role of level, spectral, and temporal cues on performance. Psychometric functions fitted to percent correct data at several signal-to-noise ratios showed higher thresholds and shallower slopes for the children in all conditions. Performance was similar in fixed and roving level conditions for both age groups suggesting use of level-invariant cues. When the signal was moved to the spectral edge of the masker the performance of the adults improved but that of the children did not. This suggested that children did not benefit from the additional cues provided by the off-center signal. Children's performance worsened when the signal was a narrow-band noise rather than a pure tone but the adults' did not, suggesting children's reliance on temporal changes in the masker with the introduction of the signal. Analyses of the stimuli suggested that the children's thresholds corresponded to signal-to-noise ratios at which multiple cues were present at magnitudes that were great enough to be discriminable.

Adult↗
PubMed1998

Corneal abrasions.

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Corneal Injuries↗
PubMed1997

Fluvastatin.

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Anticholesteremic Agents↗
PubMed1997

Single-stranded RNA recognition by the bacteriophage T4 translational repressor, regA.

The T4 protein, RegA, is a translational repressor that blocks ribosome binding to multiple T4 messages by interacting with the mRNAs near their respective AUG start codons. Other than the AUG, there are no obvious similarities between the affected mRNAs. High affinity RNA ligands to RegA were isolated using SELEX (systematic evolution of ligands by exponential enrichment). The selected RNAs exhibited the consensus sequence 5'-AAAAUUGUUAUGUAA-3'. The AUG was invariant, suggesting that it is the primary effector of binding specificity. The UU immediately 5' to the AUG and the upstream poly(A) tract were highly conserved among the selected RNAs. Boundary and footprinting experiments are consistent with the consensus sequence defining the RegA-binding site. Interestingly, chemical modification and nuclease digestion data indicate that the RNA-binding site is single-stranded, as if RegA discriminates between targets based on their primary sequence, not their secondary structure. Minor variations from the consensus at positions other than the universally conserved AUG have little effect on RegA binding, but accumulation of mutations has a profound effect on the interaction. Comparison of the in vivo targets for RegA to the SELEX-generated consensus suggests a repression pattern whereby the translation of individual messages is sequentially halted until the least similarly affected message, the regA gene itself, is repressed.

Bacteriophage T4↗
PubMed1997

Multidimensional scaling of complex sounds by school-aged children and adults.

A paired-comparisons procedure was used to evaluate the processing of complex, nonspeech sounds by 7- and 10-year-old children and adults. Stimuli were brief duration and included pure tones, harmonic complexes, and bands of noise. From their similarity ratings, a three-dimensional multidimensional scaling solution was derived. Results suggested that listeners classified the stimuli into clusters based upon periodicity and the number of spectral peaks. Within each cluster, the stimuli were ordered according to frequency. Because individual differences in the overall weightings of features were large, separate solutions were derived for two subgroups of listeners, formed based upon similarities in the pattern of dimension weights obtained in the group analysis. One subgroup, for whom the full group analysis captured a large proportion of the variance in the ratings, included the adults, many of the 10-year-olds, and a few of the 7-year-olds. The solution derived for this subgroup suggested that spectral and temporal information were weighted equally and integrated into all dimension weights. Frequency information was coded but given less weight and was not used for stimulus classification. A second subgroup of listeners included most of the 7-year-old and some of the 10-year-old children. Examination of their data suggested that they relied heavily on an analysis of the signals according to periodicity as was reflected in their temporal fine structure. Also encoded but of lesser importance were aspects of spectral shape and absolute frequency.

Acoustics↗
PubMed1997

Haematoma block or Bier's block for Colles' fracture reduction in the accident and emergency department--which is best?

OBJECTIVE: To offer clear guidance on the anaesthetic management of Colles' fractures in the accident and emergency (A&E) department in the light of the conflict between existing reports and current trends, and to address the issue of alkalinisation of haematoma blocks. METHODS: This was a two centre, prospective, randomised clinical trial with consecutive recruitment of adult patients with Colles' fractures requiring manipulation to receive either Bier's block or haematoma block. There was subsequent blinded randomisation to alkalinised or non-alkalinised haematoma block. RESULTS: 72 patients were recruited into the Bier's block group, and 70 into the haematoma block group. Bier's block was less painful to give than the haematoma block (median pain score 2.8 v 5.3; P << 0.001), and fracture manipulation was also less painful in the Bier's block group (median pain score 1.5 v 3.0; P < 0.01). There was no significant difference in overall A&E transit time between the two groups. There was better initial radiological outcome in terms of dorsal angulation in the Bier's block group (-3.6 degrees v 2.1 degrees; P = 0.003). More remanipulations were required in the haematoma block group (17/70 v 4/72; P = 0.003). There was a trend towards decreased pain on administration of the alkalinised haematoma block when compared with non-alkalinised haematoma block, but this did not reach significance. There was no difference in pain score on fracture manipulation. There were no complications in either group. CONCLUSIONS: Bier's block is superior to haematoma block in terms of efficacy, radiological result, and remanipulation rate; transit times are equal, both procedures are practical in the A&E environment, and there were no complications. Bier's block is the anaesthetic management of choice for Colles' fractures requiring manipulation within the A&E department.

Adolescent↗
PubMed1996

A specific RNA structural motif mediates high affinity binding by the HIV-1 nucleocapsid protein (NCp7).

Current research indicates that the nucleocapsid protein (NCp7) of human immunodeficiency virus type 1 (HIV-1) interacts with a variety of RNA substrates during the progression of the viral life cycle. The RNA features specifically recognized by the protein, however, have yet to be identified. SELEX was used to generate a set of RNAs whose affinities for nucleocapsid were on the order of 2 x 10(-9) M. Comparative analysis revealed that each RNA contains a highly conserved fourteen nucleotide sequence-block. Computer modeling and structure probing experiments indicate that the RNA ligands use the consensus sequence to fold into hairpins with an identical asymmetric bulge. The presence of the nucleocapsid protein protects the asymmetric bulge from ribonuclease attack, suggesting that it is the key element in protein recognition. A search for similar structural motifs within the HIV genome reveals several potential interaction sites for the nucleocapsid protein.

Base Sequence↗
PubMed1996

Prognostic factors in the treatment of node-negative nonsmall cell lung carcinoma with radiotherapy alone.

PURPOSE: For patients with early stage nonsmall cell lung carcinoma (NSCLC) but medically inoperable, aggressive radiation therapy might impact on survival. METHODS AND MATERIALS: Between 1980 and 1990, 71 patients treated at MDACC by radiation therapy alone for NSCLC because of medical contradindications for surgery were analyzed. All patients had histologic or cytologic confirmation of NSCLC. The median total radiation dose was 63.23 Gy with 79% of patients receiving doses exceeding 60 Gy. The radiographic response was documented at completion of radiation therapy and 6 months after completion of radiation therapy. The median follow-up time was 36 months, ranging from 14-61 months. RESULTS: Overall survival rates at 3 and 5 years were 19 and 12%, respectively. The disease-specific survival (DSS) rates at 3 and 5 years were 44 and 32%, respectively. The DSS rates at 3 years by T-stage were: 49% for T1, 47% for T2, 26% for T3, and 32% for T4. The local control rates at 3 and 5 years were 66 and 56%, respectively. The local control rates at 3 years by T-stage were: 89% for T1, 61% for T2, 42% for T3, and 55% for T4. Univariately, the significant favorable prognostic factors for DSS were a KPS > or = 70, tumor size < or = 5 cm, no chest-wall invasion, and a radiation dose > or = 50 Gy. The significant favorable prognostic factors for local control were tumor size < or = 4 cm, no chest-wall invasion, a radiation dose > 60 Gy, and a complete response confirmed by chest x-ray at 6 months after radiotherapy (p = 0.04). Coverage of nodal drainage areas did not affect survival or local control. No lethal complications were seen, and documented symptomatic radiation pneumonitis occurred in only 7% of cases. Hence, the significant favorable prognostic factors for DSS were a KPS of > or = 70, tumor size < or = 5 cm, no chest-wall invasion, and a radiation dose > or = 50 Gy. The significant favorable prognostic factors for local control were tumor size of < or = 4 cm, no chest-wall invasion, a radiation dose > 60 Gy, and a complete response confirmed by chest x-ray at 6 months after radiotherapy. Multivariate analysis showed that the most important prognostic factor for DSS was KPS, and the most important prognostic factor for local control was radiation dose. CONCLUSIONS: Patients with a KPS of > or = 70, a tumor size < 5 cm, and no chest-wall invasion would benefit most from treatment with radiation alone to doses exceeding 60 Gy. This patient group represents the best sample for studying the benefit of conformal radiotherapy.

Carcinoma, Non-Small-Cell Lung↗
PubMed1996

Survival and growth of Aeromonas hydrophila on modified atmosphere packaged normal and high pH lamb.

The growth of A. hydrophila on normal pH (5.5-5.8) and high pH ( > 6.0) lamb stored under modified atmospheres was examined. Lamb pieces and mince, inoculated with A. hydrophila were packaged in air, vacuum pack, 80% O2/20% CO2, 50% CO2/50% N2, or 100% CO2 and stored at 5 or 0 degrees C for up to 42 days. Samples were examined for the survival and/or growth of A. hydrophila by enrichment in alkaline peptone water and/or direct plating on starch ampicillin agar. The pH of each sample was estimated. On lamb pieces and mince of normal pH, A. hydrophila numbers decreased during storage at 5 and 0 degrees C under all the packaging conditions. The organism was not detected after 21 days storage. In contrast, A. hydrophila numbers were maintained or increased on high pH lamb under most storage regimes. Storage at 5 degrees C allowed significant increases in A. hydrophila numbers on high pH lamb under all the atmospheres, except 100% CO2. In lamb held at 5 degrees C under 100% CO2 for up to 42 days, A. hydrophila was recovered from most samples, although cell numbers decreased during storage. After storage at 0 degrees C, A. hydrophila was recovered from high pH packs stored under all atmospheres. Significant increases in cell numbers were only observed in minced lamb of high pH stored under air or vacuum. The pH values of lamb pieces and mince held at 5 or 0 degrees C under any of the packaging atmospheres did not change in a uniform manner during storage.

Aeromonas hydrophila↗
PubMed1996

Electrophysiological analysis of the registration, storage and retrieval of information in delayed matching from samples.

Brain processes of registration, storage in working memory and retrieval of different kinds of information were studied by analysis of EEG and ERP activity recorded during two delayed matches from sample tasks: (1) matching the digits in two series of six numbers, and (2) matching the sums of the same two series of six numbers. each trial was composed of six intervals continuing six equally spaced visual stimuli: (1) control--observing a series of six fixation points, P1, on a computer monitor; (2) priming--viewing a series, S1, of six numbers; (3) delay--observing a second series of six fixation points, P2; (4) matching--viewing a second series, S2, of six numbers; (5) response selection--selecting the left button to press if S1 contained all the items in S2 or the right button if any item appeared only in S2, while observing six fixation points; (6) feedback--six color coded fixation points indicate correct or error. Each interval was 4 s in duration and 20 trials were presented in each task. During each interval the visual field flickered at a tracer frequency of 1.5/s, whether numbers or fixation points were on the monitor screen. Very narrow band power spectra (VNB), ERPs elicited by presentation of S1 or S2 information items, and non-contingent probes (NCP) elicited by presentation of fixation points were used to trace the processing of information by neural populations activated by the visual stimulation. Global field power maxima identified latencies at which functional landscapes were analyzed. VNB, ERP, NCP and landscape differences were found between digits and sums. However, though these differences were highly significant within each subject (p < 0.001), no consistency was found across individuals for the electrophysiological changes during the tasks. This suggests that utilization of brain resources in cognition varies greatly with individual cognitive styles and strategies.

Alpha Rhythm↗
PubMed1996

Development of auditory information integration abilities.

The ability of normal-hearing children (aged 4 through 7 years) and adults to integrate information was measured in an auditory sample discrimination task. On each trial a pair of tonal sequences was played whose component frequencies were randomly drawn from two equal-variance, Gaussian distributions with different means. The listeners task was to identify the sequence drawn from the distribution with the higher mean frequency. Performance was first evaluated as a function of the number of components in each sequence. Results showed that discrimination accuracy improved with increasing age until age 7, at which time performance was adult-like. The 7-year-olds and the adults discriminated the sequences with increasing accuracy as the sequence length was increased, but the 4-to 6-year-old listeners, as a group, did not. Data were fitted with a model with two free parameters, one representing resolution of the components and presumed to reflect peripheral processing, and another representing central noise added to the decision process after the component information is combined [R. Lutfi, J. Acoust. Soc. Am. 86, 934-944 (1989)]. On average, both parameters showed gradual changes as age increased, with adult-like values by 7 years of age. Individual data however suggest that the changes in central noise with age may be less gradual than the changes in peripheral resolution. In a second condition, increases in component duration produced improved performance for the 7-year-olds and the adults, while that of the younger listeners remained the same. Fitted parameters suggested improvements in component resolution for the older children, with no changes in central noise levels. In a third condition, reducing the overlap in the distributions improved performance for only a few of several younger children. This improvement was attributable to lower levels of central noise. Overall, these results suggest that with increasing age children are better able to discriminate between sounds that are variable and have overlapping acoustic characteristics. This age-related improvement may be attributed both to improvements in the ability to resolve the components and to reductions in central noise.

Adult↗