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Biomedical subjects

B Patel

Publications and source records attributed to B Patel.

At least 19 recordsLinked to original sources
PubMed2003

Core biopsy versus FNAC for palpable breast cancers. Is image guidance necessary?

The aim of this study was to assess the efficacy of free-hand percutaneous core biopsy (FHCB) and to determine the role of fine needle aspiration cytology (FNAC) as diagnostic tools for palpable radiologically-suspicious breast lumps. This retrospective study was based on reviewing the clinical records of all patients diagnosed as having breast cancer between January 1999 and December 2000 and patients who had benign lesions, but suspicious breast imaging at triple assessment. Absolute sensitivity of FHCB for diagnosing cancer in palpable lesions was 98.7% compared with 51.3% for FNAC. The difference in the sensitivity of FHCB and FNAC was statistically significant (P<0.005, Wilcoxon matched pair test). Since 94.8% of radiologically-suspicious lumps were shown to be cancers, we advocate FHCB for all patients presenting with radiologically suspicious palpable lumps to our breast clinic. We also conclude that the sensitivity of FHCB for the diagnosis of malignancy in palpable radiologically-suspicious breast lesions is so high that image-guidance is unnecessary.

Biopsy, Needle↗
PubMed2002

Image-guided surgery for anal fistula in a 0.5T interventional MRI unit.

PURPOSE: To determine whether MR-guided anorectal surgery is feasible, and to develop techniques for MR-guided anal fistula surgery. MATERIALS AND METHODS: Six patients with pilonidal sinus (PNS), and 21 with suspected anal fistulae were operated on in the GE Signa SPIO 0.5T interventional MRI unit. Procedures were performed with magnet-safe Lockhart-Mummery fistula probes. Preprocedural and intra-operative MRI (IOMRI) techniques were used to identify the extent of the fistula tracts and septic foci, and to ensure the adequacy of the surgical procedure. RESULTS: IOMRI demonstrated the PNS lesions and the adequacy of excision. Imaging failed to demonstrate a fistula in two patients, as confirmed by surgical examination. No images were obtained in one patient due to his size (weight in excess of 100 kg). In 18 patients a fistula tract or abscess was demonstrated and IOMRI was used to assess the adequacy of the surgical procedure. In three patients this demonstrated incomplete drainage of septic foci, which was not obvious on inspection of the surgical field. We believe that in these patients IOMRI prevented an incomplete procedure and the potential requirement for a second operation. Further surgery was performed to rectify this situation. The fistula tract was laid open in 13 patients, and a Seton drain was inserted in five. CONCLUSION: MRI-guided surgery for anal fistula is feasible. IOMRI demonstrates the exact anatomy of the tracts and abscesses, and confirms that all have been adequately treated. We believe it may become particularly useful in surgery for recurrent and complex anal fistulae, and may lead to fewer recurrences.

Adult↗
PubMed2002

Properties of neurotoxic peptides related to the BRI gene.

Mutations in the BRI gene are thought to cause dementias in members of families. The clinical symptoms are similar to those of Alzheimer's disease, but with additional ocular and hearing deficits, and spasticity. The mutations lead to the release of the 34-residue peptides, ABri and ADan, in the brains of afflicted individuals. We have synthesized the peptides in their straight-chain and oxidized cyclic forms and shown that the oxidized form of ABri and reduced form of ADan are toxic to human neuronal cell lines in culture. Neurotoxicity correlates with the extent of formation of SDS-stable non-fibrillar low-molecular-mass oligomers (SSNFOs).

Adaptor Proteins, Signal Transducing↗
PubMed2002

Determination of Helicobacter pylori vacA allelic types by single-step multiplex PCR.

AIMS: To develop and evaluate a novel multiplex PCR assay that enables definition of Helicobacter pylori vacA allelic type in a single reaction. METHODS AND RESULTS: Application of the one-step system to DNA extracts from 22 cultures of known vacA genotype demonstrated that it was highly accurate. Analysis of 15 matched gastric biopsy/culture pairs generated exactly correlating genotype profiles. vacA genotypes were determined from an additional 62/70 gastric biopsies from dyspeptic patients of known H. pylori positive status by the one-step assay, compared with 63/70 by the original two-reaction test. Types s1/m1, s1/m2 and s2/m2 were identified in 51.9%, 31.2% and 16.9% of biopsies, respectively. CONCLUSIONS: The multiplex PCR system developed enables rapid one-step vacA genotyping that is accurate, easy to interpret and more economical than the alternative multiple-reaction tests. Application of this system to gastric biopsies from patients in South-east England demonstrated that s1/m1 was the most common genotype, while s1/m2 and s2/m2 were less prevalent. SIGNIFICANCE AND IMPACT OF THE STUDY: This simple one-step system can be applied direct to antral gastric biopsies without the need for culture, thereby facilitating rapid surveillance of vacA genotype in relation to geographical location and disease status.

Alleles↗
PubMed2002

Extended acclimatization is required to eliminate stress effects of periodic blood-sampling procedures on vasoactive hormones and blood volume in beagle dogs.

Important in all experimental animal studies is the need to control stress stimuli associated with environmental change and experimental procedures. As the stress response involves alterations in levels of vasoactive hormones, ensuing changes in cardiovascular parameters may confound experimental outcomes. Accordingly, we evaluated the duration required for dogs (n = 4) to acclimatized to frequent blood sampling that involved different procedures. On each sampling occasion during a 6-week period, dogs were removed from their pen to a laboratory area and blood was collected either by venepuncture (days 2, 15, 34, 41) for plasma renin activity (PRA), epinephrine (EPI), norepinephrine, aldosterone, insulin, and atrial natriuretic peptide, or by cannulation (dogs restrained in slings; days 1, 8, 14, 22, 30, 33, 37, 40) for determination of haematocrit (HCT) alone (days 1 to 22) or HCT with plasma volume (PV; days 30 to 40). PRA was higher on days 2 and 15 compared with days 34 and 41 and had decreased by up to 48% by the end of the study (day 41 vs day 15; mean/SEM: 1.18/0.27 vs 2.88/0.79 ng ANG I/ml/h, respectively). EPI showed a time-related decrease from days 2 to 34, during which mean values had decreased by 51% (mean/SEM: 279/29 vs 134/20.9 pg/ml for days 2 and 34, respectively), but appeared stable from then on. None of the other hormones showed any significant variability throughout the course of the study. HCT was relatively variable between days 1 to 22 but stabilized from day 30, after which all mean values were approximately 6% lower than those between days 1 and 8. We conclude that an acclimatization period of at least 4 weeks is required to eliminate stress-related effects in dogs associated with periodic blood sampling.

Acclimatization↗
PubMed2001

Combination vaccines: postlicensure safety evaluation.

The success of immunizations in nearly eliminating many vaccine-preventable diseases has resulted in an increase in the need to study risks from vaccines, combination or otherwise. The well-known limitations associated with prelicensure trials have led many to hope that postlicensure studies can address safety issues. This article reviews measures that have been or should be taken to meet this expectation: establishment of clinical immunization safety assessment centers, standardization of case definitions for vaccine adverse events, use of the Vaccine Identification Standards Initiative to improve the accuracy and efficiency with which vaccination records are transferred, integration of vaccine safety monitoring into immunization registries, establishment (and enlargement) of the Vaccine Safety Datalink project, use of innovative analytic tools for better signal detection, and implementation of various methods to overcome confounding by contraindication. Only by investing in vaccine safety infrastructure at a level commensurate with investments in vaccine development can we hope to retain the public's confidence in immunization.

Adverse Drug Reaction Reporting Systems↗
PubMed2001

A means to an end: an overview of a hyperlipidemia outcomes management program.

Quality management and improvement are increasingly important to managed care organizations (MCOs) as competition increases. One key area on which quality improvement programs can focus is MCO activity in helping patients remain healthy. Screening for and treatment of hyperlipidemia are important components of the preventive care of patients who are at risk for coronary heart disease (CHD). This article summarizes the methodology of a three-phase hyperlipidemia outcomes management program being implemented by 27 US health plans. Phase 1 identifies inefficiencies in the clinical management of hyperlipidemia by assessing patients' attainment rates of low-density lipoprotein cholesterol (LDL-C) targets. This information is then used to develop a multifactorial intervention program for CHD prevention in phase 2. The interventions for physicians include provision of treatment algorithms for patients with varying degrees of hyperlipidemia, education programs encouraging appropriate treatment of hyperlipidemia, and academic detailing summarizing phase 1 results and providing applicable literature. In phase 3, patient records are reassessed at least 6 months after the educational intervention. This three-phase program has the potential to improve patient care, reduce unnecessary treatment costs, provide a means of quality improvement, and increase plan value to potential purchasers.

Cholesterol, LDL↗
PubMed2001

Elevated plasma amyloid beta-peptide 1-42 and onset of dementia in adults with Down syndrome.

We compared levels of plasma amyloid beta-peptides Abeta1-42 and Abeta1-40 in 108 demented and nondemented adults with Down syndrome (DS) and 64 adults from the general population. Abeta1-42 and Abeta1-40 levels were significantly higher in adults with DS than in controls (P=0.0001). Compared to nondemented adults with DS, Abeta1-42 levels in demented adults with DS were selectively increased by 26% (28.2 pg/ml vs. 22.4 pg/ml, P=0.004). In addition, mean plasma levels of Abeta1-42 were 22% higher in DS cases with the apolipoprotein varepsilon4 allele than in DS subjects without an varepsilon4 allele (25.9 pg/ml vs. 21.2 pg/ml, P=0.01), while mean plasma levels of Abeta1-40 did not vary by APOE genotype. These results support the hypothesis that Abeta1-42 plays an important role in the pathogenesis of dementia associated with DS, as it does in Alzheimer's disease, and that variations in plasma levels may be related to disease progression.

Adult↗
PubMed2001

Abnormal dendritic spine characteristics in the temporal and visual cortices of patients with fragile-X syndrome: a quantitative examination.

Fragile-X syndrome is a common form of mental retardation resulting from the inability to produce the fragile-X mental retardation protein. Qualitative examination of human brain autopsy material has shown that fragile-X patients exhibit abnormal dendritic spine lengths and shapes on parieto-occipital neocortical pyramidal cells. Similar quantitative results have been obtained in fragile-X knockout mice, that have been engineered to lack the fragile-X mental retardation protein. Dendritic spines on layer V pyramidal cells of human temporal and visual cortices stained using the Golgi-Kopsch method were investigated. Quantitative analysis of dendritic spine length, morphology, and number was carried out on patients with fragile-X syndrome and normal age-matched controls. Fragile-X patients exhibited significantly more long dendritic spines and fewer short dendritic spines than did control subjects in both temporal and visual cortical areas. Similarly, fragile-X patients exhibited significantly more dendritic spines with an immature morphology and fewer with a more mature type morphology in both cortical areas. In addition, fragile-X patients had a higher density of dendritic spines than did controls on distal segments of apical and basilar dendrites in both cortical areas. Long dendritic spines with immature morphologies and elevated spine numbers are characteristic of early development or a lack of sensory experience. The fact that these characteristics are found in fragile-X patients throughout multiple cortical areas may suggest a global failure of normal dendritic spine maturation and or pruning during development that persists throughout adulthood.

Adult↗
PubMed2001

Optimal reading speed in simulated cataract: development of a potential vision test.

Previous studies suggest that optimal reading speed is unaffected by cataract, yet is significantly reduced in age-related macular disease. This raises the question of whether a reading speed test could be developed to assess potential vision after cataract surgery. In this study, 20 young subjects, with and without a simulation of dense cataract, read aloud Bailey-Lovie word charts. From the results, critical print size, optimal reading speed and word acuity were calculated. The simulated cataract reduced word acuity and increased the critical print size, yet optimal reading speed remained unchanged. Measurements were also taken with the charts in reversed contrast polarity. Reversing the contrast polarity of the charts improved the word acuity and optimal reading speed with the cataract simulation. The results suggest that optimal reading speed could be used as a potential vision test. Further investigations using patients with cataract and ARMD are required.

Adult↗
PubMed2001

Stridor and difficult airway in an AIDS patient.

Kaposi's sarcoma (KS) is the most common malignancy observed in patients with acquired immune deficiency syndrome (AIDS). Although KS involves the head and neck in AIDS patients, difficult airway due to KS in an AIDS patient has rarely been reported in the literature. We report a patient with AIDS and cutaneous KS who developed inspiratory stridor and required an emergent tracheostomy. AIDS patients with cutaneous KS should have an assessment of the upper airway even in the absence of airway-related symptoms. If KS is present in the upper airway, fiber optic and/or radiologic studies are indicated to assess the extent of KS, and to define the appropriate interventions.

AIDS-Related Opportunistic Infections↗
PubMed2001

Loss of visual acuity is the main reason why reading addition increases after the age of sixty.

PURPOSE: To determine why the reading addition increases after the age of 55 to 60 years when accommodation is zero. METHODS: Distance and near visual acuities, arm length, habitual near working distance, reading addition, and pupil diameter were measured in 44 subjects aged >60 years (mean, 72.9 +/- 5.7). Reading addition values were attained using three techniques: least-plus addition using both N-notation text and MN-READ text and the cross-cylinder technique. RESULTS: The mean dioptric working distance was 2.75 +/- 0.40 D. The reading addition found using N-notation text (+2.21 +/- 0.38 D) was significantly lower than that measured using MN-READ text (+2.48 +/- 0.49 D) or the cross-cylinder method (+2.53 +/- 0.44 D). The reading addition was positively correlated with the dioptric working distance (r = 0.47, p < 0.01), and decreasing habitual working distance was associated with poorer visual acuity (r = -0.42, p < 0.01). CONCLUSIONS: Our results suggest that decreases in near visual acuity after 60 years of age lead to a reduction in habitual working distance, which increases text angular subtense. In turn, the reduced working distance requires a greater reading addition. Increases in depth of field associated with both suprathreshold text (N-notation) and lower visual acuity lead to reading additions being less than the dioptric working distance.

Accommodation, Ocular↗
PubMed2001

Development of a reading speed test for potential-vision measurements.

PURPOSE: Previous studies suggest that optimal reading speed is unaffected by cataract, yet is significantly reduced in age-related macular degeneration (ARMD ). This raises the question of whether a reading speed test could be developed to assess potential vision after cataract surgery. METHODS: Nineteen subjects with cataract, 15 with ARMD, and 13 control subjects with normal, healthy eyes read Bailey-Lovie word charts aloud, and subsequently, critical print size and optimal reading speed were calculated. Measurements were also taken with the charts in reversed-contrast polarity and after pupillary dilation. RESULTS: Although the subjects with cataract had reduced word acuity and increased critical print size, optimal reading speed was similar to that of the control group at a mean of approximately 100 wpm. Optimal reading speed in the subjects with ARMD was substantially worse (mean of 39 wpm). Reversing the contrast polarity of the charts slightly increased the word acuity and optimal reading speed of the subjects with cataract. CONCLUSIONS: The results suggest that optimal reading speed would be useful as a potential-vision test. The proposed test would use text size of at least 1.32 degrees (1.2 log minimum angle of resolution [logMAR]), and pupil dilation would be unnecessary. A reading test with black letters on a white background would be adequate, because charts with reversed-contrast polarity made minimal difference in reading speed.

Aged↗
PubMed2000

The comparative content of the mitochondrial phosphoglyceroyl-ATP-containing polymer, purinogen, in rat tissues.

Here, we describe an assay for the tissue content of purinogen, a highly phosphorylated labile polymer containing ATP and phosphoglycerate found in the mitochondrial intermembrane space. We report the purinogen content (as adenine nucleotide equivalents) of rat heart and, for the first time, of rat liver, kidney, brain and mixed skeletal muscle. The findings show that purinogen contains very significant proportions of cell adenine nucleotides ranging from 25% of the free pool in brain and skeletal muscle to 135% of it in kidney. The evidence that purinogen may form a controlled intracellular reservoir of inorganic phosphate is briefly discussed.

Adenine Nucleotides↗