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Biomedical subjects

P Mathews

Publications and source records attributed to P Mathews.

At least 19 recordsLinked to original sources
PubMed2000

Nursing and respiratory: partners in care.

Learn about RCP licensure and nursing's support of this process, as well as the clinical advancements, new and altered procedures, and novel applications of drugs and devices in respiratory care.

Certification↗
PubMed1999

Voice changes and thyroid surgery: is pre-operative indirect laryngoscopy necessary?

BACKGROUND: Indirect laryngoscopy (IDL) is often performed prior to thyroid surgery to detect pre-existing vocal cord pathology. METHODS: A retrospective chart review of 201 patients undergoing thyroid surgery at the Prince of Wales Hospital was undertaken in order to study the patterns of pre-operative and postoperative voice changes and IDL findings. RESULTS: A total of 9% of patients had pre-operative voice symptoms, and 22% of this group had abnormalities detected on pre-operative IDL. Of 160 documented IDL, 4% revealed vocal cord pathology in asymptomatic patients, including an asymptomatic recurrent laryngeal nerve palsy. CONCLUSIONS: Indirect laryngoscopy remains a useful but flawed pre-operative screening tool for patients with voice symptoms, but the literature suggests that more advanced phoniatric tests will provide superior diagnostic sensitivity. The role of routine pre-operative laryngoscopy for asymptomatic patients is of debatable value.

Hoarseness↗
PubMed1999

Mycobacterium fortuitum endocarditis and meningitis after balloon mitral valvotomy.

Mycobacteria rarely cause endocardial infections. We describe the clinical course of a patient who developed endocarditis, and meningitis with Mycobacterium fortuitum following balloon mitral valvotomy. The patient was treated with amikacin and clarithromycin but did not respond. She developed haemolytic anaemia as the terminal event.

Adult↗
PubMed1998

Movement detection at the human big toe.

1. To be detected, movements of the interphalangeal joint of the big toe must be greater than at other joints. This poor acuity may arise because the anatomy of the foot and ankle results in poor coupling between the toe and the muscles that operate it. To vary this coupling, the effect of ankle position on proprioceptive acuity at the toe was measured. 2. We measured proprioceptive acuity at the toe with the ankle in different positions and found that ankle plantarflexion did improve acuity. This implies that, with the ankle at mid-range or dorsiflexed, toe movement is inadequately transferred to muscle fascicles. 3. To determine actual changes in fascicle length of the toe extensor, movements of extensor hallucis longus near the toe and at the muscle-tendon junction were measured during surgical exposure in one subject. Ankle position greatly affected movement transfer from toe to muscle-tendon junction: no tendon movement was transferred with the ankle dorsiflexed, but all movement was transferred with the ankle plantarflexed. 4. When the relationship between joint rotation and muscle fascicle length measured in vivo was used to express the smallest detectable movements of the toe as proportional changes in muscle fascicle length, these detectable changes were similar to those at all other limb joints. This suggests that change in muscle fascicle length is of major interest to the nervous system.

Adult↗
PubMed1998

Expression of androgen receptor and growth factors in premalignant lesions of the prostate.

Analysis of growth factors and receptors in putative premalignant lesions of prostatic adenocarcinoma should aid our understanding of their growth pathways. Sixty prostatic TURP (transurethral resection of the prostate) specimens exhibiting atypical adenomatous hyperplasia (AAH) and/or prostatic intraepithelial neoplasia (PIN) lesions were assayed by immunohistochemistry for androgen receptor (AR), epidermal growth factor receptor (EGFR), c-erbB-2, transforming growth factor-alpha (TGF-alpha), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), MIB-1, E-cadherin, and high molecular weight keratin. Expression of these factors in the lesions was compared with that in the co-existing benign prostatic hyperplasia (BPH) or prostatic adenocarcinoma. Strong AR nuclear staining was observed in the luminal cells, but not the basal cells, of BPH and PIN lesions and in all the carcinomas examined. A similar growth factor and receptor profile was demonstrated in the secretory epithelium of high-grade PIN and carcinoma with a tendency to higher expression of membranous EGFR and c-erbB-2 and cytoplasmic TGF-alpha, and lower levels of FGF-2 than in low-grade PIN or BPH glands. Also, increased rates of proliferation, as estimated by MIB-1 stained cells, were observed in high-grade PIN in comparison with low-grade PIN and BPH and were not confined to the basal layer. AAH lesions resembled neither BPH nor carcinoma. Proliferation was virtually absent (MIB-1 expression); both AR and E-cadherin expression was significantly reduced; and, with the exception of FGF-2, all the other growth factors and receptors studied were absent. The results presented would support a premalignant role for high-grade PIN, whilst AAH would appear to represent a quiescent phenotype unlikely to progress to neoplasia.

Antigens, Nuclear↗
PubMed1998

The Griess test: an inexpensive screening test for asymptomatic bacteriuria in pregnancy.

This study was designed to compare urine microscopy and the Griess test as screening tests for asymptomatic bacteriuria (AB) in pregnancy, using urine culture as a gold standard. Urine microscopy, Griess test and urine culture were carried out on urine samples from 483 antenatal women. AB was detected by urine culture in 30 (6.8%) of the patients. The Griess test and urine microscopy were found to have a sensitivity of 63.3% and 60%, specificity of 99.5% and 83.6%; and positive predictive value of 90.5% and 21.1% respectively. Most of the infections missed by the Griess test were either <100,000 colony count on culture or caused by gram positive cocci. The cost of the Griess test was only one tenth of that of urine microscopy. The Griess test is a simple and inexpensive test that when compared to urine microscopy has equal sensitivity, and better specificity and positive predictive value for the detection of AB in pregnancy than urine microscopy.

Bacteriological Techniques↗
PubMed1997

Cellular expression and proteolytic processing of presenilin proteins is developmentally regulated during neuronal differentiation.

We have determined the expression of the Alzheimer's disease-associated proteins presenilin-1 and presenilin-2 in primary cultures of rat hippocampal neurons. Neurons highly express presenilin-1 and presenilin-2, whereas both proteins were not detected in astrocytes. Further, we have analyzed the subcellular localization and expression in rat hippocampal neurons during development. Although presenilin proteins were localized predominantly to the endoplasmic reticulum in nonneuronal cells transfected with presenilin cDNAs, in neurons, presenilin proteins were also found in compartments not staining with antibodies to grp78(BiP). Presenilin-1 and presenilin-2 were predominantly detected in vesicular structures within the somatodendritic compartment with much less expression in axons. Polarized distribution of presenilin-1 and presenilin-2 differs slightly, with more presenilin-2 expressed in axons compared with presenilin-1. Presenilin expression was found to be developmentally regulated. Presenilin expression strongly increased during neuronal differentiation until full morphological polarization and then declined. No full-length presenilin-1 or presenilin-2 could be detected within cell lysates. At early developmental stages the expected approximately 34-kDa N-terminal proteolytic fragment of presenilin-1 and the approximately 38-kDa fragment of presenilin-2 were detected. Later during differentiation we predominantly detected a approximately 38-kDa fragment for presenilin-1 and a approximately 42-kDa fragment for presenilin-2. By epitope mapping, we show that these slower migrating peptides represent N-terminal proteolytic fragments, cleaved C-terminal to the conventional site of processing. It is noteworthy that both presenilin-1 and presenilin-2 undergo alternative proteolytic cleavage at the same stage of neuronal differentiation. Regulation of presenilin expression and proteolytic processing might have implications for the pathological as well as the biological function of presenilins during aging in the human brain.

Animals↗
PubMed1996

Degradation and endoplasmic reticulum retention of unassembled alpha- and beta-subunits of Na,K-ATPase correlate with interaction of BiP.

Assembly of alpha- and beta-subunits in the endoplasmic reticulum is a prerequisite for the structural and functional maturation of oligomeric P-type ATPases. In Xenopus oocytes, overexpressed, unassembled alpha- and beta-subunits of Xenopus Na,K-ATPase are retained in the endoplasmic reticulum (ER) and are degraded with different kinetics, while unassembled beta-subunits of gastric H, K-ATPase leave the ER. In this study, we have investigated the role of the immunoglobulin-binding protein, BiP, in the folding, assembly, and ER retention of ATPase subunits. We determined the primary sequence of Xenopus BiP and used polyclonal antibodies to examine the interaction with BiP of various wild type and mutant alpha- and beta-subunits overexpressed in Xenopus oocytes. Our results show that ER-retained, unassembled Na,K-ATPase beta-subunits, but not transport-competent H,K-ATPase beta-subunits, efficiently associate with BiP until assembly with alpha-subunits occurs. Furthermore, the kinetics of BiP interaction with unassembled wild type and with mutant Na,K-ATPase beta-subunits parallels their respective stability against cellular degradation. Finally, alpha-subunits that are overexpressed in oocytes and are rapidly degraded and endogenous oocyte alpha-subunits that are stably expressed as individual assembly-competent proteins also interact with oocyte or exogenous BiP, and the interaction time correlates with the protein's stability. These data demonstrate for the first time that BiP might be involved in a long term maturation arrest and/or in the ER quality control of a multimembrane-spanning protein and lend support for a universal chaperone function of BiP.

Animals↗
PubMed1994

Glomerular filtration rate in Indian non-insulin-dependent diabetics at various stages of albuminuria.

Sixty-seven non-insulin-dependent diabetic subjects were selected to estimate the glomerular filtration rate (GFR). All patients had satisfactory glycaemic control (HbA1 < 9.5%). GFR was determined using Technetium 99m DTPA by the method devised by Gates. Thirty-eight subjects had normal albumin excretion (UAE < 20 micrograms/min), 15 had UAE in the microalbuminuric range (20-100 micrograms/min), and the rest were macroalbuminuric (> 200 micrograms/min). GFR was lower in the normoalbuminuric patients as compared to the controls, but the decrease was not significant (71.5 (21.4) vs. 98.3 (16.1) ml/min per 1.73 m2. GFR was significantly decreased in both micro and macroalbuminuric groups (64.0 (24.5) and 53.8 (27.3) ml/min per 1.73 m2, respectively) (P < 0.05). No appreciable change in GFR was observed in normoalbuminuric patients with increasing duration of diabetes, however, there was a steady decline in GFR with time in both micro- and macroalbuminuric patients. Hypertension was present in 79%, 47% and 16% of macro-, micro- and normoalbuminuric patients, respectively. GFR was significantly lower in hypertensive diabetic patients compared to normotensives (52.3 vs. 76.1 ml/min per 1.73 m2) (P < 0.01), while this difference was not significant in the micro- and macroalbuminuric groups. We conclude from our study that the stage of hyperfiltration could not be detected in non-insulin-dependent diabetes and that hypertension has a significant influence on the rate of decline of GFR.

Adult↗
PubMed1994

Caregiver involvement in a large clinical systems project.

The Kaiser Permanente Northern California Region (KPNCR) CareGiver Workstation (CGW) Project's mission is to develop and implement a clinical workstation system that will enhance each caregiver-member interaction and aid in the decision-making processes of direct patient care in the inpatient and outpatient settings. The requirements analysis approach for CareGiver Workstation (CGW) is based on the belief that extensive caregiver involvement will provide a better understanding of the diverse needs of Kaiser Permanente Northern California Region (KPNCR). In order to involve as many caregivers as reasonably possible, CGW included a 16 member caregiver core team and 6 different Medical Centers in the requirements definition process. The Medical Centers are referred to as "focus facilities". A "focus group" (caregiver team) at each selected focus facility consisted of a site coordinator and a 24-30 person multidisciplinary team involving physicians, nurses, therapists and other caregivers. The Medical Center selection process identified facilities that provided the best cross-sectional representation of KPNCR. The Lead Focus Facility participated in the initial round of requirements definition activities. These sessions assisted in the design of a simulation that was used at five additional Medical Centers to validate requirements. The five additional Focus Facilities participated in simulation review sessions. Feedback from these sessions was used to revise the simulation and update the requirements document. Caregivers from all six focus facilities and other identified groups participated in a requirements survey to assist CGW with identification of high priority features. Caregiver commitment and continuing involvement are essential for the success of CGW.(ABSTRACT TRUNCATED AT 250 WORDS)

California↗
PubMed1990

Spontaneously occurring antibodies to parathyroid hormone.

A 76-yr-old female with acute pancreatitis and a normal/borderline elevated serum calcium level was found to have an elevated immunoreactive circulating PTH concentration using a C-terminal assay. This high PTH concentration misled the attending physicians and resulted, in retrospect, in an unnecessary neck exploration. When the patient's serum was examined it was found to contain a binding component that bound both C-terminal and PTH-(1-84). This binding component was not retained on a Sep-Pak column and was precipitated by antiserum directed against human immunoglobulin M. The presence of circulating anti-PTH immunoglobulin M explains the apparently high PTH concentrations measured by RIA. The antibodies occurred spontaneously. To the best of our knowledge, this phenomenon has not previously been described.

Acute Disease↗
PubMed1989

Further studies of hippocampal representation during odor discrimination learning.

The contribution of hippocampal and nonhippocampal memory processing to simultaneous-cue odor discrimination learning was assessed. In this task, rats with hippocampal system damage consequent to fornix lesions (fornix rats) were severely and persistently impaired in discrimination learning, acquisition of learning set, and concurrent discrimination, although they occasionally solved some problems at a normal rate. By using those problems on which fornix rats succeeded, to permit comparisons of performance strategies with normal rats, differences between groups were shown on response latency measures and on probe trials involving the novel pairing of familiar odors. Normal rats had a bimodal distribution of response latencies, and their latency depended on where the S+ was presented. Fornix rats had short response latencies and responded equally quickly wherever the S+ was presented. Furthermore, when the representation of familiar S+ and S- odor pairs was challenged in probe trials, normal rats responded appropriately to the correct stimulus, whereas fornix rats behaved as if presented with a new odor pair. These data provide support for the view that the hippocampus participates in the representation of relations among odor (and other) stimuli and among other experiences and that it permits the flexible use of these representations in new contexts. In contrast, memory processing outside the hippocampal system can represent only the significance of individual stimuli and can be revealed only in a repetition of the original learning event.

Animals↗
PubMed1988

Hippocampal system dysfunction and odor discrimination learning in rats: impairment or facilitation depending on representational demands.

The performance of normal rats and that of rats with hippocampal system damage were compared on acquisition of different versions of the same two-odor discrimination task that placed different encoding and representational demands on memory. Rats with fornix lesions were impaired when explicit comparisons among multiple odor cues and differential response choices were encouraged. However, when odor-cue comparison was hindered and explicit cues for response choice were eliminated, rats with fornix lesions out performed normal animals. The results support an hypothesis that the hippocampal system is critical to a memory representation based on encoding relations among multiple percepts, and other brain systems support performance adaptations based on encodings of stimuli individually.

Animals↗