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Biomedical subjects

A Pollard

Publications and source records attributed to A Pollard.

At least 19 recordsLinked to original sources
PubMed1996

Clinical associations of anti-lamin autoantibodies.

BACKGROUND: The clinical associations of anti-lamin autoantibodies were first described in 1973. Since then a number of individual case reports and two small series have been published. These have suggested an association with connective tissue disorders and autoimmune liver disease. AIMS: To identify the clinical and laboratory associations of anti-lamin autoantibodies in an Australian population. METHODS: Retrospective review of routine antinuclear antibody testing between 1990-1994 for characteristics linear staining of nuclear envelope on indirect immunofluorescence on HEp-2 cells with clinical status defined by retrospective review of case records. RESULTS: Twenty-eight patients were identified and the clinical status of 27 patients defined. Eleven patients had associated IgG anti-cardiolipin antibodies; anti-phospholipid syndrome was present in nine. Seven further patients had liver disease; five had autoimmune liver disease, with associated autoantibodies. The remaining nine patients had a diverse group of diseases. There was no correlation between the titre of the autoantibody and clinical status. An association with anti-cardiolipin antibodies was found although the cause remains obscure. CONCLUSION: Anti-lamin autoantibodies, as identified by indirect immunofluorescence, are associated with a diverse group of diseases but particularly with anti-phospholipid syndrome and liver disease. Testing for anti-phospholipid antibodies and more specific markers of systemic lupus erythematosus and autoimmune disease, for example anti-dsDNA antibodies, anti-smooth muscle antibodies and anti-mitochondrial antibodies should be pursued when anti-lamin autoantibodies are detected.

Adult↗
PubMed1995

125I-RIA kit cannot distinguish vitamin D deficiency as well as a more specific assay for 25-hydroxyvitamin D.

OBJECTIVES: To compare a new radioimmunoassay (RIA), measuring vitamin D metabolites, against an established, competitive-protein binding assay (CPBA) that uses rat vitamin D binding protein. METHODS: For the CPBA, we first isolated 25-hydroxyvitamin D (25(OH)D) by eluting sample through silica cartridges. For the RIA, serum was added to acetonitrile and centrifuged, followed by RIA using 125I-25(OH)D3. RESULTS: The within-run CV was 1.5% to 4.1% by RIA, compared to 8.1% to 15.0% by CPBA. For both methods, analytical recovery was not significantly different from 100%, and both methods were appropriately linear with sample dilution. We compared RIA values (y axis) from 90 subjects with 25(OH)D ranging from 11 to 232 nmol/L by CPBA (x axis). The slope was 0.9992 (not significantly different from 1). However, the RIA exhibited a bias of 11.15 nmol/L (p < 0.05 vs 0), and a correlation coefficient of r = 0.923. When the comparison was confined to the 37 samples in the lower half of our reference range, the RIA did not compare well: slope, 0.764 (p < 0.05 vs 1.0); intercept 18.7 nmol/L (p < 0.05 vs 0); r = 0.517. For the samples below 36 nmol/L by CPBA, there was no discrimination by RIA between the 11 values below, and the 11 above the decision level (25 nmol/L by CPBA) for vitamin D deficiency. CONCLUSIONS: We conclude that the RIA is not optimized to detect vitamin D deficiency, and for this purpose it is not a valid substitute for conventional 25(OH)D methods.

Binding, Competitive↗
PubMed1993

Near-infrared spectroscopic determination of serum total proteins, albumin, globulins, and urea.

We have determined total protein, albumin, globulins, and urea in unmodified human serum using near-infrared (NIR) spectroscopy. The distinctive NIR spectrum of the individual protein fractions allowed unique spectroscopic models to be derived for each fraction using multiple linear least-squares regression (MLR). A more sophisticated partial least-squares (PLS) regression analysis was necessary to fully extract the relevant spectral information for urea. The serum protein data sets consisted of 235 calibration samples and 85 prediction samples. The total protein calibration yielded a multiple correlation coefficient (R) of 0.986 and a standard error of calibration (SEC) of 1.7 g/L. For the validation data set, a correlation coefficient (r) of 0.985 and standard error of prediction (SEP) of 1.7 g/L were obtained. For albumin, the values were R = 0.982 and SEC = 1.2 g/L for calibration and r = 0.984 and SEP = 1.1 g/L for prediction. Calibration results for globulins were R = 0.916 and SEC = 2.1 g/L; validation results were r = 0.885 and SEP = 2.2 g/L. The sum of the separately estimated albumin and globulin fractions agreed well with the total protein estimate. For urea, the calibration model (n = 422) provided an R = 0.994 and SEC = 0.7 mmol/L and the validation results (n = 208) were r = 0.993 and SEP = 0.8 mmol/L. The within-day and between-day precision values (CVs) were respectively, 1.2 and 1.3% for total protein, 1.7 and 1.1% for albumin, 1.5 and 1.3% for globulins, and 8.3 and 5.5% for urea.

Blood Proteins↗
PubMed1992

Carpal arch alteration and related clinical status after endoscopic carpal tunnel release.

One hundred eight endoscopic carpal tunnel releases were performed by a modification of the technique described by Chow. Eighty-seven of the 108 cases were evaluated for quantitative postoperative widening of the transverse carpal arch. The average postoperative widening of the transverse carpal arch was 0.17 cm (7%), with a range of 0 to 0.5 cm. Seventy percent of the patients showed 0% to 10% widening, 26% showed 10% to 20% widening, and 4% showed more than 20% widening of the transverse carpal arch. Preliminary findings show that 3 weeks after endoscopic carpal tunnel release, pinch strength was at 102% and grip strength at 86% of preoperative values. Six weeks after surgery, pinch strength was 106% and grip strength was 121% of preoperative values. The complication rate in this series was 3%. The transverse dimension of the carpal arch generally widens after endoscopic carpal tunnel release but to a lesser degree than has been reported for open carpal tunnel release. The rate of improvement of pinch and grip strength after endoscopic release is faster than that reported in the literature after open release.

Activities of Daily Living↗
PubMed1992

Near-infrared spectrophotometry: a new dimension in clinical chemistry.

The near-infrared (NIR) spectral region (700-2500 nm) is a fertile source of chemical information in the form of overtone and combination bands of the fundamental infrared absorptions and low-energy electronic transitions. This region was initially perceived as being too complex for interpretation and consequently was poorly utilized. Advances in chemometric techniques that can extract massive amounts of chemical information from the highly overlapped, complex spectra have led to extensive use of NIR spectrophotometry (NIRS) in the food, agriculture, pharmaceutical, chemical, and polymer industries. The application of NIRS in clinical laboratory measurements is still in its infancy. NIRS is a simple, quick, nondestructive technique capable of providing clinically relevant analyses of biological samples with precision and accuracy comparable with the method used to derive the NIRS models. Analyses can be performed with little or no sample preparation and no reagents. The success of NIRS in any particular case is determined by the complexity of the sample matrix, relative NIR absorptivities of the constituents, and the wavelengths and regression technique chosen. We describe the general approach to data acquisition, calibration, and analysis, using serum proteins, triglycerides, and glucose as examples.

Algorithms↗
PubMed1991

Relevance of vitamin D metabolite concentrations in supporting the diagnosis of primary hyperparathyroidism.

We compared the relationships between 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] levels in patients with primary hyperparathyroidism (PHPT) and 38 volunteer blood donors. There was no significant difference in mean 25(OH)D levels between patients with PHPT (34 +/- 21 nmol/L; n = 21) and the donor samples (41 +/- 19 nmol/L; n = 38). Serum 1,25(OH)2D levels were higher in the patients with PHPT compared with the donors (122 +/- 61 pmol/L vs 56 +/- 41 pmol/L; p less than 0.001). The 95th percentile 1,25(OH)2D value for the donors was exceeded in 65% of the patients with PHPT. There was a significant correlation between serum 1,25(OH)2D versus 25(OH)D in the patients with PHPT (r = 0.50; p less than 0.05) but not in the donors (r = 0.02). We conclude from the distinct elevation in 1,25(OH)2D levels in the majority of our patients with PHPT that the concentration of this parathyroid hormone-dependent hormone can be of critical value in corroborating the diagnosis of PHPT.

Adult↗
PubMed1990

Oral calcium load test: diagnostic and physiologic implications in hyperparathyroidism.

An oral calcium load test (CLT) (1 gm Ca/50 kg) was administered to 11 control subjects and 35 patients with overt hyperparathyroidism to assess its efficacy in diagnosis of hyperparathyroidism. All participants were placed on a low-calcium diet 3 days before the CLT. Intact parathormone and ionized calcium (Cai) levels were measured 0, 1, 2, and 3 hours after CLT. Initial Cai and parathormone (mean +/- SE) were 1.22 +/- 0.01 mmol/L and 2.94 +/- 0.03 pmol/L in the control group compared with 1.43 +/- 0.02 mmol/L and 10.6 +/- 2.2 pmol/L in the group with hyperparathyroidism. Both groups had a similar percent increase in Cai values (control, 5.9% +/- 0.8%; hyperparathyroidism, 6.3% +/- 0.6% (p greater than 0.1). A decline in parathormone levels of 47.6% +/- 2.8% in patients with hyperparathyroidism was significantly less than the 75.3% +/- 5.3% decline observed in control subjects (p less than 0.025). Three hours after CLT, parathormone was suppressed in control subjects, whereas a rebound occurred in patients with hyperparathyroidism. Postoperative CLT demonstrated a higher mean percent Cai increase and percent parathormone decline (Cai, 8.9% +/- 1.1%; parathormone, 67.9% +/- 1.8%) compared with preoperative values (Cai, 6.0% +/- 1.0%; PTH, 49.6% +/- 4.3%) (p less than 0.025), and 3 hours after calcium intake, parathormone remained suppressed, similar to control subjects. After surgery, three patients had elevated parathormone and low normal Cai levels and parathormone response to a CLT confirmed the diagnosis of secondary hyperparathyroidism. In conclusion, a CLT (1) can confirm the diagnosis of hyperparathyroidism and successful parathyroidectomy, (2) distinguished postoperative secondary from persistent primary hyperparathyroidism, (3) demonstrated nonautonomy of abnormal parathyroid glands with a parathormone response to a calcium load characterized by an earlier nadir, decreased suppressibility, and more rapid recovery, and (4) produced dynamic changes that did not distinguish patients with hyperparathyroidism from control subjects or hyperplasia from adenoma.

Administration, Oral↗
PubMed1990

Intraoperative parathormone level measurement in the management of hyperparathyroidism.

To investigate the potential use of intraoperative intact parathormone measurements to predict curative parathyroidectomy, we measured ionized calcium (Cai) levels and parathormone levels in 33 patients with hyperparathyroidism who underwent exploratory bilateral neck surgery. Nineteen patients each had a solitary adenoma, 13 patients had hyperplasia, and one patient had four normal parathyroid glands. These results were compared to the results for 37 patients who underwent either thyroid lobectomy (TL) (n = 10) or near-total thyroidectomy (NTT) (n = 27) and of 14 control patients who underwent miscellaneous operations. Parathormone decline after curative parathyroidectomy was 86.4 +/- 1.2% (mean +/- SE), which was significantly greater than a decline of 25.7% +/- 9.8% in three patients with persistent postoperative hyperparathyroidism (p less than 0.01). Declines were 38.5% +/- 8.7% after TL (p less than 0.01), 52.2% +/- 5.9% after NTT (p less than 0.01), and 8.3% +/- 4.3% (p less than 0.01), in the control patients. An intraoperative Cai decline of 4.0% +/- 0.6% after curative parathyroidectomy did not differ significantly from the results after TL, NTT, or miscellaneous operations in the control patients. Patients with persistent postoperative hyperparathyroidism had the greatest decline in Cai levels (7.1% +/- 2.3%; p less than 0.05). From these data we conclude that (1) a decline in parathormone level of 70% or more 20 minutes after parathyroidectomy is predictive of cure, (2) thyroidectomy, even unilaterally, produces a significant decline in parathormone level that affects interpretation of intraoperative parathormone level changes, (3) Cai level because of its slow decline is not useful in predicting effective parathyroidectomy, and (4) measurement of intraoperative parathormone level changes should not be used as a substitute for exploratory bilateral neck surgery.

Adult↗
PubMed1989

Lactase deficiency in Singapore-born and Canadian-born Chinese.

Seventy-three of 77 adult Singapore-born Chinese (95%) and 48 of 49 Canadian-born adult Chinese (98%) were demonstrated to be lactase deficient using the lactose breath hydrogen test. The similar prevalence of lactase deficiency in the Singapore- and the Canadian-born Chinese despite a larger estimated amount of daily milk ingestion in the Canadian-born Chinese (430 ml vs 157 ml) supports the concept that lactase deficiency, which is transmitted genetically, does not have an adaptable component related to the quantity of lactose ingested. When the lactose breath hydrogen test performed with a dose of 0.5 g/kg of lactose was compared with the test using a standard dose of 50 g of lactose, there was very little loss of sensitivity. In spite of the presence of lactase deficiency, only 32% of the Singapore subjects and 23% of the Canadian subjects had gastrointestinal symptoms when milk was ingested in the daily diet. Peak breath H2 was higher in females than males, but the difference was more significant in the Canadian cohort.

Adolescent↗
PubMed1989

Inhibition of T-lymphocyte mitogenic responses and effects on cell functions by bovine herpesvirus 1.

The mitogenic response of bovine peripheral blood mononuclear cells stimulated by concanavalin A (ConA) was suppressed by infectious bovine herpesvirus 1 (BHV-1). Proliferation in response to interleukin-2 (IL-2) by IL-2-dependent lymphocyte cultures was also inhibited by BHV-1. Although inhibition of mitogenesis approached 100%, less than 1 cell in 1,000 was productively infected by BHV-1 in ConA-stimulated cultures. Neither conditioned medium from mitogen-stimulated peripheral blood mononuclear cell cultures nor human recombinant IL-2 reversed suppression by the virus. Infection by BHV-1 did not influence the expression of IL-2 or IL-2 receptor mRNA in ConA-stimulated cultures, nor did it affect the cytolytic capabilities of lymphocytes. The data suggest that the inhibition of T-lymphocyte proliferation is the result of a nonproductive BHV-1 infection.

Animals↗
PubMed1986

Detection of a homologous series of C26-C38 polyenoic fatty acids in the brain of patients without peroxisomes (Zellweger's syndrome).

The brains of patients with inherited abnormalities in peroxisomal structure and function contain greatly increased proportions of a homologous series of unique polyenoic fatty acids with carbon chain lengths ranging from 26 to 38. Based on evidence by chemical ionization and electron impact mass spectrometry before and after catalytic hydrogenation, and argentation t.l.c., these lipids have been tentatively identified as 26:5, 28:5, 30:5, 30:6, 30:7, 32:5, 32:6, 32:7, 34:5 and 34:6 fatty acids. A further two fatty acids eluting at very high temperatures from gas chromatography columns have been tentatively identified on the basis of their chemical ionization mass spectra as 36:6 and 38:6 fatty acids.

Brain↗
PubMed1986

Dominantly inherited cardioskeletal myopathy with lysosomal glycogen storage and normal acid maltase levels.

A family is presented in which 7 members over 3 generations were affected by cardioskeletal myopathy. A vacuolar myopathy with excessive free and intralysosomal glycogen storage in skeletal and cardiac striated muscle was identified in biopsy studies. Post-mortem studies in several patients revealed changes of a congestive cardiomyopathy with myocardial fibrosis. Acid maltase, phosphorylase, debrancher and lysosomal enzyme screens, and glycolytic enzyme levels in skeletal muscle, were normal in 1 case. This is the third report of non-acid maltase deficient lysosomal glycogen storage disease and adds to previous reports with the presentation of detailed family studies, examined of ante- and post-mortem cardiac histology and reports of detailed glycolytic and lysosomal enzyme analysis. This syndrome is unusual among glycogenoses in having a dominant inheritance pattern.

Adult↗
PubMed1986

Electrophoretic characteristics of macro creatine kinase type 2 in serum.

We have studied the electrophoretic characteristics of a creatine kinase (CK, EC 2.7.3.2) isoenzyme, macro creatine kinase type 2 (MCK-2), in the serum of 42 patients with carcinoma of the colon. The patients could be divided into three subgroups by the intensity of the MCK-2 band (nine high, nine medium, and 24 low intensity), but we detected no correlation between the isoenzyme activity and the stage of the cancer. Inhibition of the activity of the CK-M subunit by antibody to CK-M allowed more sensitive detection of MCK-2 in serum and revealed that MCK-2 may be obscured by CK-MM. Moreover, there may be major discrepancies between the amount of MCK-2 seen on electrophoresis and the apparent total CK.

Colonic Neoplasms↗