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Biomedical subjects

M R Pudek

Publications and source records attributed to M R Pudek.

36 records · Page 2Linked to original sources
PubMed1984

Perinatal changes in a digoxin-like immunoreactive substance.

An endogenous digoxin-like immunoreactive substance(s) (DLIS) exists in the serum of premature and full term infants not receiving digoxin. We followed serum changes in DLIS concentration sequentially over the first 14 postnatal days in 24 premature neonates who did not receive digoxin in the intensive care nursery. All infants had measurable levels (greater than 0.6 ng/ml) of DLIS in their serum. There was a distinct peak in DLIS concentration in 19 of 24 infants occurring at 4 +/- 1.6 (SD) days after birth (range, 1-8 days). No peak was found in five infants. The peak serum level of DLIS obtained in the first 8 days of life was negatively correlated with gestational age and birth weight. DLIS levels in amniotic fluid remained constant from 16 to 33 weeks of gestation but rose from 33 wk to term. DLIS concentrations in umbilical artery, umbilical vein, and maternal serum at normal full term delivery suggested that DLIS was of fetal origin. DLIS and digoxin concentrations are additive when present in the same serum sample if measured by standard radioimmunoassay methods.

Aging↗
PubMed1983

Antibody interference with biochemical tests and its clinical significance.

Antibody interference with routine biochemical tests is becoming increasingly recognized as a cause of spurious results. It is important to recognize these interferences because inappropriate investigation may be instituted in response to the abnormal test result. The present review deals with the various biochemical tests in which antibody interference occurs. The tests include measurement of enzymes, hormones, immunoglobulins, vitamin B12, and a variety of other molecules and ions.

Alkaline Phosphatase↗
PubMed1983

Seven different digoxin immunoassay kits compared with respect to interference by a digoxin-like immunoreactive substance in serum from premature and full-term infants.

Seven different digoxin immunoassay kits showed cross reactivity with an endogenous digoxin-like immunoreactive substance consistently present in serum of neonates, whether premature or full-term. The degree of interference, in decreasing order was: NML greater than New England Nuclear greater than Bio-Rad greater than Clinical Assays greater than Becton Dickinson greater than Serono greater than Syva (EMIT). More recently purchased NML kits showed less sensitivity to the substance, evidently reflecting lot-to-lot differences in antibody. A single baseline determination of the substance before digoxin is administered inadequately compensates for this interference, because the interferent concentrations can differ from day to day, with evidence that it may be most concentrated on the fourth to sixth postnatal day. Its concentration in the serum of neonates is unrelated to the concentration of dehydroepiandrostenedione sulfate, an indicator of fetal adrenal-cortical activity.

Cross Reactions↗
PubMed1982

Falsely negative laboratory diagnosis for myocardial infarction owing to the concurrent presence of macro creatine kinase and macro lactate dehydrogenase.

Macro creatine kinase (CK, EC 2.7.3.2) and macro lactate dehydrogenase (LD, EC 1.1.1.27) were both present in the serum of a 70-year-old woman with myocardial infarction. This interfered with the interpretation of the CK and LD isoenzyme analyses. Gel filtration and immunoprecipitation showed that the macro CK consisted of IgG and CK and the macro LD of IgG and LD. The IgG in this patient bound both MB and BB isoenzymes of CK, resulting in a macro CK complex that co-migrated with CK-MM on cellulose acetate electrophoresis. This situation led to a falsely negative laboratory diagnosis for myocardial infarction.

Aged↗
PubMed1981

Decreased anion gap associated with hypoalbuminemia and polyclonal gammopathy.

Anion gaps were determined in 82 patients with hypoalbuminemia; 24 of these patients had a polyclonal increase in gamma-globulin levels (designated group 5). The 58 patients without the polyclonal increase in gamma-globulin levels were subdivided according to the origin of their serum albumin loss as follows: group 1, renal group 2, gastrointestinal; group 3, skin; and group 4, malignant neoplasms. All groups had a statistically significant reduction in their mean anion gaps when compared with normal control subjects. The greatest decrease was when hypoalbuminemia was accompanied by a polyclonal increase in gamma-globulin levels. Hypoalbuminemia with or without a polyclonal gammopathy is a cause of a low anion gap. No statistically significant correlation was found between the anion gaps and individual serum albumin concentrations.

Acid-Base Equilibrium↗
PubMed1981

Triiodothyronine--binding immunoglobulin in a euthyroid patient.

We describe a clinically euthyroid 60-year old woman with a past history of 1311 therapy for treatment of possible toxic nodular goitre. She had an elevated thyroxine level of 188 microgram/L (normal range 50-125 microgram/L) following her therapy, and her TSH was within normal limits at 4.7 mU/L. However her T3 level, as determined by an RIA technique employing charcoal to separate bound and free T3, was not measurable. T3 added to the patient's serum could not be recovered, therefore the presence of an unusual protein capable of binding T3 was suspected. To avoid this interference, T3 analysis was performed on an ethanol extract of the patient's serum and was found to be 17 microgram/L (normal range 0.8-1.8 microgram/L). At this time her thyroid microsomal antibody titre was 1:100,000. A protein, capable of binding more than 70% of the patient's T3, was demonstrated in the gamma globulin fraction by agarose gel electrophoresis. This protein did not bind T4. Scatchard analysis for T3 binding revealed a protein, presumably IGG, with a binding affinity of 2 x 109 L/mole and binding capacity of 50 microgram/L. This case exemplifies the caution that must be taken in interpreting thyroid function tests. When thyroid hormone levels are inappropriate to the clinical status of the patient the presence of circulating antibodies which can bind the thyroid hormones should be considered.

Alpha-Globulins↗
PubMed1981

Further studies on plasma proteins, lipids, and dye- and drug-binding in a child with analbuminemia.

A previously reported patient with analbuminemia was re-investigated after 4 1/2 years, at age 6. The serum albumin concentration was 150 mg/L by radioimmunoassay. Most of the observed increase in total plasma protein over the 4 1/2 years was attributable to gamma-globulin. Concentrations of total and high-density lipoprotein cholesterol were increased; the esterified:free ratio and the lecithin-cholesterol acyltransferase activity were both normal. Albumin is apparently not essential for binding of lysolecithin generated by the acyltransferase-catalyzed reaction. The binding of bromphenol blue suggested that analbuminemic serum has about 25% of normal binding capacity for bilirubin (more than expected in a patient with analbuminemia), which may explain why newborns with this disorder do not develop kernicterus. Binding by the patient's plasma of diazepam (1020 mg/L) and warfarin (1040 mg/L), which bind primarily to albumin, as well as of propranolol (1.05 g/L), which binds primarily to alpha 1-acid glycoprotein, was also studied. The proportions of free diazepam (14.4%) and warfarin (4.8%) were about 10-fold normal. In contrast, the proportion of propranolol in the free form was decreased (4.5%). Evidently, other plasma proteins are partly compensating for the deficiency of albumin.

Blood Proteins↗
PubMed1975

A possible alternate pathway of bacteriochlorophyll biosynthesis in a mutant of Rhodopseudomonas sphaeroides.

A previously uncharacterized bacteriochlorophyll-less mutant (mutant 8) of Rhodopseudomonas sphaeroides has been found to excrete a tetrapyrrole-protein complex into the incubation medium. The structure of the major pigment of the complex was characterized as 2-desacetyl-2-vinylbacteriopheophorbide. The corresponding magnesium derivative does not fit into the currently proposed biosynthetic pathway for bacteriochlorophyll, and thus may indicate the existence of an alternate pathway of bacteriochlorophyll synthesis in this organism. Such an alternate pathway would be possible if reduction from the chlorin to the tetrahydroporphyrin stage can occur either before or after hydration of the 2-vinyl substituent of chlorophyllide a to an alpha-hydroxyethyl group.

Bacteriochlorophylls↗