Biomedical subjects
Publications and source records attributed to D C Anderson.
We studied 136 patients without focal neurologic findings by EEG and computed tomographic (CT) scanning. Six patients (4.4%) had focal CT lesions. All six had abnormal EEGs, and in four the EEG findings were focal. The initial complaint did not influence the yield of focal CT lesions. The findings suggest that neurologic examination and EEG can be used to screen for focal CT abnormalities.
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A simple method has been developed using 'SEP-PAK' disposable silica cartridges to separate the major endogenous vitamin D metabolites, namely vitamin D3, 25-hydroxy vitamin D3 (25OHD3), 1,25 dihydroxy vitamin D3 (1.25 (OH)2D3) and 24,25 dihydroxyvitamin D3 (24,25 (OH) 2D3). After extraction of plasma in isopropanol-toluene (25:75) the dried extract is reconstituted in hexane; this is applied to a SEP-PAK column, and stepwise elution carried out under gravity with 0.1 divided by isopropanol in hexane (neutral lipids), 1% isopropanol in hexane (D3), 3 divided by isopropanol in hexane (25OHD3), 3.125 divided by ethanol in dichloromethane (24,25 (OH) 2D3) and 50 divided ethanol in toluene (1, 25(OH) 2D3). Complete separation of these D3 metabolites is achieved by this process and up to 40 samples can be handled at one time. If combined with a suitable ligand binding assay, the system appears to be suitable for preparation of samples prior to the routine assay of vitamin D metabolites.
Indirect immunofluorescent (IIF) techniques employing antitutulin and anticentrosome antibodies were modified for studies of migrating polymorphonuclear (PMNs) leukocytes exposed to gradients or uniform concentrations of chemotactic factor (CF). No significant changes in microtubule (MT) number per cell occurred with chemotactic activation. Significant increases in average MT length per cell occurred upon exposure to gradients or uniform concentrations of CFs. Elongation of MT parallel to the direction of cell migration occurred coincident with shortening of other sets of MTs perpendicular to the direction of cell migration. MT extended radially from a single microtubule organizing center (MTOC) in greater than 99.9% of cells. Following chemotactic activation, the location of the MTOC was observed between nuclear lobes in 65% of fully polarized cells, "posterior" to the nucleus in congruent to 34% and "anterior" in less than 1%. Thus alterations of MT array occur coincident with cell orientation or migration in response to chemotactic stimuli.
Adrenal steroidogenesis has been studied in vivo in eleven patients aged 13-68 years with 21-hydroxylase deficiency, in one patient with 11 beta-hydroxylase deficiency and in ten female control subjects. Serum levels of the delta 5 3 beta-hydroxysteroids, pregnenolone (Pe), 17 alpha-hydroxypregnenolone (17Pe), dehydroepiandrosterone (DHEA) and androstenediol (Adiol) and their delta 4 3-keto counterparts, progesterone (Po), 17 alpha-hydroxyprogesterone (17Po) androstenedione (Adione) and testosterone as well as of 11-deoxycortisol and cortisol were measured during acute adrenal suppression with dexamethasone followed by stimulation with synthetic 1-24 ACTH. In the seven patients with 21-hydroxylase deficiency who were on adequate glucocorticoid therapy, grossly exaggerated responses of 17Po and Po to ACTH were nevertheless preserved. In contrast, there was a grossly subnormal response of 17Pe, DHEA and Adiol to ACTH, and low basal levels of DHEA-sulphate. In the untreated patients the response of 17Pe and DHEA was normal. The Adione response was exaggerated in untreated and normal in treated cases. Similar findings obtained in the patient with 11 beta-hydroxylase deficiency who was studied after 6 weeks without replacement therapy. Our findings demonstrate that production of adrenal steroids that are associated with the adrenarche is not exaggerated in untreated CAH, and is grossly suppressed in treated cases. These findings are compatible with the hypothesis that intra-adrenal cortisol may initiate and/or maintain production of the delta 5 steroids by the zona reticularis that occurs in the human adrenarche.
The relative roles of serum factors required for opsonization of type XIV Streptococcus pneumoniae were investigated by means of luminol-enhanced chemiluminescence (CL), bactericidal, and immunofluorescence assays employing adult sera containing high (>1,000 ng of antibody nitrogen per ml) or low (<200 ng of antibody nitrogen per ml) antibody concentrations as determined by radioimmunoassay. Specific antibody concentration correlated directly with both total and heat-labile CL activity (P < 0.005) and with the bactericidal index (P < 0.05) at a serum concentration of 10%. The importance of specific antibody as an opsonin was confirmed by the abolition of CL activity and immunoglobulin immunofluorescence observed after absorption of heated sera with type XIV pneumococcal cells and by the dose response in CL and bactericidal activity observed with the addition of immunoglobulin G to hypogammaglobulinemic serum. A role for the classical complement pathway in opsonization was indicated by significantly greater CL integrals for high-antibody sera than for low-antibody sera depleted of factor D and by the bactericidal activity noted for untreated, but not magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid-chelated low-antibody sera. The alternative pathway contributed more than half of the CL activity of both high- and low-antibody sera. However, after magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid chelation, only sera with high antibody concentrations or agammaglobulinemic serum reconstituted with immunoglobulin G with high specific antibody levels supported significant bactericidal activity. Therefore, type-specific antibody and complement promote opsonization of type XIV S. pneumoniae, and this may occur via either complement pathway. These results suggest that CL is a suitable tool to delineate serum factors and their contribution to opsonization, but results must be related to other functional assays.
A progesterone monoclonal antibody which may be used in the development of a sensitive and specific immunoassay is described. The preparation involved isolation of spleen cells from Balb/c mice immunized with progesterone 11 alpha-hemisuccinate-bovine serum albumin conjugate, which were then fused with two different mouse myeloma cell lines. Hybridomas secreting antibody to progesterone were detected by immunoassay and cloned in soft agar. Five percent of the resulting clones secreted antibody; these clones originated from cultures producing very little antibody, and so might easily have been discarded. THe monoclonal antibody obtained is highly specific and has a binding affinity of approximately 1.7 X 10(9) M-1, so it may be advantageously used in the detection of progesterone in body fluids.
The recent availability of two-dimensional echocardiography (2DE) has fostered the expectation that cardiac embolic sources could be identified or excluded with certitude in ischemic stroke patients. As a screening procedure, 2DE has had a low yield. In selected patients, 2DE holds promise as a useful diagnostic test. Stroke patients who may benefit from 2DE include patients under age 45, patients with suspected left atrial myxoma, and patients with known infective endocarditis, prosthetic heart valves, or rheumatic valvular heart disease. In patients with ischemic heart disease, the yield of useful information from 2DE will be low but may, on occasion, influence management.
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Four families with familial hypocalciuric hypercalcaemia were studied. The probands presented with abdominal pain, which in three was due to acute pancreatitis; in two the condition was life threatening. Serum concentrations of calcium, magnesium, phosphate, and immunoassayable parathyroid hormone, urinary calcium excretion, and the rate of renal tubular reabsorption of phosphate were measured; the findings were compared with results in 10 patients with primary hyperparathyroidism matched for serum calcium concentration to establish differences between the diseases. Familial hypocalciuric hypercalcaemia should be suspected in patients with hypercalcaemia in whom daily urinary calcium excretion is below 5 mmol (200 mg) provided renal insufficiency, vitamin D deficiency, and ingestion of drugs that reduce calcium excretion have been excluded. Most cases appear to run a benign course, but some may suffer considerable morbidity. Surgical treatment should be reserved for patients with severe complications, when all parathyroid tissue should be removed.
The serum pharmacokinetics and CSF penetration of moxalactam were determined in 39 children with bacterial meningitis. The mean serum concentrations 30 minutes after a 37.5 or 50 mg/kg dose were 66.7 and 113 micrograms/ml, respectively. The t 1/2 beta was between 1.8 and 2.0 hours. The mean +/- 1 SD CSF/serum percentage was 18.5 +/- 16.0% (range 2.0 to 61%) for all children on any day of therapy or hour, after the last of three 50 mg/kg doses. Cerebrospinal fluid bactericidal titers were greater than or equal to 1:32 in 13 of 14 CSF specimens. Moxalactam adequately penetrates into the CSF of children with bacterial meningitis after repetitive 50 mg/kg doses.
Neutrophil function was investigated in a male child with glycogenosis type Ib who demonstrated susceptibility to staphylococcal infections and neutropenia. Random motility and directed migration of the patient's neutrophils in vitro were profoundly diminished. The patient's neutrophils stimulated in suspension with chemotactic factors (CFs) generated chemiluminescence that was comparable to or greater than that generated by neutrophils from controls, but the patient's neutrophils failed to assume a normal bipolar configuration in response to chemotactic stimuli. They also failed to demonstrate enhanced adherence after a single exposure to CFs or decreased adherence after sequential exposures to increasing concentrations of CFs. Unlike neutrophils from controls, the patient's neutrophils failed to redistribute surface adhesion sites from lamellipodia (anterior pole) to uropods (tail) after sequential CF stimuli. These findings indicate a functional link between CF-induced configurational changes and altered adhesiveness of neutrophils under conditions of directed locomotion and suggest that a redistribution of surface adhesion sites is related to the mechanism of neutrophil locomotion.
Pontiac fever, a unique epidemiologic form of legionellosis, is characterized by a short (one- to two-day) incubation period and a self-limited grippe-like illness without pneumonia. In 1968, the first documented outbreak of this syndrome affected persons who had entered a health department building in Pontiac, Michigan. Epidemiologic analyses clearly implicated as airborne agent and suggested that evaporative condenser water aerosols being disseminated by a defective air conditioning system played a key role in the outbreak. Guinea pigs that were exposed in the building and to laboratory aerosols of evaporative condenser water developed bronchopneumonia. Legionella pneumophilia (serogroup 1) was isolated from the exposed guinea pigs' lungs. Paired acute and convalescent serum specimens from 37 patients were tested by the indirect fluorescent antibody technique using L. pneumophila serogroup 1 antigen, and 31 (84%) had rises in titer from less than 32 to greater than or equal to 64.
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