PubMed Health⌕ Search

Biomedical subjects

R C Strunk

Publications and source records attributed to R C Strunk.

84 records · Page 5Linked to original sources
PubMed1978

Humoral immunity in experimental hyposplenism.

The immune response to an intravenous bolus of sheep erythrocytes, a large particulate antigen, was examined in weanling Sprague-Dawley rats after varying reduction in spleen size by splenic artery ligation (SAL) or partial amputation (pSx), and the results were compared with splenectomized (Sx) and sham-operated controls. Whereas SAL and pSx rats both produced higher 5 day (primary response) hemolysin antibody titers (P less than 0.001) than Sx rats, levels were lower (P less than 0.05) than in sham-operated rats with larger spleens (P less than 0.001). A similar heterophile pattern was seen in SAL rats at 22 days (secondary response). Within each group there was a positive correlation between splenic weight and serum hemolysin titer (r greater than 0.81) (P less than 0.001). Whereas spleen weight of sham-operated rats increased only 58%, splenic remnants in pSx rats enlarged 139% to 412%, with the greatest percentage of growth in the smallest remnants (25 mg) and the least in the largest remnants (200 mg). These data demonstrate a measurable immunologic advantage of splenic remnants (hyposplenism) over asplenism. This difference, although suboptimal as compared with that of a whole spleen (eusplenism), nonetheless may bolster body defenses to certain forms of bacterial sepsis.

Amputation, Surgical↗
PubMed1977

Harvester ant sensitivity: in vitro and in vivo studies using whole body extracts and venom.

Harvester ant stings by Pogonomyrmex maricopa (Pm) or Pogonomyrmex rugosus (Pr) resulted in serious reactions in 8 patients, 4 with generalized reactions and 1 with large local reactions. Exposure to one species in the genus Pogonomyrmex (P) appeared to cross-sensitize ant-sensitive patients to other species in the same genus as evidenced by skin testing and leukocyte histamine release, but these patients were less sensitive to extracts from other stinging Hymenoptera, including bee, wasp, yellow jacket, hornet, and Formica ant. Pr ant venom was obtained by electrical stimulation of live ants for leukocyte histamine release studies. The venom preparation was considerably more effective in inducing histamine release than a body extract derived from gasters, the posterior abdominal segments. Rabbits immunized with an extract from one species produced precipitating antibodies against the injected extract withich cross-reacted with extracts from other species of harvester ant, but not with other stinging Hymenoptera. Humans and rabbits appear to react to certain genus-specific antigens present in Pogonomyrmex whole body extracts. Proper identification of the offending ant is crucial for proper testing and treatment of ant-sensitive patients.

Animals↗
PubMed1977

Intrapatient variability in theophylline kinetics.

Seven asthmatic children had repeat determinations of theophylline pharmacokinetic measurements over three- to nine-month intervals. Significant intrapatient variability was found in the theophylline clearance and t1/2, which determine the dosage regimen necessary to provide given average, peak, and trough theophylline plasma levels. Repeat clearance values were, on average, 52% different from the original clearances, with a range of -57% to +142%. A single determination of theophylline kinetic measurements in any individual patient cannot be used routinely to predict future theophylline dosage regimens for that patient.

Adolescent↗
PubMed1977

Herpes simplex virus infections in guinea pigs deficient in the fourth component of complement.

Separate groups of normal and C4-deficient guinea pigs were inoculated with herpes simplex virus by intradermal (i.d.) and intraperitoneal (i.p.) routes. Virus infection, confirmed by clinical, virological, and serological criteria, did not last longer and was not more severe in C4-deficient guinea pigs than in normal guinea pigs. Serum C component levels were measured before, during, and after herpes simplex virus infection. In normal gruinea pigs there was no evidence for C4 utilization after either i.d. or i.p. inoculation. In both normal and C4-deficient guinea pigs, C1 and C3-9 levels remained unchanged in spite of i.d. or i.p. infection. These data suggested that C4 and the classical C pathway were not important for virus clearance.

Animals↗
PubMed1977

Serum complement depression during viral lower respiratory tract illness in cystic fibrosis.

Cystic fibrosis (CF) patients with viral lower respiratory tract illnesses (LRI) had depressed levels of the third and fourth components of complement, which returned to normal after recovery. There was no clinical evidence of immune complex disease. CF patients with LRI and no virus isolates, CF patients in stable status, and non-CF patients with LRI did not have complement depression. It is postulated that antigen-antibody complex activation of complement may occur in CF patients with viral LRI.

Adolescent↗
PubMed1977

Complement activation and group B streptococcal infection in the newborn: similarities to endotoxin shock.

Serial measurements of CH50, C3, C4, and factor B were performed on three newborn infants with group B streptococcal sepsis. Two of the septic infants had a colonized but noninfected identical twin. All three infants with group B streptococcal sepsis had hypotension, prolonged coagulation times, neutropenia, and respiratory failure. During the course of the sepsis, factor B was depressed 30% to 35%, C3 was depressed 40% to 60%, and CH50 was depressed by 100% when compared to their cord blood levels. Two of the infants also had a 50% to 70% depression of C4. In contrast, no significant decrease in complement levels occurred in the siblings of the twins or in two additional control infants. These data are characteristic of older patients with Gram-negative sepsis and strongly suggest that the group B Streptococcus has endotoxin-like properties.

Adult↗
PubMed1975

Complement biosynthesis in vitro by rat hepatoma cell strains.

Four separate rat hepatoma strains were examined for their capacity to synthesize complement (C). None of the strains synthesized detectable amounts of the first components (C-1), and only one strain (7800C-1) produced the fourth component (C4). However, each of the strains synthesized significant amounts of biologically active C-2 and C-3. Three of the four strains also produced C-5 and the natural inhibitor of C-1 (C1 INH). Two control rat cell strains (fibroblast and pituitary) did not synthesize any detectable C components. Production of C, studied extensively in 7800C-1 and H-4, was reversibly inhibited by cycloheximide (2 mug/ml) and [ 14-C ] amino acids were incorporated into C-2, C-3, and C-1 INH. As assessed by gel filtration, the elution positions of the C components synthesized by the cells in culture were similar to those of the corresponding proteins in normal rat serum. Hydrocortisone (10-6 to 10-7 M) stimulated the production of C-3 by H-4 but C-2 and C-5 production were not affected. These C-producing hepatoma cells may prove useful for studies of the control of C biosynthesis.

Animals↗
PubMedDate not supplied

Deaths from asthma in childhood: can they be predicted?

We have used a case-controlled study to clarify positive, as well as negative, clinical characteristics of children who die with asthma. Variables discriminating between 21 patients who died from asthma and 21 asthmatic control cases matched for age, sex, and severity of illness were: 1) seizures with asthma attacks (p less than 0.01); 2) large reductions in prednisone dose (p less than 0.01); 3) disregard of wheezing (p less than 0.06); 4) increased asthma in the week before discharge (p less than 0.05); 5) poor self-care (p less than 0.01); 6) parent/staff conflict (p less than 0.01); 7) depressive symptoms (p less than 0.05); 8) use of inhaled beclomethasone (p less than 0.05); 9) patient/staff conflict (p less than 0.01); 10) patient/parent conflict (p less than 0.05); 11) manipulative use of asthma (p less than 0.01); 12) emotional disturbance (p less than 0.01); 13) history of reaction to separation or loss (p less than 0.01); and 14) family dysfunction (p less than 0.05). Most of the clinical characteristics previously thought to place patients at greater risk for a fatal asthmatic attack were equally frequent in the children who died and the control cases. This study indicates that psychological risk factors were prominent in severely asthmatic children who subsequently died of asthma.

Age Factors↗