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Biomedical subjects

C W Smith

Publications and source records attributed to C W Smith.

At least 325 records · Page 18Linked to original sources

Leukocyte LFA-1, OKM1, p150,95 deficiency syndrome: functional and biosynthetic studies of three kindreds.

Three patients (2 female, 1 male) with recurrent infection, granulocytosis, impaired pus formation, and/or delayed umbilical cord separation were identified. Assessments of polymorphonuclear leukocytes (PMN)/monocyte function in each patient revealed profound abnormalities of adherence and adherence-dependent functions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of their PMN lysates demonstrated a deficient or absent protein(s) of 138 kilodaltons (gp 138). Na3HB4 labeling demonstrated the absence of a major cell surface glycoprotein complex in each patient. Among parental and sibling PMN suspensions, functional assessments revealed no consistent abnormalities, although variably diminished gp138 was identified by SDS-PAGE and Na3HB4 labeling. Analysis by fluorescence-activated cell sorting and monoclonal antibodies (MAb) to LFA-1 alpha, OKM1 alpha, and their common beta subunit demonstrated a severe or total deficiency of PMN/monocyte surface expression of each protein among all patients; intermediate values were observed for parental and affected sibling suspensions, findings consistent with an autosomal recessive mode of inheritance for this disorder. Cell surface labeling (125I) and immunoprecipitation with the same MAb demonstrated the absence of these glycoproteins in addition to a 150-kilodalton protein (p150,95). Identical abnormalities of surface expression of patient lymphocytes blast-transformed with phytohemagglutinin (PHA) or Epstein-Barr virus were demonstrated. Further, significantly diminished natural killer cell cytotoxicity was observed for each patient tested. PHA blast-transformed patient lymphocytes labeled with [35S]methionine demonstrated a total absence of the beta molecule but indicated the presence of an LFA-1 alpha precursor. These findings indicate that LFA-1 alpha synthesis and surface expression require beta association. It is concluded that impaired inflammatory function in this disorder is casually related to a heritable deficiency of critical "adhesive" leukocyte glycoproteins.

Adolescent↗

Bovine neutrophils treated with chemotactic agents: morphologic changes.

Neutrophils were isolated from the peripheral blood of cattle. After the neutrophils were incubated with zymosan-activated serum, the neutrophils changed from spherical to a bipolar shape. Ninety percent of the neutrophils became bipolar in 5 to 10 minutes. Bacterial cell filtrate and casein also induced bipolar shape changes in neutrophils, but N-formyl-L-methionyl-L-leucinyl-L-phenylalanine did not. The neutrophil-shape-change response was a rapid in vitro assay to evaluate early chemotactic events.

Animals↗

Cardiopulmonary effects of an intravenous infusion of guaifenesin, ketamine, and xylazine in dogs.

A 5% solution of dextrose in water containing 50 mg of guaifenesin, 0.25 mg of xylazine, and 1 mg of ketamine/ml was infused IV at the rate of 2.2 ml X kg-1 X hour-1 in dogs. Heart rate, systemic vascular resistance, mean arterial blood pressure, rate-pressure product, and arterial oxygen tension were not altered significantly from baseline values during 2 hours of anesthesia. Cardiac index was significantly (P less than 0.05) decreased from base-line values. Hypoventilation resulted in increased arterial carbon dioxide tension and decreased arterial pH. After the dogs were given glycopyrrolate, cardiac index returned to base line, and heart rate, mean arterial pressure, and rate-pressure product were significantly greater (P less than 0.05) than base-line values.

Anesthesia, General↗

Neutrophil function in the dog: shape change and response to a synthetic tripeptide.

Isolated dog neutrophils exposed to known chemotactic factors assumed a bipolar configuration in suspension. This response was initiated within 2 minutes with a gradual return to spherical shape. The rate of return to sphere was positively correlated with the dose of stimulant. Dog neutrophils exposed to N-formylmethionyl-leucyl-phenylalanine (fMLP) did not adapt to bipolar conformation and did not bind radiolabeled fMLP. These findings are consistent with other species (pig and cow) that also did not respond to fMLP.

Animals↗

A conformationally constrained vasopressin analog with antidiuretic antagonistic activity.

Application of information derived from a three-dimensional model of vasopressin bound to its antidiuretic receptor resulted in the design and synthesis of a bicyclic vasopressin analog, [5,8-cyclo(1-beta-mercaptopropionic acid,2-phenylalanine,5-aspartic acid,8-lysine)]vasopressin. The analog acts as an antagonist of the antidiuretic activity of vasopressin.

Animals↗

Impaired motility of neonatal PMN leukocytes: relationship to abnormalities of cell orientation and assembly of microtubules in chemotactic gradients.

To allow a further understanding of the pathogenesis of impaired stimulated locomotion by polymorphonuclear leukocytes (PMNs) in human neonates, we studied cellular orientation by neonatal PMNs in response to well-defined chemotactic gradients (Zigmond orientation chambers) and characterized the cytoplasmic microtubule (MT) complex of neonatal PMNs during cell orientation and movement. PMN suspensions obtained from 52 neonates demonstrated a diminished capacity to undergo orientation at all time intervals after exposure to gradients of N-formyl-methionyl-leucyl phenylalanine (f-Met-Leu-Phe) or C5a. Among responding (orienting) neonatal PMNs observed, only 70% (f-Met-Leu-Phe) or 59% (C5a) oriented accurately (toward chemotactic gradients) as compared to values of 96% (f-Met-Leu-Phe) or 92% (C5a) for adult controls. Furthermore, neonatal PMNs failed to alter their direction of orientation/migration when chemotactic gradients were reversed. Similar abnormalities were observed when 10-fold gradients of f-Met-Leu-Phe were employed over a concentration range between 10(-7) and 10(-11) M. Employing tubulin immunofluorescence, the cytoplasmic MT complex of-neonatal PMNs was assessed prior to and after cell exposure to uniform concentrations or gradients of chemotactic factors (CFs). MT assembly by neonatal PMNs studied under these experimental conditions was significantly diminished. Neonatal cell suspensions demonstrated 26 +/- 5 (f-Met-Leu-Phe) or 27 +/- 6 (C5a) MT/cell as compared to respective values of 36 +/- 6 or 35 +/- 5 for adult suspensions (P less than .001). MT lengths of neonatal PMNs increased from 6.7 +/- 1 micron (PBS) to 7.5 +/- 1 micron (f-Met-Leu-Phe) or 7.3 +/- 1 micron (C5a) as compared to values of 6.5 +/- 1 micron (PBS), 11.1 +/- 1 micron (f-Met-Leu-Phe), and 10.9 +/- 1 micron (C5a) for adult PMNs exposed to gradients or uniform concentrations of CFs (P less than .01 for both f-Met-Leu-Phe and C5a). Thus, the polymerized tubulin mass product of chemotactically stimulated neonatal PMNs (202 micron) was significantly (P less than .001) diminished as compared to adult PMNs (360 micron). As shown by a [3H]colchicine binding assay, impaired MT assembly could not be attributed to diminished cytoplasmic tubulin content of neonatal PMNs, which was comparable to adult PMNs.

Chemotaxis, Leukocyte↗

Purification and properties of Ca2+-regulated thin filaments and F-actin from sheep aorta smooth muscle.

We have investigated the conditions for isolation of Ca2+-regulated thin filaments from sheep aorta. Inhibition of proteolysis by 2 micrograms ml-1 leupeptin and chymostatin and of oxidation with 5 mM dithiothreitol were essential. Washed homogenates were extracted in 10 mM ATP of low ionic strength at pH 6.1 to minimize coextraction of myosin with thin filaments. Thin filaments were separated from myosin by high speed sedimentation; 20% glycol was added to prevent loss of regulatory factors and tropomyosin. The resulting thin filaments (yield 2.5 mg protein g-1 artery wet weight) were made up of actin, tropomyosin and a 120 000 Mr protein (molar ratio 1:1/5:1/29) and were up to 4 micron long. They activated skeletal muscle myosin at least 50 times in presence of Ca2+. Up to 80% inhibition was observed in the absence of Ca2+. We also prepared pure arterial F-actin, which activated skeletal myosin more than the thin filaments, but was similar to skeletal F-actin. We conclude that Ca2+ regulation is negative, involves cooperative interactions between actin, myosin and tropomyosin and suggest that it is mediated by the 120 000 Mr protein.

Actins↗

Late-onset tibia vara: a comparative analysis.

We reviewed the clinical and radiographic characteristics and response to treatment of 11 children (16 knees) with idiopathic late-onset tibia vara (adolescent Blount's disease) followed for an average of 5.7 years (range, 3-10 years). The clinical characteristics were very consistent: black race; 2:1 male predominance; normal height; marked obesity; knee pain as the primary presenting complaint; and slowly progressive genu varum deformity that averaged 19 degrees (range, 10-45 degrees). Radiographically, the epiphyses were wedge shaped owing to medial flattening, the physes were irregular in thickness, and there was minimal, if any increased prominence of the proximal medial metaphysis. Nineteen proximal tibial valgus and diaphyseal fibula osteotomies were performed on 15 knees. There was a 50% rate of recurrent deformity in males with clinical onset at less than or equal to 10 years of age. Females and older males had no recurrences. Histopathologic studies of the physis performed on one case demonstrated abnormal cellular islands of hyaline cartilage, small foci of necrotic cartilage, prominent intertrabecular vascularity, and premature medial physeal closure. These data support late-onset tibia vara as a distinct entity closely related to the infantile form. They also suggest three specific forms of tibia vara based on the age at clinical onset: infantile (0-3 years), juvenile (4-10 years), and true adolescent (11 years or older). The juvenile group is characterized by a high rate of recurrence following surgical correction, whereas the others are not.

Adolescent↗

Ceftriaxone levels in blood and tissue during cardiopulmonary bypass surgery.

One gram of ceftriaxone was given intravenously to 15 patients approximately 2 h before cardiopulmonary bypass surgery. Ceftriaxone levels in plasma (mean +/- standard deviation) were 60.4 +/- 18.8 micrograms/ml (range, 17.0 to 96.0 micrograms/ml) at the beginning of bypass, 44.2 +/- 16.6 micrograms/ml (range, 9.4 to 78.6 micrograms/ml) at the end of bypass, and 19.6 +/- 9.6 micrograms/ml (range, 4.2 to 47.1 micrograms/ml) the following morning, 18.1 to 24.7 h after infusion of ceftriaxone. Concentrations in the sternal bone were 4.7 +/- 2.1 micrograms/g (range, 1.0 to 10.1 micrograms/g; tissue-to-plasma ratios, 0.066 +/- 0.036). Concentrations in the atrial appendage were 7.7 +/- 1.8 microgram/g (range, 3.6 to 10.2 micrograms/g; tissue-to-plasma ratios, 0.143 +/- 0.062). These data suggest that a single dose of ceftriaxone might be useful for prevention of infection due to susceptible pathogens.

Aged↗

Evaluation of left ventricular performance using digital subtraction angiography.

Cardiac applications for digital subtraction angiography appear promising, but few correlative studies with contrast ventriculography have been done. Left ventricular volume, ejection fraction, and regional wall motion by digital subtraction angiography were evaluated after intravenous injection of 40 ml of iodinated contrast medium and after left ventricular injection of 5 to 10 ml of contrast medium. A film-based system of the authors' own design was used. Results were compared with those after direct left ventricular injection of 40 ml of contrast medium. The ventriculograms after intravenous injection were of diagnostic quality in 9 of 12 studies, and there were close correlations between intravenous and direct-injection studies for left ventricular ejection fraction (r = 0.89, n = 9, and p = 0.001) and for left ventricular volume (r = 0.91, n = 18, and p less than 0.001). Regional wall motion scores showed close correspondence in 83% of sectors. After small-volume left ventricular injections, the ventricular image was enhanced considerably by digital subtraction. Correlations between small- and large-volume ventriculograms were close for left ventricular ejection fraction (r = 0.91, n = 8, and p = 0.002) and for left ventricular volume (r = 0.96, n = 16, and p less than 0.001). There was close correspondence of wall motion scores in 87% of sectors. Thus, digital subtraction angiography improves the visibility of the left ventricle after either intravenous or small-volume direct left ventricular injection. Digital images produce excellent estimates of left ventricular volume and should have considerable usefulness for the study of cardiac performance and anatomy.

Adult↗

Treatment of cancer of the cervix with a high-dose-rate afterloading machine (the Cathetron).

Two hundred and ninety-one patients with invasive carcinoma of the cervix uteri were treated by a combination of external beam therapy (telecobalt or 4 Mv Linear accelerator) and a high dose-rate afterloading intracavitary apparatus (the Cathetron). All patients have been followed for a minimum of 3 1/2 years. The five year survival rates are: all patients 55%; Stage I, 81%; Stage IIA, 74%; Stage IIB, 40%; Stage III, 27%. Death was directly attributed to treatment in five patients. We found a serious complication rate of 3% for all patients treated, the major problem being radiation ileitis. It is concluded that high dose-rate treatment offers comparable results to conventional radium therapy; the choice between high and lose dose-rate afterloading systems depends on the number of patients needing treatment and associated economic factors rather than any intrinsic radiobiological advantage of either system.

Adenocarcinoma↗