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Biomedical subjects

R Caldwell

Publications and source records attributed to R Caldwell.

36 records · Page 2Linked to original sources
PubMed1984

Albumin influences sulfobromophthalein transport by hepatocytes of each acinar zone.

To determine whether profiles of decreasing concentration were generated among hepatocytes of the liver acinus during the transport of sulfobromophthalein sodium (BSP), rat livers were perfused with various concentrations of this dye (10 microM to 1 mM) in the presence and absence of albumin. After steady-state conditions for the biliary secretion of BSP had been attained, pieces of liver were rapidly frozen. Following the alkalinization of cryostat-cut sections, the relative concentration of BSP in hepatocytes of each zone and the effect of albumin on this localization were quantitated by microspectrophotometry. The results showed that BSP, perfused in the absence of albumin, was efficiently extracted by the liver (95% on a single pass), generating distinct profiles of decreasing cellular concentration from zone 1 to zone 3 at every concentration of BSP. However, the addition of albumin to the perfusate greatly reduced the extraction of BSP from the sinusoidal compartment and resulted in the abolition of the differences in BSP content between hepatocytes of zone 1 and zone 3. These results represent a direct demonstration that, as predicted by mathematical modeling, binding of BSP to albumin indeed results in a more homogeneous distribution of BSP within the liver acinus. A simple and direct microspectrophotometric method is therefore available to follow the changes in the relative concentration of BSP among the hepatocytes of the various acinar zones.

Animals↗
PubMed1984

Acute trazodone poisoning: clinical signs and plasma concentrations.

A total of 70 patients presenting with suspected acute trazodone poisoning were notified to the Poisons Unit (National Poisons Information Service for England) from August 1980 until March 1983. Detailed follow-up information was obtained on 41 patients, 22 of whom were thought to have ingested trazodone alone. In these latter patients drowsiness (11), ataxia (5), nausea/vomiting (4) and dry mouth (2) were the manifestations of toxicity reported most frequently, only 2 patients became unconscious (grade 2 or 3 coma), and all recovered uneventfully with no more than minimal supportive therapy. The presence of trazodone was confirmed in 8 out of 9 patients from whom specimens (blood and urine) were received. The highest plasma trazodone concentrations (15 and 19 mg/l, respectively) were both associated with only drowsiness and ataxia. However, in 2 further patients moderate plasma trazodone concentrations (4.2 and 8.2 mg/l, respectively) were associated with deep (grade 3-4) coma, although 1 of these latter patients had also ingested ethanol (plasma concentration 3.0 g/l). Although acute trazodone poisoning does not appear to be associated with cardiac arrhythmias or convulsions, these results emphasise that drowsiness and ataxia are commonly encountered, while coma may occur in severe cases. The possible contribution of metabolites of trazodone to toxicity and the potentiating effect of co-ingested drugs or alcohol must be remembered.

Adolescent↗
PubMed1983

Toxicological investigations in the detection of drug-induced disease in elderly patients.

1 During 1978--1980 general toxicological investigations were performed on specimens from 211 patients (62 male, 149 female) aged 65 years and over. 2 The investigations were an important factor in establishing the diagnosis in 32 of 91 (28 male, 63 female aged 65--92 years, median 73 years) poisoned patients, most (75) of whom had deliberately taken overdoses. 3 Seventy-one patients were severely poisoned (grade 3--4 coma) and 10 died. Benzodiazepines (49%) and barbiturates (43%) were the drugs encountered most frequently, although 54% had ingested more than one pharmaceutical preparation. 4 In the survivors the depth of coma was usually greatest in patients poisoned principally with barbiturates, whilst the duration of coma and the incidence of respiratory complications were greater in those poisoned with benzodiazepines. However, there was considerable variability in the depth and duration of coma associated with a given initial plasma concentration within both groups. 5 Although general toxicological investigations can provide useful diagnostic information when poisoning is suspected in elderly patients, unequivocal interpretation of the results obtained is not always possible.

Aged↗
PubMed1981

Spondylocostal dysostosis associated with anal and urogenital anomalies in a Mennonite sibship.

Spondylocostal dysostosis, anal atresia, and urogenital anomalies were observed in two male infants of a consanguineous Mennonite couple. A careful review of previously reported syndromes of severe vertebral abnormalities and/or imperforate anus suggests that our patients have a previously undescribed recessive disorder that should be included in the differential diagnosis of rib and vertebral anomaly syndromes.

Anus, Imperforate↗
PubMed1980

Improved results in newborns undergoing coarctation repair.

Among 172 children who underwent repair of coarctation of the thoracic aorta from June 1, 1967, to June 1, 1979, there were 50 who were less than 6 weeks old. A review was undertaken to assess mortality and postoperative residual hypertension in this newborn age group. Forty-five (90%) had one or more associated congenital cardiac lesions, which were repaired or paliated at the time of coarctation repair. The three most common associated lesions were patent ductus arteriosus (74%), atrial septal defect (74%), and ventricular septal defect (62%). Thirty-one newborns underwent resection with parimary end-to-end repair with 8 deaths (26%), and 18 underwent Dacron patch angioplasty and 1 underwent subclavian angioplasty with 4 deaths (21%). Of the 38 survivors, 36 (95%) had good pedal pulses on postoperative clinical examination 3 months to eleven years postoperatively. Seventeen (45%) had upper and lower extremity blood pressure measured; 2 (5%) showed residual upper extremity hypertension (greater than 2 standard deviations above the mean and a gradient less than 20 mm Hg). One of these 2 patients has undergone repeat repair. Based on this low mortality and infrequent need for repeat repair, we advocate aggressive early operation and judicious use of palliative procedures in newborns, when indicated, for associated defects.

Aorta, Thoracic↗
PubMed1978

Divalent cation stimulation of in vitro fibre assembly from epidermal keratin protein.

Keratin was extracted from purified cornified cells of newborn rats in Tris-HCl-buffered 8 M urea containing beta-mercaptoethanol. Microfilaments were assembled in vitro by reducing the ionic strength of buffer and the urea concentration. One millimolar concentration of KCl and NaCl did not affect filament formation, but the same concentration of divalent cations greatly altered this process. CaCl2 and MgCl2 induced gelation of keratin by formation of bundles of birefringent macrofilaments. ZnCl2, CuSO4 and HgCl2 formed greater numbers of macrofilaments and the protein aggregated.

Amino Acids↗
PubMed1978

Activity of alpha-1, 4-glucosidase in furazolidone-induced glycogenosis.

Furazolidone (FZ) at 700 and 800 p.p.m. was added to feed mixtures fed turkey poults two and three weeks posthatching, respectively, to induce acute experimental cardiomyopathy. Poults in the control pen received the same ration but without FZ. From EKG data obtained at 2, 4, and 5 weeks of age, control unaffected and experimental affected poults were selected for sacrifice. Poults were sacrificed by cervical dislocation and appropriate samples of hepatic tissue were removed for assays of activity of alpha-1, 4-glucosidase. Results indicate that enzyme activity in affected FZ-treated poults is similar to that in unaffected control poults. Lack of significant differences in activity of this lysosomal enzyme suggests that FZ-induced glycogenosis may be related to the adult form of idiopathic generalized glucogenosis, the etiology of which remains unidentified.

Animals↗
PubMed1973

Effects of promethazine-hydrochloride on human polymorphonuclear leukocytes.

Promethazine hydrochloride at a concentration of 0.033 mg/ml has pronounced effects on leukocyte metabolism and function. The drug inhibits the phagocytosis-induced increases in O(2) consumption and hexose monophosphate shunt activity. Associated with these effects is an inhibition of the iodination of zymosan particles and an inhibition of bacterial killing by the cell. At least two mechanisms appear to be involved. Many of the effects can be explained by an inhibition of phagocytosis, but promethazine also inhibits the decarboxylation of amino acids and iodide fixation in a cell-free system, indicating a specific effect on metabolism. These results may partially account for the action of the drug in ameliorating the effects of erythroblastosis.

Cell Nucleus↗
PubMedDate not supplied

Dynamic three-dimensional echocardiographic reconstruction of congenital cardiac septation defects.

Dynamic three-dimensional echocardiographic reconstructions of 27 cardiac septation defects were performed in 19 sedated infants and children. Using a subxiphoid rotational scanning approach, complete visualization of the entire shape and breadth of the defect was attained in 11 of 16 ventricular septal defects and 9 of 11 atrial septal defects. This technique enabled the operator to cut slices from the three-dimensional block of echocardiographic data in order to present septation defects in a region- or lesion-oriented fashion. Poor baseline two-dimensional image quality and certain small septation defects that were readily obscured by nearby structures led to inadequate three-dimensional reconstructions. The application of dynamic three-dimensional echocardiography for assessment of cardiac septation defects uniquely provided (1) the ability to present en face views of atrial and ventricular septal defects; and (2) a means by which intracardiac anatomy can be displayed in a region- and lesion-oriented fashion for interventional and surgical planning purposes.

Adolescent↗
PubMedDate not supplied

Recall Rummy: learning can be fun.

BACKGROUND: Nurse educators are continuously seeking creative methods to teach nursing skills. Continuing education programs have adapted and used television game show themes as effective teaching strategies. METHOD: The traditional card game of rummy has been modified into a creative learning technique for entertaining and reinforcing skill techniques for nurses practicing in a clinical setting. CONCLUSION: Imagination and creativity are important assets for planning and teaching skills that relate to the practice of nursing. Recall Rummy presents one such approach to teaching nursing skills.

Clinical Competence↗
PubMedDate not supplied

Echocardiographic analysis of rejection in the infant heart transplant recipient.

Eleven children who received transplants at less than 2 years of age underwent 59 echocardiograms at the time of endomyocardial biopsy for the assessment of the ability of echocardiography to predict acute rejection in the infant heart transplant recipient. Two patients died of acute rejection and autopsy findings were compared with premortum echocardiograms. Biopsy specimens were graded as no rejection (n = 46), mild rejection (cellular infiltrate, n = 5), or moderate-severe rejection (myocyte necrosis/edema, n = 8). Echocardiographic indexes measured included the following: left ventricular mass, left ventricular volume, ejection fraction, heart rate, and peak rate of posterior wall thinning. Compared with controls, patients during mild rejection had slower posterior wall diastolic thinning (p < 0.01). No significant change was noted in left ventricular mass until endomyocardial biopsy specimens showed severe rejection. No significant changes were noted in heart rate or ejection fraction in any of the groups. In conclusion, decrease in the peak rate of posterior wall diastolic thinning may be a sensitive indicator of acute rejection in the infant heart transplant recipient.

Acute Disease↗
PubMedDate not supplied

Triple-drug immunosuppression for heart transplantation in infants and children.

Triple-drug immunosuppression with OKT3 induction is effective rejection prophylaxis in pediatric cardiac allograft recipients. The concerns regarding prevalent lymphoproliferative disease, growth retardation, cytomegalovirus, and other opportunistic infections have not been realized. Since June 1986, 34 pediatric patients, 23 males and 11 females, (age 4 days to 15 years) have undergone orthotopic heart transplantation at our institution. Fifteen patients were less than 6 months old and 13 had type I or II hypoplastic left heart syndrome. There have been four (12%) operative and four (12%) late deaths and a survival rate of 76% after a mean follow-up of 33 months (range, 1 to 82 months). The only deaths attributed to allograft rejection occurred in two newborn recipients (2 and 10 months after surgery) who neither received maintenance steroids nor underwent routine biopsy. The only death from infection (pneumococcus) occurred 6 months after surgery in a 4-year-old patient who was not known to be asplenic. Of the 27 long-term (> 1 year) survivors, 17 (68%) had an average of two rejection episodes during the follow-up period, 10 patients (32%) have been free of graft rejection, and 26 patients (96%) have not experienced a cytomegalovirus infection despite OKT3 induction therapy. Two patients developed lymphoproliferative disease, one of whom was successfully treated by transient reduction of immunosuppression. The other patient died 13 months after transplantation of a lymphoma of the central nervous system. All survivors have demonstrated satisfactory increases in mean height and weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Cost-benefit analysis of an automated medication system.

Automated medication distribution systems have helped solve issues of efficiency and effectiveness. Cost-benefit analysis conducted by nursing and pharmacy departments can help to objectify the decision to adopt this technology.

Capital Expenditures↗