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Biomedical subjects

C R Smith

Publications and source records attributed to C R Smith.

At least 217 records · Page 12Linked to original sources
PubMed1988

Effect of low-dose alcohol use versus abstention on apolipoproteins A-I and B.

An inverse association between low to moderate alcohol consumption and coronary heart disease has been demonstrated in epidemiologic studies of diverse design. An attempt was made to determine if this association might be due to an effect of alcohol on apolipoproteins A-I and B and to determine if low-dose alcohol intake might have a potentially protective effect by this mechanism in persons at increased risk for coronary heart disease. To address this, an eight-week prospective randomized clinical trial of abstention versus low-dose alcohol consumption, defined as one beverage per day, was conducted in white men, aged 21 to 60 years, most of whom were patients of a preventive cardiology program. Apolipoprotein A-I levels had a mean increase of 9 mg/dl in the 28 participants who drank alcohol compared with a mean decline of 5 mg/dl in the 28 participants who abstained (p less than 0.005). This association was independent of other cardiovascular risk factors. Low-density lipoprotein (LDL)-B levels had a mean increase of 7 mg/dl in both arms of the trial (NS). However, the ratio of apolipoprotein A-I to LDL-B increased by 4 percent in the drinkers and decreased 10 percent in the abstainers (p less than 0.03). No significant changes in mean levels of total high-density lipoprotein (HDL)-, HDL2-, or HDL3-cholesterol were observed with this low dose of alcohol. This effect on apolipoprotein A-I suggests a possible mechanism by which low-dose alcohol may lower the risk of coronary heart disease.

Adult↗
PubMed1988

Congenital tracheal stenosis: a review of 22 patients from 1965 to 1987.

Twenty-two infants with congenital tracheal stenosis (CTS) were treated in our hospital between 1965 and 1987. Diagnosis was confirmed by endoscopic and radiographic methods. Patients had a spectrum of tracheobronchial lesions from localized stenosis to more complex deformities involving the carina and bronchi. Other anomalies were found in all patients with the occurrence of vascular slings or rings in 11 patients (50%). Six infants treated nonoperatively died from severe CTS and other lethal anomalies. Five of 16 patients (31%) treated surgically survived. Localized CTS in four cases was treated by dilatation, tracheostomy, or tracheal resection with primary anastomosis (two survivors, 2 non-survivors). Funnel-shaped deformities and extensive tracheobroncial stenosis were treated by tracheal reconstruction using a variety of autogenous tissue and prosthetic grafts (three survivors, nine non-survivors). The overall mortality was 77%. A new intratracheal stent was used in two patients. The stent was a flexible steel spring covered with a silicone rubber sheath. In one patient, it was placed within the trachea at the time of repair and removed later with the bronchoscope. A stent was used in a second patient with intermittent airway obstruction following an esophageal tracheoplasty. In this case, the device failed to alleviate the obstruction, and the infant expired from progressive respiratory failure. Issues of importance in the management of infants with CTS are: (1) adequate evaluation of the tracheobronchial tree, (2) awareness that tracheobronchography may precipitate further respiratory decompensation, (3) assessment of vascular and other anomalies requiring surgical correction, and (4) selection of an appropriate therapeutic approach.

Female↗
PubMed1988

The histopathology of the hemolytic uremic syndrome associated with verocytotoxin-producing Escherichia coli infections.

Verocytotoxin-producing Escherichia coli (VTEC) infection was present in three cases of hemolytic uremic syndrome (HUS), two fatal and one non-fatal, in which detailed histopathologic investigations were conducted. Two patients had a prodrome of bloody diarrhea, one of whom required a hemicolectomy for severe bleeding. The renal histopathology was characterized primarily by glomerular thrombotic microangiopathy (TMA) with greater than 95% of glomeruli showing changes of capillary wall thickening, endothelial cell swelling, and narrowing or thrombosis of the capillary lumen. Preglomerular arterioles were frequently thrombosed, and abnormalities of the medium-sized vessels, including endothelial cell damage and thrombosis, were also commonly observed. Gastrointestinal involvement was prominent in all three cases. The colon was most severely involved, with marked mucosal and submucosal edema and hemorrhage, in the absence of significant inflammation or widespread ulceration. Microvascular angiopathy was present in all cases, with changes ranging from endothelial cell damage to overt thrombosis. Similar pathology was seen throughout the small bowel, including the presence of TMA. In one patient, typical morphologic changes of pseudomembranous enterocolitis were found in the absence of infection with Clostridium difficile. The nature of vascular involvement in the kidneys and intestinal tract supports the hypothesis that HUS is mediated by systemic toxemia, and that endothelial cells are the primary target cells for the action of verocytotoxin.

Bacterial Toxins↗
PubMed1988

Effects of prednisone, aspirin, and acetaminophen on an in vivo biologic response to interferon in humans.

In healthy volunteers receiving a single intramuscular dose of 18 X 10(6) U interferon alone or after 24 hours of an 8-day course of prednisone (40 mg/day), aspirin (650 mg every 4 hours), or acetaminophen (650 mg every 4 hours), the magnitude of the biologic response to interferon was quantified by measuring the time course of the induction of 2'-5'-oligoadenylate synthetase and resistance to vesicular stomatitis virus infection in human peripheral blood mononuclear cells. Prednisone decreased the AUC of 2'-5'-oligoadenylate synthetase activity (p less than 0.05), whereas administration of aspirin or acetaminophen did not affect this biologic response. No measurable effect was seen during administration of prednisone, aspirin, or acetaminophen on the duration or intensity of vesicular stomatitis virus yield reduction. The side effects seen with interferon administration at the dose tested were not altered in a clinically meaningful manner by prednisone, aspirin, or acetaminophen.

2',5'-Oligoadenylate Synthetase↗
PubMed1988

The spiramycin paradox.

Spiramycin has been found to be effective in a variety of clinical and experimental infections despite modest in-vitro activity. In animal models of infection, spiramycin has been found to be as effective as or more effective than erythromycin despite inferior in-vitro activity. These paradoxical results are explained in part by spiramycin's ability to achieve intra-cellular and tissue concentrations that exceed serum concentrations by a factor of ten or more. Furthermore, spiramycin clearance from these sites is much lower resulting in sustained tissue and intracellular concentrations. Finally, spiramycin appears to produce a substantial post-antibiotic effect and, possibly, subinhibitory effects that may further enhance its in-vivo activity.

Animals↗
PubMed1988

Relapsing polychondritis and Weber-Christian disease.

A patient with classical relapsing polychondritis in whom abdominal pain was a prominent symptom is described. Histological examination of skin and mesenteric biopsies confirmed the diagnosis of Weber-Christian disease (systemic panniculitis) suggested by clinical features. The prognostic and therapeutic implications of this unusual disease association are discussed.

Adult↗
PubMed1988

Respiratory complications of cardiac transplantation.

The authors evaluated all respiratory complications of cardiac transplantation in a 10-year study of 94 consecutive recipients. Mean follow-up time was 20 +/- 17 months. The initial 20 patients were treated with azathioprine and prednisone, while the subsequent 74 patients received cyclosporine and prednisone. In the azathioprine group, respiratory infections accounted for 24 of 60 (40%) infections. Two-thirds of the respiratory infections occurred in the first 3 postoperative months and were generally localized processes (focal pneumonitis, nodule(s), abscess, or empyema). Gram-positive and gram-negative bacteria (8/30) and aspergillus (8/30) were the predominant pathogens. Respiratory failure occurred in 29% of infectious episodes. In the cyclosporine group, there were significantly fewer respiratory infections. There was also a reduction in the number of nonrespiratory infections; hence, the percentage of total infections due to respiratory causes, 26 of 50 (52%), was not significantly different. In contrast, however, nearly two-thirds of the respiratory infections in cyclosporine-treated patients occurred after the first 3 postoperative months, and were usually diffuse processes. Despite diffuse disease, respiratory failure was observed with similar frequency (19%). Pneumocystis carinii (9/31) and cytomegalovirus (CMV) (7/31) were the predominant pathogens. CMV pneumonitis tended to occur earlier than that due to P. carinii (2.9 +/- 1.9 mo vs. 9.8 +/- 11.2 mo, respectively), but there was considerable overlap. In comparison with infectious processes, there were 50% fewer noninfectious respiratory complications in both groups. These were primarily pleural (46%) or thromboembolic (18%) disorders. Four of five pulmonary emboli occurred in patients with intercurrent cardiorespiratory illness, and were detected only at autopsy. The authors conclude that respiratory infections account for one-half of all infections observed in cardiac transplant recipients, despite the reduced infection rate associated with the use of cyclosporine. Furthermore, respiratory infections in cyclosporine-treated patients exhibit different clinical and etiologic features than those seen in azathioprine-treated patients. Finally, occult thromboemboli may be difficult to recognize in cardiac transplant recipients because of the high incidence of coexisting cardiorespiratory disease.

Adult↗
PubMed1988

Contrast medium-induced adverse reactions: economic outcome.

Because the cost of managing an expected greater number of adverse reactions when high-osmolality contrast media (HOM) are used could offset the higher material cost of low-osmolality contrast media (LOM), a prospective study was done of 795 inpatients undergoing any of four procedures involving intravascular injection of HOM: cardiac catheterization, peripheral angiography, head computed tomography (CT), or body CT. The resources used in managing HOM-induced adverse reactions were measured, and the costs of these resources were estimated. Four hundred five patients (51%) had adverse reactions. Reactions were grouped into three classes according to their severity. Class 1 (mild) reactions occurred in 358 patients (45%), class 2 (moderate) reactions occurred in 44 patients (6%), and class 3 (severe) reactions occurred in three patients (0.4%). Ninety-nine patients (12%) consumed resources as a result of an adverse reaction. The average cost of these resources per patient undergoing examination was $1.07 to the radiology department, $5.83 to the hospital, and $12.93 to a charge-paying insurer. Mean (+/- standard deviation) cost to the hospital for managing class 1, class 2, and class 3 reactions were $2.52 +/- $5.33, $24 +/- $54, and $910 +/- $749, respectively. By comparison, the difference in material cost of HOM versus LOM ranged from $93 for body CT to $179 for cardiac catheterization. Even if LOM were to induce no adverse reactions, the increased material cost associated with universal substitution of LOM for HOM would be greater than the expected cost of managing adverse reactions when HOM are used.

Adult↗
PubMed1988

Biological activity of serum prolactin in patients with primary hypothyroidism.

Prolactin bioactivity was measured in sera from 22 patients with primary hypothyroidism and 13 euthyroid control subjects and compared with estimates of immunoactivity given by radioimmunoassay. The Nb2 rat lymphoma cell assay was modified to improve specificity for prolactin and used to measure bioactivity. Results of serum prolactin levels obtained using the bioassay were closely correlated with radioimmunoassay results in both hypothyroid patients and control subjects. Mean bioactivity/immunoactivity ratios in patients were not significantly different from those in control subjects. Mean prolactin concentration measured by both assays was significantly higher in patients than control subjects. Serum prolactin in patients with primary hypothyroidism appears to have essentially normal bioactivity as measured in the Nb2 assay, in contrast with a report of major differences between activity in radioreceptor assay and RIA in hypothyroid patients.

Animals↗
PubMed1988

Utility of airway endoscopy in the diagnosis of respiratory complications of cardiac transplantation.

We evaluated 39 episodes (in 32 patients) of pulmonary parenchymal infiltrates following cardiac transplantation with fiberoptic bronchoscopy (FOB) in a prospective study of 94 consecutive recipients. Initial FOB established the diagnosis in 24/39 (62 percent) instances. Subsequent examinations included repeat FOB (five), open lung biopsy (five), needle aspiration (two), and autopsy (nine), establishing 49 diagnoses. Specific pathogens were identified in 45 instances, neoplasm in two, and idiopathic interstitial pneumonitis in two. Bronchoalveolar lavage alone yielded diagnoses in 63 percent and transbronchial biopsy and bronchial washings/brushings in 46 and 43 percent, respectively. Transbronchial biopsy suggested idiopathic interstitial pneumonitis in 17 instances, but four had spontaneous clearing, and open lung biopsy or autopsy showed alternative diagnoses (particularly CMV and Aspergillus) in 11. The main complication of FOB was moderate (25 to 100 ml) hemorrhage after transbronchial biopsy (10 percent); no severe episodes occurred despite elevated pulmonary vascular pressures. In this population of immunocompromised hosts: (1) bronchoalveolar lavage is the most sensitive bronchoscopic technique for detecting infection; (2) transbronchial biopsy is not useful in detecting CMV or Aspergillus infection; (3) pulmonary hypertension is associated with some risk of moderate but not severe hemorrhage after transbronchial biopsy.

Adult↗
PubMed1988

Physician knowledge, attitudes, and behavior related to reporting adverse drug events.

Voluntary physician reporting of adverse drug events (ADEs) in their patients remains the single most important source of information on serious and rare ADEs. Yet, substantial underreporting exists and the factors producing it are unclear. We surveyed 3000 randomly chosen physicians by mailed questionnaire to determine their knowledge about the reporting system, attitudes toward reporting, and their past behavior in reporting the ADEs they had detected. Responses numbered 1121. Only 57% were aware of the Food and Drug Administration's reporting system. While 418 physicians had detected an ADE in their practices during the previous year, only 21 physicians reported these events directly to the Food and Drug Administration. The physicians appear to appreciate the safety issues involved in prescription drug use and view reporting as a professional obligation; however, the current reporting system is considered inconvenient.

Attitude↗
PubMed1987

Trimodal evoked potentials compared with magnetic resonance imaging in the diagnosis of multiple sclerosis.

Twenty-three patients with the clinical diagnosis of possible multiple sclerosis (MS) were tested with magnetic resonance imaging (MRI) and trimodal evoked potentials. Fourteen patients showed abnormalities on both MRI scans and at least one evoked potential modality (65%). Four patients had normal MRI scans but at least one abnormality on evoked potential testing (17%). One patient had normal triple evoked potentials with an abnormal MRI result. Four patients had normal results on both MRI and triple evoked potential testing; two of these patients were later found to have immunologic abnormalities in the cerebrospinal fluid consistent with the diagnosis of MS. Combined evoked potential testing was found to have a higher sensitivity than MRI in confirming a diagnosis of MS. Three patients with the clinical diagnosis of definite MS were also tested. All these patients showed abnormalities on evoked potential testing, although one patient had a normal MRI result. Of all 26 patients who were studied, 17 showed abnormal MRI results and 21 showed at least one abnormality on evoked potential testing.

Adult↗
PubMed1987

Clinical response to aminoglycoside therapy: importance of the ratio of peak concentration to minimal inhibitory concentration.

In an examination of the relationships among plasma aminoglycoside concentrations, the minimal inhibitory concentration (MIC) for the infecting organism, and therapeutic outcome, data were analyzed from 236 patients with gram-negative bacterial infections who were participants in four clinical trials of gentamicin, tobramycin, and amikacin. Clinical response to therapy occurred in 188 (80%) patients. Elevated maximal and mean peak aminoglycoside concentration/MIC ratios were strongly associated with clinical response (P less than .00001 and P less than .0001, respectively). A graded dose-response effect was found between an increasing maximal peak concentration/MIC ratio and clinical response. By logistic regression the peak concentration/MIC ratios were associated significantly with clinical response after adjustment for underlying severity of illness and other factors correlated with response. These results demonstrate that a high peak concentration relative to the MIC for the infecting organism is a major determinant of the clinical response to aminoglycoside therapy.

Adult↗