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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 361 records · Page 20Linked to original sources
PubMed1990

Effects of exercise, dietary cholesterol, and dietary fat on blood lipids.

Exercise, a low fat diet, or a diet low in saturated fat content can each lower plasma total cholesterol and low-density lipoprotein (LDL) cholesterol. We investigated whether these factors together could prevent the lipid-raising effects of dietary cholesterol. Ten healthy, athletic, normolipidemic male volunteers were studied. Two diets of 4 weeks duration each were compared in a randomized, blind crossover design. Diets were identical except for cholesterol content: one contained 600 mg/d; the other 200 mg/d. Both diets contained 15% of calories as protein, 55% as carbohydrate, 30% as fat, and the polyunsaturated fat to saturated fat ratio was 1.5. Exercise level and body weight were kept constant in each subject. As compared with plasma values obtained following the 200-mg/d cholesterol diet, mean values following the 600-mg/d cholesterol diet significantly increased for LDL cholesterol and apolipoprotein B by 10% and 13%, respectively. Mean plasma triglycerides, high-density lipoprotein 2 and 3, and apolipoprotein A-1 levels did not change significantly. Individual responses, however, were highly variable. Three subjects increased LDL cholesterol by more than 25%; 2 subjects increased LDL cholesterol by 10% to 25%; and 5 subjects had 5% or less change in LDL cholesterol. A dietary cholesterol increase can significantly elevate plasma LDL cholesterol and apolipoprotein B in certain normolipidemic, healthy men even when they are exercising regularly and consuming a moderately fat restricted, low saturated fat diet. Dietary cholesterol restriction may therefore be justifiable even when other life-style and dietary measures to minimize blood cholesterol are undertaken.

Adult↗
PubMed1990

Management of preterm labor patients at home: does daily uterine activity monitoring and nursing support make a difference?

Daily home uterine activity monitoring and perinatal nursing support were compared with standard care in managing patients with recurrent preterm labor during the current pregnancy in an effort to reduce preterm birth. Sixty-seven successfully treated preterm labor patients were randomly assigned in this multicenter study to daily home uterine activity monitoring and perinatal nursing support or to a standard-care group. Recurrent preterm labor occurred in 15 (45%) of monitored patients and 19 (56%) of standard-care patients. The risk of preterm birth (before 37 weeks) for patients with recurrent preterm labor was significantly reduced (P = .025) in the monitored group (seven, or 47%) compared with the standard-care group (16, or 84%). The relative risk of delivering because of failed tocolysis was 2.8 for the standard-care group versus the monitored group. There were no patients in the monitored group who delivered at the first recurrence of preterm labor for failed tocolysis. The data suggest that home uterine activity monitoring and perinatal nursing support are helpful in achieving term birth through earlier detection and treatment of recurrent preterm labor.

Adult↗
PubMed1990

Characteristics of uterine activity in gestations less than 20 weeks.

Ambulatory tocodynamometry has been used for some time to record uterine activity during pregnancy. Most studies, however, have been performed in the third trimester (more than 24 weeks). The current study was initiated to assess uterine activity at earlier gestational ages. One hundred thirty-seven patients were studied between 14-19 weeks' gestation (inclusive). Seven patients who were being monitored were noted to have preterm labor, and six of these seven were found to have increased uterine activity before the diagnosis of preterm labor. There was no difficulty encountered in the vast majority of cases in recording objective, accurate uterine activity information even at these early gestational ages. There was an increase in the uterine activity (during the 18th and 19th weeks) in patients destined to develop preterm labor later in gestation as compared with the contraction pattern of those who labored at term. This study demonstrates that accurate uterine activity information can be gained at these early gestational ages and that when increased contraction frequency is present, it is related to preterm labor.

Adult↗
PubMed1989

Purification and characterization of an erythrocyte membrane protein complex carrying Duffy blood group antigenicity. Possible receptor for Plasmodium vivax and Plasmodium knowlesi malaria parasite.

A murine monoclonal antibody, named anti-Fy6, which agglutinates all human red cells except those of Fy(a-b) phenotype was used for purification and characterization of Duffy antigens. Duffy antigens are multimeric red cell membrane proteins composed of different subunits of which only one, designated pD protein, reacts in immunoblots with the murine monoclonal antibody anti-Fy6. Affinity-purified detergent-soluble antigen-antibody complex obtained from red cells, surface-labeled with 125I yielded a complex pattern of bands when separated by polyacrylamide gel electrophoresis. Proteins that react with anti-Fy6 in immunoblots are: pA and pB (greater than 100 kDa) and pD (36-46 kDa). Electroeluted pD protein aggregates and generates bands of similar molecular mass to pA and pB proteins. Electroeluted pA and pB proteins disaggregate yielding pD protein. Oligomers and monomers of pD protein are present in red cells carrying Duffy antigens and absent in Fy(a-b-) cells. Six other proteins of molecular weight ranging from 68 to 21 kDa either associate or co-purify with pD protein. These proteins are only present in Duffy antigen positive cells. The pD protein is different in Fy(a+b-) and Fy(a-b+) cells by fingerprint analysis. Human antisera identify the same proteins in red cell carrying Duffy antigens as the murine monoclonal antibody anti-Fy6.

Animals↗
PubMed1989

Structural adaptations of the femur and humerus to arboreal and terrestrial environments in three species of macaque.

One reason to measure cross-sectional structural properties of primate long bones is to define mechanically relevant complexes of traits that describe the adaptation of bone to different biomechanical environments. This can be effectively accomplished when congeneric species having different postural and locomotor behaviors are compared. This paper compares the cross-sectional geometry of the femur and humerus in three behaviorally different macaque species as a basis for defining such patterns. Cross-sectional moments of inertia in the standard anatomical planes were calculated at five locations along the diaphyses of the femur and humerus in Macaca fascicularis, M. nemestrina, and M. mulatta. The data suggest that the "barrel-shaped" femur is associated with behaviors for which long limbs and small body size are an asset. This may be associated with, but is not restricted to, leaping behaviors. The data also suggest that structural rigidity of the femur and humerus is greater per unit body weight in primates that spend significant amounts of time in terrestrial environments than in those that are more restricted to climbing in arboreal environments.

Analysis of Variance↗
PubMed1989

Effects of beta-carboline-ethyl ester on plasma corticosterone--a parallel with antagonist-precipitated diazepam withdrawal.

Diazepam has been shown to produce physical dependence based on observations of behavioral stimulation or, in our laboratory, by increases in plasma corticosterone (CS) during antagonist-precipitated withdrawal. The behavioral excitation appears similar to that observed following the administration of beta-carboline esters--agents reported to interact with benzodiazepine receptors and termed "inverse agonists." The focus of the present study is to correlate the occurrence of changes in CS with behavioral excitation previously observed by others. Further, these studies are designed to show a parallel between the manifestations of benzodiazepine withdrawal and the pharmacologic effects of beta-carboline ethyl ester. Experiments were done in conscious unrestrained male Sprague-Dawley rats, with chronic i.v. catheters, using sound-attenuated one-way vision boxes. These studies compared the hormonal and behavioral changes induced by beta-carboline ethyl ester (beta CCE) with CGS-8216-precipitated withdrawal in rats treated with diazepam for 8 days. Rats treated chronically with diazepam (5 mg/kg/day), showed a significant increase in plasma (CS) following CGS-8216. Behavioral abstinence scores were also significantly elevated. beta CCE (0.5-5.0 mg/kg) showed a significant dose-related increase in plasma CS. Behavioral scores were also increased at doses of 0.5 and 2.0 mg/kg. beta CCE-induced plasma CS increases were antagonized by CGS-8216 at doses of 1.0 and 2.0 mg/kg but not by 0.5 mg/kg. In animals chronically treated with diazepam, beta CCE evoked a more prolonged plasma CS elevation than in vehicle-treated animals suggesting a dual agonist/antagonist effect. These data suggest a parallel between CS elevations and behavioral effects during withdrawal as well as similarities between the action of beta CCE and the manifestations of this withdrawal.

Animals↗
PubMed1989

Onset of action between bupivacaine 0.5% and bupivacaine 0.5% plus fentanyl 75 mcg.

This study tested the hypothesis that the addition of fentanyl 75 mcg to bupivacaine 0.5% at the onset of epidural anesthesia for cesarean section reduces the onset time for T4 sensory blockade. The study was conducted in a randomized, double-blind fashion. The same observer performed sensory testing using pain to pinprick. Fourteen ASA I patients scheduled for elective cesarean section had epidural catheters placed. Group 1 (n = 7) received bupivacaine 0.5%, and group 2 (n = 7) received bupivacaine 0.5% plus fentanyl 75 mcg. Patients 5'0'' to 5'4'' in height received 15 ml, and patients 5'5'' to 5'9'' received 20 ml of bupivacaine. There were no adverse effects on the neonate or clinically important changes in maternal hemodynamics. The maternal age, height, weight, and bupivacaine dose did not differ between groups (p greater than 0.05). For group 1, the mean times for sensory loss at T7, T6, T5, and T4 were 13.1 +/- 3.8 minutes, 15.0 +/- 4.0 minutes, 16.9 +/- 4.3 minutes, and 19.3 +/- 4.9 minutes, respectively; for group 2, the mean times were 8.1 +/- 0.9 minutes, 9.9 +/- 1.1 minutes, 11.3 +/- 1.5 minutes, and 12.7 +/- 2.0 minutes, respectively. Two-factor analysis of variance between groups 1 and 2 showed a significant difference (p less than 0.0001), representing a 35% reduction of mean onset time. The coefficient of variation of the mean onset times for group 1 subjects was 26.6% +/- 1.7% and for group 2 subjects 12.7% +/- 2.2% (p less than 0.001), representing a 50% reduction in between-subject variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Clinical competence in the performance of fiberoptic laryngoscopy and endotracheal intubation: a study of resident instruction.

Anesthesiologists must be competent in the technique of fiberoptic laryngoscopy and intubation in airway management. The goal of this study was to test the hypothesis that an acceptable level of technical expertise in fiberoptic laryngoscopy and intubation may be acquired within 10 intubations while maintaining patient safety. The learning objectives were an intubation time of 2 minutes or less and greater than 90% success on the first intubation attempt. Ninety-one ASA physical status I-II patients with normal laryngeal anatomy had general anesthesia and were intubated orally with an Olympus LF-1 fiberoptic scope; the mean (+/- SD) time for intubation was 1.92 +/- 1.45 minutes. Four residents with no prior experience with fiberoptic laryngoscopy intubated at least 15 patients each. A learning curve was generated using logarithmic analysis of the mean (+/- SD) time for intubation of patients 1 to 15 for all residents combined. The curve showed that the mean (+/- SD) intubation time decreased from 4.00 +/- 2.91 to 1.53 +/- 0.76 minutes within the first 10 intubations. After the tenth intubation, the mean time was 1.53 minutes and the percent success on the first attempt at intubation was greater than 95%. There were no clinically important changes in O2 saturation, mean arterial pressure (MAP), or heart rate (HR) as a consequence of fiberoptic intubation. The results suggest that an acceptable level of technical expertise in fiberoptic intubation can be obtained (as defined by the learning objectives) by the tenth intubation, and patient safety is maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

High density lipoprotein cholesterol levels among US adults by selected demographic and socioeconomic variables. The Second National Health and Nutrition Examination Survey 1976-1980.

The distribution of serum high density lipoprotein cholesterol (HDL cholesterol) levels was determined on a nationally representative sample of 9,625 adults aged 20-74 years, as part of the Second National Health and Nutrition Examination Survey, 1976-1980 (NHANES II). Mean HDL cholesterol levels were higher in women compared with men (an age-adjusted difference of 8.9 mg/dl for whites and 4.4 mg/dl for blacks). HDL cholesterol levels were higher in blacks compared with whites (an age-adjusted difference of 7.4 mg/dl for men and 2.8 mg/dl for women). All differences were statistically significant (p less than 0.01). These relations remained after stratification by age, income, poverty index, education, body mass index, alcohol consumption, cigarette smoking, and physical activity. For whites, HDL cholesterol levels were highest in the highest category of earnings, whereas blacks generally had lower levels of HDL cholesterol with increased earnings. In a multivariate model, important predictors of higher HDL cholesterol levels were being female, being black, and reporting a higher frequency of alcohol consumption. Less strongly related were age, years of education, and reported high physical activity. Smoking and body mass index were strongly negatively related to HDL cholesterol levels. The findings in this national study support previous findings in selected populations in the United States.

Adult↗
PubMed1989

Production and release of C3 by cultured monocytes/macrophages isolated from burned, trauma, and septic patients.

The release of C3 under various conditions by cultured monocytes/macrophages isolated from burned, trauma, and septic trauma patients was determined. When monocytes were cultured for up to 14 days there was no difference in production and release of C3 by normals and patients; C3 production rose slowly at first then rose rapidly from 8-14 days of culture. C3 production continued for up to 28 days of culture. When lymphocytes were present with the monocytes for the first 24 hr of culture there were differences in C3 production by normal and patient cells at various times of culture. There were differences in C3 release by patients' 24 hour-cultured cells at certain postburn and injury days. Macrophages from burned patients released less C3 than normal cells and macrophages from septic trauma patients released more C3 than normal cells.

Burns↗
PubMed1989

Ofloxacin versus trimethoprim-sulfamethoxazole for treatment of acute cystitis.

We compared the safety and efficacies of ofloxacin and trimethoprim-sulfamethoxazole for the treatment of acute uncomplicated cystitis in women enrolled in a multicenter study. Data from three centers were combined for this report because the study design and study populations were identical, and patients were enrolled within an 18-month period. Cure rates for evaluable patients 4 weeks after treatment were high for all regimens: ofloxacin (200 mg) twice daily for 3 days, 22 of 25 (88%) cured; ofloxacin (200 mg) twice daily for 7 days, 42 of 49 (86%) cured; ofloxacin (300 mg) twice daily for 7 days, 25 of 25 (100%) cured; and trimethoprim-sulfamethoxazole (160/800 mg) twice daily for 7 days, 46 of 52 (88%) cured. Ofloxacin was more effective than trimethoprim-sulfamethoxazole in eradicating Escherichia coli from rectal cultures during and 1 week after treatment. Both ofloxacin and trimethoprim-sulfamethoxazole markedly reduced vaginal colonization with E. coli during and 4 weeks after therapy. Emergence of resistant coliforms in rectal flora was found in 5 (19%) of 27 patients treated with trimethoprim-sulfamethoxazole but none of 50 ofloxacin-treated patients who were studied (P = 0.004). Adverse effects were equally common among the four treatment groups. We conclude that 3 to 7 days of ofloxacin is as safe and effective as trimethoprim-sulfamethoxazole for treatment of uncomplicated cystitis in women and that ofloxacin effectively reduces the fecal and vaginal reservoirs of coliforms in such patients.

Acute Disease↗
PubMed1989

Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro.

Previous studies have demonstrated that the Escherichia coli dnaK and grpE genes code for heat shock proteins. Both the Dnak and GrpE proteins are necessary for bacteriophage lambda DNA replication and for E. coli growth at all temperatures. Through a series of genetic and biochemical experiments, we have shown that these heat shock proteins functionally interact both in vivo and in vitro. The genetic evidence is based on the isolation of mutations in the dnaK gene, such as dnaK9 and dnaK90, which suppress the Tr- phenotype of bacteria carrying the grpE280 mutation. Coimmunoprecipitation of DnaK+ and GrpE+ proteins from cell lysates with anti-DnaK antibodies demonstrated their interaction in vitro. In addition, the DnaK756 and GrpE280 mutant proteins did not coimmunoprecipitate efficiently with the GrpE+ and DnaK+ proteins, respectively, suggesting that interaction between the DnaK and GrpE proteins is necessary for E. coli growth, at least at temperatures above 43 degrees C. Using this assay, we found that one of the dnaK suppressor mutations, dnaK9, reinstated a protein-protein interaction between the suppressor DnaK9 and GrpE280 proteins.

Bacteriophage lambda↗
PubMed1989

Pathogenesis and epidemiology of chronic pancreatitis.

Acute pancreatitis is not the cause but may be a complication of chronic pancreatitis. Different forms of chronic pancreatitis are described. The most frequent type in all climates, chronic calcifying pancreatitis, has different causes but similar pathological changes. It is a lithiasis in which a new family of molecules. PSP, a calcium stabilizer, plays a dominant role. Studies of chronic pancreatitis have now reached the stage of molecular biochemistry.

Alcoholism↗
PubMed1989

Renal subcapsular islet cell transplantation in the dog. A preliminary report.

During the last two decades, islet cell transplantation has been pursed both experimentally and clinically in an effort to ameliorate diabetes mellitus. At present, however, islet cell transplantation still remains at the experimental stages as far as the treatment of diabetes is concerned. Also, culture of islet cells has proved to be rather frustrating and difficult. No consistent techniques have been developed, and simplified methods for islet cell preparation and adequate sites for islet cell placement would allow for further progress in this area. Ultimately, rejection remains the greatest obstacle to success. We report a simplified technique for enriching dog pancreatic islet cells. This preparation was injected into the renal subcapsular space in both homograft (3 experiments) and heterograft (3 experiments) situations. After six weeks, nephrectomy was performed, and histochemical techniques demonstrated many groups of live islets in between the tubules in the renal cortex. No acinar cells were observed. Blood samples from the renal artery and renal vein at the time of nephrectomy revealed an average 36.9% increase in insulin concentration in the renal veins, supporting an active secretory role of these transplanted islet cells. This technique points to (i) the possible role of "renal factor" in promoting growth of islet cells and (ii) the feasibility of successful transplantation of enriched islet cells as a potential approach to the curative treatment of diabetes mellitus.

Animals↗