Biomedical subjects

G W Reed

Publications and source records attributed to G W Reed.

At least 37 records · Page 2Linked to original sources

PubMed1996

Base deficit and oxygen transport in severe preeclampsia.

OBJECTIVE: To evaluate the relationship of anaerobic metabolism, as reflected by the calculated base deficit, with oxygen transport and left ventricular function in women with severe preeclampsia. METHODS: Forty women with singleton pregnancies and severe preeclampsia who met prescribed criteria for invasive hemodynamic monitoring had arterial blood gas and hemodynamic values obtained immediately after placement of a pulmonary artery catheter. Oxygen transport indices were stratified according to the admission base deficit. RESULTS: Linear regression analysis demonstrated a strong negative correlation between the calculated base deficit and the oxygen delivery index (r = -0.64), cardiac index (r = -0.62), and left ventricular stroke work index (r = -0.58). A baseline maternal base deficit exceeding -8.0 mEq/L consistently predicted fetal acidosis, fetal death, and maternal end-organ ischemic injury. CONCLUSION: The calculated base deficit reliably reflects maternal oxygen transport dynamics and identifies patients at risk for end-organ injury. Ventricular contractility and oxygen delivery decline with mounting oxygen debt.

Adolescent↗

PubMed1996

Measuring the thermic effect of food.

The thermic effect of food (TEF), defined as the increase in metabolic rate after ingestion of a meal, has been studied extensively, but its role in body weight regulation is controversial. We analyzed 131 TEF tests from a wide range of subjects ingesting meals of varying sizes and compositions. Each test lasted 6 h. Of the total 6-h TEF, 60% of the total had been measured after 3 h. 78% after 4 h, and 91% after 5 h. We developed a three-parameter curve to fit the data, which reduced noise and gave additional information about the TEF. The area under this parametric curve was positively correlated with fat-free mass (FFM) and meal size (MS) and negatively correlated with meal size squared (MS2) with an R2 of 0.35. The usual area under a curve created by connecting the data points of a line was correlated with the same factors but with an R2 of 0.28. The peak of the parametric curve was positively correlated with FFM and MS and negatively correlated with MS2, percent body fat, and meal composition. The time at which the peak occurred correlated positively with MS and percent fat in the meal. Our analysis suggests that an inadequate measurement duration of the TEF could lead to errors. In general, we recommend that the TEF be measured for > or = 5 h.

Adolescent↗

PubMed1996

The seroepidemiology of Bordetella pertussis infections: a study of persons ages 1-65 years.

Although the incidence of Bordetella pertussis infections had decreased significantly since the introduction of widespread vaccination, an increase in the number of cases has occurred recently. In an attempt to define the seroepidemiology of pertussis in Nashville, antibody levels to pertussis toxin (PT) and filamentous hemagglutinin (FHA) were measured by ELISA in 585 serum samples from healthy 1- to 65-year-old subjects. Data were analyzed by smooth curve fitting and by comparison of trends in PT and FHA titers across age groups. The results demonstrated a peak in PT and FHA titers in the 4-6 year age group, concurrent with the administration of booster doses of diphtheria-tetanus toxoid-pertussis vaccine. A second larger peak was noted in the 13-17 year age group. These data suggest that pertussis infection is frequent during the adolescent years.

Adhesins, Bacterial↗

PubMed1996

Evaluation of live attenuated influenza vaccines in children 6-18 months of age: safety, immunogenicity, and efficacy. National Institute of Allergy and Infectious Diseases, Vaccine and Treatment Evaluation Program and the Wyeth-Ayerst ca Influenza Vaccine Investigators Group.

Live attenuated, cold-adapted (ca) monovalent and bivalent influenza A vaccines were evaluated in seronegative infants (ages 6-18 months) in a double-blind placebo-controlled trial to assess safety and immunogenicity. A total of 182 seronegative subjects received a single intranasal dose (10(6.2) TCID50) of ca A/Kawasaki/9/86 (H1N1) or ca A/Los Angeles/2/87 (H3N2), both as a bivalent vaccine, or placebo. Respiratory and systemic symptoms did not differ between groups after vaccination. Hemagglutination antibody seroconversions (> or = 1:8) to H3N2 exceeded 90%. In contrast, seroconversions to A/Kawasaki/9/86 (H1N1) were significantly less frequent in bivalent ca vaccine recipients (31%) than in monovalent ca H1N1 recipients (83%) (P < .002). During a subsequent H3N2 epidemic, nasal washes were cultured for viruses from any subject with respiratory illness. H3N2 infections documented by virus isolation were reduced by 65% in ca H3N2 recipients compared with placebo or ca HIM recipients (P = .01).

Adaptation, Physiological↗

PubMed1996

Prevention of preterm birth. Role of daily telephone contact.

OBJECTIVE: To compare the effectiveness of routine management of patients at high risk for preterm delivery to the effectiveness of routine management in combination with daily telephone nursing contact. STUDY DESIGN: The control group, 1 (n = 21), had education and frequent prenatal visits and cervical examinations. The study group, 2 (n = 21), had education, frequent prenatal visits and cervical examination, and daily telephone contact. Group 3 (n = 22) received education but refused to participate. RESULTS: There were no significant differences (SD) between groups in race, smoking, age, multiple gestation, visits, diagnosis of premature labor, mean days gained after diagnosis of premature labor, tocolytic use or bed rest. There was also no SD in preterm birth rate, mode of delivery, number of maternal or neonatal hospital days, mean neonatal weight or gestational age at delivery between groups. While not reducing the overall incidence of preterm birth, this management for all groups resulted in a more advanced gestational age at the time of delivery (mean change = 7.5 weeks, P < .0001) when compared to the patient's first preterm birth. CONCLUSION: This study indicated that daily contact, while providing reassurance and support, did not change the outcome when the study group was compared to women managed similarly but without daily contact.

Adolescent↗

PubMed1995

Immunization coverage among infants enrolled in the Tennessee Medicaid program.

OBJECTIVES: To determine immunization coverage of infants receiving Medicaid in Tennessee and to identify risk factors for failure to complete recommended vaccinations by 24 months of age. DESIGN: Retrospective cohort study. SUBJECTS: A total of 33,615 children born in one of three urban Tennessee counties from 1980 through 1989 who were enrolled in Medicaid throughout their first 24 months of life. MAIN OUTCOME MEASURES: Receipt of four diphtheria-tetanus-pertussis, three oral polio, and one measles-mumps-rubella vaccines by 24 months of age (up-to-date), as recorded in computerized county immunization records and Medicaid billing files. RESULTS: Overall, 45% of infants enrolled in Medicaid in the three urban counties completed the recommended vaccinations by 24 months. The proportion of infants up-to-date peaked at 50% for those born in 1982 and 1983, and decreased to 44% for those born in 1989. The only strong independent predictors of immunization completion were number of prior births for the mother, timing of the first immunization, and county of birth. The proportion up-to-date was 56% for first-born children compared with 27% for those whose mothers had at least three prior births; 55% for those whose first immunization was on time compared with 22% for those with a delay in the first immunization; and 63%, 52%, and 37% for infants born in the three respective counties. Maternal age, education, race, and marital status predicted immunization completeness only weakly or not at all. CONCLUSIONS: Of infants born in the three counties in the 1980s who were enrolled in the Tennessee Medicaid program, fewer than half completed their recommended childhood vaccinations by 24 months of age. The large differences in immunization levels between infants enrolled in the Medicaid program in the three counties, not accounted for by differences in demographics, suggest that factors related to the health care and vaccine delivery system have important effects on achieving adequate immunization of these infants.

Child, Preschool↗

PubMed1995

Streptococcus pneumoniae colonization in the young child: association with otitis media and resistance to penicillin.

OBJECTIVE: To determine the nasopharyngeal colonization rate of penicillin-susceptible and penicillin-resistant strains of Streptococcus pneumoniae in young children, and to assess its relationship with the incidence of otitis media. DESIGN: Observational study in 215 children younger than 6 years of age who received care in the Vanderbilt Vaccine Clinic from September 1, 1992, to August 31, 1993. RESULTS: Of 842 nasopharyngeal cultures obtained, results for 44% of the cultures were positive for S. pneumoniae; 73% of the isolates were serotypes 6, 14, 19, or 23. Younger children had significantly higher rates of pneumococcal colonization than older children, with a peak at 1 year of age. By microdilution susceptibility testing, 37% of the cultures with positive results were intermediately or highly resistant to penicillin. Significantly more serotype 19 and 23 isolates were penicillin resistant than organisms of other serotypes. Children younger than 2 years of age had a twofold higher percentage of resistant isolates than those older than 2 years of age. A significant association was noted between nasopharyngeal carriage of S. pneumoniae and acute otitis media (p = 0.0002); however, the incidence of acute otitis media did not differ significantly between children colonized with penicillin-susceptible or penicillin-resistant strains. Unresolved otitis media was diagnosed more often in children who were colonized with resistant organisms than in children colonized with susceptible strains (p = 0.04). CONCLUSIONS: There was a high rate of nasopharyngeal carriage of penicillin-resistant S. pneumoniae in this population of young children. Nasopharyngeal colonization was associated with an increased incidence of acute otitis media, and penicillin resistance was associated with an increased incidence of unresolved otitis media.

Acute Disease↗

PubMed1995

Fat and carbohydrate overfeeding in humans: different effects on energy storage.

Both the amount and composition of food eaten influence body-weight regulation. The purpose of this study was to determine whether and by what mechanism excess dietary fat leads to greater fat accumulation than does excess dietary carbohydrate. We overfed isoenergetic amounts (50% above energy requirements) of fat and carbohydrate (for 14 d each) to nine lean and seven obese men. A whole-room calorimeter was used to measure energy expenditure and nutrient oxidation on days 0, 1, 7, and 14 of each overfeeding period. From energy and nutrient balances (intake-expenditure) we estimated the amount and composition of energy stored. Carbohydrate overfeeding produced progressive increases in carbohydrate oxidation and total energy expenditure resulting in 75-85% of excess energy being stored. Alternatively, fat overfeeding had minimal effects on fat oxidation and total energy expenditure, leading to storage of 90-95% of excess energy. Excess dietary fat leads to greater fat accumulation than does excess dietary carbohydrate, and the difference was greatest early in the overfeeding period.

Adolescent↗

PubMed1995

Seroresponse to trivalent oral poliovirus vaccine as a function of dosage interval.

Seroresponses to trivalent oral poliovirus vaccine are not uniform throughout the world. Definition of the variables that determine successful immunization is vital to ensure global polio eradication. One such variable may be dosage interval. To investigate this effect 108 infants were enrolled in a clinical trial and randomly assigned to receive three doses of trivalent oral poliovirus vaccine (standard United States formulation) at 2, 3 and 4 or 2, 4 and 6 months of age. After three doses of vaccine given before 6 months of age, immunity was virtually complete for each of the three poliovirus types in both groups. After two doses the seroresponse rate to each type was less with the shorter dose interval. However the difference was not significant (P = 0.15) in the sample size studied. Such responses differ markedly from those seen in developing countries, where four or more doses of vaccine may fail to provide complete protection. Differences other than dosage interval must contribute to those failures.

Antibodies, Viral↗

PubMed1994

The white blood cell response to splenectomy and bacteraemia.

The aim of this study was to determine the relationship of the white blood cell (WBC) count to bacteraemia, and the risk of bacteraemia after splenectomy. The case series study was carried out at the Vanderbilt University Level I Trauma Center, and included 11,870 consecutive trauma admissions: 258 required a splenectomy (191) or splenorrhaphy (67). Bacteraemia was defined as the presence of a positive blood culture. Statistical analysis included ANOVA, the non-parametric Kruskal-Wallis test and logistical regression. Forty-two (22 per cent) of the splenectomy patients had positive blood cultures, while only six (9 per cent) of the splenorrhaphy patients had positive cultures. For the group of patients requiring a splenectomy, the mean WBC count was higher and more persistent in patients with bacteraemia. Logistical regression demonstrated that the type of surgery does not significantly correlate with bacteraemia after accounting for severity of injury (TRISS). The study conclusions were as follows (1) for the group of patients with bacteraemia after splenectomy, the peak WBC count was higher and more persistent than that which occurred in the group of patients without bacteraemia after splenectomy; (2) the WBC count cannot be used to predict bacteraemia for an individual patient, but a WBC count greater than 20,000 after 10 days should initiate a vigorous search for infection; (3) the severity of injury (and not splenectomy/splenorrhaphy) accounted for the increased risk of bacteraemia in population studied.

Adolescent↗

PubMed1994

The Tyr-MIF-1 family of peptides.

A review of research on the Tyr-MIF-1 family of peptides is presented with emphasis on Tyr-MIF-1 and its structure, passage through the blood-brain barrier, and both opiate antagonist and agonist properties. Family members MIF-1, Tyr-W-MIF-1 and Tyr-K-MIF-1 are also included.

Animals↗

PubMed1994

The effects of acute hypercortisolemia on beta-hydroxybutyrate and glycerol metabolism during insulin deficiency.

The present study was undertaken to determine whether an acute physiologic rise in plasma cortisol during selective insulin deficiency would have significant effects on glycerol and beta-hydroxybutyrate metabolism in conscious overnight-fasted dogs. Each experiment consisted of a two hour dye equilibration period, a 40 minute basal period, and a 3 hour experimental period. A continuous infusion of indocyanine green dye for blood flow estimation was initiated at the start of the equilibration period and continued throughout the experiment. In both of two protocols selective insulin deficiency was created during the experimental period by infusing somatostatin peripherally (0.8 microgram/kg-min) with basal replacement of glucagon intraportally (0.65 ng/kg-min). In the test protocol (CORTISOL, n = 5), 3.0 micrograms/kg-min of hydrocortisone was infused during the experimental period. In the control protocol (SALINE, n = 5), saline was infused. Net hepatic balances were determined using the (A-V) difference technique. During selective insulin deficiency alone (SALINE), the arterial blood glycerol level increased from 81 +/- 19 to 140 +/- 11 microM (p < 0.01) and net hepatic glycerol uptake (NHGlyU) tended to increase from 2.3 +/- 0.3 to 3.3 +/- 0.6 mumol/kg-min (0.05 < 0.1). The arterial plasma free fatty acid (FFA) level remained unchanged at 1041 +/- 35 microM. The arterial beta-hydroxybutyrate (BHOB) level increased slightly from 21 +/- 4 to 29 +/- 5 microM while net hepatic beta-hydroxybutyrate production (NHBP) remained unchanged (1.0 +/- 0.2 mumol/kg-min). During acute hypercortisolemia with selective insulin deficiency (CORTISOL), similar changes occurred in the arterial blood glycerol level and net hepatic glycerol uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗

PubMed1994

Comparison of live attenuated and inactivated influenza vaccines in cystic fibrosis patients and their families: results of a 3-year study.

Forty-one cystic fibrosis (CF) patients and 89 family members were immunized in a double-blind randomized 3-year trial with either intranasal live cold-adapted (ca) influenza A vaccine or the recommended intramuscular trivalent inactivated (triv) influenza vaccine. Local, respiratory, and systemic symptoms after vaccine were infrequent and did not differ between vaccine groups. CF patients did not differ from family members in immune response to either vaccine. Although antibody responses tended to be higher after triv vaccine, > or = 85% of subjects had mean hemagglutination inhibition antibody titers > or = 1:32 to influenza H1N1 and H3N2 after the first dose of either vaccine. Infection with influenza H3N2 viruses circulating during this study occurred with comparable low frequency in CF patients after ca (14 infections/100 subject-years of observation) or triv vaccine (10 infections/100 subject-years of observation). Influenza A ca vaccines appear to be safe, immunogenic alternatives to influenza A inactivated vaccines for CF patients and their families.

Adolescent↗

PubMed1994

Tetravalent rhesus rotavirus vaccine in young infants.

A study of a tetravalent live oral rhesus rotavirus vaccine was conducted in 26 healthy infants 6-22 weeks of age to evaluate safety, viral shedding, and immunogenicity in a double-blind, placebo-controlled fashion. The tetravalent rhesus rotavirus vaccine (RRV-TV) contained equal amounts of RRV (serotype 3) and the VP7 reassortants DxRRV (serotype 1), DS1xRRV (serotype 2), and ST3xRRV (serotype 4). RRV-TV was highly infectious; 16 of 18 recipients shed virus. However, the recovered virus was almost exclusively the parent rhesus strain, RRV. Humoral immune responses were largely limited to the RRV strain. The most consistent response, seen in 14 of 18 vaccines, was an ELISA IgM response to purified RRV. Mucosal antibody responses were not seen. The limited immune response may be a function of age, presence of maternal antibody, timing of the convalescent specimens, or the polyvalent nature of the vaccine.

Administration, Oral↗

PubMed1994

Safety of the blood supply. Surrogate testing and transmission of hepatitis C in patients after massive transfusion.

OBJECTIVE: To define a risk profile for post-transfusion hepatitis C in patients receiving massive transfusion. SUMMARY BACKGROUND DATA: Hepatitis C accounts for more than 90% of post-transfusion hepatitis. METHODS: Two-hundred twenty-one of 8,765 consecutive trauma admissions to a Level I trauma center received more than 20 units of erythrocytes. Sixty-nine survivors had positive viral serologic tests at least 1 year after transfusion. Surrogate testing for hepatitis C using alanine aminotransferase (ALT) levels and antibodies to hepatitis B core antigen (Core) began in October 1986 and January 1987, respectively. Donor blood for group 1 (pre-ALT/Core) was transfused before surrogate screening was introduced. Donor blood for group 2 (post-ALT/Core) was transfused after surrogate screening. RESULTS: Sixty-nine patients received blood products from 4,987 donors (mean, 72.3 units of exposure). No patient tested positive for antibodies to hepatitis B surface antigen, human immunodeficiency virus, or human T-lymphotrophic virus type 1. However 23.2% tested positive for hepatitis C virus (HCV) as measured by a second-generation enzyme immunoassay (HCV 2.0) and a recombinant immunoblot assay (RIBA), and 21.7% tested positive by HCV 1.0. Antibodies to Core were found in 8.7% of patients. The risk for post-transfusion hepatitis C per unit of exposure is estimated to be 1.52% group 1 (pre-ALT/Core) and 0.239% for group 2 (post-ALT/Core). CONCLUSIONS: The introduction of ALT/Core donor screening by a blood bank reduced the incidence of post-transfusion hepatitis C by 84%. The risk for post-transfusion hepatitis C depends on units of exposure, screening techniques, and prevalence of hepatitis C in the donor population. In our community, the risk for post-transfusion hepatitis C is less than 0.2% per unit of exposure. The population of massively transfused patients may serve as our effective resource for monitoring the safety of the blood supply.

Adult↗

PubMed1994

Effects of chronic hypercortisolemia on carbohydrate metabolism during insulin deficiency.

This study was undertaken to further investigate the effect of acute selective insulin deficiency on glycogenolysis and gluconeogenesis occurring during chronic physiological hypercortisolemia in conscious overnight fasted dogs. After an 80-min tracer and dye equilibration period and a 40-min basal period, selective insulin deficiency was created during the 180-min experimental period by infusing somatostatin peripherally (0.8 micrograms.kg-1.min-1) with basal replacement of glucagon intraportally (0.65 ng.kg-1.min-1). In the cortisol group (n = 5), a continuous infusion of hydrocortisone (3.5 micrograms.kg-1.min-1) was begun 5 days before the experiment. In the saline group (n = 5), there was no infusion of cortisol. [3-3H]glucose, [U-14C]alanine, and indocyanine green dye were used to assess glucose production and gluconeogenesis using tracer and arteriovenous difference techniques. During selective insulin deficiency in the saline group, the arterial plasma glucose level (Glc) increased from 109 +/- 2 to 285 +/- 19 mg/dl; glucose production increased from 2.7 +/- 0.2 to 4.5 +/- 0.3 mg.kg-1.min-1. Gluconeogenic efficiency and conversion of alanine to glucose (Conv) increased by 300 +/- 55 and 356 +/- 67%. During selective insulin deficiency in the cortisol group, Glc increased from 117 +/- 3 to 373 +/- 50 mg/dl; glucose production increased from 3.3 +/- 0.5 to 6.9 +/- 0.7 mg.kg-1.min-1. Gluconeogenic efficiency and Conv increased by 268 +/- 41 and 393 +/- 75%, respectively. The maximal glycogenolytic rate increased significantly more in the cortisol group than in the saline group, accounting for the difference in glucose production. These results suggest that, even during chronic hypercortisolemia, acute insulin deficiency has more pronounced effects on glycogenolysis than gluconeogenesis.

Alanine↗

PubMed1994

Energy balance in endurance-trained female cyclists and untrained controls.

Reports of low energy intakes in trained female athletes imply they have an increased energetic efficiency. To address this question, we determined how energy balance was achieved in endurance-trained females cyclists and lean controls (n = 5 in each group). Daily energy expenditure was measured by using standardized physical activity protocols in a whole room calorimeter on two separate occasions: a cycling day and a noncycling day. Energy intake for weight maintenance was determined by a period of controlled feeding 5 days before and the day of each energy expenditure measurement. Energy balance was achieved in the cyclists on the cycling day while they consumed 2,900-3,000 kcal (their usual condition) and in controls on the noncycling day while they consumed 2,100-2,200 kcal (their usual condition). Total daily energy expenditure was not significantly different between the cyclists and controls on the noncycling day with both groups performing similar levels of activity. On the cycling day, daily energy expenditure was significantly greater in the cyclists vs. controls (P < 0.03) as a result of their greater amount of cycling activity. Components of daily energy expenditure, i.e., resting metabolic rate and thermic effect of food and activity (noncycling), were not significantly different between groups. Overall, we found no significant increase in the energetic efficiency of endurance-trained female cyclists compared with controls.

Adolescent↗

PubMed1994

Modification of a whole room indirect calorimeter for measurement of rapid changes in energy expenditure.

Whole room indirect calorimeters are among the most accurate devices for measurement of human energy expenditure and have provided useful data about determinants of total daily energy expenditure. However, a limitation of whole room indirect calorimeters has been the inability to detect acute (usually < 10-15 min) changes in energy expenditure. This precludes using these devices to study the acute effects of food, drugs, or exercise on energy expenditure. We describe modifications made to our whole room indirect calorimeter (respiratory chamber) to allow accurate measurement of energy expenditure over time periods as short as 1 min. The modifications involve changes in the system design and use of signal processing techniques. With these modifications, we can measure energy expenditure in 1-min intervals throughout the day. This allows accurate study of the acute effects of food, exercise, or drugs on energy expenditure in subjects moving freely inside the respiratory chamber. The ability to use respiratory chambers for these types of studies should improve our understanding of how body weight is regulated.

Calorimetry↗