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Biomedical subjects

J C Floyd

Publications and source records attributed to J C Floyd.

At least 19 recordsLinked to original sources
PubMed2001

Delayed vaccination does not improve antibody responses in splenectomized rats experiencing hypovolemic shock.

Delayed vaccination after splenectomy has been shown to increase the antibody response in normotensive rats. The purpose of this experiment was to study the effect of timing of vaccination on antibody responses in rats undergoing splenectomy and experiencing hypovolemic shock. Sixty male Sprague-Dawley rats weighing 250 to 400 g underwent either a sham abdominal surgery or splenectomy after a 30-minute period of controlled hypovolemic shock. All rats then received pneumococcal vaccinations one day, 7 days, or 28 days postoperatively. Antibody levels were determined by enzyme-linked immunosorbent assay 3 weeks after vaccination. Results were compared by analysis of variance. Animals vaccinated one day postoperatively had similar or higher antibody responses than did rats receiving delayed vaccinations after 7 or 28 days. These results were similar for immunoglobulins G and M and more importantly were consistent for animals undergoing splenectomy and sham operations. Delayed vaccinations failed to improve antibody responses when hypovolemic shock preceded splenectomy. We propose that this is the result of complex cytokine responses to hypovolemic shock. These responses have been studied extensively in the setting of septic shock but not in the setting of hypovolemic or hemorrhagic shock.

Animals↗
PubMed1999

Improved antibody responses to delayed pneumococcal vaccination in splenectomized rats.

Pneumococcal vaccination following splenectomy is widely used as prophylaxis against overwhelming postsplenectomy infection. There remains controversy however, over the timing of vaccination. We hypothesized that delaying vaccination would increase the antibody response. Pneumococcal vaccinations were given at designated intervals to rats that had undergone either a sham abdominal surgery or splenectomy. Sixty male Sprague-Dawley rats, 250 to 400 g, were divided into three groups for vaccination: I, 1 day postoperatively; II, 7 days postoperatively; and III, 28 days postsplenectomy/sham. Serum antibody levels were then determined by enzyme-linked immunosorbent assay at 5 and 21 days after vaccination. Immunoglobulin (Ig) levels after delayed vaccination at 1 week postoperatively and 1 month postoperatively were significantly higher than levels from rats vaccinated 1 day postoperatively. IgM levels after vaccinations 1 week and 1 month postoperatively were also significantly higher than levels of rats vaccinated 1 day postoperatively (P < 0.05 for both IgG and IgM). On the basis of these results, we conclude that delaying vaccination after splenectomy enhances antibody responses.

Animals↗
PubMed1998

Flexor tenosynovitis due to Mycobacterium asiaticum.

Mycobacteria other than tuberculosis infections of the hand are seen with increasing frequency. A case of Mycobacterium asiaticum flexor tenosynovitis is described. Successful management included radical flexor tenosynovectomy and therapy with oral minocycline and clarithromycin.

Adult↗
PubMed1993

A prospective study identifying risk factors for discontinuance of insulin pump therapy.

OBJECTIVE: To identify characteristics of adult patients at baseline associated with duration of subsequent, continuous, subcutaneous infusion of insulin treatment (pump therapy) of type I diabetes. RESEARCH DESIGN AND METHODS: For 6 wk, patients followed a standardized conventional therapy and kept a record of insulin dosages, capillary blood glucose concentrations, and symptomatic hypoglycemia. They were then hospitalized. Additional baseline data were obtained and pump therapy was started. Survival analysis was used to determine the relationship between baseline independent variables or risk factors and duration of pump therapy, which is the dependent variable. RESULTS: Of the 68 participants, 33 (49%) terminated pump therapy after an average of 9.9 mo of treatment. Two models (each P < 0.00005) were developed that exhibited a high degree of consistency. Of the 6 variables, 5 were common to both models (HbA1, autonomic neuropathy, mean amplitude of glycemic excursions, frequency of symptoms of hypoglycemia when blood glucose was < 70 mg/dl, and erythema at injection sites). The sixth variable in model 1 (insulin dosage) was replaced in model 2 by a variable, Adult Self-Efficacy for Diabetes, which was obtained on the 33 more recently enrolled patients; this variable related to patient perceptions of self-care behaviors. CONCLUSIONS: We found that, at baseline, the presence of a high concentration of HbA1 and a low estimation by the patient of their ability to treat the disease portend failure of insulin pump therapy as evidenced by its discontinuation. This effect is accentuated when clinical evidence of autonomic neuropathy is observed. These findings offer guidance in selecting patients with type I diabetes for insulin pump therapy.

Adolescent↗
PubMed1990

Feasibility of adjustment of insulin dose by insulin-requiring type II diabetic patients.

Type II (non-insulin-dependent) diabetes accounts for most of the diabetes morbidity and expense, yet no systematic study of the effects of intensification of treatment by such patients who require insulin treatment has been conducted. Therefore, patients were recruited from our diabetes clinics, and by random assignment, experimental and control groups were created (n = 26 and 27, respectively) that were not different at 0 mo regarding 20 demographic, physiological, and treatment variables. Experimental patients practiced an algorithm for adjustment of insulin dosage based on daily prebreakfast capillary blood glucose (CBG) measurements and any symptomatic hypoglycemia. At 2-, 4-, and 6-mo visits, records of CBG measurements were available to the physicians (n = 7), who changed insulin dosages of both groups ad libitum. Feasibility of the experimental treatment is evidenced by study completion by 87% of enrollers, monitoring on 88% of days, accuracy of CBG recording (recorded as percentage of memory meter value, 100.8), weight gain not exceeding that of control subjects, practice of treatment algorithm to effect changes in insulin dosage, modest increase in frequency of mild insulin reactions, and a decrease of glycosylated hemoglobin into the normal range.

Adult↗
PubMed1989

Quality of life activities associated with adherence to insulin infusion pump therapy in the treatment of insulin dependent diabetes mellitus.

The impact of continuous subcutaneous insulin infusion (CSII) pump therapy on patients' activities of daily living and the prevalence of acute complications were examined in order to characterize patients' experience while on CSII, and to ascertain whether any of these factors could be associated with continued use of CSII. Fifty-one of 55 patients (93%) identified as initiating CSII in our medical center patient population completed retrospective surveys; 37 individuals (73%) were still using pumps and 14 individuals (27%) had discontinued pump use. CSII appeared to affect the quality of daily activities only modestly, neither improving nor interfering with many activities to any great degree. Activities associated with greatest improvements were eating, working, traveling, sleeping, and exercising. Results of logit analyses adjusting for duration of pump therapy indicated that the prevalence of six different acute complications (skin infections at the needle site, mild insulin reactions, more severe insulin reactions requiring assistance, hypoglycemic coma, asymptomatic hypoglycemia, and ketoacidosis) was not statistically associated with patients' decisions to continue or to stop CSII. In contrast, significant differences (p less than 0.05) between the groups continuing and discontinuing CSII were found in 11 of 18 activities of daily living. In general, patients continuing CSII, in contrast to those discontinuing CSII, found that many of their activities were improved significantly during pump therapy. There were few differences between groups in the degree to which CSII was perceived to interfere with daily activities. However, those continuing CSII found it significantly less necessary to take the pump off while doing some activities than did those discontinuing CSII.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1986

Multiple endocrine neoplasia type I: assessment of laboratory tests to screen for the gene in a large kindred.

We measured multiple components of serum or plasma in 221 members of a kindred with familial multiple endocrine neoplasia type 1 (FMEN1). The kindred showed typical features of FMEN1; the FMEN1 gene could be traced through 7 generations with 74 members identifiable as gene carriers. Between family screening in 1981 and completion of our study in 1985, we identified 16 previously unscreened members as carriers of the FMEN1 gene. The earliest age at diagnosis of FMEN1 was 17. The tests with the greatest yield of abnormal results among carriers of the FMEN1 gene were albumin-adjusted calcium, PTH, gastrin, and (in females) prolactin. The following tests provided little or no use in identifying carriers: prolactin (in males), pancreatic polypeptide, glucagon, glicentin, insulin, growth hormone, motilin, and somatostatin. Primary hyperparathyroidism was the commonest expression of the FMEN1 gene; the gene penetrance for this trait increased from near 0% before age 15 to near 100% after age 40. It appeared prior to development of serious morbidity from hypergastrinemia or hyperprolactinemia. All 42 co-operating members who were alive and expressing the FMEN1 gene in 1984 showed active or treated primary hyperparathyroidism. Primary hypergastrinemia had a prevalence below half of that for primary hyperparathyroidism at all ages and was not diagnosed in the absence of primary hyperparathyroidism. Primary hyperprolactinemia was still less prevalent than primary hypergastrinemia. It was limited almost exclusively to females.

Adolescent↗
PubMed1983

Secretion of pancreatic polypeptide in man in response to beef ingestion is mediated in part by an extravagal cholinergic mechanism.

The effect of atropine, a muscarinic cholinergic blocking agent, on the response of plasma pancreatic polypeptide (hPP) to the ingestion of beef was investigated. Six healthy subjects ingested 250 g broiled ground beef on three occasions. After beef ingestion alone, the expected biphasic plasma hPP response was observed. On the two other occasions atropine (intravenous bolus followed by infusion) was begun either at 4 or 60 min after the beginning of beef ingestion so as to coincide with the early (first) and late (second) phases of hPP response to beef ingestion. On both occasions plasma hPP concentrations returned rapidly to baseline. Mean integrated incremental hPP responses in the absence of atropine were 9.1 +/- 3.4 ng min ml-1 for the first phase (0-40 min) and 29.7 +/- 5.7 ng min ml-1 for the second phase (60-180 min); with atropine at 4 min, respective responses were 0.8 +/- 0.9 and -1.0 +/- 1.3 ng min ml,-1 and with atropine at 60 min they were 10.6 +/- 5.0 and 1.3 +/- 1.6 ng min ml.-1 After atropine administration, the half-time of disappearance of hPP from the circulation was 4-6 min, suggesting the complete cessation of stimulated hPP secretion. We conclude that the mechanisms of both the early and late phases of beef meal-stimulated release of hPP involve muscarinic cholinergic-neural transmission. The portion of the second (late) phase response which has been shown to persist after truncal vagotomy must be mediated by a cholinergic mechanism which is extravagal in character.

Adult↗
PubMed1983

Sex difference in the sensitivity of the human pancreatic polypeptide cell to autonomic nervous stimulation in man.

We have examined the plasma human pancreatic polypeptide (hPP) response to beta-adrenergic (infusion of epinephrine-phentolamine), vagal cholinergic, (insulin-hypoglycemia), and extravagal cholinergic (secretion infusion) stimulation in healthy, nonobese, age-matched males and females. beta-Adrenergic stimulation caused a rise in plasma hPP concentration in males that was 6 times that of females, whereas there were no differences between the sexes in the mean responses of pulse rate, systolic and diastolic blood pressure, or in plasma concentrations of glucose, insulin, and glucagon. Extravagal cholinergic stimulation caused increases of hPP secretion that were similar in males and females. Insulin-induced hypoglycemia was the most efficacious stimulus, and caused a similar rise in hPP response in males and females. Thus, in males there is greater sensitivity of the hPP cell to beta-adrenergic stimulation than females. The plasma hPP responses appear to be a more sensitive, discriminating index of adrenergic autonomic function than cardiovascular and other pancreatic hormonal responses.

Autonomic Nervous System↗
PubMed1982

Glucose tolerance in two unacculturated Indian tribes of Brazil.

Plasma levels of glucose, insulin, growth hormone, and pancreatic polypeptide in response to a standard oral glucose load were studied in the Yanomama and the Marubo, two relatively unacculturated Amerindian tribes of the Brazilian Amazon. The findings in the two tribes differed significantly from each other and in the degree of deviation from control subjects. The average responses in both tribes differed significantly from those of age- and sex-matched Caucasoid control subjects studied in Ann Arbor, Michigan; however, of the two tribes, the Marubo, the more acculturated group, resembled the controls more closely. Plasma concentrations of glucose and the hormones at three time points (fasting, 1 h, 2 h) were compared by means of a multivariate analysis. When the Marubo were compared with the control subjects, the only highly significant difference was in the plasma glucose concentrations (all three points were higher in the Marubo); however, the Yanomama differed significantly from the control subjects with respect to all four plasma indicators (p less than 0.05). Unlike the Marubo, the Yanomama showed no significant rise in plasma glucose at 1 h and no decrease at 2 h. Neither tribe exhibited the bimodality of the 2 h glucose value characteristic of acculturated Amerindians, such as the Pima, but the samples studied were small.

Adolescent↗
PubMed1982

Growth of high aflatoxin B2 mutants on defined and complex media and with ethoxyquin.

The major naturally occurring aflatoxins are B1, B2, G1, and G2. A precursor-product relationship between B1 and the other toxins has been assumed by many workers, but experimental data are conflicting. Four independent reports, of mutants which produce aflatoxin B2, provide genetic evidence supporting an alternate origin for B2. Five high aflatoxin B2 mutants were obtained and grown in defined and complex liquid media and on a solid complex medium in order to determine the stability of the high B2 phenotype on different substrates and to define optimal levels of production. All the high B2 strains tested produced some aflatoxin yields were quite variable. The highest production was on complex liquid medium containing yeast extract. It was not possible to confirm reports that the antioxidant ethoxyquin was an inhibitor of G aflatoxins.

Aflatoxins↗
PubMed1981

The effect of treatment of type 2 (insulin independent) diabetes mellitus on plasma concentrations of pancreatic polypeptide and glucagon.

The effect of the control of diabetes with diet and insulin upon plasma levels of human pancreatic polypeptide and glucagon was determined in eight patients with Type 2 (insulin independent) diabetes mellitus. The mean +/- SEM fasting plasma glucose was 15.9 +/- 1.3 mmol/l for 5 days of diet treatment and 5.9 +/- 0.4 mmol/l for the last 5 days of treatment with diet plus insulin (p less than 0.0001); corresponding fasting plasma pancreatic polypeptide levels were 328 +/- 97 and 247 +/- 71 pg/ml (p less than 0.05) and immunoreactive glucagon levels were 95 +/- 11 and 62 +/- 6 pg/ml (p less than 0.005). Cooked ground beef was administered on the first day of diet treatment and on the last day of treatment with diet plus insulin; mean maximal rise of pancreatic polypeptide, and total and incremental plasma pancreatic polypeptide response areas were significantly lower following treatment (p less than 0.01), as was total area for immunoreactive glucagon (p less than 0.05). Normalisation of fasting plasma glucose by short-term treatment with diet plus insulin is associated with decreases in basal and stimulated secretory activity of the pancreatic polypeptide cells in insulin independent diabetes mellitus.

Adult↗
PubMed1980

The effect of adrenergic receptor blockade on the exercise-induced rise in pancreatic polypeptide in man.

The effect of adrenergic receptor-blocking agents upon plasma levels of human pancreatic polypeptide (hPP), human GH (hGH), immunoreactive insulin, and glucose during graded submaximal exercise was ascertained in six healthy nonobese males. Subjects exercised from 0--27 min on a motor-driven treadmill and received infusions from -10 to 40 min of either 1) saline, 2) saline plus phentolamine (0.5 mg/min; alpha-adrenergic blockade), or 3) propranolol (3 mg) from -10 to -5 min, followed by saline plus propranolol (0.08 mg/min; beta-adrenergic blockade). During saline-exercise, mean plasma hPP rose from a mean (+/-SE) basal level of 45 +/- 11 to 149 +/- 51 pg/ml at 27 min, whereas with phentolamine-exercise, the maximal level reached by mean plasma hPP (305 +/- 28 pg/ml) was significantly greater than that with saline (P less than 0.05). During propranolol-exercise, mean plasma hPP did not rise significantly above the basal level. The incremental area under the hPP curve for phentolamine-exercise also was significantly greater than that for saline-exercise or propranolol-exercise. The changes in plasma hGH during and after saline-exercise correlated with those of hPP, but the effects of phentolamine and propranolol upon exercise-induced increases in hGH were opposite to the effects upon hPP. The exercise-induced fall in immunoreactive insulin was accentuated with propranolol and abolished with phentolamine. It is concluded that 1) submaximal exercise stimulates secretion of hPP and hGH, 2) adrnergic mechanisms participate in exercise-induced increased secretion of hPP (beta-adrenergic stimulation augments secretion and alpha-adrenergic stimulation inhibits secretion), and 3) adrenergic effects which modulate exercise-induced secretion of hPP and insulin are in parallel but are opposite to those that modulate the secretion of hGH.

Adult↗