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Biomedical subjects

C L Taylor

Publications and source records attributed to C L Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1991

Regional cerebral blood flow following resuscitation from hemorrhagic shock with hypertonic saline. Influence of a subdural mass.

After severe hemorrhage, hypertonic saline restores systemic hemodynamics and decreases intracranial pressure (ICP), but its effects on regional cerebral blood flow (rCBF) when used for resuscitation of experimental animals with combined shock and intracranial hypertension have not been reported. We compared rCBF changes (by radiolabeled microsphere technique) after resuscitation from hemorrhage with either 0.8 or 7.2% saline in animals with and without a right hemispheric subdural mass. We studied 24 mongrel dogs anesthetized with 0.5% halothane and 60% nitrous oxide. In group 1 (n = 12), hemorrhage reduced mean arterial pressure (MAP) to 45 mmHg for 30 min. In group 2 (n = 12), ICP was increased and maintained constant at 15 mmHg, whereas hemorrhage reduced MAP to 55 mmHg for 30 min (cerebral perfusion pressure [CPP] approximately 40 mmHg in each group). After the 30-min shock period, 6 animals in each group received one of two randomly assigned resuscitation fluids over a 5-min interval: 1) 7.2% hypertonic saline (HS; sodium 1,232 mEq.l-1, volume 6.0 ml.kg-1); or 2) 0.8% isotonic saline (SAL; sodium 137 mEq.l-1, volume 54 ml.kg-1). Once fluid resuscitation began, ICP was permitted to vary independently in both groups. Data were collected at baseline (before subdural balloon inflation in group 2), midway through the shock interval (T15), immediately after fluid infusion (T35), and 60 and 90 min later (T95, T155). In groups 1 and 2, ICP was significantly less in animals resuscitated with HS compared to those receiving SAL (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Small-volume resuscitation from hemorrhagic shock in dogs: effects on systemic hemodynamics and systemic blood flow.

BACKGROUND AND METHODS: This study compared canine systemic hemodynamics and organ blood flow (radioactive microsphere technique) after resuscitation with 0.8% saline (Na+ 137 mEq/L), 7.2% hypertonic saline (Na+ 1233 mEq/L), 20% hydroxyethyl starch in 0.8% saline, or 20% hydroxyethyl starch in 7.2% saline, each in a volume approximating 15% of shed blood volume. Twenty-four endotracheally intubated mongrel dogs (18 to 24 kg) underwent a 30-min period of hemorrhagic shock, from time 0 to 30 min into the shock period, followed by fluid resuscitation. Data were collected at baseline, 15 min into the shock period, immediately after fluid infusion, 5 min after the beginning of resuscitation, and at 60-min intervals for 2 hr, (65 min after the beginning of resuscitation, and 125 min after the beginning of resuscitation). The animals received one of four randomly assigned iv resuscitation fluids: saline (54 mL/kg), hypertonic saline (6.0 mL/kg), hydroxyethel starch (6.0 mL/kg) or hypertonic saline/hydroxyethyl starch (6.0 mL/kg). RESULTS: Mean arterial pressure increased in all groups after resuscitation. Cardiac output increased with resuscitation in all groups, exceeding baseline in the saline and hypertonic saline/hydroxyethyl starch groups (p less than .05 compared with hypertonic saline or hydroxyethyl starch). Sixty-five minutes after the beginning of resuscitation, cardiac output was significantly (p less than .05) greater in either of the two colloid-containing groups than in the hypertonic saline group. After resuscitation, hypertonic saline and hydroxyethyl starch produced minimal improvements in hepatic arterial flow, hypertonic saline/hydroxyethyl starch increased hepatic arterial flow to near baseline levels, and saline markedly increased hepatic arterial flow to levels exceeding baseline (p less than .05, saline vs. hydroxyethyl starch). One hundred twenty-five minutes after the beginning of resuscitation, hepatic arterial flow had decreased in all groups; hepatic arterial flow in the hypertonic saline group had decreased to levels comparable with those during shock. Myocardial, renal, and brain blood flow were not significantly different between groups. CONCLUSIONS: Small-volume resuscitation with the combination of hypertonic saline/hydroxyethyl starch is comparable with much larger volumes of 0.8% saline, and is equal to hypertonic saline or hydroxyethyl starch in the ability to restore and sustain BP and improve organ blood flow after resuscitation from hemorrhagic shock.

Animals↗
PubMed1991

Cerebrovascular effects of small volume resuscitation from hemorrhagic shock: comparison of hypertonic saline and concentrated hydroxyethyl starch in dogs.

To determine if hypertonic and hyperoncotic resuscitation solutions exerted comparable effects on cerebral hemodynamics following hemorrhagic shock, we compared randomly assigned, equal volumes (6.0 ml/kg) of hypertonic (7.2%) saline (HS) and hyperoncotic (20%) hydroxyethyl starch (HES) for resuscitation from acute experimental hemorrhage in 12 anesthetized dogs. Regional cerebral blood flow (radiolabeled microspheres), intracranial pressure (cisternal catheter), and systemic hemodynamics were recorded. Rapid hemorrhage reduced the mean arterial pressure to 45 mm Hg for 30 min. Resuscitation fluids were infused over 5 min. Both fluids restored mean arterial pressure and cardiac output equally. However, at 60 min following resuscitation, cardiac output decreased in the HS group in comparison to the HES group (1.7 +/- 0.1 vs. 3.1 +/- 0.2 L/min, p <0.05). Cardiac output rapidly declined, however, in the HS group in comparison to the HES group (p <0.05 60 min following resuscitation). Intracranial pressure and cerebral perfusion pressure were similar at all intervals. Regional cerebral blood flow was similar following both fluids. Neither fluid restored cerebral oxygen transport to baseline values. Based on these data, the authors conclude that, following severe hemorrhagic shock of brief duration, systemic and cerebral hemodynamic values are restored equally well by highly concentrated colloid or by hypertonic saline, although hypertonic saline only transiently improves cardiac output.

Journal Article↗
PubMed1991

Binding of S protein by Neisseria gonorrhoeae and potential role in invasion.

An agglutination assay was used to examine the binding of purified human S protein (vitronectin, serum spreading factor) to 201 clinical isolates of Neisseria gonorrhoeae. Strains belonging to the protein IA serovars were significantly (P less than 0.001) more reactive in agglutination tests with human S protein and were more serum resistant than strains belonging to the protein IB serovars. The strains from patients with disseminated infections belonged predominantly to the IA serovar (19 of 23) and, with the exception of IA-4 and certain IB serovars, avidly agglutinated with S protein. The serovar IA-4 and IB strains isolated from joint or cerebrospinal fluid failed to agglutinate with S protein and appeared to be less serum resistant than most other IA isolates. Cysteine hydrochloride or 2-mercaptoethanol inhibited agglutination of S protein and a more than twofold increase in resistance to killing by fresh human serum following preincubation with S protein; the serum-sensitive parent strain did not agglutinate S protein, and serum resistance was not increased following preincubation with this protein. Binding of S protein by gonococci may represent a novel pathogenic mechanism that can contribute to serum resistance.

Agglutination↗
PubMed1991

Cerebral blood flow decreases with time whereas cerebral oxygen consumption remains stable during hypothermic cardiopulmonary bypass in humans.

Recent investigations demonstrate that cerebral blood flow (CBF) progressively declines during hypothermic, nonpulsatile cardiopulmonary bypass (CPB). If CBF declines because of brain cooling, the cerebral metabolic rate for oxygen (CMRO2) should decline in parallel with the reduction in CBF. Therefore we studied the response of CBF, the cerebral arteriovenous oxygen content difference (A-VDcereO2) and CMRO2 as a function of the duration of CPB in humans. To do this, we compared the cerebrovascular response to changes in the PaCO2. Because sequential CBF measurements using xenon 133 (133Xe) clearance must be separated by 15-25 min, we hypothesized that a time-dependent decline in CBF would accentuate the CBF reduction caused by a decrease in PaCO2, but would blunt the CBF increase associated with a rise in PaCO2. We measured CBF in 25 patients and calculated the cerebral arteriovenous oxygen content difference using radial arterial and jugular venous bulb blood samples. Patients were randomly assigned to management within either a lower (32-48 mm Hg) or higher (50-71 mm Hg) range of PaCO2 uncorrected for temperature. Each patient underwent two randomly ordered sets of measurements, one at a lower PaCO2 and the other at a higher PaCO2 within the respective ranges. Cerebrovascular responsiveness to changes in PaCO2 was calculated as specific reactivity (SR), the change in CBF divided by the change in PaCO2, expressed in mL.100 g-1.min-1.mm Hg-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Hypertonic/hyperoncotic fluid resuscitation after hemorrhagic shock in dogs.

We compared canine systemic and cerebral hemodynamics after resuscitation from hemorrhagic shock with 4 mL/kg (a volume approximating 12% of shed blood volume) of 7.2% saline (HS; 1233 mEq/L sodium), 20% hydroxyethyl starch (HES) in 0.8% saline, or a combination fluid consisting of 20% hydroxyethyl starch in 7.2% saline (HS/HES). Eighteen endotracheally intubated mongrel dogs (18-24 kg) were ventilated to maintain normocarbia with 0.5% halothane in nitrous oxide and oxygen (60:40). After a 30-min period of hemorrhagic shock (mean arterial blood pressure = 40 mm Hg), extending from time T0 to T30, animals received one of three randomly assigned intravenous resuscitation fluids: HS, HES, or HS/HES. Data were collected at baseline, at the beginning and end of the shock period (T0 and T30), immediately after fluid infusion (T35), and at 60-min intervals for 2 h (T95, T155). After resuscitation, mean arterial blood pressure and cardiac output increased similarly in all groups, but failed to return to baseline. Intracranial pressure decreased during shock and increased slightly, immediately after resuscitation in all groups. During shock, cerebral blood flow (cerebral venous outflow method) declined in all groups. After resuscitation, cerebral blood flow increased, exceeding baseline in the HS and HS/HES groups but remaining low in the HES group (P less than 0.05 HS vs HES at T35). We conclude that small-volume resuscitation (4 mL/kg) with HS, HS/HES, or HES does not effectively restore or sustain systemic hemodynamics in hemorrhaged dogs. In dogs without intracranial pathology, the effects on cerebral hemodynamics are also comparable, except for transiently greater cerebral blood flow in the HS group in comparison with the HES group.

Animals↗
PubMed1990

Long term propranolol treatment and changes in body weight after myocardial infarction.

OBJECTIVE: To determine the effect of long term propranolol treatment on body weight. DESIGN: Retrospective analysis of data from a placebo controlled randomised double blind clinical trial (the beta blocker heart attack trial). PATIENTS: 3837 Men and women randomised 5-21 days after an acute myocardial infarction to treatment with placebo or propranolol for up to 40 months. Patients were followed up at annual visits. MAIN OUTCOME MEASURE: Changes in body weight. RESULTS: At the first annual visit patients treated with propranolol had gained more weight than those given placebo (mean weight gain 2.3 kg v 1.2 kg respectively, mean difference 1.2 kg (95% confidence interval 0.9 to 1.5]. These group differences remained at the second and third annual visits. The difference in weight gain could not be explained by discrepancies in the use of diuretics or in physical activity and was similar in patients of both sexes and of all ages. CONCLUSION: Long term beta blockade results in a sustained weight gain.

Double-Blind Method↗
PubMed1990

Ileostomy using an interposed ileal segment to function as a 'neocolon'.

A new type of ileostomy was constructed in rats using an interposed ileal (I-I) segment functioning as a neocolon. The effects of this operation in these rats were compared with a control group undergoing conventional ileostomy (I). Rats in the I group lost weight throughout follow-up, whereas rats in the I-I group regained weight and were significantly heavier four weeks after surgery. Transit time from the stomach to the stoma was significantly prolonged in the I-I group (187 +/- 29 minutes) when compared with the I group (141 +/- 17 minutes, P less than 0.01). Serum analysis revealed no significant differences in total protein, lipids, electrolytes (Na, Cl, CO2), and osmolarity between the groups. Biliary bile salt concentration, normalized bile flow, and normalized bile acid output in the I-I group were not different from those in unoperated control rats, suggesting unimpaired bile acid metabolism. These data suggest this operative procedure has the beneficial effects of slowing intestinal transit and promoting postoperative recovery without impairing distal ileal function.

Animals↗
PubMed1990

Serial Doppler echocardiographic follow-up of left ventricular diastolic function in cardiac amyloidosis.

A spectrum of left ventricular diastolic filling abnormalities noted on Doppler echocardiography has been demonstrated in patients with cardiac amyloidosis. To determine how these filling abnormalities evolve over time and the significance of any change, serial pulsed wave Doppler studies of left ventricular inflow were performed over 12.6 +/- 4.9 months in 41 consecutive patients (36 men and 15 women, mean age 59 +/- 11 years) with typical two-dimensional echocardiographic features of cardiac involvement. The measurements were peak left ventricular inflow in early diastole (E) and atrial contraction (A) velocities, E/A ratio, deceleration time and isovolumetric relaxation time. Patients were classified by mean left ventricular wall thickness into an early group (less than 15 mm) of 24 patients and an advanced group (greater than or equal to 15 mm) of 17 patients. The total group showed an increased E/A ratio (1.7 +/- 0.9 versus 1.4 +/- 0.9, p = 0.009) and decreased deceleration time (164 +/- 57 versus 174 +/- 51 ms, p = 0.11) at follow-up compared with baseline study. The early group showed significant changes in the E/A ratio (1.6 +/- 1.0 versus 1.2 +/- 0.7, p = 0.001) between the two studies. Seven patients (29%) in the early group showed a change from an abnormal relaxation or "normal" pattern to one of restriction, coincident with increased symptoms in six of these patients. Fifteen (88%) of the 17 patients in the advanced group did not show significant changes in the measures during the follow-up study, but these patients already showed a restrictive pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloidosis↗
PubMed1990

Progression of aortic stenosis in adults: new appraisal using Doppler echocardiography.

This study examined progression of aortic stenosis (AS) as assessed by Doppler echocardiography. One hundred twelve consecutive adult patients had calcific AS and underwent three examinations during a mean 25-month period (range 7 to 54 months). At the time of entry into the study, mean values for initial peak aortic velocity and ejection fraction (EF) were 2.9 +/- 0.7 m/sec and 63 +/- 10%, respectively; 52% of the patients were symptomatic. At the third examination the percentage of symptomatic patients increased to 65% (p = 0.0039 compared to baseline values), and the aortic peak velocity increased to 3.3 +/- 0.8 m/sec (p less than 0.001). Age, sex, and EF were not predictors of progression. Documented coronary artery disease (in 57 patients) did not affect progression, and neither did the aortic peak velocity at the time of entry into the study. Thirty-eight patients reported an increase in symptoms from the first to third examination, and their rate of progression was significantly different from that of the rest of the population: 0.33 +/- 0.50 m/sec/yr compared to 0.18 +/- 0.26 m/sec/yr (p less than 0.03).

Aged↗
PubMed1989

Factors associated with the recommendation for endocarditis prophylaxis in mitral value prolapse.

We conducted a population-based study to examine the association between clinical and Doppler echocardiographic characteristics and physicians' recommendation for endocarditis prophylaxis. Of 127 consecutive Olmsted County, Minnesota, residents with newly documented isolated mitral valve prolapse, endocarditis prophylaxis was recommended three to four times more often in patients under 40 years compared with those more than 60 years of age. Using multiple logistic regression, for every 10-year increment in age, there was a 30% independent reduction in recommendations for endocarditis prophylaxis. Doppler evidence of mitral regurgitation was also independently associated with recommendations for endocarditis prophylaxis. Observations from physical examination, including systolic murmur and systolic click, were weakly associated with endocarditis prophylaxis recommendations. Mitral valve appearance (thickened vs not) was not associated with endocarditis prophylaxis. Although current recommendations for endocarditis prophylaxis and mitral valve prolapse do not address age and Doppler-detected mitral regurgitation, these variables are strongly associated with clinical decisions. Prospective, longitudinal, population-based studies are needed to define endocarditis risk further in subgroups with mitral valve prolapse to provide a more scientific basis for clinical decision making.

Adult↗
PubMed1989

Utility of color flow imaging for visualizing shunt flow in atrial septal defect.

Color flow imaging provides visualization of intracardiac blood flow. The usefulness of this technique was evaluated in 93 patients with atrial septal defect. Color flow imaging improves the sensitivity of two-dimensional Doppler echocardiography in the diagnosis of atrial septal defect. In addition, it enhances communication between the cardiologist and the cardiovascular surgeon.

Adolescent↗
PubMed1989

Level of agreement between questionnaire measures of alcohol dependence, alcoholism and problem drinking in a sample presenting at a specialist alcohol treatment service.

Two questionnaire measures of the alcohol dependence syndrome, one of alcoholism, and one of alcohol-related problems were compared in a sample of 101 subjects attending a specialist alcohol treatment unit. There was substantial agreement between the two measures of alcohol dependence, and lesser agreement between any other pairing. The measures of alcohol dependence also showed the strongest correlation with reported weekly alcohol consumption. The findings are compared with previous research, and the suitability of the various questionnaires as case-defining instruments in empirical investigations is discussed.

Adult↗
PubMed1988

Role of L3T4+ T cells in host defense against Histoplasma capsulatum.

Cell-mediated immunity is critical in host resistance against the pathogenic fungus Histoplasma capsulatum. To explore the role of L3T4+ T cells in protection of mice against H. capsulatum infection, we examined the effect of in vivo treatment with anti-L3T4 monoclonal antibody (MAb) GK1.5 on the course of murine disseminated histoplasmosis. Treatment with anti-L3T4 antibody caused a profound and selective depletion of L3T4+ T cells that was associated with a significant increase in the number of H. capsulatum CFU recovered from the spleens of mice infected for 1 week. In addition, none of the infected mice treated with MAb GK1.5 survived a sublethal challenge with H. capsulatum yeasts. Histopathological examination of spleens from mice infected for 1 week revealed the presence of granulomatous inflammation in mice depleted of L3T4+ T cells and in infected controls. However, silver stains demonstrated that spleens of infected mice given MAb GK1.5 contained a greater number of yeasts than did spleens from infected controls. MAb GK1.5 did not cause reactivation of infection when administered for 2 weeks beginning 4 weeks after inoculation of Histoplasma yeasts. MAb GK1.5 did not alter the functional properties of murine macrophages as measured by antigen presentation, production of interleukin-1 in response to lipopolysaccharide, and phagocytosis of H. capsulatum yeasts. These results suggest that the L3T4+ T-cell subset is an essential constituent of the cell-mediated immune defense against H. capsulatum infection.

Animals↗
PubMed1986

Prospective study of alcohol-related admissions in an inner-city hospital.

Of 2598 acute admissions to the intensive therapy unit and medical, surgical, orthopaedic, and casualty wards of a general hospital in London, 313 (12%) were definitely alcohol related. Over half (163) the patients concerned were aged between 14 and 40 and 70% (219) were male. The proportion of alcohol-related admissions varied from 7.2% for a general surgical ward up to 26.3% for the casualty overnight observation ward. Substantially higher than average rates of alcohol-related admission were seen in Irish, Scottish, and Polish patients. Of the 23 deaths in the beds under scrutiny in patients aged 17-60 years, 9 were directly attributable to acute or chronic alcohol abuse.

Adult↗
PubMed1986

Human monoclonal antibody. Construction of stable clones reactive with human breast cancer.

A human clone was derived from fusion of a malignant cell line (Ball-1) and peripheral blood lymphocytes from a breast cancer patient in long-term remission. This clone, JDB1, was shown to be a genetically identifiable hybrid, expressing chromosomes unique to each of the parental cell types. The JDB1 clone produces IgG/lambda molecules which are extremely reactive with breast tumor cells, but do not bind to normal breast tissue or other types of malignant tissue. This hybrid was constructed without using the commonly accepted fusion technology which employs 8-azoguanine resistant HAT sensitive malignant fusion partners. Rather a selective fusion procedure was used in which a choice of the most efficient and effective malignant partner could be made prior to fusion. This approach was accompanied by stringent selection of patients as lymphocyte donors. This method has allowed for stable and vigorous growth of clones with a near constant amount of specific immunoglobulin production and a normal diploid chromosome number for over 3 years.

Antibodies, Monoclonal↗
PubMed1986

Modulation of cellular immune responses in mice with disseminated histoplasmosis by recombinant interleukin-2.

Depression of the cellular immune responses in mice with disseminated histoplasmosis is associated with deficient production of interleukin-2 (IL-2) by splenocytes. Therefore, we examined whether a highly purified preparation of IL-2, recombinant human IL-2 (rIL-2), could modify the cellular immune responses in infected mice and whether this lymphokine could alter the severity of histoplasmosis in animals. Exogenous rIL-2, at concentrations of up to 1,000 U/ml, failed to augment the proliferative responses to concanavalin A by unfractionated splenocytes or splenic T cells from mice infected for 1 week. In addition, rIL-2 did not modulate the plaque-forming cell response to sheep erythrocytes by splenocytes from these same mice. However, at week 3, rIL-2 in concentrations ranging from 10 to 1,000 U/ml considerably augmented the proliferative response to concanavalin A and plaque-forming cell response to sheep erythrocytes by splenocytes from infected mice. Kinetics studies demonstrated that rIL-2 exerted maximal immunoregulatory activity when added on day 0 or 1 to cultures of splenocytes. In vivo administration of rIL-2, 200 to 20,000 U/day, for 10 days to normal and 3-week-infected mice did not alter the proliferative activity of splenocytes to concanavalin A; 200,000 U of rIL-2 per day actually depressed the proliferative responses of splenocytes from normal and infected mice. In vivo, rIL-2 did not modify delayed-type hypersensitivity responses to sheep erythrocytes or to histoplasmin by normal and infected mice. Moreover, treatment with rIL-2 in vivo did not reduce the number of Histoplasma CFU in spleens of mice. Thus, despite the immunoenhancing effect of rIL-2 in vitro, this lymphokine failed to exert similar effects in vivo.

Animals↗