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Biomedical subjects

W Lee

Publications and source records attributed to W Lee.

At least 343 records · Page 19Linked to original sources
PubMed1988

Effects of somatostatin and pancreatic polypeptide on exocrine and endocrine pancreas in the rats.

The effects of somatostatin-14 (SS) and rat pancreatic polypeptide (rPP) on endocrine and exocrine functions of the pancreas, stimulated by 40 ng/kg cholecystokinin octapeptide during continuous infusion of 1 U/kg/h secretin, were investigated in the rat, in vivo. Protein output in the pancreatic juice and integrated insulin (IRI) secretion were inhibited, in a dose related fashion, by continuous infusion of SS, in doses of 0.5, 5 and 50 micrograms/100g/h. On the other hand, bicarbonate and volume output were not inhibited by SS. The rPP significantly inhibited not only the protein output but also the bicarbonate and volume output of the pancreatic juice in doses of 0.1 and 1 microgram/100g/h. Integrated IRI secretion was inhibited significantly by rPP, but the inhibition of IRI secretion was much greater in the portal than in the jugular vein. Plasma SS and rPP concentrations showed physiological ranges during infusion of doses of 0.5 and 0.1 microgram/100g/h of SS and rPP, respectively. Therefore, there was a marked difference between the inhibition by rPP and that by SS on the exocrine and endocrine pancreas. These observations suggest that SS and PP may play a physiological role in the pancreas and that their effects on the pancreas relate to different mechanisms.

Animals↗
PubMed1988

The clinical and pathophysiologic implications of pain, ST abnormalities, and scintigraphic changes induced during dipyridamole infusion: their relationships to the peripheral hemodynamic response.

In order to determine their significance during dipyridamole perfusion scintigraphy, symptomatic, ECG, and scintigraphic findings were related to each other, to the hemodynamic response, and to angiographic findings in 73 consecutive patients having coronary angiography within 3 months of scintigraphy. The group having induced "cardiac" pain differed from the group without induced pain only in their higher incidence of induced ischemic ST changes, the "marked" hemodynamic response, and their lower incidence of an "absent" hemodynamic response (all p less than 0.01). Induced ST depression was found only in patients with coronary disease. In this population, dipyridamole-induced pain was a moderately specific marker and induced ST abnormalities a more highly specific marker for coronary disease. However, both were insensitive for coronary disease diagnosis. If induced pain or ST abnormalities in the presence of significant coronary disease were accepted as indicators of ischemia, then scintigraphic abnormalities appeared to be produced by dipyridamole in roughly equal incidence by ischemic and nonischemic mechanisms. Induced ischemia related frequently to an exaggerated hypotensive response with no change in double product, suggesting its cause to be an induced increase in myocardial oxygen demand. Dipyridamole-induced image defects were noted even in the absence of a peripheral hemodynamic response. This indicates that the peripheral response does not always correlate with its central coronary effect and an absent peripheral hemodynamic response does not necessarily invalidate scintigraphic results.

Angina Pectoris↗
PubMed1988

Noninvasive maternal stroke volume and cardiac output determinations by pulsed Doppler echocardiography.

Sixteen obstetric patients with pulmonary artery catheters were studied by two-dimensional and pulsed Doppler echocardiography to compare prospectively pulsed Doppler-and thermodilution-derived estimations of left ventricular stroke volume and cardiac output. Systolic aortic flow velocity waveforms were obtained by pulsed Doppler ultrasound from the apical five-chamber echocardiographic window. Aortic diameters were obtained by two-dimensional echocardiography from the left parasternal long axis view. The mean (+/- SEM) aortic diameter averaged 2.1 +/- 0.1 cm, with a mean calculated aortic valve area of 3.6 +/- 0.2 cm2. The mean aortic flow velocity integral was 21.8 +/- 0.8 cm. This information was used to calculate aortic stroke volume and cardiac output. Thermodilution- and Doppler-derived estimations for maternal stroke volume (r = 0.86) and cardiac output (r = 0.94) were significantly correlated when aortic diameter measurements based on a leading vessel edge method were used. Our findings verify the accuracy of an important noninvasive technique for quantitating maternal stroke volume and cardiac output by pulsed Doppler echocardiography. This methodology should provide an alternative approach to invasive monitoring in the study of normal and abnormal maternal circulatory hemodynamics.

Aorta↗
PubMed1988

Hemodynamic profile of severe pregnancy-induced hypertension.

Cases of severe pregnancy-induced hypertension or eclampsia were studied in forty-five women by catheterization of the right side of the heart to define the presenting hemodynamic profile associated with this disorder. These women could not be easily categorized into one specific hemodynamic pattern. Most patients had high-normal to elevated systemic vascular resistance indices (mean 2726 +/- 120 dynes.sec.cm-5.m2). The mean cardiac index was 4.14 +/- 0.13 L.min-1.m2. The severity of hypertension was largely attributable to a disproportionate rise in the systolic component (mean 193 +/- 3 mm Hg) compared with diastolic blood pressure (mean 110 +/- 3 mm Hg). Women with eclampsia had significantly lower arterial blood pressure and systemic vascular resistance indices when compared with those of the rest of the study group. Analysis of Starling curves indicated that all patients had normal or hyperdynamic left ventricular function. A modest correlation was observed between central venous pressure and pulmonary capillary wedge pressure (r = 0.59). This disparity most likely results from the maintenance of normal to high cardiac output in the presence of an increased left ventricular afterload. The majority of patients with severe pregnancy-induced hypertension do have normal to high cardiac indices and pulmonary capillary wedge pressures accompanied by normal or hyperdynamic left ventricular function. This is true despite the presence of severe hypertension.

Adult↗
PubMed1988

Effects of low-dose dopamine therapy in the oliguric patient with preeclampsia.

Central hemodynamic and renal responses to low-dose dopamine (1 to 5 micrograms/kg/min) infusion were studied in six oliguric (less than 0.5 ml/kg/hr) patients with severe preeclampsia. Hemodynamic parameters were measured and renal function tests were done before and during therapy. There was a significant rise in urine output from a mean (+/- SD) of 21 +/- 10 to 43 +/- 23 ml/hr, accompanied by a rise in cardiac output from 6.8 +/- 1.8 to 8.0 +/- 2.3 L/min (p less than or equal to 0.05). There were no significant changes in blood pressure, central venous pressure, or pulmonary capillary wedge pressure. The fractional excretion of sodium, negative free water clearance, and osmolar clearance tended to rise during dopamine therapy. No adverse maternal or fetal effects occurred. We conclude that low-dose dopamine produces a significant increase in urine production with resolution of oliguria in severe preeclampsia.

Adult↗
PubMed1988

Septic shock during pregnancy.

A multiinstitutional review of 10 pregnancies complicated by septic shock was undertaken to identify the clinical characteristics and hemodynamic alterations associated with this condition. Prolonged rupture of membranes with the subsequent development of chorioamnionitis or postpartum endometritis were risk factors that commonly preceded the diagnosis of septic shock. The majority of septic shock cases occurred during the puerperium. There were two maternal deaths in this selected series. Associated complications included pulmonary edema, adult respiratory distress syndrome, disseminated intravascular coagulation, pulmonary emboli, and cardiac arrest. The primary hemodynamic derangements were reduced systemic vascular resistance with depressed myocardial function. The mean initial systemic vascular resistance index in eight surviving women was 885 +/- 253 dyne.sec/cm5.m2. Despite an overall presenting cardiac index of 4.20 +/- 2.01 L/min/m2, five patients (50%) had evidence of myocardial depression based on analysis of their left ventricular function curves. Mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index all showed significant improvement after therapy. A hemodynamic algorithm based on volume therapy, inotropic agents, and peripheral vasoconstrictors is offered. This therapeutic approach is designed to optimize cardiac performance and maintenance of organ perfusion in the critically ill patient with septic hypotension during pregnancy.

Blood Pressure↗
PubMed1988

Effect of chronic atropine administration on the rat urinary bladder.

Micturition is accomplished via a coordinated contraction of the urinary bladder body mediated primarily by muscarinic receptor stimulation. Theoretically, bladder function may be modified by pharmacologically altering either the muscarinic receptor density and/or the magnitude of the response to receptor activation. In the central nervous system, autonomic receptor density can be modified by chronic administration of specific receptor agonists and antagonists. The chronic administration of receptor agonists induces a decrease in the specific receptor density whereas the chronic administration of antagonists induces an increase in the specific receptor density. Although these induced alterations in receptor density occur in the CNS, there have been few studies on peripheral tissue. For the current study, we have administered L-atropine chronically to rats (five mg./kg./day) using implanted osmotic pumps. Using direct radioligand binding techniques, the muscarinic receptor density of the rat brain (cortex) and urinary bladder were determined following six hours, 12 hours, one, two, four, seven, 11 and 14 days of atropine administration. In addition, we have also determined the effect of atropine administration on bladder weight and the response of isolated strips of the bladder to bethanechol, a specific muscarinic agonist. For both the brain and the bladder, the receptor density increased progressively and reached a maximum by seven days. At 14 days of atropine administration, the density of muscarinic receptors in rat brain increased significantly (p less than .05) from 2956 +/-74 fmoles/mg. protein to 3800 +/-170 fmoles/mg. protein. The muscarinic receptor density of the rat urinary bladder increased significantly from 115 +/-10 fmole/mg. protein to 165 +/-14 fmole/mg. protein. Although there was a 42% increase in bladder mass, the contractile response of isolated strips to bethanechol did not change significantly. This study demonstrates that the urinary bladder can respond to the chronic administration of atropine with a significant increase in the density of muscarinic receptors. The magnitude of the increase observed was slightly greater than the magnitude observed for muscarinic receptors isolated from the brain cortex.

Animals↗
PubMed1988

A comparison of DNA and immunoblot fingerprinting of the SII biotype of coagulase negative staphylococci.

Thirty-eight isolates of the SII biotype of coagulase negative staphylococci were examined by phase typing, antibiograms, DNA and immunoblot fingerprinting. Multiple isolates were available from 5 patients with clinically proven infections and from 12 further patients who were epidemiologically distinct. Only 3 of the isolates were phage typable and antibiograms produced only 9 types. All isolates were typable by both DNA and immunoblot fingerprinting and reproducibility was excellent provided the conditions were standardized. Discrimination was better with immunoblot fingerprinting (17 types) than DNA fingerprinting (11 types). Both techniques were successful in assessing the significance of multiple isolates from a single patient.

Bacterial Typing Techniques↗
PubMed1988

Formulation of vaccine adjuvant muramyldipeptides (MDP). 2. The thermal reactivity and pH of maximum stability of MDP compounds in aqueous solution.

The degradation of muramyldipeptides (MDPs) in aqueous solution obeys the rate law kobs = kH+aH+ + ko + kHO-aHO- and the Arrhenius equation. For example, the rate constants for degradation of N-acetylmuramyl-L-threonyl-D-isoglutamine, 3, at 25 degrees C are kH+ = 2.3 X 10(-6) M-1 sec-1, ko = 8.2 X 10(-10) sec-1, and kHO- = 0.19 M-1 sec-1. The degradation rates are dependent on the side-chain substituents; it is predicted that sterically hindered MDP compounds will show an extended shelf life in aqueous solution. Product studies in the weakly acid pH region (where the pH of maximum stability occurs) show that MDP compounds degrade largely by hydrolysis of the dipeptide side chain. These data show that MDP 3 exhibits a shelf life (t90) of greater than 2 years in aqueous solutions of pH 4-4.5, the pH of maximum stability.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1988

Ascorbic acid status: biochemical and clinical considerations.

Ascorbic acid (AA) plus dehydroascorbic acid (DHAA) was stable in whole blood in unopened vacutainer tubes. Oxidation of DHAA in plasma was irreversible and rapid at 25 degrees C but not at 4 degrees C. The half-life of AA + DHAA in total parenteral nutrition solutions was greater than 24 h. Conditions are described for dithiothreitol reduction of DHAA followed by assay of total AA, with DHAA being determined by difference. DHAA accounted for less than 5% of the total plasma AA + DHAA in both healthy and diabetic subjects. Infection and postpartum-induced stresses resulted in no significant change in the AA content of polymorphonuclear leukocytes (PMN) per unit of blood but AA content per cell was decreased. When glucose concentration was increased, the Km for AA uptake by PMNs doubled. These chemical and physiological factors combined with the rapid movement of the vitamin between plasma and cells suggest that a reliable indicator of AA status remains to be identified.

Ascorbic Acid↗
PubMed1988

Untargeted viral mutagenesis is not found in X-irradiated monkey cells.

The existence of untargeted viral mutagenesis in X-irradiated cells was investigated in a mammalian virus/cell system, where a low level of such viral mutagenesis can be demonstrated in UV-irradiated cells. In the positive control experiment UV-elicited mutagenesis was shown with cell exposures of 5, 10 and 15 J/m2 and a delay of 24 h between cell irradiation and infection with unirradiated herpes simplex virus. Although X-ray doses of 1, 3 and 10 Gy elicit enhanced reactivation of UV-irradiated virus, no untargeted mutagenesis for any X-ray dose at post-irradiation infection times of 0, 24 or 72 h was observed in this study. Thus untargeted mutagenesis of herpes simplex virus was not demonstrated in X-irradiated monkey cells, under conditions where X-ray-enhanced reactivation occurs and where untargeted mutagenesis in UV-irradiated cells occurs.

Animals↗
PubMed1988

Field testing of the movement assessment of infants.

The purpose of this study was to compare the test results of normal 4-month-old infants on the Movement Assessment of Infants with the published Movement Assessment of Infants a priori profile. We tested 50 healthy 4-month-old infants (24 white, 20 black, 6 other races) on 65 Movement Assessment of Infants items, encompassing the categories of muscle tone, primitive reflexes, automatic reactions, and volitional movements. The total-risk score was a sum of categorical risk scores. A between-group analysis of variance showed that the total-risk scores did not differ significantly by sex or race. Thirty percent of the infants we tested had total-risk scores greater than 7, which differed significantly from the 15% in the original Movement Assessment of Infants data. On 18 of the 65 Movement Assessment of Infants items, more than 15% of our study sample had risk scores that differed from Movement Assessment of Infants profile normative scores. The results of our study suggest that the current Movement Assessment of Infants profile may not accurately reflect the normal motor behavior of a 4-month-old infant. Suggestions for revising the Movement Assessment of Infants are made that could improve the reliability and validity of the test.

Analysis of Variance↗
PubMed1988

Fingerprinting methicillin-resistant Staphylococcus aureus by the immunoblot technique.

A series of 133 isolates of methicillin-resistant Staphylococcus aureus was fingerprinted by the immunoblot technique. Extracts were prepared by lysostaphin degradation of overnight cultures and peptides were separated by SDS polyacrylamide gel electrophoresis. The peptides were transblotted on to nitrocellulose membranes and probed with (1) a hyperimmune rabbit serum raised against a methicillin-resistant S. aureus isolate, (2) a hyperimmune rabbit serum raised against an isolate of S. epidermidis, and (3) serum from a patient who had recovered from an infection with a methicillin-resistant S. aureus. This typing method confirmed the existence of an epidemic strain that accounted for 102 of the isolates. The remaining 31 isolates were grouped into a further seven types which correlated with the results of phage typing and antibiograms.

Animals↗
PubMed1988

Immunoblot fingerprinting of Campylobacter pylori.

One hundred and fifty isolates of Campylobacter pylori were divided into nine groups by immunoblot fingerprinting. All isolates were typable and reproducibility between immunoblots was good provided both antigen and antibody preparation were standardised. Discrimination was a problem as Groups 1 and 2 accounted for 66% of isolates. Recurrence after bismuth treatment was due to indistinguishable strains in five patients and different strains in three patients.

Antigens, Bacterial↗
PubMed1988

[Experimental and clinical studies on the value of MRI in the diagnosis of lumbar disc lesions].

This dissertation reports basic and clinical research performed on the value of magnetic resonance imaging (MRI) in the diagnosis of lumbar disc lesions. With the T2 weighted spin echo image (T2-W-SE), the center portion of normal discs showed high signal intensity, with gradual drop-off signal intensity toward the edges. Experiments using gelatine indicated that this change in signal intensity resulted from the change in water content of the disc. In contrast to discograms, the use of MRI allowed disc degeneration to be classified into the three levels of "normal", "mild degeneration" and "moderate or severe degeneration". MRI allowed excellent depiction of disc herniation, even where a myelogram showed a complete block, and it also readily distinguished recurrent disc herniation and post-operative scarring.

Adolescent↗
PubMed1988

Prompt resolution of hyperthyroidism and hyperemesis gravidarum after delivery.

Severe hyperemesis gravidarum has often been associated with elevated thyroid function. However, it has not been determined whether establishing euthyroidism will result in prompt resolution of nausea and vomiting. We report here a gravida with severe intractable hyperemesis gravidarum requiring four months of parenteral hyperalimentation. This patient consistently demonstrated biochemical evidence of hyperthyroidism with no symptoms and signs other than nausea and vomiting. Although no parenteral form of antithyroid medication is commercially available, methimazole suppositories were developed and administered until thyroid function tests normalized. Despite euthyroidism, nausea and vomiting continued unabated. After delivery, both the elevated thyroid function and the nausea and vomiting resolved within three days.

Female↗