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Biomedical subjects

M C Lee

Publications and source records attributed to M C Lee.

At least 307 records · Page 17Linked to original sources
PubMed1984

Lectin histochemistry of human placenta.

The human placenta was studied histochemically using 23 fluorescein-isothiocyanate-labeled lectins. Distinct patterns of staining, as well as some differences between first-trimester and term placenta, were discerned. Eleven lectins (HPA, VVA, BPA, HAA, SBA, PNA, GSA-I, MPA, RCA-I, RCA-II, and UEA-I) did not react with the trophoblast. Two lectins (LCA and PEA) reacted with the trophoblast of first-trimester placenta but not with the trophoblast of third-trimester placenta. The remaining ten lectins (ConA, Suc.ConA, WGA, GSA-II, LAA, STA, DBA, LBA, PHA-E, and PHA-L) reacted with the trophoblast of both first- and third-trimester placenta, and two of these lectins (ConA and Suc.ConA) reacted preferentially with the syncytiotrophoblast. Five lectins (LAA, STA, DBA, GSA-II, and LBA) reacted with nuclei of the cytotrophoblast. The nuclei of some stromal and syncytiotrophoblastic cells were also reactive. Eighteen lectins reacted with the trophoblastic basement membrane, and all reacted with Hofbauer cells and the stroma of the villi. Lectin binding was influenced by the mode of fixation and tissue processing. These data show that some lectins can be used to identify components of the placental villi (e.g., basement, membrane) to characterize differences between the first- and third-trimester trophoblast, and to distinguish the cytotrophoblast from the syncytiotrophoblast.

Basement Membrane↗
PubMed1984

Anatomic distribution of lectin-binding sites in mouse testis and epididymis.

Testis and epididymis of sexually mature mice were studied histochemically using 25 fluorescein-isothiocyanate-labeled lectins. Several lectin-specific binding patterns were recognized. Thus, HAA, HPA, GSA-I, and UEA-II reacted only with spermatozoa. PNA, GSA-II, SBA, VVA, BPA, RCA-I, and RCA-II reacted with spermatozoa and spermatocytes. WGA, PEA, LCA, and MPA reacted with spermatogonia, spermatocytes, and spermatozoa in increasing order of intensity. ConA, Suc. ConA, LAA, STA, LTA, LPA, PHA-E, PHA-L, UEA-I, and LBA reacted with all spermatogenic cells with equal intensity. In the epididymis, 12 lectins reacted uniformly with the epithelial cells lining all segments of this organ. One lectin (VVA) did not react with epididymal lining cells. The remaining 12 lectins reacted in a specific manner with portions of the head, body, or tail, thus selectively outlining different portions of the epididymis. RCA-I and RCA-II selectively accentuated the so-called halo cells of the epididymis. These findings provide a detailed map of lectin-binding sites in the mouse testis and epididymis and show that certain lectins can be used as specific markers for spermatogenic cells and segments of the epididymis.

Binding Sites↗
PubMed1983

Pregnancy-related changes in the mouse oviduct and uterus revealed by differential binding of fluoresceinated lectins.

The binding of 20 fluorescein isothiocyanate (FITC)-labeled lectins to various portions of the pregnant and non-pregnant murine oviduct and uterus was studied by fluorescence microscopy. Five lectins (from Ricinus communis (RCA-I), Maclura pomifera (MPA), Triticum vulgare (wheat germ-WGA), Bauhinia purpurea (BPA), and Ulex europeus (UEA-I] reacted differentially with the epithelium of pregnant as compared with the non-pregnant uterus. The binding of RCA-I, MPA and WGA delineated pregnancy-related changes in the distal oviduct and colliculus tubaris. WGA recognized also pregnancy related changes in the proximal oviduct. The reactivity of the remaining 15 lectins did not distinguish the pregnant and non-pregnant oviduct and uterus, although some of them served to identify specific components of the mouse genital tract. Thus, Soybean lectin (SBA) reacted almost exclusively with the colliculus tubaris. UEA-I alone reacted exclusively with the epithelium of the non-pregnant uterus. RCA-II reacted preferentially with the epithelium of the oviduct and uterus as compared with its weak reactivity with the stroma. Two lectins (from Pisum sativum and Lens culinaris) reacted selectively with stromal cells of the uterus and oviduct. Present data indicate that the differential binding properties of these FITC-labeled lectins can be exploited to identify certain components of the mouse oviduct and uterus and to indicate changes in the cell surface and/or cytoplasm in these structures during pregnancy.

Animals↗
PubMed1983

Analysis of the anti-alpha 1 leads to 3 dextran response with monoclonal anti-idiotype antibodies.

The antibody response to alpha 1 leads to 3 dextran (DEX) in BALB/c mice consists of a family of closely related yet highly heterogeneous molecules. Although these antibodies have been previously characterized both idiotypically and structurally, detailed analysis of responding clones has not been possible using conventional anti-idiotype antibodies. Monoclonal syngeneic and allogeneic anti-idiotype antibodies (MAIDs) specific for anti-DEX antibodies were used in this study to dissect the serum antibody response to DEX in BALB/c mice. The constructed MAIDs showed considerable heterogeneity by isoelectric focusing and by their binding characteristics to a series of DEX specific myeloma and hybridoma proteins. The predominant heavy chain isotype of these MAIDs was gamma 1. These antibodies were used to identify individual idiotypic structures (IdI) on J558, or M104E as well as cross-reactive determinants common to both (IdX). Although both IdX and IdI MAIDs were obtained, IdI specific antibodies were obtained more frequently. BALB/c mice immunized with DEX produced antibodies expressing both IdI but in highly variable amounts. A large percentage of, but not all DEX specific antibody, could be accounted for by IdX bearing antibodies. Suppression of adult and neonatal mice by IdI specific MAIDs was effective with precise elimination of only those clones expressing IdI determinants leaving the total lambda bearing anti-DEX response intact. Suppression of adults and neonates by an IdX specific MAID resulted in a temporary and partial suppression of the total lambda bearing anti-DEX response along with total suppression of the IdX portion of the response. Unlike other systems these monoclonal antibodies produce only suppression, and under a variety of conditions enhancement of anti-DEX responses has not been observed.

Animals↗
PubMed1981

Is angiotensin essential in drinking induced by water deprivation and caval ligation?

The role of the renin-angiotensin system in drinking induced by water deprivation and caval ligation was assessed by infusion of saralasin into the lateral ventricles of rats. This technique was first validated by demonstrating its capability to specifically antagonize drinking to both systemic and central angiotensin II. However, neither the latency to drink nor the amount of water consumed following 24- or 30-h water deprivation was affected by saralasin. Furthermore, saralasin had no significant effect on the recovery of blood pressure or on the water intake following ligation of the abdominal vena cava. These observations suggest that the renin-angiotensin system alone does not play an essential role in the control of drinking following water deprivation or caval ligation in rats.

Angiotensin II↗
PubMed1980

Altered cerebral inhibition of respiratory and cardiac responses to hypercapnia in acute stroke.

Ventilatory and heart-rate responses to hypercapnia were evaluated by a CO2 rebreathing technique in 56 patients with acute ischemic stroke and 14 normal controls. Both ventilatory and heart-rate responses were increased in patients with hemispheral lesions, but not in patients with brainstem lesions. In patients with hemispheral infarct, there was a decrease in CO2 sensitivity 1 to 3 weeks later. Acute hemisphere lesions may result in a transient decrease of cerebral inhibition of brainstem-mediated autonomic responses to a chemical stimulus.

Adolescent↗
PubMed1979

Superficial temporal to middle cerebral artery anastomosis. Clinical outcome in patients with ischemia of infarction in internal carotid artery distribution.

The clinical outcome of our first 40 patients (six with transient ischemic attacks, 22 with mild ischemic infarctions, and 12 with moderate ischemic infarctions) treated with a superficial temporal artery-middle cerebral artery anastomosis was analyzed. All cerebral ischemias or infarctions occurred in the internal carotid artery distribution. An independent neurologist observer recorded the patients preoperative and postoperative medical and neurological histories and objective neurological findings. There was no operative mortality. During the period of observation (up to 36 months), four patients died of probable myocardial infarction. No patient suffered from recurrent cerebral infarction. Three patients experienced a single ischemic event postoperatively. Neurological deficits were either unchanged (21 patients) or improved (19 patients). Postoperative angiograms showed patency in 97% of the anastomoses.

Adult↗
PubMed1979

Hypercapnic alteration of visual evoked responses in acute cerebral infarction.

To determine the effect of inhaled carbon dioxide on acute ischemic cerebral injury, we have compared occipital visual evoked responses (VER) at baseline and during hypercapnia in 20 patients with acute unilateral cerebral infarction (ten with and ten without homonymous hemianopsia) and in ten normal controls. Visual evoked responses were judged on the basis of interhemispheral symmetry. In eight of ten controls and six of 20 patients, baseline VERs were symmetrical and remained unchanged during hypercapnia. In 14 patients with asymmetrical baseline VERs, hypercapnia caused improvement of symmetry in five, worsening in three, and no change in six. Hypercapnic vasodilation may be either beneficial or deleterious to cerebral function in patients with acute cerebral infarction.

Acute Disease↗
PubMed1979

Superficial temporal-middle cerebral artery bypass. A detailed analysis of multiple pre- and postoperative angiograms in 40 consecutive patients.

Pre- and postoperative angiograms on 40 patients undergoing superficial temporal-middle cerebral artery (STA-MCA) bypass surgery have been examined in detail. Multiple postoperative angiograms have been obtained to evaluate the change in both the bypass circuit and the intracranial circulation over time. A reproducible system for evaluating the degree of intracranial vascular filling via the bypass is introduced. The study shows that the STA and its anastomotic branch increase in size over time, measured in months, in the majority of patients. This is paralleled by a progressive increase in the degree of intracranial vascular filling. These changes are proportional to the severity of the vascular disease before surgery. The pattern of preoperative collateral circulation may change over time following the addition of the bypass circuit. The progressive change over time suggests that a static analysis at one time may belie the true effect of the surgery. The change of collateral circulation with augmentation of blood supply to areas of the brain other than those affected by the recent ischemic event, means that a total cerebral evaluation including neuropsychological testing may be necessary for adequate evaluation of the effect of the bypass surgery.

Brain Ischemia↗