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Biomedical subjects

L Kaplan

Publications and source records attributed to L Kaplan.

At least 109 records · Page 6Linked to original sources
PubMed1987

Adrenergic receptors in inner and outer layers of human myometrium near term: characterization of beta-adrenergic receptor sites by [125I]-iodocyanopindolol binding.

The beta-adrenergic receptors present in inner and outer layers of human myometrium near term were characterized using the radioiodinated antagonist iodocyanopindolol (ICYP). In both layers ICYP binding is saturable, rapidly reversible, stereoselective, and appears to occur in a single class of sites with a KD of 30 pmol/l. Adrenergic agonists compete for ICYP binding sites with an order of potency consistent with beta 2-adrenergic potencies: isoproterenol greater than epinephrine much greater than norepinephrine. Studies in which CGP 20712 A, a beta 1-adrenergic antagonist, competes for ICYP binding sites in human myometrium reveal that at least 65% of the beta-receptors present are beta 2-subtype, whatever the layer considered. At the 35th week of pregnancy, the density of beta-adrenergic receptors in the inner layer (15.2 fmol/mg of protein) is about 50% higher than in the outer layer. At term, the densities of beta-adrenergic receptors are reduced and exhibit the same values for both layers (5 fmol/mg of protein). These results indicate that the beta-adrenergic receptors in the two layers diminish during pregnancy and reach, at term, an equal and low level of density.

Binding Sites↗
PubMed1987

Osteolytic osteogenic sarcoma of ilium in 46-month-old boy.

A 46-month-old boy with a four-day history of pain and swelling over the right posterior ilium was thought to have acute osteomyelitis on the basis of a normal pelvic x-ray, markedly increased scintigraphic activity in the right ilium, and a mildly elevated sedimentation rate. At surgery, no signs of osteomyelitis were found, and biopsy revealed osteolytic osteogenic sarcoma. This is the youngest child with osteogenic sarcoma of the pelvic reported in the literature.

Bone Neoplasms↗
PubMed1986

Bilateral nephrectomy for Wilms tumor.

Bilateral nephrectomy was performed in 4 patients with bilateral Wilms tumor. The current philosophy regarding the need to preserve maximum renal parenchyma is discussed. New guidelines suggested by the National Wilms Tumor Study group discourage unilateral nephrectomy and partial nephrectomy at initial exploration for bilateral Wilms tumor. Alternatively, it is recommended that continued treatment with chemotherapy and/or radiation therapy followed by second and third-look operations to maximize preservation of renal parenchyma be done with bilateral nephrectomy as a last resort option.

Child, Preschool↗
PubMed1986

Glycemic control and spontaneous abortion in insulin-dependent diabetic women.

Insulin-dependent diabetic women without adequate glucose control have a higher spontaneous abortion rate when compared with the general population. The present study examined whether the increased rate of spontaneous abortions in insulin-dependent diabetic women was associated with poor glycemic control in the early postconceptional period or close to the abortive event itself. Measurements of glycohemoglobin A1 at eight to nine weeks' gestation provide retrospective indexes of glucose control during the early postconceptional period, whereas measurement of glycosylated serum albumin and serum protein at the same time reflects short-term glycemic control before the abortive event. This study evaluated 84 consecutive pregnancies occurring in 68 insulin-dependent diabetic women; 66 pregnancies progressed beyond 20 weeks with no malformation or death, and 18 pregnancies terminated in spontaneous abortions before 20 weeks' gestation. The mean glycohemoglobin A1 concentrations of women experiencing spontaneous abortions were significantly greater than that of women who did not abort (P less than .05). In contrast, maternal glycosylated proteins and glycosylated albumin concentrations did not differ between groups. The authors suggest that poor control of diabetes in the early conceptional period, rather than that just before abortion, increases the risk of spontaneous abortion.

Abortion, Incomplete↗
PubMed1986

Avermectin B2 O-methyltransferase activity in "Streptomyces avermitilis" mutants that produce increased amounts of the avermectins.

The level of activity of avermectin B O-methyltransferase, the enzyme which catalyzes the conversion of avermectin B components to avermectin A components, was analyzed in a series of "Streptomyces avermitilis" mutants selected for increased production of the avermectins. In all of the mutants, increased avermectin production was accompanied by increased avermectin B O-methyltransferase activity. Both the average specific activity and the maximum observed specific activity of avermectin B O-methyltransferase increased in direct proportion to avermectin production. The level of avermectin B O-methyltransferase alone did not determine the extent of conversion of avermectin B components to avermectin A components, since a constant ratio of B components to A components was maintained throughout the fermentation even though avermectin B O-methyltransferase specific activity varied three- to fivefold. These results indicate that avermectin B O-methyltransferase is not rate limiting. The correlation between avermectin B O-methyltransferase specific activity and avermectin production is compatible with the hypothesis that genes coding for successive steps in the same secondary metabolite biosynthetic pathway are coordinately regulated.

Bacterial Proteins↗
PubMed1986

Aortic pseudo-aneurysm with Aspergillus aortitis. An unusual complication of coronary bypass surgery.

This is the first report of fatal postoperative Aspergillus infection in an aortic pseudoaneurysm associated with a jet lesion produced by a deformed, but hemodynamically normal aortic valve. Widespread arterial embolization was the principal feature and resulted in death on the 12th hospital day due to massive thromboembolism to the brain three months after successful coronary bypass surgery. Possible sources of such infections and the potential effect of the jet lesion are discussed.

Aged↗
PubMed1986

Safety of helicopter transport and out-of-hospital intravenous fibrinolytic therapy in patients with evolving myocardial infarction.

Of 150 consecutive patients with acute myocardial infarction transported by helicopter for acute intervention, 55 had intravenous thrombolytic therapy (tissue plasminogen activator in 12, streptokinase in 43) initiated prior to transfer. Patients were transported 55 +/- 10 ground miles in 17 +/- 6 minutes and no patient died or experienced bleeding or hemodynamic instability during transfer. Patients receiving thrombolytic therapy had a higher incidence of arrhythmias during transit compared to the untreated group, ventricular tachycardia in six and third-degree atrioventricular block in one compared to ventricular tachycardia in one patient, respectively (p = 0.005). However, these arrhythmias were transient and did not require cardioversion, temporary pacing, or further antiarrhythmic medical treatment. Chest pain was relieved or decreased more frequently in the patients receiving thrombolytic therapy vs. those untreated; 21 of 55 vs. 21 of 95 respectively (p = 0.04). Immediate coronary angiography confirmed a higher incidence and more complete infarct vessel patency (34/55 vs. 30/95) in the patients receiving tissue plasminogen activator or streptokinase (p less than 0.001). Thus, helicopter transfer of patients with evolving myocardial infarction is safe, and early initiation of thrombolytic therapy is associated with increased infarct vessel patency and benign reperfusion arrhythmias.

Aircraft↗
PubMed1986

Treatment of Kaposi's sarcoma in acquired immunodeficiency syndrome with an alternating vincristine-vinblastine regimen.

Twenty-four patients with acquired immunodeficiency syndrome and Kaposi's sarcoma (KS) were treated with a regimen alternating vincristine with vinblastine on a weekly basis. Objective responses to this regimen were observed in nine patients (45%), and seven (35%) had stabilization of progressive KS. Few toxic effects were observed. Alternating vincristine-vinblastine therapy is well-tolerated and effective palliative treatment for KS in acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Large-scale purification of human tissue-type plasminogen activator using monoclonal antibodies.

Tissue plasminogen activator produced by a human melanoma cell line (Bowes), was purified from large volumes of supernatant fluid using immunosorbent chromatography on monoclonal antibodies, followed by chromatography on lysine-Sepharose 4B and gel filtration on Sephadex G-150. Immunosorbents based on monoclonal antibodies were shown to be preferable to those based on polyclonal antibodies for several reasons: efficient binding and desorption, high yield along with a high degree of purification. The overall recovery was about 50%. A homogeneous sample of single-chain tissue plasminogen activator with a molecular weight of approx. 65 000 was obtained as judged by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Amino acid sequence analysis revealed two N-terminals in equal yields, corresponding to the long and short tissue plasminogen activator structures previously reported by others. The pure preparations of tissue plasminogen activator showed specific activities of about 200 000 IU/mg protein.

Amino Acid Sequence↗
PubMed1985

Demethylavermectins. Biosynthesis, isolation and characterization.

Streptomyces avermitilis normally produces eight avermectins. Avermectin A components contain three methoxyl groups; two on the oleandrose disaccharide and one on the aglycone moiety at C5. Avermectin B components contain methoxyl groups only on the oleandrose disaccharide. Sinefungin inhibits methylation at all three sites. Addition of sinefungin to S. avermitilis Agly-1, a mutant which produces virtually only avermectin aglycone A components, alters the fermentation and causes an accumulation of avermectin aglycone B components. Addition of sinefungin to S. avermitilis 08, a high producing strain, results in accumulation of 8 new avermectins which lack methoxyl groups on the oleandrose moieties as well as the aglycone. These new avermectins were isolated and shown to possess anthelmintic and insecticidal activity.

Adenosine↗
PubMed1984

Rapid and early determination of sex using trophoblast biopsy specimens and Y chromosome specific DNA probes.

The feasibility of determining sex by analysing deoxyribonucleic acid (DNA) with two probes specific for Y chromosomes was shown using DNA obtained from samples of blood from 30 non-related males and females of different ethnic origin. The DNA was spotted on nitrocellulose filters and hybridised with both a repetitive (P1) and a unique (49f) sequence specific for the human Y chromosome. A strong positive signal with both probes indicated the presence of male DNA. The sex of 12 fetuses was then similarly determined by molecular characterisation of DNA from trophoblast biopsy specimens. Chorionic samples were obtained in seven cases before termination of pregnancy in the first trimester and the aborted embryos subjected to karyotyping and sex chromatin analysis. In the five other cases samples were obtained from placentas obtained during caesarean section. Results of hybridisation were compared with those from cytogenic studies and actual sex at birth. The sex of all 12 fetuses was determined correctly by hybridisation.

Chorionic Villi↗
PubMed1984

Differences between uterine and melanoma forms of tissue plasminogen activator.

Tissue plasminogen activator purified from human uterine tissue exhibits differences in N-terminal starting positions in relation to the melanoma cell plasminogen activator usually studied. A new starting position is compatible with an additional N-terminal processing apart from those already known. Like the melanoma activator, the uterine activator was found to yield protein chains starting at either of two positions. One of these was identical between uterine and melanoma activators, whereas the other was unique in each case. The most abundant starting position for the uterine preparation was at a valine residue, apparently from cleavage of a Gln-Val bond, and corresponding to Val-7 of the longest form of the melanoma activator chain.

Amino Acid Sequence↗
PubMed1984

Postmortem diagnosis of myocardial disease by enzyme analysis of pericardial fluid.

The authors measured the activities of CK, LDH, and their isoenzymes in pericardial fluid to determine their usefulness in evaluating acute myocardial injury. Their prospective study reveals that these enzymes significantly are elevated in cardiac deaths in contrast to fatalities from noncardiac causes. Also, a group of healthy individuals who were victims of violent deaths and died from extracardiac injuries had enzyme elevations greater than those found in acute cardiac deaths, suggesting catecholamine-mediated myocardial injury (stress cardiomyopathy) as part of the physiologic response to trauma. Measurements of cardiac enzymes in pericardial fluid may prove useful in establishing the postmortem diagnosis of acute myocardial injury in instances when such injury is suspected but cannot be established by ordinary histologic methods. Studies such as this may help in defining the participation of myocardial injury as one of the lethal mechanisms in various causes of death.

Autopsy↗
PubMed1984

Evaluation of possible first trimester prenatal diagnosis in lysosomal diseases by trophoblast biopsy.

The detection of enzymatic deficiency in cultured amniotic cells from second trimester pregnancies is presently used for prenatal diagnosis of lysosomal diseases. The possibility of obtaining and processing trophoblast tissue at 8-10 weeks of gestation would permit first trimester prenatal diagnosis. Using trophoblast tissue samples from normal fetuses before voluntary abortion and from placenta after therapeutic abortions of fetuses affected by several lysosomal diseases, we conclude that early diagnosis of lysosomal disorders would be possible.

Biopsy↗