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Biomedical subjects

M Strauss

Publications and source records attributed to M Strauss.

At least 199 records · Page 11Linked to original sources
PubMed1988

Chemical synthesis of a gene for human stefin A and its expression in E. coli.

A DNA containing the coding sequence for the human cysteine proteinase inhibitor stefin A was obtained by enzymic ligation of chemically synthesized deoxyoligonucleotides, using the Khorana ligation method. The 306-bp synthetic gene carries signals for the initiation and termination of its translation. The gene was expressed in E. coli using a cytoplasmic expression vector and stefin A was secreted under the control of the E. coli alkaline phosphatase signal sequence, respectively. The secreted hybrid protein was shown to exhibit biological properties similar to the native protein isolated from human plasma.

Amino Acid Sequence↗
PubMed1988

Chemical synthesis of a gene for human cystatin C and its expression in E. coli.

A DNA containing the coding sequence for the human cysteine proteinase inhibitor protein cystatin C has been obtained by enzymatic ligation of chemically synthesized deoxyoligonucleotides, using the Khorana ligation method. The 375 bp synthetic gene carries signals for the translation initiation and termination and was expressed in E. coli as a beta-galactosidase fusion protein as well as a secreted protein under the control of the E. coli alkaline phosphatase signal sequence. The secreted hybrid protein was shown to have similar biological properties as the authentic protein isolated from human plasma.

Amino Acid Sequence↗
PubMed1988

Digoxin-cyclosporine interaction: severe digitalis toxicity after cyclosporine treatment.

Digoxin toxicity developed in two patients awaiting cardiac transplantation upon the initiation of cyclosporine. Toxicity was associated with elevated digoxin concentrations (10.6 and 5.7 nmoles/L), gastrointestinal symptoms, and arrhythmias classic for digoxin toxicity (bidirectional ventricular tachycardia and AV nodal block with accelerated junctional rhythm respectively). A previously unreported drug interaction between cyclosporine and digoxin was suspected and digoxin pharmacokinetics were studied in two additional patients both before and after cyclosporine therapy prior to cardiac transplantation. The study confirmed a significant interaction between cyclosporine and digoxin; the apparent volume of distribution of digoxin decreased by 71% and its plasma clearance decreased by 53%. Until further information regarding the cyclosporine-digoxin interaction is available, this combination should be used with great caution.

Coronary Disease↗
PubMed1987

Mesenchymal tissue of the interventricular septum. Structural and ultrastructural study.

Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28-29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process. The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.

Animals↗
PubMed1987

Origin of mesenchymal tissue in the septum primum: a structural and ultrastructural study.

A structural, ultrastructural and histochemical study in chick embryos indicates that the septum primum mesenchymal tissue originate between 3 and 5 days of development and that their origin may be related to an activation of endocardial cells that cover the septum primum. By day 3, endocardial cells display migratory appendages, cell hypertrophy and an increase in secretory and mitotic activity. In later stages (day 4) hypertrophic endocardial cells undergoing division seem to delaminate and translocate toward the subendocardial space to give rise to free mesenchymal-type cells. These results suggest that the endocardium makes up the bulk of the septum primum mesenchymal tissue as has been demonstrated during mesenchymal tissue formation in the atrioventricular canal and outflow tract. Before and during mesenchymal tissue formation an accumulation of extracellular matrix components like proteoglycans can be visualized using tannic acid. These extracellular components might be related to the promotion of cellular events described during endocardial activation. The fusion of the septum primum with the atrioventricular (AV) endocardial cushions which would obliterate the foramen primum, occurs between mesenchymal tissues. Therefore, any alteration in the normal development of these mesenchymal tissues could be related to pathological cases of persistent atrial communications. Light microscopy preliminary observations of embryonic mouse heart indicate that septum primum mesenchymal tissue formation occurs similarly between mouse and chick embryos.

Animals↗
PubMed1987

Influence of the mesenchymal microenvironment on myocardial and endocardial cell behaviour in experimental interaction with chick limb mesenchyme.

In an attempt to clarify the possible influence of the mesenchymal microenvironment in the differentiation of myocardial and endocardial cells, an "in vivo" transplantation experiment was performed in which the ventricular region of the heart (chick or quail) was placed in close association to the mesenchyme of the anterior chick limb to create an experimental interaction between myocardium and foreign mesenchyme. The results showed that after 48 h of tissue interactions the ventricular myocardium is incorporated into the mesenchyme of the anterior chick limb, changing its organization and cytological appearance. The myocytes tend to dissociate, exhibiting a less organized myofibrillar pattern. In addition, abundant extracellular matrix components made up of granular and fibrillar material were observed associated with the myocardial and the mesenchymal cell membranes as well as distributed in their surrounding microenvironment. The endocardium became discontinuous, due to detachment of the cells and emitted multiple pseudopodia and filopodia. These observations indicate that the mesenchyme from the anterior chick limb modifies the cellular behaviour and organization of the neighbouring myocardium and endocardium with which it interacts. We suggest that this might occur through participation of extracellular matrix components such as glycosaminoglycans, fibronectin and collagen which are known to act as macromolecular mediators in cell to cell interactions, cell migration and differentiation.

Animals↗
PubMed1987

Studies on the origin-specific DNA-binding domain of simian virus 40 large T antigen.

The origin-specific DNA-binding domain of simian virus 40 large T antigen was analyzed, and its C-terminal boundary was found to be at or before amino acid 259. This does not include the zinc finger structural motif located at amino acids 302 to 320 (J. M. Berg, Science 232:485-486, 1986). Interestingly, N-terminal fragments of 266 and 272 amino acids and larger displayed dramatically reduced origin-binding activity. In addition, the specific DNA-binding properties of truncated proteins purified from both bacterial and mammalian sources were compared. Truncated T antigens from mammalian cells bound specific DNA fragments more efficiently than did their bacterial counterparts. These results implicate posttranslational modification with a role in regulating the DNA-binding activity of large T antigen.

Animals↗
PubMed1987

Further clinical experience with the silicone tracheal cannula in obstructive sleep apnea.

We report on the perioperative and postoperative course of 47 patients with severe obstructive sleep apnea, who underwent tracheostomy by use of a silicone tracheal cannula developed by Dr. William Montgomery. Our initial experience with the first 20 of these patients (presented in 1982) was quite favorable because of the ease of insertion and care, a high degree of patient acceptance, and infrequent complications. With our current sample, larger experience, and more prolonged follow-up, we noted that symptomatic granulation tissue formation, with or without wound infection, occurred more frequently than was initially appreciated. In 21% (10 of 47) of the cases, the only way to resolve this problem was to remove this device and replace it permanently with a metal (or other type) tracheostomy tube. Other complications included tracheal narrowing and cannula malpositioning and fragmentation. This full report lists in detail the incidence of complications associated with our use of this cannula and modifications which may lessen these.

Adult↗
PubMed1987

Epistaxis: medical versus surgical therapy: a comparison of efficacy, complications, and economic considerations.

A retrospective review of 4 years experience with over 32 epistaxis patients requiring hospitalization and using a standard medical or surgical therapy for control is presented. Medical therapy included the use of anterior nasal packing alone or in association with intranasal and nasopharyngeal balloon tamponade. Surgical therapy, for the most part, consisted of ethmoid and/or internal maxillary artery ligations. Most patients were treated initially with packing and balloons. Fifty-two percent of the group failed this therapy and required ligations for control. The patients who did not come to operation had fewer complications, a shorter average hospital stay, and lower average cost of hospitalization without increased risk of future epistaxis. An analysis is made comparing the results, complications, and financial implications of these two approaches.

Adult↗
PubMed1986

Guanfacine as monotherapy for systemic hypertension.

Three clinical studies examined the effects of guanfacine as monotherapy. Study 1 was a double-blind, randomized, parallel trial with a placebo control with 26 patients with mild essential hypertension treated with 1-mg guanfacine or matching placebo daily at bedtime for 8 weeks. Pretreatment and posttreatment determinations of plasma volume, plasma aldosterone and blood pressure (BP) were made in all 26 patients. There were no significant differences between guanfacine and placebo with regard to changes in plasma volume or plasma aldosterone, but a significant decrease (p = 0.001) in both diastolic and mean BPs was seen with the active drug. No side effects were reported. From this study, it was concluded that guanfacine monotherapy is an effective and well-tolerated initial treatment for mild essential hypertension with no effect on either plasma volume or plasma aldosterone. Study 2 was a double-blind, randomized, parallel clinical study with placebo control with 42 patients with mild essential hypertension treated with either guanfacine (1 mg/day) or matching placebo at bedtime for 8 weeks. Pretreatment and posttreatment evaluations of serum cholesterol, triglycerides, low density lipoproteins, very low density lipoproteins and high density lipoproteins revealed no significant differences between the treatment and the placebo groups. A statistically significant (p less than 0.0001) decrease in diastolic BP was seen in the guanfacine group compared with those patients who received placebo. Guanfacine monotherapy was again shown to be an effective initial treatment for mild essential hypertension with no adverse influence on serum lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Rescue of a tk-plasmid from transgenic mice reveals its episomal transmission.

This communication demonstrates the usefulness of the plasmid rescue procedure for recovery of plasmids from transgenic mice. We have microinjected the plasmid pSK1 harbouring the Herpes simplex virus thymidine kinase gene into fertilized mouse oocytes and succeeded in recovering plasmids from newborns by transformation of E. coli either with HindIII cut cellular DNA or with uncut DNA. The majority of the rescued plasmids were indistinguishable from pSK1 by restriction analysis. The rescued plasmids proved to be functionally active in a transient expression assay in mouse Ltk- cells. The pSK1 DNA sequences were inherited by up to 90% of the second generation progeny mice, which is not in agreement with a Mendelian transmission of heterozygous markers integrated into a single site of the chromosome. These data support the assumption that germ line transmission of non-integrated episomal plasmids can occur.

Animals↗
PubMed1986

Efficient oligodeoxyribonucleotide-directed deletion mutagenesis using pEMBL vectors: removal of early region introns from polyoma virus mutants.

We have used oligodeoxyribonucleotide-directed deletion mutagenesis to remove early region introns from polyoma virus mutants. To this end we compared single priming, double priming, and gapped duplex approaches using either priming at 37 degrees C or at the critical temperature. The gapped duplex approach, coupled with priming at the critical temperature, resulted in up to 70% yield of the desired product. In conjunction with the use of the pEMBL vector system this method was simplified to yield specific deletions from cloned large DNA fragments with high efficiency. The resulting mutant plasmids could be used directly for biological assays without retransformation or recloning. RNA and protein analyses showed that removal of the large T- or middle T-antigen introns from polyoma early region mutants dl23 and dl8 was specific and resulted in DNA competent for the synthesis of only one T antigen.

Antigens, Viral, Tumor↗
PubMed1986

Elongated styloid process syndrome masquerading as pain of dental origin.

An elongated styloid process may be a source of craniofacial and cervical pain. This condition is characterized by a dull, nagging, pharyngeal pain and a palpatory finding in the tonsillar fossa. Sometimes the pain is localized, or radiates to the jaw and ear and may simulate pain of dental origin. Radiographic demonstration of styloid elongation is readily made in most instances. The only effective treatment is surgical shortening of the styloid process. Eight patients undergoing surgery for elongated styloids are reported. Six were previously treated under an incorrect diagnosis such as oral, dental or temporomandibular disease, and subsequently mostly inappropriate dental treatments and exodontia were performed. An evaluation of the intraoral versus the external approach is presented. The few and isolated reported cases of stylalgia masquerading as dental pain and the ensuing mistreatment warranted the writing of this paper.

Adult↗