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Biomedical subjects

H Stern

Publications and source records attributed to H Stern.

At least 109 records · Page 6Linked to original sources
PubMed1986

Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast.

Transesophageal echocardiography was performed in 314 patients over a period of 24 months using a 3.5 MHz phased-array system fitted to the distal end of a conventional 12 mm endoscope. In 12 patients (2.6%) transesophageal echocardiography could not be performed because of adverse reaction to the gastroscopic procedure. Side effects were a transient A-V block in one patient and asthmatic attack in another. Mitral valve lesions were found in 99 of 314 patients. In 9 of these 99 patients (11%), including 1 patient with mitral valve stenosis and sinus rhythm, 2 with atrial fibrillation, 3 with disc, and 3 with porcine mitral prosthesis, spontaneous echocardiographic contrast was found within the left atrium, described as faint echoes in 2 patients and dense echoes filling the whole left atrium and following turbulent flow in the other 7 patients. Only in 2 patients was left atrium shown to have additional echoes within its cavity in the four-chamber view by transthoracic echocardiography. Signs of cerebral emboli were found in 5 of 9 patients and of peripheral embolism in 3 of 9 patients. Their mechanism seems to involve red cell aggregation, which is greatest at low flow velocity such as in dilated left atria in the case of mitral valve stenosis or prosthesis. The additional effect of platelet aggregation must be discussed because increased platelet aggregation was detected in all patients with spontaneous echocardiographic contrast. Transesophageal echocardiography seems to be of great diagnostic value in patients with mitral valve lesions and cerebral and peripheral embolism, giving new insight into the pathophysiologic mechanism and possibly improving the therapeutic approach in the near future.

Adult↗
PubMed1986

DNA synthesis at selective sites during pachytene in mouse spermatocytes.

DNA repair replication has been previously demonstrated to occur in mouse spermatocytes during the pachytene stage. The results reported in this study provide a more detailed characterization of pachytene repair by focusing upon specific properties of the sites of replication. Our data demonstrate that single-strand breaks persist within replicated sequences throughout a period which corresponds to a defined interval of the pachytene stage. A large fraction of the sites may be nicked more than once within the same DNA strand, allowing the selective release of replicated DNA sequences from gently denatured spermatocyte DNA. DNA fragments thus prepared from pachytene spermatocytes are not of random sequence composition, but are derived from a specific subset of the mouse genome. Sites of replication are also associated with chromatin of distinctive structure in pachytene spermatocytes, as evidenced by the sensitivity of replicated chromatin to DNase II, and its solubility in the presence of Mg2+. In each of these respects, sequences replicated in pachytene spermatocytes closely resemble their counterparts in the Lilium genome.

Animals↗
PubMed1986

Restorative proctocolectomy. Clinical results and manometric findings with long and short rectal cuffs.

Clinical results and manometric findings were compared in 82 patients following restorative proctocolectomy. There were 41 patients with long rectal cuffs measuring 8 to 10 cm. There were 39 J-shaped pouches and 2 S-shaped pouches in this group. Forty-one patients had short rectal cuffs measuring 2 to 3 cm. There were 28 J-shaped pouches and 13 S-shaped pouches in this group. Anal manometry was performed in ten patients with long rectal cuffs and in ten patients with short rectal cuffs matched for age, sex, and stool frequency. Postoperative complications were significantly greater in patients with long rectal cuffs. Functional results and manometric findings were similar. No patient demonstrated a normal rectoanal inhibitory reflex. The data in this study suggest that a short rectal cuff can be used safely for restorative proctocolectomy with satisfactory results. A normal rectoanal inhibitory reflex may be absent after restorative proctocolectomy, and this does not interfere with the attainment of continence.

Adult↗
PubMed1986

Coxsackie B virus-specific IgM antibody and myocardial infarction.

The ELISA technique was shown to be group-specific for the detection of IgM antibodies against coxsackie B viruses, and probably against a wider range of enteroviruses. No evidence was obtained that recent coxsackie B-virus infection predisposes to myocardial infarction.

Antibodies, Viral↗
PubMed1986

General recombination in meiosis.

The meiotic events of homologous pairing and chiasma formation are apparently related to a number of meiotic processes. These include a delayed replication of small portion of genome (zygoDNA). L-protein, present transitionally in meiotic S-phase and leptotene, can bind to the specific sequences of zygo DNAs to form a nick and selectively suppress their replication until zygotene. Other meiosis specific proteins (R-protein, U-protein, rec A-like protein (m-rec) probably related with pairing and recombination but none of these, either alone or combination, is capable of inducing recombination in vitro. We have isolated proteins from meiotic and somatic cells that are capable of recombining two DNA plasmids in vitro. They have been designated m-recombinase and s-recombinase, respectively. m-recombinase appears during meiotic prophase with or without chiasma-formation, suggesting that regulation of meiotic recombination depends, not on the formation of appropriate enzymes but on rendering the enzymes effective by altering chromatin-structure. s-recombinase activity seems to be related to cell division and/or cell differentiation. The assay system used here for necessary recombination may be applicable to various situations.

Animals↗
PubMed1985

Detection of rubella-specific IgM in subclinical rubella reinfection in pregnancy.

Seven cases of asymptomatic rubella reinfection in early pregnancy are described. In each, there was a history of exposure to a rubelliform illness and low levels of rubella-specific IgM subsequently appeared in the serum. Four of the women had been immunised, after having been shown to be susceptible to rubella, one had been immunised at school without previous antibody screening, and two were uncertain about immunisation. One pregnancy was terminated and rubella virus was not isolated from the products of conception. Six pregnancies went to term and the infants showed no evidence of intrauterine infection. In a further case it was impossible to discriminate between reinfection and primary infection, and termination of pregnancy was offered.

Adult↗
PubMed1985

General recombination mechanisms in extracts of meiotic cells.

RecA-like proteins have been purified from somatic and meiotic cells of mouse and lily. The rec proteins have been designated "s-rec" and "m-rec" to indicate their respective tissues of origin. The two proteins differ in molecular weight and in their response to temperature, the latter being consistent with the optimal temperature for physiological function of their tissues of origin. There is a major increase in m-rec protein with the entry of cells into meiosis, the peak of activity being early pachytene. Extracts of the cells and also those of yeast (Saccharomyces cerevisiae) have been prepared that have the capacity to catalyze homologous recombination. These extracts behave similarly to the m-rec proteins upon entry of cells into meiosis. Yeast transferred to sporulation medium displays a 100-fold increase in the recombination activity of the extract at about the time of entry into meiosis. The occurrence of peak levels of m-rec and recombination activity in extracts from cells in early pachytene points strongly to that stage as the time at which the enzymatic phase of recombination occurs.

Animals↗
PubMed1985

Computerized data retrieval system for colon surgery.

Good clinical practice is based on a continuous reevaluation of one's own work as compared with published standards. That which limits particularly the private practitioner from examining and publishing his data, is not the lack of desire, but the scarcity of opportunities and resources to do so. Computers as tools for data retrieval and analysis for research purposes and patient management have been available for some time. They have been of limited utility for most surgeons because of an inhibiting size and/or training period, and illogical design. The authors discuss the limitations of much of the available computer "tools," and present a system, METABASE, specifically designed for colon and rectal surgeons to use in their private practices for data retrieval and analysis.

Colon↗
PubMed1985

The pelvic pouch and ileoanal anastomosis procedure. Surgical technique and initial results.

The pelvic pouch and ileoanal anastomosis procedure should be considered a reasonable alternative for selected patients with ulcerative colitis and familial polyposis. Patients can expect an improved quality of life without a stoma, particularly those with ulcerative colitis. The long-term effects of the reservoir are not completely known; however, from previous reports and from experience with the Kock's ileostomy reservoir, it seems unlikely that there will be a long-term metabolic problems. It appears that a reservoir is essential in adults to minimize stool frequency to an acceptable level and that there is an inverse correlation between pouch size and stool frequency. We still consider this to be an evolutionary procedure and, as such, it should be confined to specialized centers where larger experiences can be accumulated. For the majority of patients who are being considered for proctocolectomy and ileostomy, we urge that they be made aware of alternative forms of therapy and that retaining the rectum should be considered in these patients due to the possibility of reconstructive surgery at a future date.

Adolescent↗
PubMed1985

Meiosis-specific transcripts of a DNA component replicated during chromosome pairing: homology across the phylogenetic spectrum.

In meiotic cells of Lilium, a group of single or low copy number DNA sequences that constitute about 0.1-0.2% of the genome do not replicate during the premeiotic S-phase but do so at zygotene in coordination with chromosome pairing. An appreciable fraction of these sequences has now been found to be transcribed into poly(A)+ RNA when chromosomes initiate the pairing process. This "zygRNA" has not been detected in nonmeiotic tissues. Even within the meiocytes, zygRNA is not detectable prior to leptotene or beyond midpachytene. S1 nuclease digestion of mouse spermatocyte nuclei selectively released zygDNA, which hybridizes with lily zygRNA. zygRNA has not been detected in mouse somatic tissues. The profile of zygRNA formation and disappearance in mouse spermatocytes is very similar to that of zygRNA in lily meiocytes.

Animals↗
PubMed1985

Cardiovascular effects of single doses of the antidepressants amitriptyline and lofepramine in healthy subjects.

In a placebo-controlled double blind study, single oral doses of lofepramine (140 mg and 210 mg) and amitriptyline (100 mg and 150 mg) were given to 5 healthy volunteers. Heart rate, blood pressure, systolic time intervals, and electrical impedance cardiogram were recorded in supine and upright position for 8 hours after drug administration. In addition, plasma drug concentrations were measured simultaneously. Amitriptyline caused a more pronounced increase in heart rate, especially under orthostatic stress, than did lofepramine. Both drugs reduced total peripheral resistance; amitriptyline's effect was greater. A rise in blood pressure (supine position) and shortening of the electromechanical systole under lofepramine indicated an improvement of cardiac performance. In contrast amitriptyline, particularly, in the upright position, lowered blood pressure and lengthened electromechanical systole. Since both drugs have a comparable antidepressant activity, lofepramine is suggested to induce fewer untoward cardiovascular reactions than amitriptyline.

Adult↗
PubMed1985

Antiarrhythmic therapy with flecainide in combination and comparison with propranolol.

In a prospective study of 10 patients with chronic ventricular arrhythmias, flecainide 50mg tid and propranolol 20mg tid were administered, alone and in combination, in a crossover design. Before and after each treatment phase, routine ECG and 24-hour ECG were recorded, morning plasma concentrations of the drugs were measured, and side effects recorded. Treatment with flecainide alone resulted in a 38% mean reduction (p less than 0.05) of ventricular premature complexes, a 75% (p less than 0.01) mean reduction of couplets, and elimination of ventricular tachycardia. At the dosage administered, propranolol alone had no antiarrhythmic effect. The combination of flecainide and propranolol showed no additional therapeutic benefit although there was a small, but not significant, increase in ventricular premature complexes and couplets. Use of flecainide resulted in a 12% widening of the QRS complex, with no significant change in PQ time, QTc and heart rate. Combined therapy with propranolol and flecainide resulted in a 12% decrease of average heart rate. The same effect was achieved when propranolol was given alone. The average plasma concentration of flecainide increased by 25% during combined therapy with propranolol. There were few side effects related to flecainide at the dosage administered and no additional side effects were recorded during the combined treatment.

Adult↗