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Biomedical subjects

S Stern

Publications and source records attributed to S Stern.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Findings of automatic border detection in subjects with left ventricular diastolic dysfunction by Doppler echocardiography.

Left ventricular automatic border detection (ABD) patterns were defined in the parasternal short-axis and the apical four-chamber views and were compared with pulsed-wave diastolic Doppler flow-velocity patterns of the mitral valve in 49 subjects (aged 39 to 87 years), 10 selected normal individuals, and 39 consecutive patients with high-quality echocardiographic Doppler studies and relaxation abnormalities (Doppler peak early diastolic velocity/peak late velocity ratio < 1). Both short-axis and apical four-chamber views were useful in the assessment of diastolic function by ABD. However, in subjects with high-quality two-dimensional echocardiographic Doppler studies, ABD was technically more feasible in the apical four-chamber view (97%; 38/39 subjects) than in the short-axis view (64%; 25/39 subjects) and correlated better with Doppler parameters. Compared with normal subjects, patients with abnormal Doppler relaxation patterns showed significant differences in diastolic filling indexes obtained by the ABD technique. The ratio of peak rapid filling rate/peak atrial filling rate (PRFR/PAFR) obtained from the dA/dt waveform in the apical four-chamber view had the highest correlation with Doppler indexes (r = 0.79). A PRFR/PAFR ratio of 1.5 best discriminated between normal individuals and subjects with relaxation abnormalities, with high sensitivity and specificity (95% and 100%, respectively). The PRFR/PAFR ratio obtained from the dA/dt waveform seemed to be a simple and useful method to distinguish between normal and abnormal left ventricular diastolic filling, as defined by Doppler echocardiography.

Blood Flow Velocity↗
PubMedDate not supplied

Is prophylactic diabetic foot surgery dangerous?

Any treatment rendered to the deformed, insensate foot should be undertaken with the prime intentions of reducing the potential for future limb-threatening events and allowing the patient to continue as an ambulatory, productive member of society. The purpose of this article is to compare morbidity and outcomes of elective foot surgery among diabetics and nondiabetics with isolated toe deformities. We compared the prevalence of infection, wound complication, and recurrence of ulcers in 31 diabetics and 33 nondiabetics. All of these patients received a single proximal interphalangeal joint arthroplasty with a mean follow-up of 3 years (range 12 to 61 months). The diabetic group was divided into two subgroups: 1) insensate with deformity, but no history of ulceration, and 2) insensate with deformity and a previous history of ulceration. Diabetics with a history of ulceration were more likely to experience a postoperative infection (14.3%) than neuropathic diabetic patients with no history of ulceration (0%) and nondiabetic subjects (0%) (p = 0.04, Cl = 3.1 to 8.6). There was not a significant difference in prevalence of dehiscence among diabetic and nondiabetic groups (16.1% versus 9.1%, respectively, Cl = 0.4 to 8.8). The long-term outcomes after prophylactic surgery at a site of previous ulceration were uniformly good, with 96.3% of patients remaining ulcer-free a mean of 3 years postoperatively.

Aged↗
PubMedDate not supplied

[In vitro oxygen-dependent survival of 2 human cell lines after radiation combined with tirapazamine (SR-4233) and cisplatin].

Recent data have shown that the in vitro and in vivo cytotoxicity of bioreductive drugs could be significantly increased by combination with ionising radiation or chemotherapy. Various parameters such as oxygen tension and timing of administration of the drugs could play a crucial role in the efficacy of combined treatment modalities. The aim of this study was to define the oxygen dependency of cell survival after in vitro irradiation and incubation with tirapazamine, a bioreductive drug, and cisplatin given alone or simultaneously. Two human cell lines were studied: one cell line sensitive to tirapazamine, Na11+, a pigmented melanoma with a high percentage of hypoxic cells, and a less sensitive cell line to tirapazamine, HRT18, a rectal adenocarcinoma. Gas changes were made to study cell survival at four different oxygen concentrations (pO2): air (20.9% O2), 10.2 and 0.2% O2. Cells were incubated with tirapazamine and cisplatin alone or combined for one hour at 37 degrees C, then irradiated and cultured. For Na11+, cell survival after irradiation was comparable in air and at 10% oxygen with the two drugs given alone or combined. At 2 and 0.2% oxygen, cell killing was largely increased by tirapazamine and was not modified by the addition of cisplatin. For HRT18, cell survival was not modified when cisplatin was added to radiation, whatever the oxygen partial pressure. At low pO2 (2 and 0.2%) the cytotoxic effect of tirapazamine was not significantly decreased by the addition of cisplatin. When cytotoxic and bioreductive drugs are combined to radiation, the magnitude of the observed effect is highly dependent on the partial oxygen pressure and on the sensitivity of the cell line to the individual drugs. This has very important implications for clinical strategies based on combined chemo-radiotherapy.

Antineoplastic Agents↗
PubMedDate not supplied

[Total endoprosthetic management of the hip joint after failed osteosynthesis of para-articular hip fracture].

OBJECTIVE: Treatment of fractures of the proximal femur by open reduction and internal fixation is prone to complications and frequently requiring secondary joint replacement. The aim of the present study was to examine the results of total hip arthroplasty as a salvage procedure for failed internal fixation of femoral or acetabular fractures. PATIENTS AND METHODS: We retrospectively studied 145 patients who had undergone 146 total hip arthroplasties for failed internal fixation of femoral (n = 135) or acetabular fractures (n = 11). Mean follow-up time after insertion of the hip endoprosthesis was 7.1 years (1.5-14.7 years). Patient evaluation included a history, clinical examination, and standard radiographs. RESULTS: Twenty-eight patients had died, and 18 patients were lost to follow-up. Kaplan-Meier analysis with revision of the implants as the end-point demonstrated 85 percent survival after ten years. Using the Merle d'Aubigné rating system, we found good or excellent results in 85 percent of the cases. However, only 73.9 percent of the patients were satisfied with their result, and 40.9 percent still showed a positive Trendelenburg gait at follow-up. The perioperative mortality was 2.7 percent. Surgery-related femoral fractures or fissures were observed in 18 cases, and deep infections in four. CONCLUSIONS: In comparison with data of patients who had undergone primary total hip arthroplasty for osteoarthritis in our department, the results reported here after secondary hip replacement are clearly inferior. Nonetheless, alloarthroplasty of the hip still is the most effective procedure after failed internal fixation for acetabular or proximal femoral fractures.

Adult↗
PubMedDate not supplied

An oligonucleotide analog approach to the decoding region of 16S rRNA.

Despite the passage of about 30 years since the discovery of the translational activities of ribosomes and the outlining of the roles of the large and small subunits, the actual molecular basis for the mRNA decoding activities of the small subunit has remained essentially obscure. In this paper, we describe a new approach using oligonucleotide analogs of 16S ribosomal RNA, in which the small ribosomal subunit is effectively deconstructed into a smaller more experimentally tractable form. Specifically, we review the results of experiments using an oligonucleotide analog of the decoding region of 16S ribosomal RNA, suggesting that the decoding region is the functional core of the small subunit, that it contacts both mRNA codons and tRNA anticodons, and that it mediates and probably enhances codon-anticodon base pairing, that is, decoding.

Base Sequence↗
PubMedDate not supplied

The effect of chronic propranolol therapy on regional cerebral blood flow in hypertensive patients.

In 31 hypertensive patients the effect of chronic oral administration of the beta blocking agent propranolol on regional cerebral blood flow (rCBF) was studied, using the non-invasive 133Xenon inhalation technique. The results of the measurements were compared to the rCBF obtained in an age-matched normal control group. Our study shows that during long-term therapy with low doses of propranolol (less than 120 mg/daily) the rCBF is unaffected, but it is increased significantly if higher doses (greater than 120 mg/daily) are used. In all six patients who served as their own control, as they had basic rCBF measurements before or during low-dose propranolol, the rCBF on high-dose propranolol became significantly increased. The possible mechanisms which may cause the increased rCBF on high-dose propranolol are discussed.

Administration, Oral↗
PubMedDate not supplied

Childhood malignant thymoma: clinical, therapeutic, and immunohistochemical considerations.

Malignant thymomas are among the least common mediastinal tumors in the pediatric age group. Thymomas are considered malignant on the basis of macroscopic and microscopic invasiveness. As only 20 well-documented cases involving children have been reported in the literature, the pattern of responsiveness to therapy and the value of prognostic signs is obscure. Two cases of malignant pediatric thymomas are reported with pathognomonic histoimmunological features of aggressive thymoma. One was cured, with a follow-up of 70 months, and one died while on therapy. Analysis of the histological features and the immunoperoxidase staining displays the complexity of pediatric thymomas and the inability to prognosticate the outcome, respectively.

Adolescent↗
PubMedDate not supplied

Surgery for tricuspid valve disease.

Sixty patients underwent repair or replacement of the tricuspid valve, 58 for acquired and two for congenital lesions. In 59 of the cases, the tricuspid surgery formed part of multiple valve surgery. Preoperatively, 33 patients (55%) were in New York Heart Association class IV and 25 in class III functional capacity. The tricuspid valve was replaced in 42 patients and repaired in 18. Forty-seven patients (78%) survived operation, but 10 of these died during a follow-up period of two to seven years. Thirty-four of the 37 long-term survivors show marked improvement. Operative mortality was 26% for tricuspid valve replacement and 11% for repair; late mortality was 14% and 22%, respectively. It should be stressed that the tricuspid valve replacement group consisted of patients whose preoperative condition was worse and whose valvular pathology was more severe than that of those who had tricuspid repair. In view of this, and the better long-term results of tricuspid valve replacement, it is concluded that the procedure of choice for serious organic disease of the tricuspid valve is valve replacement.

Adolescent↗