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Biomedical subjects

O Kaplan

Publications and source records attributed to O Kaplan.

88 records · Page 5Linked to original sources

Aortic valve replacement in septuagenarians.

To evaluate the risk factors of aortic valve replacement (AVR) in the elderly, 35 patients over the age of 70 who had undergone this procedure were reviewed. Twenty-four patients had isolated AVR, three had double valve replacement, seven had a combined procedure of AVR and aortocoronary bypass, and one had AVR and open mitral commissurotomy. There were 27 elective and eight emergency operations. Nineteen patients were in the New York Heart Association (NYHA) Class III, and 16 patients were in NYHA Class IV preoperatively. Hospital mortality was 7.4% (two cases) in the elective group, and 337.5% (three cases) in the emergency group. The major risk factors were found to be the urgency of operation and left ventricular failure associated with severe pulmonary hypertension. There was no postoperative mortality among the seven patients who underwent the combined procedures of AVR and aortocoronary bypass. Follow-up of survivors revealed that 90% returned to NYHA Class I or II, and have an improved lifestyle. Our data suggest that elective AVR is a safe beneficial operation in septuagenarians. Emergency surgery and severe left ventricular failure contribute to high mortality; therefore, AVR should be performed in septuagenarians as early as indicated.

Journal Article↗

A correlation between oestrogen receptors and tumour size in primary breast cancer.

Oestrogen receptor (OR) assay has an essential role in selecting therapy for breast cancer patients, OR status is probably also of prognostic value. The correlation between the size of the primary tumour and OR status was evaluated in 100 women with breast cancer. In 72 post-menopausal patients the OR average level was significantly higher in large primary tumours--T2, T3, when compared to OR levels of T1 tumours. In the 28 pre-menopausal women, this difference was not statistically significant. No correlation between OR level and stage of disease was found. Women presenting with large primary tumours do not necessarily have a poor prognosis.

Adult↗

Octreotide for treatment of postoperative alimentary tract fistulas.

Eighteen patients with postoperative fistulas of the gastrointestinal tract were treated with the somatostatin analog octreotide between November 1989 and November 1992. Fourteen patients had enterocutaneous fistulas: seven from the duodenum and seven from the ileum. Another three patients had pancreatic fistulas, and one patient had a biliary fistula. Within 24 hours of octreotide treatment, a mean reduction of 52% in the intestinal fistulas' output, 40% in the pancreatic fistulas, and 30% in the biliary fistula was noted. In the intestinal fistulas group the closure rate was 72% after a mean of 11 days. Early closure (mean 6 days) was achieved in all three pancreatic fistulas. In the patient with the biliary fistula a 30% reduction was observed twice following the administration of octreotide, and an increase occurred when it was withheld. The reduction rate of the secretions in high-output intestinal fistulas (> 500 ml/day) was higher than in the low-output fistulas (63 +/- 8% versus 39 +/- 4%, p < 0.05). Fistula output and the initial response to octreotide treatment had no value in predicting spontaneous healing. In conclusion, octreotide is a valuable tool for the conservative treatment of fistulas of the digestive tract. It is especially valuable for management of high-output enteric fistulas and pancreatic fistulas.

Anti-Bacterial Agents↗

In vitro and in vivo effects of photodynamic therapy on murine malignant melanoma.

BACKGROUND: The role of photodynamic therapy (PDT) in the treatment of malignant melanoma is not well defined, nor is it known whether the dark melanoma cells absorb the light used in PDT. METHODS IN VITRO STUDIES: 2 x 10(5) B16 murine melanoma cells were incubated with aluminum phthalocyanine (AlpcS4, 2.5 mg/kg) and were then subjected to photoradiation (50, 100 or 200 J/cm2). Viability was then assessed. In vivo studies: HISTOLOGY: C57/B1 mice received 2 x 10(5) B16 cells subcutaneously and were randomized into study (PDT) and three control groups. AlpcS4 2.5 mg/kg was injected intraperitoneally and the mice were exposed to light (100 J/cm2). After 24 hours they were sacrificed and underwent autopsies. Survival: 40 mice were randomized into PDT (40 J/cm2) and control groups and were monitored for 50 days. Tumor growth: 40 mice were randomized into one control and three treatment groups (PDT on day 3, 6, or 12 after injection with B16 cells), and were monitored for 50 days. Temperature: Tumor temperatures before and at the end of PDT were recorded. RESULTS IN VITRO STUDIES: PDT caused a decrease in cell viability to 15.5 +/- 0.7%, 11.5 +/- 2.1%, and 1.5 +/- 0.7% (at 50, 100, and 200 J/cm2, respectively; P < .001). A significant reduction in thymidine incorporation was noted at all energy levels. In vivo studies: HISTOLOGY: PDT caused massive tumor necrosis. Survival: PDT prolonged the survival of mice (41 +/- 13.4 days) compared to controls (15.8 +/- 3.8 days, P < .001). Tumor growth: 31 days after injection with B16 cells, the tumor size was 2.6 +/- 0.3 cm in the control group and 1.6 +/- 0.2, 0.9 +/- 0.3, and 1.0 +/- 0.4 cm in the PDT groups (days 3, 6 and 12, respectively; P < .01). Temperature: PDT increased skin temperature to 42.8 degrees C +/- 1.3 degrees C, 45.3 degrees C +/- 3.5 degrees C, and 51.7 degrees C +/- 2.7 degrees C at 40, 60, and 100 J/cm2, respectively (P < .01). CONCLUSIONS: Photodynamic therapy was found to have significant effects in experimental melanoma in mice. The role of PDT in human melanoma remains to be studied.

Animals↗

The effects of target and distractor familiarity on visual search in anxious children: latent inhibition and novel pop-out.

Children and adolescents (ages 6-17 years) diagnosed as having an anxiety disorder were compared to matched controls on a two-stage serial visual search task in which they identified presence or absence of a unique shape presented with homogeneous distractors. Response time was examined as a function of prior experience with either target, distractor, or both, allowing for a within-subject assessment of latent inhibition (LI: slower responding to a target that was formerly a distractor against a background of distractors that were formerly targets as compared to a novel target with distractors that were formerly targets) and novel pop-out effects (NPO: faster responding to a novel target against a background of familiar former targets as compared to the condition in which both the target and distractors were novel). There were robust LI and NPO effects for both anxious and control children. However, the predicted interaction between diagnosis and LI condition was not obtained. In general, the results suggest that children with diagnosed anxiety disorder do not differ from controls on basic information processing as assessed by this visual search task.

Adolescent↗

Effect of photodynamic therapy on normal fibroblasts and colon anastomotic healing in mice.

Photodynamic therapy as an adjuvant modality to surgical resection of colon cancer is feasible provided that it does not affect healing of the anastomosis. The aim of this study was to evaluate the effects of photodynamic therapy on the viability of normal fibroblasts and on the healing process of colonic anastomosis in mice. Both in vitro and in vivo methods were employed. For in vitro study, 2 x 10(to the fifth power); human fibroblasts were incubated in triplicate with 5-aminolevulinic acid (2.5 microg/well) for 48 hours. Cells then underwent photoradiation at light doses of 50, 100, and 200 joules/cm(2) using a nonlaser light source. Viability was assessed by methylene blue dye exclusion. For in vivo studies, 60 mice were randomized into study and control groups and underwent laparotomy involving colonic anastomosis. The anastomosis underwent photodynamic therapy using 5-aminolevulinic acid (60 mg/kg) as a photosensitizer and a nonlaser light (40 joules/cm(2)). On postoperative days 1, 4, 7, 14, and 21, six mice were killed and subjected to bursting pressure and histologic examinations. Results of in vitro study showed pretreatment cell viability to be 96% to 99% in both groups. Photodynamic therapy caused no significant change in fibroblast viability at all light doses. Results of in vivo studies showed that the mean bursting pressure of both groups dropped to a low peak on day 4. Subsequently there was a gradual increase in bursting pressure along the examined time points (P <0. 001). There was no difference in bursting pressure between the two groups for all time points examined. It was concluded that photodynamic therapy has no effect on viability of normal human fibroblasts and no adverse effects on healing of colonic anastomosis.

Aminolevulinic Acid↗

HGF/SF activates glycolysis and oxidative phosphorylation in DA3 murine mammary cancer cells.

Hepatocyte growth factor/scatter factor (HGF/SF) is a paracrine growth factor which increases cellular motility and has also been implicated in tumor development and progression and in angiogenesis. Little is known about the metabolic alteration induced in cells following Met-HGF/SF signal transduction. The hypothesis that HGF/SF alters the energy metabolism of cancer cells was investigated in perfused DA3 murine mammary cancer cells by nuclear magnetic resonance (NMR) spectroscopy, oxygen and glucose consumption assays and confocal laser scanning microscopy (CLSM). 31P NMR demonstrated that HGF/SF induced remarkable alterations in phospholipid metabolites, and enhanced the rate of glucose phosphorylation (P < .05). 13C NMR measurements, using [13C1]-glucose-enriched medium, showed that HGS/SF reduced the steady state levels of glucose and elevated those of lactate (P < .05). In addition, HGF/SF treatment increased oxygen consumption from 0.58+/-0.02 to 0.71+/-0.03 micromol/hour per milligram protein (P < .05). However, it decreased CO2 levels, and attenuated pH decrease. The mechanisms of these unexpected effects were delineated by CLSM, using NAD(P)H fluorescence measurements, which showed that HGF/SF increased the oxidation of the mitochondrial NAD system. We propose that concomitant with induction of ruffling, HGF/SF enhances both the glycolytic and oxidative phosphorylation pathways of energy production.

Adenocarcinoma↗

Continuous intravenous octreotide treatment for acute experimental pancreatitis.

BACKGROUND: The efficacy of octreotide, the synthetic analogue of the hormone somatostatin, for the treatment of acute pancreatitis is controversial. Octreotide has been commonly administered in subcutaneous bolus injections; however, continuous intravenous infusion may be advantageous for acute conditions. METHODS: Acute experimental pancreatitis was induced in rats by intraparenchymal injections of 1 ml 10% sodium taurocholate, and octreotide (1 microg/kg/h, dissolved in physiological solution, intravenously was started 4 h later and continuously infused for 48 h. Physiological solution infusions, in identical volumes, were used in the controls. The following parameters were examined: mortality; macroscopic and histological damage; hematocrit; plasma pH; acid-base balance; serum glucose; calcium, and amylase. RESULTS: Octreotide treatment had a striking effect on mortality: 8.3 versus 91.6% in the treatment and control groups, respectively (p < 0.001). Octreotide also ameliorated pancreatic edema and intestinal dilatation, and had significant beneficial effects on histopathological damage and the biochemical alterations which are associated with acute pancreatitis. CONCLUSIONS: Continuous intravenous octreotide infusion is a potentially efficacious therapeutic method for acute pancreatitis.

Acute Disease↗

Massive arterial air embolism during cardiopulmonary bypass.

Massive arterial air embolism occurred in two patients during 1250 open heart operations. Emergency measures led to complete recovery in both cases. Flow reversal, hypothermia and anti-oedema measures may be adequate in some clinical situations for total recovery after this catastrophic accident.

Cardiopulmonary Bypass↗