Biomedical subjects

F Lewin

Publications and source records attributed to F Lewin.

At least 19 recordsLinked to original sources

PubMed1998

Smoking tobacco, oral snuff, and alcohol in the etiology of squamous cell carcinoma of the head and neck: a population-based case-referent study in Sweden.

BACKGROUND: This case-referent study was conducted to elucidate the role of selected exogenous agents in the etiology of head and neck cancer. The factors studied were tobacco smoking, alcohol intake, the use of moist oral snuff, dietary factors, occupational exposures, and oral hygiene. In this first report, the authors discuss the impact of tobacco smoking, the use of oral snuff, and alcohol consumption. METHODS: The study base was approximately 2 million person-years at risk and consisted of Swedish males age 40-79 years living in 2 geographic regions during the years 1988-1990. A total of 605 cases were identified in the base, and 756 controls were selected by stratified random sampling from population registries covering the base. RESULTS: Among those who were tobacco smokers at the time of the study, the relative risk of head and neck cancer was 6.5% (95% confidence interval, 4.4-9.5%). After cessation of smoking, the risk gradually declined, and no excess risk was found after 20 years. The relative risk associated with alcohol consumption of 50 grams or more per day versus less than 10 grams per day was 5.5% (95% confidence interval, 3.1-9.6%). An almost multiplicative effect was found for tobacco smoking and alcohol consumption. CONCLUSIONS: Tobacco smoking and alcohol intake had a strong interactive effect on the risk of squamous cell carcinoma of the head and neck. Moderate alcohol intake (10-19 grams per day) had little or no effect among nonsmokers. No increased risk was found for the use of Swedish oral snuff.

Adult↗

PubMed1998

Cisplatin-induced inhibition of p34cdc2 is abolished by 5-fluorouracil.

Clinical (Dimery and Hong, J Nat Cancer Inst 1993; 85: 95- 111) and experimental studies (Scanlon et al., Proc Natl Acad Sci USA 1986; 83: 8923-5; Lewin et al., In Vivo 1990; 4: 277-82) have indicated an increased cytotoxic effect, when cisplatin (CDDP) is combined with 5-fluorouracil (5-FU). Addition of 5-FU abolishes the G2-arrest induced by CDDP (Lewin et al., In Vivo 1990; 4: 277-82; Nylén et al., Acta Oncol 1996; 35: 229 35). The mechanism for the synergy is unclear. Activation of p34cdc2 is necessary for progression from G2 to mitosis (Lewin et al., Anti-Cancer Drugs 1995; 6: 465-70). The aim was to study p34cdc2, cdc25C and weel after treatment of mammalian tumour cells in vivo with CDDP as single agent or in combination with 5-FU. CDDP prevented activation of p34cdc2 by keeping cdc25C inactive and weel active. Addition of 5-FU to CDDP decreased the expression of weel and promoted cdc25C-activation. p34cdc2 was dephosphorylated by cdc25C and activated. Alterations in activity of cdc25C and weel after drug combination were due to changes in the protein amount, rather than to changes in the phosphorylation degree.

Animals↗

PubMed1998

Occupational exposures and squamous cell carcinoma of the oral cavity, pharynx, larynx, and oesophagus: a case-control study in Sweden.

OBJECTIVES: This community based case-referent study was initiated to investigate aetiological factors for squamous cell carcinoma of the upper gastrointestinal tract. METHODS: The study was based on all Swedish men aged 40-79 living in two regions of Sweden during 1988-90. Within that base, efforts were made to identify all incident cases of squamous cell carcinoma of the oral cavity, oropharynx and hypopharynx, larynx, and oesophagus. Referents were selected as a stratified (age, region) random sample of the base. The response was 90% among cases and 85% among referents. There were 545 cases and 641 referents in the final study group. The study subjects were interviewed about several lifestyle factors and a life history of occupations and work tasks. The exposure to 17 specific agents were coded by an occupational hygienist. The relative risk (RR) of cancer was calculated by logistic regression, standardising for age, geographical region, and alcohol and tobacco consumption. RESULTS: Exposure to asbestos was associated with an increased risk of laryngeal cancer, and a dose-response relation was present. The RR was 1.8 (95% confidence interval (95% CI) 1.1 to 3.0) in the highest exposure group. More than eight years of exposure to welding fumes was associated with an increased risk of pharyngeal cancer (RR 2.3 (1.1 to 4.7)), and laryngeal cancer (RR 2.0 (1.0 to 3.7)). There were indications of a dose-response for duration of exposure. Associations were also found for high exposure to polycyclic aromatic hydrocarbons (PAHs) and oesophageal cancer, RR 1.9 (1.1 to 3.2). Exposure to wood dust was associated with a decreased risk of cancer at the studied sites. CONCLUSIONS: Some of the present findings confirm known or suspected associations--such as asbestos and laryngeal cancer. The study indicates that welding may cause an increased risk of pharyngeal as well as laryngeal cancer. The findings corroborate an association between exposure to PAHs and oesophageal cancer.

Adult↗

PubMed1998

[Agenesis of the corpus callosum. Neuropathologic study and physiopathologic hypotheses].

The neuropathological study of corpus callosum agenesis requires a two-phase approach: first it should analyze the putative causal factors, i.e. absence of callosal neurons, commissuration inability or synapse remodelling defect; secondly it has to detect any morphogenetic effects stemming from the absence of commissure such as nonregression of archicortical structures, ventricular enlargement or possible invasion of the remaining telencephaplic commissure by callosal neurons. Absence of callosal neurons due to abnormal corticogenesis gives rise to corpus callosum agenesis without callosal axon, that is without Probst's bundles. Conversely, corpus callosum agenesis occurring secondary to a commissuration default is associated with the presence of callosal axons which travel along the midline instead of crossing, that leads to the formation of Probst's bundles. This inability to cross the midline could be secondary to an obstacle, such as lipoma or as interhemispheric cysts, or primitive due to axonal guidance disturbance. In the latter situation, the commissural defect could affect the other cerebral commissures i.e. anterior or hippocampal commissures, or could become integrated into a more diffuse midline pathology involving both cerebral and extracerebral structures. Finally, it could be assumed that a synapse remodelling defect could lead to atrophy or hypertrophy of the commissure, that occurs in the absence of white matter pathology.

Agenesis of Corpus Callosum↗

PubMed1998

[Obstetrical management of agenesis of the corpus callosum].

We present a multicenter analysis of 24 cases of prenatal diagnosis of corpus callosum agenesis and review the literature concerning prognosis factors for continuing or interrupting pregnancy.

Adult↗

PubMed1998

[Prognosis of isolated agenesis of the corpus callosum].

We report preliminary results of a three year follow-up of ten children affected with apparently isolated corpus callosum agenesis (prenatal diagnosis). This population was collected from a multicenter prospective study: annual survey included physical examination, developmental outcome and psychometric evaluation. Febril convulsions appeared to be more frequent than in the general population; developmental outcome was normal at the last evaluation. Follow-up has to be performed up to 10 years to determine more accurately prognosis of isolated corpus callosum agenesis.

Agenesis of Corpus Callosum↗

PubMed1997

Hypothyroidism after external radiotherapy for head and neck cancer.

PURPOSE: To study the development of thyroid hypofunction in patients with head and neck cancers admitted for external radiotherapy. METHODS AND MATERIALS: Between November 1990 and July 1996, thyroid function was measured in 264 consecutive patients, where the entire thyroid gland or part of it was included in the target volume. The time to development of hypothyroidism (HT) was calculated from the start of the radiotherapy. RESULTS: The median follow-up period was 19 months. Seventeen patients (6%) developed elevated serum thyroid-stimulating hormone levels with depressed (free) thyroxine levels (i.e., clinical HT). Elevated serum thyroid-stimulating hormone level with normal (free) thyroxine levels (i.e., chemical HT) developed in 57 (22%). The median time to clinical HT was 15 months (range: 7 to 32). The median time to chemical HT was also 15 months (range: 2 to 28). The actuarial risk of developing clinical or chemical HT 3 years after treatment was 15 and 40%, respectively. The incidence of chemical HT was significantly higher (p = 0.041) when the whole thyroid was included in the target volume compared to patients where only part of the thyroid was irradiated. The same trend was seen as regards clinical HT (p = 0.063). For those 20 patients who underwent laryngectomy, there was an increased risk of both chemical and clinical HT (p = 0.011 and 0.019, respectively). Increasing age was associated with an increased risk of chemical HT (p = 0.001), but not of clinical HT (p = 0.553). Sex, tumor site, radiation dose, and combination of radiotherapy and chemotherapy were not significant factors for thyroid hypofunction. CONCLUSION: Depressed thyroid function is common after external radiotherapy for cancers of the head and neck. Routine testing for possible thyroid hypofunction should be included in the follow-up procedures, even many years after end of radiotherapy.

Actuarial Analysis↗

PubMed1997

Congenital adenomatoid disease of the lung: prenatal diagnosis and perinatal management

Prenatal ultrasonographic (US) detection of congenital adenomatoid malformation (CAM) was made in 18 fetuses at 17 - 36 weeks' gestation and managed in our institution during a 10-year period (1985-1994). The lesion was left-sided in 13 cases, right-sided in 4, and bilateral in 1. According to Stocker's classification, 12 cases were type I, 4 type II, and 2 type III. The prenatal course was followed with serial US examinations in 13 cases; the size of the lesion was stable in 8 and decreased in 5. Mediastinal shift was usually observed, and amniotic fluid volume was increased in 4 cases. One fetus was aborted. Six infants presented with respiratory distress syndrome and required neonatal surgery; delayed surgery was performed in 9 cases. Spontaneous regression of the lesion was observed on follow-up in 2 cases. Surgery consisted in lobectomy in 8 cases and segmentectomy in 6. The presence of fetal hydrops, type III lesions, and bilateral lung involvement are prenatal factors known to be associated with a poor prognosis. However, this series and a review of the literature suggest that caution should be observed with regard to the initial impression when counseling the parents regarding prognosis.

Journal Article↗

PubMed1997

Neoadjuvant chemotherapy with cisplatin and 5-fluorouracil in advanced squamous cell carcinoma of the head and neck: a randomized phase III study.

BACKGROUND AND PURPOSE: In 1986 a prospective, randomized, multi-centre trial for evaluation of neoadjuvant chemotherapy with cisplatin and 5-fluorouracil in the treatment of advanced squamous cell carcinoma of the head and neck was initiated. As survival in this group of patients is poor the purpose was to find a possible survival benefit of the chemotherapy in addition to radiotherapy compared to radiotherapy only. METHODS: Four-hundred sixty-one patients from Denmark, Norway and Sweden with tumors in oral cavity, oropharynx, hypopharynx and larynx were randomized to receive either standard treatment (radiotherapy or radiotherapy followed by surgery) or neoadjuvant chemotherapy followed by standard treatment. Chemotherapy included three courses of cisplatin 100 mg/m2 i.v. infusion on day 1 followed by 5-fluorouracil 1000 mg/m2 per day continuous i.v. infusion for 120 hours. Radiotherapy 64-70 Gy in 2 Gy per fraction, 5 times/week, was given to patients in both treatment arms. RESULTS: Response rate was 71% for patients randomized to chemotherapy-radiotherapy and 66% for patients randomized to standard treatment (not statistically significant). Residual tumors were excised if possible. After surgery 62% of the patients randomized to chemotherapy-radiotherapy and 60% of the patients in the standard treatment group were clinically tumor free. CONCLUSIONS: No statistically significant benefit in survival was observed for patients treated with neoadjuvant chemotherapy followed by radiotherapy. Nor was there any impact of chemotherapy on the number of patients achieving loco-regional tumor control after primary treatment.

Adult↗

PubMed1997

Single-institution effectiveness assessment of open-heart surgery in octogenarians.

OBJECTIVE: To determine short- and long-term outcome of open-heart surgery in octogenarians. METHODS: We reviewed the medical charts of 130 consecutive octogenarians undergoing open-heart surgery. Patients with significant comorbidity were excluded from the study. The effect of cardiac and operative risk factors on mortality and morbidity was evaluated. General practitioners and cardiologists were contacted in order to obtain information on the patients' current medical and functional status. RESULTS: Operative mortality for valve replacement (VR) and coronary artery bypass grafting (CABG) was 11.5%. Four-year survival was 73.5% with 75.9% still living independently. The relative risk for operative mortality was 4.3 in case of extracorporeal bypass time exceeding 95 min and 3.6 in case of significant left main stem disease. The risk of late death increased 2.5 times at a left ventricular ejection fraction lower than 50%. CONCLUSIONS: Our data match the results of similar studies involving large numbers of patients. When a multicenter data bank is missing, the evaluation of a relatively small patient group can yield information that may be as useful to patient and physician as information obtained by large studies. Open-heart surgery in octogenarians carries an acceptable mortality risk and its effectiveness in terms of improved quality of life is good.

Aged↗

PubMed1997

Congenital adenomatoid disease of the lung: prenatal diagnosis and perinatal management.

Cystic Adenomatoid Malformation of Lung, Congenita↗

PubMed1997

[Prenatal MRI of the brain. Retrospective study apropos of 34 tests].

We performed 34 antenatal MRI, in utero in 29 foetuses with cerebral malformations depicted by US. For five patients, a second antenatal MRI was performed because of a technical failure or of diagnosis doubt. We considered that MRI is a valuable imaging method. We have observed 2 false negatives (myelomeningocele, gyration abnormality) on MR study (n = 34). MRI is more contributive that US for the etiological diagnosis of ventricular enlargement: 83% versus 46%. MRI depicted corpus callosum agenesis misdiagnosed in 5 patients by US. MR results modified the therapeutic procedure in 37% of our patients. We think that the optimal term to perform MRI study is after 28 weeks gestational age because of the size of the fetus and for the timing of cerebral development. Ventricular dilatation (criteria: occipital horn size more that one centimeter at 25 weeks of term) is the main indication of MR study.

Brain↗

PubMed1996

Absence of misincorporation of pyrimidines in DNA after treatment with a combination of cisplatin (CIS-diammine-dichloro-platinum) amd 5-fluorouracil of mouse sarcoma cells.

The effects on incorporation into DNA of the deoxyribonucleotides dCTP and dTTP and the DNA synthesis rate after treatment with cisplatin (CDDP), 5-fluorouracil (5-FU) or a combination of CDDP and 5-FU were studied in ascites sarcoma (Bp8) growing in mice. Single administration of CDDP gave an early (1 h) transient increase in the DNA-synthesis followed by a decrease. 5-FU as single agent did increase the rate of DNA synthesis after 6 h with a maximum at 10 h. The combination of CDDP and 5-FU markedly increased the rate of DNA synthesis up to 6 h as compared to single drug treatment. Although the dCTP pool increased after combined treatment, while the dTTP pool was unchanged, no alterations in the proportions of dTTP and dCTP incorporated into DNA could be detected. Hence, misincorporation of pyrimidines is not the mechanism for the synergistic effect of the combination of CDDP and 5-FU.

Animals↗

PubMed1995

The effect of 5-fluorouracil on cisplatin induced DNA interstrand cross-linking in a mouse ascites tumor growing in vivo.

In earlier studies we showed that a supra-additive cytotoxic effect was obtained with combined treatment with cisplatin and 5-fluorouracil (5-FU) of Bp8 ascites tumor growing in vivo in mice. We therefore studied the DNA interstrand cross-linking after single drug treatment with cisplatin, 5-FU and the drugs combined. The alkaline elution technique was used. 5-FU induced no measurable DNA cross-linking. Cisplatin caused a dose-dependent increase in DNA cross-links 6 h after treatment. When combining cisplatin and 5-FU, no significant change in the number of DNA cross-links was found for this time. The removal of DNA interstrand cross-links was studied after 24 and 36 h. There was no difference in the removal rate between single drug treatment with cisplatin as compared with the combined treatment with the two drugs. Also, the number of DNA single strand breaks (SSB) possibly created when the cisplatin induced cross-links or UV-induced DNA damage were repaired were measured with the alkaline elution technique. No increase in the amount of SSB was seen after combined treatment. Thus, we found no interaction of 5-FU and cisplatin in terms of DNA damage. Other mechanisms for the supra-additive effect found when combining cisplatin and 5-FU have to be considered.

Animals↗

PubMed1994

[Fetal surgery].

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Animals↗

PubMed1994

Amniotic fluid digestive enzymes: diagnostic value in fetal gastrointestinal obstructions.

The diagnostic value of amniotic fluid gamma-glutamyl-transpeptidase (GGTP) and intestinal alkaline phosphatase (iALP) was evaluated in 55 patients who underwent amniocentesis for karyotyping because fetal gastric or small bowel dilatation had been detected by ultrasound. Gastrointestinal malformation was confirmed in 46 cases and there was no gastrointestinal anomaly in nine cases. Prenatal ultrasound was suggestive of gastroduodenal dilatation in 34 cases (group I) and small bowel dilatation in 21 cases (group II). In group I, amniotic fluid GGTP above the 99th percentile was 71 per cent sensitive and 100 per cent specific for a true anatomical defect of the digestive tract (mainly duodenal atresia). In group II, high levels of GGTP and/or iALP were 69 per cent sensitive and 83 per cent specific for a fetal digestive tract anomaly. In other words, when digestive tract dilatations were diagnosed by prenatal sonography, abnormal amniotic fluid enzyme activities were strongly suggestive of such an anomaly, the possibility of which was not precluded by normal amniotic fluid iALP and GGTP activities. But amniotic fluid digestive enzyme activities do not help in defining the prognosis.

Alkaline Phosphatase↗

PubMed1994

Management of ovarian cyst detected by prenatal ultrasounds.

As a result of refinements in Prenatal Ultrasonography (US), neonatal ovarian cysts are more frequently encountered than in the past. Between January 1981 and December 1990, 21 consecutive fetuses with ovarian cysts were followed up by ultrasonography. 23 ovarian cysts were diagnosed between 28 and 38 weeks gestation. 18 cysts were initially large cysts (more than 50 mm in diameter). In 9 cases, an anechoic cyst was observed and a US-guided needle aspiration of the cyst was performed (2 antenatally and 7 postnatally). Ultrasonographic patterns of complicated cyst were observed in 3 fetuses. After a postnatal ultrasound control, 11 infants were operated on: 8 surgical interventions were required for complicated cysts (torsion: 4, hemorrhage: 4), 3 cases irrespective of their sonographic appearance in our initial experience. In the remaining cases, spontaneous resolution was followed by repeated ultrasonographic examination. Prenatal ultrasonography today allows diagnosis of ovarian cysts and may suggest antenatal complications. To preserve as much ovarian tissue as possible, cysts greater than 50 mm in diameter should be candidates for percutaneous aspiration and complex cystic masses should be operated on.

Female↗

PubMed1994

DNA synthesis after combined treatment with cisplatin and 5-fluorouracil of a mouse ascites tumor growing in vivo.

We examined whether an increase in the salvage and/or the de novo synthesis of thymidine (TdR) can explain the elevated DNA synthesis rate found up to 15-20 h after combined treatment with cisplatin and 5-fluorouracil (5-FU), compared with single-drug regimen. The salvage and the de novo pathways of TdR in Bp8 mouse ascites tumor cells were reduced equally after the combined treatment and the single-drug treatments. The inhibition of the de novo pathway of TdR was confirmed by a reduced thymidylate synthase activity, as measured in cell extract. A marked imbalance of the deoxyribonucleotide triphosphates were found, in particular between the deoxypyrimidines. These imbalances were similar between the 5-FU single-drug treatment and combined treatment. We conclude that neither the extracellular TdR salvage nor the de novo synthesis of TdR explain the relatively elevated DNA synthesis rate after combined treatment. We suggest that the supra-additive effect of the combined treatment is due to an interaction between the elevated DNA synthesis, the imbalanced deoxyribonucleotides and the cisplatin-induced DNA cross-links, and possibly also due to a higher concentration of 5-FU incorporated into DNA.

Animals↗