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Biomedical subjects

B J Smit

Publications and source records attributed to B J Smit.

At least 19 recordsLinked to original sources
PubMed1994

Cocaine use in pregnancy in Amsterdam.

To study the effects of cocaine use in pregnancy in Amsterdam, clinical data on cocaine-using pregnant women (n = 21) and their offspring (n = 23) were obtained retrospectively (1987-1994) at the Academic Medical Center, Amsterdam. Infants exposed to cocaine had a median gestational age of 39 weeks and a median birth weight of 3090 g. There were six preterm infants, two small-for-gestational-age infants and five infants with a small head circumference. Three infants had a congenital malformation. One infant (Potter's syndrome) died shortly before birth. One infant had congenital syphilis, four had intracerebral abnormalities on ultrasound and four had abnormal neurologic symptoms in the neonatal period. One infant died after 21 days of life. At follow-up four infants showed abnormal development. In 12 of the 23 infants (52%), one or more possible effects of cocaine were found.

Child of Impaired Parents↗
PubMed1994

Substance use in pregnancy: do we care?

Two cohorts of substance-using women were compared retrospectively. From 1969 to 1979 a very high perinatal mortality rate (PMR 9.8%) was found among 92 polydrug-using women (1 twin excluded). Preterm delivery occurred in 25% of all pregnancies and in 30% of the children birth weight was below the 10th percentile. Nineteen women using heroin only had a worse fetal outcome (PMR 32%, preterm delivery in 47%, birth weight < 10th percentile in 42%). These results led to a strict surveillance system. In the period 1980-1989, 240 women (4 twins excluded) delivered after 16 weeks. Total fetal loss decreased to 2.1% and PMR to 0.4%, which was similar to results in controls. However, 22% of the women still delivered before 37 weeks and 27% delivered a child < 10th percentile. Methadone-using women were able to halve their dosage during pregnancy and 16 were detoxified. Multivariate analysis within the substance users of the second cohort showed that the neonatal abstinence syndrome, but not the (registered) amount of opiates used, was related to a lower birth weight. Not coping with prenatal care was related to a shorter pregnancy length. Multivariate analysis, including the controls, showed a significant relation of birth weight (345 g lower) with substance use. Also, head circumference was 0.8 cm smaller. Length of pregnancy however was related to smoking. This study shows that it is difficult to make substance users attend prenatal care, but also that women coping with prenatal care reduce substance intake. Opiate use might be responsible for lower birth weight, although not in a clear dose-response relationship, whereas lifestyle, as represented by not coping with prenatal care and the quantity of cigarette smoking, shortens the length of pregnancy.

Adult↗
PubMed1994

Lethal exposure.

Explore the source record for details and available documents.

Environmental Monitoring↗
PubMed1992

Radiotherapy of aggressive fibromatosis.

The long term results of 24 patients treated with postoperative irradiation for aggressive fibromatosis are presented. Tumour sites were the pelvis (8), chest wall (5), shoulder (5), extremities (4) and head and neck (2). Macroscopic complete resection (R1) was performed in 3 cases. 17 patients presented postoperatively with gross disease (R2), 8 of which were recurrent tumours. 4 patients with inoperable disease had biopsies only. Radiation doses ranged from 28 to 64 Gy at a fractionation of 5 x 2 or 4 x 2.5 Gy/week. 4 patients had external irradiation in combination with 192Ir implants, 2 were irradiated with implants alone. In the combined treatment group, external doses ranged from 28 to 52 Gy and additional interstitial doses from 35 to 50 Gy. 192Ir treatment alone was given with 45 and 57 Gy to the contour of the target volume. The 10 year recurrence free survival rate is 75%. A dose response relationship has been established in the dose range of 30-60 Gy revealing an expected 80% persistent tumour control rate at 60 Gy. A dose volume relationship however, could not be derived from our data. Moderate fibrosis without functional impairment developed in 5 patients (21%). These data support a policy of postoperative radiotherapy with 60 Gy in patients with incompletely excised or gross residual tumour following surgery.

Adolescent↗
PubMed1989

The role of neutrons in the treatment of soft tissue sarcomas.

Two-hundred twenty-one patients with soft tissue sarcoma were treated from 1978 to 1983. Treatment was nonrandomized and consisted of neutron irradiation in 94 cases with gross tumor. Treatment was nonrandomized and consisted of neutron boost irradiation after photon-irradiation or electron-irradiation in 127 cases with no gross tumor after surgery. Patient distribution according to UICC (1978) criteria was 15, 100, and 106 of T1, T2, and T3 respectively. Distribution by pathologic grade was 54, 107, and 60 for Grade 1, Grade 2, and Grade 3 tumors. Distribution by tumor residuum after surgery was 23 cases without microscopic disease (R0), 104 with microscopic disease (R1), and 94 with gross residuum (R2) or nonoperative disease. Five-year follow-up reveals a significant difference (P = 0.024) in disease-free survival (DFS) for T1 (60%), T2 (71%), and T3 (29%, P = 0.016) tumors. Similarly, there are significant DFS differences among G 1 (74%), G 2 (48%, P = 0.035), and G 3 lesions (22%, P = 0.024). The impact of tumor bulk or residuum on DFS after operation is significant when comparing R0 (87%) and R1 (65%) disease (P = 0.042). The 5-year survival of patients who had gross residuum (R2) after surgery was significantly worse (26%, P = 0.003). Ninety percent of patients failed treatment locally and distally within 2 years. The late morbidity rate was 27% for neutron and 7% for neutron-boost irradiation. In our series and reported photon data, local control rates for tumors 5 to 10 cm with neutrons were 76% and 53%, respectively. Low energy (d(14) + Be) neutrons are considered beneficial in the postoperative treatment of well-differentiated soft tissue sarcomas where gross tumor remains. Neutron-boost irradiation is of potential benefit in the treatment after operation of T2-3, and G 1-2 tumors if there is microscopic residual tumor.

Adult↗
PubMed1989

[Repatriation of the prematurely born infant].

A preterm birth of a child during a holiday abroad may have serious consequences for child and parents. The neonate's repatriation and the problems it causes are discussed and illustrated by two case histories. The attending midwife, general physician or obstetrician may play a preventive part.

Delivery, Obstetric↗
PubMed1987

Irradiation damage in chromatin isolated from V-79 Chinese hamster lung fibroblasts.

The effect of chromatin structure on the extent of radiation damage induced by low doses of 100 KeV X rays was investigated using a fluorescent assay for DNA unwinding. Chromatin was isolated from V-79 Chinese hamster lung fibroblast nuclei by partial digestion with micrococcal nuclease. Gel electrophoresis of the isolated DNA showed the molecular weight of the chromatin preparation to be 10.6 X 10(6) with a size range of 6.6-21.7 X 10(6) Da while a size of 10.2 +/- 0.9 X 10(6) Da was found by sedimenting the DNA in alkaline sucrose gradients. The repeat length of V-79 chromatin was found to be 194 +/- 3 bp. The typical nucleosomal repeat structure of the isolated chromatin and that of intact nuclei was identical. Irradiation with 50 and 100 Gy of 100 KeV X rays and analysis by alkaline sucrose density centrifugation indicated that V-79 chromatin sustained 0.56 +/- 0.19 and 0.69 +/- 0.09 single-strand breaks per 10 Gy per 10(8) Da of DNA, respectively. Irradiation with doses of 0.5-3.0 Gy of 100 KeV X rays and analysis by the fluorometric assay showed that the radiation sensitivity of V-79 chromatin decreases sharply on compaction with MgCl2. Histone H1 depletion, which inhibits compaction and causes chromatin to expand by increasing the linker from 26 to 48 bp, results in a considerable increase in the radiation sensitivity. It is concluded that radiation damage sustained by DNA is greatly influenced by chromatin structure.

Animals↗