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Biomedical subjects

M Simons

Publications and source records attributed to M Simons.

At least 181 records · Page 10Linked to original sources
PubMed1991

Children who cross cultures.

The subject of this study is the effects of transcultural sojourn and culture shock on the psycho-social development and school achievement of Dutch children. One hundred and three Dutch children in the age range 6-17 years who stayed abroad with their parents for at least two years and returned to Holland were compared with 81 Dutch classmates of the same age and sex. The class teacher and parent(s) were the informants. The transcultural group showed more behavioural problems on the Dutch version of the Child Behavior Checklist developed by Achenbach. Parents of the transcultural group regarded their children on a modified Graham & Rutter questionnaire as less happy than the control parents. However, no differences were found for academic achievement or problem behaviour at school as assessed by the teacher version of the CBCL, the 'Teacher's Report Form' (TRF). Organizations which send their employees abroad should direct more attention to employees' children. Attention given by parents and teachers to language problems and school performance should not pre-empt close attention to the psycho-social development of children.

Adolescent↗
PubMed1991

Human nonmuscle myosin heavy chains are encoded by two genes located on different chromosomes.

We report the cloning of cDNAs encoding two different human nonmuscle myosin heavy chains designated NMMHC-A and NMMHC-B. The mRNAs encoding NMMHC-A and NMMHC-B are both 7.5 kb in size but are shown to be the products of different genes, which are localized to chromosome 22q11.2 and chromosome 17q13, respectively. In aggreement with previously reported results using avian tissues, we show that the mRNAs encoding the two myosin heavy chain isoforms are differentially expressed in rat nonmuscle and muscle tissues as well as in a number of human cell lines. The cDNA sequence encoding the 5' portion of the NMMHC-A isoform completes the previously published 3' cDNA sequence encoding a human myosin heavy chain, thus providing the cDNA sequence encoding the entire NMMHC-A amino acid sequence. Comparison of this sequence to cDNA clones encoding the amino-terminal one third of the NMMHC-B sequence (amino acids 58-718) shows them to be 89% identical at the amino acid level and 74% identical at the nucleotide level.

Amino Acid Sequence↗
PubMed1990

Linkage of a nasopharyngeal carcinoma susceptibility locus to the HLA region.

The frequency of nasopharyngeal carcinoma is nearly 100-fold higher in southern Chinese than in most European populations. Earlier studies have suggested that an increased risk of nasopharyngeal carcinoma is associated with specific haplotypes in the HLA region: relative risks slightly over twofold were found for haplotypes A2, Bw46 and the antigen B17. We now report a linkage study based on affected sib pairs which suggests that a gene closely linked to the HLA locus confers a greatly increased risk of nasopharyngeal carcinoma. The maximum likelihood estimate is of a relative risk of approximately 21. The relationship between this suspected disease susceptibility gene (or genes) and known viral and environmental aetiological factors remains to be elucidated.

China↗
PubMed1990

Multiple hepatic abscesses: cholangiographic changes simulating sclerosing cholangitis and resolution after percutaneous drainage.

A 59-yr-old man developed multiple hepatic abscesses following an episode of diverticulitis. A percutaneous transhepatic cholangiogram (PTC) showed changes typical of sclerosing cholangitis complicated by multiple hepatic abscesses. No biliary tract stones were seen either on ultrasound or PTC. A single drain left in the right biliary tree and a course of intravenous antibiotics resulted in complete normalization within 14 days of the previously involved biliary tree.

Bacteroides Infections↗
PubMed1989

Diagnosis and management of subclavian vein thrombosis occurring in association with subclavian cannulation for hemodialysis.

With the aim of improving the diagnosis and treatment of subclavian vein thrombosis, associated with subclavian cannulation for hemodialysis, we performed Doppler examination of the subclavian vein and clinical inspection of the ipsilateral arm at every dialysis in 50 consecutive patients who received subclavian hemodialysis catheters over 1 year. Edema of the arm and disappearance of the subclavian vein bruit correctly detected 3 cases of subclavian vein obstruction which were confirmed by X-ray venograms. All 3 cases failed to respond to systemic heparin, but were successfully recanalized within 36 h with continuous local streptokinase infusion at a rate of 10,000 U in 1 ml/h. In 4 other cases of edema of the arm, Doppler examination correctly predicted patency of the vein, also confirmed radiologically. In 2 cases of thrombosis, there was an underlying stenosis of the left innominate vein close to its union with the superior vena cava. These were dilated by balloon angioplasty; the stenosis recurred in both cases without recurrent thrombosis, and the angioplasty was repeated. Doppler surveillance seems to be a promising aid to the detection of subclavian vein thrombosis from hemodialysis catheters. Local streptokinase infusion is effective in treating thrombosis. Underlying venous stenosis should be looked for because this may be at least partly remediable by balloon angioplasty.

Angioplasty, Balloon↗
PubMed1989

[Initial dislocation of the patella; which treatment?].

Twenty patients, victims of a first luxation of the patella, were the object of a retrospective study. They were all subjected to arthroscopic examination during which, in 7 of the patients, the liquid injected under pressure massively escaped into the subcutaneous layer of the medial side of the knee. The patients were divided into 2 groups according to the integrity of the capsule of their knees. Group I consisted of 7 patients, group II of 13 patients. The treatments, the majority of which were conservative, were quite varied, but the post-traumatic functional recuperation was much slower and more variable for the group I patients. These patients presented more significant tissue lesions which certainly contributed to the functional prognosis of the traumatized joint. Seventy two percent of the patients, equally distributed between the 2 groups, presented trochleo-patellar dysplasia. With the exception of age, different clinical parameters (sex, circumstances of the accident, clinical examination) and radiological criteria (external displacement of the patella, detached bony fragment at the interior border of the patella, value of the patellar and trochlear angles, patella alta) did not permit a distinction between the two groups. Because of our results and those in the existing literature we recommend arthroscopy, which is the only examination capable of establishing a complete picture of the lesions and which, in addition, permits rising of the joint and sometimes allows extraction of free osteo-cartilaginous fragments. The younger patients may then benefit from immediate functional reeducation. For older patients, where the tissue lesions are more important, conservative treatment is associated with a slower and sometimes variable functional recuperation. It remains to be determined, whether surgical treatment, adapted to each case, would permit us to obtain better results more rapidly.

Adolescent↗
PubMed1989

[Instability of fractures of the lower end of the radius: apropos of a series of 167 cases].

One-hundred-sixty-seven consecutive cases of distal radius fracture have been treated in our department from October 1985 until November 1987. All cases were rated according to anatomical criteria defined on the first radiogram. These criteria were the presence of a dorsal tilt greater than 20 degrees, dorsal comminution, intra-articular radiocarpal involvement, an associated fracture of the ulna and comminution of the distal radius. Age greater than 60 years was also considered as a factor in determining severity. With regard to fractures treated conservatively (from which comminuted fractures were excluded), a strong correlation was found between the sum of these factors and the risk of secondary displacement. This complication occurs despite a satisfactory initial reduction. Although the surgically treated cases were more severe, significantly better radiological results were observed following surgical management. This mode of classification of distal radius fractures is helpful for determining prognosis and evaluating the risk of secondary displacement and in the course, should help in the selection, perhaps earlier of the most appropriate treatment.

Adolescent↗
PubMed1988

Incidence and prognostic significance of asymptomatic ischaemia in patients with sustained ventricular arrhythmias.

The role of ischaemia in the natural history of sustained monomorphic ventricular tachycardia not related to acute myocardial infarction is not well documented. We examined 38 patients (mean age 60 years, mean ejection fraction 33%) with programmed electric stimulation and thallium scintigraphy to study the presence of perfusion defects and to assess its prognostic significance. Reversible perfusion defects (RPD), alone or in combination, were seen in 17 patients (44.7%), persistent perfusion defects (PPD) in 31 (81.5%), and RPD and PRD combined existed in 14 patients (37%). Normal scintigrams were obtained in only four patients. Segmental analysis gave a mean 'infarction score' (number of PPDs on a total of 15 segments) of 4.2; the mean 'ischaemia' score (number of RPDs) was 1.2. Recurrence of tachycardia or sudden death was observed in 14 patients during a follow-up of 17 +/- 13 months. The predictive value (PV) of the presence of a RPD for recurrence was 63%, the PV of its absence was 82%; the predictive accuracy was 74% (P = 0.0069). This was as important as the data obtained with the drug studies (+PV 83%; -PV 86%; overall PV 83%, P = 0.002). The mean ischaemia score was 3.3 in the group with recurrence and 2 in the patients without recurrence. As pharmacological studies are only feasible in a subgroup with inducible tachycardia, thallium scintigraphy is of benefit to a larger group for predicting effective drug therapy and the risk of recurrence.

Adult↗
PubMed1988

[Treatment of cruciate ligament lesion following knee trauma].

In the treatment of the capsular ligament lesions of the knee joint, the most important therapeutic measure is the reconstruction of the central pillar of the cruciate ligaments. 112 patients with ruptures of the cruciate ligaments and associated injuries have been operated from 1975 through 1985. 78 out of them can be checked-up. Most of the accidents are due to sports or professional activities. 76% of the patients are treated early, i.e. within the first six days from the accident. The rates of simple instabilities as well as of anteromedial rotation instabilities are 40% each, the remaining injuries are severe combined traumas to the knee. In many cases the articular structures are involved, too. The surgical procedure is described. In 89% of the cases, the articular stability is restored with very good or good success by reconstruction. A permanent instability is only observed in two patients. Taking into consideration the mobility and the subjective opinions of patients, 71% have very good or good results.

Adolescent↗
PubMed1986

Postburn serum drug binding and serum protein concentrations.

The free fractions of diazepam, imipramine, lidocaine, meperidine, phenytoin, propranolol, and salicylic acid were determined in the serum of seven burn patients (25% to 80% of their skin surface burned) about one week after the burn and in three of the patients at about four weeks following the injury. Serum protein fractions were measured by electrophoresis, and alpha-1 acid glycoprotein levels were determined. For the drugs that bind predominantly to albumin, the serum free fractions were greater in patients one week after the burn incident than in control subjects (diazepam, 0.055 vs. 0.017; phenytoin, 0.24 vs. 0.16; and salicylic acid, 0.69 vs. 0.32). The increase in free fraction for these drugs was attributed to the postburn decrease in serum albumin levels (2.2 vs. 4.4 g/dL, control). Imipramine, lidocaine, meperidine, and propranolol bind primarily to alpha-1 acid glycoprotein. The free fractions for these drugs decreased one week following the burn (imipramine, 0.074 vs. 0.095; lidocaine, 0.17 vs. 0.35; meperidine, 0.37 vs. 0.48; and propranolol, 0.045 vs. 0.107), presumably in response to the increased alpha-1 acid glycoprotein concentration (222 vs. 83 mg/dL, control). Diazepam, lidocaine, propranolol, and salicylic acid free fractions were still different from control values at four weeks after the accident.

Adult↗