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Biomedical subjects

J Stam

Publications and source records attributed to J Stam.

At least 73 records · Page 4Linked to original sources
PubMed1990

Pharmacokinetic studies in animals of a new parenteral penem CP-65,207 and its oral prodrug ester.

The pharmacokinetics of penem CP-65,207 diastereomeric mixture were studied following parenteral administration in mice, rats, beagle dogs and cynomolgus monkeys. As is characteristic for most penems, the serum elimination T1/2 of CP-65,207 in rodents was only 13 minutes for mice and 18 minutes for rats. A linear relationship was observed between dose and Cmax following subcutaneous injection of drug in mice. The T1/2 in the beagle dog and monkey following intravenous injection was approximately 23 minutes. CP-65,207 demonstrated binding to human serum proteins of only 10%. In vitro studies using purified porcine renal dehydropeptidase-I (RDHP) indicated that the pure S-isomer of CP-65,207 was 7-fold more stable to inactivation than imipenem. Urinary recovery of CP-65,207 in the dog was 42% compared to 1% for imipenem without RDHP inhibitor. Unlike results obtained with imipenem, coadministration of probenecid with CP-65,207 in the dog doubled the elimination T1/2 and AUC of the penem demonstrating its relative stability in vivo in the absence of a RDHP inhibitor. The pivaloyloxymethyl esters of each pure isomer of CP-65,207 showed significantly different degrees of oral absorption in rats.

Absorption↗
PubMed1989

[Complications and results of diagnostic procedures in the vena cava superior syndrome].

Diagnostic procedures in the presence of superior vena cava obstruction have been reported to be dangerous. We reviewed our experience in 58 patients who presented with this obstruction during the period 1976-1985, to establish the nature and frequency of complications. In 56 of 58 patients we could obtain a diagnosis before instituting therapy. The only complication was one case of peroperative haemorrhage.

Biopsy↗
PubMed1989

Tendon reflex asymmetry by voluntary mental effort in healthy subjects.

The effect of voluntary mental influences on the tendon reflexes was examined in healthy subjects. The patellar reflexes were evoked by a method comparable with the clinical examination, and the reflexes were recorded by surface electrodes. Eighteen subjects were instructed to increase and then decrease the right patellar reflex by mental effort, without contracting any muscles. Most subjects increased the reflex in both conditions. Subsequently, ten subjects were instructed to increase the right patellar reflex and decrease the left by mental effort. Measurement showed reflex asymmetry in seven subjects consistent with the instruction. The experiment was repeated in another 20 subjects with symmetric reflexes at rest. Ten of these subjects were, after random assignment, instructed to increase either the right or the left knee jerk. All subjects (and an additional 15 asymmetric control subjects) were examined by a neurologist without knowledge of the instruction. Three of the ten instructed subjects were correctly judged to be asymmetric, but the agreement between instruction and neurologic judgment was not statistically significant. Mentally induced reflex asymmetry is possible, and may be clinically relevant in some cases.

Adult↗
PubMed1989

Measurement of tendon reflexes by surface electromyography in normal subjects.

A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes in the biceps, triceps, quadriceps and triceps surae were examined in 40 healthy subjects. A characteristic relation between stimulus strength and response amplitude was found which could be described by an empirical function. Latencies of both arm and leg reflexes were linearly related to the height of the subjects. Variations of reflex amplitudes within and between subjects were comparable with previous results obtained with more complicated techniques. Although repeatability of measurement of the amplitude is limited by the variability of reflexes, significant agreement was found between repeated measurements. Most reflex amplitudes were diminished during repeated examination after a short interval. Both measurement and clinical examination showed the frequent occurrence of left-right asymmetry of reflex amplitudes. These left-right differences were reproducible to a significant degree on repeated measurements after more than 2 years.

Adult↗
PubMed1989

Surgical treatment of bronchopulmonary carcinoid tumours.

Based on histopathological characteristics bronchopulmonary carcinoid tumours can be divided into a typical and an atypical variant. Atypical carcinoid tumours often have regional lymph node metastases. A differentiation between the two types of tumours cannot be made preoperatively. A total of 23 patients underwent resectional therapy for carcinoid tumours of the lung. Eleven underwent pneumonectomy, eight patients lobectomy and three patients had bilobectomy. Segmental resection was performed in one patient. One patient died in the postoperative period. During the follow-up period, ranging from 5 to 22 years (median 11 years), neither local recurrences nor metastatic spread was observed. In eight patients the tumour was classified as the atypical variant. There was no correlation between the size of the tumour and the presence of regional lymph node metastases. All tumours with lymph node metastases were classified as atypical carcinoids. As in other studies, our data suggest that treatment based on standard resectional procedures is to be preferred for bronchopulmonary carcinoids since a preoperative distinction between the typical and atypical variants is as yet not possible.

Adult↗
PubMed1988

The tibialis anterior reflex in healthy subjects and in L5 radicular compression.

Phasic stretch reflexes were evoked in the tibialis anterior (TA) muscle, by tapping the dorsal side of the foot with a hand-held reflex hammer. The responses were recorded by means of surface electrodes. The TA reflex was examined in 70 healthy subjects and in 18 patients with L5 radicular compression. In 58 (83%) of the healthy subjects the reflex could be recorded bilaterally, in eight (11%) subjects no reflex was found on either side, and in four (6%) it was absent in one leg. Simultaneous recordings from the gastrocnemius-soleus showed that TA responses were not caused by volume conduction from that muscle. In the 18 patients with L5 radicular compression the TA reflex was absent on the affected side 13 times (72%) and present bilaterally in the other five cases. If asymmetry of the reflex (unilateral absence) is considered as a test for the presence of L5 radicular compression, the likelihood ratio for a positive test is 12.0, and for a negative test 0.3. The examination of the TA reflex is easily performed and can be useful in the diagnosis of L5 radicular compression.

Humans↗
PubMed1988

Combined radiation therapy and daily low-dose cisplatin for inoperable, locally advanced non-small cell lung cancer: results of a phase II trial.

The Free University Hospital in Amsterdam conducted a phase II trial on inoperable patients with non-small cell lung cancer (NSCLC) to evaluate the role of cisplatin as a radiosensitizer. Forty patients were entered into the study. Thirty-three patients were evaluable for response and 37 for toxicity. The regimen consisted of the daily administration of cisplatin 6 mg/m2 administered within 30 minutes after each radiation therapy session. The radiation therapy modality was a regimen of 300 cGy four times per week for 4 weeks with a 2-week split in between, administering a total dose of 48 Gy. The overall response rate was 65%; median duration of control of local disease was 7 months, and overall survival was 10.5 months. Toxicity was considered to be mild. The results appear similar to data using radiation therapy alone; however, the optimum dosing and timing of this combination therapy has not been determined and deserves further clinical studies.

Carcinoma, Non-Small-Cell Lung↗
PubMed1988

Solitary hamartoma of the lung: is thoracotomy still mandatory?

Solitary pulmonary hamartomas are the most common benign tumors of the lung, and have to be distinguished from primary or secondary malignant pulmonary lesions. The data of 20 patients operated for a solitary hamartoma of the lung are presented with special attention to the diagnostic methods which can contribute to the diagnosis. To avoid a surgical procedure, CT-densitometry and fine-needle aspiration biopsy have become of major interest for the diagnosis of hamartoma. Using in succession chest X-rays, CT-densitometry and fine-needle aspiration biopsy, a conservative approach can be advised in specific cases. However, exploratory thoracotomy is mandatory when a patient presents with a solitary pulmonary lesion of more than 2.5 cm or when the lesion shows a tendency to grow.

Adolescent↗
PubMed1988

Laryngeal cancer and lung cancer in the same patient: a retrospective study.

Fifty-four patients with laryngeal cancer and lung cancer were analyzed with regard to histology and localization of the lung cancer, the time interval between the detection of the two tumours and survival. It appeared that most lung tumours were squamous cell carcinomas, half of which were centrally localized and most occurred metachronously in the first 4 years after the laryngeal carcinoma. The survival rate was poor, due to the fact that the bronchial carcinoma usually was found beyond a curative stage. It appears that the present follow-up in laryngeal cancer patients--frequent ENT-examination, yearly chest X-ray examination--is often inadequate for early detection of lung cancer and curative treatment. It might be that by intensifying follow-up in laryngeal cancer patients by bronchoscopy, sputum cytology and more frequent chest X-ray examination, more bronchial carcinomas would be detected in a curative stage.

Aged↗
PubMed1987

Tendon reflex variability and method of stimulation.

Human tendon reflexes show large fluctuations, even when accurate mechanical instruments are used for stimulation. To examine the contribution of stimulus factors to reflex variability two methods of stimulation were compared in healthy subjects. One method consisted of a normal hand-held reflex hammer, with a transducer to measure stimulus intensity. The results with this hammer, both after maximal stimuli and after stimuli over a wide range of intensities, showed a similar variability of reflexes as with a more accurate instrumental stimulator. In previous studies in human subjects an equal or larger variability of reflexes was found. It is concluded that for many applications a simple hand-held reflex hammer gives equally reliable results as more complicated instrumental stimulators.

Adult↗
PubMed1987

Adenosine deaminase activity in tuberculous pleural effusions: a diagnostic test.

The activity of adenosine deaminase (ADA) was investigated in pleural effusions from 10 patients with tuberculous pleurisy and 76 patients with pleural effusions of other aetiology. The ADA activity in the tuberculous patients was significantly higher than in the other groups, with the exception of those with empyema. Specificity (87%) and sensitivity (100%) of this test for tuberculosis is high when a reference limit of more than 53 U/l is taken.

Adenosine Deaminase↗
PubMed1987

Unchanged pharmacokinetics of VP-16-213 (etoposide, NSC 141540) during concomitant administration of doxorubicin and cyclophosphamide.

In patients with small-cell lung cancer VP-16-213 is often given in combination with doxorubicin and cyclophosphamide. Little is known about possible interactions between these drugs. Therefore we investigated in 7 patients the pharmacokinetics of VP-16-213, with and without the other two drugs. We found no change in the pharmacokinetics. We also provide evidence that the pharmacokinetics did not change in two sequential administrations of the drug. Pharmacokinetic data are in agreement with previous reports.

Aged↗
PubMed1987

Phase II trial of combined radiotherapy and daily low-dose cisplatin for inoperable, locally advanced non-small cell lung cancer (NSCLC).

With the use of cis-diamminedichloroplatinum(II), cisplatin, to enhance the effect of radiation a combined modality approach was designed to treat patients with inoperable, locally advanced NSCLC. The regimen consisted of radiation doses of 300 cGy for 4 days every week for 4 weeks with a 2 week split in between. Each radiation dose was followed by an i.v. injection of cisplatin 6 mg/m2 within 30 min. Hydration consisted on an oral fluid intake of 2 L only, enabling the patient to receive the treatment on an outpatient basis. Of 40 patients entered into the study, 37 were evaluable for toxicity and 33 for response. Overall response rate was 65% and complete response rate 22%. Median duration of local control was 7 months. The majority of all patients (76%) eventually progressed at the primary tumor site, while in 16 patients relapse occurred in distant sites first. Median duration of overall survival was 10.5 months, whereas that of complete responders was 29.5 months. Generally, acute side effects were transient and did not require discontinuation of treatment. One patient presented with thrombocytopenia 4 weeks after treatment had been finished. His death of cerebral bleeding was likely to be related with his therapy-resistant malignancy. Of late side effects three patients showed disabling symptoms consisting of uncontrollable pulmonary infections in the presence of tumor in two patients, one patient had radiation myelopathy and another experienced vertebral collapse with distal paresis. The combination of radiation and daily low-dose cisplatin is a tolerable treatment modality with most benefit for patients reaching a complete remission. Intensification of the regimen is being planned in those patients with inoperable, locally advanced squamous cell lung cancer to reach a complete remission.

Adenocarcinoma↗
PubMed1987

Accuracy of diagnostic procedures in the initial evaluation and follow-up of mesothelioma patients.

The present study contains the review of 30 patients with malignant mesothelioma of the pleura, examined and treated at our institution. In an attempt to compare various methods of diagnosis in this entity, emphasis was laid on specific abilities and limitation of investigations such as pleural biopsy, pleural fluid cytology, diagnostic thoracoscopy and thoracotomy and radiological studies including computed tomography and magnetic resonance imaging. Clinical management problems encountered in this neoplasm are also discussed.

Asbestos↗