Evidence that platelet density depends on the alpha-granule content in platelets

The relation between platelet buoyant density and beta-thromboglobulin (beta-TG), a marker for platelet alpha-granule content, was assessed by three independent approaches. (1) Platelets were separated on iso- osmolar discontinuous Stractan density gradients into five fractions, ranging in density from 1.061 g/ml to 1.091 g/ml (20 degrees C). The beta-TG content (mean +/- SD, n = 17) increased with the platelet density from 27.8 +/- 8.6 micrograms beta-TG/10(9) cells (20% less- dense platelets) up to 65.6 +/- 15.5 micrograms beta-TG/10(9) cells (15% most-dense platelets). (2) Activation of platelets in platelet- rich plasma with thrombin, adenosine diphosphate, collagen, or epinephrine resulted in a decreased density of the platelets. This was only seen when there was simultaneous secretion of beta-TG. (3) The less-dense and the more-dense platelet fractions, after isolation by density gradient centrifugation, were separately treated with thrombin. After complete degranulation, the density distribution of the originally less-dense and more-dense platelets were identical and were much narrower than the density distribution of resting platelets.     

Management of patients with angina pectoris by GPs: a study with standardized (simulated) patients in actual practice

BACKGROUND: Little is known about the management of patients with angina pectoris by GPs. OBJECTIVE: The purpose of this study was to assess how a group of GPs managed a patient with angina pectoris complaints in a real-life practice setting during unbiased consultations with standardized patients. METHODS: GPs were consulted during normal surgery hours by a standardized patient portraying a patient with angina pectoris. The setting was Trondheim, Norway. All 87 GPs in the city of Trondheim (Norway) were informed by letter about a study with standardized patients and invited to take part. They were asked to give consent to be visited during actual surgery hours by standardized patients. The date, number and content of the visits planned were not mentioned. They were not told that the study focused on angina pectoris. For budgetary reasons it was decided to ask 24 physicians to participate. The GPs were consulted during normal surgery hours by a standardized patient portraying a patient with angina pectoris. The patients reported on the consultations using a checklist based on guidelines for management of angina pectoris. Outcome measures were the content and number of actions undertaken from the guidelines. RESULTS: Twenty-eight GPs (32%) agreed to participate. Of these, 24 were selected and visited. One doctor detected the standardized patient. The results showed that the participating physicians met 76% of the guidelines used. However, the GPs ordered 31 different types of laboratory test (mean = 7.9, range = 1-18 per physician). In addition, the 23 consultations resulted in seven referrals (two for chest X-rays, four for an exercise test and one referral to a specialist in cardiology). Twenty-two of the 23 doctors made the correct diagnosis and informed the patient accordingly. CONCLUSIONS: When assessed in an unbiased situation in real practice, GPs performed well against a pre- set standard for management of angina pectoris patients. Much variation was found in the request for laboratory tests. These real-life practice data suggest that there is a need for discussing guidelines for effective ordering of laboratory tests in general practice.      

Coil holder and marker system for MR imaging of the total spine

To improve the efficiency of magnetic resonance imaging of the total spine, the authors developed a coil holder and marker system to accurately localize the level of the spine imaged. The patient's external auditory canal and the alignment light on the imager are lined up with marks on the coil holder. The spine is then imaged in three segments by using a 24-cm field of view. The device has been successful in 20 of the 23 patients in whom it was used. The three failures were due to technical problems.     

Southern blot patterns, frequencies, and junctional diversity of T-cell receptor-delta gene rearrangements in acute lymphoblastic leukemia

Southern blot analysis of T-cell receptor (TCR)-delta gene rearrangements is useful for diagnostic studies on the clonality of lymphoproliferative diseases. We have developed 18 new TCR-delta gene probes by use of the polymerase chain reaction (PCR) techniques. Application of these probes for detailed analysis of the TCR-delta genes in normal control samples, 138 T-cell acute lymphoblastic leukemias (T-ALL), and 91 precursor B-ALL allowed us to determine the TCR-delta gene restriction map for five restriction enzymes, as well as the Southern blot restriction enzyme patterns of all theoretically possible TCR-delta gene rearrangements. Based on this information, it appeared that 97% of all 213 detected TCR-delta gene rearrangements in our series of ALL could be detected by use of the TCRDJ1 probe and that the majority (76%) of the 213 rearrangements could be identified precisely. In T-ALL, we found a strong preference for the complete rearrangements V delta 1-J delta 1 (33%), V delta 2-J delta 1 (10%), and V delta 3-J delta 1 (7%) and the incomplete rearrangement D delta 2- J delta 1 (11%). In precursor B-ALL, the majority of rearrangements consisted of V delta 2-D delta 3 (72%) and D delta 2-D delta 3 (10%). The junctional diversity of these 6 preferential TCR-delta rearrangements was analyzed and showed an extensive junctional insertion (approximately 30 nucleotides) for complete V delta-J delta rearrangements, whereas incomplete rearrangements had correspondingly smaller junctional regions. The detailed TCR-delta gene restriction map and probes presented here, in combination with the Southern blot patterns of TCR-delta gene rearrangements, are important for TCR-delta gene studies in ALL; all TCR-delta gene rearrangements can be detected and the majority can be identified precisely. Identification of rearrangements is a prerequisite for subsequent PCR analysis of TCR- delta gene junctional regions, eg, for detection of minimal residual disease during follow-up of ALL patients.     

Diagnosis of Hirschsprung's disease by punch biopsy of rectum

234 punch biopsy specimens of rectal tissue were taken from 112 children. In 94% of the patients the diagnosis of Hirschsprung's disease was confirmed or refuted by the first biopsy. There were no false-positive or false-negative results. One patient developed a serious complication, a pelvic haematoma.