Radiology should be a required part of the medical school curriculum

The interests of the future medical community and its patients would be better served if radiology were made a part of the core curriculum in all 4 years in all medical schools so that it would be impossible to obtain an M.D. degree in this country without a thorough grounding in this vital subject. Radiology should no longer be an elective part of the curriculum now that so much of the study and practice of medicine depends on familiarity with imaging studies.     

The obstetric implications of teenage pregnancy

A retrospective review was performed on the obstetric outcome of teenage pregnancies delivered in 1 year in a tertiary centre. The results were compared with the rest of the obstetric population in the same hospital in the same year. The teenage mothers (n = 194) had increased incidence of sexually transmitted diseases (5.2 versus 1.0%, P < 0.05), and preterm labour (13.0 versus 7.0%, P < 0.01), but decreased incidence of gestational glucose intolerance (3.1 versus 11.4%, P < 0.001), when compared with the non-teenage mothers (n = 4914). There was no difference in the types of labour, while the incidence of Caesarean section was lower (4.1 versus 12.6%, P < 0.001) in the teenage mothers. Although the incidence of low birthweight was higher in the teenage mothers (13.5 versus 6.5%, P < 0.001), there was no significant difference in the mean birthweight, gestation at delivery, incidence of total preterm delivery, or perinatal mortality or morbidity. The results indicate that the major risk associated with teenage pregnancies is preterm labour, but the perinatal outcome is favourable. The good results accomplished in our centre could be attributed to the free and readily available prenatal care and the quality of support from the family or welfare agencies that are involved with the care of teenage mothers.      

Die Elimination von α-Acetyldigoxin und k-Strophanthin bei Niereninsuffizienz

Zusammenfassung Radiochemische Untersuchungen beim Menschen über die Elimination von H³--Acetyldigoxin und H³-k-Strophanthin zeigen eine deutliche Ausscheidungsverzögerung in Korrelation zum Grad der Niereninsuffizienz. Besonders bei terminaler Niereninsuffizienz findet sich für die beiden Substanzen ein stark protahierter Abfall der Serumaktivität und eine verminderte kumulative Urinsekretion im Verlauf von 7 Tagen. Die Halbwertszeit für -Acetyldigoxin stieg bei Niereninsuffizienz im Mittel auf 66 Std (normal 24), die für k-Strophanthin auf 60–70 Std (normal 18) an. Die renale Clearance für die untersuchten Glykoside ist eng mit dem Glomerulumfiltrat gekoppelt. In vitro fanden wir eine Dialysance mit der Spulenniere (Twin Coil 145), die ca. 1/5 der Harnstoffdialysance betrug. In vivo können offenbar nur geringe Mengen -Acetyldigoxin und k-Strophanthin mit der Hämo- und Peritonealdialyse eliminiert werden. Daraus ist zu folgern, daß einerseits unter der Dialysetherapie keine zusätzlichen Glykosidgaben erforderlich sind, und daß andererseits eine Digitalisintoxikation nicht wesentlich mit den bisherigen Dialyseverfahren zu beeinflussen ist. Im Gegenteil, durch eine intensive Kaliumsenkung unter der Dialyse können die Glykosidintoxikationszeichen zunehmen. Die radio-chemische Analyse der Digitalispharmakokinetik ergänzt die nach klinischen Kriterien ausgerichtete Glykosidtherapie bei herzinsuffizienten Patienten mit terminaler Niereninsuffizienz.

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Summary Radiochemical investigations on the elimination of³H--Acetyldigoxin and³H-k-Strophanthin demonstrates an accumulation in proportion to the impairment of renal excretion. Especially in terminal renal failure we can find a significant prolongation of serum half time and a reduced cumulative urine excretion (7 days) of these glycosides. The biological half time of -Acetyldigoxin approximatively increased from 24 to 66 hours, the half life values of k-Strophanthin from 18 to 60–70 hours. The renal clearance of the investigated glycosides is narrowly bound to the glomerular filtration rate. The in vitro dialysance (Twin Coil 145) is about one fifth of the urea dialysance. In vivo only little amount of -Acetyldigoxin and k-Strophanthin can be eliminated by hemodialysis or peritoneal dialysis. Therefore no additive doses of digitalis are necessary during dialysis therapy. On the other hand dialysis is not very effective in cases of digitalis intoxication. Hypokalaemia during dialysis can aggravate digitalis intoxication. Radiochemical studies on the pharmacokinetics of cardiac glycosides contributes to an adequate digitalis therapy in uremia (slow digitalization, decreased maintenance dosage), but the effective dosage should be determined by clinical signs of the heart failure and tolerance.

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Mit Unterstützung des Landesamtes für Forschung, Nordrhein-Westfalen.     

Induced abortion is not a cause of subsequent preterm delivery in teenage pregnancies

To examine the possible impact of previous induced abortion on the occurrence of preterm delivery in the subsequent pregnancy in teenage women, a retrospective case-control study was performed on mothers aged 13-19 years who delivered in one tertiary hospital over a 4 year period. Those who had a history of induced abortion prior to the index pregnancy were identified from the records and compared with a control group without previous induced abortion and who were matched for maternal age and parity. Of the 118 cases thus identified, 28 (23.7%) had more than one induced abortions and 18 (15.3%) had one or more induced abortions in the second trimester. There were 10 (8.5%) para 1 cases. No significant differences could be demonstrated between the study and control groups in the maternal demographics, major pregnancy complications, or perinatal outcome, except for the incidence of smokers which was significantly higher (39.0 versus 14.4%, P < 0.02) in the study group. The number of previous induced abortions did not appear to be related to the incidence of preterm labour, which was 10.2 and 8.5% in the study and control groups respectively. Our findings indicate that previous induced abortion is not a significant cause of preterm labour and delivery in teenage pregnancies.      

A comparative study of the cerebrovascular complications of cocaine: alkaloidal versus hydrochloride--a review

Cocaine, especially in its alkaloidal or "crack" form, has been increasingly associated with cerebrovascular disease. Before the crack epidemic, cocaine hydrochloride (HCl) was also implicated as a cause of stroke. However, less is known about the differences in stroke subtypes, age at stroke onset, or presence of underlying structural cerebrovascular disease with different forms of cocaine use. We compared 26 patients (previously reported) from our four institutions plus 16 cases reported in the literature of stroke associated with alkaloidal cocaine to 63 (57 reported in the literature and six not previously reported from our four institutions) cases of stroke associated with cocaine HCl. Ischemic and hemorrhagic strokes are equally likely after alkaloidal cocaine use, whereas cocaine HCl is more likely (approximately 80% of the time) to cause hemorrhagic stroke, with approximately half the intracranial hemorrhages occurring from ruptured cerebral saccular aneurysms or vascular malformations. The presence of an underlying cerebral aneurysm was more common among patients with cocaine HCl-associated strokes than alkaloidal cocaine-associated strokes. Cerebral infarction was significantly more common among the alkaloidal cocaine users than in all the cocaine HCl users, and this was also true when alkaloidal cocaine users were compared with parenteral cocaine HCl (intravenous and intramuscular) users. Only hemorrhagic stroke has been reported with intravenous cocaine HCl use. We conclude that the pathogenesis of cocaine-related stroke is heterogeneous, and depends, in part, on the form of cocaine used.     

Single-photon emission computed tomography in distal field hypoperfusion.

To assess the ability of technetium-99m hexamethylpropyleneamineoxime single-photon emission computed tomography (SPECT) imaging to differentiate distal field hypoperfusion from other stroke mechanisms, 24 patients with acute cerebral ischemia were studied. SPECT scans were read by two physicians according to a preestablished set of criteria for distal field hypoperfusion. SPECT patterns read as "probable" or "definite" for distal field hypoperfusion were found in 42% (10/24); of these, 80% (8/10) had ipsilateral carotid occlusion or high-grade stenosis. Severe carotid stenosis was found in 43% (6/14) with SPECT scans negative for distal field hypoperfusion (Fisher exact test [1-tailed] p = 0.0796). The results suggest that a distal field hypoperfusion pattern on SPECT may identify patients with hemodynamically significant large vessel disease.     

Loss of PIP5KIbeta demonstrates that PIP5KI isoform-specific PIP2 synthesis is required for IP3 formation

The three isoforms of PIP5KI (α, β, and γ) synthesize PI4,5P₂ (PIP₂) by phosphorylating PI4P. Therefore, it is not clear why platelets, like all eukaryotic cells, have more than one isoform. To test the hypothesis that PIP5KI isoforms have nonoverlapping functions, we generated a murine line containing a null mutation of PIP5KIβ and analyzed the effect on platelet signaling. PIP5KIβ-null mice had normal platelet counts. In contrast to platelets lacking PIP5KIα, platelets lacking PIP5KIβ exhibited impaired aggregation accompanied by disaggregation. Although platelets lacking PIP5KIβ had only a moderate deficiency of PIP₂ under basal conditions, they had a striking deficiency in PIP₂ synthesis and IP₃ formation after thrombin stimulation. We have also observed that platelets lacking both PIP5KIα and PIP5KIβ have a complete loss of thrombin-induced IP₃ synthesis even though they still contain PIP5KIγ, the predominant PIP5KI isoform in platelets. These results demonstrate that PIP5KIβ, like PIP5KIα, contributes to the rapid synthesis of a pool of PIP₂ that is required for second-messenger formation, whereas the pool of PIP₂ synthesized by PIP5KIγ does not contribute to this process. Additionally, we found that PIP5KIβ-null platelets failed to form arterial thrombi properly in vivo. Together, these data demonstrate that PIP5KIβ is required for rapid PIP₂ synthesis, second-messenger production, and stable platelet adhesion under shear in vivo. These results also demonstrate that after stimulation of a G protein-coupled receptor, IP₃ is completely derived from a rapidly synthesized discrete pool of PIP₂ synthesized by PIP5KIα and PIP5KIβ.