Educating the next generation of physicians about stroke: incorporating stroke prevention into the medical school curriculum.

BACKGROUND AND PURPOSE: In response to the need to educate physicians about stroke, we have implemented an educational program on stroke prevention for undergraduate medical students within the first-year neuroscience course. This study investigated whether first-year students learned and retained key information about stroke, and used students' feedback both to identify effective curricular components and to explore their attitudes regarding stroke prevention. METHODS: Stroke knowledge and self-assessed confidence in that knowledge before, immediately after, and 8 months after participation in the stroke curriculum were analyzed and compared for 3 classes, using paired t tests and repeated-measures ANOVA. Student feedback about the effectiveness of specific parts of the curriculum and about the importance of stroke prevention was solicited and evaluated. RESULTS: First-year medical students in 3 classes more than doubled their overall stroke knowledge scores (pretest total mean of 8.2; posttest mean 18.0), and retained significant improvement 8 months later (mean 15.7). Subscores in all 4 areas of stroke knowledge tested significantly increased (P<0.001). Students' confidence in their knowledge of stroke risk factors and warning signs, as well as in their knowledge itself, increased (P<0.001). Each of the 3 cohorts demonstrated similar improvements. Feedback indicated heightened awareness and interest in stroke prevention, which was maintained after completion of the curriculum. CONCLUSIONS: These results demonstrate that when instruction on stroke prevention is incorporated into the first-year curriculum, students learn and retain key information. Because entire classes of medical students are involved, this type of approach has the potential to reach all future physicians and therefore to meaningfully impact future stroke care.

Quaking*jimpy double mutant mice: additional evidence for independence of primary deficits in jimpy.

Mice which have the genotype qk/qk*Tajp/Y, and therefore simultaneously express both the quaking (qk) and jimpy (jp) mutations, have CNS white matter morphology intermediate between qk and jp with respect to amount of myelin, myelin structure, and oligodendrocyte number. The level of myelin basic protein in the CNS is also intermediate; however, myelin proteolipid protein (PLP) is virtually absent. Thus in the qk/qk*Tajp/Y double mutant mouse the PLP deficit is as severe as in jp alone but the oligodendrocyte survival deficit (reflected in number and myelin production) of jp alone is rendered less severe. The observation that these two cardinal deficits of the jp mutation can be independently altered in double mutant combinations is consistent with our previous suggestion that the PLP genetic locus may encode at least two independently regulated primary gene functions: a structural protein and signal influencing oligodendrocyte behavior.

Correlation between verapamil plasma concentration and P-R prolongation in essential hypertension.

Plasma verapamil concentration was correlated with serial electrocardiographic P-R intervals in patients with essential hypertension receiving immediate-release (80 to 120 mg three times a day) or sustained-release (240 mg daily) verapamil. The mean P-R interval in 22 patients taking placebo and immediate-release verapamil was 0.18 second. The borderline first-degree atrioventricular block of three patients did not change during treatment. Plasma verapamil concentrations of patients with a P-R interval longer than 0.20 second and of those with a P-R interval of 0.20 second or less were 169 +/- 73 ng/mL and 63 +/- 8 ng/mL, respectively. Six patients taking sustained-release verapamil had a maximal mean P-R interval of 0.19 +/- 0.01 second during 24-hour ambulatory electrocardiographic monitoring. P-R intervals were 0.22 second or more in two patients, but they returned to normal by hour 7 for one and by hour 20 for the other patient. In summary, transient P-R prolongation occurred with oral verapamil therapy, but no patient, regardless of baseline P-R interval, developed high-grade atrioventricular block.

Characterization of the eaeA gene from rabbit enteropathogenic Escherichia coli strain RDEC-1 and comparison to other eaeA genes from bacteria that cause attaching-effacing lesions.

A number of enteric pathogens, including enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli, Hafnia alvei, a strain of Citrobacter freundii, and rabbit EPEC strain RDEC-1 cause attaching-effacing (AE) lesions in the gut mucosa. These bacteria have a pathogenicity cassette (locus of enterocyte effacement or LEE) containing the eaeA gene. This gene encodes intimin, an outer membrane protein required for production of AE lesions. RDEC-1, a non-invasive enteropathogen in young rabbits, produces AE lesions morphologically indistinguishable from lesions caused by human AE bacterial strains. The RDEC-1 example of E. coli diarrhea in rabbits is an important model for studying the pathogenesis of AE bacteria in a natural infection and for analyzing specific roles of the components of LEE. In order to better understand the role of intimin in the development of AE lesions, a portion of DNA within RDEC-1 LEE, containing the eaeA gene and an upstream open reading frame (ORF), was sequenced. The RDEC-1 eaeA gene shared 87%, 92%, and 93% DNA sequence identity and > 80% amino acid sequence identity with the eaeA genes of C. freundii biotype 4280, EHEC O157:H7, and EPEC O127:116, respectively. The carboxy-terminal 280 amino acid residues of intimin has 80%, 56%, and 54% identity with C. freundii, EHEC O157:H7, and EPEC O127:H6 intimins, respectively. The predicted protein encoded by the upstream ORF (156 amino acids) shares 95%, 97%, and 99% amino acid identity with predicted proteins from C. freundii. EHEC O157:H7, and EPEC O127:H6, respectively. The high degree of sequence homology of the ORF and the eueA gene of RDEC-1 with those of other AE bacteria suggests an evolutionary relationship of LEE and supports and facilitates the use of the RDEC-1 model for studying the role of LEE in pathogenesis.

The CS6 colonization factor of human enterotoxigenic Escherichia coli contains two heterologous major subunits.

The genes encoding the CS6 colonization factor were cloned from two human enterotoxigenic Escherichia coli strains of different serotypes. The DNA sequences from both clones were nearly identical and contained four open reading frames. Two of them have homology to genes encoding molecular chaperones and ushers found in many other operons encoding colonization factors. The two remaining open reading frames encode two heterologous major subunit proteins which makes CS6 unique because other colonization factors have only one major subunit. Upstream and downstream of the CS6 operon the DNA sequences of the clones diverged abruptly.

Quaking shiverer double mutant mice: morphological phenotypes support possible dual actions of the shiverer locus.

Mice doubly homozygous for the two different hypomyelination mutations, quaking (qk) and shiverer (shi) or shiverer myelin-deficient (shimld) (abbreviations: qk*shi and qk*shimld), both have much less myelin than either single mutant ancestor, myelin morphology resembling shi or shimld rather than qk, and abundant shi-type oligodendrocytic microprocesses. The qk*shimld double mutant differs from qk*shi only in having small amounts of normal or abnormal major dense line, in keeping with the morphologic difference between the shi and shimld single mutants. By contrast, shi*jp and shimld*jp have clearly different morphological phenotypes; unexpectedly the major dense line is present in the CNS myelin of shi*jp but not shimld*jp. When shi and shimld act alone, their different DNA abnormalities produce similar protein abnormalities. We speculate that the two mutations interact with qk at a different, later step of DNA expression than they interact with jp. In the interaction with qk, the similar proteins produce similar morphologies. In the interaction with jp, the different DNAs are somehow caused to produce protein differences that are reflected in different morphologies. In this study we have observed for the first time a morphological effect of these mutant genes in heterozygous animals. Of particular importance, animals whose genomes combine shi/+ or shimld/+ with qk/qk produce qk-type, compacted myelin but abundant shi-type oligodendrocyte microprocesses. We consider this as evidence that both shi and shimld have two effects: non-production of a normal structural protein, myelin basic protein, and production of an abnormal protein which perturbs the cytogogic function we postulate to be normally exercised by the myelin basic protein gene.

Shiverer jimpy double mutant mice. IV. Five combinations of allelic mutations produce three morphological phenotypes.

Mice which simultaneously express mutant genes at both the shi and jp loci (double mutant mice) have phenotypes much more complex than simple addition of individual mutant characteristics. Morphological study of shi jpmsd, shimld jp, and shi/shimld jp, and comparison with previously studied shi jp and shimld jpmsd, shows that 3 classes of central nervous system (CNS) white matter morphology are produced. (1) shi jp shows suppression of most jp characteristics: it is like shi except for more major dense line, and possibly more myelin, than shi alone. No other combination has as much myelin or any major dense line at all. (2) shi jpmsd has qualitative and quantitative characteristics intermediate between the two single mutants. (3) All combinations studied involving shimld have much less myelin than either single mutant. Qualitatively they express most jp locus features but suppress all shi locus features except abnormalities of myelin compaction. The difference between shi and shimld has more influence on the double mutant morphology than the difference between jp and jpmsd. In the 3-mutant combination, shi/shimld jp, the influence of shimld completely overrides that of shi. These morphological phenotypes resist assignment to any hierarchy of normalcy, and their specific features have no simple explanation in presently known molecular biology of the shi and jp locus mutations. They suggest the possibility of multiple copies and multiple primary functions of the messages at these loci.

Hypomyelinated mutant mice: description of jpmsd and comparison with jp and qk on their present genetic backgrounds.

Hypomyelinated mutant mice are valuable natural animal systems for analysis of CNS myelin development, chemistry and diseases. One mutant, jpmsd, has never received thorough morphological description. We here describe the detailed morphology of jpmsd, compare it with well-studied jp and qk on their present genetic backgrounds, and discuss the genetic histories of all 3 mutants. Region for region, jpmsd has twice as much myelin as jp, but 1/2--1/5 as much as qk. Both jp and jpmsd have scarce oligodendrocytes, rare nodes of Ranvier, clustering of myelin segments, abnormal lipid-filled cells, frequent degenerating cells, and rare distorted myelin profiles. In contrast, qk has abnormally numerous oligodendrocytes, frequent nodes of Ranvier, no obvious myelin clustering, no lipid-filled cells, rare degenerating cells, and frequent abnormal or distorted myelin profiles. jp and jpmsd are quantitatively different, but qualitatively similar. Since its origin, the jpmsd disease has inadvertently been ameliorated by transferring the mutation to a different background. Persistent differences in the remainder of the genome might account for all remaining apparent differences between jp and jpmsd. In contrast, qk is totally dissimilar in morphology and presumably in pathophysiology.

Genotype-specific myelin formation around normal axons in cytosine arabinoside-treated organotypic cultures injected with normal or shiverer optic nerve.

Organotypic cultures of newborn mouse cerebellum, treated with 'antimitotic' drugs to prevent myelination, contain abundant large neurons and axons but no mature oligodendroglia and no myelin. When oligodendroglia, contained in optic nerve fragments from 7-12-day-old normal or shiverer mutant mouse, are added to the cultures, myelin is formed in the vicinity of the optic nerve explant. The phenotype of the added myelin corresponds to the genotype of the optic nerve added, indicating that the added oligodendroglia are making the myelin themselves rather than contributing a diffusible factor which stimulates native cerebellar oligodendroglia or their precursors. This system will be valuable for direct, detailed comparisons of myelin formation by normal and mutant oligodendrocytes.

Hypomyelinated mutant mice. II. Myelination in vitro.

Organotypic cultures of cerebellum from hypomyelinated mutant mice provide a powerful experimental system for studying the cell biology of the mutant diseases. We have examined the extent to which the culture system reproduces the diseases of three well-known mutants, qk, jpmsd, and jp. Quantitation of myelin profiles per sq. mm of section demonstrates that in vitro, as in situ, qk produces the most myelin jpmsd an intermediate amount, and jp the least. Myelin in qk cultures is unique in being invisible by light microscopy of the living culture. Hypomyelination of jp may be more severe in vitro than in situ. Cultures of jpmsd exhibit many of the ultrastructural features of cerebellar abnormalities that occur in situ: degree of hypomyelination, clustering of myelin segments, scarcity of oligodendrocytes, absence of nodes of Ranvier but presence of heminodes, and apparent structural integrity of the myelin sheaths. Correspondence between in vitro and in situ ultrastructure is more difficult to assess for jp, because the available sample of jp myelin in vitro is too small, and for qk, because the abnormalities observed in situ resemble nonspecific abnormalities of normal myelin in vitro.

Shiverer jimpy double mutant mice. II. Morphological evidence supports reciprocal intergenic suppression.

Mice which carry both the shiverer (shi) and the jimpy (jp) mutations have a morphological phenotype with features of each single mutation by itself but in milder form: the number of myelin sheaths is increased relative to jp, the thickness of sheaths and amount of major dense line is increased relative to shi, and the abnormal, lipid-filled cells characteristic of jp are not seen. However, the abnormal bundles of oligodendrocyte microprocesses and errors in the targeting of myelination which characterize shi are not altered by the presence of the jp mutation. This morphological evidence suggests partial reciprocal intergenic suppression in shiverer jimpy double mutant mice and therefore agrees with conclusions based on biochemical data presented by Kerner and Carson (Brain Research, 374 (1986) 45-53).

Shiverer jimpy double mutant mice. III. Comparison of shimld*jpmsd and shi*jp phenotypes demonstrates dissimilar interactions of allelic mutations.

Double mutant mice, which are of the genotype shimld/shimld*jpmsd/Y and therefore express both the shimld and jpmsd mutations, have a CNS myelin protein composition which resembles shimld/shimld alone but not jpmsd/Y alone. The double mutant CNS white matter morphology shows much less myelin and major dense line than either shimld/shimld or jpmsd/Y, but has other features which resemble jpmsd/Y but not shimld/shimld. In contrast, the parallel double mutant shi/shi*jp/Y, which expresses the alleles shi and jp rather than shimld and jpmsd, has already been shown to have biochemical and morphological phenotypes which are consistent with each other, both being intermediate between shi/shi and jp/Y and therefore suggesting partial reciprocal intergenic suppression (Brain Research, 374 (1986) 45-53 and 54-62). To assist in explaining the apparent inconsistencies between the biochemical and morphological phenotypes of the shimld/shimld*jpmsd/Y double mutant and between interactions of allelic mutations at the shi and jp loci, a hypothesis of multiple primary gene functions at these two loci is proposed.

Myelin deficient (shimld) mutant allele: morphological comparison with shiverer (shi) allele on a B6C3 mouse stock.

A new B6C3 stock of shimld mutant mice is compared in terms of behavior and CNS morphology with both a B6C3 shi stock and reports on other shimld animals. Defects of B6C3 shimld myelination seen at postnatal day 21 (P-21) are comparable to those in B6C3 shi with respect to % axons myelinated, sheath thickness, errors in the wrapping and targeting of myelin and abnormal oligodendrocyte shape. The two mutations are similarly expressed in cerebellar organotypic cultures. However, the major dense line (MDL) is present in a few shimld myelin sheaths at P-21 and a few sheaths show myelin basic protein by immunocytochemistry, while neither phenomenon is seen in shi at this age in the same CNS regions. Shimld mice survive their disease significantly better than shi. The shimld stock currently under study elsewhere differs from this B6C3 stock in that MDL was reported only in older animals, and behavior and survival were severely compromised.

Myelination of jp,jpmsd, and qk axons by normal glia in vitro: ultrastructural and autoradiographic evidence.

Normal optic nerve glia were 'injected' into hypomyelinated mutant jp,jpmsd, and qk cerebellum by co-culturing explants in direct physical contact. Quantitative light microscopic studies demonstrated that such glial injection significantly increased the number of myelin profiles counted in cultures, suggesting that axons in all 3 mutants can accept myelination from competent glia when they are made available. In each mutant, the observed increase in myelination was independent of the ages of donor optic nerves and recipient cultures, but absolutely required positioning of the optic nerve so that direct contact occurred with the mutant cerebellar explants. The additional myelin found near the zone of fusion with the optic nerve morphologically resembled normal, not mutant myelin. Autoradiographs made after [3H]thymidine-labeled normal optic nerve was injected into jpmsd cultures showed that labeled cells had colonized the nearby mutant tissue. Labeled cells identified as oligodendrocytes by ultrastructural criteria were found adjacent to myelin segments near the fusion zone, but direct continuity between processes of these oligodendrocytes and myelin sheaths was not demonstrated. The astrocytes and phagocytic cells which were also labeled had no obvious relationship to myelinated axons. These results provide experimental evidence that the primary abnormalities produced by the three mutations jp,jpmsd, and qk are inherent in their glial cells, probably although not definitely in the oligodendrocytes.

Hypomyelinated mutant mice. V. Relationship between jp and jpmsd re-examined on identical genetic backgrounds.

jp and jpmsd, two allelic mutations in the mouse that sharply reduce the amount of CNS myelin, produce diseases that can be distinguished morphologically only by their severity. This has raised the question of whether the two mutations are truly distinguishable. Since the two mutations have never been maintained on the same genetic background, correct quantitative and morphological comparison have not been possible. We have prepared a B6C3H stock of jp on the same genetic background as the available stock of jpmsd. In this jp stock, behavioral abnormalities, relative proportion of myelinated axons, and major morphological characteristics of the disease in situ are unchanged from the previous jp stock. The jp disease continues to be more severe than that of jpmsd. However, tissue from the new B6C3H stock myelinates better in organotypic culture than previous jp stocks. The increase in myelination is advantageous, not only for accurate comparison of the two alleles but for all culture studies of jp. Strictly comparable strains or stocks should be utilized in any comparative studies of closely related mutations such as jp and jpmsd.

Phase II trial of CHIP for the treatment of advanced, hormonally refractory carcinoma of the prostate. A Southwest Oncology Group Study.

CHIP, a second generation analogue of cisplatin, was subjected to a Phase II trial for the treatment of advanced, hormonally refractory carcinoma of the prostate. Forty-six patients were treated with CHIP 300 mg/m2 intravenously every 4 weeks. Evaluations for tumor response were done after three cycles of therapy. Among 40 evaluable patients there were no complete responses, but there were 6 partial responses for an overall response rate of 15% (95% confidence interval of 5.7 to 29.8%). The median time to response was 2.4 months and the median progression-free survival was 4.1 months. Median survival was 8.4 months. The most common toxicities were hematologic and gastrointestinal. While CHIP can be administered on an outpatient basis, its response rate for prostatic carcinoma appears to be similar to that of cisplatin.

Continuous-infusion 5-fluorouracil and cisplatin for advanced/recurrent transitional cell cancer of the bladder: a Southwest Oncology Group trial.

Significant toxicities result from the use of MVAC (methotrexate, vinblastine, adriamycin, cisplatin) for advanced/ recurrent transitional cell carcinoma of the bladder (ARTCCB). An alternative regimen of 5-fluorouracil (5-FU) and cisplatin was evaluated by Southwest Oncology Group (SWOG). Thirty-eight patients with ARTCCB were treated with continuous infusion 5-FU 1,000 mg/m2/days 1-5 and cisplatin 100 mg/day 1, on a every-21-days schedule. There were two complete responses (CR) and eight partial responses (PR) among 36 eligible patients, for an overall response rate of 28% [95% confidence interval (CI) 14-45%]. Median duration of response was 6 months, and median duration of survival was 9 months. No toxic deaths occurred. Grade 4 leukopenia occurred in 5 patients. Other toxicities were mild. Only two documented infections occurred in 5 patients with neutropenia. The response rate of 28% is better than that achieved with cisplatin alone and not dissimilar to the range of response for MVAC. Toxicities were less and tolerable. This regimen will need further evaluation.

Phase II evaluation of ifosfamide/mesna in metastatic prostate cancer. A Southwest Oncology Group study.

The combination of ifosfamide and mesna was evaluated in a phase II trial in the treatment of metastatic prostate cancer. Two separate groups of patients were to be evaluated: patients with no prior hormonal therapy and hormonally refractory patients. Patients were treated with ifosfamide 1.5 g/M2, and mesna at 30% of the ifosfamide dose was administered immediately before and 4 and 8 h after ifosfamide treatment. Both drugs were given i.v. daily for 5 days every 21 days. Response was assessed every 6 weeks. Of 29 eligible and evaluable patients with hormonally refractory disease, there were two partial responders for a response rate of 7% (95% confidence interval, of 0.1-23%). Of nine eligible patients with no prior hormone treatment, there was one partial response, for a response rate of 11% (95% confidence interval, 0.3-48%). Unfortunately, the target accrual goal for this arm of the study was never achieved. The most common toxicities were myelosuppression and neurologic toxicity. These drugs do not warrant further evaluation in the disease.