Rapeseed cytoplasm gives advantage in wild relatives and complicates genetically modified crop biocontainment.

Biocontainment methods for genetically modified crops closest to commercial reality (chloroplast transformation, male sterility) would be compromised (in absolute terms) by seed-mediated gene flow leading to chloroplast capture. Even in these circumstances, however, it can be argued that biocontainment still represses transgene movement, with the efficacy depending on the relative frequency of seed- and pollen-mediated gene flow. In this study, we screened for crop-specific chloroplast markers from rapeseed (Brassica napus) amongst sympatric and allopatric populations of wild B. oleracea in natural cliff-top populations and B. rapa in riverside and weedy populations. We found only modest crop chloroplast presence in wild B. oleracea and in weedy B. rapa, but a surprisingly high incidence in sympatric (but not in allopatric) riverside B. rapa populations. Chloroplast inheritance models indicate that elevated crop chloroplast acquisition is best explained if crop cytoplasm confers selective advantage in riverside B. rapa populations. Our results therefore imply that chloroplast transformation may slow transgene recruitment in two settings, but actually accelerate transgene spread in a third. This finding suggests that the appropriateness of chloroplast transformation for biocontainment policy depends on both context and geographical location.

Fitness of hybrids between rapeseed (Brassica napus) and wild Brassica rapa in natural habitats.

Fitness of hybrids between genetically modified (GM) crops and wild relatives influences the likelihood of ecological harm. We measured fitness components in spontaneous (non-GM) rapeseed x Brassica rapa hybrids in natural populations. The F1 hybrids yielded 46.9% seed output of B. rapa, were 16.9% as effective as males on B. rapa and exhibited increased self-pollination. Assuming 100% GM rapeseed cultivation, we conservatively predict < 7000 second-generation transgenic hybrids annually in the United Kingdom (i.e. approximately 20% of F1 hybrids). Conversely, whilst reduced hybrid fitness improves feasibility of bio-containment, stage projection matrices suggests broad scope for some transgenes to offset this effect by enhancing fitness.

Cryopreservation and plant regeneration from somatic embryos of Pinus patula.

Embryogenic tissue of Pinus patula Scheide et Deppe was cryopreserved for 8 weeks using sorbitol and dimethylsulfoxide (DMSO) as cryoprotectants. Results indicate that 0.3 M sorbitol and 5% DMSO had the best cryoprotecting effect. The recovered tissue initially underwent a lag phase but then continued to proliferate normally on MSG3 maintenance medium. Recovered tissue was placed onto MSG5 maturation medium, and embryos were isolated and germinated. Plantlet regeneration from the recovered tissue was achieved.

Exportin 1 (Crm1p) is an essential nuclear export factor.

Nuclear protein export is mediated by nuclear export signals (NESs), but the mechanisms governing this transport process are not well understood. Using a novel protein export assay in S. cerevisiae, we identify CRM1 as an essential mediator of nuclear protein export in yeast. Crm1p shows homology to importin beta-like transport factors and is able to specifically interact with both the NES motif and the Ran GTPase. A mutation in the shuttling protein Crm1p affects not only protein export, but also mRNA export, indicating that these pathways are tightly coupled in S. cerevisiae. The presented data are consistent with the conclusion that Crm1p is a carrier for the NES-mediated protein export pathway. We propose CRM1 be renamed exportin 1 (XPO1).

gamma1 heavy chain transgenes are responsive to IFN-gamma repression and CD40 ligation.

The cis-acting elements that regulate production of germ-line transcripts from Ig heavy chain genes and subsequent switch recombination to those genes are poorly defined. We reported that a 17-kb transgene that includes Igamma1, Sgamma1, and Cgamma1 is regulated for germ-line transcription like the endogenous gamma1 gene. Transcripts from such transgenes are expressed only in B cells treated with both LPS and IL-4, and not in B cells treated with LPS alone or in thymocytes or nonlymphoid tissues. We have now found that transcripts from these transgenes are induced by treatment of transgenic B cells by IL-4 alone. As reported by others, IFN-gamma acts to inhibit the IL-4-mediated induction of germ-line transcripts of the endogenous gamma1 gene. We have found that LPS-plus IL-4-induced germ-line transcription of gamma1 transgenes is likewise inhibited by treatment of B cells with IFN-gamma, so the gamma1 gene must include the cis-acting element(s) that confers this inhibition. It is also known that CD40 ligation induces a modest amount of germ-line transcripts from the endogenous gamma1 gene and synergizes with IL-4 to induce large amounts of germ-line transcripts. The gamma1 transgenes are likewise induced by CD40 ligation, suggesting that the response element(s) for CD40 ligation can be found in the gamma1 gene. The promoter region for the germ-line transcripts and the I exon are likely to include some of these cis-acting elements. A series of transgenic mice with the promoter/Igamma1 region conferred low level, lymphoid-specific, RNA expression to a reporter gene, including significant expression in thymocytes. However, the promoter/Igamma1 transgenes were not regulated like the endogenous gamma1 gene, in that transcription in splenic B cells was not increased by LPS plus IL-4.

The gamma 1 heavy chain gene includes all of the cis-acting elements necessary for expression of properly regulated germ-line transcripts.

The regulation of heavy chain switch recombination and the production of germ-line transcripts are highly correlated. IL-4 induces the production of murine gamma 1 germ-line transcripts, and much, if not all, of the regulation is transcriptional. We have investigated the cis-acting elements involved in the regulation of expression of germ-line transcripts by preparing transgenes with the gamma 1 locus. A construct that includes 5' flanking regions, I gamma 1, S gamma 1, and C gamma 1, is regulated like the endogenous gene. Deletion of either most of S gamma 1 or most of C gamma 1 does not alter the correctly regulated expression of the transgenes. An element common to these three different gamma 1 transgenes confers insertion-site independence and copy-number dependence on the transgenes. Finally, the absolute amount of gamma 1-line transcripts is regulated, as transgenic mice with more than 30 gamma 1 genes express no more germ-line transcripts than nontransgenic mice.

Declining morbidity and mortality of carotid endarterectomy. The Wake Forest University Medical Center experience.

The 30-day mortality as well as morbidity for stroke and myocardial infarction were determined by review of the charts for every carotid endarterectomy (N = 389 operations on 356 patients) performed at Wake Forest University Medical Center from 1979 through 1983 to ascertain whether the 16% morbidity and 6% mortality documented in our previous report of 1978 had changed over time. For endarterectomies performed on asymptomatic patients (n = 155), major morbidity included 2 myocardial infarctions and 1 stroke (1.9%). There were 3 fatalities--2 myocardial infarctions and 1 stroke (1.9%). For the symptomatic group (n = 234), major morbidity was 2.1%, mortality 2.6%. The combined morbidity for asymptomatic and symptomatic carotid stenosis was 2%, mortality 2.3%. Perioperative stroke rate (morbidity plus mortality) was 2.6%, 9 ipsilateral to the carotid endarterectomy, suggesting distal embolism as its probable cause. We contend that quality control measures implemented to correct the unacceptable rates reported in 1978 have contributed to dramatic and sustained reductions in complication rates.

The sex difference in manifestations of carotid bifurcation disease.

One would think that risk factors for transient ischemic attack (TIA) and asymptomatic carotid bruit (ACB) would be similar. In our referral population and in several previously reported cohort populations, however, men outnumber women among patients with TIA. In contrast, women outnumber men among patients with ACB. We found in two independent populations that women with ACB are up to 5.7 times less likely than men to have carotid stenosis. Thus women are more prone than men to have ACB, but their bruits much less commonly reflect carotid stenosis. Women are probably predisposed to have carotid bruit even in the absence of carotid stenosis. In our referral population of ACB, this tendency among women for carotid bruit without stenosis does not seem to be related to lower hematocrit, higher prevalence of heart murmur, constitutionally smaller carotid arteries, or differences in pulse rate or body habitus.

Asymptomatic carotid bruit and stenosis. A prospective follow-up study.

We observed 70 patients with asymptomatic carotid bruits with and without stenoses for cerebral and myocardial ischemic events. Four patients developed transient ischemic attacks (TIAs) without subsequent cerebral infarctions; all of the TIAs occurred distal to vessels with greater than or equal to 50% stenoses. Three cerebral infarctions occurred, but only one was distal to a vessel with stenosis greater than or equal to 50%. Six myocardial infarctions occurred, predominantly in patients with previous myocardial infarctions, congestive heart failure, and left ventricular hypertrophy. Our results confirm previous reports that an asymptomatic carotid stenosis is more often complicated by a TIA than an unheralded cerebral infarction. Cerebral infarctions that do occur are often only marginally related to the carotid bifurcation lesion. In patients with asymptomatic carotid bruit and stenosis, myocardial infarctions occur more frequently and are more commonly the cause of death than cerebral infarctions.

Asymptomatic bruit, carotid and vertebrobasilar transient ischemic attacks--a clinical and ultrasonic correlation.

One hundred patients with asymptomatic carotid bruit or transient ischemic attack (TIA) underwent continuous-wave Doppler (CWD) and real time ultrasound (RTU) testing of their cervical carotid arteries. After ultrasonic studies, 51 patients also underwent bilateral carotid angiography. There was 95% agreement between CWD and angiography for the diagnosis of a significant (greater than 50%) stenosis. The RTU diagnosis of a normal or occluded vessel was correct in 100% of cases. Seven plaques appreciated on RTU may not have been large enough for detection by angiography. In this small series, ulceration confirmed pathologically was more reliably predicted by RTU than by cerebral angiography. Significant ipsilateral carotid plaques occurred more often in patients with amaurosis fugax than in patients with hemispheric TIAs. Ipsilateral plaque ulceration occurred in 50% of symptomatic carotid bruits, but in only 10% of asymptomatic carotid bruits. Plasma concentrations of total cholesterol were significantly higher in TIA patients with carotid stenosis than in controls.

Significance of nonstenotic carotid bifurcation plaques.

It is difficult to determine the significance of nonstenotic carotid bifurcation plaques in patients with ischemic cerebral symptoms. Plaque ulcerations may be associated with platelet/fibrin embolism. Hemorrhages within a plaque may also cause symptoms. In practice, however, plaque ulcerations and intraplaque hemorrhages are difficult to define. The clinical presentation often offers valuable clues to the etiologic significance of nonstenotic carotid bifurcation plaques.

The role of plasma lipids in carotid bifurcation atherosclerosis.

The severity of coronary artery atherosclerosis correlates with increased plasma concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides and with decreased plasma concentrations of high-density lipoprotein cholesterol (HDL-C). The role of plasma lipoproteins in the pathogenesis of cerebral atherosclerosis, however, is less clear. Several investigators report that lipoprotein abnormalities correlate inversely with the incidence of cerebral infarction. We analyzed risk factors for carotid bifurcation atherosclerosis in 121 consecutive patients who underwent cerebral angiography. This analysis revealed a significant positive correlation between the plasma TC/HDL-C ratio and the extent of carotid bifurcation atherosclerosis (p = 0.01). The extent of atherosclerosis correlated inversely with plasma concentrations of HDL-C (p = 0.02). Triglyceride concentration correlated positively with the extent of atherosclerosis with marginal significance (p = 0.07). LDL-C and TC concentrations did not correlate with bifurcation atherosclerosis (p greater than 0.1). Only 4% of the variation in the extent of bifurcation atherosclerosis was explicable on the basis of plasma lipoprotein concentrations.

Wilson's disease: evoked potentials and computed tomography.

Multi-modality evoked potentials and computed cranial tomography (CT) were performed in ten patients with Wilson's disease to determine if any of these studies would correlate reliably with neurologic status. While all four patients with CT abnormality had neurologic signs, two additional patients with neurologic findings had normal scans. Evoked responses were normal in nine patients. The remaining patient displayed abnormal visual, brainstem, and somatosensory evoked potentials, and follow-up studies after clinical deterioration revealed worsening of the brainstem and visual evoked potentials. This patient died unexpectedly from a subdural hematoma, and postmortem examination confirmed the radiographic findings of cortical atrophy of the cerebrum and cerebellum and bilateral cystic degeneration of the basal ganglia. However, localized demyelination in the visual, auditory, and sensory pathways was not present. We conclude that the clinical neurologic status of patients with Wilson's disease cannot be reliably predicted by either CT or multi-modality evoked potentials.

Monocular elevation paresis caused by an ipsilateral lesion.

A 52-year-old woman presented with a paresis of elevation of the right eye, equally severe in abduction and adduction (monocular elevation paresis). CT demonstrated a small, right-sided tumor of the mesodiencephalic junction. Monocular elevation paresis has been attributed to lesions of the contralateral pretectum, although proof has been lacking. Now, with documentation of an ipsilateral brainstem etiology, we can postulate a lesion affecting the upgaze efferents from the ipsilateral rostral interstitial nucleus of the medial longitudinal fasciculus.

Internal ophthalmoplegia resulting from acute orbital phycomycosis.

Phycomycosis is an opportunistic infection occurring in immunocompromised hosts. It is the most acutely fatal fungal disease known. Therefore, early recognition and treatment are essential. Ocular and orbital involvement is part of a rhino-orbital-cerebral form of the disease. The orbital apex syndrome is the hallmark orbital involvement. A case of phycomycosis with internal ophthalmoplegia alone is reported. The internal ophthalmoplegia is probably secondary to involvement at the apex of the orbit, although not sufficiently diffuse to result in the complete orbital apex syndrome.

Acute alcoholic myopathy.

Muscle disease associated with alcohol abuse is more common than is generally realized. The chronic painless form of alcohol myopathy is thought by some to be an atypical neuropathy. Patients with the acute painful variety have pain, swelling, tenderness, cramps and weakness in one or more muscle groups, usually after an alcoholic binge. Clinical differentiation of this form of myopathy from deep vein thrombosis can be challenging. Ethanol and its metabolite, acetaldehyde, have direct pathologic effects on skeletal muscle.

Drusen-associated visual field defects and hemorrhages.

Retinal hemorrhages and visual field defects can occur as complications of optic nerve drusen. The visual defects of optic drusen are of three types: (1) concentric constriction of the field, (2) enlargement of the blind spot, and (3) nerve fiber bundle defects. Retinal hemorrhages also fall into three categories: (1) splinter hemorrhages overlying the disk, (2) vitreous hemorrhages, and (3) subretinal hemorrhages. The unusual disk vasculature associated with drusen is probably responsible for the retinal hemorrhages and may be the primary defect in the pathogenesis of drusen. Altered axoplasmic transport and abnormal axonal calcium metabolism have also been thought to be significant in the pathogenesis of drusen.

Bilateral internuclear ophthalmoplegia in carcinomatous meningitis.

A 53-year-old man with oat cell carcinoma of the lung developed a bilateral internuclear ophthalmoplegia in association with carcinomatous meningitis. While bilateral internuclear ophthalmoplegia has been described in one case of cryptococcal meningitis, this is the first reported case occurring in association with carcinomatous meningitis.

Cerebellar syndrome following neuroleptic induced heat stroke.

We report a patient in whom extreme hyperthermia, rhabdomyolysis, acute renal failure and a residual pancerebellar syndrome occurred while taking a combination of perphenazine and amitriptyline. We postulate that impaired thermoregulation due to psychotropic drugs was responsible for the development of heat stroke and that the cerebellar syndrome resulted directly from the elevated temperature.