A nuclear mutant of Chlamydomonas that exhibits increased sensitivity to UV irradiation,reduced recombination of nuclear genes,and altered transmission of chloroplast genes

Summary Meiotic progeny of Chlamydomonas reinhardtii normally receive chloroplast genomes only from the mt ⁺ parent. However, exceptional zygotes, which transmit the chloroplast genomes of both parents or, more rarely, only those of the mt ^- parent, arise at a low frequency. Mutations at the mt ⁺-linked mat-3 locus were found previously to elevate the transmission of chloroplast genomes from the mt-parent, resulting in a much higher than normal frequency of exceptional zygotes. In this paper we demonstrate that an ultraviolet-sensitive nuclear mutation mapping at the uvsE1 locus, which is unlinked to mating type, also promotes chloroplast genome transmission from the mt ^- parent. This mutant, which was previously shown to reduce recombination of nuclear genes in meiosis, acts synergistically which the mat3-3 mutation to produce an extremely high frequency of exceptional zygotes. Through the use of restriction fragment length polymorphisms existing in the chloroplast genomes of C. reinhardtii and the interfertile strain C. smithii, we show that chloroplast DNA fragments from the mt ^- parent normally begin to disappear shortly after zygote formation. However, this process appears to be blocked totally in the absence of wild-type uvsE1 and mat-3 gene products. Our findings are consistent with the hypothesis that both gene products contribute to the mechanism responsible for uniparental inheritance of the chloroplast genome from the mt ⁺ parent.     

Pregnancies after in vitro fertilization and transfer of human blastocysts

In a study of 29 cycles of IVF, ET was performed on day 5 after oocyte recovery when embryos had developed to the morula/blastocyst stage. Three preclinical pregnancies and three live births resulted (2 singleton and 1 twin), giving a viable PR per ET of 10%. It is concluded that while day 5 ET may well be important in terms of embryo biopsy for the preimplantation diagnosis of genetic disease, day 2 ET remains preferable for therapeutic IVF. Although these data would not support the introduction of day 5 ET into routine therapeutic IVF, delayed ET should be considered as an alternative approach to preimplantation diagnosis. Indeed, because the latter will generally involve the treatment of normal, fertile couples, it might be predicted that embryo survival rates, and thus the rate of pregnancy after day 5 ET, would be better than those presented here.     

Neuropsychological efficiency measures in male and female alcoholics.

The role of time in performance on many neuropsychological tests has been relatively neglected in the literature to date. Neuropsychological functioning in 90 male and female alcoholics and 65 peer controls was examined using both accuracy and time measures for four basic types of neuropsychological functioning: verbal skills, learning and memory, problem-solving and abstracting, and perceptual-motor skills. Alcoholics had significantly lower efficiency ratios (accuracy/time) than controls in each of the four areas, and had significantly lower overall accuracy and time scores. There were no significant Group x Gender interactions for efficiency, speed or accuracy scores, indicating that male and female alcoholics have similar deficits as a result of chronic alcoholism. The study is the first to apply systematically an empirical measure of neuropsychological efficiency to different areas of cognitive function; the results have implications for neuropsychological testing procedures.     

Ictal Single-Photon Emission Computed Tomography Imaging in Extra Temporal Lobe Epilepsy Using Statistical Parametric Mapping

PURPOSE: To examine the application of statistical parametric mapping (SPM) to analyze ictal single-photon emission computed tomography (SPECT) scans in surgical candidates with extratemporal lobe epilepsy. METHODS: The authors selected patients who underwent successful ictal SPECT acquisition in the process of surgical treatment of intractable partial epilepsy. Thirteen patients were identified who met inclusion criteria for confident seizure localization from either intracranial electroencephalogram recordings or epilepsy surgery outcome. In these cases, ictal scans were registered to an in-house-developed normal SPECT atlas composed of 14 spatially normalized brains of normal subjects. SPM96 was used to test on a voxel-by-voxel basis for statistically significant increases in blood flow associated with each patient's ictal scan. The results were then mapped back onto the patient's magnetic resonance image (MRI) for final interpretation. Statistical parametric mapping (SPM) analysis of ictal SPECT scans was compared to both conventional visual interpretation and the analysis of subtraction ictal SPECT co-registered to MRI (SISCOM). RESULTS: Ten of 13 patient scans showed localizing focal ictal increases in regional cerebral blood flow, all of which were concordant with ultimate epilepsy localization. Of the 3 cases not localized with SPM, 1 was localized by conventional visual interpretation and another, not localized by visual interpretation, was correctly localized with SISCOM. Two cases not localized by SISCOM were localized by both visual and SPM analysis. CONCLUSIONS: This work provides supportive evidence for proof of principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with extratemporal lobe epilepsy.     

Transplantation using hearts from primary pulmonary hypertensive donors for recipients with a high pulmonary vascular resistance

BACKGROUND: Transplantation for patients with a high pulmonary vascular resistance (PVR) carries an increased risk of mortality and right heart failure following heart transplantation and continues to be a major problem. We evaluated the use of hearts from patients who underwent heart and lung transplantation for primary pulmonary hypertension (PPH) as part of a domino procedure because these hearts have hypertrophied right ventricles used to increased pulmonary pressures, but could have a compromised left ventricle or irreversible damage of the right ventricle. METHODS: We reviewed 12 patients with PVR >4 Wood units who underwent orthotopic heart transplantation between 1989 and 1998 using hearts from donors with PPH as part of a domino procedure. RESULTS: We studied 10 men and 2 women, mean age 42.9 years. Mean PVR was 5.3 (range, 4-9) Wood units. Mean ischemia time was 85.3 minutes, and mean donor age was 32 years. Actuarial survival was 75% at 1 year and 75% at 5 years. In the early post-operative period, 3 patients had temporary arrhythmias, 2 required permanent pacemaker implantation, 1 had atrial fibrillation, and 1 had ventricular tachycardia that required defibrillator implantation. At a mean follow-up of 7.8 years, 2 patients had developed asymptomatic transplant coronary disease (both at 8.5 years after transplantation), 1 moderate and 1 very mild; the rest had none. Mean left ventricular ejection fraction at latest follow-up was 70.1% (range, 63%-78%). Right ventricular function assessed clinically and by echocardiography was adequate in the short and long term. CONCLUSIONS: Our results suggest that heart and lung recipients with PPH can provide useful donor hearts to patients with increased PVR and that these hearts function well in the intermediate and long term.     

Semantic (verbal) and figural memory impairment in alcoholics

In two separate studies, episodic semantic (verbal) and figural-memory abilities as measured by the Wechsler Memory Scale (Russell Method) are compared in middle-aged detoxified male alcoholics and controls. Both studies gave rise to similar findings. Alcoholics recalled significantly less verbal and figural material at both immediate recall and 30-min delayed recall than did the controls. Contrary to expectation, compared to controls, alcoholics did not have a greater differential deficit for the figural material as compared with the verbal or a greater differential deficit on delayed than on immediate memory. The percentage of material recalled at the delayed testing, when taken as a function of the amount of material recalled immediately, did not differ for the two groups on the semantic or figural tasks in either study. Thus, rates of forgetting were equivalent in alcoholics and controls suggesting that the alcoholics' deficit lies in the initial acquisition process. Whether that deficit is in encoding or initial retrieval processes remains to be investigated. Implications for future research are given.