Biomedical subjects

C Stern

Publications and source records attributed to C Stern.

At least 19 recordsLinked to original sources

PubMed1996

Developmental change in spatial grouping activity among children with early focal brain injury: evidence from a modeling task.

Spatial construction skills were assessed in children with left (LH) or right (RH) hemisphere focal brain injury and control children. Children copied simple and complex block models which were rated on accuracy and spatial strategy. The accuracy of simple and complex constructions for 4- to 5-year-old children with LH injury was indistinguishable from 4-year-old controls. However, although they were able to produce accurate complex constructions, the processes used by children with LH injury differed from those of normal children. On both simple and complex constructions, 4- to 5-year-old children with RH injury showed evidence of developmental delay. For both accuracy and process measures, children with RH injury performed at a level comparable to normal children at 3 years. A second group of children with LH and RH injury were tested at 5 to 6 years of age. Both lesion groups were indistinguishable from 4-year-old controls in terms of accuracy. However, both children with LH and RH injury used different spatial processes than did controls. This study emphasizes the importance of distinguishing between products of behavior and the processes which underlie them. It is in the dissociation of products and process of behavior that the subtle spatial construction deficits in this population of brain-injured subjects is revealed.

Brain Injuries↗

PubMed1996

Structural aberrations of chromosome 6 in three uterine smooth muscle tumors.

Clonal karyotypic alterations of chromosome 6 in three uterine smooth muscle tumors are reported. In all cases an apparently identical breakpoint on the short arm of chromosome 6 was found. Two cases displayed the histologic features of cell-rich myomas with severe nuclear atypia but no clear evidence for malignancy. The remaining case was a primary uterine leiomyosarcoma of an 80-year-old patient showing an apparently balanced reciprocal chromosomal translocation, t(1;6)(p32-33;p21.3), as the sole karyotypic abnormality. This type of aberration has not been reported before in leiomyosarcomas. Because of the nuclear atypia in the other myomas with a breakpoint involving the short arm of chromosome 6 we feel that this cytogenetically recognizable but rare subgroup of uterine smooth muscle tumors warrants a careful clinical follow-up.

Adult↗

PubMed1996

Verbal learning and memory in children with fetal alcohol syndrome.

Children with fetal alcohol syndrome (FAS) were administered the California Verbal Learning Test-Children's Version, a word list learning task that assesses immediate and delayed recall and recognition memory. When compared with matched control children, the children with FAS had difficulty learning and recalling the words after a delay period and tended to make an increased number of intrusion and perseverative errors. In addition, they had difficulty discriminating target words from distracter words and made more false-positive errors on recognition testing. Some of these deficits persisted even when mental age was controlled. The results suggest that children with FAS have profound verbal learning and memory deficits, and that some of these deficits cannot be accounted for even when mental age is considered. Furthermore, the results are consistent with deficits in encoding verbal information and impairment in response inhibition capabilities.

Adolescent↗

PubMed1996

[Glaucoma and aircraft pilot fitness].

Two completely different questions arise when considering glaucoma and fitness to fly: Firstly, what is the risk for a passenger with glaucoma? Secondly, what is the flight safety risk connected with pilots suffering from glaucoma? National requirements and international standards pay little regard to this disease. This is astonishing, given that the perception of flight information in the peripheral visual field is of great importance in the cockpit. On one hand, diagnostic glaucoma examinations for pilots are mainly insufficient, and on the other, progressive visual field deficiencies may go undetected because of long intervals between examinations. Intraocular pressure may increase while flying in aircraft, e.g. in the case of negative g-load. Frequent flights at high altitudes without pressurized cabin air and with decreased oxygen supply, and therefore decreased tissue oxygen saturation, may represent a risk, especially for patients with progressive nerve fibre loss.

Aircraft↗

PubMed1995

A hamartoma of the breast with an aberration of 12q mapped to the MAR region by fluorescence in situ hybridization.

Cytogenetic studies of a breast adenolipoma (hamartoma) of a 58-year-old patient revealed a karyotype 46,XX,add(4)(?),add(6)(q?),der(7)t(7;12)(q11.1 or q11.2;q11 or q12),der(12). To our knowledge, this is the second report of an aberration involving 12q12-15 in a hamartoma of the breast. By FISH studies, we found this chromosome 12 translocation breakpoint to be mapping within the MAR (Multiple Aberration Region). MAR is known to be a major cluster region of chromosome 12 breakpoints of benign solid tumors such as uterine leiomyoma, lipoma, and pleomorphic salivary gland adenomas, therefore raising the possibility that the same gene is involved in hamartoma of the breast as in these three benign solid tumors.

Breast Neoplasms↗

PubMed1995

One of the two common mutations causing factor XI deficiency in Ashkenazi Jews (type II) is also prevalent in Iraqi Jews, who represent the ancient gene pool of Jews.

In recent years four mutations causing factor XI deficiency have been identified in Jews of Ashkenazi (European) origin. Two of them, type II (a nonsense mutation) and type III (a missense mutation), were found to prevail among 125 unrelated Ashkenazi Jews with severe factor XI deficiency. A finding of type II mutation in four unrelated Iraqi-Jewish families raised the possibility that this mutation is also common in Iraqi Jews, who represent the ancient gene pool of the Jews. A molecular-based analysis performed in 1,040 consecutively hospitalized patients disclosed the following results: Among 531 Ashkenazi-Jewish patients, the type II allele frequency was 0.0217 and among 509 Iraqi-Jewish patients, 0.0167 (P = .50). The type III allele frequency in the Ashkenazi-Jewish patients was 0.0254, whereas none of 502 Iraqi-Jewish patients examined had this mutation. These data suggest that the type II mutation was present in Jews already 2.5 millenia ago. The data also indicate that the estimated risk for severe factor XI deficiency in Ashkenazi Jews (due to either genotype) is 0.22% and in Iraqi Jews, 0.03%, and that the estimated risk of heterozygosity in Ashkenazi Jews is 9.0% and in Iraqi Jews, 3.3%. As patients with severe factor XI deficiency are prone to bleeding after injury and patients with partial deficiency may have similar bleeding complications when an additional hemostatic derangement is present, the observed high frequencies should be borne in mind when surgery is planned for individuals belonging to these populations.

Aged↗

PubMed1995

Non-random jumping translocations as a result of SV40 large T-antigen expression in benign human tumor cells.

In an attempt to analyse the cytogenetic effects caused by SV40 large T-antigen expression in cells of human benign tumors we transfected cells of an uterine leiomyoma characterized by a primary reciprocal translocation t(12;14) (q15;q24) and a pleomorphic adenoma of the salivary gland with an inversion inv(12) (q15q24.1) using a construct coding for SV40 large and small T-antigen. The most interesting finding was not a generally destabilized karyotype, but the strictly non-random involvement of two chromosomal breakpoints, i.e. 5p13 and 10q11 in jumping translocations, never described before as a result of SV40 transformation. In addition we were able to show by non-radioactive in situ hybridization that there was no direct relationship between the integration site of the construct and the pre-disposition of 5p13 and 10q11 to somatic recombination. The jumping translocations with consistent breakpoints observed closely resemble the cytogenetic situation seen in a variety of human tumors with specific translocations. Based on the findings described here it is tempting to assume that the expression of SV40 large T-antigen can induce specific karyotypic alterations following an unknown trans-acting mechanism.

Adenoma, Pleomorphic↗

PubMed1995

Acute annular outer retinopathy as a variant of acute zonal occult outer retinopathy.

PURPOSE: A 23-year-old man developed a rapid-onset, large, dense scotoma that was associated with a peculiar gray intraretinal ring corresponding to the edge of the scotoma and normal fluorescein angiographic findings. This disorder may represent a variant of acute zonal occult outer retinopathy. METHODS: We studied one patient by ophthalmoscopic examination and fluorescein angiography. RESULTS: The patient experienced a short period of concentric enlargement of the scotoma and narrowing of the retinal vessels within the ring, followed by stabilization of the scotoma and slow progressive depigmentation and intraretinal migration of the retinal pigment epithelium within the zone of visual loss. The cause of this disorder, which affects primarily the outer retina, was not determined. CONCLUSIONS: We speculate that this disorder is part of the spectrum of acute zonal occult outer retinopathy and that the gray border, which separates the normal from the abnormal retina, represents an immune ring phenomenon.

Acute Disease↗

PubMed1995

Paclitaxel plus estramustine in metastatic hormone-refractory prostate cancer.

Combination antimicrotubule therapy with estramustine phosphate (EMP) and vinblastine has reproducible activity in metastatic hormone-refractory prostate cancer (HRPC) with an objective response rate of 31%. Although paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) by 24-hour infusion was inactive in HRPC, 0.5 to 1.0 nmol/L concentrations of paclitaxel combined with EMP exerted synergistic cytotoxicity in DU-145 androgen-independent human prostate cancer cell lines. Based on these results, we treated 24 patients with HRPC using the combination of paclitaxel 120 to 140 mg/m2 by 96-hour intravenous infusion every 3 weeks plus daily oral EMP at 600 mg/m2/d. Of seven patients with measurable soft tissue metastases, three have attained partial responses and a fourth patient is nearing partial response status. Of 16 patients with bone-only disease evaluated by change in serum prostate-specific antigen levels, 11 patients (68.8%) have had decreases of > or = 50% from pretreatment baseline. The prostate-specific antigen decrease has exceeded 80% in six of 16 (37.5%) patients. For all 23 evaluable patients, the prostate-specific antigen has decreased by > or = 50% in 15 (65.2%) and by > or = 80% in eight (34.7%). Grade 4 leukopenia occurred in one of 21 patients treated at the paclitaxel dose of 120 mg/m2/96 hr and one of three patients treated at 140 mg/m2/96 hr. The incidence of nausea (50%) and peripheral edema (37.5%) was similar to that associated with single-agent EMP. These results demonstrate that 96-hour paclitaxel plus EMP is active in HRPC and provide further evidence that the rational combination of antimicrotubule agents leads to synergistic antitumor activity in HRPC.

Adenocarcinoma↗

PubMed1995

Self-tonometry under microgravity conditions.

Microgravity leads to a "fluid shift" towards the upper parts of the body and, therefore, to a rise of the intraocular pressure. Parabolic flights have also demonstrated some rise of the intraocular pressure. During the first German Spacelab mission D1, changes of the intraocular pressure were investigated for the first time in space. The first pressure readings were obtained 44 min after entering microgravity and showed a pressure rise of 20 to 25% compared to the baseline data. To get earlier measurements in microgravity a fully automatic self-tonometer was developed which functioned independent of position and microgravity. It was used during an 8-d manned space mission in March 1992. Measurements of the intraocular pressure have been performed 16 min after reaching microgravity. The pressure readings revealed a 92% rise of the intraocular pressure compared to the daytime-correlated baseline data on Earth.

Fluid Shifts↗

PubMed1994

Kangaroo mother method: randomised controlled trial of an alternative method of care for stabilised low-birthweight infants. Maternidad Isidro Ayora Study Team.

Because resources for care of low-birthweight (LBW) infants in developing countries are scarce, the Kangaroo mother method (KMM) was developed. The infant is kept upright in skin-to-skin contact with the mother's breast. Previous studies reported several benefits with the KMM but interpretation of their findings is limited by small size and design weaknesses. We have done a longitudinal, randomised, controlled trial at the Isidro Ayora Maternity Hospital in Quito, Ecuador. Infants with LBW (< 2000 g) who satisfied out-of-risk criteria of tolerance of food and weight stabilisation were randomly assigned to KMM and control (standard incubator care) groups (n = 128 and 147, respectively). During 6 months of follow-up the KMM group had a significantly lower rate than the control group of serious illness (lower-respiratory-tract disorders, apnoea, aspiration, pneumonia, septicaemia, general infections; 7 [5%] vs 27 [18%], p < 0.002), although differences between the groups in less severe morbidity were not significant. There was no significant difference in growth or in the proportion of women breastfeeding, perhaps because the proportion breastfeeding was high in both groups owing to strong promotion. Mortality was the same in both groups; most deaths occurred during the stabilisation period before randomisation. KMM mothers made more unscheduled clinic visits than control mothers but their infants had fewer re-admissions and so the cost of care was lower with the KMM. Since the eligibility criteria excluded nearly 50% of LBW infants from the study, the KMM is not universally applicable to these infants. The benefits might be greater in populations where breastfeeding is not so common.

Breast Feeding↗

PubMed1994

[Self tonometry during the German 1993 Spacelab D2 mission].

Microgravity during space missions leads to a fluid shift from the lower to the upper parts of the body that also affects the intraocular pressure. In the early phase after reaching microgravity there is an intraocular pressure peak. In order to analyse the potential health risks for astronauts, a self-tonometer was developed to examine the early phase of microgravity. During the German-Russian MIR mission the equipment was tested for the first time in space. As one result we found an initial pressure increase of 92% compared to the baseline data values. In order to obtain more detailed information on the intraocular pressure alterations in space, similar equipment was used during the 10-day German Spacelab D2 mission. Two German scientists and one American astronaut obtained self-tonometric pressure profiles on 6 mission days (44 pressure values determined out of 144 measurements). The initial peak values 15 min after entering microgravity revealed pressure increase of 114% compared to the baseline data (average pressure: right eye 10.0 mmHg, left eye 9.9 mmHg; peak values: right eye 22.6 mmHg, left eye 22.2 mmHg). Pressure values exceeding the baseline data by more than 50% were registered up to the 3rd mission day. As to circadian rhythm, there was no difference between inflight data and baseline data before and after the mission.

Adult↗

PubMed1994

[Evaluation of current guidelines for flying capacity and internationally proposed revisions].

Despite several modifications of medical requirements for German flight personnel, these requirements have often been criticized by ophthalmologists because of their margins of interpretation. In many controversial cases regarding pilot licences, the final decision has to be made by the national aeromedical review board. The progress in ophthalmologic microsurgery, e.g. intraocular lens implantation and refractive surgery, has led to a certain insecurity among surgeons as to how to deal with these developments within the requirements. Besides, new cockpit designs with multiple colour displays have changed the demands on the pilot's visual system, especially with regard to colour perception. New European requirements which will probably become effective in 1994 are compared to the existing German standards.

Aircraft↗

PubMed1994

[Clarity of flight information in the cockpit of the new aircraft generation].

Fundamental changes of cockpit design in recent years, especially the transition from analogue to digital flight information systems and the use of colour-coded displays, lead to new demands on the visual system of the pilot. Twenty experienced pilots each participated in four 15-min sessions with a simulator program in the new Airbus 340 Simulator of the Technical University of Berlin. The pilots were confronted with various flight situations and events. The simulation program was carried out with visual acuity of 1.0 or better, with acuity reduced to 0.5 and with red and green filters. The time between the display of information and the pilot's reaction was determined. The probands were classified into two groups according to their age (< or = 45 years, > or = 45 years). In both age groups a significant difference was found only with green filters. There was no difference with reduced visual acuity or with red filters, and no differences were seen between the two age groups.

Adult↗

PubMed1993

Neuronal responses in the ventral striatum of the behaving macaque.

To analyse the functioning of the ventral striatum, the responses of more than 1,000 single neurons were recorded in a region which included the nucleus accumbens and olfactory tubercle in 5 macaque monkeys. While the monkeys performed visual discrimination and related feeding tasks, the different populations of neurons found included neurons which responded to novel visual stimuli; to reinforcement-related visual stimuli such as (for different neurons) food-related stimuli, aversive stimuli, or faces; to other visual stimuli; in relation to somatosensory stimulation and movement; or to cues which signalled the start of a task. The neurons with responses to reinforcing or novel visual stimuli may reflect the inputs to the ventral striatum from the amygdala and hippocampus, and are consistent with the hypothesis that the ventral striatum provides a route for learned reinforcing and novel visual stimuli to influence behaviour.

Amygdala↗

PubMed1993

Self-tonometry under microgravity conditions.

During a space mission flown in microgravity early changes in intraocular pressure due to the fluid shift effect in microgravity were analyzed with an automatic self-tonometer. In total, 13 pressure readings per eye were obtained during the mission. The first pressure readings 16 min after reaching microgravity revealed a 92% rise in intraocular pressure compared to the daytime-correlated baseline data on earth followed by an adaptation phase lasting for several hours. Diurnal pressure profiles during the mission showed no relevant difference in altitude and amplitude.

Humans↗

PubMed1992

Slowed lexical access in nonfluent aphasia: a case study.

A list priming paradigm (LPP) was used to examine the hypothesis that nonfluent aphasics are literally slowed down in automatic access to lexical information. In this paradigm, words are presented visually, and the subject's task is to make a lexical decision on each word as quickly as possible after its presentation. As soon as a lexical decision is made on one word, that word is removed and, after a predetermined interword interval, the next word is presented. In this way, a continuous "list" effect is obtained. Prior studies with both college-age and elderly subjects using the LPP have shown that, independently of age, on the LPP, priming obtains at interword delays of 500 to 800 msec, but not at either shorter or longer interword delays. In the study reported here, the LPP was used to examine delays at which priming obtained for LD, a nonfluent aphasic with a lesion primarily in the left frontal region. Examining interword delays ranging from 500 to 1800 msec, the subject showed priming only at a delay of 1500 msec, a considerably longer delay than that at which neurologically intact subjects have shown priming. Based on these results, it is argued that while automatic access is retained, that access is much slower in a nonfluent aphasic than in neurologically intact elderly subjects. These results are discussed in terms of how slowed lexical access might impact on discourse comprehension.

Aphasia, Broca↗

PubMed1992

[Cytogenetic subtyping of 139 uterine leiomyoma].

A cytogenetic study of 139 uterine leiomyomas of 70 patients is presented. 26 of the tumours failed to grow, 87 showed an apparently normal karyotype and 26 tumours were characterised by clonal aberrations. In 5 tumours, a numerical change was the only abnormality, including 2 tumours with a trisomy 12. 5 myomas showed an interstitial deletion of the long arm of chromosome 7. The largest group were 9 tumours with an aberration involving chromosome 12 in the band of 14-15. 2 myomas showed a t(12; 14) as the only abnormality, in 4 tumours very complex rearrangements with up to 12 breakpoints were observed. In the last group 7 myomas with other clonal aberrations involving 11 different chromosomes were found.

Animals↗