A network of interacting proteins controls the activity of cyclin-dependent kinase 2 (Cdk2) (refs 1,2) and governs the entry of higher eukaryotic cells into S phase. Analysis of this and other genetic regulatory networks would be facilitated by intracellular reagents that recognize specific targets and inhibit specific network connections. We report here the expression of a combinatorial library of constrained 20-residue peptides displayed by the active-site loop of Escherichia coli thioredoxin, and the use of a two-hybrid system to select those that bind human Cdk2. These peptide aptamers were designed to mimic the recognition function of the complementarity-determining regions of immunoglobulins. The aptamers recognized different epitopes on the Cdk2 surface with equilibrium dissociation constant in the nanomolar range; those tested inhibited Cdk2 activity. Our results show that peptide aptamers bear some analogies with monoclonal antibodies, with the advantages that they are isolated together with their coding genes, that their small size should allow their structures to be solved, and that they are designated to function inside cells.

Amino Acid Sequence↗

PubMed1996

The impact of HLA-A matching on long-term survival of renal allografts.

An important contribution of HLA-A antigen matching in renal transplantation was reported initially, hut later publications showed a minor or absent role. We analyzed the contribution of HLA-A locus matching to graft survival in 17,672 first renal transplants from unrelated, nonliving donors. We show that an independent HLA-A matching effect still exists. Due to its relative weakness and late appearance, large numbers and longer follow-up periods are required. The HLA-A matching effect is a significant factor in first renal allograft survival up to 6 years after transplantation, with an increasing effect over time. This is in contrast to the strong, short-lived, effects of HLA-DR and -B matching, which can only be detected up to 6 months and 2 years after transplantation, respectively. A clear additive beneficial effect of HLA-A matching is shown in the group without B and DR mismatches. Therefore, prospective matching for the HLA-A antigens remains important for renal allograft survival.

Graft Survival↗

PubMed1996

Pretectal projections to the oculomotor complex of the monkey and their role in eye movements.

The nucleus of the optic tract (NOT) is associated with the generation of optokinetic nystagmus (OKN), whereas the olivary pretectal nucleus (ol), which lies embedded in the primate NOT, is believed to be essential for the pupillary light reflex. In this anatomical study of the pretectum, projections from NOT and ol to structures around the oculomotor nucleus were traced in the monkey, to determine which cell groups they innervated. 1. 3[H]-leucine injections were placed into NOT and ol, and labelled terminals were observed just outside the classical oculomotor nucleus (nIII), in the "C-group' and midline cell clusters, both of which contain small motoneurons of the extraocular eye muscles. In addition, there were strong projections to the lateral visceral cell column of the Edinger-Westphal complex (lvc), but not to the Edinger-Westphal nucleus (EW) itself. All of these projections were mainly contralateral. 2. NOT efferents terminated over the ipsilateral medial accessory nucleus of Bechterew (nB), but not over the adjacent nucleus Darkschewitsch. 3. Injections of a retrograde tracer into the oculomotor complex showed that the pretectal afferents described above originated mainly from the dorsomedial part of NOT and from ol. 4. The use of a transsynaptic retrograde tracer, tetanus toxin fragment (BIIb), established the monosynaptic nature of the connection between dorsomedial NOT (contralaterally) and ol (bilaterally), to the small extraocular motoneurons outside classical nIII. The "C-group' motoneurons may play a role in vergence, and lvc in pupillary constriction and depth of focus. Our results imply that NOT and ol participate in the control of some aspects of the near-response, which may be important in the generation of some components of OKN in primates.

Animals↗

PubMed1996

Olmsted syndrome. Case report and identification of a keratin abnormality.

BACKGROUND: Olmsted syndrome is a rare disorder characterized by a mutilating palmoplantar keratoderma and periorificial keratotic plaques. It begins in early childhood and is complicated by the development of painful flexion contractures, constrictions, and autoamputations of the digits. Only 11 cases of Olmsted syndrome have been reported to date. However, no biochemical abnormalities in the skin were reported in any of these cases. OBSERVATIONS: We report the 12th case of Olmsted syndrome. In addition, we describe a keratin abnormality found in a skin specimen obtained from our patient. The specimen showed a suprabasilar staining pattern with AE1, an antibody that shows only basilar staining in normal skin. CONCLUSION: We report the 12th case of Olmsted syndrome, review the literature, and describe a keratin abnormality that was found in our patient's skin specimen.

Child↗

PubMed1996

Modulation of vergence by off-vertical yaw axis rotation in the monkey: normal characteristics and effects of space flight.

Horizontal movements of both eyes were recorded simultaneously using scleral search coils in 2 rhesus monkeys before and after the COSMOS 2229 space-flight of 1992-1993. Another 9 monkeys were tested at comparable time intervals and served as controls. Ocular vergence, defined as the difference in horizontal position between the left and right eyes, was measured during off-vertical yaw axis rotation (OVAR) in darkness. Vergence was modulated sinusoidally as a function of head position with regard to gravity during OVAR. The amplitude of peak-to-peak modulation increased with increments in tilt of the angle of the rotational axis (OVAR tilt angle) that ranged from 15 degrees to 90 degrees. Of the 11 monkeys tested, 1 had no measurable modulation in vergence. In the other 10, the mean amplitude of the peak to peak modulation was 5.5 degrees +/- 1.3 degrees at 90 degrees tilt. Each of these monkeys had maximal vergence when its nose was pointed close to upward (gravity back; mean phase: -0.9 degree +/- 26 degrees). After space flight, the modulation in vergence was reduced by over 50% for the two flight monkeys, but the phase of vergence modulation was not altered. The reduction in vergence modulation was sustained for the 11-day postflight testing period. We conclude that changes in vergence are induced in monkeys by the sinusoidal component of gravity acting along the naso-occipital axis during yaw axis OVAR, and that the modulation of the vergence reflex is significantly less sensitive to linear acceleration after space flight.

Animals↗

PubMed1996

An experimental study of tensile strength of six different suture techniques.

Tests were carried out on the strength of six different suture techniques used to join polyester lace ends, for example, in interscapulo-scapulocostal scapulopexy. The following sutures were used: four 5-cm rows of a continuous suture, four 2.5-cm rows of a continuous suture, two 5-cm rows of a continuous suture, 4 or 8 interrupted sutures, and 4 U-sutures. The laces were tested in tension, and load and elongation recorded. The strongest techniques involved a suture of four 5-cm rows of continuous thread (average maximum load at point of failure 1484 N). This was higher than the maximum load at failure of the point of attachment to the scapula.

Analysis of Variance↗

PubMed1996

Compound osteosynthesis of pathological fractures of the proximal femoral shaft. Experimental studies on the biomechanical effects of additional intramedullary splinting.

The biomechanical stability of two compound osteosynthesis techniques with and without intramedullary splinting were compared in 20 paired cadaver femora. Group A was stabilised using a contoured 12-hole DC plate and polymethylmethacrylate cement. In group B an additional intramedullary semi-diameter osteosynthesis plate was inserted parallel to the outer plate and transfixed with the same screws. The specimens were tested in a universal testing machine using a force applied to the specimen at 45 degrees to the load to provoke the most unfavourable condition, consisting of a bending moment and torsion. Both force and extension were recorded. The compound osteosynthesis with an additional intramedullary plate (group B) reached an average higher load stability. This increase of stability was not significant statistically.

Aged↗

PubMed1996

Abnormal sperm morphology is highly predictive of pregnancy outcome during controlled ovarian hyperstimulation and intrauterine insemination.

PURPOSE: The purpose of this study was to assess the predictive value of a modified form of Kruger's strict criteria for sperm morphology for pregnancy outcomes after intrauterine insemination (IUI) and controlled ovarian hyperstimulation (COH) in the presence of normal sperm concentration and motility. MATERIALS AND METHODS: A retrospective review of 42 couples undergoing COH/IUI was stratified by favorable or unfavorable sperm morphology. End points were pregnancy or failure of treatment as defined by four or more cycles of COH/ IUI without pregnancy. RESULTS: An unfavorable morphology (< 4%) was highly predictive of failure during COH-IUI (94.45%; 17/18). A normal PIF was a sensitive indicator of those patients who became pregnant (93.8%; 15/16) and had a fair specificity for failure to achieve pregnancy after four cycles of treatment (65.4%; 17/26). Couples with a favorable sperm morphology were 28.3 times as likely to achieve a pregnancy within four cycles of treatment as those with unfavorable sperm morphology [95% confidence limits, 3.2 to 250.5; P < 0.001]. CONCLUSIONS: Abnormal strict morphologic assessment is both sensitive and specific for pregnancy outcomes in couples undergoing COH/IUI. Couples with persistently unfavorable sperm morphology should be counseled appropriately and would be better served by more aggressive treatment with in vitro fertilization and embryo transfer.

Adult↗

PubMed1996

Sonographic prediction of shoulder dystocia in infants of diabetic mothers.

OBJECTIVE: To determine if the difference between the abdominal diameter and biparietal diameter (AD-BPD difference), as measured by ultrasound examination, predicts shoulder dystocia in borderline macrosomic infants of diabetic mothers. METHODS: A retrospective study was performed of births occurring from January 1990 through June 1995. Eligibility requirements included diabetic pregnancy, ultrasound examination within 2 weeks of delivery, estimated fetal weight of 3800-4200 g, and vaginal delivery. The mean AD-BPD difference was compared in normal deliveries and those complicated by shoulder dystocia, using the Student t test and by multiple regression analysis. A receiver operating characteristic curve was generated to determine if an AD-BPD cutoff value could be used clinically to predict shoulder dystocia. RESULTS: Thirty-one patients, six with dystocia, were eligible for the study. The mean AD-BPD differences for those with and without shoulder dystocia were 3.1 and 2.6 cm, respectively, a statistically significant difference (P = .05). Comparing the groups with and without shoulder dystocia, no significant differences could be found in mean age, parity, weight, birth weight, or gestational age. Shoulder dystocia occurred in six of 20 patients (30%) in whom the AD-BPD difference was at least 2.6 cm but in none of 11 patients in whom it was less than 2.6 cm, also a statistically significant difference (P = .05). CONCLUSION: The AD-BPD difference was greater in borderline macrosomic fetuses of diabetic mothers who experienced shoulder dystocia than in those who had uncomplicated vaginal deliveries. Applying an AD-BPD cutoff value of 2.6 cm to this population prospectively would have provided excellent sensitivity, specificity, and predictive value in identifying those fetuses at high risk for birth injury.

Adult↗

PubMed1996

Upper urinary tract abnormalities in multiple sclerosis patients with urinary symptoms.

OBJECTIVE: To determine the prevalence of upper urinary tract complications in multiple sclerosis (MS) patients with urinary symptoms, and to determine if an association exists between degree of physical impairment and upper urinary tract complications. DESIGN AND SETTING: A cohort study of MS patients seeking treatment at a freestanding, university-affiliated rehabilitation hospital. PARTICIPANTS: A referred sample of 48 patients with MS, exacerbation-free for 6 months with symptoms of neurogenic bladder dysfunction. For each patient, demographic data, disease characteristics, and urologic history was obtained. Using the Kurtzke Expanded Disability Status Scale (EDSS), participants were divided into a control (EDSS < 7) and study (EDSS >/= 7) group. INTERVENTION: Ultrasound examination of the upper urinary tract. MAIN OUTCOME MEASURE: Significant MS-related abnormalities of the upper respiratory tract. RESULTS: Ten of 48 patients (21%) had significant MS-related upper urinary tract abnormalities, which were evenly distributed between control and study groups. In the more disabled study group, abnormalities were associated with the symptom of urinary hesitancy (p < .05) and form of bladder management (p < .05). CONCLUSIONS: Routine screening for upper urinary tract complications appears indicated in a select group of MS patients with urinary symptoms.

Activities of Daily Living↗

PubMed1996

Aspiration as a guide to sepsis in revision total hip arthroplasty.

One hundred sixty-five patients underwent 171 preoperative aspiration arthrograms to evaluate a painful total hip arthroplasty. Intraoperative cultures and histologic specimens were obtained in all cases. Of the 166 aspirations where fluid was obtained, there were 140 true negative, 5 true positive, 18 false positive, and 3 false negative cultures. Sensitivity of hip aspiration to identify periprosthetic sepsis correctly was 50%; specificity was 88%. Hip aspiration with a 50% sensitivity rate lacks the ability to consistently predict those patients with occult periprosthetic sepsis. The routine use of aspiration in evaluation of a painful total hip is probably not indicated. Selective use in patients with a history of wound healing problems, radiographic changes, and elevated laboratory values should be considered.

Arthrography↗

PubMed1996

Lumbar and thoracic epidural blood injections to treat spontaneous intracranial hypotension.

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Adult↗

PubMed1996

Central mesencephalic reticular formation (cMRF) neurons discharging before and during eye movements.

1. One hundred twenty neurons were recorded in the central mesencephalic reticular formation (cMRF) of four rhesus monkeys, trained to make visually guided and targeted saccadic eye movements. Eye movements were recorded with the head fixed, using electrooculography (EOG) or subconjunctival scleral search coils. Seventy-six percent (92/120) of cells discharged before and during contraversive visually guided or targeted rapid eye movements, and 76% of these (70/92) responded during contraversive spontaneous saccades in the dark. cMRF neurons had large contraversive movement fields and either a high (> 10 spikes/s) or low background level of spontaneous activity in the dark. The optimal movement vectors (i.e., saccades with greatest response) were predominantly horizontal, although many had a vertical component. Cells with optimal movement vectors within +/- 25 degrees of pure vertical were more rostral in the MRF and were excluded from the analysis. 2. A subgroup of cMRF neurons (31 of 92) that discharged before and during visually guided saccades were examined for visual sensitivity. Slightly less than one-half of these cells (42%, 13/31) were visuomotor units, i.e., they responded to visual targets in the absence of eye movement. The other 58% (n = 18) did not discharge during the visual probe trial; they were movement-related cells. 3. Microstimulation (threshold 40-60 microA at 333 Hz) at the sites of many of these cMRF neurons produced contraversive saccadic eye movements at short latency (< 40 ms). The amplitude and direction of the elicited saccades were similar to the optimal movement vector determined from single-unit recording. This suggested that cMRF cells recorded at the same locus of electrical microstimulation participated in the network responsible for the production and control of rapid eye movements. 4. The 92 saccade-related neurons were divided into two groups on the basis of their background discharge rate. Firing rates for both low background (28%, n = 26) and high background (72%, n = 66) cells increased approximately 30 ms before contraversive saccades and reached a peak discharge just before saccade onset. The low background neurons had either no activity or generated a few spikes just before the end of ipsiversive saccades. The steady rate of discharge (> 10 spikes/s) of high background neurons was inhibited from approximately 20 ms before ipsiversive saccades until just before saccade end. 5. Cells were also subdivided on the basis of how their discharge rates fell at the end of saccades. Clipped cells (38%, n = 35) had activity that fell sharply with saccade offset. Partially clipped cells (62%, n = 57) had persistent firing in the 100 ms following the saccade that was > 20% higher than the firing during the 100 ms before the saccade. 6. Latencies between the 90% point on the rising edge of the peak discharge and the start of the saccade were < or = 5.3 ms for eye movement-related cells in two monkeys. Longer latencies (11-19 ms) were found when measured between the 10% point on the rising edge of the peak discharge and saccade onset. These latencies were equal to or shorter than those obtained for eye movement-related burst neurons in the intermediate and deep layers of the superior colliculus analyzed similarly. Delays between the peak discharge and peak eye velocity were 13.6-15.1 ms for the same group of cMRF eye movement-related cells. These were significantly shorter than the delays measured for eye movement neurons in the superior colliculus (SC) of one of the monkeys. These findings suggest that the buildup discharge of cMRF neurons occurs early enough before saccades to contribute to saccade triggering. The peak discharge, however, occurs with or after the burst in the SC, suggesting that this portion of the discharge serves a function other than saccade triggering. 7. The number of spikes in bursts associated with eye movement was correlated with saccade parameters.

Animals↗