Effects of priming duration on retention over the first 1 1/2 years of life

Exposing individuals to an isolated component (a prime) of a prior event alleviates its forgetting. Two experiments with 120 human infants between 3 and 18 months of age determined the minimum duration of a prime that can reactivate a forgotten memory and how long the reactivated memory persists. Infants learned an operant task, forgot it, were exposed to the prime, and later were tested for renewed retention. In Experiment 1, the minimum duration of an effective prime decreased logarithmically with age, but was always longer than the duration of a mere glance. In Experiment 2, the reactivated memory was forgotten twice as fast after a minimum-duration prime as after a full-length one, irrespective of priming delay and infant age. These data reveal that the minimum effective prime duration psychophysically equates the accessibility of forgotten memories. We conclude that priming is perceptually based with effects that are organized on a ratio (log) scale.     

The influence of abductor lever-arm changes after shoulder arthroplasty

Clinically, pain relief is usually satisfactory after shoulder arthroplasty, but the range of motion can be limited. The changes of the lever-arms of deltoid and supraspinatus muscles are considered to be important factors influencing postoperative active motion. After excluding patients with muscle weakness resulting from a neurologic condition, patients with chronic rotator-cuff tears, patients who did not follow rehabilitation guidelines, and patients with bilateral arthroplasties, 22 arthroplasty cases remained and were evaluated. Compared with the unaffected side, four radiologic parameters were assessed: (A) offset of humeral head, (B) lateralization of humeral head, (C) acromiohumeral interval, and (D) superoinferior migration of humeral head. The differences were measured and statistically analyzed. In summary: (1) The active and passive range of motion of abduction in scapular plane were 89.5° ± 26.1° and 109.7° ± 25.0°. (2) Parameters A, B, and C statistically changed (p < 0.05). (3) B value of the operated side was reduced below zero in six (27.3%). (4) There was a tendency to create medial shifting and inferior subluxation with the arthroplasty. This had a moderate adverse correlation to the active range of motion (correlation coefficient 0.498). (5) Before normalization for bone size, only C as a single parameter had moderate correlation with motion; after normalization, this decreased. (6) If combined parameters were assessed, A + C had a moderate correlation (correlation coefficient 0.435) with motion. (7) If an accurate anatomic relationship cannot be completely restored, A seemed more significant than any other parameters (p = 0.002); namely, shoulders with a smaller offset had a more limited active range of motion in abduction.     

Plasma selenium levels and risk of hepatocellular carcinoma among men with chronic hepatitis virus infection.

Both experimental and epidemiologic studies have linked a low dietary intake of selenium with an increased risk of cancer. The authors examined the association between plasma selenium levels and risk of hepatocellular carcinoma (HCC) among chronic carriers of hepatitis B and/or C virus in a cohort of 7,342 men in Taiwan who were recruited by personal interview and blood draw during 1988-1992. After these men were followed up for an average of 5.3 years, selenium levels in the stored plasma were measured by using hydride atomic absorption spectrometry for 69 incident HCC cases who were positive for hepatitis B surface antigen (HBsAg) and/or antibodies against hepatitis C virus (mostly HBsAg positive) and 139 matched, healthy controls who were HBsAg positive. Mean selenium levels were significantly lower in the HCC cases than in the HBsAg-positive controls (p = 0.01). Adjusted odds ratios of HCC for subjects in increasing quintiles of plasma selenium were 1.00, 0.52, 0.32, 0.19, and 0.62, respectively. The inverse association between plasma selenium levels and HCC was most striking among cigarette smokers and among subjects with low plasma levels of retinol or various carotenoids. There was no clear evidence for an interaction between selenium and alpha-tocopherol in relation to HCC risk.     

The expression of cytokeratin 18 in transitional cell carcinoma comparing with hepatoma

The epithelium in kidneys and urinary bladders contain CK18 as in liver cells. The modulation of cytokeratin 18 during tumor transformation in hepatoma had been previously recognized through a series of biochemical and immunological approaches. A 14 KD hepatoma related molecules was found in the previous studies. We would like to utilize the hepatoma transformation model to study the changes in CK18 in transitional cell carcinoma, using immunoblotting and western blotting techniques. The result is that transitional cell carcinoma retain their CK18 molecule. Furthermore, CK18 related molecules similar to those seen in hepatoma also present in transitional cell carcinoma. The conclusions are transitional cell carcinoma contains CK18 related proteins similar to those seen in hepatoma tissues. We suggest that this element would be responsible for the change during the malignant transformation processes.     

Cost analysis of revision total hip arthroplasty. A 5-year followup study

A stratified, unselected sample of 30 patients who underwent revision total hip arthroplasty between 1990 and 1992 for whom complete clinical and financial data were available was studied. Clinical data included age, gender, diagnosis, length of stay, operative time and blood loss. Financial data included cost of implants, bone graft and accessories, hospital charge, and surgeon reimbursement. Results were compared with the results of an analogous group of 50 patients who underwent revision total hip arthroplasty at the same institution between 1995 and 1997. Cases were classified as simple (involving revision of only acetabular liner and/or femoral head), routine (revision of acetabular and/or femoral components), or complex (major structural graft, antiprotrusio cage, impacted grafting). For patients undergoing routine revision total hip arthroplasty, a dramatic decline of 52% occurred in length of stay during the 5-year span (10.7 days to 5.1 days). The average operative time also declined significantly (238 minutes to 199 minutes) as did the average implant cost ($4349 to $2827). Despite this, the average hospital charge increased 16% ($29,666 to $34,328). There was a significant and dramatic 35% decline in surgeon reimbursement ($3240 to $2178). There was no significant difference in surgeon reimbursement between simple, routine, and complex total hip arthroplasty. Patients who underwent complex procedures had a significantly greater length of stay (7.3 versus 5.1 days) and operative time (297 versus 199 minutes). The hospital charge was dramatically higher for patients undergoing complex procedures ($51,290 versus $34,328) but the surgeon reimbursement was lower on average, although not statistically significant ($1926 versus $2178). There was a significant increase in the number and complexity of revision total hip arthroplasties between the two periods. Significant decreases were achieved in length of stay, operating room time, and implant cost. Benefits from these changes were accrued to the hospital but not the surgeon because hospital costs decreased significantly whereas surgeon reimbursements declined dramatically.     

Functional expression of the bovine herpesvirus 1 alkaline deoxyribonuclease (UL12) inEscherichia coli

Summary Sequence analysis within the unique long segment of the bovine herpesvirus 1 (BHV-1; infectious bovine rhinotracheitis virus) genome identified an open reading frame whose deduced protein product of 487 amino acids exhibited homology to alkaline deoxyribonucleases (DNases) of other herpesviruses. To determine this BHV-1 gene product has nuclease activity, the gene designated UL12 was inserted into the vector pET-28a(+) and expressed inEscherichia coli as an oligohistidine-tagged protein. Upon induction with isopropyl -D-thiogalactopyranosideE. coli BL21 (DE3) [pLysS] cells carrying this recombinant plasmid produced a 57-kDa protein, the molecular mass of which was in accordance with the prediction from the DNA sequence. The recombinant UL12 protein purified by nickel-chelating affinity chromatography exhibited both exonuclease and endonuclease activity, each with an alkaline pH optimum.     

Persisting axonal degeneration in the hippocampus after transection of the fimbria-fornix

Degeneration within the hippocampus was examined at the light microscopic level using the Gallyas silver stain two, four or nine months after bilateral transection of the fimbria-fornix and commissural connections. At two or four months after the lesion the strata oriens and radiatum of the subicular end of the CA1 subfields were strongly argyrophilic as was the inner third of the molecular layer of the dentate gyrus. At nine months post-lesion argyrophilia diminished but clearly persisted in the same layers. Electron microscopic examination revealed a large number of electron-dense axon terminals in the argyrophilic areas, most of them making asymmetric synaptic contacts with dendritic spines. These findings suggest that at least a portion of the Schaffer collaterals of the CA3 pyramidal cells and associational collaterals of hilar neurons were in a process of acute degeneration at all time points after the initial surgical trauma. This persistent synaptic reorganization of intrahippocampal circuits may be related to abnormal electrical activity observed several months after fimbria-fornix transection.     

Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8±15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 Ci of carbon-14 labelled urea. From each patient only one breath sample was collected in hyamine at 10 min. The amount of ¹⁴C collected at 10 min was expressed as follows: [(DPM/mmol CO₂ collected)/(DPM administered)] × 100 × body weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min ¹⁴C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%. Correspondence to: Chia-Hung Kao     

Heterotopic ossification around the hip in spinal cord-injured patients. A long-term follow-up study.

Twenty patients with spinal cord injury complicated by ossification around the hip were followed for eighteen months or more. The bone scan, roentgenogram, level of alkaline phosphatase, and range of hip motion of each patient were analyzed. The average follow-up was forty months. The heterotopic ossification usually did not mature until after one and one-half years. The roentgenograms were of no value in judging its maturity. The bone scan correlated well with the results of the alkaline phosphatase testing in judging maturity of the ossification. We concluded that before operative resection, a patient should have a normal level of alkaline phosphatase, decreasing activity on the bone scans, and a restriction of motion to less than 50 degrees of hip flexion.