Molecular cloning of the cDNA for human erythrocyte beta-spectrin

Overlapping cDNA clones, totaling 3.3 kilobases (kb) in length, which encode over 50% of the human erythrocyte beta-spectrin subunit, were isolated by antibody screening of a lambda gt11 expression library constructed from human fetal liver mRNA. The amino acid sequence of the C-terminus of beta-spectrin was derived. The size of beta-spectrin mRNA in human erythroleukemia cells was found to be 7.5 kb. Erythrocyte beta- spectrin is encoded by a gene located on human chromosome 14, as determined by cDNA hybridization to human X mouse somatic cell hybrids.     

Spastic long-lasting reflexes in the awake rat after sacral spinal cord injury

Following chronic sacral spinal cord transection in rats the affected tail muscles exhibit marked spasticity, with characteristic long-lasting tail spasms evoked by mild stimulation. The purpose of the present paper was to characterize the long-lasting reflex seen in tail muscles in response to electrical stimulation of the tail nerves in the awake spastic rat, including its development with time and relation to spasticity. Before and after sacral spinal transection, surface electrodes were placed on the tail for electrical stimulation of the caudal nerve trunk (mixed nerve) and for recording EMG from segmental tail muscles. In normal and acute spinal rats caudal nerve trunk stimulation evoked little or no EMG reflex. By 2 wk after injury, the same stimulation evoked long-lasting reflexes that were 1) very low threshold, 2) evoked from rest without prior EMG activity, 3) of polysynaptic latency with >6 ms central delay, 4) about 2 s long, and 5) enhanced by repeated stimulation (windup). These reflexes produced powerful whole tail contractions (spasms) and developed gradually over the weeks after the injury (< or =52 wk tested), in close parallel to the development of spasticity. Pure low-threshold cutaneous stimulation, from electrical stimulation of the tip of the tail, also evoked long-lasting spastic reflexes, not seen in acute spinal or normal rats. In acute spinal rats a strong C-fiber stimulation of the tip of the tail (20 x T) could evoke a weak EMG response lasting about 1 s. Interestingly, when this C-fiber stimulation was used as a conditioning stimulation to depolarize the motoneuron pool in acute spinal rats, a subsequent low-threshold stimulation of the caudal nerve trunk evoked a 300-500 ms long reflex, similar to the onset of the long-lasting reflex in chronic spinal rats. A similar conditioned reflex was not seen in normal rats. Thus there is an unusually long low-threshold polysynaptic input to the motoneurons (pEPSP) that is normally inhibited by descending control. This pEPSP is released from inhibition immediately after injury but does not produce a long-lasting reflex because of a lack of motoneuron excitability. With chronic injury the motoneuron excitability is increased markedly, and the pEPSP then triggers sustained motoneuron discharges associated with long-lasting reflexes and muscle spasms.     

Safety and feasibility of using a central venous catheter for rapid contrast injection rates

OBJECTIVE: Our aim was to determine the safety and feasibility of using a central venous catheter for rapid contrast injections during CT. MATERIALS AND METHODS: An in vitro experiment was performed using a 7-French Arrow-Howes multilumen central venous catheter. Each catheter port was tested by varying contrast agent flow rates delivered by a power injector. Contrast media specifications were kept similar to routine clinical practice. The in vivo experiment included 104 cases in which rapid contrast injections, 3.0-5.0 mL/sec, were delivered through a central venous catheter for dynamic CT examinations. Patient monitoring for early complications of contrast extravasation, cardiac arrhythmia, and allergic reactions was performed. Contrast injections were monitored for pressure limitation, automatic flow-rate adjustment, and catheter injury. Chart review was performed for delayed complications of mediastinal hematoma, infection, or catheter malfunction. RESULTS: During the in vitro experiment, all desired flow rates, 3.0-9.9 mL/sec, could be delivered through the central venous catheter with no catheter injury. No immediate or early patient or catheter complications were observed during the in vivo experiment. Follow-up evaluation revealed that 18 blood cultures and one catheter culture were positive for bacterial growth. In a subgroup of 43 patients, five contrast injections were pressure-limited by the power injector, and only one had the flow rate automatically adjusted to 3.6 mL/sec from 4.0 mL/sec. CONCLUSION: Rapid contrast injection rates, at 3.0-5.0 mL/sec, through the Arrow-Howes multilumen central venous catheter are feasible and safe in the clinical setting. However, a strict protocol should be followed to avoid possible serious complications.     

PIC1 Markov Chain Estimation of Life Expectancy of HIV-Infected Patients: Comparison of Two Treatment Alternatives

In RA clinical trials, functional status is increasingly being used as an outcome measure. While it is rather simple to determine the statistical significance of changes, placing the magnitude of these changes into a clinically meaningful context has not been well documented. MIC is "the smallest difference in score, which patients perceive as beneficial and which would mandate, in the absence of troublesome side-effects and excessive cost, a change in the patient's management" [Jaeschke et al. 1989].
OBJECTIVE: To determine the MIC in functional status, as measured by the Modified Health Assessment Questionnaire (MHAQ).
METHODS: Data from 123 patients were obtained from a randomized clinical trial of a new RA therapy. Outcomes were MHAQ and patient global assessment, measured at baseline and after 4 weeks of treatment. Eight scale items of MHAQ were summed to obtain a total score ranging from 0 to 24. MIC was determined based on unit changes in patient globals. The accompanying change in MHAQ was calculated. Similar analysis was conducted with physician global assessment for comparative purposes.
RESULTS: Changes of 1, 2, and 3 points in patient globals were accompanied by changes of 2.11, 4.14, and 8.4 points in MHAQ. Changes in MHAQ corresponding to patient globals were proportionate, but similar results were not obtained for the physician global.
CONCLUSION: Inconsistencies in patient and physician assessments stress the continued need for including both perspectives in assessments of new RA therapies. For the overall MHAQ score, the MIC was approximately 2. These results should increase the ability to interpret results using MHAQ.     

Bilateral latissimus dorsi flaps for the reconstruction of extensive scalp defects

BACKGROUND:

The reconstruction of large scalp defects is occasionally required. Several methods of scalp reconstruction have previously been described. This paper presents the authors’ experience with two patients in whom traditional methods were not sufficient and in whom bilateral latissimus dorsi free flaps were required.

OBJECTIVES:

To evaluate the effectiveness of a new technique in reconstructing extensive scalp defects.

METHODS:

Two case histories are presented. These include the rationale for the choice of reconstruction used as well as a discussion on the technical features of the surgery.

RESULTS:

Reconstruction was effective in both cases. However, one patient died in the early postoperative period from a pulmonary embolus.

CONCLUSIONS:

Bilateral latissimus flaps can be safely and effectively used in closing massive scalp defects in selected cases.