Time course of muscle atrophy and recovery following a phenol-induced nerve block

Clinically, phenol is used often as a neurolytic agent to treat pain and spasticity. The purpose of this study was to examine the time course of denervation and recovery in several hindlimb muscles following application of a 5% aqueous solution of phenol to the sciatic nerve. Phenol was applied to the sciatic nerve of adult female rats either by intraneural or perineural injection. Axonal degeneration was evident within the sciatic nerve 2 days following phenol application, although variable amounts of damage were observed. By 2 weeks, the soleus and tibialis anterior had atrophied to 63% and 51% of control. Reinnervation of hindlimb muscles occurred between 2 and 4 weeks following the nerve block. Following denervation, the soleus became slower in that all of the fibers expressed the slow myosin heavy chain (MHC). At 5 months, maximum tension of the soleus was 74% of control and the muscle consisted of more fast fibers on average, some of which expressed IIx MHC. These data suggest that 5% phenol causes an injury to the nerve that is more severe than a crush injury, and that reinnervation of denervated muscles may be by motoneurons other than those that originally innervated the muscles. © 1996 John Wiley & Sons, Inc.     

聚对苯乙炔（PPV）及其衍生物的研究进展

评价了ＰＰＶ系列衍生物的电学性质、非线性光学性质及其应用。     

免疫抑制剂SIIA9268A的研究.Ⅰ.发酵、分离及理化性质

在用含ｒａｐａｍｙｃｉｎ结合蛋白基因（ＲＢＰ）的啤酒酵母ＲＳ１８８Ｎ及其变株ＲＳ１８８Ｎ△ｒｂｐ：：：ＬＥＵ筛选免疫抑制剂的过程中，得到活性菌株Ｎｏ．ＳＩＩＡ９２６８（鉴定为吸水链霉菌东湖变种）。应用硅胶柱层析和制备ＴＬＣ等方法从其发酵液中分离出活性化合物ＳＩＡ９２６８Ａ。经理化性质鉴定与ｒａｐａｍｙｃｉｎ同质。     

ADJUSTABLE SUTURES IN STRABISMUS SURGERY: A PERSONAL SERIES OF CASES

A personal series of 77 separate primary adjustable suture procedures performed on 69 patients is analysed. Adjustable suture surgery was performed on patients over ten years of age undergoing rectus muscle surgery, and a few selected younger patients. The ages ranged from 7 to 74 years. A 24-month-old infant who had a two-stage-anaesthesia is included in the series.
Thirty-eight of the 69 patients were reoperations. Of the 77 primary procedures, 48 (62.3%) required postoperative adjustment; 29 (37.7%) were tied down without adjustment.
Sixty-two of the 69 patients (89.8%) achieved a "cure". A further four patients (5.8%) were initially in desired alignment, but deteriorated within the follow-up period. Three of these were successfully reoperated. Of the three primary failures (4.4 %) two were reoperated with one achieving orthophoria.
Apart from alignment failure in the primary procedure, complications were minimal. Current follow-up periods range from one to 24 months.     

Sputum induction as a research tool for the study of human respiratory mucus

The study objectives were to compare in vitro transportability and physical properties of respiratory mucus, obtained invasively by direct collection (DC) right after endotracheal intubation and non-invasively by sputum induction with 3% hypertonic saline solution inhalation (SI) 24 h before the anesthesia. Twenty-two patients with no pulmonary disease scheduled for elective abdominal surgical procedures were studied. The parameters analyzed and the main results are as follows. (1) Transportability by cilia (MCT), SI was higher than DC (0.94+/-0.25 and 0.62+/-0.25; P<0.001). There was a significant correlation between the two methods and DC could be estimated by: DC=0.21+(0.44 SI) (r=0.44; P<0.001). (2) Transportability by cough (CC), SI was higher than DC (68.23+/-32.1 and 33.58+/-19.04 mm; P=0.002). (3) Contact angle (CA), SI was lower than DC (10+/-3 degrees and 22+/-14 degrees ; P=0.025). (4) Rheological properties (no significant difference obtained between SI and DC). These results indicated that SI changes mucus physical properties and transportability in non-expectorators.     

Dynamic Mechanical Conditioning of Collagen-Gel Blood Vessel Constructs Induces Remodeling In Vitro

Dynamic mechanical conditioning is investigated as a means of improving the mechanical properties of tissue-engineered blood vessel constructs composed of living cells embedded in a collagen-gel scaffold. This approach attempts to elicit a unique response from the embedded cells so as to reorganize their surrounding matrix, thus improving the overall mechanical stability of the constructs. Mechanical conditioning, in the form of cyclic strain, was applied to the tubular constructs at a frequency of 1 Hz for 4 and 8 days. The response to conditioning thus evinced involved increased contraction and mechanical strength, as compared to statically cultured controls. Significant increases in ultimate stress and material modulus were seen over an 8 day culture period. Accompanying morphological changes showed increased circumferential orientation in response to the cyclic stimulus. We conclude that dynamic mechanical conditioning during tissue culture leads to an improvement in the properties of tissue-engineered blood vessel constructs in terms of mechanical strength and histological organization. This concept, in conjunction with a proper biochemical environment, could present a better model for engineering vascular constructs. © 2000 Biomedical Engineering Society. PAC00: 8719Rr, 8714Ee, 8718-h, 8768+z     

Response properties of neurons in the visual cortex of the rat

Summary Response properties of neurons in the visual cortex, area 17, of Long Evans pigmented rats were investigated quantitatively with computer-controlled stimuli. Ninety percent of the cells recorded (296/327) were responsive to visual stimulation. The majority (95%, 281/296) responded to moving images and were classified as complex (44%), simple (27%), hypercomplex (13%) and non-oriented (16%) according to criteria previously established for cortical cells in the cat and monkey. The remaining 5% of the neurons responded only to stationary stimuli flashed on-off in their receptive field. Results of this study indicate that neurons of the rat visual cortex have properties similar to those of cells in the striate cortex of more visual mammals.Supported by grant EY02964, the Biological Humanics Foundation and the Bendix Corporation     

Morphology and Thermal Properties of MCPA6/ABS by in situ Polymerization of ε‐Caprolactam

Summary: In this work, blends of monomer casting polyamide 6 (MCPA6) and acrylonitrile‐butadiene‐styrene (ABS) were successfully prepared by in situ polymerization via the application of ε‐caprolactam as a reactive solvent. The morphology and thermal properties of MCPA6/ABS were investigated by means of wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. The domain sizes of the ABS phase in MCPA6/ABS blends were much finer than those in corresponding polyamide 6 (PA6)/ABS blends prepared by simple melt blending. With an increased amount of ABS in MCPA6, the melt enthalpy (ΔH_f), the rate of crystallization (T_c) and the degree of crystallinity (X_c(DSC)) of MCPA6 in MCPA6/ABS blends were all decreased. The degree of supercooling (ΔT_d) showed a contrary trend. However, the melting temperatures of these blends were almost unchanged. All the results could be attributed to in situ polymerization and the hydrolysis reaction of ABS that occurred during the polymerization process. Furthermore, WAXD results showed that only α‐form crystals existed in the MCPA6/ABS blends, despite the ABS content and heat treatment.

SEM micrograph of the fractured surface of an MCPA6/ABS blend with an ABS content of 20 wt.‐% (×10 000).     

Mechanical heart valve prostheses:: identification and evaluation (erratum)

Mechanical heart value prostheses have been in use since the 1950s. Many prostheses have been used for a while and then discontinued. Today, there are a large number and variety of prostheses in use and an even larger variety that are in place in patients. These may be explanted at any time for a number of reasons. It is essential for the practicing pathologist to be able to identify the prosthesis and be aware of some of its reported complications and modes of failure. This article, and a second one on bioprosthetic heart valves, is designed as a ready reference guide to heart valve prostheses, their important identifying features, their common complications, and modes of failure. It should help in the accurate identification of explanted prosthetic valves and more definitive reports. This accuracy of identification as well as tracking of abnormalities noted will, we hope, permit the identification of new failure modes and the recording of causes of failure of new (or even modified) prosthetic heart valves.