Extracoelomic approach to the spine

A modified transthoracic approach to the thoracic vertebral column is described. In this method, the parietal pleura is detached from the chest wall and retracted with the visceral pleura and its contents. A direct approach to the vertebral bodies is thus achieved without transgression of the intrapleural space. The technique can be extended to include exposure of the thoracolumbar spinal column, utilising a thoracoabdominal approach with extrapleural and extraperitoneal dissection. Management of the costophrenic detachment is thus simplified. This approach has significant advantages for orthopaedic, vascular and neurosurgical procedures.

Red cell collection by apheresis technology

To determine the feasibility of collecting 2 units (450 mL) of red cells per donation by apheresis technology, apheresis red cell collections were compared to whole-blood donations. Forty blood donors were equally divided between the two study arms on the basis of gender and iron supplementation (650 mg ferrous gluconate/day vs. no supplementation). During the 1-year study period, the apheresis participants donated 450 mL of red cells three times, and the whole-blood donors gave 225 mL of red cells (1 unit of blood) on six occasions. There were no reported side effects during the 102 whole-blood donations, whereas symptoms were noted in 83 percent of the 59 apheresis procedures. The most common symptoms were numbness and tingling, which were relieved by a decrease in the plasma-return rate or by the administration of oral calcium supplements. Seven donors dropped out or were deferred during the study. Two whole-blood donors left with medical problems unrelated to the study, one apheresis donor and one whole-blood donor dropped out of the study because of excessive fatigue, and three non-iron-supplemented whole-blood donors had unacceptably low hematocrit levels. By the end of the study, 70 percent of the apheresis donors considered the procedure acceptable, 15 percent were undecided, and 15 percent thought it was not acceptable. As measures of iron balance, the serum ferritin and the red cell zinc protoporphyrin:heme ratios were significantly more abnormal in the non-iron-supplemented donors than in the iron-supplemented donors. However, there were no differences in iron balance according to the donation method.

GenBank

The GenBank sequence database has undergone an expansion in data coverage, annotation content and the development of new services for the scientific community. In addition to nucleotide sequences, data from the major protein sequence and structural databases, and from U.S. and European patents is now included in an integrated system. MEDLINE abstracts from published articles describing the sequences provide an important new source of biological annotation for sequence entries. In addition to the continued support of existing services, new CD-ROM and network-based systems have been implemented for literature retrieval and sequence similarity searching. Major releases of GenBank are now more frequent and the data are distributed in several new forms for both end users and software developers.

Patient experiences with multiband full dynamic range compression

This investigation compared performance for 18 experienced hearing aid patients with a multiband full dynamic range compression hearing device and their previously worn linear or automatic gain control hearing aids. Performance was evaluated using a variety of clinical tests. These included functional gain and dynamic range measurements, speech recognition, and real ear measurements. Patients rated their performance with the multiband compression device and their previously worn aids on a rating scale pertaining to a variety of real life listening situations. Statistical analysis of data derived from test results shows significantly improved performance on all measures using the multiband compression aid over their conventional aids. Patients rated their performance higher with the compression instrument than with the conventional aids. Differences in performance on clinical tests and subjective patient responses appear to be related to the different signal processing schemes used in the two groups of devices.

Biomedical equipment information management for the next generation

Recent restructuring of the quality assurance standards of the JCAHO and the benefits to be gained from assurance indicators are requiring clinical engineering support groups to manage their equipment inventories with greater precision. Technological enhancements in the database industry have provided these groups with a mechanism with which they can manage. Assessments of equipment reliability, departmental management, and quality assurance give supervisory staff an important tool for feedback.

A comparison of parallel versus perpendicular placement of retention sutures in abdominal wound closure

A new technique for placement of retention sutures is described. Twenty-five rats underwent midline laparotomy incision. The control group was closed with traditional placement of through-and-through retention sutures placed in a perpendicular direction to the wound. The experimental group was closed with retention sutures placed in a parallel direction to the wound as described below. Wound bursting strength was significantly (P less than 0.001) greater at one to five days in the experimental group compared with the control animals. In addition, inflammatory reaction and pressure necrosis were greater in the control group. It appears that parallel placement of sutures has less of a tendency to cut through tissue when subjected to the distracting forces on a midline wound.

Regulation of total and myofibrillar protein breakdown in rat extensor digitorum longus and soleus muscle incubated flaccid or at resting length

The present study characterized total and myofibrillar protein breakdown rates in a muscle preparation frequently used in vitro, i.e. incubated extensor digitorum longus (EDL) and soleus (SOL) muscles of young rats. Total and myofibrillar protein breakdown rates were assessed by determining net production by the incubated muscles of tyrosine and 3-methylhistidine (3-MH) respectively. Both amino acids were determined by h.p.l.c. Both total and myofibrillar protein breakdown rates were higher in SOL than in EDL muscles and were decreased by incubating the muscles maintained at resting length, rather than flaccid. After fasting for 72 h, total protein breakdown (i.e. tyrosine release) was increased by 73% and 138% in EDL muscles incubated flaccid and at resting length respectively. Net production of tyrosine by SOL muscle was not significantly altered by fasting. In contrast, myofibrillar protein degradation (i.e. 3-MH release) was markedly increased by fasting in both muscles. When tissue was incubated in the presence of 1 munit of insulin/ml, total protein breakdown rate was inhibited by 17-20%, and the response to the hormone was similar in muscles incubated flaccid or at resting length. In contrast, myofibrillar protein breakdown rate was not altered by insulin in any of the muscle preparations. The results support the concepts of individual regulation of myofibrillar and non-myofibrillar proteins and of different effects of various conditions on protein breakdown in different types of skeletal muscle. Thus determination of both tyrosine and 3-MH production in red and white muscle is important for a more complete understanding of protein regulation in skeletal muscle.

Effects of bone marrow transplantation and polyinosinic-polycytidylic acid (poly I:C) on the rescue of animals from busulfan-induced NK suppression

Repeated injections of busulfan (Bu) in CAF1 mice caused a long-lasting (greater than 16 weeks) decrease in their natural killer (NK) cell activity and impaired their resistance to transplantable lymphoma. Bu-treated mice had fewer spleen cells capable of binding to NK-sensitive YAC-1 target cells and reduced lymphokine-activated killer (LAK) cell activity as compared to normal age-matched controls. In contrast, interleukin 1 (IL-1) and interleukin 2 (IL-2) production were normal. Transplantation of normal bone marrow cells into Bu-treated mice resulted in an elevation of IL-2 production as well as in complete restoration of NK activity, target cell binding, and partial restoration of LAK activity. Resistance to transplantable lymphoma was equal to that of age-matched control mice. Polyinosinic-polycytidylic acid (Poly I:C) treatment resulted in immunomodulation in both control and Bu-pretreated mice. Twenty-four hours after Poly I:C injection, control and Bu-treated mice had higher levels of NK activity than did normal age-matched control mice, but the NK activity of Poly I:C/Bu-treated mice remained significantly lower than that of Poly I:C/control mice. The super-normal levels of NK activity in control and Bu-treated mice following Poly I:C administration were attributable, in part, to endogenous LAK activity. The generation of splenic LAK cells in vitro and target binding cells, which were reduced in Bu-pretreated mice, normalized following treatment with Poly I:C. Poly I:C treatment caused an increase in both IL-1 and IL-2 production in control and Bu-pretreated mice and in the ability of the treated mice to reject transplanted lymphoma cells. These results suggest that repeated injections of Bu decrease NK and LAK activity, but do not eliminate NK and LAK precursor cells. Thus, treatment with agents that increase IL-2 and/or interferon production can activate these cells to become effective killers and counter the long-lasting immunosuppressive effects of chemotherapy.

Collagen crosslinking and cartilage glycosaminoglycan composition in normal and scoliotic chickens

The amounts of lysine-derived crosslinks in collagens from tendon, cartilage, intervertebral disc, and bone and changes in the composition of sternal cartilage glycosaminoglycans were estimated in two lines of chickens, a control-isogenic line and a line that develops scoliosis. In the scoliotic line, scoliosis first appears at 3-4 weeks and progressively increases in severity and incidence so that 90% of the birds express the lesion by week 10. We have reported previously that cartilage, tendon, and bone collagens from scoliotic birds are more soluble than corresponding collagens from normal birds. Herein, collagen crosslinking and altered proteoglycan metabolism are examined as possible mechanisms for the differences in collagen solubility. At 1 week of age there were fewer reducible crosslinking amino acids (hydroxylysinonorleucine, dihydroxylysinonorleucine, and lysinonorleucine) in collagens from sternal cartilage and tendon in the scoliotic line than in the isogenic line. However, by week 3 and at weeks 5 or 7 values were similar in both groups. The amounts of hydroxypyridinium in vertebral bone and intervertebral disc collagen were also similar in both groups of birds. Consequently, differences in collagen crosslinking do not appear to be a persistent developmental defect underlying the expression of scoliosis in the model. However, differences were observed in cartilage proteoglycans and glycosaminoglycans from the scoliotic line that were not present in cartilage from the isogenic line. The average molecular weight of the uronide-containing glycosaminoglycans was 30% less in the scoliotic line than in the isogenic line, i.e., 12,000 compared to 18,000. The size distribution of cartilage proteoglycans from the scoliotic line also differed from that of proteoglycans from the isogenic line.(ABSTRACT TRUNCATED AT 250 WORDS)

IRX: an information retrieval system for experimentation and user applications

IRX is a text retrieval system designed to be a testbed for conducting information retrieval research on statistically-based retrieval strategies in either batch or interactive modes. The modular structure of IRX has permitted major changes in components of the system (e.g., ranking algorithms, parsers, interfaces; without redesign. As an interactive system IRX is in use at the Johns Hopkins University and the Lister Hill Center providing access to databases in human and molecular genetics.

An optimal morphometric method for quantitating wound epithelization

A new, inexpensive method for quantitative evaluation of reepithelization of shallow split thickness wounds in piglets is described. Wounds, 2.2 X 2.2 cm and 0.4 mm depth are inflicted by an electro-keratome knife in domestic piglets. At a specific time after wounding, the wound area is excised and processed for histology. A computer simulation, based on a randomized systematic sectioning of an entire wound, was used to conclude that only eight sections from the 2.2 X 2.2 cm wound are needed for the final evaluation. The results showed that the above method allows for determination of the epithelization magnitude within +/- 5% at a 95% confidence limit. It was found that in 15 kg piglets 50% epithelization of the above wounds was achieved in 65 hr; however, there exists a great interindividual variability. The rate of epithelization is age dependent and significantly faster in 7 kg body weight piglets than in those weighing 40 kg. The epithelization rate was the same at both the wound edge and the center of the wound, stressing the importance of hair follicles as a source of epithelization.

The QIP form: the one-page quality assurance tool

Recognition of the need to document and track corrective action plans led to the development in 1980 of the quality improvement plan (QIP). The QIP form includes ten categories such as quality assurance (QA) assessment and initiator's recommendation; it helps provide information for the hospital QA committee and the QA program. The QIP form has helped identify 50 current QA concerns at the Methodist Hospital of Indiana, Inc., in Indianapolis indicating its successful implementation.

Intraoperative sonographic monitoring of reduction of thoracolumbar burst fractures

Intraoperative real-time sonography was used to monitor surgical reduction of acute thoracolumbar burst fractures in eight patients. Real-time sonography was performed after laminectomy through a saline-filled operative field using either a 5.0 or a 7.5 MHz transducer. Sonography was performed during Harrington rod distraction and during fracture reduction to confirm adequacy of decompression of the spinal canal. This technique is useful to monitor surgery and in defining adequate fracture reduction.

Spondylarthrography: the demonstration of spondylolysis by apophyseal joint arthrography

Twenty selected patients with spondylolysis have been studied following apophyseal joint arthrography. In each instance a communication with the defect of the pars interarticularis was demonstrated by the extension of contrast medium from injection into the adjacent facet joint. The clinical and radiological features are described. The anatomical basis of the abnormality is presented using macroscopic and radiographic correlation from a dissected cadaveric specimen of spondylolysis. Sixty-five per cent of the patients experienced significant relief of pain symptoms when long-acting local anaesthetic was introduced into the facet joint.

Norepinephrine stimulation of phospholipid methylation in rat cortical synaptosomes: fact or artifact?

Synaptosomes from rat cerebral cortex incubated with 3H-S-adenosyl-L-methionine (3H-SAM) displayed an increase in chloroform- extractable tritium when norepinephrine was added to the reaction mixture. The products of this mixture were maximally generated from intact synaptosomes, only partially inhibited by propranolol, and not enhanced by exogenous phospholipids. Thin layer chromatographic analysis of these chloroform extracts in three solvent systems yielded large norepinephrine- stimulated peaks of radioactivity that did not consistently co-chromatograph with authentic methylated phospholipid standards: phosphatidylmonomethylethanolamine (PME), phosphatidyldimethylethanolamine (PDE), and phosphatidylcholine (PC). Further, attempts to identify these peaks of radioactivity using as standards several putative methylated products of varied chemical classes, failed to elucidate likely candidates. It appears that while norepinephrine markedly stimulates the amount of tritium extracted into the chloroform phase, careful and positive structural elucidation of formed products is required before it can be concluded that these are indeed methylated phospholipids.