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In order to reveal syncytia within the visceral musculature of Drosophila melanogaster, we have combined the GAL4/UAS system with the single-cell transplantation technique. After transplantation of single cells from UAS-GFP donor embryos into ubiquitously GAL4-expressing recipients, the expression of the reporter gene was exclusively activated in syncytia containing both donor- and recipient-derived nuclei. In the first trial, we tested the system in the larval somatic musculature, which is already known to consist of syncytia. By this means we could show that most of the larval somatic muscles are generated by clonally non-related cells. Moreover, using this approach we were able to detect syncytia within the visceral musculature - a tissue that has previously been described as consisting of mononuclear cells. Both the longitudinal visceral musculature of the midgut and the circular musculature of the hindgut consist of syncytia and persist through metamorphosis. This novel application of the transplantation technique might be a powerful tool to trace syncytia in any organism using the GAL4/UAS system.

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The larval gut of Drosophila is coated with visceral muscles of mesodermal origin. In the midgut region this musculature comprises circular and longitudinal fibres. The complete visceral musculature is described to be removed during metamorphosis and to be replaced by a newly differentiated imaginal tissue resembling the morphology of the larval musculature. However, progenitors of this imaginal visceral musculature have never been detected prior to differentiation. Here I present results indicating that the longitudinal visceral musculature of the midgut completely persists through metamorphosis. Single cells expressing green fluorescent protein (GFP) as a marker were transplanted at the blastoderm stage. All clones contributing to the longitudinal visceral musculature detected in third instar larvae were recovered after metamorphosis in adult flies. Further evidence for the persistence of the larval visceral musculature was obtained from the P[Gal4] insertion line 5053A. It expresses GAL4 specifically in the longitudinal visceral muscles of the midgut of all developmental stages to the adult fly beginning at the end of embryogenesis. By using GFP as a reporter, it was possible to follow these cells through the entire metamorphosis. Although the muscles undergo dramatic morphological changes including the loss of their contractile system, no evidence for a replacement of the larval visceral musculature by imaginal precursor cells was detected.

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We have examined the cell lineage of larval and imaginal precursors of the mesodermal anlage between 10% and 60% egg length (EL) by homotopic single-cell transplantations at the blastoderm stage. Clones in the larval somatic muscles and in the fat body were derived from transplantations everywhere between 10% and 60% EL along the ventral side of the embryo. Clones frequently overlap these tissues and can extend over a maximum of four segments in the larval somatic muscles or over two morphologically-distinct parts in the fat body. Clones in the gonadal mesoderm overlap with other mesodermal derivatives and exhibit different mitotic behaviour in the two sexes. We present a blastoderm fate map for the fat body, the larval somatic muscles and the gonadal mesoderm. Clones in the imaginal muscle precursors of the abdomen, as well as of the thorax, always show a common cell lineage with larval somatic muscles and partly with other mesodermal tissues. These clones of imaginal derivatives are always found within a single segment, while the overlapping clone parts in the larval somatic muscles can label up to three segments.

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In holometabolous development, higher insects have two different life forms, the larva and the imago. Both larval and imaginal cells are derived from cells of the blastoderm stage. After the final embryonic wave of mitosis, however, only the imaginal cells remain diploid, proliferate massively and do not differentiate until metamorphosis. The separation of these two pathways was described by many authors as a fundamental process that must take place at a very early stage of development, most probably the blastoderm stage. Mainly by using single cell transplantations at the blastoderm or early gastrula stages, respectively, we found common cell lineages between larval and imaginal structures by clones overlapping in the ectoderm (i.e. larval epidermal cells and imaginal discs within a segment, or larval and imaginal salivary gland cells), the mesoderm (i.e. larval somatic muscles and adepithelial cells), and the endoderm (i.e. larval and imaginal midgut cells). From these findings we conclude that it seems to be a principle in Drosophila embryogenesis that the separation of larval and imaginal pathways is postponed to a later developmental stage.

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Two cases of Coxsackie B viral meningo-encephalitis in pregnant women are described. Both patients recovered well and delivered healthy babies, but because of delay in establishing the aetiology of their infections both mothers, and one child, received acyclovir therapy. The differential diagnosis of non-pyogenic meningo-encephalitis in late pregnancy can present particular problems: clinicians caring for such women should remain aware of the potential for enteroviral infection in their patients, and take appropriate action to prevent cross-infection in neonatal units.

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The development of ultrasonically driven tools for revision joint arthroplasty is presented. The data represent seven-years' experience and include information from laboratory investigation and clinical experience from 20 surgical cases. Whole bone torsional strength studies reveal no decrease in strength parameters after the removal of cement ultrasonically. Comparison studies demonstrate that ultrasonic tools allow more rapid completion of cement and prosthesis removal than traditional manual tools. Histologic studies using an in vivo canine model demonstrate no deleterious effects to endosteal bone where cement had been removed by ultrasound. Clinical studies indicate that the use of ultrasound facilitates the surgery and causes no cortical perforations; the creation of cortical windows was not necessary in all cases. Ultrasound is safe and efficacious in cement and prosthesis removal during revision surgery.

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The subscapularis muscle and the distribution of its tendinous bands is of significance in the surgical management of the shoulder joint. This distribution pattern has not been previously described in detail. We feel that, in any anterior approach to the glenohumeral joint for fracture fixation, joint replacement, and soft tissue reconstruction, a thorough understanding of the distribution pattern of the subscapularis bands is essential. We examined the subscapularis muscles from five cadavers. Four sections from the lateral one-half of each muscle were custom-mounted and stained with Masson's trichrome. We found a consistent pattern in which the tendinous bands were evenly interspersed in the midportion of the muscle and condensed laterally into a single large, flat tendon in the superior two-thirds of the muscle. The inferior one-third remained muscular. Understanding this pattern should help the surgeon have confidence that he/she has obtained a more secure repair in procedures involving the subscapularis muscle.

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This conclusion of a two-part series examines the effects of ultrasonic cement removal from canine femurs on the underlying endosteal bone. The purpose of the investigation was twofold: to qualitatively assess the immediate in vivo effects on bone of direct coupling as a method of ultrasonic prosthesis removal, and to determine the immediate and delayed histologic responses of cortical bone to ultrasonic cement removal as well as compare the response after cement removal by high-speed burr instrumentation. This histologic study of an in vivo model demonstrated no significant cortical bone damage with the use of ultrasonically driven tools. The authors conclude that this method for the removal of bone cement and securely fixed prostheses is safe and efficacious.

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Ultrasonically driven tools (UDTs) have been developed to facilitate removal of bone cement and securely fixed cemented components during revision arthroplasty. A two-part study was performed to evaluate the efficacy and safety to these tools. Heat generation at the endosteal surface during prosthesis and cement removal with a UDT was examined in an in vitro human femoral revision model. The histologic changes produced by the UDT at the endosteal surface were evaluated with an in vivo canine model. The heat generation studies demonstrated one-degree (C) temperature elevations at the endosteal surface during cement removal. We conclude that UDT use is safe and effective in the removal of cement and secure prostheses during revision total hip arthroplasty.

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Cemented and uncemented prostheses removed from bone using ultrasonic tools were evaluated grossly, microscopically, and microradiographically. The findings in this study indicate that application of an ultrasonic tool to the intramedullary canal is a safe method for removal of a variety of components. In addition, when the energy is coupled directly to the metallic component, it can be separated from the cement-bone or prosthesis-bone interface instantly.

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We show that measurement of the temporal profile of the backscattered pulse has the potential to monitor the extent of cataract development in the eye.

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Thirty patients treated with transscleral neodymium:YAG laser cyclophotocoagulation (TSYLC) are reported. All patients had advanced glaucoma and had previously undergone one or more surgical procedures that failed, or were unsuitable for surgery. The average preoperative intraocular pressure (IOP) for the group was 43 +/- 12 mmHg. The average follow-up time was 6 months. The average energy level used was 3.8 J (range, 3.5-4.5 J). The patients were divided into two groups. Group 1 consisted of 20 patients in whom laser lesions were applied 3 mm from the limbus. Group 2 consisted of ten patients in whom laser lesions were applied 2 mm from the limbus. Success was defined as an IOP between 22 and 5 mmHg, regardless of the number of treatments required. The overall success rate was 86%. However, group 2 required significantly more retreatment than did group 1. Complications were moderate and transient.

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The feasibility of Q-switched Nd: YAG synechiolysis in phakic patients without visible damage to the lens has been demonstrated. The value of this procedure in the management of glaucoma and its advantages over argon laser photomydriasis is discussed.

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Twenty phakic eyes of 19 patients underwent Q-switched neodymium:YAG laser iridotomies for angle-closure glaucoma. Eleven eyes were previous argon laser failures. Penetration was achieved in each case with several shots in one session. Complications were minor and transient.

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