Fine structure of fetal rat calvarium; provisional identification of preosteoclasts

Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.     

Surgical treatment of symptomatic subependymoma of the nervous system. Report of five cases

Subependymomas are uncommon and relatively benign tumors with a distinctive histological appearance. They are generally asymptomatic and most of them are found incidentally at postmortem examination. These tumors are usually located in the fourth and lateral ventricle, and sometimes in the spinal cord. The authors present a series of 5 pure subependymomas of the central nervous system all of which were symptomatic and all of which were treated by microsurgical removal. The clinicopathological findings and the results of microsurgical treatment in this series are presented.     

Epidemiology of bladder cancer]

The urinary bladder cancer mortality varies in different countries. The highest rates are noted in Denmark, UK, Belgium and Italy, the lowest rates in Japan, Singapore and Venezuela. The mortality rates are increasing for both males and females. In France, the highest rates are observed in the South of France contrary to other cancer sites. The highest incidence rates are observed in Europe, in USA and in some countries of Africa. In these same areas, the rates are higher for males and are increasing with time. The mortality is high in the first years after diagnosis. The five-year relative survival rates are 41%, for males and 35% for females. Tobacco, and especially cigarettes, is a well known risk factor. A dose effect relation appears to exist. The occupational risk factors are potentiated by tobacco and modifications are noted and are in relation with new factors. Ground coffee is associated with urinary bladder cancer and appears to be a co-carcinogenic factor with tobacco. Some drugs, such as antimitotics, phenacetin, radiation and urinary bilharziosis, are etiological factors of this cancer. The role of artificial sweeteners, alcohol and nutrition is less well documented.     

Analysis of the topics of a scientific paper

The items of a scientific paper are described and its contents are objectively analyzed. The title, the most powerful weapon to attract the reader should be short and bring up the information regarding the ideas within the article. The Introduction situates the reader, showing concisely the relevancy of the study. The purpose of the study the main question that should be answered along the article--should be written at the end of the Introduction. In Methods, the most used types of samples in the medical field are reported and analyzed. The different ways to display the Results and the special forms to express the data such as the use of tables and graphics are analyzed. The logic of the Discussion, respecting the sequence of the items of a scientific paper and the results obtained by the author are compared with the literature data. The Abstract written by items (structured) and the References and its situation on the text are also analyzed.     

Results of replantation of limbs

Authors describe 7 cases of limb replantation in their material. The field of indication is reviewed, the early postoperative complications and the possibilities of their treatment are discussed. The means of reaching the possible best results are examined. The ways of performing the possible optimal limb replantation are scheduled on the basis of their own experiences.     

Tumors of the retroperitoneum

Most of the retroperitoneal tumors (not originating from organs) are extremely rare (0.1% of all tumors) and are malignant. Clinical signs occur only late, are non-specific and are related to extreme tumor size. The most frequent tumors are malignant fibrous histiocytoma, liposarcoma, leiomyosarcoma, rhabdomyosarcoma, hemangiopericytoma and neurogenic tumors. The relevant clinical and morphological findings of these tumors as well as prognostic features are discussed.     

Regeneration of Hemofiltrate by Anodic Oxidation of Urea

Urea can be oxidized electrochemically in a chloride solution to carbon dioxide, water, and nitrogen. The microkinetics of this hypochlorite-mediated urea oxidation are elucidated. Based on this kinetic information, the optimal conditions and construction principles for an electrochemical reactor are deduced. The construction of a cheap, disposable oxidation cell and necessary auxiliary equipment are described. In vitro data are reported for urea removal. A 36-L volume was used to simulate a 60-kg patient; 18 L was recirculated through a 0.12-m2 oxidation cell. Within 3 h, 35 g urea could be removed from the system. The technical and economic possibilities as well as safety requirements for hemofiltrate regeneration to a reinfusable substitution solution by anodic urea oxidation are discussed critically. Although the process does not appear to be economically practical for discontinuous hemofiltration, it might be desirable for continuous (24 h/day) treatment.     

Measurement of humidity

This article describes the physical chemistry of evaporation with particular relation to water. The concept of humidity is defined, and factors that influence humidity are discussed in a practical context. The clinical importance of measurement and control of humidity is illustrated. Commonly used methods of measuring humidity are described and their underlying physical principles are explained.     

Surgical treatment of degenerative osteoarthritis of the fingers

Degenerative osteoarthritis of the long fingers is rare and surgical management is often necessary if there is joint pain, however this indication should not only be based on radiographic imaging. The specific anatomical problems of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are described. The surgical approach for each joint is described as well as functional management, in particular that of the extensor apparatus. Mobility should always be preserved for the MCP, arthroplasties are recommended for the PIP except for the index, and arthrodesis for the DIP. The different and most frequently used implants are described as well as the indications and expected results. The indications are discussed in relation to the limited results in the literature as well as the preferences of a panel of French hand surgeons.     

The results of prosthetic replacement in fracture-dislocations of the upper end of the humerus.

Eleven patients with fracture-dislocation of the upper end of the humerus treated by a Neer prosthesis are reviewed. The results of treatment are very disappointing. The complication rate is high. From these results in a small series, it would appear that prosthetic replacement of the humeral head does not offer the patient any significant advantage when compared with other reported methods. The possible cause of these poor results are discussed.     

Retarded ejaculation and anejaculation without orgasm. Apropos of the results of studies and of treatment in 60 cases

The physiological mechanism of ejaculation is recalled. The different kinds of abnormalities of ejaculation and their etiologies (drugs, post-surgery, neurological, endocrinological, psychological) are specified. The diagnosis and the therapeutical management of the different varieties are discussed and the results of a personal experience of 60 cases are reported.     

Ultrastructure of hemangio-endothelioma of the bone

Specimens of hemangio-endothelioma of bone from 3 patients were prepared and scrupulously analyzed with light and electron microscopes. The main findings are summarized as follows: (1) The tumour cells are of endothelial nature to form vascular spaces lined with atypical endothelial cells which bulge into the lumen. (2) Most tumour cells have a good number of organellae, especially plasmic vesicles and filaments in cytoplasm. (3) Many tumour cells are closely opposite with bridging granules in between. These features are the differentiating points of hemangio-endothelioma from other bone tumours. The plasmic vesicles are of particular interest in their function which has not yet been made clear. They may either be a structure for transporting large molecular substance including endocytosis, intracytosis and exocytosis, or a temporary storage of membrane or of plasma.     

Restoration of the shape, location and skin of the severe burn-damaged breast

Thermal injuries to the anterior chest in pre-pubescent girls result in breast contracture. During puberty, the breast parenchyma develops and grows underneath the scars, resulting in being flattened and disfigured. The breast mound, as well as the nipple–areolar complex, is partially or completely levelled out and displaced. The contours are unclear and the inframammary fold is effaced. This feature of the most severe breast contracture still poses a challenge for most surgeons. This type of breast contracture can be successfully eliminated with the author-suggested, improved free-skin grafting technique. The scars are excised and the shifted area of parenchyma is mobilised symmetrically to the border of the undamaged breast. Then, the shape and positioning of the breast as well as the nipple–areolar complex are reconstructed with the help of circular suturing through the fat layer on two to three breast levels. The suture ends are led beyond the wound area and are affixed with certain tension contralateral to the breast displacement. The suture ends, being in state of tension, are tied into untied knots around bolsters and are retained in place for about 3 months. During this time, the form and the positioning of the breast can be corrected using the traction of the untied sutures; the skin transplants are stabilised, under which the scar tissue is formed. Skin transplant and the scar tissue hold the shape and positioning of the breast and the sutures can be removed at this stage. In this series, 11 patients were operated upon and 13 breasts were reconstructed. Good results were achieved in all cases: the breast's shape and skin was restored and the positioning was corrected.     

Primary malignant tumours of the bone

Primary bone tumours are rare, with approximately 400 new cases per year in the UK. The diagnosis of bone tumours are hampered by delays in presentation. Radiographic changes are often characteristic for each type of bone tumour and should alert the physician to investigate further. Investigations should include blood tests, local staging and systemic staging. MRI, CT of the chest and isotope bone scans are important in evaluating the tumour. The most common types of bone tumour are osteosarcoma, chondrosarcoma, Ewing sarcoma, spindle cell sarcoma of bone and chordoma. The important pathological features and treatment of each type of tumour are described in this article. Early contact to a supra-regional bone tumour unit is mandatory when a bone tumour is suspected, where a multidisciplinary team approach is employed for an accurate diagnosis and appropriate management. Biopsy and surgical treatment should only be undertaken in such a unit and all patients should be enrolled in international clinical trials, where feasible, to gather data that will ultimately improve outcomes. The survival rates from most bone tumours are of the order of 60–80% with appropriate treatment.     

Pathology of tumours of the kidney and urinary tract

The urinary tract encompasses the kidney and the urinary collecting system, ureter, bladder and urethra. Benign lesions of the kidney include angiomyolipoma and renal oncocytoma. The main subtypes of renal cell carcinoma include clear cell, papillary and chromophobe variants. Prognostic factors reported by pathologists are reviewed, including the current grading and staging systems. Urothelial tumours include urothelial carcinoma in situ, papillary urothelial carcinoma and invasive urothelial carcinoma. Aspects of their grading and staging are covered, and several less common variants and benign urothelial lesions are mentioned. General aspects of core biopsy and resection specimens for renal disease are examined, including indications for frozen section examination.     

Experimental evaluation of adaptive identifiers

Transient response and tracking characteristics of three adaptive identifiers are illustrated and compared experimentally through digital simulation. Focus is placed on series-parallel (SP) identifiers, with and without auxiliary error signals. The identifiers are algorithms which have adjustable coefficients and are designed to follow the process output. At each computational cycle, the coefficients of the identifier (and the error signals) are updated in response to the tracking error between the process and identifier outputs. The process is simulated on an EAI TR-20 analogue computer, and the identification algorithms are implemented on a PDP-11/40 minicomputer. Testing is distributed over three processes commonly encountered by the control engineer. Variable adaptation gains, which are positive functions of the absolute value of the tracking error, accelerate the convergence of the identifiers. The experimental results are summarized in terms of the computational requirements of the identifiers.     

Results of primary reconstructive arthrodesis of the calcaneus (study of a homogenous series of 55 fractures of the medical surface of the calceneus)]

55 cases of calcanear fractures (thalamus) have been treated with the Stulz procedure (early subtalar arthrodesis and calcanear reconstruction), associated with a repair of the great apophyse. All the cases are comparable and the results are considered as good or excellent in 93,8 p. 100 of them. The results are interpreted accordingly to subjective and objective tests. The result is depending of the type of the lesion, the patient's profession and the nature of the trauma. The result obtained at the time of fracture uniting will stay stable, will never deteriorate and sometimes improve. The early arthrodesis and reconstruction remains a good procedure for the comminutive fractures of the thalamus, which are considered as the most difficult to correct perfectly. For this reason, the simple reconstruction is often responsible of secondary subtalar arthrosis.     

Management of metacarpal fractures

The metacarpal fractures are common fractures which are treated by orthopaedic surgeons, plastic surgeons and hand surgeons equally. These are seen in young adults who have active life style. These have a major impact in life style of the patients if these are not treated adequately. The management of the fractures vary among surgeons to surgeons; two surgeons in the same centre can have a different treatment plan for a fracture. There are no standard guidelines for the treatment and it ranges from conservative management, Kirschner’s wire (K-wires), plates and screws. This review article is about the management of metacarpal fractures where the commonly done procedures are reviewed.     

Pathology of tumours of the kidney and urinary tract

The urinary tract encompasses the kidney and the urinary collecting system, ureter, bladder and urethra. Benign lesions of the kidney include angiomyolipoma and renal oncocytoma. The main subtypes of renal cell carcinoma include clear cell, papillary and chromophobe variants. Prognostic factors reported by pathologists are reviewed, including the current grading and staging systems. Urothelial tumours include urothelial carcinoma in situ, papillary urothelial carcinoma and invasive urothelial carcinoma. Aspects of their grading and staging are covered, and several less common variants and benign urothelial lesions are mentioned. General aspects of core biopsy and resection specimens for renal disease are examined, including indications for frozen section examination.     

Optimal control of deterministic epidemics

Various deterministic optimal control models for SIR‐epidemics are investigated in this paper. The epidemics are governed by a rather general interaction, which covers most cases studied in the literature. Vaccination, quarantine, screening or health promotion campaigns as forms of control are considered. In all cases one finds a maximum effort control on some initial time interval. In addition, uniqueness and monotonicity properties of these models are studied. The results are also extended to the infinite time‐horizon situation. Copyright © 2000 John Wiley & Sons, Ltd.