Strongyloidiasis in immunosuppressed hosts. Presentation as massive lower gastrointestinal bleeding.

Two cases of massive lower gastrointestinal hemorrhage in immunosuppressed patients were due to complicated infestation with Strongyloides stercoralis. The very high mortality of disseminated strongyloidiasis may in part be attributed to delays in diagnosis and treatment resulting from the complex life cycle of this nematode. Successful therapy in the cases presented consisted of reduction of corticosteroid dosage, use of thiabendazole in excess of that recommended for uncomplicated infestation, parenterally administered nutrition, multiple transfusion of blood products, and vigorous supportive management. Emphasis is given to proper categorization of patients and measures designed to prevent, detect, and treat hyperinfection in patients in whom immunosuppression is anticipated.

Krypton fluoride excimer laser ablation of tooth tissues: precision tissue machining.

A variety of lasers using different wavelengths have been used to remove dental hard tissue. The infrared lasers produce their effects photothermally whereas ultraviolet excimer lasers remove tissue in a controlled and precise manner by photoablation. This study investigates the use of 248 nm laser radiation in the precision removal of both enamel and dentine using diffraction limited ultraviolet optics. The data showed that enamel and dentine were machined to a high level of precision (1-2 micron tolerances). The rate of removal was greater in dentine than enamel at a range of energy densities between 1.15 and 2.2 J/cm2. The method of removal of both tissues appears to be by the preferential ablation of the organic phases of each, exposing the anatomical details of their structure. An explanation of the possible method of ablation is proposed for these tissues.

Time course of the effect of flunarizine on rabbit isolated vascular muscle.

Flunarizine inhibited KCl contractions of the rabbit aorta, mesenteric artery and portal vein progressively over 3-4 h. The rate of development of block was approximately linear on a logarithmic scale and was similar for equieffective concentrations (aorta = 2.1 microM, mesenteric artery and portal vein = 0.21 microM). It is concluded that flunarizine can discriminate between calcium ion channels opened during the spike and those opened during sustained depolarization.

Choledochoscopy model.

Choledochoscopy is effective in reducing the incidence of retained biliary stones and for the removal of retained calculi through the T-tube tract. It has also been of value in performing complex reconstructive and diversionary procedures on the common duct. Knowledge of the biliary anatomy is a prerequisite for the development of skill in choledochoscopy. The use of a biliary endoscopy teaching model with stones has been very effective in teaching the techniques of biliary endoscopy. Experience with the choledochoscope and its accessories should precede its use for postoperative choledochoscopy.

Consistent, effective technique for muscle and nerve biopsy.

Muscle and nerve biopsy provides information of increasing importance in the management of neuromuscular disorders. A simplified technique is presented that yields a specimen which equals and often surpasses in quality specimens obtained by more complex methods that require specially designed clamps and forceps.

Unsuccessful postoperative extraction of retained common duct stones: an analysis.

An analysis of unsuccessful extractions of retained biliary calculi using basket catheters reveals more than half the failures are related to the selection, placement, and size of the T tube. A new T tube has been developed which will improve postoperative access to the common duct and facilitate removal of retained calculi.

Short-term extrusion of isolated teeth of adult monkey (Macaca fascicularis).

By means of a variable capacitance device, the occlusal movements of 12 fully-developed teeth were recorded in 6 adult monkeys. Sustained extrusion was seen, with rhythmic pulsations due to the heart beat and to breathing. Extrusion varied from 10 to 138 micrometers over periods of 40-360 min, and became progressively slower with time. Because of the protracted nature of the extrusion, it is probable that these tooth movements were caused by forces generated in the periodontal ligament resulting from biochemical changes in the periodontium rather than by vascular alterations, and occurred as a result of the removal of intrusive loads from the opposing teeth.

Short-term changes in the mesiodistal position of teeth following removal of approximal contacts in the monkey Macaca fascicularis.

A capacitance transducer was used to measure the changes in the distance between pairs of adjacent teeth following the removal of tooth contact. Ten pairs of incisors and cheek teeth were studied over periods of several hours in three adult monkeys. Compared with minor changes in control tooth pairs, there was a sustained approximation of the capacitance plates for periods up to 2 h. Removal of tooth contacts with the teeth adjacent to the test pairs of teeth caused separation of the plates. It is proposed that removal of approximal tooth contact allows the transseptal fibre system to contract and produce approximation of the adjacent teeth.

Tenckhoff catheter placement: surgical aspects.

A 3-year retrospective review of 110 consecutive Tenckhoff catheter placements was undertaken. Major complications were found in 3.6 per cent of cases and minor complications occurred in 30 per cent. Analysis of cases in which catheters failed revealed that obesity and prior abdominal surgery occurred in 75 per cent of these patients. Attention to these factors and the use of appropriate techniques of placement and, in special situations, the use of endoscopy and fluoroscopy have reduced the failure rate of these high-risk situations. Management of infective complications are outlined and should include continued antibiotic dialysis and catheter replacement only if persistent peritonitis or fungal peritonitis occur. With these guidelines, improved peritoneal dialysis can be undertaken with less morbidity to the patient.

Considerations in treatment planning for implant-supported auricular prostheses.

Improvements in planning for the provision of silicone auricular prostheses have been achieved with CT scanning. The analysis of information using a computer workstation has enabled preoperative determination of skull thickness and position of implants in relation to the proposed location of the prosthesis. The technique is of particular value in cases of craniofacial microsomia.

Three-dimensional nasal changes following maxillary advancement in cleft patients.

Three-dimensional laser surface scanning of the face was performed before and after Le Fort I maxillary advancement in 24 patients with replaced clefts of the lip and palate. The surgery resulted in advancement of the upper lip and para-alar tissues and an increase in the relative prominence of the nose within the face. These changes were produced at the expense of an increase in nasal width and a reduction in nasal tip protrusion. The changes in nasal morphology showed significant variation among patients.

Orthodontics in the National Health Service.

In order to, understand the development of the National Health Service, we need to look at the state of orthodontics in the country prior to its introduction in 1948. This article considers the various factors which contributed to orthodontics' development in the NHS. The progress of this specialty is described together with comments on its future in the NHS.

The three-dimensional effects of orthodontic treatment on the facial soft tissues--a preliminary study.

OBJECTIVE: To examine the three-dimensional effects of extraction and non-extraction orthodontic treatment on the facial soft tissues. SETTING: Department of Orthodontics, Royal London Hospital. DESIGN: Longitudinal study of two prospective cohorts of patients who were attending for orthodontic treatment. METHOD 12 patients were included in each group, in accordance with the selection criteria. Three-dimensional optical surface scans of these patients were obtained in the one month prior to having fixed appliances placed and this was repeated at the end of treatment. RESULTS: The average face of the non-extraction patients was of greater general dimensions than the extraction average, both at the start and the end of treatment. During the fixed appliance treatment, the vermilion of the upper lip became more protrusive to a similar extent in both groups in relation to the reference plane. The lower lip vermilion and the philtrum showed no change for either group over the treatment time. The labiomental fold area showed a slightly greater forward movement in the extraction group with treatment. CONCLUSION: Three-dimensional optical surface scanning allows data from the whole of the face to be assessed, as opposed to the lateral profile view used in the majority of the studies to date. The effects of the two types of treatment on the facial soft tissues were very similar, indicating that orthodontic treatment involving the extraction of teeth does not have a detrimental effect on the face.

An investigation of a group of 35 consecutive patients with a first arch syndrome.

Thirty-five consecutive patients with a first arch syndrome were divided into right and left sided and bilateral groups and were investigated clinically, radiographically and electromyographically. The patterns of muscle activity in the inter occlusal position were significantly different in each of the groups. The morphology of the jaw was related to the muscle activity. The implications of the findings are discussed.

Le Fort I maxillary osteotomy: is it possible to accurately produce planned pre-operative movements?

The planned preoperative maxillary movements for five groups of patients requiring orthognathic surgery were prospectively compared to the actual surgical movements achieved in the operating theatre. There was a very poor success rate in achieving predicted movements in all the patient groups. There is a need to test and implement a reliable method of assisting the surgeon in spatially orientating the jaws on the operating table.

A three-dimensional soft tissue analysis of 16 skeletal class III patients following bimaxillary surgery.

A three-dimensional soft tissue study of the results of surgery in a group of 16 skeletal Class III adult patients following orthognathic surgery was carried out using laser scans (Arridge et al., 1985). The patient group was compared to a control group of the same population. Laser scans were taken prior to surgery, 3 months post-surgery, and at least 1 year after retention. Preoperative comparison to the control groups revealed that the facial disproportion related to both the maxilla and the mandible. Le Fort I advancements resulted in broadening of the lateral aspects of the nose, advancement of the dorsum, and overcorrection of the alar bases. There was a degree of change over the cheeks bilaterally, because of alterations in the general drape of the soft tissues. There was a degree of overcorrection in the female group following mandibular set back but the male group were still more prognathic, when compared to the control group. There was a marked degree of relapse in the mandible from 3 months to 1 year postoperatively, with a resultant anterior movement of the maxillary arch. Laser scanning has proved to be a simple non-invasive method of measuring three-dimensionally, and is a very useful tool in auditing surgical outcome and measuring surgical relapse.

A three dimensional analysis of soft and hard tissue changes following bimaxillary orthognathic surgery in skeletal III patients.

The three dimensional changes in the bone and the ratio of soft tissue to bone movement were investigated in a group of 16 Skeletal III patients following orthognathic surgery. Computerised tomogram scans were taken for each patient pre-operatively and 1 year postoperatively. The scans were superimposed, radial measurements calculated, and the changes illustrated by two separate colour scales. There was no constant pattern of movement in the maxilla or mandible in these patients. However, following a Le Fort 1 osteotomy there was commonly a 1:1 ratio in the midline which increased to 1.25:1 at the alar bases and over the canine regions bilaterally. There was also a 1.25:1 ratio or greater over the chin and mentalis regions following mandibular set back.

An electromyographic study of post retraction orthodontic patients.

19 patients treated by the Begg technique 7 patients treated by the Edgewise technique and 15 cases treated by a functional technique who had been at from 1-10 years without any form of retention were recorded electromyographically and their patterns of activity compared with those of patients who had a normal occlusion and who had not received orthodontic treatment. In the interocclusal position the patients who had received functional treatment had a balanced activity and were similar to those with a normal occlusion but this was not so when biting on cardboard 0.5 mm thick. The Begg cases were balanced but the amount of activity was reduced by half; the Edgewise cases were balanced when biting on cardboards and were then similar to those with a normal occlusion.

The use of three-dimensional techniques in facial esthetics.

The three-dimensional nature of beautiful faces is analyzed and beauty is investigated by means of optical-surface scanning. This noninvasive technique is described and illustrated and its value in the assessment of beauty noted. Forty men and 40 women with a normal Class I skeletal pattern and a Class I occlusion were scanned and an average face was obtained for each group. The averages were compared with those derived from a group of 9 men and 15 women employed as professional models and the differences were noted. A group of normal Asian teenagers were scanned to investigate ethnic differences. The groups of professional models were further analyzed to see whether they measured up to the "golden proportions" described by the ancient Greeks. The groups did not fit the "golden proportions" and they represented instead a range of malocclusion and a wide range of cephalometric values.

[Lasers in dentistry 7. The use of 3D imaging in dentistry]. / Lasers in de tandheelkunde 7. Het gebruik van driedimensionale beelden in de tandheelkunde.

Optical surface scanning accurately records the 3D nature of the face non-invasively and quantitatively. Programmes to analyse the data now enable the clinician to compare the changes in the face as the result of growth or of treatment and also to average groups of patients to provide an assessment of treatment. An average face has been obtained from groups of patients each year from 5 to 18 years. Growth of an individual can be compared with the norm for that age to determine which areas of the face show abnormal growth. Prediction of facial form for forensic and surgical purposes is possible. Programmes have been developed that analyse shape and curvature of areas of the facial surface. Such an analysis can be used to determine the changes in the facial surface as the result of growth, treatment, or drug therapy and to study genetic effects.