Arthrographic pseudoloosening of Marmor total knee in hemophilic arthropathy: report of a case

The interpretation of loosening on the basis of contrast flow about the cement-bone interface in arthrograms of total knee arthroplasties includes special considerations. The first is that arthrography is misleading in the presence of severe cystic changes. The second is that clinical criteria should be given priority before concluding that there is loss of fixation of the prosthesis.

Resistance to Trypanosoma brucei in mice following inoculation of NTG-treated trypanosomes

The alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (NTG) was tested as an attenuating agent for Trypanosoma brucei. Parasites were treated with 4 mcg/ml NTG and injected into mice at intervals of 7-14 days. Those mice surviving four injections of NTG-treated trypanosomes were later challenged and showed a 100% resistance to infection. A corresponding group of control mice showed a 6% resistance to infection.

The use of freeze-dried allogeneic bone in oral and maxillofacial surgery

Clinical experience with 36 cases using freeze-dried allogeneic bone is reported. Its use in a variety of surgeries, including ridge augmentation, mandibular and maxillary osteotomies, mandibular reconstruction, midfacial advancement and obliteration of cystic cavities was associated with a minimal incidence of complications and excellent host acceptance. The collection of bone under sterile conditions and the rigid criteria for the tissue banking process are shown to account for this host compatibility and low complication rate. The physiochemical and biologic properties of freeze-dried allogeneic bone are discussed. This material provides unique practical advantages leading to long-term stability.

A simple highly sensitive methods for the determination of cell viability using an electronic particle analyzer, Coulter counter

Determination of cell viability is a procedure which is applicable to a number of techniques utilized in cell biology. Many means of determining cell viability have been proposed, each with its specific drawbacks. We present here two techniques for determining the viability of cells using an electronic particle analyzer, the Coulter counter. Viabilities of various tissue culture lines could be determined by comparing the ratios of live and dead cells obtained from a histogram of cells suspended in an isotonic solution or a solution of half-normal ammonium chloride (1/2 ACK). Viabilities obtained in this manner correlated well with those obtained by trypan blue dye exclusion. Viabilities of normal lymphocytes could be found in a similar manner by separating live and dead cells on histograms generated at high aperture currents. These values, though generally correlating well with dye exclusion data, may reflect determination of different criteria of cell death than previously used. The application of these techniques to a number of biological assays is discussed.

The study of analgesics following single and repeated doses

The efficacy and safety of 0.3 mg buprenorphine on single and repeated intramuscular administration (every 4 to 8 hours as needed) were compared to those of 10 mg intramuscular morphine. Fifty adult patients experiencing moderate to severe postoperative pain were evaluated up to three days following surgery. Results showed that 0.3 mg buprenorphine was as effective as 10 mg morphine, whether given as a single dose or on a repeat-dose schedule. The patterns of analgesia were similar and without indication of increasing dosage requirements with time. Minor side effects encountered were brief and minimal, including such conditions as drowsiness, dizziness, diaphoresis, flushing, and nausea.

Addicted physicians. A closer look

Fifty physicians were evaluated and treated in a psychiatrically oriented, short-term addiction program. Psychopathology ranged from overt schizophrenia to no demonstrable psychiatric syndrome other than the addiction. Physicians experiencing addiction problems before age 40 years were more likely to exhibit serious psychopathology in the borderline range, while physicians older than 40 years were more likely to exhibit organic brain impairment and depression. Treatment outcome had some relation to psychiatric diagnosis but no relation to the addictive agent.

Correction of hemifacial microsomia

Hemifacial microsomia is a combination of malformations of the first and second branchial arch derivatives. Reconstruction of three adult cases of hemifacial microsomia with varying degrees of deformity was presented.

Elimination of noise in telemetry systems by pulse-width discriminator

A pulse-width-discriminator circuit (PWD) was developed and applied for noise reduction in an FM pulse-interval-ratio modulation telemetry system. The PWD was incorporated as an intermediary between the tuner and the demodulator. The application of the circuit as a noise filter is a result of its ability to distinguish between pulses of different durations and its ability to eliminate pulses whose durations are less than some predetermined value. Since spikes of radio-frequency interference (RFI) occurring at the tuner output were of significantly shorter duration than the encoding pulses, they were virtually eliminated by the PWD. This prevented false triggering of the demodulator and resulted in a noise-free final demodulated output signal. This system was tested during telemetered blood pressure measurements in an unrestrained dog and proved to be extremely effective in eliminating spurious noise caused by electromagnetic interference in the radio-frequency range.

Cardiopulmonary resuscitation: a teaching aid

Laboratory dogs are used to demonstrate and practice cardiopulmonary resuscitation (CPR) procedures. Cardiovascular collapse, cardiac arrest, and ventricular fibrillation are produced in anesthesized dogs and then managed by the student. The laboratory exercise focuses and emphasizes CPR material taught in the classroom and on mannequins. With the current emphasis on CPR training and certification, we recommend the concept to the dental profession as an added dimension in teaching CPR.

The acutely injured wrist and its residuals

Carpal injuries are confusing and treacherous. Understanding the mechanisms are important in diagnosis and treatment. The mechanisms of extension, intercarpal supination and ulnar deviation can lead to most of the fractures and dislocations of the carpus and distal radius. Internal fixation of some avulsion type fractures will stabilize the wrist. Most carpal fractures and dislocations occur in the vulnerable perilunar zone consisting of the trapezium scaphoid, the head of the capitate and the tail of the hamate and the lunar border of the triquetrum. Carpal injuries occur in 3 stages. They start on the radial side, progress to the central carpals and end on the ulnar side. Stress roentgenographic views obtained acutely can aid in determining the type of injury present and its stability. Chronic residuals include: articular damage, carpal collapse, and contractures, intercarpal, radiocarpal and radioulnarinstability and skeletal loss or defects.

Carpal dislocations: pathomechanics and progressive perilunar instability

The pathomechanics, ligamentous damage, and degree of carpal instability in perilunate and lunate dislocations were analyzed by experimentally loading 32 cadaver wrists to failure. Thirteen perilunate and two lunate dislocations were produced. The mechanism of injury was extension, ulnar deviation, and intercarpal supination. These dislocations occurred in a sequential fashion due to progressive and specific ligamentous disruptions and were classified according to the degree of perilunar instability (PLI). Stage I perilunar instability (scapholunate diastasis) had the least degree of carpal instability. Lunate dislocations (stage IV PLI) had the highest degree of carpal instability. Radial styloid fractures were produced in seven as a result of avulsion. Scaphoid rotation was created in eight and was due to rupture of the radioscaphoid and scapholunate ligaments. Reduction was accomplished by reversing the mechanism of injury--that is, intercarpal pronation, radial deviation, and palmar flexion. Stress roentgenograms employing longitudinal carpal compression in radial and ulnar deviation were helpful in determining the degree of associated carpal instability.

Engineering technology and behavior analysis for interdisciplinary environmental protection

Engineering strategies for saving environmental resources have been widespread. However, many of those engineering advances have not been widely accepted nor generally applied by large segments of the general population. This paper considers the need to examine behavioral/environmental variables in the application of engineering technology, with particular reference to specific behavioral strategies for encouraging the use of engineering technology from an interdisciplinary perspective. A model for the study of factors contributing to the solution of ecological/environmental problems is presented and examples of interdisciplinary research are described. The model implies a need for the examination of the effects of antecedent and consequent manipulation of a variety of variables including: behavioral, physiological, environmental, technical and legal conditions. It is concluded that while interdisciplinary research efforts between engineering technologists and behavioral analysts are necessary, they have not received sufficient attention in the literature nor have they focused on the comprehensive study of antecedents and consequences as they relate to ecological/environmental problems. Thus, an extended "family" of research efforts is important for the success of these efforts.

In vitro synthesis of tissue-specific type II collagen by healing cartilage. I. Short-term repair of cartilage by mature rabbits

The healing of surgically induced defects in mature rabbits' hyaline cartilage was examined histologically and biochemically. The subchondral bone underneath the lesion was the source of repair. At the end of the first month, mushroom-shaped chondroid buds were seen sprouting from the subchondral bone. By the tenth week, these buds fused to a cartilagenous plug filling the lesion. The repaired cartilage synthesized Type II collagen.

Computerized tomography in oral and maxillofacial surgery

Computerized tomography has revolutionized the art of diagnosis by noninvasive techniques. Until recently, its use in oral and maxillofacial surgery has been limited. Basic principles include the production of a two-dimensional image representing an anatomically accurate slice of tissue. Advantages of computerized tomography are lack of image superimposition, preservation of detail of soft tissue, enhancement of vascular tumors, selective enlargement of areas of interest, tomographic capability, and the future possibility of the production of three-dimensional images. However, the presence of any metallic restoration produces artifacts, which limits the use of computerized tomography to areas excluding the dentition where restorations are present. Clinical application at our institution has been to use computerized tomography in the differential diagnosis of infections, midfacial trauma, vascular lesions, and lesions involving the mandibular ramus and maxilla.

Bone-mineral content, surface hardness, and mechanical fixation in the human radius. A correlative study

The bone-mineral content of seventeen intact forearms from eleven cadavera was determined by the non-invasive photon-absorptiometric scanning technique (Norland-Cameron Bone-Mineral Analyzer). Each radius was then removed and three surgical screws were implanted. The forces required to push out the screws retrograde were used to represent the security of mechanical fixation and were correlated with bone-surface hardness and bone-mineral content. A high degree of correlation (r = 0.89 or more) was found between bone-mineral content and the force required for extraction. A much lower correlation existed between surface hardness and extraction force (r = 0.30). We concluded that surface hardness does not correlate well with the screw-holding capacity of bone but that bone-mineral content, as determined by a non-invasive means, does so within a 10 per cent error.

CLINICAL RELEVANCE

This study demonstrates a high degree of positive correlation between bone density and the security of screw fixation in the human radius. Measuring bone density using a highly accurate, non-invasive, safe technique has clinical relevance in preoperative assessment of osteopathic patients who are being considered for internal fixation of the radius with plates and screws.

Relationships between the catecholaminergic and enkephalinergic systems demonstrated by a combined technique of formaldehyde-induced fluorescence and immunocytochemistry

A technique for the localization of catecholamines and enkephalin in the same tissue section is described. Sections from rat brains prepared according to the Falck-Hillarp technique were examined by dark field fluorescence microscopy and then processed for immunocytochemistry for leucine-enkephalin (leu-enk) using the unlabeled antibody technique. In the medial hypothalamus the distribution of the catecholamines and enkephalin is complementary, while in the lateral hypothalamus the patterns are similar but not identical. Enkephalin terminals are also observed in and around the locus coeruleus, while enkephalin cell bodies are adjacent to the nucleus.

A modified approach to the ilium to obtain graft material

The ilium is a commonly utilized site for obtaining graft material for maxillofacial reconstruction. Pain, decreased mobility, and equivocal esthetics are complications sometimes encountered postoperatively with most current ilium harvesting techniques. A new approach to the ilium for obtaining marrow and cancellous bone was used in 26 cases during a one-year period. No complications encountered in the donor site. The technique is simple, allows simultaneous procedures, and is esthetically acceptable.