Simultaneous bilateral patellar tendon avulsion in an adolescent.

A 13-year-old boy sustained an injury to both knees upon landing after a forceful jump in a soccer game. Plain radiography and magnetic resonance imaging demonstrated bilateral distal patellar tendon avulsions without fracture of the tibial tuberosities and the physes. To our knowledge, this particular injury has not been previously described in the literature. Open surgeries and internal fixation were performed with excellent functional outcome. This type of injury was similar to the well-recognised acute tibial tuberosity avulsion fracture in terms of the pathogenesis and treatment. We propose a further subtype of this injury pattern.

The need for DSA certification: the dental surgeons' perspective.

This study investigated the perceptions of dental surgeons on training and performance of Dental Surgery Assistants (DSAs). A questionnaire survey was sent to all practising dental surgeons in Singapore. It was found that 8.2% of respondents felt that the current standard of DSAs was good while 80.5% felt that the current standard was either adequate or poor. 71.5% felt that there was a need for DSA certification and 76.5% reported that they would send their DSAs for certification training. The results suggest an underlying need for formal training towards DSA certification.

Cementless total hip arthroplasty in young Chinese patients: a comparison of 2 different prostheses.

Sixty-one primary cementless total hip arthroplasties were performed in 45 Chinese patients <40 years old. There were 27 Anatomic Medullary Locking (AML, Depuy, Warsaw, IN) prostheses and 34 Porous Coated Anatomic (PCA, Howmedica, Rutherford, NJ) prostheses. The average follow-up was 7.6 years (range, 3-11 years). Ten hips (16%) were reoperated; the reason was polyethylene wear with or without osteolysis in 7 hips. Osteolytic lesion was present in 34 hips (56%). The cumulative successful rate at 10 years was 67% using reoperation for any reason as the endpoint. The cumulative successful rate was 98%, however, if revision for aseptic loosening was used as the endpoint. The 2 prostheses did not show significant differences in most parameters except that the PCA hips had significantly more acetabular loosening (P =.02) and periprosthetic osteolysis (P =.01).

Charnley total hip arthroplasty in Chinese patients less than 40 years old.

Forty-seven total hip arthroplasties were reviewed in 33 Chinese patients who were <40 years old at the time of operation. The preoperative diagnosis was avascular necrosis in 40% of the hips. A Charnley prosthesis was inserted using early cementing techniques in every hip. The average follow-up was 14.9 years (range, 6.9-21.1 years). The mean preoperative Harris hip score was 43.8 (range, 26-74), and the mean score at latest follow-up was 87.7 (range, 74-99) for the surviving hips. Thirty hips (63%) were revised, and 1 hip was removed because of late deep infection. The main cause of failure was aseptic loosening of the acetabular component. Using revision and radiologic loosening as endpoints, the cumulative survival rate for the acetabular component was 86.3% at 10 years and 27.0% at 15 years. The survival of the femoral components was 81.3% at 15 years. Patients with avascular necrosis had a higher failure rate than patients with other diagnoses (P =.001). An area of cement mantle that was <2 mm thick affected adversely the survival rate of the acetabular components (P =.04).

The performance of three vacuum-mixing cement guns--a comparison of the fatigue properties of simplex P cement.

We tested three commercially available cement-mixing systems (Howmedica, Summit and Stryker). After mixing the cement was allowed to cure in metal moulds under standard conditions. Sixty-nine cement blocks were produced. The fatigue behavior of the blocks was tested until failure. A wide scattering of results was observed in all the three systems. Uneven mixing of the polymer and monomer was observed in the Howmedica system. A significantly stronger cement (P=0.018) was produced with the Stryker system.

EICO-1: an orthodontist-maintained expert system in clinical orthodontics.

Expert systems are increasingly being used to provide comprehensive interpretative services for diagnosis and treatment planning. Some of these systems are constrained by the complexities of rule-based strategies and a need for knowledge engineers throughout the maintenance phase. A new approach to knowledge acquisition known as Ripple-Down-Rules was used in the development of EICO-1 (Expert Interpretation in Clinical Orthodontics). This expert-maintained system for automating orthodontic reports has a knowledge base of six hundred and eighty rules, and is maintained by an expert trained only in Orthodontics and without the help of knowledge engineers. EICO-1 is the first expert system in Dentistry to use Ripple-Down-Rules. It has potential as an interactive advisory tool and is applicable in a clinical situation.

Lingual orthodontics: a review of its history.

When lingual orthodontics was first introduced about twenty years ago some called it the 'ultimate aesthetic appliance'. Patients and practitioners embraced this new treatment alternative with high expectations. Reports of disappointing results and high costs dampened much of the initial excitement and enthusiasm gradually waned. By the late 1980s, the number of practitioners using the technique had fallen sharply, leaving only a handful who still believed in its potential. Relatively little has been written on lingual orthodontics, almost nothing in recent years. This article takes an objective view of its present status.

Chemical nature of a synthetic bilirubin conjugate and its reactivities in the total and direct reactions by the Jendrassik-Gróf method.

Using liquid chromatography, nuclear magnetic resonance spectroscopy, and elemental analyses, we verified that a commercially available synthetic bilirubin conjugate is predominantly a ditaurobilirubin (DTB) disodium salt. The Jendrassik-Gróf total bilirubin (TBIL) method quantitatively measures unconjugated bilirubin (Bu) and the Bu-equivalent content in DTB, from which we infer that the azopigments of Bu and DTB have identical molar absorptivities, which do not change in the presence of either serum or serum albumin of human or bovine origin. However, based on the ratio of direct bilirubin (DBIL) to TBIL, the DBIL reaction in dilute HCI is incomplete (even up to 20 min), with lower yields in a matrix of bovine serum albumin than in human serum. By contrast, the DBIL reaction in acetate buffer (pH 4.75) is quantitative for DTB in human serum (or its albumin), but less so in bovine serum (or its albumin). DTB is water soluble, is relatively stable when lyophilized with human serum, and is determined with such high precision in the above-mentioned endpoint assays that it may be a suitable surrogate calibrator for conjugated bilirubin.

Lectin histochemistry of complex carbohydrates in human cervix.

Complex carbohydrates in the human cervix were studied histochemically using lectins conjugated to horseradish peroxidase and correlated procedures. Stratified squamous epithelium of the exocervix and columnar epithelium of the endocervix in some, but not all specimens showed staining for terminal alpha-N-acetyl-D-galactosamine, alpha-D-galactose, beta-D-galactose and alpha-L-fucose. The staining for alpha-N-acetylgalactosamine and alpha-galactose, the terminal sugars in blood group A and B antigens respectively, corresponded to a large extent with ABO blood type. One exception was the lack of staining for terminal alpha-N-acetylgalactosamine in endocervical secretions in three of nine blood type A patients. A second exception was the staining for terminal alpha-galactose in endocervical secretions in about half of blood type O and A specimens. The type and amount of glycoprotein formed by endocervical columnar cells differed according to location in superficial compared with deep portions of the glands and according to location at the junction with exocervix compared with the more internal regions. Staining of endothelial cells for blood group A and B antigens was confined to subjects of blood type A and B respectively, although three of nine type A specimens showed no lectin reactivity for group A antigen. Endothelial cells evidenced affinity for Ulex europeus I agglutinin demonstrative of fucose in all specimens. Mast cells disclosed lectin affinity consistent with the presence of terminal or internal mannose or N-acetylglucosamine residues. Two blood type O specimens were examined with conjugated lectins at the ultrastructural level. Secretory granules stained for content of terminal alpha-galactose, beta-galactose and fucose. These results support and concur with biochemical studies of complex carbohydrates in human cervical tissues. They reveal, in addition, the location of the blood group antigens in the human exocervix and endocervix and the marked heterogeneity among endocervical columnar cells in glycoprotein production.

Alterations in the proximal nephron of beige mice with the Chédiak-Higashi syndrome.

The proximal nephron of C57 beige mice with a genetic defect analagous to the Chédiak-Higashi syndrome (CHS) has been compared with that of normal C57 black mice. The concanavalin A-horseradish peroxidase (Con A-HRP) technique stained the brush border of the proximal straight tubule heavily in black mice and weakly in beige mice. In beige mice this method stained the brush border of the proximal convoluted tubules weakly and the brush border of the proximal straight tubules only negligibly. Periodic acid-Schiff staining showed no such difference between beige and black mice but revealed an increase distally in the size of the CHS inclusions in the proximal straight tubule of beige mice. Immunostaining visualized abundant lysozyme in the first portion of the proximal nephron but none in the more distal segments of beige and black mice alike. At the ultrastructural level, the proximal convoluted tubules of black mice contained two morphologic types of heterophagosomes, which apparently differed in accord with the stage of their development. Proximal straight tubules contained morphologically different heterophagic bodies. The mature stages of these heterophagosomes were greatly enlarged in CHS mice. With the periodic acid-thiocarbohydrazide-silver proteinate (PA-T-SP) method for localizing glycoprotein ultrastructurally, the microvillar brush border, apical invaginations of the plasmalemma, Golgi cisternae, and lysosomal inclusions stained selectively in the proximal nephron in both strains. The proximal straight nephron of beige mice after staining with the PA-T-SP method appeared depleted of the strongly reactive apical invaginations in some areas, particularly where large heterophagosomes bordered the apical plasmalemma. The enlarged secondary lysosomes of heterophagic origin in beige mice varied in showing both diffuse and focal PA-T-SP reactivity. Lysosomal acid phosphatase activity appeared decreased, and peroxisomes were normal in size but increased in number in the proximal nephron of beige mice.

Mast cell degranulation in beige mice with the Chédiak-Higashi defect.

The degranulation response of peritoneal mast cells to calcium ionophore A23187 and compound 48/80 has been compared by scanning electron microscopy and transmission electron microscopy in normal C57 black mice and C57 beige mice with a genetic defect analogous to the human Chédiak-Higashi Syndrome (CHS). These methods reveal granule secretion in response to the degranulating agents in mast cells of both normal and beige mice. The observations indicate that beige peritoneal mast cells retain the capacity to exocytose their granules upon stimulation and suggest that the defect underlying the formation of the mega-inclusions is not attributable to impaired degranulation.

Lysosome enlargement in the Chediak-Higashi syndrome.

The Chediak-Higashi syndrome (CHS) is characterized by the occurrence of large inclusions in granulocytes and other cells. Analogs of the human disease are known in several species. Severity of clinical manifestations and extent of neutrophil alteration correlate closely and decrease in the order: man, mink, and mouse. The megabodies in granulocytes of Aleutian mink with CHS represent abnormal primary lysosomes that develop through fusion between stored lysosomal granules. The CHS alteration in mink affects azurophil granules of neutrophils more severely than the granules of eosinophils or basophils and spares specific granules of neutrophils. Several other types of cells exhibit megabodies that apparently cause little or no dysfunction in beige mice showing the CHS defect. Mast cells in these mice contain enlarged storage lysosomes, and Type II pneumocytes and gastric chief cells show enlarged secretory granules. Gastric chief cells, parietal cells, and hepatocytes enclose hypertrophied secondary lysosomes that function in autophagy whereas proximal renal tubules and cultured fibroblasts display hypertrophic secondary lysosomes of heterophagic nature. The cell distribution of megabodies in beige mice suggests they result from increased fusion between organelles delimited by membranes adapted to sequestration of hydrolytic enzymes.

An improved method for concurrent isolation of human granulocytes and lymphocytes. Its application in isoelectric focusing electrophoresis.

A modified method of Boyum's technique to isolate granulocytes and lymphocytes from human blood is described. The granulocytes and the lymphocytes separated by this isolation procedure are highly pure, viable, and in sufficient number for subsequent isoelectric focusing studies. Different proteins have been separated by isoelectric focusing. This technique can be useful in the investigation of granulocytic and lymphocytic disorders.

Cytochemical localization of glycoconjugates in rat peritoneal mast cells during degranulation.

Cytochemical methods for the localization of glycoconjugates including concanavalin A-horseradish peroxidase (ConA-HRP) and dialysed iron were used to study the distribution of glycoconjugates in mast cell granules during degranulation. The ConA-HRP method revealed intense staining of discharged mast cell granules. Dialysed iron staining was seen at the granule periphery, with extruded granules exhibiting more intense staining than undischarged granules.

Age and the spread of local anesthetic solutions in the epidural space.

Sensory level of anesthesia following the injection of 20 ml of 1.5% lidocaine with epinephrine (1:200,000) in 238 adult males averaged T7.7, T5.6, and T5.1 at 10, 20, and 30 minutes, respectively. Patient age had no significant effect on local anesthetic requirements per spinal segment per unit height until age 40 years, which age the calculated amount of local anesthetic decreased significantly to 0.62 ml from 0.69 ml/segment/meter of height. Above age 40 there was no further decrease in epidural anesthetic requirement with advancing age. Patient height was inversely related to sensory level (p < 0.001). Time required for anesthesia ro recede to T12 averaged 164 minutes and was slightly but significantly (p < 0.05) prolonged with advancing age.

Naturally occurring lymphoblastic leukemia in guinea pigs.

Nine cases of lymphoblastic leukemia were observed in 4,500 guinea pigs from three guinea pig production colonies during a period of 3 years. Seven of the cases occurred in strain 2/N, one in 13/N and one in Dunkin-Hartley/FD. These guinea pigs were 5.5-29 months old and included two males and seven females. Clinically, the animals showed a variety of signs, such as enlargement of peripheral lymph nodes, posterior paralysis and terminal ataxia. Gross lesions were characterized by numerous white spots and enlargement of the lymph nodes and many internal organs. Hematologic examination showed leukocytosis with lymphoblasts predominating. Histologic and cytologic examination of affected tissues and cells revealed generalized infiltration of lymphocytic leukemic cells.

In vitro and in vivo assessment of the viability of cryopreserved postmortem murine bone marrow cells.

The viability of cryopreserved mouse fresh and postmortem bone marrow cells was studied using methylcellulose clonal cell culture assay and the murine spleen colony technique. This study clearly indicates the presence of pluripotent hemopoietic stem cells in cryopreserved murine postmortem bone marrow cells. The viability of granulocytic precursors in both fresh and postmortem bone marrow cells was mildly to moderately decreased by the freezing process, while the proliferative capacity of erythrocytic stem cells is significantly decreased by cryopreservation. The results strongly suggest that frozen, fresh and cadaveric bone marrow bank for bone marrow transplantation may be of value.