Arthroscopic proximal patella realignment and stabilization.

Treatment of patellofemoral pain is a source of much controversy. This is shown by the vast number of surgical procedures used in treatment. This article describes an arthroscopic proximal realignment technique to address patellafemoral pain and instability. We have used this technique to treat acute dislocations with capsular deficits, recurrent dislocations, and subluxations. This procedure was developed in 1988 as an alternative treatment to distal realignment in a 10-year-old child with recurrent dislocation of the patella. In adults, we have used this technique in conjunction with a lateral release and in two cases with a distal realignment procedure. Our experience is that low technical demand, consistency of results, low morbidity, and cosmesis make this a worthwhile technique. We believe that this procedure is a valuable technique either alone or in conjunction with other procedures in the treatment of patella maltracking and instability.

Optical logic using electrically connected quantum well PIN diode modulators and detectors.

We present new optoelectronic logic devices or circuits consisting of electrically connected quantum well PIN diodes capable of implementing any boolean logic function. One class of circuits uses single beams to represent the logic levels and compares their intensities to a locally generated reference signal. A second class of circuits routes signals as differential pairs. The connections of diodes in these circuits resemble the transistor connections in NMOS and CMOS logic families. We demonstrate simple optical programmable logic arrays (e.g., E = AB + CD) using both of these classes of circuits.

Spatial light modulator and optical dynamic memory using a 6 x 6 array of self-electro-optic-effect devices.

Using a 6 X 6 array of integrated quantum-well self-electro-optic-effect devices, we demonstrate an optically addressed spatial light modulator able to convert a visible, incoherent image into coherent infrared (IR) light. Depending on the IR wavelength used, the output is either a positive, binary-thresholded version of the input (bistable mode) or its linear, negative (self-linearized) mode. This device can also function as a dynamic bistable memory that can retain its internal state without power for times as long as 30 sec.

Ultrastructural investigation of the microsporidium Nosema cuneatum (Microspora: Nosematidae) in the grasshopper Melanoplus sanguinipes (Orthoptera: Acrididae) with emphasis on mitosis.

Ultrastructural investigation of the microsporidium, Nosema cuneatum, (Microspora: Nosematidae), a parasite infecting Melanoplus sanguinipes (Orthoptera: Acrididae). Stages in merogony and sporogony are apansporoblastic, occur in a diplocaryon arrangement and undergo binary fission. Nuclei are connected during karyokinesis in a dumbbell-like arrangement. Microtubules within the nucleus are either associated with the kinetochore or extend from spindle plaque to spindle plaque. Merogony stages in the host cytoplasm are surrounded by an intermittent layer. During sporogony, an electron-dense layer is deposited along the parasite plasmalemma. The spore is binucleate and the polar tube is isofilar, with between 10 to 12 polar tube coils in cross-section.

Cytogenetic assays for mitotic poisons. The grasshopper embryo system for volatile liquids.

The present study demonstrates the usefulness of grasshopper (Melanoplus sanguinipes) embryos for detecting mitotic arrest and anaphase abnormalities induced by volatile liquids. Eight compounds were tested with this system. Embryos in vivo (intact chorions) were suspended in sealed chambers and the agents, in various amounts, were placed on the bottom of the chambers. The agents, after evaporation, filled the ambient air in which the embryos respired. After a period of exposure, individual embryos were fixed for squash preparations to determine the mitotic index (MI) and the ratio of anaphases to metaphases (A/M). If an agent completely arrested mitosis at metaphase, the A/M ratio would be zero and the MI would be elevated if the agent does not prevent interphase cells from entering mitosis. Two common organic solvents, benzene and toluene, and two common anesthetics, halothane and chloroform, were found to be potent mitotic arrestants in the present system. Colchicine-like mitoses (c-mitoses) were observed in embryos after treatment of the above four agents; all of these agents except toluene were found to induce an accumulation of c-mitoses. Amyl acetate, 95% ethanol, deionized water, and camphor (in 10% ethanol) failed to show mitosis-arresting effects on the embryos. Abnormal anaphases with lagging chromosomes and multipolar spindles were observed in embryos which showed partial metaphase block after exposure to concentrations of benzene lower than that required for a complete block. Benzene, toluene, halothane, and chloroform have been implicated as teratogens and carcinogens, but are negative as mutagens, clastogens, and SCE inducers. Thus, the carcinogenic activity of these compounds appears to result from their action on cell division mechanisms.

Order measurements in plasma membranes from Duchenne dystrophy fibroblasts.

Plasma membranes have been isolated using different methods from Duchenne dystrophy and control human skin fibroblasts. Fluorescence techniques were utilized to resolve the rotational properties and the degree of hindered rotation of the fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene in the membranes. Under specific conditions of fibroblast processing and membrane fractionation, plasma membranes from Duchenne fibroblasts showed significantly less order (0.0125 greater than P less than 0.0025) and less hindrance to probe rotation than membranes from control fibroblasts. The order differences did not seem to be the result of heterogeneity in the membrane environment sampled by the probe. The frequency dependence of the fluorescence lifetime for diphenylhexatriene indicated no measurable contribution by a short lifetime component. Analysis of diphenylhexatriene rotation in the plasma membranes using the 'wobbling-in-cone' theory suggested that both the angle of probe rotation (theta c) and the rotational rate (Dw) were important parameters in understanding the variations between Duchenne and control membranes at 16, 22 and 30 degrees C. Electron spin resonance studies with 5'-doxylstearic acid at 25 degrees C confirmed our fluorescence results. The segmental motion exhibited by the spin label revealed less order in the Duchenne membranes.

Splenectomy and antiplatelet agents in thrombotic thrombocytopenic purpura.

Ten patients with thrombotic thrombocytopenic purpura (TTP) were studied retrospectively. The male:female ratio was 2:3 and the median age was 27 years. Six patients were alive one-half to 18 years after the onset of the disease. Four of these patients underwent emergency splenectomy and received antiplatelet drugs. Of the remaining two, one responded to splenectomy and the other had received a short course of aspirin therapy. The study supports the usefulness of splenectomy and/or antiplatelet agents in the treatment of TTP.

Respiratory dysfunction in thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, neurologic abnormalities, fever and renal dysfunction. in six of seven consecutive patients with thrombotic thrombocytopenic purpura seen in an eight month period, respiratory impairment was present. Respiratory dysfunction was characterized by tachypnea, hypoxemia nad infiltrates on chest roentgenogram. Five patients required mechanical ventilation. Two patients had cardiogenic pulmonary edema, but they remained hypoxemic despite treatment for pulmonary edema and maintenance of normal pulmonary capillary wedge pressure for more than 36 hours. Four patients died and autopsies revealed pulmonary edema, hemorrhage and hyaline thrombi. Pathologic examination of the heart also showed hyaline thrombi. Information from out patients with thrombotic thrombocytopenic purpura implicates respiratory dysfunction as a component of this disease as well as the classically described pentad. Cardiogenic and noncardiogenic pulmonary edema and possibly bleeding into the lung contributed to pulmonary impairment.

Noninvasive determination of glomerular filtration rate using x-ray fluorescence.

Accurate glomerular filtration rates (GFR) can be calculated based on the infusion of small amounts of nonradioactive iothalamate and collection of plasma samples for assay by x-ray fluorescence. This innovation permits frequent clearance determinations in patients without the hazard of repeated radiation exposure and without the necessity of catheterization of the bladder for urine samples. Thus, the technique becomes feasible in children, transplant patients, and other needing accurate and frequent GFR determinations.

Intestinal concentration of 99mTc-pertechnetate into isolated loops of rat bowel.

In scanning patients for Meckel's diverticulum, the colon occasionally visualizes more rapidly than would be expected simply from gastric secretion and intestinal transit. To gain a better understanding of the intestinal physiology of pertechnetate and thereby to make a more intelligent interpretation of abdominal scans, segments of the gastrointestinal tract of Sprague-Dawley rats were isolated by transection between double ligations. After abdominal closure, the animals received an intravenous injection of 99mTcO4 and were killed at 30, 45, or 150 min after injection. Technetium concentrations in the stomach, colon, and appendiceal contents increased significantly with time after dosing, and after 30 min technetium could be clearly imaged in the stomach, upper small intestine, appendix, and colon. These results suggest that technetium is actively secreted by the intestinal mucosa. Additionally, the results indicate caution in the interpretation of scans in patients with suspected Meckel's diverticulum since, in the rat and probably in the human, significant amounts of technetium can accumulate in the gut apart from gastric secretion and intestinal transit.

Pathology and Development of the Grasshopper Inclusion Body Virus in Melanoplus sanguinipes.

Grasshoppers, Melanoplus sanguinipes (F.), infected with the grasshopper inclusion body virus (GIBV) showed a general torpor, took longer to develop, and had abnormally high rates of mortality. Infection was found only in the fat body, and developing viruses and inclusion bodies were observed in the nuclei and cytoplasm of infected cells. Although the size of the inclusion bodies in cells varied at different stages of infection, the inclusion bodies appeared to grow during the infection. Electron microscopic investigations of viral replication showed that at about 8 days after inoculation presumptive viral particles had developed as buds or protrusions from precursor granular masses; thereafter, these particles underwent internal differentiation and were incorporated into developing inclusion bodies. The GIBV was similar to insect viruses in the genus Vagoiavirus Weiser and to pox viruses, particularly vaccinia.