Hypomagnesaemic tetany associated with repeated courses of intravenous tobramycin in a patient with cystic fibrosis.
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Biomedical subjects
Publications and source records attributed to J P Adams.
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In a study of 57 older parent caregivers of adult children with mental retardation, more than half had not planned for their child's future care. Income, race, child's gender and level of adaptive behavior, and degree of parental interaction with relatives and friends were significantly related to future care-planning activity.
The effect of calcium chloride (CaCl2) on the activated partial thromboplastin time (aPTT) of heparinized plasma was studied. The aPTT ratio (heparinized plasma:control plasma) increased as the CaCl2 concentration to recalcify the plasma was increased from 15 to 35 mmol/L CaCl2. Platelet-poor plasma from patients receiving intravenous heparin, and in vitro heparinized plasmas from either coumarinized patients or plasma depleted of the vitamin K-dependent factors, displayed the calcium-dependent increase in the aPTT ratio. The magnitude of the calcium-dependent change in the aPTT ratio was similar for the three partial thromboplastins studied. Heparinized blood collected in 3.2% and 3.8% citrate demonstrated the calcium-dependent increase in the aPTT ratio. The authors have also studied the effect of the divalent cations (Ca+2, Mg+2, Zn+2, and Sr+2) on the anti-Factor Xa activity of heparin to determine whether the calcium-dependent increase in the aPTT was due to an increase in the anti-Factor Xa activity. The anti-Factor Xa activity of heparin was measured using chromogenic substrate S-2251, purified Factor Xa, and excess antithrombin III. The anti-Factor Xa activity of heparinized plasma increased 2.4-2.8-fold as the divalent cation concentration was increased from 0-5 mmol/L. Similar results were obtained using purified bovine Factor Xa, antithrombin III, and heparin in the absence of plasma. These results suggest that divalent cations play an important role in modulating heparin's anticoagulant activity in vitro. In addition, the CaCl2 concentration used to recalcify plasma is an important variable that modifies heparin sensitivity of the aPTT. Furthermore, divalent cations play an important role in regulating the anti-Factor Xa activity of heparin in vitro.
A young healthy male, who had three consecutive episodes of postoperative hyperthermia was anaesthetized with special precautions to prevent malignant hyperthermia. Despite neuroleptic anaesthesia and dantrolene pretreatment, the patient experienced post-anaesthetic hyperthermia. The patient's clinical picture was almost identical to the symptoms experienced by two of his maternal relatives. All three experienced nausea, vomiting, muscle cramps and high fever which occurred between five to seven hours after general anaesthesia. The serum potassium (K) and creatinine phosphokinase (CPK) levels determined during the hyperthermic episode and on the next day were not elevated. On the basis of the patient's family history, his clinical picture, and his laboratory data, we speculate that this patient might have a form of malignant hyperthermia or a possible new variant.
A technique that uses laser light diffraction to measure muscle sarcomere length allows direct determination of optimal muscle length during tendon transfers. Forearm muscle sarcomere length with the hand in the position of function is 2.4, and muscle length corresponds directly to sarcomere length. We have used these observations to restore optimal muscle length during tendon transfers. Standard high radial nerve tendon transfers in six fresh cadaver forearms demonstrated the efficacy of the laser diffraction method in accurately measuring sarcomere length. In two clinical trials with the laser, standard high radial nerve palsy tendon transfers were performed. In each case the clinical tendency was to overpull the muscle during the transfer. With the laser it was possible to identify excessive muscle stretch and restore optimal muscle length.
Rare earth filters are known to reduce radiation dose in radiological investigations. The present investigation used Er and Sm filters that were selected because of their chemical stability and ability to withstand prolonged exposure to the atmosphere. They were used in a comparison with a conventional aluminium filter in a range of paediatric radiological procedures. Introduction of the filters instead of the conventional filter, resulted in a dose reduction of up to twofold with no discernible deterioration in image quality.
Numerous case reports have described idiopathic hypertrophy of the skin on the dorsum of the hands. Many different and confusing names have been assigned to these conditions. A case report of a patient with pachydermodactyly is presented, with a discussion of the literature, in an effort to clarify the identification, treatment, and nomenclature of idiopathic hyperkeratosis and acanthosis of the dorsum of the hands.
A randomized prospective study of 265 patients with hand lacerations was carried out to define the role of prophylactic antibiotics in the management of simple, sutured wounds of the hand. Two hundred sixty-five patients were followed up until suture removal or satisfactory wound healing. There were a total of three infections (1.1%). There was no noticeable differences in the incidence of infection in the antibiotic and placebo treatment groups. It is concluded that prophylactic antibiotics are an unnecessary adjunct in the treatment of simple lacerations of the hand and no replacement for meticulous wound management.
The palmar fascial tissues of more than 400 patients with Dupuytren's disease were studied biochemically and compared with normal tissue obtained from more than 100 patients who were undergoing hand surgery for other reasons. No alterations of the molecular structure or the state of macromolecular aggregation of the collagen in Dupuytren's disease were detected by wide or low-angle x-ray diffraction studies or by transmission electron microscopy. Major biochemical changes in the palmar fascia affected by Dupuytren's disease included increased collagen and hexosamine contents and the presence of galactosamine in the most severely involved tissue. Type-III collagen, which is virtually absent from normal adult palmar fascia, was abundant in the tissue of patients with Dupuytren's disease. Post-translational modifications included a very elevated hydroxylysine content, an increase in the total number of reducible cross-links, and the appearance of hydroxylysinohydroxynorleucine (virtually absent from normal palmar fascia) as the major reducible cross-link. Even palmar fascia from patients with Dupuytren's disease that appeared grossly and histologically normal showed the same biochemical changes, albeit to a lesser extent. All of these biochemical changes are similar to those that occur during the active stages of connective-tissue wound repair. This includes the rapid synthesis and turnover of collagen which leads to newly synthesized, immature collagen being more abundant in the involved tissue than in normal tissue. There is no evidence that the gross, macroscopic contracture of the palmar fascia in Dupuytren's disease is due to shortening, plication, or contraction of the collagen fibrils or fibers present in the tissue at the onset of the disease or synthesized during its development. Instead, we propose that the gross contracture (shortening) of the palmar fascia in Dupuytren's disease is due to an active cellular process that progressively draws the distal extremities of the affected tissue closer together at the same time that the original tissue is being replaced. The result of these two processes is simply a shorter, smaller piece of tissue fabric containing collagen molecules, fibrils, and fibers of normal length and organization, but with pretranslational and posttranslational modifications similar to those observed in collagens during the active stages of connective-tissue repair in general.
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The subclasses of platelet-associated IgG were measured on the platelets of patients with immune thrombocytopenic purpura (ITP) by modification of the antiglobulin consumption test. All subclasses were found. In most patients, one subclass was predominant; this was usually IgG1. The platelet-associated IgG in normal donors is predominantly IgG1 and IgG2.
Extracts of the membranes of normal red cells and red cells from all subpopulations of paroxysmal nocturnal (PNH) red cells inhibited antibody-mediated complement activation. These extracts were shown to accelerate decay of the complement complex. C42, and the relative amount of inhibitory activity was similar in normal and PNH membranes. Inhibitors derived from normal red cells markedly decreased lysis of both PNH and normal cells when antibody was present in excess and complement was limiting. These same inhibitors decreased PNH cell lysis to a much lesser degree when complement was activated with cobra venom or acidified serum. The susceptibility of the PNH cell to complement lysis because of an increased fixation of C3 to its membrane is not due to a difference in membrane-associated accelerator of the decay of the C42 complex.
The amount of lysis effected by cold agglutinins is directly related to the ability of the antibody to initiate complement activation. This ability is modified by the concentration of antibody, its thermal amplitude (the highest temperature at which the antibody will react with the cell), the degree to which antibody fixation is modified by the presence of complement components (particularly C3) on the membrane, and the degree to which antibody, once fixed, is able to fix the components of complement. In vitro measurement of these factors correlates with the rate of hemolysis in vivo.
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Paroxysmal nocturnal hemoglobinuria (PNH) cells are characterized by an abnormal membrane which interacts abnormally with normal serum complement. These abnormal reactions occur at two levels of the sequence: 1) All abnormal PNH cells fix more C3 than normal cells for a given activation of complement; 2) PNH III cells are more readily lysed by a given number of assembled terminal complexes. The nature of the lesion yielding these abnormal reactions is not known.
The functional, biochemical, and histological changes in a severed median nerve, 9 months after epineurial repair, were studied in 14 monkeys. In seven the mesoneurium had been stripped 5 cm proximal and 5 cm distal to the site of repair, and in seven the nerve had been stripped only over a 0.5 cm area, just enough to allow repair. In the first group the mean muscular strength in the abductor pollicis brevis was 197 gm, as compared to 257 gm in the second group. The amount of collagen in the perineurium was 57 microgram/mg, as compared to 43 microgram/mg, and the incidence of the h-l-h-nl cross-link was 16% to 21%, as compared to 9% to 11%. If the regeneration of the lacerated nerve was compromised by the deposition of collagen resulting from mobilization of the distal segment, as suggested by the decrease in the strength of the abductor pollicis brevis muscle, then any mobilization of a nerve necessary to obtain a sutured junction with minimum tension should be limited to the proximal segment.