Therapy for attention-deficit hyperactivity disorder.
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Adult↗
Biomedical subjects
S A Lofton
Publications and source records attributed to S A Lofton.
Influence of demographics and profitability on physician selection of family practice procedures.
BACKGROUND: Family physicians must make complex decisions regarding which procedures to learn in training and which to perform in practice. Factors that influence these decisions include community needs, the potential profitability of a procedure, and the desires and skills of the individual physician. METHODS: To further clarify some of these influences, we surveyed members of the Wisconsin Academy of Family Physicians. The survey instrument included questions about 27 different procedures, including the perceived profitability of the procedure, which procedures they had discontinued, and which they planned to learn. RESULTS: More than 40% of family physicians reported doing skin surgery, flexible sigmoidoscopy, nonstress obstetrical testing, breast-cyst aspiration, multiple joint arthrocentesis, and Norplant insertion, whereas fewer than 6% perform colonoscopy, esophagogastroduodenoscopy, and nasolaryngoscopy. Fifty-seven percent of physicians had discontinued at least one procedure, and 34% planned to learn one or more procedures. Being younger, male, and practicing in smaller communities correlated with performing a greater number of procedures (P < .001), but female physicians performed more gynecologic procedures (P < .05). There was a statistically significant correlation (r = -.478, P < .05) between perceived low profitability of a procedure and family physicians discontinuing a learned procedure, and a marginal correlation between perceived profitability and planning to learn a procedure (r = .338, P < .1). CONCLUSIONS: Family physicians in Wisconsin vary greatly in the number and types of procedures performed. Community size, sex, and age are important variables associated with the number and type of procedures performed. The performance of procedures is dynamic: physicians both discontinue learned procedures and learn new procedures. The profitability of the procedure influences the learning and discontinuation of procedures.
Adult↗
Differential diagnosis of genitourinary tumors using monoclonal antibodies to intermediate filament proteins.
Definitive diagnosis of poorly differentiated and metastatic neoplasms may be impossible using conventional histologic criteria. Recent developments in cell biology and immunology now enable us to answer such difficult diagnostic problems. Several varieties of structural proteins can be identified in malignant cells using monoclonal antibodies. The composition of these proteins can yield information regarding the origin of a neoplasm. Intermediate filaments are one such family of structural proteins. By characterization of these proteins, using a panel of monoclonal antibodies, poorly differentiated tumors may be definitively classified as carcinomas, sarcomas, lymphomas, or neural tumors. This approach to tumor diagnosis is now applicable to difficult problems in clinical urology.
Adenocarcinoma↗
Plasticity of medial gastrocnemius motor units following cordotomy in the cat.
Experiments were performed in adult cats to determine the effects of lumbar cordotomy on synaptic potentials, motoneuron membrane electrical properties, muscle-unit contractile properties, and whole-muscle histochemical properties of a heterogeneous skeletal muscle. Medial gastrocnemius (MG) motor units were examined 1 wk to 7 mo following complete transection of the lumbar spinal cord (cordotomy). Motor units were classified on the basis of their contractile properties as type FF, FI, FR, or S (8, 68). Muscle fibers were classified as type FG, FOG, or SO on the basis of histochemical staining (59). Motoneuron electrical properties (axonal conduction velocity, action-potential amplitude, rheobase, input resistance, afterhyperpolarization), group I EPSPs, and muscle-unit contractile properties (unpotentiated and potentiated twitch, unfused and fused tetanus, fatigability) were measured. Reduced numbers of type FR motor units and increased numbers of types FI + FF motor units were found in electrophysiological experiments 2 wk to 7 mo following cordotomy. Corroborative data were obtained from histochemical studies of the same MG muscles. Electrical properties of the motoneurons of each motor-unit type were normal following cordotomy. The close correspondence between motoneuron electrical properties and muscle-unit contractile properties found in normal MG muscle (68) was preserved following cordotomy. Contractile strength of muscle units of all types was severely reduced following cordotomy; partial recovery occurred 4-7 mo following cordotomy. Cross-sectional area of muscle fibers was reduced at all times investigated (2 wk to 7 mo). In three cats, homonymous group Ia single-fiber-motoneuron EPSPs were studied 1 or 2 mo following cordotomy at spinal level L4-5 or L5. EPSP amplitude and afferent-to-motoneuron projection frequency were normal. In 12 other cats, composite heteronymous group I EPSPs were studied 2 wk to 7 mo following cordotomy at various levels. Amplitude of these EPSPs was increased, dependent upon level of cordotomy and postoperative time. Hypotheses concerning the influence of motoneurons on muscle, and of muscle on motoneurons, are presented as possible mechanisms whereby the close relation between motoneuron electrical and muscle-unit contractile properties is preserved in the face of redistributed motor-unit populations.
Afferent Pathways↗
Monosynaptic projections of individual spindle group II afferents to type-identified medial gastrocnemius motoneurons in the cat.
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Animals↗
Influence of triiodothyronine on the amino acid uptake of brain and spinal cord in normal and spinal hemisected adult rats.
The thyroid hormones triiodothyronine (T3) and L-thyroxine appear to enhance regeneration in the peripheral and central nervous system (CNS). The following experiments examine possible metabolic substrates for the action of T3 on the adult rat CNS after spinal hemisection. The protein incorporation of (3H)lysine after a left spinal hemisection (T2) or control operations was examined 1, 3, 7, and 14 days postoperation. Triiodothyronine (1 microgram/kg body weight in a bicarbonate buffer) was injected daily for the postoperation or equivalent time period. One hour prior to decapitation, animals were given a subcutaneous injection of 200 microCi of (3H)lysine. Samples of brain and spinal cord were dissolved, and the radioactivity of acid-precipitable protein and acid-soluble fractions were determined by scintillation counting. T3 treatment influenced the general levels of incorporation of all treated groups over all days postoperation. Specific effects were observed in spinal hemisected T3-treated animals. A significant hemispheric (P less than 0.05) asymmetry was present at 3 days postoperation with the right somatomotor cortex higher in protein radioactivity than the left. In spinal cord, the area of the lesion and areas just caudal to the lesion were higher in (3H)lysine incorporation in T3-treated rats relative to controls. T3 effects appear to involve an increased sensitivity of the cells of the injured nervous system to the hormone.
Amino Acids↗
Ketoacids and the insulin receptor.
The binding of insulin to a specific receptor on IM-9-cultured human lymphocytes was studied in vitro under conditions simulating diabetic ketoacidosis. Compared with control incubations at pH 7.4, binding was reduced by 19 per cent at pH 7.1 and by 48 per cent at pH 6.8. Addition of beta-hydroxybutyrate, at concentrations similar to those seen clinically, "restored" insulin binding toward normal. We suggest that, by counteracting the effects of acidosis, ketoacids themselves maintain normal insulin-receptor binding in diabetic ketoacidosis. These data also illustrate that small molecules, present in vivo, can significantly alter the interactions between a hormone and its receptor in vitro.
Acetoacetates↗