Vitamin D metabolite concentrations in vitamin D deficiency. Are calcitriol levels normal

The levels of vitamin D metabolites were measured in three children with a decreased dietary intake of calcium and vitamin D and sun exposure. All three children had hypocalcemia, hypophosphatemia, and elevated alkaline phosphatase activities. Two children had rickets, aminoaciduria, and elevated immunoreactive parathyroid hormone (iPTH) concentrations. The concentrations of vitamins D2 and D3, 25-hydroxyvitamins D2 and D3 (25-OH-D2 and 25-OH-D3), and 24,25-dihydroxyvitamin D (24,25-[OH]2D) were reduced. Nonetheless, the levels of calcitriol (1,25-[OH]2D) were normal. The combination of hypocalcemia, hypophosphatemia, and increased iPTH concentrations should result in supranormal calcitriol concentrations. Moreover, the ratio of PTH to calcitriol is significantly higher than in normal subjects. Accordingly, in patients with vitamin D deficiency and "normal" calcitriol values, the synthesis of this compound may be reduced. The evaluation of vitamin D deficiency should include the measurement of all metabolites.

Observations on the structure of the eumelanosome matrix in melanosomes of the chick retinal pigment epithelium

Eumelanosomes from the developing chick pigment epithelium have been isolated, solubilized, and the residue collected. Examination of this material in the electron microscope provides evidence for new structural entities in the eumelanosome and information on the organization of the melanosome. This evidence suggests that there are (1) 190-A fibers arranged in a zigzag fashion, surrounding 240-A-diameter electron-lucent spaces and (2) an internal gridwork enclosing 40-50-A diameter spaces. These two structures are probably alternately layered and "rolled-up".

Civil commitment as a "street-level" bureaucracy: case-load, professionalization and administration

This article applies street-level bureaucracy theories to "coping" patterns of behavior that developed in an involuntary commitment system. Daily procedures and routines of five Nebraska county boards of mental health and the attitudes of their members were studied. The results showed that the urban, high case-load, professionally-oriented board informally modified statutory procedures significantly to reduce face-to-face client contact, limit the scope of its decisions, and displace responsibility for the most ambiguous decisions to the treatment facility and board psychiatrist. Rural, low case-load, less professionally-specialized boards also modified the statutory procedures, but conducted the commitment process in a far more ambiguous, open-ended, and tense system with substantial face-to-face client contact. Both urban and rural boards had multifaceted role definitions; rural boards, however, had a more open-ended perception of their functions, and attempted more actively to modify antisocial behavior and redirect board subjects to sources of social counseling. Therefore, understanding street-level "coping" behavior in an actual commitment context is important to develop realistic changes in civil commitment systems and to preclude informal procedures that reduce a commitment system's effectiveness or undermine a proposed patient' s rights.

Envenoming by Cerastes viper - a report of two cases

Two cases of envenoming by Cerastes vipera are described Both were in snake collectors who were accidentally bitten on the finger while handling the snake. In both cases, local signs included a haemorrhagic bulla with fang marks, swelling and tenderness. These signs were mild in one case and moderately severe in the other, necessitating fasciotomy. No systemic signs were observed. Some coagulation abnormalities were found in both cases. In one, prolonged bleeding from the wound and a shortened euglobulin lysis time may suggest activation of the fibrinolytic mechanism. In the other, prolongation of prothrombin time occurred with no haemorrhagic diathesis. Treatment included fasciotomy in one case and elevation of the affected part and antibiotics in the other. It appears that the clinical course of this snakebite is relatively benign.

Acute lymphoblastic leukemia. Association with vasopressin-responsive diabetes insipidus

A rare case of acute lymphoblastic leukemia presenting with vasopressin-responsive diabetes insipidus (DI) is reported. The patient presented with polydypsia and polyuria of 9 L/day. Findings from special investigations of the CNS, including brain scan, computerized tomographic scan, EEG, and lumbar puncture were within normal limits. The patient's condition improved substantially after receiving vasopressin injections and later chlorpropamide. The incidence and underlying mechanism of this rare complication of acute leukemia are reviewed, and the response of DI to chlorpropamide is discussed briefly. In this patient it is presumed that the DI was caused by leukemic infiltration of the supraopticohypophyseal tract, posterior pituitary, or hypothalamus.

Characteristics of patients with chronic pain

We describe the characteristics which patients with chronic pain ascribe to themselves and present some of the data we have gathered in the areas of demographics, economic and family problems, difficulty in rehabilitation, and the failure of treatment methods such as surgery and medications to provide relief. We compared the responses of men and women and found significant differences in sexual difficulties and pain relief from nerve blocks.

Clindamycin unresponsive anaerobic osteomyelitis treated with oral metronidazole

A diabetic patient with peripheral neuropathy and a foot ulcer developed osteomyelitis of the foot. Antibiotic therapy of the aerobes isolated from the ulcer resulted in no clinical improvement. Intravenous clindamycin therapy of the anaerobe isolated (Bacteroides fragilis) was associated with an incomplete and temporary response, but there was a dramatic response to oral metronidazole with healing of the ulcer and osteomyelitis. One year later there were no signs of recurrence.

Are microcomputers appropriate for your practice?

The overly simplistic view of the process of automation widely presented to physicians needs to be counterbalanced. Computers are becoming cheaper, easier to program, and simpler to operate. However, the physician must be aware of the gap between personal computing and serious use of computers in his practice. To bridge this gap, the physician must analyze his needs to identify appropriate applications to automate, plan the implementation of these applications, and choose the necessary hardware and software resources. To do so it may be valuable for him to seek the help of an expert. Although the physician can certainly perform the necessary tasks, he should be aware that to perform them efficiently there are a number of aspects he should seriously consider.

Use of an interactive teaching program to teach medical workers, about MUMPS programming

The MUMPS computer language is widely and increasingly used for medical applications. It is useful for medical students and others in the medical environment to have an understanding of such languages that can help them perform their jobs well. The author is therefore making available an interactive teaching program to instruct such people in the MUMPS computer language. Use of the teaching program is reported for 19 novice MUMPS programmers and compared with results for two experienced programmers. Free-text comments by the novices emphasize areas in which they had difficulty. There is a considerable variation in the mean time taken by the novices to answer the questions, and in the number of questions repeated because of erroneous answers. Most novices found the teaching program very helpful. A copy of the Standard MUMPS teaching program and the QUEST driver on which it is based has been sent to 24 institutions, including six in Europe and one in Japan, for further use.

History and future of the MUMPS in medical computing

MUMPS is an integrated language and operating system. It was originally developed in the mid 60s, primarily for the interactive manipulation of text-like, hierachical data found so pervasively in medicine. This paper traces the growth in use of MUMPS. Some of the many medical application for which MUMPS is used are discussed, as are the achievements and goals of the MUMPS Users' Group, particularly in facilitating application transfer. The influence of federal funding upon the growth and use of MUMPS is noted. Of particular importance is the federal support of the MUMPS Development Committee in the standardization of MUMPS, and the MUMPS User's Group in promoting MUMPS information and application exchange.

Physician utilization of medical records: preliminary determinations

A study is reported of the ways in which 26 physicians, mostly internists, use the medical record. It was found that the items of greatest importance to the physicians, from the viewpoints of frequency of usage and of occasional interruption of the physician-patient transaction by being absent, were lab-test results, X-ray data, patient history, and previous treatments. The most common general problems cited uith the medical record were incompleteness (named by 38 per cent of the physicians), illegibility (27 per cent), and poor organization of the record (19 per cent).

The acceptability of computer applications to group practices

Of the 72 identified group practices in a midwest urban environment, 39 were found to use computers. The practices had been influenced strongly by vendors in their selection of an automated system or service, and had usually spent less than a work-month analyzing their needs and reviewing alternate ways in which those needs could be met. Ninety-seven percent of the practices had some financial applications and 64% had administrative applications, but only 2.5% had medical applications. For half the practices at least 2 months elapsed from the time the automated applications were put into operation until they were considered to be integrated into the office routine. Advantages experienced by at least a third of the practices using computers were that the work was done faster, information was more readily available, and costs were reduced. The most common disadvantage was inflexibility. Most (89%) of the practices believed that automation was preferable to their previous manual system.

Within-subject control designs and voluntary bidirectional control of cardiac rate: methodological comparison between pre-experiment and pretrial baselines

The purpose of this study was to compare two methods of analyzing the effects of exteroceptive feedback training on the voluntary bidirectional control of human cardiac rate with the use of a within-subject control design. In this design heart rate (HR) during an experimental period (increase or decrease) is compared with that recorded during some other control period, generally a baseline "rest" period. Ten male undergraduates were instructed to control HR and given visual feedback of heart activity. Trials on which Ss were to raise and to lower HR were both given in a single training session. The data were analyzed in two ways: (a) cardiac rate during HR control periods was compared to an initial pre-experimetn baseline; (b) cardiac rate during HR control periods was compared to a running pretrial baseline. The results support the argument that the former procedure fails to take account of habituating levels of cardiac rate and favors finding large magnitude decreases in HR but small increases, whereas the latter procedure favors finding large magnitude increases but small decreases. It is suggested that magnitude of directional control will be artifactual when initial values are used to assess change. Contaminating influences on the running pretrial baseline were also discussed.

Reconstruction of the cardiac valves with autologous tissue

A rather long and extensive experience with tissue reconstruction in patients with mitral valve disease, and a much less extensive one with oartic lesions, has convinced us of the superiority of the presented techniques of reconstruction, and of the preferability of fascia lata over all other tissues so far tried for this purpose. Despite an early increment of shrinkage of the order of about 30% of each linear measurement, late studies of fascia lata removed from reconstructed valves after several years (over five) indicate no loss of cellularity and no measurable loss of tissue strength or flexibility. Late calcification was not observed in any of our baboons, although it appears to be a consistent development in dogs. It has been seen in only one patient (after four years) to date. It is now believed that we can offer prolonged clinical benefit approaching actural "cure" to many of the younger patients who otherwise would have no recourse but to prosthetic palliation. It is true that recently Willen, Dubiel and Johansson (50, 51), Gersbach and Wegmann (52), and Senning and Rothlin (53) have demonstrated that repetitive deposits of fibrin upon the surfaces of fascia lata implanted within the cardiovascular chambers lead to progressive encapsulation with organizing connective tissue (scar). At some time period following surgery, closer to 10 years than to 5, degeneration of the fascia takes place, presumably due to "strangulation" by the organized exudate which interrupts the "normal" mechanism of its nutrition which is based upon diffusion from the flowing blood. The recent contributions of Sullivan, Harken and Gorlin (54), Weily and Genton (55), and Harker and Slicter (56) to our understanding of the role of the platelets in initiating such fibrinous deposition now provide us with a way to prevent such late degeneration of valves made of fascia lata. The regular administration of platelet dispersing agents (aspirin, Persantin, or inderol) in ordinary therapeutic dosage would seem to be completely protective. Undoubtedly, anticoagulant therapy would be equally effective. However, the permanent maintenance of a proper level of "anti-coagulation" such as is usually deemed necessary following implantation of a prosthetic heart valve is a heavy psychological and biological burden for a patient to bear. Many such individuals live precariously between the risks of thromboembolism and the risks of hemorrhage. Thromboembolism really only represents a farther point along the spectrum of the readiness of fibrin accumulation following initial platelet aggregation and deposition. Since frank thromboembolism appears "never" to follow intracardiac implantation of fascia lata, it would seem that platelet dispersive therapy sould suffice in such cases.

The human magnetoencephalogram: some EEG and related correlations

Simultaneous magnetoencephalographic (MEG) and electroencephalographic (EEG) data were recorded from six normal adult subjects. MEG signal strength and EEG voltage level appear to be linearly correlated. Spectral analysis suggested that the MEG and EEG data were produced by similar but non-identical generator systems. A vertex region magnetic averaged evoked response to flash was recorded in one (of four) subjects, consisting of a waveform similar to but out of phase with the simultaneous EEG averaged evoked response, such that cortical negativity was correlated with a magnetic field directed into the scalp. Eye movement artifact, which can seriously compromise EEG recordings, does not appear to be a major problem in MEG recordings.

Language and speech correlates of anatomically verified lesions in thalamic surgery for parkinsonism

The brains of 27 deceased parkinsonian patients who had undergone stereotaxic thalamic surgery were examined anatomically to define the exact location of the surgical lesion in each case. A correlative study was then carried out between the site of these lesions and any language or speech deficits which might have resulted from the thalamic surgery. The following conclusions were drawn:

Effects of conditioned reinforcement frequency in an intermittent free-feeding situation

Key-pecking intermittently produced a set of brief exteroceptive stimulus changes under two-component multiple schedules of conditioned reinforcement. Throughout the study, free access to grain was concurrently provided on an intermittent basis via a variable-interval tape. Free food presentations scheduled by the tape were delivered if no peck had been emitted for 6 sec, and the brief stimulus changes produced by responding under the multiple schedules were those which accompanied food presentation. The second component of each multiple schedule was always associated with a 1-min, variable-interval schedule of conditioned reinforcement. The schedule associated with the first component was systematically varied and conditioned reinforcement was either absent (extinction) or programmed on a 1-, 3-, 6-, or 12-min variable-interval schedule. Under these conditions, rate of responding in the manipulated component decreased monotonically with a decrease in the frequency of conditioned reinforcement. In addition, contrast effects were often obtained in the constant, second component. These results are similar to those obtained with similar multiple schedules of primary reinforcement.

Panel for Stimulus Control over Toggle-Switch Behavior in Technicians

This note describes a device which controls toggle-positioning behavior in technicians. Its application has eliminated toggle-positioning errors and superseded the daily verbal instructions previously employed. It can be applied to the reduction of technician errors in any situation in which a given set of equipment is used repeatedly in different ways over short periods of time.

The functional and surgical anatomy of the heart

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Second-order avoidance behavior in monkeys

Two monkeys were trained on a three-component multiple schedule using discrete trials. In one component (food), a response terminated a red stimulus and produced food and S(Delta). In the second component (avoidance), a response terminated a green stimulus and avoided shock. In the third component (optional), a response terminated a blue stimulus and produced S(Delta). The consequence of not responding in the blue stimulus, however, was the production of either a food or an avoidance trial. Manipulation of these consequences showed that when food trials were available only a small percent of the time after optional trials, the subjects tended not to respond in the blue, even though this led to an increase in the total number of avoidance trials per day. If only avoidance trials followed as a consequence of not responding in the optional component, the animals terminated the blue stimulus and avoided the avoidance trials. Throughout the experiment both subjects maintained consistently low shock rates (about 10 per day) and these were not affected by the various manipulations. The data suggest that a stimulus associated with avoidance can be a conditioned aversive stimulus and will maintain a more remote avoidance response under certain conditions.

Sustaining behavior with conditioned reinforcement as the only response-produced consequence

Food was intermittently presented to pigeons on a response-independent basis. Concurrently, pecking at a key was intermittently reinforced with the presentation of stimuli which accompanied the food presentation, but not the food. Under these conditions, key-pecking was maintained indefinitely at moderate rates and control procedures demonstrated that the results could only be accounted for on the basis of conditioned reinforcement.

The effects of a pre-time-out stimulus on matching-to-sample of humans

In each of two experiments human subjects were intermittently reinforced with money on a fixed-ratio schedule for emitting correct matching responses. A pre-time-out stimulus which signaled removal of positive reinforcement was periodically superimposed. In the first experiment the superimposed pre-time-out stimulus was paired with a 1-min or 4-min response-independent time out. In the second experiment the pre-time-out stimulus was paired with a 1-min or 4-min time out contingent on the incorrect responses. The pre-time-out stimulus did not markedly influence performance when the time out was response independent. In contrast, the pre-time-out stimulus markedly suppressed incorrect responding when the time out was contingent on the incorrect responses. When duration of this time-out was increased from 1-min to 4-min, suppression of incorrect responding increased and correct responding was suppressed. Therefore, behavioral suppression by a pre-time-out stimulus was obtained only when the signaled aversive event-time out-was response produced. In this case, suppression was influenced by time-out duration.