An audit of the preoperative investigation of surgical patients

The pattern of preoperative investigation was audited in 256 patients entering hospital for elective surgery over a 12-week period. During the initial 6 weeks (phase one), no guidance was given to the house surgeons and the investigations were assessed as being 'indicated' or 'not indicated' according to preset criteria. A total of 272 investigations was performed on 117 patients. Minor modifications were made to the criteria. At the beginning of the second 6-week period (phase two), the modified criteria were distributed to the house surgeons as a guide to preoperative investigation. During this time 308 investigations were performed on 136 patients. The number of investigations (excluding ECGs) that were available at the time of surgery rose significantly (P < 0.001) from 66% in phase one to 81% in phase two. The percentage of investigations deemed to have been indicated rose significantly (P < 0.001) from 53% in the first phase to 90% in the second phase. It is calculated that in practice 94% of the maximum possible savings of 7080 pounds could be achieved over the course of 1 year by implementing these criteria for preoperative investigations.

An evaluation of rapid exchange and simultaneous grip tests

The usefulness of the rapid exchange grip test and a modification of this test, the rapid simultaneous grip test, in detecting submaximal grip efforts was evaluated. Uninjured subjects giving maximal or submaximal grip efforts were tested at grip rates of 80 and 100 repetitions per minute. Rapid exchange grip at 80 repetitions per minute yielded a sensitivity of 86% and a specificity of 97%. Rapid simultaneous grip at 80 repetitions per minute yielded a sensitivity of 81% and a specificity of 93%. Poorer sensitivities and specificities resulted when a clinical population of patients was tested. Patients who were not giving maximal efforts tended not to comply with the test protocol. The rapid exchange and rapid simultaneous grip tests do assist in detecting submaximal grip efforts; limits to these tests are emphasized.

Phase I pharmacokinetics study of high-dose fotemustine and its metabolite 2-chloroethanol in patients with high-grade gliomas

The pharmacokinetics of high-dose fotemustine followed by autologous bone-marrow transplantation during a phase I-II clinical trial in 24 patients with glioblastoma or astrocytoma (grade III-IV) was investigated. Plasma levels of fotemustine were determined by high-performance liquid chromatography (HPLC) and UV detection. The metabolite, 2-chloroethanol, was simultaneously followed in six patients by gag liquid chromatography and electron capture detection (GLC-ECD) assay. The drug was given as a 1-h infusion on 2 consecutive days. In all, 40 pharmacokinetic determinations of fotemustine were made at dose levels ranging from 2 x 300 to 2 x 500 mg/m2. Plasma drug elimination was best described by a bi-exponential model, with short distribution and elimination half-lives of 4.15 +/- 2.57 and 28.8 +/- 12.1 min being observed, respectively. No significant difference in half-lives or clearance was seen between the first and the second administration. During dose escalation, the mean area under the concentrationtime curve (AUC) increased from 5.96 +/- 2.89 to 12.22 +/- 3.95 mg l-1 h. Drug clearance was independent of the dose given and equal to 109 +/- 65 l/h, indicating no possible saturation of metabolism and elimination mechanisms at these high-dose levels. The metabolite 2-chloroethanol appeared very early in plasma samples. Its elimination was rapid and rate-limited by the kinetics of the parent compound, giving the same apparent terminal half-life. A close relationship between AUC and C45 values was evidenced (r = 0.890). Associated with the stability of fotemustine kinetic parameters, this could be used in future studies for individual dose adjustment, particularly for high-dose fractionated regimens.

Three-dimensional visualization of data on human anatomy: diagnosis and surgical planning

A system is described which produces displays of anatomical surfaces from sets of X-ray computed tomography (CT), magnetic resonance imaging (MRI) and ultrasonographic scans (US). The displays are created to show the three-dimensional character of the internal and external anatomy. The images may be manipulated on the screen to simulate dissection of the three-dimensional object they represent. Thus it is possible to increase the diagnostic value of the original data and to plan surgery by simulation. To allow long-term studies on the human face for surgical planning and assessment a non-hazardous optical scanning system has been devised. The display system also produces data to drive a numerically controlled milling machine for the production of models, prostheses and implants.

Three-dimensional CT imaging of the wrist. A practical system

Three-dimensional computerized tomography provides a new approach to radiological imaging. Raw data from sequential two-dimensional scans have been reconstructed as a three-dimensional model of the carpal area using the Medical Graphics and Imaging Workstation. This study demonstrates the anatomical accuracy and potential diagnostic qualities of a reconstruction of the carpus using this system. The advantages, pitfalls and suggested applications of this technique of carpal imaging are discussed. Three-dimensional imaging is shown to provide a great deal of information which cannot be viewed on conventional radiographs or CT images.

The M1 subunit of rat liver ribonucleotide reductase appears to be modified by ubiquitination

Using a combination of immunoblotting, double immunoprecipitation, immunoglobulin-affinity chromatography, and isoelectrofocusing, we have been able to identify a group of proteins that display CDP-reductase activity and contain antigenic epitopes recognized by anti-ribonucleotide reductase M1 subunit and anti-ubiquitin antibodies. In the cytoplasm of rat liver cells, we could detect a total of five proteins with molecular masses of 92, 89, 56, 45, and 37 kilodaltons which reacted with the anti-M1 subunit serum. All of them, except the 89-kilodalton protein (the nascent unmodified M1), were also recognized by the anti-ubiquitin antibody. In normal liver cells, all of the apparently ubiquitinated species of the M1 protein were found in the cytoplasm, but not in the nuclear envelope associated pool of the enzyme. However, we did not detect ubiquitinated M1 protein fragments in the cytoplasm of Morris hepatoma 5123tc. The level of the apparently ubiquitinated fragments of the M1 subunit increased in parallel to the DNA-synthetic activity of normal liver cells, suggesting that ubiquitination plays a key role in the regulation of the activity of the enzyme during the cell cycle.

Inhaled histamine increases the rate of absorption of sodium cromoglycate from the lung

Since many factors may alter lung epithelial permeability (LEP) to water soluble molecules, the effect of histamine on the absorption and clearance of inhaled sodium cromoglycate was examined in seven mildly asthmatic patients with hyperresponsive airways and eight normal subjects. The subjects underwent histamine challenge to determine the provocative concentration of histamine required to reduce the forced expiratory volume in one second (FEV1) by 20% (PC20) from baseline. On two further visits they inhaled either saline placebo or histamine and 5 min later inhaled an aerosol containing sodium cromoglycate. Measurements of FEV1 were made and blood samples taken for analysis of plasma sodium cromoglycate concentration at intervals for 3 h. In the asthmatic group histamine inhalation led to a 24 +/- 4% reduction in FEV1 but had no effect on the normal subjects. When compared with inhaled saline, histamine increased the initial pulmonary absorption of SCG without influencing the total amount of drug absorbed in both asthmatics and normals. These observations suggest that the pharmacokinetics of inhaled sodium cromoglycate may be altered significantly by inflammatory mediators present at the site of drug absorption from the airways.

Exertion-induced heat exhaustion. An often overlooked diagnosis

Exertion-induced heat exhaustion is a potentially lethal condition. The earliest signs include unsteady gait and confusion. Recording of rectal temperature is essential. Skin colour, blood pressure and heart rate are not reliable diagnostic signs. The mainstays of therapy are rapid rehydration and cooling. Prompt diagnosis and rapid effective therapy will minimise the risk of death.

Guidewire catheter change in central venous catheter biofilm formation in a burn population

This study was designed to assess the risk of colonization and biofilm formation of central venous catheters left in situ for seven days vs those changed over a guidewire at three days and removed at seven days. Colonization was determined using scanning and transmission electron microscopy and compared to a special scraping/sonication culture method. Thirty-one catheters were examined, and no difference was found between catheters left in situ (9 of 16 colonized) and those changed over a guidewire (11 of 15 colonized). Colonization rates rose significantly from 4 of 15 catheters at the time of guidewire change to 11 of 15 at 7 days (p less than 0.001). Of the catheters defined as colonized by SEM, the special culture technique showed bacterial growth in only 35 percent, making a negative culture result of dubious value in ruling out catheter colonization. No beneficial effect of guidewire changes in reducing colonization could be demonstrated.

Autocrine/paracrine regulation of prolactin release from human decidual cells

Studies from this laboratory indicate that the synthesis and release of prolactin from human decidual cells are regulated by factors released by the placenta, decidua and fetal membranes. A 23.5 kD protein (decidual prolactin-releasing factor, PRL-RF) has been purified to homogeneity from human placental tissue and placental conditioned medium. The releasing factor stimulates an acute release of prolactin that occurs within the first few minutes of exposure and a prolonged release, secondary to new hormone synthesis, that begins about 6-8 hours later. In addition, the synthesis and release of decidual prolactin are stimulated by IGF-I, insulin and relaxin, each acting through distinct plasma membrane receptors. In contrast, the synthesis and release of decidual prolactin are inhibited by arachidonic acid, lipocortin I and a 35-45 kD decidual protein (prolactin-releasing inhibitory factor) that has been partially purified from decidual conditioned medium. Studies of the second messengers involved in the regulation of decidual prolactin release strongly suggest that decidual prolactin release may be mediated, at least in part, by activation of phosphoinositide metabolism and stimulation of adenylate cyclase. The demonstration that the synthesis and release of decidual prolactin are regulated by PRL-RF, IGF-I, insulin, relaxin, arachidonic acid, PRL-IF and lipocortin I strongly suggests that there is novel autocrine/paracrine feedback regulation between the placenta, fetal membranes, and decidua in the regulation of decidual prolactin.

A mathematical method for the comparison of three-dimensional changes in the facial surface

Many attempts have been made to measure and compare the changes in the facial surface brought about by facial reconstructive surgery. Three-dimensional (3-D) analyses have largely consisted of qualitative descriptions rather than a quantitative treatment of these changes. Until recently, the lack of availability of 3-D data for the face and head has limited the advancement of these techniques. However, with 3-D information readily available from a laser scanning system which we have constructed, a technique has been applied which describes mathematically the facial shape and changes occurring in the face in terms of fundamental surface types. The method is described and used to compare the faces of two patients (one a cleft palate patient and the other a long-face, Class II malocclusion patient) before and after surgery along with the clinical description of the surgery, the resulting facial changes, the actual surgery performed, and the predicted surgical expectation. A strong relationship is found between the surface type description and the clinical observations. The implications of the method for surgery, facial aesthetics, and other disciplines are discussed.

Regulation of the synthesis and release of decidual prolactin by placental and autocrine/paracrine factors

Human decidual tissue synthesizes and secretes a protein that is identical to pituitary prolactin in its chemical, biological and immunological properties. Nevertheless, the factors that regulate the synthesis and release of prolactin from the decidual tissues appear to be different to those regulating the synthesis and release of pituitary prolactin. Studies from our laboratory over the past few years indicate that the synthesis and release of decidual prolactin are regulated, at least in part, by factors released by placenta, fetal membranes and decidua. The placenta releases a 23.5 KMr protein [decidual prolactin-releasing factor (PRL-RF)] that stimulates a rapid release of prolactin within the first few minutes of exposure and a sustained, prolonged, increase in the synthesis and release of prolactin beginning 6-8 h after exposure. The acute release of prolactin in response to PRL-RF is inhibited by decidual prolactin release-inhibitory factor (PRL-IF), a 35-45 K Mr protein that is released by the decidua. The secondary increase in the synthesis and release of prolactin in response to PRF-RF is blocked by lipocortin I, which is synthesized by both the placenta and decidua. IGF-I, insulin and relaxin also stimulate the synthesis and release of prolactin. However, the stimulation in response to these factors does not occur until 24-48 h after exposure. The cellular mechanisms involved in the release of decidual prolactin are as yet unknown. However, recent studies implicate activation of adenylate cyclase, phospholipase C-mediated phosphoinositide hydrolysis and phospholipase A2-mediated arachidonic acid release in the regulation of prolactin release. The finding that the synthesis and release of decidual prolactin are regulated, at least in part, by PRL-RF, IGF-I, insulin, relaxin and lipocortin I strongly suggests that there is novel feedback regulation between the placenta, fetal membranes, and decidua in the regulation of the synthesis and release of decidual prolactin.

Vision research in departments of ophthalmology. An Association of University Professors of Ophthalmology perspective

A research committee of the Association of University Professors of Ophthalmology disseminated a survey questionnaire to determine the state of research in departments of ophthalmology across the United States. The questionnaire contained 71 questions that were designed to assess attitudes and trends within members' departments and to solicit suggestions from the membership. Of the 145 members and affiliates queried, 140 responded. While the results of the survey indicate significant diversity among departments, departmental chairpersons view research as a major priority in the goals of their departments, and they envision maintenance or expansion of research over the next decade. The survey results have been collated and serve now as the basis for this Association of University Professors position article.

Operative treatment of palsy of the posterior interosseous nerve of the forearm

The cases of forty patients who were operated on consecutively for palsy of the posterior interosseous nerve were analyzed. The injury was iatrogenic in sixteen patients, traumatic in fifteen, and nontraumatic in nine. Persistent paralysis (partial or complete) was the only indication for operation. Operative neurolysis was done in twenty-three patients; interfascicular nerve-grafting, in twelve; internal neurolysis, in one; and tendon transfer, in four. An excellent or good functional result was documented for all but three patients, of whom two had had neurolysis and one, nerve-grafting.

Evidence that mammalian ribonucleotide reductase is a nuclear membrane associated glycoprotein

Epitope-specific antibodies to the M1 and M2 subunits of mammalian ribonucleotide reductase were prepared using peptides predicted to have a high antigenic index. Western blotting demonstrated that the anti-M1 antibody was specific for the 89-kilodalton M1 subunit (and its degradation fragments) and the anti-M2 antibody specifically recognized the 45-kilodalton M2 subunit. Both antibodies inhibited the CDP-reductase activity of the holoenzyme. Using these antibodies, both the M1 and M2 subunits were shown to be localized in the cytoplasm and in the nuclear regions of a number of cell types, including B77 avian sarcoma virus transformed NRK cells, T51B rat liver cells, 5123tc hepatoma cells, and rat liver cells in vivo. In addition, the M1 subunit was found to be localized as a halo around isolated rat liver nuclei. Biochemical analysis of the cytoplasmic fraction of liver cells and a Triton X-100 wash of nuclei from these cells confirmed the location of the enzyme activity in these cellular compartments. The M1 subunit appears to be glycosylated, as indicated by its retention on a Affi-Gel-concanavalin A affinity column. Therefore, in mammalian cells ribonucleotide reductase appears to be not only in the cytoplasm, but is also associated with the nuclear membrane or nuclear lamina. The activity of the enzyme in the membrane fraction changes dynamically during the cell cycle.

Disposition, pharmacokinetics, and metabolism of 14C-fotemustine in cancer patients

The pharmacokinetics and metabolism of intravenously infused 14C-fotemustine (about 100 mg/m2) were examined in 2 cancer patients. Plasma levels of radioactivity increased to a maximum of 4.1 and 5.5 micrograms equivalents per g when the infusion stopped then declined triexponentially with mean half-lives of about 1/2, 10 and 80 h for the initial, mid and terminal phases, respectively. Plasma levels of intact drug were lower, with maximum levels of 1.1 and 2.8 micrograms/ml, and declined monophasically with a half-life of about 24 min. Plasma clearance was high (1426 and 764 ml/min) with the volume of distribution based on areas of 47.7 and 26.4 l. Most of the radioactivity was eliminated in urine (50.1 and 61.3%) over 7 days with smaller amounts in the feces (6.8 and 0.3%) and only minimal quantities (under 0.1%) as expired carbon dioxide. Metabolites of fotemustine were identified as chloroethanol and N-nitroso-1-imidazolone-ethyl-diethylphosphonate in plasma and as 1-hydantoin-ethyl-diethyl-phosphonate and acetic acid in urine.

Non-neurogenic soft tissue tumours of the axilla: prospective review of 16 cases

Sixteen consecutive patients entered in a prospective study of non-neurogenic soft tissue tumours had lesions in the axilla. Delayed diagnosis and inappropriate biopsy prior to referral to a surgical oncologist were frequent findings. Sarcoma and fibromatosis were diagnosed in 14 cases, and the approaches used for these two diseases were fundamentally different. The functional outcome with limb salvage surgery in these patients is presented.

Application of 3-D computer graphics for facial reconstruction and comparison with sculpting techniques

Facial reconstruction has until now been carried out by the sculpting technique. This method involves building a face with clay or other suitable material on to a skull or its cast, taking into account appropriate facial thickness measurements together with information provided by anthropologists such as approximate age, sex, race and other individual idiosyncrasies. A method for facial reconstruction is presented using 3-D computer graphics and is compared with the manual technique. The computer method involves initially digitising a skull using a laser scanner and video camera interfaced to a computer. A face, from a data bank which has previously digitised facial surfaces, is then placed over the skull in the form of a mask and the skin thickness is altered to conform with the underlying skull. The advantage of the computer method is its speed and flexibility. We have shown that the computer method for reconstructing a face is feasible and furthermore has the advantage over the manual technique of speed and flexibility. Nevertheless, the technique is far from perfect. Further facial thickness data needs collecting and the method requires evaluation using both known control skulls and later unknown remains.

Deep inspiration increases the absorption of inhaled sodium cromoglycate

The plasma concentrations of sodium cromoglycate were measured for 4 h following a single dose of 20 mg given by inhalation to six normal volunteers. A series of forced expiratory manoeuvres was performed 2 h after the dose, which resulted in a rapid and marked increase in the plasma concentrations of the drug. A similar increase was found in three volunteers who undertook a single deep inspiration at 4 h. These data indicate that the absorption of cromoglycate from the airways can be affected by manoeuvres used to assess lung function.

Nedocromil sodium is more potent than sodium cromoglycate against AMP-induced bronchoconstriction in atopic asthmatic subjects

Nedocromil sodium is a new chemical entity which shows similar properties to sodium cromoglycate (SCG) and in addition exhibits a preferential activity in stabilizing mucosal mast cells. We have compared the effect of inhalation of nebulized placebo, SCG and nedocromil sodium on the bronchoconstrictor response to inhaled adenosine monophosphate (AMP) in eight atopic asthmatic subjects aged 25 yr (range 21-32 yr). The geometric mean provocation doses of AMP required to produce a 20% decrease in FEV1 (PD20FEV1) and a 40% decrease in Vmax30 (PD40 Vmax30) following placebo were 4.9 (0.3-14.2) and 1.8 (0.1-8.4) mumol respectively. Prior inhalation of both SCG and nedocromil sodium significantly inhibited the bronchoconstrictor response to AMP with PD20FEV1s of 36.6 (4.0-132.7) and 134 (12.4-560), and PD40 Vmax30 values of 20.5 (1.4-110) and 101.6 (5-560) mumol respectively (P less than 0.001). Nedocromil sodium was 3.9 (FEV1) and 8.0 (Vmax30) times more potent than SCG (P less than 0.001). In conclusion, both drugs inhibit the bronchoconstrictor response to inhaled AMP, and nedocromil is at least 4-8 times more potent than SCG.

Pseudo-shading technique in the two-dimensional domain: a post-processing algorithm for enhancing the Z-buffer of a three-dimensional binary image

Three-dimensional (3D) medical graphics is becoming popular in clinical use on tomographic scanners. Research work in 3D reconstructive display of computerized tomography (CT) and magnetic resonance imaging (MRI) scans on conventional computers has produced many so-called pseudo-3D images. The quality of these images depends on the rendering algorithm, the coarseness of the digitized object, the number of grey levels and the image screen resolution. CT and MRI data are fundamentally voxel based and they produce images that are coarse because of the resolution of the data acquisition system. 3D images produced by the Z-buffer depth shading technique suffer loss of detail when complex objects with fine textural detail need to be displayed. Attempts have been made to improve the display of voxel objects, and existing techniques have shown the improvement possible using these post-processing algorithms. The improved rendering technique works on the Z-buffer image to generate a shaded image using a single light source in any direction. The effectiveness of the technique in generating a shaded image has been shown to be a useful means of presenting 3D information for clinical use.

Effect of nedocromil sodium and sodium cromoglycate against bronchoconstriction induced by inhaled adenosine 5'-monophosphate

In this randomized, double-blind, placebo controlled study, the effect of prior inhalation of nebulized sodium cromoglycate (SCG) (7.3 +/- 0.6 mg) and nedocromil sodium (NED) (7.5 +/- 0.6 mg) was observed on adenosine 5'-monophosphate (AMP)-induced bronchoconstriction in 11 non-atopic asthmatic subjects. The geometric mean provocation doses of methacholine and AMP required to produce a 20% decrease in forced expiratory volume in one second (FEV1) (PD20FEV1) were 0.6 (0.1-18.8) and 5.1 (0.8-130.7) mumole respectively. The repeatability of the AMP challenge procedure for PD20FEV1 was within one doubling dose difference. SCG and NED, administered 30 min prior to bronchoprovocation with AMP, displaced the AMP dose-response curve to the right by 9.6 (1.5-41.6) (p less than 0.01) and 22.2 (3.7-89.1) (p less than 0.01)-fold, respectively, the difference between the two drugs being significant (p less than 0.05). There was a significant correlation (r = 0.7, p = 0.02) between the log dose ratios for PD20FEV1 for SCG and NED. We conclude that both SCG and NED protect against AMP-induced bronchoconstriction, NED being at least 2.3 (0.7-11.5)-fold more potent than SCG, and that they achieve this effect by a similar mechanism(s).

Effect of nedocromil sodium and sodium cromoglycate against bronchoconstriction induced by inhaled adenosine 5'-monophosphate

In this randomized, double-blind, placebo controlled study, the effect of prior inhalation of nebulized sodium cromoglycate (SCG) (7.3 +/- 0.6 mg) and nedocromil sodium (NED) (7.5 +/- 0.6 mg) was observed on adenosine 5'-monophosphate (AMP)-induced bronchoconstriction in 11 non-atopic asthmatic subjects. The geometric mean provocation doses of methacholine and AMP required to produce a 20% decrease in forced expiratory volume in one second (FEV1) (PD20FEV1) were 0.6 (0.1-18.8) and 5.1 (0.8-130.7) mumole respectively. The repeatability of the AMP challenge procedure for PD20FEV1 was within one doubling dose difference. SCG and NED, administered 30 min prior to bronchoprovocation with AMP, displaced the AMP dose-response curve to the right by 9.6 (1.5-41.6) (p less than 0.01) and 22.2 (3.7-89.1) (p less than 0.01)-fold, respectively, the difference between the two drugs being significant (p less than 0.05). There was a significant correlation (r = 0.7, p = 0.02) between the log dose ratios for PD20FEV1 for SCG and NED. We conclude that both SCG and NED protect against AMP-induced bronchoconstriction, NED being at least 2.3 (0.7-11.5)-fold more potent than SCG, and that they achieve this effect by a similar mechanism(s).

Hurricane Gilbert devastated Carribean medical school

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Ribonucleotide reductase--new twists in an old tale

Although they are proliferatively quiescent, the cells in the intact adult rat liver express the gene coding for the M1 subunit of ribonucleotide reductase. But since they do not need deoxyribonucleotides, they promptly inactivate the 88 to 90 kDa M1 products and degrade them into 40 kDa fragments. Partial hepatectomy signals the remaining cells to start proliferating. Two hours before the onset of DNA replication, around 16 to 18 hr after partial hepatectomy, the cells start accumulating a large pool of functional ribonucleotide reductase M2 subunits. Near the end of the G1 build-up the cells step up M1 gene expression, stop inactivating, and reduce the degradation of the M1 products. The accumulating functional 88 to 90 kDa M1 subunits, each with more than one catalytic site, couple with functional M2 subunits to produce active ribonucleotide reductase holoenzyme which accumulates in the outer nuclear membrane from which they supply deoxyribonucleotide precursors to intranuclear replication enzymes. At the end of the S phase, the cell reduces M1 gene expression and resumes degrading 88 to 90 kDa M1 subunits. At least some of the 40 kDa M1 fragments are still active and can form partially active "holoenzymes" when mixed with a standard preparation of functional M2 subunits. The M1 control mechanism appears not to operate in hepatoma cells and Ehrlich ascites tumor cells, both of which maintain a pool of undegraded 88 to 90 kDa M1 components.

Airway refractoriness to adenosine 5'-monophosphate after repeated inhalation

Adenosine-5'-monophosphate (AMP) is a bronchoconstrictor agonist in subjects with atopic and nonatopic asthma. In this study we have investigated the effect of repeated airway challenge with AMP in 10 atopic, subjects without asthma. At the first visit, subjects had repeated inhalation challenges with increasing doubling concentrations of AMP, and the provocation concentration required to reduce FEV1 by 20% of baseline was determined (PC20 AMP). When the FEV1 had returned to within 5% of the baseline, the AMP challenge test was repeated on a further one or two occasions. When the maximum concentration of AMP (400 mg/ml) failed to produce a PC20, a bronchial provocation test with histamine was performed and the PC20 was determined. On the second visit, the effect of three consecutive inhalation challenge tests with histamine on the airway response to this agonist was determined. On the third visit, the duration of induced refractoriness to AMP was assessed. With the first AMP challenge, all subjects demonstrated bronchoconstriction with a geometric mean (GM) PC20 of 332 mg/ml. With a second AMP challenge, five of the 10 subjects became refractory and failed to achieve a PC20. In the remaining five subjects, the GM PC20 increased from 110 to 583 mg/ml. With a third AMP challenge, these subjects also failed to achieve a PC20. The initial GM PC20 histamine for the group was 22.9 mg/ml, which did not change significantly with two further histamine challenges or when the airways were refractory to AMP, suggesting that loss of AMP effect was not related to loss of contractility of airway smooth muscle or down regulation of H1-histamine receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Supracondylar fractures of the humerus--results of surgical treatment

Forty-eight patients with supracondylar fractures of the humerus have been treated at St. Michael's Hospital in the past 10 years. Forty-six of the 48 were treated surgically. A comparison was made between the use of standard AO (ASIF) plates with a pre-contoured plate especially designed for the distal humerus. The results of this comparison suggested that the specifically designed plate provided superior fixation and better anatomic restoration of the distal humerus. Anatomic reduction, rigid fixation, and early surgery provide the best results.

Inhalation rate of sodium cromoglycate determines plasma pharmacokinetics and protection against AMP-induced bronchoconstriction in asthma

We have investigated whether the inspiratory flow at which sodium cromoglycate (SCG) is inhaled influences the efficacy of SCG. Seven atopic asthmatic subjects (age 25 +/- 2 yrs) inhaled dry powder SCG from a Spinhaler on separate occasions at three flow rates, maximum (V1), 100 l.min-1 (V2), and 50 l.min-1 (V3), or placebo, according to a double-blind structured study. Thirty minutes after administration a bronchial provocation test was performed with adenosine 5'-monophosphate (AMP). Blood samples for measurement of plasma SCG concentration were taken and the area under the plasma concentration-time curve (AUC) calculated for each flow rate. Both inspiratory flow rate and AUC correlated significantly with the degree of protection afforded against AMP-induced bronchoconstriction (r = 0.73, p less than 0.001; r = 0.66, p less than 0.001). These findings indicate that the flow rate used to inhale powdered SCG is a major factor in determining the protective efficacy of this drug against bronchial challenge and therefore has important clinical implications.

Inhalation rate of sodium cromoglycate determines plasma pharmacokinetics and protection against AMP-induced bronchoconstriction in asthma

We have investigated whether the inspiratory flow at which sodium cromoglycate (SCG) is inhaled influences the efficacy of SCG. Seven atopic asthmatic subjects (age 25 +/- 2 yrs) inhaled dry powder SCG from a Spinhaler on separate occasions at three flow rates, maximum (V1), 100 l.min-1 (V2), and 50 l.min-1 (V3), or placebo, according to a double-blind structured study. Thirty minutes after administration a bronchial provocation test was performed with adenosine 5'-monophosphate (AMP). Blood samples for measurement of plasma SCG concentration were taken and the area under the plasma concentration-time curve (AUC) calculated for each flow rate. Both inspiratory flow rate and AUC correlated significantly with the degree of protection afforded against AMP-induced bronchoconstriction (r = 0.73, p less than 0.001; r = 0.66, p less than 0.001). These findings indicate that the flow rate used to inhale powdered SCG is a major factor in determining the protective efficacy of this drug against bronchial challenge and therefore has important clinical implications.

A clinical trial of the efficacy and acceptability of D-fenfluramine in the treatment of neuroleptic-induced obesity

Twenty-nine overweight schizophrenic patients maintained on depot neuroleptic injections who wished to lose weight took part in a double-blind, placebo-controlled trial of 30 mg D-fenfluramine. All subjects received dietary advice. Sixteen patients completed the 12-week trial. Rate of weight loss was significantly greater in those taking D-fenfluramine. Side-effects were reported, but no deterioration in mental state was noted.

Effect of methacholine induced bronchoconstriction on the pulmonary distribution and plasma pharmacokinetics of inhaled sodium cromoglycate in subjects with normal and hyperreactive airways

Inhalation treatment may be less effective in the presence of bronchoconstriction because of the reduced penetration of drugs into the airways. The effect of bronchoconstriction on the lung deposition and plasma pharmacokinetics of inhaled sodium cromoglycate was examined. Ten subjects attended the laboratory on three occasions. On the first occasion a bronchial provocation test was performed to determine the concentration of methacholine required to reduce the forced expiratory volume in one second (FEV1) by 20% (PC20). On the two subsequent occasions subjects inhaled either saline or their PC20 methacholine, followed five minutes later by an aerosol containing sodium cromoglycate and stannous phytate labelled with technetium-99m. Twenty minutes later a gamma emission lung scan was performed to determine the intrathoracic deposition of the nebulised aerosol. The central:peripheral (C:P) ratio of lung deposition was then calculated. Measurements of FEV1 were made and blood samples taken for analysis of plasma sodium cromoglycate concentration at intervals for four hours. Methacholine led to a 23.4% (SEM 0.6%) lower FEV1 and a 2.8 times higher C:P ratio than those observed after saline. There was a direct correlation between log PC20 methacholine and the increase in the C:P ratio (r = 0.81). Despite these changes with methacholine, the plasma pharmacokinetics of inhaled sodium cromoglycate were not significantly different after methacholine and after saline, except that the maximum concentration achieved (Cmax) was increased. These observations suggest that the area of cromoglycate deposition and the anatomical site are less important in determining the plasma pharmacokinetics of cromoglycate than is the total dose delivered to the lung.

Decidual prolactin (PRL)-releasing factor stimulates the synthesis of PRL from human decidual cells

Previous studies from our laboratory demonstrated that the acute release of PRL from human decidual tissue is stimulated by a 23.5 kilodalton placental protein which we designated decidual PRL-releasing factor (PRL-RF). To determine whether PRL-RF may also affect the synthesis of PRL and/or cause a secondary increase in PRL release, we have examined the effects of purified PRL-RF on the synthesis and release of PRL over a 96-h period. Exposure of dispersed decidual cells to PRL-RF (0.5 microgram/ml) stimulated a biphasic increase in PRL release with acute transient stimulation during the first 0.5 h and a delayed and sustained stimulation beginning about 8 h after exposure which persisted for the duration of the 96 h. The amounts of PRL released from PRL-RF-exposed cells after 0.5, 8, 12, 24, and 96 h were 321.2 +/- 36.2 (mean +/- SEM, n = 3), 110.2 +/- 5.3, 138.2 +/- 7.2, 194.5 +/- 11.2, and 201.5 +/- 14.2% that of control cells. Studies of the de novo synthesis of [35S]methionyl PRL indicated that the increase in PRL release after the first few hours of exposure to PRL-RF was secondary to an increase in PRL synthesis. Somatostatin (100 nM) inhibited the acute stimulatory effect of PRL-RF, but had no effect on the delayed stimulation of PRL release. On the other hand, cycloheximide (20 microM) completely inhibited the secondary increase in PRL release in response to PRL-RF but had no effect on the acute release. These results demonstrate that PRL-RF stimulates both the synthesis and release of decidual PRL.

Essential iris atrophy. A clinical, immunohistologic, and electron microscopic study in an enucleated eye

A 29-year-old woman had unilateral essential iris atrophy, corneal endothelial changes, and absolute glaucoma. The enucleated eye was examined by routine light microscopy. Separate portions of unfixed fresh frozen cornea were sectioned and reacted with monoclonal antibodies against keratins, vimentin, and inflammatory cell markers. Stains for filamentous actin (f-actin) were performed using the 7-nitro-benz-2-oxa-1,3-diazolylphallacidin (NBD phallacidin) probe. In addition, portions of cornea and iris were examined by scanning and transmission electron microscopy. Immunocytochemical stains with anti-keratin antibodies showed reactivity only in the corneal epithelium of the patient and normal control. Immunoreactivity with anti-vimentin antibodies was observed in corneal endothelium and keratocytes of the patient and control, but was negative in the epithelium. Staining for f-actin appeared more pronounced in the corneal endothelium of the patient. Scanning electron microscopy of the corneal endothelium showed irregularity in cell size and shape and filopodial processes characteristic of migrating cells. Transmission electron microscopy disclosed abnormalities of Descemet's membrane and endothelium with a posterior collagenous layer. The corneal endothelium displayed normal junctional complexes without desmosomal junctions or increased microvillus projections. Increased 10-nm cytoplasmic filaments were noted consistent with the expression of vimentin. Occasional chronic inflammatory cells perturbed the corneal endothelium and were detected within the endothelial layer. Alterations in the endothelium and Descemet's membrane suggest the acquired nature of this disease.

Somatosensory evoked potential monitoring accurately predicts hemi-spinal cord damage: a case report

Separate somatosensory evoked potentials (SEPs) were monitored from each lower extremity during instrumentation for a spinal fracture. The SEP disappeared from the right lower extremity after instrumentation, but not from the left lower extremity. The predicted hemi-spinal cord injury was pathologically confirmed. The merits of sequential, as opposed to simultaneous, stimulation of multiple extremities during surgical monitoring are discussed.

Isotype and cytotoxicity spectra of anti-lymphocyte antibodies in patients with systemic lupus erythematosus

IgG anti-lymphocyte antibodies (ALA) reactive with resting lymphocytes were demonstrated in sera of patients with systemic lupus erythematosus (SLE) by immunofluorescence and flow cytometry and were shown (i) to bind T cells by non-Fc receptor-related mechanisms, (ii) to potentiate antibody-dependent cellular cytotoxicity (ADCC) of lymphocytes in vitro which correlated with binding to T cells, and (iii) to occur at a similar frequency in 29 SLE sera (56%) as IgM ALA (59%). IgG ALA levels in sera negatively correlated with absolute numbers of circulating lymphocytes in patients (r = -0.48, P less than 0.05), as did IgM ALA levels (r = -0.54, P less than 0.05); however, a stronger correlation resulted when levels of both ALA isotypes were considered together (r = -0.61, P less than 0.01). Different groups of SLE patients were distinguished with respect to relative serum content of IgM and IgG ALA and corresponding serum capacity to predominantly mediate ADCC, complement-dependent cytotoxicity (CDC), or both. No correlation existed between serum ADCC and CDC activities in vitro (r = 0.22). However, SLE patient lymphocyte counts negatively correlated with ADCC (r = -0.59, P less than 0.01) and to a lesser but still significant extent with CDC (r = -0.47, P less than 0.05). The latter results suggested that ADCC, induced by serum IgG ALA, was a mechanism of cytoloysis which occurred independently of CDC and which, like CDC, was significantly associated with lymphopenia in vivo.

Effects of aortic occlusion on regional spinal cord blood flow and somatosensory evoked potentials in sheep

Somatosensory evoked potentials (SEPs) were recorded continuously during aortic occlusion in sheep, with simultaneous measurement of spinal cord blood flow (SCBF) by radiolabeled microspheres. Aortic occlusion was associated with disappearance of the SEPs in seven of nine sheep in 7.8 +/- 4.1 (SD) minutes. SCBF at the time of initial cross clamping and 30 minutes after the onset of ischemia revealed a severe reduction in white and gray matter flow in the thoracolumbar cord. Release of the aortic clamp was associated with reactive hyperemia in these ischemic regions. In two animals, the SEP persisted during aortic cross clamping. The total SCBF in the thoracic and lumbar regions of these two animals exceeded 20 ml/100 g/min after 30 minutes of ischemia and was significantly greater than the flow recorded in sheep whose evoked response disappeared. The relation between spinal cord ischemia and evoked potential alterations is discussed in detail.

Comparison of the airway response to eye drops of timolol and its isomer L-714,465 in asthmatic subjects

1. The inadvertent administration of timolol to asthmatic patients continues to cause occasional severe and even fatal attacks of asthma. The (R)-enantiomer of timolol, L-714,465, is four times less potent than timolol in reducing intraocular pressure in man. It is 49 times less potent than timolol on beta 2-adrenoceptors in animals and 13 times less potent on the airways of normal subjects. These findings suggested that L-714,465 might be a safer alternative for the treatment of glaucoma. 2. Ten subjects with mild asthma who bronchoconstricted to timolol eye drops (0.25 or 0.5%) were studied. Airway dose-response curves to timolol (0-2%), L-714,465 (0-4%), and placebo (methyl cellulose) eye drops were performed in a double-blind randomised study in which airway response was measured as change in FEV1 and specific airway conductance (sGaw). 3. L-714,465 and timolol caused dose dependent falls in sGaw and FEV1 with L-714,465 being approximately four times less potent than timolol. The geometric mean dose ratio was 3.89 for FEV1 (95% confidence interval (CI) 1.7-8.7) and 3.93 (95% CI 2-7.8) for sGaw. Since the difference in potency is similar to the reported difference in potency of the two drugs on intraocular pressure we conclude that L-714,465 would not have a greater safety margin than timolol. 4. After completion of the dose-response study eight subjects inhaled ipratropium bromide (72 micrograms) and this caused an increase in FEV1 from 74% to 80% of baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification of decidual prolactin-releasing factor, a placental protein that stimulates prolactin release from human decidual tissue

Decidual prolactin-releasing factor (PRL-RF), a placental protein that stimulates the release of prolactin from human decidual tissue, has been purified from conditioned medium of human placental explants. The purification scheme consisted of ethanol extraction, anion exchange chromatography on DEAE-cellulose, size exclusion chromatography on Spherogel TSK-3000, and either a) immunoaffinity chromatography using an antiserum to a partially purified PRL-RF preparation or b) acetic acid-urea/SDS 2-dimensional PAGE. The apparent molecular weight of the purified releasing factor, estimated by SDS-PAGE, was 23,500 Da; and the half-maximal dose for the acute stimulation of prolactin release from human decidual cells was 0.05-0.1 ug/ml (2.2-4.4 nM).

Absorption and disposition kinetics of cromolyn sodium and the influence of inhalation technique

Plasma concentrations of cromolyn sodium (SCG) have been measured in 13 normal subjects on three occasions after inhalation from a Spinhaler (20 mg) delivery system under conditions of controlled inspiratory flow rate. High inspiratory flow rates were associated with high peak plasma concentrations and areas under the plasma concentration-time curve. A 10-sec breath hold at the end of inspiration did not alter significantly the plasma concentration-time curve. Instillation of SCG (1 mg) directly into a second-order bronchus of 14 patients undergoing diagnostic examination gave plasma concentration-time curves similar to those seen in normal volunteers at high inspiratory flow rates. Additional studies in normal volunteers showed that SCG was poorly absorbed from the gastrointestinal tract. The shorter terminal half-life seen after i.v. infusion compared with inhalation indicates that the drug shows absorption rate limited disposition kinetics after inhalation. These studies in large numbers of subjects support the conclusions of limited earlier investigations that SCG is absorbed slowly but almost completely from the airways, that there is little gastrointestinal absorption of SCG, that only a small proportion of the Spinhaler dose (about 10%) reaches the airways and that the amount reaching the airways is related directly to inspiratory flow rate.

Heat shrinkage of extraocular muscle tendon

We have designed and employed a bipolar heating device to shorten extraocular muscles. Treatment involves placing the unidirectional heating device on the sclera with the active surface beneath the tendinous portion of the extraocular-muscle. When power is applied, visible tissue shrinkage occurs. Heat-induced extraocular muscle shrinkage was performed on live rhesus monkeys. Two months later, thermal tendinoplasty-treated extraocular muscles were surgically isolated and evaluated for strength. Biopsies were then performed on these muscles. It was our clinical impression that treated tissues retained their strength, while histologic and electron-microscopic evaluation of heat-treated tendon revealed evidence of shrinkage and compaction of collagen bundles. Thermal tendinoplasty may offer a sutureless method of correcting strabismus by shortening and thereby strengthening extraocular muscles.

Red cell genetic abnormalities in Peninsular Arabs: sickle haemoglobin, G6PD deficiency, and alpha and beta thalassaemia

The frequencies of four major red cell genetic defects, sickle haemoglobin (Hb S), glucose 6 phosphate dehydrogenase deficiency (G6PD), and alpha and beta thalassaemia, have been determined in nearly 5000 subjects from the three major Peninsular Arab States, namely Yemen (North and South), the United Arab Emirates, and Oman. All four defects are common with an overall pattern of alpha thalassaemia greater than G6PD deficiency greater than beta thalassaemia greater than Hb A/S. However, the frequencies of these within each state varies and they are, respectively, Oman: 0.389, 0.328, 0.024, and 0.038; the United Arab Emirates: 0.165, 0.087, 0.017, and 0.019; and Yemen: 0.065, 0.062, 0.0624, and 0.0095. Two, namely alpha thalassaemia and G6PD deficiency, are extremely common, but in spite of this there appears to be a lack of observed clinical disease. For example, Hb H disease and Barts hydrops fetalis were not seen and the oxidative haemolytic syndromes are rare.

Iron state in alpha and beta thalassaemia trait

The iron state was examined in two groups of pregnant women who were carriers of alpha and beta thalassaemia genes. In both groups the haematological expression of the disease--namely, haemoglobin and mean cell haemoglobin concentrations--was nearly identical. In patients with alpha thalassaemia the ferritin concentrations and percentage of ferritin deficiency was the same as in normal pregnant patients, whereas in those with beta thalassaemia the ferritin concentrations were usually much higher and iron deficiency four times less common. This variance appears to be explained by different degrees of extravascular or intravascular haemolysis between the two thalassaemias as assessed by the activities of serum alpha hydroxybutyrate dehydrogenase.

Bronchial beta-adrenoceptor blockade following eyedrops of timolol and its isomer L-714,465 in normal subjects

The R-enantiomer of timolol, L-714,465, is considerably less potent as a beta 1- and beta 2-adrenoceptor antagonist in animals than timolol, whilst only slightly less potent in reducing intraocular pressure. If the same was true in man L-714,465 would have potential benefits over timolol in the treatment of glaucoma. The extent of bronchial beta-adrenoceptor blockade following one eyedrop in each eye of timolol 1% and L-714,465 1% was compared in six normal subjects, by measuring the displacement of the bronchodilator dose-response curve to isoprenaline following each drug compared to the isoprenaline dose-response curve after placebo eyedrops (methyl-cellulose). There was no significant difference between the dose-response curves to L-714,465 and placebo, but a significant displacement of the dose-response curve following timolol. The geometric mean dose ratio following timolol (21) differed significantly from that following L-714,465 (1.6). Heart rate at the end of the isoprenaline dose-response study was lower after timolol, despite the fact that subjects had received higher doses of isoprenaline. The trend was in the same direction after L-714,465 when compared with placebo though less marked. L-714,465 clearly causes less beta-adrenoceptor blockade than timolol when given as 1% eyedrops. The effects of L-714,465 1% on the airways and heart rate did not differ significantly from placebo in these six subjects but the pattern of response would be most consistent with L-714,465 having some beta-adrenoceptor blocking activity though considerably less than timolol.

Thalassaemia trait and pregnancy

The haematological variables, haematinic state, and placental function of more than 2000 pregnant women, heterozygous for either alpha- or beta-thalassaemia genes, were examined during pregnancy. Four features emerged. Firstly, it was possible by discriminant function analysis of haematological variables to distinguish in pregnant patients between the anaemia caused by thalassaemia trait and that caused by iron deficiency. Secondly, patients with thalassaemia become significantly more anaemic in pregnancy, beta more than alpha, but this was mainly due to plasma dilution. From the data percentile curves were drawn for each type of thalassaemia which predicted the patients' expected "normal" haemoglobin throughout gestation. Thirdly, patients with alpha-thalassaemia had the same incidence of iron deficiency as normal pregnant patients, whereas in those with beta-thalassaemia it was four times less common. The incidence of folic acid and vitamin B12 deficiency was the same in all groups. Finally, as assessed by serum oestriol concentration, there did not appear to be any abnormality of placental function or fetal development associated with maternal thalassaemia, and, also, there seemed to be no increase in maternal or fetal morbidity in pregnancy.