The function of the midtarsal joint: a review of the literature.

The midtarsal joint (MTJt) consists of the combined articulations of the talonavicular and calcaneocuboid joints and represents the functional articulation between the rearfoot (talus and calcaneus) and the midfoot (navicular and cuboid). The movement of the transverse tarsal region has been described as a segment rotating around two distinct axes of the MTJt; the longitudinal and the oblique. Recent research has suggested that the two axes model of the MTJt is a theory of convenience to explain clinical observation, and that the MTJt moves in a more complex manner. It has been hypothesised that the MTJt has one triplanar axis of motion, so there remains the need to investigate the practical application of this understanding in terms of how this motion affects the MTJt in gait and the implications this may have on podiatric treatment.

Use of salivary biomarkers in biobehavioral research: cotton-based sample collection methods can interfere with salivary immunoassay results.

In a series of studies, we evaluated the susceptibility of immunoassays for saliva biomarkers to interference effects caused by cotton materials used to absorb saliva during sample collection. Salivary assay results for testosterone, DHEA, progesterone, and estradiol are artificially high, and for sIgA artificially low, when samples are collected using cotton absorbent materials. In contrast, results for salivary cortisol, DHEA-S, and cotinine are not affected by the use of cotton collection methods. The order of individual results from samples collected using cotton versus no-cotton methods for certain markers is not conserved, suggesting that for some biomarkers this collection method can be a significant source of unsystematic error. It was shown, using DHEA as an example, that the cotton interference effect is of sufficient magnitude to attenuate the association between serum and saliva levels. Awareness of this issue is critical to ensure measurement validity in future studies and analyses of archived samples collected using cotton materials.

Interventional techniques in the management of chronic pain: Part 2.0.

The practice guidelines for interventional techniques in the management of chronic pain are systematically developed statements to assist physician and patient decisions about appropriate health care related to chronic pain. These guidelines are professionally derived recommendations for practices in the diagnosis and treatment of chronic or persistent pain. They were developed utilizing a combination of evidence and consensus based techniques, to increase patient access to treatment, improve outcomes and appropriateness of care, and optimize cost-effectiveness. The guidelines include a discussion of their purpose, rationale, and importance, including the patient population served, the methodology and the pathophysiologic basis for intervention. Various interventional techniques will be discussed addressing the rationale for their use in chronic pain with analysis of the outcomes data and cost effectiveness. These guidelines do not constitute inflexible treatment recommendations. It is expected that a provider will establish a plan of care on a case-by-case basis, taking into account an individual patient's medical condition, personal needs, and preferences, and the physician's experience. Based on an individual patient's needs, treatment different from that outlined here could be warranted.

Assessing estradiol in biobehavioral studies using saliva and blood spots: simple radioimmunoassay protocols, reliability, and comparative validity.

We developed simple, reliable, and highly sensitive assay modifications of commercially available radioimmunoassay kits to measure estradiol in saliva and blood spot specimens. The saliva assay has average intra- and interassay coefficients of variation (CV) of 6.45 and 9.01%, with average analytical and serial dilution recoveries 100.65 and 89.25%. The blood spot assay has average intra- and interassay CVs of 7.57 and 8.22%, with analytical and serial dilution recoveries of 80.50 and 108.50%. The analytical sensitivity ranges of the saliva (0.25-7.50 pg/ml) and blood spot (2. 00-375 pg/ml) assays are sufficient to determine levels in the majority of pre- and postpubertal males and females. Blood spot assay results are correlated with serum estradiol levels for adult males, r (17) = 0.73, and females, r (18) = 0.96. In contrast, the serum-saliva correlation is only modest for adult females, r (14) = 0.60, and not significant for adult males. Substitution of blood spot assay results for serum values underestimates the known serum estradiol-behavior correlation by only 3.45%, whereas substitution of saliva assay results for serum values underestimates the association by 37.55%. The findings have important implications for the use and potential misuse of noninvasive measures of estradiol in studies of health and human development.

Treatment of high-grade low-stage prostate cancer by high-dose-rate brachytherapy.

BACKGROUND AND PURPOSE: The best management of patients with low-stage, high-grade prostate cancer remains unclear. In an attempt to improve the outcomes of this high-risk group, we have offered those with Gleason > or =7 cancers removable-source high-dose-rate (HDR) brachytherapy in combination with external-beam radiation. PATIENTS AND METHODS: We reviewed the clinical histories of 61 consecutive patients with high-grade clinical stage T1-T2 lesions who received the combination radiation therapy between March 1997 and November 1998. The average Gleason score was 7.5. The HDR brachytherapy was given in three sessions with removable-source afterloaded (192)Ir to a minimum peripheral dose of 6 Gy. Conformal external-beam radiation in 25 fractions to a dose of 50 Gy was given beginning 1 week later. Patients with prostate volumes >40 cc received a luteinizing hormone-releasing hormone analog before brachytherapy. RESULTS: Among the 52 patients available for follow-up (average duration 11.8 months), there has been one death from prostate cancer. After treatment, only one patient had an initial rise in serum prostate specific antigen (PSA) concentration. In addition to the patient who died, there have been three confirmed treatment failures. Toxicity was mild, with only two patients having RTOG grade 3 or 4 effects. Neither of them required surgery. CONCLUSION: Although long-term results are not available, available data suggest that HDR brachytherapy plus external-beam radiation is at least as effective as any single therapy for high-risk, low-stage prostate cancer. The toxicity is acceptable.

The overactive bladder in childhood: long-term results with conservative management.

PURPOSE: Idiopathic detrusor overactivity has not been thoroughly investigated and its natural history remains largely anecdotal. Bladder overactivity resulting from a neurogenic, anatomical or medical condition has been well described. Therefore, we assessed the long-term results of conservative treatment of children with idiopathic symptomatic refractory detrusor instability. MATERIALS AND METHODS: We reviewed the records of 58 patients who had an isolated finding of uninhibited contractions on urodynamics performed for refractory enuresis and daytime wetting between 1988 and 1994. Study exclusion criteria were chronic urinary tract infection, neurological lesion, anatomical abnormality of the lower urinary tract and less than 12 months of followup. RESULTS: Of the 30 children who met our study inclusion criteria 26 (87%) had complete (21) or significant (5) symptom resolution. Average time to resolution was 2.7 years (range 0.2 to 6.6). Patients with a 50% to 90% bladder capacity expected for age were more likely to benefit from therapy than those with a bladder capacity outside of this range. Age and gender were not significant predictors of resolution although girls were more likely to have resolution than boys. CONCLUSIONS: Idiopathic detrusor instability is amenable to conservative management in the majority of patients during a prolonged period. We advocate thorough urological and urodynamic evaluation to identify idiopathic detrusor instability as an etiology of enuresis and daytime wetting in complicated cases.

Dramatic rise in prostate-specific antigen after androgen replacement in a hypogonadal man with occult adenocarcinoma of the prostate.

We present the case of a hypogonadal patient in whom a 20-fold increase in prostate-specific antigen and a palpable prostatic nodule developed 6 months into the administration of intramuscular testosterone.

Retroperitoneoscopic technique for treating symptomatic caliceal diverticula.

Calculous disease in a caliceal diverticulum is a rare entity. The standard treatment currently is endoscopic surgery with marsupialization or fulguration or both with dilatation of the neck of the diverticulum. We present the fifth reported case of retroperitoneoscopic management of a caliceal diverticulum in a patient with a long history of flank pain and suggest that this treatment offers a stone-free rate comparable to that of open surgery with less morbidity than is associated with endoscopic treatments.

Diffuse large cell, B-cell type lymphoma with a novel translocation (2;22)(p23;q11.2).

We observed a translocation (2;22)(p23;q11.2) in the bone marrow cells of a patient with multiple subcutaneous nodules. Tumor histology and immunohistochemical staining demonstrated a malignant lymphoma, diffuse large cell type, displaying a CD30 negative B cell immunophenotype. To our knowledge, this is the first report of this specific translocation in lymphoma, which may join the site of the anaplastic lymphoma kinase (ALK) gene at 2p23 to the region of the immunoglobulin lambda light chain gene at 22q11.2. The ALK gene was initially identified through its involvement in the t(2;5)(p23;q35) found most commonly in anaplastic large cell lymphoma. This observation in a CD30 negative large cell lymphoma of B cell lineage further extends the relationship of anaplastic large cell morphology, ALK activation, lymphoid lineage, and expression of the CD30 antigen.

Exocytotic fusion pores exhibit semi-stable states.

Rapid-freezing/freeze-fracture electron microscopy and whole-cell capacitance techniques were used to study degranulation in peritoneal mast cells of the rat and the mutant beige mouse. These studies allowed us to create a time-resolved picture for fusion pore formation. After stimulation, a dimple in the plasma membrane formed a small contact area with the secretory granule membrane. Within this zone of apposition no ordered proteinaceous specializations were seen. Electrophysiological technique measured a small fusion pore which widened rapidly to 1 nS. Thereafter, the fusion pore remained at semi-stable conductances between 1 and 20 nS for a wide range of times, between 10 and 15,000 msec. These conductances correspond to pore diameters 25-36 nm. Ultrastructural data confirmed small pores of hourglass morphology, composed of biological membrane coplanar with both the plasma and granular membranes. Later, the fusion pore rapidly increased in conductance, consistent with the observed morphology of omega-figures. The hallmarks of channel-like behavior, instantaneous jumps in pore conductance between defined levels, and sharp peaks in histograms of conductance dwell-time, were not seen. Since the morphology of small pores shows contiguous fracture planes, the electrical data represent pores that contain lipid. These combined morphological and electrophysiological data are consistent with a lipid/protein complex mediating both the initial and later stages of membrane fusion.

Grand mal seizure in a postpartum patient following intravenous infusion of caffeine sodium benzoate to treat persistent headache.

A 27-year-old parturient developed a severe headache after placement of a labor epidural catheter. A presumptive diagnosis of an occult postdural puncture headache (PDPH) was made, and the patient was treated with an intravenous (IV) infusion of 500 mg of caffeine sodium benzoate (CSB) to vasoconstrict dilated cerebral vessels. Shortly after the infusion was completed, the patient experienced a self-limited grand mal seizure, which recurred later during her hospitalization. Despite a neurologic consultation and extensive testing, no definitive cause for the seizure was found. In light of the temporal relationship between caffeine use and the development of seizure activity, reports implicating caffeine's contribution to seizure activity, and evidence of a prolongation of the substance's half-life during and after pregnancy, we urge caution in the use of this drug in parturients.

Ionic control of the size of the vesicle matrix of beige mouse mast cells.

Isolated matrices of the giant secretory vesicles of mast cells of the beige mouse were reliably produced by the osmotic lysis of isolated vesicles. These matrices maintained their form, and their sizes were easily measured using Nomarski optics. The size of the matrix depended on the ionic composition of the bathing solution. The physiologically relevant ions, histamine and serotonin, contracted the matrix. Multivalent cations condensed the matrix relative to univalents. Ag+, acid pH (below 5), and basic pH (above 9) expanded the matrix. In the presence of 10 mM histamine, lowering the pH from 9 to 5 contracted the matrix more than can be attributed to the pH-dependent matrix contraction in zero histamine. The nontitratable organic cation, dimethonium, contracts the matrix with little effect of pH in the range of 5-9. These results suggest that histamine acts as a matrix contractor in the divalent form. The dose-response (contraction) relation for histamine was gradual from micromolar to 316 mM (millimolar) histamine. Experiments with mixtures of histamine and sodium show antagonistic effects on the matrix but are inconsistent with either a model where ions compete for identical sites or a parallel model where ions interact with separate independent sites. In vigorous histamine washoff experiments, the half time for vesicle expansion in 10(-4) M pH buffer was approximately 4 s; in isotonic NaCl solution, it was 0.5 s. When 1 M histamine was presented to closely apposed matrices, fusion resulted. The matrix material returned to its initial shape after being mechanically deformed with a glass probe. These results suggest that the matrix size is controlled by its ion exchange properties. The matrix expansion can quantitatively account for the vesicular size increase observed upon exocytosis (as a postfusional event) and the osmotic nonideality of intact vesicles. The mechanical expansion is probably significant in the widening of the exocytotic pore and the dispersal of the vesicular contents.

Options for labor analgesia: techniques of epidural and spinal analgesia.

The results of the clinical research evaluating techniques of labor analgesia suggest that drug combinations hold much promise for providing excellent analgesia for labor, while minimizing the adverse effects associated with each technique. With the various combinations of drugs and techniques available, the anesthesiologist is better able to customize the control of pain for each parturient.

Incidence of hypotension associated with epidural anesthesia using alkalinized and nonalkalinized lidocaine for cesarean section.

The onset of epidural anesthesia is accelerated by alkalinization of lidocaine with added epinephrine (LE). The possibility that decreases in systolic blood pressure (SBP) are also enhanced was studied in 21 patients having elective cesarean sections. Ten patients given LE + NaHCO3 (0.1 mEq/ml anesthetic solution) compared with 11 given LE alone had significantly (P less than 0.05) greater decreases in SBP (32% vs 19% from baseline values), as well as a greater rate of SBP decline to those minimum values (9%/min vs 3%/min, respectively). These differences were noted despite the fact that patients given LE + HCO3 received no less ephedrine and no more additional anesthetic than controls. Possible adverse effects of SBP reduction on uteroplacental blood flow suggest that caution be used in the use of alkalinized LE in obstetrical patients.

Onset and recovery of atracurium and suxamethonium-induced neuromuscular blockade with simultaneous train-of-four and single twitch stimulation.

Single twitch and train-of-four stimulation were applied at 0.08 Hz to each ulnar nerve and the force of contraction of the adductor pollicis was recorded during onset of and recovery from neuromuscular blockade by suxamethonium 1 mg kg-1 or atracurium 0.4 mg kg-1. Times to 90% first twitch blockade of train-of-four were (mean +/- SEM) 0.82 +/- 0.08 and 1.98 +/- 0.18 min for suxamethonium and atracurium, respectively, compared with times to 90% single twitch blockade of 1.00 +/- 0.07 and 3.35 +/- 0.37 min, respectively (P less than 0.05 in both cases). Apparent onset time also depended on how long train-of-four stimulation had been applied before injection of atracurium. The mode of stimulation had little effect on time to 10% recovery. The results are consistent with stimulation-induced augmentation in muscle blood flow, which increased delivery of the drug to the neuromuscular junction.

Effect of dietary silicon and aluminum on silicon and aluminum levels in rat brain.

This preliminary study was undertaken to investigate the effect of dietary silicon and aluminum on levels of these elements in brain. Two ages of rats, 22 day and 10 month, were assigned to 1 of 4 diets: 1) low silicon; 2) low silicon plus aluminum; 3) silicon supplemented; and 4) silicon supplemented plus aluminum. Rats were 23 and 28 months old upon termination of the experiment. Twelve brain regions were analyzed for silicon and aluminum. Regional variations in silicon, which were independent of dietary silicon supplementation, suggest that silicon may be an essential element in brain. Aluminum supplementation decreased the silicon content in selected brain regions, including those thought to be involved in Alzheimer disease. A relationship has been established between silicon, aluminum and age. In 23-month rats, aluminum supplementation did not increase brain aluminum content. By contrast, in 28-month rats, aluminum supplementation of the low silicon diet increased brain aluminum content in most regions. No increase occurred in silicon supplemented groups of the same age. Dietary silicon supplementation thus appeared to be protective against aluminum accumulation in aging brain.