De novo adamantinomatous craniopharyngioma with long-term pre-diagnostic imaging.

Adamantinomatous craniopharyngioma has a bimodal age distribution occurring in children aged 5-15 years and less frequently in adults aged 45-60 years. The current embryogenetic hypothesis suggests that adamantinomatous craniopharyngioma (ACP) arises from epithelial remnants of the craniopharyngeal duct or Rathke's pouch. It is thought that this tumor exists early on during childhood but remains indolent, growing very slowly until it is diagnosed incidentally or due to symptoms. Recent reports of de novo development of ACP, however, have challenged this theory. Herein, we present a case of an incidentally discovered de novo adamantinomatous craniopharyngioma that was documented to arise de novo on serial MRIs performed for a different indication. To our knowledge, this is the first report of a middle-aged patient who is diagnosed with a de novo ACP documented with contrast-enhanced MRIs of the sella over a 16-year period. This case challenges our current understanding of the pathophysiology of adamantinomatous craniopharyngioma.

Surgical anatomy of the anterior supralabyrinthine air cell tract.

INTRODUCTION: In order to safely explore the medial wall of the attic, a working knowledge of the anatomy of the anterior supralabyrinthine air cell tract is required. AIM: To clarify the surgically relevant anatomical relationships that comprise the anterior supralabyrinthine air cell tract. MATERIALS AND METHODS: Surgical dissection of 10 fresh cadaveric temporal bones was undertaken, including measurement of distances between the key anterior supralabyrinthine anatomical landmarks. RESULTS: The following mean distances were calculated: the labyrinthine segment between the geniculate ganglion and the ampullated end of the superior semicircular canal, 2.33 mm (range 1.75-2.75); the tympanic segment between the anterior margin of the oval window niche and the geniculate ganglion, 3.58 mm (range 3.25-4); and from the tympanic segment adjacent to the anterior margin of the oval window niche to the labyrinthine segment adjacent to the superior semicircular canal, 3.48 mm (range 3-4.25). CONCLUSION: The key anatomical landmarks of the anterior supralabyrinthine air cell tract define a distinct triangular segment of bone, knowledge of which is helpful in surgical dissection.

A planar elliptical model of cardio-vagal hysteresis.

The state-dependent portion of cardio-vagal baroreflex control is called baroreflex hyteresis: we observe hysteresis when RR interval and carotid diameter depend on both the direction and value of arterial pressure. The elasticity of arterial walls, as well as the responsiveness of central command reset controls the real-time pattern of neural outflow, which is indirectly measured by RR interval in humans. We model the state-dependent relationship among pressure, vessel diameter and heart rate as a three-dimensional planar ellipse. Two-dimensional projections of this ellipse provide motion direction and quantify hysteresis between mechanical (pressure-diameter), neural (diameter-heart rate), and integrated baroreflex (pressure-heart rate) components. A convenient measure for the magnitude of hysteresis is the ratio of the semi-minor and semi-major axes of the best fitting ellipse. This ratio is given a sign according to the direction of its motion. The signed sum of the hysteresis ratio for vessel mechanics and central neural control reliably predicts cardio-vagal hysteresis. Using this relationship, we can quantify the relative importance of neural versus mechanical contributions to integrated baroreflex responses.

Noise exposure and hearing loss prevention programmes after 20 years of regulations in the United States.

OBJECTIVES: To evaluate noise exposures and hearing loss prevention efforts in industries with relatively high rates of workers' compensation claims for hearing loss. METHODS: Washington State workers' compensation records were used to identify up to 10 companies in each of eight industries. Each company (n = 76) was evaluated by a management interview, employee personal noise dosimetry (n = 983), and employee interviews (n = 1557). RESULTS: Full-shift average exposures were > or =85 dBA for 50% of monitored employees, using Occupational Safety and Health Administration (OSHA) parameters with a 5 dB exchange rate (L(ave)), but 74% were > or =85 dBA using a 3 dB exchange rate (L(eq)). Only 14% had L(ave) > or =90 dBA, but 42% had L(eq) > or =90 dBA. Most companies conducted noise measurements, but most kept no records, and consideration of noise controls was low in all industries. Hearing loss prevention programmes were commonly incomplete. Management interview scores (higher score = more complete programme) showed significant associations with percentage of employees having L(ave) > or =85 dBA and presence of a union (multiple linear regression; R2 = 0.24). Overall, 62% of interviewed employees reported always using hearing protection when exposed. Protector use showed significant associations with percentage of employees specifically required to use protection, management score, and average employee time spent > or =95 dBA (R2 = 0.65). CONCLUSIONS: The findings raise serious concerns about the adequacy of prevention, regulation, and enforcement strategies in the United States. The percentage of workers with excessive exposure was 1.5-3 times higher using a 3 dB exchange rate instead of the OSHA specified 5 dB exchange rate. Most companies gave limited or no attention to noise controls and relied primarily on hearing protection to prevent hearing loss; yet 38% of employees did not use protectors routinely. Protector use was highest when hearing loss prevention programmes were most complete, indicating that under-use of protection was, in some substantial part, attributable to incomplete or inadequate company efforts.

Self-reported musculoskeletal symptoms and observed risk factors in bareroot tree nurseries.

A cross-sectional study of jobs at four bareroot reforestation tree nurseries in Washington and Oregon investigated the prevalence of musculoskeletal symptoms and potential work-related musculoskeletal disorders (WMSDs), and analyzed their association with physical and psychosocial risk factors of the jobs. Questionnaires were used to assess symptoms and psychosocial factors. Direct observational work sampling was utilized to estimate physical risk factors. The response rate for the questionnaires was 41% (203 subjects), of which 72% reported recurring symptoms in the past year. The most common body region was the wrist/hand (42%). Pain was the most commonly reported symptom. Forty-one percent of the subjects had at least one potential WMSD, the hand region having the greatest number of cases (n = 51). The average age of those with and without potential WMSDs did not significantly differ; however, tenure at the nursery (p < 0.03) did. Being female (OR = 7.37; 95% CI = 2.75, 19.7,) high job satisfaction (OR = 0.32; 95% CI = 0.15, 0.72), and having a second job (OR = 3.76; 95% CI = 1.12, 12.57) were significantly associated with potential WMSDs. No significant difference in WMSD prevalence was found between the field and packing shed areas of the nurseries (p = 0.88). Pinch gripping was observed 24% of the time in the shed and 8% of the time in the field. Torso flexion was observed more often in the field than the shed (38% vs. 18% of the time). This study found that both physical and psychosocial factors associated with WMSDs are present in bareroot trees nurseries.

Dynamics of reversible supramolecular polymers: independent determination of the dependence of linear viscoelasticity on concentration and chain length by using chain stoppers.

The linear viscoelasticity of solutions of a hydrogen bonded reversible supramolecular polymer in the presence of a chain stopper was studied by rheometry and by dynamic light scattering using probe particles. The use of chain stoppers enabled the independent variation of the degree of polymerisation and the monomer concentration, and the effect of both parameters on rheology was investigated. Scaling exponents were obtained for the chain length and concentration dependence of the zero-shear viscosity and the terminal relaxation time, and these were compared to theoretical values. The results indicate that the reversible supramolecular polymer is semiflexible, and that both breaking and reptation of chains contribute to the stress relaxation. The parameters from macroscopic rheometry were compared to microscopic values obtained from probe particle diffusion. The particles probe the macroscopic viscoelastic parameters if their size is large compared to the correlation length in the system and to the (persistence) length of the polymer chains.

Pancreatic polypeptide reduces appetite and food intake in humans.

Pancreatic polypeptide (PP) is a gut hormone released from the pancreas in response to ingestion of food. Plasma PP has been shown to be reduced in conditions associated with increased food intake and elevated in anorexia nervosa. In addition peripheral administration of PP has been shown to decrease food intake in rodents. These findings suggest that PP may act as a circulating factor that regulates food intake. Therefore we investigated the effect of intravenous infusion of PP (10 pmol/kg/min) on appetite and food intake in a randomised double-blind placebo-controlled crossover study in ten healthy volunteers. Infusion of PP reduced appetite and decreased the energy intake at a buffet lunch two hours post-infusion by 21.8 +/- 5.7% (P < 0.01). More importantly the inhibition of food intake was sustained, such that energy intake, as assessed by food diaries, was significantly reduced both the evening of the study and the following morning. Overall PP infusion reduced cumulative 24-hour energy intake by 25.3 +/- 5.8%. In conclusion our data demonstrates that PP causes a sustained decrease in both appetite and food intake.

The effect of fibrolytic enzymes sprayed onto forages and fed in a total mixed ratio to lactating dairy cows.

We investigated the effect of spraying different combinations of fibrolytic enzymes onto forages on their nutritive value for lactating cows. Holstein cows were fed a TMR consisting of 30% corn silage, 15% alfalfa hay, and 55% concentrate (dry matter basis). During a 12-wk treatment period, the forages were treated with no enzymes (control), cellulase D and sultanas B, or cellulase D and xylanase C. Enzymes were diluted in water and sprayed onto the forages while mixing. Both combinations of enzymes supplied similar amounts of fibrolytic activity based on classical enzyme assays conducted at 50 degrees C. Cows fed forages treated with cellulase D and xylanase B tended to produce more 3.5% FCM (+2.5 kg/d) than did cows fed the untreated forages. Dry matter intake, milk production, milk fat, and milk protein were unaffected by treatment. In vitro production of gas from forages treated with enzymes was greater than from untreated forage, but 96-h volatile fatty acid production was not different among treatments. With an alternative enzyme assay based on the depolymerization of dyed substrate at 40 degrees C, activity of xylanase C was greatest at a pH of 6.5 but was substantially reduced as the pH of the assay was decreased. In contrast, xylanase B showed highest activity at pH 5 and enzyme activity was twice that of xylanase B at pH 5.5 and 6. Overall, the results of this study provide more evidence that fibrolytic enzymes can be used to improve milk production in lactating cows.

Chronic intraparaventricular nuclear administration of orexin A in male rats does not alter thyroid axis or uncoupling protein-1 in brown adipose tissue.

Orexin A, synthesised in the posterolateral hypothalamus, has widespread distribution including the paraventricular nucleus (PVN), which is rich in thyrotropin-releasing hormone (TRH) neurones. Nerve fibres in the PVN synapse on neurones that send polysynaptic projections to brown adipose tissue (BAT), which is important in thermogenesis. A number of observations suggests orexin A may be involved in regulation of metabolism and thermogenesis. We investigated the effect of orexin A injected intracerebroventricularly (ICV) on thyroid-stimulating hormone (TSH) and thyroid hormones in male rats. We then examined the effect of chronic iPVN injections of orexin A on plasma TSH and uncoupling protein-1 (UCP-1) protein in BAT. Orexin A (3 nmol) administered ICV significantly suppressed plasma TSH at 10 and 90 min. Orexin A (0.3 nmol) administered into the PVN twice daily for 3 days significantly increased day-time 2-h food intake, but did not significantly alter nocturnal food intake. Though chronic iPVN orexin A altered diurnal food intake, there was no effect on 24-h food intake or body weight. Furthermore, orexin A administered chronically into the PVN did not alter UCP-1 level in BAT, or plasma hormones relative to saline injected animals. Chronic iPVN orexin A does not appear to influence thermogenesis through activation of UCP-1 or the thyroid axis.

Ghrelin enhances appetite and increases food intake in humans.

Ghrelin is a recently identified endogenous ligand for the growth hormone secretagogue receptor. It is synthesized predominantly in the stomach and found in the circulation of healthy humans. Ghrelin has been shown to promote increased food intake, weight gain and adiposity in rodents. The effect of ghrelin on appetite and food intake in man has not been determined. We investigated the effects of intravenous ghrelin (5.0 pmol/kg/min) or saline infusion on appetite and food intake in a randomised double-blind cross-over study in nine healthy volunteers. There was a clear-cut increase in energy consumed by every individual from a free-choice buffet (mean increase 28 +/- 3.9%, p<0.001) during ghrelin compared with saline infusion. Visual analogue scores for appetite were greater during ghrelin compared to saline infusion. Ghrelin had no effect on gastric emptying as assessed by the paracetamol absorption test. Ghrelin is the first circulating hormone demonstrated to stimulate food intake in man. Endogenous ghrelin is a potentially important new regulator of the complex systems controlling food intake and body weight.

Should a psychiatrist report a bus driver's alcohol and drug abuse? An ethical dilemma.

Denial of alcohol or drug abuse, and of its possible consequences, can complicate medical and psychiatric care. We present the case of an HIV-positive bus driver with substance abuse who initially denied ongoing use of alcohol and of other drugs, but later admitted to both. The psychiatrist's duty to protect the patient's confidentiality, coupled with concerns about public safety, created an ethical dilemma. In discussing this dilemma we stress the importance of preserving confidentiality, both to facilitate treatment and also to further the safety of others.

Recombinant human platelet-derived growth factor gel speeds healing of acute full-thickness punch biopsy wounds.

BACKGROUND: Recombinant human platelet derived growth factor-BB gel (PDGF gel) has been shown to be effective in the treatment of diabetic neuropathic ulcers. It is also being used off-label to speed wound healing of flaps, grafts, and wounds from Mohs micrographic surgery. OBJECTIVE: The purpose of the study was to compare the rate of healing in wounds treated with PDGF gel and with wounds treated with conventional therapy (antibiotic ointment). METHODS: A double-blind controlled study of 7 healthy volunteers was performed. With a 4-mm skin punch biopsy instrument, two full-thickness wounds were made on each arm of each volunteer. Fourteen wounds treated with PDGF gel were compared with 14 wounds treated with antibiotic ointment. Healing was evaluated by visual determination of the global percentage healed and wound depth. RESULTS: Wounds treated with PDGF gel showed a significantly faster rate of healing on each of the initial 6 follow-up visits. The greatest difference was on day 10 when PDGF-treated wounds were 71% healed compared with 28% for antibiotic-treated wounds (P =.0005). At days 22 and 24, 92.9% and 100% of the PDGF gel-treated wounds were healed, compared with 50% and 57%, respectively (P =.0313 and P =.0313), in the antibiotic ointment group. By day 29, both PDGF gel and antibiotic-treated wounds were healed. PDGF also decreased wound depth compared with wounds treated with antibiotic ointment at days 8 and 10 with P values <.0313 and <.0020, respectively. CONCLUSION: We conclude that PDGF gel speeds healing of acute full-thickness wounds compared with antibiotic ointment.

Ghrelin causes hyperphagia and obesity in rats.

Ghrelin, a circulating growth hormone-releasing peptide derived from the stomach, stimulates food intake. The lowest systemically effective orexigenic dose of ghrelin was investigated and the resulting plasma ghrelin concentration was compared with that during fasting. The lowest dose of ghrelin that produced a significant stimulation of feeding after intraperitoneal injection was 1 nmol. The plasma ghrelin concentration after intraperitoneal injection of 1 nmol of ghrelin (2.83 +/- 0.13 pmol/ml at 60 min postinjection) was not significantly different from that occurring after a 24-h fast (2.79 +/- 0.32 pmol/ml). After microinjection into defined hypothalamic sites, ghrelin (30 pmol) stimulated food intake most markedly in the arcuate nucleus (Arc) (0-1 h food intake, 427 +/- 43% of control; P < 0.001 vs. control, P < 0.01 vs. all other nuclei), which is potentially accessible to the circulation. After chronic systemic or intracerebroventricular (ICV) administration of ghrelin for 7 days, cumulative food intake was increased (intraperitoneal ghrelin 13.6 +/- 3.4 g greater than saline-treated, P < 0.01; ICV ghrelin 19.6 +/- 5.5 g greater than saline-treated, P < 0.05). This was associated with excess weight gain (intraperitoneal ghrelin 21.7 +/- 1.4 g vs. saline 10.6 +/- 1.9 g, P < 0.001; ICV ghrelin 15.3 +/- 4.3 g vs. saline 2.2 +/- 3.8 g, P < 0.05) and adiposity. These data provide evidence that ghrelin is important in long-term control of food intake and body weight and that circulating ghrelin at fasting concentrations may stimulate food intake.

A model for the genesis of arterial pressure Mayer waves from heart rate and sympathetic activity.

Both theoretic models and cross-spectral analyses suggest that an oscillating sympathetic nervous outflow generates the low-frequency arterial pressure fluctuations termed Mayer waves. Fluctuations in heart rate also have been suggested to relate closely to Mayer waves, but empiric models have not assessed the joint causative influences of heart rate and sympathetic activity. Therefore, we constructed a model based simply upon the hemodynamic equation derived from Ohm's Law. With this model, we determined time relations and relative contributions of heart rate and sympathetic activity to the genesis of arterial pressure Mayer waves. We assessed data from eight healthy young volunteers in the basal state and in a high sympathetic state known to produce concurrent increases in sympathetic nervous outflow and Mayer wave amplitude. We fit the Mayer waves (0.05-0.20 Hz) in mean arterial pressure by the weighted sum of leading oscillations in heart rate and sympathetic nerve activity. This model of our data showed heart rate oscillations leading by 2-3.75 s were responsible for almost half of the variance in arterial pressure (basal R2 = 0.435 +/- 0.140, high sympathetic R2= 0.438 +/- 0.180). Surprisingly, sympathetic activity (lead 0-5 s) contributed only modestly to the explained variance in Mayer waves during either sympathetic state (basal: delta R2 = 0.046 +/- 0.026; heightened: delta R2 = 0.085 +/- 0.036). Thus, it appears that heart rate oscillations contribute to Mayer waves in a simple linear fashion, whereas sympathetic fluctuations contribute little to Mayer waves in this way. Although these results do not exclude an important vascular sympathetic role, they do suggest that additional factors, such as sympathetic transduction into vascular resistance, modulate its influence.

Controlled ovarian hyperstimulation. Relationship of early serum E2 levels to the ultimate response of oocyte donors.

OBJECTIVE: To assess the predictive value of measuring serum day 5 E2 and in vitro fertilization (IVF) cycle outcome of oocyte donors undergoing controlled ovarian hyperstimulation (COH). STUDY DESIGN: Retrospective data analysis. RESULTS: Day 5 E2 significantly correlated with the peak serum E2 and number of retrieved mature oocytes. The pregnancy rates associated with stimulated day 5 E2 > 70 pg/mL were significantly greater than in cycles with levels < 70 pg/mL (58%, 71/123, versus 25%, 15/60; P < .05). CONCLUSION: The cycle performance of an oocyte donor can be predicted by measuring cycle day 5 serum E2 during COH. Poor-prognosis cycles can be identified and discontinued, saving patients and the program unnecessary exspense.

Laryngopharyngeal sensory deficits as a predictor of aspiration.

OBJECTIVE: This study evaluates whether patients with severe sensory deficits in the hypopharynx are at increased risk for aspiration and determines the relationship between pharyngeal muscular weakness and hypopharyngeal sensory deficits. STUDY DESIGN AND SETTING: Forty patients with dysphagia who underwent flexible endoscopic evaluation of swallowing with sensory testing were prospectively divided into 2 groups. One group included patients with severe sensory deficits determined by an absent laryngeal adductor reflex and the other with normal sensitivity. Subjects were given liquid and puree consistencies and were evaluated for aspiration as well as pharyngeal muscle contraction. RESULTS: The differences in incidence of aspiration and pharyngeal muscular weakness between the 2 groups were significant (P < 0.001 Fisher's exact test). CONCLUSION: There is a strong association between motor function deficits and hypopharyngeal sensory deficits. SIGNIFICANCE: The association of sensory loss and motor deficits together with the use of flexible endoscopic evaluation of swallowing with sensory testing can predict those patients who are at highest risk for aspiration.