Pathology of the Olfactory Epithelium: Smoking and Ethanol Exposure

OBJECTIVE

To investigate the effects of tobacco smoke on the olfactory epithelium. Cigarette smoking has been associated with hyposmia; however, the pathophysiology is poorly understood. The sense of smell is mediated by olfactory sensory neurons (OSNs) exposed to the nasal airway, rendering them vulnerable to environmental injury and death. As a consequence, a baseline level of apoptotic OSN death has been demonstrated even in the absence of obvious disease. Dead OSNs are replaced by the mitosis and maturation of progenitors to maintain sufficient numbers of neurons into adult life. Disruption of this balance has been suggested as a common cause for clinical smell loss. This current study will evaluate the effects of tobacco smoke on the olfactory mucosa, with emphasis on changes in the degree of OSN apoptosis.

STUDY DESIGN

A rat model was used to assess the olfactory epithelium after exposure to tobacco smoke.

METHODS

Rats were exposed to tobacco smoke alone (for 12 weeks), smoke plus dietary ethanol (for the final 5 weeks), or to neither (control). Immunohistochemical analysis of the olfactory epithelium was performed using an antibody to the active form of caspase-3. Positive staining for this form of the caspase-3 enzyme indicates a cell undergoing apoptotic proteolysis.

RESULTS

Control rats demonstrated a low baseline level of caspase-3 activity in the olfactory epithelium. In contrast, tobacco smoke exposure triggered a dramatic increase in the degree of OSN apoptosis that affected all stages of the neuronal lineage.

CONCLUSIONS

These results support the following hypothesis: smell loss in smokers is triggered by increased OSN death, which eventually overwhelms the regenerative capacity of the epithelium.

Sleep problems in children with an intellectual disability: parental perceptions of sleep problems, and views of treatment effectiveness

BACKGROUND

Sleep problems are common in children with an intellectual disability (ID), often lasting for many years. Many parents do not perceive their child to have a sleep problem, do not believe treatment is possible and do not seek treatment. This paper examined prevalence and duration of sleep problems in children with an ID and considered parental perceptions of sleep problems and views towards treatment.

METHOD

The paper reports on two studies (n = 149 and 243 respectively) of children between 3 and 18 years, with a range of disabilities. Parents in each study completed a questionnaire about their child's sleep problems, and the type and effectiveness of any treatment used to address their child's sleep problems.

RESULTS

Prevalence rates ranged between 25.5% and 36.2% for sleep problems with an average duration of between 6 and 9 years. Around half of parents had sought treatment for their child's sleep problem in Study 1, while 76% had done so in Study 2. Parental ratings regarding treatment effectiveness were higher in Study 1 than in Study 2. Contrary to expectations, behavioural treatment was not rated as significantly more effective than other treatments in either study.

CONCLUSIONS

While sleep problems are common and chronic in children with an ID, parents may not recognize a sleep problem as present, often do not seek treatment for their child's sleep problems, and treatment advice and effectiveness is very variable. Thus, further research and parent and professional education regarding the identification and treatment of sleep problems in these children is required.

Sleep problems in children with an intellectual disability: parental perceptions of sleep problems, and views of treatment effectiveness

BACKGROUND

Sleep problems are common in children with an intellectual disability (ID), often lasting for many years. Many parents do not perceive their child to have a sleep problem, do not believe treatment is possible and do not seek treatment. This paper examined prevalence and duration of sleep problems in children with an ID and considered parental perceptions of sleep problems and views towards treatment.

METHOD

The paper reports on two studies (n = 149 and 243 respectively) of children between 3 and 18 years, with a range of disabilities. Parents in each study completed a questionnaire about their child's sleep problems, and the type and effectiveness of any treatment used to address their child's sleep problems.

RESULTS

Prevalence rates ranged between 25.5% and 36.2% for sleep problems with an average duration of between 6 and 9 years. Around half of parents had sought treatment for their child's sleep problem in Study 1, while 76% had done so in Study 2. Parental ratings regarding treatment effectiveness were higher in Study 1 than in Study 2. Contrary to expectations, behavioural treatment was not rated as significantly more effective than other treatments in either study.

CONCLUSIONS

While sleep problems are common and chronic in children with an ID, parents may not recognize a sleep problem as present, often do not seek treatment for their child's sleep problems, and treatment advice and effectiveness is very variable. Thus, further research and parent and professional education regarding the identification and treatment of sleep problems in these children is required.

Pathology of the Olfactory Mucosa: Implications for the Treatment of Olfactory Dysfunction

OBJECTIVE

The pathology of the olfactory mucosa is poorly understood; however, most cases of hyposmia and anosmia appear to be associated with a decline in the number of functioning mature olfactory sensory neurons (OSNs). Under normal conditions, OSNs undergo apoptotic cell death at a baseline rate likely secondary to their exposed location in the nose. Regeneration of mature OSNs from precursors in the epithelium allows the animal to maintain an adequate number of neurons necessary for olfactory sensation. In many cases of olfactory dysfunction, this balance is apparently disturbed, with a net loss of OSNs. The current study will examine normal and diseased olfactory tissue for the presence of data demonstrating that the preferred mechanism of OSN cell death is apoptotic in both health and disease. The potential therapeutic implications will be discussed.

STUDY DESIGN

Histologic analysis of human and animal olfactory tissue.

METHODS

Normal and diseased human and animal olfactory mucosa were assessed for immunohistochemical evidence of apoptosis.

RESULTS

Increased activity of the apoptotic effector enzyme caspase-3 was demonstrated in diseased olfactory mucosa in comparison with normal controls.

CONCLUSION

These results indicate that a common pathway may mediate OSN cell death from a diverse set of pathologic insults including aging, trauma, and sinusitis. Interference with this pathway of cell death is currently the subject of intense pharmacotherapeutic research for the management of stroke and meningitis. These drugs may ultimately prove useful in the treatment of clinical olfactory dysfunction.

Screening for diabetes in general practice: cross sectional population study

OBJECTIVE

To assess the policy proposed by the American Diabetes Association of universal screening in general practice of all patients aged over 45 years for diabetes.

DESIGN

Cross sectional population study.

SETTING

Local general practice in the United Kingdom.

PARTICIPANTS

All patients aged over 45 not known to have diabetes.

MAIN OUTCOME MEASURES

Prevalence of diabetes in the screened population, cardiovascular risk profile of patients diagnosed as having diabetes after screening.

RESULTS

Of 2481 patients aged over 45 and not known to have diabetes, 876 attended for screening. There were no significant demographic differences between the screened and unscreened patients. Prevalence of diabetes in patients with age as a sole risk factor was 0.2% (95% confidence interval 0% to 1.4%). Prevalence of diabetes in patients with age and one or more other risk factors (hypertension, obesity, or a family history of diabetes) was 2.8% (1.6% to 4.7%). Four hours a week for a year would be needed to screen all people over 45 in the practice's population; about half this time would be needed to screen patients with risk factors other than age. More than 80% of patients newly diagnosed as having diabetes had a 10 year risk of coronary heart disease >15%, 73% (45% to 92%) were hypertensive, and 73% (45% to 92%) had a cholesterol concentration >5 mmol/l.

CONCLUSIONS

Screening for diabetes in general practice by measuring fasting blood glucose is feasible but has a very low yield in patients whose sole risk factor for diabetes is age over 45. Screening in a low risk population would best be targeted at patients with multiple risk factors.

The use of immunoliposomes for specific delivery of antimicrobial agents to oral bacteria immobilized on polystyrene

Antibacterial immunoliposomes have been prepared using covalently bound antibody, raised to the cell surface of the bacterium Streptococcus oralis (S. oralis), and incorporating the bactericides chlorhexidine and Triclosan. A regrowth assay, in which the ability of a bacterial biofilm immobilised on polystyrene to grow after exposure to a test solution, was undertaken to study the action of the antibacterial immunoliposomes. The antibacterial anti-oralis immunoliposomes show enhanced growth inhibition of S. oralis, compared to free bactericide, using low bactericide concentrations. For short exposure times to the biofilms, antibacterial anti-oralis immunoliposomes can show several times enhanced growth inhibition of S. oralis compared to free bactericide. Antibacterial anti-oralis immunoliposomes inhibit the growth of S. oralis more than that of other oral bacteria. The extent of growth inhibition by antibacterial anti-oralis immunoliposomes is linearly related to the number of immunoliposomes targeted to the biofilm surface.

Expression of nitric oxide synthase type 3 in reflux-induced esophageal lesions

BACKGROUND

The expression of endothelial constitutive nitric oxide synthase (NOS3) by squamous dysplasia and carcinomas of the head and neck has previously been described. We sought to compare NOS3 expression in squamous mucosa, glandular metaplasia, and adenocarcinoma of the esophagus.

METHODS

Forty paraffin-embedded specimens from 20 patients with adenocarcinoma were stained with anti-NOS3 monoclonal antibody. The percentage of cells stained and the intensity of staining were determined for squamous epithelium, metaplasia, and adenocarcinoma. Staining characteristics were statistically analyzed according to clinical variables.

RESULTS

NOS3 expression was significantly higher in adenocarcinoma and squamous epithelium compared with glandular metaplasia. Among the carcinomas, larger tumor size (T3/4), nodal positivity, and advanced TNM stage (III/IV) significantly correlated with increased NOS3 expression.

CONCLUSIONS

NOS3 is expressed in reflux-induced lesions of the esophagus. Glandular metaplasia shows basal levels of NOS3 that significantly increase with malignant transformation and tumor progression. The role of free radicals in carcinogenesis is being actively studied.

Mineralocorticoid receptors in the mammalian olfactory mucosa

Mineralocorticoid hormones regulate secretion and absorption in a wide variety of epithelial tissues, although specific mechanisms in the olfactory mucosa are currently unknown. Utilizing reverse transcription-polymerase chain reaction (RT-PCR) analysis, we have demonstrated the expression of mineralocorticoid (type I) receptor messenger RNA in the rodent olfactory mucosa. Amplification products of predicted size were obtained with nucleotide sequences corresponding to respective mineralocorticoid receptor (MR) kidney transcripts. Immunocytochemistry, using an antibody with known specificity for MRs, was then utilized in order to localize the cellular site(s) of MR protein expression in the olfactory mucosa. The highest levels of MR immunoreactivity were localized to the supranuclear region of sustentacular cells, as well as the acinar cells of the Bowman's glands. The respiratory regions of the nasal cavity were devoid of appreciable MR immunoreactivity. This study demonstrates both MR transcript and protein expression in the olfactory mucosa. We hypothesize that the mineralocorticoid hormones may have a role in modulation of olfactory secretion and/or sensory transduction in the peripheral olfactory system.

Expression of gamma-aminobutyric acid(A) receptor subunits in the vestibular system

OBJECTIVES

Profile the expression of genes encoding GABAA receptor subunits in the vestibular end organs of a rat.

MATERIALS AND METHODS

Using a combination of reverse transcription followed by polymerase chain reaction (PCR) with gene-specific primers, expression of mRNAs encoding 13 individual GABA(A) receptor subunits was examined.

RESULTS

PCR amplification products representing subunit gene expression for alpha1-6, beta1-3, and gamma1-3, but not for delta, subunits were amplified, suggesting multiple molecular levels of regulation of vestibular GABA(A) receptor expression. Nucleotide sequencing confirmed the identity of rat vestibular end-organs subunit cDNAs.

CONCLUSION

These results give the most direct evidence to date that GABAA receptors composed of the detected subunits are expressed in the mammalian vestibular system, giving new support to previous investigations implicating GABA as a vestibular neurotransmitter.

Expression of glucocorticoid receptor mRNA and protein in the olfactory mucosa: physiologic and pathophysiologic implications

OBJECTIVES

Define the presence and distribution of glucocorticoid receptors (GRs) within the olfactory mucosa in order to assess potential physiologic and pathophysiologic effects of these hormones on olfaction.

STUDY DESIGN

The olfactory mucosa was harvested from adult male rats and guinea pigs. Kidney tissue was utilized as a known positive control.

METHODS

The techniques of reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry were utilized to examine the expression of GR mRNA and protein. To assure the presence of olfactory mucosa in the nasal tissue samples, RT-PCR was utilized to identify the olfactory marker protein (OMP).

RESULTS

The presence of GR mRNA was confirmed in both the olfactory mucosa and kidney. GR-like immunoreactivity associated with the olfactory epithelium was greatest at the apical surface, a position corresponding to the dendrites, knobs, and cilia of olfactory receptor neurons, as well as the supranuclear region of sustentacular cells. Weaker GR-like immunoreactivity was associated with the region of the cell bodies of the olfactory receptor neurons. Within the lamina propria, acinar cells of the Bowman's glands and olfactory nerve bundles were intensely immunoreactive.

CONCLUSIONS

The presence of GR mRNA and protein within the olfactory mucosa is consistent with a functional role for glucocorticoid hormones in the systemic regulation of olfaction. Furthermore, these studies suggest that corticosteroid medications may have direct effects on the cells of the olfactory mucosa in the pathologic state. The potential mechanisms whereby these hormones may act are discussed.

The specificity and affinity of immunoliposome targeting to oral bacteria

Immunoliposomes have been prepared using antibodies raised to an antigenic determinant on the cell surface of the oral bacterium Streptococcus oralis (S. oralis) in an investigation of their potential to reduce dental plaque. The N-succinimidyl-S-acetylthioacetate (SATA) derivative of the antibodies were conjugated through the reactive m-maleimidobenzoyl-N-hydroxysuccinimide (MBS) derivative of dipalmitoyl-phosphatidylethanolamine (DPPE) incorporated into liposomes. The degree of antibody conjugation to the liposomes was controlled by the percentage of DPPEMBS incorporated into the liposomes. The chemical modification of the antibodies did not affect the ability of the antibodies to bind to a S. oralis biofilm. However, the affinity of the immunoliposomes for S. oralis was much lower than that of the free antibody. The anti-oralis antibodies were highly specific for S. oralis. The anti-oralis immunoliposomes showed the greatest affinity for S. oralis, when targeted to a range of different oral bacterial biofilms. The immunoliposome targeting affinity for S. oralis was largely unaffected by the number of antibodies conjugated to the liposomal surface or by the net charge of the liposomal lipid bilayer. The immunoliposomes showed a greater affinity for S. oralis than 'naked' (bearing no antibody) liposomes. However, positively charged liposomes, incorporating stearylamine, adsorbed to S. oralis with greater affinities than the immunoliposomes. The immunoliposomes appeared to be physically stable over a period of 18 months, as judged by particle-size measurements.

Impotence in diabetes

Impotence is more common in diabetic patients than in the normal population. This is due to the complications of diabetes, which damage the neurovascular bundle required for normal penile function. Minimally invasive methods of treatment have improved the outcome; however, the methods are still suboptimal. Recent advances in our understanding of the underlying mechanisms may lead to more non-invasive, targeted forms of treatment. (Trends Endocrinol Metab 1997;8:98-101). (c) 1997, Elsevier Science Inc.

Glucocorticoid replacement therapy: are patients over treated and does it matter?

BACKGROUND AND OBJECTIVES

Adequate assessment of patients on glucocorticoid replacement therapy is of great importance to avoid the consequences of under or over treatment, but no simple test is available for this. The aims of this study were (1) to assess adequacy of glucocorticoid replacement in hypoadrenal patients, (2) to correlate serum cortisol levels (cortisol day curve) with 24-hour urine free cortisol excretion and (3) to assess the impact of glucocorticoid dose optimization on markers of bone formation and bone resorption.

DESIGN

Cross-sectional study of current replacement therapy and a prospective study of the effect of dose alteration on bone turnover markers.

PATIENTS

Thirty-two consecutive patients on replacement glucocorticoid therapy (12 Addison's disease, 20 hypopituitarism) from a University teaching hospital out-patient department.

MEASUREMENTS

Serum and urinary cortisol, osteocalcin, N-telopeptide of type I collagen (NTX) and bone mineral density.

RESULTS

28/32 (88%) patients required a change of therapy; 24/32 (75%) a total reduction in dose, 18/32 (56%) a change in replacement therapy regimen or drug and 14/32 (44%) both changes. The mean daily dose of hydrocortisone was reduced from 29.5 +/- 1.2 to 20.8 +/- 1.0 mg. A significant correlation was found between peak cortisol and 24-hour urine free cortisol/ creatinine (Spearman correlation r = 0.60, P < 0.0001; n = 51). Following hydrocortisone dose reduction, median osteocalcin increased from 16.7 micrograms/l (range 8.2-65.7) to 19.9 micrograms/l (8.2-56.3); P < 0.01, with no change in the NTX/creatinine ratio.

CONCLUSIONS

A high proportion of patients on conventional corticosteroid replacement therapy are over treated or on inappropriate replacement regimens. To reduce the long term risk of osteoporosis, corticosteroid replacement therapy should be individually assessed and over replacement avoided.

Diverticulitis. A comprehensive follow-up

PURPOSE

This study was undertaken to examine the longterm results of medical and surgical management for diverticulitis.

METHODS

A retrospective review of all patients admitted to Naval Medical Center Portsmouth, Virginia, between January 1991 and February 1994, was conducted. Of 78 patients included in the study, 65 were able to be contacted for follow-up.

RESULTS

The surgically treated group consisted of 33 patients, and medically treated group had 32 patients. Of the medically treated group, 62.5 percent were found to have continuing symptoms. Medically treated patients with a long history and infrequent flares tended to be less symptomatic after hospitalization. Conversely, those medical patients with a short intense history were more likely to have symptoms. The frequency of symptoms in the surgical group was surprising, because 27.2 percent of this group reported continuing symptoms.

CONCLUSIONS

Close follow-up of medically treated patients for objective evidence of diverticulitis is indicated. When surgical therapy is undertaken, patients should be counseled that symptoms may be largely unchanged following operation.

Antecedent hypoglycaemia in non-diabetic subjects reduces the adrenaline response for 6 days but does not affect the catecholamine response to other stimuli

1. Recent hypoglycaemia reduces the counter-regulatory and symptomatic response to the next episode of hypoglycaemia. This study was designed to determine whether antecedent hypoglycaemia (a) affected the sympathoadrenal response to other stimuli (postural change and a mathematical stress test, (b) was associated with adaptation of cognitive function and (c) if avoided for 6 days led to the restoration of the counter-regulatory response to hypoglycaemia. 2. On the morning of day 1, 10 healthy men had their response to the sympathoadrenal stimuli assessed before an episode of hypoglycaemia (2.5 mmol/l). A further hyperinsulinaemia clamp was performed for 2h (blood glucose 3.0 mmol/l or 5.0 mmol/l) in the afternoon and the assessments repeated the next day and 6 days later. Cognitive function using the four-choice reaction time test was assessed before and during the episodes of morning hypoglycaemia. The whole study was repeated 4 weeks later with the other afternoon glucose level. 3. Adrenaline levels and sweat rates were reduced (P < 0.05) on day 2 during hypoglycaemia on both occasions and had not returned to normal after 6 days. Symptom scores were lower (P < 0.05) only on day 2 after the afternoon of hypoglycaemia. The responses to the sympathoadrenal stimuli and cognitive function were unaffected by antecedent hypoglycaemia. 4. The adaptation of the counter-regulatory response to antecedent hypoglycaemia appears to be specific to hypoglycaemia. The response takes longer than 6 days but less than 4 weeks to return to normal. Antecedent hypoglycaemia does not lead to cerebral adaptation.

Physiological response to postural change during mild hypoglycaemia in patients with IDDM

It has been suggested that patients with insulin-dependent diabetes mellitus may be less aware of impending hypoglycaemia when lying than standing. We have studied the effect of posture and duration of hypoglycaemia on symptoms and physiological responses in 10 men with insulin-dependent diabetes. A standard tilting protocol was used (supine, 50 degrees, 90 degrees headup, and return to supine, 5 min at each position). At one visit patients were tilted before, 10 min after and 40 min after achieving hypoglycaemia (blood glucose 2.5 mmol/l), and at another visit were tilted after euglycaemia (5.0 mmol/l) using a hyperinsulinaemic clamp. At each position, hormonal and physiological responses and symptoms (using visual analogue scales) were recorded. After 10 min of hypoglycaemia, adrenaline was significantly higher when 90 degrees headup compared with supine (mean [+/- SEM] 6.26 [+/- 1.88] vs 1.68 [+/- 0.4] nmol/l; p < 0.05), and fell significantly (to 2.46 [+/- 0.65] nmol/l; p < 0.05) when returned to supine; sweating, symptom score and blood pressure followed a similar pattern. After 40 min of hypoglycaemia a similar effect of standing was seen on sweating, adrenaline and blood pressure but symptoms did not increase. Five patients underwent two further periods of hypoglycaemia, remaining supine or standing throughout. Face skin blood flow (p < 0.05) and temperature (p = 0.05) decreased when standing was maintained compared with lying. In conclusion, standing increases awareness of early hypoglycaemia and modifies many of the physiological changes. This increase in awareness is lost if hypoglycaemia is prolonged.

Investigating the capillary circulation of the foot with 99mTc-macroaggregated albumin: a prospective study in patients with diabetes and foot ulceration

Macroaggregated albumin has been used to assess capillary circulation for over 20 years. The aim of the present study was to use 99mTc-macroaggregated albumin (99mTc-MAA) perfusion scanning to assess capillary circulation in feet with ischaemic ulcers in patients with diabetes, and relate the appearances to outcome. Twenty-three patients with diabetes presented with a total of 41 neuroischaemic foot ulcers. Perfusion scanning was performed by direct femoral artery injection of approximately 400,000 particles of 99mTc-MAA and imaging with a gamma camera. Patients were followed prospectively for 3 months. Scans were graded independently by a radiologist who was unaware of the site of the ulcers. Significant associations were detected between a radiologist's assessment of increased tissue perfusion and complete healing after 3 months (p = 0.047) and poor tissue perfusion on the image and failure to heal (p = 0.0005). This technique may be useful in deciding whether to persist with conservative treatment in patients with diabetes and foot ulceration.

Subcutaneous versus intravenous administration of heparin in the treatment of deep vein thrombosis; which do patients prefer? A randomized cross-over study

Patient preference for intravenous or subcutaneous heparin in the treatment of deep venous thrombosis was assessed in a randomized cross-over study. Twenty patients with venographically proven deep venous thrombosis were randomized to receive subcutaneous or intravenous heparin for 3 days followed by 3 days of the other treatment. Discomfort at the injection site, assessed by visual analogue scale, was significantly less for the subcutaneous than the intravenous administration route (P < 0.001), mobility was thought to be better when receiving subcutaneous heparin (P < 0.005) and patients' overall preference was for subcutaneous treatment (P < 0.001).