Diagnostic delay in patients with FKRP-related muscular dystrophy

Diagnostic journey for people with FKRP mutations participating in a dystroglycanopathy natural history study (n = 68; NCT00313677) was analyzed. Earliest symptoms and age at muscular dystrophy diagnosis were abstracted from subject-reported medical history and record review. Initial signs/symptoms were classified as chronic motor dysfunction (e.g., delayed motor milestones, weakness, falling; n = 40, 59%), elevated transaminases (n = 7, 10%), or acute/intermittent symptoms (myoglobinuria, myalgia, febrile illness-associated acute weakness; n = 21, 31%). Median time from sign/symptom onset to diagnosis was 6.5 years and differed by symptom group: 7.5 years for motor group, 9 years for acute/intermittent group, and 4 years for elevated transaminases group. The sign/symptom category that most commonly resulted in a diagnosis was chronic motor dysfunction (n = 45). Of those without clear weakness as first symptom (n = 55), 36.4% were not diagnosed with MD until weakness became apparent. Median time to diagnosis was shortest for those with febrile illness-associated acute weakness (0.25 years). Median time from first sign/symptom to MD diagnosis has decreased incrementally from 18.8 years for those with onset in the 1970s to < 10 years for symptom onset occurring after 2000. Awareness of disease presentation variability will aid in earlier diagnosis, which is increasingly important with treatments in development.

Role of Thrombocytosis in Diagnosis of Giant Cell Arteritis and Differentiation of arteritic from Non-Arteritic Anterior Ischemic Optic Neuropathy

Purpose

To investigate the role of thrombocytosis in the diagnosis of giant cell arteritis (GCA), and differentiation of arteritic (A-AION) from non-arteritic (NA-AION) anterior ischemic optic neuropathy; and comparison of the sensitivity and specificity of platelet count to that of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and some other hematologic variables in the diagnosis of GCA.

METHODS

This retrospective study is based on 121 temporal artery biopsy confirmed GCA patients and 287 patients with NA-AION seen in our clinic. For inclusion in this study, all GCA patients, at their initial visit, prior to the initiation of corticosteroid therapy, must have had ESR (Westergren), platelet count and complete blood count, and temporal artery biopsy. From 1985 onwards CRP estimation was done. For inclusion in this study, all NA-AION patients at the initial visit must have undergone evaluation similar to that described above for GCA, except for temporal artery biopsy. Wilcoxon rank-sum test and the two-sample t-test were used to compare hematologic variables between GCA patients with and without visual loss, between those with and without systemic symptoms, and also between GCA and NA-AION patients. Pearson correlation coefficient was computed to measure the association of platelet counts and the other hematologic variables with ESR. Receiver operating characteristic (ROC) curves were constructed for ESR, CRP, platelet count, combinations of ESR and platelet count, and CRP and platelet count, hemoglobin, hematocrit, and white blood cell (WBC) count and the area under the curve (AUC) were compared.

Results

Comparison of ESR, CRP, and hematologic variables of GCA patients and of A-AION with the NA-AION group, showed significantly (p <0.0001) higher median levels of ESR, CRP, platelet count, and WBC count and lower levels of hemoglobin and hematocrit in the GCA patients and A-AION than in NA-AION. Comparing AUC of the ROC curve between ESR and platelet count, ESR was a better predictor of GCA compared to platelet count (AUC of 0.946 vs. 0.834). There was a slight improvement in prediction of GCA using the combination of ESR and platelet count (AUC=0.953). The other hematologic variables had an AUC that was smaller than platelet count (0.854 for hemoglobin; 0.841 for hematocrit), with WBC being the least predictive of GCA (AUC=0.666). The AUC of the ROC curve for CRP was 0.978. There was no improvement in prediction of GCA using platelet count in combination with CRP (AUC=0.976).

CONCLUSIONS

Patients with GCA had significantly (p <0.0001) higher values of platelet count, ESR, CRP and WBC but lower values for hemoglobin and hematocrit compared to the NA-AION group. Predictive ability of an elevated platelet count did not surpass elevated ESR or CRP as a diagnostic marker for GCA. Thrombocytosis may complement ESR. Hemoglobin, hematocrit and WBC were much less predictive of GCA. Elevated CRP had a greater predictive ability for GCA compared to ESR or the other hematologic parameters; thrombocytosis in combination with CRP did not yield an improvement in prediction of GCA.

Altered ADAR 2 equilibrium and 5HT(2C) R editing in the prefrontal cortex of ADAR 2 transgenic mice

Modulation of serotonin signaling by RNA editing of the serotonin 2C receptor (5HT(2C) R) may be relevant to affective disorder as serotonin functions regulate mood and behavior. Previously, we observed enhanced endogenous behavioral despair in ADAR2 transgenic mice. As the transcript of the 5HT(2C) R is a substrate of ADAR2, we hypothesized that perturbed ADAR2 equilibrium in the prefrontal cortex of ADAR2 transgenic mice alters the normal distribution of edited amino acid isoforms of the 5HT(2C) R and modifies the receptor function in downstream basal extracellular signal-regulated kinase (ERK) signaling. We examined groups of naive control and ADAR2 transgenic mice and found significantly increased ADAR2 expression, increased RNA editing at A, C, D and E sites and significantly altered normal distribution of edited amino acid isoforms of the 5HT(2C) R with increased proportions of valine asparagine valine, valine serine valine, valine asparagine isoleucine, isoleucine asparagine valine and decreased isoleucine asparagine isoleucine amino acid isoforms of the 5HT(2C) R in ADAR2 transgenic mice. Localized serotonin levels (5-HT) were unchanged and perturbed ADAR2 equilibrium coincides with dysregulated edited amino acid isoforms of the 5HT(2C) R and reduced basal ERK signaling. These results altogether suggest that altered 5HT(2C) R function could be contributing to enhanced depression-like behavior of ADAR2 transgenic mice and further implicate ADAR2 as a contributing factor in cases of affective disorder.

Caffeine restores feeding response to 2-deoxy-D-glucose in 6-hydroxydopamine-treated rats

A large portion of the central catecholaminergic nerve terminals of the rat are destroyed by administering 6-hydroxydopamine (6-HDA) via the cerebrospinal fluid. Animals lesioned in this way often appear normal, yet show many subtle behavioural abnormalities. We have been examining one example of this phenomenon, the failure of 6-HDA-lesioned rats to increase food intake when given a systemic injection of 2-deoxy-D-glucose (2-DG) (refs 5, 6). This glucose analogue seems to elicit feeding in intact rats due to its inhibition of glycolysis in cerebral chemoreceptor cells. We have proposed that lesioned animals do not eat because of an insufficient central catecholaminergic response to the severe decrease in glucose utilisation induced by 2-DG (ref. 10). If so, then pretreatments which serve to augment this neurochemical response might be expected to reinstate behavioural function. Consistent with this hypothesis, very large increases in telencephalic tyrosine hydroxylase activity in 6-HDA-lesioned animals, which occur following chronic insulin treatment, are associated with the restoration of 2-DG-induced feeding. Many of the physiological effects of catecholamines in the sympathetic nervous system seem to be mediated by an increase in the cyclic AMP concentration of the target cells. Methylxanthenes, such as caffeine and theophylline, inhibit phosphodiesterase, prevent cyclic AMP degradation, and thereby potentiate the catecholamine-stimulated rise in cyclic nucleotide. They also enhance many of the behavioural and physiological effects of catecholamines, presumably by the same mechanism. We therefore sought to determine whether the acute administration of those sympathomimetic agents, in intact and 6-HDA-lesioned rats, also would potentiate 2-DG-induced feeding, a behaviour that seems to be mediated, in part, by central catecholaminergic neurons. We report that caffeine restores the 2-DG-induced feeding response.

Ankle fractures in patients with diabetes mellitus

Diabetes mellitus is considered an indicator of poor prognosis for acute ankle fractures, but this risk may be specific to an identifiable subpopulation. We retrospectively reviewed 42 patients with both diabetes mellitus and an acute, closed, rotational ankle fracture. Patients were individually matched to controls by age, gender, fracture type, and surgical vs non-surgical treatment. Outcomes were major complications during the first six months of treatment. We contrasted secondarily 21 diabetic patients with and 21 without diabetic comorbidities. Diabetic patients and controls did not differ significantly in total complication rates. More diabetic patients required long-term bracing. Diabetic patients without comorbidities had complication rates equal to their controls. Diabetic patients with comorbidities had complications at a higher rate (ten patients; 47%) than matched controls (three patients; 14%, p = 0.034). A history of Charcot neuroarthropathy led to the highest rates of complication. An increased risk of complications in diabetic patients with closed rotational fractures of the ankle are specific to a subpopulation with identifiable related comorbidities.

Vitreous and retinal amino acid concentrations in experimental central retinal artery occlusion in the primate

PURPOSE

Vitreous and retinal amino-acid concentrations were evaluated in a primate model of central retinal artery occlusion (CRAO) to study the role of glutamate excitotoxicity in acute retinal ischaemia.

METHODS

Unilateral, acute CRAO was produced by temporary clamping of the central retinal artery for 190 min in four elderly rhesus monkeys. Fundus photography, fluorescein angiography, and electroretinogram were performed before and during CRAO, and after unclamping the artery. Vitreous samples were obtained before and after CRAO in both eyes, and analysed for 13 amino-acid concentrations using high-pressure liquid chromatography. The animals were killed 350 min after retinal reperfusion, and the retinal tissue was submitted for amino-acid analysis.

RESULTS

In all four eyes, the macula showed the 'cherry red spot'. The CRAO was confirmed by fluorescein angiography and decreased b-wave on electroretinogram. Retinal histology confirmed ischaemic changes in the inner retina. Changes in all 13 vitreous amino-acid concentrations after CRAO (including glutamate) were not significantly different between study and control eyes (P = 0.09 to 0.82). All retinal amino-acid concentrations (including glutamate) were not significantly different between two eyes (P = 0.07-0.93).

CONCLUSIONS

In the primate model of acute inner retinal ischaemia induced by transient CRAO, we were unable to detect significantly elevated concentrations of vitreous and retinal glutamate. Our primate model has the advantage of closely modelling the CRAO in humans. Further basic and clinical studies are needed to elucidate the role of glutamate excitotoxicity in retinal ischaemia.

Comparison of appropriateness ratings for cataract surgery between convened and mail-only multidisciplinary panels

BACKGROUND

In this article, the authors determine the reproducibility of appropriateness ratings for cataract surgery between a multidisciplinary physician panel that convened and a multidisciplinary physician panel that completed ratings by mail.

METHODS

Eighteen panelists, who constituted 2 distinct multidisciplinary panels, rated 2894 clinical scenarios as an appropriate, inappropriate, or uncertain indication to perform cataract surgery. Each panel's summary score for each scenario was calculated. Weighted kappa values were determined to assess the level of agreement between the ratings of the 2 panels.

RESULTS

The panels had a substantial level of agreement overall, with a weighted kappa statistic of 0.64. There was agreement on about 68% of the scenarios, and serious disagreement, in which one panel rated an indication appropriate and the other rated it inappropriate, occurred in only 1% of the ratings.

CONCLUSION

There was substantial agreement about the ratings by the 2 panels. The panel that convened rated fewer scenarios uncertain and more appropriate, suggesting the impact of group dynamics and face-to-face discussion on resolution of uncertainty.

Utility of a lung biopsy for the diagnosis of idiopathic pulmonary fibrosis

It is not known if a surgical lung biopsy is necessary in all patients for the diagnosis of idiopathic pulmonary fibrosis (IPF). We conducted a blinded, prospective study at eight referring centers. Initially, cases were evaluated by clinical history and examination, transbronchial biopsy, and high-resolution lung computed tomography scans. Pulmonologists at the referring centers then assessed their certainty of the diagnosis of IPF and provided an overall diagnosis, before surgical lung biopsy. The lung biopsies were reviewed by a pathology core and 54 of 91 patients received a pathologic diagnosis of IPF. The positive predictive value of a confident (certain) clinical diagnosis of IPF by the referring centers was 80%. The positive predictive value of a confident clinical diagnosis was higher, when the cases were reviewed by a core of pulmonologists (87%) or radiologists (96%). Lung biopsy was most important for diagnosis in those patients with an uncertain diagnosis and those thought unlikely to have IPF. These studies suggest that clinical and radiologic data that result in a confident diagnosis of IPF by an experienced pulmonologist or radiologist are sufficient to obviate the need for a lung biopsy. Lung biopsy is most helpful when clinical and radiologic data result in an uncertain diagnosis or when patients are thought not to have IPF.

Rate of visual field loss and long-term visual outcome in primary open-angle glaucoma

PURPOSE

To evaluate long-term visual field outcome in primary open-angle glaucoma.

METHODS

In this retrospective cohort study, 40 eyes of 40 patients with primary open-angle glaucoma with elevated intraocular pressure and a minimum of 8-year longitudinal series of visual fields were plotted with Goldmann perimeter. Eyes with any other ocular disease except cataract were excluded. Manual grid templates were used to quantify the visual fields. Linear regression was performed to estimate the rate of visual field decline. Pertinent clinical factors were evaluated for statistical association with the rate of decline. Long-term clinical outcome including visual acuity, rate of legal blindness, and rate of medical and surgical interventions was also measured.

RESULTS

In the 40 eyes studied, with a mean follow-up of 14 years, the visual field score decreased at the rate of -1.5% per year. Overall, 68% showed significant decrease, and the rate of decrease among these eyes was -2.1% per year. Five eyes became legally blind from glaucoma; the cumulative rate of blindness from glaucoma was 19% at 22 years. Higher intraocular pressure and greater number of antiglaucoma medications on initial presentation were associated with faster and slower deterioration of visual field (compared with the average), respectively.

CONCLUSIONS

With standard glaucoma therapy, the rate of visual field loss in primary open-angle glaucoma is slow. Lower intraocular pressure and more antiglaucoma medications are associated with slower visual field decline. Legal blindness from glaucoma is 19% over a follow-up of 22 years.

Consumption of carrageenan and other water-soluble polymers used as food additives and incidence of mammary carcinoma

This study examined the hypothesis that the increasing incidence of mammary carcinoma in the USA in the twentieth century may be related to the consumption of carrageenan and possibly other water-soluble polymers. Widely used as food additives in the Western diet, the water-soluble polymers, also known as gums, are generally regarded as inert. However, the gum carrageenan which is comprised of linked, sulfated galactose residues has potent biological activity and undergoes acid hydrolysis to poligeenan, an acknowledged carcinogen. A time-trend analysis using age-adjusted incidence data and consumption data from established sources tested the hypothesis that increased consumption of the gums may be associated with increased incidence of mammary carcinoma. Correlations were determined using Pearson and Spearman correlation coefficients, incorporating lag intervals of 10 to 35 years. This analysis demonstrated that increasing consumption of several gums correlates positively with increased incidence of breast carcinoma.

Long-term results of eyes with penetrating keratoplasty and glaucoma drainage tube implant

PURPOSE

To present long-term results of eyes with penetrating keratoplasty (PK) and glaucoma tube implant.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

We retrospectively reviewed medical records of all patients who underwent both PK and glaucoma tube implant (Baerveldt or Ahmed) at the University of Iowa between July of 1988 and December of 1997 (55 eyes).

METHODS

Success of the tube implant or PK was evaluated using Kaplan-Meier survival analysis. Association of relevant clinical factors with glaucoma or corneal graft outcome was evaluated using log-rank test or Cox proportional hazard regression analysis. The factors evaluated were glaucoma and cornea diagnoses; prior, simultaneous, and subsequent surgeries; type of tube implant; relative timing of surgeries; and postsurgical complications.

MAIN OUTCOME MEASURES

Glaucoma outcome was assessed by postoperative intraocular pressure (IOP), number of medications, and need for further glaucoma surgery. Corneal outcome was assessed by graft rejection, failure, and Snellen visual acuity. Surgical procedures before and during the study period, and their complications were evaluated.

RESULTS

The mean preoperative intraocular pressure was 29.8 mmHg with an average of 2.9 medications. At last postoperative follow-up, the mean IOP decreased to 14.3 mmHg with 0.7 medication. The tube implant successfully controlled glaucoma in 45 eyes (82%) at 3 years. More severe postsurgical complications were associated with greater glaucoma failure. Graft rejection occurred in 17 eyes, and 7 of these progressed to failure. Nonimmunologic graft failure occurred in an additional 17 eyes (31%). The remaining 31 eyes (56%) had a clear graft. The corneal grafts remained clear in 70% and 55% of eyes at 2 and 3 years, respectively. Corneal graft failure was associated with glaucoma and cornea diagnoses groups, type of tube implant, and relative timing of the two surgeries. Complications occurred in 23 eyes (42%), and 10 of these were serious.

CONCLUSIONS

A drainage tube implant can successfully control glaucoma in a majority (82%) of keratoplasty eyes at 3 years. However, the success of corneal grafts is low (55%) at 3 years. Postsurgical complications are not uncommon and are associated with poor glaucoma outcome. Other clinical factors are associated with poor graft outcome.

Physician use of and attitudes regarding the minimum data set

OBJECTIVE

To determine physician use of the Minimum Data Set (MDS), part of the Resident Assessment Instrument (RAI).

DESIGN

A population-based survey.

SETTING

The United States.

PARTICIPANTS

A total of 2223 physicians listing geriatrics as their primary specialty, 1921 of whom are internists and 302 family physicians.

MEASUREMENTS

A 34-item questionnaire asking nine physician-specific demographic questions; nursing home caseload; percent time spent reviewing MDS and care plan; how the information on the MDS was used. Physicians were also asked to describe their attitudes about the MDS.

RESULTS

Among the 472 physicians who completed the survey and cared for nursing home patients, 357 were internists and 107 were family physicians. Ninety-one percent of the physicians were board certified, 76% had certificate of added qualifications in geriatrics,65% oversaw 20 nursing home patients. Only 11% of physicians reported reviewing the entire MDS, and 21% part of the MDS for all of their patients. Nineteen percent of physicians did not review the care plan for any of their patients. Fifty-six percent of 461 comments made by physicians regarding the MDS were negative or derogatory.

CONCLUSIONS

Many practicing geriatricians are not using MDS to facilitate medical decisions. If this physician population is not using the MDS, there is a need to improve the information transfer from the MDS form to the busy clinician.

Role of nocturnal arterial hypotension in optic nerve head ischemic disorders

OBJECTIVE

To investigate the role of nocturnal arterial hypotension, intraocular pressure (IOP) and heart rate in optic nerve head (ONH) ischemic disorders, and the effects of systemic factors and topical beta-blocker eye-drops on nocturnal arterial hypotension and heart rate.

METHODS

We investigated prospectively, by 24-hour ambulatory blood pressure (BP) monitoring and diurnal curve of the IOP, 275 white patients with anterior ischemic optic neuropathy (AION - 114), normal tension glaucoma (NTG - 131) and primary open angle glaucoma (POAG - 30).

RESULTS

Hourly average BP data analyses showed a significantly greater drop in mean diastolic BP (p < 0.009) at night in NTG than AION. Cases with visual field deterioration had significantly (p = 0.05) lower minimum nighttime diastolic BP. Arterial hypertensives on oral hypotensive therapy showed a significantly lower mean nighttime systolic BP (p = 0.006) and larger mean percentage drop in systolic (p < 0.0001), diastolic (p = 0.0009) and mean (p < 0.0001) BPs. Normotensives and hypertensives without therapy had no such difference. IOP showed no significant correlation with visual field deterioration in any of these conditions. Patients using beta-blocker eyedrops, compared with those not using them, had greater percentage drop in diastolic BP (p = 0.028), lower minimum nighttime diastolic BP (p = 0.072) and lower minimum nighttime heart rate (p = 0.002).

CONCLUSIONS

Findings of our study suggest that nocturnal hypotension, by reducing the ONH blood flow below a crucial level during sleep in a vulnerable ONH, may play a role in the pathogenesis of AION and glaucomatous optic neuropathy (GON) and progression of visual loss in them. Thus, nocturnal hypotension may be the final insult in a multifactorial situation.

Phlebotomy overdraw in the neonatal intensive care nursery

OBJECTIVE

Because blood loss attributable to laboratory testing is the primary cause of anemia among preterm infants during the first weeks of life, we quantified blood lost attributable to phlebotomy overdraw, ie, excess that might be avoided. We hypothesized that phlebotomy overdraw in excess of that requested by the hospital laboratory was a common occurrence, that clinical factors associated with excessive phlebotomy loss would be identified, and that some of these factors are potentially correctable. DESIGN, OUTCOME MEASURES, AND ANALYSIS: Blood samples drawn for clinical purposes from neonates cared for in our 2 neonatal special care units were weighed, and selected clinical data were recorded. The latter included the test performed; the blood collection container used; the infant's location (ie, neonatal intensive care unit [NICU] and intermediate intensive care unit); the infant's weight at sampling; and the phlebotomist's level of experience, work shift, and clinical role. Data were analyzed by univariate and multivariate procedures. Phlebotomists included laboratory technicians stationed in the neonatal satellite laboratory, phlebotomists assigned to the hospital's central laboratory, and neonatal staff nurses. Phlebotomists were considered experienced if they had worked in the nursery setting for >1 year. Blood was sampled from a venous or arterial catheter or by capillary stick from a finger or heel. Blood collection containers were classified as tubes with marked fill-lines imprinted on the outside wall, tubes without fill-lines, and syringes. Infants were classified by weight into 3 groups: <1 kg, 1 to 2 kg, and >2 kg. The volume of blood removed was calculated by subtracting the weight of the empty collection container from that of the container filled with blood and dividing by the specific gravity of blood, ie, 1.050 g/mL. The volume of blood withdrawn for individual laboratory tests was expressed as a percentage of the volume requested by the hospital laboratory.

RESULTS

The mean (+/- standard error of the mean) volume of blood drawn for the 578 tests drawn exceeded that requested by the hospital laboratory by 19.0% +/- 1.8% per test. The clinical factors identified as being significantly associated with greater phlebotomy overdraw in the multiple regression model included: 1) collection in blood containers without fill-lines; 2) lighter weight infants; and 3) critically ill infants being cared for in the NICU. Because the overall R(2) of the multiple regression for these 3 clinical factors was only.24, the random factor of individual phlebotomist was added to the model. This model showed that there was a significant variation in blood overdraw among individual phlebotomists, and as a result, the overall R(2) increased to.52. An additional subset analysis involving 2 of the 3 groups of blood drawers (ie, hospital and neonatal laboratory phlebotomists) examining the effect of work shift, demonstrated that there was significantly greater overdraw for blood samples obtained during the evening shift, compared with the day shift when drawn using unmarked tubes for the group of heavier infants cared for in the NICU.

CONCLUSION

Significant volumes of blood loss are attributable to overdraw for laboratory testing. This occurrence likely exacerbates the anemia of prematurity and may increase the need for transfusions in some infants. Attempts should be made to correct the factors involved. Common sense suggests that blood samples drawn in tubes with fill-lines marked on the outside would more closely approximate the volumes requested than those without. Conversely, the use of unmarked tubes could lead to phlebotomy overdraw because phlebotomists may overcompensate to avoid having to redraw the sample because of an insufficient volume for analysis. We were surprised to observe that the lightest and most critically ill infants experienced the greatest blood overdraw. (ABSTRACT TRUNCATED)

Administration of recombinant human granulocyte-macrophage colony-stimulating factor to children undergoing allogeneic marrow transplantation: a prospective, randomized, double-masked, placebo-controlled trial

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered to 40 pediatric patients undergoing partially matched related, or closely matched unrelated, allogeneic marrow transplants. This trial was set up in a prospective, randomized, double-masked, placebo-controlled manner to establish if the administration of GM-CSF to such patients enhanced neutrophil recovery in this allogeneic transplant setting. The GM-CSF group had a significantly shorter time to neutrophil recovery to > 500 x 10(9) cells/L (15 days) than the placebo group (p = 0.0036). In addition, the GM-CSF group had a significantly shorter neutrophil recovery time to > 1,000 x 10(9) cells/L (18 days) than the placebo group (p = 0.0053). The primary objective of this study was met by showing that GM-CSF enhanced neutrophil recovery in this allogeneic setting. However, within the study group of patients, there was no effect of GM-CSF on the incidence or severity of graft-vs.-host disease (GvHD), one of the secondary end-points of the study. With regard to the other secondary end-points, there was no effect of GM-CSF on marrow cellularity, duration of systemic antibiotics given for real infections or as prophylaxis to prevent infections, risk of significant infections (as defined by systemic culture of virus, fungus, or bacteria), and duration or cost of hospitalization, platelet recovery, and nutritional support. With the secondary end-points, it will be necessary to study larger numbers of pediatric patients to identify differences that are small in this study group. In conclusion, GM-CSF can be safely administered to children with few, if any, significant side-effects. Additional work remains to facilitate earlier discharge of patients and decreased antibiotic usage, to offset the cost of using a neutrophil growth factor.

Laryngeal cancer cost analysis: association of case-mix and treatment characteristics with medical charges

OBJECTIVES

To examine the relationship of various pretreatment case-mix characteristics and treatment modalities with medical charges incurred during diagnosis, treatment, and 2-year follow-up for patients with laryngeal cancer.

DESIGN

Retrospective chart review and billing record analysis.

METHODS

The charts and billing records of patients diagnosed with laryngeal cancer at the University of Iowa Hospitals and Clinics (UIHC) between January 1, 1991 and December 31, 1994 were reviewed. The independent variables included various pretreatment patient-mix and tumor characteristics (age, AJCC TNM clinical stage, smoking history, ASA class, and comorbidity as defined by Kaplan-Feinstein grade) as well as type of treatment. The dependent variables included total physician, office, and university hospital-based charges incurred during the pretreatment evaluation and 0- to 3-, 3- to 12, and 12- to 24-month billing periods after the initiation of cancer-directed therapy. Total 1-year and 2-year charges were also evaluated. Univariate and multivariate analyses were used to investigate the relationships between dependent and independent variables and to develop models predictive of management charges during the individual and total billing periods.

RESULTS

Pretreatment charges showed no significant associations (P < .05) with any of the independent variables. Multiple regression analyses indicated that comorbidity, stage, and initial treatment modality were significant variables in one or more of the models predicting charges incurred during the 0- to 3-month, 3- to 12-month, total 1-year, and total 2-year billing periods. The models yielded R2 values for the total 1- and 2-year billing periods of 0.5246 and 0.5055, respectively.

CONCLUSIONS

This work supports continued study of measures that may result in earlier detection of laryngeal cancer as a potential means of reducing management charges. These results also indicate that a more accurate method of stratifying the disease severity of laryngeal cancer patients for reimbursement purposes would include measurements of the severity of the index disease as well as comorbid diseases.

Ocular and optic nerve head ischemic disorders and hearing loss

PURPOSE

To investigate in an exploratory study whether any evidence suggests that ophthalmic ischemic disorders, particularly of the optic nerve head, are associated with hearing loss.

METHODS

We investigated prospectively 583 consecutive patients in eight primary ocular diagnostic groups for associated hearing loss: nonarteritic anterior ischemic optic neuropathy (n = 81), normal-tension glaucoma (n = 36), primary open-angle glaucoma (n = 138), other types of glaucoma (n = 142), ocular arterial occlusive disorders (n = 22), retinal vein occlusion (n = 89), ocular vasculitis (n = 42), and a miscellaneous group (n = 33). The patients and their relatives were questioned in detail for any evidence of hearing loss in the patients.

RESULTS

In the logistic regression model, with presence or absence of hearing loss as the dependent variable and gender, age, and diagnosis as independent variables, gender (P = .003) and age (P<.0001) were found to be significantly associated with hearing loss. No significant association was found with any of the ophthalmic disease groups evaluated in this study. Whenever any significant association with any ophthalmic disease group was seen, this result could be explained by examination of the association between diagnosis and age, which showed a significant (P<.001) association.

CONCLUSIONS

This study showed that there is a significant (P<.001) relationship between hearing loss and aging-the older the population, the higher the incidence of hearing loss-but the study showed that there is no association between hearing loss and ocular and optic nerve head ischemic disorders. The two represent unrelated and independent disorders.

Beta-blocker eyedrops and nocturnal arterial hypotension

PURPOSE

To investigate the effects of topical beta-blocker eyedrops on nocturnal arterial hypotension and heart rate and on visual field deterioration.

METHODS

We prospectively investigated 275 white patients, 161 with glaucomatous optic neuropathy and 114 with nonarteritic anterior ischemic optic neuropathy, by 24-hour ambulatory blood pressure monitoring and diurnal curve of intraocular pressure, in addition to detailed ophthalmic evaluation. Of the patients with glaucomatous optic neuropathy, 131 had normal-tension glaucoma and 30 had primary open-angle glaucoma. Of the 275 patients, 114 were using topical beta-blocker eyedrops twice daily (76 with normal-tension glaucoma, 26 with primary open-angle glaucoma, and 12 with anterior ischemic optic neuropathy).

RESULTS

Hourly average blood pressure data analyses showed overall a drop in blood pressure as well as heart rate during sleep, and a significantly greater drop in mean diastolic blood pressure (P = .009) at night in normal-tension glaucoma than in anterior ischemic optic neuropathy. Also, patients using beta-blocker eyedrops experienced a significantly greater percentage drop in diastolic blood pressure at night (P = .028), lower minimum nighttime diastolic blood pressure (P = .072), and lower minimum nighttime heart rate (P = .002) than did those not using them. In normal-tension glaucoma, eyes receiving beta-blocker eyedrops showed visual field progression significantly (P = .0003) more often than those not receiving beta-blockers.

CONCLUSIONS

The findings of our studies, as well as those of others, suggest that any factor that increases nocturnal arterial hypotension is a potential risk factor in vulnerable individuals with glaucomatous optic neuropathy or anterior ischemic optic neuropathy. The present study suggests that the use of beta-blocker eyedrops, by aggravating nocturnal arterial hypotension and reducing the heart rate, may be a potential risk factor in susceptible individuals.

Morphologic changes in chronic high-pressure experimental glaucoma in rhesus monkeys

PURPOSE

To investigate morphologic changes in the posterior segment of the eye and optic nerve head (ONH) in rhesus monkeys with experimental glaucoma, and to evaluate the effect of age and vascular disease on the glaucomatous damage.

METHODS

This study was conducted in 36 eyes of rhesus monkeys 11 to 24 years of age. Experimental glaucoma was produced by laser photocoagulation of the anterior chamber angle in 28 eyes, and the remaining 8 eyes served as the nonglaucomatous group. Of the 28 glaucomatous eyes, 19 belonged to animals with experimental atherosclerosis and chronic arterial hypertension (A-H group); the remaining 9 had no A-H (non-AH group). Among the 8 eyes without glaucoma, 5 belonged to A-H animals and the remaining 3 to animals without A-H. All eyes underwent IOP measurements and fundus photography before laser photocoagulation and serially thereafter for 4 to 60 months (median 22.5 months). After enucleation, eyes were fixed in formalin for light microscopic studies. Morphologic abnormalities were evaluated and graded. Correlation analyses between morphologic parameters and clinical data were performed.

RESULTS

The highest IOP ranged from 44 to 80 mmHg, but during the follow-up period median IOP was mostly 28 mmHg (mean 27+/-4.8 mmHg). On histopathologic examination, the eyes showed moderate to severe atrophy of the temporal peripapillary choroid (67%), choriocapillaris (70%), and RPE (12%); axonal atrophy in the retinal nerve fiber layer (85%), prelaminar region (69%), lamina cribrosa (66%), and retrolaminar region (82%); fibrous septal thickening in the lamina cribrosa (77%) and retrolaminar region (86%); bowing backward of the lamina cribrosa (77%); overall tissue atrophy in the prelaminar region (81%); and retinal ganglion cell atrophy (74%). The data showed a positive correlation between the ONH damage and atrophic changes in the temporal peripapillary choroid, and suggested greater damage in animals with A-H than in those without A-H.

CONCLUSION

Vascular disease may influence glaucomatous damage in the ONH, as damage in the ONH was greater in animals with A-H than in those without A-H. A similar relationship also may exist between age and glaucomatous damage, but this needs to be investigated further in a larger study. It is postulated that the bowing back of the lamina cribrosa seen in optic disc cupping is produced by retrolaminar septal fibrosis and axonal loss. Although elevated IOP no doubt played an important role, the data suggest that the glaucomatous changes that were observed in this study are not simply mechanical in nature (due to the raised IOP), but may represent a multifactorial phenomenon.

Parapapillary chorioretinal atrophy in chronic high-pressure experimental glaucoma in rhesus monkeys

PURPOSE

To evaluate in rhesus monkeys parapapillary chorioretinal atrophy in chronic high-pressure glaucoma and the effects of age, atherosclerosis, and chronic arterial hypertension in a prospective, planned study.

METHODS

Seventy-six eyes from 38 monkeys were studied. First, experimental atherosclerosis and chronic arterial hypertension were produced in 24 animals. Then experimental high-pressure glaucoma was produced by laser photocoagulation of the anterior chamber angle in 38 eyes from the 38 animals. Intraocular pressure measurements and fundus photography were serially performed. The photographs were morphometrically analyzed.

RESULTS

In the glaucomatous eyes, area and frequency of beta zone of parapapillary atrophy were significantly (P < 0.0001) larger at the end of the study than at baseline. Area of beta zone was significantly (P < 0.0001) and negatively correlated with neuroretinal rim area. In an intraindividual intereye comparison, beta zone was significantly (P < 0.0001) larger in the glaucomatous than in the contralateral nonglaucomatous eyes. Increase of beta zone and loss of neuroretinal rim were independent of presence and size of beta zone at start of the study. Beta zone was significantly (P = 0.036) greater in older than in younger monkeys; however, atherosclerosis-arterial hypertension had no significant influence on frequency and size of beta zone. Area and frequency of alpha zone showed no significant change between baseline values and those at the end of study.

CONCLUSIONS

In experimental chronic high-pressure glaucoma in monkeys, beta zone of parapapillary atrophy was positively correlated with glaucomatous optic nerve damage. This confirms previous biomorphometric and histomorphometric studies on patients with glaucoma. In chronic experimental high-pressure glaucoma, neuroretinal rim loss and an increase of beta zone may be independent of preexisting parapapillary atrophy. Increase of beta zone may be independent of concomitant atherosclerosis-arterial hypertension.

Menopause and tear function: the influence of prolactin and sex hormones on human tear production

PURPOSE

The onset of dry eye is very common during menopause and may result from the loss of hormonal support. The purpose of this study was to assess the effect that changes in sex hormone and prolactin levels have on tear function in premenopausal and menopausal woman.

METHODS

Women between the ages of 30 and 60 were solicited to participate in a study concerning menopause and tear function. One-hundred and ten women were given tear function tests (osmolarity, tear volume, tear flow, Schirmer's test) and serum levels were measured for total testosterone, estradiol, prolactin, and follicle stimulating hormone.

RESULTS

For all women on hormone replacement therapy, we found a strong negative correlation between serum prolactin level and tear function. For women in menopause, total testosterone correlated positively with tear function, whereas for premenopausal women there was a negative correlation between total testosterone and tear function. Serum estradiol levels correlated positively with tear function for women 30-39 years of age, whereas for menopausal women the correlation was negative.

CONCLUSIONS

This is the first demonstration in humans that tear production is correlated with serum prolactin and sex hormone levels prior to and during the menopause.

A thyroid hormone analog stimulates angiogenesis in the post-infarcted rat heart

In view of the evidence that thyroid hormone administration has angiogenic effects on the hypertrophic myocardium, we tested the hypothesis that the capillary supply in the hypertrophic myocardium surviving infarction would be improved by administration of the thyroid hormone analog, diiodothyroproprionic acid (DITPA). We administered DITPA (MI-DITPA) or saline (MI-saline), s.c., to rats for 10 days following experimental infarction of the left ventricle (LV). Morphometric methods were used to assess capillarity and myocyte cross-sectional area in three regions of the left ventricle: (1) border (next to the scar of infarction); (2) adjacent (next to the border); and (3) remote (interventricular septum). Infarct size ranged from 20-85% of the LV free-wall, and both groups had similar mean infarct size. Capillary length density (LV) was significantly higher in the remote region of the treated group than in the MI-saline rats. LV in the border region, which experienced the most marked increase in cardiocyte cross-sectional area, was not significantly lower than in the other regions, indicating a more marked angiogenic response. In hearts with large infarcts (> or = 40%) LV in the border region was higher in the DITPA group than in the non-treated rats. In the MI-DITPA group, cardiocyte size in the border region was positively correlated with that of the other regions, which contrasts with the negative correlations noted for the MI-saline rats. These data suggest that DITPA therapy (1) may improve maximal perfusion potential of the hypertrophied myocardium surviving a myocardial infarction, and (2) is selectively effective in the border region of hearts with large infarcts.

Cost-identification analysis in oral cavity cancer management

The objectives of this study were to investigate potential relationships between pretreatment patient-mix characteristics, treatment modalities, and costs generated during the pretreatment work-up, treatment, and 1-year follow-up periods for patients with oral cavity cancer (OCC). Another objective was to identify potential areas for cost reduction and improved resource allocation in the management of OCC patients. Using a retrospective cohort of 73 patients with OCC, pretreatment patient-mix characteristics and treatment modalities were evaluated in relation to university-based charges incurred during the pretreatment evaluation, treatment, and 1-year follow-up periods. Simple regression and stepwise multiple regression analyses were used to develop predictive models for cost based on independent variables, including age, AJCC TNM clinical stage, smoking history, American Society of Anesthesiologists (ASA) class, comorbidity as defined by the Kaplan-Feinstein grade and treatment modality. The dependent measurements included all physician, office, and hospital charges incurred at the University of Iowa Hospitals and Clinics during the pretreatment evaluation, treatment, and follow-up periods, as well as the total pretreatment through 1-year follow-up management costs. Independent variables that were identified as being significantly associated with treatment costs included T classification, N classification, TNM stage, unimodality versus multimodality treatment, and the Kaplan-Feinstein comorbidity grade. Age, smoking status, and ASA class were not significantly associated with costs. The majority of the OCC management costs were incurred during the treatment period. The most substantial decreases in management costs for OCC will be realized through measures that allow identification and treatment of disease at an early stage, in which single-modality treatment may effectively be used. Resource allocation for OCC should support the investigation of measures through which the diagnosis and treatment of OCC at the earliest possible stage is facilitated. The presence of comorbid illness is a significant component in the determination of management costs for OCC and should be included in analyses of resource allocation for OCC. The singular diagnosis of OCC encompasses a wide range of patient illness severity, and diagnosis-related reimbursement schemes for OCC treatment should optimally differentiate between early and advanced stage disease.

A randomized study of mitomycin augmentation in combined phacoemulsification and trabeculectomy

PURPOSE

The purpose of the study is to determine whether the intraoperative application of subconjunctival mitomycin C (MMC), during combined phacoemulsification and trabeculectomy, is an effective means of improving filtration, defined as overall lower intraocular pressure (IOP) and less antiglaucoma medication use.

METHODS

Twenty-nine patients with a visually significant cataract and glaucoma were randomized, in a double-masked fashion, to receive intraoperative MMC (0.5 mg/ml) or placebo.

RESULTS

Follow-up ranged from 6 to 30 months (mean, 20 months). Postoperative visual acuity at 1 year was 20/40 or better in 14 of 15 eyes operated on in the placebo group and 13 of 14 eyes operated on in the MMC group. Intraocular pressure at 8 months averaged 15.2 +/- 1.5 mmHg in the placebo-treated eyes versus 12.3 +/- 1.6 mmHg in the MMC-treated eyes. At 12 months, IOPs averaged 16.2 +/- 1.5 mmHg in the placebo-treated eyes versus 12.6 +/- 1.0 mmHg in the MMC-treated eyes. On average, the MMC group had postoperative IOP levels 3.0 mmHg lower than did the placebo group (P = 0.04) throughout the study. In the placebo group, laser suture lysis was required in a greater number of patients (80% versus 43%) and to a greater extent (mean = 2.0 versus 0.7 suture lysed) (P < 0.05). At 12 months, 5 of the 15 patients in the placebo group required an average of 1.8 medications for IOP control, whereas 0 of the 14 patients in the MMC group needed IOP-lowering medications. A late endophthalmitis developed through an intact bleb in one patient in the MMC group; otherwise, complications were minimal in each group.

CONCLUSION

These results suggest that intraoperative MMC application, during combined phacoemulsification and trabeculectomy surgery, does improve early filtration as shown by overall lower IOPs and less antiglaucoma medication use.

Assessment of the tear film with tandem scanning confocal microscopy

PURPOSE

To evaluate the confocal microscopic appearance of the tear film by correlating the interference pattern created by the lipid surface with physiologic measurements of tear function and with clinic diagnosis.

METHODS

A series of 53 patients was examined with a battery of tests to evaluate the tear film and with confocal microscopy to evaluate the interference pattern created by the lipid surface of the tear film. Assessment of the tear-film appearance involved five nonparametric scales: degree of debris in the tear film, variability of the interference pattern over time, linearity of the interference pattern, number of dry spots seen, and relative thickness of the lipid layer. For 10 other subjects, the confocal appearance of the tear film and evaporation from the ocular surface was tested for before and after meibomian gland expression.

RESULTS

The confocal appearance correlated with multiple physiologic variables and clinical diagnosis. Patients with seborrheic meiboman gland dysfunction had a thicker lipid layer, greater variability, and more debris than did patients with obstructive meibomiam gland dysfunction. After meibomian gland expression, lipid thickness and linearity increased, whereas pattern variability and evaporation decreased significantly. The mean reduction in evaporation was 48%.

CONCLUSIONS

Confocal microscopy can be used to examine the tear film, and its appearance correlates significantly with physiologic variables in normal-individuals and in disease states. The confocal appearance of the lipid interference patterns and evaporation from the ocular surface are altered after lipid expression from meibomian glands.

Craniofacial growth in rabbits after rigid or semi-rigid fixation of the frontonasal suture

Treatment of craniofacial dysostosis involves complex remodeling of the cranium and facial bones. Maintenance of the newly positioned segments may be achieved by rigid fixation using plates; however, there is concern that, over time, these plates may interfere with normal growth. The purpose of this study was to test a method of "semi-rigid" fixation of an osteotomy of the frontonasal suture in juvenile rabbits by comparing standardized parameters of craniofacial growth after conventional suture plating with the experimental plating method and with growth after sham operation. Forty-five, 6-week-old, weanling rabbits were divided into three groups of 15 each (12 for cephalometry, 3 for histological examination): (group 1) control, sham operated; (group 2) rigid fixation; (group 3) semi-rigid fixation. Rabbits were maintained for 14 weeks. Craniofacial growth was assessed using three-dimensional image analysis techniques. Measurements were subjected to statistical analysis (one-way analysis of variance) to compare the three treatment groups. Pairwise comparison of means between the treatment groups was done using Bonferroni's method at the 0.05 significance level. Semi-rigid fixation permitted significantly more normal growth of the developing rabbit head than rigid fixation in total snout length, total vault length, left and right midface height, and left orbital length. Both semi-rigid and rigid fixation significantly restricted growth compared with sham operated animals in left and right posterior midface height, right orbital length, right and left nasal bone length, and left parietal width. There were no significant differences in the growth of all other parameters measured.

Tear film changes associated with normal aging

We examined a group of normal subjects to evaluate the tear film function by measuring reflex tear capacity using the Schirmer test without anesthetic, steady state tear flow using fluorophotometry, meibomian gland function based on gland drop-out, expressible lipid volume and viscosity, tear loss from evaporation, and tear osmolarity. We found the average tear flow to be 0.19 +/- 0.19 microliters/min, lower than previously measured. The average tear volume was also correspondingly less, 2.74 +/- 2.0 microliters. We found there was a decline associated with advancing age for all parameters except the decay constant and lipid volume. The highest correlations with aging were tear volume (-0.64), Schirmer test (-0.63), and tear osmolarity (0.59). Our results indicate that there is a decline in tear film function throughout life and that tear flow is considerably less than previously estimated.

Model for ocular tear film function

Blepharitis patients have a number of disturbances in their tear film associated with meibomian gland dysfunction that affect evaporation and tear osmolarity. We tested a series of 156 consecutive patients, with a presumed diagnosis of blepharitis, dry eye, or allergic disease, and a series of 72 normals. We compared their tear film characteristics using tear osmolarity, tear volume, tear production (fluorophotometric and Schirmer test), tear turnover (decay constant), tear evaporation, and meibomian gland function evaluated by gland drop-out, expressed lipid viscosity, and volume. Of the 156 patients tested, we found 37 had dry eye, 10 had only allergic disease, 73 had meibomian gland dysfunction and dry eye, and 36 had only meibomian gland dysfunction. We created a model of the relative influence some of these factors had on each other using their correlation coefficients. The highest correlations for osmolarity were Schirmer test (-0.44), lipid volume low (-0.44), lipid viscosity high (0.39), gland drop-out (0.39), and tear evaporation (0.36). With regression analysis we accounted for 47% of the total variation in osmolarity, but only 17% of the variation in tear evaporation. We also present our classification system for blepharitis and dry eye patients based on our measurable physiologic parameters.

Investigating the relationship between stroke and obstructive sleep apnea

BACKGROUND AND PURPOSE

We aimed to prospectively determine whether the incidence of obstructive sleep apnea in patients with recent stroke was significantly different from that of a sex- and age-matched control group with no major medical problems.

METHODS

We prospectively performed overnight polysomnography in 24 patients with a recent stroke (13 men and 11 women; mean age [+/- SD], 64.6 +/- 10.4 years) and 27 subjects without stroke (13 men and 14 women; mean age, 61.6 +/- 8.8 years). Patients with either ischemic or hemorrhagic stroke were entered into this study. Polysomnographic evaluations were performed within approximately 2 to 5 weeks after each patient's stroke.

RESULTS

Obstructive sleep apnea was found in 10 of 13 men with stroke (77%) and in only 3 of 13 male subjects without stroke (23%) (P=.0169). Seven of 11 women with stroke (64%) had obstructive sleep apnea, while only 2 of 14 female subjects without stroke (14%) had obstructive sleep apnea (P=.0168). For men with stroke, the mean apnea/hypopnea index (+/- SE) was 21.5 +/- 4.2 events per hour, while for male subjects without stroke it was 4.8 +/- 1.8 events per hour (P=.0014). For women with stroke the mean apnea/hypopnea index was 31.6 +/- 8.8 events per hour, while for female subjects without stroke it was 2.9 +/- 1.6 events per hour (P=.0024). The 4-year mortality for patients with stroke was 20.8%. All patients with stroke who died had obstructive sleep apnea.

CONCLUSIONS

Patients with stroke have an increased incidence of obstructive sleep apnea compared with normal sex- and age-matched control subjects. Hypoxia and hemodynamic responses to obstructive sleep apnea may have predisposed these patients to stroke.

Craniofacial growth in rabbits. Effects of midfacial surgical trauma and rigid plate fixation

OBJECTIVE

To examine the effects of soft-tissue manipulation, rigid microplate fixation, and multiple osteotomies on the growing midface in rabbits.

DESIGN

Randomized, controlled experiment.

SUBJECTS

Forty 6-week-old male New Zealand white rabbits.

INTERVENTIONS

Group 1, exposure of the left nasofrontal and midzygomatic arch regions with periosteal elevation; group 2, osteotomies at left nasofrontal suture and midzygomatic arch; group 3, rigid plate fixation of osteotomies; and group 4, rigid plate fixation alone. Animals were killed at age 20 weeks; growth was assessed by linear and spatial measurements of craniofacial regions.

RESULTS

Linear data disclosed shortening of the left nasal bone (P < .05) in groups 2 through 4. Groups 3 and 4 also had shortened left zygomatic arches and orbital diameters (P < .05). Euclidean distance matrix analysis showed significant restrictive shape alterations in groups 2 through 4 (P < .05). Significant contralateral shape alterations also were found in group 3.

CONCLUSION

Rigid plate fixation does not cause more severe growth disturbance than bony trauma. Use of rigid plate fixation after bony trauma does not seem to increase the restrictive effects of trauma on growth. Furthermore, removal of rigid plate fixation may not prevent growth disturbances and may induce further harmful trauma to the growing midface.

Avoidant personality traits distinguish social phobic and panic disorder subjects

The purpose of this study was to show that, as a group, patients with social phobia and panic disorder differ with respect to personality traits, further validating the distinction between these anxiety disorders. To show this, we compared the response of 46 subjects with social phobia with the response of 72 subjects with panic disorder with or without agoraphobia on the Personality Diagnostic Questionnaire. The subjects, who were recruited for treatment studies, completed this personality questionnaire after they had been off psychotropic medication for at least 1 week. Responses to the Personality Diagnostic Questionnaire showed that the social phobics had more severe personality pathology. These subjects had higher anxious and schizoid cluster scores and differed from panic subjects in having more avoidant personality traits. Panic subjects had more dependent traits. The results indicate that social phobic and panic disorder patients are distinguishable on the basis of personality characteristics. They also show that the generalized situational subtype of social phobia is closely associated with avoidant personality disorder and that these may be differing categorizations of a single disturbance.

Nocturnal arterial hypotension and its role in optic nerve head and ocular ischemic disorders

We measured 24-hour ambulatory blood pressure monitoring and diurnal curve of the intraocular pressure in 166 white patients with anterior ischemic optic neuropathy, normal-tension glaucoma, primary open-angle glaucoma, and other optic nerve head disorders. Hourly average blood pressure data analyses showed a significant (P < .0001) decrease in mean systolic (26%) and diastolic (33%) blood pressure measurements at night. A significantly (P = .0028) lower nighttime mean diastolic blood pressure and a significantly (P = .0044) greater mean percentage decrease in diastolic blood pressure were noted in normal-tension glaucoma than in anterior ischemic optic neuropathy. Patients with arterial hypertension taking oral hypotensive therapy showed a significant association between progressive visual field deterioration and nocturnal hypotension, particularly in anterior ischemic optic neuropathy. Intraocular pressure showed no significant correlation with visual field deterioration in any of these conditions. Our findings suggest that nocturnal hypotension, in the presence of other vascular risk factors, may reduce the optic nerve head blood flow below a critical level, and thereby may play a role in the pathogenesis of anterior ischemic optic neuropathy and glaucomatous optic neuropathy; that is, nocturnal hypotension may be the final insult in a multifactorial situation. The same mechanisms may be true of a number of other ocular ischemic disorders. This finding opens a new dimension in the understanding and management of these visually disabling diseases.

Incidence of various types of retinal vein occlusion and their recurrence and demographic characteristics

We analyzed data on 1,108 patients (1,229 eyes) with various types of retinal vein occlusion. Retinal vein occlusion was classified into six distinct clinical types: (I) nonischemic and (II) ischemic central retinal vein occlusion, (III) nonischemic and (IV) ischemic hemicentral retinal vein occlusion, and (V) major and (VI) macular branch retinal vein occlusion. Retinal vein occlusion occurred more often in men than women. The age range of patients was between 14 and 92 years, with 570 of 1,108 patients (51%) 65 years or older; however, 99 of 620 (16%), 15 of 154 (10%), and 17 of 375 (5%) of the patients with central, hemicentral, and branch retinal vein occlusion, respectively, were younger than 45 years. The cumulative probability of developing a second episode of the same or a different type of retinal vein occlusion in the same eye was 0.9% within two years and 2.5% within four years, and in the fellow eye was 7.7% and 11.9%, respectively. The cumulative probability of conversion of nonischemic to ischemic central retinal vein occlusion at six months and 18 months was 13.2% and 18.6%, respectively, in persons 65 years of age or older and 6.7% and 8.1%, respectively, in persons 45 to 64 years of age.

Initiation of cardiac hypertrophy in response to thyroxine is not limited by age

We examined the role of age in the initiation of thyroxine-induced (T4) cardiac hypertrophy. T4 (0.4 mg/kg sc) was administered to prepubescent (2 mo), young adult (6 mo), and senescent (24 mo) Fischer 344 rats for 4 days. While significant increases in left ventricular (LV) mass and RNA/LV were evident at 4 days in all T4-treated groups, the elevation in RNA/LV occurred earlier (2 days) in the senescent group. A 0.2-mg/kg dose of T4 elevated RNA values within 24 h in senescent, but not in prepubescent, rats. LV norepinephrine levels were measured to determine whether it plays a role in this model of cardiac hypertrophy. When synthesis of this catecholamine was blocked with alpha-methyl-p-tyrosine, tissue levels fell significantly in all groups, and the decrement was similar in T4-treated and control rats in the two younger groups. We conclude that: 1) the initiation of T4-induced cardiac hypertrophy is not compromised in senescent rats, 2) hearts of senescent rats respond earlier and to a lower dose of T4 than young rats, and 3) the cardiac hypertrophy that occurs in hyperthyroidism is not due to enhanced levels of available cardiac norepinephrine.

Seasonal variations in the onset of retinal vein occlusion

Seasonal variation in the development of retinal vein occlusion in 1003 consecutive patients with various types of retinal vein occlusion was studied prospectively from 1973 to 1990. No seasonal variation in the onset of any type or combination of types of retinal vein occlusion was found. This refutes previous reports of such seasonal variation, which were based on small retrospective series.

CGS 21680C, an A2 selective adenosine receptor agonist with preferential hypotensive activity

CGS 21680C (2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethyl-carboxamido adenosine) a 2-substituted analog of the riboside uronamide, 5'-N-ethylcarboxamido adenosine and the related analog CGS 21577 (2-phenethylamino-5'-N-ethylcarboxamido adenosine), have high in vitro affinity for brain striatal adenosine A2 receptors (IC50 values = 22 and 13 nM, respectively). Both compounds were considerably less active at A1 receptors with CGS 21577 and CGS 21680C having respective IC50 values of 0.76 and 3.1 microM. The former compound was thus 59-fold selective for A2 receptors whereas CGS 21680C was 140-fold selective. In contrast, the reference A2 selective ligand, CV 1808 (2-phenylaminoadenosine), showed only 8-fold selectivity as an A2 ligand, having an IC50 of 115 nM in the [3H]-5'N-ethylcarboxamide adenosine assay and an IC50 of 910 nM at the N6-[3H] cyclohexyladenosine site. Further examination of CGS 21680C showed that the compound was without effect on binding to 17 other putative neurotransmitter/neuromodulator sites indicating its selectivity as an adenosine receptor ligand. In an isolated perfused working rat heart model, CGS 21680C effectively increased coronary flow with an ED25 value of 1.8 nM. The corresponding value for CGS 21577 was 3 nM whereas that for CV 1808 was 110 nM. The EC25 for eliciting bradycardia for all three compounds was greater than 1000 nM. The effects of all three compounds could be reversed by treatment with the xanthine adenosine antagonist, xanthine amine congener.(ABSTRACT TRUNCATED AT 250 WORDS)

Enkephalinase inhibition increases plasma atrial natriuretic peptide levels, glomerular filtration rate, and urinary sodium excretion in rats with reduced renal mass

To investigate the in vivo effects of inhibition of endopeptidase 24.11, an enkephalinase enzyme shown to be involved in atrial natriuretic peptide (ANP) breakdown in vitro, we infused phosphoramidon, a specific inhibitor of endopeptidase 24.11, into rats with reduced renal mass (and chronic extracellular volume expansion) and into normal rats. Relative to baseline values in rats with remnant kidneys, phosphoramidon led to elevations of plasma ANP levels and concomitant increases in urinary sodium excretion, fractional excretion of sodium, glomerular filtration rate, filtration fraction, and urinary cyclic GMP excretion. Similar changes in renal function and urinary cyclic GMP excretion were obtained with thiorphan, another endopeptidase 24.11 inhibitor. These enhanced ANP levels and renal actions were not observed with phosphoramidon in normal rats. These results show that plasma ANP levels can be modulated in rats with reduced renal mass by inhibition of endopeptidase 24.11.

Degradation of atrial natriuretic peptide: pharmacologic effects of protease EC 24.11 inhibition

Several processes participate in the clearance of atrial natriuretic peptide (ANP) from the circulation, one of which is enzymatic degradation. Endoprotease EC 3.4.24.11 (NEP 24.11), present within the kidney in high concentration, has been shown in vitro to degrade ANP. Phosphoramidon and thiorphan, two potent NEP 24.11 inhibitors, have been shown to prevent the enzymatic degradation of ANP. The purpose of the present study was to determine if phosphoramidon or thiorphan would alter the in vivo time course of the pharmacologic effects of ANP. The magnitude and duration of the ANP-induced increase in urine output and sodium and cyclic GMP excretion were examined with and without either thiorphan or phosphoramidon. Six separate groups of anesthetized rats received either a low, medium, or high infusion rate of thiorphan or phosphoramidon. Renal responses to ANP were potentiated and prolonged during the low phosphoramidon infusion (3 Ki) and the medium thiorphan infusion (150 Ki). At high inhibitor infusion rates in the anesthetized rat, ANP elicited a marked depressor response. In the conscious spontaneously hypertensive rat (SHR), a 15-min intravenous (i.v.) infusion of ANP (1 microgram/kg/min) lowered mean arterial pressure (MAP 23 +/- 6 mm Hg), with an approximately 35-min duration of action. A simultaneous i.v. infusion of phosphoramidon (high dose) produced both a potentiation (33 +/- 3 mm Hg) and a prolongation (greater than 65 min to return to baseline) of the depressor response. These data lend support to the hypothesis that enzymatic breakdown of ANP may play an important role in regulating the actions of atrial natriuretic peptide.

Thromboxane synthase inhibition enhances action of converting enzyme inhibitors

Mean arterial blood pressure was measured over a 24-hour period from the femoral artery of conscious, unrestrained spontaneously hypertensive rats. Oral administration of the angiotensin converting enzyme inhibitor CGS 16617 significantly lowered mean arterial pressure. In contrast, both the thromboxane synthase inhibitor CGS 12970 and the thromboxane receptor antagonist BM 13505 lacked an antihypertensive action in the spontaneously hypertensive rat. When administered concurrently, the thromboxane synthase inhibitor CGS 12970 potentiated the antihypertensive action of the angiotensin converting enzyme inhibitor CGS 16617. This effect was not observed with the thromboxane receptor antagonist BM 13505. In addition to CGS 16617, CGS 12970 also potentiated the hypotensive effect of two structurally dissimilar angiotensin converting enzyme inhibitors, benazapril HCL and captopril. Indomethacin blocked the thromboxane synthase inhibition-induced potentiation of the antihypertensive action of angiotensin converting enzyme inhibitors. The thromboxane synthase inhibitor CGS 12970 had no effect on the hypotension induced by hydralazine, indicating that the hypotension is not a nonspecific action related to the fall in blood pressure. These results may suggest that converting enzyme inhibition augments the levels and actions of a hormone that stimulates prostaglandin formation. It is well established that thromboxane synthase inhibitors eliminate the formation of the vasoconstrictor thromboxane A2 and allow reorientation of eicosanoid production toward the formation of vasodilating prostaglandins, which could enhance the antihypertensive action of angiotensin converting enzyme inhibitors.

Correlation between binding affinities for brain A1 and A2 receptors of adenosine agonists and antagonists and their effects on heart rate and coronary vascular tone

The activities of a series of A1 and A2 adenosine receptor agonists and antagonists were determined using radioligand binding techniques in rat brain tissues. The potencies of these agonists on heart rate and coronary vascular tone were also assessed in the perfused working rat heart preparation. The order of potency of these agonists in producing negative chronotropic effects was similar to the rank order for their A1 receptor binding activities [6-N-cyclohexyladenosine (CHA) = 6-N-(R-phenylisopropyl)-adenosine greater than 5'-N-ethylcarboxamideadenosine (NECA) = 2-chloroadenosine greater than 2-phenylaminoadenosine] with a correlation coefficient of 0.97. Their order of potency in reducing coronary vascular tone followed the same rank order as their A2 receptor binding activities with a correlation coefficient of 0.97 (NECA greater than 2-chloroadenosine = 6-N-(R-phenylisopropyl)-adenosine = 2-phenylaminoadenosine greater than CHA). In addition, the antagonists 8-[4-[[[[(2-aminoethyl)amino]carbonyl]methyl]ox]phenyl-1,3- dipropylxanthine (XAC), 1,3-dipropyl-8-(2-amino-4-chlorophenyl) xanthine (PACPX) and 8-phenyltheophylline (8-PT) blocked the negative chronotropic effect of CHA and the vasodilatory effect of NECA in a concentration-dependent manner. The same order of potency of the antagonists was noted in blocking CHA-induced bradycardia and A1 receptor binding activities (XAC = PACPX greater than 8-PT). A similar correlation was observed for their effects in blocking NECA-induced vasodilation and A2 receptor binding activity (XAC greater than PACPX greater than 8-PT).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of two nonsulfhydryl angiotensin-converting enzyme inhibitors, CGS 14831 and CGS 16617, on myocardial damage and left-ventricular hypertrophy following coronary artery occlusion in the rat

The present study was designed to examine the effects of two new angiotensin-converting enzyme (ACE) inhibitors, CGS 14831 and CGS 16617 (3 mg/kg i. v. 1 min prior to occlusion and 4 and 24 h after occlusion), on myocardial ischemic (MI) damage and left-ventricular hypertrophy in rats. Administration of CGS 14831 or CGS 16617 inhibited angio-tensin-I-induced pressor responses by 40-100% for 4 h after each dose. Myocardial creatine phosphokinase (CK) levels were 10.6 +/- 0.6 U/mg protein in sham-MI animals, and following coronary artery occlusion for 48 h were decreased to 4.1 +/- 0.2 U/mg protein in MI + vehicle animals (p less than 0.01). CGS 14831 and CGS 16617 attenuated the decrease in CK content and resulted in 47 and 40% sparing, respectively, of the left-ventricular free wall. Neither agent attenuated the left-ventricular hypertrophy which developed following coronary artery occlusion. These data indicate that the nonsulfhydryl ACE inhibitors CGS 14831 and CGS 16617 have a significant cardioprotective effect in rats surviving 48 h, and suggest a potential therapeutic usefulness of these agents for the treatment of ischemia-induced heart failure.

Evidence for A1 and A2 adenosine receptors in guinea pig trachea

The adenosine analogs [5'-N-ethylcarboxamideadenosine (NECA), 2-Chloro-adenosine (2-ClA), R-phenylisopropyladenosine (R-PIA), N6-cyclohexyl adenosine (CHA), and N6-cyclopentyladenosine (CPA)] produced both relaxation and contraction responses in isolated guinea-pig trachea. A concentration-related relaxation response was observed in trachea which were precontracted with either histamine or KC1. This response followed an order of analog potency that was indicative of the A2 receptor subtype (NECA greater than 2-ClA greater than R-PIA greater than CPA greater than CHA). Theophylline, an adenosine-receptor antagonist, blocked this relaxation response. In addition, a concentration-related contractile response was produced with adenosine analogs in those trachea that were not previously contracted. In contrast, the contractile response followed an analog potency indicative of the A1 receptor subtype (R-PIA greater than 2-ClA = CPA = CHA). This contractile response was not mediated by cholinergic, adrenergic or histaminergic receptors. 2-ClA induced a biphasic response, while NECA only relaxed these tissue under basal tone. Unlike the relaxation response, these contractile responses were not attenuated by theophylline, but were blocked by 1,3 dipropyl-8-(2 amino-4-chlorophenyl)xanthine (PACPX). These findings confirm the existence of two subpopulations of adenosine receptors in guinea pig trachealis muscle.

Pharmacological characterization of CGS 15943A: a novel nonxanthine adenosine antagonist

CGS 15943A is a potent adenosine receptor antagonist with a novel nonxanthine heterocyclic ring structure. In vitro, CGS 15943A competitively inhibited the 2-chloroadenosine-induced A2 receptor-mediated relaxation of dog coronary artery strips contracted with KCl (25 mM). Similarly, CGS 15943A blocked 2-chloroadenosine- and N-ethylcarboxamideadenosine-induced A2 receptor-mediated relaxation of histamine-contracted guinea pig tracheal strips. Schild analysis of these results yielded pA2 values of 10.8 and 10.1 for the coronary arteries and the tracheal smooth muscle strips, respectively. In comparison, 8-phenyltheophylline blocked 2-chloroadenosine-induced tracheal response with a pA2 value of 7.0. CGS 15943A was devoid of intrinsic activity, and did not affect either histamine- or KCl-induced contractions of the smooth muscle strips. In the electrically stimulated guinea pig left atrial preparation, CGS 15943A antagonized the A1 receptor-mediated negative inotropic effects of R-phenylisopropyladenosine with a pA2 value of 7.4. In vivo, i.v. administration of CGS 15943A blocked the vasodepressor response to 2-chloradenosine in anesthetized normotensive rats with an ID50 of 0.024 mg/kg. In addition, p.o. administration of CGS 15943A (4.0 mg/kg) to conscious rats inhibited 2-chloroadenosine-induced decreases in diastolic blood pressure; maximal effects were observed 30 min after dosing, with a T1/2 of approximately 103 min. Therefore suggesting that CGS 15943A is an orally active antagonist of adenosine receptors. These results indicate that CGS 15943A antagonized both A1 and A2 receptor-mediated responses with a greater affinity toward the A2 than the A1 receptor subtype.

Central and peripheral inhibition of angiotensin converting enzyme (ACE) in the SHR: correlation with the antihypertensive activity of ACE inhibitors

A series of five structurally distinct ACE inhibitors were evaluated for their ability to inhibit tissue ACE activity in the SHR after oral administration. In the first series of experiments, the ACE inhibitors captopril, enalapril, pentopril, CGS 14824A and CGS 16617 were given to groups of SHR at doses that produced a 15 to 20 mm Hg reduction in blood pressure within 1 hour. Under these conditions of dose and time, only captopril significantly inhibited brain ACE activity (43%), whereas inhibition of serum ACE activity ranged from 72% to 99% with these agents. Inhibition of aortic ACE activity ranged from 54% to 87%, and lung ACE inhibition varied from 50% to 83%. In the second series of experiments, SHR were administered higher doses of each ACE inhibitor such that these compounds produced peak reductions in blood pressure (-25 mm Hg to -33 mm Hg) within a range of 2 to 6 hours. When tissue ACE activity was measured at the time corresponding to peak reduction in blood pressure, all five ACE inhibitors produced a significant inhibition of brain ACE activity ranging from 21% to 76%. Serum ACE activity was almost completely inhibited by these agents, with the exception of captopril (62% inhibition). The inhibition of aortic ACE activity ranged from 79% to 99%, while the inhibition of lung ACE activity did not increase under these conditions. These data suggest that ACE inhibitors may exert their maximal antihypertensive effects by inhibiting ACE in vascular tissues and brain.