The Alvarado Score is accurate in pregnancy: a retrospective case-control study.

BACKGROUND: Acute appendicitis is the most frequent abdominal condition that requires non-obstetric surgical intervention during pregnancy. This study aims to scan pregnant patients operated on for acute appendicitis to evaluate the efficiency of using the Alvarado Score (AS) for diagnosis. METHODS: Our study included 48 pregnant patients who were pre-diagnosed with acute appendicitis and operated on at our department of general surgery from January 2010 to July 2016 and whose files were accessed. Fifty-three non-pregnant female patients of reproductive age who were operated on for appendicitis during the same period were included in the study as the control group. The patients in both groups were divided into two groups based on their AS total score being 7 and ≥ 7. RESULTS: The mean age of the 48 pregnant patients was 28 (19-42) years, while the mean age of the 53 control patients was 31 (18-45) years. Among pregnant and non-pregnant women, about a third of patients had an AS < 7 (16 of 48 versus 18 of 53). There was no significant difference when the AS scores of both groups were compared (p = 0.947). Using pathology results as reference test, the sensitivity and specificity of the AS in pregnant women was 79 and 80%. CONCLUSIONS: As a result, when the data collected by our study are evaluated, we see that pregnancy does not have a negative effect on the efficacy of AS. Therefore, the AS system can be an easy, non-invasive auxiliary diagnostic tool with high diagnosis accuracy rates that can be used in pregnant patients suspected of having acute appendicitis.

The effects of lycopene on methotrexate-induced liver injury in rats.

BACKGROUND: The aim of this study was to investigate the effects of lycopene (Lyc) on methotrexate (Mtx) induced liver toxicity in rats. METHODS: Twenty-eight male Sprague-Dawley rats were divided into four equal groups: control, Lyc, Mtx and Mtx-L: Control group: Rats were given only the vehicle. Lyc group: Rats were given Lyc (10 mg/kg) with corn oil by oral gavage for ten days. Mtx group: Rats were injected intraperitoneally with a single dose of 20 mg/kg of Mtx and given corn oil by oral gavage. Mtx-L group: Rats were post-treated with Lyc (10 mg/kg) for ten days after a single dose of Mtx (20 mg/kg). RESULTS: Mtx administration increased histopathological damage, TNF-α, IL-1ß, TOS, TAS and OSI levels in tissues; AST, ALT levels in the blood. Sinusoidal dilatation, inflammatory cell infiltration and congestion were significantly improved in the Mtx-L aon histopathologic examination of the rats.In Mtx-L group that were treated at the Lyc, TNF-α and IL-1ß levels of liver tissue were decreased significantly compared to Mtx group whereas the decrease in OSI was not significant. Lyc treatment improved the AST and ALT values in Mtx-L group. But only AST improvement was significant. CONCLUSIONS: The results of this study revealed that Lyc might be useful in protecting the liver from injury due to Mtx in rats by reducing the increased proinflammatory cytokine levels (Tab. 4, Fig. 1, Ref. 44).

Does calcium dobesilate protect against intestinal ischemia-reperfusion injury induced in rats?

OBJECTIVE: In this study, we investigated whether the administration of calcium dobesilate (CD) affects oxidative stress markers and histopathological outcomes in a rat model of intestinal ischemia-reperfusion (IR) injury. MATERIALS AND METHODS: This study was conducted with 30 male Wistar rats. The rats were randomly assigned to three groups as follows: a sham group (n = 10), an IR group (n = 10), and an IR + CD group (n = 10). In the sham group, superior mesenteric artery (SMA) dissection alone was performed during laparotomy. In the IR group, the procedure included SMA occlusion for 60 min, followed by reperfusion for 60 min. In the IR + CD group, CD (100 mg/kg/day) was additionally given for two days before laparotomy by intragastric lavage. In all the rats, 2 ml of blood were drawn, and an ileal segment (approximately 2 cm in size) was removed to evaluate oxidative stress markers. The ileal segment removed was divided into two pieces, and one piece was reserved for histopathological evaluation. RESULTS: Compared to the other groups, both serum and tissue oxidative stress indices were lower in the IR + CD group. The decrease was due to CD increasing the total antioxidant capacity. Moreover, the histological analysis showed that CD reduced tissue injury. CONCLUSIONS: CD may exert a protective effect against intestinal IR injury by increasing antioxidant capacity.

Detection of borderline dosage of malathion intoxication in a rat's brain.

OBJECTIVE: Humans and other animals are liable to expose to low doses of malathion (MAL). However, experimental studies on its toxic threshold dose and toxic low-dose effects have not been conducted. The aims of this study were to detect the initiation of the toxic effects of sub-acute low doses (2.5, 5, and 10 mg/kg) of MAL by immunohistochemical and biochemical parameters in rat brain. MATERIALS AND METHODS: Twenty-eight rats were randomly assigned into four groups (n=7) including control and three different amounts of MAL-exposed groups (2.5, 5, and 10 mg/kg). RESULTS: On immunohistochemical examination, the number of caspase-3-positive cells in all MAL-exposed groups was significantly higher than in the control group. Consistent with this, the total antioxidant capacity, total oxidant status, and the levels of superoxide dismutase, malondialdehyde, and paraoxanase activity were significantly different in the 5 and 10 mg/kg MAL-exposed groups compared with the control group. Additionally, the total oxidant status and malondialdehyde levels were significantly higher in the 5 and 10 mg/kg MAL-exposed groups compared with those in the 2.5 mg/kg MAL-exposed group. CONCLUSIONS: Our results indicate that over 5 mg/kg MAL exposure may result in dose-dependent oxidative stress, increased caspase-3 activity, and launching to the toxic effects in rat brain.

Assesment the role of oxidative stress and efficacy of caffeic acid phenethyl ester (CAPE) on neurotoxicity induced by isoniazid and ethambutol in a rat model.

OBJECTIVE: The aim of this study were to investigate a role of oxidative stress and the therapeutic efficacy of caffeic acid phenethyl ester (CAPE) in the pathogenesis of neurotoxicity induced by isoniazid and etambutol in a rat model. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly divided into eight experimental groups: control, INH, ETM, INH+ETM, INH+CAPE, ETM+CAPE, INH+ETM+CAPE, and CAPE treatment group, with ten animals in each group. INH and ETM doses were given orally within tap water for 30 days. CAPE was administered into relevant groups intraperitoneally for 30 days. Brain tissue and sciatic nerve were removed for biochemical and histopathological investigation. RESULTS: In the INH, ETM, and INH+ETM groups, malondialdehyde (MDA) and total oxidant status (TOS) levels were significantly higher than those of the control group (p < 0.05). Also, in these groups, brain total antioxidant capacity (TAC) levels, and superoxide dismutase (SOD) and PON-1 activities were decreased compared with the control group (p < 0.05). By a CAPE supplement within INH and ETM groups, there was a significant decrease in MDA and TOS (p < 0.05). In addition to a significant increase in TAC levels, and SOD and PON-1 activities both in brain and sciatic nerve tissues (p < 0.05). CONCLUSIONS: CAPE may protect against INH- and ETM-induced neurotoxicity in rat brain and sciatic nerve.

The relationship of the mean platelet volume and C-reactive protein levels with mortality in ischemic stroke patients.

BACKGROUND AND OBJECTIVES: The relationship of the mean platelet volume (MPV) and C-reactive protein (CRP) values with mortality in patients with ischemic stroke is not clear. Besides, the correlation between CRP and MPV in patients with ischemic stroke has not been adequately studied yet. In the present study, our aim is to investigate the interrelationship of the CRP and MPV parameters together with their influence on mortality in patients with acute ischemic stroke. PATIENTS AND METHODS: Sixty-three patients with acute ischemic stroke have been enrolled in the study. The stroke patients were divided into 2 groups as those who died within the first 10 days and those who survived. The MPV and CRP in both groups have been compared. Also, the MPV obtained from the ischemic stroke patients were compared with the MPV of the healthy volunteers. RESULTS: A statistically significant difference (p = 0.027) was observed between the MPV of the stroke patients (8.6±1.95 fL) and the control group (7.93±0.82 fl). The MPV (9.24±1.98 fL) and CRP (10.8±7.0 mg/l) of those ischemic stroke patients who died were statistically significantly higher (p < 0.05) than the MPV (8.09±1.75 fl) and CRP (3.2±3.5 mg/l) of the patients who survived. There was also a positive correlation between the MPV and CRP of the ischemic stroke patients (r = 0.31, p = 0.029). CONCLUSIONS: The fact that there is a relationship between the MPV and CRP in ischemic stroke patients and that the CRP and MPV are higher in the ischemic stroke patients who died in comparison to those who survived may be an indication of the roles these markers play in the mortality of stroke patients.

Cerebral venous sinus thrombosis: an analyses of 47 patients.

OBJECTIVE: Cerebral venous sinus thrombosis (CVST) is an extremely rare disease and its early treatment is important for decreasing the morbidity and mortality. In present study, it was investigated to clinical and etiological factors, localization features, treatment, and prognosis of patients with CVST. PATIENTS AND METHODS: The study group included CVST cases who were followed up between January 2008 and June 2010. Demographical, clinical, radiological, etiological and prognostic characteristics of 47 patients with CVST were retrospectively investigated. RESULTS: Presentation complaints of the patients were as follows in order: acute and/or sub-acute headache (80.8%), impaired consciousness (25.5%), ear complaints (21.3%), paresis (19.1%) and epileptic seizures (14.9%). Chronic daily headache without any signs of neurological deficit was found in 10.6% of cases. Neurologic examinations of 40.4% of the CSVT patients were found to be normal. The most frequently found etiological factors were as follows: MTHFR gene mutation (25.5%), local infections due to chronic otitis complications (21.3%), puerperium (17%), pregnancy (12.8%), lupus anticoagulant positivity (12.8%). The sigmoid sinus was found to be involved in 35 patients (74.5%), the transverse sinus in 29 (61.7%) and superior sagittal sinus in 21 (44.7%). Impaired consciousness (p = 0.046), hemorrhagic infarct (p = 0.017), acute onset (p = 0.026), and presence of hemiparesis (p = 0.019) were found to be associated with increased mortality. CONCLUSIONS: New onset sub-acute or chronic headache may be the only neurologic complaint of CVST patients. Early diagnosis and anticoagulant treatment may decrease mortality and/or morbidity rates related with CVST in these patients.

Serum cytokine and pro-brain natriuretic peptide (BNP) levels in patients with migraine.

OBJECTIVE: Although migraine has been related with an increased risk for ischemic stroke and cardiovascular events, there is insufficient data for role of pro-brain natriuretic peptide (pro-BNP) in migraine. In present case-control study, serum levels of pro-inflammatory (TNF-alpha, IL-1beta and IL-6) and anti-inflammatory cytokines (IL-2, and IL-10) of migraine patients were investigated to determine the role of cytokines and pro-BNP in migraine. PATIENTS AND METHODS: Sixty-four consecutive newly diagnosed migraine patients and 34 healthy controls were enrolled. Serum TNF-alpha, IL-1beta, IL-2, IL-6, IL-10 and pro-BNP levels were measured by using a chemiluminescence assay. RESULTS: Migraine patients had significantly higher concentrations of IL-1beta and IL-6 compared with the healthy controls (for IL-1beta; 5.73 +/- 1.44 vs. 4.90 +/- 1.40 pg/mL, respectively, p = 0.006; for IL-6; 3.1 +/- 1.44 vs. 2.40 +/- 0.22 pg/mL, respectively, p = 0.007). The mean IL-10 levels were found to be significantly lower in migraine patients (3.38 +/- 2.93 pg/mL) than controls (6.76 +/- 1.48 pg/mL) (p = 0.007). There were no differences in TNF-alpha (27.2 +/- 48.1 vs. 15.4 +/- 0.7) and IL-2 (1017 +/- 661 vs. 1153 +/- 228) levels between patients with migraine and healthy controls. Migraine patients had higher concentrations of pro-BNP compared with healthy controls (27.0 +/- 28.0 versus 13.2 +/- 8.6, p = 0.006). CONCLUSIONS: Migraine patients have higher serum IL-1beta and IL-6 levels, and lower IL-10 levels than healthy subjects. These findings support that cytokines may be related to neurogenic inflammation in the pathogenesis of migraine. Also, increased pro-BNP may indicate to preclinical cardiac involvement in patients with migraine.

Sensitivity and specificity of terminal latency index and residual latency in the diagnosis of carpal tunnel syndrome.

OBJECTIVES: Traditionally, nerve conduction study (NCS) are used to diagnose carpal tunnel syndrome (CTS). However, no NCS has the sufficient sensitivity or specificity values to diagnose CTS by itself. Median terminal latency index (mTLI) and median residual latency (mRL) are parameters that calculated to identify abnormalities in distal segments of the median motor nerve. There are few studies on mTLI and mRL in the diagnosis of CTS. The objective of this study was to examine the sensitivity and specificity of mTLI and mRL together with NCS in the diagnosis of CTS. PATIENTS AND METHODS AND RESULTS: The diagnostic sensitivity of mTLI and mRL were calculated and compared with the conventional NCS. Sensitivity values of electrophysiological findings were as follows: median distal sensory latency (mDSL) 91.5%, fourth finger median-ulnar sensory (M4-U4) latency difference 91.5%, mTLI 90.1%, median sensory nerve conduction velocity (mSNCV) 87.4%, and median motor distal latency (mMDL) 68.6%. Specificity values of electrophysiological findings in those with carpal tunnel syndrome were mSNCV 98.6%, mMNCV (median motor nerve conduction velocity) 98.6%, median motor wrist muscle action potential amplitude 98.6%, median sensory nerve action potential amplitude 97.4%, mSDL 97.3% and M4-U4 (fourth finger median-ulnar sensory peak latency difference) latency difference 97.3%. In all CTS patients with long mMDL values, mTLI was found to be lower, however in 22 CTS patients (22.6%) with normal mMDL, mTLI was also found to be lower. Compared with mMDL, the sensitivity of mTLI in the diagnosis of CTS was found to be higher but its specificity was lower. No differences were found in the sensitivity and specificity of mRL and mMDL. The electrophysiological findings with the highest sensitivity and specificity in diagnosing CTS among conventional NCS were mSDL, M4-U4 peak latency difference and mSNCV. CONCLUSIONS: It was concluded that mTLI and mSDL can complete each other in the detection of abnormalities of sensory and motor fibres in the diagnosis of CTS.

Atrophy of the lateral geniculate nucleus in human glaucoma detected by magnetic resonance imaging.

AIM: To determine in vivo whether the lateral geniculate nucleus (LGN) undergoes atrophy in patients with glaucoma and vision loss compared with normal subjects. METHODS: Following institutional St Michael's Hospital Research Ethics Board approval, a prospective and masked neuroimaging study was conducted on glaucoma patients with visual-field defects affecting both eyes (n = 10) and age-matched controls (n = 8). Following informed consent, all subjects underwent 1.5-Tesla MRI. Coronal proton density magnetic resonance images of both LGNs were obtained, and LGN height measurements were measured by consensus by three neuroradiologists masked to the diagnosis. Glaucoma and control groups were compared using the t test. RESULTS: Both LGNs were identified and visualised by 1.5-Tesla MRI for every subject. Compared with controls, the mean LGN heights in glaucoma were decreased in right (4.09 (0.89) mm vs 4.74 (0.54) mm, p>0.05) and left LGNs (3.98 (0.57) mm vs 4.83 (0.95) mm; p = 0.033). The combined right and left LGN height in glaucoma was significantly decreased compared with controls (8.07 (1.06) mm vs 9.56 (0.86) mm; p = 0.005). CONCLUSION: In vivo MRI evidence of LGN degeneration in human glaucoma is consistent with ex vivo primate and human neuropathological studies. LGN atrophy may be a relevant biomarker of visual system injury and/or progression in some glaucoma patients.

Depth perception deficits in glaucoma suspects.

AIM: To investigate depth perception in glaucoma suspects compared to glaucoma patients and controls. METHODS: Glaucoma suspects (n = 16), patients (n = 18), and normal age matched controls (n = 19) aged 40-65 years were prospectively evaluated for depth perception deficits using the Frisby test. Stereoacuity was measured by stereothreshold in seconds of arc for each group. RESULTS: Glaucoma suspects showed significantly increased mean stereothreshold compared to age matched normals (144.1 (SE 35.2) v 26.6 (3.7) seconds of arc; p = 0.0004). The mean stereothreshold in glaucoma patients was also increased compared to age matched normals 148.1 (33.8) v 26.6 (3.7) seconds of arc; p = 0.0004). CONCLUSIONS: Glaucoma suspects show depth perception deficits. The impaired stereovision in glaucoma suspects suggests that binocular interactions can be disrupted in the presence of normal visual fields by standard achromatic automated perimetry.

Comparison of topical glyceryl trinitrate ointment and oral nifedipine in the treatment of chronic anal fissure.

This study was designed to compare the effect of topical glyceryl trinitrate (GTN) and oral nifedipine treatments on maximal anal resting pressure (MARP) and subsequently to assess their effectiveness in healing of chronic anal fissure (CAF). Patients were allocated randomly to receive either oral nifedipine retard (10 patients) 20 mg twice daily or instructed to apply glyceryl trinitrate (0.2 percent) ointment (10 patients) into the lower half of the anal canal twice daily. They were reviewed and assessed at the first visit and every fortnight for measurement of MARP, pain scores, blood pressure, pulse rate, healing of the fissure and adverse effects. Treatment were continued until healing had occurred or for up to 8 weeks. MARP values before and after application of the GTN ointment was 113.2 cm H2O and 72.5 cm H2O respectively (P < 0.001). Nifedipine caused a reduction in mean MARP from 105.2 to 74.0 cm H2O (P < 0.001). Linear analogue pain scores were significantly reduced after 2 weeks treatment with GTN and nifedipine (P < 0.001) and continued throughout the treatment period. At the end of the study; 7 of the 10 patients in the GTN group were deemed to be healed (5) or improved (2), compared with 6 of the 10 patients in the nifedipine group (5 healed, 1 improved). Headaches occurred in 3 patients in the GTN group, compared with one patient in the nifedipine group. There was no significant difference between GTN and nifedipine in terms of reduction in MARP and pain score, healing of the fissure and incidence of early recurrence and side effects of treatments. We conclude that GTN ointment and oral nifedipine are equally effective in the treatment of chronic anal fissure.

Human glaucoma and neural degeneration in intracranial optic nerve, lateral geniculate nucleus, and visual cortex.

The pathology of glaucoma has been extensively studied at the level of the retina and optic nerve head. Here the first clinicopathological case of human glaucoma is reported demonstrating degenerative changes in the brain involving the intracranial optic nerve, lateral geniculate nucleus, and visual cortex. Pathological evidence of neural degeneration in this patient is correlated with clinical, optic nerve head, visual field, and neuroradiology findings. Neuropathology in the glaucoma brain is compared to age matched controls. In the presence of advanced human glaucoma with 50% visual field loss, neural damage is evident in multiple vision stations within the brain.

Surgical treatment of the sigmoid volvulus.

Sigmoid volvulus is not an uncommon cause of intestinal obstruction. The purpose of this study is to evaluate the clinical features and surgical treatment methods in patients with sigmoid volvulus. Thirty-two patients operated on between January 1991 and October 2002 were reviewed retrospectively. The demographic data of the patients, clinical features, preoperative radiological and operative findings, type of surgical procedure performed, postoperative complications, mortality and duration of hospital stay (DHS) after surgery were reviewed. There were 21 male (66%), 11 female patients (34%) and their age ranged from 61 to 87 years with a median of 73.5 +/- 8.38 years. Most frequent clinical features were abdominal pain, distension and constipation. The correct preoperative diagnosis was made in 44% (14/32) of cases. Surgical treatment consisted of sigmoidectomy with primary anastomosis (R&A) (n = 9, 28%), sigmoidectomy with colostomy (R&C) (n = 16, 50%), and detorsion with sigmoidopexy (D&P) (n = 7, 22%). Concomittant diseases were more frequent in R&C group (n = 14, 87%) and this was statistically significant as compared to R&A (n = 4, 44%) (P = 0.03). Postoperative complication rate in R&C group was more frequent and DHS longer but the difference between treatment groups was not significant statistically. Two recurrences were observed in D&P group. Sigmoidectomy should be the basic principle in management of sigmoid volvulus and primary anastomosis can be performed safely in selected patients without increasing morbidity and DHS.

The identification of a dismembered human body: a multidisciplinary approach.

A criminal case was directed to a multidisciplinary forensic team for identification, concerning a victim whose head, having two gunshot wounds, had been separated by a sharp instrument and was recovered 6 months later. The purpose of this research was to determine the sex and age of the victim for human identification. Primarily, macroscopic examination of the skull, tooth, and DNA analysis was conducted for sex determination. A rough assessment of age was made from the skull based on anthropological findings, however a more definitive result of age estimation was determined utilizing dental morphology. The dental data showed an age range of 32-37 from the mineral examination and the formulation of microscopic measurements. The results obtained from the skull and dental analysis matched with the physical characteristics of the victim's body, the known personal data of this person, and with the superposition of the photos gathered by a formal request. Besides, the result of DNA profiling of the victim showed male gender and direct relationship with the victim's presumed wife and daughter. Generally, research on human identification consists of sex and age determination. The sex characteristics can be precisely proved from DNA tests. However, age can be estimated by skeletal, and dental analysis. In this case the performed sex and age analysis lead the research to the selective matching of the missing person's identity.

Brain changes in glaucoma.

There is evidence that glaucomatous damage extends from retinal ganglion cells to vision centers in the brain. In the lateral geniculate nucleus (LGN), the major relay center between the eye and the visual cortex, neurons should undergo degenerative and/or neurochemical changes in magno-, parvo-, and koniocellular pathways conveying motion, red-green, and blue-yellow information, respectively. Furthermore, in both the LGN and visual cortex in glaucoma, changes in metabolic activity are observed. The study of brain changes in glaucoma may provide new insights into the pathobiology of glaucomatous damage and disease progression, and may stimulate new detection and therapeutic strategies to prevent blindness.

Attenuation of the electrophysiological function of the corpus callosum after fluid percussion injury in the rat.

This study describes a new method used to evaluate axonal physiological dysfunction following fluid percussion induced traumatic brain injury (TBI) that may facilitate the study of the mechanisms and novel therapeutic strategies of posttraumatic diffuse axonal injury (DAI). Stimulated compound action potentials (CAP) were recorded extracellularly in the corpus callosum of superfused brain slices at 3 h, and 1, 3, and 7 days following central fluid percussion injury and demonstrated a temporal pattern of functional deterioration. The maximal CAP amplitude (CAPA) covaried with the intensity of impact 1 day following sham, mild (1.0-1.2 atm), and moderate (1.8-2.0 atm) injury (p < 0.05; 1.11 +/- 0.10, 0.82 +/- 0.11, and 0.49 +/- 0.08 mV, respectively). The CAPA in sham animals were approximately 1.1 mV and did not vary with survival interval (3 h, and 1, 3, and 7 days); however, they were significantly decreased at each time point following moderate injury (p < 0.05; 0.51 +/- 0.11, 0.49 +/- 0.08, 0.46 +/- 0.10, and 0.75 +/- 0.13 mV, respectively). The CAPA at 7 days in the injured group were higher than at 3 h, and 1 and 3 days. H&E and amyloid precursor protein (APP) light microscopic analysis confirmed previously reported trauma-induced axonal injury in the corpus callosum seen after fluid percussion injury. Increased APP expression was confirmed using Western blotting showing significant accumulation at 1 day (IOD 913.0 +/- 252.7; n = 3; p = 0.05), 3 days (IOD 753.1 +/- 159.1; n = 3; p = 0.03), and at 7 days (IOD 1093.8 = 105.0; n = 3; p = 0.001) compared to shams (IOD 217.6 +/- 20.4; n = 3). Thus, we report the characterization of white matter axonal dysfunction in the corpus callosum following TBI. This novel method was easily applied, and the results were consistent and reproducible. The electrophysiological changes were sensitive to the early effects of impact intensity, as well as to delayed changes occurring several days following injury. They also indicated a greater degree of attenuation than predicted by APP expression changes alone.

Atrophy of relay neurons in magno- and parvocellular layers in the lateral geniculate nucleus in experimental glaucoma.

PURPOSE: To determine whether in glaucoma there is atrophy of relay neurons in magnocellular and/or parvocellular lateral geniculate nucleus (LGN) layers projecting to the visual cortex and to compare the degree of neuronal atrophy in magnocellular layers with that in parvocellular layers. METHODS: Seven cynomolgus monkeys with unilateral experimentally induced glaucoma and five control monkeys were studied. The left LGN neurons in magnocellular layer 1 and parvocellular layers 4 and 6, connected to the right glaucomatous eye were examined. Immunocytochemistry with antibody to parvalbumin was used to specifically label relay neurons connecting to the visual cortex. Neuronal cell body cross-sectional area was estimated using unbiased point-counting methodology. Experimental and control groups were compared using t-tests. Analysis of covariance (ANCOVA) tests were used to compare the percentage of decrease in mean neuronal area between layers 1, 4, and 6, as a function of percentage of optic nerve fiber loss or mean IOP. There was significant correlation between percentage of optic nerve fiber loss and mean IOP. RESULTS: The mean cross-sectional area of relay neurons in magnocellular layer 1 and parvocellular layers 4 and 6 were significantly decreased in glaucoma compared with controls by 28%, 37%, and 45%, respectively. Neuronal area decreased in a linear fashion, with increasing optic nerve fiber loss or increasing mean IOP for layers 1, 4, and 6. The percentage of neuronal shrinkage in each of parvocellular layers 4 and 6, as a function of optic nerve fiber loss (P = 0.05; P = 0.001, respectively) or mean IOP (P = 0.046; P = 0.0008, respectively), was greater than that seen in magnocellular layer 1. CONCLUSIONS: Relay neurons in the LGN, which project to the visual cortex, undergo significant shrinkage in glaucoma, and neurons in parvocellular layers undergo significantly more shrinkage than neurons in magnocellular layers.