Pathophysiology and diagnosis of spontaneous intracranial hypotension

BACKGROUND

Spontaneous intracranial hypotension (SIH) has become a well-recognized syndrome. However, diagnosis of SIH is still challenging. The problem with SIH is that the precise mechanism of cerebrospinal fluid (CSF) leakage remains largely unknown and there is no definite diagnostic criterion in the imaging.

METHODS

The clinical findings of our ten cases and 301 literature reports on SIH were investigated in a retrospective analysis to clarify the pathophysiology of CSF leakage, correlate the findings of imaging studies and determine the most adequate diagnostic criteria.

RESULTS

The events precede symptoms of SIH were categorized as traumatic, secondary and strictly spontaneous (62%). The location of the spinal CSF leak remains undetectable in approximately 50% of cases reported. In 93% of patients, the CSF leakage sites were detected at the cervical or thoracic level of the spine. On recent MRI studies, 88% of patients showed spinal epidural fluid collections that most likely represent CSF leakage. MR myelography using heavily T2-weighted fast-spin-echo sequence can clearly demonstrate the site of CSF leakage. Although numerous treatment options are available, none of the treatments have been evaluated by randomized clinical trials. In 48% of papers, autologous epidural blood patch (EBP) was the treatment of choice in patients who have failed initial conservative management. Forty-nine percent of patients showed relief of symptoms after up to three repeated EBPs.

CONCLUSION

We propose new diagnostic criteria of SIH to avoid misdiagnosis.

Osteopontin as biomarker in early invasion by squamous cell carcinoma in tongue

BACKGROUND

Osteopontin (OPN) expression in squamous cell carcinoma (SCC) of the tongue has not been clearly elucidated.

METHODS

We selected 46 cases of tongue SCC and investigated the expression of OPN by immunohistochemical staining. The immunopositive reaction and score for each case were semiquantitatively evaluated.

RESULTS

Scores were significantly higher in carcinoma nests than in neighboring normal epithelium or epithelial dysplasia. The OPN was expressed clearly in the cytoplasm of carcinoma cells. In cases of early invasive carcinoma, in particular, expression of OPN showed a remarkable increase at the invasion front compared with the non-invaded regions. However, there was no significant correlation between expression of OPN in the primary tumor nest and lymphatic metastasis, recurrence, or survival rate.

CONCLUSION

This suggests that OPN is a useful biomarker of early invasion by SCC in tongue.

Indicators for blood glucose control in diabetics with end-stage chronic renal disease: GHb vs. glycated albumin (GA)

Diabetics with end-stage renal disease (ESRD) exhibit abnormal life span of erythrocytes, and thus, HbAlc is not necessarily a good indicator for blood glucose control. The present study was conducted to reaffirm this point and determine whether glycated albumin (GA) can be used instead of HbAlc. The following three groups of patients with diabetes served as subjects: 49 predialysis patients with ESRD (predialysis group), 37 patients with ESRD on dialysis (dialysis group), and 40 patients without nephropathy (non-dialysis group). The profile set mean blood glucose was calculated by measuring blood glucose levels seven times a day. The relationship of profile set mean blood glucose with HbAlc and GA levels was then investigated. Corrected HbAlc levels were calculated by applying the profile set mean blood glucose of each ESRD patient to the regression formula for the HbAlc of non-dialysis patients. The actual and corrected HbAlc levels for the predialysis patients were 5.4+/-1.1 and 7.9+/-1.1%, respectively, while those for the dialysis patients were 5.6+/-1.0 and 7.5+/-0.9%, respectively (p<0.0001). The changes in GA levels in relation to the blood glucose control in the dialysis patients matched those in non-dialysis patients. HbAlc levels for diabetics with ESRD were lower than indicated by their blood glucose control. When assessing blood glucose control based solely on HbAlc, erroneous results may be obtained. In such cases, GA may be used instead of HbAlc.

Correlation between reduction of syndecan-1 expression and clinico-pathological parameters in squamous cell carcinoma of tongue

We examined expression of syndecan-1 in squamous cell carcinoma (SCC) of tongue using immunohistochemistry. Forty-three cases of SCC arising in lateral border of tongue were investigated. From the immunohistochemical staining pattern, the cases were divided into two groups based on expression of syndecan-1 at the supra-peripheral cells of the tumor nest: Group A, completely or mainly positive; Group B, sporadically positive or negative. Most poorly differentiated SCC cases were classified into Group B (81.8%). The number of Group B cases in T1-2 was different from that in T3-4. The number of cases where syndecan-1 expression was reduced was much greater in T3-4, and represented the majority of Group B (86.7%). More than 80% of Grade 4D cases were in Group B (83.3%) based on the Yamamoto-Kohama criteria. These results indicate that reduction of syndecan-1 correlates to histological grade, tumor size and mode of invasion in tongue SCC.

Alteration of gap junction proteins (connexins) following lateral fluid percussion injury in rats

Gap junctions are intercellular channels that mediate the cytoplasmic exchange of small hydrophilic molecules and are formed by a family of integral membrane proteins called connexins (Cxs). Cx43 is expressed predominantly in astrocytes, while Cx36 is expressed in neurons. In this study, we show alteration of Cx43 and Cx36 in the hippocampus after traumatic brain injury in rats. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury of moderate severity. Brain coronal sections were used for immunohistochemistry with Cx43 and Cx36 antibodies. Cx43 immunoreactivity was increased in reactive astrocytes in the damaged hippocampus 24 hours after injury, and persisted for 72 hours. On the other hand, Cx36 immunoreactivity increased in CA3 neurons 1 hour after injury, and decreased later. These results indicate that gap junctions might participate in the pathophysiological process after traumatic brain injury.

Magnetic resonance imaging and computed tomography in the diagnoses of brain metastases of lung cancer

We evaluated the usefulness of double-dose (0.2 mmol/kg of gadoteridol) contrast-enhanced magnetic resonance imaging (C-E MRI) in detecting brain metastases of lung cancer. We prospectively enrolled 134 patients with lung cancer who had no neurologic symptoms and who underwent a staging work-up. Patients were assigned to receive both contrast-enhanced computerized tomography (C-E CT) and double-dose C-E MRI. Double-dose C-E MRI detected brain metastases in 19 patients, while C-E CT detected brain metastasis in only 12 of the 19 (P = 0.02). The 3-month survival rate for patients in double-dose C-E MRI group was found to be 2.06 times that of patients in a C-E CT group (P = 0.029), although the survival rate fell to 1.45 (P = 0.387) at 6 months. The results imply that double-dose C-E MRI changed the clinical stage of lung cancer patients. We concluded that double-dose C-E MRI improves the rate of detection of brain metastases during the initial staging of lung cancer.

MRI analysis of hydrocephalus associated with acoustic neurinoma

We investigated the hydrocephalus in 24 patients associated with acoustic neurinoma. We found the high incidence of homo-lateral ventricular dilatation to the side of the acoustic neurinoma. Utilizing magnetic resonance imaging, the diameter of the tumor parallel to the pyramidal bone, diameter of the tumor perpendicular to the pyramidal bone, grade of the 4th ventricle deviation, and the shape of the tumor (round or oval) were analyzed. Ten (42%) of the 24 patients with acoustic neurinoma were found to have hydrocephalus. Seven (70%) of the 10 patients with hydrocephalus exhibited asymmetrical lateral ventricle dilatation: in all cases the lateral ventricle in the hemisphere homolateral to the acoustic neurinoma was larger than that of the contralateral side. The hydrocephalus was not related to the grade of the 4th ventricle deviation but rather to the diameter of the tumor parallel to the pyramidal bone (p < 0.01). The diameter of the tumor parallel to the pyramidal bone was also related to the asymmetrical lateral ventricular dilatation (p < 0.05).

Focal brain edema and natriuretic peptides in patients with subarachnoid hemorrhage

Central salt wasting syndrome may be caused by pathological increases in serum natriuretic peptides after subarachnoid hemorrhage (SAH). However, it is unclear as to why the serum concentration of atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) increases in the subacute phase of SAH. The present study was designed to assess the correlation between focal brain edema and serum concentration of ANP or BNP in patients with SAH. Focal brain edema was found in 8 SAH-patients and peaked between days 4 and 7 of SAH. The mean serum ANP and BNP levels in patients with focal brain edema were significantly higher than those in patients without focal brain edema between days 4 and 14 of SAH. These results suggest that focal brain edema might correlate with increased levels of ANP and BNP in the subacute phase of SAH.

Vascular endothelial growth factor expression in pituitary adenomas

Vascular endothelial growth factor (VEGF) is known to be a mediator of angiogenesis and vascular permeability. A cystic component and hemorrhage are often found in pituitary adenomas. In the present study we assess the VEGF expression based on immunohistochemical examinations in 48 pituitary adenomas. All the adenomas showed some VEGF immunoreactivity mainly in the cytoplasm of tumor cells. Of the 48 adenoma-cases, 16 cases had a strong VEGF immunoreactivity, 26 cases had a moderate one, and 6 cases had a weak one. On the MR images, a cystic component was found in 16 cases (33.3%), and a hemorrhage was found in 18 cases (37.5%). The VEGF immunoreactivity had a significant relationship with the cystic component but neither the hemorrhage, size, recurrence, or HE classification. These findings suggest that VEGF might play a potential role in the pathogenesis of cystic formation in pituitary adenomas.

Characteristic phosphorylation of the extracellular signal-regulated kinase pathway after kainate-induced seizures in the rat hippocampus

Extracellular signal-regulated kinase (ERK) pathways play a crucial role in cell growth and long-lasting neuronal plasticity. Several studies have shown that phosphorylated-ERK (p-ERK) significantly increases after kainic acid (KA) administration. However, little or no information is available about the spatial distribution of p-ERK after KA-induced seizures. We herein show that KA-induced seizures significantly increase p-ERK in both neurons and astrocytes in rat brain using Western blots and immunohistochemistry. A strong immunoreactivity for p-ERK was induced in the dentate hilar neurons and CA3 neurons 30 mins and 6 hrs after KA injection. In addition, immunoreactivity for p-ERK was seen in astrocytes 6 hrs after KA injection. 72 hrs after KA injection, all pyramidal neurons had died. These findings suggest that the ERK pathway participates in the KA-induced neurotoxicity in the rat hippocampus.

Extracellular superoxide dismutase following cerebral ischemia in mice

We describe the changes in extracellular superoxide dismutase (EC-SOD) following cerebral ischemia in mice. Mice were subjected to transient forebrain ischemia and reperfusion. The measurements of EC-SOD using ELISA showed increased brain EC-SOD after 24 h of reperfusion. The immunohistochemical examination showed that EC-SOD immunoreactivity in cortical and striatal capillary wall was conspicuous after 3 h. EC-SOD immunoreactivity was also noted in cortical neurons after 24 h. Northern blot analysis showed an increased EC-SOD mRNA expression in the brain after 24 h. In situ hybridization study demonstrated no mRNA expression of EC-SOD following ischemia and reperfusion in the capillary wall. These findings suggest that serum EC-SOD might accumulate on brain endothelial cells, while cortical neurons produce EC-SOD themselves after cerebral ischemia with reperfusion.

A role of glial fibrillary acidic protein in hippocampal degeneration after cerebral trauma or kainate-induced seizure

Astrocytes perform a variety of functions in the adult central nervous system (CNS). Recent evidence suggests the robust upregulation of glial fibrillary acidic protein (GFAP) after CNS insult. However, little is known about the role of GFAP in the hippocampal degeneration after brain injury. We herein compared the GFAP knockout (KO) and wild type (WT) mice on the histological and behavioral outcome in response to cerebral trauma or kainic acid (KA)-induced seizure. Although all KO mice showed hippocampal CA3 neuronal degeneration. WT mice did not show any neuronal degeneration in CA3 subfield at 72 hrs after trauma. Thereafter, KO mice showed a higher susceptibility to KA-induced seizures and an increased number of pyknotic CA3 neurons 72 hrs after KA administration. These results indicate that GFAP plays a crucial role in the hippocampal neurodegeneration after CNS insult.

Mitogen-activated protein kinases phosphorylation in posttraumatic selective vulnerability in rats

Mitogenic stimulation of the Mitogen-activated protein kinase (MAPK) pathway modulates the activity of many transcriptional factors leading to biological responses. Of these, three MAPK cascades are well characterized as extracellular signal-regulated protein kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 pathways. The aim of this study was to investigate the topographic distribution and the role of activated MAPK pathways after fluid percussion injury (FPI) in rats. In the present results, FPI significantly induced ERK- and JNK-phosphorylation, but not p38-phosphorylation in the cortex and hippocampus at the injury site. The immunoreactivity for phospho-ERK was localized in the superficial neuronal layers, dentate hilar neurons, and the damaged CA3 neurons after 30 mins of FPI. Double immunostaining showed that phospho-ERK was prominent in astrocytes 6 hrs after TBI. The current results suggest that MAPK pathways are involved in signal transduction after FPI.

ICP monitoring following bilateral carotid occlusion in GFAP-null mice

To investigate the possible role of glial fibrillary acidic protein (GFAP) in cerebral ischemia, we have monitored the intracranial pressure (ICP) and local cerebral blood flow (ICBF) following bilateral carotid artery occlusion (BCAO) in GFAP-null mice and their wild type littermates. GFAP-null mice (B6, 129-GfaptmlMes) were obtained from Jackson Laboratories. The ICP and ICBF was continuously monitored during 15 minutes BCAO and reperfusion. The variation of the circle of Willis was also investigated in both GFAP-null and wild type mice. The breakdown of blood brain barrier (BBB) was assessed by immunohistochemical staining against mouse immunogloblins (IgG). A significantly more profound and immediate decrease in ICBF after BCAO was observed in GFAP-null mice (p < 0.04, ANOVA). GFAP-null mice also showed a significant increase (% change) in ICP after reperfusion (p < 0.05, ANOVA). There were no gross differences in the circle of Willis between GFAP-null and wild type mice. No abnormal IgG immuno-reactivity was observed in the forebrain of both animals. These results indicate a high susceptibility to cerebral ischemia in GFAP-null mice and suggest an important role for astrocytes and GFAP in the progress of ischemic brain damage and increased ICP after cerebral ischemia with reperfusion.

Hydrostatic brain edema: basic mechanisms and clinical aspect

The term hydrostatic brain edema results from unfavorable hydrtostatic pressure gradiernts between blood vessels and brain tissue. Arterial hypertension combined with decompressive craniectomy produces extensive brain edema in the arterial boundary zone of the decompressive area. The increased hydrostatic pressure gradient enhances tissue damage and causes the biphasic opening of the blood-brain barrier (BBB). The hydrostatic pressure alone is capable of causing the initial BBB opening and this induced edema results in derangement of cerebral microcirculation and metabolism. With morphological opening and metabolic damage of the vascular wall, the second BBB opening is elicited by the amplified hydrostatic pressure gradient, which is similar to that in vasogenic edema. In the clinical aspect, the beneficial effect of decompressive craniectomy in the treatment of uncontrollable ICP and brain edema remains controversial. External decompression may have adverse effects on severe brain edema and swelling. In this regards, control of driving force for the formation of brain edema could be the treatment of choice as an initial step. In addition, recent reports provided by MR imaging indicated new information on the pathophysiological features of the patients with acute hypertension. In the patients with hypertension due to reversible posterior leucoencephalopathy (RPL) syndrome, MR images show reversible signal abnormalities in the bilateral occipital lobes, suggesting hydrostatic brain edema.

Female gender as a risk factor for hypokalemia and QT prolongation after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) often causes hypokalemia and QT prolongation. The sex disparities among 73 patients with SAH and 96 control subjects were examined. On the first day of SAH, the mean serum potassium level was significantly lower and the mean corrected QT interval was significantly longer in the female SAH group compared with either the female control or male SAH group. These findings suggest female susceptibility to hypokalemia and QT prolongation after SAH.

Immunohistochemical expression of CA19-9 and CA125 in mucoepidermoid and adenoid cystic carcinomas of the salivary gland

This study examined the immunohistochemical expression of carbohydrate antigens CA19-9 and CA125 and their relationship to various biological parameters in 27 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ACC) arising from salivary glands. The series showed higher immunopositivity for CA125 (67% for MEC; 33% for ACC) than for CA19-9 (59% for MEC; 11% for ACC). CA19-9 epitope was mainly expressed in cystic (MEC) and cribriform/tubular (ACC) components of carcinoma tissues. Solid components in MEC occasionally showed positive staining for CA19-9. CA125 was evenly expressed in both ACC and MEC tissues regardless of their different histological components. The positive expression of CA19-9 and CA125 in the carcinoma tissues did not influence the clinical course of patients with MEC and ACC. A significant relationship was only demonstrated between the immunohistochemical expression of CA125 and the low proliferative activity (LI) evaluated by Ki-67 immunohistochemistry. However, no significant relationship was found between LI and the patients' clinical course. These results suggest that the immunostaining for CA19-9 and CA125 provide no reliable data to predict the clinical course of patients with MEC and ACC of the salivary glands.

Report of the Committee on the classification and diagnostic criteria of diabetes mellitus

In 1995, the Japan Diabetes Society (JDS) appointed the Committee for the Classification and Diagnosis of Diabetes Mellitus. The Committee presented a final report in May 1999 in Japanese. This is the English version with minor modifications for readers outside Japan.

CONCEPT OF DIABETES MELLITUS

Diabetes mellitus represents a group of diseases of heterogeneous etiology, characterized by chronic hyperglycemia and other metabolic abnormalities, which are due to deficiency of insulin effect. After a long duration of metabolic derangement, specific complications of diabetes (retinopathy, nephropathy, and neuropathy) may occur. Arteriosclerosis is also accelerated. Depending on the severity of the metabolic abnormality, diabetes may be asymptomatic, or may be associated with symptoms (thirst, polyuria, and weight loss), or may progress to ketoacidosis and coma.

CLASSIFICATION

Both etiological classification and staging of pathophysiology by the degree of deficiency of insulin effect need to be considered. The etiological classification of diabetes and related disorders of glycemia includes, (1) type 1; (2) type 2; (3) those due to specific mechanisms and diseases; and (4) gestational diabetes mellitus. Type 1 is characterized by destructive lesions of pancreatic beta cells either by an autoimmune mechanism or of unknown cause. Type 2 diabetes is characterized by combinations of decreased insulin secretion and decreased insulin sensitivity (insulin resistance). Category (3) includes two subgroups; subgroup A is diabetes in which specific mutations have been identified as a cause of genetic susceptibility, while subgroup B is diabetes associated with other pathologic conditions or diseases. The staging of glucose metabolism includes normal, borderline and diabetic stages. The diabetic stage is further classified into three substages; non-insulin requiring, insulin-requiring for glycemic control, and insulin-dependent (ID) for survival. In each individual, these stages may vary according to the deterioration or the improvement of the metabolic state, either spontaneously or by treatment.

DIAGNOSIS

The confirmation of chronic hyperglycemia is a prerequisite for the diagnosis of diabetes mellitus. The state of glycemia may be classified within three categories, diabetic type; borderline type; and normal type. Diabetic type is defined when fasting plasma glucose (FPG) is 7.0 mmol/l (126 mg/dl) or higher, and/or plasma glucose 2 h after 75 g glucose load (2hPG) is 11.1 mmol/l (200 mg/dl) or higher. A casual plasma glucose (PG) > or =11.1 mmol/l (200 mg/dl) also indicates diabetic type. Normal type is defined when FPG is below 6.1 mmol/l (110 mg/dl) and 2hPG below 7.8 mmol/l (140 mg/dl). Borderline type includes those who are neither diabetic nor normal types. These cutoff values are for venous PG measurements. The persistence of 'diabetic type' in a subject indicates that he or she has diabetes. For children, a dose of 1.75 g/kg (maximum, 75 g) is used for oral glucose tolerance test (OGTT). The procedure for clinical diagnosis is as follows. Diabetes mellitus is diagnosed when hyperglycemia meeting the criteria for 'diabetic type' is shown on two or more occasions examined on separate days. Diabetes can be diagnosed by a single PG test of 'diabetic type' if one of the following three conditions co-exists, (1) typical symptoms of diabetes mellitus; (2) HbA1c > or =6.5% by a standardized method; or (3) unequivocal diabetic retinopathy. If the above conditions ((1) or (2)) have been present in the past and well documented, the subject is diagnosed either to have diabetes or to be suspected of diabetes, even if the present level of glycemia does not reach that of 'diabetic type'. If the diagnosis of diabetes cannot be established by these procedures, re-testing of PG is recommended after an appropriate interval. The physician should assess not only the presence or absence of diabetes, but also its etiology and glycemic stage, and the presence and absence of diabetic complications or associated conditions.

EPIDEMIOLOGICAL ASPECTS AND SCREENING

In order to determine the prevalence of diabetes in a population, 'diabetic type' may be regarded as 'diabetes'. The use of 2hPG cutoff level of > or =11.1 mmol/l (200 mg/dl) is recommended. If this is difficult, the FPG cutoff level of > or =7.0 mmol/l (126 mg/dl) can be used, but is likely to lead to under-ascertainment. For screening, the most important point is not to overlook 'diabetes'. In addition to parameters of hyperglycemia, clinical information such as family history, obesity etc., should be regarded as indications for further testing.

NORMAL TYPE AND BORDERLINE

Only FPG and 2hPG are adopted as cutoff values, but in clinical situations, it is recommended to measure PG also at 30 and 60 min during 75 g OGTT. Among people with normal type, those with 1hPG higher than 10.0 mmol/l (180 mg/dl) are at higher risk to develop diabetes than those with lower 1hPG. When OGTT is performed, the borderline type corresponds to the sum of impaired fasting glycemia (IFG) plus impaired glucose tolerance (IGT) according to the new WHO report. Subjects in this category are at higher risk of developing diabetes than those with 'normal type'. Those with low insulinogenic index (the ratio of increment of plasma insulin to that of PG at 30 min during OGTT) are at particularly high risk to develop diabetes. Microvascular complications are rare but arteriosclerotic complications are fairly frequent in this category.

GESTATIONAL DIABETES MELLITUS (GDM)

The current definition of GDM is ' any glucose intolerance developed or detected during pregnancy'. We adopt the proposal of the Japan Society of Gynecology and Obstetrics for the diagnosis of GDM (1984). GDM is defined when two or more values during a 75 g OGTT are higher than the following cutoff levels; FPG > or =5.5 mmol/l (100 mg/dl), 1hPG > or =10.0 mmol/l (180 mg/dl) and 2hPG > or =8.3 mmol/l (150 mg/dl). As a screening test, subjects with casual PG > or =5.5 mmol/l (100 mg/dl) are recommended for further testing. Patients who have had documented glucose intolerance before pregnancy, and who present as 'diabetic type' should be under closer supervision than those who develop GDM during pregnancy for the first time. HbA1c: There is a large overlap in the distribution of HbA1c between groups with 'normal type' and 'borderline type' and mild 'diabetic type'. Therefore, HbA1c is not a suitable parameter to detect mild glucose intolerance. HbA1c higher than 6.5% suggests diabetes, but HbA1c below 6.5% alone should not be taken as evidence against the diagnosis of diabetes. COMPARISON WITH REPORTS OF AMERICAN DIABETES ASSOCIATION (ADA) IN 1997 AND WHO IN 1999: The present report is unique in the following points when compared with those of the ADA 'Diabetes Care 20 (1997) 1183' and WHO 'Report of a WHO Consultation (1999)'. (1) Diabetes due to specific mechanisms and diseases is divided into two subgroups; diabetes in which genetic susceptibility is clarified at the DNA level and diabetes associated with other diseases or conditions. (2) Cutoff PG levels are the same as those of ADA and WHO, but a term 'type' is added to each glycemic category, because a single coding of 'diabetic type' hyperglycemia does not define diabetes. Diabetes is diagnosed when 'diabetic type' hyperglycemia is shown on two or more occasions. (3) A single 'diabetic type' hyperglycemia is considered sufficient for the diagnosis of diabetes, if the patient has typical symptoms, HbA1c > or =6.5%, or diabetic retinopathy. (4) OGTT is recommended for those with mild hyperglycemia, because FPG criteria alone would overlook many subjects with 'diabetic type' in Japan. High 1hPG without elevation of FPG and 2hPG is also considered to be a risk factor for future diabetes. (5) Borderline type in the present report corresponds to the sum of IFG and IGT by WHO when OGTT is performed. (6) New criteria for GDM by OGTT are proposed.