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Biomedical subjects

Naomi Hizuka

Publications and source records attributed to Naomi Hizuka.

At least 19 recordsLinked to original sources
PubMed2006

Expression of type 5 somatostatin receptor in TSH-secreting pituitary adenomas: a possible marker for predicting long-term response to octreotide therapy.

In TSH-secreting pituitary adenomas (TSHoma), octreotide (OCT) therapy reduces tumor size and TSH secretion in some cases but not in others. As OCT acts through various types of somatostatin receptors (SSTRs), the different responses of TSHoma to OCT might be explained by the differences of SSTR expression. We therefore studied the expression of subtype-specific SSTR mRNA transcripts in tumor tissues by RT-PCR. Type 2 (SSTR2) mRNA transcripts were detected in all 8 tumors but those of SSTR3 and SSTR5 were demonstrated only in 5 of them. Serum TSH levels were decreased by OCT administration test in all patients but OCT therapy was effective in two patients out of three. SSTR5 mRNA was detected in two tumors from the responder, but not in one tumor that was resistant to OCT. These observations suggest that the temporal decrease of TSH by OCT may be mediated by SSTR2, and that the long term response to OCT therapy may be related with the expression of SSTR5. Therefore, the expression of SSTR5 in TSHoma may be a useful marker for predicting the outcome of the therapy, but further studies with larger numbers of patients are necessary.

Adenoma↗
PubMed2006

Clinical features of insulin-like growth factor-II producing non-islet-cell tumor hypoglycemia.

In some patients with non-islet-cell tumor hypoglycemia (NICTH), a high molecular weight form of IGF-II (big IGF-II) derived from tumors is present in the circulation and might be associated with recurrent hypoglycemia. In this study, in order to survey the clinical characteristics of patients with IGF-II producing NICTH, we analyzed the medical records of 78 patients with NICTH (M/F 44/34, age 62+/-1.8, range; 9-86 years.) whose serum contained a large amount of big IGF-II. Hepatocellular carcinoma and gastric carcinoma were the most common causes of NICTH. The diameters of the tumors were more than 10 cm in 70% of the patients. Basal immunoreactive insulin (IRI) levels were less than 3 microU/dl in 79% of the patients. Hypoglycemic attack was the onset of disease in 31 of 65 cases (48%), but the tumor was revealed prior to the occurrence of hypoglycemia in 34 cases (52%). Twenty-five of 47 (53%) patients had decreased serum potassium levels. These data suggested that hypoinsulinemic hypoglycemia associated with the presence of a large tumor supports the diagnosis of IGF-II producing NICTH. Hypokalemia was associated with hypoglycemia in some patients. The BMI (21.4+/-0.6 kg/m2) and serum total protein levels (6.6+/-0.1g/dl) were preserved at the occurrence of first hypoglycemic attack suggesting that malnutrition might not be the main cause of hypoglycemia in most patients.

Adolescent↗
PubMed2006

Hyponatremia after transsphenoidal surgery for hypothalamo-pituitary tumors.

Transient diabetes insipidus is a well-known complication after transsphenoidal surgery (TSS). On the other hand, transient hyponatremia has been reported as being a delayed complication of TSS. Transient hyponatremia has been attributed to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), but the details of hyponatremia have not been clarified. In the present study, we retrospectively reviewed 110 consecutive patients (39 males and 71 females, age 9-80 years) operated on transsphenoidally for pituitary and hypothalamic tumors. We investigated the frequency, time of onset, duration of hyponatremia after TSS, and analyzed possible factors associated with it. A postoperative sodium concentration <135 mEq/l was observed in 29 (26%) patients. Five patients were excluded from this study because their hyponatremia could be due to either overdose of desmopressin or SIADH for meningitis. Therefore, we investigated 24 (22%) patients with hyponatremia in this study. The sodium levels in the patients with hyponatremia ranged from 110 to 134, with a mean of 126.2 +/- 5.3 mEq/l. Hyponatremia was observed on average on postoperative day 9.5 +/- 2.4, the serum sodium levels normalized within 3.8 +/- 1.7 days. Hyponatremia occurred in patients with non-functioning pituitary adenoma (26%, 11/42), Rathke's cleft cyst (29%, 5/17), prolactinoma (31%, 4/13) and acromegaly (15%, 4/27). 18 patients (75%, 6/24) who developed hyponatremia had macrotumor (>10 mm), and 6 patients (25%, 6/24) had microtumor. The plasma arginine vasopressin (AVP) levels in the patients with hyponatremia ranged from 0.21 to 2.1, with a mean of 0.79 +/- 0.46 pg/ml, and the levels were inversely correlated with plasma osmolality (r = -0.80, p = 0.002). The urine to plasma osmolality ratios were >1. All the patients received appropriate hormonal replacement, including hydrocortisone. These data showed that postoperative hyponatremia after TSS was not rare, and the hyponatremia was mainly associated with SIADH. As the hyponatremia could be a life-threatening complication, all patients should be screened for serum electrolytes after TSS.

Adolescent↗
PubMed2006

Metabolic disorders in adult growth hormone deficiency: A study of 110 patients at a single institute in Japan.

The purpose of this study carried out at a single institute in Japan was to investigate the clinical characteristics and complications of patients with adult growth hormone deficiency (GHD). Clinical and biochemical data of 110 patients (50 males, 60 females; mean age 42 +/- 17 yr) with adult GHD who attended Tokyo Women's Medical University between 1990 and 1999 were analyzed retrospectively from medical records. This retrospective analysis demonstrated that 109 patients had multiple pituitary hormone deficiencies, with 98 patients having a deficiency of more than three hormones. Sixty-one patients had childhood onset GHD (COGHD) while the remaining 49 patients had adulthood onset GHD (AOGHD). Body mass index (BMI) ranged from 16.9 to 35.9 with a mean of 23.9 +/- 4.1 (kg/m2), with BMI being > or = 25 kg/m2 in 38 patients (31% of COGHD and 38% of AOGHD). Forty-one percent of the patients had hypercholesterolemia, 41% had hypertriglyceridemia, 47% had decreased levels of HDL cholesterol and 48% had increased levels of LDL cholesterol. Intima-media thickness (IMT) of the carotid arteries was investigated in 33 patients, with abnormal findings including increased IMT or plaque being observed in 4 of 18 COGHD patients and 4 of 15 AOGHD patients. Diabetes mellitus and impaired glucose tolerance was found in 4 COGHD patients and 16 AOGHD patients. Insulin resistance was assessed in 36 patients by the homeostasis model insulin resistance index (HOMA-R) and ranged from 0.65 to 10.58 with a mean of 2.80 +/- 0.37. This mean value of HOMA-R was significantly greater than that measured in normal subjects (1.58 +/- 0.05: P < 0.05). These data suggest that abnormal lipid and glucose metabolism, and atherosclerotic changes occur frequently in adult patients with GHD. Insulin resistance may play a role in glucose and lipid metabolism disorders associated with GHD.

Adolescent↗
PubMed2006

Clinical characteristics, etiologies and pathophysiology of patients with severe short stature with severe GH deficiency: questionnaire study on the data registered with the foundation for growth science, Japan.

In this study, we sent questionnaires to doctors treating severe short stature with severe GH deficiency (GHD) (height SDS (HtSDS) below -4 and all peak GH to provocative stimuli below 2 micro/L) (abbreviated as Severe Case), and obtained effective replies of 51 cases. The clinical characteristics, etiologies, and pathophysiology of these patients were examined. Among the 51 Severe Cases no consanguinity was observed, 44 were IGHD (24 males and 20 females), 3 were GH-1 gene deletion, 2 were Pit-1 gene mutation, and 2 were achondroplasia. HtSDS in these Severe Cases was already remarkably low at 12 (-3.0) and 24 months old (-3.9), while their birth weight and birth length were within normal ranges. Among 44 patients with IGHD, 12 were isolated GHD, and the remaining 32 were combined pituitary hormone deficiency (CPHD). Pituitary MRI was undergone in 25 idiopathic GHD, and abnormal findings (pituitary atrophy, interruption of stalk, and ectopic posterior lobe) were observed in 21 patients with CPHD. More than half of these patients had the history of breech delivery. Three patients with GH-1 gene mutation showed normal pituitary MRI, whereas one of two patients with Pit-1 mutation showed pituitary atrophy and narrowing of pituitary stalk. In conclusion, Severe Cases tended to have CPHD, and the incidence of Severe Case was only 0.6% of total IGHD. Although GHD due to genetic disorders is considered to be extremely rare (0.06% of total IGHD), the incidence reaches high levels (9.8%) among Severe Cases. Growth disorders in these Severe Cases seem to occur soon after delivery. Much earlier diagnosis and hGH treatment are desirable to attain better final height in the Severe Cases. GH-1 and Pit-1 gene analyses are crucial, when genetic abnormalities other than achondroplasia are suspected.

Achondroplasia↗
PubMed2005

Pediatric nonalcoholic steatohepatitis associated with hypopituitarism.

We experienced two cases of pediatric nonalcoholic steatohepatitis (NASH) associated with hypopituitarism. The first patient was diagnosed with a craniopharyngioma at 5 years of age. After an operation to treat the condition, the patient gradually became obese, and an elevation of transaminases was observed. At 16 years of age, the patient was diagnosed as having NASH with liver cirrhosis. He was started on hormone replacement therapy; however, his insulin resistance and liver fibrosis, as evaluated by hyaluronic acid and platelet count, progressed. In addition, his hyperleptinemia continued. The second patient was diagnosed, at 10 years of age, as having pituitary dysfunction due to fetal asphyxia, and he was started on hormone replacement therapy. This patient was noted to have been obese throughout his life. He was diagnosed as having NASH with advanced fibrosis at 18 years of age. It is important for both hepatologists and endocrinologists to be aware of the association between pituitary dysfunction and NASH.

Adiponectin↗
PubMed2005

A nationwide attempt to standardize growth hormone assays.

The Growth Hormone (GH) and Its Related Factors Study Committee of the Foundation for Growth Science, Japan, has been conducting a quality control study for 15 years to improve the equality of diagnosis of GH deficiency. It found that the greatest differences in measured GH values were due to the different potencies of the kit standards, which were primarily adjusted to WHO standards for human GH of pituitary origin. With the collaboration of kit makers and the Study Group of Hypothalamo-Pituitary Disorders of the Ministry of Health, Labor and Welfare, all GH kits in Japan have begun using the same recombinant human GH standard since April 2005. As a result the diagnostic cut-off peak GH has changed from 10 to 6 ng/ml.

Adolescent↗
PubMed2005

Studies of very severe short stature with severe GH deficiency: from the data registered with the foundation for growth science.

The ratio, clinical characteristics, and therapeutic efficacy of hGH treatment in patients with severe short stature (HtSDS below -4SD) with severe GHD (all peak GH values to provocation tests: below 2 mug/L) were studied. From March 1986 to January 1998, 23,110 patients with idiopathic GH deficiency (IGHD) were registered with the Foundation for Growth Science, Japan. These subjects were divided into 5 groups as follows: Group 1 (G1), all subjects; Group 2 (G2), at least one GH peak to provocative test > or = 5 microg/L; Group 3 (G3), 2 microg/L < or = GH peak<5 microg/L; Group 4 (G4), all GH peaks<2 microg/L and HtSDS>-4; Group 5 (G5), all GH peaks<2 microg/L and HtSDS< or = -4. The ratio of G5 was 139 patients (0.6%) out of 23,110 patients with IGHD. In G5, there were no significant differences in birth weight, birth length, gestational age and parental height between G2, G3 and G4. However, asphyxia at delivery was more frequent in G5 and G4 than G2 and G3. Chronological age (CA), bone age (BA) and BA/CA ratio at registration were significantly lower in G5 than G2, G3 and G4. Further, the IGF-I SD score in G5 was significantly lower than those in G2 and G3. After hGH treatment, the final height and final height SDS in G5 remained the lowest, while the DeltaHtSDS value in G5 was the greatest among G2 to G5 groups. In conclusion, the ratio of severe short stature with severe GH deficiency (G5) is only 0.6% of all IGHD cases. Growth failure in G5 seems to occur after birth, and its etiology in G5 seems to be different from that of patients with other forms of IGHD. Early diagnosis and hGH treatment are needed to attain better final height.

Age Determination by Skeleton↗
PubMed2004

Serum adiponectin levels in adult growth hormone deficiency and acromegaly.

Atherosclerosis and insulin resistance are common complications of adult growth hormone deficiency (GHD) and acromegaly. Circulating adiponectin, an adipocyte-derived protein, has both anti-atherogenic and insulin-sensitising effects. In this study, we measured serum adiponectin levels in patients with either adult GHD or acromegaly to clarify the impact of GH secretory states on the regulation of serum adiponectin levels. Serum adiponectin level was measured by radioimmunoassay in 32 patients with adult GHD, 49 patients with acromegaly and 25 normal subjects. The relationships between adiponectin and insulin sensitivity index assessed as quantitative insulin sensitivity check index (QUICKI), BMI, and serum GH and IGF-I levels were then investigated. The values of QUICKI were significantly lower in patients with acromegaly or adult GHD compared to normal subjects (0.33 +/- 0.03, P < 0.01, 0.35 +/- 0.04, P < 0.05 and 0.36 +/- 0.01, respectively). While patients with adult GHD had significantly lower serum adiponectin levels than patients with acromegaly (6.5 +/- 3.9, 9.2 +/- 5.0, P < 0.01) these levels were not significantly different from those found in normal subjects (7.8 +/- 4.3 mug/ml). There was an inverse correlation between serum adiponectin levels and BMI in both patient groups (GHD r = -0.39, P < 0.05; Acromegaly r = -0.35, P < 0.05). However, serum adiponectin levels correlated positively with QUICKI (R(s) = 0.37, P < 0.05) only in patients with adult GHD. In patients with acromegaly, the levels of circulating adiponectin showed an inverse correlation with serum IGF-I levels (R(s) = -0.34, P < 0.05), but not with basal GH levels. These results demonstrate that adiponectin levels are significantly lower in patients with adult GHD than in patients with acromegaly. Adiponectin levels are similar in patients with GHD and healthy controls, whereas in patients with acromegaly, insulin resistance appears to be not closely related to adiponectin levels compared with BMI. The different relationship between adiponectin and QUICKI observed in the adult GHD and acromegaly groups presumably reflects differences in the mechanisms of insulin resistance under states of GH deficiency or excess.

Acromegaly↗
PubMed2004

Plasma levels of intact and degraded ghrelin and their responses to glucose infusion in anorexia nervosa.

Octanoylated ghrelin (1-28) (intact ghrelin) is rapidly and easily degraded to desoctanoyl forms or smaller fragments (degraded ghrelin). Plasma levels of intact and degraded ghrelin were examined in 30 patients with anorexia nervosa (AN) (body mass index, 8.81-22.4 kg/m(2)) and 16 age-matched healthy women using several assay methods. Plasma levels of ghrelin measured using immunocomplex transfer-enzyme immunoassay, which specifically detects intact ghrelin, were lower in AN than controls. Plasma ghrelin levels in AN measured using the active ghrelin ELISA kit, which is advertised as specifically detecting intact ghrelin, did not differ significantly from controls. Plasma levels of desoctanoyl ghrelin using the desacyl-ghrelin ELISA kit, N-terminus ghrelin using the ghrelin active RIA kit, and C-terminus ghrelin using the ghrelin total RIA kit were significantly higher in AN than controls, and displayed significant negative correlations with body mass index. Plasma levels of ghrelin determined using immunocomplex transfer-enzyme immunoassay or active ghrelin ELISA during iv glucose infusion were suppressed in both AN and controls, whereas plasma levels of degraded ghrelin levels were not significantly decreased in AN. Plasma levels of intact ghrelin are therefore not higher in AN than controls, whereas degraded forms of ghrelin are elevated in AN. Rapid suppression of plasma intact ghrelin, but not degraded ghrelin, occurs in AN in response to glucose infusion. The profiles of intact and degraded forms of ghrelin in plasma of AN patients differ from those of healthy women.

Adolescent↗
PubMed2004

Severe hypoglycemia and hypokalemia in association with liver metastases of gastric cancer.

We report an 80-year-old man who presented with non-islet cell tumor hypoglycemia (NICTH) in association with hepatic recurrence of gastric cancer. His serum potassium was reduced from 3.9 to 3.1 mmol/l 5 weeks after gastrectomy, and he subsequently developed hypoglycemic coma. He was diagnosed as having NICTH because of the presence of serum big IGF-II and positive staining for IGF-II in gastric cancer cells obtained at surgery. A computed tomography showed multiple liver metastases. His hypoglycemia was refractory to steroid therapy. This case suggested that NICTH could develop in association with hepatic metastases of gastric cancer. Unexpected hypokalemia may be a manifestation of occult NICTH.

Adenocarcinoma↗
PubMed2004

High molecular weight form insulin-like growth factor II-producing mesenteric sarcoma causing hypoglycemia.

An 81-year-old woman presented with frequent episodes of hypoglycemia. Her serum level of insulin was normal, but her serum insulin-like growth factor (IGF)-II level was high. She was found to have a spindle cell sarcoma originated from the mesentery of the sigmoid colon, which was completely resected. Postoperatively, hypoglycemia ameliorated with concomitant reduction in serum IGF-II levels. Immunohistochemical study revealed positive immunostaining for IGF-II in tumor cells, and the abundant expression of IGF-II mRNA was demonstrated by RT-PCR. The presence of high molecular weight (HMW) form IGF-II in patient's serum was confirmed by immunoblotting. This is the first report of a patient with HMW form IGF-II-producing mesenteric sarcoma causing hypoglycemia.

Aged↗
PubMed2003

Oral DDAVP is a good alternative therapy for patients with central diabetes insipidus: experience of five-year treatment.

We studied the efficacy and safety of oral 1-deamino-8-D-arginine-vasopressin (DDAVP) tablets in 9 patients, aged 17-36 years, with central diabetes insipidus (DI). The tablet contained 100 microg of desmopressin acetate. Maximum plasma concentration was obtained at 90 min after a single oral administration of 100 microg DDAVP with a mean plasma level of 14.7 +/- 5.4 (range: 5.3-50.9) pg/ml. The onset of action was observed 2 h after oral administration, while the maximum effect was obtained at 4 h. Mean urine volume in patients decreased significantly from 402 +/- 52 to 26 +/- 3 ml/hr and urine osmolality increased from 91 +/- 8 to 732 +/- 21 mosm/kg at 4 h after the intake of oral DDAVP. Plasma osmolality level and serum sodium concentration remained unchanged throughout the study. Long-term treatment for 5 years with oral DDAVP resulted in control of diuresis in 8 of the 9 patients. The average oral DDAVP dose required to obtain this control was 19 +/- 2 (range: 15-30) times more than that of prior intranasal treatment. No adverse effects were observed during this follow-up period. These results indicate that oral DDAVP is a safe therapeutic agent that may be a good alternative treatment of central DI, particularly in patients who have chronic rhinitis and visual disturbances.

Administration, Oral↗
PubMed2003

Hypoglycemia associated with big insulin-like growth factor II produced during development of malignant fibrous histiocytoma.

We describe a rare case of hypoglycemia associated with a high molecular weight form of insulin-like growth factor II (big IGF-II) produced during the development of malignant fibrous histiocytoma (MFH). A 66-year-old man was referred to our department for further evaluation of hypoglycemia. At the age of 59, he had been diagnosed as having a MFH in the retroperitoneum, and underwent incomplete resection of the tumor. He had no symptoms of hypoglycemia at that time. Within the last few years, he developed symptoms of hypoglycemia in the early morning. Computerized tomography scans of the abdomen showed multiple tumors around the peritoneum and the liver. Serum insulin levels were decreased although no other hormonal deficiencies were observed. Serum IGF-II levels were elevated as a result of big IGF-II production. Taken together, these results indicated that hypoglycemia in this patient was associated with the production of big IGF-II by the MFH. The most effective therapeutic modality in patients with non-islet cell tumor hypoglycemia is resection of the tumor. In our case, as complete resection was impossible, dexamethasone and glucagon were administered and proved to be effective for preventing hypoglycemia.

Aged↗