Biomedical subjects

T Koh

Publications and source records attributed to T Koh.

At least 19 recordsLinked to original sources

PubMed1992

Transient patterns of serotonergic innervation in the rat visual cortex: normal development and effects of neonatal enucleation.

The transient aggregation of serotonin (5-HT)-containing fibers in the early development of rat visual cortex was examined immunohistochemically. The aggregation of 5-HT immunoreactive (IR) fibers consisted of three stages which were classified according to the course of time and degree of space occupied. The primary aggregation appeared in the subplate and moved upward along the development of the cortex. The aggregation proceeded to the secondary stage in presumptive layer IV. The fibers extended in a column-like structure following the secondary aggregation and formed the tertiary aggregation. The upper edge of the tertiary aggregation formed a lattice-like pattern in layer I and its structure was recognized to be similar to the structure of a 'blob' which characterizes the primary visual cortex in monkey. This transient aggregation of 5-HT-IR fibers began in the subplate of the anterior visual cortex on postnatal day 2 (PND 2) and progressed towards the posterior. On PND 11, the secondary and tertiary aggregations were completed in the entire region. No further aggregation of 5-HT-IR fibers was observed on PND 15. The anterior-to-posterior axis in the aggregation process corresponds to the direction of differentiation in the layer structure of cortex. In order to investigate the relationship between the transient aggregation of 5-HT-IR fibers and the development of the visual pathway, the secondary and tertiary aggregation on PND 11 were observed after postnatal monocular or binocular enucleation. Enucleation of eye balls did not affect either the area occupied by the 5-HT-IR fibers in the secondary aggregation or the number of column structures in the tertiary aggregation. However, the contralateral and ipsilateral cortices of monocularly enucleated cases were irregularly shaped in the secondary aggregation. The distribution of 5-HT-IR fiber terminals in the binocular area (Oc1B) increased in density on the contralateral side in the monocular enucleation, while that of both sides in the binocular enucleation was of non-homogeneous density and were shaped irregularly. The above results suggest that the transient aggregation of 5-HT-IR fibers observed in the early stage of development of visual cortex is regulated primarily by the intrinsic factors, and that extrinsic factors, such as visual pathway input, affect the aggregation within the boundary of such intrinsic factors. That is, the visual pathway input and the input balance from both eyes affect the distribution density of 5-HT-IR fibers and the shape of the visual cortex, respectively.

Animals↗

PubMed1992

Metastatic renal cell carcinoma to the pituitary gland presenting with hypopituitarism.

A 57-year-old man with pituitary metastasis from renal cell carcinoma is reported. He underwent right nephrectomy and total pancreatectomy for renal cell carcinoma and its pancreatic metastasis, respectively. Imaging studies showed an intrasellar mass lesion. The examination revealed panhypopituitarism, diabetes insipidus and bitemporal hemianospia. Metastatic renal cell carcinoma was diagnosed by the biopsy of the pituitary tumor. Metastatic renal cell carcinoma to the pituitary gland, which is extremely rare, appears to have unique features of presenting with hypopituitarism and visual disturbance more frequently than other metastatic pituitary tumors.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1992

Dual-site thyroid ectopy in a mother and son.

We found familial thyroid ectopy in a mother and son, each of whom had an anterior neck mass corresponding to a perihyoid ectopic thyroid. In addition, technetium scintigraphy revealed another focus of aberrant uptake at their tongue roots. Neither patient showed hypothyroid symptoms or abnormal biochemical data other than a mildly elevated TSH level in the son. No other member of the family had a thyroid disorder. To our knowledge this is the first documented instance of familial thyroid ectopy in multiple sites. The observed similarity in distribution of ectopic tissue suggests a hereditary pathogenic factor.

Adult↗

PubMed1992

Chondroid chordoma presenting with hypopituitarism.

A 28-year-old man with chondroid chordoma, an uncommon variant of chordoma, is reported. The patient presented with visual disturbance and hypopituitarism. The latter is a rare complication of intracranial chordoma. The preoperative diagnosis of chondroid chordoma of the skull base was based on unique findings on computed tomography and magnetic resonance imaging studies. The development of the tumor over six years suggests that the prognosis of chondroid chordoma may be poor in younger patients, as recently reported. Although chondroid chordoma is very rare, it should be included in the differential diagnosis of hypopituitarism.

Adult↗

PubMed1992

[Decrease of CD16 antigen density on granulocytes in chronic myeloid leukemia].

We examined the fluorescence intensity of CD16 antigen, which represents the density of CD16 antigen, on granulocytes by flow cytometry in 15 healthy subjects and 15 patients with neutrophilia due to inflammatory diseases and 10 patients with chronic myeloid leukemia (CML). The fluorescence intensity of CD16 antigen was significantly lower in patients with CML than in healthy subjects and also than in patients with neutrophilia. These data indicate that 1) density of CD16 antigen on granulocytes decrease in CML, and 2) analysis on the density of granulocyte CD16 antigen is useful for differential diagnosis of CML from inflammatory diseases with neutrophilia.

Flow Cytometry↗

PubMed1992

[Transient patterns of serotonergic innervation in the rat visual cortex--normal development and effects of enucleation].

Serotonergic innervation formed transient dense aggregation in all rat primary sensory areas during early postnatal development. In the normal rat visual cortex, there were three stages in the transient aggregation of serotonin immunoreactive fibers from postnatal day (PND) 2 to 15. Primary aggregates appeared in the subplate prior to the differentiation of layer IV, and moved upward to the lower layer of cortical plate to form secondary aggregates. Secondary aggregation gave rise to ascending fibers on the cortical surface which were roughly grouped in columns (tertiary aggregation). The serotonin fibers of the tertiary aggregates were arranged in a lattice-like pattern in layer I, and were significantly altered either in size of distribution area or column number after monocular or binocular enucleation. These data indicate that the lattice-like pattern of serotonin innervation in neonatal rats may be an evolutionary precursor of the "blobs" seen in the higher primates.

Animals↗

PubMed1992

[A case of primary pulmonary paraganglioma].

A case of primary paraganglioma of the lung in a 48-year-old woman is presented. She was found to have a coin lesion in lower lobe on routine radiography. Results of bronchoscopic examination were negative, and exploratory right thoracotomy was performed. At operation, non-invasive encapsulated tumor found in posterior basal segment of the right lower lobe was enucleated. Histological analysis of the resected tumor proved to be compatible with pulmonary paraganglioma. Pulmonary paraganglioma is said extreme rare, and so only 21 cases were previously reported in the literature including this case.

Female↗

PubMed1991

Limited value of delayed radiothallium image in the diagnosis of nodular goiter.

To test whether delayed thallium image can improve the diagnostic accuracy of thyroid tumor, we have reviewed 35 patients with cold nodules of proven histopathology. Early and delayed images were taken 10-20 min and 3-4 hr postinjection, respectively. In this study, a thyroid nodule was interpreted as malignant if it had normal or increased uptake on early scan and more residual radioactivity than paranodular tissue on delayed scan. In the eighteen patients who had carcinoma, a disappointing 44% false negative rate was observed. No significant difference was seen between retention-positive and negative cases in tumor size or histological type of cancer. Nor could any demographic bias explain the low sensitivity. Of the six false negatives, macroscopic cystic degeneration was seen in two cases, but tumors in the other four were grossly solid. Considering the histological heterogeneity often seen within a thyroid tumor, the portion with increased retention of radiothallium may be too small to be detected in the false negative cases. Furthermore, 3 false positive readings were obtained in 17 patients with benign conditions. We conclude that the contribution of the delayed thallium image was quite limited in predicting or ruling out malignancy in nodular goiters.

Adult↗

PubMed1991

False aneurysm formation of the great arteries after arterial switch operation.

An infant with simple transposition of the great arteries underwent a two-staged arterial switch operation, after which mediastinal infection occurred. Continuous irrigation with povidone-iodine solution was performed for 10 days. After that, the patient experienced life-threatening hemorrhage three times. At the time of the second hemorrhage, greater omental transfer was performed. On postoperative day 109, false aneurysm was recognized, having developed from both great arteries. Successful repair was performed on postoperative day 110.

Aneurysm↗

PubMed1991

Investigations of origins of serotonergic projection to developing rat visual cortex: a combined retrograde tracing and immunohistochemical study.

The present study investigated whether the raphe neurons which give rise to the transient serotonergic fibers in the visual cortex of neonatal rats persist or disappear as the rats mature. Three experiments were performed employing the WGA-apoHRP-Au retrograde transport technique in conjunction with 5-HT or WGA-HRP immunohistochemical staining. WGA-apoHRP-Au was injected into the primary visual cortex of all rats 9 days postnatally. In the first experiment, the animals were examined after 2 days; retrogradely labeled cells were observed in the dorsal raphe nucleus (DR), the median raphe nucleus (MR), and in the B9 and B6 cell groups; the majority (82.5%) of the cells was serotonergic. In the second experiment, the examinations took place following a survival time of 8 weeks: virtually all of the original raphe-visual cortical serotonergic neurons were found to the present. In the third experiment, also performed after 8 weeks relabeling the raphe-visual cortical neurons by WGA-HRP, it was found that 37.2% of the raphe neurons which had projected to the neonatal visual cortex no longer possessed such projections.

Aging↗

PubMed1991

[Prediction of remission in Graves' disease after thionamide therapy by technetium-99m early uptake].

In the clinical management of Graves' thyrotoxicosis, one of the most important subject is when to stop antithyroid drugs after achieving an euthyroid state. T3 suppression test and other methods have been used to forecast the outcome after drug cessation, but the results were not always satisfactory. We have attempted to predict remission of Graves' disease by single measurement of early technetium uptake without administration of triiodothyronine. Drugs were discontinued in the seventy-five patients with Graves' disease on maintenance doses of either methimazole or propylthiouracil who showed normalized uptake (4.0% or less). Of 64 patients evaluable after twelve months, 55 (86%) remained euthyroid, 8 relapsed, and 1 became hypothyroid. With its accuracy in prediction of short-term remission comparable or superior to T3 suppression test, this rapid and simple method seemed suitable for routine use in clinical practice.

Adult↗

PubMed1991

Significant non-serotonergic raphe projection to the visual cortex of the rat. An immunohistochemical study combined with retrograde tracing.

The present study investigated the distribution of serotonergic and non-serotonergic raphe neurons with direct projections to the visual cortex. The study employed the WGA-apoHRP-Au retrograde transport technique combined with 5-HT immunohistochemical staining. Retrogradely labeled cells were observed in the dorsal raphe nucleus, the median raphe nucleus, and in the B9 and B6 cell groups. One notable finding was the great number of retrogradely labeled, non-5-HT immunoreactive cells. The average percentages of such cells in the various raphe regions were as follows: DR: 52% (n = 401); MR: 35% (n = 311); B9: 24% (n = 129); B6: 95% (n = 200). The present study demonstrated the presence of a significant proportion of non-serotonergic raphe region neurons projecting to the primary visual cortex in the rat. It is suggested that these neurons may complement the aminergic neurons as part of the ascending system which controls the functions of the visual cortex.

Animals↗

PubMed1991

[Mixed type cryoglobulinemia with discrepancy of platelet counts measured with an automated cell counter and by manual counting method].

We experienced an abnormal blood sample which showed larger numbers of white blood cells and platelets counted by the electric resistance system and of platelets in mechanical counting by the flow system, than those in manual counting. Many precipitates were observed in this blood sample at room temperature or 4 degrees C, but were not observed at 37 degrees C. The precipitates were clarified to be caused by the mixed type (IgA, IgG and IgM) cryoglobulin by using an immunofluorescence method and an ouchterlony method. These data indicate that precipitation of cryoglobulin at room temperature induce falsely high value of platelet count in mechanical counting systems.

Chemical Precipitation↗

PubMed1991

[A double-labeling study of serotonin neurons that project to the visual cortex of developing rat brain].

Immunohistochemical studies of developing rat brains revealed aggregation of serotonin terminal fibers in the visual cortex at from 7 to 14 postnatal days. This aggregation is transient, disappearing 2 weeks after birth. The cells of origin of these serotonin terminals were investigated using double-labeling with retrogradely transported WGA-apoHRP-Au and serotonin immunohistochemistry. WGA-apoHRP-Au was injected into the rat visual cortex on the 9th day after birth. The rats were allowed to survive for 2 days and sacrificed with perfusion. Cryostat sections of the brain were processed with silver-enhancement to develop the retrogradely transported WGA-apoHRP-Au, and then serotonin immunohistochemistry was performed. Double-labeled cells that were labeled with WGA-apoHRP-Au and serotonin-immunoreactive were found mostly in the raphe medianus and raphe dorsalis in rostral and caudal sections of the mesencephalon, respectively.

Animals↗

PubMed1991

[The early detection of metastatic differentiated thyroid cancer using 131I total body scan and treatment with 131I].

With the purpose of achieving early detection and performing 131I therapy for metastatic lesions of differentiated thyroid cancer, we studied the clinical findings in 132 patients who underwent 131I total body scanning (131I TBS) between 1981 and 1990. Metastatic lesions were detected only by 131I TBS in 24 (18%) of the 132 patients. Of the 49 patients treated with 131I for metastases, 27 (55%) underwent total thyroidectomy and then had their metastatic lesions treated by 131I less than one year later. In the remaining 22 patients (45%), the metastatic lesions were treated with 131I from 1 to 31 years (mean: 8.4 years) after the initial thyroidectomy. We determined the optimal timing of 131I TBS following radical thyroidectomy to be 3-4 weeks by sequential measurement of the serum thyroid hormones, TSH, and Tg, and determination of the 123I uptake in residual or metastatic cancer of the neck after thyroidectomy. 131I TBS with simultaneous serum Tg determination were performed in 52 patients with metastases. Scans were positive in 43 of the 52 (83%) and the serum Tg level was greater than 10 ng/ml in 46 of the 52 (88%). Serum Tg was elevated in 9 patients with negative scans, while low Tg levels were found in 6 patients with positive scans. 131I therapy was effective in 49 of the 65 treated patients (75%), including 5 cures. Two patients worsened and 6 died. These 8 patients were all older than 56 years of age. Post-therapeutic 131I TBS demonstrated unsuspected metastatic lesions in 7 patients and had a higher detection rate for metastatic lesions than diagnostic 131I TBS. We conclude that 131I TBS with simultaneous Tg determination should be performed to detect metastatic lesions in all patients following positively total thyroidectomy for differentiated thyroid cancer, and that 131I treatment should be given when positive 131I uptake is detected in metastatic or residual cancer.

Adenocarcinoma↗

PubMed1990

Thyrotoxic Graves' disease with normal thyroidal technetium-99m pertechnetate uptake.

We saw 24 thyrotoxic Graves' patients with normal thyroidal uptake of technetium-99m pertechnetate (99mTc) out of 201 untreated thyrotoxic Graves' patients seen over 4 years. The clinical and laboratory findings for these patients were studied and analysed. Thyroid uptake and scintigraphic examinations by means of 99mTc, TBII and TSab activity measurement clearly distinguished these patients from other thyrotoxic disorders (destruction-induced thyrotoxicosis and autonomously functioning thyroid lesions). Different from other disorders, these patients had not lower but normal thyroid uptake and also showed diffuse and discrete trapping into the enlarged glands. These patients had significantly smaller goiters, a lower serum thyroid hormone level, and lower TBII and TSab activity, when compared with other high 99mTc uptake groups with Graves' disease, and their condition could be easily controlled with small amounts of antithyroid drugs. Our study indicates that thyrotoxic Graves' disease with normal 99mTc uptake exists and 99mTc uptake study and TBII activity measurement is very useful for the diagnosis. The normal 99mTc uptake thyrotoxic Graves' patient might be early stage patients with general Graves' disease and their early discrimination from general Graves' patients is very advantageous for treatment and prognosis.

Adult↗

PubMed1990

Digoxin-like immunoreactivity in Chinese medicine.

Immunoreactive digoxin-like activity was observed in Chinese medicine, KYUSHIN tablet, taken popularly in Japan without prescription. The antibodies used in the assays of digoxin reacted with Chan-su, the major effective component of KYUSHIN, which contained cardiotonic steroids with similar chemical structure as digoxin. One tablet of KYUSHIN had digoxin-like immunoreactivity equivalent to 1.9, 1.5, and 72 micrograms of digoxin measured by three different commercial kits. These different equivalences may be attributed to differences in cross-reactivity of the antibody used in the immunoassays. Two healthy volunteers took two KYUSHIN tablets three times a day, a typical dose, and digoxin-like immunoreactivity reached almost 0.4 micrograms/L in 0.5 day. Therapeutic drug monitoring should be interpreted carefully in patients taking Chinese medicines, many of which contain the Chan-su component.

Cross Reactions↗

PubMed1990

Effects of repetitive administration of corticotropin-releasing hormone combined with lysine vasopressin on plasma adrenocorticotropin and cortisol levels in secondary adrenocortical insufficiency.

To examine the functioning of the hypothalamo-pituitary-adrenocortical axis in secondary adrenocortical insufficiency, we administered 100 micrograms synthetic human CRH, iv, plus 10 U lysine-8-vasopressin (LVP), im, three times daily for 3 consecutive days. The changes in plasma ACTH and cortisol levels during the administration and the response to an insulin tolerance test (ITT) conducted before and after the administration were determined. In three patients with isolated ACTH deficiency, basal plasma ACTH and cortisol levels were undetectablly low, and there was no response noted in the ITT or during CRH-LVP administration throughout the observation period. In four patients with adrenocortical insufficiency who had undergone successful transsphenoidal microadenomectomy for Cushing's disease and in six patients who had undergone curative unilateral adrenalectomy for Cushing's syndrome, basal plasma ACTH levels were low, but responded considerably to both stimulation tests. Along with the 3 days of CRH-LVP stimulation, however, neither the peak nor the time-integrated ACTH response was significantly enhanced, because of the variability of the responses among the patients. Compared with the ACTH response on the last day of CRH-LVP stimulation, the subsequent ITT tended to induce a lower ACTH response in the post-Cushing's disease patients and a higher response in the post-Cushing's syndrome patients. Regarding the plasma cortisol levels, the basal, peak, and integrated responses tended to increase daily during CRH-LVP administration. Conversely, the ITT after repetitive CRH-LVP administration induced a higher cortisol response than the test before CRH-LVP administration in the post-Cushing's disease patients. No serious complications were noted in any of the patients during or after the treatment. The present findings indicate that 1) repetitive administration of CRH in combination with LVP is a safe and valuable provocation test to examine the pituitary ACTH reserve and the integrity of the pituitary-adrenocortical axis; 2) isolated ACTH deficiency is usually due to a defect at the pituitary level; 3) with respect to adrenocortical responsiveness, post-Cushing's disease patients show a better accumulation of the provocative effect than do post-Cushing's syndrome patients; and 4) both hypothalamic and pituitary dysfunction are responsible for adrenal hypofunction in patients after hypercortisolemia, but post-Cushing's syndrome patients (especially those with a short period of hypercortisolemia) appeared to have less impairment of hypothalamic ACTH-releasing activity than post-Cushing's disease patients.

Adrenal Cortex↗