GABA(B) receptors function as a heteromeric assembly of the subunits GABA(B)R1 and GABA(B)R2

The principal inhibitory neurotransmitter GABA (gamma-aminobutyric acid) exerts its effects through two ligand-gated channels, GABA(A) and GABA(C) receptors, and a third receptor, GABA(B) , which acts through G proteins to regulate potassium and calcium channels. Cells heterologously expressing the cloned DNA encoding the GABA(B)R1 protein exhibit high-affinity antagonist-binding sites, but they produce little of the functional activity expected from studies of endogenous GABA(B) receptors in the brain. Here we describe a new member of the GABA(B) polypeptide family, GABA(B)R2, that shows sequence homology to GABA(B)R1. Neither GABA(B)R1 nor GABA(B)R2, when expressed individually, activates GIRK-type potassium channels; however, the combination of GABA(B)R1 and GABA(B)R2 confers robust stimulation of channel activity. Both genes are co-expressed in individual neurons, and both proteins co-localize in transfected cells. Moreover, immunoprecipitation experiments indicate that the two polypeptides associate with each other, probably as heterodimers. Several G-protein-coupled receptors (GPCRs) exist as high-molecular-weight species, consistent with the formation of dimers by these receptors, but the relevance of these species for the functioning of GPCRs has not been established. We have now shown that co-expression of two GPCR structures, GABA(B)R1 and GABA(B)R2, belonging to the same subfamily is essential for signal transduction by GABA(B) receptors.

Technetium-99m-HMPAO brain SPECT in neonates with hypoglycemic encephalopathy

Regional brain injury in three neonates with hypoglycemic encephalopathy are presented using serial 99mTc-hexamethyl propyleneamine oxime (HMPAO) SPECT and, for comparison, MRI. During the acute stage, both 99mTc-HMPAO SPECT and MRI reveal abnormalities in the posterior cerebrum. Technetium-99m-HMPAO SPECT reveals further areas of insult, for example the frontal lobes. The degree of hypoperfusion correlates with the clinical severity of hypoglycemia during the neonatal period and subsequent neurological sequelae. Follow-up with HMPAO SPECT several months after insult demonstrates persistent hypoperfusion in some areas, mainly in the occipital and posterior parietal regions. MRI can depict morphological changes with superior resolution. Because morphological change generally follows slowly after functional change, MRI is less sensitive than HMPAO SPECT in detecting and predicting the extent of hypoglycemic cerebral injury during the acute phase. HMPAO SPECT during the acute stage is a valuable tool for evaluating the extent and severity of brain injury in neonates with hypoglycemic encephalopathy.

Cloned human and rat galanin GALR3 receptors. Pharmacology and activation of G-protein inwardly rectifying K+ channels

The neuropeptide galanin has been implicated in the regulation of processes such as nociception, cognition, feeding behavior, and hormone secretion. Multiple galanin receptors are predicted to mediate its effects, but only two functionally coupled receptors have been reported. We now report the cloning of a third galanin receptor distinct from GALR1 and GALR2. The receptor, termed GALR3, was isolated from a rat hypothalamus cDNA library by both expression and homology cloning approaches. The rat GALR3 receptor cDNA can encode a protein of 370 amino acids with 35% and 52% identity to GALR1 and GALR2, respectively. Localization of mRNA by solution hybridization/RNase protection demonstrates that the GALR3 transcript is widely distributed, but expressed at low abundance, with the highest levels in the hypothalamus and pituitary. We also isolated the gene encoding the human homologue of GALR3. The human GALR3 receptor is 90% identical to rat GALR3 and contains 368 amino acids. Binding of porcine 125I-galanin to stably expressed rat and human GALR3 receptors is saturable (rat KD = 0.98 nM and human KD = 2.23 nM) and displaceable by galanin peptides and analogues in the following rank order: rat galanin, porcine galanin approximately M32, M35 approximately porcine galanin-(-7 to +29), galantide, human galanin > M40, galanin-(1-16) > [D-Trp2]galanin-(1-29), galanin-(3-29). This profile resembles that of the rat GALR1 and GALR2 receptors with the notable exception that human galanin, galanin-(1-16), and M40 show lower affinity at GALR3. In Xenopus oocytes, activation of rat and human GALR3 receptors co-expressed with potassium channel subunits GIRK1 and GIRK4 resulted in inward K+ currents characteristic of Gi/Go-coupled receptors. These data confirm the functional efficacy of GALR3 receptors and further suggest that GALR3 signaling pathways resemble those of GALR1 in that both can activate potassium channels linked to the regulation of neurotransmitter release.

Effervescent gallbladder: sonographic findings in emphysematous cholecystitis

We report a case of emphysematous cholecystitis with the sonographic appearance of an "effervescent gallbladder"--a large amount of gas bubbles rising like bubbles in a glass of champagne from the dependent part of the gallbladder and floating to the nondependent part. The etiology of this finding was acute obstruction of the distal common bile duct by a stone and purulent cholangitis. Short-term follow-up sonography is important to confirm the diagnosis of cholecystitis.

Relationship between glycosylated hemoglobin, blood pressure, serum lipid profiles and body fat distribution in healthy Chinese

Obesity-related metabolic disorders have not been adequately addressed due to a failure to distinguish the importance of general obesity or body fat distribution in relation to atherosclerotic risk factors, especially in the less obese populations. To assess the relationship between general obesity (reflected by BMI, total body fat percentage and total adiposity), body fat distribution (reflected by WHR, default regions and ROIs of DEXA) and atherosclerotic risk factors in the Chinese population, a total of 872 healthy subjects (477 male and 395 female) were enrolled in the study. The results indicated that the android pattern of fat distribution, independent of general obesity, was positively correlated with blood pressure, atherogenic indices, fasting and OGTT 2-h plasma glucose, glycosylated hemoglobin (HbA1c), serum concentration of cholesterol, triglyceride, LDL cholesterol and negatively correlated with HDL cholesterol in both genders. The gender differences in patterns of body fat distribution and atherosclerotic risk factors remained significant after adjustments were made for age, BMI and total adiposity, although diminished after further adjustments for body fat distribution. In conclusion, body fat distribution, rather than general obesity, is more correlated with obesity-related atherosclerotic risk factors and sex-associated differences. ROIs measured by DEXA may be a useful method to evaluate sex-associated changes in body fat distribution and atherosclerotic risk factors in the healthy Chinese population.

The value of 67Ga-citrate scanning in psoas abscess

Psoas abscess is a serious health problem which presents with non-specific symptoms and signs. To reduce morbidity and mortality, it is important to diagnose the presence and extent of a psoas abscess accurately using imaging studies. Because the 67Ga scan may facilitate the early diagnosis of insidious infection and assist CT-guided percutaneous drainage of the abscess, we examined the value of 67Ga scans in 18 patients with psoas abscess. The imaging results of 67Ga scans (18 patients), computed tomography (CT) (16 patients) and bone scans (13 patients) were analyzed. In this series, concomitant infections were very common (94%) in patients with psoas abscess. For detecting psoas abscess, the sensitivity of 67Ga scanning (92%) and CT (91%) was similar. However, 67Ga scanning is superior to CT in demonstrating concomitant infectious foci at other sites. Bone scanning is a sensitive tool for depicting osteomyelitis, which was common in this series of patients. We also found that increased vascularity in the psoas area was demonstrated by three-phase bone scanning in 60% of patients.

Long-term vegetarian diet and bone mineral density in postmenopausal Taiwanese women

This study examined bone density among postmenopausal Buddhist nuns and female religious followers of Buddhism in southern Taiwan and related the measurements to subjects characteristics including age, body mass, physical activity, nutrient intake, and vegetarian practice. A total of 258 postmenopausal Taiwanese vegetarian women participated in the study. Lumbar spine and femoral neck bone mineral density (BMD) were measured using dual-photon absorptimetry. BMD measurements were analyzed first as quantitative outcomes in multiple regression analyses and next as indicators of osteopenia status in logistic regression analyses. Among the independent variables examined, age inversely and body mass index positively correlated with both the spine and femoral neck BMD measurements. They were also significant predictors of the osteopenia status. Energy intake from protein was a significant correlate of lumbar spine BMD only. Other nutrients, including calcium and energy intake from nonprotein sources, did not correlate significantly with the two bone density parameters. Long-term practitioners of vegan vegetarian were found to be at a higher risk of exceeding lumbar spine fracture threshold (adjusted odds ratio = 2.48, 95% confidence interval = 1.03-5.96) and of being classified as having osteopenia of the femoral neck (3.94, 1.21-12.82). Identification of effective nutrition supplements may be necessary to improve BMD levels and to reduce the risk of osteoporosis among long-term female vegetarians.

Quantification of serial tumor glucose metabolism

We developed a method to improve the quantitative precision of FDG-PET scans in cancer patients. The total-lesion evaluation method generates a correlation coefficient (r) constrained Patlak parametric image of the lesion together with three calculated glucose metabolic indices: (a) the total-lesion metabolic index ("KT-tle", ml/min/lesion); (b) the total-lesion voxel index ("VT-tle", voxels/lesion); and (c) the global average metabolic index ("KV-tle", ml/min/voxel).

METHODS

The glucose metabolic indices obtained from conventional region of interest (ROI) and multiplane evaluation were used as standards to evaluate the accuracy of the total-lesion evaluation method. Computer simulations and four patients with metastatic melanoma before and after chemotherapy were studied.

RESULTS

Computer simulations showed that the total-lesion evaluation method has improved precision (% s.d. < 0.6%) and accuracy (approximately 10% error) compared with the conventional ROI method (% s.d. approximately 5%; approximately 25% error). The KT-tle and VT-tle indices from human FDG-PET studies using the total-lesion evaluation method showed excellent correlations with the corresponding values obtained from the conventional ROI methods and multiplane evaluation (r approximately 1.0) and CT lesion volume measurements.

CONCLUSION

This method is a simple but reliable way to quantitatively monitor tumor FDG uptake. The method has several advantages over the conventional ROI method: (a) less sensitive to the ROI definition, (b) no need for image registration of serial scan data and (c) includes tumor volume changes in the global tumor metabolism.

Significance of urinary tissue polypeptide specific antigen (TPS) determination in patients with urothelial carcinoma

Tissue polypeptide specific antigen (TPS) is the M3 epitope of the tissue polypeptide antigen, and a specific epithelial proliferation marker. To examine the benefit of urine TPS (UTPS) measurement in the diagnosis and classification of biological properties of transitional cell carcinoma (TCC), a radioimmunoassay of U-TPS was measured in patients with active TCC (n = 56), at tumor-free status (n = 36), with inflammatory urological disease (n = 44), and age-sex adjusted normal subjects (n = 75). Both neoplastic and inflammatory urological diseases had an increase in U-TPS levels (U/gm creatinine) compared to normal individuals (p = 0.0005), while it normalized in tumor-free condition (p = 0.007). For patients with active TCC, a strong positive association was observed between U-TPS values and both histological grading (p = 0.05) and positive cytology (p = 0.05). U-TPS levels were significantly higher in the presence of nodal or systemic metastasis (p = 0.008 by ANOVA test). Measurement of U-TPS appeared to be an indicator of poor outcome for patients with bladder cancer (p = 0.05 by t test) for a mean follow-up of 26 months. The results indicate that determination of U-TPS can be a supplement in assessing the biological properties of TCC, and may be helpful in identifying patients who need meticulous peri-operative staging survey.

Detection of pelvic deep vein thrombosis by subcutaneous radionuclide venography utilizing an acupuncture point

The authors present a case of thrombosis involving the right common iliac vein evaluated with subcutaneous radionuclide venography (SCRNV) after injection at acupuncture points. SCRNV demonstrated interruption of venous flow to the right common femoral vein and right iliac vein with prominent collateral venous drainage into the contralateral deep veins. This technique, which is technically simple and relatively operator-independent, has the potential to become a screen or follow-up test for deep vein thrombosis.

Tc-99m sestamibi scanning in the preoperative localization of mediastinal parathyroid adenomas

We report on two patients with mediastinal parathyroid adenomas who underwent preoperative Tc-99m sestamibi scintigraphy. Excellent physical characteristics of technetium and slow washout of Tc-99m sestamibi made possible clear delineation of mediastinal parathyroid adenomas by Tc-99m sestamibi imaging.

Ultrasonographic evaluation of multicystic dysplastic kidney

Eleven cases of multicystic dysplastic kidney (MCDK) in children were diagnosed over an 11 year period. All underwent postnatal ultrasound (US) studies. Four different patterns of MCDK were recognized: (1) Six cases presented with the classic sonogram of multicystic components. (2) Three cases had hydronephrotic form; correct diagnosis between hydronephrotic form of MCDK and hydronephrosis was difficult as there was a medially-located, large, lobulated cyst and there was connection between the large cyst and neighboring small cysts. (3) One case initially presented with normal renal sonogram but a small cyst appeared on follow up sonogram and there was also decreased renal size and increased echogenecity. (4) One case had only two moderate-sized cysts but no identifiable renal parenchyma. Two cases had follow-up US examination and one dysplastic kidney decreased in renal size on follow-up sonogram. Intravenous urography and radionuclide study revealed both these dysplastic kidneys to be nonfunctioning. Nine children had surgical resection of the diseased kidneys. Contralateral renal anomalies were detected in five children, which included ureteropelvic junction stenosis, ureterovesical junction stenosis, distal ureteral stenosis and polycystic kidney disease. Two of three hydronephrotic forms of MCDK had contralateral ureteral stenosis. Two of six classic forms of MCDK had contralateral ureteral stenosis. The proportion of contralateral ureteral stenosis was higher in the group of hydronephrotic forms of MCDK. Ultrasonography is beneficial for conclusive diagnosis of MCDK; however, a differential diagnosis of simple hydronephrosis needs to be considered.

Quantitative PET imaging of bone marrow glucose metabolic response to hematopoietic cytokines

To evaluate the effects of hematopoietic cytokines on bone marrow glucose metabolism noninvasively, we studied serial quantitative FDG-PET images in 18 patients with metastatic melanoma and normal bone marrow who were undergoing granulocyte-macrophage colony-stimulating factor (GMCSF) or macrophage colony-stimulating factor (MCSF) administration as an adjunct to chemotherapy.

METHODS

All patients received 14 days of cytokine therapy in three groups: four patients were treated with GMCSF (5 micrograms/kg/d SQ), eight patients were treated with GMCSF (5 micrograms/kg/d SQ) and monoclonal antibody (MAbR24) and six patients were treated with MCSF (80 micrograms/kg/d IVCI) and MAbR24. Dynamic FDG-PET imaging was performed over the lower thoracic or upper lumbar spine at four time points in each patient.

RESULTS

Baseline glucose metabolic rates in the bone marrow of these three groups of patients were similar (5.2 +/- 0.7, 4.4 +/- 0.8 and 4.8 +/- 1.2 micrograms/min/g as mean value and standard deviations, respectively). In both GMCSF and GMCSF + R24 groups, rapid increases in bone marrow glucose metabolic rates were observed during therapy. After GMCSF was stopped, bone marrow glucose metabolic rates rapidly decreased in both groups. The glucose metabolic response in these two groups was not significantly different by pooled t-statistics (p = 0.105). In the MCSF+R24 group, the increase of glucose metabolic rate on Days 3 and 10 was 35% and 31% above baseline on the average, but was not significant.

CONCLUSION

The results support the use of parametric FDG-PET imaging for noninvasive quantitation of bone marrow glucose metabolic changes to hematopoietic cytokines in vivo.

Spontaneous resolution of fetal mediastinal cystic hygroma

We present a case of prenatally diagnosed mediastinal cystic hygroma with spontaneous resolution. To our knowledge, this is only the second case report of mediastinal cystic hygroma diagnosed prenatally, and the first one with spontaneous resolution perinatally. Our case shows that, in the absence of hydrops fetalis, mediastinal cystic hygroma in a fetus with normal karyotype can be associated with a normal outcome. Therefore we recommend fetal karyotyping, a careful search for other anomalies and close sonographic follow-up in such cases.

Actinobacillus actinomycetemcomitans pneumonia with chest wall and subphrenic abscess

A 14-year-old girl had progressive dyspnea and right lower chest pain for about 1 1/2 months and a weight loss of 3 kg in 2 months. Chest X-ray revealed right pleural effusion and a round infiltration over the right lower chest, initially suspected to be malignant. Image study revealed consolidation in the right middle and lower lobes with abscess-like lesions around the right lower pleura and transdiaphrenic involvement to the subphrenic region. The lesion had also invaded the intercostal muscle. The pleural abscess was obtained by fiberoptic thoracoscopy, and culture of the pus grew typical colonies of Actinobacillus actinomycetemcomitans. After the causative microorganism had been identified, cefoxitin was given for 2 weeks followed by oral amoxicillin (250 mg/6 h) for a total period of 3 months. Follow-up chest X-ray revealed resolution of the lung lesions and the patient recovered gradually without any sequelae.

Measurement of organ volume by single photon emission computed tomography

The aim of this study was to develop a new algorithm for volume determination by single photon emission computed tomography (SPECT). Different algorithms were evaluated through phantom studies. The results show that the algorithm combining moment-preserving bilevel thresholding and best-fit Laplacian second derivative edge detection can provide the most accurate measurement of volume. Besides, this method can be utilized in different SPECT systems with no need for further phantom studies. In patient studies, the results of liver volume calculation have indicated that this is a useful technique in clinical medicine.

Seroepidemiology of hepatitis A virus infection in southern Taiwan

Hepatitis A virus infection was common in Taiwan. Most of the Taiwan data on the prevalence of Hepatitis A virus antibody (anti-HAV), however have derived from the Taipei area and few reports are available on the age-specific prevalence in other parts of Taiwan. Sera of 738 healthy inhabitants in Tainan District, a rural southern Taiwan, were collected from January to December, 1992, and screened the anti-HAV IgG by radioimmunoassay. The prevalence rate of anti-HAV among infants was 64.6%, which decreased to 3.3% in preschool and school-age children up to 12 years old. The prevalence rate of anti-HAV antibodies was over 92% in adult subjects beyond 30 years of age, and 82.4% among 34 pregnant women. Compared to the data obtained from the children living in Taipei City, our results showed that the prevalence rate of anti-HAV in age group 1 to 10 years in Tainan area was higher than Taipei City (2.3-3.7% vs. 0-0.5%, 0.03 < P < 0.09). The data also indicated that the age of primary infection in children has extended to an older age group. The rarity of HAV infection in Taiwan has created a large growing population of susceptible young adults. Mass vaccination for this population should be considered in the preventive program of public health.

Musculoskeletal changes in children prenatally exposed to polychlorinated biphenyls and related compounds (Yu-Cheng children)

Fifty-five Yu-Cheng (oil-disease) children born between 1978 and 1985 to mothers who ate PCB-contaminated rice oil in 1978-1979 were studied and compared to age- and sex-matched control subjects in 1991. The children's growth profiles, bone mineral density and soft tissue composition, joint laxity, and serum parathyroid hormone, vitamin D, calcium, alkaline phosphatase, and phosphate were compared. The Yu-Cheng children were 3.1 cm (p < .05) smaller and had less total lean mass and soft tissue mass as compared to the matched control subjects. All other parameters studied were similar in both groups. The shorter height and decreased total lean mass and soft tissue content were only seen in the Yu-Cheng children who were the first born after the ingestion, but not in subsequent children. This was most likely due to decreased body burdens of the PCBs and related contaminants over time in the mothers.

[One year follow-up study of the recovery of adrenal insufficiency induced by formulated herb drugs]

Previous studies have found that taking formulated herb drugs may reduce the serum cortisol level which may result in an adrenal insufficiency. We suspect that this effect is induced by corticosteroids artificially mixed in formulated herb drugs. The objectives of this study were to determine the time course of serum cortisol and plasma ACTH (adrenocorticotropic hormone) levels, and whether pituitary-adrenal function recovers after quitting formulated herb drugs for a period of one year. Forty eight subjects with an initial serum cortisol level smaller than 10.7 micrograms/dL due to the intake of formulated herb drugs were recruited. They were tested for serum cortisol and plasma ACTH levels at 08:00 6, 9 and 12 months after quitting formulated herb drugs, respectively. The diagnosis of adrenal insufficiency was confirmed by an ACTH test at 9 months and 12 months after quitting the formulated herb drugs. The follow-up rates ranged from 63% to 71%. The 08:00 serum cortisol levels at the initial test, 6 months, 9 months, and 12 months were 4.4 +/- 0.5 micrograms/dL, 6.6 +/- 0.8 micrograms/dL, 6.6 +/- 0.7 micrograms/dL, 6.2 +/- 0.8 micrograms/dL, respectively, (interpersonal p = 0.0001, intrapersonal p = 0.0004, repeated measures ANOVA test.) The 08:00 plasma ACTH levels at the initial test, 6 months, 9 months and 12 months were 33.8 +/- 6.4 pg/mL, 67.6 +/- 16.8 pg/mL, 21.0 +/- 3.2 pg/mL, 16.3 +/- 2.2 pg/mL, respectively (interpersonal P = 0.0001, intrapersonal P = 0.0003, repeated measures ANOVA test.) The statistical significance was the same after logarithmic transformation of the ACTH levels.(ABSTRACT TRUNCATED AT 250 WORDS)