Apolipoprotein (a) phenotypes in cardio-cerebrovascular diseases

Apolipoprotein (a) [Lp(a)] phenotypes of 69 myocardial infarction survivor and 56 stroke patients were reported and compared to those of 190 healthy Chinese. The results revealed that the distributions of apo(a) phenotype frequency in patients with cardio-cerebrovascular disease (CCVD) were different from those of controls. The frequency of the phenotypes S1 and S2 were remarkably higher in patients than in controls within the same single-band apo(a) phenotype. Moreover, the Lp (a) serum concentrations in CCVD patients were significantly higher than in controls within the same single-band apo (a) phenotype. The apo (a) phenotype analysis of two pedigrees were shown as a typical autosomal dominant inheritance.

[Total intravenous anesthesia with O2 mask in transthoracic endoscopic sympathectomy for palmar hyperhidrosis]

Using non-invasive monitors (such as blood pressure, O2 saturation, end-tidal CO2 pressure monitors and electrocardiograms), the application of total intravenous anesthesia with O2 mask in transthoracic endoscopic sympathectomy was evaluated. A total of 198 palmar hyperhidrosis patients were studied. In the study, the durations of surgery were 5-15 min (mean 8 min) with anesthesia duration of 8-20 min (mean 12 min), respectively. The cardiovascular system was quite stable during operation, with systolic blood pressures of 90-165 mmHg (mean 132 mmHg), diastolic blood pressures of 50-106 mmHg (mean 92 mmHg) and heart rates of 56-130 beats/min (mean 104 beats/min). The respiratory function was maintained within a safety range with O2 saturation of 95-100% (mean 99%) and end-tidal CO2 pressure of 32-40 mmHg (mean 36 mmHg). After surgery, the major discomfort was chest pain (132/198), but this could be improved with intravenous analgesics. Patients' consciousness returned within 1-3 min. After ensuring their general condition was stable, patients were discharged within 24 hr. Preliminary study showed that total intravenous anesthesia plus muscle relaxant, with O2 mask and assisted ventilation, could serve as a safe and simple anesthesia for palmar hyperhidrosis patients who received transthoracic endoscopic sympathectomy.

Cyclical strain increases endothelin-1 secretion and gene expression in human endothelial cells

We examined the effects of cyclical strain on endothelin-1 (Et-1) secretion and Et-1 mRNA levels in human umbilical vein endothelial cells. Cultured endothelial cells grown on a flexible membrane base were deformed by vacuum to 20% of maximum strain, at 60 cycles/min, for various time periods. The rate of Et-1 release from strain- treated cells and their Et-1 mRNA levels were measured. Cells subjected to strain increased their Et-1 secretion into the culture medium from 0.17 ng/hr/10(6) cells to 0.44 ng/hr/10(6) cells. Concomitantly, the Et-1 mRNA levels in strained cells increased 1.4-, 2.1- or 2.6- fold (vs control unstrained cells) after 0.25, 0.5 or 6 hours of strain, respectively. Cells exposed to longer periods of strain (> 6 hrs) did not further increase their mRNA expression. Pretreatment with calphostin C, a specific inhibitor of protein kinase C, before straining completely abolished Et-1 mRNA expression. These results indicate that mechanical strain can modulate the secretion of Et-1 from endothelial cells by increasing Et-1 mRNA levels via the protein kinase C pathway. Elevation of Et-1 secretion and gene expression in endothelial cells under physiological strain might influence normal or pathological states of the vasculature and cardiac growth.

[Effects of stimulating lateral hypothalamic area and ventromedial nucleus of hypothalamus on cerebellar cortical neuronal activity in the cat]

In pentobarbital anaesthetized cat, stimulating lateral hypothalamic area (LHA) and ventromedial nucleus (VMN) of the hypothalamus could elicit inhibitory, excitatory or inhibitory-excitatory responses of cerebellar Purkinje cells (PC) and non-Purkinje cells (NPC) in the loubles VI and VII. The majority of responses are inhibitory (80.4%) usually with a latency of 10-20 ms, or occassionaly as long as 90 ms. Usually stimulation of LHA was more effective and NPC was more responsive. The aforementioned inhibitory response could be blocked by iv. chlorpheniramine. The possible role of the hypothalamo-cerebellar activity was discussed.

Increased lipoprotein (a) as an independent risk factor for cardiovascular and cerebrovascular diseases

We quantified serum lipoprotein(a) [Lp(a)] in 1266 healthy persons and established the reference value of Lp(a) in groups of age and sex. The Lp(a) in myocardial infarction (MI) survivors, stroke and primary hypertension patients were determined in comparison with that of age-matched normal controls. Moreover, cholesterol, triglyceride, HDL-cholesterol, apo Al and apo B were measured. The Lp(a) concentrations were not correlated with other lipids in normal controls and patients. Our results suggest that increased Lp(a) is an independent risk factor for MI and stroke patients. The total detective rate of abnormal lipids in MI and stroke patients was as high as 50% and 53.8% (Lp(a) excluded) as well as 65.7% and 64.9% (Lp(a) included) respectively.

Oxidative damage to DNA: levels of thymine glycol and thymidine glycol in neoplastic human urines

We have measured the levels of thymine glycol (TG) and thymidine glycol (dTG) in human urine, using an HPLC method. The results show that all 30 specimens examined (including 10 non-neoplastic and 20 neoplastic human urines) contained significant amounts of TG and dTG, average levels (mean +/- SEM) were 0.376 +/- 0.026 and 0.138 +/- 0.009 nmol/kg body weight/day respectively. The average levels of TG and dTG were 0.435 +/- 0.038 and 0.164 +/- 0.017 nmol/kg body weight/day in 10 healthy human urine specimens and 0.347 +/- 0.035 and 0.125 +/- 0.010 nmol/kg body weight/day in 20 neoplastic human urine specimens respectively. No significant differences were found between female and male as well as between the non-neoplastic and neoplastic human urine specimens. There were also wide interindividual variations, which were not age-dependent.

Molecular cloning of three isoforms of the L-type voltage-dependent calcium channel beta subunit from normal human heart

We have cloned and sequenced cDNAs for three isoforms of the L-type voltage-dependent calcium channel beta subunit isolated from a normal human heart cDNA library. One of these subunits, designated beta a, hybridized with a 3.4-kb message, and the other two, designated beta b and beta c, hybridized with a message of approximately 1.9 kb. The presence of both of these latter two messages in human heart was confirmed by polymerase chain reaction methodology. Considering the differences between beta a and beta b/beta c, we find it likely that these messages may be encoded by two different gene sequences, beta a and beta b/beta c, and that the beta b/beta c sequence can be alternatively spliced in the 209-260 region. The data suggest that the human heart presents a different pattern of beta subunit expression from that found in the rat and rabbit heart.

Evaluation of gastric emptying in severe, burn-injured patients

OBJECTIVE

The aim of this study was to evaluate the possible effect of a severe burn on gastric emptying by determining the absorption kinetics of orally administered acetaminophen.

DESIGN

A prospective, controlled study.

SETTING

A ten-bed burn center in a 1,300-bed university hospital.

PATIENTS

Ten adult patients suffering from second-degree burn involving > 20% of total body surface area and 20 normal, healthy volunteers who acted as controls.

INTERVENTIONS

Patients received routine treatment such as nutritional support and cimetidine. However, opiates were stopped for at least 12 hrs before the start of the study, and nonsteroidal anti-inflammatory drugs as alternatives were used. After an 8-hr fast, the subjects ingested 0.5 g acetaminophen with 200 mL of water. The plasma concentrations of acetaminophen were determined by high-performance liquid chromatography, and the absorption kinetics was estimated from determination of time to reach the maximum plasma concentration, the maximum plasma concentration, and the area under the plasma concentration-time curve.

MEASUREMENTS AND MAIN RESULTS

The mean time for reaching the maximum plasma concentration was 33 +/- 24 (SD) mins in patients and 39 +/- 24 mins in the healthy volunteers. The mean area under the plasma concentration-time curve from time 0 to 120 mins and the mean maximum plasma concentration were 556 +/- 190 micrograms/mL/min and 9.5 +/- 3.5 micrograms/mL in patients, and 539 +/- 131 micrograms/mL/min and 7.8 +/- 2.8 micrograms/mL in volunteers, respectively. There was no statistical difference between groups in the time to reach the maximum plasma concentration, the area under the plasma concentration-time curve from time 0 to 120 mins, and the maximum plasma concentration. The time for reaching the maximum plasma concentration was not correlated with the severity of the burn (% area of burn) and the duration of healing (days) after burn.

CONCLUSIONS

We conclude that severe burn injury does not affect the kinetics of gastric emptying, and that 200 mL of water ingested 2 hrs before anesthesia is quite safe in severely burned patients. Also, the absorption kinetics of acetaminophen was not altered by burn injury.

Clinical and sonographic assessment of liver size in normal Chinese neonates

Liver size and midclavicular line were measured by clinical and sonographic methods in 145 normal Chinese neonates with gestational ages of 34-42 weeks. The liver span, measured by clinical methods with percussion and percussion/palpation methods, correlated well with that measured by sonography (r = 0.73 and r = 0.76, respectively) for the entire sample. The liver spans (mean +/- SD) obtained by sonography were 4.24 +/- 0.63 cm and 4.58 +/- 0.56 cm in the preterm and term neonates, respectively. The liver span (sonography) and the distance of the liver edge below the right costal margin were weakly related in the term neonates (r = 0.36), but unrelated in the preterm neonates. We conclude that the liver span is a better estimate of liver size than the distance below the right coastal margin in normal neonates. We also found that the mean liver span is approximately 1 cm smaller in Chinese neonates than in Western neonates.

[On the concept of bencao]

Being the typical traditional Chinese pharmacy closely related with medicine, Bencao is a knowledge of extensive contents including what is presently called Chinese materia medica. It also has a systematic theory and valuable experience of practice. Today Bencao is still of practical significance for medical and health work in our country.

[Effect of stimulation of gigantocellulars reticular nucleus on the spontaneous and evoked activities of cerebellar Purkinje cells in the rat]

In anesthetized and paralyzed rats, the effect of stimulation of Gigantocellulars Reticular Nucleus (Gi) on spontaneous and evoked simple spike discharges of cerebellar Purkinje cells (PCs) was examined. The result were as follows: (1) Stimulation of Gi elicited either inhibitory or excitatory effect on spontaneous simple spikes of PCs with latency less than 20 ms, being inhibitory in the most cases. The inhibitory responses lasted for 40-100 ms, while the excitatory ones were sometimes longer than 200 ms; (2) Injection of 5-HT2 receptor antagonist methysergide could reversibly attenuate or block the inhibitory effect of Gi stimulation on spontaneous simple spike discharges of PCs; (3) The evoked simple spike responses of PCs elicited by stimulating the contralateral cerebral sensorimotor cortex could be markedly suppressed or potentiated by the conditioning Gi stimulation. The results demonstrated that Gi-cerebellar pathways exists, with some fibers being serotonergic. Gi-cerebellar afferent fibers may have certain modulatory effects on PCs through synaptic and/or non-classical chemical synaptic transmission. The Gi-cerebellar afferent fiber projection may play important roles in some cerebellar functions, such as regulating myotonia and posture.

[A preliminary study of immuno-electron microscopy of endothelium in cardiovascular system]

The immunocytochemical localizations of the von Willebrand factor (vWF), endothelin-1 (ET-1) and the beta 2-adrenergic receptor (beta 2R) in cultured human umbilical vein endothelial cells (HUVEC) after thrombin treatment have been demonstrated. Competitive ELISA analysis of these treated cells indicate an increase in vWF deposition on the subendothelial matrix (1.5 folds vs control) and vWF release (3.8 folds vs control) in the culture medium. The vWF-peroxidase, immunogold labeling and in situ hybridization of ET-1 were demonstrated on HUVEC. Double labelling with different sized gold particles for the ET-1 and beta 2R locations were performed on the hearts of young adult WEY, SHR, and SHRsp rats. The results were as follows. (1) Positive vWF deposits were detected on the extracellular matrix, Weibel-Palade bodies and secreting vesicles in the cytoplasm. It is suggested that both the constituted and regulated pathways are involved in the secretion of vWF stimulated by thrombin. (2) The gene expression of ET-1 was detected by light microscopic in situ hybridization in HUVEC. (3) ET-1 was detected by immunoelectron microscopy in the lysosome, cell surface, and extracellular matrix, suggesting that lysosome possibly plays an important role in the processing of ET-1 in HUVEC. (4) The presence of both ET-1 and beta 2R have been successfully detected in adult heart tissues and the endothelial cells of rats. These observations suggest the functional importance of ET-1 and beta 2R.

Hepatic cavernous hemangioma. CT findings and pathological basis

CT findings in 113 cases of hepatic hemangioma confirmed pathologically including 52 resected specimens and 8 autopsies were studied in correlation with the typical CT scan of 506 cases of the same disease. Mottling enhancement in the surrounding hepatic parenchyma of hemangioma which never appeared in other kinds of tumor was considered as a pathognomonic sign for diagnosis. It was correlated with the presence of dilated vascular spaces or sinusoids communicating with the tumor itself in the surrounding tissue. The thick wall and thin wall types of hemangioma were discussed.

Immunomodulating effects of the hydrolysis products of formosanin C and beta-ecdysone from Paris formosana Hayata

Formosanin C (PF-3, I), a diosgenin glycoside with four sugars isolated from Paris formosana Hayata as main constituent, significantly showed immunomodulating effects on the proliferative response of mouse lymphocytes to concanavalin A (Con A). The partialy hydrolysis products of formosanin C, dioscin (II) and prosapogenin A of dioscin (III), also increased 3H-thymidine incorporation of Con A-stimulated lymphocytes maximally at 0.01 micrograms/ml, whereas formosanin C did so at 0.0001 micrograms/ml. However, trillin (IV) and diosgenin (V) obtained from the partial hydrolysis of formosanin C had no effects on these immune responses. Evidently, the immunomodulating activities increased in the order of increasing polarity. Probably the solubility in water was a factor. This demonstrated that the sugar moiety in the structure of formosanin C (I) displays a very important pattern for the effect on the proliferative response of mouse lymphocytes to Con A. On the other hand, these hydrolysis products at higher concentrations of 1 and 10 micrograms/ml reduced the cytotoxic effects on spleen cells as compared with formosanin C. The other constituent, beta-ecdysone (VI) isolated from the stems of Paris formosana Hayata also increased 3H-thymidine incorporation of Con A-stimulated splenocytes. At the concentration of 0.001 micrograms/ml, the stimulation index of beta-ecdysone (2) is higher than that of formosanin C (1.65), and at the concentration of 100 micrograms/ml, beta-ecdysone had no cytotoxicity for normal spleen cells whereas formosanin C at the lower concentration of 10 micrograms/ml showed cytotoxicity. Based on this study, beta-ecdysone (VI) is therefore a better immunomodulator than formosanin C.

Template-directed design of a DNA-DNA cross-linker based upon a bis-tomaymycin-duplex adduct

A template-directed approach to the design of a DNA-DNA interstrand cross-linker based upon the structure of a bis-tomaymycin-duplex adduct has been carried out. Tomaymycin is a member of the pyrrolo[1,4]benzodiazepines antitumor antibiotics. In a previous study (F.L. Boyd et al., Biochemistry 1990, 29, 2387-2403), we have shown that two tomaymycin molecules can be covalently bound to a 12-mer duplex molecule, where the drug molecules are on opposite strands six base-pairs apart, and the stereochemistry at the drug bonding site, and orientation in the minor groove, was defined by high-field NMR. This bis-tomaymycin 12-mer duplex adduct maintains the self-complementarity of the duplex and a B-type structure. In the present study we have shown using high-field NMR that this same 12-mer sequence can be truncated by two base pairs so that the two tomaymycin-modified guanines are now only four base-pairs apart, the two species of tomaymycin molecules are still bound with the same stereochemistry and orientation, and the 10-mer duplex adduct maintains its self-complementarity. In a second 10-mer duplex we have shown that changing the bonding sequence from 5'CGA to 5'AGC does not significantly affect the structure of the bis-tomaymycin-duplex adduct. However, when the sequence is rearranged so that the drugs point in a tail-to-tail orientation rather than in the previous head-to-head configuration, there are more than one species of tomaymycin bound to DNA, and, as a consequence, the bis-tomaymycin 10-mer duplex adduct loses its self-complementarity. Last, we have used the 10-mer duplex containing the 5'CGA sequence, in which the tomaymycin molecules are oriented head to head, to design an interstrand cross-linking species in which the two drug molecules are linked together with a flexible linker molecule.

Characterization of a human cervical carcinoma-associated antigen by lectin binding and immuno-electron microscopy

The specific binding and nature of the epitope recognized by monoclonal antibody (Mab) 1H10, which binds an antigen expressed on human cervical tumors, was characterized by enzyme digestion, lectin competition assay and immuno-electron microscopy. Membrane homogenates of CaSki cervical carcinoma cells were digested with various enzymes, then analysed by SDS-PAGE and immunoblotting. Cells grown on coverslips were treated with various enzymes and in situ binding of Mab 1H10 to cells was analysed by electron microscopy. The ability of lectin-conjugates to block Mab 1H10 binding to CaSki cells was also examined. Treatment of samples with sodium periodate abrogated antigen recognition by Mab 1H10. Neuraminidase and hyaluronidase digestion decreased but did not eliminate Mab 1H10 binding to cells in situ. Chondroitinase ABC digestion, in contrast, removed Mab 1H10 binding sites both in vitro and in situ. Trypsin and chymotrypsin digestion of cell membrane homogenates decreased the molecular weight of the Mab 1H10 antigen but did not decrease the binding intensity. Wheat germ agglutinin (WGA) strongly bound to CaSki cells and partially blocked Mab 1H10 binding, indicating that the antigen contains N-acetyl-galactosamine residues at or near the epitope recognized by Mab 1H10. Ricinus communis agglutinin (RCA) exhibited a similar binding pattern to WGA. However, concanavalin A bound only weakly to CaSki cells and was ineffective at blocking Mab 1H10 binding. The tumor-associated antigen recognized by Mab 1H10 is concluded to be a chondroitin sulphate glycoprotein or proteoglycan rather than a mucopolysaccharide or lipoprotein.

Immunomodulators from Paris formosana Hayata

Eight glycosides PF-1 to PF-8 were isolated from the leaves and stems of Paris formosana Hayata (Liliaceae), of which PF-3 (III) was the main compound. It was found that PF-1 to PF-3 (I-III) caused proliferative responses of mouse lymphocytes to concanavalin A and augmentation of mouse granulocyte/macrophage colony forming cells in mouse fibroblast cell L929 conditioned medium. PF-4(IV) and PF-8 showed significant immunomodulatory effects with very low toxicity: they not only caused the same immune responses as PF-1, 2 & 3 but also enhanced the proliferative response of human peripheral whole blood to phytohemagglutinin. PF-5 (V) also increased 3H-thymidine incorporation in ConA-stimulated lymphocytes and in PHA-stimulated human peripheral whole blood, and enhanced the proliferative response of granulocyte/macrophage colony stimulating activity. PF-6(VI) and PF-7(VII) augmented 3H-thymidine incorporation in granulocyte/macrophage colony-forming cells and mitogenic response of PHA-stimulated human peripheral whole blood cells from healthy adults. However, PF-1, 2 and 3 showed hemolytic action, while PF-4 to PF-8 had no hemolytic action at all. On the other hand, the hemolytic action of PF-3 derivatives was reduced as compared with PF-3 but their immune responses did not equal those of PF-3, only showing granulocyte/macrophage colony stimulating activity.

Mutually exclusive exon splicing of the cardiac calcium channel alpha 1 subunit gene generates developmentally regulated isoforms in the rat heart

Several clones were isolated from a rat genomic library in order to further characterize a region of variability within the third membrane-spanning region of the fourth motif (IVS3) of the L-type voltage-dependent calcium channel. We report here that this diversity arises from alternative splicing of a primary transcript containing a single pair of adjacent exons each encoding a unique sequence for the IVS3 region. Definitive proof of a mutually exclusive splicing mechanism was obtained by genomic mapping of flanking upstream and downstream exons and by extensive sequence analysis of the relevant exon/intron boundaries. S1 nuclease protection experiments revealed that both variant forms of the IVS3 were equally expressed in newborn and fetal rat heart, whereas only a single isoform predominated in adult rat heart. The results demonstrate the existence of an important developmentally regulated switch mediated by alternatively spliced exons in cardiac tissue at a time when major changes in excitation occur.

Internalization of CD4 molecules in human T-cells demonstrated by immuno-electron microscopy

Internalization of CD4 molecules on human CD4-enriched T-cells was demonstrated by immunocytochemical electron microscopy. CD4+ T-cell subclones were obtained from normal human peripheral blood, followed by one-way MLC screening and co-culturing with IL-2. Fixed and non-fixed T-cell samples were indirectly immunolabeled with mouse anti-human CD4 monoclonal antibody and goat anti-mouse IgG conjugated with peroxidase. Unfixed T-cells were immunolabeled at 4 degrees C and then re-incubated for 5-45 min at 37 degrees C. The selected CD4+ T-cell subclones showed strong CD4 binding on the cell surface after IL-2 incubation. However, fresh T-cells, monocytes, bone marrow cells and CD8+ T-cells all stained negative for CD4. The distribution of CD4 molecules on the fixed cell surface showed a homogeneous pattern. Capping and internalization of CD4-antibody-peroxidase complexes from the cell surfaces were observed follow a pathway of receptor-mediated endocytosis in unfixed T cells. Endocytotic vesicles, vacuoles of diverse sizes and shapes near the cell membrane or deep in the cell center were found to contain CD4 molecules. Negatively stained Golgi saccules were observed up to 45 min after re-incubation. These results suggest that increased CD4 molecules can be induced on the surface of normal human T-cells in vitro. Internalization and accumulation of CD4 molecules occurred in CD4-enriched T-cells with IL-2 pretreatment.

[Stimulation of the dorsal raphe nucleus induced depressive effect on cerebellar Purkinje cell responses to mossy and climbing fiber afferent inputs in rat]

In anaesthetized and paralyzed rats, the effect of dorsal raphe (DR) conditioning stimulation on cerebellar Purkinje cell (PC) responses to mossy fiber and climbing fiber inputs were examined. The main results are as follows: (1) Stimulation of cerebral sensorimotor cortex elicits widespread activation of mossy and climbing fiber inputs to PCs in contralateral VI and VII lobules of the cerebellum and generates two kinds of evoked responses, i.e. the simple spike (SS) and the complex spike (CS) responses with respectively a latency 8-25 and 12-30 ms. (2) These PC responses could be markedly suppressed by stimulation of DR at intensities which by themselves were subthreshold for directly affecting PC's spontaneous SS and CS activities. (3) This DR-induced depressive effects on evoked PC's SS and CS excitations could be attenuated or blocked by systemic administration of 5-HT receptor blocker methysergide. These results demonstrate that serotonergic fiber input from DR can suppress the efficacy of mossy and climbing fiber synaptic action on PC, or decrease the responsiveness of PC itself to afferent synaptic action. The findings of this study also suggest that the raphe-cerebellar serotonergic fiber afferent system may be involved in some of the important neuronal processing in the cerebellum.

Determination of buprenorphine by high-performance liquid chromatography with fluorescence detection: application to human and rabbit pharmacokinetic studies

A rapid, sensitive, precise and accurate high-performance liquid chromatographic assay with fluorescence detection was developed for the determination of buprenorphine in human, rabbit, pig and dog plasma. It is comprised of only a one-step extraction procedure with hexane-isoamyl alcohol at pH 9.25 and reversed-phase chromatography on a muPorasil column. The recoveries of buprenorphine and nalbuphine (internal standard) were greater than 90%. Calibration graphs were linear over the concentration range 3-300 ng/ml with a coefficient of variation, both within-day and between-day, of less than 9% at any level. The limit of detection was 1.0 ng/ml of plasma based on a signal-to-noise ratio of 3. Eight other clinically used narcotics were investigated to check for potential interferences and their analytical conditions. The possible decomposed compounds of buprenorphine were also checked for the specificity of this assay. The method has been successfully applied to the stability and pharmacokinetic studies of buprenorphine. Buprenorphine in plasma did not decompose significantly at -20 degrees C for four weeks. Pharmacokinetic application in six rabbits and a surgical patient revealed that buprenorphine followed a linear three-compartment model with two distribution phases. The two distribution and elimination half-lives and the clearance of buprenorphine were 1.32, 24.8 and 230 min and 224 ml/min in human plasma, and 0.94, 12.5 and 232 min and 30 ml/min in rabbit plasma.

Molecular cloning of multiple subtypes of a novel rat brain isoform of the alpha 1 subunit of the voltage-dependent calcium channel

Several cDNAs encoding an isoform of the alpha 1 subunit of the voltage-dependent calcium channel were isolated from rat brain cDNA libraries. The complete nucleotide sequence of 6975 bp encodes a protein of 1634 amino acids, which corresponds to an Mr of 186,968. The protein exhibits 71% and 76% homology to skeletal and cardiac alpha 1 subunits, respectively. When compared with skeletal and cardiac alpha 1 isoforms, the rat brain protein is intermediate in size at the amino terminus and shorter at the carboxyl terminus. Multiple subtypes of this alpha 1 isoform cDNA were characterized. These are indicative of alternative splicing of a primary transcript and encode three variants between motif I and motif II and two within the S3 region of motif IV. Thus, multiple isoforms of this rat brain alpha 1 subunit are possible.

Abnormal thyroid hormone levels in critical nonthyroidal illness

Low levels of thyroid hormone in the absence of clinical hypothyroidism often happen to patients with critical non-thyroidal illnesses (NTI). Low thyroid hormone concentrations in serum do not necessarily mean hypofunction of the thyroid gland; rather it is a helpful adaptation of the human body to the underlying diseases. We collected 133 hospitalized cases of critical NTI and analyzed the incidence of this phenomenon. Fifty-three per cent of the patients had T3 level lower than 60 ng/dl (normal:85-165 ng/dl) and 60% had T4 level lower than 6 ug/dl (normal:6-12 ug/dl). The lowest levels were observed in patients who had sepsis, were aged over 70 or died in this admission. Free T4 and TSH levels were within normal range in most cases. There is a strong negative correlation between the prognosis and the level of T4 in these patients. Those patients with markedly low levels of T3 and T4 should be treated more sophisticatedly.

Serotonin (5-HT1c) receptors in pig choroid plexus

It is very important to find suitable reaction conditions to attain a high specific binding (specific/total binding) in the receptor binding study. Membrane homogenates of pig choroid plexus are known to have exclusively serotonin (5-hydroxytryptamine, 5-HT) receptor of the subtype 5-HT1c. In this study, we used the membrane preparation of pig choroid plexus tissue and the specific binding of [3H]5-HT was 72-84% to serotonin receptor subtype 5-HT1c, as defined by the inhibition of 1 uM 5-HT, when a radioligand concentration of 0.5 nM of [3H]5-HT was used in the assay. Analysis of the properties of specific [3H]5-HT binding in pig choroid plexus tissue membrane preparation revealed linear Scatchard plots. In Tris-HCl buffer without CaCl2, pargyline or ascorbic acid, high average of affinity dissociation constant (Kd) of 1.3 +/- 0.2 nM (SEM, n = 4) and also a high average of receptor density (Bmax) of 284 +/- 12 fmol/mg of protein were found. Pig choroid plexus proves to be a good material for 5-HT1c receptor binding study.

Identification of two maturation-related, wheat-germ-lectin-binding proteins on the surface of mouse sperm

Epididymal maturation is essential for mammalian sperm to develop fertility. Wheat germ agglutinin (WGA), a lectin which specifically recognizes N-acetyl-glucosamine and sialic acid, was used to investigate membrane characteristics of epididymal sperm in the mouse. Histochemical and cytochemical localization revealed that WGA-binding sites were increased as sperm became mature. The binding sites were mainly localized in the plasma membrane of the anterior acrosome and tails. On Western blots of NP-40 extracts, two WGA-binding glycoproteins, GP-49 and GP-83, were identified on the sperm recovered from both corpus and cauda epididymidis. GP-83 was removed from the sperm surface by centrifugation and resuspension in phosphate-buffered saline (PBS) three times. GP-49 was resistant to centrifuging at 400 g for 5 min up to seven times and the treatment with 1M NaCl in PBS. These observations suggest that GP-49 is very likely an intrinsic membrane protein of the sperm, whereas GP-83 is an extrinsic protein.