Distributed-feedback optical parametric oscillation by use of a photorefractive grating in periodically poled lithium niobate

We report a demonstration of distributed-feedback (DFB) optical parametric oscillation (OPO) by writing photorefractive gratings in periodically poled lithium niobate (PPLN). The photorefractive DFB structures were fabricated by illumination of PPLN with UV light through a photomask and by writing of PPLN with UV-light gated interfering laser beams at 532 nm. Evidence of OPO was observed from the spectral narrowing at the 1438.8- and the 619.3-nm signal wavelengths from 1064- and 532-nm-pumped PPLN crystals with the DFB grating periods phase matched to the 4084.5- and 3774-nm idler wavelengths, respectively.

Oscillatory interaction between human motor cortex and trunk muscles during isometric contraction

We investigated oscillatory interaction between magnetoencephalographic signals of the human motor cortex and surface electromyogram from the paraspinal (PS) and abdominal (ABD) muscles. The results were compared with data obtained during contraction of the first dorsal interosseus (FDI) and tibialis anterior (TA) muscles. Significant coherence at 15-35 Hz was observed for both PS and ABD muscles in all subjects but the coherence was weak compared with that for FDI and TA. The cortical sources for both the PS and the ABD coherences were located in the motor cortex between the source areas for the FDI and TA coherences, thereby agreeing with the classical trunk area of the motor homunculus previously determined by invasive studies. The sources were strictly contralateral for PS but bilateral for ABD contractions. Our results indicate that during isometric contractions descending motor commands are modulated by cortical oscillations for both limb and trunk muscles, although the modulation is weaker and may be bilateral for trunk muscles.

Impact of parent death and an intervention on the adjustment of adolescents whose parents have HIV/AIDS

The impact of parental death and the efficacy of a coping-skills intervention were examined on the adjustment of 211 adolescent children of parents with HIV/AIDS (PWH) over a 2-year period. During the follow-up period, 35% of the PWH died. Using longitudinal structural equation model, controlling for prior measures of adjustment at baseline, the authors found that children of deceased PWH reported significantly more emotional distress and problem behaviors 2 years later. Youth randomized with their parent to a coping-skills intervention reported significantly fewer problem behaviors and sexual partners 2 years later. Also, adolescents were better-adjusted 2 years later when their parents had reported less emotional distress and less severe physical health symptoms at baseline. Female adolescents reported more emotional distress at baseline and at 2 years than males; male adolescents reported more problem behaviors at baseline than the females.

Lateralizing value of early head turning and ictal dystonia in temporal lobe seizures: a video-EEG study

To investigate early head turning, we retrospectively studied videotapes of 262 seizures from 82 patients who were seizure free after temporal lobectomy. Early head movements were arbitrarily classified into non-tonic turning, tonic turning, and absence of turning. Among the 222 seizures which showed early head turning, 168 (75.7%) had non-tonic turning and 54 (24.3%) had tonic turning. The direction of the first head turning was ipsilateral to the epileptogenic foci in 132 (78.6%) seizures with non-tonic turning and in 35 (64.8%) seizures showing tonic head turning. The proportion of seizures with turning towards the ipsilateral side in the presence of tonic and non-tonic head turning were significantly different (P= 0.04). Seventy-four seizures (28.2%) evolved to secondary generalization, more frequently found in seizures with early head turning (P= 0.0015) and especially those showing tonic turning (P< 0.0001). The direction of head turning immediately preceding secondary generalization was contralateral to the lesion side in 53 seizures (82.8%). Dystonic upper limb posturing occurred in 86 seizures (32.8%), exclusively contralateral to the seizure focus, whereas 65 (75.6%) were associated with initial head turning ipsilateral to the focus. In summary, temporal lobe seizures with tonic head turning tends to secondarily generalize and the direction of head turning before secondarily generalized was contralateral to the seizure foci. Earlier in the seizures the direction of non-tonic head turning tends to be towards the epileptogenic hemisphere. In addition, dystonic posturing of the extremities is a significant lateralizing sign to the contralateral hemisphere in temporal lobe seizures.

Reflections on sterol sidechain cleavage process catalyzed by cytochrome P450(scc)

The essay examines the evidence upon which the presently accepted version of the mechanism of the cytochrome P450(scc)-catalyzed-cleavage of the sidechain of cholesterol is based. This analysis indicates that the generally held view of the process (two consecutive hydroxylations, followed by cleavage of the resulting glycol) most likely does not describe the true mechanism. The available evidence can not be used to support this traditional notion. Two alternative hypotheses are proposed.

Novel mutations of CYP3A4 in Chinese

Human cytochrome P450 3A4 is a major P450 enzyme in the liver and gastrointestinal tract. It plays important roles in the metabolism of a wide variety of drugs, some endogenous steroids, and harmful environmental contaminants. CYP3A4 exhibits a remarkable interindividual activity variation as high as 20-fold. To investigate whether the interindividual variation in CYP3A4 levels can be partly explained by genetic polymorphism, we analyzed DNA samples from 102 Chinese subjects by polymerase chain reaction (PCR)-single-strand conformation polymorphism analysis for novel point mutation in the CYP3A4 coding sequence and promoter region. Using PCR and directed sequencing method to establish the complete intron sequence of CYP3A4 from leukocytes, the complete genomic sequence from exon 1 through 13 of CYP3A4 was determined and published in the GenBank database (accession no. AF209389). CYP3A4-specific primers were designed accordingly. After PCR-single-strand conformation polymorphism and restriction fragment length polymorphism screening, we found three novel mutations; two are point mutations and one is insertion. The first variant allele (CYP3A4*4), an Ile118Val change, was found in 3 of 102 Chinese subjects. The next allele (CYP3A4*5), which causes a Pro218Arg amino acid change, was found in 2 of 102 subjects. We found an insertion in A(17776), designated as CYP3A4*6, which causes frame shift and an early stop codon in exon 9, in one heterozygous subject. We also investigated the CYP3A4 activity in these mutant subjects by measuring the morning spot urinary 6beta-hydroxycortisol to free cortisol ratio with the enzyme-linked immunosorbent assay method. When compared with healthy Chinese population data, the 6beta-hydroxycortisol to free cortisol ratio data suggested that these alleles (CYP3A4*4, CYP3A4*5, and CYP3A4*6) may decrease the CYP3A4 activity. Incidences of these mutations in Chinese subjects are rare. The prevalence of these point mutations in other ethnic groups and its effect on the metabolic activity of CYP3A4 remain to be further evaluated.

Resurrection of crushed magnetization and chaotic dynamics in solution NMR spectroscopy

We show experimentally and theoretically that two readily observed effects in solution nuclear magnetic resonance (NMR)-radiation damping and the dipolar field-combine to generate bizarre spin dynamics (including chaotic evolution) even with extraordinarily simple sequences. For example, seemingly insignificant residual magnetization after a crusher gradient triggers exponential regrowth of the magnetization, followed by aperiodic turbulent spin motion. The estimated Lyapunov exponent suggests the onset of spatial-temporal chaos and the existence of chaotic attractors. This effect leads to highly irreproducible experimental decays that amplify minor nonuniformities such as temperature gradients. Imaging applications and consequences for other NMR studies are discussed.

Differential effects of muscle contraction from various body parts on neuromagnetic somatosensory responses

We studied eight healthy subjects with a whole-scalp 306-channel neuromagnetometer to explore the effect of motor activity from different body parts on somatosensory responses to left median nerve stimulation. The stimuli produced clear tactile sensation without any motor movement. In the rest condition, the subject had no task. During contraction conditions, the subject had to maintain submaximal isometric contraction in masseter, left deltoid, left thenar, or left tibialis muscles. Short-latency responses from the primary somatosensory cortex did not change during contraction. Responses from both the right (contralateral) and left second somatosensory cortices (SII) were significantly enhanced during contraction of the left thenar muscles. Responses from the left SII were significantly enhanced also during contraction of the left deltoid muscles, but they were decreased during contraction of the masseter and left tibialis anterior muscles. This study implies that SII activation is modulated by motor activity and that the effect depends on the topographical proximity of the stimulated and contracted body parts.

Evaluation of pre- and postdilutional on-line hemodiafiltration adequacy by partial dialysate quantification and on-line urea monitor

On-line highflux hemodiafiltration (HDF) is a clinically interesting and effective mode of renal replacement therapy, which offers the possibility to obtain an increased removal of both small and large solutes. The fundamental role of urea kinetic monitoring to assess dialysis adequacy in conventional hemodialysis has been widely studied. Both direct measurement of the urea removed by the modified direct dialysate quantitation (mDDQ) based on partial dialysate collection (PDC) and dialysate-based urea kinetic modeling (DUKM) using urea monitor have been advocated. The validity of this assessment tool in the patients with on-line HDF remained unclear. The aims of this investigation were (1) to compare the delivered Kt/V, urea mass removal (UMR), solute removal index (SRI) and normalized protein catabolic rate (nPCR) between pre- and postdilutional high-flux HDF; (2) to verify and compare the efficiency of pre- and postdilutional HDF using DUKM with on-line dialysate urea sensor, and mDDQ with partial dialysate collection. During both mode of HDF, the paired analysis urea removed and Kt/V showed no significant difference. Using mDDQ, mean values for predilutional mode were as follows: Kt/V 1.53 +/- 0.01 UMR, 16.8 +/- 0.3 g/session; urea clearance 178 +/- 18 ml/min; SRI 75.5 +/- 7.7%; urea distribution volume (V) 28.3 +/- 1.2 liters; nPCR 1.34 +/- 0.18 g/kg/day; on the other hand, mean values for postdilutional mode were Kt/V 1.58 +/- 0.01; UMR 17.10 +/- 0.28 g/session; urea clearance 184 +/- 21 ml/min; SRI 77.2 +/- 3.5%; urea distribution volume, 27.8 +/- 1.5 liters; nPCR 1.34 +/- 0.19 g/kg/day. The mean value of urea generation rate was 5.82 +/- 1.12 mg/min during HDF. Our results showed that dialysis adequacy was achieved with both high-volume predilutional HDF and postdilutional HDF. These two modes of HDF provided similar and adequate small solute clearance. In addition, we found that on-line analysis of urea kinetics is a reliable tool for quantifying and assuring delivery of adequate dialysis.

Transient elevation in plasma prolactin level in rats with temporal lobe status epilepticus

Microinjection of kainic acid into the CA3 subfield of hippocampus in anesthetized rats elicited seizure-like hippocampal EEG activity that persisted for more than 180 minutes. There was a concomitant rise in plasma prolactin level that peaked at 15 to 20 minutes but endured less than 60 minutes. We conclude that plasma prolactin exhibited only transient elevations during experimental temporal lobe status epilepticus in rats.

Serum anti-p53 antibodies in gastric adenocarcinoma patients are associated with poor prognosis, lymph node metastasis and poorly differentiated nuclear grade

Mutation of the p53 tumour suppressor gene often leads to the accumulation of mutant p53 protein in tumour cells. Many cancer patients develop antibodies that recognize the overexpressed p53 protein. The presence of these antibodies is, in some tumour types, associated with poor prognosis. Gastric cancer is a highly prevalent disease associated with a high rate of mortality, there is a need for improved clinical and biological markers for disease behaviour. To investigate the clinical relevance of serum anti-p53 antibodies in patients with gastric adenocarcinoma, we have examined the sera of 501 gastric cancer patients for the presence of serum antibodies against the p53 protein. By immunoblotting analysis using a cell lysate containing overexpressed p53 protein as well as affinity-purified recombinant p53 protein as antigens, we have detected anti-p53 antibodies in 11.2% (61 of 501) of gastric cancer patients, but in none of 46 cancer-free individuals. The presence of anti-p53 antibodies was tightly associated with tumours of higher nuclear grade and lymph node metastasis, and a negative association was found between the presence of anti-p53 antibodies and survival. These results suggest that a preoperative test of serum anti-p53 antibodies in gastric cancer patients can be useful to identify subset of patients who may need gastrectomy with lymph node dissection and post-operative adjuvant therapy.

pH of preparations affecting the on-off drug penetration behavior through the thermo-responsive liquid crystal-embedded membrane

A liquid crystal (cholesteryl oleyl carbonate, COC)-embedded membrane with a controlled rate and higher reversibly thermo-responsive function was successfully fabricated by the vacuum filtration method. The aim of this study was to investigate the effect of the pH of aqueous solutions and gel preparations on the penetration of salbutamol sulfate through this thermo-responsive COC-embedded membrane. The results indicate that the on-off switching penetration behavior of salbutamol sulfate through the COC-embedded membrane in response to a repeatedly exchanging temperature cycle (10 <=> 25 degreesC) is not influenced by the pH of the medium. However, the pH-dependent ionization of salbutamol and the viscosity of the gel base, as well as the interaction between salbutamol and carbopol, might change the amount and the rate of salbutamol sulfate that penetrates across this COC-embedded membrane.

Detection of P450c17-independent pathways for dehydroepiandrosterone (DHEA) biosynthesis in brain glial tumor cells

Dehydroepiandrosterone (D) is biosynthesized in the brain by a pathway different from that existing in the adrenal cortex. C6 rat glioma tumor cells in culture biosynthesize both pregnenolone (P) and D. They possess the mRNA, protein, and side-chain cleavage activity of P450scc. On the other hand, P450c17 was not detected. Adding FeSO4 to C6 cells increased the synthesis of both P and D. Even in the presence of aminoglutethimide, an inhibitor of P450scc, FeSO4 increased the synthesis of both steroids, indicating that the Fe2+-sensitive process does not involve P450scc. Likewise, the FeSO4-induced formation of D was not blocked by the P450c17 inhibitor, SU-10603. These results suggest that the FeSO4-induced synthesis of D as well as of P in C6 cells may be due to the fragmentation of in situ-formed tertiary hydroperoxides. It is likely, however, that the effect of the Fe2+ is not limited to this one reaction. When exogenous P was added to C6 microsomes, along with FeSO4, the amount of D formed was greater than control values, indicating that Fe2+ facilitated the conversion of P to D. Unlike the constituents that are converted by Fe2+ to P, the precursor of D in C6 cells is not soluble in a 1:1 mixture of ether and ethylacetate. Treatment of C6 cells with KI, NaBH4, or HIO4 resulted in an increase in D synthesis. From this it seems clear that a precursor of the D produced in C6 cells is a steroid where both C-17 and C-20 are oxygenated.

Diminished vasomotor component of systemic arterial pressure signals and baroreflex in brain death

We compared the cardiovascular autonomic regulatory mechanisms between patients with brain death or under a persistent vegetative state and healthy volunteers, based on auto- and cross-spectral analysis of systolic blood pressure (SBP) and interpulse interval (PPI) signals. Brain-dead patients exhibited a significant reduction in the absolute and relative power of the low-frequency (LF; 0.04-0.15 Hz) component in both SBP and PPI spectra, along with appreciable decrease in the very low frequency (VLF; 0.004-0.04 Hz), LF, and high-frequency (HF; 0.15-0.4 Hz) power of the PPI signals. Patients in a persistent vegetative state exhibited a power of the VLF and LF component in the SBP spectrum that was comparable to that in healthy subjects, although a discernible reduction in the VLF, LF, and HF power of the PPI spectrum was manifested by the former group. Assessments with the magnitude of SBP-PPI transfer function and linear regression analysis of beat-to-beat fluctuations in SBP and PPI revealed a progressive decline in spontaneous baroreflex sensitivity from healthy subjects to patients in a persistent vegetative state or with brain death. We conclude that the vasomotor component of systemic arterial pressure signals and spontaneous baroreflex are highly correlated with the functional integrity of the brain stem.

Relationship between mesial temporal seizure focus and elevated serum prolactin in temporal lobe epilepsy

We evaluated the relationship between mesial temporal seizure focus and serum prolactin (PRL) in patients before and after they underwent anterior temporal lobectomy (ATL) for medically intractable temporal lobe epilepsy (TLE). These patients had a confirmed unilateral epileptogenic focus in mesial temporal structures, a postictal rise in serum PRL 15 to 20 minutes after onset of complex partial seizures, and were refractory for more than 2 years to antiepileptic drugs. Presurgical interictal serum PRL levels were significantly elevated (16.47 +/- 0.85 ng/mL, n = 62) and declined after ATL to normal values (patients, 9.63 +/- 0.55 ng/mL, n = 54; normal subjects, 8.99 +/- 0.57 ng/mL, n = 52). Serial evaluations indicated that normalization was seen 3 months after surgery (9.42 +/- 1.22 ng/mL, n = 9). The postsurgical reduction in serum PRL was similar in men and women, in patients with epileptogenic focus on either side of mesial temporal structures, and was unaffected by antiepileptic medication. We conclude that PRL is elevated following seizures and that a seizure focus in mesial temporal structures may exert a sustained excitatory influence on PRL release in patients with medically intractable TLE.

Lamotrigine as add-on therapy in adult patients with refractory epilepsy

BACKGROUND

Lamotrigine (LTG), one of the newly developed antiepileptic drugs, is efficacious in treating both partial and generalized seizure disorders including Lennox-Gastaut syndrome. Its effect as an add-on therapy was evaluated in 41 adult Chinese patients with refractory epilepsy. Five of the patients were Lennox-Gastaut syndrome and 36 patients had partial epilepsy.

METHODS

We started LTG at 25 mg or 50 mg per day, respectively, depending on whether the patients were simultaneously taking valproate (VPA) or not. Then, LTG was increased in steps to maximal dosage (200 mg or 400 mg per day) within seven weeks and maintained for three months while pre-existing antiepileptic drugs remained unchanged. The efficacy of LTG therapy was assessed by the reduction in the overall seizure frequency. Hematological and biochemical parameters were checked before and after the trial in all patients.

RESULTS

In all, 38 patients completed the trial. Twenty-two patients (57.9%) had > or = 50% reduction in seizure frequency, including four patients with Lennox-Gastaut syndrome and 18 patients with partial seizures. Among the patients with partial epilepsy, there was no significant difference in the efficacy of LTG whether the seizures were of temporal or extra-temporal origin (p = 0.577). In addition, the efficacy was not determined by the concomitant use of VPA (p = 0.189). Thirteen patients (31.7%) complained of adverse experiences, usually mild and dose-dependent. LTG had to be discontinued in only two patients (4.9%) due to severe side effects. The change in blood cell counts and biochemistry profiles was not significant in any of the patients.

CONCLUSIONS

We conclude that LTG is an efficacious and safe antiepileptic drug for add-on therapy in adult patients with refractory epilepsy.

Six lignans from Phyllanthus myrtifolius

Six lignans comprising phyllamyricins D (1), E (2), and F (3) and phyllamyricosides A (4), B (5), and C (6) were isolated in a continuing study of Phyllanthus myrtifolius. Compounds 1 and 2 are 2a-methoxy-4-aryl-2,3-naphthalides. Compounds 3-6 belong to the 4-arylnaphthalene class, with compounds 4-6 being O-beta-glucosides. Their structures were elucidated on the basis of spectral analysis. Compound 4 increased the activity of HIV-1 reverse transcriptase by 65% at a concentration of 1.89 microM.

Permeation behavior of salbutamol sulfate through hydrophilic and hydrophobic membranes embedded by thermo-responsive cholesteryl oleyl carbonate

PURPOSE

To investigate the suitability of hydrophilic or hydrophobic membranes for use as potential thermo-responsive drug delivery system.

METHODS

Liquid crystal was embedded in membranes using vacuum filtration method to control the penetration rate of salbutamol sulfate. Cholesteryl oleyl carbonate (COC) with smectic-cholesteric phase transition temperature near 18 degrees C was used as a model liquid crystal.

RESULTS

It indicates only hydrophilic salbutamol sulfate can penetrate through the hydrophilic membranes embedded with or without COC, in which the permeation is mainly governed by the adsorption of COC. However, the hydrophilic drug do not pass through the hydrophobic membranes even if not embedded with COC. The void volume of the membrane also influences the penetration of salbutamol sulfate. The higher thermo-response efficacy of the COC-embedded membranes can be explained not only by less permeability through matrix part of the membrane but also by higher thermal motion of the COC molecules due to above the phase transition temperature.

CONCLUSIONS

A COC-embedded membrane with rate-controlled and thermo-responsive function is easily prepared by vacuum filtration method. High reversibly thermo-responsive function can be achieved by choosing membrane and COC concentration properly.

Cytotoxicity and NMR spectral assignments of ergolide and bigelovin

Two potent cytotoxic sesquiterpene lactones, ergolide (1) and bigelovin (2) were isolated from Inula hupehensis I. helianthus-aquatica and their structures and NMR data were assignment unambiguously by using a combination of one-and two-dimensional NMR techniques and computer modeling calculations.

Ictal speech manifestations in temporal lobe epilepsy: a video-EEG study

To evaluate ictal speech manifestations in complex partial seizures (C PS), we reviewed videotapes of 68 consecutive patients who underwent anterior temporal lobectomy (ATL) for treatment of intractable epilepsy in Taiwan. In all, 261 CPS were collected from their video-EEG (VEEG) recordings. Cerebral speech dominance was determined by intracarotid injection of sodium amobarbital (Wada test) in all cases. Ictal speech manifestations, classified as verbalization or vocalization, occurred in 32 patients (47.1%) with 96 seizures (36.8%). Ictal verbalization occurred in 10 patients (14.7%). Ictal vocalization was observed in 28 patients (41.2%); including 6 patients who also had ictal verbalization. Thirty-six patients (52.9%) had no seizure with ictal speech manifestations. Ictal verbalization had significant lateralization value: 90% of patients with this manifestation had seizure focus in the nondominant temporal lobe (p = 0.049). Seizures of patients with ictal vocalization were not more likely to arise from either temporal lobe. We also observed bilingual patients who exclusively spoke in their mother tongue (Taiwanese) rather than the acquired language (Mandarin) in 72.2% of seizures with verbalization. This finding is significant and contrary to a commonly held notion that the acquired language is used in seizures associated with speech behaviors.

Startle epilepsy presenting as drop attacks: a case report

A case of startle epilepsy, induced by an unexpected touch on the left shoulder of a 3.5 year old boy, was investigated. The startle epilepsy manifested as an atonic drop attack. Neurological examination revealed a mild hemiparesis on the left side. Computed tomography (CT) scanning demonstrated an enhancement over the right parieto-frontal region, suggesting a hemangioma. Interictal electroencephalography (EEG) showed diffuse slowing and asymmetry of background activities with lower amplitude over the right centro-parieto-temporal region. The ictal EEG showed a paroxysmal bilaterally synchronized high amplitude single spike followed by a few slow waves lasting about one second over the bilateral centro-parieto-temporal regions. The seizure resisted anticonvulsant therapy and no significant responses were observed despite the use of combined therapy with valproic acid, phenytoin, primidone and clonazepam.

Intravenous immunoglobulin infusion in multifocal demyelinating motor neuropathy: a case report

The following report is a case of multifocal demyelinating motor neuropathy (MMN) presenting as a gradual development of asymmetric motor weakness without sensory involvement. Electrophysiological studies showed mainly a conduction block with normal or slightly slow nerve conduction velocity. Cerebrospinal fluid (CSF) protein and serum protein electrophoresis were normal, but serum IgM anti-GM1 ganglioside antibody was elevated. The patient had a poor response to steroid, plasmapheresis and chemotherapy with cyclophosphamide, but significant improvement was noted after intravenous immunoglobulin (IVIG) infusion. MMN is a potentially treatable condition which clinically mimics a motor neuron disease; if treatment with steroid, plasmapheresis and cyclophosphamide have failed, IVIG may be effective.

Midbrain hemorrhage presenting as bilateral ptosis without hemiplegia: a case report

A 66-year-old man suddenly developed bilateral ptosis after awaking from a nap. He did not experience nausea, vomiting or headache. In the emergency room, high blood pressure was noted. On examination, his consciousness was clear. Ptosis was present bilaterally and worse on the right side. The pupils promptly constricted to light. He could fully adduct his eyes during conjugate gaze movements, but convergence was impaired in the right eye. There was no diplopia or nystagmus. The assessment of the motor and sensory systems revealed no significant findings. Computed tomographic scanning and magnetic resonance imaging of the brain showed a small hematoma in the midbrain. Six months later, ptosis improved; however, the convergence deficit remained.

Hypothalamic hamartoma and gelastic epilepsy: a case report

We studied a 6-year-old girl who presented with inappropriate and uncontrollable laughing episodes since age 3. Physical examination revealed a precocious puberty. The luteinizing hormone-releasing hormone (LH-RH) stimulation test showed an increased level of follicle-stimulating hormone (FSH). The interictal electroencephalogram (EEG) was normal. Several laughing fits were documented during video/EEG monitoring. During laughing, the ictal EEG showed a diffuse suppression of background rhythm, prominent over the left mesial temporal region. A mass lesion about 2 x 2 cm in size was found over the suprasellar cistern with a broad base attached to the hypothalamus, which was isodense on a computed tomography (CT) scan, isointense to gray matter on T1-weighted magnetic resonance (MR) imaging and hyperintense on T2-weighted MR imaging. The findings were suggestive of a hypothalamic hamartoma. A variety of anticonvulsants had been used with little or no response to the frequency or duration of the laughing seizures.

Masseter silent period: a study of magnetic stimulation

We employed magnetic stimulation to study the masseter silent period (SP) in 16 healthy volunteers. Cutaneous perception threshold (CPT or 1 T) was determined. SP threshold was 30% M (maximal output) in each subject, equivalent to 1.5-3 T, and as intensity increased, SP durations prolonged. The correlation was higher with units of % M (r = 0.89) than CPT (r = 0.39). The recommended intensity was 60% M because of least variation of SP durations. Conclusively, magnetic stimulation is a new and painless method to study masseter SP. CPT is less effective in studying masseter SP with magnetic stimulation as the input effectiveness correlates best with % M rather than CPT.

Purification and properties of beta-fructofuranosidase from Aspergillus oryzae ATCC 76080

A fructooligosaccharide-producing beta-fructofuranosidase was purified from the crude extract of Aspergillus oryzae ATCC 76080 through successive steps of ultrafiltration, DEAE-Sepharose CL-6B ion-exchange chromatography, preparative isoelectric focusing electrophoresis and Sephacryl S-200 gel filtration. The purified enzyme had an optimal pH of 5-6, an optimal temperature of 50 degrees C, a Km value of 0.53 M for catalyzing selftransfer reaction from sucrose. The molecular weight was 87 kDa by gel filtration. Mercuric ion (0.25 mM), p-hydroxymercuribenzoate (0.25 mM) and N-bromosuccinimide (0.5 mM), significantly inhibited the enzyme activity. The enzyme showed both transfructosylation and hydrolytic action in 0.5 to 50% sucrose. The transfructosylation ratio increased as the sucrose concentration increased and it was 88.5% at 50% sucrose. The main fructooligosaccharides produced from sucrose were 1-kestose and nystose.

[The effect of intracranial pressure caused by airway suction in hypertensive intracerebral hemorrhagic comatose patients]

Ten hypertensive intracerebral hemorrhagic comatose patients in the Neurosurgical Intensive Care Unit were involved in this study. The ten were within the range of 5 to 8 by Glasgow Coma Scale, and all had undergone tracheostomy. During suction of the airway for 20 seconds in 4 areas (trachea, bronchus, nasal and oral cavities), the data of intracranial pressure (ICP), arterial blood pressure, pulse rate (PR) and respiration rate (RR) were recorded. Results were analyzed for ICP, mean arterial blood pressure (MABP), PR, RR, and cerebral perfusion pressure (CPP) at the 5th, 10th, 15th and 20th seconds in the above-mentioned areas. The ICP was found to be significantly increased, and above the 20 mmHg mark, during suction of the bronchus or nasal cavity for 5 seconds. The MABP also showed significant increase, to above the 110 mmHg mark during 5-second suction of the trachea or nasal cavity or during suction of the bronchus or oral cavity for 10 seconds. However, during the suction of the four airway areas, PR and RR were less influenced and the CPP was not decreased or significantly changed. The conclusion of this study was that suction in the areas of trachea, bronchus and nasal cavity, should not exceed 5 to 10 seconds; in the oral cavity, it may be done within 10 to 15 seconds and at each procedure of airway suction. If it is not possible to clean the sputum or secretion in one procedure, the patient should be allowed to rest for about one minute or become stabilized as determined by watching the monitors of ICP, BP, PR, and RR.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurosyphilis presenting as tabes dorsalis in a HIV carrier

Tabes dorsalis associated with human immunodeficiency virus (HIV) infection is extremely rare. This is a report of a 36-year-old male who had developed unsteady gait for 4 months. Tabes dorsalis was diagnosed by clinical manifestation and CSF examination. HIV antibody was proved by Western blotting. HIV accelerates and alters the natural course of treponemal infection by changing the immunological response of the lues.

Glucose metabolism in mammalian cells as determined by mass isotopomer analysis

A method using 13C isotopes and GCMS/SIM was developed and was used to study glucose metabolism in several mammalian cell lines. Using [U-13C6]glucose, the 13C isotopomer distributions in glucose, lactic acid, glutamic acid, aspartic acid, and gamma-aminobutyric acid produced by the cells were determined, and glycolysis, gluconeogenesis, and the flux into the amino acid pools were calculated. A 1:1 mixture of [U-13C6]glucose and [1-13C]glucose was used to examine the loss of 1-13C carbon from [1-13C]glucose via the pentose monophosphate pathway in the cells; this new method measures the production of [3-13C]lactic acid and [U-13C3]lactic acid, and thus avoids most systematic errors that result from the endogenous production of 12C-lactic acid during metabolic conversion; in addition, glycolysis and the recycling of glucose and lactic acid can be examined at the same time. The mass isotopomer analysis method is reproducible and sensitive, and can be used to analyze metabolites in 10(-7) M concentration with less than 10(5) cultured human cells. This method was used to examine metabolic regulation of glucose in fibroblasts, lymphoblasts, and PC12 cells under various conditions of metabolic disturbance. The method appears to have wide applicability for the study of metabolic regulation of glucose and metabolic defects in cells.

Peptide compositions of the cerebrovascular and senile plaque core amyloid deposits of Alzheimer's disease

The pathological findings of Alzheimer's disease include amyloid deposition in cerebral blood vessels and in senile plaques. Both deposits are known to include peptides that contain a common sequence. Both forms of amyloid were isolated and their peptide compositions were determined. The peptides were resolved by size-exclusion chromatography in 70% formic acid, and reverse-phase chromatography in 60% formic acid, 0-40% acetonitrile. Senile plaque amyloid cores contain about 25% protein, about 70% of which is composed of peptides containing the beta-amyloid sequence. Amino-terminal sequencing of the core amyloid peptides (CAPs) revealed extensive amino-terminal heterogeneity, with variable amounts of blocked amino termini. Matrix-assisted, laser-desorption-time-of-flight mass spectrometry of the CAP mixture revealed an array of peptides the molecular weights of which corresponded to peptides beginning with each of the first 11 amino acids of the beta-peptide sequence and ending with Ala-42 of that sequence. The carboxyl-terminal residues were identified by tandem mass spectrometry of chymotrypsin digests. CAP possessed a minor degree of carboxyl-terminal heterogeneity. Cerebrovascular amyloid peptides (CVAPs) possessed minor degrees of both amino- and carboxyl-terminal heterogeneity. The major CVAP commenced at Asp-1 and ended at Val-40. Minor components of CAP possessed masses of 8000-9000 Da and the same amino-terminal residues as the major components of CAP. They may be precursors to the smaller CAPs. The differences in amino termini and carboxyl termini of CAPs and CVAPs suggest that the two types of amyloid form by different pathways, on which they encounter different proteases.

[An opinion survey of physicians on the impact of National Health Insurance]

In order to further protect the rights of citizens to health care, the government of Taiwan has decided to fully implement the National Health Insurance (NHI) program by 1994. This study examined the opinions of physicians in Taiwan on the impact of the NHI. The data for the analysis came from a mailing survey of 1619 physicians carried out in November 1989 (response rate 21.6%). The results of this study showed: (1) The impact of NHI on the profession: physicians expect their incomes to decrease, workloads to increase, and their professional authonomy to decrease; (2) The impact of the NHI on working conditions: hospital-based physicians expect to decrease the use of medical auxilliary personnel, increase the volume of services, and increase service hours, where as office-based physicians expect the NHI to increase the use of medical auxilliary personnel, increase the volume of services, and increase administrative workload; (3) Half of the physicians expect the NHI will cause the quality of health services to deteriorate. Based on the above findings, this study further discussed the policy and research implications for planning the NHI.

[Latent structure model of physicians' opinions on National Health Insurance]

The purpose of this study is to construct the latent structure models of physicians' opinions on National Health Insurance (NHI). The data for the analysis came from a mail survey of 1619 physicians in January of 1990. Five latent structure models were established as follows: Structure 1. Physicians' viewpoint on NHI. Hospital physicians: Steady, 69%; Turn-Over, 26%; Career-change, 5%. Clinic physicians: Steady-with Insurance Contract, 55%; Steady-without Insurance Contract, 41%; Career-Change, 4%. Structure 2. Physicians' expected impact of NHI. Hospital physicians: Pessimistic, 45%; Disadvantaged, 38%; Constant, 17%. Clinic physicians: Pessimistic, 72%; Constant, 12%; Ambitious, 16%. Structure 3. Physicians' expected workload change due to the implement of NHI. Hospital physicians: Decreasing, 30%; No-Change, 18%; Increasing, 52%. Clinic physicians: Decreasing, 30%; Non-Change, 23%; Increasing, 48%. Structure 4. Ideal practice pattern. Hospital physicians: Traditional, 47%; Transitional, 42%; Practice Abandoned, 12%. Clinic physicians: Traditional, 20%; Transitional, 21%; Rural-Orientated 59%. Structure 5. Expected payment methods for physicians. Hospital physicians: Credentiality-Specialty-based, 44%; Specialty-Equal Pay-based, 11%; Equal Pay-Specialty-based, 42%; Equal Pay-Credentiality-based, 4%. Clinic physicians: Credentiality-based, 24%; Mixed, 11%; Equal Service-Equal Pay-based, 60%; Urbanization Level-based, 5%.

The effect of plasticizers on compatibility, mechanical properties, and adhesion strength of drug-free Eudragit E films

The use of plasticizers to affect the properties of drug-free, self-adhesive Eudragit E-100 films with higher transparency was tested for possible transdermal drug delivery. Triacetin was found to be an effective first plasticizer for Eudragit E-100 polymer. In order to improve the flexibility and adhesiveness of Eudragit E-100 film plasticized with triacetin, a more flexible and adhesive, secondary plasticizer was added. Plasticizer-polymer compatibility was evaluated by measuring transparency, surface topography, and solubility. Secondary plasticizers with a low molecular weight and a solubility parameter similar to that of Eudragit E-100 polymer and triacetin were compatible. Further, a lower molecular weight or higher concentration of the secondary plasticizers might lead to greater plasticizing action, reduce tensile strength, and increase film elongation, independent of the hydrophilicity of the plasticizer. The adhesive strength of Eudragit E-100 film under a 180 degrees peel test was also affected by the molecular weight and solubility parameter of the secondary plasticizers used. The results indicate that PEG 200, propylene glycol, diethyl phthalate, and oleic acid can serve as a secondary plasticizer to improve the transparency, flexibility, and adhesion of Eudragit E-100 film.

13C-NMR study of taurine and chlorotaurine in human cells

13C-NMR with 13C-enriched taurine [( 13C]taurine) has been utilized to study the formation and reactions of N-chlorotaurine in solution and in human cells. Taurine reacts instantaneously with HOCl at pH 7.0 to form N-chlorotaurine, which is stable in solution by itself. In the presence of alpha-amino acids, a chlorine transfer reaction taken place to produce N-chloroamino acids, which quickly convert to the corresponding aldehydes. [13C]Taurine was incubated with human neutrophils and with cultured human lymphoblastoid cells and 13C-NMR spectra of the whole cell mixtures were acquired in order to examine the formation of N-chlorotaurine from reaction between taurine and the endogenous HOCl produced by myeloperoxidase-catalyzed reactions (Zgliczynski, J.M., et al. (1968) Eur. J. Biochem. 4, 540; Weiss, S.J., et al. (1982) J. Clin. Invest. 70, 598). The presence of N-chlorotaurine in the cells was not detected on the 13C-NMR spectra. On the other hand, N-chloro[13C]taurine incubated with the cells was found to be converted to taurine, which must have been produced by a chlorine transfer reaction of the N-chlorotaurine to other cellular components such as amino acids, peptides or proteins. A 13C-NMR study of taurine uptake in human lymphoblastoid cells indicated that taurine is incorporated into a freely mobile intracellular pool. These results suggest that the presence of abundant taurine in a freely mobile intracellular pool may serve as a buffer in preventing oxidative damage to the cells from attacks by HOCl or other oxidants.

Selection of a derivative of the antiviral agent 9-[(1,3-dihydroxy-2-propoxy)-methyl]guanine (DHPG) with improved oral absorption

Various diesters of 9-[(1,3-dihydroxy-2-propoxy)-methyl]guanine (DHPG) were screened in order to identify a derivative with improved oral absorption. The solubilities and dissolution rates decreased with increasing chain length and branching of the ester group. However, the dipropionate ester showed an anomalously faster dissolution rate. The rates of hydrolysis to DHPG in the presence of intestinal homogenates were found to increase with increasing carbon number for the straight-chain alkyl esters and decreased with branching. The shorter-chain alkyl esters were relatively more stable in intestinal homogenates than in liver homogenates. Therefore they may have a better membrane permeability than DHPG due to their intact ester group. The hydrolysis rates in human blood increased with increasing carbon number for the straight-chain alkyl esters. The dipropionate ester appeared to be the most promising derivative because of its rapid dissolution rate, slower hydrolysis in the intestine, and rapid conversion to DHPG in liver and blood.

Stable isotope study of plasma taurine kinetics in rhesus monkey

Taurine is one of the most abundant amino acids in mammals and there is increasing evidence for the importance of taurine during development. Plasma taurine kinetics in a rhesus monkey was studied using [1,2-13C2]taurine. Taurine in plasma was derivatized to its dimethylaminomethylene methyl ester, separated on a gas chromatographic column, and the [M+2+H]+/[M+H]+ ion ratio was measured by ammonia chemical ionization mass spectrometry. The results were comparable to those obtained from the simultaneous radioisotope tracer study using [35S]taurine. This stable isotope method requires only 200 microliters of plasma for precise and accurate determination and is suitable for taurine kinetic studies in human infants.

N-acetylneuramin lactose sulfate: a newly identified nutrient in milk

The identity of a sulfate ester in rat milk has been determined to be N-acetylneuramin lactose sulfate. This sulfate ester is present in rat mammary tissue and in human milk. The presence of this compound offers an explanation for the simultaneous delivery of sulfate and calcium via the milk, two essential nutrients in early life, without precipitation of calcium sulfate in the milk. N-acetylneuramin lactose sulfate is hydrolyzed in the gut of the neonate and absorbed as inorganic sulfate. This is the first report suggesting that this ester may be of nutritional importance.

Improved diagnosis of classical vs atypical phenylketonuria by liquid chromatography

Atypical phenylketonuria among infants with hyperphenylalaninemia must be promptly diagnosed and differentiated from classical phenylketonuria, because these patients require different treatment to prevent irreversible neurological damage. Measurement of pteridines in urine by liquid chromatography has been widely used for this purpose. Here we report a rapid, simplified liquid-chromatographic method for simultaneously measuring urinary biopterin, neopterin, and creatinine. Unlike previous methods, this method involves neither tedious cleanup procedures nor special equipment.

Improved diagnosis of classical vs atypical phenylketonuria by liquid chromatography

Atypical phenylketonuria among infants with hyperphenylalaninemia must be promptly diagnosed and differentiated from classical phenylketonuria, because these patients require different treatment to prevent irreversible neurological damage. Measurement of pteridines in urine by liquid chromatography has been widely used for this purpose. Here we report a rapid, simplified liquid-chromatographic method for simultaneously measuring urinary biopterin, neopterin, and creatinine. Unlike previous methods, this method involves neither tedious cleanup procedures nor special equipment.

Nuclear magnetic resonance imaging techniques as developed modestly within a university medical center environment: what can the small system contribute at this point?

This paper describes a geometrically small NMR imaging system which has been developed and assembled within a university medical center environment. Consideration is given to the technical specifications and basic economics for the magnet system, NMR spectrometer, and computer configuration. Initial research objectives for the system are outlined which include (1) the signal-to-noise improvement potential of rotational gradient imaging, and (2) 19F tracer imaging considerations with a detailed discussion concerning the feasibility of in vivo NMR imaging of 19F-fluorodeoxyglucose (2-FDG and 3-FDG). Finally, potentially significant areas for research within the constraints of a small NMR imaging system are described.

Identification of steroids by chemical ionization mass spectrometry

Chemical ionization (CI) mass spectra of various natural and synthetic steroids have been studied using methane, isobutane, ammonia, trideuterioammonia and hydroxy anion as reagent gases. The CI spectra of steroids give simple and well characterized ions, which provide information about molicular weight as well as functionalities in the molecules. Trideuterioammonia exchanges rapidly with active hydrogens (e.g., OH, SH, COOH, NH2) in steroid molecules in the CI reaction and thus provides a convenient means of active hydrogen determination by mass spectrometry, Application of various CI processes to the analysis of steroids and conjugates have been made. Low levels of hydroxycholesterols in biological samples and in cholesterol autoxidation products were identified by the 4 ion patterns, [M+NH4]+, [M-OH+NH3]+, [M-0H]+ and [M-H2 O-OH]+, in ammonia CI. The position of hydroxy functions in the cholesterol side chain can be identified from the methane CI of hydroxycholesterol trimethylsilyl (TMS) derivatives. Sterol carboxylic esters can be identified as the ammonium adduct ion of the intact molecule, [M+NH4]+, in ammonia CI. Isobutane and hydroxy anion CI spectra of the steroid esters give abundant ion fragments of both steroids and carboxylic acid moieties. Identification of free bile acids and steroid glycosides without derivatization is also feasible with the CI process when ammonia is used as reagent gas.

High pressure liquid chromatographic separation of two major toxic compounds from Gymnodinium breve davis

Cultured Gymnodinium breve cells were extracted in acidified ether and fractionated by a new, convenient procedure utilizing thin layer chromatography or elution dry column chromatography. The most toxic fraction was further separated either directly by analytical high pressure liquid chromatography (HPLC) or in subsequent work by preparative, followed by analytical HPLC. Two toxic compounds, designated T46 and T47, were isolated; purity of each was demonstrated by rechromatography in analytical HPLC with both adsorptive and reverse phase packings. Both the single pass and recycle modes of operation were used with two detector systems in each to demonstrate a single entity. UV, fluorescence, and stability data differentiated these compounds from previously described, less toxic components from G. breve.