Molecular cloning and sequence analysis of the monkey and human tissue kallikrein genes

Cynomolgus monkey renal kallikrein cDNA and genomic human tissue kallikrein gene were cloned. The monkey gene encodes a 257 amino acid (aa) preprokallikrein and exhibits 95% and 92% homology to the human at nucleotide (nt) and aa level, respectively. The monkey gene encodes a 233-aa mature kallikrein versus a 238-aa in human. The human kallikrein gene and urinary kallikrein both contain a Lys-162 instead of the reported Glu-162. Human, monkey and rat renal/pancreatic kallikrein genes evolve with a N-glycosylation containing domain (aa 81-87) which is absent in porcine and is non-glycosylable in mice. Only human kallikrein evolves with an additional Thr-108 and with a N-glycosylation site at aa-141.

Tuning the activity of an enzyme for unusual environments: sequential random mutagenesis of subtilisin E for catalysis in dimethylformamide

Random mutagenesis has been used to engineer the protease subtilisin E to function in a highly nonnatural environment--high concentrations of a polar organic solvent. Sequential rounds of mutagenesis and screening have yielded a variant (PC3) that hydrolyzes a peptide substrate 256 times more efficiently than wild-type subtilisin in 60% dimethylformamide. PC3 subtilisin E and other variants containing different combinations of amino acid substitutions are effective catalysts for transesterification and peptide synthesis in dimethylformamide and other organic media. Starting with a variant containing four effective amino acid substitutions (D60N, D97G, Q103R, and N218S; where, for example, D60N represents Asp-60-->Asn), six additional mutations (G131D, E156G, N181S, S182G, S188P, and T255A) were generated during three sequential rounds of mutagenesis and screening. The 10 substitutions are clustered on one face of the enzyme, near the active site and substrate binding pocket, and all are located in loops that connect core secondary structure elements and exhibit considerable sequence variability in subtilisins from different sources. These variable surface loops are effective handles for "tuning" the activity of subtilisin. Seven of the 10 amino acid substitutions in PC3 are found in other natural subtilisins. Great variability is exhibited among naturally occurring sequences that code for similar three-dimensional structures--it is possible to make use of this sequence flexibility to engineer enzymes to exhibit features not previously developed (or required) for function in vivo.

Site-directed mutagenesis of monoamine oxidase A and B: role of cysteines

Nine cysteines are found in the deduced amino acid sequences of both human liver monoamine oxidase (MAO)-A and MAO-B. The role of these cysteine residues in MAO-A and -B catalytic activity was studied by site-directed mutagenesis, whereby each cysteine residue was converted to serine. The wild-type and mutant cDNAs were then transiently transfected into COS cells and assayed for MAO-A and -B catalytic activity using 5-[3H]hydroxytryptamine and [14C]phenylethylamine, respectively, as substrates. Catalytic activities were retained in seven MAO-A cysteine to serine mutants (mutations at residues 165, 210, 266, 306, 321, 323, and 398) and in six MAO-B cysteine to serine mutants (mutations at residues 5, 172, 192, 297, 312, and 389). Kinetic parameters (Km) of these mutants were also similar to those of the wild-type enzymes, indicating that these cysteines are not necessary for enzymatic activity. Substitution of MAO-A Cys-374 and -406 and MAO-B Cys-156, -365, and -397 with serine resulted in complete loss of MAO-A and -B catalytic activity. The loss of catalytic activity was not due to unsuccessful transfection of the mutants, as indicated by either Northern blot or Western blot analysis. The loss of catalytic activity in the MAO-A Ser-406 and MAO-B Ser-397 mutants may be due to the prevention of covalent binding of the enzyme to the cofactor FAD, which is necessary for catalytic activity. The loss of catalytic activity of MAO-A Ser-374 and MAO-B Ser-156 and -365 suggests that these cysteines are important for catalytic activity, but whether they are involved in forming the active site or are important for the appropriate conformation of MAO-A and -B remains to be studied.

[Gastric emptying time with 99mTc-resin solid experiment meal]

Half gastric emptying time (GET1/2) was measured by using radionuclide gamma-photography with 99mTc-resin solid experiment meal. The results were as follows: 1. GET1/2 in the normal controls (10 cases) was 51.62 +/- 3.69 minutes. 2. GET1/2 in mild chronic atrophic gastritis (CAG) patients was 51.68 +/- 9.20 Min, not significantly different with the normal controls (P > 0.05). GET1/2 in 15 cases with moderate and severe CAG was 70.39 +/- 14.86 Min, which was apparently longer than that in normal controls (P < 0.01). 3. There was no significant difference in GET1/2 between carcinoma of the gastric corpus, fundus and cardia (50.77 +/- 2.73 Min) as well as the normal controls (P > 0.05). GET1/2 of the cancer of gastric antrum was 89.06 +/- 19.55 Min, being longer than that in normal controls (P < 0.01). 4. No obvious difference was observed between the GET1/2 of patients with corpus and fundus peptic ulcer (55.36 +/- 6.80 Min.) and the normal controls (P > 0.05). It was apparently longer in patients with antral peptic ulcer (76.62 +/- 16.96 Min.) than in patients with ulcers of corpus, fundus and normal controls (P < 0.01). 5. GET1/2 in patients with duodenal ulcer (42.49 +/- 6.26 Min.) was apparently shorter than those with gastric ulcer and normal controls. 6. GET1/2 in diabetic patients was 70.01 +/- 29, 46 Min, it was obviously longer in those patients with autonomic nervous dysfunction (84.03 +/- 22.31 Min.) than that those without (34.14 +/- 7.90 Min.).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor stimulates the tyrosine phosphorylation of SHC in the mouse

Previous studies have demonstrated that the administration of epidermal growth factor (EGF) to neonatal mice results in the tyrosine phosphorylation of multiple substrates in all organs examined (Donaldson, R. W., and Cohen, S. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 8477-8481). One of these substrates, a 55-kDa protein, was shown to associate with the receptor for EGF (EGFR). We now report the identification of this receptor-associated protein as SHC. Immunoprecipitation and Western blotting analyses have revealed that SHC associates only with the activated EGFR. In the absence of EGF stimulation, SHC exists in the liver as a cytoplasmic monomer. Intraperitoneal injection of EGF results, within minutes, in the translocation of 50-80% of SHC to the liver plasma membrane. The membrane-associated SHC was found to be tyrosine-phosphorylated; the subsequent release of SHC from the membrane correlated with a tyrosine dephosphorylation. We conclude that SHC is a physiological substrate that appears to participate in the in vivo signaling response to EGF.

Dysfunctional platelet glycoprotein IIb/IIIa associated with a platelet release defect: a family study

We are reporting on a 36-year-old white female with a bleeding history attributed to dysfunctional platelet glycoprotein IIb/IIIa (GPIIb/IIIa) and a coexisting platelet release defect. Platelet aggregation studies (PAS) revealed markedly diminished to absent responses to ADP, epinephrine, collagen and arachidonic acid; the ristocetin response was normal. ATP content was normal with poor release to the agonists as measured by luminescent technique. DDAVP infusion shortened bleeding time from 13.5 min to 8.0 and 12 min (at 1 and 2 hours). Flow cytometry and immunoblotting revealed normal amounts of GPIIb and diminished GPIIIa (50% of control). Using a previously reported ELISA which measures the binding of GPIIb/IIIa to immobilized fibrinogen, the patient's platelet extract showed no binding to fibrinogen. Both the father and mother were found to have decreased PAS responses and normal amounts of GPIIb/IIIa determined by both Western blot and flow cytometry. However, the ELISA showed decreased binding of their GPIIb/IIIa to fibrinogen (71% and 62% as compared to controls, respectively). The patient's dysfunctional fibrinogen receptor was clearly demonstrated by the ELISA. The parents had moderately reduced GPIIb/IIIa function in this assay, but they did not demonstrate a reduced GPIIIa as was noted in the patient. The parents' PAS indicated a platelet release defect. These findings suggest an inherited platelet release defect and a dysfunctional GPIIIa. The partial response to DDAVP would be compatible with the presence of a platelet release defect.

Longitudinal Gompertzian analysis of non-Hodgkin's lymphoma mortality in the US, 1979-1988: demonstration of the environmental basis for rising overall mortality

Between 1979 and 1988, annual crude non-Hodgkin's lymphoma mortality rates (per 100,000) in the United States increased from 3.43 to 6.34 among men (an 85% increase in only 10 years) and, among women, increased from 2.82 to 5.71 (a 102% increase). Age-specific mortality rates for non-Hodgkin's lymphoma from 1979 through 1988 were subjected to longitudinal Gompertzian analysis, a method that may be able to identify and distinguish among genetic, environmental and competitive influences upon evolving mortality trends. The results of this analysis suggest that the basis for the dramatic rise in non-Hodgkin's lymphoma mortality is due to worsening environmental influences. The capability to distinguish between environmental and competitive influences upon evolving mortality patterns has significant public health policy implications.

Moderately severe osteogenesis imperfecta associated with substitutions of serine for glycine in the alpha 1(I) chain of type I collagen

We have examined the type I collagen protein, RNA, and cDNA of 2 children with moderately severe (type IV) osteogenesis imperfecta (OI). They have in common a non-lethal form of OI with ambulatory potential, overmodification of type I collagen protein, and a substitution of serine for glycine in the collagen chain produced by one alpha 1(I) allele. The first child (Marini et al.: J Biol Chem 264:11893-11900, 1989) is now 7 years old, with the height of a 3-year-old. Her course includes significant remodeling of lower long bones and 4 femur fractures. She walks independently. A mishmatch was detected in her alpha 1(I) mRNA using RNA/RNA hybrids; it was demonstrated to be due to a G-->A point mutation in one allele of alpha 1(I), resulting in the substitution of serine for glycine 832. The second child is now 6 1/2 years old, with the height of 1 1/2-year-old. Her history includes significant bowing of femurs and tibias, 6 femur fractures, S-curve scoliosis, compression of all lumbar vertebrae, and limited short-distance walking with braces. Her alpha 1(I) mRNA has also been studied by RNA hybrid analysis; there is a single G-->A change in one alpha 1(I) allele causing the substitution of serine for gly 352. Both children have moderately severe OI. However, the serine substitution at gly 352 is associated with a more severe phenotype then is the serine substitution at gly 832. Compared to substitutions described in other cases of OI, the serine 352 is located in the middle of a cluster of cysteine substitutions associated with non-lethal OI.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of human platelet glycoprotein IIB/IIIA binding to fibrinogen by tumor cell membrane proteins

Immunochemical and functional characteristics of tumor cell membrane proteins and human platelet glycoproteins were studied. Immunoblotting revealed that membrane proteins of a cultured breast tumor cell line (BT-20) had three protein bands, which were each recognized by monoclonal antibodies to human platelet glycoprotein Ib, IIb, and IIIa, suggesting some immunochemical similarities between the tumor cell membrane proteins and platelet glycoproteins. The monoclonal antibodies failed to bind to an extract of a lung tumor cell line (A549). Neither tumor extract induced platelet aggregation. However, tumor-associated antigens isolated from the breast tumor cells markedly inhibited platelet glycoprotein IIb/IIIa binding to fibrinogen. In contrast, tumor-associated antigens from the lung tumor cells had no effect. These results suggest that tumor cells which have immunological and/or structural similarities to platelets may affect hemostasis and coagulation in vivo.

Structure and promoter organization of the human monoamine oxidase A and B genes

Monoamine oxidase (MAO) A and B play an important role in regulating levels of biogenic amines. MAO A and B cDNAs have been cloned and the deduced amino acids share 73% sequence identity. The genes for MAOA and B are comprised of 15 exons interspersed by 14 introns, span at least 60 kb and exhibit identical exon-intron organization. These findings suggest that the MAOA and MAOB genes are derived from the duplication of a common ancestral gene. The core promoter region of MAOA is comprised of two 90 bp repeats, each of which contains two Spl elements and lacks a TATA box. The MAOB core promoter region contains two sets of overlapping Spl sites which flank a CACCC element all upstream of a TATA box. The different organization of the MAOA and MAOB promoters may underlie their different cell and tissue specific expression.

[An applied study on the method of multi-factorial quantitative-risk assessment (MFQRA) for mass screening of colorectal cancer]

This paper reported an actual effectiveness evaluation for MFQRA, as a primary screening procedure, applied in a mass screening for colorectal cancer since 1989 to 1990 among a general population with the age of 30 and above in Jia-shan county where is a high incidence area of colorectal cancer in this nation. Results of this paper demonstrated that (1) attributable degree (AD) can identify subpopulations or subgroups with different incidence risks from a general population, and provide evidence for decision-making of advanced screening procedures and even for prevention of colorectal cancer; (2) Sensitivity of MFQRA was much higher, compared to conventional fecal occult blood test (FOBT) and symptomatic screening methods (65.89% vs 34%-50%); (3) Multiple tests with FOBT by reverse passive hemagglutination (RPHA) were effective and practical method for mass screening of colorectal cancer.

[Active life expectancy in Taiwan: compression or expansion?]

"This paper applies the multiple-decrement life table to the analysis of mortality and self-reported disability [for Taiwan], annually from 1986 until 1989.... It was found that during this period of time, the shifts in 'mortality' and 'disability' curves conform to the compression hypothesis. The area in between the two curves [has] shrunk in the 4 year period.... The sex differential in disability has been examined. It is concluded that though at the younger ages women tend to spend less person-years in disability, the situation is quite different at older ages. Women tend to have greater chance [of] and longer duration suffering from disability at old age than men." (SUMMARY IN ENG)

Promoter organization and activity of human monoamine oxidase (MAO) A and B genes

Monoamine oxidase A and B (MAO A and B) play important roles in the metabolism of biogenic and dietary amines and are encoded by two genes derived from a common ancestral gene. The promoter regions for human MAO A and B genes have been characterized using a series of 5' flanking sequences linked to a human growth hormone reporter gene. When these constructs were transfected into NIH3T3, SHSY-5Y, and COS7 cells, the maximal promoter activity for MAO A was found in a 0.14 kilobase (kb) PvuII/DraII fragment (A0.14) and in a 0.15 kb PstI/NaeI fragment (B0.15) for MAO B. Both fragments are GC-rich, contain potential Sp1 binding sites, and are in the region where the MAO A and B 5' flanking sequences share the highest identity (approximately 60%). However, the organization of the transcription elements is distinctly different between these two promoters. Fragment A0.14 consists of three Sp1 elements, all in reversed orientations, and lacks a TATA box. Two of the Sp1 sites are located within the downstream 90 base pair (bp) direct repeat, and the third is located at the 3' end of the upstream 90 bp direct repeat. Fragment B0.15 contains an Sp1-CACCC-Sp1-TATA structure; deletion of any of these elements reduced promoter activity. Additional Sp1 sites, CACCC elements, CCAAT boxes, and direct repeats (four 30 bp direct repeats in MAO A and two 29 bp direct repeats in MAO B) are found in farther-upstream sequences of both genes (1.27 kb for MAO A and mostly in 0.2 kb for MAO B). Inclusion of these sequences decreased promoter activity. The different promoter organization of MAO A and B genes provides the basis for their different tissue- and cell-specific expression.

Gene structure and expression of the mouse 5-HT2 receptor

Serotonin (5-hydroxytryptamine, 5-HT) is an important neurotransmitter which mediates numerous physiological functions. Using the SacI-EcoRI restriction fragment of the rat brain 5-HT2 receptor cDNA as a probe, we have screened a mouse brain cDNA library, created by random priming and constructed in SWAJ vectors, and have isolated a cDNA encoding a 1.4 kb open reading frame which codes for a functional mouse 5-HT2 receptor identified from pharmacological binding profiles and coupling of phosphoinositide formation in a stably transfected fibroblast cell line. The deduced amino acid sequence is 97.4% identical to the rat 5-HT2 receptor. Using the same 5-HT2 receptor cDNA probe, ten positive genomic clones were isolated from two mouse genomic libraries constructed in the pWE15 cosmid vector and the EMBL-3 phage vector. Extensive mapping and sequencing of these genomic clones indicate the mouse 5-HT2 receptor coding region spans over 20 kb and is composed of three exons split by two introns. Northern blot analysis shows one band of 5-6 kb in the mouse brain, but not in the heart, lung, liver, or kidney total RNA. Southern analysis of mouse liver genomic DNA shows a simple pattern of digestion by several restriction enzymes, which suggests that one copy of the 5-HT2 receptor gene may exist in the mouse genome.

Ischemic stroke treated with Ligusticum chuanxiong

Ligusticum Chuanxiong and its effective components were studied in the treatment of ischemic stroke, a common emergent disease in China. Some injections of the medicines, including Ligusticum, Ligustrazine, Ligustylid and ferulic acid, were tested clinically and experimentally. The results showed that the effects of the drugs were the same as or even better than those of the controls, such as papaverine, dextran and aspirin-persantin. They could improve brain microcirculation through inhibiting thrombus formation and platelet aggregation as well as blood viscosity.

Anaesthetic management of a parturient with myocardial infarction related to cocaine use

Cocaine abuse is common among parturients with an incidence of 11.8 to 20%. Myocardial infarction is a rare and lethal event during pregnancy with an incidence of 1 in 10,000 pregnancies. We present the anaesthetic management of a parturient of 36 wk gestation who suffered a myocardial infarction nine hours before delivery which was temporally related to "crack" cocaine use. The patient's cardiovascular system became unstable following cocaine use, and she required mechanical ventilatory support and pharmacologic stabilization guided by invasive haemodynamic monitoring. This patient survived a non-Q wave myocardial infarction, but the prognosis of peripartum myocardial infarction remains poor with a mortality rate of 30-40% which is increased if the infarction occurs in the third trimester or postpartum period. The optimal mode and timing of delivery after myocardial infarction is unresolved. The association between cocaine use and myocardial infarction was first described in 1982, and cocaine remains unique among local anaesthetics in its ability to compromise the cardiovascular system through both sympathomimetic effects and vasoconstrictive effects on coronary arteries. Because of the prevalence of substance abuse, cocaine use should be considered in the differential diagnosis of sudden cardiovascular compromise in parturients.

Pulmonary Kaposi's sarcoma in Africa

BACKGROUND

A study was carried out to identify the main clinical radiological and bronchoscopic features of HIV related Kaposi's sarcoma of the lung in African patients.

METHODS

Forty seven HIV positive patients with epidemic Kaposi's sarcoma who had clinical or radiological respiratory changes were investigated by simple lung function tests and fibreoptic bronchoscopy.

RESULTS

The most common respiratory symptoms in the 47 patients were persistent cough in 42, haemoptysis in 23, and breathlessness in 38. A restrictive spirometric pattern was most common. The mean (SD) forced expiratory volume in one second (FEV1) was 1.88 (0.62) 1 with a forced vital capacity (FVC) of 2.66 (0.87) 1 and a FEV1/FVC% of 73.2 (7.5). On the chest radiograph 26 patients had diffuse reticulonodular shadows, 11 focal nodular shadows, seven a pleural effusion, and one a substantial increase in vascular markings; in two the radiograph was normal. At bronchoscopy characteristic discrete lesions were easily visible in 37 patients and were often bright red. Multiple nodules were seen in 11, flat or early plaque lesions in 12 (14 had both), proximal flat lesions and diffuse infiltration in three, diffuse infiltration alone in four, and masses in two; one had normal appearances at bronchoscopy. One patient had Pneumocystis carinii and two had a single bacterial pathogen cultured from the bronchoalveolar lavage fluid. Only two of 29 bronchoscopic biopsies showed classical histological Kaposi's sarcoma. After cytotoxic treatment 20 patients have died, with an overall median survival of 70 days.

CONCLUSION

In this African population symptomatic pulmonary Kaposi's sarcoma was common, with lesions seen in all but one patient at bronchoscopy. Coexistent infection was uncommon. Prognosis was poor despite treatment.

Stages of progression in drug involvement from adolescence to adulthood: further evidence for the gateway theory

Sequential stages of involvement in alcohol and/or cigarettes, marijuana, other illicit drugs and medically prescribed psychoactive drugs from adolescence to adulthood are investigated in a longitudinal cohort that has been followed from ages 15 to 35. Alternative models of progression are tested for their goodness of fit. Four stages are identified: that of legal drugs, alcohol or cigarettes; marijuana; illicit drugs other than marijuana; and medically prescribed drugs. Whereas progression to illicit drugs among men is dependent upon prior use of alcohol, among women either cigarettes or alcohol is a sufficient condition for progression to marijuana. Age of onset and frequency of use at a lower stage of drug use are strong predictors of further progression.

Metastasis-associated alterations in phospholipids and fatty acids of human prostatic adenocarcinoma cell lines

Metastatic variants of human prostatic adenocarcinoma cell lines (DU-145, LNCaP, and ND-1) were studied by using soft agar colony forming efficiency, nude mice tumorigenicity, in vitro invasion assay, and type IV collagenase assay. The DU-145 and ND-1 cell line showed higher metastatic potential than LNCaP. Lipids from DU-145, ND-1, and LNCaP cells were extracted and analyzed by thin-layer chromatography and gas-liquid chromatography. The major lipids were phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, fatty acids, and cholesterol. The sphingomyelin level was significantly higher in highly metastatic cells (DU-145 and ND-1) compared with the lower metastatic variant (LNCaP). The increase in the synthetic pathway and decrease in degradation pathway of sphingomyelin in microsomal fractions was sufficient to account for the measured increase in sphingomyelin in DU-145 cells compared with LNCaP cells. The major fatty acids of these lipids were palmitic (16:0), stearic (18:0), oelic (18:1), and arachidonic acid (20:4). The arachidonic acid level was significantly decreased in DU-145 and ND-1 compared with LNCaP cells. Electron microscopic studies showed no significant changes in the morphology of DU-145, ND-1, and LNCaP cells. The results of these investigations demonstrate for the first time that sphingomyelin and arachidonic acid contents are different in high and low metastatic variants of human prostatic adenocarcinoma cell lines.

Inflammatory leukocytes associated with increased immunosuppression by glioblastoma

In order to determine the in vivo immune response in glioblastoma, monoclonal and polyclonal antibodies specific for inflammatory leukocytes and immunoregulatory products were utilized to stain tissue from four surgical specimens. The more activated the inflammatory cells, the more activated the tumors appeared to be. In the tumor with the largest infiltration (Case 3), inflammatory cells were stained for interferon-gamma, interleukin-2, interleukin-1 beta, lymphotoxin, tumor necrosis factor-alpha, and transforming growth factor-beta. The tumor cells also expressed interleukin-1 beta, interleukin-6, transforming growth factor-beta, tumor necrosis factor-alpha, and prostaglandin E. In contrast, in the tumor with the least inflammatory response (Case 1), the tumor cells did not express any cytokines. Expression of cytokines by glioma cells was modest in the two cases with modest inflammatory responses. Cellular inflammation, primarily consisting of T cells and macrophages with few or no B cells or natural killer cells, was two- to 15-fold greater outside the tumor than within. In contrast to leukocytes outside the tumor, which were activated and expressing class II major histocompatibility antigens, leukocytes within the tumor parenchyma or at the tumor's edge were negative for these antigens. In the four specimens studied here, the tumor cells themselves were also negative for class II major histocompatibility antigens. These findings, although preliminary, suggest that inflammatory cells within gliomas are inactivated and that glioma cells may increase the expression of immunosuppressive cytokines in response to an increased lymphocyte infiltrate. This observation, if corroborated by more extensive studies, may help to explain the failure of immune treatments in glioblastoma multiforme.

Dynamic interactions of biofilms of mucoid Pseudomonas aeruginosa with tobramycin and piperacillin

The dynamic interaction of planktonic and biofilm cells of mucoid Pseudomonas aeruginosa with tobramycin and piperacillin was investigated in a chemostat system. The results indicated that planktonic and young biofilm cells of the 2-day-old chemostat culture of P. aeruginosa were susceptible to killing by chemostat-controlled doses of either 250 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml or 500 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml. Complete eradication of the planktonic and young biofilm cells was observed after exposure of the cells to six chemostat-controlled doses of these antibiotic at 8-h intervals for 7 days. Regrowth of the organism was not observed after the termination of antibiotic therapy on day 7. A different picture was observed when antibiotic treatment was initiated on day 10 after inoculation. Viable old biofilm cells were reduced to approximately 20% after exposure to the chemostat-controlled doses of 500 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml. Complete eradication of old biofilm cells could not be achieved, and regrowth of the organism occurred after the termination of antibiotic therapy. These data suggest that young biofilm cells of mucoid P. aeruginosa can be effectively eradicated with the combination of piperacillin and tobramycin, while old biofilm cells are very resistant to these antibiotics and eradication of old biofilm cells is not achievable with the chemostat-controlled doses of piperacillin and tobramycin used in this study.

The human 5-HT2 receptor is encoded by a multiple intron-exon gene

Serotonin (5-hydroxytryptamine; 5-HT) mediates many central and peripheral nervous system functions by its interaction with specific neuronal receptors. Here we report the genomic structure of the human 5-HT2 receptor. The SacI-EcoRI restriction fragment of rat 5-HT2 receptor cDNA was used as a probe to identify and isolate two positive clones of 8.5 and 7.0 kb from an EcoRI restriction digest of a chromosome 13 specific EcoRI fragment lambda-phage human genomic library. Subcloning and sequencing of these fragments showed the 8.5 kb fragment (designated lambda SE-5) contained the first two exons of the 5-HT2 receptor gene. The 7.0 kb insert (lambda SE-2) contained an incomplete third exon. A HindIII-EcoRI fragment of this insert was used as a probe to isolate a 9.0 kb clone (lambda SH-2), which contained the entire third exon, from a chromosome 13 specific HindIII-fragment lambda-phage human genomic library. The isolation of these three clones (lambda SE-5, lambda SE-2 and lambda SH-2) shows that the human 5-HT2 receptor gene consists of three exons separated by two introns and spans over 20 kb. The deduced amino acid sequence of the human, mouse and rat 5-HT2 receptors are highly conserved and all three share a 90% sequence similarity.

Selective suppression of lipid resonances by lipid-soluble nitroxides in NMR spectroscopy

The ability of lipid-soluble nitroxides to suppress selectively the peaks of lipid resonances in 31P, 1H, and 13C NMR spectra was investigated in serum as part of studies aimed at using these contrast agents for magnetic resonance imaging and magnetic resonance spectroscopy in vivo. Nitroxides are especially interesting potential contrast agents because they can reversibly be converted in cells to diamagnetic hydroxylamines, with conversion rates that are dependent on the redox potential and the intracellular concentration of oxygen; the characterization of nitroxide-dependent changes in NMR spectra may therefore be a useful means to measure oxygen-dependent redox metabolism in vivo. The fatty acid analogs, doxyl stearates, suppressed the methyl resonance of choline and the methyl and methylene peaks of lipids in the 1H NMR spectra of serum samples. As a consequence, lactate peaks, which were not readily detected became clearly resolved and could be evaluated quantitatively. The 31P resonance of phosphatidylcholine in the 31P NMR spectrum was suppressed by 5-doxyl stearate and 4-(N,N-dimethyl-N-hexadecyl)ammonium-2,2,6,6-tetramethylpiperidine-1-oxy l,iodid e (Cat16). In the 13C NMR spectrum, the resonances of the methyl groups of choline and the lipids also were broadened significantly by addition of 5-doxyl stearate. Differential suppression of lipid resonances can be employed to facilitate quantitation of lactate.

Protein disulfide isomerase activity is released by activated platelets

The release of protein disulfide isomerase by activated platelets was hypothesized on the basis of reported intermolecular and intramolecular thiol-disulfide exchange and disulfide reduction involving released thrombospondin in the supernatant solution of activated platelets (Danishefsky, Alexander, Detwiler: Biochemistry, 23:4984, 1984; Speziale, Detwiler: J Biol Chem, 265:17859, 1990; Speziale, Detwiler: Arch Biochem Biophys 286:546, 1991). Protein disulfide isomerase activity, measured by catalysis of the renaturation of ribonuclease inactivated by randomization of disulfide bonds, was detected in the supernatant solution after platelet activation. The activity was inhibited by peptides known to inhibit protein disulfide isomerase; the peptides also inhibited formation of disulfide-linked thrombospondin-thrombin complexes. The reaction catalyzed by the supernatant solution showed a pH dependence distinct from that of the uncatalyzed reaction. The activity was excluded by a 50-Kd dialysis membrane, and it was eluted in the void volume of a gel-filtration column, indicating that it was associated with a macromolecule. The activity was not removed by centrifugation at 100,000 g for 150 minutes indicating that it was not associated with membrane microvesicles. Possible functions for the release of protein disulfide isomerase by activated platelets are discussed.

Prospective versus retrospective methods of identifying patients with delirium

OBJECTIVE

To determine if DSM-III criteria or clinical or discharge diagnoses, reviewed retrospectively, are as accurate an indicator of the presence of delirium as prospective evaluation by a psychiatrist.

DESIGN

Selection of delirious patients prospectively by a psychiatrist, followed by retrospective record review of the same patients.

SETTING

A referral-based university hospital.

PATIENTS

From a sample of 235 consecutive medical patients over age 70, 47 delirious patients were identified prospectively by a research psychiatrist using DSM-III criteria. The medical record of these delirious patients was reviewed after discharge for evidence of delirium.

RESULTS

Four patients were assigned ICD-9 codes suggestive of delirium (sensitivity 0.09). Review of physicians' diagnoses correctly identified 8 of 47 (sensitivity 0.17) patients as being delirious or acutely confused. The specific diagnostic criteria necessary to meet a DSM-III diagnosis of delirium could be ascertained from 10 of 47 records (sensitivity 0.21).

CONCLUSION

The retrospective medical record review is very imprecise in establishing the diagnosis of delirium. As research in this field moves from descriptive epidemiology to studies of pathogenesis and treatment, prospective designs will be needed.

The contraction of stunned myocardium: isovolumetric bulging and wasted ejection shortening in dog heart

OBJECTIVE

The aim of the study was to assess the contraction of myocardium stunned by repetitive brief coronary occlusions by examining the response to alterations in loading and inotropy of systolic contraction on isovolumetric and ejection phase shortening.

METHODS

Fourteen open chest anaesthetised dogs were used for the studies. After destruction of the sinus node, the heart was atrially paced and atrial extrasystoles were introduced followed by a short (400 ms) or long (700 ms) postextrasystole. The left anterior descending coronary artery was occluded for 5 min and reperfused for 10 min a total of eight times to produce stunned myocardium, followed by a final 60 min of reflow. Regional function was assessed with segment length sonomicrometers.

RESULTS

With successive periods of occlusion there was an increase in the end diastolic segment length and a progressive decrease in total percent systolic shortening (baseline 22.3%, 1st reflow 14.5%, 8th reflow 7.9%) with some recovery after 60 min of reflow (12.0%). This was predominantly due to the development of bulging during isovolumetric systole (4.5%, -4.9%, and -8.3%, respectively) which diminished during 60 min recovery to -3.1%. Ejection shortening was relatively constant (17.8%, 19.4%, 16.3%, and 15.1%, respectively). Postextrasystolic potentiation resulted in an increased in total percent systolic shortening, but not to the baseline value, as slight isovolumetric bulging persisted. Similar changes were seen with the short and long postextrasystoles although the latter had a greater increase in ejection shortening.

CONCLUSIONS

The decrease in function after repetitive occlusion and reflow is predominantly due to bulging during isovolumetric systole which persists after postextrasystolic potentiation in our model of stunned myocardium.

Zn(II) coordination domain mutants of T4 gene 32 protein

Gene 32 protein (g32P), the replication accessory single-stranded nucleic acid binding protein from bacteriophage T4, contains 1 mol of Zn(II)/mol of protein. Zinc coordination provides structural stability to the DNA-binding core domain of the molecule, termed g32P-(A+B) (residues 22-253). Optical absorption studies with the Co(II)-substituted protein and 113Cd NMR spectroscopy of 113Cd(II)-substituted g32P-(A+B) show that the metal coordination sphere in g32P is characterized by approximately tetrahedral ligand symmetry and ligation by the Cys-S- atoms of Cys77, Cys87, and Cys90. These studies predicted the involvement of a fourth protein-derived non-thiol ligand to complete the tetrahedral complex, postulated to be His81 on the basis of primary structure prediction and modeling [Giedroc, D.P., Johnson, B.A., Armitage, I.M., & Coleman, J.E. (1989) Biochemistry 28, 2410-2418]. To test this model, we have employed site-directed mutagenesis to substitute each of the two histidine residues in g32P (His64 and His81), accompanied by purification and structural characterization of these single-site mutant proteins. We show that g32P's containing any of three substitutions at residue 64 (H64Q, H64N, and H64L) are isolated from Escherichia coli in a Zn(II)-free form [less than or equal to 0.03 g.atom Zn(II)]. All derivatives show extremely weak affinity for the ssDNA homopolymer poly(dT). All are characterized by a far-UV-CD spectrum reduced in negative intensity relative to the wild-type protein. These structural features parallel those found for the known metal ligand mutant Cys87----Ser87 (C87S) g32P. In contrast, g32P-(A+B) containing a substitution of His81 with glutamine (H81Q), alanine (H81A) or cysteine (H81C), contains stoichiometric Zn(II) as isolated and binds to polynucleotides with an affinity comparable to the wild-type g32P-(A+B). Spin-echo 1H NMR spectra recorded for wild-type and H81Q g32P-(A+B) as a function of pH allow the assignment of His81 ring proteins to delta = 6.81 and 6.57 ppm, respectively, at pH 7.8, corresponding to the C and D histidyl protons of 1H-His-g32P-(A+B) [Pan, T., Giedroc, D.P., & Coleman, J.E. (1989) Biochemistry 28, 8828-8832]. These resonances shift downfield as the pH is reduced from 7.8 to 6.6 without metal dissociation, a result incompatible with His81 donating a ligand to the Zn(II) in wild-type g32P. Likewise, Cys81 in Zn(II) H81C g32P is readily reactive with 5,5'-dithiobis(2-nitrobenzoic acid), unlike metal ligands Cys77, Cys87, and Cys90.(ABSTRACT TRUNCATED AT 400 WORDS)

The use of contextual information in the reversible compression of medical images

The authors investigate the use of conditioning events (or contexts) in improving the performances of known compression methods by building a source model with multiple contexts to code the decorrelated pixels. Three methods for reversible compression, namely DPCM (differential pulse code modulation), WHT (Walsh-Hadamard transform), and HINT (hierarchical interpolation), employing, respectively, predictive decorrelation, transform decorrelation, and multiresolution decorrelation, are considered. It is shown that the performance of these methods can be enhanced significantly, sometimes even up to 40%, by using contexts. The enhanced DPCM method is found to perform the best for MR and UT (ultrasound) medical images; the enhanced WHT method is found to be the best for X-ray images. The source models used in the enhanced models employ several hundred contexts.

Computer 3-dimensional reconstruction of intraglandular lymph vessels and ductal systems of the human submandibular gland

Computer three-dimensional reconstruction of serial sections is currently an active area of research. In this paper we combine computer graphics, image processing and biomedical techniques to reconstruct a stereo model of intraglandular lymphatic vessels, veins, arteries and ducts from serial microsections of the human submandibular gland.

Anti-AIDS agents, 4. Tripterifordin, a novel anti-HIV principle from Tripterygium wilfordii: isolation and structural elucidation

A new kaurane-type diterpene lactone, tripterifordin [1], has been isolated from the roots of Tripterygium wilfordii. The structure of 1 was elucidated by spectroscopic methods, including the concerted application of a number of 2D nmr techniques that involved the 1H-1H COSY, heteronucleus-detected variants of the heteronuclear chemical shift correlation (HETCOR), phase-sensitive NOESY, and long-range HETCOR. Compound 1 shows anti-HIV replication activity in H9 lymphocyte cells with an EC50 of 1 microgram/ml.

Evidence for phase-locking response to hypoxia in peripheral chemoreceptor activity in man

A number of animal studies have demonstrated that the ventilatory response to stimulation of the peripheral chemoreceptors is well reproduced only when it is stimulated during inspiratory period. In humans, such a response has not been confirmed when using a mild hypoxic stimulus. We, therefore, hypothesized that this response may be detected when a more intense hypoxia is applied. To confirm this hypothesis, six healthy subjects inhaled N2 gas mixture with 5% CO2 in an amount of vital capacity. This procedure started from steady state mild hypoxia (PET02; 60-70 mmHg). Inspiratory and expiratory minute ventilation (VI and VE), tidal volume (VT), and inspiratory and expiratory time (TI and TE) of the breath, at the start of falling oxygen saturation, were analyzed. 21% O2 + 5% CO2 balanced with N2 was inhaled and a breath cycle with a similar latency as during N2 gas mixture inhalation was also analyzed as a control. When oxygen saturation began to drop at the inspiratory phase, the increment of ventilation and tidal volume were larger than the control. When it occurred at the expiratory phase, no significant difference from the control was seen. These results signify the presence of rectification of chemoreceptor afferent signal in humans and may support the concept of oscillation hypothesis as an effective ventilatory stimulus.

Contrast agents for magnetic resonance spectroscopy: a method to obtain increased information in in vivo and in vitro spectroscopy

The concept of contrast, which now is an integral part of many magnetic resonance imaging studies, can be extended successfully to magnetic resonance spectroscopy. It involves the use of paramagnetic molecules whose distribution is restricted in some manner, thereby causing differential effects on the NMR spectra. As an illustrative example, the effects of lipophilic nitroxide stable free radicals on the NMR spectra of serum and lipoproteins are shown. These nitroxides differentially broaden away components of the spectra due to the nuclei of methylene and methyl groups, which enables the usually obscured peaks of lactate to be observed fully. The concept can be applied to differential distribution of the contrast agent on the basis of solubility, charge, and/or compartmentalization. It can be used with any type of NMR spectroscopy and any type of paramagnetic contrast (broadening) agent.

Molecular biology of serotonin (5-HT) receptors

The recent cloning of three types of 5-hydroxytryptamine (5-HT, serotonin) receptors substantiates radioligand-based definitions of 5-HT receptors, and provides a framework in which to understand the function and evolution of the receptors. The primary sequences determined by molecular cloning of the 5-HT1c, 5-HT1a and 5-HT2 receptors place each of these 5-HT receptor subtypes into the class of G protein-coupled receptors. These receptors all share similar functional and structural features. Each receptor is positioned in the lipid bilayer with seven membrane-spanning domains and corresponding intracellular and extracellular domains. By analogy to the known functional structures of the beta-adrenergic receptor, the binding site of 5-HT is proposed to be in the membrane domains and the intracellular domain is important for G protein interaction. The primary sequences and the second messenger systems of the receptors indicate the 5-HT2 and 5-HT1c receptors are closely related, whereas the 5-HT1a receptor is more distantly related to the 5-HT2 and 5-HT1c receptors.

NGF improves spatial memory in aged rodents as a function of age

Aged rats were tested for place navigation in a circular water maze for spatial memory ability at 18 and 30 months of age; 45% of the 18-month-old rats displayed impaired place navigation performance relative to young control rats, while essentially all of the 30-month-old rats were impaired. The aged impaired rats were retested twice during NGF or vehicle infusion in the right lateral ventricle. In the 18-month-old group, NGF-infused rats showed improved retention of previously acquired place navigation performance and improved spatial acuity over the former platform site when the invisible platform was removed. NGF infusion also had a significant effect in the much more severely impaired 30-month-old rats: while the vehicle-infused aged rats showed a progressive decline in the performance between the first and second test weeks, the performance of the NGF-infused rats remained stable throughout the infusion period. The interpretation of these effects in the oldest animals, however, was confounded by a progressive decline in swim speed seen in the vehicle-infused animals. The 30-month-old vehicle-infused control rats showed a significant cell loss and cell shrinkage relative to the young control rats in the septal/diagonal band area, the striatum, and the nucleus basalis as assessed by NGF-receptor (NGFr) and ChAT double-label immunocytochemistry. A significant increase in the size but not in the number of cells was observed on the side of the NGF infusion in the 30-month-old NGF-infused rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Human monoamine oxidase A and B genes exhibit identical exon-intron organization

Monoamine oxidases A and B [MAOA and MAOB; amine:oxygen oxidoreductase (deaminating) (flavin-containing), EC 1.4.3.4] play important roles in the metabolism of neuroactive, vasoactive amines and the Parkinsonism-producing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Human MAOA and MAOB genes isolated from X chromosome-specific libraries span at least 60 kilobases, consist of 15 exons, and exhibit identical exon-intron organization. Exon 12 codes for the covalent FAD-binding-site and is the most conserved exon; the MAOA and MAOB exon 12 products share 93.9% peptide identity. These results suggest that MAOA and MAOB are derived from duplication of a common ancestral gene and provide insight on the structural/functional relationship of the enzyme products.

Reproductive factors and colorectal cancer risk among Chinese females

We report results from a population-based case-control study of colorectal cancer among Chinese women in western North America (NA) and the People's Republic of China (China). A common protocol was used to assess reproductive characteristics and hormone use of 395 Chinese women (189 from NA and 206 from China) with cancer of the colon or rectum and of 1112 age-matched Chinese controls (494 from NA and 618 from China). In NA, risks for cancers of both the colon and rectum were lower among parous compared to nulliparous women (odds ratio for colorectal cancer, 0.6, P = 0.08), but the trend in risk was not smooth with increasing number of livebirths. This association with parity was absent for both cancer sites in China. There were no consistent patterns in the relationships between other reproductive factors (including age at menarche, age at first livebirth, menopausal status) and risk of colon and rectal cancer on either continent.

[Comparison of Spatholobus suberectus Dum, Euonymus alatus (Thunb.) Sieb. and Eupolyphaga sinensis Walker on regulation of plasma lipid]

The Spatholobus suberectus (SS) of hexue type, the Euonymus alatus (EA) of huoxue type and the Eupolyphaga sinensis (ES) of poxue type were selected and their influence on plasma lipid in the experimental hyperlipidemia quails was observed. The ES could raise plasma HDL-C/TC ratio and increase LCAT activity. The SS could raise plasma HDL2-C/HDL3-C ratio. The effect of EA on plasma HDL-C/TC, HDL2-C/HDL3-C and LCAT levels was between SS and ES. All the three huoxue huayu Chinese drugs could lower plasma HDL3-C level and slow down the progress of atherosclerosis to a certain degree. The above-mentioned results show that certain orders exist between the action range of huoxue huayu drugs and their effect on regulating plasma lipid.

Cellular metabolism of proxyl nitroxides and hydroxylamines

Previous data from model systems indicated that the proxyl nitroxides should be especially resistant to bioreduction and therefore could be an effective solution to this often problematic characteristic of nitroxides. Therefore, we investigated the rate of reduction by cells and by the usual model system, ascorbate, of four proxyl nitroxides and three reference nitroxides. We found that, while the rate of reduction by ascorbate of the proxyl nitroxides was slower than the rate of a prototypic pyrrolidine nitroxide (PCA), the reverse was true for reduction by cells. We also studied the rate of oxidation of the corresponding hydroxylamines. The rate of oxidation by cells of the proxyl hydroxylamines was relatively fast, especially for the most lipophilic derivative. These results indicate that: (i) proxyl nitroxides may not be unusually resistant to bioreduction by functional biological systems; (ii) accurate knowledge of relative rates of metabolism of nitroxides and hydroxylamines in cells and tissues will require direct studies in these systems because the rates may not closely parallel those observed in model (chemical) systems; and (iii) proxyl nitroxides show potential value as agents to measure oxygen concentrations by the rates of oxidation of their corresponding hydroxylamines.