Differentiation of Bartonella-like isolates at the species level by PCR-restriction fragment length polymorphism in the citrate synthase gene

The citrate synthase gene (gltA) of Bartonella henselae was cloned and sequenced to compare genetic divergence among alpha and gamma branches of the class Proteobacteria and to develop enhanced genotypic reagents for B. henselae identification. B. henselae gltA is 1,293 nucleotides in length and 63 to 66% homologous with corresponding gene sequences of Rickettsia prowazekii, Escherichia coli, and Coxiella burnetii. The observed genetic variability suggests that gltA sequences can provide a useful means for studying moderate divergence among related bacteria. Oligonucleotides specific for B. henselae gltA were evaluated for the ability to prime PCR amplification within the alpha and gamma branches of the proteobacteria. Under the conditions used, only B. henselae, Bartonella quintana, and R. prowazekii template DNAs yielded amplification products (approximately 380 bp). DNAs from 28 Bartonella-like isolates of feline origin were amplified by B. henselae primers and analyzed for restriction fragment length polymorphism. The resulting patterns for all 28 isolates were similar or identical to that of the recognized B. henselae strain. Current studies are aimed at optimization of PCR conditions for specificity and sensitivity of amplification of Bartonella sequences from clinical isolates.

Adhesion properties of mutants of Staphylococcus aureus defective in fibronectin-binding proteins and studies on the expression of fnb genes

Staphylococcus aureus 8325-4 has the potential to express two distinct cell wall-associated fibronectin-binding proteins called FnBPA and FnBPB. In order to test if both proteins are expressed in S. aureus and if both are required for promoting bacterial adhesion to fibronectin-coated surfaces, insertion mutations were isolated in each gene. A DNA fragment encoding tetracycline resistance was inserted into fnbA and a fragment encoding erythromycin resistance was inserted into fnbB. A double fnbAfnbB mutant was also constructed. The fnbA and fnbB single mutants showed no significant reduction in their adhesion to polymethylmethacrylate coverslips that had been coated in vitro with fibronectin. However, the double mutant was completely defective in adhesion. Monospecific antibodies directed against the non-conserved N-terminal regions of both proteins confirmed the lack of expression of FnBPs in the mutant strains. Wild-type fnbA and fnbB genes cloned seperately on a multicopy plasmid were each able to restore fully the adhesion-defective phenotype of the 8325-4 fnbAfnbB mutant. This demonstrates that both fnb genes are expressed in S. aureus and that both contribute to the ability of strain 8325-4 to adhere to fibronectin-coated surfaces. The double mutant was also defective in adhesion to coverslips that had been removed from tissue cages implanted subcutaneously in guinea-pigs, which suggests that fibronectin is important in promoting attachment of S. aureus to biomaterial in vivo.

Accumulation of phosphorylated neurofilaments in anterior horn motoneurons of amyotrophic lateral sclerosis patients

Perikaryal collections of intermediate filaments have been described in the anterior horn motoneurons of patients with amyotrophic lateral sclerosis (ALS), but these inclusions have generally been considered rare and mainly associated with the familial form of ALS. Using the monoclonal antibody NF2F11, which recognizes phosphorylated neurofilament epitopes, we showed that focal collections of neurofilaments in anterior horn motoneurons were a characteristic finding in sporadic as well as in familial ALS; they were present in seven of nine ALS patients, but in none of nine control spinal cords. These neurofilamentous collections are not cross-reactive with antibodies directed against paired helical filaments and the microtubule associated protein tau. In addition, diffuse staining for phosphorylated neurofilament epitopes in chromatolytic anterior horn perikarya was significantly more frequent in ALS patients than in controls.

Innate immunity in cystic fibrosis lung disease

Chronic lung disease determines the morbidity and mortality of cystic fibrosis (CF) patients. The pulmonary immune response in CF is characterized by an early and non-resolving activation of the innate immune system, which is dysregulated at several levels. Here we provide a comprehensive overview of innate immunity in CF lung disease, involving (i) epithelial dysfunction, (ii) pathogen sensing, (iii) leukocyte recruitment, (iv) phagocyte impairment, (v) mechanisms linking innate and adaptive immunity and (iv) the potential clinical relevance. Dissecting the complex network of innate immune regulation and associated pro-inflammatory cascades in CF lung disease may pave the way for novel immune-targeted therapies in CF and other chronic infective lung diseases.

Prevalence of Bartonella henselae antibodies in pet cats throughout regions of North America

Cat exposure has been directly associated with the development of human Bartonella henselae infections, resulting in cat-scratch disease, bacillary angiomatosis, or bacteremia. The prevalence of serum antibody titers to B. henselae was determined for selected pet cats from 33 geographic locations throughout the United States and several areas in western Canada. Seroprevalences paralleled increasing climatic warmth (P < .02) and annual precipitation (P < .03). These warm, humid areas with the highest seroprevalence would also have the highest number of potential arthropod vectors. The southeastern United States, Hawaii, coastal California, the Pacific Northwest, and the south central plains had the highest average prevalences (54.6%, 47.4%, 40.0%, 34.3%, and 36.7%, respectively). Alaska, the Rocky Mountain-Great Plains region, and the Midwest had low average prevalences (5.0%, 3.7%, and 6.7%, respectively). Overall, 27.9% (175/628) of the cats tested were seropositive. The seroprevalence of B. henselae in cats varies throughout the United States and appears to be influenced by climate.

Dose-dependent expression of claudin-5 is a modifying factor in schizophrenia

Schizophrenia is a neurodevelopmental disorder that affects up to 1% of the general population. Various genes show associations with schizophrenia and a very weak nominal association with the tight junction protein, claudin-5, has previously been identified. Claudin-5 is expressed in endothelial cells forming part of the blood-brain barrier (BBB). Furthermore, schizophrenia occurs in 30% of individuals with 22q11 deletion syndrome (22q11DS), a population who are haploinsufficient for the claudin-5 gene. Here, we show that a variant in the claudin-5 gene is weakly associated with schizophrenia in 22q11DS, leading to 75% less claudin-5 being expressed in endothelial cells. We also show that targeted adeno-associated virus-mediated suppression of claudin-5 in the mouse brain results in localized BBB disruption and behavioural changes. Using an inducible 'knockdown' mouse model, we further link claudin-5 suppression with psychosis through a distinct behavioural phenotype showing impairments in learning and memory, anxiety-like behaviour and sensorimotor gating. In addition, these animals develop seizures and die after 3-4 weeks of claudin-5 suppression, reinforcing the crucial role of claudin-5 in normal neurological function. Finally, we show that anti-psychotic medications dose-dependently increase claudin-5 expression in vitro and in vivo while aberrant, discontinuous expression of claudin-5 in the brains of schizophrenic patients post mortem was observed compared to age-matched controls. Together, these data suggest that BBB disruption may be a modifying factor in the development of schizophrenia and that drugs directly targeting the BBB may offer new therapeutic opportunities for treating this disorder.

Short-chain acyl-coenzyme A dehydrogenase deficiency. Clinical and biochemical studies in two patients

We describe two patients with short-chain acyl-coenzyme A (CoA) dehydrogenase (SCADH) deficiency. Neonate I excreted large amounts of ethylmalonate and methylsuccinate; ethylmalonate excretion increased after a medium-chain triglyceride load. Neonate II died postnatally and excreted ethylmalonate, butyrate, 3-hydroxybutyrate, adipate, and lactate. Both neonates' fibroblasts catabolized [1-14C]butyrate poorly (29-64% of control). Neonate I had moderately decreased [1-14C]octanoate catabolism (43-60% of control), while neonate II oxidized this substrate normally; both catabolized radiolabeled palmitate, succinate, and/or leucine normally. Cell sonicates from neonates I and II dehydrogenated [2,3-3H]butyryl-CoA poorly (41 and 53% of control) and [2,3-3H]octanoyl-CoA more effectively (59 and 95% of control). Mitochondrial acyl-CoA dehydrogenase (ADH) activities with butyryl- and octanoyl-CoAs were 37 and 56% of control in neonate I, and 47 and 81% of control in neonate II, respectively. Monospecific medium-chain ADH (MCADH) antisera inhibited MCADH activity towards both butyryl- and octanoyl-CoAs, revealing SCADH activities to be 1 and 11% of control for neonates I and II, respectively. Fibroblast SCADH and MCADH activities were normal in an adult female with muscular SCADH deficiency.

Seroprevalence of Bartonella henselae infection and correlation with disease status in cats in Switzerland

The prevalence of infection with Bartonella henselae was investigated in cats from different areas of Switzerland. Serum samples of 728 cats were examined for antibodies to B. henselae by immunofluorescent antibody testing, and the results were analyzed with a view to a possible correlation between a positive titer and signalment, clinical signs, infection with feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline coronavirus (FCoV), or feline spumavirus (FeSFV), and the living environments of the cats. The seroprevalence in all cats was 8.3%. No significantly different prevalence was found in sick versus healthy cats (9.2 versus 7.2%); however, in sick cats seropositive for B. henselae, there was an increased frequency of stomatitis and a variety of diseases of the kidneys and the urinary tract. There was an increased prevalence of B. henselae in cats positive for FCoV (P = 0.0185) or FeSFV (P = 0.0235) and no statistically significant increased prevalence in cats infected with FeLV or FIV. There was no correlation between a positive titer and sex or breed. The same prevalence of B. henselae antibodies was found in cats with and without access to the outdoors and in cats from single- and multicat households. The seroprevalence was increased in cats living south of the Alps (12.1%); however, this difference was not significant (P = 0.0616).

Maternal exposure to prescription and non-prescription pharmaceuticals or drugs of abuse and risk of craniosynostosis

BACKGROUND

The pre- and peri-natal drug exposures reported by women participating in a case-control study of children in Colorado were examined for association with infant craniosynostosis.

METHODS

Mothers of case and control children underwent a standardized telephone interview and obstetric and newborn medical record review. The interview included questions on the use of prescription and non-prescription drugs, nutritional supplements, recreational and drugs of abuse. The mother's obstetric record was abstracted for information about pharmacologic agents taken before and during the antepartum period.

RESULTS

There were no statistically significant risk ratios associating craniosynostosis with prenatal exposure to hydantoin, valproic acid, or cocaine. Mothers of four case children and one control child reported specific exposure to retinoic acid. There were no statistically significant increases in the odds ratio (OR) for any suture type among children exposed to hypoxigenic agents, sympathomimetic or parasympatholytic agents, or metal-containing agents. The OR was 1.87 (lower bound of the two-sided 95% test-based confidence interval (CI): 1.08) among children with sagittal/lambdoid suture synostosis who were exposed to nitrosatable drugs chlorpheniramine, chlordiazepoxide, and nitrofurantoin compared to controls.

CONCLUSIONS

Certain nitrosatable drugs may be associated with increased risk of infant sagittal/lambdoid craniosynostosis. A possible mechanism related to ischaemia/reperfusion injury is suggested.

Hepatitis C in state correctional facilities

BACKGROUND

No previous studies have examined the extent to which correctional facilities in the United States screen for and treat hepatitis C (HCV) infection.

METHODS

Medical directors of state correctional facilities responded to a survey assessing the degree to which prisons screen for and treat hepatitis C. To estimate numbers of inmates eligible for interferon treatment and to examine costs associated with HCV management, we constructed a feasibility model that incorporated screening criteria used in California and Rhode Island.

RESULTS

Thirty-six states and Washington, DC, responded, resulting in a survey response rate of 73%, representing 77% of all inmates in state facilities nationwide. Colorado alone reported routine screening. Only California reported conducting a systematic seroprevalence study, which found that 39.4% of male inmates were hepatitis C antibody positive in 1994. Seventy-three percent of the respondents sometimes consider treating with interferon. Four states follow a standard protocol. The feasibility model suggests that treating suitably screened inmates is a reasonable expenditure for correctional systems.

CONCLUSION

Prison may be an appropriate setting for treatment of hepatitis C. If accompanying substance abuse issues are addressed, instituting HCV treatment for certain eligible incarcerated individuals may be a worthy target for public health dollars.

Meiotic studies in two human reciprocal translocations and their association with spermatogenic failure

BACKGROUND

Reciprocal translocations are often associated with infertility in male carriers. However, some carriers present normal semen profiles and are identified because of repetitive pregnancy failures.

METHODS

Here, we report two different cases of reciprocal translocations. The first patient carried a t(10;14) and was normozoospermic. The second patient carried a t(13;20) and was azoospermic. Synaptonemal complexes from both carriers were analysed using immunocytogenetic techniques and multi-centromere fluorescent in situ hybridization (cenM-FISH).

RESULTS

Associations between the quadrivalent and the sex body or other autosomes were seen only in the t(13;20) carrier. Heterosynapsis was observed only in the t(10;14) carrier. Synaptic pairing abnormalities were seen in 71% of the spreads in the t(13;20) carrier and 30% of the spreads in the t(10;14) carrier. Recombination frequency was decreased in the t(13;20) carrier, but not in the t(10;14) carrier.

CONCLUSIONS

By comparing these two different translocation carriers with different fertility outcomes, we discuss the possible mechanisms by which translocations might cause the spermatogenesis process to fail.

Canine leptospirosis infections - clinical signs and outcome with different suspected Leptospira serogroups (42 cases)

OBJECTIVES

The aim of the study was to investigate the presence of serum antibodies to different Leptospira serogroups in dogs with a clinical diagnosis of leptospirosis in southern Germany and to compare seroreactivity to different serogroups with history, clinical signs, laboratory findings and survival rate.

METHODS

In this study, the data of 42 dogs with the diagnosis of leptospirosis were evaluated retrospectively. Dogs were presented to the Small Animal Medicine Teaching Hospital (Medizinische Kleintierklinik) of the Ludwig Maximilians University Munich, Germany, between 1990 to 2003.

RESULTS

Reactivity to the serogroup grippotyphosa (13/42) was most frequently present, followed by reactivity to the serogroup saxkoebing (10/42). There was no difference in the clinical picture and the laboratory changes between dogs whose sera were reactive to different serogroups.

CLINICAL SIGNIFICANCE

Most of the dogs with leptospirosis in southern Germany had sera reacting to serogroups other than icterohaemorrhagiae and canicola, which are contained in the vaccine. Thus, currently available vaccines in Europe do not protect against the most common Leptospira organisms associated with clinical disease.

Cryosurgery for prostate cancer: improved glandular ablation by use of 6 to 8 cryoprobes

OBJECTIVES

To describe and assess the efficacy for increased glandular destruction by using 6 to 8 cryoprobes in place of the traditional 5 probes.

METHODS

In April 1996, a revised method for cryosurgery was begun that uses 6 to 8 cryoprobes, and by July 1997, 81 men had been treated. This group was compared retrospectively to our last 82 cases done before April 1996 using 5 cryoprobes. All cases were consecutive. To ensure that the groups were similar, comparison was performed of entrance prostate-specific antigen (PSA), clinical stage, and Gleason score. Six months after cryosurgery, PSA and residual epithelial acini were compared between the two groups.

RESULTS

The two groups were comparable for all the above parameters (P >0.05). The degree of overall glandular kill was greater for the 6 to 8-probe method (P = 0.023). Complete glandular ablation for the 5-probe and 6 to 8-probe methods was 39% and 53%, respectively, and the difference was not significant (P = 0.072). However, when one combined the complete glandular ablation group with the none to few residual acini group, 67.5% for the 5-probe method and 88.9% for the 6 to 8-probe method, a significant difference was found (P = 0.001). The odds of having many remaining acini versus having none to few were 3.5 times greater in the 5-probe group than in the 6 to 8-probe group. The mean and median PSA for the 5- and 6 to 8-probe groups were 0.19 and 0.1 versus 0.11 and 0.07 ng/mL, respectively, a significant difference (P = 0.02). No difference was found in rates of tumor persistence or complications.

CONCLUSIONS

A revised method for cryosurgery using 6 to 8 cryoprobes has proved to be more effective for near-glandular ablation than the traditional 5-probe method. It was easily applied, had a wide margin of safety, and even shortened learning time. These innovations have permitted a closer approach to the goal of complete glandular destruction.

Evaluation of the ability of Acinetobacter baumannii to form biofilms on six different biomedical relevant surfaces

The human opportunistic pathogen, Acinetobacter baumannii, has the propensity to form biofilms and frequently cause medical device-related infections in hospitals. However, the physio-chemical properties of medical surfaces, in addition to bacterial surface properties, will affect colonization and biofilm development. The objective of this study was to compare the ability of A. baumannii to form biofilms on six different materials common to the hospital environment: glass, porcelain, stainless steel, rubber, polycarbonate plastic and polypropylene plastic. Biofilms were developed on material coupons in a CDC biofilm reactor. Biofilms were visualized and quantified using fluorescent staining and imaged using confocal laser scanning microscopy (CLSM) and by direct viable cell counts. Image analysis of CLSM stacks indicated that the mean biomass values for biofilms grown on glass, rubber, porcelain, polypropylene, stainless steel and polycarbonate were 0·04, 0·26, 0·62, 1·00, 2·08 and 2·70 μm(3) /μm(2) respectively. Polycarbonate developed statistically more biofilm mass than glass, rubber, porcelain and polypropylene. Viable cell counts data were in agreement with the CLSM-derived data. In conclusion, polycarbonate was the most accommodating surface for A. baumannii ATCC 17978 to form biofilms while glass was least favourable. Alternatives to polycarbonate for use in medical and dental devices may need to be considered.

SIGNIFICANCE AND IMPACT OF THE STUDY

In the hospital environment, Acinetobacter baumannii is one of the most persistent and difficult to control opportunistic pathogens. The persistence of A. baumannii is due, in part, to its ability to colonize surfaces and form biofilms. This study demonstrates that A. baumannii can form biofilms on a variety of different surfaces and develops substantial biofilms on polycarbonate - a thermoplastic material that is often used in the construction of medical devices. The findings highlight the need to further study the in vitro compatibility of medical materials that could be colonized by A. baumannii and allow it to persist in hospital settings.

Increased risk of craniosynostosis with maternal cigarette smoking during pregnancy

We analyzed data from a population-based case control study to determine whether maternal prenatal smoking or alcohol drinking might increase the risk of craniosynostosis. Between 1986 and 1989, the Colorado Craniosynostosis Registry ascertained 233 children whose diagnoses were confirmed by an independent radiologist. Of the 212 (91%) cases who participated 86 had lambdoid, 69 had sagittal, 25 had coronal, 18 had metopic, and 14 had multiple suture synostosis. Random sampling of birth certificate records yielded 367 eligible controls, of whom 291 (79%) participated. Study staff interviewed case and control mothers between 1989 and 1991 for prenatal smoking and alcohol drinking. We used Mantel-Haenszel and polychotomous logistic regression techniques to estimate the relative odds of craniosynostosis for smoking and drinking in all cases and in relevant case subgroups. Smoking was associated with a relative odds of craniosynostosis of 1.7 (95% confidence interval, 1.2-2.6). For smoking of more than one pack per day, the relative odds were 3.5 (1.5-8.4) for all types of synostosis combined, and 5.6 (2.1-15.3) for coronal synostosis. No strong or significant association was noted for drinking. Maternal prenatal smoking may increase the risk of craniosynostosis in this population.

Immunofluorescent synaptonemal complex analysis in azoospermic men

The molecular cause of germ cell meiotic defects in azoospermic men is rarely known. During meiotic prophase I, a proteinaceous structure called the synaptonemal complex (SC) appears along the pairing axis of homologous chromosomes and meiotic recombination takes place. Newly-developed immunofluorescence techniques for SC proteins (SCP1 and SCP3) and for a DNA mismatch repair protein (MLH1) present in late recombination nodules allow simultaneous analysis of synapsis, and of meiotic recombination, during the first meiotic prophase in spermatocytes. This immunofluorescent SC analysis enables accurate meiotic prophase substaging and the identification of asynaptic pachytene spermatocytes. Spermatogenic defects were examined in azoospermic men using immunofluorescent SC and MLH1 analysis. Five males with obstructive azoospermia, 18 males with nonobstructive azoospermia and 11 control males with normal spermatogenesis were recruited for the study. In males with obstructive azoospermia, the fidelity of chromosome pairing (determined by the percentage of cells with gaps [discontinuities]/splits [unpaired chromosome regions] in the SCs, and nonexchange SCs [bivalents with 0 MLH1 foci]) was similar to those in normal males. The recombination frequencies (determined by the mean number of MLH1 foci per cell at the pachytene stage) were significantly reduced in obstructive azoospermia compared to that in controls. In men with nonobstructive azoospermia, a marked heterogeneity in spermatogenesis was found: 45% had a complete absence of meiotic cells; 5% had germ cells arrested at the zygotene stage of meiotic prophase; the rest had impaired fidelity of chromosome synapsis and significantly reduced recombination in pachytene. In addition, significantly more cells were in the leptotene and zygotene meiotic prophase stages in nonobstructive azoospermic patients, compared to controls. Defects in chromosome pairing and decreased recombination during meiotic prophase may have led to spermatogenesis arrest and contributed in part to this unexplained infertility.

Role of Staphylococcus aureus surface adhesins in orthopaedic device infections: are results model-dependent?

Bacterial colonisation of prosthetic material can lead to clinical infection or implant failure, or both, often requiring removal of the device. Adherence of Staphylococcus aureus to bioprosthetic materials is mediated by adhesins belonging to the MSCRAMM (microbial surface components recognising adhesive matrix molecules) family of microbial cell surface proteins. The objective of this study was to compare the virulence of a mutant strain of S. aureus Newman that possesses all three fibrinogen-, fibronectin- and collagen-binding MSCRAMMs (MSCRAMM-positive strain) with that of a mutant strain that lacks all three types of MSCRAMMs (MSCRAMM-negative strain) in a rabbit model of orthopaedic device-related infection. After a hole was drilled into the knee joint of each animal, a group of 10 rabbits was inoculated with the MSCRAMM-positive strain and another group of 10 rabbits received the MSCRAMM-negative strain. A stainless steel screw was then placed into the drilled hole. Two weeks later, the rabbits were killed and serum samples, bone tissue and implants were harvested for bacteriological and histopathological evaluation. No significant difference in infection rates was demonstrated between the two groups. The ability to delineate the role of S. aureus surface adhesins in causing orthopaedic device-related infection could be model-dependent.

Chromosome analysis of spermatozoa extracted from testes of men with non-obstructive azoospermia

Infertile men with azoospermia now have the possibility of fathering children by testicular sperm extraction combined with intracytoplasmic sperm injection. However, there are concerns about the risk of chromosomal abnormalities in their spermatozoa. We have studied aneuploidy frequencies for chromosomes 13, 21, X and Y by multicolour fluorescence in-situ hybridization (FISH) in testicular spermatozoa extracted from three men with non-obstructive azoospermia. The men were 34-37 years of age and had normal follicle-stimulating hormone (FSH) concentrations and normal 46,XY somatic karyotypes. A total of 3324 spermatozoa was analysed. The infertile patients had an elevated frequency of disomy for chromosomes 13, 21, XY disomy compared to controls but none of these reached statistical significance. Also there was no significant difference in the sex ratio or the frequency of diploidy in azoospermic patients compared to normal control donors. This first report on chromosomal aneuploidy in spermatozoa extracted from testes of patients with non-obstructive azoospermia suggests that some azoospermic men do not have a substantially increased risk of chromosomally abnormal spermatozoa.

Increased risk of craniosynostosis with higher antenatal maternal altitude

BACKGROUND

During the 1980s, the Colorado Department of Health received reports from several high-altitude communities of clusters of the malformation craniosynostosis. In a population-based, case-control study, we examined the association between overall and trimester-specific maternal antenatal altitude exposure and the occurrence of infant craniosynostosis.

METHODS

We identified case children through a statewide registry and randomly sampled control children from birth records. By telephone interview, each mother provided data on the locations of all antenatal residences and places of employment as well as other factors. Staff mapped all locations and abstracted the corresponding altitudes.

RESULTS

The odds ratio (OR) of any synostosis for a time-weighted mean antenatal altitude of > or = 2000 metres (high altitude) versus < 2000 metres (low altitude) was 1.4 (lower bound of the one-sided 95% test-based confidence interval (CI): 0.9). The OR was elevated in smokers but not in non-smokers. As compared to non-smokers, the OR of any synostosis for high-altitude smokers was 4.6 (lower bound of the 95% one-sided exact CI: 1.7). Particularly elevated were the corresponding OR of coronal (18.1, 4.4) and metopic synostosis (16.3, 2.8), and OR for high-altitude exposure during the second trimester (any synostosis: 6.4, 1.99; coronal: 28.6, 6.1; metopic: 26.7, 4.1).

CONCLUSIONS

Antenatal maternal high-altitude exposure and smoking are associated with increased risk of infant craniosynostosis, perhaps through generation of intermittent hypoxaemia.

Cardiovascular effects of marihuana in man

Twenty-eight subjects, matched by sex and Cannabis experience, received by controlled inhalation under single- and double-blind conditions 600 mg marihuana placebo and marihuana. Forearm, venous and arterial pressures, forearm blood flow, and heart rate were recorded while supine. Derived functions such as "dp/dt", regional arterial resistance, and venous compliance were calculated from these variables. (1) Placebo produced no intoxication or consistent physiological responses. (2) Marihuana produced intoxication in all Cannabis-experienced and half the non-experienced subjects. (3) Cardiovascular responses occurred in response to marihuana in the absence of intoxication, indicating that they were not psychogenically mediated. (4) Inhibition of vagal tone may contribute to the tachycardia seen with marihuana. (5) Reflexly mediated sympathetic responses may be muted in the presence of marihuana.

Synchronous marine pelagic regime shifts in the Northern Hemisphere

Regime shifts are characterized by sudden, substantial and temporally persistent changes in the state of an ecosystem. They involve major biological modifications and often have important implications for exploited living resources. In this study, we examine whether regime shifts observed in 11 marine systems from two oceans and three regional seas in the Northern Hemisphere (NH) are synchronous, applying the same methodology to all. We primarily infer marine pelagic regime shifts from abrupt shifts in zooplankton assemblages, with the exception of the East Pacific where ecosystem changes are inferred from fish. Our analyses provide evidence for quasi-synchronicity of marine pelagic regime shifts both within and between ocean basins, although these shifts lie embedded within considerable regional variability at both year-to-year and lower-frequency time scales. In particular, a regime shift was detected in the late 1980s in many studied marine regions, although the exact year of the observed shift varied somewhat from one basin to another. Another regime shift was also identified in the mid- to late 1970s but concerned less marine regions. We subsequently analyse the main biological signals in relation to changes in NH temperature and pressure anomalies. The results suggest that the main factor synchronizing regime shifts on large scales is NH temperature; however, changes in atmospheric circulation also appear important. We propose that this quasi-synchronous shift could represent the variably lagged biological response in each ecosystem to a large-scale, NH change of the climatic system, involving both an increase in NH temperature and a strongly positive phase of the Arctic Oscillation. Further investigation is needed to determine the relative roles of changes in temperature and atmospheric pressure patterns and their resultant teleconnections in synchronizing regime shifts at large scales.

Diagnostic practice and the estimated prevalence of craniosynostosis in Colorado

BACKGROUND

In the late 1980s, evidence of an epidemic of craniosynostosis in Colorado included reports of clusters from selected high-altitude communities and an investigation showing the high and rapidly rising rates of surgically corrected synostosis. Some evidence suggested that local diagnostic practice could account for the epidemic.

OBJECTIVE

To determine the contributions of any excess rates of disease occurrence, surgery-based ascertainment, and diagnosis to the reported epidemic.

DESIGN

Population-based birth prevalence study with diagnostic evaluation.

SETTING

The Colorado Department of Health, April 15, 1986, to July 14, 1989.

PATIENTS OR OTHER PARTICIPANTS

Children in the Craniosynostosis Registry or state birth record files.

MAIN OUTCOME MEASURES

Birth prevalence was estimated from registry and birth record data; case classification by suture type and malformation patterns were determined by review of radiographs and medical records.

RESULTS

The period birth prevalence of radiographically confirmed nonsyndromic synostosis was 14.1 per 10,000 live births. Of a total of 605 children, 307 (51%) had definite radiographic evidence of synostosis, for which the intrarater reliability was good (except for the coronal suture on plain films) and the interrater reliability was fair or good (except for the metopic suture on plain films). Between the first and third years, case reports fell from 347 to 103.

CONCLUSIONS

Diagnostic criteria strongly influenced the rate of synostosis. The rate of radiographically confirmed synostosis was within the range of published estimates. Low diagnostic thresholds, which changed over time, created the semblance of a severe statewide epidemic and may have obscured excess rates of disease at high altitude.

National Neurofibromatosis Foundation International Database

The National Neurofibromatosis Foundation International Database is a system for collecting comprehensive information on the clinical manifestations and natural history of neurofibromatosis. Data are entered into personal computers at participating centres and are pooled at the Central Database and coordinating centre in Vancouver, Canada. The system includes special mechanisms to assure consistency among centres and to maintain patient confidentiality. The database is designed to foster collaborative clinical and molecular genetic research in many aspects of neurofibromatosis.