Modeling the Effects of Future Hydroclimatic Conditions on Microbial Water Quality and Management Practices in Two Agricultural Watersheds

Anticipated future hydroclimatic changes are expected to alter the transport and survival of fecally-sourced waterborne pathogens, presenting an increased risk of recreational water quality impairments. Managing future risk requires an understanding of interactions between fecal sources, hydroclimatic conditions and best management practices (BMPs) at spatial scales relevant to decision makers. In this study we used the Hydrologic Simulation Program FORTRAN to quantify potential fecal coliform (FC - an indicator of the potential presence of pathogens) responses to a range of mid-century climate scenarios and assess different BMP scenarios (based on reduction factors) for reducing the risk of water quality impairment in two, small agricultural watersheds - the Chippewa watershed in Minnesota, and the Tye watershed in Virginia. In each watershed, simulations show a wide range of FC responses, driven largely by variability in projected future precipitation. Wetter future conditions, which drive more transport from non-point sources (e.g. manure application, livestock grazing), show increases in FC loads. Loads typically decrease under drier futures; however, higher mean FC concentrations and more recreational water quality criteria exceedances occur, likely caused by reduced flow during low-flow periods. Median changes across the ensemble generally show increases in FC load. BMPs that focus on key fecal sources (e.g., runoff from pasture, livestock defecation in streams) within a watershed can mitigate the effects of hydroclimatic change on FC loads. However, more extensive BMP implementation or improved BMP efficiency (i.e., higher FC reductions) may be needed to fully offset increases in FC load and meet water quality goals, such as total maximum daily loads and recreational water quality standards. Strategies for managing climate risk should be flexible and to the extent possible include resilient BMPs that function as designed under a range of future conditions.

Differential expression of the neu transgene in murine mammary tissues

The mammary glands of control FVB and mice with MTV-LTR promoted transgenes were stained using immunohistochemistry to detect neu expression. Neu expression in the terminal end buds of developing mammary glands and during early pregnancy in FVB mice was confirmed by in situ hybridization. Neu was expressed in all tumors from mice with the neu transgene but not in tumors expressing transforming growth factor alpha (TGF alpha) or polyoma virus middle T (PyV-MT). Neu was also expressed sporadically in non-neoplastic mammary cells of transgenic neu mice. However, most mammary cells expressing neu were dysplastic. The differential expression of the neu transgene has important implications for the interpretation of transgenic biology.

HIV type 2 intergroup recombinant identified in Cameroon

A unique HIV-2 intergroup recombinant strain was identified in Cameroon. The virus, CM-03-510-03, was amplified from blood collected from a 47-year-old female patient in Douala, Cameroon in 2003 who was seroreactive for HIV-2. A near full-length genome 9089 nucleotides in length was amplified from proviral DNA. The genome for CM-03-510-03 is composed of segments of HIV-2 groups A and B with four recombination break-points and has open reading frames for all the structural and regulatory genes. A comparison of CM-03-510-03 to the only previously reported HIV-2 intergroup recombinant shows that the two strains share one recombination breakpoint but are otherwise distinct from each other. Similar to HIV-1, HIV-2 intergroup recombination is an indication that coinfection with more than one strain has occurred in individuals and is a mechanism that increases strain genetic diversity.

HIV global surveillance: foundation for retroviral discovery and assay development

The high level of HIV genetic diversity has important implications for screening, diagnostic testing and patient monitoring. Continued diversification and global redistribution of HIV groups, subtypes and recombinants make it imperative that serological and molecular assays be designed and evaluated to ensure reliable performance on all HIV infections. Recognizing the importance of this issue, we initiated a comprehensive program to monitor global diversification of HIV, search for newly emerging variants, assemble large-volume panels of genetically and geographically diverse strains, and develop strategies to determine the impact of HIV diversity on assays used for detecting and monitoring HIV infection. Efforts to identify and characterize rare and emerging HIV strains have lead to the identification of HIV-1 group O, group N, and dual infections of groups M and O. A panel of plasma specimens was established that includes specimens collected from 12 countries in Africa, Asia, Europe, and South America; the panel comprises infections due to HIV-1 group M subtypes A, B, C, D, F, and G, as well as CRF01, CRF02, and unique recombinant forms, group N, and group O. Serological and molecular characterization of this unique panel has provided vital sequence data to support assay development and an invaluable source of well-defined specimens to evaluate and compare assay performance. The ability to address the challenge posed by ongoing evolution of HIV and the emergence of new variants requires continued surveillance of global HIV strain diversity, a sound scientific foundation for assay development, and suitable panels to evaluate and validate assay performance.

Lenalidomide and bortezomib induce osteoclast cytotoxicity and decrease BAFF secretion in osteoclasts in human multiple myeloma: Clinical implications

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Background: Myeloma bone disease is caused by an enhanced osteoclast (OCL) activation, leading to osteolytic bone lesions. OCL have recently been reported to produce abundant B-cell activating factor (BAFF) in the bone marrow microenvironment that is important for myeloma cell growth and survival (Blood 106, 1021–30, 2005; ASH2005, #627). The proteasome inhibitor bortezomib (PS341, Velcade) has potent anti-myeloma activity with impressive clinical responses. A recent study indicated that bortezomib has inhibitory effects on OCL (ASH 2005, #2488). Lenalidomide (CC-5013, Revlimid) is an immunomodulatory derivative of thalidomide that has shown promising anti-myeloma effects in patients with relapsed or refractory multiple myeloma (MM) (ASH 2005, #6 & #1565). However, the effect of lenalidomide on human OCL lineage is unknown. Therefore, the aim of this study is to investigate the effect of lenalidomide and bortezomib on human OCL. Methods: OCL formation from healthy donors and MM patients were stimulated with RANKL (50ng/ml) and GM-CSF (10ng/ml) in 20% FBS/RPMI. Cells were incubated with lenalidomide 2μM or bortezomib 2nM, alone and in combination, for two weeks followed by [3H]thymidine uptake assay to measure growth inhibition of OCL. Similar experiments were also performed in cocultures of CD138-purified cells from MM patients with OCL, in the presence or absence of lenalidomide and bortezomib. In addition, ELISA was performed to measure cytokine release of BAFF produced by OCL in these cultures. Results: OCL growth was decreased by lenalidomide (n=6) (median 49.2%, range 20–62.5%; coculture: 53% and 35%) as well as bortezomib (96 and 49%; coculture 63 and 59%) and by the combination of both drugs (95 and 55%; coculture 42 and 44%). BAFF secretion was dramatically decreased in cultures treated with lenalidomide 2μM (n=3) (median 72%, range 61–75.9%). Conclusions: These results indicate that lenalidomide and bortezomib inhibit OCL growth and survival. Importantly, lenalidomide and bortezomib also block growth and survival of MM cells cocultured with OCL, suggesting that lenalidomide may inhibit OCL growth and survival through inhibition of BAFF and may prevent development of osteolytic lesions in MM.

No significant financial relationships to disclose.

HIV-1 Group N: evidence of ongoing transmission in Cameroon

An HIV-1 group N infection, 02CM-DJO0135, was identified among specimens collected in 2002 at the D'Joungolo Hospital, Yaoundé, Cameroon. Sequences were obtained from viral RNA extracted from plasma for regions of LTR-gag, pol-vif, and env. The virus amplified from the specimen is closely related to a previously reported group N virus, 02CM-DJO0131, that was also collected at this hospital in 2002. Although the viral sequences for the two isolates differ, their close relationship suggests that the two specimens are linked. No patient histories are available for 02CM-DJO0131 and 02CM-DJO0135; the specimens could have been drawn from a husband/wife, mother/child, or a single individual. However, differences in seroreactivity indicate that it is unlikely that the specimens were drawn from the same patient. This report documents the second case that suggests linkage between group N-infected individuals and indicates that there is ongoing transmission of HIV-1 group N in Cameroon.

Identification of HIV type 1 group N infections in a husband and wife in Cameroon: viral genome sequences provide evidence for horizontal transmission

HIV-1 is classified into three groups, M (major), N (non-M non-O), and O (outlier); each group arose from a separate transmission of SIVcpz into humans. HIV-1 group N was recently discovered and infections with this virus are rare with only eight documented cases. All group N infections have been found in Cameroon and there is no evidence of direct linkage between the infected patients. We report here the identification of HIV-1 group N infections in a husband and wife. The group N infection in the husband, 1131-03, was identified first based on seroreactivity in peptide EIAs and confirmed by PCR amplification of group N viral sequences. Subsequently the wife, 1015-04, was evaluated and confirmed to also be infected with a group N virus. Near full-length viral genomes were amplified and sequenced from each patient's specimen. The low level of diversity between the two viral sequences provides evidence of horizontal transmission of group N from one spouse to the other. Patient 1131-03 was receiving antiviral therapy consisting of reverse transcriptase inhibitors; the treatment appears effective for suppression of group N viral replication based on apparently low viral load in plasma specimens collected from the patient and the absence of drug resistance mutations in RT sequences amplified from 1131-03. This report brings to 10 the number of group N infections identified and to 5 the number of group N genomes sequenced. Although group N infections continue to be rare, group N is a pathogenic virus and its prevalence needs to be monitored.

HIV infections in northwestern Cameroon: identification of HIV type 1 group O and dual HIV type 1 group M and group O infections

HIV-1 strain diversity was examined in a study population that consisted of hospital and clinic patients from seven cities and villages located in the northwestern regions of Cameroon. Specimens were screened using a serological algorithm designed to identify HIV-1 group M, N, and O, and SIVcpz-like infections followed by RT-PCR amplification to characterize the infecting virus. The results show that the HIV epidemic in northwest Cameroon is dominated by HIV-1 group M CRF02_AG infections (57%). Additional group M subtypes present include A, D, F2, G, and CRF01_AE. Based on discordant subtype classification between gag and env sequences, a high percentage (23%) of viral strains appear to be unique intersubtype recombinants with the majority (88%) involving recombination with CRF02_AG. Group O prevalence is low accounting for only 0.4% of HIV infections. However, group O strain diversity is high; isolates from clades I, IV, and V, as well as unclassified and recombinant strains, were found. Three dual infections by HIV-1 group M and group O were identified and characterized. In two specimens, both group M and O sequences were amplified in gag, pol, and env suggesting the presence of both viruses. Analysis of the third specimen shows the presence of a group O virus and an intergroup M/O recombinant virus. Finally, no infections due to HIV-1 group N or SIVcpz-like strains were found in the study population.

Identification and genomic sequence of an HIV type 1 group N isolate from Cameroon

HIV-infected plasma specimens, collected in Cameroon between 1999 and 2002, were screened for HIV-1 group N and SIVcpz infections using a serological screening algorithm based on immunoassays with antigens derived from HIV-1 group M, N, and O, and SIVcpz strains. Specimens with reactivity to group N and SIVcpz antigens were characterized by RT-PCR and sequence analysis to identify the infecting virus. Although several specimens were serotyped as potential group N or SIVcpz infections, only one group N infection was confirmed. The specimen, 02CM-DJO0131, was collected in 2002 from a hospital patient at the D'Joungolo Hospital, Yaoundé. The virus genome was amplified as seven overlapping fragments comprising 8938 nucleotides. Phylogenetic analysis shows that 02CM-DJO0131 branches with group N sequences. With this study, three near full-length sequences are now available for group N. While we confirm the presence of group N in the Cameroonian population, group N infections continue to be rare and difficult to identify.

A phase I study of vitamin E, 5-fluorouracil and leucovorin for advanced malignancies

Six patients with incurable malignancies were originally treated with vitamin E, 3200 IU/day for fourteen days, followed by the same dose of vitamin E daily plus LCV (20 mg/m2 i.v. bolus daily x 5) with 5FU (425 mg/m2 i.v. bolus immediately following LCV). The same schedule of LCV and 5FU was repeated 4 weeks later, then every 5 weeks indefinitely. When 3 of the first 6 had grade 3/4 toxicity, six more patients were treated on the identical drugs and schedule. Seven of twelve total patients had one or more grade 3/4 toxicities. Neutropenia, abdominal pain, and diarrhea were most common. No patient had a documented response, though seven patients did have stable disease. Though the combination of vitamin E and chemotherapy was toxic, this trial demonstrated maximal therapeutic doses of vitamin E can be combined with standard 5FU and LCV, without significantly increasing the side effects of the chemotherapy itself.

The lactoperoxidase system functions in bacterial clearance of airways

Airway mucus is a complex mixture of secretory products that provides a multifaceted defense against pulmonary infection. Mucus contains antimicrobial peptides (e.g., defensins) and enzymes (e.g., lysozyme) although the contribution of these to airway sterility has not been tested in vivo. We have previously shown that an enzymatically active, heme-containing peroxidase comprises 1% of the soluble protein in sheep airway secretions, and it has been hypothesized that this airway peroxidase may function as a biocidal system. In this study, we show that sheep airway peroxidase is identical to milk lactoperoxidase (LPO) and that sheep airway secretions contain thiocyanate (SCN(-)) at concentrations necessary and sufficient for a functional peroxidase system that can protect against infection. We also show that airway LPO, like milk LPO, produces the biocidal compound hypothiocyanite (OSCN(-)) in vitro. Finally, we show that in vivo inhibition of airway LPO in sheep leads to a significant decrease in bacterial clearance from the airways. The data suggest that the LPO system is a major contributor to airway defenses. This discovery may have significant implications for chronic airway colonization seen in respiratory diseases such as cystic fibrosis.

Concurrence of Pendred syndrome, autoimmune thyroiditis, and simple goiter in one family

Pendred syndrome is the autosomal recessively transmitted association of familial goiter and congenital deafness. There is no specific biochemical marker of this disease, and the diagnosis depends upon the demonstration of the triad of congenital sensorineural hearing loss, goiter, and abnormal perchlorate discharge test. Pendred syndrome is caused by mutations within the putative ion transporter gene (PDS gene), located on chromosome 7q. A wide variation in the clinical presentation of this condition, and its well documented phenotypic overlap with other thyroid disorders (such as Hashimoto's thyroiditis), can lead to diagnostic difficulties. The potential for misdiagnosis increases when these disorders occur coincidentally in the same family. We describe a kindred in which Pendred syndrome, autoimmune thyroiditis, and simple goiter coexisted, to highlight these diagnostic pitfalls and to illustrate the use of mutational analysis in resolving diagnostic confusion.

Prevalence, age of onset, and natural history of thyroid disease in Pendred syndrome

BACKGROUND

We have sought to establish the prevalence of goitre within a Pendred syndrome (PS) cohort and to document the course of thyroid disease in this patient group. As part of a genetic study of PS we have assessed 57 subjects by perchlorate discharge test and in 52 (M 21, F 31, age range 9-54 years) a discharge of radioiodide of >10% was observed.

RESULTS

Goitre was present in 43 (83%) of the cohort (28 F, 15 M), generally developing after the age of 10 years, 56% remained euthyroid (age range 9-37 years), and 19 patients (44%) had objective evidence of hypothyroidism, all of whom had goitre.

CONCLUSIONS

In summary, thyroid dysfunction in PS is variable and inclusion of goitre as a diagnostic requirement will maintain significant underascertainment. The recent identification of the genetic defect underlying PS is likely to provide an important diagnostic aid in the identification of this disorder and this communication should assist clinicians in identifying deaf patients who ought to be considered for this investigation.

Regulation of Fas antibody induced neutrophil apoptosis is both caspase and mitochondrial dependent

Resolution of neutrophil mediated inflammation is achieved, in part, through induction of neutrophil apoptosis. This constitutively expressed programme can be delayed by inflammatory mediators and induced by ligation of the Fas receptor. However, functional activation of the neutrophil results in resistance to Fas signalled death. We evaluated the effects of Fas antibody engagement on caspase activation and mitochondrial permeability, and the impact of co-stimulation by lipopolysaccharide (LPS) or granulocyte macrophage-colony stimulating factor (GM-CSF) on these events. Fas engagement by an agonistic anti-Fas antibody resulted in enhanced caspase 3 and 8 activity and increased mitochondrial permeability. Studies with pharmacological inhibitors of caspase activity showed that activation of caspase 8 occurred before, and activation of caspase 3 occurred after mitochondrial disruption. The mitochondrial stabilising agent bongkrekic acid also inhibited caspase activation and apoptosis. LPS, GM-CSF and increased glutathione stabilised the mitochondria and inhibited caspase 3. Caspase 8 activity was also inhibited by co-stimulation through a mechanism independent of mitochondrial stabilisation. Glutathione directly inhibited caspase 3 and 8 activity. We conclude inhibition of Fas antibody induced apoptosis by inflammatory proteins is associated with augmented mitochondrial stability and reduced caspase 3 activity that may be glutathione mediated.

Alström syndrome. Report of 22 cases and literature review

OBJECTIVE

The authors report 22 cases of Alström syndrome (AS), which is the largest series to date. Only 37 cases have been reported in the world literature since 1959. The authors review the clinical features and compare these with the overlapping condition of Bardet-Biedl syndrome. Their aim is to clarify the AS phenotype and to increase awareness of the early features.

DESIGN

A retrospective case series.

PARTICIPANTS

All patients (22) with a diagnosis of AS admitted to the authors' hospital in the past 10 years were included in this review.

INTERVENTION

This is principally a review of ocular features, but other features are recorded and discussed.

MAIN OUTCOME MEASURES

Features noted included age at onset of visual symptoms, presence of photophobia, visual acuity, and electroretinogram findings. Nonocular features recorded included cardiac status, weight and height, hearing, and presence of diabetes mellitus.

RESULTS

Cardiomyopathy presenting in infancy has only been recognized recently to be a feature of AS. Of the authors' cases, 18 of 22 had infantile cardiomyopathy. In the authors' tertiary referral institution, there is an ascertainment bias toward younger patients and especially those with pathology that is other than ocular pathology. In addition, AS is difficult to recognize in childhood without the development of infantile cardiomyopathy. Alström syndrome often is not recognized until diabetes mellitus develops in the second or third decade. Initially, a diagnosis of cone-rod dystrophy, achromatopsia, Leber's congenital amaurosis, or Bardet-Biedl syndrome may be made. In AS, there is a severe infantile retinal dystrophy. The electroretinogram is absent or attenuated with better preserved rod than cone function. The retinal dystrophy is progressive with the patient's visual acuity of 6/60 or less by 10 years of age and no light perception by 20 years of age.

CONCLUSIONS

A diagnosis of AS should be considered in infantile cone and rod retinal dystrophy, particularly if the weight is above the 90th percentile (16 of 18 cases) or if there is an infantile cardiomyopathy (18 of 22 cases).

Molecular analysis of the PDS gene in Pendred syndrome

Pendred syndrome is an autosomal recessive disorder characterized by the association between sensorineural hearing loss and thyroid swelling or goitre and is likely to be the most common form of syndromic deafness. Within the thyroid gland of affected individuals, iodide is incompletely organified with variable effects upon thyroid hormone biosynthesis, whilst the molecular basis of the hearing loss is unknown. The PDS gene has been identified by positional cloning of chromosome 7q31, within the Pendred syndrome critical linkage interval and encodes for a putative ion transporter called pendrin. We have investigated a cohort of 56 kindreds, all with features suggestive of a diagnosis of Pendred syndrome. Molecular analysis of the PDS gene identified 47 of the 60 (78%) mutant alleles in 31 families (includes three homozygous consanguineous kindreds and one extended family segregating three mutant alleles). Moreover, four recurrent mutations accounted for 35 (74%) of PDS disease chromosomes detected and haplotype analysis would favour common founders rather than mutational hotspots within the PDS gene. Whilst these findings demonstrate molecular heterogeneity for PDS mutations associated with Pendred syndrome, this study would support the use of molecular analysis of the PDS gene in the assessment of families with congenital hearing loss.

Recurrence risks in offspring of adults with major heart defects: results from first cohort of British collaborative study

BACKGROUND

Congenital heart defects are generally assumed to have a multifactorial aetiology. We have tested this hypothesis by studying adults with heart defects and their families.

METHODS

We identified 1094 patients who survived surgery for major cardiac defects before 1970. We chose individuals with disturbance of situs or segmental connection, with atrioventricular septal defect or with tetralogy of Fallot. After exclusion and non-participation, 727 individuals were traced. Each was visited by an investigator and completed a detailed questionnaire. If possible, all "normal" offspring were examined by a paediatric cardiologist.

FINDINGS

The 727 individuals had 393 live offspring. There were 71 miscarriages and five terminated pregnancies. Overall, we found recurrent heart defects in 16 liveborn offspring--a recurrence risk of 4.1%. This result differed significantly from sibling risk (2.1%; p=0.021). More congenital heart defects occurred in the offspring of affected women than in those of affected men (p=0.047); when all malformations (cardiac and non-cardiac) in the offspring were taken into account the excess was more significant (p=0.032). We found an excess of miscarriages in the offspring of affected women (p=0.001). In tetralogy of Fallot, heart defects occurred in seven (3.1%) of 223 offspring, 12 (2.2%) of 539 siblings, five (0.3%) of 1575 second-degree relatives, and eight (0.3%) of 2728 third-degree relatives.

INTERPRETATION

Our findings do not support a polygenic basis for all heart defects. Atrioventricular septal defect seems to be a single-gene defect and tetralogy of Fallot a polygenic disorder with a small number of interacting genes. Our data suggest that isolated transposition of the great arteries is a sporadic defect.

Pendred syndrome--100 years of underascertainment?

Pendred syndrome is an autosomal recessive condition classically characterized by deafness and goitre. Since both cochlear and thyroid pathology are required to secure the diagnosis, it is unclear whether the condition might present without the classical features. The perchlorate discharge test, the gold-standard investigation for Pendred syndrome, is non-specific, and in the absence of alternative means of confirming the diagnosis, its sensitivity is unknown. We used the recent mapping of the gene to chromosome 7q to identify pedigrees with a likely diagnosis of Pendred syndrome, and assessed the prevalence of clinical parameters of disease in affected patients. Thirty-six familial cases showed co-segregation between disease and the Pendred syndrome locus on chromosome 7q. Clinical and investigative findings were compared in index cases (n = 18) vs. affected siblings (n = 18). The overall prevalence of goitre was 73%, higher in index cases (94%) than in siblings (56%), many of whom had not previously been considered to have the condition. One perchlorate discharge test was false-negative (2.9%). Radiological malformations of the cochlea were identified in 86% of cases. Securing a diagnosis of Pendred syndrome may be difficult, especially in the single case. The perchlorate discharge test, although valuable, is difficult to undertake in the younger patient, and radiology may assist in diagnosing such patients.

Abnormal audiograms and elevated acoustic reflex thresholds in obligate carriers of autosomal recessive non-syndromic hearing loss

Pure-tone audiograms and acoustic reflex thresholds were obtained in 24 presumed obligate carriers of autosomal recessive non-syndromic hearing loss and 30 sex and age appropriate control subjects, with a view to evaluating the prevalence of abnormalities on these tests in the two groups, and a possible link between the findings on the two tests, which may help to localize threshold deficits and/or abnormal configurations to different sections of the reflex arc. Six (25%) of the carriers and one control subject had abnormal audiograms, inferred to be of genetic aetiology through careful exclusion of environmental risk factors. Four additional carriers had acoustic reflex threshold abnormalities. None of the carriers had an abnormality on both tests. The audiometric configurations and acoustic reflex patterns of abnormality were diverse, and may be a reflection of the genetic heterogeneity in ARNSHL.

Pendred syndrome: evidence for genetic homogeneity and further refinement of linkage

Pendred syndrome is the association between congenital sensorineural deafness and goitre. The disorder is characterised by the incomplete discharge of radioiodide from a primed thyroid following perchlorate challenge. However, the molecular basis of the association between hearing loss and a defect in organification of iodide remains unclear. Pendred syndrome is inherited as an autosomal recessive trait and has recently been mapped to 7q31 coincident with the non-syndromic deafness locus DFNB4. To define the critical linkage interval for Pendred syndrome we have studied five kindreds, each with members affected by Pendred syndrome. All families support linkage to the chromosome 7 region, defined by the microsatellite markers D7S501-D7S523. Detailed haplotype analysis refines the Pendred syndrome linkage interval to a region flanked by the marker loci D7S501 and D7S525, separated by a genetic distance estimated to be 2.5 cM. As potential candidate genes have as yet not been mapped to this interval, these data will contribute to a positional cloning approach for the identification of the Pendred syndrome gene.

Dips on Békésy or audioscan fail to identify carriers of autosomal recessive non-syndromic hearing loss

Békésy and audioscan sweep audiometry tests were carried out in 24 presumed obligate carriers of autosomal recessive non-syndromic hearing loss and 30 sex and age appropriate controls, with a view to defining the most expedient criteria for dips on either test in respect of possible carrier detection. On Békésy, dips with a minimum depth of 22.5 dB generated the greatest difference between carriers and non-carriers, while on audioscan, the criterion of a minimum dip depth of 15 dB provided the best discriminant. Using these criteria, the prevalence of dips was also evaluated in 8 unaffected siblings and 24 age appropriate control subjects. The findings both in the adult and the paediatric groups do not support the hypothesis that the presence of dips, either on Békésy or audioscan, is linked to the carrier state in ARNSHL.

Thyroid peroxidase: evidence for disease gene exclusion in Pendred's syndrome

OBJECTIVE

Pendred's syndrome is an association between congenital neurosensory deafness and goitre with abnormal discharge of iodide following perchlorate challenge, indicating a defect of iodide organification. Although Pendred's syndrome may cause up to 7.5% of all cases of congenital deafness, the molecular basis of the association between the hearing loss and the thyroid organification defect remains unknown. We chose to investigate the role of the thyroid peroxidase (TPO) gene as the genetic defect in Pendred's syndrome.

DESIGN

A highly informative variable number tandem repeat (VNTR), located 1.5 kb downstream of exon 10 of the TPO gene, was used to search for genetic linkage in multiple sibships affected by Pendred's syndrome.

PATIENTS

Seven kindreds were recruited from the UK, each with at least two affected members. We have also examined a large inbred Israeli family with two affected offspring and five unaffected children.

MEASUREMENTS

Individuals were assigned affected status based on the characteristic clinical features of Pendred's syndrome, namely the presence of congenital sensorineural hearing loss and the appearance in early life of a goitre. Additionally, at least one affected member from each sibship had a characteristic positive perchlorate discharge test (Morgans & Trotter, 1958). PCR amplification of genomic DNA at the TPO VNTR allowed assignment of genotypes to each individual and the calculation of a two-point LOD score.

RESULTS

In six of the nine sibships analysed we found obligatory recombination between TPO and Pendred's syndrome. Non-complementation observed in affected parents with an affected offspring excluded TPO in an affected sibship with genotype sharing and supports a hypothesis of genetic homogeneity for Pendred's syndrome. In two sibships, mutation of the TPO gene as the cause of Pendred's syndrome could not be excluded.

CONCLUSIONS

These data suggest that defects at the thyroid peroxidase locus on chromosome 2 are not the major cause of Pendred's syndrome.

Pendred syndrome (goitre and sensorineural hearing loss) maps to chromosome 7 in the region containing the nonsyndromic deafness gene DFNB4

Inherited causes account for about 50% of individuals presenting with childhood (prelingual) hearing loss, of which 70% are due to mutation in numerous single genes which impair auditory function alone (non-syndromic). The remainder are associated with other developmental anomalies termed syndromic deafness. Genes responsible for syndromic forms of hearing loss include the COL4A5 gene in Alport syndrome and the PAX3 and MITF genes in Waardenburg syndrome. Pendred syndrome is an autosomal recessive disorder associated with developmental abnormalities of the cochlea, sensorineural hearing loss and diffuse thyroid enlargement (goitre). Pendred syndrome is the most common syndromal form of deafness, yet the primary defect remains unknown. We have established a panel of 12 families with two or more affected individuals and used them to search for the location of the Pendred gene by linkage analysis. We excluded localization to four previously mapped nonsyndromic deafness loci but obtained conclusive evidence for linkage of the Pendred syndrome gene to microsatellite markers on chromosome 7q31 (D7S495 Zmax 7.32, Qmax = 0). This region contains a gene, DFNBL, for autosomal recessive non-syndromic sensorineural hearing loss. Multipoint analysis indicates that DFNB4 and Pendred syndrome co-localize to the same 5.5 centiMorgan (cM) interval flanked by D7S501 and D7S523. These data raise the possibility that Pendred syndrome is either allelic with DFNB4 or may represent an inherited contiguous gene disorder, not clinically manifest in the heterozygote.

Concordance and recessive inheritance of Leber congenital amaurosis

Pedigrees were obtained on 43 patients with confirmed Leber congenital amaurosis, a rare form of blindness caused by congenital dysfunction of the retina. All of the pedigrees were consistent with autosomal recessive inheritance and the segregation frequency using classical segregation analysis was 0.24 +/- 0.07. Six of the 7 affected sib pairs were concordant in regards to systemic abnormalities. Despite previous reports that Leber congenital amaurosis can be inherited either as an autosomal dominant or recessive condition, our findings support only an autosomal recessive inheritance of this disorder.

Linkage analysis of infantile pyloric stenosis and markers from chromosome 9q11-q33: no evidence for a major gene in this candidate region

A genetic component in the aetiology of infantile pyloric stenosis (PS) is well established. Segregation analysis is compatible with a multifactorial sex modified threshold model of inheritance but a major gene of low penetrance has not been excluded. PS has been reported to occur in 57% (four of seven) of cases with duplication of chromosome 9q11-q33. Twenty families with PS were studied using genetic markers at loci D9S55, D9S111, D9S15, D9S12, D9S56, D9S59, and ASS from this region of chromosome 9. Pairwise lod scores of -2 were obtained with all these markers at recombination fractions greater or equal to 0.04 under both autosomal dominant and autosomal recessive models of inheritance. This provides evidence against the existence of a major locus predisposing to PS within chromosome 9q11-q33.

The aging population. A critical issue in medicine for the 21st century

One critical issue facing medical science concerns the aging population. The number of individuals 65 years and older has increased during the past decade and likely will double by the year 2030, when the elderly will represent nearly 20% of the total population. This dramatic increase has numerous ramifications; health care is of utmost importance. Inherent in meeting the medical needs of these individuals is a fundamental understanding of the effects of aging on the functional integrity of numerous organ systems. In recognition of this problem, the Department of Pharmacology and Therapeutics at the University of South Florida College of Medicine has initiated a major effort focused on age-related research. The objectives are to elucidate fundamental biochemical, physiological, and pharmacological alterations that occur as a consequence of normal aging and to investigate the role of these perturbations on the manifestations of disease. Information gained from such studies will provide a rational approach in developing therapeutic strategies for the treatment of diseases affecting older citizens. This article presents a brief overview of four areas of research currently being pursued. These include aging and brain function, age-related alterations in drug metabolism, aging and smooth muscle function, and the effects of aging on the immune system.

Treatment of arteriovenous malformations of the brain with combined embolization and stereotactic radiosurgery: results after 1 and 2 years

Seven patients with large arteriovenous malformations (AVMs) of the brain were selected for combined therapy with particulate embolization, followed by radiosurgery of the residual nidus. The goal of embolization was to reduce the patient nidus to a size that facilitated successful stereotactic radiosurgery. Angiograms obtained 1 and 2 years after radiosurgery were evaluated for changes in nidus size, flow rate, and feeding and draining vessels. One year after stereotactic radiosurgery, one AVM was angiographically undetectable. Three other AVMs demonstrated a volume reduction of greater than 50%, in addition to decreased shunt speed and altered angioarchitecture at 1-year follow-up. At 2-year follow-ups, two of seven AVMs were cured, and an additional two of seven had a greater than 98% reduction in nidus volume. Although one patient experienced a transient deficit from embolotherapy, none of our patients suffered a new neurologic deficit or a hemorrhage during the follow-up period. Our data support the efficacy of combined embolotherapy and radiosurgery for definitive therapy of selected large AVMs of the brain.

Follow-up and diagnostic reappraisal of 75 patients with Leber's congenital amaurosis

We reexamined 75 children in whom Leber's congenital amaurosis had been previously diagnosed. On review, 30 of these patients had an ocular or systemic disorder other than Leber's congenital amaurosis. The most common of these revised diagnoses were congenital stationary night blindness, achromatopsia, infantile-onset retinitis pigmentosa, Joubert's syndrome, Zellweger syndrome, and infantile Refsum's disease. Of the 45 patients with Leber's congenital amaurosis, mental retardation occurred in six patients, and visual deterioration in six patients. Leber's congenital amaurosis should only be diagnosed if other known ocular and systemic disorders have been carefully excluded.

Family screening in medullary thyroid carcinoma presenting without a family history

Systematic screening of the families of a series of 39 patients with apparently sporadic medullary thyroid carcinoma detected seven new cases in four families. A negative family history in a patient presenting with medullary thyroid carcinoma is not reliable in excluding familial disease, and family screening should be considered for new patients with medullary thyroid carcinoma.

Risk estimation and screening in families of patients with medullary thyroid carcinoma

Many gene carriers for multiple endocrine neoplasia type 2a (MEN 2a) do not manifest the disease, even into old age. Thus, a negative family history in a patient presenting with medullary thyroid carcinoma does not reliably exclude familial disease. Data are reported for the probability that the MEN 2a gene will either have manifested clinically or be detectable by stimulated calcitonin screening by a given age. These probabilities can be used to calculate individual risks and to guide screening.

The cerebrovascular effects of intraarterial CO2 in quantities required for diagnostic imaging

The recent development of digital subtraction angiography (DSA) has renewed interest in the use of gases, especially carbon dioxide, as contrast agents. Both early physiologic studies and recent clinical reports suggest that arterial CO2-DSA is a safe and useful diagnostic tool in the examination of extremity circulation. The present study examined the neurologic sequelae, pathologic changes, and effects on the blood-brain barrier to intravenous Evans-Blue and horseradish peroxidase of intracarotid CO2, in albino rats. As with other forms of cerebral gas embolization, CO2 produced multifocal ischemic infarctions and disrupted the blood-brain barrier to macromolecular tracers. The site of the barrier lesion is the endothelial cell membrane, although the precise mechanisms of damage remain unknown. Caution must be urged in the use of CO2-DSA to avoid embolization of the central nervous system.

A family study of isolated cleft palate

A family study was based on 245 boy and 329 girl patients treated surgically for non-syndromic cleft palate between 1920 and 1929; 86 and 81 respectively were traced and had had children. These 167 were the probands for the family study and were interviewed in their homes. None was born to a consanguineous marriage. Altogether they had had 384 children of whom 11 had cleft palate (2.9 +/- 0.9%). They had 398 sibs of whom five had cleft palate, 117 grandchildren of whom one was affected, and 517 nephews and nieces of whom one was affected. This is the largest series yet available on which to base an estimate of the risks to children of patients with non-syndromic cleft palate. The risk is probably increased where a parent or sib of the proband is affected and increased to a lesser degree where a second or third degree relative is affected. The family patterns in these and other studies suggest that the aetiology of cleft palate is heterogeneous, with some families showing modified dominant inheritance. This is in contrast to cleft lip (+/- cleft palate) where the data are consistent with a multifactorial threshold model.

A three generation family study of cleft lip with or without cleft palate

A family study of cleft lip, with or without cleft palate, was based on those treated by operation at The Hospital for Sick Children, London, between 1920 and 1939 in order to give information on the proportion affected of children and grandchildren. The probands were those who had survived, were successfully traced, and found to have had at least one child. Care was taken to exclude patients who were traced through a child, whether normal or affected, and not through the usual tracing procedure. Patients with recognised syndromes were also excluded. Because the series was based on patients who had survived and reproduced it was biased in favour of those with milder degrees of the malformation, and against those with any severe associated malformation. The proportion affected of children of probands was 3.15% (+/- 0.56), of sibs 2.79% (+/- 0.52), and of parents 1.18% (+/- 0.37), respectively. The lower proportion of parents affected is attributed to reduced reproductive fitness of patients born two generations ago. The proportion affected of nephews and nieces, aunts and uncles, and grandchildren was 0.47% (+/- 0.18), 0.59% (+/- 0.13), and 0.8% (+/- 0.6) respectively. The proportion affected of first cousins was 0.27% (+/- 0.08). The birth frequency of cleft lip (+/- cleft palate) is estimated to be about 0.1% in England. There were two first cousin and one second cousin marriages among the marriages of the parents. There was no increase of cleft palate among the relatives of the probands. The proportion of sibs affected increased with increasing severity of the malformation in the proband, where the proband was female, and where the proband had an affected parent or already had one affected sib. It was not, however, increased where a more remote relative was affected. The proportion of children affected was not increased when the proband had an affected parent or sib, but few families provided information. The most economical hypothesis to explain the findings is the multifactorial threshold model. The birth frequency of the malformation and the family patterns found make it improbable that one single mutant gene makes a major contribution to the liability to develop the condition.

A family study of craniosynostosis, with probable recognition of a distinct syndrome

A family study was based on 184 consecutive patients who had undergone surgery for craniosynostosis at The Hospital for Sick Children, London, between 1953 and 1976. Of these, 127 were traced and visited and are the probands for this study. Crouzon syndrome was recognised in 16, Apert in 11, Saethre-Chotzen in nine, and Pfeiffer in two. In addition, two probands had Saethre-Chotzen-like facies and bilaterally broad big toes owing to partial or complete duplication of the distal phalanx. This syndrome is distinct from Pfeiffer syndrome, in which the facies more closely resembles that in Crouzon syndrome and in which it is the proximal phalanx of the big toe (and often of the thumb) which is abnormal. It is suggested that this newly recognised syndrome be called after Robinow and Sorauf, who appear to be the first to have described a family with the condition. One proband with coronal stenosis had a mother and brother affected, but no syndrome was recognised in them. Excluding this last case, no non-syndromic proband had an affected parent. The 58 probands with predominantly sagittal synostosis had 106 sibs, none of whom was affected. The 21 probands with predominantly coronal synostosis included one sib pair both affected; the remaining 17 sibs were unaffected. The four probands with predominantly metopic stenosis had 13 unaffected sibs and the four with multiple sutures involved had eight unaffected sibs. One sagittal proband had an unaffected monozygotic twin and another an unaffected dizygotic twin.

Comparison of plasma histamine and cyclic nucleotides after antigen and methacholine inhalation in man

Serial determinations of plasma histamine and cyclic nucleotides (adenosine monophosphate [AMP] and guanosine monophosphate [GMP]) were performed after inhalation of antigen and methacholine in four groups of subjects. In the first group, consisting of six antigen-sensitive subjects exhibiting bronchospasm after inhalation of ragweed or grass antigen, plasma histamine was elevated within 2 min and persisted for 30 min after inhalation of antigen. Peak histamine levels were between 18 to 80 ng/ml. In the second group, consisting of four nonatopic subjects, neither bronchospasm nor histamine was observed, despite inhalation of the same or 10-fold increased concentrations of antigen. In the third group, consisting of six subjects (three atopic and three nonatopic) exhibiting bronchospasm after inhalation of 2.5 to 10 mg of methacholine, sustained increases of histamine began at 1 min and persisted for 60 min after inhalation of methacholine. In the fourth group, seven subjects (two atopic, five nonatopic) without demonstrable bronchospasm despite inhalation of 2.5- to 10-fold increased doses of methacholine, no histamine was detected in the plasma at any time after inhalation of methacholine. Serial measurements of cyclic nucleotides showed no consistent changes in serum levels of cyclic AMP or cyclic GMP following inhalation challenge. We conclude that serum levels of histamine but not cyclic nucleotides change during bronchospasm induced by either antigen or methacholine.

A family study of bladder exstrophy

The families of 102 index patients with bladder exstrophy treated at The Hospital for Sick Children, Great Ormond Street were studied in an attempt to arrive at an empirical risk of recurrence for sibs. Of the 102 patients, 89 had complete exstrophy, eight had partial exstrophy (variant), and five had exstrophy of the cloaca. In all they had 162 sibs, none of whom had bladder exstrophy. The risk to sibs, in this study and from reports by surgeons of sib pairs in their consecutive series, is low and probably less than 1%. There is a suggestion of an increase in central nervous system malformation in sibs as well as in the index patients.

Hypercalcemic hyperparathyroidism in hypophosphatemic rickets

A 25-year-old white woman with sporadic hypophosphatemic rickets presented with a 7 year history of chronic mild hypercalcemia, osteitis fibrosa cystic and hypercalcemic nephropathy. Serum immunoreactive parathyroid hormone was elevated by greater than 100-fold and a 3.5 g parathyroid tumor was found at operation. Survey of the literature reveals that of 9 previous cases in which hypercalcemic hyperparathyroidism occurred in association with hypophosphatemic rickets, only two had classical x-linked familial hypophosphatemic rickets. It appears more than likely that this unusual combination of skeletal diseases represents the chance occurrence of primary hyperparathyroidism in patients with underlying x-linked familial hypophosphatemic rickets rather than a complication of phosphate therapy.