Urinary extracellular vesicles as a source of protein-based biomarkers in feline chronic kidney disease and hypertension

OBJECTIVES

To validate a methodology for isolating feline urinary extracellular vesicles and characterise the urinary extracellular vesicle population and proteome in cats with normal renal function and cats with normotensive or hypertensive chronic kidney disease.

METHODS

Feline urinary extracellular vesicles were isolated using three different methods (precipitation alone, precipitation followed by size exclusion chromatography and ultrafiltration followed by size exclusion chromatography, which were compared via transmission electron microscopy and nanoparticle tracking analysis. Cats with normal renal function (n=9), normotensive chronic kidney disease (n=10) and hypertensive chronic kidney disease (n=9) were identified and urinary extracellular vesicles isolated from patient urine samples via ultrafiltration followed by size exclusion chromatography. Extracellular vesicle size and concentration were determined using nanoparticle tracking analysis, and subsequently underwent proteomic analysis using liquid chromatography with tandem mass spectrometry to identify differences in protein expression between categories.

RESULTS

Urinary extracellular vesicle preparations contained particles of the expected size and morphology, and those obtained by ultrafiltration + size exclusion chromatography had a significantly higher purity (highest particle: protein ratio). The urinary extracellular vesicle proteomes contained extracellular vesicle markers and proteins originating from all nephron segments. Urinary extracellular vesicle concentration and size were unaffected by renal disease or hypertension. There were no differentially expressed proteins detected when comparing urinary extracellular vesicles derived from cats in the healthy category with the combined chronic kidney disease category, but five differentially expressed proteins were identified between the normotensive chronic kidney disease and hypertensive chronic kidney disease categories.

CLINICAL SIGNIFICANCE

Feline urinary extracellular vesicles can be successfully isolated from stored urine samples. Differentially expressed urinary extracellular vesicle proteins were discovered in cats with hypertensive chronic kidney disease, and warrant further investigation into their utility as biomarkers or therapeutic targets.

Hypothalamic Reproductive Endocrine Pulse Generator Activity Independent of Neurokinin B and Dynorphin Signaling

CONTEXT

Kisspeptin-neurokinin B (NKB)-dynorphin neurons are critical regulators of the hypothalamic-pituitary-gonadal axis. NKB and dynorphin are hypothesized to influence the frequency of GnRH pulses, whereas kisspeptin is hypothesized to be a generator of the GnRH pulse. How these neuropeptides interact remains unclear.

OBJECTIVE

To probe the role of NKB in GnRH pulse generation and to determine the interactions between NKB, kisspeptin, and dynorphin in humans and mice with a complete absence of NKB.

DESIGN

Case/control.

SETTING

Academic medical center.

PARTICIPANTS

Members of a consanguineous family bearing biallelic loss-of-function mutations in the gene encoding NKB and NKB-deficient mice.

INTERVENTIONS

Frequent blood sampling to characterize neuroendocrine profile and administration of kisspeptin, GnRH, and naloxone, a nonspecific opioid receptor antagonist used to block dynorphin.

MAIN OUTCOME MEASURES

LH pulse characteristics.

RESULTS

Humans lacking NKB demonstrate slow LH pulse frequency, which can be increased by opioid antagonism. Mice lacking NKB also demonstrate impaired LH secretion, which can be augmented with an identical pharmacologic manipulation. Both mice and humans with NKB deficiency respond to exogenous kisspeptin.

CONCLUSION

The preservation of LH pulses in the absence of NKB and dynorphin signaling suggests that both peptides are dispensable for GnRH pulse generation and kisspeptin responsiveness. However, NKB and dynorphin appear to have opposing roles in the modulation of GnRH pulse frequency.

Microbiological risk assessment for personal care products

Regulatory decisions regarding microbiological safety of cosmetics and personal care products are primarily hazard-based, where the presence of a potential pathogen determines decision-making. This contrasts with the Food industry where it is a commonplace to use a risk-based approach for ensuring microbiological safety. A risk-based approach allows consideration of the degree of exposure to assess unacceptable health risks. As there can be a number of advantages in using a risk-based approach to safety, this study explores the Codex Alimentarius (Codex) four-step Microbiological Risk Assessment (MRA) framework frequently used in the Food industry and examines how it can be applied to the safety assessment of personal care products. The hazard identification and hazard characterization steps (one and two) of the Codex MRA framework consider the main microorganisms of concern. These are addressed by reviewing the current industry guidelines for objectionable organisms and analysing reports of contaminated products notified by government agencies over a recent 5-year period, together with examples of reported outbreaks. Data related to estimation of exposure (step three) are discussed, and examples of possible calculations and references are included. The fourth step, performed by the risk assessor (risk characterization), is specific to each assessment and brings together the information from the first three steps to assess the risk. Although there are very few documented uses of the MRA approach for personal care products, this study illustrates that it is a practicable and sound approach for producing products that are safe by design. It can be helpful in the context of designing products and processes going to market and with setting of microbiological specifications. Additionally, it can be applied reactively to facilitate decision-making when contaminated products are released on to the marketplace. Currently, the knowledge available may only allow a qualitative or semi-quantitative rather than fully quantitative risk assessment, but an added benefit is that the disciplined structuring of available knowledge enables clear identification of gaps to target resources and if appropriate, instigate data generation.

Whole-genome association analysis of treatment response in obsessive-compulsive disorder

Up to 30% of patients with obsessive-compulsive disorder (OCD) exhibit an inadequate response to serotonin reuptake inhibitors (SRIs). To date, genetic predictors of OCD treatment response have not been systematically investigated using genome-wide association study (GWAS). To identify specific genetic variations potentially influencing SRI response, we conducted a GWAS study in 804 OCD patients with information on SRI response. SRI response was classified as 'response' (n=514) or 'non-response' (n=290), based on self-report. We used the more powerful Quasi-Likelihood Score Test (the MQLS test) to conduct a genome-wide association test correcting for relatedness, and then used an adjusted logistic model to evaluate the effect size of the variants in probands. The top single-nucleotide polymorphism (SNP) was rs17162912 (P=1.76 × 10(-8)), which is near the DISP1 gene on 1q41-q42, a microdeletion region implicated in neurological development. The other six SNPs showing suggestive evidence of association (P<10(-5)) were rs9303380, rs12437601, rs16988159, rs7676822, rs1911877 and rs723815. Among them, two SNPs in strong linkage disequilibrium, rs7676822 and rs1911877, located near the PCDH10 gene, gave P-values of 2.86 × 10(-6) and 8.41 × 10(-6), respectively. The other 35 variations with signals of potential significance (P<10(-4)) involve multiple genes expressed in the brain, including GRIN2B, PCDH10 and GPC6. Our enrichment analysis indicated suggestive roles of genes in the glutamatergic neurotransmission system (false discovery rate (FDR)=0.0097) and the serotonergic system (FDR=0.0213). Although the results presented may provide new insights into genetic mechanisms underlying treatment response in OCD, studies with larger sample sizes and detailed information on drug dosage and treatment duration are needed.

Mouse granzyme A induces a novel death with writhing morphology that is mechanistically distinct from granzyme B-induced apoptosis

Human and mouse granzyme (Gzm)B both induce target cell apoptosis in concert with pore-forming perforin (Pfp); however the mechanisms by which other Gzms induce non-apoptotic death remain controversial and poorly characterised. We used timelapse microscopy to document, quantitatively and in real time, the death of target cells exposed to primary natural killer (NK) cells from mice deficient in key Gzms. We found that in the vast majority of cases, NK cells from wild-type mice induced classic apoptosis. However, NK cells from syngeneic Gzm B-deficient mice induced a novel form of cell death characterised by slower kinetics and a pronounced, writhing, 'worm-like' morphology. Dying cells initially contracted but did not undergo membrane blebbing, and annexin-V staining was delayed until the onset of secondary necrosis. As it is different from any cell death process previously reported, we tentatively termed this cell death 'athetosis'. Two independent lines of evidence showed this alternate form of death was due to Gzm A: first, cell death was revealed in the absence of Gzm B, but was completely lost when the NK cells were deficient in both Gzm A and B; second, the athetotic morphology was precisely reproduced when recombinant mouse Gzm A was delivered by an otherwise innocuous dose of recombinant Pfp. Gzm A-mediated athetosis did not require caspase activation, early mitochondrial disruption or generation of reactive oxygen species, but did require an intact actin cytoskeleton and was abolished by latrunculin B and mycalolide B. This work defines an authentic role for mouse Gzm A in granule-induced cell death by cytotoxic lymphocytes.

Meta-analysis of association between obsessive-compulsive disorder and the 3' region of neuronal glutamate transporter gene SLC1A1

The neuronal glutamate transporter gene SLC1A1 is a candidate gene for obsessive-compulsive disorder (OCD) based on linkage studies and convergent evidence implicating glutamate in OCD etiology. The 3' end of SLC1A1 is the only genomic region with consistently demonstrated OCD association, especially when analyzing male-only probands. However, specific allele associations have not been consistently replicated, and recent OCD genome-wide association and meta-analysis studies have not incorporated all previously associated SLC1A1 SNPs. To clarify the nature of association between SLC1A1 and OCD, pooled analysis was performed on all available relevant raw study data, comprising a final sample of 815 trios, 306 cases and 634 controls. This revealed weak association between OCD and one of nine tested SLC1A1 polymorphisms (rs301443; uncorrected P = 0.046; non-significant corrected P). Secondary analyses of male-affecteds only (N = 358 trios and 133 cases) demonstrated modest association between OCD and a different SNP (rs12682807; uncorrected P = 0.012; non-significant corrected P). Findings of this meta-analysis are consistent with the trend of previous candidate gene studies in psychiatry and do not clarify the putative role of SLC1A1 in OCD pathophysiology. Nonetheless, it may be important to further examine the potential associations demonstrated in this amalgamated sample, especially since the SNPs with modest associations were not included in the more highly powered recent GWAS or in a past meta-analysis including five SLC1A1 polymorphisms. This study underscores the need for much larger sample sizes in future genetic association studies and suggests that next-generation sequencing may be beneficial in examining the potential role of rare variants in OCD.

TAC3/TACR3 mutations reveal preferential activation of gonadotropin-releasing hormone release by neurokinin B in neonatal life followed by reversal in adulthood

CONTEXT

Mutations in TAC3 and TACR3 (encoding neurokinin B and its receptor) have been identified in Turkish patients with idiopathic hypogonadotropic hypogonadism (IHH), but broader populations have not yet been tested and genotype-phenotype correlations have not been established.

OBJECTIVE

A broad cohort of normosmic IHH probands was screened for mutations in TAC3/TACR3 to evaluate the prevalence of such mutations and define the genotype/phenotype relationships.

DESIGN AND SETTING

The study consisted of sequencing of TAC3/TACR3, in vitro functional assays, and neuroendocrine phenotyping conducted in tertiary care centers worldwide.

PATIENTS OR OTHER PARTICIPANTS

345 probands, 18 family members, and 292 controls were studied.

INTERVENTION

Reproductive phenotypes throughout reproductive life and before and after therapy were examined.

MAIN OUTCOME MEASURE

Rare sequence variants in TAC3/TACR3 were detected.

RESULTS

In TACR3, 19 probands harbored 13 distinct coding sequence rare nucleotide variants [three nonsense mutations, six nonsynonymous, four synonymous (one predicted to affect splicing)]. In TAC3, one homozygous single base pair deletion was identified, resulting in complete loss of the neurokinin B decapeptide. Phenotypic information was available on 16 males and seven females with coding sequence variants in TACR3/TAC3. Of the 16 males, 15 had microphallus; none of the females had spontaneous thelarche. Seven of the 16 males and five of the seven females were assessed after discontinuation of therapy; six of the seven males and four of the five females demonstrated evidence for reversibility of their hypogonadotropism.

CONCLUSIONS

Mutations in the neurokinin B pathway are relatively common as causes of hypogonadism. Although the neurokinin B pathway appears essential during early sexual development, its importance in sustaining the integrity of the hypothalamic-pituitary-gonadal axis appears attenuated over time.

Epstein-Barr virus-encoded EBNA1 regulates cellular gene transcription and modulates the STAT1 and TGFbeta signaling pathways

The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all virus-associated tumors where it plays an essential role in the maintenance, replication and transcription of the EBV genome. Transcriptional profiling of EBNA1-expressing carcinoma cells demonstrated that EBNA1 also influences the expression of a range of cellular genes including those involved in translation, transcription and cell signaling. Of particular interest was the ability of EBNA1 to enhance expression of STAT1 and sensitize cells to interferon-induced STAT1 activation with resultant enhancement of major histocompatibility complex expression. A negative effect of EBNA1 on the expression of TGFbeta1-responsive betaig-h3 and PAI-1 genes was confirmed at the protein level in EBV-infected carcinoma cells. This effect resulted from the ability of EBNA1 to repress TGFbeta1-induced transcription via a reduction in the interaction of SMAD2 with SMAD4. More detailed analysis revealed that EBNA1 induces a lower steady-state level of SMAD2 protein as a consequence of increased protein turnover. These data show that EBNA1 can influence cellular gene transcription resulting in effects that may contribute to the development of EBV-associated tumors.

Practice MRI: reducing the need for sedation and general anaesthesia in children undergoing MRI

The aim of this study was to evaluate the effectiveness of a practice magnetic resonance unit, in preparing children to undergo magnetic resonance procedures without general anaesthesia (GA) or sedation. The records of children who attended the practice MRI between February 2002 and April 2004 were retrospectively reviewed. Each record was assessed as to whether the child had passed or failed the practice MRI intervention. Those children who were considered to have passed and were proceeded to a clinical non-GA MRI had the report of the clinical scan reviewed. If the scan had been reported as non-diagnostic because of movement artefact it was classified as a failed scan, otherwise it was considered a pass. One hundred and thirty-four children undertook a practice MRI (age range 4.1-16.1 years, median age 7.7 years, 47% boys) and 120/134 (90%) passed the practice session. In all, 117/120 (98%) subsequently had a clinical non-GA MRI and 110/117 (94%) passed (median age 7.8 years, 47% boys). Preparation is a safe and effective method to reduce the need for sedation and GA in children undergoing a clinical MRI scan. It provides a positive medical experience for children, parents and staff, and results in cost savings for the hospital.

Long-term outcome of pediatric obsessive-compulsive disorder: a meta-analysis and qualitative review of the literature

OBJECTIVE

To review the extant literature on the long-term outcome of child/adolescent-onset obsessive-compulsive disorder (OCD).

METHOD

Medline and Psychlit databases were systematically searched for articles regarding long-term outcomes of child/adolescent-onset OCD. Meta-analysis regression was applied to evaluate predictors and persistence of OCD.

RESULTS

Sixteen study samples (n = 6-132; total = 521 participants) in 22 studies had follow-up periods ranging between 1 and 15.6 years. Pooled mean persistence rates were 41% for full OCD and 60% for full or subthreshold OCD. Earlier age of OCD onset (z = -3.26, P = 0.001), increased OCD duration (z = 2.22, P = 0.027) and in-patient vs. out-patient status (z = 2.94, P = 0.003) predicted greater persistence. Comorbid psychiatric illness and poor initial treatment response were poor prognostic factors. Although psychosocial function was frequently compromised, most studies lacked comprehensive outcome measures.

CONCLUSION

Long-term persistence of pediatric OCD may be lower than believed. Future studies should include broader measures of outcome including symptomatic persistence and functional impairment in multiple domains.

Efficacy of Sandostatin LAR (long-acting somatostatin analogue) is similar in patients with untreated acromegaly and in those previously treated with surgery and/or radiotherapy

BACKGROUND AND OBJECTIVES

Somatostatin analogues have been used as an adjunct to surgery and radiotherapy in the treatment of acromegaly for over 15 years, but debate surrounds their use as primary therapy. Newman suggested that octreotide was equally effective as primary or adjuvant therapy, but the effects of previous surgery/radiotherapy may have led to a preselection bias. In an attempt to eliminate this bias, the efficacy of the depot somatostatin analogue Sandostatin LAR as primary and adjuvant therapy has been assessed using GH and IGF-I levels at diagnosis as baseline values.

DESIGN

We retrospectively analysed the GH and IGF-I data from a large multicentre study in which patients' biochemical response to treatment with the depot somatostatin analogue Sandostatin LAR as primary and adjuvant therapy was assessed. We used GH and IGF-I levels at diagnosis as baseline values to eliminate any preselection bias.

PATIENTS AND RESULTS

In 91 patients (42 male) studied, mean serum GH fell from 36.2 +/- 3.3 micro g/l (SEM) at diagnosis to 2.2 +/- 0.2 micro g/l after 48 weeks of treatment (P < 0.0001). In the primary (n = 34) and adjuvant (n = 57) therapy groups, mean GH fell from 30.7 +/- 5.7 to 2.6 +/- 0.4 micro g/l (P < 0.0001) and from 39.5 +/- 4.1 to 2.0 +/- 0.2 micro g/l (P < 0.0001), respectively. Sixty-two percent of patients in the primary therapy group and 70% in the adjuvant therapy group achieved GH < 2 micro g/l. Serum IGF-I levels were available in 67 patients (34 male). In the primary therapy group (n = 25) mean IGF-I fell from 764 +/- 68 to 414 +/- 31 micro g/l (P < 0.0001) at 48 weeks. In the adjuvant therapy group (n = 42) mean IGF-I was 666 +/- 50 micro g/l, falling to 384 +/- 30 micro g/l (P < 0.0001) at 48 weeks. 72% of patients achieved normal age-related IGF-I-values. There were no statistically significant differences in GH or IGF-I levels between the primary and adjuvant therapy groups at diagnosis, pre Sandostatin LAR or after 48 weeks of treatment.

CONCLUSION

This retrospective study demonstrates that in a group of patients with similar diagnostic GH and IGF-I levels, Sandostatin LAR was equally effective as primary therapy in acromegalic patients as in patients previously treated with surgery and/or radiotherapy.

Long-term safety and efficacy of depot long-acting somatostatin analogs for the treatment of acromegaly

Depot somatostatin analogs are now increasingly being prescribed as adjuvant and primary therapy for the treatment of acromegaly. Previous studies have shown them to be both effective and safe, suppressing GH levels to less than 2 micro g/liter in 50-65% of cases and normalizing serum IGF-I levels in 65%. However, published data on their long-term efficacy and safety is scanty. We analyzed data from 22 patients (16 female and 6 male) treated with Sandostatin LAR or Lanreotide for an average of 41 months (range 12-89). Three patients had previously been treated with surgery, two with radiotherapy, and seven with both. Ten patients had received primary medical therapy. Mean pretreatment GH levels were 13.1 +/- 3.4 micro g/liter, and IGF-I levels were 592.9 +/- 53.9 micro g/liter. Results after 12 months of therapy indicated reduction in GH (3.2 +/- 0.7 micro g/liter; P < 0.0001) and IGF-I (321.9 +/- 33.9 micro g/liter; P < 0.001) concentrations, and this was sustained at latest follow-up. Using GH criteria (serum GH < 2 micro g/liter), 46% of subjects achieved a cure at 12 months, and 36% achieved a cure long-term. Fifty-two percent achieved normal IGF-I values at 12 months, and 67% long-term. Mean fasting and 2-h plasma glucose concentrations were similar at latest follow-up and at 12 months to baseline values. Three patients developed impaired glucose tolerance within 12 months of treatment, one going on to develop frank diabetes mellitus. However, glucose tolerance improved in five patients. Five patients developed gallstones while on treatment. In summary, this study reports the long-term efficacy of the depot somatostatin analogs as either adjuvant or primary therapy. Although overall glucose tolerance did not change, the development of impaired glucose tolerance in three patients at a time when GH levels were not changing highlights the ongoing need to monitor the long-term safety of these preparations.

Timing and magnitude of frontal activity differentiates refixation and anti-saccade performance

EEG data were recorded while 10 subjects generated refixation saccades towards a visual target and antisaccades away from a visual cue. Theoretically, the same basic neural circuitry supports refixation and correct anti-saccade performances, with additional activity in primarily dorsolateral prefrontal cortex circuitry supporting antisaccade-associated inhibitory processes. Analyses demonstrated that sensory registration of visual stimuli is similar for refixation and anti-saccade conditions. Increased frontal brain activity at 5 and 15 Hz was observed preceding correct antisaccades when compared to refixation saccades. These analyses provide specific information suggesting that 160-60 ms before saccade generation is the critical period for response inhibition.

Suicidal children and adolescents with first emergency room presentations: predictors of six-month outcome

OBJECTIVE

To examine risk of future documented suicide attempts and emergency room (ER) returns among children and adolescents with first suicidal ER presentations.

METHOD

A total of 548 consecutive ER presentations of suicidal 5- to 19-year-olds to a Canadian center over a 1-year period (1997-1998) were reviewed. Relative risk analyses were performed on 224 first-time patients (mean age 14.6+/-2.1) to determine the strength of associations between predictors and outcomes (ER return and suicide attempts).

RESULTS

At 6-month follow-up, 32.6% (n = 73) had returned to the ER, 24.1% (n = 54) had a documented suicide attempt, and 14.3% (n = 32) required psychiatric hospitalization. Predictors for both ER return and future documented suicide attempts included 15- to 19-year age range, past foster/group home placement, past mental health care, a suicide plan, reported mood symptoms, sobriety at ER visit, and general substance use. Child welfare guardianship and abuse history were also predictors of ER returns.

CONCLUSIONS

Clinicians should be aware of these risk factors when assessing and managing suicidal youths with first ER presentations.

A convergent validity study of Cloninger's Temperament and Character Inventory with the Coolidge Axis II Inventory

This study examined the convergent validity of the Temperament and Character Inventory (TCI), a measure of four biosocial temperaments and three character dimensions with the Coolidge Axis II Inventory (CATI), a measure of 14 personality disorders. A nonclinical sample of 163 college students was given both measures, and the data were analyzed with bivariate and multivariate statistics. Hypotheses generated from the findings of Svrakic, Whitehead, Przybeck, and Cloninger (1993, Archives of General Psychiatry, 50, 991-999) were confirmed for a majority of the relationships between the two measures. The preliminary results provide qualified support for the TCI and Cloninger's biosocial theory in the assessment of personality disorders.

Clinical and biochemical response following withdrawal of a long-acting, depot injection form of octreotide (Sandostatin-LAR)

OBJECTIVE

Monthly injections of Sandostatin-LAR have been shown to be an effective therapy for patients with acromegaly. Because of an ongoing need to assess a patients response to definitive therapy such as surgery and/or radiotherapy, we aimed to evaluate GH levels and acromegaly symptom scores in patients withdrawing from Sandostatin-LAR.

DESIGN AND PATIENTS

12 patients with acromegaly previously treated with Sandostatin-LAR, 20-40 mg intramuscularly every 28 (n = 9) or 42 (n = 3) days for 12-36 months were studied at monthly intervals for 4 months following the withdrawal of the drug.

MEASUREMENTS

Hourly fasting serum GH measurements between 0800 h and 1200 h, serum IGF-1 and symptom scores were undertaken at 4, 8, 12 and 16 weeks following the last injection of Sandostatin-LAR. MRI/CT scans of the pituitary were undertaken at 16 weeks and compared to scans taken on Sandostatin-LAR within the previous 10 months.

RESULTS

Serum GH rose progressively from 7.7 (1.5 to 14.6) (median (range)) mIU/l at 4 weeks to 9.9 (1.5-21.8), to 12.6 (4.9-31.9) (P < 0.05 vs 4 weeks) and to 13.1 (6.0-39.1) mIU/l (P < 0.002) at 8, 12 and 16 weeks, respectively, following cessation of Sandostatin-LAR. IGF-1 rose from 38.5 (12.6-73.8) nmol/l at 4 weeks to 62.4 (37.4-159) at 16 weeks (P < 0.002) and mean symptom score (comprising headache, sweating, arthralgia, paraesthesiae, tiredness) from 4.0 (0 to 10) (4 weeks) to 4.5 (0-9) (8 weeks) to 6.0 (2-10) (12 weeks) to 6.5 (4-12) (16 weeks, P < 0.05). Individual GH profiles indicated a rise in GH in 5/12 patients between weeks 4-8 and between weeks 8-12 in a further 5/12 patients. There were no changes in pituitary tumour size following discontinuation of Sandostatin-LAR.

CONCLUSIONS

GH and symptom scores rise progressively following discontinuation of Sandostatin-LAR in acromegalic patients. However, GH and symptom scores remain suppressed in some patients for at least 8 weeks following cessation of Sandostatin-LAR. We suggest that a withdrawal period of 3 months from Sandostatin-LAR is required in order to perform a meaningful re-assessment of GH and clinical status.

Long-term therapy with long-acting octreotide (Sandostatin-LAR) for the management of acromegaly

OBJECTIVES

To evaluate the efficacy and safety of a long-acting preparation of the somatostatin analogue octreotide, Sandostatin-LAR (SMS-LAR) for the treatment of acromegaly.

DESIGN AND PATIENTS

Thirteen patients with acromegaly received intramuscular injections of SMS-LAR 20-40 mg at 4-6 week intervals for a period of up to 3 years.

MEASUREMENTS

Serial measurement of serum GH and IGF concentrations were obtained. Symptoms related to acromegaly were scored by patients at baseline and following each injection. Serial gallbladder ultrasound and pituitary imaging was performed throughout the study.

RESULTS

One patient was withdrawn from the study after 6 months because of continued gastrointestinal side effects; 4 patients were treated with monthly injections for 12 months and 8 patients with injections at either 1 month or 6-week intervals for 36 months; hence data is presented for n = 12 for up to 12 months; and thereafter n = 8. SMS-LAR significantly reduced serum GH and IGF-1 values: for the whole group GH concentrations fell from 24.8 +/- 4.2 mU/l (mean +/- SE) at baseline to 5.2 +/- 0.8 mU/l at 12 months (P < 0.01, n = 12). In the 8 patients treated for 3 years GH fell from 27.8 +/- 6.1 mU/l at baseline to 4.2 +/- 0.8 mU/l at the end of 3 years (P < 0.01, n = 8). GH fell to < 10 mU/l in all subjects and was < 5 mU/l in 50% after both 1 and 3 years. IGF-1 concentrations fell from 95 +/- 13 nmol/l at baseline to 63 +/- 13 nmol/l after 1 year (P < 0.01, n = 12; reference range < 65 nmol/l). In the 8 patients treated for 3 years IGF-1 concentrations fell from 119 +/- 14 nmol/l at baseline to 60 +/- 13 nmol/l after 3 years (P < 0.001, n = 8). IGF-1 was < 65 nmol/l in 60% of patients after 1 year and 75% after 3 years. Treatment resulted in trends towards improvement in symptoms of acromegaly and statistically significant improvement in sweating. There was no evidence of tachyphylaxis or evidence to suggest development of glucose intolerance. Only 2 patients (15%) developed gallbladder sludge which was asymptomatic; no patient developed gallstones.

CONCLUSIONS

We conclude that SMS-LAR is a safe, effective and well tolerated treatment, making it an important therapeutic option in the management of acromegaly.

Sequence and expression pattern of J chain in the amphibian, Xenopus laevis

We have determined the cDNA sequence encoding J chain, a polypeptide accessory molecule associated with polymeric Ig, from the anuran amphibian, Xenopus laevis (South African clawed frog). The translated polypeptide consists of 164 amino acid residues, including the signal sequence, and is somewhat longer than the corresponding sequence in mouse and cow, the two mammalian species in which the signal sequence of J chain has been determined. J chain in several mammalian species (human, mouse, cow and rabbit) has eight Cys residues. In the human chain, two of these Cys residues, the second and third in the sequence, have been shown to form disulfide bridges to heavy chains in IgM or IgA; the remaining Cys residues form intrachain disulfide bonds. The Xenopus J chain contains only seven of these Cys residues. Ser is found at the position corresponding to the third Cys in mammalian J chains. Northern blot analysis, performed on RNA isolated from various organs of 3-month old frogs, indicated that the highest level of expression was in the intestine. Transcripts corresponding to J chain were also detected in the spleen and at very low levels in the thymus.

Depot long-acting somatostatin analog (Sandostatin-LAR) is an effective treatment for acromegaly

Octreotide (Sandostatin) is a synthetic analog of somatostatin, an endogenous GH inhibitory peptide that has been used as an adjunct to surgery and radiotherapy in the treatment of acromegaly. When given sc in divided daily doses, it lowers serum GH to less than 5 micrograms/L in approximately 50% of cases. Data suggest that continuous infusions of somatostatin analogs may be more effective in lowering GH. We have evaluated Sandostatin-LAR, a new long-acting preparation of Sandostatin, in eight patients with acromegaly. After an initial pharmacokinetic study, patients received a minimum of 10 im injections of Sandostatin-LAR (20, 30, or 40 mg) at 28- or 42-day intervals. Serum GH levels decreased from 10.7 +/- 2.8 micrograms/L (mean +/- SE) at baseline to a nadir of 2.6 +/- 0.4 micrograms/L after the tenth injection, and to less than 5 micrograms/L in every patient. Serum insulin-like growth factor-I decreased from 927 +/- 108 ng/mL at baseline to 472 +/- 59 ng/mL at the end of the sixth injection and returned to normal (< 500 ng/mL) in seven of the eight patients. This was associated with significant improvements in headache, arthralgia, and sweating. There was no evidence of octreotide accumulation, and the drug was well tolerated. To date, no gallstones have occurred, and serial pituitary imaging has revealed no increase in the size of the initial pituitary tumor. In particular, two previously untreated patients have shown complete regression of the initial microadenoma and have serum GH values of less than 2.5 micrograms/L. Sandostatin-LAR is an effective and well-tolerated treatment for patients with acromegaly. Undoubtedly the initial indication for Sandostatin-LAR will be in the patient who is not cured after surgery and radiotherapy, but our experience suggests that it may be used as a primary treatment in some acromegalics.

Diversity of expressed V and J regions of immunoglobulin light chains in Xenopus laevis

In Xenopus laevis, two immunoglobulin light chain isotypes, designated L1 or rho and L2 or sigma, have been identified. The genomic organization of the L1 locus has been described previously: a constant (C) gene segment is preceded by a joining (J) gene segment; in addition, there are many cross-hybridizing variable (V) gene segments. To evaluate the extent of sequence diversity of L1 V regions, we screened three cDNA libraries, constructed from mitogen-stimulated Xenopus splenocytes, with probes for the C or the J gene segment. Eighteen cDNA clones that contain complete or truncated V regions were chosen for sequence analysis. The C regions of all clones are identical or nearly identical to the genomic C gene segment; the V regions are greater than 80% identical in nucleotide sequence and are presumably derived from a single family of V gene segments. Although framework regions are nearly identical, complementarity-determining regions are quite diverse. The expressed J segments fall into distinct groups, suggesting the presence of more than one germ-line J segment. Therefore, a genomic library was screened with a J region probe. A clone overlapping with the previously identified J-C clone, and containing four additional J gene segments, was isolated. All five J gene segments are very similar and three are identical in nucleotide sequence. Each of the three distinct germ-line J sequences is represented in the set of cDNA clones, suggesting that combinatorial diversification occurs; imprecision of V-J joining also appears to contribute to variability. Overall, these results suggest that the immunoglobulin repertoire in this species is not significantly restricted by a limitation in the diversity of light chain V regions.

Genes encoding Xenopus laevis Ig L chains. Implications for the evolution of kappa and lambda chains

Xenopus laevis Ig contain two distinct types of L chains, designated rho or L1 and sigma or L2. We have analyzed Xenopus genomic DNA by Southern blotting with cDNA probes specific for L1 V and C regions. Many fragments hybridized to the V probe, but only one or two fragments hybridized to the C probe. Corresponding C, J, and V gene segments were identified on clones isolated from a genomic library prepared from the same DNA. One clone contains a C gene segment separated from a J gene segment by an intron of 3.4 kb. The J and C gene segments are nearly identical in sequence to cDNA clones analyzed previously. The C segment is somewhat more similar and the J segment considerably more similar in sequence to the corresponding segments of mammalian kappa chains than to those of mammalian lambda chains. Upstream of the J segment is a typical recombination signal sequence with a spacer of 23 bp, as in J kappa. A second clone from the library contains four V gene segments, separated by 2.1 to 3.6 kb. Two of these, V1 and V3, have the expected structural and regulatory features of V genes, and are very similar in sequence to each other and to mammalian V kappa. A third gene segment, V2, resembles V1 and V3 in its coding region and nearby 5'-flanking region, but diverges in sequence 5' to position -95 with loss of the octamer promoter element. The fourth V-like segment is similar to the others at the 3'-end, but upstream of codon 64 bears no resemblance in sequence to any Ig V region. All four V segments have typical recombination signal sequences with 12-bp spacers at their 3'-ends, as in V kappa. Taken together, the data suggest that Xenopus L1 L chain genes are members of the kappa gene family.

Genes encoding Xenopus laevis Ig L chains. Implications for the evolution of kappa and lambda chains

Xenopus laevis Ig contain two distinct types of L chains, designated rho or L1 and sigma or L2. We have analyzed Xenopus genomic DNA by Southern blotting with cDNA probes specific for L1 V and C regions. Many fragments hybridized to the V probe, but only one or two fragments hybridized to the C probe. Corresponding C, J, and V gene segments were identified on clones isolated from a genomic library prepared from the same DNA. One clone contains a C gene segment separated from a J gene segment by an intron of 3.4 kb. The J and C gene segments are nearly identical in sequence to cDNA clones analyzed previously. The C segment is somewhat more similar and the J segment considerably more similar in sequence to the corresponding segments of mammalian kappa chains than to those of mammalian lambda chains. Upstream of the J segment is a typical recombination signal sequence with a spacer of 23 bp, as in J kappa. A second clone from the library contains four V gene segments, separated by 2.1 to 3.6 kb. Two of these, V1 and V3, have the expected structural and regulatory features of V genes, and are very similar in sequence to each other and to mammalian V kappa. A third gene segment, V2, resembles V1 and V3 in its coding region and nearby 5'-flanking region, but diverges in sequence 5' to position -95 with loss of the octamer promoter element. The fourth V-like segment is similar to the others at the 3'-end, but upstream of codon 64 bears no resemblance in sequence to any Ig V region. All four V segments have typical recombination signal sequences with 12-bp spacers at their 3'-ends, as in V kappa. Taken together, the data suggest that Xenopus L1 L chain genes are members of the kappa gene family.

Transcription by RNA polymerase I stimulates mitotic recombination in Saccharomyces cerevisiae

The recombination-stimulating sequence HOT1 is derived from the ribosomal DNA array of Saccharomyces cerevisiae and corresponds to sequences that promote transcription by RNA polymerase I. When inserted at a chromosomal location outside the ribosomal DNA array, HOT1 stimulates mitotic recombination in the adjacent sequences. To investigate the relationship between transcription and recombination, transcription promoted by HOT1 was directly examined. These studies demonstrated that transcription starts at the RNA polymerase I initiation site in HOT1 and proceeds through the chromosomal sequences in which recombination is enhanced. Linker insertion mutations in HOT1 were generated and assayed for recombination stimulation and for promoter function; this analysis demonstrated that the same sequences are required for both activities. These results indicate that the ability of HOT1 to enhance recombination is related to, and most likely dependent on, its ability to promote transcription.

Lithium carbonate--a competitive aldosterone antagonist?

Plasma renin activity (PRA), aldosterone (aldo) levels, electrolyte levels, and blood pressures were measured in 16 patients with affective disorders taking lithium prophylactically, and in 16 age and sex-matched control subjects. PRA and aldo levels were significantly elevated in the lithium-treated group. There was no difference between the groups in plasma electrolytes or erect and supine blood pressures, arguing against secondary aldosteronism. In the lithium-treated group, there was a significant positive correlation between both PRA and plasma aldo vs serum lithium. We postulate that lithium inhibits the action of aldosterone on the distal tubule in the kidney. Activation of the renin angiotensin system maintains normal blood pressure and plasma electrolytes.

High sodium intake increases platelet aggregation in normal females

Platelet activation and aggregation appear to play an important part in the development of vascular disease. We studied the effect of varying sodium intake on total plasma serotonin and in vitro aggregation of blood platelets. A total of 12 normal female volunteers were studied after 5 days on a 10 or 200 mmol/day sodium diet. Aggregation studies were performed by incubating stirred platelet-rich plasma (PRP) with adenosine diphosphate (ADP) at final concentrations of 1 and 4 mumol/l; we also studied the effect of pre-incubating PRP with ketanserin or saralasin (1 mumol/l and 1 nmol/l final concentration, respectively). Salt-loading produced a significant increase in platelet aggregation induced by both 1 and 4 mumol/l ADP, and also a significant fall in PRP in serotonin concentration; since there was also a significant drop in the yield of platelets in PRP during salt-loading, the difference in serotonin concentration was not significant when expressed as pmol serotonin/10(8) platelets. There was a significant negative correlation between log serotonin levels (nmol/l) and % aggregation induced by 4 mumol/l ADP. Ketanserin decreased aggregation (induced by 4 mumol/l ADP) in PRP obtained during high salt intake; saralasin had no effect on aggregation, but did cause a decrease in light transmission. These results indicate that in normal females: (1) in vitro platelet aggregation is increased with high sodium intake, and this effect was reduced by addition of ketanserin; (2) PRP platelet count and total plasma serotonin levels are both significantly altered by changes in sodium status; (3) aggregation (%) is inversely proportional to log serotonin concentration (nmol/l).

Cold-sensitive cell-division-cycle mutants of yeast: isolation, properties, and pseudoreversion studies

We isolated 18 independent recessive cold-sensitive cell-division-cycle (cdc) mutants of Saccharomyces cerevisiae, in nine complementation groups. Terminal phenotypes exhibited include medial nuclear division, cytokinesis, and a previously undescribed terminal phenotype consisting of cells with a single small bud and an undivided nucleus. Four of the cold-sensitive mutants proved to be alleles of CDC11, while the remaining mutants defined at least six new cell-division-cycle genes: CDC44, CDC45, CDC48, CDC49, CDC50 and CDC51.--Spontaneous revertants from cold-sensitivity of four of the medial nuclear division cs cdc mutants were screened for simultaneous acquisition of a temperature-sensitive phenotype. The temperature-sensitive revertants of four different cs cdc mutants carried single new mutations, called Sup/Ts to denote their dual phenotype: suppression of the cold-sensitivity and concomitant conditional lethality at 37 degrees. Many of the Sup/Ts mutations exhibited a cell-division-cycle terminal phenotype at the high temperature, and they defined two new cdc genes (CDC46 and CDC47). Two cold-sensitive medial nuclear division cdc mutants representing two different cdc genes were suppressed by different Sup/Ts alleles of another gene which also bears a medial nuclear division function (CDC46). In addition, the cold-sensitive medial nuclear division cdc mutant csH80 was suppressed by a Sup/Ts mutation yielding an unbudded terminal phenotype with an undivided nucleus at the high temperature. This mutation was an allele of CDC32. These results suggest a pattern of interaction among cdc gene products and indicate that cdc gene proteins might act in the cell cycle as complex specific functional assemblies.

Biologic interaction of gamma radiation with phenylbutazone, phenytoin, or hydralazine

Combination of repeated administration of phenylbutazone (7 mg/kg for two weeks) or phenytoin (20 mg/kg for four weeks) and acute exposure to gamma radiation (696 REM) induced increased lethality in mice much greater than that observed fro use of either drug or radiation alone. Lethality in chronic hydralazine (10 mg/kg for four weeks) treated mice subjected also to gamma radiation was not different than that observed after either drug or radiation alone. Decrease in liver glutathione was observed in mice receiving combined drug-radiation treatment as also were leucocyte counts, but neither of these parameters supported as assumption of site of common lethal mechanism.

Sterile host yeasts (SHY): a eukaryotic system of biological containment for recombinant DNA experiments

A system of biological containment for recombinant DNA experiments in Saccharomyces cerevisiae (Brewer's/Baker's yeast) is described. The principle of containment is sterility: the haploid host strains all contain a mating-type-non-specific sterile mutation. The hosts also contain four auxotrophic mutations suitable for selection for the various kinds of vectors used. All vectors are derivatives of pBR322 which can be selected and maintained in both yeast and Escherichia coli. The system has recently been certified at the HV2 level by the National Institutes of Health.

Studies on the intracisternal A-type particles in mouse plasma cell tumors: induction of maturation of the particles

Maturation of the intracisternal A-type particle found in two mouse plasma cell tumors was induced by treating the cells in culture with IDU-DMSO or with DMSO only. Morphologically, the mature particles with electron-dense nucleoids closely resembled the mature particles described in human tumor cell lines treated in a like manner. They also closely resembled the virus that has been described in guinea pig leukemias. It was not possible to demonstrate infectivity of the mature particle, as latent intracisternal A-type particles induced by IDU were found in the mouse cells presumed to be free of virus. The biochemical studies did not show distinct new peaks of virus-specific particles in sucrose density gradients when the particles in the treated cells were compared with the particles of the untreated cells. There was a difference in the density of the particles observed in the induced cells (1.2) and those of the control cells (1.185). This may reflect the difficulty of separating mature and immature particles. Analysis of the RNA present in the particles showed that the ratio of heavy-molecular-weight RNA in activated cells to the predominant species (21S) is much greater than that in control cells. Detectable levels of enzyme activity were not found in the induced particles. This could be due to too low a concentration of particles in the preparations.

Activation of viruses in human tumors by 5-iododeoxyuridine and dimethyl sulfoxide

Dimethyl sulfoxide added to cultures first treated with 5-iododeoxyuridine increased C-type virus production approximately tenfold in a human rhabdomyosarcoma cell line. 5-Iododeoxyuridine followed by dimethyl sulfoxide also activated a similar C-type virus in a metastatic tumor from a bronchial node taken from a 52-year-old male.