c-Kit Mutation and Localization Status as Response Predictors in Mast Cell Tumors in Dogs Treated with Prednisone and Toceranib or Vinblastine

Background

KIT inhibitors, such as toceranib (TOC), and vinblastine (VBL) have not been prospectively compared in the treatment of macroscopic mast cell tumors (MCTs). Also, it is unknown whether VBL or TOC is superior for treating MCT without c‐kit mutations.

Hypothesis/Objectives

To determine the value of KIT genotyping and localization in treatment decisions for dogs with macroscopic MCT. We hypothesized that c‐kit mutated MCT would have a better response to TOC than VBL.

Animals

Eighty‐eight client‐owned dogs with macroscopic MCT.

Methods

Prospective, randomized trial. Dogs were randomized to TOC (2.75 mg/kg EOD) or VBL (2.5 mg/m² weekly × 4 then EOW) by KIT localization and c‐kit mutation status using an adaptive randomization scheme.

Results

Sixty dogs were allocated to TOC and 28 to VBL. Of the dogs receiving TOC, 20% had c‐kit mutations, compared to 30% receiving VBL (P = 0.74). Overall response rates were 46% (TOC) and 30% (VBL) (odds ratio = 1.56 [0.62–3.92]; P = 0.28). Median progression‐free survival (PFS) for dogs receiving VBL was 78 days (7–1,521) and for TOC 95.5 (14–990); hazard ratio (HR) = 1.34 [0.72–2.50]; P = 0.36. Median overall survival (OS) was 241.5 days (10–1,521) for the VBL group and 159 (20–990) for the TOC group; HR = 0.80 ([0.45–1.41]; P = 0.44).

Conclusions and Clinical Importance

Neither PFS nor OS was significantly different between treatment groups. As the proportion of dogs with c‐kit mutations was not different between treatment groups in this population of dogs, c‐kit mutation status did not predict treatment response.

Assessment of Cyclooxygenase-2 Expression in Canine Hemangiosarcoma, Histiocytic Sarcoma, and Mast Cell Tumor

To determine whether cyclooxygenase-2 (COX-2) is expressed in canine hemangiosarcoma (HsA), histiocytic sarcoma (Hs), and grade-II mast cell tumor (MCT), we performed immunohistochemistry using COX-2 antibodies in the aforementioned tumors. Twenty cases of each tumor type were selected initially from the Laboratory of Pathology archives of cases submitted through the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania. Immunohistochemistry was performed, using a polyclonal antiprostaglandin endoperoxide synthase immunoglobulin G COX-2 antibody. Sections from the kidneys of young dogs, in which the macula densa stains positive for COX-2, served as positive controls. Slides were reviewed by a single pathologist (M. H. Goldschmidt) and graded for COX-2 expression according to previously established scales.18 Descriptive data is given for each tumor type. COX-2 expression was identified in 0 of 19 HSA, 1 of 20 HS, and 1 of 17 grade-II MCT. Although COX-2 has been shown to be overexpressed in selected human sarcomas and hematopoeitic tumors, these results indicate that canine HSA, HS, and MCT do not express COX-2 in any appreciable fashion.

Cyclooxygenase-2 Expression is Associated with Histologic Tumor Type in Canine Mammary Carcinoma

Cyclooxygenase-2 (COX-2) is an inducible member of the family of cyclooxygenase enzymes that has been implicated in the genesis of numerous cancers. The role of COX-2 in canine mammary neoplasia remains to be more clearly elucidated. The goal of the study reported here was to determine whether a direct association between levels of COX-2 expression and tumor histologic subtype exists in canine mammary carcinoma. Immunohistochemical analysis was performed using a polyclonal antiprostaglandin G/H synthase 2 IgG COX-2 antibody. Sections from the kidneys of young dogs, which stain positive for COX-2 in the macula densa, served as positive controls. Slides were reviewed by a single pathologist, and were evaluated for COX-2 expression according to previously established scales. Positive-staining tumors were given a COX-2 staining distribution (on the basis of the percentage of positive staining cells in five 400x fields) and intensity score according to previously established scales. The product of the COX-2 staining distribution and intensity scores was calculated to create a COX-2 staining index. COX-2 expression was detected in 28 of 50 (56%) samples evaluated. Anaplastic carcinomas had a significantly higher COX-2 staining distribution, intensity, and index, compared with those for adenocarcinomas ( P < 0.0001). The overall percentage of positive tumors (56%) was consistent with that of prior studies. To the authors' knowledge, these results indicate, for the first time, a direct association between COX-2 expression and tumor histologic subtype in canine mammary carcinomas. Future research directed at measuring tumor response in canine mammary carcinoma patients treated with a selective COX-2 inhibitor is indicated.

Extravasation reactions associated with the administration of pamidronate: 11 cases (2008-2013)

Pamidronate is a bisphosphonate drug widely utilized in veterinary oncologic practice for the palliation of malignant osteolysis. Pamidronate has not been previously reported to cause tissue injury upon extravasation in dogs. The medical records of 11 client-owned dogs undergoing palliative treatment for primary bone tumors with known or suspected pamidronate extravasation reactions were reviewed. The majority of adverse events were low grade in nature, however in some cases, the reactions were severe and led to euthanasia in one instance. Time to complete resolution of lesions ranged from within several days to greater than one and a half months. Aside from the dog that was euthanized, no long-term sequelae of extravasation were identified. Treatments employed to address the reactions varied widely. Pamidronate extravasation reaction appears to be an uncommon, but potentially serious complication of intravenous administration.

Pulse-Administered Toceranib Phosphate Plus Lomustine for Treatment of Unresectable Mast Cell Tumors in Dogs

BACKGROUND

Nonresectable mast cell tumors (MCT) in dogs remain a therapeutic challenge, and investigation of novel combination therapies is warranted. Intermittent administration of tyrosine kinase inhibitors (TKI) combined with cytotoxic chemotherapy may effectively chemosensitize canine MCT while decreasing cost and adverse effects associated with either agent administered as monotherapy.

HYPOTHESIS/OBJECTIVES

The primary study objectives were to (1) identify the maximally tolerated dose (MTD), (2) determine the objective response rate (ORR) and (3) describe the adverse event profile of pulse-administered toceranib phosphate (TOC) combined with lomustine.

ANIMALS

Forty-seven client-owned dogs with measurable MCT.

METHODS

Toceranib phosphate was given PO on days 1, 3 and 5 of a 21-day cycle at a target dosage of 2.75 mg/kg. Lomustine was given PO on day 3 of each cycle at a starting dosage of 50 mg/m(2) . All dogs were concurrently treated with diphenhydramine, omeprazole, and prednisone.

RESULTS

The MTD of lomustine was established at 50 mg/m(2) when combined with pulse-administered TOC; the dose-limiting toxicity was neutropenia. Forty-one dogs treated at the MTD were evaluable for outcome assessment. The ORR was 46% (4 complete response, 15 partial response) and the overall median progression-free survival (PFS) was 53 days (1 to >752 days). On multivariate analysis, variables significantly associated with improved PFS included response to treatment, absence of metastasis, and no previous chemotherapy.

CONCLUSIONS AND CLINICAL IMPORTANCE

Combined treatment with pulse-administered TOC and lomustine generally is well tolerated and may be a reasonable treatment option for dogs with unresectable or metastatic MCT.

Early tumor response to intraarterial or intravenous administration of carboplatin to treat naturally occurring lower urinary tract carcinoma in dogs

Background

Survival times and tumor responses associated with malignant neoplasia of the lower urinary tract are poor despite the vast array of current treatments. Therefore, the evaluation of alternative treatments, such as intraarterial administration of chemotherapy (IAC) should be considered.

Objective

To describe a technique for superselective catheterization for IAC and to evaluate initial tumor response by ultrasonography after both IAC and intravenous administration of chemotherapy (IVC).

Animals

Client‐owned dogs with lower urinary tract neoplasia treated with either IVC (n = 15) or IAC (n = 11).

Methods

Retrospective study. An arterial approach via the carotid or femoral artery was utilized to obtain superselective access and administer chemotherapy in the IAC cases. Medical record review was performed, data were recorded, and recorded variables were evaluated statistically.

Results

Intraarterial chemotherapy was successfully administered in all cases. There was a significantly greater decrease in longest unidimensional measurement in the IAC group as compared to the IVC group (P = .013). The IAC group was also significantly more likely to have a tumor response as assessed by modified RECIST guidelines (P = .049). Dogs in the IAC group were significantly less likely to develop anemia (P = .001), lethargy (P = .010) and anorexia (P = .024).

Conclusion and Clinical Importance

This study demonstrated the feasibility and efficacy of performing IAC for lower urinary tract neoplasia. Further investigation is necessary as the follow‐up time was short and the impact on long‐term outcome and survival was not determined.

Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs†

Sixty-four dogs were treated with single-agent doxorubicin (DOX) for presumptive cardiac hemangiosarcoma (cHSA). The objective response rate (CR + PR) was 41%, and the biologic response rate (CR + PR + SD), or clinical benefit, was 68%. The median progression-free survival (PFS) for treated dogs was 66 days. The median survival time (MST) for this group was 116 days and was significantly improved compared to a MST of 12 days for untreated control dogs (P = 0.0001). Biologic response was significantly associated with improved PFS (P < 0.0001) and OS (P < 0.0001). Univariate analysis identified larger tumour size as a variable negatively associated with PFS. The high rate of clinical benefit and improved MST suggest that DOX has activity in canine cHSA.

Characterization of the biological behaviour of appendicular osteosarcoma in Rottweilers and a comparison with other breeds: a review of 258 dogs

The purpose of this retrospective study was to compare Rottweilers diagnosed with osteosarcoma (OSA) with other breeds to determine whether Rottweilers experienced a more aggressive form of the disease. Two hundred and fifty-eight dogs were evaluated (102 clinical and 156 necropsy cases). In the necropsy population, Rottweilers had a younger mean age at death (7.3 versus 9 years, P = 0.006). There were no significant differences between Rottweilers and other breeds in age at diagnosis, median disease-free interval or survival time. However, Rottweilers were more likely to have metastasis to the brain (7 versus 0%, P = 0.03). These results suggest that OSA in Rottweilers may have a different biological behaviour, but this study did not confirm that these differences were associated with a worse outcome.

Efficacy of doxorubicin-based chemotherapy for non-resectable canine subcutaneous haemangiosarcoma

Eighteen dogs with measurable subcutaneous haemangiosarcoma (SQHSA) were treated with doxorubicin-based chemotherapy. Response assessment was evaluated and compared using World Health Organization (WHO), Response Evaluation Criteria in Solid Tumours (RECIST) and tumour volume criteria. The overall response rate for all dogs was 38.8% using WHO criteria, 38.8% using RECIST criteria and 44% using tumour volume criteria. One dog had a complete response. The median response duration for all dogs was 53 days (range 13-190 days). Four dogs had complete surgical excision after neoadjuvant chemotherapy. The median progression-free interval for dogs with complete surgical excision after neoadjuvant chemotherapy was significantly longer than those not having surgical excision (207 days versus 83 days, respectively) (P = 0.003). No significant difference in metastasis-free interval or survival time was found between the groups. Doxorubicin-based chemotherapy appears to be effective for non-resectable canine SQHSA, although the response duration is relatively short.

Progression of a solitary, malignant cutaneous plasma-cell tumour to multiple myeloma in a cat

An 11-year-old male domestic shorthair cat was examined because of a soft-tissue mass on the left tarsus previously diagnosed as a malignant extramedullary plasmacytoma. Findings of further diagnostic tests carried out to evaluate the patient for multiple myeloma were negative. Five months later, the cat developed clinical evidence of multiple myeloma based on positive Bence Jones proteinuria, monoclonal gammopathy and circulating atypical plasma cells. This case represents an unusual presentation for this disease and documents progression of an extramedullary plasmacytoma to multiple myeloma in the cat.

Long-term survival in dogs with localized histiocytic sarcoma treated with CCNU as an adjuvant to local therapy

Histiocytic sarcoma (HS) is associated with a poor prognosis owing to the presence of metastasis at the time of diagnosis in most dogs. Improved outcome has been reported in several dogs with localized HS following local therapy, however, distant metastasis occurs in 70-91% of dogs suggesting that adjuvant systemic therapy is necessary. The purpose of this retrospective study was to describe clinical characteristics and outcome in dogs with localized HS treated with aggressive local therapy plus adjuvant CCNU chemotherapy. Data from 16 dogs were evaluated. The median disease-free interval was 243 days. Two dogs had local recurrence and eight dogs developed metastatic disease with a median time to relapse of 201 days in these 10 dogs. The median survival time for all 16 dogs was 568 days. These results support the recommendation for aggressive local therapy combined with adjuvant CCNU chemotherapy in dogs with localized HS.

Description of clinical and pathological findings, treatment and outcome of feline large granular lymphocyte lymphoma (1996-2004)

Feline large granular lymphocyte (LGL) lymphoma is an uncommon, morphologically distinct variant of feline lymphoma. Limited information exists in the literature regarding pathological and immunohistochemical descriptions, clinical findings, treatment and survival times. The purpose of this study was to describe clinical features, treatment and outcome in feline LGL lymphoma. Medical records of 45 cats with LGL lymphoma were retrospectively evaluated. Decreased appetite/anorexia, weight loss, lethargy and vomiting were the most commonly reported clinical signs. All cats tested for feline leukaemia virus and feline immunodeficiency virus infection were negative. The mesenteric lymph nodes and small intestine were the most commonly affected organs. One complete response and six partial responses were noted in the 23 cats that received chemotherapy as their initial treatment. Median survival time for cats that were treated was 57 days. Based on these results, feline LGL lymphoma appears to be minimally responsive to chemotherapy and is associated with a grave prognosis.

Survival analysis of 97 cats with nasal lymphoma: a multi-institutional retrospective study (1986-2006)

BACKGROUND

Feline nasal lymphoma (NLSA) is a condition for which no standard of care exists.

HYPOTHESIS

There is no difference in survival times of cats with NLSA treated with single or multimodality therapy.

ANIMALS

Records from 97 cats diagnosed with NLSA were examined.

METHODS

The purpose of this retrospective study was to compare the survival times of cats with NLSA treated with radiation therapy (RT) alone, chemotherapy alone, or RT + chemotherapy and identify potential prognostic variables that affected survival. Cats were grouped according to therapy: RT + chemotherapy (n = 60), RT alone (n = 19), or chemotherapy alone (n = 18).

RESULTS

Survival was calculated with 2 methods. The 1st survival analysis (method A) included all cats, but counted only deaths caused by progressive NLSA. The median survival time (MST), regardless of therapy modality, was 536 days. The 2nd survival analysis (method B) also included all cats and counted all deaths, regardless of cause, as events. The overall MST calculated for all deaths was 172 days. A negative independent prognostic variable identified was anemia (P < .001), and positive independent prognostic variables were a complete response to therapy (P < .001) and total radiation dose >32 Gy (P= .03).

CONCLUSIONS AND CLINICAL IMPORTANCE

There were no significant differences in survival times among the 3 treatment groups but these results suggest that the addition of higher doses of RT to a cat's treatment protocol may control local disease and therefore influence survival.

Response of canine cutaneous epitheliotropic lymphoma to lomustine (CCNU): a retrospective study of 46 cases (1999-2004)

BACKGROUND

Epitheliotropic lymphoma (ELSA) is an uncommon cutaneous canine malignancy of T lymphocytes. A consensus regarding the therapeutic standard of care is lacking, warranting evaluation of chemotherapeutic agents traditionally employed against canine nodal lymphoma in the treatment of ELSA.

HYPOTHESIS

The purpose of this retrospective, multi-institutional study was to evaluate the efficacy of 1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea (CCNU) in the treatment of ELSA.

ANIMALS

Forty-six dogs with adequate follow-up and treatment response information.

METHODS

All cases were diagnosed histopathologically. Immunohistochemisty (CD3, CD79a) was performed on 42/46 samples.

RESULTS

Presenting skin lesions included generalized scales (25/46), plaques or nodules (22/46), mucocutaneous lesions (14/ 46), and corneal involvement (1/46). Lymph node involvement and Sézary syndrome were documented in 7 and 2 dogs, respectively. The median number of CCNU treatments was 4 (range, 1-11), with a median starting dose of 60 mg/m(2) (range, 30-95). Of the 46 dogs, 15 achieved complete remission, 23 achieved partial remission, 5 had stable disease, and 3 had progressive disease, for an overall response rate of 83%. The median number of treatments to achieve a response was 1 (range, 1-6). The overall median duration of response was 94 days (range, 22-282). Sixteen dose reductions were required because of neutropenia (10/46), thrombocytopenia (1/46), anemia (1/46), increased liver enzyme activity (3/46), or unspecified reasons (1/46).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Given the high response rate and well tolerated protocol, prospective studies are warranted to investigate the utility of CCNU alone or in multi-agent protocols for the treatment of ELSA.

A genetic and environmental analysis of a twin family study of alcohol use, anxiety, and depression

Alcohol consumption, anxiety, and depression were measured by questionnaire in 572 twin families ascertained from the Institute of Psychiatry (London) normal twin register, each family consisting of an adult twin pair, their parents, and siblings--a total of 1,742 individuals. A multivariate normal model for pedigree analysis was applied to each variable, with power transformations fitted to maximise the fit with distributional assumptions. The effect of shared twin environment was estimated by considering the measured cohabitation history of twin pairs. For log-transformed alcohol consumption, amongst current drinkers this effect was the same for MZ and DZ pairs but depended on the cohabitation status of pairs. For both anxiety and depression the effect was clearly not the same for MZ and DZ pairs. Therefore the basic assumption of the classical twin method appears to be invalid for all three traits. Estimates of heritability derived from these analyses were compared with those obtained (1) by applying the classical twin method to twin data only, and (2) by a pedigree analysis ignoring the effect of shared twin environment. For all variables there were considerable differences between estimates based on the three models. This study illustrates that data from twins and their relatives which includes information on cohabitation history might distinguish shared genes and shared environment as causes of familial aggregation. In these behavioral traits the effect of shared twin environment may depend on zygosity and play a major role in explaining familial aggregation in twin family data.

Cardiac troponin I in the normal dog and cat

Cardiac troponin I (cTnI) has proven to be a highly specific and sensitive marker for myocardial cellular damage in many mammalian species. The structure of cTnI is highly conserved across species, and assays for human cTnI (including the one used in the current study) have been validated in the dog. Blood concentrations of cTnI rise rapidly after cardiomyocyte damage, and assay of cTnI potentially may be valuable in many clinical diseases. The purpose of this study was to establish the normal range of cTnI in heparinized plasma of dogs and cats. Forty one clinically normal dogs and 21 cats were included in the study. One to 3 milliliters of blood were collected by venipuncture into lithium heparin vacutainers for analysis of cTnI (Stratusz CS). The range of plasma cTnI concentrations in dogs was <0.03 to 0.07 ng/mL with a mean of 0.02 ng/mL, with the upper tolerance limit (0.07 ng/mL) at the 90th percentile with 95% confidence. In cats, the range was <0.03 to 0.16 ng/mL with a mean of 0.04 ng/mL, and the upper tolerance limit (0.16 ng/mL) at the 90th percentile as well with 90% confidence. This study establishes preliminary normal ranges of plasma cTnI in normal dogs and cats for comparison to dogs and cats with myocardial injury or disease.

Plasma vascular endothelial growth factor concentrations in healthy dogs and dogs with hemangiosarcoma

Vascular endothelial growth factor (VEGF) is a dimeric glycosylated polypeptide growth factor with potent angiogenic, mitogenic, and vascular permeability-enhancing properties specific for endothelial cells. In humans, VEGF seems to play a major role in tumor growth, and plasma concentrations correlate with tumor burden, response to therapy, and disease progression. This study compared plasma VEGF concentrations in healthy client-owned dogs (n = 17) to dogs with hemangiosarcoma (HSA; n 16). Dogs with HSA were significantly more likely to have detectable concentrations of plasma VEGF (13/17) compared to healthy dogs (1/17; P < .001). The median plasma VEGF concentration for dogs with HSA was 17.2 pg/mL (range, < 1.0-66.7 pg/mL). Plasma VEGF concentrations in dogs with HSA did not correlate with stage of disease or tumor burden, but 1 dog had undetectable VEGF during chemotherapy that subsequently increased with disease progression.

Treatment of canine hemangiosarcoma: 2000 and beyond

Canine hemangiosarcoma (HSA) is an aggressive and malignant neoplasia with a grave prognosis. Surgery and chemotherapy have limited success in prolonging survival times and increasing quality of life in dogs with HSA. Advances in medical oncology are resulting in increased survival rates and a better quality of life for veterinary cancer patients. An understanding of mechanisms of metastasis has led to the development of new treatments designed to delay or inhibit tumor spread. Promising new treatment options include novel delivery systems (inhalation or intracavitary chemotherapy); use of immunomodulators such as liposome-encapsulated muramyl tripeptide-phosphatidylethanolamine; antimetastatic agents such as inhibitors of angiogenesis (interferons, thalidomide), matrix metalloproteinase inhibitors, and minocycline; dietary modifications; and gene therapy. Inhibitors of angiogenesis seem to be safe and, unlike conventional chemotherapy, do not induce drug resistance. Although many of the newer approaches are still under development and review, the use of multimodality therapy incorporating innovative treatment modalities may offer the best therapeutic option for dogs affected with HSA.

Primary renal tumours in cats: 19 cases (1992-1998)

A search from databases of four veterinary colleges and one private referral practice between January 1992 and April 1998 provided 20 cases diagnosed with primary renal neoplasia. Review of these cases revealed 19 primary renal tumours, excluding lymphoma. Of the 20 histologically reviewed cases, the diagnosis was amended in eight. There were 13 renal carcinomas (11 tubular and two tubulopapillary), three transitional cell carcinomas, one malignant nephroblastoma, one haemangiosarcoma and one adenoma. The haemangiosarcoma is, to our knowledge, the first reported case of this tumour type as a primary renal tumour in the cat. Most cats were presented for non-specific clinical signs such as anorexia and weight loss. One cat presented with tumour-associated polycythaemia which has not, to our knowledge, been reported previously. The metastatic rate for cats with complete staging was 64%, and 100% for transitional cell carcinomas.

Excitement in an elephant after intravenous administration of atropine

A 28-year-old Asian elephant (Elephas maximus) was anesthetized for cesarean section to remove a dead calf. The elephant was sedated with azaperone, and atropine was administered IV 90 minutes later in preparation for induction of anesthesia with etorphine HCl. Within 1 minute of injection of atropine, the elephant began swaying, kicking, and moving in an agitated manner around the stall. There is considerable variation among species in the toxicity of atropine, although development of toxicosis usually is associated with overdosage.

Alcohol use, smoking habits and the Adult Eysenck Personality Questionnaire in adolescent Australian twins [corrected]

In 1988, questionnaires were received from 1,400 twin pairs (17% MZM, 23% MZF, 17% DZM, 19% DZF, 24% DZO) aged 11 to 18, registered with the Australian NHMRC Twin Registry. Twins reported independently on themselves and on the perceived behaviour of their parents, siblings and friends. For smoking and for drinking in the previous month, the prevalence was modelled as a logistic function of age, sex, perceived smoking or drinking behaviour of family and friends, and the Adult Eysenck Personality Questionnaire (AEPQ) scales. Strengths of association were: family behaviour, odds ratio (OR) < or = 2; Extraversion and Psychoticism, interquartile OR approximately 1.6; behaviour of friend, OR approximately 3 to 6. Twin associations were represented by odds ratios. For smoking they were 16 in MZ and 7 in DZ same-sex pairs, and 3 in DZO pairs. Although the former is consistent with genetic factors determining adolescent smoking behaviour, the reduced association in DZO pairs and strong association with smoking by friends argue to the contrary. For drinking, twin odds ratios were 11 in MZM, MZF and DZF pairs, and 4 in DZM and DZO pairs, consistent with genetic factors determining alcohol use in male but not female, adolescents. Twin odds ratios were not influenced by adjustment for the AEPQ scales; this does not support the hypothesis that genetic factors which determine personality also determine smoking or drinking behaviour during adolescence [corrected].

Where people die in Victoria

OBJECTIVE

To describe where deaths occur in Victoria and to determine to what extent the probability of dying in certain institutions is associated with cause of death and sociodemographic variables.

DESIGN

Descriptive study of death certificates and multivariate analysis of 7697 deaths that occurred in a three-month period in 1988.

SETTING

The State of Victoria.

MAIN OUTCOME MEASURES

Cause of death, age, sex, marital status, and socioeconomic status.

RESULTS

Most deaths occurred in public hospitals (48%) followed by private homes (21%), nursing homes (14%) and private hospitals (9%). Only 2% of all deaths (90% from cancer) occurred in hospices. Women were more likely to die in a nursing home than were men (21% v. 8%) and less likely to die at home (17% v. 24%). The proportion of deaths increased with age in nursing homes and declined in private homes. Significant predictors of death in a public hospital were age and socioeconomic status; the probability diminished with increasing age and was lower for those in the upper third for socioeconomic status. Predictors for dying in a private home were age and marital status; the probability diminished with age and in the absence of a spouse.

CONCLUSIONS

Death as a hospice inpatient is comparatively rare in Victoria and the impact of hospice outpatient or domiciliary care on dying at home has yet to be established. Should death at home become a preferred option, the presence and ability of a spouse or other caregiver will be a significant factor.

Innovations in the statistical analysis of twin studies

Advances in computer technology have made possible a greater sophistication in the statistical analysis of pedigree data, however this is not necessarily manifest by fitting more comprehensive causative models. Planned twin and family studies measure numerous explanatory variables, including perhaps genetic and DNA marker information status on all pedigree members, and the cohabitation of all pairs of individuals. A statistical analysis should examine the contribution of these measured factors on individual means, and in explaining the variation and covariation between individuals, concurrently with the postulated effect of unmeasured factors such as polygenes. We present two models that meet this requirement: the Multivariate Normal Model for Pedigree Analysis for quantitative traits, and a Log-Linear Model for Binary Pedigree Data. For both models, important issues are examination of fit, detection of outlier pedigrees and outlier individuals, and critical examination of the model assumptions. Procedures for fulfilling these needs and examples of modelling are discussed.

Genetic and environmental influences on obsessional traits and symptoms

A biometrical genetic analysis was carried out on the response of 419 pairs of twins to the 42-item version of Leyton Obsessional Inventory. Just under half the variation in both the Obsessional Trait and Symptom Scales was due to heredity. Multivariate analysis revealed a genetic effect on the development of obsessional personality and also the transmission of a general tendency predisposing to neurotic breakdown. Although the influence of heredity was outweighed by that of the environment, the latter effect showed an absence of general factors and, in particular, of any noticeable effect from the common home environment.

Genetics of platelet MAO activity in discordant schizophrenic and normal twins

Platelet monoamine oxidase (MAO) activity was compared in four age and sex-matched groups: monozygotic (MZ) twins discordant for schizophrenia, normal MZ twins, normal dizygotic (DZ) twins and unrelated individuals. Among the twin groups, schizophrenic and normal there was a remarkably consistent degree of genetic control amounting to 70-80 per cent of the variation in activity. The mean platelet MAO activity of the schizophrenic twins was significantly lower than that of controls, but not than that of their psychiatrically well, neuroleptic-free cotwins; indeed the correlation for the MZ twins discordant for schizophrenia was almost exactly the same as that for the normal MZs. Thus, lower platelet MAO activity in schizophrenia, where it is found, is genetically modulated and not the result of the illness or its treatment.

Cerebral ventricular size in twins discordant for schizophrenia

Comparison of the computerised tomographic scans of 11 pairs of healthy monozygotic (MZ) with those of 8 pairs of dizygotic (DZ) twins showed that ventricular size for seven pairs of MZ twins discordant for schizophrenia was not as high as in normal MZ twins. Furthermore, the schizophrenics had significantly larger ventricles than both control twins and their own co-twins, although there was a non-significant trend for their co-twins also to have larger ventricles than the controls. Some common environmental factor, possibly perinatal damage, may have led to the increase in ventricular size in the schizophrenia-discordant pairs, with schizophrenia developing in the more severely affected twin.