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K McKenna

Publications and source records attributed to K McKenna.

At least 19 recordsLinked to original sources
PubMed2000

Neuropsychological deficits in pediatric patients with childhood-onset schizophrenia and psychotic disorder not otherwise specified.

OBJECTIVE: Children with transient psychotic symptoms and serious emotional disturbances who do not meet current criteria for schizophrenia or other presently recognized diagnostic categories commonly present diagnostic and treatment problems. Clarifying the connections between children with narrowly defined schizophrenia and children with a more broadly defined phenotype (i.e., Psychotic Disorder Not Otherwise Specified, PD-NOS) has implications for understanding the pathophysiology of schizophrenia. In this study, the neuropsychological test performance of a subgroup of children with atypical psychosis was compared with that of patients with childhood-onset schizophrenia (COS). METHOD: Cognitive function was assessed with neuropsychological test battery regimens in 51 neuroleptic-nonresponsive patients within the first 270 at NIMH testing (24 PD-NOS, 27 COS) were included in this analysis. Seventeen (39%) of 44 COS subjects were unavailable for this study as their IQ tested <70. The PD-NOS patients were younger than the COS patients at the time of testing (12.0+/-2.8 vs 14.4+/-1.8years, respectively, p<0.004). The test levels of these groups were compared with each other. RESULTS: The neuropsychological test results for the PD-NOS and COS patients were 1-2standard deviations below normative data across a broad array of cognitive functions. There were no overall differences in the test levels for the six summary scales (F=2.82, df=1, 36, p=0.10) or in the profile shape (F=1.70, df=5, 180, p=0.14) between the PD-NOS and COS groups. For the COS patients, there was a significant difference between their mean full-scale WISC IQ (84.7+/-16.2) and their average standard scores for both the spelling (97.7+/-16.1, n=23, t=4.0, p=0.001) and reading decoding subtests (97.7+/-13.7, n=23, t=3.7, p=0.001) of the Kaufman Test of Educational Achievement. CONCLUSIONS: Treatment-refractory PD-NOS and COS patients share a similar pattern of generalized cognitive deficits, including deficits in attention, learning and abstraction which are commonly observed in adult patients with schizophrenia. These data support a hypothesis that at least some of the PD-NOS cases belong within the schizophrenic spectrum, which is of importance for future genetic studies planned for this cohort.

Adolescent↗
PubMed2000

Hyponatraemia.

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Adult↗
PubMed2000

Angiotensin-converting enzyme inhibition by quinapril blocks the albuminuric effect of atrial natriuretic peptide in Type 1 diabetes and microalbuminuria.

AIMS: This study examined the effect of angiotensin-converting enzyme inhibition, administered at doses with no effect on systemic blood pressure, on the albuminuric action of atrial natriuretic peptide (ANP). METHODS: Seven Type 1 diabetic patients with established microalbuminuria participated in a two limb, single-blind, placebo controlled study. Subjects were administered quinapril 10 mg daily or placebo for 7 days prior to study. On the study day, subjects were euglycaemic clamped and subsequently fluid loaded (20 ml/kg tap water orally plus urinary losses). At steady state diuresis, a 1 h intravenous infusion of ANP 0.05 mg.kg(-1) x min(-1) was administered. Urine was collected at 15-min intervals for estimation of albumin-creatinine ratio (ACR). Results were analysed by ANOVA. RESULTS: Baseline mean arterial pressure was similar after pre-treatment with quinapril and placebo (98.7 +/- 3.8 vs. 100 +/- 4.5 mmHg, mean +/- SD, P > 0.5), and was unaltered by ANP infusion on either study day. Baseline ACR was similar on quinapril and placebo (P = 0.13). ANP infusion induced a rise in urine ACR with placebo (58.4 +/- 40.2 to 393.6 +/- 262.9 mg/mmol, P = 0.006), but not with quinapril (29.3 +/- 10.7 to 81.5 +/- 43 mg/mmol, P = 0.15). The urine ACR response to ANP infusion was higher with placebo than with quinapril (P = 0.02). CONCLUSIONS: Quinapril blocks the albuminuric effect of intravenous infusion of ANP in subjects with Type 1 diabetes mellitus and established microalbuminuria. This action is independent of changes in mean arterial pressure and creatinine clearance.

Albuminuria↗
PubMed2000

Enhanced albuminuric response to atrial natriuretic peptide in normoalbuminuric patients with Type 1 diabetes mellitus--a pilot study.

AIMS: To ascertain whether intravenous infusion of atrial natriuretic peptide (ANP) can induce microalbuminuria in patients with Type 1 diabetes mellitus (DM), as already demonstrated in patients with microalbuminuria, and to compare the albuminuric response to ANP infusion in Type 1 DM and a matched group of healthy non-diabetic controls. METHODS: Eight normoalbuminuric DM patients participated in a three limb, randomized, double-blind, placebo-controlled study. Subjects were kept euglycaemic by insulin infusion, and subsequently water-loaded (20 ml/kg orally plus urinary losses). When in steady state, a 30-min infusion of either placebo, ANP 0.025 mg x kg(-1).min(-1) or ANP 0.05 mg x kg(-1) x min(-1) was administered intravenously. Urine was collected every 15 min for 90 min for the estimation of albumin-creatinine ratio (ACR). In addition, eight nondiabetic volunteers received a single infusion of ANP 0.025 mg x kg(-1) x min(-1). RESULTS: ACR was unaltered by placebo in DM subjects (1.4 +/- 0.7-1.7 +/- 1.1 mg/mmol, mean +/- SD, ANOVA, P > 0.9), and by low dose ANP in controls (1.4 +/- 0.9-2.6 +/- 1.9 mg/mmol, P = 0.4). ACR increased with low dose ANP (1.3 +/- 0.5-14.6 +/- 13.6 mg/mmol, P = 0.02), and high dose ANP (1.3 +/- 0.7-26.4 +/- 31 mg/mmol, P = 0.01) in DM subjects. The ACR response to low dose ANP was greater in the DM than control subjects (P = 0.02). CONCLUSIONS: ANP increases urine albumin excretion rate in normoalbuminuric Type 1 DM patients, and this effect is more pronounced than in healthy volunteers.

Adult↗
PubMed2000

Acute hyperglycaemia causes elevation in plasma atrial natriuretic peptide concentrations in Type 1 diabetes mellitus.

AIMS: To examine the effect of acute hyperglycaemia on atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations in Type 1 diabetes. METHODS: The study was two limb, randomized, and single-blind. Eight Type 1 diabetes subjects were clamped at euglycaemia by intravenous infusion of insulin. When euglycaemia was established, the insulin infusion rate was left unaltered for the remainder of the protocol, and an intravenous infusion of either 500 ml 0.9% saline or 500 ml 10% dextrose was administered over 1 h. Blood was collected for estimation of plasma glucose, ANP and BNP concentrations at 30 min intervals for 2 h from the start of the infusion period. One week later, each subject received the alternate infusion. Results are expressed as mean +/- standard deviation, and were analysed by ANOVA. RESULTS: Baseline plasma glucose (P = 0.8), ANP (P = 0.8) and BNP (P = 0.8) concentrations were similar on the study days. Plasma glucose rose with dextrose (6.1 + 0.5-15.1 + 2.8 mmol/l, P = 0.9). Plasma ANP concentrations were unaltered by saline infusion (76.5 +/- 14.7-77.7 +/- 15.2 pg/ml, P = 0.9), but increased with dextrose infusion (79 +/- 14-134 +/- 17.1 pg/ml, P < 0.0001), and were higher with dextrose than saline infusion (P < 0.0001). Plasma concentrations of BNP were not significantly altered by infusion of either dextrose (5.1 +/- 3.9-9.3 +/- 5.4 pg/ml, P = 0.63) or saline (4.3 +/- 3.5-6 +/- 5.2 pg/ml, P = 0.84). CONCLUSIONS: Plasma concentrations of ANP, but not BNP, rise in response to acute hyperglycaemia in Type 1 diabetes.

Adult↗
PubMed2000

Sexual harassment: everyday violence in the lives of girls and women.

Sexual harassment is one of the most insidious, yet pervasive, forms of violence that affects all girls, not merely those traditionally thought to be vulnerable or at risk. Although harassment in the workplace has been the focus of considerable attention during the last decade, there is a growing recognition that girls experience varied forms of sexual harassment, and that this behavior begins at a surprisingly early age. This article examines the plight of the "girl child" and presents findings from the first phase of a national action research project currently being conducted by the Canadian Alliance of Five Research Centres on Violence. A major objective of this project is to examine how violence becomes "normalized" in the lives of girls and young women. Implications for nurses, including strategies aimed at encouraging resistance among this population, are addressed.

Adolescent↗
PubMed2000

Renal resistance to vasopressin in poorly controlled type 1 diabetes mellitus.

To investigate the hypothesis that diabetes induces nephrogenic diabetes insipidus, we studied the urine-concentrating ability in response to vasopressin (AVP) in 12 patients with insulin-dependent diabetes mellitus (IDDM) and 12 nondiabetic controls. Subjects were euglycemic-clamped, and after oral water loading, AVP was infused intravenously for 150 min. AVP induced a greater (P<0.001) rise in urine osmolality in controls (67.6+/-10.7 to 720+/-31.1 mosmol/kg, P<0.001) than in IDDM patients (64.3+/-21.6 to 516.7+/-89.3 mosmol/kg, P<0.001). Urinary aquaporin-2 concentrations after AVP infusion were higher in controls (611.8+/-105.6 fmol/mg creatinine) than in IDDM (462.0+/-94.9 fmol/mg creatinine, P = 0. 003). Maximum urine osmolality in IDDM was inversely related to chronic blood glucose control, as indicated by Hb A(Ic) (r = -0.87, P = 0.002). To test the hypothesis that improved glycemic control could reverse resistance to AVP, 10 IDDM subjects with poor glycemic control (Hb A(Ic) >9%) were studied before (B) and after (A) intensified glycemic control. Maximum urine osmolality in response to AVP increased with improved glycemic control (B, 443.8+/-49.0; A, 640.0+/-137.2 mosmol/kg, P<0.001), and urinary aquaporin-2 concentrations after AVP increased from 112.7 +/-69 to 375+/-280 fmol/mg creatinine (P = 0.006), with improved glycemic control. Poorly controlled IDDM is associated with reversible renal resistance to AVP.

Adolescent↗
PubMed2000

Childhood-onset psychotic disorders: magnetic resonance imaging of volumetric differences in brain structure.

OBJECTIVE: Although childhood-onset schizophrenia is rare, children with brief psychotic symptoms and prominent emotional disturbances commonly present diagnostic and treatment problems. Quantitative anatomic brain magnetic resonance images (MRIs) of a subgroup of children with psychotic disorder not otherwise specified were compared with those of children with childhood-onset schizophrenia and healthy comparison subjects. METHOD: Anatomic MRIs were obtained for 71 patients (44 with childhood-onset schizophrenia and 27 with psychotic disorder not otherwise specified) and 106 healthy volunteers. Most patients had been treated with neuroleptics. Volumetric measurements for the cerebrum, anterior frontal region, lateral ventricles, corpus callosum, caudate, putamen, globus pallidus, and midsagittal thalamic area were obtained. RESULTS: Patients had a smaller total cerebral volume than healthy comparison subjects. Analysis of covariance for total cerebral volume and age found that lateral ventricles were larger in both patient groups than in healthy comparison subjects and that schizophrenia patients had a smaller midsagittal thalamic area than both subjects with psychotic disorder not otherwise specified and healthy comparison subjects. CONCLUSIONS: Pediatric patients with psychotic disorder not otherwise specified showed a pattern of brain volumes similar to those found in childhood-onset schizophrenia. Neither group showed a decrease in volumes of temporal lobe structures. Prospective longitudinal magnetic resonance imaging and clinical follow-up studies of both groups are currently underway to further validate the distinction between these two disorders.

Adolescent↗
PubMed1999

Exaggerated vasopressin secretion and attenuated osmoregulated thirst in human survivors of hyperosmolar coma.

AIMS/HYPOTHESIS: To test the hypothesis that subnormal thirst sensation could contribute to the development of the hypernatraemia characteristic of hyperosmolar coma, we studied osmoregulation in survivors of hyperosmolar coma. METHODS: Eight survivors of hyperosmolar coma, eight control subjects with Type II (non-insulin-dependent) diabetes mellitus and eight healthy control subjects underwent water deprivation during which measurements of thirst, plasma osmolality and vasopressin were taken. RESULTS: Water deprivation caused greater peak plasma osmolality in the hyperosmolar coma group (301.7 +/- 2.7 mmol/kg) than in Type II diabetic (294.3 +/- 3.2 mmol/kg, p < 0.01) or control group (296.9 +/- 3.0 mmol/kg, p < 0.01) and a greater increase in plasma vasopressin concentration (hyperosmolar coma, 5.8 +/- 1.3 pmol/l, Type II diabetes, 1.8 +/- 1.3 pmol/l, p < 0.001, control subjects, 2.2 +/- 1.8 pmol/l, p < 0.001). Thirst ratings were lower following water deprivation in the hyperosmolar coma group (3.5 +/- 0.8 cm) than in Type II diabetes (7.7 +/- 1.6 cm, p < 0.001) or control subjects (7.4 +/- 1.3 cm, p <0.001), and the hyperosmolar group patients drank less in 30 min following water deprivation (401 +/- 105 ml) than Type II diabetic (856 +/- 218 ml, p < 0.001) or control subjects (789 +/- 213 ml, p < 0.001). CONCLUSION/INTERPRETATION: Survivors of hyperosmolar coma have subnormal osmoregulated thirst and fluid intake, which might contribute to the hypernatraemic dehydration typical of the condition.

Aged↗
PubMed1999

Vocational outcome following spinal cord injury.

STUDY DESIGN: Non-experimental (ex post facto) survey research design involving the use of a fixed alternative format questionnaire. OBJECTIVES: To investigate variables influencing vocational outcome, to identify barriers to gaining and sustaining employment and to identify the effects of variables on the type of work engaged in following spinal cord injury. The two sets of independent variables considered were, individual and injury-related factors (age at onset of injury, time since injury, extent/level of injury, highest educational qualification achieved pre-injury, and pre-injury occupation) and circumstantial factors (means of transport, access difficulties, perceived workplace discrimination, financial disincentives to work and perceived level of skill). SETTING: The Princess Alexandra Hospital Spinal Injuries Unit, Queensland, Australia. METHODS: Data on the variables and the vocational outcomes of having ever worked or studied post-injury, current employment status and post-injury occupation were obtained from survey responses. Demographical and medical data were gathered from medical records. RESULTS: Forward stepwise logistic regression revealed that having ever worked or studied post-injury was associated with all individual and injury-related factors except pre-injury occupation, and two circumstantial factors, namely means of transport and access difficulties. Current employment was associated with all circumstantial factors as well as age at injury and pre-injury occupation. Standard multiple regression analyses revealed that post-injury occupation was correlated with all individual and injury-related factors as well as means of transport and perceived workplace discrimination. CONCLUSIONS: Tailored rehabilitation programs for individuals with characteristics associated with less successful vocational outcomes may facilitate their employment status after injury.

Adolescent↗
PubMed1999

Reasons for variability in the reported rate of occurrence of unilateral spatial neglect after stroke.

BACKGROUND AND PURPOSE: We sought to determine the frequency of occurrence of contralesional unilateral spatial neglect (USN) after stroke and to investigate the effect of side of lesion, nature of assessment tool used, and timing of assessment relative to stroke onset. METHODS: We performed a systematic review of published reports, identified by a search of electronic databases (MEDLINE 1966-1997, PSYCHLIT 1974-1996, and CINAHL 1982-1997) and by searching reference lists of the reports selected. Excluded were unpublished, non-English language, and nonhuman studies. RESULTS: Thirty published reports met the selection criteria, 17 of which directly compared right brain damage (RBD) and left brain damage (LBD). Contralesional USN appeared to occur more frequently after RBD than LBD in 16 of these. Both the assessment tool used and the time of assessment relative to stroke onset affected the reported rate of occurrence, although recovery rate data were inadequate (4 reports). CONCLUSIONS: The clinical belief that USN occurs more frequently after RBD than LBD was apparently supported by a systematic review of published data. However, an accurate estimate of the rates of occurrence and recovery after stroke could not be derived. Four reasons for the variability among studies were discussed, including subject selection, lesion localization, and nature and timing of assessment. Different USN disorders may exist, which may require type-specific rehabilitation approaches. This may have implications for epidemiological studies and for the development of new treatments. Theoretically driven epidemiological studies are required before adequately powered randomized controlled trials of rehabilitation can be conducted.

Aged↗
PubMed1998

Attention deficits in childhood-onset schizophrenia: reaction time studies.

The hypothesis of continuity between childhood-onset and adult schizophrenia was tested by comparing the performance of 15 patients with childhood-onset schizophrenia and 52 age-matched controls on 2 reaction time paradigms that have been used to study adult schizophrenia. On simple reaction time to tones with regular and irregular preparatory intervals of 2, 4, and 8 s, patients showed greater effects of the length of the preparatory interval in the regular condition and greater effects of the preparatory interval (girls only) and the preceding preparatory interval in the irregular series. On simple reaction time to random lights and tones, patients were faster on ipsimodal sequences than cross-modal sequences compared with controls. Overall, patients were much slower than controls in both paradigms. The results suggest similar attention dysfunction as is found in adult schizophrenia and thus are consistent with the continuity hypothesis.

Adolescent↗
PubMed1998

"Multidimensionally impaired disorder": is it a variant of very early-onset schizophrenia?

OBJECTIVE: To examine the validity of diagnostic criteria for a subgroup of children with atypical psychosis (n = 19), designated here as "multidimensionally impaired." These children are characterized by poor attention and impulse control, psychotic symptoms, and poor affective control. METHOD: Children and adolescents (n = 19) meeting our criteria for multidimensionally impaired syndrome with onset of psychotic symptoms at or before age 12 years were identified from a total of 150 in-person screenings for very early-onset schizophrenia between 1990 and 1996. We compared the premorbid adjustment, family history, follow-up status, and laboratory measures for a subgroup of these children with those of (1) a rigorously defined group of 29 children with DSM-III-R schizophrenia and (2) 19 children with attention-deficit hyperactivity disorder. RESULTS: Patients with multidimensionally impaired syndrome and patients with very early-onset schizophrenia shared a similar pattern of early transient autistic features, postpsychotic cognitive decline, and an elevated risk of schizophrenic-spectrum disorders among their first-degree relatives. This pattern was not seen in the attention-deficit hyperactivity disorder group. In contrast to very early-onset schizophrenia, the multidimensionally impaired group had significantly poorer scores on the Freedom From Distractibility factor on the WISC-R, a less deviant pattern of autonomic reactivity, and no progression to schizophrenia. CONCLUSIONS: The findings support the distinction of the multidimensionally impaired cases as separate from those with other psychiatric disorders, and there is somewhat greater evidence to suggest that this disorder belongs in the schizophrenia spectrum.

Adolescent↗
PubMed1998

Osmoregulation in clinical disorders of thirst appreciation.

Thirst and drinking are essential components of normal osmoregulation in healthy man. Abnormalities of thirst appreciation, in particular hypodipsia, have profound implications for water homeostasis. The combination of cranial diabetes insipidus and hypodipsia can have particularly serious consequences, with the potential for life-threatening hyponatraemia. Although the tools for measuring thirst are subjective and lack true specificity, their use in clinical research has contributed greatly to our understanding of the physiology of thirst appreciation and the abnormal control of thirst in osmoregulatory disorders. The precise neural control of thirst appreciation remains unknown, and perhaps as a result of this, satisfactory therapies for the treatment of disorders of thirst have not yet been developed; behavioural modification and retraining of drinking habits remain the rather limited cornerstones of management.

Adult↗
PubMed1997

Cerebral glucose metabolism in childhood onset schizophrenia.

Decreased frontal cortical glucose metabolism has been demonstrated in adult schizophrenics both at rest and while engaging in tasks that normally increase frontal metabolism, such as the Continuous Performance Test (CPT). The authors tested the hypothesis that adolescents with childhood onset schizophrenia would also demonstrate hypofrontality while performing the CPT. Cerebral glucose metabolism was examined in 16 adolescents (mean age 14.1 +/- 1.7) with onset of schizophrenia by age 12 (mean age at onset 9.9 +/- 1.8) and 26 healthy adolescents selected to be similar in age, sex and handedness using positron emission tomography and 18F-fluorodeoxyglucose. Patients with childhood onset schizophrenia made fewer correct and more incorrect identifications on the CPT. Region of interest analysis revealed no significant group differences in global cerebral glucose metabolism, but increased metabolic rate in supramarginal gyrus (F = 6.74, P < 0.05) and inferior frontal gyrus/insula (F = 7.09, P < 0.05) and decreased metabolic rate in middle frontal gyrus (F = 6.72, P < 0.05) and superior frontal gyrus (t = 2.04, P < 0.05) in schizophrenics. Comparison of effect sizes with an identically designed study of adult schizophrenics did not indicate more severe hypofrontality in childhood onset schizophrenia. Pixel-based analyses indicated a more complex pattern of group differences in cerebral metabolism with bilaterally increased cerebellar metabolic rate in childhood onset schizophrenics. These findings suggest that childhood onset schizophrenia may be associated with a similar, but not more severe, degree of hypofrontality relative to that seen in adult onset schizophrenia.

Adolescent↗
PubMed1997

Pubertal development and onset of psychosis in childhood onset schizophrenia.

In this study, pubertal development was examined for a sample of children and adolescents with childhood onset schizophrenia (COS) defined as psychosis by age 12. Developmental and psychiatric histories were obtained for 28 adolescents (mean age 14.5 +/- 2.3 years) with severe, treatment refractory COS (14 males, 14 females). Age of onset of psychosis was also examined in relation to menarche and development of secondary sex characteristics. Girls had a trend towards developing secondary sex characteristics earlier than boys (P = 0.06), consistent with North American norms. Males (N = 14) and females (N = 14) had similar age of onset of psychosis. The age of development of secondary sex characteristics was associated with onset of psychosis for girls, but this finding was driven by one outlier. There was no significant correlation between development of psychosis and menarche. Neither male nor female probands differed significantly from their well siblings or from North American norms in their age of onset of pubertal development. There was no evidence of early onset of secondary sex characteristics for this sample. Finally, there was an absence of a clear relationship between onset of psychosis and indices of sexual development for these very early onset cases.

Adolescent↗