Sternohyoid and diaphragm muscle form and function during postnatal development in the rat.

NEW FINDINGS: What is the central question of this study? Co-ordinated activity of the thoracic pump and pharyngeal dilator muscles is critical for maintaining airway calibre and respiratory homeostasis. Whilst postnatal maturation of the diaphragm has been well characterized, surprisingly little is known about the developmental programme in the airway dilator muscles. What is the main finding and its importance? Developmental increases in force-generating capacity and fatigue in the sternohyoid and diaphragm muscles are attributed to a maturational shift in muscle myosin heavy chain phenotype. This maturation is accelerated in the sternohyoid muscle relative to the diaphragm and may have implications for the control of airway calibre in vivo. The striated muscles of breathing, including the thoracic pump and pharyngeal dilator muscles, play a critical role in maintaining respiratory homeostasis. Whilst postnatal maturation of the diaphragm has been well characterized, surprisingly little is known about the developmental programme in airway dilator muscles given that co-ordinated activity of both sets of muscles is needed for the maintenance of airway calibre and effective pulmonary ventilation. The form and function of sternohyoid and diaphragm muscles from Wistar rat pups [postnatal day (PD) 10, 20 and 30] was determined. Isometric contractile and endurance properties were examined in tissue baths containing Krebs solution at 35°C. Myosin heavy chain (MHC) isoform composition was determined using immunofluorescence. Muscle oxidative and glycolytic capacity was assessed by measuring the activities of succinate dehydrogenase and glycerol-3-phosphate dehydrogenase using semi-quantitative histochemistry. Sternohyoid and diaphragm peak isometric force and fatigue increased significantly with postnatal maturation. Developmental myosin disappeared by PD20, whereas MHC2B areal density increased significantly from PD10 to PD30, emerging earlier and to a much greater extent in the sternohyoid muscle. The numerical density of fibres expressing MHC2X and MHC2B increased significantly during development in the sternohyoid. Diaphragm succinate dehydrogenase activity and sternohyoid glycerol-3-phosphate dehydrogenase activity increased significantly with age. Developmental increases in force-generating capacity and fatigue in the sternohyoid and diaphragm muscles are attributed to a postnatal shift in muscle MHC phenotype. The accelerated maturation of the sternohyoid muscle relative to the diaphragm may have implications for the control of airway calibre in vivo.

Chronic hypoxia increases rat diaphragm muscle endurance and sodium-potassium ATPase pump content.

The effects of chronic hypoxia (CH) on respiratory muscle are poorly understood. The aim of the present study was to examine the effects of CH on respiratory muscle structure and function, and to determine whether nitric oxide is implicated in respiratory muscle adaptation to CH. Male Wistar rats were exposed to CH for 1-6 weeks. Sternohyoid and diaphragm muscle contractile properties, muscle fibre type and size, the density of fibres expressing sarco/endoplasmic reticulum calcium-ATPase (SERCA) 2 and sodium-potassium ATPase (Na+,K+-ATPase) pump content were determined. Muscle succinate dehydrogenase (SDH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) dehydrogenase activities were also assessed. Acute and chronic blockade of nitric oxide synthase (NOS) was employed to determine whether or not NO is critically involved in functional remodelling in CH muscles. CH improved diaphragm, but not sternohyoid, fatigue tolerance in a time-dependent fashion. This adaptation was not attributable to increased SDH or NADPH dehydrogenase activities. The areal density of muscle fibres and relative area of fibres expressing SERCA2 were unchanged. Na+,K+-ATPase pump content was significantly increased in CH diaphragm. Chronic NOS inhibition decreased diaphragm Na+,K+-ATPase pump content and prevented CH-induced increase in muscle endurance. This study provides novel insight into the mechanisms involved in CH-induced muscle plasticity. The results may be of relevance to respiratory disorders characterised by CH, such as chronic obstructive pulmonary disease.

Families of manic-depressive patients: effect of treatment.

The authors studied the families of 12 patients with bipolar manic-depressive illness. They measured family stability using a life events scale for a 2-year period before lithium treatment and for 2 years during lithium treatment. The patients responded well to treatment; they were able to resume normal roles within the family. The life events scores decreased substantially during treatment in comparison with before treatment. The most severe impact of the illness was found in the children: 45% (N = 10) were moderately ill or symptomatic. The authors discuss the effect of manic-depressive illness on the family system as a whole and emphasize the need to combine psychosocial treatment with lithium treatment.

Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: a preliminary report.

Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.

Functional brain imaging in the evaluation of psychiatric illness.

In the past century, the field of psychiatry has undergone major changes. During this time, significant advancements in both diagnosis and treatment have occurred. Medical brain imaging using structural and functional brain imaging techniques have contributed, in part, to a better basic understanding of psychiatric disease and to an improving diagnostic approach. Computed tomography and magnetic resonance imaging have supplied limited, but useful insight regarding structural alterations in schizophrenia and the affective disorders. Position emission tomography imaging has already made a major contribution in the assessment of schizophrenia and affective disorders. Single-photon emission computed tomography (SPECT), which is currently more widely available, should contribute more to psychiatric disease evaluation in the future. Recent advances in SPECT technology in the areas of improved instrumentation--such as multidetector and ring detector systems and new radiopharmaceuticals including new rCBF markers and receptor site imaging agents--have contributed to significant improvements in the SPECT imaging technique. At the present time, SPECT has been shown to be feasible and useful in the evaluation of acute and chronic psychiatric and demented states. As SPECT technology continues to evolve, further refinements in this diagnostic capability can be anticipated.

PDQ-R personality disorders in bipolar patients.

The prevalence of personality traits and disorders in bipolar patients as reported in the literature varies widely. The Personality Diagnostic Questionnaire-Revised (PDQ-R) is a self-report instrument for DSM-IIIR personality disorders found to have validity, but with high sensitivity and moderate specificity. This study was designed to assess personality disorders in bipolar patients using the PDQ-R. Fifty bipolar patients in a long-term lithium treatment program completed the PDQ-R. Over one half the patients (58%) scored for one or more personality disorders. A total of 71 diagnoses was made among the 50 patients, or a mean of 1.42 per patient. The majority of the axis II diagnoses were from cluster B, with borderline the most prevalent, followed by histrionic. The PDQ-R has high sensitivity but moderate specificity and may overdiagnose personality disorders in bipolar patients. The PDQ-R may register subclinical aspects of affective disorder as personality.

The role of SPECT brain imaging in assessing psychopathology in the medically ill.

Cerebral single photon emission computed tomography (SPECT), a method of functional brain imaging, measures cerebral blood flow and metabolism. This paper describes the imaging procedure and several cases where cerebral SPECT was of use in the differential diagnosis of medically ill patients who also presented with psychopathology. SPECT patterns in cerebrovascular disease, dementia, focal epilepsy, and AIDS are at present the best described and seem to be the most specific. Often changes in regional cerebral blood flow are seen before structural changes become apparent on CT or MRI. Cerebral SPECT can add valuable diagnostic information in assessing psychopathology in the medically ill and can often lead to changes in treatment.

Single-photon emission computed tomography of the brain in acute mania and schizophrenia.

Single-photon emission computed tomography (SPECT) imaging with n-isopropyliodoamphetamine (IMP) was performed on 11 patients with bipolar mania, 21 acute schizophrenics, and 15 healthy control subjects. Subjects were evaluated with neuropsychological tests and psychiatric rating scales. SPECT brain studies were blindly evaluated to assess the degree of radiopharmaceutical uptake in three neuroanatomical regions of interest in each hemisphere. All the control subjects, 1 manic patient, and 1 schizophrenic patient had normal brain SPECT uptake patterns. The scans of all others were read as abnormal. Hypofrontality was noted in some schizophrenics and maniacs. A significant increase in tracer uptake in temporal lobes was observed in both patient groups, more prominently in the manic patients. Increased and decreased basal ganglia uptake was also observed in patients. Both manic and schizophrenic patients showed cortical tracer heterogeneity of varying degree. The patterns of cerebral SPECT uptake seen in these acute psychoses were not specific for a diagnosis, but may be associated with dimensions of psychopathology. Because the patterns are different from those seen in cerebrovascular disease and the dementias, they may prove to be helpful in differential diagnosis.

The potential value of serial cerebral SPECT scanning in the evaluation of psychiatric illness.

Cerebral SPECT imaging has the potential to make an important contribution to clinical psychiatry. Cerebral SPECT scanning, stimulated by the work with PET, is readily available and much less expensive than PET. This paper reports a case demonstrating the potential value of cerebral SPECT scanning with I-123 IMP, specifically in the serial evaluation of a schizophrenic patient with auditory hallucinations. The initial scan revealed focal areas of increased uptake in the caudate nuclei of the basal ganglia, and in the right temporal lobe. After pharmacological treatment with clinical improvement, the follow-up SPECT scan demonstrated significant improvement in the distribution of the radiopharmaceutical.

A review of the use of electroconvulsive therapy.

ECT is an effective psychiatric treatment for severe depression, mania, catatonic states, and, to a lesser degree, some schizophrenias. Complications are minimal and the risk of death extremely low, lower than that for an inadequately treated depression. However, some medical centers in the United States do not use ECT at all. The neurochemical mechanisms that underlie ECT remain unknown, but a cerebral seizure is essential. The average number of treatments is seven, spread over two to three weeks. All candidates for ECT should undergo a complete medical evaluation and give informed consent.

The role of social factors in affective disorders: a review.

A number of researchers, dissatisfied with traditional models of affective illness, have developed multidimensional systems models that more accurately reflect how genetic, biological, and social factors may interact to increase vulnerability or resilience to stressors and illness. The role of five social factors in this process--demographics, early childhood experiences, life events, social support, and families--is reviewed. Serious methodologic difficulties hamper the study of social factors in affective illness, prompting the authors to suggest that researchers develop a new research paradigm that attempts not only to quantify social factors but to understand their meaning to the individual.

Characteristics of HIV-infected patients in an inpatient psychiatric setting.

Psychiatric admissions of patients infected with the human immunodeficiency virus (HIV) over a 5-year period (1986-1991) are reviewed. Ninety-one patients were studied. Suicidal thoughts/attempt was the most common reason for hospital admission. The two most common diagnostic categories were 1) organic mental syndrome, and 2) substance abuse/dependence. Forty-five percent of the patients either initiated their discharges or drastically improved without the use of psychotropic medications. The authors suggest that outpatient psychiatric facilities can provide psychiatric care for HIV-infected patients seeking it.

Outcome of bipolar disorder on long-term treatment with lithium.

The long-term treatment outcome of 248 bipolar patients in an out-patient lithium programme was assessed. Over half of the patients (138 or 56%) had no affective episodes in the year observed. Patients were divided into outcome groups according to GAS scores: the outcome for 40% of patients was good, for 41% fair, and for 19% poor. More frequent psychiatric admissions before starting lithium treatment was the best predictor of poor outcome, followed by a negative affective style in the family and lower social class. Current alcohol and drug abuse was associated with poor outcome. Although familial and psychosocial factors were significantly associated with outcome, the findings suggest there may be inherent differences in the pathophysiology of bipolar disorder reflected in an increased frequency of episodes which account for a large variance in lithium treatment outcome.

Social support and long-term lithium outcome.

The failure rate in long-term lithium treatment of bipolar affective disorder is in the range of 20 to 30%, even with rigorous diagnostic criteria an adequate serum lithium levels. This may be due to a variety of biologic and psychosocial factors. Psychosocial factors affecting treatment outcome were studied in 60 RDC diagnosed bipolar patients treated with lithium for one year. Outcome was measured using an affective episode score, a social adjustment scale and a global assessment scale. Social support was the factor most strongly correlated with a good outcome on all three measures.

Single photon emission computed tomography (SPECT) with [123I]IMP in the differential diagnosis of psychiatric disorders.

Single photon emission computed tomography (SPECT) with [123I]N-isopropyl iodoamphetamine--[123I]IMP--was used to study regional cerebral blood flow (rCBF) in 94 psychiatric patients and six controls. Patients with dementias had distinct brain-image patterns, consistent with the expected neuropathology. Major depressives had decreased cortical and subcortical rCBF. Increased caudate rCBF was observed in schizophrenics and other psychoses with positive symptoms. SPECT is a practical method of functional brain imaging with potential in the differential diagnosis of neuropsychiatric disorders. Further studies are needed to assess the effect of other variables on brain-image patterns.