High ploidy large cytoplasmic megakaryocytes are hematopoietic stem cells regulators and essential for platelet production

Megakaryocytes (MK) generate platelets. Recently, we and others, have reported MK also regulate hematopoietic stem cells (HSC). Here we show high ploidy large cytoplasmic megakaryocytes (LCM) are critical negative regulators of HSC and critical for platelet formation. Using a mouse knockout model (Pf4-Srsf3^Δ/Δ) with normal MK numbers, but essentially devoid of LCM, we demonstrate a pronounced increase in BM HSC concurrent with endogenous mobilization and extramedullary hematopoiesis. Severe thrombocytopenia is observed in animals with diminished LCM, although there is no change in MK ploidy distribution, uncoupling endoreduplication and platelet production. When HSC isolated from a microenvironment essentially devoid of LCM reconstitute hematopoiesis in lethally irradiated mice, the absence of LCM increases HSC in BM, blood and spleen, and the recapitulation of thrombocytopenia. In contrast, following a competitive transplant using minimal numbers of WT HSC together with HSC from a microenvironment with diminished LCM, sufficient WT HSC-generated LCM regulates a normal HSC pool and prevents thrombocytopenia. Importantly, LCM are conserved in humans.

Evaluation of altered environmental conditions as a decontamination approach for SARS-CoV-2 when applied to aircraft related materials

AIMS

The purpose of this study was to evaluate the effects of altered environmental conditions, specifically elevated temperature at various levels of expected relative humidity (RH), on the inactivation of SARS-CoV-2 when applied to U.S. Air Force aircraft materials.

METHODS AND RESULTS

SARS CoV-2 (USA-WA1/2020) was spiked (approximately 1×105 TCID50) in either synthetic saliva or lung fluid, dried onto porous (e.g., Nylon strap) and nonporous materials (e.g., bare aluminum, silicone, and ABS plastic), placed in a test chamber and exposed to environmental conditions ranging from 40-51.7°C and RH ranging from 0-50%. The amount of infectious SARS-CoV-2 was then assessed at various timepoints from 0-2 days. Warmer test temperatures, higher RH, and longer exposure duration resulted in higher inactivation rates per material type. Synthetic saliva inoculation vehicle was more readily decontaminated compared to materials inoculated with synthetic lung fluid.

CONCLUSIONS

SARS-CoV-2 was readily inactivated below limit of quantitation (LOQ) for all materials inoculated using synthetic saliva vehicle within 6 hours when exposed to environmental conditions of 51.7°C and RH ≥ 25%. Synthetic lung fluid vehicle did not follow the general trend of an increase in RH resulting in increased efficacy. The lung fluid performed best at the 20-25% RH range to achieve complete inactivation below LOQ.

The RNA-binding protein SRSF3 has an essential role in megakaryocyte maturation and platelet production

RNA processing is increasingly recognized as a critical control point in the regulation of different hematopoietic lineages including megakaryocytes responsible for the production of platelets. Platelets are anucleate cytoplasts that contain a rich repertoire of RNAs encoding proteins with essential platelet functions derived from the parent megakaryocyte. It is largely unknown how RNA binding proteins contribute to the development and functions of megakaryocytes and platelets. We show that serine-arginine-rich splicing factor 3 (SRSF3) is essential for megakaryocyte maturation and generation of functional platelets. Megakaryocyte-specific deletion of Srsf3 in mice led to macrothrombocytopenia characterized by megakaryocyte maturation arrest, dramatically reduced platelet counts, and abnormally large functionally compromised platelets. SRSF3 deficient megakaryocytes failed to reprogram their transcriptome during maturation and to load platelets with RNAs required for normal platelet function. SRSF3 depletion led to nuclear accumulation of megakaryocyte mRNAs, demonstrating that SRSF3 deploys similar RNA regulatory mechanisms in megakaryocytes as in other cell types. Our study further suggests that SRSF3 plays a role in sorting cytoplasmic megakaryocyte RNAs into platelets and demonstrates how SRSF3-mediated RNA processing forms a central part of megakaryocyte gene regulation. Understanding SRSF3 functions in megakaryocytes and platelets provides key insights into normal thrombopoiesis and platelet pathologies as SRSF3 RNA targets in megakaryocytes are associated with platelet diseases.

Nicotinamide riboside attenuates age-associated metabolic and functional changes in hematopoietic stem cells

With age, hematopoietic stem cells (HSC) undergo changes in function, including reduced regenerative potential and loss of quiescence, which is accompanied by a significant expansion of the stem cell pool that can lead to haematological disorders. Elevated metabolic activity has been implicated in driving the HSC ageing phenotype. Here we show that nicotinamide riboside (NR), a form of vitamin B3, restores youthful metabolic capacity by modifying mitochondrial function in multiple ways including reduced expression of nuclear encoded metabolic pathway genes, damping of mitochondrial stress and a decrease in mitochondrial mass and network-size. Metabolic restoration is dependent on continuous NR supplementation and accompanied by a shift of the aged transcriptome towards the young HSC state, more youthful bone marrow cellular composition and an improved regenerative capacity in a transplant setting. Consequently, NR administration could support healthy ageing by re-establishing a more youthful hematopoietic system.

An evaluation of contaminated estuarine sites using sediment quality guidelines and ecological assessment methodologies

Toxic contaminants may enter estuarine ecosystems through a variety of pathways. When sediment contaminant levels become sufficiently high, they may impact resident biota. One approach to predict sediment-associated toxicity in estuarine ecosystems involves the use of sediment quality guidelines (ERMs, ERLs) and site-specific contaminant chemistry while a second approach utilizes site-specific ecological sampling to assess impacts at the population or community level. The goal of this study was to utilize an integrated approach including chemical contaminant analysis, sediment quality guidelines and grass shrimp population monitoring to evaluate the impact of contaminants from industrial sources. Three impacted sites and one reference site were selected for study. Grass shrimp populations were sampled using a push-netting approach. Sediment samples were collected at each site and analyzed for metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Contaminant levels were then compared to sediment quality guidelines. In general, grass shrimp population densities at the sites decreased as the ERM quotients increased. Grass shrimp densities were significantly reduced at the impacted site that had an ERM exceedance for chromium and the highest Mean ERM quotient. Regression analysis indicated that sediment chromium concentrations were negatively correlated with grass shrimp density. Grass shrimp size was reduced at two sites with intermediate levels of contamination. These findings support the use of both sediment quality guidelines and site-specific population monitoring to evaluate the impacts of sediment-associated contaminants in estuarine systems.

Risk management: how doctors, hospitals and MDOs can limit the costs of malpractice litigation

The concerns of doctors regarding their risk of malpractice litigation and the costs of indemnity premiums are resulting in calls for legal reforms to limit their liability. We do not believe these returns will be successful either practically or politically. Medical defence organisations often attempt to vindicate the doctor rather than settle the dispute--a strategy that might be morally satisfying to doctors but which is also more expensive than the approach taken by commercial insurers. Risk management--the activities required to minimise financial loss for hospitals and the doctors who work in them--is disorganised or absent in most hospitals. Hospital managers lack incentives for risk management because the costs of litigation do not come out of their budgets. The five mainstays of effective risk management are credentialling of medical staff, incident monitoring and tracking, complaints monitoring and tracking, infection control, and documentation in the medical record. The implementation of risk management activities in hospitals is the immediate responsibility of hospital management, not doctors.

Evidence for the segregation of a major gene for human plasma GABA levels

Gamma-aminobutryic acid (GABA) is a major neurotransmitter in the central nervous system, and plasma levels of GABA may reflect brain GABA activity. In 35-40% of patients with mood disorders, plasma GABA levels are low compared to psychiatrically normal controls. Low plasma GABA in this subgroup of patients has characteristics of a biological trait marker for mood disorders. Low plasma GABA is also found in a subset of patients with alcohol dependence, but not in schizophrenia, anxiety, or eating disorders, suggesting some diagnostic specificity. Previous data from a small study of monozygotic twins are consistent with the hypothesis that plasma GABA levels are under genetic control. To better understand these mechanisms, we conducted a segregation analysis of plasma GABA levels in a sample of 157 individuals from 50 nuclear families. Analysis using the Class D regressive model indicated that the familial transmission of plasma GABA levels is compatible with the segregation of a recessive major gene. Our results suggest that plasma GABA levels are under single gene control. Future research should address the precise mechanisms which may account for the abnormality in GABA levels seen in a subset of patients with mood disorders.

Plasma gamma-aminobutyric acid (GABA) predicts outcome in patients with alcohol dependence

1. Previous studies have suggested that low plasma GABA levels (< or = 100 pmol/ml) may characterize a subset of patients with alcohol dependence. 2. In order to assess the clinical relevance of this biologic finding, the authors followed 49 alcohol dependent patients for up to 18 months following inpatient treatment. Treatment outcome was assessed by continuous abstinence and continued contact with research personnel. 3. Alcohol dependent patients with low plasma GABA had significantly better outcome than patients with plasma GABA in the normal control range (101-150 pmol/ml). 4. These findings suggest that plasma GABA measures may prove to be clinically useful in identifying alcohol dependent patients at risk for relapse.

Isometric torso rotation strength: effect of training frequency on its development

OBJECTIVE

To examine training frequency's effect on torso rotation muscle strength.

DESIGN

The study followed a pretest-posttest randomized-group design.

SETTING

University laboratory.

PATIENTS

Subjects, 33 men (age 30 +/- 11yr) and 25 women (age 28 +/- 10yr) with no history of low back pain, volunteered to participate in the study and were tested for isometric (IM) torso rotation strength before (T1) and after (T2) 12 weeks of training. Measurements of maximal voluntary IM torso rotation torque (N.m) were made through a 108 degrees range of motion (54 degrees, 36 degrees, 18 degrees, 0 degree, -18 degrees, -36 degrees, -54 degrees). Subjects were stratified by peak torque at T1, and randomized to a nonexercising control group (C, n = 10), or groups that trained once a week (1x/wk, n = 16), twice a week (2x/wk, n = 17), or three times a week (3x/wk, n = 15); and all groups were similar in strength.

INTERVENTIONS

Training consisted of 8 to 12 repetitions of full range dynamic variable resistance exercise to volitional fatigue, for both left and right rotation.

MAIN OUTCOME

To determine the best training frequency for the development of torso rotation strength.

RESULTS

Relative improvements (average increase in strength gained at each angle) for the training groups were 4.9%, 16.3%, and 11.9% for the 1, 2, and 3x/wk groups, respectively. The 1x/wk group did not increase in IM torso rotation strength compared to the control group at any angle. Both the 2 and 3x/ wk groups increased their IM torso rotation strength compared to the control group at all but one angle. There were no significant differences in IM torso rotation strength between the groups that trained 2 or 3x/wk. During the training period, the 2 and 3x/wk groups increased their dynamic training load significantly more than the 1x/wk group.

CONCLUSIONS

Posttraining dynamic strength was not different between training frequencies of 2 and 3x/wk. Therefore, training the rotary torso muscles 2x/wk is recommended.

Benzodiazepines as antidepressants: does GABA play a role in depression?

Benzodiazepines, the most widely prescribed psychotropic drugs, are often used in patients with depressive disorders, either alone or in combination with standard antidepressants. This review evaluates the efficacy of benzodiazepines (alprazolam, diazepam, chlordiazepoxide) as established in acute-phase, randomized controlled trials (RCTs) in major depressive disorder. Metaanalyses using intent-to-treat, as well as adequate treatment exposure samples, revealed an overall efficacy of 47-63% and a drug-placebo difference of 0-27% for all benzodiazepines. Alprazolam, the best studied of the benzodiazepines, had a 27.1% (sd = 6.1%) greater response than placebo, which is comparable to standard antidepressants. Alprazolam, in particular, may be a useful treatment option for patients in whom standard antidepressant medications are contraindicated, poorly tolerated, or possibly ineffective. Alprazolam may have a more rapid onset of action for some patients. Benzodiazepines do not primarily affect biogenic amine uptake or metabolism, although they do augment gamma-amino butyric acid (GABA) activity. The antidepressant efficacy of benzodiazepines, which are GABAA receptor agonists, is consistent with the GABA theory of depression.

Stability of plasma GABA at four-year follow-up in patients with primary unipolar depression

The biology of mood disorders involves gamma-aminobutyric acid (GABA), a neurotransmitter whose levels in plasma likely reflect brain GABA activity. Previous research has shown that a subset of patients with primary unipolar major depression have low plasma GABA levels, which parallels findings from studies of cerebrospinal fluid. We have completed a 4-year follow-up on 46 male patients with primary unipolar depression. Plasma levels of GABA were stable over this time. For the group, mean plasma GABA levels on follow-up did not change significantly from entry levels. Plasma GABA levels measured on follow-up were significantly (p < .001) correlated with entry levels. Patients with low plasma GABA levels (< 100 pmol/ml) on entry into the study were likely to remain low on follow-up, and patients with plasma GABA levels in the control range (> or = 100 pmol/ml) at entry similarly remained in this category (chi 2 = 7.23, p = .007). This was true whether or not the patient had recovered from depression on follow-up. Levels of plasma GABA did not significantly correlate with severity of depression at either entry (p = .40) or follow-up (p = .52), nor was there a significant correlation between change in plasma GABA and change in the 17-item Hamilton Depression Rating Scale score from entry to follow-up (p = .89). These data are consistent with the notion that plasma GABA is independent of clinical state in patients with primary unipolar depression. Low plasma GABA may be a trait marker of illness in a subset of patients with mood disorder.

Serotonin and impulsive/aggressive behavior in cocaine dependent subjects

1. 10 male cocaine dependent patients and 10 sex matched controls were administered several behavioral measures of aggression including the Buss-Durkee Hostility Inventory, and The Brown-Goodwin Life History of Aggression. 2. All subjects were also administered a buspirone neuroendocrine challenge as a measure of serotonin function. 3. The cocaine dependent subjects were significantly more aggressive than the controls. 4. There was a significant correlation between the growth hormone response to buspirone and behavioral measures of aggression in the cocaine dependent subjects, but not in the controls. 5. There was no difference in the overall growth hormone response between the controls and cocaine dependent subjects, possibly due to differences in metabolism of buspirone. 6. This study supports a role for serotonin in aggression in cocaine dependent subjects.

A preliminary neuroendocrine study with buspirone in major depression

We administered the serotonin-1a agonist buspirone (0.4 mg/kg orally) as a neuroendocrine challenge agent to a group of male patients with DSM-III-R major depressive disorder (MDD) (n = 13) and a group of male healthy controls (n = 10). The primary hypothesis of the study was that the prolactin response to buspirone would be blunted in the depressed patients. The prolactin response was significantly lower in depressed patients than in controls. There was no significant relationship between placebo corrected-peak prolactin level and severity of depression or suicidality. There was a nonsignificant trend for the melancholic (n = 5) depressed patients to have a lower placebo corrected-peak prolactin level than nonmelancholic depressed patients (n = 8). Our findings support a role for the serotonin-1a receptor in the etiology of MDD, specifically at the postsynaptic site.

The influence of pH and household plumbing on water lead concentration

The water lead concentrations measured in the homes of children who were part of the Edinburgh Lead study are related to the characteristics of the water supply and the household plumbing. At the time of the study one of the City of Edinburgh's two water supplies was lime treated to reduce plumbosolvency but in the second supply this treatment had not yet become effective. This allows us to estimate the extent to which this type of water treatment reduces water lead concentrations, in houses with lead plumbing, to comply with existing and proposed limits for lead in water. The kitchen cold water was supplied from a lead storage tank in 69 (15%) of the houses. These houses had the highest lead concentrations and water tre.

Frequency and volume of resistance training: effect on cervical extension strength

Quantification of cervical extension (CERV EXT) strength is complicated by the inability to stabilize the torso and isolate the CERV EXT muscles. A newly developed machine designed to stabilize the torso and isolate the CERV EXT muscles was used to evaluate the effect of frequency and volume of resistance training on CERV EXT strength. Fifty men (age, 26 +/- 9 years; height, 174 +/- 16 cm; weight, 74 +/- 9 kg) and 28 women (age, 30 +/- 9 years; height, 152 +/- 32 cm; weight, 62 +/- 7 kg) volunteered to participate. Subjects were randomly stratified to one of four training groups or a control group (CONT, n = 19) that did not train. Each training group exercised for 12 weeks as follows; once per week using one set of dynamic exercise (DYN 1x/wk, n = 14), once per week using one set of DYN and one set of maximal isometric (IM) exercise at eight angles through a 126 degrees-range of CERV EXT (DYN-IM 1x/wk, n = 16), DYN 2x/wk (n = 19), or DYN-IM 2x/wk (n = 10). Maximal IM torque was measured at eight angles initially and after 12 weeks of training. All training groups improved CERV EXT strength (p < or = 0.05) at all angles tested compared to the CONT except for DYN once per week at 0 degree of CERV flexion. A greater increase in strength was found when the groups that trained two times a week were compared to those that trained once per week.(ABSTRACT TRUNCATED AT 250 WORDS)

Desipramine does not alter plasma GABA in patients with major depression

Low plasma GABA is a biological marker for depression in a subset of patients tested. Plasma GABA has been shown to reflect brain GABA activity. This marker has many characteristics of a trait marker for depression, including stability with time, and lack of influence by coincident factors such as gender, season, time, activity or diet. We here report that plasma GABA remained stable after 4 weeks of treatment with desipramine in patients with major depression. Since the levels of plasma GABA did not change with time, nor with clinical improvement, plasma GABA is not a state marker of depression.

Low plasma GABA is a trait-like marker for bipolar illness

Plasma gamma-aminobutyric acid (pGABA) is an index of brain GABA activity and a peripheral marker of mood disorder. Previous research has indicated that pGABA is abnormally low in approximately 40% of patients symptomatic with primary unipolar depression. We have now measured pGABA in a series of patients with bipolar disorder. Blood samples for GABA determinations were collected soon after admission to hospital or clinic while patients were symptomatic. In both manic and depressed phase bipolar patients, mean levels of pGABA were significantly lower than in healthy control subjects. The distribution of pGABA in bipolar patients, whether manic or depressed, was similar to that in symptomatic unipolar depression, with 30% to 40% having pGABA levels lower than the control range. These data indicate that low pGABA is not specific to the depressed state, as it is also found in the manic phase of bipolar disorder. Low pGABA may represent a shared biologic correlate between bipolar and unipolar illness.

A comparative study of paranoid and schizoid personality disorders

OBJECTIVE

Family studies have demonstrated a higher rate of schizoid personality in the families of probands with schizophrenia and a higher rate of paranoid personality in the families of probands with delusional disorder. The authors sought to investigate the familial characteristics of probands with schizoid and paranoid personality disorders and to delineate the clinical characteristics of the two groups.

METHOD

Records of 351 inpatients with discharge diagnoses that included the term "schizoid personality" or "paranoid personality" were examined to identify patients who met DSM-III-R criteria for schizoid personality disorder (N = 34) or paranoid personality disorder (N = 19). Comparisons were made between the two groups with respect to clinical symptoms, familial characteristics, and longitudinal course.

RESULTS

The authors found that probands with schizoid personality disorder were hospitalized at an earlier age than probands with paranoid personality disorder, had more intervention before the index admission, and had greater morbidity following the index admission. They also found that descriptors of the two syndromes tended to congregate in the respective family material, but the differences were not statistically significant. Differences in the familial prevalence of schizophrenia were also not statistically significant.

CONCLUSIONS

These familial data do not support the hypothesis that schizophrenia congregates in the families of probands with schizoid personality disorder. Possible explanations for this finding are discussed.

Lumbar strengthening in chronic low back pain patients. Physiologic and psychological benefits

The effects of exercise for isolated lumbar extensor muscles were examined in 54 chronic low-back pain patients. Subjects were randomly assigned to a 10-week exercise program (N = 31) or a wait-list control group (N = 23). Results indicated a significant increase in isometric lumbar extension strength for the treatment group and a significant reduction in reported pain compared with the control group (P 0.05). Treated subjects reported less physical and psychosocial dysfunction whereas the control group increased in pain, and physical and psychosocial dysfunction. There were no concomitant changes in reported daily activity levels. These results show that lumbar extension exercise is beneficial for strengthening the lumbar extensors and results in decreased pain and improved perceptions of physical and psychosocial functioning in chronic back pain patients. However, these improvements were not related to changes in activities or psychological distress.

Chemotherapy and treatment scheduling: the Johns Hopkins Oncology Center Outpatient Department

The Chemotherapy and Treatment Scheduling System provides integrated appointment and facility scheduling for very complex procedures. It is fully integrated with other scheduling systems at The Johns Hopkins Oncology Center and is supported by the Oncology Clinical Information System (OCIS). It provides a combined visual and textual environment for the scheduling of events that have multiple dimensions and dependencies on other scheduled events. It is also fully integrated with other clinical decision support and ancillary systems within OCIS. The system has resulted in better patient flow through the ambulatory care areas of the Center. Implementing the system required changes in behavior among physicians, staff, and patients. This system provides a working example of building a sophisticated rule-based scheduling system using a relatively simple paradigm. It also is an example of what can be achieved when there is total integration between the operational and clinical components of patient care automation.

Primary bony and cartilaginous sarcomas of chest wall: results of therapy

Primary bony and cartilaginous sarcomas of the chest wall are uncommon, and data concerning treatment and results are sparse. To assess the results of therapy, we reviewed our 40-year experience. Records of 38 patients with osteosarcoma and 88 with chondrosarcoma arising in chest wall admitted to Memorial Sloan-Kettering Cancer Center from 1949 to 1989 were reviewed. The 88 patients with chondrosarcoma ranged in age from 5 to 86 years (median age, 49 years); the male/female ratio was 1.3:1. Presenting complaint was mass, pain, or both in 93%. Primary therapy was resection (n = 84), radiation therapy (n = 3), or chemotherapy (n = 1). Overall 5-year survival was 64%. Significant adverse prognostic factors included metastases at initial presentation (n = 9), metastases at any time during the course of disease (n = 23), age greater than 50 years (n = 42), incomplete or no resection (n = 13), and local recurrence (n = 24). Sex, grade, and tumor size were not prognostic factors. The 38 patients with osteosarcoma ranged in age from 11 to 78 years (median age, 42 years); the male/female ratio was 1.5:1. Presenting complaint was mass, pain, or both in 95%. Primary therapy included resection (n = 31; alone in 13, with radiation therapy in 3, with chemotherapy in 15), radiation therapy (n = 3), radiation therapy and chemotherapy (n = 2), chemotherapy (n = 1), or no treatment (n = 1). Overall 5-year survival was 15%. Significant adverse prognostic factors included presence of synchronous metastases (n = 13) and metastases at any time during the course of disease (n = 26).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative assessment and training of isometric cervical extension strength

The purpose of this study was to evaluate the reliability and variability of repeated measurements of isometric cervical extension strength and determine the effect of 10 weeks of dynamic variable resistance cervical extension training on isometric cervical extension strength. Seventy-three subjects (age, 29 +/- 12 years [mean +/- SD]) completed isometric cervical extension strength tests on 4 separate days (D1, D2, D3, and D4). For each test, isometric cervical strength was measured at 126 degrees, 108 degrees, 90 degrees, 72 degrees, 54 degrees, 36 degrees, 18 degrees, and 0 degrees of cervical flexion. Between-day correlation coefficients over the eight angles of cervical flexion were high for D2 versus D3 (r = 0.90 to 0.96). Test variability (standard error of estimate) between D2 versus D3 was low (7.4% to 10.2% of mean) through the entire range of motion. Regression analysis showed that the isometric cervical extension strength curve is linear and descending from flexion to extension. In a second study, 14 subjects (age, 25 +/- 3 years) trained the cervical extensor muscles for 10 weeks while 10 subjects (age, 23 +/- 3 years) served as controls. Training included 8 to 12 cervical extensions to volitional fatigue, 1 day per week. The training group improved isometric cervical extension strength at six of eight angles before to after training (P less than or equal to 0.05). During the same time period the control group did not change. These data indicate that repeated measures of isometric cervical extension strength are highly reliable and can be used for the quantification of isometric cervical extension strength through a 126 degrees range of motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of hysterectomy on bowel and bladder function

A case control study compared the bowel habit of 91 post-hysterectomy women with paired controls from the same family doctor practice. More cases had an abnormal bowel frequency, a firmer stool consistency and assessed themselves as having abnormal bowel function, predominantly constipation after hysterectomy, than controls. Significantly more cases than controls had consulted a doctor because of constipation but there was no significant difference in laxative usage. There was a significant short-term association between decreased bowel frequency and increased urinary frequency after hysterectomy. This became highly significant in those patients who developed chronic symptoms. Oophorectomy, unilateral or bilateral, did not significantly affect bowel habit other than to intensify the change in stool consistency. The hypothesis is discussed that the post-hysterectomy effects on bowel and bladder function may have a common aetiology in a degree of autonomic denervation of both viscera.

Quantitative assessment of full range-of-motion isometric lumbar extension strength

The purpose of this study was to evaluate the reliability and variability of repeated measurements of isometric (IM) lumbar extension (LB EXT) strength made at different joint angles. Fifty-six men (age, 29.4 +/- 10.7 years) and 80 women (age, 24.3 +/- 9.1 years) completed IM LB EXT strength tests on 3 separate days (D1, D2, and D3). On D1 and D2, subjects completed two tests (T1 and T2) separated by a 20- to 30-minute rest interval. For each test, IM LB EXT strength was measured at 72, 60, 48, 36, 24, 12, and 0 degrees of lumbar extension. Mean IM strength values, within-day reliability coefficients, and test variability over the seven angles improved from D1 to D2 (D1: mean, 160.0 to 304.1 N.m, r = 0.78 to 0.96, SEE = 37.6 to 46.9 N.m; D2: mean, 176.3 to 329.1 N.m, r = 0.94 to 0.98, SEE = 29.0 to 34.4 N.m). Mean strength values leveled off by D3 (174.5 to 317.0 N.m). The most reliable test results showed that the IM LB EXT strength curves were linear and descending from flexion to extension and ranged from 235.8 +/- 85.2 to 464.9 +/- 150.7 N.m for men (extension to flexion) and from 134.6 +/- 53.2 to 237.3 +/- 71.9 N.m for women. Lumbar extension strength was clearly greatest in full flexion, which is in contrast to previously reported results. One practice test was required to attain the most accurate and reliable results. These data indicate that repeated measures of IM LB EXT strength are highly reliable and can be used for the quantification of IM LB EXT strength through a range of motion.

Linoleic acid and coronary heart disease

Low tissue concentrations of the essential fatty acid, linoleic acid, occur in communities with high rates of coronary disease and in patients with angina and myocardial infarction. This relationship is independent of lipids and blood pressure, but in smokers linoleic acid is particularly low because they eat less linoleic acid-containing foods.

Effect of resistance training on lumbar extension strength

Development of a new testing machine, which stabilizes the pelvis, allowed us to evaluate the lumbar extensor muscles before and after training. Fifteen healthy subjects (29.1 +/- 8 years of age) trained 1 day per week for 10 weeks and 10 healthy subjects (33.7 +/- 16 years of age) acted as controls. Training consisted of 6 to 15 repetitions of full range of motion variable resistance lumbar extension exercise to volitional fatigue and periodic maximal isometric contractions taken at seven angles through a full range of motion. Before and after the 10 week training period, subjects completed a maximum isometric strength test at seven angles through a 72 degrees range of motion (0 degrees, 12 degrees, 24 degrees, 36 degrees, 48 degrees, 60 degrees, and 72 degrees of lumbar flexion). The training group significantly improved in lumbar extension strength at all angles (P less than or equal to 0.01). The result at 0 degrees (full extension) showed an increase from 180.0 +/- 25 Nm to 364.1 +/- 43 Nm (+102%) and at 72 degrees (full flexion) from 427.4 +/- 44.1 to 607.4 +/- 68 (+42%) Nm. Results from the control group showed no change (P greater than or equal to 0.05). The magnitude of gain shown by the training group reflects the low initial trained state of the lumbar extensor muscles. These data indicate that when the lumbar area is isolated through pelvic stabilization, the isolated lumbar extensor muscles show an abnormally large potential for strength increase.

Blood-lead levels and children's behaviour--results from the Edinburgh Lead Study

The effect of blood-lead on children's behaviour was investigated in a sub-sample of 501 boys and girls aged 6-9 years from 18 primary schools within a defined area of central Edinburgh. Behaviour ratings of the children were made by teachers and parents using the Rutter behaviour scales. An extensive home interview with a parent was also carried out. Multiple regression analyses showed a significant relationship between log blood-lead and teachers' ratings on the total Rutter score and the aggressive/anti-social and hyperactive sub-scores, but not the neurotic sub-score when 30 possible confounding variables were taken into account. There was a dose-response relationship between blood-lead and behaviour ratings, with no evidence of a threshold.

Cigarette smoking, social class and nutrient intake: relevance to coronary heart disease

The association of cigarette smoking habits and social class with nutrient intake was investigated in 162 men aged 45-54 using a 7-d weighed dietary record. Cigarette smokers had a significantly lower intake of fibre and polyunsaturated fatty acids and a lower P:S ratio than non-smokers. Fibre intake was lower in men in the manual compared to the non-manual group but smoking was a more powerful influence than social class. The differences in nutrient intake were accompanied by differences in the consumption of polyunsaturated margarines and cereal-containing foods. These results should be considered in the explanation of the increased incidence of coronary heart disease in smokers.

The variability of lead in dusts within the homes of young children

The variability of household dust lead concentration and loadings over the period of about a year has been examined in 10 homes. The overall uncertainty on a single sample is ± 65% for lead concentration and ± 81% for lead loading. Redecoration involving electric sanding and/or blow lamp preparation of painted surfaces is the major cause of variation in lead levels. The effect is short lived, levels returning to normal within 2 months of redecoration ending. There is evidence of a seasonal trend for dust loading and lead loading but not for lead concentration. The implications of these findings for blood lead - dust lead exposure studies are considered.

Alcohol consumption and nutrient intake in middle-aged Scottish men

The relation between alcohol consumption and dietary intake was examined in 164 middle-aged Scottish men taking part in a study of risk factors for coronary heart disease (CHD). A 7-d weighed dietary record was used to assess alcohol and nutrient intake. The mean daily intake of alcohol was 26 g (SD 31 g). Energy derived from alcohol tended to replace energy derived from other nutrients and increasing intake of alcohol was associated with a decrease in the amounts of carbohydrate, total fat, and saturated and monounsaturated fatty acids in the diet. Those with a low alcohol intake (0.1-9 g alcohol/d) had a higher intake of total fiber, cereal fiber, polyunsaturated fatty acids, and linoleic acid and a smaller proportion smoked cigarettes. The differences are small but may contribute to the lower mortality from CHD reported by other studies in those with a low alcohol intake.

Lead from dust and water as exposure sources for children

Data from the Edinburgh Lead Study are used to estimate the respective contributions of water and dust lead to blood lead in 6-9 year old children. Both sources are significantly related to blood lead. An exposure of 100 μg/l in kitchen cold water is estimated to be equivalent to 2700 μg/g of lead in dust. In this population water is a more important source of lead than dust for the bulk of the population.

Influence of blood lead on the ability and attainment of children in Edinburgh

The effect of blood-lead on children's ability and attainment was investigated in a sample of 855 boys and girls aged 6-9 years from eighteen primary schools within a defined area of central Edinburgh. The geometric mean blood-lead value was 10.4 micrograms/dl. In a stratified subsample, 501 children completed individual tests of cognitive ability and educational attainment from the British Ability Scales (BAS). An extensive home interview with a parent was also done. Multiple regression analyses showed a significant negative relation between log blood-lead and BAS combined score, number skills, and word reading when thirty-three possible confounding variables were taken into account. There was a dose-response relation between blood-lead and test scores, with no evidence of a threshold. The size of the effect was small compared with that of other factors. Lead at low levels of exposure probably has a small harmful effect on the performance of children in ability and attainment tests.

A comparison of the nutrient intake of some Scotsmen with dietary recommendations

During 1980 and 1982, 164 men aged 45-54 in North Edinburgh and West Fife participated in a 7-day individual weighed dietary survey. The mean energy intake was 11.2 MJ (2700 kcal), 38.1 per cent of which came from fat and 6.7 per cent from alcohol. The P:S ratio was 0.30 and the mean daily fibre intake 19.8 g. Saturated fatty acids accounted for 16.3 per cent of the energy and polyunsaturated fatty acid for 4.6 per cent. Oleic acid was the principal dietary fatty acid accounting for 32.4 per cent of fatty acids. The major polyunsaturated fatty acid was linoleic acid and contributed 3.5 per cent of energy. Cereal and cereal products were the principal source (30.8 per cent) of linoleic acid. Though this study was conducted prior to the publication of recent dietary recommendations, a small proportion of the men were achieving some of them but few would have met the recommendations in full.

Cross-sectional thigh components: computerized tomographic assessment

The purpose of this study was to examine the efficacy of the Picker Synerview Fourth Generation CT Scanner in assessing cross-sectional areas of muscle, bone, and subcutaneous fat of the thigh. A secondary purpose was to resolve individual muscle bellies using the CT scanner and to determine the effects of body composition in isolating those muscles. Both limbs of one cadaver were used to compare actual cross-sectional areas with the CT images. Each limb was dissected and photographed. Accuracy of repeated measurements was assessed using human volunteers. Absolute and percent error between the CT measurements and the measurements of the cross-sectional areas differed most at the bone. No differences were found between repeat scans. CT images and photographic measurements of individual muscles were generally quite similar, as assessed by absolute and percent error. The gracilis and sartorious were reasonably well defined in those individuals with more than 8% body fat. The results are discussed in terms of possible applications of the CT scanner in sports medicine research.