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Biomedical subjects

M Davis

Publications and source records attributed to M Davis.

At least 523 records · Page 29Linked to original sources
PubMed1984

Salary survey of the Medical Library Group of Southern California and Arizona.

The 1982 salary survey of the Medical Library Group of Southern California and Arizona (MLGSCA) indicates that 211 health sciences librarians in Southern California and Arizona earned a mean annual salary of $20,910 for 1982. Data analysis shows a positive correlation between salary and educational level. Other factors found to affect salary were job history, number of positions held, MLA certification, and professional responsibility. Age, gender, and MLA certification did not have a consistent positive correlation with salary. Results indicate that the salaries of hospital librarians are, on the average, roughly comparable to those of academic librarians in Southern California and Arizona.

Age Factors↗
PubMed1983

Severity of alcohol dependence in patients with alcoholic liver disease.

To determine the severity of dependence on alcohol in patients with alcoholic liver disease the severity of alcohol dependence questionnaire was administered to 193 patients with various types of alcoholic liver disease established histologically, in whom a detailed history of lifetime alcohol consumption was also obtained. Only 34 patients (18%) were classified as being severely dependent compared with 56% of patients without overt liver disease who were attending a neighbouring alcohol treatment unit. There was a significant correlation between the severity of dependence and mean daily alcohol consumption (r = 0.45 and 0.39 for men and women, respectively) but not duration of drinking. Dependence scores tended to be lower in patients with cirrhosis than in those with precirrhotic liver disease, but this difference reached significance only in women. These findings confirm that patients who develop chronic alcoholic liver disease are usually only mildly dependent on alcohol and support the hypothesis that patients who escape florid symptoms of alcohol dependence are at greater risk of developing liver damage because they are able to sustain a continual consumption of alcohol over many years.

Adult↗
PubMed1983

Spinal clonidine inhibits neural firing in locus coeruleus.

Intrathecally-administered clonidine inhibited the spontaneous firing of single neurons in the pontine nucleus locus coeruleus of rats. Such inhibition of neuron firing was not observed when the non-lipophilic alpha 2 adrenoceptor agonist (oxymetazoline) was administered intrathecally. It is concluded that lipophilic drugs like clonidine, when administered intrathecally, can have profound supraspinal actions and thus caution should be exercised in interpreting the sites of action of such drugs.

Animals↗
PubMed1983

Estimation of urinary nitrogen losses from urea excretion in patients with intestinal diseases requiring parenteral nutrition, and in those with hepatic decompensation.

A comparison of daily urinary nitrogen excretion measured directly, with values derived from urea excretion, was carried out on 110 occasions in patients with either gastrointestinal disease requiring total parenteral nutrition or with alcoholic liver disease. The values were found to correlate well in both patient groups (r = 0.88 and 0.9 respectively). Values of urinary nitrogen loss calculated from urea excretion may safely be used when performing nitrogen balance studies in such cases.

Dietary Proteins↗
PubMed1983

A visual pathway that mediates fear-conditioned enhancement of acoustic startle.

Eighty rats received 10 light-shock pairings on two successive days. Seventy-two h after the final training session, subjects received lesions directed at the primary visual areas (deep and superficial layers of the superior colliculus, dorsal lateral geniculate nucleus, pretectal nuclei, visual cortex and thalamic reticular nucleus) and at the nuclei of the lateral lemniscus and reticularis pontis caudalis, proposed components of a primary acoustic startle circuit in the rat. Control animals were sham operated. One day later, all animals were tested for startle by presenting noise bursts of 3 different intensities in the presence or absence of the light conditioned stimulus. Potentiated startle (the difference between light-noise vs noise-alone trials) was significantly attenuated or eliminated by lesions directed at the dorsal nucleus of the lateral geniculate, deep layers of the superior colliculus, visual cortex, and the posteroventral region of the nucleus of the lateral lemniscus. Lesions directed at pretectal nuclei, superficial layers of the superior colliculus, thalamic reticular nucleus, nucleus reticularis pontis caudalis or dorsal nucleus of the lateral lemniscus did not attenuate potentiated startle. The results suggest that the visual pathway that mediates potentiated startle goes from the retina to the dorsal lateral geniculate nucleus to visual cortex to deep layers of superior colliculus and down to the postero-ventral region of the lateral lemniscus where acoustic startle is modulated.

Acoustic Stimulation↗
PubMed1983

Functional supersensitivity of CNS alpha 1-adrenoceptors following chronic antidepressant treatment.

Chronic but not acute administration (21 days) of desipramine (10 mg/kg), amitriptyline (10 mg/kg) or iprindole (5 mg/kg) enhanced the stimulatory effect of the alpha 1-adrenergic agonist phenylephrine on the acoustic startle reflex when phenylephrine was infused into the subarachnoid space of the spinal cord. Comparable supersensitivity to phenylephrine also occurred 1 week after selective depletion of norepinephrine in the spinal cord via intrathecal administration of 6-hydroxydopamine. Behavioral supersensitivity to phenylephrine was associated with an increase in the number of 3H-prazosin binding sites following denervation but not following chronic antidepressant treatments. The results indicate that chronic antidepressant treatments may enhance functional alpha 1-adrenergic transmission through mechanisms different than those following denervation.

Amitriptyline↗
PubMed1983

Importance of markers of hepatitis B virus in alcoholic liver disease.

To determine the importance of the presence of serological markers of hepatitis B virus infection in patients with alcohol related liver disease we compared cumulative alcohol intake and clinical and histological features in patients with markers of hepatitis B virus infection and in those without. Hepatitis B surface antigen (HBsAg) was detected in five (2%) out of 285 patients studied and antibody to HBsAg (anti-HBs) in 41 (14%); one patient had antibody to hepatitis B core antigen alone. The combined prevalence of markers of hepatitis B virus infection was similar in patients with alcoholic cirrhosis (18%) and precirrhotic liver disease (13%). Two patients positive for HBsAg had histological features of both alcoholic liver disease and chronic active hepatitis, with stainable HBsAg. Patients with anti-HBs were, however, histologically indistinguishable from patients without markers, and the mean cumulative alcohol intake of patients with anti-HBs was similar to or even higher than that of patients with liver disease of comparable severity who had no evidence of previous infection. The presence of markers of hepatitis B virus infection was related to former residence in countries with a high prevalence of the infection and to previous parenteral treatment and blood transfusions. Infection with hepatitis B virus does not enhance the development of chronic liver disease in heavy drinkers, except in the small number who remain positive for HBsAg.

Adult↗
PubMed1983

Behavior and binding: correlations between alpha 1-adrenergic stimulation of acoustic startle and alpha 1-adrenoceptor occupancy and number in rat lumbar spinal cord.

The relationship between alterations in alpha 1-adrenoceptors and behavioral effects of alpha 1-adrenergic agonists were investigated in a localized region of the rat central nervous system. Direct infusion of the alpha 1-adrenergic agonists, D-amphetamine or phenylephrine. into the subarachnoid space of the lumbar cord (intrathecal administration) increased the amplitude of the acoustic startle reflex, The magnitude of this behavioral facilitation correlated highly with the degree of alpha 1-adrenoceptor occupation measured by [3H]prazosin binding in lumbar spinal tissue. Using an in vitro estimate of receptor occupation, maximal potentiation of startle occurred following approximately 30% occupation of the receptors, using either D-amphetamine or phenylephrine. Intrathecal administration of 6-OHDA produced a 95% decrease in spinal norepinephrine and markedly enhanced the behavioral response to intrathecal phenylephrine as well as the number of alpha 1-adrenoceptors. The correlation between the time course of the behavioral and binding changes was 0.99. No change in receptor affinity (KD) or receptor occupation by phenylephrine was found after 6-OHDA. The data indicate that receptor binding parameters do have predictive value for behavior, especially if localized regions of the nervous system, critical to the behavior, are analyzed.

Acoustic Stimulation↗
PubMed1983

Localisation of the human N-ras oncogene to chromosome 1cen - p21 by in situ hybridisation.

The N-ras gene is a transforming gene isolated from a variety of human tumour cell lines and is a member of a family of related ras genes. Somatic cell hybrids have previously shown that the N-ras gene is located on chromosome 1. We have confirmed this localisation by in situ hybridisation to metaphase preparations of lymphocytes and localised the gene to the region 1cen - p21. A survey has found 47 reported cases of malignancy involving deletions in the short arm of chromosome 1. Fifteen of the 47 involved a deletion in this region.

Chromosome Mapping↗
PubMed1983

Development changes in pharmacological responsivity of the acoustic startle reflex: effects of picrotoxin.

Using the acoustic startle reflex as the behavioral measure, qualitatively different responses to the GABA antagonist picrotoxin were obtained in developing rats before and after 21 days postnatal (PN) age. Dose-dependent increases in acoustic startle were seen following picrotoxin in PN day 15-16 rat pups. In contrast, dose-dependent decreases in startle following picrotoxin were observed in adult rats. The switch from excitation to inhibition of startle was found to occur abruptly on PN day 21. Excitatory responses to picrotoxin were also found in adult rats following localized infusions of picrotoxin into lumbar spinal cord regions, but not into the forebrain. These results give evidence that picrotoxin-sensitive sites that modulate increases in startle reflex behavior mature first and are analogous to sites in the adult spinal cord, whereas picrotoxin-sensitive sites that modulate decreases in startle reflex behavior mature later (greater than or equal to PN day 21) and are localized in more rostral brain areas.

Acoustic Stimulation↗
PubMed1983

Excitatory effects of the vasodilator hydralazine on acoustic startle in the rat.

Several drugs that functionally depress noradrenergic transmission depress acoustic startle amplitude (e.g., clonidine, phenoxybenzamine). Since these agents also depress blood pressure, the current study was designed to investigate the effects of hypotension per se (in the absence of decreased noradrenergic transmission) on the acoustic startle response. The vasodilator hydralazine was chosen because it produces marked hypotension in conscious rats, yet results in a compensatory increase in noradrenergic transmission (sympathetic rebound), rather than a decrease, as is seen with many other hypotensive agents. Hydralazine (0.3-20 mg/kg, IP) produced a marked and long-lasting increase in startle amplitude, compared to saline-treated controls. In a similar group of subjects, IP administration of 2.5 mg/kg hydralazine decreased mean arterial blood pressure by about 50% in conscious rats. Since, at the doses and treatment times employed in the present study, hydralazine decreases blood pressure but not startle amplitude, these data suggest that there is no relationship between changes in blood pressure and changes in startle amplitude across all drugs. Moreover, since hydralazine-induced hypotension results in an increase in noradrenergic transmission (sympathetic rebound), these data are consistent with the hypothesis that increases in central noradrenergic transmission increase acoustic startle amplitude. Lastly, since the most prominent direct action of hydralazine occurs in the periphery, hydralazine may alter startle through central actions that are triggered in the periphery.

Acoustic Stimulation↗
PubMed1983

Treatment of lobar pneumonia in Papua New Guinea: short course chemotherapy with penicillin or chloramphenicol.

In an attempt to reduce the costs of treatment we treated 203 patients with clinical lobar pneumonia either with penicillin or chloramphenicol for periods of up to 24 hours after remission of fever (mean 2.4 days). The results show that for patients with moderately severe pneumonia short-course treatment is as effective as the more traditional treatment. Patients with severe pneumonia may respond to such treatment but require careful evaluation before stopping treatment.

Adult↗
PubMed1983

Specific serological markers in the diagnosis of fulminant hepatic failure associated with halothane anaesthesia.

The aetiology of massive liver-cell necrosis which developed in 16 patients following halothane anaesthesia was investigated by means of new serological techniques. In eight patients a specific halothane-related antibody was found, indicating that these patients were sensitized to halothane-altered liver-cell membrane components. In four patients, hepatitis A viral infection was responsible and among the remainder one was receiving anti-tuberculous drugs and one had received a blood transfusion, thus raising the possibility of a non-A non-B viral infection. There were no biochemical or histological differences between patients in the three groups.

Acute Disease↗
PubMed1983

Sleep disturbances in the institutionalized aged.

One hundred eighty nursing home residents, not psychotic or demented, average age 82 years, were administered a 30-minute structured interview to identify and characterize their sleeping patterns, health status, medications, psychosocial environment, and living conditions. In addition, both the residents and the night nurses rated quality of sleep on a five-point scale. Residents and nurses on all shifts also rated appetite and exercise on five-point scales. Residents were classified as having a sleep disturbance if they met at least one of the following criteria and reported poor sleep quality: onset of sleep latency greater than 30 minutes, three or more nighttime awakenings, and less than six hours sleep per night. Forty-five per cent of the residents met at least one clinical research criterion. Residents with sleep disturbance rated their sleep quality significantly lower than their peers not meeting research criteria. However, the nurses' ratings did not discriminate problem sleepers, and they correlated poorly with the residents' ratings. These subjective patient evaluations are discussed in relation to nursing evaluations, prescription of hypnotic medications, and other variables.

Aged↗
PubMed1983

Lymphocyte cytotoxicity to autologous hepatocytes in alcoholic liver disease.

Cytotoxicity of peripheral blood lymphocytes for autologous hepatocytes has been studied in 18 patients with different histological types of alcoholic liver disease. Cytotoxicity was significantly increased in five of ten patients with cirrhosis and/or alcoholic hepatitis but in only one of eight with fatty infiltration or minor histological changes. The cytotoxic effect of T-and non-T-effector cells was separately evaluated in 11 cases. Of six patients with alcoholic hepatitis, non-T lymphocyte cytotoxicity was increased in five and T-cell in only one. These preliminary results are consistent with the concept that autoimmune reactions may play a role in the development and progression of alcoholic hepatitis and cirrhosis, although it is likely that direct hepatotoxic effects of ethanol or its metabolites are also important in determining the pattern of liver injury and perhaps in initiating the immune reactions observed in this study.

Autoantibodies↗
PubMed1983

Plasma cortisol secretion and REM period latency in adult endogenous depression.

The authors studied the relationship of plasma cortisol secretion and REM period latency in 25 patients with endogenous depression. The 8 patients (32%) with cortisol hypersecretion had a significantly shortened REM period latency in comparison with the 17 with normal cortisol secretion. Furthermore, an extremely short REM latency (20 minutes or less) occurred almost exclusively in those with cortisol hypersecretion. The authors discuss possible neurotransmitter disturbances responsible for these abnormalities and the clinical implications of these findings.

Adult↗