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Biomedical subjects

M H Miller

Publications and source records attributed to M H Miller.

At least 109 records · Page 6Linked to original sources

Measurements of spinal mobility in the sagittal plane: new skin contraction technique compared with established methods.

A new skin contraction (10 cm segment) method for measuring segmental and "total" spinal movement in the sagittal plane is described and compared with the modified Schober test, finger-floor distance and goniometry. Three consecutive 10 cm segments are marked out along the spine from the lumbosacral junction with the patient in full flexion. The amount of contraction occurring within each segment is measured after maximal spinal extension. Skin contraction correlated significantly with comparable measurements by other methods. Interobserver variation was not significant. Mean patient measurement time (+/- SD) was 124 +/- 59 seconds. The 10 cm segment method was found to be more sensitive than other available clinical techniques for detecting loss of spinal mobility in ankylosing spondylitis.

Humans↗

The liver in systemic lupus erythematosus.

A 12-month prospective study was undertaken to determine prevalence and causes of clinical and subclinical liver disease in 260 SLE patients and 100 controls, and to look for concordance between 'unexplained' enzyme elevations and SLE activity. Hepatic status was assessed clinically and by tests of liver function with additional tests where indicated. In 76 per cent of patients there were no clinical or laboratory abnormalities. Liver enzyme elevations occurred in 23 per cent. In 15 per cent there were identifiable causes, and in 8 per cent the elevations were 'unexplained', compared with none in the controls. Four patients had persistent 'unexplained' mild transaminase elevations. Liver tissue available from 14 patients revealed no serious lesions. Data on 156 patients with more than four assessments were analysed. In 12 of 15 patients with 'unexplained' transaminase elevations, changes in SGPT levels were concordant with SLE activity. This study suggests that subclinical liver disease is a manifestation of SLE.

Adolescent↗

Ocular toxicity of high-dose intravenous desferrioxamine.

Desferrioxamine was given intravenously, at higher doses than previously reported, to counter the effects of transfusion-induced iron overload in four patients with beta thalassaemia major. In two of them retinal abnormalities developed, presenting with night blindness and field defects, which improved on withdrawal of the drug.

Adolescent↗

The significance of thrombocytopenia in systemic lupus erythematosus.

The significance of thrombocytopenia in systemic lupus erythematosus (SLE) is unclear. Some researchers have found it associated with severe disease, others with mild disease. Thrombocytopenia (platelets less than 100,000) occurred in 21 patients seen at an SLE clinic over 18 months. Prospective assessment of 19 (non-SLE causes excluded) revealed 2 distinct subgroups. Seven were thrombocytopenic only during severe multisystem flares. Twelve had chronic thrombocytopenia with intermittent mild flares in other systems. Serious bleeding was rare in both subgroups. It was concluded that thrombocytopenia clearly is not a prognostic indicator.

Acute Disease↗

Systemic lupus erythematosus in males.

A study of 51 males being followed in the Wellesley Hospital Toronto SLE Clinic examined the questions of whether SLE in males was similar to that in females and whether affected males differ from unaffected males with respect to their maleness and sex hormone profile. Fifty of the men were phenotypically males, and one was known to have Klinefelter syndrome (karyotype 47 XXY). All had four or more 1982 revised criteria for SLE. Fifty females matched with respect to age and duration of disease were used as controls. In examining the spectrum of the disease, 21 clinical and laboratory manifestations were assessed. Although neurologic involvement, alopecia, and thrombocytopenia were less common and pleuritis more common in the males, none of these was statistically significant. Comparison of disease severity revealed only one statistically significant difference: the mean duration of corticosteroid usage was longer in the females. There was also a tendency for cytotoxic agents to be used more frequently in the females. It was thus concluded that spectrum and severity of the disease tended to be similar in males and females. The frequency of positive family histories for SLE and other autoimmune diseases was similar in males and females. The age of onset tended to be more evenly distributed in males than in females, with one quarter of the males diagnosed after the age of 50. HLA typing revealed increased frequencies of the B8 and DR3 antigens in the SLE males compared with normal controls, as had previously also been shown for SLE populations with a female preponderance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

The acoustic reflex threshold in aging ears.

This study investigates the controversy regarding the influence of age on the acoustic reflex threshold for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators between Jerger et al. [Mono. Contemp. Audiol. 1 (1978)] and Jerger [J. Acoust. Soc. Am. 66 (1979)] on the one hand and Silman [J. Acoust. Soc. Am. 66 (1979)] and others on the other. The acoustic reflex thresholds for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators were evaluated under two measurement conditions. Seventy-two normal-hearing ears were drawn from 72 subjects ranging in age from 20-69 years. The results revealed that age was correlated with the acoustic reflex threshold for BBN activator but not for any of the tonal activators; the correlation was stronger under the 1-dB than under the 5-dB measurement condition. Also, the mean acoustic reflex thresholds for broadband noise activator were essentially similar to those reported by Jerger et al. (1978) but differed from those obtained in this study under the 1-dB measurement condition.

Acoustic Stimulation↗

Membrane potential in anaerobically growing Staphylococcus aureus and its relationship to gentamicin uptake.

The electrical potential (delta psi) across the cytoplasmic membranes of Staphylococcus aureus cells growing under aerobic and anaerobic conditions was determined by measuring the equilibrium distribution of [3H]tetraphenyl phosphonium. In conjunction, gentamicin uptake and killing were studied in the same cells under identical conditions. Under aerobic conditions, delta psi was -169 mV, gentamicin uptake was readily demonstrable, and the number of viable cells decreased by almost four orders of magnitude in the presence of antibiotic. In contrast, delta psi was -142 mV anaerobically, gentamicin uptake was essentially nonexistent, and the aminoglycoside had no effect on viability. Remarkably, when the ionophore nigericin was added under anaerobic conditions, delta psi increased to the level observed aerobically, gentamicin uptake tripled to about 18% of the aerobic level, and viability decreased by one order of magnitude. The results are consistent with other observations (Mates et al., Proc. Natl. Acad. Sci. U.S.A. 79:6693-6697, 1982), indicating that the relationship between delta psi and gentamicin uptake is gated, and suggest that diminution of delta psi may be an important factor in aminoglycoside resistance under anaerobic conditions.

Anaerobiosis↗

Effect of N, N'-dicyclohexylcarbodiimide and nigericin on Staphylococcus aureus susceptibility to gentamicin.

The abilities of the H+-ATPase inhibitor N, N'-dicyclohexylcarbodiimide and the antibiotic ionophore nigericin to enhance the bactericidal effect of subinhibitory concentrations of gentamicin in two strains of Staphylococcus aureus were studied. Each compound significantly increased both gentamicin uptake and killing. The use of agents which alter the plasma membrane energy state is a novel approach to enhance the activity of conventional antibiotics.

Anti-Bacterial Agents↗

Sinusitis: induced subdural empyema.

In 17 cases of sinusitis-induced subdural empyema, all but 5 occurred in boys or men aged 13 to 33 years. Clinical features were headaches and fever (14 patients), nuchal rigidity (10), and seizures (8). Seven patients had periorbital cellulitis, and 15 had radiographic clouding of at least one sinus. Only five patients had a history of sinusitis. CT identified the empyema accurately in seven patients but failed in two patients who developed subdural empyema while being treated for sinusitis-induced cerebritis. Ten patients had specific bacteriologic etiologies determined by culture of empyema, blood, or sinuses.

Adolescent↗

Percutaneous catheter drainage in intraabdominal fluid collections including infected biliary ducts and gallbladders.

Sixty-five abscesses, including 6 infected biliary systems and 15 sterile fluid collections, were treated by percutaneous catheter drainage in 77 febrile patients who were evaluated by computerized tomography or ultrasonography of intraabdominal infection. Percutaneous catheter drainage and systemic antibiotic administration without surgery provided satisfactory control of infection in 52 of 65 abscesses (80 percent). Catheter drainage followed by surgical exploration for abscess control was performed in an additional 5 of 65 abscesses (7 percent). Nine death (14 percent) occurred in the abscess group of 64 patients. In 15 patients, aspirations, Gram stain, and culture of the abnormal fluid collection revealed sterile fluid. Drainage with a single catheter allowed complete resolution in 14 of 15 sterile collections. Surgery was performed electively in one patient with a fistula from a pancreatic pseudocyst in the small bowel. No deaths occurred in the noninfected group of 15 patients, 2 of whom underwent drainage of coexisting abscesses.

Abdomen↗

Membrane potential and gentamicin uptake in Staphylococcus aureus.

At pH 5.0, the electrical potential (delta psi, interior negative) across the plasma membrane of Staphylococcus aureus exhibits a minimum of -85 to -90 mV; the pH gradient (delta pH, interior alkaline) across the membrane approximates a maximum of about -100 mV. Under these conditions, uptake of the aminoglycoside gentamicin is negligible, and viability of the organism is not impaired by the antibiotic. In contrast, at pH 7.5, at which delta psi is about -130 mV and delta pH is 0, gentamicin uptake is observed and the drug markedly decreases viability. Dramatically, when the ionophore nigericin is added at pH 5.0, gentamicin uptake is induced, there is a striking decrease in viability, and the effect is associated with an increase in delta psi at the expense of delta pH. Consistently, valinomycin, which dissipates delta psi in the presence of potassium, abolishes gentamicin uptake and killing. In addition, from pH 5.0 to pH 7.5, there is a direct relationship between the magnitude of delta psi and both gentamicin uptake and its bactericidal effect. However, a threshold delta psi of -75 to -90 mV is apparently necessary to initiate uptake and killing. These observations provide a strong indication that delta psi plays a critical role in the uptake and antibacterial action of gentamicin and suggest that nigericin-like ionophores may be clinically useful in synergy with aminoglycosides.

Biological Transport, Active↗

Double-blind randomised controlled trial of folate treatment before conception to prevent recurrence of neural-tube defects.

A randomized controlled double-blind trial was undertaken in south Wales to prevent the recurrence of neural-tube defects in women who had had one child with a neural-tube defect. Sixty women were allocated before conception to take 4 mg of folic acid a day before and during early pregnancy and 44 complied with these instructions. Fifty-one women were allocated to placebo treatment. There were no recurrences among the compliant mothers but two among the non-compliers and four among the women in the placebo group. Thus there were no recurrences among those who received supplementation and six among those who did not; this difference is significant (p = 0.04). It is concluded that folic acid supplementation might be a cheap, safe, and effective method of primary prevention of neural-tube defects but that this must be confirmed in a large, multicentre trial.

Clinical Trials as Topic↗

Regulation of glucose utilization in chick embryo fibroblasts by bicarbonate ion.

The amount of glucose consumed by chick embryo fibroblasts in primary culture is strongly influenced by the presence of bicarbonate ion in the culture medium. Cells grown on glucose at physiologic concentration (5.5 mm) and in the absence of bicarbonate ion have a reduced rate of glucose utilization when compared to their counterparts cultivated in medium containing the usual 25 mM bicarbonate. The presence or absence of bicarbonate is without effect on chick embryo fibroblast proliferation over a 6-day growth period. Both lactic acid accumulation per mole of glucose consumed and the utilization of glutamine increase as a function of bicarbonate ion in the growth medium.

Animals↗

Acoustic neurinoma in a population of noise exposed workers.

Regulations from the Occupational Safety and Health Administration require the performance of audiometric tests on workers exposed to potentially hazardous noise levels. These tests are frequently performed by Occupational Hearing Conservationists who have taken a 20-hour course based on recommendations of the Council for Accreditation in Occupational Hearing Conservation. Unless audiograms performed by such personnel are promptly reviewed and appropriate referral to specialists made, significant and potentially life-threatening otic disease may go undetected. This paper reports a series of workers with acoustic tumors initially detected by an Occupational Hearing Conservation Program. It is dangerous to assume that the hearing loss and tinnitus reported by noise-exposed workers is necessarily the result of workplace noise exposure.

Adult↗