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Biomedical subjects

D Miller

Publications and source records attributed to D Miller.

At least 469 records · Page 26Linked to original sources
PubMed1988

Interaction of permanently uncharged dopamine analogs with the D-2 dopaminergic receptor.

The purpose of this study was to determine if structural analogs of dopamine in which the side chain nitrogen has been replaced by a permanently uncharged monomethylsulfide, monomethylselenide or sulfoxide group are capable of binding to the striatal D-2 dopamine receptor and acting as agonists at this receptor. All the permanently uncharged dopamine analogs were found to bind to the D-2 dopamine receptor as evidenced by their abilities to inhibit significantly [3H]spiperone binding to striatal homogenates. However, the inhibition of [3H]spiperone binding by the uncharged dopamine analogs was incomplete and was almost abolished by the addition of NaCl (125 mM) to the incubation medium or by the addition of dopamine or quinpirole at a concentration that that saturates the high-affinity state of the D-2 dopamine receptor. These effects of NaCl, dopamine and quinpirole suggest that the uncharged dopamine analogs bind primarily to the high-affinity state of the D-2 dopamine receptor. Whether the uncharged monomethylsulfide and sulfoxide analogs could function as dopamine agonists at the striatal D-2 dopamine receptor was assessed by determining the abilities of these compounds to inhibit the K+-evoked release of [3H]acetylcholine from striatal slices. Both the monomethylsulfide and sulfoxide analogs inhibited the K+-evoked release of [3H]acetylcholine, but this inhibitory effect does not appear to be due to the activation of the D-2 dopamine receptor since it was not reversed by the selective D-2 dopamine antagonist, sulpiride. Additionally, the uncharged monomethylsulfide and sulfoxide dopamine analogs were found to antagonize the ability of apomorphine to inhibit the K+-evoked release of [3H]acetylcholine, but this antagonistic effect does not appear to be due to the reversible blockade of the D-2 dopamine receptor since it was not reduced by increasing the concentration of apomorphine. Therefore, while the permanently uncharged analogs of dopamine appear to bind to the high-affinity state of the D-2 dopamine receptor, they are not dopamine agonists or antagonists at the striatal D-2 dopamine receptor involved in regulating the release of acetylcholine. These results suggest that a positive charge may be a requirement for the activation of the striatal D-2 dopamine receptor.

Acetylcholine↗
PubMed1988

Holes in clear lenses demonstrate a pinhole effect.

This study describes a new variant of the pinhole principle. Holes drilled in clear plastic lenses held in combination with a blurring lens can overcome the blurring effect much as a traditional pinhole. Specifically, this study shows how holes of different diameter placed in lenses of different spherical power can improve visual acuity that has been degraded by a series of blurring spherical lenses. In general, the hole in the clear lens improves visual acuity for progressively stronger blurring lenses.

Cyclopentolate↗
PubMed1988

Achondroplasia with ankylosing spondylitis.

A 41-year-old-white man with achondroplasia has been followed intermittently since age 27. During this time, he has complained of neck and back pain with limited mobility in both. Other problems have included temporomandibular joint pain, dysuria without apparent urinary tract infection iritis, anemia, and an elevated gamma globulin fraction. Recently he returned to the clinic complaining of rigidity of the entire spine. Radiographs showed complete fusion of the sacroiliac joints and fusion of the cervical vertebral bodies and apophyseal joints, consistent with ankylosing spondylitis. He was found to be HLA B-27 positive. This case illustrates the importance of considering other diseases whenever atypical orthopedic problems arise in patients with a bone dysplasia.

Achondroplasia↗
PubMed1988

Unexpected dystocia secondary to a fetal sacrococcygeal teratoma: a successful outcome.

Sacrococcygeal teratoma is a rare cause of dystocia. With recent advances in perinatal care, particularly the increasing use of maternal ultrasound, it is unlikely that unexpected dystocia secondary to this tumor will be seen by many physicians. Recent reports of this type of dystocia are rare and infant mortality secondary to it is high. However, if and when encountered, such dystocia need not imply a bad prognosis for either mother or infant. This is a report of successful management of one case as well as a presentation of recently reported cases and recommendations for management.

Adult↗
PubMed1988

Western blot analysis of serum antibody reactivity with human melanoma cell antigens in alopecia areata and vitiligo.

Antibody reactivity to melanocyte-derived cells was investigated in patients with alopecia areata or totalis by use of Western blot analysis of detergent-solubilized membrane antigens of a human melanoma cell line, M14. Reactivity was detected in the sera of 9 of 27 alopecia areata or totalis patients, 8 of 13 vitiligo patients, and 6 of 24 normal control subjects. Significant differences between patient and control sera were found in the number and distribution of antibody specificities detected. In vitiligo sera, there was an increased prevalence of reactivity to a melanoma antigen of 52,000 mol wt. In contrast, the predominant specificities in alopecia areata sera were for antigens of 74,500 and 70,800 mol wt, and the majority of positive sera were from patients with total hair loss. These findings suggest that autoreactivity to pigmented cells occurs in certain patients with alopecia areata or totalis.

Alopecia↗
PubMed1988

The kallikrein kinin system in pulmonary lavage fluid of reserpinized rats.

Kallikrein content in lavage of the respiratory tract was determined by a specific RIA. The results show an immunological identity of the lung kallikrein with the standard rat urinary kallikrein. The levels of immunoreactive lung fluid kallikrein were significantly lower in rats injected with reserpine.

Animals↗
PubMed1988

Coagulase-negative staphylococcal endophthalmitis. Increase in antimicrobial resistance.

The predicted sensitivities of common organisms guide initial antibiotic therapy in endophthalmitis. The authors suspected a change in the expected sensitivity of coagulase-negative staphylococci when three cases of endophthalmitis due to multiply resistant organisms failed to respond to intravitreal cefazolin and gentamicin. The authors reviewed 48 cases from 1982 to 1986, compared these with 28 cases from 1973 to 1981, they found increased resistance to gentamicin (35 versus 0%, P less than 0.05) and increased resistance to methicillin (27 versus 19%). Eight cases were resistant to both antibiotics, including the three clinical failures. Final vision was unrelated to antimicrobial resistance. Since cephalosporins may be ineffective clinically against methicillin-resistant staphylococci, concomitant gentamicin resistance may render intravitreal cefazolin and gentamicin inadequate for their treatment. No isolates were resistant to vancomycin. Vancomycin and aminoglycoside, used intravitreally in the initial management of endophthalmitis, would be anticipated to provide better coverage than cefazolin and aminoglycoside for endophthalmitis due to the staphylococci, as well as for infections due to streptococcal and bacillus species.

Aged↗
PubMed1988

Lymphogranuloma venereum conjunctivitis with a marginal corneal perforation.

The authors have recently treated a case of Parinaud's oculoglandular syndrome due to Chlamydia trachomatis serotype L2, a causative agent of lymphogranuloma venereum (LGV). The ocular manifestations included a mixed papillary-follicular conjunctivitis with fleshy superior limbal lesions in both eyes. A superior marginal corneal perforation requiring a therapeutic corneal graft was present in the right eye. The patient had vaginitis, inguinal lymphadenopathy, a history of Sjögren's syndrome, and seropositivity to human immunodeficiency virus (HIV). The ocular disease resolved completely after 6 weeks of oral tetracycline therapy.

Adolescent↗
PubMed1988

Increased urinary methylmalonic acid excretion in breast-fed infants of vegetarian mothers and identification of an acceptable dietary source of vitamin B-12.

Increased urinary methylmalonic acid (UMMA) concentrations might indicate vitamin B-12 deficiency. Our study tested the hypothesis that elevated UMMA in breast-fed infants is associated with decreased maternal serum B-12 concentrations. UMMA concentrations were measured in 17 vegetarian mothers and their infants and in six infants of nonvegetarian mothers. Serum vitamin B-12 concentrations were determined in all mothers. Range of UMMA for vegetarian infants (3-924 mcg/mg [2.6-790.9 mumol/mmol] creatinine) was much broader than that for omnivorous infants (2-25 mcg/mg [1.7-21.4 mumol/mmol] creatinine). Maternal UMMA and serum vitamin B-12 were negatively correlated (r = -0.700, p = 0.003). Infant UMMA concentrations correlated positively with maternal UMMA concentrations (r = 0.686, p = 0.003) and inversely with maternal serum vitamin B-12 concentrations (r = -0.681, p less than 0.001). In three infants with high UMMA concentrations, vitamin B-12 treatment (oral B-12, vitamin B-12 injection, or a modification of maternal diet within the vegetarian philosophy) led to an abrupt decrease of UMMA.

Adult↗
PubMed1988

Androgen regulation of murine beta-glucuronidase expression: identification and characterization of a nonresponse variant.

One of the major features of beta-glucuronidase (GUS) expression in inbred strains of the house mouse, Mus musculus, is the responsiveness of this enzyme to androgen stimulation in tubule cells of the kidney. Both GUS-specific and nonspecific mutations have been described which define genes that serve to control this response. During examination of the expression of GUS in the interbreeding subspecies, Mus hortulanus, a new GUS haplotype was uncovered that is characterized, in part, by a lack of GUS response to androgen stimulation in an apparently responsive kidney. Blot hybridization analyses of kidney RNA with a radiolabeled murine GUS cDNA shows this lack of response to be reflected in GUS mRNA levels. The difference in heat stability of GUS activity between M. hortulanus and a responsive inbred strain, ICR/Ha, was utilized to assess the contribution of each parent to kidney levels of GUS in androgen-treated and -untreated F1 progeny of these strains. The results, together with preliminary genetic studies, suggest that the element controlling this responsiveness (or the lack thereof) is cis-active and tightly linked to the GUS structural gene on chromosome 5. It is not known whether this element is identical to another GUS-specific, cis-active element, Gus-r, which also controls the androgen response of GUS in mouse kidney.

Androgens↗
PubMed1988

Hemodynamic effects of doxacurium chloride in patients receiving oxygen sufentanil anesthesia for coronary artery bypass grafting or valve replacement.

Doxacurium chloride is an investigational long-acting neuromuscular blocking drug, which has been shown to be devoid of cardiovascular side effects when administered in modest doses to healthy patients. This is the first hemodynamic study of doxacurium in adult patients with cardiac disease. Forty-one patients scheduled to undergo cardiac surgery were studied. Anesthesia consisted of induction with midazolam 0.2-0.3 mg/kg and sufentanil 0.01-0.03 mg followed by an infusion of sufentanil at 0.03-0.06 mg.min-1. Baseline hemodynamic data were collected during a stable state of sufentanil anesthesia. Doxacurium was then administered in doses of 1, 2, or 3 times its ED95 of 0.025 mg/kg. Hemodynamic measurements were repeated at 2, 5, and 10 min after doxacurium injection in the absence of surgical stimulation. An additional group of control patients received saline instead of doxacurium. Baseline hemodynamic measurements were similar among groups. There was a slight decrease in heart rate in all groups over time. However, there was no significant difference between the groups of patients receiving doxacurium and the control group in which the heart rate decreased progressively from 52 beats/min at baseline to 49 beats/min 10 min after doxacurium administration. At no time was there any significant change in mean arterial pressure, right atrial pressure, or cardiac output. Likewise derived hemodynamic variables including cardiac index, stroke volume, and pulmonary vascular resistance were unchanged. In addition to the decrease in heart rate, the hemodynamic changes, which reached statistical significance, were clinically insignificant and occurred predominantly in the group of patients receiving doxacurium 0.08 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗