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Biomedical subjects

R F Miller

Publications and source records attributed to R F Miller.

At least 199 records · Page 11Linked to original sources
PubMed1994

67Ga scintigraphy in HIV antibody positive patients; a review of its clinical usefulness.

We reviewed the results of 67Ga scintigraphy in HIV antibody positive patients in order to determine how the result affected management. Case records of 37 HIV antibody positive patients undergoing 41 67Ga scintigraphic studies over a 31 month period were examined. New and additional information was provided by 67Ga scintigraphy in 22 studies (53%). In 13 studies (32%) there was a positive effect on patient management. 67Ga scintigraphy was most useful in differentiating Pneumocystis carinii pneumonia from Kaposi's sarcoma in the chest and for the diagnosis of unsuspected lymphoma. Factors which reduced the effectiveness of 67Ga scintigraphy included empirical use of antibiotics in patients with suspected infection and the low specificity of the test.

Adult↗
PubMed1994

Localized cerebral proton MR spectroscopy in HIV infection and AIDS.

PURPOSE: To document differences in the cerebral proton MR spectra of patients with early and late stages of human immunodeficiency virus (HIV) infection. METHOD: We studied the relative N-acetyl-aspartate (NAA) levels by localized proton spectroscopy of the parietooccipital region of the brain in 43 HIV-seropositive patients, including 26 with an acquired immunodeficiency syndrome (AIDS)-defining diagnosis, and in eight control subjects. RESULTS: Reduced relative NAA levels were shown in those HIV-1-seropositive patients: 1) with AIDS against HIV-1-seropositive patients without AIDS (P < .04); 2) with HIV-1-associated cognitive/motor complex against neurologically healthy patients (P < .007); 3) with encephalopathic changes on MR against those with normal imaging (P < .001); and 4) on follow-up against their results on initial study (P < .03). CONCLUSIONS: By clinical (Centers for Disease Control classification) and radiologic (MR evidence of white-matter disease) criteria indicating late-stage HIV infection, reduced relative levels of NAA have been demonstrated. Spectroscopic abnormalities can be quantitatively tracked with time. This paper demonstrates the clinical use of detecting NAA as a putative in vivo measure of the neuronal loss that has been demonstrated in postmortem studies of patients with AIDS. This neuronal loss, which is believed to underlie the HIV-1-associated cognitive/motor complex, is thought to be attributable directly or indirectly to the presence of HIV in the brain. Proton spectroscopy may serve as a quantitative noninvasive indicator of this aspect of cerebral involvement in HIV disease.

AIDS Dementia Complex↗
PubMed1993

Aerosols for therapy and diagnosis.

Aerosols are defined as any mixture of solid or liquid particles/droplets that are stable as a suspension in air. Aerosols influence the lives of a large majority of the population. A proportion of particulates exacerbate or induce lung disease. Other aerosols are used in the prevention or control of lung disease or in the investigation of disease. This review covers the mechanisms of deposition of aerosols, the production and sizing of aerosols, factors affecting the variability in output from nebulisers and the use of radionuclides in defining drug deposition from therapeutic nebulisers.

Adult↗
PubMed1993

Tuberculosis and AIDS: is the white plague up and coming?

We have studied the effect of the HIV epidemic on the incidence of tuberculosis in an inner city area of London which has a high incidence of acquired immunodeficiency syndrome (AIDS). During the period 1985-1991, there was a steady increase in the number of new AIDS cases, whilst the numbers of notifications and laboratory isolates of Mycobacterium tuberculosis remained largely unchanged. Before 1990 there were few cases of tuberculosis in HIV-infected individuals but in the past 2 years there has been a marked increase. In 44% of patients, the site of infection was pulmonary, in 39% extrapulmonary and in 17% pulmonary and extrapulmonary. There were no previous manifestations of immunodeficiency in 58% of patients. This is the first study to show an association between tuberculosis and HIV in the U.K. and supports the suggestion that there is an increased incidence of tuberculosis in patients with HIV infection who are not intravenous drug users.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Liposomal doxorubicin for treatment of AIDS-related Kaposi's sarcoma.

Sixteen patients with advanced AIDS-related Kaposi's sarcoma received liposomal doxorubicin (Doxil, Liposome Technology, Menlo Park, California) at 20 mg/m2 every 2 or 3 weeks in an open label study, and were evaluated for efficacy and toxicity. Eleven patients achieved a partial remission and five had stable disease. The median time to achieve a maximum response was two cycles (range 1-3) and the median duration of response was 14 weeks (range 6-30). Myelosuppression was the commonest adverse event; one patient was withdrawn because of neutropenia. Other adverse events were uncommon and mild. Liposomal doxorubicin is an effective and safe single agent treatment for advanced AIDs-related Kaposi's sarcoma.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Paranasal sinus disease in HIV antibody positive patients.

OBJECTIVE: To investigate the prevalence of radiologically-diagnosed paranasal sinus disease in HIV-1 seropositive patients. SUBJECTS AND SETTING: 476 patients admitted to a dedicated inpatient unit for HIV and AIDS at the Middlesex Hospital, London, between September 1988 and February 1992. DESIGN: Retrospective review of patients' case notes and radiological records. RESULTS: 30 patients (6.3%) had radiological evidence of paranasal sinus disease. At the time of admission, sinusitis was in the differential diagnosis in only 12 of the 30 patients; 13 patients were initially diagnosed as having meningitis. Pseudomonas aeruginosa was the causative organism in four patients, all of whom had advanced HIV disease. All four responded to appropriate antibiotics but had early relapse of infection. CONCLUSIONS: Sinusitis is an important and under-recognised cause of morbidity in patients with HIV disease.

Adult↗
PubMed1993

Detection of varicella-zoster virus DNA using the polymerase chain reaction in an immunocompromised patient with transverse myelitis secondary to herpes zoster.

A case of herpes zoster transverse myelitis is described in which the clinical diagnosis was confirmed by demonstrating the presence of varicella-zoster virus (VZV) DNA in the cerebrospinal fluid (CSF) by amplification using the polymerase chain reaction. This case illustrates the potential role of the selective amplification of VZV DNA from CSF in contributing to the diagnosis of neurological complications associated with VZV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Histologically atypical Pneumocystis carinii pneumonia.

BACKGROUND: Infection with Pneumocystis carinii typically results in a pneumonia which histologically is seen to consist of an eosinophilic foamy alveolar exudate associated with a mild plasma cell interstitial infiltrate. Special stains show that cysts of P carinii lie within the alveolar exudate. Atypical histological appearances may occasionally be seen, including a granulomatous pneumonia and diffuse alveolar damage. In these patients the clinical presentation may be atypical and results of investigations negative unless lung biopsies are performed and tissue obtained for histological examination. METHODS: The incidence and mode of presentation of histologically atypical pneumocystis pneumonia was studied in a cohort of HIV-I antibody positive patients. RESULTS: Over a 30 month period 138 patients had pneumocystis pneumonia, of whom eight (6%) had atypical histological appearances which were diagnosed (after negative bronchoalveolar lavage) by open lung biopsy in five, percutaneous biopsy in one, and at post mortem examination in two. Atypical appearances included granulomatous inflammation in four patients, "pneumocystoma" in two (one also had extrapulmonary pneumocystosis), bronchiolitis obliterans organising pneumonia in one patient, diffuse alveolar damage and subpleural cysts in one (who also had intrapulmonary cytomegalovirus infection), and extrapulmonary pneumocystosis in two patients. CONCLUSIONS: Various atypical histological appearances may be seen in pneumocystis pneumonia. Lung biopsy (either percutaneous or open) should be considered when bronchoalveolar lavage is repeatedly negative and evidence of P carinii should be sought, by use of special stains, in all lung biopsy material from HIV-I antibody positive patients.

AIDS-Related Opportunistic Infections↗
PubMed1993

Changing patterns of respiratory disease in HIV positive patients in a referral centre in the United Kingdom between 1986-7 and 1990-1.

BACKGROUND: Respiratory illness is a significant contributor to morbidity and mortality in patients with human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS). It has been suggested that Pneumocystis carinii pneumonia is no longer the most frequent cause of respiratory disease in this group because of widespread use of prophylaxis and anti-retroviral drugs. METHODS: A retrospective comparison of the diagnoses in HIV 1 antibody positive patients with respiratory illness admitted to a major UK centre in 1986-7 and 1990-1 was carried out to identify changes in patterns of respiratory disease. RESULTS: In the 1986-7 period there were 73 patients, of whom none received zidovudine or prophylaxis for pneumocystis pneumonia while in the 1990-1 period there were 122 patients. One hundred and ninety patients (98%) were male homosexuals. Pneumocystis pneumonia remained the commonest respiratory disease, comprising 68% of all diagnoses in the 1986-7 period and 48% in the 1990-1 period. Bacterial infections (bronchitis and pneumonia) were seen more commonly in the 1990-1 period (23%) than in the 1986-7 period (14%), as was pulmonary Kaposi's sarcoma (12% in 1990-1 and 4% in 1986-7). Mycobacterial infection remained uncommon (4% in 1986-7 and 6.5% in 1990-1). CONCLUSION: Despite widespread use of zidovudine and prophylaxis, pneumocystis pneumonia remains the commonest respiratory disease in homosexual men.

Bronchitis↗
PubMed1993

Proton spectroscopy of the brain in HIV infection: correlation with clinical, immunologic, and MR imaging findings.

Abnormalities at cerebral proton spectroscopy occur in patients with the acquired immunodeficiency syndrome (AIDS). N-acetyl aspartate (NAA) is believed to be a neuronal marker, and neuronal loss is thought to underlie the human immunodeficiency virus (HIV)-associated cognitive/motor complex. The proton spectra in 103 HIV-seropositive patients and 23 control subjects were compared and correlated with clinical, immunologic, and radiologic measures of HIV infection. Significant (P < .05) reductions in the mean NAA/choline (Cho) and NAA/creatine (Cr) ratios were seen in patients with immune suppression and neurologic signs. Significant increases in the Cho/Cr ratios were seen in patients with low CD4 lymphocyte counts and abnormal magnetic resonance (MR) images. Reduced NAA ratios correlated with diffuse but not focal MR imaging abnormalities. Combined MR imaging and spectroscopy provides closer relationships to clinical and immunologic measures of disease than either modality alone. Spectroscopy is an adjunct to MR imaging and augments the value of an MR imaging study.

Adult↗
PubMed1993

Properties of synaptic transmission from photoreceptors to bipolar cells in the mudpuppy retina.

1. Simultaneous, whole-cell recordings were obtained from synaptically coupled photoreceptor/bipolar cell pairs, by the use of direct visualization in a superfused, mudpuppy retinal slice preparation. 2. OFF-bipolar cells (BPs) generated sign-conserving responses when extrinsic current was injected into rods and cones, whereas ON-BPs generated a sign-reversing response. OFF-BPs (n = 24) responded faster than ON-BPs (n = 12), in terms of response latency (27.8 vs. 80.6 ms) and peak response times (50.5 vs. 159.8 ms) when current was injected into photoreceptors. We did not detect any significant difference between rod- versus cone-mediated latency or peak response times in the ON- and OFF-BP subtypes. 3. Rod and cone inputs to OFF-BPs were blocked by kynurenic acid (Kyn), but the doses required were significantly higher for rod inputs: the IC50 (the concentration at which an antagonist blocks 50% of the responses) for Kyn was 0.3 mM for cone inputs and 1 mM for rod inputs. 4. Rod inputs to OFF-BPs showed the same Kyn sensitivity as rod inputs to horizontal cells (HCs). However, cone inputs to HCs (IC50 < 200 microM) were more sensitive to Kyn than those to OFF-BPs. 5. The pharmacological studies presented here, together with previous studies, suggest that the sign-conserving pathway in the outer plexiform layer of the mudpuppy retina involves at least three subtypes of glutamate receptors: 1) cone-activated receptors of HCs; 2) cone-activated receptors of OFF-BPs; and 3) rod-activated receptors found in HCs and BPs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminobutyrates↗
PubMed1993

Membrane currents evoked by excitatory amino acid agonists in ON bipolar cells of the mudpuppy retina.

1. Whole-cell patch-clamp recordings were obtained from ON bipolar cells in a retinal slice preparation of the mudpuppy, Necturus maculosus. The effects of excitatory amino acid (EAA) agonists applied in the presence of cobalt (2-5 mM) were examined. 2. At the holding potential of -50 mV, L-2-amino-4-phosphonobutanoic acid (L-AP4, 5-10 microM) evoked an outward current accompanied by a conductance decrease. The zero current potential of the L-AP4-evoked current was near 0 mV independent of whether the intracellular Ringer solution contained CsCl or CsCH3SO4. The currents evoked by light were also accompanied by a conductance decrease and reversed near 0 mV. Replacing external sodium with choline or N-methyl-D-glucamine generated an outward current and suppressed the response to L-AP4. The response to L-AP4 was enhanced by removing extracellular calcium and suppressed by increasing extracellular calcium. These results indicate that L-AP4 closes nonspecific cation channels that are blocked by extracellular calcium. 3. In 2 mM cobalt, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA, 50-100 microM) evoked membrane currents that were accompanied by a conductance increase. AMPA-evoked currents exhibited a significant chloride dependence and were suppressed by gamma-aminobutyric acid-A (GABAA) antagonists bicuculline and picrotoxin; a GABA uptake blocker, nipecotic acid; and a glycine antagonist, strychnine. AMPA-induced currents were virtually absent in the presence of 5 mM cobalt and nominally 0 mM extracellular calcium. These results indicate that the conductance increase induced by AMPA in the presence of 2 mM cobalt is largely the result of calcium-dependent synaptic inputs onto GABAA and glycine receptors of ON bipolar cells. 4. N-methyl-D-aspartic acid (250 microM) was ineffective when applied in the presence of 100 microM cadmium or 2 mM cobalt. 5. 1S,3R/1R,3S-1-aminocyclopentane-1,3-dicarboxylic acid (100-200 microM) evoked an outward current accompanied by a conductance decrease and appears to be an agonist at the L-AP4 receptor. 6. The findings of this study suggest that the only type of EAA receptor in mudpuppy ON bipolar cells is the L-AP4 receptor and that L-AP4 receptor activation results in the closing of nonspecific cation channels that are blocked by extracellular calcium.

Amino Acids↗
PubMed1993

Oropharyngeal samples for detection of Pneumocystis carinii by DNA amplification.

Pneumocystis carinii pneumonia is a major complication of T-lymphocyte immune deficiency. Restriction of the disease to the alveolar spaces and failure to culture R. carinii has hindered simple diagnostic methods. We have developed a specific DNA amplification method for P. carinii and shown diagnostic sensitivity and specificity exceeding 95% for pneumocystis pneumonia when applied to bronchoscopic lavage and hypertonic saline induced sputum. We here report application of DNA amplification to simple oropharyngeal samples in 31 HIV-positive patients with respiratory illness. P. carinii-specific DNA was detected in 10 of 18 (56%) patients with pneumocystis pneumonia by ethidium bromide stained gels and 14 of 18 (78%) patients by the more sensitive technique of oligoblotting. P. carinii DNA was not detected in samples from 13 patients with other respiratory diagnoses. An oropharyngeal sample offers a simple specimen for detecting P. carinii by DNA amplification; refinements of technique and calibration may allow its development for accurate diagnostic and epidemiological work.

AIDS-Related Opportunistic Infections↗
PubMed1993

Indium-111-labeled polyclonal human immunoglobulin: identifying focal infection in patients positive for human immunodeficiency virus.

Pooled human immunoglobulin labeled with indium-111 (111In-HIgG) was used to identify the presence and extent of infection in patients positive for human immunodeficiency virus (HIV), presenting with either symptoms and/or signs of acute chest infection or with pyrexia without localizing signs or symptoms. Fifty-five studies were performed in 51 patients with suspected chest infection or pyrexia without localizing signs. Of these, 111In-HIgG identified intrapulmonary accumulation in 17 patients with Pneumocystis carinii pneumonia, eight with bacterial pneumonia, five with cytomegalovirus pneumonia, three with pulmonary Mycobacterium avium intracellulare infection and one with a fungal pneumonia. There was no intrapulmonary accumulation of 111In-HIgG in five patients with bronchopulmonary Kaposi's sarcoma and in three patients with intrathoracic lymphoma. Quantification of lung/heart activity was significantly increased (p < 0.05) in patients with active chest infection compared with those with intrapulmonary tumor or no active lung pathology. Indium-111-HIgG scintigraphy also localized at 14 sites of extrapulmonary infection, including six patients with colitis. There were no false-negative studies but false-positive uptake was seen in four studies. These results confirm that 111In-HIgG correctly identifies the presence and extent of infection in patients positive for HIV antibody.

AIDS-Related Opportunistic Infections↗
PubMed1992

Catecholamine effects on dissociated tiger salamander Muller (glial) cells.

Dissociated Muller (glial) cells from the neotenous tiger salamander retina respond electrogenically and rheogenically to three putative catecholamine (CA) neurotransmitters, epinephrine, norepinephrine and dopamine. All 3 CAs stimulate a net inward current and an increase in input resistance (Rn). The Muller cell response to the CAs is concentration dependent. At high concentrations ascorbate, an antioxidant used to protect the CAs from oxidation, stimulated a net outward current and a decrease in Rn. When the effects of ascorbate were considered, the CA response at 1 mM was no larger than the response at 100 microM, indicating that 100 microM CA maximally stimulated the Muller cell response.

Animals↗
PubMed1992

Pulmonary nuclear medicine.

This article reviews the contribution made by nuclear imaging to the assessment, diagnosis and monitoring of patients with respiratory disease. It focuses on several specific areas including the diagnosis of pulmonary embolism, the investigation of intrapulmonary infection and neoplasm and the role of positron emission tomography (PET) scanning.

HIV Seropositivity↗