Biomedical subjects

M L Miller

Publications and source records attributed to M L Miller.

At least 55 records · Page 3Linked to original sources

PubMed1999

HIV-associated risk factors among young Canadian Aboriginal and non-Aboriginal men who have sex with men.

Young Aboriginal men face marginalization distinct in cause but similar in pattern to those seen among men who have sex with men (MSM) and may be at increased risk for HIV infection. We compared sociodemographic characteristics and risk taking behaviours associated with HIV infection among MSM of Aboriginal and non-Aboriginal descent. Data for this comparison were gathered from baseline questionnaires completed by participants in a cohort study of young MSM. Data collection included: demographic characteristics such as age, length of time residing in the Vancouver region, housing, employment, income and income sources; mental health and personal support; instances of forced sex and sex trade participation and; sexual practices with regular and casual male sex partners. Data were available for 57 Aboriginal and 624 non-Aboriginal MSM. Aboriginal MSM were significantly less likely to be employed, more likely to live in unstable housing, to have incomes of <$10,000 and to receive income assistance than non-Aboriginals (all P<0.01). Aboriginals also had higher depression scores (P<0.01), were more likely to report non-consensual sex (P=0.03), sexual abuse during childhood (P=0.04) and having been paid for sex (P<0.01). In the past year they were no more likely to have had sex with a male partner they knew to be HIV positive, to have had more than 50 male partners or to have unprotected anal insertive or receptive intercourse with their male partners (all P>0.05). Our data indicate that among MSM, Aboriginal men are at increased risk of antecedent risk factors for HIV infection including sexual abuse, poverty, poor mental health and involvement in the sex trade.

Adolescent↗

PubMed1998

Phenotype resembling Gitelman's syndrome in mice lacking the apical Na+-Cl- cotransporter of the distal convoluted tubule.

Mutations in the gene encoding the thiazide-sensitive Na+-Cl- cotransporter (NCC) of the distal convoluted tubule cause Gitelman's syndrome, an inherited hypokalemic alkalosis with hypomagnesemia and hypocalciuria. These metabolic abnormalities are secondary to the deficit in NaCl reabsorption, but the underlying mechanisms are unclear. To gain a better understanding of the role of NCC in sodium and fluid volume homeostasis and in the pathogenesis of Gitelman's syndrome, we used gene targeting to prepare an NCC-deficient mouse. Null mutant (Ncc-/-) mice appear healthy and are normal with respect to acid-base balance, plasma electrolyte concentrations, serum aldosterone levels, and blood pressure. Ncc-/- mice retain Na+ as well as wild-type mice when fed a Na+-depleted diet; however, after 2 weeks of Na+ depletion the mean arterial blood pressure of Ncc-/- mice was significantly lower than that of wild-type mice. In addition, Ncc-/- mice exhibited increased renin mRNA levels in kidney, hypomagnesemia and hypocalciuria, and morphological changes in the distal convoluted tubule. These data indicate that the loss of NCC activity in the mouse causes only subtle perturbations of sodium and fluid volume homeostasis, but renal handling of Mg2+ and Ca2+ are altered, as observed in Gitelman's syndrome.

Aldosterone↗

PubMed1998

Balance and hearing deficits in mice with a null mutation in the gene encoding plasma membrane Ca2+-ATPase isoform 2.

Plasma membrane Ca2+-ATPase isoform 2 (PMCA2) exhibits a highly restricted tissue distribution, suggesting that it serves more specialized physiological functions than some of the other isoforms. A unique role in hearing is indicated by the high levels of PMCA2 expression in cochlear outer hair cells and spiral ganglion cells. To analyze the physiological role of PMCA2 we used gene targeting to produce PMCA2-deficient mice. Breeding of heterozygous mice yielded live homozygous mutant offspring. PMCA2-null mice grow more slowly than heterozygous and wild-type mice and exhibit an unsteady gait and difficulties in maintaining balance. Histological analysis of the cerebellum and inner ear of mutant and wild-type mice revealed that null mutants had slightly increased numbers of Purkinje neurons (in which PMCA2 is highly expressed), a decreased thickness of the molecular layer, an absence of otoconia in the vestibular system, and a range of abnormalities of the organ of Corti. Analysis of auditory evoked brainstem responses revealed that homozygous mutants were deaf and that heterozygous mice had a significant hearing loss. These data demonstrate that PMCA2 is required for both balance and hearing and suggest that it may be a major source of the calcium used in the formation and maintenance of otoconia.

Animals↗

PubMed1998

Targeted disruption of the murine Na+/H+ exchanger isoform 2 gene causes reduced viability of gastric parietal cells and loss of net acid secretion.

Multiple isoforms of the Na+/H+ exchanger (NHE) are expressed at high levels in gastric epithelium, but the physiological role of individual isoforms is unclear. To study the function of NHE2, which is expressed in mucous, zymogenic, and parietal cells, we prepared mice with a null mutation in the NHE2 gene. Homozygous null mutants exhibit no overt disease phenotype, but the cellular composition of the oxyntic mucosa of the gastric corpus is altered, with parietal and zymogenic cells reduced markedly in number. Net acid secretion in null mutants is reduced slightly relative to wild-type levels just before weaning and is abolished in adult animals. Although mature parietal cells are observed, and appear morphologically to be engaged in active acid secretion, many of the parietal cells are in various stages of degeneration. These results indicate that NHE2 is not required for acid secretion by the parietal cell, but is essential for its long-term viability. This suggests that the unique sensitivity of NHE2 to inhibition by extracellular H+, which would allow upregulation of its activity by the increased interstitial alkalinity that accompanies acid secretion, might enable this isoform to play a specialized role in maintaining the long-term viability of the parietal cell.

Acids↗

PubMed1998

Fast analysis of drugs in a single hair.

A new method for the fast screening of cocaine and 6-monoacetylmorphine (6-MAM) in a single hair, using gas chromatography/mass spectrometry (GC/MS), is described. The analyses are conducted in less than 10 min with minimal sample preparation. The novel method combines the ChromatoProbe direct sample introduction device for intrainjector thermal extraction, fast GC separation, a supersonic molecular beam GC/MS interface and hyperthermal surface ionization (HSI). The technique has been successfully employed for the detection of cocaine in as little as a 1-mm section of hair using selected ion monitoring (SIM). Unambiguous full scan mass spectra of cocaine and 6-MAM were obtained on a single hair for cocaine and heroin users, respectively. HSI was found to be almost 3 orders of magnitude more selective than electron impact ionization for cocaine compared with the major hair constituents, with a minimum detected concentration of approximately 10 ppb in the SIM mode. Results obtained for 12 drugs users showed full qualitative agreement with similar results using rigorous solvent extraction followed by electrospray-liquid chromatography/mass spectrometry analysis. However, quantitative studies showed only partial agreement. No false positives were observed for 10 drugs free subjects. This method enables fast drug monitoring along the hair length which permits time correlation studies.

Adult↗

PubMed1998

Renal and intestinal absorptive defects in mice lacking the NHE3 Na+/H+ exchanger.

NHE3 is one of five plasma membrane Na+/H+ exchangers and is encoded by the mouse gene Slc9a3. It is expressed on apical membranes of renal proximal tubule and intestinal epithelial cells and is thought to play a major role in NaCl and HCO3- absorption. As the distribution of NHE3 overlaps with that of the NHE2 isoform in kidney and intestine, the function and relative importance of NHE3 in vivo is unclear. To analyse its physiological functions, we generated mice lacking NHE3 function. Homozygous mutant (Slc9a3-/-) mice survive, but they have slight diarrhoea and blood analysis revealed that they are mildly acidotic. HCO3- and fluid absorption are sharply reduced in proximal convoluted tubules, blood pressure is reduced and there is a severe absorptive defect in the intestine. Thus, compensatory mechanisms must limit gross perturbations of electrolyte and acid-base balance. Plasma aldosterone is increased in NHE3-deficient mice, and expression of both renin and the AE1 (Slc4a1) Cl-/HCO3- exchanger mRNAs are induced in kidney. In the colon, epithelial Na+ channel activity is increased and colonic H+,K+-ATPase mRNA is massively induced. These data show that NHE3 is the major absorptive Na+/H+ exchanger in kidney and intestine, and that lack of the exchanger impairs acid-base balance and Na+-fluid volume homeostasis.

Animals↗

PubMed1998

The morphological and spectral phenotype of apoptosis in HeLa cells varies following exposure to UV-C and the addition of inhibitors of ICE and CPP32.

Numerous extra- and intracellular factors, including UV radiation, can initiate a programme of cell death by apoptosis. While apoptosis is commonly defined morphologically, the relationships between morphology and molecular events are not well established. To investigate these relationships in HeLa cells, eight morphometric criteria for cell proliferation and damage and 10 criteria for apoptotic phenotype were examined using light microscopy, and corroborated by ultrastructure and spectral imaging. They were identified (1) during a time course after irradiation with 0, 10 or 30 J/m2 UV-C; (2) after separation of apoptotic from normal cells on a Percoll gradient; and (3) after irradiation with UV-C plus perturbation of the apoptotic pathway by treatment with inhibitors of two caspases, ICE and CPP32. The number of cells in apoptosis increased in a dose-dependent manner after UV-C treatment. Centrifugation of irradiated cells on a Percoll gradient increased the collection of apoptotic cells tenfold. The stereotypical apoptotic phenotype, in which cells have deep cytoplasmic blebbing and highly condensed DNA, comprised only a few percent of all apoptosis, and was rarely seen in groups receiving caspase inhibitors. The most common apoptotic phenotype was a rounded cell with large spherical nucleolus and associated DNA. After treatment with UV-C plus inhibitors the apoptotic index was decreased by about 30% compared to UV-C radiation alone. These apoptotic cells had dark spherical cytoplasm with small blebs, greatly increased numbers of cytoplasmic ribosomes, abundant nucleolar material with a large separate granular component, and chromatin condensed at the nuclear membrane. Using the technique of spectral imaging, it was found that the spectrum obtained from the granular component of the nucleolus, which was elevated in apoptotic cells treated with UV-C plus inhibitors, was similar to the dense accumulation of ribosomes in the apoptotic cytoplasm. The data indicate that spectral imaging may be a useful tool for identifying and characterizing variations in the apoptotic process, and that the caspase inhibitors used here do not completely abolish UV-C induced apoptosis, but rather alter its incidence and progression.

Amino Acid Chloromethyl Ketones↗

PubMed1998

Comparative analysis of interphase FISH and RT-PCR to detect bcr-abl translocation in chronic myelogenous leukemia and related disorders.

The t(9;22)(q34;q1 1) between the abl and bcr genes plays a pivotal role in the diagnosis and pathogenesis of chronic myelogenous leukemia (CML). Its detection is routinely accomplished by Southern blot analysis and karyotyping. Interphase fluorescence in situ hybridization (FISH) and reverse transcriptase-polymerase chain reaction (RT-PCR) are emerging molecular techniques that offer viable alternatives. We analyzed 40 samples of peripheral blood and bone marrow (CML, 16; acute myelogenous leukemia, 6; acute lymphoblastic leukemia [ALL], 1; chronic lymphoblastic leukemia, 2; myelodysplasias, 4; myeloproliferative disorders, unclassified, 3; nonleukemic hematologic malignancies, 3; hypercellular bone marrow, 1; normal control samples, 2; and K562 cell line samples, 2) for the presence of bcr-abl fusion gene and its messenger RNA (mRNA) transcript by FISH and RT-PCR, respectively. We compared the results with results of Southern blot analysis and karyotyping when available. Cost analysis was performed. Thirty-three samples were evaluable by FISH; 14 of 14 evaluable CML samples and one ALL sample were positive for bcr-abl by FISH (100%). The other 15 evaluable samples were negative; 16 of 16 (100%) and 13 of 16 (81%) of CML cases were positive for bcr-abl mRNA by RT-PCR (chemiluminescent blot method) and RT-PCR (colorimetric method), respectively. The ALL sample was positive by both RT-PCR methods. All other samples were negative by RT-PCR (chemiluminescent blot method), and all but 1 case of myeloproliferative disorder tested negative by RT-PCR (colorimetric method). We conclude the utility of FISH and RT-PCR is associated with certain limitations, such as insufficient RNA for RT-PCR and the occasional absence of internal positive FISH control signals. However, each procedure offers (with a high concordance rate) a specific and cost-effective alternative to Southern blot analysis and karyotyping and improved turnaround time for the detection of bcr-abl fusion gene or its mRNA transcript.

Blotting, Southern↗

PubMed1998

The diagnostic usefulness of bone marrow cultures in patients with fever of unknown origin.

Bone marrow cultures (BMCs) and blood cultures (BCs) are frequently obtained in the evaluation of fever of unknown origin (FUO). However, the low yield of clinically significant isolates leads to questions about their cost-effectiveness. We retrospectively compared BMC with BC and studied the usefulness of bone marrow trephine biopsy (BMTB) histopathology in detecting infection in an unselected population of 61 patients with FUO, among whom 215 BMCs had been performed. For patients who had undergone BMTB, the histopathology was evaluated for granulomas and microorganisms. Only 1 BMC had a clinically significant isolate, Mycobacterium avium complex (MAC), which was also identified by BC. Rhodotorula rubra was found in the BMC of another patient and classified as a contaminant. Both patients had HIV infection. No growth occurred in BCs for the other 59 patients. Culture results for all 26 BMTB specimens were negative; 4 contained nonnecrotizing granulomas, including the case with MAC. BMCs are probably not justified for routine initial evaluation of FUO, but may be valuable after culture results for blood and easily obtainable tissues have been negative. Bone marrow histopathology and special stains for microorganisms in the absence of granulomas were noncontributory.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Eosinophilic globules in spindle cell and epithelioid cell nevi: composition and possible origin.

The presence of eosinophilic globules has been described as a helpful sign for the histologic differentiation of Spitz's nevus from malignant melanoma. The origin of these bodies is not clear, and they have been likened to Civatte or colloid bodies of lichen planus. This would suggest that they might originate from degenerating keratinocytes or melanocytes or both. These eosinophilic globules and the colloid bodies of lichen planus have been reported to be similar in that they both stain positively for type IV collagen and laminin. These previous reports have failed to include, or have not emphasized, the staining for keratin that separates these two bodies. We stained 10 spindle cell and epithelial cell (S&E) nevi for S-100 protein, keratin, vimentin, type IV collagen, and laminin. In all 10 cases of S&E nevi, the eosinophilic globules showed a positive reaction for type IV collagen and laminin and a negative reaction for keratin, S100 protein, and vimentin, unlike the colloid bodies of lichen planus, which showed a negative reaction for type IV collagen and laminin and also a strong positive reaction for keratin. These results suggest that the eosinophilic globules of Spitz's nevi are basement membrane material, perhaps synthesized by either basal cells, melanocytes or both, and are not degenerated basal cells or melanocytes.

Adolescent↗

PubMed1998

Perceived need for local anesthesia in tooth drilling among Anglo-Americans, Chinese, and Scandinavians.

This study explored ethnic differences in perceptions of pain and the need for local anesthesia for tooth drilling among age- and gender-matched Anglo-American, Mandarin Chinese, and Scandinavian dentists (n = 129) and adult patients (n = 396) using a systematic qualitative research strategy. Semistructured qualitative interviews determined: (a) the relative frequency of use or nonuse of anesthetic for similarly specified tooth drilling, (b) the reasons for nonuse of anesthetic as reported by dentists about their patients, and (c) the distribution of reasons for not using anesthetic. American dentists (n = 51) reported that about 1% of their adult patients did not use anesthetic compared with 90% among Chinese (n = 31) and 37.5% among Scandinavian dentists (n = 40). Of patients, Americans (n = 112) reported 6% nonuse of anesthetic for tooth drilling compared with 90% of 159 Chinese and 54% of 125 Scandinavians. Reasons among Anglo-Americans and Scandinavians were similar (ranked): the sensation was tolerable, to avoid numb feelings afterwards, and fear of injections. Danish patients were an exception; the fact that they had paid extra and out-of-pocket for anesthetic ranked second. In contrast, Chinese dentists made their decisions not to use anesthetics because they explained drilling as only a suan or "sourish" sensation, whereas injections were described as "painful." It was concluded that ethnic pain beliefs and differences in health-care systems are powerful psychosocial variables that affect pain perception and the perceived need for anesthetic.

Adult↗

PubMed1998

Acute pain and use of local anesthesia: tooth drilling and childbirth labor pain beliefs among Anglo-Americans, Chinese, and Scandinavians.

Differences in ethnic beliefs about the perceived need for local anesthesia for tooth drilling and childbirth labor were surveyed among Anglo-Americans, Mandarin Chinese, and Scandinavians (89 dentists and 251 patients) matched for age, gender, and occupation. Subjects matched survey questionnaire items selected from previously reported interview results to estimate (a) their beliefs about the possible use of anesthetic for tooth drilling and labor pain compared with other possible remedies and (b) the choice of pain descriptors associated with the use of nonuse of anesthetic, including descriptions of injection pain. Multidimensional scaling, Gamma, and Chi-square statistics as well as odds ratios and Spearman's correlations were employed in the analysis. Seventy-seven percent of American informants reported the use of anesthetics as possible remedies for drilling and 51% reported the use of anesthetics for labor pain compared with 34% that reported the use of anesthetics among Chinese for drilling and 5% for labor pain and 70% among Scandinavians for drilling and 35% for labor pain. Most Americans and Swedes described tooth-drilling sensations as sharp, most Chinese used descriptors such as sharp and "sourish" (suan), and most Danes used words like shooting (jagende). By rank, Americans described labor pain as cramping, sharp, and excruciating, Chinese used words like sharp, intermittent, and horrible, Danes used words like shooting, tiring, and sharp, and Swedes used words like tiring, "good," yet horrible. Preferred pain descriptors for drilling, birth, and injection pains varied significantly by ethnicity. Results corroborated conclusions of a qualitative study about pain beliefs in relation to perceived needs for anesthetic in tooth drilling. Samples used to obtain the results were estimated to approach qualitative representativity for these urban ethnic groups.

Adult↗

PubMed1997

Defective endothelium-dependent relaxation of vascular smooth muscle and endothelial cell Ca2+ signaling in mice lacking sarco(endo)plasmic reticulum Ca2+-ATPase isoform 3.

Sarco(endo)plasmic reticulum Ca2+ ATPase isoform 3 (SERCA3) is one of two Ca2+ pumps serving intracellular Ca2+ signaling pools in non-muscle tissues; however, unlike the ubiquitous SERCA2b, it exhibits a restricted cell-type distribution. Gene targeting was used to generate a mouse with a null mutation in the SERCA3 gene. Homozygous mutant mice were viable, fertile, and did not exhibit an overt disease phenotype. Because SERCA3 is expressed in arterial endothelial cells, aortic ring preparations were analyzed to determine whether it is involved in the regulation of vascular tone. Contraction-isometric force relations in response to phenylephrine or KCl, as well as relaxation produced by exposure to a nitric oxide donor, were similar in wild-type and null mutant aortas. Acetylcholine-induced endothelium-dependent relaxation of aortas after precontraction with phenylephrine was significantly reduced in homozygous mutants (61.3 +/- 5.6% in wild type, 35.4 +/- 7.3% in mutants). Ca2+ imaging of cultured aortic endothelial cells demonstrated that the acetylcholine-induced intracellular Ca2+ signal is sharply diminished in SERCA3-deficient cells and also indicated that replenishment of the acetylcholine-responsive Ca2+ stores is severely impaired. These results indicate that SERCA3 plays a critical role in endothelial cell Ca2+ signaling events involved in nitric oxide-mediated relaxation of vascular smooth muscle.

Acetylcholine↗

PubMed1997

Transglutaminase activity is increased in Alzheimer's disease brain.

Transglutaminase is a calcium-activated enzyme that crosslinks substrate proteins into insoluble, often filamentous aggregates resistant to proteases. Because the neurofibrillary tangles in Alzheimer's disease have similar characteristics, and because tau protein, the major component of these tangles is an excellent substrate of transglutaminase in vitro, transglutaminase activity and levels were measured in control and Alzheimer's disease brain. Frozen prefrontal cortex and cerebellum samples from Alzheimer's disease and control cases matched for age and postmortem interval were used in the analyses. Total transglutaminase activity was significantly higher in the Alzheimer's disease prefrontal cortex compared to control. In addition the levels of tissue transglutaminase, as determined by quantitative immunoblotting, were elevated approximately 3-fold in Alzheimer's disease prefrontal cortex compared to control. To our knowledge, this is the first demonstration that transglutaminase is increased in Alzheimer's disease brain. There were no significant differences in transglutaminase activity or levels in the cerebellum between control and Alzheimer's disease cases. Because the elevation of transglutaminase in the Alzheimer's disease samples occurred in the prefrontal cortex, where neurofibrillary pathology is usually abundant, and not in the cerebellum, which is usually spared in Alzheimer's disease, it can be suggested that transglutaminase could be a contributing factor in neurofibrillary tangle formation.

Aged↗

PubMed1997

Expression of neuregulins and their putative receptors, ErbB2 and ErbB3, is induced during Wallerian degeneration.

Schwann cell dedifferentiation and proliferation is a prerequisite to axonal regeneration in the injured peripheral nervous system. The neuregulin (NRG) family of growth and differentiation factors may play a particularly important role in this process, because these axon-associated molecules are potent Schwann cell mitogens and differentiation factors in vitro. We have examined Schwann cell DNA synthesis and the expression of NRGs and their receptors, the erbB membrane tyrosine kinases, in rat sciatic nerve, sensory ganglia, and spinal cord 0-30 d postaxotomy. Analysis of NRG cDNAs from these tissues revealed several novel splice variants and showed that cells endogenous to injured nerve express NRG mRNAs. A selective induction of mRNAs encoding the glial growth factor (GGF) subfamily of NRGs occurs in nerve beginning 3 d postaxotomy and thus coincides with the onset of Schwann cell DNA synthesis. In later stages of Wallerian degeneration, however, Schwann cell mitogenesis markedly decreases, whereas elevated GGF expression persists. Of the four known erbB kinases, Schwann cells express both erbB2 and erbB3 receptors over the entire interval studied. Expression of erbB2 and erbB3 is coordinately induced in response to axotomy, indicating that Schwann cell responses to NRGs may be modulated by changes in receptor density. Neuregulin (including transmembrane precursors) and erbB protein are associated with Schwann cells postaxotomy. Thus, in contrast to the concept of NRGs as axon-associated mitogens, our findings suggest that NRGs produced by Schwann cells themselves may be partially responsible for Schwann cell proliferation during Wallerian degeneration, probably acting via autocrine or paracrine mechanisms.

Animals↗

PubMed1997

Consensus analysis: reliability, validity, and informant accuracy in use of American and Mandarin Chinese pain descriptors.

A quantitative method for validating qualitative interview results and checking sample parameters is described and illustrated using common pain descriptions among a sample of Anglo-American and mandarin Chinese patients and dentists matched by age and gender. Assumptions were that subjects were members of a sociocultural group (e.g. ethnic or professional/lay) and answered questions independently about a monotonic domain (e.g. pain). Subjects answered 18 true/false items derived from and selected to reflect pain perceptions consistent with published and unpublished interview data. Estimates of consistency in use of descriptors within groups, validity of description, accuracy of individuals compared with others in their group, and minimum required sample size were calculated using Cronbach's alpha, factor analysis, and Bayesian probability. Ethnic and professional differences within and across groups were also tested using multidimensional scaling (MDS) and hypothesis testing. Consensus (consistency of subject response by group) was .99 among Anglo-Americans and .97 among Chinese. Mean subject accuracy was .81 for Americans and .57 for Chinese, indicating the need for larger numbers of Chinese to supplement each others' statements. However, larger numbers of subjects were recruited than actually required for each ethnic group at .95 confidence limits. MDS showed similarities in use of descriptors within ethnic groups, while there were differences (p < .001) between Chinese and American groups. Use of covalidating questionnaires that reflect results of qualitative interviews are recommended in order to estimate sample parameters such as intersubject agreement, individual subject accuracy, and minimum required sample sizes.

Adult↗

PubMed1997

The use of amplified variable number of tandem repeats (VNTR) in the detection of chimerism following bone marrow transplantation. A comparison with restriction fragment length polymorphism (RFLP) by Southern blotting.

Chimerism analysis after allogeneic bone marrow transplantation (alloBMT) allows detection of early marrow engraftment, disease relapse, and graft rejection. Our objective was to do retrospective and prospective studies of chimerism analysis by restriction fragment length polymorphism (RFLP) by Southern blotting and variable number of tandem repeats (VNTR) by polymerase chain reaction (PCR) to compare and contrast the methods. The retrospective group comprised 46 samples from 26 patients previously analyzed by RFLP, while the prospective group contained 34 samples from 25 patients. Using four different VNTR primers (D1S80, D17S30, D1S111, and APO-B), the recipient and donor samples amplified by the PCR were screened for unique banding patterns. The VNTR primer with the unique banding pattern was used to detect chimerism in each sample. A total of 635 VNTR analyses were performed. Interpretation was blinded for previous RFLP results. A comparison between the VNTR and RFLP results and a cost analysis of the two procedures were done. A unique VNTR banding pattern was present in 49 of 51 patients (identical twins in one case). The VNTR analysis showed complete chimerism in 68 samples, mixed chimerism in 9, and recurrences in 2. This agreed with the RFLP results in 64 (80%) of 80 samples. Failure to detect 1% to 10% of recipient DNA accounted for 15 (VNTR, 8; RFLP, 7) discordances. Follow-up revealed all donor DNA in five cases, decreasing quantities of recipient DNA in two cases (six samples), and no additional studies available in four cases. In one case, VNTR detected a complete chimerism when the DNA was insufficient for RFLP analysis. The cost analysis revealed an approximately 50% savings with the use of VNTR; VNTR is a viable alternative to RFLP in the detection of chimerism after bone marrow transplantation and offers substantial cost savings, faster turnaround time, easier preparation of the DNA, smaller DNA requirements, and the elimination of radioisotopes and cumbersome restriction enzymes.

Blotting, Southern↗

PubMed1997

Clinical aspects of juvenile rheumatoid arthritis.

This paper reviews studies in epidemiology, differential diagnosis, clinical manifestations, and treatment of juvenile rheumatoid arthritis (JRA) that have appeared during the past year. One epidemiologic study suggested a decreased incidence recently; however, changes over time in the ethnic and racial characteristics of the patients studied may also have played a role. Findings from an Australian study suggested that some studies may underestimate the true incidence of JRA if visits of physicians are the only basis for the studies. Finally, a Canadian study of incidence showed no seasonal correlations--except for the Prairie region--raising the possibility that the disease varies by region because of environmental factors or variations in ethnic background. Differential diagnostic issues were covered in several reports. One study suggested that elevations in lactate dehydrogenase levels identified children with malignancies who presented with musculoskeletal symptoms. Another study of children with Lyme disease failed to find any patients with asymmetric joint involvement, in contrast to JRA patients. Two studies from Europe reached opposite conclusions regarding whether the incidence of celiac disease was increased in JRA patients. Clinical studies included a French study showing increased production of interleukin-6 and interleukin-1-Ra during fever spikes in children with systemic JRA. An Italian study explored the potential role of interleukin-6 in the anemia of JRA patients. An American study confirmed decreases in markers of bone formation in JRA patients. Two treatment studies addressed the use of intravenous gamma globulin in JRA. Another report described two JRA patients who developed nodules while receiving methotrexate. Finally, a report added confirmation to the successful use of cyclosporine for macrophage activation syndrome in JRA.

Antirheumatic Agents↗