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Biomedical subjects

M D Miller

Publications and source records attributed to M D Miller.

At least 55 records · Page 3Linked to original sources
PubMed1999

A critical site in the core of the CCR5 chemokine receptor required for binding and infectivity of human immunodeficiency virus type 1.

Like the CCR5 chemokine receptors of humans and rhesus macaques, the very homologous (approximately 98-99% identical) CCR5 of African green monkeys (AGMs) avidly binds beta-chemokines and functions as a coreceptor for simian immunodeficiency viruses. However, AGM CCR5 is a weak coreceptor for tested macrophage-tropic (R5) isolates of human immunodeficiency virus type 1 (HIV-1). Correspondingly, gp120 envelope glycoproteins derived from R5 isolates of HIV-1 bind poorly to AGM CCR5. We focused on a unique extracellular amino acid substitution at the juncture of transmembrane helix 4 (TM4) and extracellular loop 2 (ECL2) (Arg for Gly at amino acid 163 (G163R)) as the likely source of the weak R5 gp120 binding and HIV-1 coreceptor properties of AGM CCR5. Accordingly, a G163R mutant of human CCR5 was severely attenuated in its ability to bind R5 gp120s and to mediate infection by R5 HIV-1 isolates. Conversely, the R163G mutant of AGM CCR5 was substantially strengthened as a coreceptor for HIV-1 and had improved R5 gp120 binding affinity relative to the wild-type AGM CCR5. These substitutions at amino acid position 163 had no effect on chemokine binding or signal transduction, suggesting the absence of structural alterations. The 2D7 monoclonal antibody has been reported to bind to ECL2 and to block HIV-1 binding and infection. Whereas 2D7 antibody binding to CCR5 was unaffected by the G163R mutation, it was prevented by a conservative ECL2 substitution (K171R), shared between rhesus and AGM CCR5s. Thus, it appears that the 2D7 antibody binds to an epitope that includes Lys-171 and may block HIV-1 infection mediated by CCR5 by occluding an HIV-1-binding site in the vicinity of Gly-163. In summary, our results identify a site for gp120 interaction that is critical for R5 isolates of HIV-1 in the central core of human CCR5, and we propose that this site collaborates with a previously identified region in the CCR5 amino terminus to enable gp120 binding and HIV-1 infections.

Amino Acid Sequence↗
PubMed1999

Nortriptyline and interpersonal psychotherapy as maintenance therapies for recurrent major depression: a randomized controlled trial in patients older than 59 years.

CONTEXT: Elderly patients with major depression are at high risk for recurrence, increased mortality, and chronic disability. OBJECTIVE: To determine the efficacy of maintenance nortriptyline hydrochloride and interpersonal psychotherapy (IPT) in preventing recurrence of major depressive episodes in patients older than 59 years. DESIGN: A 2 x 2 randomized, double-blind, placebo-controlled clinical trial, stratified by therapist. SETTING: University-based psychiatric research clinic. PATIENTS: Of a total of 187 patients with recurrent nonpsychotic unipolar major depression (average age, 67 years; one third aged > or =70 years) recruited through clinical referral and media announcements, 107 were fully recovered after open acute and treatment continuation with nortriptyline and IPT. These patients were randomly assigned to 1 of 4 maintenance therapy conditions. INTERVENTIONS: Monthly medication clinic with nortriptyline hydrochloride (80-120 ng/mL steady-state levels) (n = 24); medication clinic with placebo (n = 29); monthly maintenance IPT with placebo (n = 21); and monthly maintenance IPT with nortriptyline (n = 22). MAIN OUTCOME MEASURE: Recurrence of major depressive episode. RESULTS: The time to recurrence of a major depressive episode for all 3 active treatments was significantly better than for placebo. Recurrence rates over 3 years were as follows: nortriptyline and IPT, 20% (95% confidence interval [CI], 4%-36%); nortriptyline and medication clinic visits, 43 % (95% CI, 25%-61%); IPT and placebo, 64% (95% CI, 45%-83%); and placebo and medication clinic visits, 90% (95% CI, 79%-100%). Combined treatment with nortriptyline and IPT was superior to IPT and placebo and showed a trend to superior efficacy over nortriptyline monotherapy (Wald chi2 = 3.56; P = .06). Subjects aged 70 years and older had a higher and more rapid rate of recurrence than those aged 60 to 69 years. CONCLUSION: In geriatric patients with recurrent major depression, maintenance treatment with nortriptyline or IPT is superior to placebo in preventing or delaying recurrence. Combined treatment using both appears to be the optimal clinical strategy in preserving recovery.

Adrenergic Uptake Inhibitors↗
PubMed1999

Options in meniscal repair.

Meniscal repair is an important technique for the orthopaedic surgeon. As familiarity, equipment, and techniques improve, the interest in expanding the indications for application of meniscal repair also increases toward improving patient outcomes and long-term function. An overview of the indications, techniques, complications, and future direction of meniscal repair is presented in this article.

Arthroscopes↗
PubMed1999

Posterior cruciate ligament injuries.

Treatment of posterior cruciate ligament (PCL) injuries has received renewed attention over the past few years. This article reviews the anatomy, natural history, and pathophysiology of posterior cruciate ligament injuries. Also described are the physical examination and proper imaging modalities used to diagnose the injury. Appropriate operative and nonoperative management methods are discussed.

Arthroscopy↗
PubMed1999

"Cigar Wrap" technique for gracilis augmentation in hamstring anterior cruciate ligament reconstruction.

The use of Hamstring grafts for anterior cruciate ligament reconstruction is becoming increasingly popular. Most surgeons use a four-stranded graft consisting of double-stranded semitendinosus and gracilis tendons. The gracilis tendon, in addition to being smaller in diameter, is often shorter and more diminutive at its muscular end. We developed a technique for supplementing this tendon using excess semitendinosus tendon. This allows enhanced tibial tunnel fit and improved graft fixation.

Anterior Cruciate Ligament↗
PubMed1999

Human immunodeficiency virus type 1 expressing the lamivudine-associated M184V mutation in reverse transcriptase shows increased susceptibility to adefovir and decreased replication capability in vitro.

In a phase II study of 6-12 months of adefovir dipivoxil treatment in human immunodeficiency virus (HIV)-infected patients, HIV from 8 of 29 patients developed mutations in reverse transcriptase (RT) potentially attributable to adefovir dipivoxil therapy. Recombinant HIV from pre- and posttreatment plasma samples from these 8 patients showed no change or minor decreases in adefovir susceptibility, consistent with the durable antiviral effect observed. Additionally, HIV from 8 patients developed the M184V RT mutation because of concomitant lamivudine use. Recombinant HIV pairs from all 4 patients with zidovudine-resistant HIV showed statistically significant increases in adefovir susceptibility of 3- to 4-fold (to near wild type IC50), and HIV pairs from 2 of 4 patients with zidovudine-sensitive HIV showed a 2- to 3-fold increase in susceptibility. In growth kinetics studies, expression of the M184V RT mutation resulted in attenuated viral growth in peripheral blood mononuclear cell cultures. These studies suggest that patients possessing HIV with zidovudine and lamivudine resistance mutations may benefit from adefovir dipivoxil therapy.

Adenine↗
PubMed1999

The art of clinical management in pharmacologic trials with depressed elderly patients: lessons from the Pittsburgh Study of Maintenance Therapies in Late-Life Depression.

The authors outline the clinical management methods used in a long-term study of depressed elderly patients and comment on the positive aspects of such interventions on the successful recruitment and retention of subjects. Psychosocial or clinical management (CM) is the "glue" that holds a successful drug trial together. CM is recognized to be an essential element for success in drug trials for geriatric depression. The authors also discuss potentially negative aspects of comprehensive CM, such as those obscuring a psychotherapeutic effect in comparative studies.

Aged↗
PubMed1999

Treatment of bereavement-related major depressive episodes in later life: a controlled study of acute and continuation treatment with nortriptyline and interpersonal psychotherapy.

OBJECTIVE: The authors tested the hypothesis that nortriptyline and interpersonal psychotherapy, alone and in combination, are superior to placebo in achieving remission of bereavement-related major depressive episodes. METHOD: Eighty subjects, aged 50 years and older, with major depressive episodes that began within 6 months before or 12 months after the loss of a spouse or significant other were randomly assigned to a 16-week doubleblind trial of one of four treatment conditions: nortriptyline plus interpersonal psychotherapy (N = 16), nortriptyline alone in a medication clinic (N = 25), placebo plus interpersonal psychotherapy (N = 17), or placebo alone in a medication clinic (N = 22). The protocol required that the acute-phase double-blind treatment be ended after 8 weeks if Hamilton depression scale ratings had not improved by 50%. Remission was defined as a 17-item Hamilton scale score of 7 or lower for 3 consecutive weeks. RESULTS: The rate of remission for nortriptyline plus interpersonal psychotherapy was 69% (N = 11); for medication clinic, nortriptyline, 56% (N = 14); for placebo plus interpersonal psychotherapy, 29% (N = 5); and for medication clinic, placebo, 45% (N = 10). In a generalized logit model, there was a significant effect of nortriptyline over placebo but no interpersonal psychotherapy effect and no nortriptyline-by-interpersonal psychotherapy interaction. Rates of all-cause attrition were lowest in the nortriptyline plus interpersonal psychotherapy group. CONCLUSIONS: Nortriptyline was superior to placebo in achieving remission of bereavement-related major depressive episodes. The combination of medication and psychotherapy was associated with the highest rate of treatment completion. These results support the use of pharmacologic treatment of major depressive episodes in the wake of a serious life stressor such as bereavement.

Aged↗
PubMed1999

Three-year outcomes of maintenance nortriptyline treatment in late-life depression: a study of two fixed plasma levels.

OBJECTIVE: This study compared the long-term efficacy of two fixed plasma levels of nortriptyline in preventing or delaying recurrence of major depression in elderly patients and in minimizing residual depressive symptoms and somatic complaints. METHOD: The authors randomly assigned 41 elderly patients with histories of recurrent major depression to 3-year, double-blind maintenance pharmacotherapy using nortriptyline, with controlled plasma concentrations of 80-120 ng/ml versus 40-60 ng/ml. The authors compared times to, and rates of, recurrence of major depression. They also compared frequencies of side effects, noncompliance episodes, and subsyndromal symptomatic flare-ups. RESULTS: Major depressive episodes recurred for six (29%) of 21 subjects in the 80-120-ng/ml condition and eight (40%) of 20 subjects in the 40-60-ng/ml condition, a nonsignificant difference. Most recurrences took place in the first year of maintenance treatment. Hamilton depression scores in the subsyndromal range (higher than either 10 or 7) occurred significantly more often at 40-60 ng/ml, while constipation occurred significantly more often at 80-120 ng/ml. The proportions of patients reporting missed doses did not differ. CONCLUSIONS: Maintenance pharmacotherapy with nortriptyline at 80-120 ng/ml is associated with fewer residual depressive symptoms, that is, a less variable long-term response, than pharmacotherapy at 40-60 ng/ml, but constipation is more frequent and there is no difference in recurrence of syndromal major depressive episodes. Treatment at 80-120 ng/ml may be preferable, because of fewer residual symptoms and less variability of response, as long as side effect burden can be managed successfully.

Aged↗
PubMed1999

Accelerating antidepressant response in geriatric depression: a post hoc comparison of combined sleep deprivation and paroxetine versus monotherapy with paroxetine, nortriptyline, or placebo.

Speed of response is an important clinical issue in the treatment of depressed elderly patients. Our objective was to compare rapid response rates in a study combining therapeutic sleep deprivation (TSD) with paroxetine with two earlier randomized, double-blind studies in late-life depression, one of paroxetine versus nortriptyline and another of nortriptyline versus placebo. We measured depressive symptoms with the 17-item Hamilton Rating Scale of Depression (HRSD), defining rapid response as an HRSD < or = 10 by 2 weeks. With combination therapy (TSD + paroxetine), 9 of 13 patients (69%) experienced a rapid response. In the nortriptyline versus paroxetine study, nortriptyline brought about rapid response in 12 of 37 (32%) and paroxetine in 11 of 43 patients (26%). In the third study, rapid response to nortriptyline occurred in 10 of 41 patients (24%) and to placebo in 6 of 39 patients (15%). The overall chi square, including the rate of rapid response to placebo, was 14.87 (P = .005). The chi square on the four active treatment groups, excluding placebo, was 10.28 (P = .016). This preliminary observation suggests that combined therapy with TSD plus paroxetine may be twice as successful at achieving rapid response in elderly depressed patients than conventional monotherapy with medication or placebo. A prospective, placebo-controlled evaluation of this dual therapy is warranted.

Aged↗
PubMed1999

In vitro selection and characterization of HIV-1 with reduced susceptibility to PMPA.

9-(2-phosphonomethoxypropyl)adenine (PMPA) has demonstrated remarkable anti-simian immunodeficiency virus (SIV) activity in macaque models of SIV infection and transmission prevention. Recently, PMPA and its oral prodrug, bis-POC PMPA, have also shown potent anti-human immunodeficiency virus type 1 (HIV-1) activity in Phase I clinical studies. In vitro experiments were performed to address the resistance properties of PMPA. After eight passages in increasing concentrations of PMPA, HIV-1IIIB was able to grow in the presence of 2 microM PMPA, fivefold above the IC50 of PMPA for wild-type parental virus. Sequence analysis of the reverse transcriptase (RT) genes from four of 15 RT clones demonstrated the presence of a K65R substitution in RT and recombinant HIV expressing the K65R RT mutation showed a threefold to fourfold increase in IC50 value for PMPA as compared to wild-type. Additional experiments demonstrated that viruses expressing other nucleoside-associated RT resistance mutations all showed wild-type or < threefold reduced susceptibility to PMPA in vitro. Interestingly, lamivudine-resistant viruses expressing the M184V RT mutation showed wild-type to slightly increased susceptibility to PMPA in vitro and addition of the M184V mutation to HIV with the K65R mutation resulted in reversion to wild-type susceptibility for PMPA. In agreement with the cell culture findings, Escherichia coli-expressed K65R RT showed fivefold reduced susceptibility to PMPA diphosphate, the active moiety of PMPA. Furthermore, in combination experiments, PMPA with hydroxyurea showed synergistic inhibition of HIV replication in vitro. The potent antiretroviral activity and favourable resistance profile of PMPA and bis-POC PMPA are being further investigated in ongoing clinical trials.

Adenine↗
PubMed1999

Meniscal reconstruction. Part I: indications, techniques, and graft considerations.

Menisci are specialized structures capable of bearing loads, absorbing shock, stabilizing, and lubricating the knee joint. Increased knowledge of meniscal anatomy and function, as well as studies of chronic anterior cruciate ligament-deficient and -reconstructed knees, have indicated that loss of meniscal function is associated with progression of degenerative changes within the knee. Meniscal reconstruction has been developed to preserve those functions prior to the development of significant degenerative changes in patients who have undergone meniscectomy. Indications are still being defined. Meniscal reconstruction has been achieved by either arthroscopically assisted or open techniques. Anatomic placement and secure fixation of the graft are requirements to allow the optimal revascularization needed for successful incorporation of the graft. Part I of this review will discuss the anatomy and function of the meniscus, followed by the indications, techniques, and graft considerations for meniscal allograft reconstruction. In Part II, which will be published in the May 1999 issue, we will review the results, potential complications, and future directions of meniscal allograft reconstruction.

Anterior Cruciate Ligament↗
PubMed1999

Meniscal reconstruction. Part II: Outcome, potential complications, and future directions.

Currently, magnetic resonance imaging and second-look arthroscopy are the only methods available to objectively evaluate the outcome of meniscal reconstruction. While clinical studies indicate progressively improving outcomes of meniscal reconstruction, longer follow-up is needed to determine whether the natural history of joint degeneration can be altered. Part I of this comprehensive review, published in the April 1999 issue, discussed the anatomy and function of the meniscus, followed by the indications, techniques, and graft considerations for meniscal allograft reconstruction. Part II reviews the results, potential complications, and future directions of meniscal allograft reconstruction.

Animals↗
PubMed1999

A double-blind randomized comparison of nortriptyline and paroxetine in the treatment of late-life depression: 6-week outcome.

BACKGROUND: Some studies have suggested that selective serotonin reuptake inhibitors may be less efficacious than tricyclic antidepressants in the treatment of severe depression in older patients. The objective of this study was to compare the 6-week outcome of treatment with nortriptyline and paroxetine in older patients with a major depressive episode. METHOD: A double-blind randomized comparison of nortriptyline and paroxetine was conducted in 80 elderly (mean +/- SD age = 75.0 +/- 7.4 years) psychiatric inpatients and outpatients who presented with a major depressive episode. Dropout and response rates were compared in patients who began or completed treatment. Rates of response of inpatients and patients with melancholic depression were also compared. RESULTS: Over 6 weeks, there were no significant differences in dropout rates due to side effects (nortriptyline, 14% vs. paroxetine, 19%) or for any reason (27% vs. 33%). Similarly, there were no significant differences between the rates of favorable response to nortriptyline or paroxetine (intent-to-treat analysis, 57% vs. 44%; completer analysis, 78% vs. 66%). Analyses restricted to inpatients or to patients with melancholic depression yielded similar results. CONCLUSION: Nortriptyline and paroxetine appear to have similar efficacy and tolerability in the acute (6-week) treatment of older depressed patients, including hospitalized patients and those with melancholic features.

Age Factors↗