Prevalence and significance of acquired immunodeficiency syndrome-related retinal microvasculopathy

We performed ophthalmologic examinations on 127 subjects with or at risk for human immunodeficiency virus (HIV) infection over a one-year period to determine the prevalence and significance of retinal cotton-wool spots and hemorrhages (AIDS-related retinal microvasculopathy). Of 26 asymptomatic homosexual men, of whom 13 were HIV seronegative and 13 were HIV seropositive, none manifested this retinopathy. Three of 34 patients (9%) with AIDS-related complex and 29 of 67 patients (43%) with AIDS manifested retinopathy on the initial examination. This difference in the prevalence of retinopathy between groups was statistically significant (P less than .05). Patients with AIDS demonstrated 7.2 times greater odds of manifesting retinopathy than patients with AIDS-related complex (P less than .05). Within the group of patients with AIDS, the T helper (CD4) to suppressor (CD8) cell ratio was significantly associated with retinopathy at the initial ocular examination. The CD4:CD8 ratio of the total group of AIDS and AIDS-related complex patients with retinopathy was significantly lower than that of patients without retinopathy (P less than .05). There was no significant association between retinopathy and any specific past or concurrent opportunistic infection or neoplasm. The presence of retinopathy was not associated with symptoms in any patient. The lesions of AIDS-related retinal microvasculopathy may be an important finding in the evaluation of patients suspected to have HIV-related disease.

High-pressure liquid chromatographic analysis of eflornithine in serum

Eflornithine [2-(difluoromethyl)-DL-ornithine monohydrochloride, monohydrate; DFMO] is an ornithine decarboxylase inhibitor used to treat Pneumocystis carinii pneumonia (PCP) in AIDS patients unresponsive or intolerant to conventional drug therapy. A reversed-phase HPLC method utilizing precolumn dansylation is described which permits the analysis of DFMO in serum of AIDS patients in support of pharmacokinetic studies. Norvaline (2-amino valeric acid) was added as the internal standard and the sample was extracted with three portions of ice-cold 80% ethanol. The supernatants were evaporated in a vacuum oven at 50 degrees C, and the residue was dissolved in base and derivatized at 25 degrees C for 4 h in the dark using dansyl chloride in acetone. Dilute base was then added and 25 to 50 microL was injected into the HPLC. Chromatography was performed on a C-8, 15-cm column with a linear gradient from a 95:5 solution of 10 mM pH 4 acetate buffer and THF, to a 90:10 solution of acetonitrile and THF over a period of 28 min. Detection was by UV at 330 nm, and DFMO and norvaline eluted at 14.7 and 17.7 min, respectively. The method was linear over a range of 5 to 950 micrograms/mL, and replicate analyses of a 25-micrograms/mL control specimen produced a between-run coefficient of variation of 6%. No interferences were encountered in a variety of patient and normal serum blanks.

Defective megakaryocytopoiesis in the syndrome of thrombocytopenia with absent radii

The syndrome of thrombocytopenia with absent radii (TAR) is a hereditary condition whose pathogenesis is poorly understood. In this investigation we evaluated a female infant with TAR and her parents using in vitro haematopoietic colony forming assays and an antiserum against platelet membrane glycoproteins (PGP) to label smears of her bone marrow. Megakaryocyte colony growth in vitro was virtually absent in optimally stimulated cultures of the patient's bone marrow progenitors. In contrast, erythroid and myeloid colony growth from the TAR infant's marrow cells was preserved. Staining of the patient's bone marrow smears with PGP antiserum detected no immature, small megakaryocyte precursors. A high level of megakaryocyte colony stimulating activity was detected in serum from the TAR infant, activity comparable to that present in sera from adults with aplastic anaemia. The elevated serum activity decreased by 6 months of age at which time partial platelet recovery had occurred. Evaluation of both peripheral blood haematopoietic progenitor cells and sera from the TAR infant's parents demonstrated no significant abnormalities. We conclude that the principle haematopoietic defect in this patient with TAR syndrome is the absence or arrested development of the committed megakaryocyte progenitor cell. Humoral regulation of megakaryocytopoiesis appears intact and is responsive to the degree of megakaryocytic hypoplasia.

Recombinant gibbon interleukin-3 stimulates megakaryocyte colony growth in vitro from human peripheral blood progenitor cells

Gibbon interleukin-3 (rIL-3) has recently been cloned and found to have a high degree of homology with the human IL-3 molecule. In this investigation, we evaluated the effects of gibbon rIL-3 on normal human peripheral blood megakaryocyte progenitor cell growth in vitro. Gibbon rIL-3 exhibited substantial megakaryocyte colony stimulatory activity (Meg-CSA), supporting peak colony numbers at a concentration of 1 U/ml. Megakaryocyte colony growth induced by rIL-3 reached 58% of the maximum achieved with the active, Meg-CSA-containing protein fraction of aplastic canine serum. Increasing gibbon rIL-3 concentrations also stimulated a 4-5-fold increase in megakaryocyte colony size and resulted in a decrease in geometric mean megakaryocyte ploidy. Ploidy values fell from 8.5N +/- 1.4 (+/- SEM) at an rIL-3 concentration of 0.1 U/ml to a minimum of 2.9N +/- 0.3 at 10 U/ml. In the presence of rIL-3 at 1.0 U/ml, megakaryocyte colony growth was linear with cell plating density and the regression line passed approximately through the origin. The effects of rIL-3 on megakaryocyte colony growth were independent of the presence of T-lymphocytes in the cultures. Cross-species evaluation of murine and gibbon IL-3 indicated that its bioactivity is species restricted. Murine IL-3 did not support colony growth from human megakaryocyte progenitors and gibbon rIL-3 showed no activity in stimulating acetylcholinesterase production by murine bone marrow cells. Gibbon rIL-3 is a potent stimulator of the early events of human megakaryocyte progenitor cell development promoting predominantly mitosis and early megakaryocytic differentiation.

Anastomotic false aneurysms of the abdominal aorta and the iliac arteries

Anastomotic false aneurysm (AFA) of the aorta or iliac artery is a potentially lethal complication of prosthetic grafts. To study this complication, the records of 18 patients with 22 noninfected AFAs (15 aortic and seven iliac) were reviewed. Patients with an intact AFA had a pulsatile abdominal mass, abdominal pain, an occluded graft, peripheral emboli, or a femoral anastomotic false aneurysm. All patients with a ruptured AFA were in shock, but 67% (four of six) had symptoms before hemorrhage. For diagnosis, single-plane angiography was 69% accurate (11 of 16), computed tomography was 100% accurate (six of six), and ultrasound was used once and suggested an AFA. Three patients with an AFA less than 5 cm diameter were initially observed; however, all three aneurysms rapidly enlarged and one ruptured. The operative mortality rate was 8% (1 of 12) for patients with an intact aneurysm and 67% (four of six) for patients with a ruptured aneurysm. Treatment was resection of the AFA and replacement with a new graft. Retroperitoneal AFAs often appear years after the initial operation, and life-long follow-up is required for patients with an aortic or iliac graft. All retroperitoneal AFAs should be resected since the outcome of patients with a ruptured AFA is poor.

The action of gamma-aminobutyric acid on the horizontal cells of the skate retina

The effects of gamma-aminobutyric acid (GABA) were studied in the superfused retina of the skate. Intracellular recordings were made from horizontal cells. After application of 500 microM GABA there was a depolarization of the membrane potential, a decrease in the light-evoked amplitude of the response and an increase in the duration of the waveform.

Growth characteristics of circulating hematopoietic progenitor cells from patients with essential thrombocythemia

Peripheral blood mononuclear cells from five patients with essential thrombocythemia (ET) were cultured in vitro to evaluate restricted megakaryocytic (CFU-Meg), myeloid (CFU-GM), and erythroid (BFU-E) progenitor cell development. Varying concentrations of aplastic canine serum served as the source of megakaryocyte colony-stimulating activity, and cultured megakaryocyte ploidy distributions were determined by Feulgen staining and microfluorometry. Megakaryocyte colony growth was strikingly abnormal in all five patients evaluated. Four of the 5 had a marked expansion in the concentration of circulating CFU-Meg and 3 of 4 manifested abnormalities in cultured megakaryocyte colony size (2 unusually large and 1 small). Unstimulated megakaryocyte colony growth was substantially increased in three patients. However, the fraction of megakaryocyte progenitors in cell cycle was near or below normal in all instances. Endomitotic megakaryocyte development was disordered in each of the four ET patients in whom it was evaluable. In normal subjects, mean megakaryocyte ploidy values vary biphasically with aplastic canine serum concentration and peak at 13.2 N following 12 to 15 days of culture. In contrast, day 12 mean ploidy values in cultures from the ET patients remained low at all aplastic canine serum concentrations and reached a maximum averaging only 8.4 N. Three patients were evaluated serially at extended culture durations of up to 21 days. The cultured megakaryocyte ploidy was unchanged during this interval for two of the patients. For the third patient, ploidy increased steadily, reaching abnormally high ploidy values by day 21. Progenitor cell expansion was limited to the megakaryocyte line in three patients. However, two patients had substantial increases in CFU-GM, one of whom also had a marked increase in BFU-E. There was no significant unstimulated colony growth by either CFU-GM or BFU-E. These data indicate that ET is usually characterized by an expansion in the concentration of circulating CFU-Meg in vivo which manifest both disordered replication and endoreduplication in vitro.

Intraoperative colonoscopy

From 1973 to 1985, we performed intraoperative colonoscopy on 68 patients with indications as follows: location of a previous polypectomy site (44%), inability to complete colonoscopy preoperatively (24%), locating nonpalpable polyps (13%), to define the source of lower gastrointestinal bleeding (4%), and to perform polypectomy (3%). Endoscopic evaluation influenced the outcome in 93% of the patients. There were two complications, both splenic capsular tears. Despite our increased ability to resolve several of the earlier indications for intraoperative colonoscopy by examination prior to celiotomy, there remains a significant role for intraoperative colonoscopy.

Evaluation of bone marrow megakaryocyte ploidy distributions in persons with normal and abnormal platelet counts

Using bone marrow smears of the type prepared routinely in clinical practice, we determined megakaryocyte ploidy distributions in five normal persons, eight patients with both normal platelet counts and normal bone marrow morphology, and 18 patients with quantitative platelet disorders. To include 2N and 4N megakaryocytes in the ploidy distribution histograms, all megakaryocytes were identified by serial immunologic labelling with rabbit antiserum to human platelet glycoproteins and rhodamine-conjugated goat anti-rabbit igG. Cell nuclei were concurrently Feulgen stained with bis-aminophenyl-oxdiazole, and the nuclear fluorescent signals were quantified photometrically. A modal megakaryocyte ploidy value of 32N was seen in 10 of the 13 persons with normal platelet counts, and geometric mean megakaryocyte ploidy values averaged 24.9N +/- 7.0N (arithmetic mean +/- SD). In these normal control individuals, 2N and 4N megakaryocytes accounted for 11.1% of all megakaryocytes, and 2.6% of the megakaryocytes were 128N. Shifts to a higher mean ploidy were observed in five of seven patients with idiopathic thrombocytopenic purpura, resulting from increased percentages of 64N and 128N megakaryocytes at the expense of 4N, 8N, and 16N cells. Shifts to lower ploidy were demonstrated in two patients with acute myelogenous leukemia and one patient each with thrombotic thrombocytopenic purpura and isoimmune thrombocytopenia. Four of five patients with essential thrombocythemia had strikingly abnormal megakaryocyte ploidy histograms characterized by the presence of unusually high ploidy 256N and 512N megakaryocytes. These 256N and 512N cells were virtually unique to the patients with essential thrombocythemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Examination of the correlation of serum metoclopramide levels with antiemetic efficacy in patients receiving cisplatin

The existence of a threshold serum metoclopramide level above which total protection from cisplatin-induced vomiting is more likely to occur has been proposed. We monitored serum metoclopramide levels prior to the third metoclopramide dose in the first cisplatin treatment cycle in patients receiving metoclopramide 2 mg/kg x 4 as part of a randomized double-blind cross-over study comparing single-agent metoclopramide with combination metoclopramide and dexamethasone. Serum samples from 35 patients (17 receiving single-agent metoclopramide and 18 receiving the combination) were analyzed using reverse-phase high-pressure liquid chromatography (HPLC). A wide variation in metoclopramide levels was observed (range 273-3380 ng/ml). Serum levels obtained from the same patient on multiple treatment cycles were well correlated, and the addition of dexamethasone did not alter serum metoclopramide levels. No threshold level could be identified for the two groups (single-agent or combination antiemetic therapy) considered individually or considered together. However, significantly more vomiting episodes and a lower incidence of total protection were noted in patients with metoclopramide levels above 1469 ng/ml receiving metoclopramide alone. This effect was nullified in the combination antiemetic group. Our data do not support a directly proportional relationship between serum metoclopramide level and antiemetic protection. However, a non-linear relationship with a possible agonist/antagonist effect is suggested.

Modest stimulatory effect of recombinant human GM-CSF on colony growth from peripheral blood human megakaryocyte progenitor cells

Recombinant human granulocyte-macrophage colony-stimulating factor (rGM-CSF) has been previously demonstrated to stimulate colony formation from human myeloid, erythroid, and multipotential stem cells. In this investigation, we evaluated the effects of rGM-CSF on colony growth by human megakaryocyte progenitors (CFU-Meg). rGM-CSF was tested at concentrations of 0.1-100 U/ml in plasma clot cultures of adherent-depleted normal peripheral blood mononuclear cells. Control cultures were concurrently prepared containing either no stimulator or megakaryocyte colony-stimulating factor (Meg-CSF) partially purified from aplastic canine serum. rGM-CSF increased megakaryocyte colony numbers from a baseline of 4.3 +/- 1.4 (+/- SEM) in the unstimulated cultures to a maximum of 21.0 +/- 5.3 colonies at an rGM-CSF concentration of 1.0 U/ml. Corresponding megakaryocytic colony size increased from 4.4 to 8.3 cells/colony. Further increasing the rGM-CSF concentration resulted in decreasing megakaryocyte colony growth, reaching 6.8 +/- 2.9 colonies at 100 U/ml. The maximum number of megakaryocyte colonies stimulated by rGM-CSF was only 23.3% of that achieved in the control cultures containing optimal concentrations of serum-derived Meg-CSF protein (2.0 mg/ml). Megakaryocyte colonies stimulated by rGM-CSF consisted of predominantly low ploidy cells approximately equally distributed in 2N, 4N, and 8N ploidy classes. There was no increase in ploidy with any rGM-CSF concentration. These data indicate that rGM-CSF has modest activity in stimulating human megakaryocyte colony growth that is substantially less than that present in serum-derived Meg-CSF. rGM-CSF appears to primarily affect the early mitotic phase of megakaryocyte colony development with little influence on megakaryocyte endoreduplication.

Echocardiographic mitral valve prolapse in ballet dancers: a function of leanness

To determine the prevalence of mitral valve prolapse in ballet dancers by echocardiography and to establish which anthropometric measurements best predict the presence of mitral valve prolapse, we compared 44 professional dancers (22 men and 22 women) with 52 controls (24 men and 28 women). Forty-eight percent (21 of 44) of dancers had echocardiographic mitral valve prolapse compared with 10% (5 of 52) of controls (p less than 0.01). The dancers weighed less than the controls and had significantly smaller bony diameters and body circumferences. However, only ponderal index was predictive of mitral valve prolapse in both dancers and controls. Thus, echocardiographic mitral valve prolapse is associated with low body weight relative to height and neither to ballet dancing nor to a distinct body habitus. Echocardiographic mitral valve prolapse may represent a normal variant in the majority of asymptomatic, thin subjects without auscultatory findings.

Interrelationship between mitosis and endomitosis in cultures of human megakaryocyte progenitor cells

Sera from dogs rendered aplastic by total-body irradiation stimulate human bone marrow megakaryocyte progenitors to form megakaryocyte colonies in plasma clot cultures. In this investigation, we evaluated the effects of varying concentrations of such sera on both the mitotic and endomitotic phases of human megakaryocyte development in vitro. When low concentrations of aplastic canine sera (2.5% to 5.0% [vol/vol]) were added to cultures of human peripheral blood mononuclear cells in place of normal AB serum, megakaryocyte colony formation was augmented fivefold, cell numbers per colony increased approximately 2.5-fold, and the geometric mean megakaryocyte ploidy almost doubled. Further increasing the aplastic canine serum concentration from 10% to 30% (vol/vol) stimulated no additional colony formation. However, there was a further augmentation of cell numbers per colony associated with a progressive decrease in the mean megakaryocyte ploidy. Megakaryocyte cultures were harvested after 7, 12, 15, and 19 days of incubation, and these demonstrated that the lower mean ploidy values found at the higher concentrations of aplastic canine serum did not result from delayed endoreduplication. At all aplastic serum concentrations evaluated, there existed a strong correlation between nuclear ploidy and cell diameter. We conclude that both the mitotic and endomitotic events in human megakaryocytopoiesis may be influenced by a factor or factors present in aplastic canine serum. At lower in vitro concentrations, such sera stimulate both mitosis and endomitosis, which promotes the development of megakaryocyte colonies composed of larger cells with a higher mean ploidy. With increasing aplastic serum concentrations, colony formation plateaus and mitosis is favored over endomitosis. This results in colonies composed of more numerous but smaller megakaryocytes with a lower mean ploidy. Our data suggest that the size and extent of polyploidization that can be achieved by a developing megakaryocyte may be influenced by the mitotic prior history of its immediate precursor cell.

Pharmacokinetic changes in aging

A multitude of factors influence the prescribing, dosing, and clinical monitoring of long-term drug therapy in elderly patients. These include life-style and environment, possible multiple disease states and concomitant medications, compliance, and continuous changes in physiology, all of which can--with advancing age--gradually alter the pharmacodynamics and pharmacokinetics of drugs. The physiologic changes associated with aging that can affect the absorption, distribution, excretion, and metabolism of drugs are reviewed and related to the clinical use of several drugs that are widely used in elderly patients. Important clinical factors may also magnify or counteract the physiologic changes that occur with respect to altered drug response. Finally, the pharmacokinetic properties of the available oral hypoglycemic agents are described as they relate to selection of an optimal drug in elderly diabetic patients.

Evaluation of arthritis self-management courses led by laypersons and by professionals

We compared the relative effectiveness of 2 arthritis patient education interventions. One intervention was modeled after that developed by Lorig, whereas the other had similar content but used health professionals rather than laypersons as instructors. Both interventions resulted in an increase in patients' knowledge of arthritis and in their use of exercise compared with a control group that received no intervention. However, neither intervention was any more effective than nonintervention in lessening patients' pain, improving their functioning, enhancing social support systems, lessening their depression, or improving their health behaviors beyond that of exercise. No differences in outcome measures were found between groups led by professional instructors and those led by lay instructors.

Left ventricular hypertrophy in athletes: an exercise-echocardiographic study

Left ventricular dimensions measured by M-mode echocardiography of 10 distance runners and 10 wrestlers were compared to 10 sedentary controls at rest and during 12 min of semisupine, graded bicycle ergometer exercise. At rest, runners and wrestlers demonstrated greater left ventricular mass compared to controls (mean values, 311.8 and 325.9 vs 215.9 g, respectively: P less than 0.05). In wrestlers, this was due to increased left ventricular septal (13.5 mm) and posterior wall thickness (12.9 mm) compared to controls (9.1 and 10.1 mm, respectively: P less than 0.05). In runners, this was due to increased left ventricular end-diastolic dimension (55.8 mm) compared to controls (49.7 mm) (P less than 0.05). During exercise, the different patterns noted at rest among the three groups in left ventricular dimensions and function persisted and were preserved: runners maintained a higher end-diastolic dimension compared to wrestlers and controls and greater shortening dimension compared to wrestlers. Absolute changes in left ventricular parameters from rest to exercise were not significantly different among the three groups.

CONCLUSIONS

1) different patterns of left ventricular hypertrophy exist among different types of athletes, with mainly increased wall thickness in primarily statically trained athletes and increased volume in dynamically trained athletes; and 2) these differences observed at rest persist during moderate-intensity, semisupine ergometer exercise and have direct functional significance, thereby emphasizing the differences found in cardiac dimensions among different types of athletes.

Clinical pharmacokinetics of high-dose metoclopramide in cancer patients receiving cisplatin therapy

Using a sensitive and specific high-pressure liquid chromatographic (HPLC) assay, we measured serum levels of metoclopramide in 18 cancer patients receiving high-dose intravenous (IV) therapy to prevent cisplatin-induced emesis. Ten patients were treated with one or more courses with metoclopramide alone (1.0 to 3.0 mg/kg) in an open-label study, and eight patients were treated with a fixed 2.0 mg/kg dose of metoclopramide with or without adjunct dexamethasone (20 mg) using a randomized, crossover design. The pharmacokinetics of metoclopramide were determined, and the relationship between serum levels and clinical response was evaluated. The pharmacokinetic parameters of high-dose metoclopramide were found to be similar to those reported for standard promotility doses, and no dose dependency was demonstrated over the range of doses studied. No clear correlation between serum metoclopramide levels and prevention of cisplatin-induced emesis was observed. The addition of dexamethasone resulted in clinical improvement in two of eight patients, but had no effect on serum metoclopramide levels or kinetic parameters. Results in this study population do not show metoclopramide levels to be related to antiemetic effect following IV cisplatin therapy.

Lethal atherosclerosis associated with abnormal plasma and tissue sterol composition in sitosterolemia with xanthomatosis

Tissue sterol composition was determined in an 18-year-old male with sitosterolemia with xanthomatosis who died suddenly and whose coronary and aortic vessels showed extensive atherosclerosis and, for comparison, in an 18-year-old male with minimal atherosclerosis who died accidently. Sterols in the control tissues (plasma, erythrocytes, cardiac muscle, lung, liver, aorta, and brain) contained cholesterol with only trace amounts of cholestanol. In contrast, sterols in corresponding tissues of the sitosterolemic subject (except brain) were composed of cholesterol, increased amounts of plant sterols, campesterol and sitosterol, and 5 alpha-saturated stanols, cholestanol, 5 alpha-campestanol, and 5 alpha-sitostanol, that were deposited in approximately the same ratio as present in plasma. However, sitosterolemic brain sterol composition resembled that of the control brain with cholesterol and only trace amounts (less than 1%) of cholestanol and phytosterols. The sitosterolemic aorta was extensively atherosclerotic and contained more than twice the quantity of sterols as the control aorta (5.6 mg/g versus 2.6 mg/g) with increased amounts of cholesterol, plant sterols, and 5 alpha-saturated stanols. These results indicate that cholesterol, plant sterols, and 5 alpha-stanols are deposited prematurely and are associated with accelerated atherosclerosis in subjects with sitosterolemia with xanthomatosis.

Biochemical and immunocytological localization of molluscan small cardioactive peptides in the nervous system of Aplysia californica

High pressure liquid chromatography (HPLC) followed by bioassay on isolated snail hearts were used to locate two related peptides, termed small cardioactive peptides A and B (SCPA and SCPB) in each of the central ganglia of Aplysia. The peptides are most concentrated in the buccal ganglia, the ganglia involved in the control of feeding movements. Immunocytology with antisera raised to conjugated SCPB stained three groups of neurons in the buccal ganglia. One group consisted of relatively small neurons that were tightly clustered. The second group was comprised of larger neurons that were more scattered. The third group was made up of several neurons including the two largest in the ganglia, identified cells B1 and B2. B1 and B2 and other neurons in this group innervate the gut by way of the esophageal nerve. HPLC-bioassay of single, individually dissected B1 or B2 neurons demonstrated that the two peptides are present in a single cell. For B2, but not B1, choline injected into the cell body was converted to the conventional transmitter, acetylcholine. This indicates that, in addition to the two peptides, B2 also contains choline acetyltransferase, and raises the possibility that acetylcholine and the SCPs may act as co-transmitters in B2. Strong immunocytological staining of fibers and varicosities was observed in the neuropilar region of the cerebral, pleural, pedal, and abdominal ganglia. In addition to the buccal ganglia, immunoreactive neurons were observed in all of the other central ganglia. The high concentration of the SCPs and the relatively large number of immunoreactive neurons in the buccal ganglion suggest a particularly important role of these peptides specifically in feeding behavior. However, the widespread occurrence of the SCPs in fibers and neuronal cell bodies throughout the nervous system suggests that these peptides also may have additional behavioral functions in Aplysia.