Retroviral vector-mediated gene transfer into human hematopoietic progenitor cells

The transfer of the human gene for hypoxanthine phosphoribosyltransferase (HPRT) into human bone marrow cells was accomplished by use of a retroviral vector. The cells were infected in vitro with a replication-incompetent murine retroviral vector that carried and expressed a mutant HPRT complementary DNA. The infected cells were superinfected with a helper virus and maintained in long-term culture. The production of progeny HPRT virus by the bone marrow cells was demonstrated with a colony formation assay on cultured HPRT-deficient, ouabain-resistant murine fibroblasts. Hematopoietic progenitor cells able to form colonies of granulocytes or macrophages (or both) in semisolid medium in the presence of colony stimulating factor were present in the nonadherent cell population. Colony forming units cloned in agar and subsequently cultured in liquid medium produced progeny HPRT virus, indicating infection of this class of hematopoietic progenitor cell.

Improvements in dehydration and cement line staining for methacrylate embedded human bone biopsies

Undemineralized methacrylate embedded bone biopsies and other bone specimens can be processed much more rapidly by application of acidified 2,2-dimethoxypropane (DMP) dehydration, which requires two hours, than by traditional graded ethanol dehydration, which requires at least four days. This shortened processing time is valuable when biopsy results are urgently needed to detect osteomalacia or to determine bone features prior to possible parathyroidectomy. We have processed over 200 bone specimens with DMP and have compared DMP dehydration to graded ethanol dehydration in 11 biopsies in which two plugs were available from the same patient. DMP dehydration does not compromise the following: tetracycline retention, Goldner's stain, acid phosphatase localization or histochemical identification of aluminum. Cement lines, which provide a record of past remodelling, are useful in clinical interpretation of bone biopsies. We have adapted two stains, toluidine blue and methylene blue/basic fuchsin, for improved cement line identification. Five-micrometer sections individually demineralized in acetate buffer prior to cement line staining show best results with toluidine blue at pH 5.5 and with methylene blue/basic fuchsin at pH 2.5-3.5.

Glial cells metabolically cooperate: a potential requirement for gene replacement therapy

Immunofluorescently labeled glial cells are shown by radioautography to metabolically cooperate with hypoxanthine phosphoribosyltransferase-deficient fibroblasts. The observations of cooperation without cell contact and of incorporation gradients around the glial cells suggest that cooperation occurs through extracellular transport of radiolabeled purine compounds. The transfer of radiolabeled adenine, adenosine, or methylthioadeninosine is supported by the quantitative loss of cooperation when the recipient cell is also deficient in enzymes required for adenine or adenosine salvage. The demonstration of glial cell cooperation provides impetus for current research toward gene replacement therapy for the neurologic symptoms of the Lesch-Nyhan syndrome.

Alterations of inosinate branchpoint enzymes in cultured human lymphoblasts

The specific activities of the three enzymes of the inosinate branchpoint are independently regulated when lymphoblasts are grown under various tissue culture conditions. In comparison to rapidly dividing cells, lymphoblasts at high cell density with no cellular division have decreased activity of the enzymes which commit inosinate to adenylate or guanylate, while cytoplasmic 5'-nucleotidase is relatively preserved. A linear relationship between inosinate dehydrogenase activity and growth rate (r = 0.92) exists in lymphoblasts with slowed growth rates. In contrast, in dividing cells adenylosuccinate synthetase and 5'-nucleotidase do not vary with growth rate. Adenylosuccinate synthetase and inosinate dehydrogenase activities appear to be related to the presence or rate of cellular division, as opposed to the presence or degree of neoplastic transformation. Lymphoblast lines with alterations of specific purine metabolic enzymes have characteristic alteration of the inosinate utilizing enzymes. Deficiencies of purine nucleoside phosphorylase or hypoxanthine phosphoribosyltransferase, abnormalities which render the cell unable to salvage purine effectively, are associated with depressed inosinate dehydrogenase activity. Insertion of the hypoxanthine phosphoribosyltransferase gene into hypoxanthine phosphoribosyltransferase-deficient cells normalizes inosinate dehydrogenase activity, while a hypoxanthine phosphoribosyltransferase-deficient mutant selected from a hypoxanthine phosphoribosyltransferase-containing line has depressed inosinate dehydrogenase activity. In contrast, overactivity of phosphoribosylpyrophosphate synthetase, with enhanced excretion of purines due to excessive production, is associated with elevated inosinate dehydrogenase activity. Inosinate dehydrogenase appears to be regulated according to the availability of purine nucleotides. Patients who overproduce uric acid and potentially have undescribed purine metabolic defects are now being screened for abnormalities in the inosinate branchpoint enzymes.

Mouth and genital ulcers with inflamed cartilage: MAGIC syndrome. Five patients with features of relapsing polychondritis and Behçet's disease

Five patients with features of coexistent relapsing polychondritis and Behçet's disease are described. Review of the literature supports the overlap of the clinical manifestations of these two conditions. A common immunologic abnormality is likely, and elastin is cited as a possible target antigen. The "mouth and genital ulcers with inflamed cartilage (MAGIC) syndrome" is the proposed name for this entity.

Adenosine release from stimulated mast cells

Adenosine release has been documented in lung tissue exposed to hypoxic conditions or antigen challenge. Exogenous adenosine potentiates mediator release from stimulated rat serosal and mouse bone marrow-derived mast cells. To investigate the production and release of adenosine from stimulated mast cells, rat serosal mast cells were purified on metrizamide gradients, sensitized with anti-dinitrophenol IgE for 30 min at 37 degrees C, and challenged in the presence of 1 microM deoxycoformycin with either dinitrophenol-conjugated bovine serum albumin antigen, the calcium ionophore A23187, or compound 48/80. Reactions were terminated by centrifugation, and the supernatants and pellets were assayed for adenosine and ATP content, respectively, by high performance liquid chromatography. The adenosine concentration of the supernatants increased from 0.036 +/- 0.003 nmol per 10(6) cells to 0.049, 0.056, and 0.129 nmol per 10(6) cells 60 sec after challenge with antigen, 48/80, or A23187, respectively. After ionophore stimulation, increased extracellular adenosine was evident by 15 sec, peaked by 60 sec, and remained constant for at least 5 min. A significant decline in stimulated ATP levels was observed within 30 sec, suggesting that the enhanced adenosine concentrations may result from the breakdown of ATP. Cultured mouse bone marrow-derived mast cells under similar conditions also displayed augmented extracellular adenosine levels with A23187 challenge. This endogenous source of adenosine may act locally through a positive feedback mechanism to potentiate immediate hypersensitivity reactions.

Long-term calcitonin therapy in postmenopausal osteoporosis

Results are presented from a 2-year controlled study evaluating the efficacy of 100 units synthetic salmon calcitonin/d in the treatment of postmenopausal osteoporosis. All patients received 400 units D2 po qd and 1200 mg CaCO3 po qd. The 21 control and 24 treated patients (mean age 65) were not statistically different at baseline. Although mean total body calcium (TBCa) was not significantly different between treated and control patients throughout the study, mean differences in the change in TBCa from baseline (treated minus control) were significant at 12, 18, and 26 months. The mean slope of TBCa for treated patients, but not for controls, was significantly positive through 18 months. Iliac crest bone biopsies showed (1) a significantly greater percent total bone area in treated compared to control patients at 2 years, and (2) a significantly decreased percent resorbing surface in treated patients when evaluated by paired difference from baseline. At 4 months, serum calcium values were significantly lower in treated patients than in controls (mean difference, treated minus controls), but were not statistically different from controls at study completion. Urine calcium increased significantly for the first 4 months in treated subjects and then declined to baseline levels. Since urinary calcium increased, the increase in TBCa was probably associated with an increase in net intestinal calcium absorption.

Osteoporosis associated with pregnancy and lactation: bone biopsy and skeletal features in three patients

Case reports of three young patients who developed vertebral fractures and skeletal complications during pregnancy and/or lactation are presented. Radiologic features are described. All three had severe disease with three to nine vertebral fractures at presentation postpartum. In two patients, follow-up for 5-7.8 yr (including further pregnancy in each) revealed no further fractures. In general, serum and urine features were normal, the exceptions being a low serum 25-hydroxyvitamin D level (plus intermittent elevation of serum parathyroid hormone) in one, a tendency to low plasma alkaline phosphatase in another, and in the third (the most severely affected patient) a transient rise in urinary hydroxyproline and plasma alkaline phosphatase during a phase of bone loss following her second and third pregnancies. Bone biopsies performed 1 to 6-1/2 yr after parturition showed quantitative bone histologic features and bone formation rates that, as a group, were not significantly different from either normal or postmenopausal osteoporotic subjects. These patients did not have osteomalacia and did not show high turnover osteoporotic features. It is possible that this type of osteoporosis may be somewhat self-limiting, although this hypothesis is subject to great influence by any adaptive lifestyle changes introduced by the patient. The severe fracture history of these patients emphasizes the gravity of their bone disease and stresses the need for further study on the etiology and treatment of this form of osteoporosis.

Stanozolol in postmenopausal osteoporosis: therapeutic efficacy and possible mechanisms of action

To assess the efficacy of the anabolic steroid stanozolol in the treatment of osteoporosis, a 29-month double-blind study was performed with 23 treated and 23 control postmenopausal osteoporotic women. Drug efficacy was assessed by serial determinations of total body calcium (TBC--total bone mass) by neutron activation analysis, regional bone mass (RBM) by single-photon absorptiometry, and by spinal roentgenograms. Total body calcium increased 4.4% from baseline values (P less than 0.01) in the treated group and remained unchanged in the control group; the difference in the change in TBC between the treated and control groups was significant (P less than 0.03). The effect of the drug on TBC persisted throughout the 29-month period. In contrast to TBC, measurements of RBM indicated no significant differences between the treated and placebo groups, suggesting a possible differential response to therapy at various skeletal sites. No new spinal compression fractures were noted in the treated group (compared with three new fractures in the control group). Assessment of serum and urine values indicated a decrease in the level of urinary calcium and an increase in the level of total urinary cyclic AMP in the treated group. These changes were observed even though the level of serum iPTH was significantly decreased during the study. An analysis of changes in bone biopsy specimens revealed no significant differences between the treated and control groups. Seventy-six percent of the treated subjects developed SGOT elevations or other side effects from the stanozolol therapy; at no time were these effects sufficiently severe to cause termination of medication. The data suggest that long-term use of stanozolol increases the net total bone mass above pretreatment levels.

Aortic thrombosis during sigmoidoscopy in Behçet's syndrome

A patient with Behçet's syndrome suffered acute paraparesis during sigmoidoscopy. An aortogram demonstrated thrombosis of the distal abdominal aorta just above the bifurcation; thrombectomy resulted in complete return of neurologic function. Examination of the clot disclosed a preponderance of polymorphonuclear granulocytes. We propose that mechanical trauma from this otherwise benign procedure caused the vascular lesion. Patients with a similar predisposition to arterial or venous thrombosis may, in unusual circumstances, be jeopardized by proctosigmoidoscopy.

Skeletal remodelling and bone related hormones in two adults with increased bone mass

This study of two cases documents increased bone mass in a 30-yr old man and osteopetrosis in a 38-yr-old woman and examines the patients in terms of radiologic features, bone photon absorptiometry and bone biopsy analyses which include tetracycline kinetics. Both patients had elevated bone mass based on quantitative bone histology of iliac crest biopsies normal, or low PTH, and normal calcitonin values. However, they differed markedly from each other in other respects: One patient possessed significantly increased rates of bone formation and mineralization, had elevated serum alkaline phosphatase, increased total hydroxyproline over a 24 hour urine collection but displayed a normal amount of bone surface involved in resorption. The other subject had normal bone formation parameters, but had elevated serum acid phosphatase and a significantly elevated resorbing (crenated) surface. Although most theories ascribe and cause of osteopetrosis to decreased resorption, our study shows that increased bone formation, even when accompanied by normal resorption, can lead to the abnormal accumulation of bone mass. In this respect, the resorptive response of this patient was abnormal; the normal coupled relationship between bone formation and bone resorption, which ensures proper control of endosteal bone volume, had been lost.

The diagnosis of osteoporosis

A rational approach to the diagnosis of osteoporosis by the primary care physician is outline, with emphasis on the patient who presents with chronic back pain and a vertebral compression fracture. The basic information includes data from the patient's history and physical examination, laboratory, x-ray and bone biopsy studies, and determination of bone mineral content (BMC) by photon absorptiometry. Characteristic radiologic features associated with bone loss, BMC changes, and bone biopsy findings are illustrated. This diagnostic approach, summarized in a flow diagram, poses a series of questions; the answer to each question leads either ot a diagnostic conclusion or to further questions which must be answered. This permits decision as to whether a compression fracture is due to trauma, local osteoporosis, osteomalacia, secondary osteoporosis or primary osteoporosis. In te study population (150 subjects), 80 percent of patients presenting with vertebral compression fractures had primary osteoporosis.

Alterations in islet cell ultrastructure following streptozotocin-induced diabetes in the rat

The response of islet cells to streptozotocin-induced diabetes was investigated by transmission electron microscopy. Rats were given streptozotocin i.p. (100 mg/kg followed by another dose of 25 mg/kg 24 h later) and sacrificed after 10 days. Pancreata from rats with high serum glucose values (381-553 mg/100 ml) were selected for ultrastructural examination. Islets in these animals were smaller and much less frequent than those of control animals. Cell types were not always easily identifiable in diabetic animals: distinction between A and B cells was often difficult. Cells of some islets displayed diminished electron density and less structured cytoplasm, yet nuclei were not pyknotic. Such cells were usually deficient in secretion granules. A cells were least affected. Cells in the centers of some islets possessed multivesicular bodies, prominent dilated Golgi cisternae and secretory granules which were often pleomorphic. Nuclear envelopes of some peripheral islet cells were swollen and distended; mitochondria were enlarged and the rough endoplasmic reticulum prominent. Some islet cells retained features of B cells in spite of marked ultrastructural alterations. This diversity of morphological findings contrasts with the homogeneity of the population of streptozotocin-diabetic rats with respect to metabolic responses.

Ultrastructural features of spironucleosis (hexamitiasis) in x-irradiated rat small intestine

An alteration in the host response to the intestinal protozoan Spironucleus (Hexamita) muris was noted in x-irradiated rat small intestine. When few were present in the crypt lumina, the intestinal microvillar border was normal. However, when larger numbers were present, the microvilli were greatly reduced in numbers or entirely absent in some regions. The organism was identified in the base of the crypt lumen, in apical portions of mucous cells, and near the basement membrane. Spironucleus enclosed by digestive vacuoles occasionally appeared to be in the process of being extruded through the basement membrane. Not all intracellular protozoa were surrounded by such digestive vacuoles. Spironucleus was never seen in association with the digestive vacuoles of Paneth cells. Since it has been suggested that Paneth cells have a role as a fixed phagocyte, ingesting protozoa and other microorganisms, the results presented here suggest that this function may have been impaired in irradiated animals.

Superoxide dismutase activity of normal murine liver, regenerating liver, and H6 hepatoma

By means of both direct assay and gel electrophoresis, normal A/J mouse liver was shown to possess both Cu-Zn and Mn superoxide dismutase (SD) activity. H6 hepatoma cells contained Cu-Zn SD activity, but no Mn SD activity was detectable. Isolated mitochondria from normal liver contained both forms of the enzyme, but isolated mitochondria from H6 hepatoma cells contained no SD activity. To ascertain whether this loss of Mn SD activity was characteristic of these tumor cells or was simply a property of rapidly dividing cells, SD activity was measured in regenerating liver. Mn SD activity was present in the regenerating liver at all times after surgery. Hence loss of the Mn SD activity seemed to be a characteristic of some tumor cells but not of corresponding rapidly dividing normal cells.