Puromycin aminonucleoside induces glomerular epithelial cell apoptosis

Glomerular epithelial cell (GEC) injury has been considered to play an important role in puromycin aminonucleoside (PAN)-induced nephrosis. We studied the effect of PAN on rat as well as human GEC apoptosis. Morphogic evaluation of GEC apoptosis and necrosis was carried out by staining with H-33342 and propidium iodide. GEC apoptosis was further confirmed by DNA fragmentation assay (by both agarose gel electrophoresis and end-labeling). To determine the dose- and time-response effect of PAN, GECs were treated with variable concentrations of PAN (10 to 500 microg/ml) for variable time periods (6 to 48 h). To determine the role of gene synthesis, we studied the effect of actinomycin D (a transcriptional inhibitor) on PAN-induced GEC apoptosis. To determine the role of free radicals, we evaluated the effect of superoxide dismutase (SOD), dimethylthiourea (DMTU), and catalase on PAN-induced GEC apoptosis. PAN induced GEC apoptosis in a dose- and time-dependent manner. PAN at a high concentration (PAN, 100 microg/ml) also induced a moderate degree of GEC necrosis. In DNA fragmentation assays PAN-treated GECs showed the classic ladder pattern. PAN-induced GEC apoptosis was partly attenuated with free radical scavengers, such as SOD, DMTU, and catalase. In addition, actinomycin D attenuated PAN-induced GEC apoptosis. PAN induces GEC apoptosis, which may be mediated through the generation of reactive oxygen species.

Transforming growth factor beta induces mesangial cell apoptosis through NO- and p53-dependent and -independent pathways

BACKGROUND

Because transforming growth factor beta (TGF-beta) has been shown to have a bimodal effect on mesangial cell (MC) proliferation, we studied its effect on MC apoptosis.

METHODS

Cultured mouse MCs were used to evaluate the effect of TGF-beta. Morphologic evaluation of MC apoptosis was performed by staining cells with H-33342 and propidium iodide. To confirm the effect of TGF-beta on MC apoptosis, DNA was extracted from control and TGF-beta-treated MCs and run on gel electrophoresis. We evaluated the effect of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, on TGF-beta-induced MC apoptosis to determine the role of NO and studied the effect of sodium nitroprusside (SNP) and SNAP (S-nitroso-N-acetyl-penicillamine) on MC apoptosis to confirm the effect of NO. We examined the role of p53 by studying the effect of TGF-beta on MCs derived from p53 knockout mice (p53KO-MC) as well as a normogenic strain (N-MC). We also examined the effect of TGF-beta, SNP, and SNAP on apoptosis of p53 mutant (MDAMB-231) and wild-type p53 (MCF-7) breast cancer cell lines. In addition, Western blots were generated from control, TGF-beta-treated, and SNAP-treated MCs and probed for the expression of p53.

RESULTS

TGF-beta promoted MC apoptosis. Moreover, TGF-beta-treated MCs displayed integer multiples of 180 base pairs (ladder pattern). L-NAME inhibited TGF-beta-induced MC apoptosis. Furthermore, SNP and SNAP, NO donors, promoted MC apoptosis. TGF-beta also enhanced the MC expression of p53. TGF-beta induced only a moderate degree of apoptosis in MCs derived from p53KO-MC when compared with N-MCs. Similarly, the TGF-beta-induced apoptosis of MDAMB-231 was of a moderate degree when compared with MCF-7 cells.

CONCLUSIONS

We hypothesize that TGF-beta promotes MC apoptosis through NO generation and p53-dependent and -independent pathways.

Reliability in grading the severity of lumbar spinal stenosis

Stenosis of the lumbar spinal canal is a major cause of disability and lost productivity. Computed tomography (CT) is used commonly to assess the presence and severity of spinal stensosis, because it is relatively inexpensive, readily available, and has few adverse effects. The ability of four surgeons to agree about the presence and severity of lumbar spinal stenosis based on plain CT scans was evaluated from 30 scans of varying stenosis severity (normal to severe). Kappa, a measure of chance-corrected agreement, was calculated. Surgeons exhibited moderate agreement for the presence or absence of spinal stenosis (kappa = 0.58+/-0.06). Agreement regarding the severity of stenosis, when present, was poor (kappa = 0.26+/-0.04). The ability of surgeons to agree was not improved when individual features of the CT scans were assessed (facet joint arthrosis, ligamentum flavum hypertrophy, disk protrusion, and nerve root impingement). This study suggests that CT scans are not a reliable method by which to examine the severity of lumbar spinal stenosis.

Morphine-induced macrophage apoptosis: the role of transforming growth factor-beta

Laboratory and clinical reports indicate that opiate addicts are prone to infections. This effect of opiates is partly attributed to opiate-induced macrophage (Mphi) apoptosis. In the present study, we evaluated the role of transforming growth factor-beta (TGF-beta) in morphine-induced apoptosis of murine J774 cells and peritoneal Mphi. Mphi harvested from morphine-treated mice showed greater (P < 0. 0001) apoptosis when compared with control Mphi. Morphine also enhanced apoptosis of J774 cells and peritoneal Mphi. Anti-TGF-beta antibody inhibited (P < 0.001) the morphine-induced apoptosis in J774 cells (control 0.7 +/- 0.4%; 10-6 M morphine 23.5 +/- 0.7%; anti-TGF-beta antibody (Ab) + 10-6 M morphine 8.1 +/- 0.7%; apoptotic cells/field) and peritoneal Mphi (control 1.5 +/- 0.9%; 10-6 M morphine 29.1 +/- 1.4%; 10-6 M morphine + anti-TGF-beta Ab 19. 1 +/- 1.8%; apoptotic cells/field). TGF-beta enhanced (P < 0.001) apoptosis of J774 cells and peritoneal Mphi. TGF-beta also promoted Mphi DNA fragmentation into integer multiples of 180 bp (ladder pattern). Immunocytochemical studies revealed that morphine enhanced the Mphi cytoplasmic content of TGF-beta. In addition, Western blotting showed increased production of TGF-beta by morphine-treated J774 cells when compared with control cells. Morphine increased J774 cell expression of bax. Interestingly, morphine-induced bax expression was inhibited by anti-TGF-beta Ab. As both morphine-induced J774 cell apoptosis and bax expression were inhibited by anti-TGF-beta Ab, it appears that morphine-induced J774 cell apoptosis may be mediated through the generation of TGF-beta.

Internal mammary artery perfusing Leriche's syndrome in association with significant coronary arteriosclerosis: four case reports and review of literature

Four cases of collateral perfusion of a lower extremity by way of an internal mammary artery in the presence of Leriche's syndrome are described. Angiographic documentation preceding coronary artery bypass grafting prevented an acutely ischemic leg in two of the cases.

Delayed presentation of spinal stab wound: case report and review of the literature

Stab wounds to the spinal cord are relatively uncommon in North America, but even rarer is the presentation of such an injury in a delayed fashion. We report a case of a 31-year-old male who presented with neurologic deficit 4 weeks after a stab wound injury to the spine. Because of worsening neurologic deficit, the retained knife fragment was operatively removed, and the patient had an uneventful recovery. The management of such an injury is discussed, with a review of the literature.

Ethanol-induced neutrophil apoptosis is mediated through nitric oxide

Clinical reports indicate that acute ethanol intoxication in chronic ethanol abusers is associated with neutropenia. We hypothesize that ethanol accelerates the apoptosis of neutrophils thus decreasing the peripheral blood count of neutrophils. We studied the effect of ethanol on neutrophil apoptosis in vivo as well as in vitro. Human neutrophils harvested from healthy subjects after an alcohol drinking binge showed enhanced apoptosis (before, 0.5+/-0.25 vs. after, 26.1+/-2.6% apoptotic neutrophils/field). Peritoneal neutrophils isolated from ethanol-treated rats also showed increased (P < 0.0001) apoptosis when compared with neutrophils isolated from control rats (control, 0.8+/-0.2% vs. ethanol, 11.8+/-0.7% apoptotic neutrophils/field). In in vitro studies, ethanol in concentrations of 50 mM and higher accelerated the apoptosis of human and rat neutrophils. This effect of ethanol on human neutrophils was time dependent. DNA isolated from ethanol-treated human neutrophils displayed integer multiples of 180 base pairs (ladder pattern), further confirming the effect of ethanol on neutrophil apoptosis. N(G)-monomethyl-L-arginine monoacetate and N(G)-nitro-L-arginine methyl ester, inhibitors of nitric oxide (NO) synthase, attenuated the ethanol-induced neutrophil apoptosis. Sodium nitroprusside, a NO donor, also promoted neutrophil apoptosis. Moreover, ethanol enhanced neutrophil expression of inducible NO synthase. In addition, ethanol stimulated neutrophil NO generation. These results suggest that ethanol accelerates neutrophil apoptosis. This effect of ethanol on neutrophil apoptosis seems to be mediated through the generation of NO.

HIV-1 gp120 envelope protein modulates proliferation of human glomerular epithelial cells

Glomerular epithelial cells (GEC) have been demonstrated to undergo morphological alterations in human immunodeficiency virus (HIV)-associated focal glomerulosclerosis. In the present study, we evaluated the effect of HIV-1 gp120 envelope protein on the growth of cultured human (H) GEC. gp120 protein enhanced (P < 0.001) the proliferation of HGEC at lower concentrations. The mitogenic effect of gp120 protein on HGEC was further confirmed by enhanced accumulation of proliferating nuclear cell antigen (PCNA) by gp120 protein-treated cells, as compared with control cells. On the contrary, gp120 protein at higher concentrations suppressed (P < 0. 001) the growth of HGEC. To evaluate the mechanism of gp120 protein-induced HGEC growth suppression, we examined the effect of gp120 protein on HGEC apoptosis. gp120 protein at higher concentrations promoted the apoptosis of HGEC. At higher concentrations, gp120 protein also enhanced DNA fragmentation of HGEC. Anti-gp120 antibody attenuated the proliferative as well as the apoptotic effects of gp120 protein on HGEC. Because protein kinase C as well as tyrosine kinase inhibitors partially inhibited gp120-induced proliferation, gp120 appears to be activating both the protein kinase C and tyrosine kinase pathways. In addition, gp120 protein at lower concentrations enhanced mRNA expression of c-fos and at higher concentrations promoted mRNA expression of c-jun. We conclude that gp120 has a bimodal effect on proliferation of HGEC. This effect may be mediated through the activation of early growth genes.

Morphine promotes apoptosis in Jurkat cells

Patients with intravenous heroin addiction are prone to recurrent infections and at times these infections are fatal. We evaluated the effect of morphine on the apoptosis of Jurkat cells and freshly isolated human T lymphocytes. Morphine promoted apoptosis of both the Jurkat cells and the freshly isolated T lymphocytes in a dose-dependent manner. DAGO, a specific mu receptor agonist, also promoted Jurkat cell apoptosis. DNA isolated from morphine-treated Jurkat cells and T lymphocytes also showed integer multiples of 200 base pairs. Superoxide dismutase (SOD) enhanced lymphocyte apoptosis; whereas catalase attenuated the morphine-induced apoptosis of Jurkat cells as well as of T lymphocytes. Morphine-treated Jurkat cells also showed a decreased expression of bcl-2 and an enhanced expression of bax. In addition, morphine-treated Jurkat cells showed activation of caspase-3. These results indicate that morphine-induced T lymphocyte apoptosis may be mediated through the generation of reactive oxygen species. The change in ratio of bax and bcl-2 seems to tilt the balance toward apoptosis, leading to the activation of caspase-3. This study provides further support for the hypothesis that morphine may be directly compromising immune function by enhancing apoptosis of T lymphocytes in patients with heroin addiction.

Escherichia coli promotes macrophage apoptosis

BACKGROUND

Escherichia coli is the bacterium most commonly isolated from the urine of patients with urinary tract infection (UTI). Recurrent episodes of UTI lead to renal interstitial scarring. In interstitial fibrosis and scarring, infiltration of mononuclear cells has been reported to play a key role.

MATERIALS AND METHODS

We evaluated the effect of two strains of E. coli--the pathogenic BH-5 and the plasmidless, nonfimbriated HB-101-on human monocyte and murine macrophage apoptosis.

RESULTS

E. coli BH-5 enhanced apoptosis in a time- and dose-dependent manner. It also promoted necrosis in a time- and dose-dependent manner. Strain HB-101 promoted monocyte apoptosis in a dose-dependent manner. However, the magnitude of HB-101-induced monocyte apoptosis was lower than BH-5-induced macrophage apoptosis.

CONCLUSION

The ability of E. coli to induce apoptosis may contribute to its virulence and play a role in renal interstitial scarring.

Predictors of return to work after anterior cervical discectomy

Return to previous level of employment after surgery is important to patients. Predictors of return to work have been well described in lumbar disc surgery. However, this information cannot be generalized to the population undergoing cervical discectomy. The authors retrospectively reviewed 67 consecutive patients who underwent anterior cervical discectomy. Strict inclusion criteria were used. Baseline demographics were recorded as well as other potential predictors of postoperative return to work such as number of levels of disease, smoking history, and disability claims. Follow-up information about work status was reviewed with each patient at office visit. Forty-five patients were found eligible for the study. At a mean follow-up of 2.8 years (SD 1.4), 38% had not returned to work by 1 year. Preoperative sick leave in this group was significantly greater than for those patients who returned to work within the year (p = 0.0014). Postoperative neck pain was more common in individuals who did not return to work after surgery (p = 0.01). Increasing age and disability claims also appeared to negatively impact the ability to return to work. Gender, type of work, smoking history, and number of levels of disc disease did not appear to have any association with postoperative return to work. The authors conclude that the duration preoperative sick leave and postoperative neck pain negatively impact postoperative work status in patients undergoing anterior cervical discectomy. Age and disability claims also influence return to work.

Ethanol-induced macrophage apoptosis: the role of TGF-beta

Both clinical and laboratory reports indicate that ethanol addicts are prone to recurrent infections. We hypothesize that ethanol promotes macrophage apoptosis, thus compromising the efficiency of the mononuclear phagocyte system in dealing with infection. We studied the effect of ethanol on macrophage apoptosis. Human monocytes isolated from healthy subjects after an alcohol drinking binge showed enhanced apoptosis (before, 1.2 +/- 0.3% vs after, 28.4 +/- 3.7% apoptotic cells/field). Peritoneal macrophages harvested from ethanol-treated rats also showed increased (p < 0.0001) apoptosis. DNA isolated from peritoneal macrophages of ethanol-treated rats displayed integer multiples of 200 base pairs (ladder pattern). Furthermore, macrophages harvested from ethanol-treated rats had an enhanced expression as well as accumulation of TGF-beta. In in vitro studies, ethanol promoted apoptosis of human monocytes as well as rat peritoneal macrophages. In addition, ethanol enhanced apoptosis of murine macrophages (J774) in a time-dependent manner. The ethanol-induced apoptosis was amplified by LPS and partly attenuated (p < 0.001) by anti-TGF-beta Ab. TGF-beta also promoted macrophage apoptosis in a dose-dependent manner. Moreover, ethanol enhanced TGF-beta protein production by macrophages. These results indicate that ethanol promotes macrophage apoptosis. This effect of ethanol seems to be partly mediated through the generation of TGF-beta by macrophages.

Pathogenesis of neuroborreliosis--lessons from a monkey model

The diagnosis of human LNB can be difficult, because its major clinical manifestations--meningitis, facial palsy, radiculitis, and neuritis--are non-specific and the characteristic skin lesion is usually absent at the time of neurological involvement. Thus, CSF assays are often used in diagnosis. Culture of CSF is rarely performed because it has a low yield and requires special culture medium. PCR of the CSF identified spirochetal DNA in clinical specimens with greater sensitivity, but it suffers from a number of disadvantages. Measurement of specific antibody in the CSF also has its limitations. The role of available assays for LNB has not been studied carefully in a comparative investigation. The recent development of the nonhumane primate (NHP) model of LNB allows us to address this need in a faithful model of human LNB. We compared PCR and culture in their ability to detect spirochetal presence in the CSF and brain tissue of infected NHPs, and related these measures of infection to the development of anti-B. burgdorferi antibody. We also tested a bioassay, the mouse infectivity test (MIT), in this model. Using these four assays (PCR, culture, MIT, and CSF Ab) at least one assay for spirochetal presence in CSFs from NHPs was positive in 87% of CSFs tested during early infection in the CNS. Detection of spirochetal presence by PCR, MIT, and culture in the CSF was inversely related to the concomitant presence of anti-B. burgdorferi antibody intrathecally. The performance of any particular test was associated with the strength of the host immune response. In early CNS infection, when anti-B. burgdorferi antibody had not yet appeared, or in immunocompromised hosts, the MIT compared favorably to culture and PCR in infected NHPs; antibody in the CSF was the most useful assay in immunocompetent NHPs. This is the first study demonstrating that a bioassay using inoculation of mice, the mouse infectivity test (MIT), has potential as a useful adjunct in the diagnosis of LNB. The MIT for LNB was modeled after the rabbit infectivity test or RIT, which is considered the "gold standard" for the diagnosis of the related CNS infection, neurosyphilis, and felt to be very sensitive and specific. The presence of specific anti-B. burgdorferi antibody in the CSF is the most widely used assay for Lyme neuroborreliosis. In the immunocompetent NHPs in our study it was a very successful assay for detection of CNS invasion. However, it is frequently false-negative, especially early in the course of the infection, or if there is transient immunosuppression. Transient suppression of the anti-B. burgdorferi immune response in the human could occur in instances of co-infection, i.e. simultaneous transmission via the tick of another pathogen other than B. burgdorferi. Thus, mild immunosuppression as accomplished in our NHPs with corticosteroids was designed to mimic conditions in the human host which allow B. burgdorferi in the natural state to gain a firm foothold in the central nervous system in the 10-15% of B. burgdorferi-infected patients who develop clinically symptomatic nervous system disease. This study is the first to compare utility of available diagnostic techniques in LNB in which necropsy proved presence of infection in the CNS. None of the assays was ideal for all conditions, and the utility of the assay was associated with the host immune status. The differences in the responses of immunocompromised and immunocompetent NHPs in this study were striking. In immunocompetent NHPs the window of opportunity for CNS invasion prior to the development of CSF antibody was brief, and the chance of detection of spirochete low by any of the three techniques used (i.e. culture, PCR, or MIT); in this group, measurement of CSF antibody was generally diagnostic. In immunocompromised NHPs, intrathecal antibody production was delayed, and this helpful diagnostic assay was false-negative; diagnosis required more labor-intensive assays such as PCR, culture, an

A prospective comparison of clinical examination, MRI, bone SPECT, and arthroscopy to detect meniscal tears

Recent studies have shown that SPECT bone scintigraphy is valuable to detect meniscal tears of the knee. This has not been formally assessed in a prospective study, and no substantive study has compared bone SPECT with other noninvasive diagnostic methods. One hundred consecutive patients referred to an orthopedic surgeon with undiagnosed knee pain were assessed by clinical examination, MRI, SPECT bone scintigraphy, and arthroscopy. The MRI and SPECT bone scan findings were reported blinded to other information. Using arthroscopy as a gold standard, both MRI and SPECT showed high diagnostic ability to detect meniscal tears, with respective sensitivity rate, specificity rates, and positive and negative predictive accuracies of 80%, 71%, 84%, and 71% for MRI and 84%, 80%, 88%, and 76% for SPECT. Some meniscal tears were detected by MRI alone (n = 5) or SPECT alone (n = 8). SPECT bone scintigraphy is a suitable alternative to MRI to detect meniscal tears. The comparable diagnostic ability of SPECT bone scintigraphy implies that it can be used successfully when MRI is unavailable or unsuitable.

Matrix-mesangial cell interaction modulates migration of macrophages

BACKGROUND

Macrophages (Møs) have been demonstrated to play an important role in immune-mediated renal injury. Accumulation of macrophages in the mesangium has been reported to be a key event in the development of focal glomerulosclerosis. We hypothesized that mesangial cells (MCs) and matrix interaction may be a determinant for the migration of Møs into the mesangium. Therefore, we studied the effect of the interaction between matrix and MCs on the migration of Møs.

METHODS

Mouse MCs were plated on Petri dishes coated either with buffer, collagen type I, III, IV, or Matrigel in media containing 1% fetal calf serum for 48 hours. Subsequently, supernatants were collected and stored. The effect of these supernatants (conditioned media) was evaluated on the migration of Møs across a filter in a modified Boyden chamber.

RESULTS

Conditioned media from MCs grown on Matrigel (MC-Matrigel interaction products, MC-MGP) enhanced the migration of macrophages across a filter in a modified Boyden chamber when compared with conditioned media from MCs grown on plastic, collagen type I, type III, or type IV (MC-PP, MC-CI, MC-CIII, and MC-CIV). MC-MGP enhanced the migration of Møs in a dose dependent manner. Anti-MCP-1 antibodies attenuated (P < 0.05) the MC-MGP-induced Mø migration (MC-MGP, 16.8 +/- 2.5 vs MC-MGP + anti-MCP-1 antibody, 6.5 +/- 1.2 migrated macrophages/field, n = 12). Anti-TGF-beta antibodies did not attenuate MC-MGP-induced Mø migration. MCs grown on Matrigel showed a 5-fold increase of MCP-1 mRNA when compared with cells grown on plastic or collagen type IV.

CONCLUSIONS

The present study suggests that matrix components may modulate the migration of Møs. This effect of MC-matrix interaction on macrophage migration may be mediated through the generation of MCP-1.

HIV-1 gp120 envelope protein and morphine-tubular cell interaction products modulate kidney fibroblast proliferation

BACKGROUND

Renal interstitial scarring is an important feature of HIV-associated nephropathy. Intravenous drug abuse has been demonstrated to be a risk factor for the development of HIV-associated nephropathy in patients with HIV infection. We studied the effect of tubular cell-morphine and/or HIV-1 gp120 envelope protein interaction products on kidney fibroblast (KF) proliferation and apoptosis.

METHODS

Tubular cell-morphine and/or gp120 interaction products were prepared by incubating confluent human proximal tubular cells with buffer (TCP), morphine (10(-3) mol/L) (TCM-IP), gp120 (0.01 microgram/mL)(TC-120IP), or morphine (10(-3) mol/L) + gpl20 (0.01 microgram/mL) (TCM-120IP). To evaluate the effect of tubular cell interaction products (TCIP) on KF proliferation, growth arrested kidney fibroblasts were treated with variable concentrations (5%, 10%, 20%, 30%, and 50%) of TCP, TCM-IP, TC-120IP, or TCM-120IP for 48 hours. To evaluate the role of cytokines in TCIP-induced KF proliferation, cells were incubated with TCIP with or without cytokine neutralizing antibodies to TGF-beta, TNF-alpha, FGF, or IL-6 for 48 hours. Subsequently, cells were counted in a hemocytometer (n = 3). To evaluate the effect of TCIP on KF apoptosis, cells were treated with 50% TCP, 50% TCM-IP, 50% TC-120IP, or 50% TCM-120IP for 24 hours and stained with H-33342 and propidium iodide. In parallel experiments KFs were harvested under identical conditions, DNA was isolated and run on gel electrophoresis. To evaluate the role of early growth genes in TCM-120-induced KF proliferation, TCM-120IP-treated cells were probed with cDNA for c-fos and c-jun.

RESULTS

TC-120IP at a lower concentration (20%) enhanced (P < 0.001) proliferation of KF when compared with TCP. TCM-IP did not stimulate KF proliferation. On the contrary, TCM-120IP at a lower concentration (20%) promoted (P < 0.001) KF proliferation when compared with TCP, TCM-IP and TC-120IP. TCM-120IP at a lower concentration (20%) also enhanced KF mRNA expression of c-fos and c-jun. TCM-120IP enhanced KF proliferation in a dose-dependent manner. All tubular cell interaction products at a higher concentration (50%) promoted apoptosis of KF.

CONCLUSIONS

Tubular cell-gp120 interaction products stimulated KF proliferation. Morphine amplified the effect of tubular cell-gp120 interaction on the proliferation of KF. TCM-120IP-induced KF proliferation may be mediated through the expression of early growth genes; whereas TCM-120IP-induced KF growth suppression may be mediated through the induction of apoptosis.

Maturational change in the cortical response to hypoperfusion injury in the fetal sheep

A characteristic of perinatal encephalopathies are the distinct patterns of neuronal and glial cell loss. Cerebral hypoperfusion is thought to be a major cause of these lesions. Gestational age is likely to influence outcome. This study compares the cortical electrophysiologic and histopathologic responses to hypoperfusion injury between preterm and near term fetuses. Chronically instrumented 0.65 (93-99-d, n = 9) and 0.9 (119-133-d, n = 6) gestation fetal sheep underwent 30 min of cerebral hypoperfusion injury. The parasagittal cortical EEG and impedance (measure of cytotoxic edema) responses plus histologic outcome (3 d) were compared. The acute rise in impedance was similar in amplitude, but the onset was delayed (5.0 +/- 0.7 versus 9.1 +/- 1.1 min, p < 0.05) in the preterm fetuses relative to those near term. In contrast the extent of the secondary rise was reduced (p < 0.01) and peaked earlier in the preterm fetuses (19.8 +/- 1.0 versus 40.5 +/- 3.5 h, p < 0.01). Both groups had a similar fall in EEG spectral edge frequency. The preterm fetuses had a milder loss of EEG intensity at 72 h (-7.7 +/- 1.5 versus -12.8 +/- 0.9 dB, p < 0.05). At both ages there was a predominantly parasagittal cortical distribution of damage with a similar pattern of neuronal loss in the thalamus and striatum. There was extensive selective neuronal loss within the upper layers of the cortex in those near term. In contrast the preterm fetuses developed subcortical infarcts (p < 0.05). The cortical response to injury altered during the last trimester. The results suggest the severity of the delayed phase of cortical neuronal injury and selective neuronal loss increased near term. In contrast, the preterm fetuses had a more rapidly evolving injury leading to necrosis of the subcortical white matter.

Morphine enhances macrophage apoptosis

Laboratory data indicate that morphine decreases the numbier of peritoneal and alveolar macrophages (Mphi) and compromises their phagocytic capability for immune complexes and bacteria. We hypothesize that morphine decreases the number of, as well as compromises the phagocytic capability of, Mphi by programming their death. We studied the effect of morphine on Mphi apoptosis in vivo as well as in vitro. Peritoneal Mphi harvested from morphine-treated rats showed DNA fragmentation. Morphine enhanced murine Mphi (J 774.16) apoptosis in a dose-dependent manner. Human monocytes treated with morphine showed a classic ladder pattern in gel electrophoretic and end-labeling studies. Morphine promoted nitric oxide (NO) production both under basal and LPS-activated states. N(G)-nitro-L-arginine methyl ester (L-NAME) and N(G)-monomethyl-L-arginine monoacetate (L-NMMA), inhibitors of NO synthase, attenuated the morphine-induced generation of NO by Mphi. Morphine also enhanced Mphi mRNA expression of inducible NO synthase (iNOS). Since morphine-induced Mphi apoptosis was inhibited by L-NAME and L-NMMA, it appears that morphine-induced Mphi apoptosis may be mediated through the generation of NO. Morphine promoted the synthesis of Bax and p53 proteins by Mphi. Moreover, IL-converting enzyme (ICE)-1 inhibitor attenuated morphine-induced Mphi apoptosis. These studies suggest that morphine activates the induction phase of the apoptotic pathway through accumulation of p53. The effector phase of morphine-induced apoptosis appears to proceed through the accumulation of Bax and activation of ICE-1. The present study provides a basis for a hypothesis that morphine may be directly compromising immune function by promoting Mphi apoptosis in patients with opiate addiction.

Simulated glomerular hypertension promotes mesangial cell apoptosis and expression of cathepsin-B and SGP-2

BACKGROUND

Focal glomerulosclerosis (FGS) is characterized by the accumulation of mesangial matrix and lack of mesangial cells (MC). We studied the role of glomerular hypertension (GH) in the development of MC hypoplasia.

METHODS

We used an in vitro model of GH to study the effect of GH on MC apoptosis. Cultured rat endothelial cells were grown in the intracapillary space and MCs were grown in the extracapillary space. MC proliferation as well as apoptosis was evaluated under simulated normal glomerular pressure (SNGP) as well as simulated glomerular hypertension (SGH). Apoptosis was determined morphologically by DNA fragmentation using Hoechst staining as well as with the use of DNA gel electrophoresis. MCs grown under SNGP and SGH were also evaluated for the expression of genes associated with active cell death. In addition, we evaluated the effect of direct applied pressure on MC apoptosis.

RESULTS

MCs grown under SGH were less elliptical and had a tendency to develop a dome in the center. Direct applied pressure promoted MC apoptosis in a dose and time dependent manner. DNA gel electrophoresis from MCs grown under SGH also showed integer multiples of 180 base pairs (ladder pattern); whereas cells grown under SNGP showed no DNA fragmentation. SGH increased mRNA expression of cathepsin-B (SNGP, 0.31 +/- 0.04 vs SGH, 0.57 +/- 0.03, P < 0.01, n = 3) and SGP-2 (SNGP, 0.55 +/- 0.05 vs SHG, 1.08 +/- 0.12, P < 0.01, n = 3) in MCs when compared to cells grown under SNGP.

CONCLUSIONS

The present in vitro study suggests that GH has the potential to convert a hypercellular mesangium into a hypocellular one. This effect of GH is associated with expression of genes associated with active cell death.

Morphine modulates proliferation of kidney fibroblasts

Renal interstitial scarring is an important component of heroin-associated nephropathy. Kidney fibroblasts have been demonstrated to play a role in the development of renal scarring in a variety of renal diseases. We studied the effect of morphine, an active metabolite of heroin, on the proliferation of kidney fibroblasts. Morphine at a concentration of 10(-12) M enhanced (P < 0.001) the proliferation of kidney fibroblasts (control, 67.5 +/- 2.0 vs. morphine, 112.2 +/- 10.1 x 10(4) cells/well). [3H]thymidine incorporation studies further confirmed these results. Morphine at concentrations of 10(-12) M to 10(-10) M also modulated mRNA expression of early growth related genes (c-fos, c-jun and c-myc). Morphine at concentrations of 10(-8) to 10(-4) M promoted apoptosis of kidney fibroblasts and also enhanced the synthesis of p53 by kidney fibroblasts. We speculate that morphine-induced kidney fibroblast proliferation may be mediated through the activation of early growth related genes, whereas morphine induced kidney fibroblast apoptosis may be mediated through the generation of p53. The present in vitro study provides a hypothetical basis for the role of morphine in the development of renal interstitial scarring in patients with heroin-associated nephropathy.

Morphine induces splenocyte apoptosis and enhanced mRNA expression of cathepsin-B

Morphine has been demonstrated to modulate immune function. We studied whether morphine modulates apoptosis of splenocytes. Splenocytes were isolated from control and morphine treated rats. Splenocytes isolated from morphine treated rats showed increased percentage (P < 0.001) of apoptosis when compared to splenocytes isolated from untreated rats (control, 4.7 +/- 1.0% apoptotic splenocytes/field vs. morphine, 47.8 +/- 3.4% apoptotic splenocytes/field). These results were further confirmed by gel electrophoresis as well as by end-labeling DNA of splenocytes isolated from control and morphine treated rats. Splenocytes from morphine treated rats showed a classical ladder pattern with integer multiples of 180 base pairs. Splenocytes from morphine treated rats also showed increased mRNA expression of cathepsin-B, a gene associated with active cell death. These results suggest that morphine may also be modulating immune function by enhancing apoptosis of splenocytes.

Age and sex modulate renal expression of SGP-2 and transglutaminase and apoptosis of splenocytes, thymocytes, and macrophages

BACKGROUND

Aging in humans has been associated with the progressive loss of renal mass. This has been considered to account for a significant reduction of glomerular filtration rate in the aging population. In addition, aging is associated with a compromised immune system. Macrophages, thymocytes, and splenocytes play an important role in the maintenance of the immune system. We studied the effect of sex and aging on apoptosis of peritoneal macrophages, thymocytes, and splenocytes. In addition, we also studied the effect of sex and aging on mRNA expression of active cell death genes on the renal cortex.

METHODS

Rats in groups of 4 to 12 were killed at ages 2, 14, 30, 50, 75, and 100 weeks. Renal cortices, peritoneal macrophages, thymocytes, and splenocytes were isolated. DNA was isolated and run on agarose gel electrophoresis. Apoptosis of renal cells was evaluated by the TUNEL method and transmission electron microscopy. RNA was isolated from renal cortices and probed with specific cDNA probes for genes associated with active cell death, such as SGP-2, cathepsin-B, and tissue transglutaminase. Mesangial cells (MC) derived from younger and older rats were examined for the occurrence of apoptosis. The effect of estradiol and testosterone was studied on mesangial cell apoptosis.

RESULTS

At 2 weeks, peritoneal macrophages, thymocytes, and splenocytes showed no DNA fragmentation. Apoptosis of macrophages, splenocytes, and thymocytes increased with age in the males as well as females. Mesangial cells derived from aged rats showed a greater percentage of apoptosis when compared to MC derived from younger rats. Estradiol and testosterone directly affect mesangial cell apoptosis. Renal cortices of male rats showed enhanced mRNA expression of SGP-2 and tissue transglutaminase with aging; whereas expression of cathepsin-B peaked at 30 weeks in both male and female rats.

CONCLUSION

Age and sex modulate renal cortical mRNA expression of genes associated with active cell death. Age and sex also modulate apoptosis of macrophages, splenocytes, and thymocytes.

Biological variability in the structures of diphosphoinositol polyphosphates in Dictyostelium discoideum and mammalian cells

Previous structural analyses of diphosphoinositol polyphosphates in biological systems have relied largely on NMR analysis. For example, in Dictyostelium discoideum, diphosphoinositol pentakisphosphate was determined by NMR to be 4- and/or 6-PPInsP5, and the bisdiphosphoinositol tetrakisphosphate was found to be 4, 5-bisPPInsP4 and/or 5,6-bisPPInsP4 [Laussmann, Eujen, Weisshuhn, Thiel and Vogel (1996) Biochem. J. 315, 715-720]. We now describe three recent technical developments to aid the analysis of these compounds, not just in Dictyostelium, but also in a wider range of biological systems: (i) improved resolution and sensitivity of detection of PPInsP5 isomers by microbore metal-dye-detection HPLC; (ii) the use of the enantiomerically specific properties of a rat hepatic diphosphatase; (iii) chemical synthesis of enantiomerically pure reference standards of all six possible PPInsP5 isomers. Thus we now demonstrate that the major PPInsP5 isomer in Dictyostelium is 6-PPInsP5. Similar findings obtained using the same synthetic standards have been published [Laussmann, Reddy, Reddy, Falck and Vogel (1997) Biochem. J. 322, 31-33]. In addition, we show that 10-25% of the Dictyostelium PPInsP5 pool is comprised of 5-PPInsP5. The biological significance of this new observation was reinforced by our demonstration that 5-PPInsP5 is the predominant PPInsP5 isomer in four different mammalian cell lines (FTC human thyroid cancer cells, Swiss 3T3 fibroblasts, Jurkat T-cells and Chinese hamster ovary cells). The fact that the cellular spectrum of diphosphoinositol polyphosphates varies across phylogenetic boundaries underscores the value of our technological developments for future determinations of the structures of this class of compounds in other systems.

Increased expression of EGFR in gastric mucosa of aged rats

Although in Fischer-344 rats aging is found to be associated with increased gastric mucosal proliferative activity, little is known about the intracellular events that regulate this process. The present investigation examines the age-related changes in gastric mucosal tyrosine kinase activity and expression of epidermal growth factor receptor(EGFR) and its structural and functional analog p185c-erbB-2, the protein product of c-erbB-2/c-neu protooncogene. We observed a significantly higher intrinsic tyrosine kinase activity and tyrosine phosphorylation of EGFR and p185c-erbB-2 in the gastric mucosa of 24-mo-old (aged) rats than in that of their 4- or 12-mo-old counterparts. This was associated with increased levels of EGFR protein and steady-state mRNA levels of EGFR and p185c-erbB-2. In addition, we also observed threefold higher steady-state mRNA levels of transforming growth factor-alpha (TGF-alpha; one of the primary ligands of EGFR) in the gastric mucosa of aged rats than in that of 4-mo-old (young) animals. This was accompanied by a fivefold increase in the relative concentration of the 18-kDa precursor form of TGF-alpha in gastric mucosal membranes but not in the cytosol. In conclusion, our data demonstrate that aging is associated with increased tyrosine kinase activity of EGFR and p185c-erbB-2 in the gastric mucosa. Moreover, the observation that aging results in increased accumulation of TGF-alpha in gastric mucosal membranes raises the possibility that the membrane-bound TGF-alpha could partly be responsible for the constitutively active EGFR-induced signaling pathway in the gastric mucosa of aged rats and, in turn, for stimulation of mucosal proliferative activity.

HIV-1 gp160 envelope protein modulates proliferation and apoptosis in mesangial cells

Mesangial cell (MC) hyperplasia and accumulation of extracellular matrix are the predominant features of HIV-associated nephropathy (HIVAN). Since mice transgenic for HIV-1 genes show renal lesions mimicking HIVAN, we studied the effect of HIV-1 gp160 protein on cultured murine MC (MMC) proliferation and apoptosis. HIV-1 gp160 protein stimulated (p < 0.001) MMC proliferation when compared with control MMCs. This effect of gp160 protein peaked at a concentration of 0.01 microg/ml. MMCs treated with a higher concentration of gp160 protein (0.1 microg/ml) or for a prolonged period of time (72 h) showed apoptosis rather than cell proliferation. These studies were further confirmed by DNA fragmentation and end labeling assays. gp160 also enhanced apoptosis in human MCs. Tumor necrosis factor (TNF)-alpha enhanced (p < 0.001) MMC apoptosis, and anti-TNF-alpha antibodies inhibited gp160-induced MMC apoptosis. In addition, gp160 protein attenuated MMC expression of Bcl-2 mRNA expression. These results suggest that gp160-induced apoptosis may be affected in part by the release of TNF-alpha and associated with attenuated mRNA expression of Bcl-2 by MMCs.

Native and oxidized low density lipoproteins modulate mesangial cell apoptosis

Hyperlipidemia has been demonstrated to contribute to hypercellularity of the mesangium in experimental animal models of glomerulosclerosis. We studied whether it also has the potential to convert a hypercellular mesangium into a hypocellular one by inducing mesangial cell (MC) apoptosis. Low density lipoprotein (LDL) enhanced (P < 0.001) mouse mesangial cell (MMC) proliferation at lower concentrations (control, 10.3 +/- 0.3 vs. LDL 100 micrograms/ml, 24.2 +/- 0.3 x 10(4) cells/ml) but augmented (P < 0.001) apoptosis at higher concentrations (control, 5.6 +/- 0.5% vs. LDL, 500 micrograms/ml 26.2 +/- 3.4% apoptotic cells/field). Oxidized (OX) LDL enhanced MMC apoptosis in concentrations of 50 to 200 micrograms/dl. There was a direct relationship between MMC apoptosis and oxidation of LDL as judged by measuring thiobarbituric acid reactive species (TBARS). Since superoxide dismutase (SOD) attenuated (P < 0.001) LDL-induced MMC apoptosis, it seems to be mediated through the generation of free radicals by mesangial cells (control, 4.3 +/- 1.5%; LDL, 200 micrograms/ml, 19.4 +/- 0.5%; LDL + SOD, 8.1 +/- 1.3% apoptotic cells/field). LDL also induced a similar effect on human mesangial cells. These studies were further confirmed by DNA fragment assays and ELISA for programmed cell death. LDL treated cells also showed enhanced mRNA expression for RSG-2, a marker for active cell death. These in vitro results provide a basis for the speculation that LDL has the potential to cause an initial hypercellular and subsequent hypocellular mesangium in the course of the development of glomerulosclerosis.

Comparison of captopril-thiazide and enalapril-thiazide combinations in the management of mild to moderate black hypertensive patients: how important is diuretic dose and duration of action of the ACE-inhibitor?

A double-blind, randomized, parallel-group study was performed to compare the efficacy and tolerability of captopril-thiazide and enalapril-thiazide combinations. After a 3-week placebo run-in period, 47 Black patients with mild to moderate essential hypertension (mean 24-hour diastolic blood pressure (BP) > 90 mmHg and < 115 mmHg) were randomized to receive 1 of 2 combination tablets: captopril 50 mg plus hydrochlorothiazide 25 mg (CAP, n = 24) or enalapril 20 mg plus hydrochlorothiazide 12.5 mg (COR, n = 23) once daily. After 12 weeks of active treatment the mean 24-hour ambulatory BP was reduced from 152 +/- 11/99 +/- 6 to 133 +/- 13/86 +/- 7 mmHg (p < 0.005) in the CAP group and 157 +/- 15/100 +/- 6 to 141 +/- 18/90 +/- 12 in the COR group (p < 0.005). Target BP (24-hour diastolic BP < 90 mmHg) was achieved in 75% (18/24) of patients on CAP and 48% (11/23) on COR (p = n.s.). 24-hour BP load fell significantly with both CAP (from 69% to 34%, p < 0.001) and COR (from 67% to 37%, p < 0.001). Left ventricular mass index decreased by 7% with CAP and 11% with COR. Cardiac index and fractional shortening remained essentially unchanged in both groups. Both treatments were well tolerated and overall incidence of side effects was very low. It is concluded that both CAP and COR are effective, safe first-line antihypertensive choices in Black patients with mild to moderate hypertension with the former showing a trend towards greater efficacy than the latter.

Nitric oxide stimulates the activity of a 72-kDa neutral matrix metalloproteinase in cultured rat mesangial cells

We recently demonstrated that stimulation of inducible nitric oxide synthase (iNOS) activity reduced the accumulation of collagen and fibronectin in cultured rat mesangial cells. Therefore, we examined whether nitric oxide (NO) influenced the activity of a 72 kDa neutral matrix metalloproteinase by these cells in vitro. Enzyme activity was assessed in a biotin-avidin ELISA and by zymography. Exposure of mesangial cells to the cytokines, interferon (IFN)-gamma and lipopolysaccharide (LPS), increased gelatinolytic activity by 325 +/- 60% (P < 0.025). Co-incubation with 20 mM L-arginine caused a further increase in matrix metalloproteinase levels. Addition of L-NAME, an inhibitor of iNOS, reversed the IFN-gamma/LPS-induced rise in gelatinolytic activity. Incubation with the exogenous NO donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP), resulted in a dose dependent increase in metalloproteinase activity (P < 0.01). The NO-induced changes in metalloproteinase activity were also demonstrable by zymography. These data indicate that NO modulates the activity of a 72 kDa neutral matrix metalloproteinase and suggest that altered NO production may contribute to the development of glomerulosclerosis and tubulointerstitial fibrosis in chronic renal disease states.

Effects of amlodipine on 24-hour ambulatory blood pressure profiles, electrocardiographic monitoring, and left ventricular mass and function in black patients with very severe hypertension

In a 3-month, open-label study, 54 consecutive black patients with very severe hypertension were treated with amlodipine. Very severe hypertension was defined as an average sitting diastolic blood pressure (BP) > or = 115 mmHg and < or = 140 mmHg as a mean of 10 readings over a 30-minute period using an automatic BP measuring device and a mean 24-hour diastolic ambulatory blood pressure (ABP) > or = 110 mmHg and < or = 140 mmHg). Serial changes in 24-hour ABP and electrocardiographic monitoring, left ventricular (LV) mass index, and LV systolic function were evaluated. Mean 24-hour ABP was reduced from 181 +/- 14/119 +/- 6 to 140 +/- 15/92 +/- 9 mmHg at 3 months (P < 0.0001). Target BP (mean 24-hour diastolic ABP < 90 mmHg) was achieved in 35% of the patients. The reduction in BP was sustained for 24 hours after drug administration. Simultaneous BP measurements using the automatic BP measuring device were significantly different from the ABP measurements before and after treatment, suggesting a marked "white coat" pressor effect. At baseline, frequent or complex ventricular arrhythmias (> 30 ventricular extrasystoles per hour, ventricular couplets) were present in 2 (4%) patients, with no significant change after treatment. Left ventricular mass index regressed from 140 +/- 50 to 111 +/- 30 g/m2 at 3 months (P < 0.03); LV performance was not adversely affected. Adverse effects were few and tended to disappear during the treatment period. All of the clinical laboratory parameters tested remained unchanged. In this group of patients, treatment with amlodipine showed a marked and sustained antihypertensive action as demonstrated by 24-hour ABP monitoring, and was well tolerated and associated with LV mass regression without adverse effect on systolic cardiac function. Further, a low rate of complex ventricular arrhythmias was documented.

Recombinant tissue plasminogen activator for the treatment of lower extremity peripheral vascular occlusive disease

PURPOSE

Regional thrombolysis in the recanalization of peripheral vascular occlusive disease is an increasingly accepted therapeutic modality. Efficacy and complication rate are major issues in thrombolytic therapy. This prospective study was undertaken to determine if locally delivered recombinant tissue plasminogen activator (r-TPA) is safe and effective in clot lysis at non-weight-adjusted doses.

PATIENTS AND METHODS

Twenty patients (undergoing 21 infusions) from two centers underwent fibrinolytic therapy with use of r-TPA, at a dose rate of 2 mg/h. The mean duration of arterial occlusion was 27.2 days (range, 1-117 days). Concomitant intravenous heparin anticoagulation was administered to all patients. A coaxial infusion delivery system was employed. Hematologic parameters and angiographic follow-up were evaluated at 4-hour intervals during thrombolytic infusion. The chosen maximum r-TPA dose of 40 mg could be extended at investigator discretion.

RESULTS

Complete clot lysis was achieved in 18 of 21 (85.7%) infusions at a mean total dose of 38.9 mg (range, 8-84 mg). The mean infusion duration was 19.7 hours. In 16 of 19 (84.2%) infusions, in which the nadir fibrinogen level was recorded, it remained greater than 65% of baseline. Three of 21 (14.3%) infusions resulted in three major bleeding complications, one of which resulted in death.

CONCLUSION

In this two-center trial, catheter-directed r-TPA infusion at 2 mg/h is effective for clot lysis. When combined with concomitant heparin administration, this treatment may result in an unacceptably high frequency of bleeding complications.

A comparison of speech audiometry and pure tone audiometry in patients with secretory otitis media

Speech audiometry was performed on 15 children with secretory otitis media pre- and post-operatively and the findings compared with the pre- and post-operative pure tone audiograms. The results showed that in 30 per cent of cases pre-operatively the speech audiogram suggested a significantly worse hearing ability than that suggested by the pure tone audiogram (PTA). Where a PTA gives a borderline threshold disproportionate parental concern should be taken seriously as the hearing ability may well be worse than the PTA suggests.

4-Aminopyridine in chronic spinal cord injury: a controlled, double-blind, crossover study in eight patients

The potassium channel blocking drug 4-aminopyridine (4-AP) was administered to eight patients with chronic spinal cord injury, in a therapeutic trial based on the ability of the drug to restore conduction of impulses in demyelinated nerve fibers. The study was performed using a randomized, double-blind, crossover design, so that each patient received the drug and a vehicle placebo on different occasions, separated by 2 weeks. Drug and placebo were delivered by infusion over 2 h. An escalating total dose from 18.0 to 33.5 mg was used over the course of the study. Subjects were evaluated neurologically before and after the infusion. Two subjects returned for a second trial after 4 months and were examined daily for 3 to 4 days following drug infusion. Side effects were consistent with previous reports. Administration of the drug was associated with significant temporary neurologic improvement in five of six patients with incomplete spinal cord injury. No effect was detected in two cases of complete paraplegia and one of two severe incomplete cases (Frankel class B). Improvements in neurologic status following drug administration included increased motor control and sensory ability below the injury, and reduction in chronic pain and spasticity. The effects persisted up to 48 h after infusion of the drug, and patients largely returned to preinfusion status by 3 days. Compared with the more rapid elimination of the drug, these prolonged neurologic effects appear to involve a secondary response and are probably not a direct expression of potassium channel blockade.

Viral infection of the thymus

We have examined infection of the thymus during congenitally acquired chronic lymphocytic choriomeningitis virus (LCMV) infection of mice, a classic model of antigen-specific T-cell tolerance. Our results show that (i) infection starts at the fetal stage and is maintained throughout adulthood, and (ii) this chronic infection of the thymus can be eliminated by transfer of virus-specific cytotoxic T lymphocytes (CTL) that infiltrate the thymus and clear all viral products from both medullary and cortical regions. Elimination of virus from the thymus results in abrogation of tolerance. During the fetal stage, the predominant cell type infected is the earliest precursor of T cells with a surface phenotype of Thy1+ CD4- CD8- J11d+. In the adult thymus, infection is confined primarily to the cortisone-resistant thymocytes present in the medullary region. The infected cells are CD4+ and J11d+. The presence of J11d, a marker usually associated with immature thymocytes, on infected single positive CD4+ "mature" thymocytes is intriguing and suggests that infection by this noncytolytic virus may affect development of T cells. There is minimal infection of the CD8+ medullary thymocytes or of the double positive (CD4+ CD8+) cells present in the cortex. Infection within the cortex is confined to the stromal cells. Interestingly, there is infection of the double negative (CD4- CD8-) thymocytes in the adult thymus, showing that even during adulthood the newly developing T cells are susceptible to infection by LCMV. Virus can be eliminated from the thymuses of these carrier mice by adoptive transfer of medullary region first and then from the thymic cortex. This result clearly shows the need to reevaluate the widely held notion that mature T cells are unable to reenter the thymus. In fact, in our experiments the donor T cells made up to 20 to 30% of the total cells in the thymus at 5 to 7 days after the transfer. The number of donor T cells declined as virus was eliminated from the thymus, and at 1 month posttransfer, the donor T cells were hardly detectable. The results of this study examining the dynamics of viral infection and clearance from the thymus, the primary site of T-cell development, have implications for understanding tolerance induction in chronic viral infections.

Complications of the transsphenoidal approach to sellar lesions

Transsphenoidal surgery is currently performed extensively for lesions of the sella turcica. The mortality and morbidity of this surgical approach are minimal, and the results satisfactory overall. Only a few studies have addressed the complications of this approach. The authors present a retrospective study of 200 transsphenoidal procedures in 196 patients over an eleven year period. There was one death due to meningitis. Major morbidity consisted of intraventricular hemorrhage in three patients, false aneurysm of the internal carotid artery in one patient and thalamic infarction in another patient. Minor morbidity details are presented. The pathogenesis of the most serious of these complications along with possible preventive measures are discussed.

New insecticidal metabolites from soil isolate W719

In the course of screening soil organisms for new insecticidal metabolites, strain W719 was found to produce a group of metabolites active against the tobacco budworm Heliothis virescens. The active metabolites were purified by a combination of solvent partitioning and chromatographic steps, and the physico-chemical properties and insecticidal activity of the main components were determined. The two main components have MW's of 925 and 939, appear to belong to the macrocyclic lactam family of natural products, and possess significant insecticidal activity.

Results of a recently instituted programme of thrombolytic therapy in acute lower limb ischaemia

Twenty-eight patients with acute lower limb ischaemia received low dose intra-arterial thrombolytic therapy over a 2-year period. Eighteen patients received streptokinase and ten patients received recombinant tissue plasminogen activator (rTPA). Indications included arterial thromboemboli and graft failures. Mean ischaemic times were similar in both groups. Treatment time to achieve lysis was significantly less with rTPA (P less than 0.01). Subsequent vascular procedures, including angioplasty or reconstruction, were undertaken in 36 per cent of patients. Arterial puncture site bleeding occurred in eight (29 per cent) patients. Three (11 per cent) patients suffered rethrombosis after initial successful lysis. All rethromboses were successfully lysed with rTPA. There were two major amputations. Five (18 per cent) patients died, all lytic failures in the streptokinase treatment group. There were no cerebral haemorrhagic events and no patient died as a result of thrombolytic therapy. Good clinical outcome was obtained in nine of 18 patients treated with streptokinase and in nine of ten patients treated with rTPA. Intra-arterial thrombolysis provides effective therapy with high rates of limb salvage and a low mortality rate. This study suggests that rTPA may be a more effective agent, causing less morbidity, than streptokinase.

Differentiation-related regulation of 1,25-dihydroxyvitamin D3 receptor mRNA in human leukaemia cells HL-60

Vitamin D receptor (VDR) is a nuclear protein which mediates the physiological actions of its hormone ligand, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). While it appears that the receptor-hormone complex regulates the expression of hormone-dependent genes involved in mineral homeostasis, its role in induction of differentiation of leukaemic cells is less clear. We have studied the expression of the VDR gene in several sublines of HL-60 leukaemic cells with varying responsiveness to 1,25(OH)2D3. Sublines which rapidly differentiated to monocytic forms were shown to contain elevated steady-state levels of VDR mRNA within 1 h of exposure to high concentration of 1,25(OH)2D3. This up-regulation of the expression of VDR was not apparent in sublines in which monocytic differentiation occurred after a delay of several days. Beginning at approximately 3 h after exposure to 1,25(OH)2D3 in most cases, there was a gradual decline in VDR mRNA levels. Measurement of steady-state levels of mRNA for c-myc and c-fos showed that in sublines of HL-60 cells which respond rapidly to 1,25(OH)2D3, elevation of VDR mRNA is evident prior to the changes in proto-oncogene expression. These data are consistent with the hypothesis that a change in VDR gene expression is one of the steps that promote monocytic differentiation.

Selective regional chemotherapy of unresectable hepatic tumours using lipiodol

Over a 30 month period from 1987 to 1990, selective hepatic cannulation under fluoroscopic control was performed in 57 consecutive patients with primary and secondary malignancies of the liver. Fifty-three patients were subsequently treated using intra-arterial Lipiodol emulsified with epirubicin. The tumours treated were hepatocellular carcinoma (n = 35), metastatic adenocarcinoma (n = 14), intrahepatic cholangiocarcinoma (n = 3) and leiomyosarcoma (n = 1). For hepatocellular carcinoma the cumulative survival was 38% at one year; the median survival was 12.2 months for Stage I, 6.3 months for Stage II and 0.9 months for Stage III tumours. In metastatic disease the cumulative survival was 63% at one year. These data suggest that targeted intra-arterial chemotherapy with Lipiodol-epirubicin is a useful palliative therapy for patients with Stage I and II HCC, and that a controlled trial of this treatment should be undertaken.

Carotid artery dissection secondary to seatbelt trauma: case report

A postmortem report of a patient with traumatic internal carotid artery dissection, along with evidence strongly suggestive of a car seatbelt as a causative factor, is presented. In this 5-foot subject, the shoulder harness could have been high, over the anterior cervical area. The authors feel this mechanism deserves consideration as one of the important causes of traumatic carotid dissection. If supported by further studies, remedial measures in the form of changes in seatbelt design, or the use of alternate protective measures may be warranted.

Delayed and progressive multiple suture craniosynostosis

A considerable amount of information is available on various types of craniosynostoses. The patient exhibiting single suture synostosis that progresses to involve multiple sutures is distinctly uncommon, as is the patient exhibiting delayed synostosis involving all of the calvarial sutures. We report a group of 11 such patients with progressive and delayed holocalvarial synostosis. Most patients exhibited features of raised intracranial pressure or developmental delay, and in all patients symptoms were relieved after surgery. The diagnostic and therapeutic implications of this type of presentation in craniosynostosis are discussed.

False aneurysm of the cavernous carotid artery: a complication of transsphenoidal surgery

Although excellent results currently are being achieved with transsphenoidal surgery, life-threatening complications may occasionally result from this approach. We present a patient with carotid injury sustained during transsphenoidal surgery, who presented 6 weeks postoperatively with a large false aneurysm in the cavernous part of the right internal carotid artery. This lesion was successfully treated by trapping. The pathogenesis of this complication is discussed and the relevant literature is reviewed.

Insulin-receptor gene and its expression in patients with insulin resistance

We studied the structure of the insulin-receptor gene in normal individuals and in four unrelated patients with leprechaunism (Minn-1, Ark-1, Ark-2, Can-1) and four unrelated patients with the type A syndrome of insulin resistance, both disorders associated with genetic alterations in affinity, binding capacity, and kinase activity of the insulin receptor. Genomic cloning and Southern blot analysis indicate that the normal human insulin-receptor gene is greater than or equal to 150 kilobases long and consists of a minimum of 17 exons, 6 in the genomic region of the alpha-subunit and 11 in the region of the beta-subunit. Three of the patients, one with leprechaunism and two with type A syndrome, have decreases in insulin-receptor mRNA but on genomic blot analysis have no obvious abnormalities in the insulin-receptor gene. No distinctive pattern of restriction-fragment-length polymorphisms or evidence for major insertion or deletion mutations of the insulin-receptor gene was found in any of the patients. These data indicate that the insulin-receptor gene is greater than 35 times larger than coding regions and has a complex structure. Although leprechaunism and type A syndrome are most likely due to defects in the structure and expression of the insulin-receptor gene, they are likely to be associated with specific point mutations rather than major changes in gene structure.