Cryptosporidium parvum infection requires host cell actin polymerization

The intracellular protozoan parasite Cryptosporidium parvum accumulates host cell actin at the interface between the parasite and the host cell cytoplasm. Here we show that the actin polymerizing proteins Arp2/3, vasodilator-stimulated phosphoprotein (VASP), and neural Wiskott Aldrich syndrome protein (N-WASP) are present at this interface and that host cell actin polymerization is necessary for parasite infection.     

The effects of complement activation by cobra venom factor on the migration of T and B lymphocytes into rat thoracic duct lymph.

Experiments were done to see whether C3 or C3-split products are involved in lymphocyte recirculation, with particular reference to B lymphocytes which have C3b receptors. Rats were injected with cobra venom factor (CVF), and the output of subclasses of lymphocytes was measured in thoracic duct lymph in hourly collections during the subsequent 24 h. During the period of acute C3 activation which lasted for 2-8 h, the output of lymphocytes decreased by 47%, but returned to normal at later times, when C3 levels were reduced to less than 20% normal. There was no effect on the output of C3b receptor lymphocytes, and this receptor was not blocked probably because initial C3 levels in lymph were only 13% of blood levels, so that only small amounts of C3b were generated in lymph. When these lymphocytes were labelled and injected i.v. they migrated with the slow rate which is characteristic of normal B lymphocytes. The main effect of CVF was to reduce the output of T lymphocytes by 58% during the phase of acute C3 activation. When normal thoracic duct lymphocytes were labelled and injected, their rate of reappearance in thoracic duct lymph was only reduced during this phase. It was concluded that recirculation of lymphocytes is not C3 dependent, and that insufficient C3b is generated in lymphoid tissues to block C3b receptors on B lymphocytes during periods of rapid C3 activation. However the migratory rate of T lymphocytes through these tissues is reduced during this period, and it is suggested that this may be due to an effect of C3 split products on macrophages which lie along T-lymphocyte traffic routes.     

Depression among patients with a chief complaint of chronic fatigue

The prevalence of mood disorders among patients with chronic fatigue was examined in a group of 100 adults who had experienced fatigue symptoms for an average of 13 years. Patients received a comprehensive history, physical and laboratory evaluation and completed the National Institute of Mental Health Diagnostic Interview Schedule and the Beck Depression Inventory (BDI). Among 44 patients with depressive illness, the onset of their first depressive episode was strongly associated with and preceded the onset of chronic fatigue. The BDI, fatigue history, demographic factors, and findings from the physical examination and laboratory had only modest success in discriminating those patients with depressive illness from other patients. We conclude that depressive illness is an important precursor of chronic fatigue.     

The effect of peritoneal macrophage-derived factor(s) on ovarian progesterone secretion and LH receptors: the role of calcium.

Macrophages and their secretory products, cytokines, play an integral role in many reproductive processes. In this study we examined the effect of conditioned media from cultured human peritoneal macrophages on progesterone production by granulosa cells and the role of calcium in this process. Macrophages were pretreated with various concentrations of a calcium channel blocker (verapamil) or a calcium ionophore (A23187). Macrophage-conditioned media (MCM) or cell-free media that contained calcium channel modifiers were added at three dose levels to cultured porcine granulosa cells. Progesterone production and LH receptor content were determined. Macrophage-conditioned media alone elevated basal progesterone production, but significantly attenuated granulosa cell LH receptor content. These effects were neither potentiated nor suppressed by pretreating macrophages with verapamil. However, production of the LH receptor lowering factor(s) appeared to be suppressed by calcium ionophore. We conclude that (1) one or more factors produced by macrophages have a net stimulatory effect on basal progesterone production and these factor(s) may not be calcium-dependent and (2) macrophage-derived secretory products reduce granulosa cell LH receptor content. The production of these factor(s) may be calcium-dependent.     

X-linked codominant genes control all types of non-major histocompatibility complex-restricted cytotoxicity

In most individuals, natural killer (NK) activity is abolished after lymphocyte irradiation with 3,000 cGy, while lymphocytes from a minority of males retain 100% NK activity and lymphocytes from some females retain 50% NK activity after this dose. Radiation sensitivity of NK activity is controlled by X-linked codominant genes. The frequency of the allele that imparts resistance is 7%. We studied a unique family in which both parents have the resistant allele such that the father is completely resistant and the mother is partially resistant. The three offspring of this couple were one sensitive male, one partially resistant female, and one completely resistant female. The radiation sensitivity of nonspecific cytotoxic functions mediated by various types of effector cells from all five family members were evaluated in order to determine whether other cytotoxic functions were controlled by the same set of genes. The cytotoxic functions investigated were: NK and lymphokine-activated killing, anomalous killing and lectin-dependent cellular cytotoxicity, and antibody-dependent cell-mediated cytotoxicity. Our data indicate that the radiation sensitivity of all types of nonspecific cytotoxic cells is under the same genetic control.     

Seroresponses to human papillomavirus types 16, 18, 31, 33, and 45 virus-like particles in South African women with cervical cancer and cervical intraepithelial neoplasia

The aim of the study was to determine the prevalence of antibodies to human papillomavirus (HPV) types 16, 18, 31, 33, and 45 in woman in Cape Town with cervical intraepithelial neoplasia (CIN) (n = 95), cervical cancer (n = 40), female blood donors (n = 95) and children (n = 110). The enzyme-linked immunosorbent assay (ELISA) made use of baculovirus synthesised HPV virus like particles (VLPs) as antigen. Antibodies to at least one HPV type were detected in sera from 75% of cancer patients, 71.6% of CIN patients, 44.2% of blood donors and 27.3% of children. Sera from 95 women with CIN were compared with age-matched female blood donors. There was a significant association of seropositivity to VLP-16 (P = 0.006) and VLP-45 (P = 0.008) with CIN compared with the blood donors. There was also a significant difference in the seropositivity of women with CIN to any of the five virus-like particle (VLP) types compared to the blood donors (P = 0.0002: OR = 3.2). Thirty-nine of sixty-nine (56.5%) women with CIN were found to be HPV-16 DNA positive. The average age of women in this group that were VLP-16 seropositive was 34 years and those found to be VLP-16 seronegative was 52 years of age. Antibodies to all five VLP types were detected in these populations, thus an ideal vaccine should induce protection from infection by a wide range of HPV types.     

Interlaboratory and intralaboratory comparisons of indirect immunofluorescence assays for serodiagnosis of Lyme disease.

A conventional indirect immunofluorescence assay (IFA) and an anticomplement indirect immunofluorescence assay (ACIF) for detecting serum antibodies to Borrelia burgdorferi in humans were evaluated during a prevalence survey in northern California. Sera obtained from 119 current or former residents of an area in which Lyme disease is endemic were split and tested by the IFA in two laboratories and the ACIF in a third. The seropositivity rate ranged from 15 to 20% with 88 to 93% agreement among laboratories. Interlaboratory agreement was statistically highly significant in each of the three pairwise comparisons and was positively associated with clinical manifestations of Lyme disease. Intralaboratory agreement ranged from 93 to 96% in two laboratories and was also statistically highly significant. Immunoblotting confirmed 100 of 101 of the nondiscrepant immunofluorescence test results and likewise was positively correlated with the degree of interlaboratory agreement. The ACIF was found to be a highly specific test (100% specificity) with a much lower cutoff titer (1:8) than the conventional IFA (determined to be 1:128 or 1:256 in two laboratories) for detecting antibodies to B. burgdorferi. It also appeared to be more sensitive (80 versus 68%) than the IFA as determined by comparative immunoblotting, though the absolute sensitivity of the ACIF for serodiagnosis of early Lyme disease has yet to be determined. Significant serologic cross-reactivity was demonstrated between B. burgdorferi, Borrelia coriaceae, and Borrelia hermsii by the IFA, which may confound spirochetal serosurveys in California where all three spirochetes are known to coexist.     

Glucocorticoid resistance in asthma is associated with elevated in vivo expression of the glucocorticoid receptor beta-isoform

BACKGROUND: Glucocorticoid-resistant bronchial asthma is characterized by failure of corticosteroids to suppress key asthma-relevant, cell-mediated inflammatory responses in the airways. OBJECTIVE: The mechanism of this phenomenon is not clear but may involve aberrant expression of the beta-isoform of the glucocorticoid receptor. METHODS: We have measured expression of the alpha- and beta-glucocorticoid receptor isoforms in tuberculin-driven cutaneous cell-mediated inflammatory lesions in people with asthma who are glucocorticoid sensitive and resistant after 9 days of therapy with oral prednisolone (40 mg/day) or matching placebo in a random order, crossover design. RESULTS: After placebo therapy, the mean numbers of cells expressing glucocorticoid receptor alpha immunoreactivity in the lesions evoked in glucocorticoid-sensitive and -resistant patients with asthma were statistically equivalent. The numbers of cells expressing glucocorticoid receptor beta were significantly elevated in the patients who were glucocorticoid resistant, resulting in an 8-fold higher ratio of expression of glucocorticoid receptor alpha/glucocorticoid receptor beta in the patients who were glucocorticoid sensitive. Glucocorticoid receptor alpha/glucocorticoid receptors beta were colocalized to the same cells. Oral prednisolone therapy was associated with a significant decrease in the numbers of cells expressing glucocorticoid receptor alpha but not glucocorticoid receptor beta in the subjects who were glucocorticoid sensitive. No significant change was found in the numbers of cells expressing glucocorticoid receptor alpha and glucocorticoid receptor beta in the patients who were glucocorticoid resistant. Prednisolone therapy reduced the ratio of glucocorticoid receptor alpha/glucocorticoid receptor beta expression for the patients who were glucocorticoid sensitive to a level seen in the patients who were glucocorticoid resistant before therapy. CONCLUSION: Because glucocorticoid receptor beta inhibits alpha-glucocorticoid receptor-mediated transactivation of target genes, the increased expression of glucocorticoid receptor beta in inflammatory cells might be a critical mechanism for conferring glucocorticoid resistance.     

Alcohol use following liver transplantation: a comparison of follow-up methods

Alcoholic cirrhosis is one of the most common indications for liver transplantation. Previous researchers have studied rates of return to drinking following transplantation, however, few have employed prospective measures of alcohol use. The authors prospectively studied the alcohol use of patients transplanted for alcoholic liver disease. The authors improved the accuracy of monitoring alcohol use by using various methods for tracking patient's alcohol consumption, and we report on the time to first alcohol use after transplantation comparing these different methods. The authors found that alcohol use can occur very early after transplantation, even within the first 3 months posttransplant. Thirty-eight percent of the patients consumed any alcohol after transplantation. The clinical interviews by the psychiatrist were the most successful method for identifying posttransplant alcohol use. Posttransplant alcohol use was significantly associated with prior nonalcohol substance use (P < 0.025), family history of alcoholism in a first-degree relative (P < 0.025), and prior alcohol rehabilitation experience (P < 0.05) but not with a prior psychiatric history or less than 6 months of pretransplant sobriety. The authors indicate that prospective monitoring, using a combination of methods, is the most accurate approach to identify alcohol consumption. With this type of accuracy, risk factors can be identified and alcohol use can be compared with alcohol-related morbidity posttransplant.