Engineering a humanized bispecific F(ab')2 fragment for improved binding to T cells. We recently constructed a humanized bispecific antibody (BsF(ab')2v1) by separate E. coli expression of each Fab' arm followed by directed chemical coupling in vitro. BsF(ab')2 v1 (anti-CD3/anti-p185HER2) was demonstrated to retarget the cytotoxic activity of human CD3+ CTL in vitro against the human breast-tumor cell line, SK-BR-3, which over-expresses the p185HER2 product of the proto-oncogene HER2. Our minimalistic humanization strategy is to install as few murine residues as possible into a human antibody in order to recruit antigen-binding affinity and biological properties comparable to that of the murine parent antibody. This strategy proved very successful for the anti-p185HER2 arm of BsF(ab')2 v1. In contrast BsF(ab')2 v1 binds to T cells via its anti-CD3 arm much less efficiently than does the chimeric BsF(ab')2 which contains the variable domains of the murine parent anti-CD3 antibody. Here we have constructed additional BsF(ab')2 fragments containing variant anti-CD3 arms with selected amino acid replacements in an attempt to improve antibody binding to T cells. One such variant, BsF(ab')2 v9, was created by replacing 6 residues in the second hypervariable loop of the anti-CD3 heavy chain variable domain of BsF(ab')2 v1 with their counterparts from the murine parent anti-CD3 antibody. BsF(ab')2 v9 binds to T cells (Jurkat) much more efficiently than does BsF(ab')2 v1 and almost as efficiently as the chimeric BsF(ab')2. This improvement in the efficiency of T-cell binding of the humanized BsF(ab')2 is an important step in its development as a potential therapeutic agent for the treatment of p185HER2 over-expressing cancers.


Janusin: new molecular design for bispecific reagents. It is well established that soluble CD4 (sCD4) inhibits HIV infection in vitro, regardless of the virus strain or genetic variant. Most effective molecules, thus far, based on sCD4 are those in which CD4 is combined with immunoglobulin constant regions (CD4-IgG or CD4-IgM). Such molecules maintained HIV-gp120 specificity mediated by CD4 and also antibody effector functions such as complement activation, Fc receptor binding, long serum half-life or transport across the placental barrier. We have now developed sCD4 molecules which are even more potent anti-HIV reagents. These molecules are based on the principle of bispecific antibodies and they have properties capable of retargeting cytotoxic T lymphocytes onto HIV-infected cells and inducing efficient killing. CD4 combined with anti-human CD3 (FvCD3) single-chain combining site has been produced (CD4-FvCD3-JANUSIN). This molecule shows the expected biological activities, namely, binding to the 2 ligands, human CD3 and gp120, also efficiently retargeting CTLs of any specificity onto HIV-infected cells. In addition, several advantages over classical bispecific antibodies can be achieved: only one polypeptide, not a mixture containing the desired product, is produced, thus simplifying the purification process. In addition, Janusin designs do not contain the Ig Fc portion, which could mediate illegitimate retargeting of T-cells. In addition to CD4-FvCD3-JANUSIN, receptor-Fv, Fv-Fv or ligand-Fv Janusins can be produced.


Functional assembly of chimeric T-cell receptor chains. We have generated cytotoxic T-cell hybridomas expressing chimeric T-cell receptors (cTCR) with an antibody-type specificity for the TNP hapten. Transfectants expressing the cTCR genes could mediate specific lysis of haptenated tumor cell lines of various types and secrete IL-2 upon stimulation with TNP modified cells. In a previous report, we showed that double-gene transfectants expressing either VHC alpha and VLC beta or VHC beta and VLC alpha could be activated by TNP-modified stimulator cells or TNP proteins immobilized on plastic. Single-chain transfectants (expressing VHC alpha or VHC beta alone) could be mainly activated by TNP-cells. We now report that transfection of chimeric VHC alpha gene into an alpha-chain-defective mutant restores the surface expression of the TCR/CD3 complex. In parallel, such transfectants regained the ability to respond to mitogen and anti-CD3 antibodies and responded weakly to TNP cells. Double gene transfectants, bearing 2 complementary chimeric chains, expressed high amounts of cTCR on their surface, sufficient to acquire sound anti-TNP reactivity. Cells expressing the VHC beta gene only were not functional and had no detectable surface TCR chains. Taken together, our results suggest that chimeric VHC alpha chains can pair with endogenous V beta C beta chains, but that there is preferential association between complementary chimeric chains, resulting in higher functional expression of the chimeric TCR.


Bispecific-antibody-mediated targeting of radiolabeled bivalent haptens: theoretical, experimental and clinical results. Chemically conjugated bispecific (anti-cell surface antigen, anti-hapten) Fab'-Fab antibodies (Bs-MAbs) have been used to target 125I-, 111In- and 99mTc-labeled haptens to cell sub-sets. In vitro, bivalent haptens were found to bind more strongly than their monovalent analogs to the Bs-MAbs bound to ("ordered" on) the cell surface, or than to free ("disordered") Bs-MAbs: they are selective for cell-bound Bs-MAbs. In tumor-grafted nude mice models, the sequential injections of microgram amounts of Bs-MAb, and 1 day later, of microC amounts of bivalent haptens permits to sharply delineate small tumors (using a gamma camera), hours after injection. Further, the isotope biodistribution was found to be at least 3 times more selective for the tumor than that obtained with directly labeled anti-CEA F(ab)'2 or with monovalent haptens. This better in vivo selectivity of the 2-step targeting of bivalent haptens was also demonstrated in a pharmacokinetic study using therapeutic amounts of reagents. In primary-colon-carcinoma patients, a similar comparative immunoscintigraphy study confirmed the better selectivity of bivalent hapten targeting over direct targeting, on the basis of image quality and ex vivo tissue counting. In patients with medullary carcinoma of the thyroid, bivalent hapten targeting allowed us to confirm tumor extension and to find occult lesions. Interestingly, radio-immunoguided surgery was necessary to resect these small lesions. These experimental results, together with technological and theoretical considerations, suggest that Bs-MAb-mediated targeting of isotopes (or other agents) is one of the major ways to increase the clinical performance of MAb-based targeting diagnostic and therapeutic tools.


Novel surface molecules involved in human NK cell activation and triggering of the lytic machinery. Three new monoclonal antibodies (MAbs) termed 7A6, PP35 and A6/143 were isolated after mouse immunization with CD3- CD16+ NK clones. The screening procedure was based on the ability of MAbs to trigger cytolytic activity of the immunizing clones in a re-directed killing assay against the P815 murine mastocytoma cell line. The 7A6 MAb reacts with 58 kDa surface molecules that appear to belong to the same molecular family defined by the previously described NK-sub-set-specific GL183 and EB6 MAbs. However, unlike from these MAbs, the 7A6 MAb reacted with (and activated) all CD3- NK lymphocytes, independent of their sub-set assignment (based on the expression or lack of expression of EB6, GL183 and CD16). The PP35 MAb reacted with a 70 kDa surface molecule expressed on all CD3- NK cells, as well as on TCR gamma/delta + cells and on a small sub-set of TCR alpha/beta + CD8+ lymphocytes. The PP35 MAb induced activation of essentially all NK cells, although clonal analysis revealed quantitative differences in the magnitude of the cytolytic responses elicited in different clones. Finally, the A6/143 MAb reacted with a molecule of 115 kDa expressed by all human PBL. Similarly to 7A6 and PP35 MAbs, the A6/143 MAb activated all sub-sets of cloned NK cells.


Bispecific IgG and IL-2 therapy of a syngeneic B-cell lymphoma in immunocompetent mice. Bispecific antibody (bsAb) which binds to CD3 and a tumor-associated antigen can induce lysis of tumor cells by T cells. Lymphocytes targeted by bsAbs are also capable of inhibiting the growth of human xenografts in athymic mice. However, little is known about the impact of this form of therapy in immunologically intact animals. The 38C13 murine B-cell lymphoma model is well suited for the study of bsAb therapy. BsAb, consisting of an IgG that is monospecific for both CD3 and the idiotype expressed by V 38C13 cells, was obtained from hybrid-hybridoma supernatant. Immunocompetent C3H mice were inoculated with V 38C13 cells and treated 2 days later with antibody. Over 90% of mice treated with monospecific antibody died of lymphoma, while only 27% of mice treated with bsAb developed tumor and died. In studies of bsAb/IL-2 synergy, treatment was delayed until 5 days after inoculation to allow for a larger tumor burden at the time of treatment. IL-2 was administered on days 3 to 6. All mice treated with IL-2 alone died of lymphoma, as did 75% of mice treated with bsAb alone. Only 18% of mice treated with both bsAb and IL-2 developed lymphoma. Thus, therapy with bsAb and IL-2 eliminated a tumor load 100- to 1000-fold greater than can be eliminated by therapy with anti-tumor antibody alone. These studies demonstrate the value of using immunocompetent animal models, and support the further exploration of bsAbs as an immunotherapy for human malignancy.


Bispecific antibody therapy of two murine B-cell lymphomas. Numerous in vitro studies have shown that T lymphocytes can be targeted towards any target cell by using bispecific antibodies (bsAbs) with specificity of the CD3/TCR complex and a target cell antigen. We have produced bsAbs directed against the membrane expressed idiotype of the murine B cell lymphomas BCLI and 38C13, and murine CD3 complex. The dual specificity of the hybrid-hybridoma produced monoclonal antibodies (MAbs) could be demonstrated by flow cytometry, the induction of T cell proliferation, the induction of IL2 secretion by polyclonal T cells, and redirected lysis of the relevant target cells. Immunotherapy of tumor bearing animals demonstrated that bsAbs could efficiently target T cells towards the tumor cells, that tumor cell--T cell bridging is established in vivo, and that both T cell subsets contribute to tumor regression resulting in long-term survival and cure of the lymphomas.


CD4 immunoadhesins in anti-HIV therapy: new developments. CD4, the cell-surface receptor for the human immunodeficiency virus (HIV), is a member of the immunoglobulin (Ig) gene superfamily. It contains 4 extracellular sequences homologous to Ig variable domains, the first of which (V1) is sufficient for binding to HIV. To develop CD4 as an anti-HIV therapeutic, we engineered a CD4 immunoadhesin (CD4-IgG)--a fusion protein containing the V1 and V2 domains of CD4 with the hinge and Fc regions of human Ig heavy chain. A chimeric protein of this type has several advantages compared to the soluble receptor, including a greatly extended in vivo half-life and greater avidity for HIV; moreover, like an antibody, it performs effector functions via its Fc domains, such as complement activation and antibody-dependent cell-mediated cytotoxicity. In vivo experiments show that CD4-IgG protects against HIV-I IIIB infection of chimpanzees when administered prior to viral challenge. In addition, CD4-IgG is transferred efficiently across the placenta from mother to fetus in rhesus monkeys. To evaluate its safety in humans, we conducted a phase-I clinical trial in adult patients with AIDS and AIDS-related complex. We found that, in a total of 16 patients, administration of CD4-IgG was well tolerated at doses up to 1000 micrograms/kg of body weight, with no important clinical or immunological toxicities noted. Given its unique properties, particularly the ability of CD4-IgG to cross the placenta, we plan to focus future clinical efforts on preventing infection of newborns via maternal-fetal transfer of HIV.


Initial experience in treating human lymphoma with a combination of bispecific antibody and saporin. Results are presented showing the use of bispecific F(ab')2 antibodies (bsAbs) in the delivery of saporin for the treatment of 2 human B-cell malignancies. BsAbs delivering saporin through CD22, but not through CD19, were effective at inhibiting the uptake of [3H]leucine by Daudi and Raji cells. Furthermore, a combination of 2 anti-CD22 bsAbs, selected to bind simultaneously to saporin, bound saporin 20 times more avidly and inhibited protein synthesis far more efficiently than any single bsAb. In the first patient, with end-stage chronic lymphocytic leukaemia (CLL), treatment with 10 mg of saporin complexed to 100 mg of anti-CD19 bsAb over 43 days showed no therapeutic effect. In contrast, the second patient, with end-stage non-Hodgkin's lymphoma (NHL), given 5 mg of saporin complexed with a pair (50 mg) of anti-CD22 bsAbs over 15 days showed a marked clinical response, including complete clearance of tumour from the blood, clearance of ascites and shrinkage of tumour masses. Neither patient experienced any toxic side-effects, either during or after treatment. However, the second patient developed a strong anti-mouse Fab (HAMA) response 28 days after the treatment started. No anti-saporin response could be detected.


Adoptive immunotherapy of ovarian carcinoma with bs-MAb-targeted lymphocytes: a multicenter study. A bispecific monoclonal antibody (bs-MAb) (OC/TR) was produced in large quantities for the intraperitoneal (i.p.) treatment of ovarian cancer. The bs-MAb recognizes the folate-binding protein on ovarian cancer cells on the one hand and the CD3 activation site on T lymphocytes on the other. T lymphocytes were expanded ex vivo, targeted with OC/TR in vitro and administered to the i.p. cavity in the presence of soluble OC/TR. All patients developed human anti-mouse-antibodies (HAMA). In the Dutch study, 2 complete remissions (CR) were seen, 2 partial regressions (PR), I stable disease (SD) and I progressive disease (PD). In the Italian study 3 CR, I PR, I SD and 2 PD were seen.


Response of fetal and newborn piglets to maternal protein restriction during early or late pregnancy. Dietary protein restriction during pregnancy has an adverse effect on progeny development, although the importance of the time at which the nutritional insult occurs is unclear. The objective in our study was to test the hypothesis that severe protein restriction during the first trimester of swine pregnancy has a greater detrimental effect on fetal development than restriction in late pregnancy. On the day of mating, primiparous swine were assigned to control (C, 13% protein) or protein-restricted (PR, 0.5% protein) diets and fed in 4 regimens: 1) C diet throughout pregnancy (114 +/- 2 days) (n = 5), 2) PR diet to day 44, C diet to parturition (n = 6), 3) C diet to day 80, PR diet to parturition (n = 8), and 4) PR diet throughout pregnancy (n = 6). In addition, 6 pigs fed C and 7 pigs fed PR diets were killed at day 44 to assess placental and fetal development. Maternal diet had no effect on placental or fetal weight, crown-rump length, or heart girth circumference in 44-day fetuses. Mean birth weight of newborn piglets was 1462, 1291, 1262, and 1064 g for C, PR:C, C:PR, and PR groups, respectively (C greater than PR:C = C:PR greater than PR, p less than 0.01). Plasma total protein and albumin were less (p less than 0.01) in PR than in PR:C and C:PR; all three groups were less than C (p less than 0.01). Liver weight and total liver protein, RNA, and DNA followed the same pattern (C greater than PR:C = C:PR greater than PR, p less than 0.05). Longissimus muscle total protein, RNA, and DNA were greater in group C than in all other groups (p less than 0.01). Maternal protein restriction during early pregnancy produced less developmental impairment than restriction throughout pregnancy, but the magnitude of impairment was similar to that produced by restriction during only the third trimester. The effects of early restriction were manifested at birth, even though none of the indices of stunting were observed at 44 days when the maternal protein restriction was ended. Whether the effects of early versus late restriction show the same mechanism of action has not been determined.


A non-invasive technique for the accurate measurement of leg length in animals. A novel, non-invasive technique for accurate measurements in animals (Kyniklometry) is presented. Kyniklometry (derived from greek ŏ kúvikloz the rabbit) determines the distance between soft tissue landmarks in conscious rabbits, in particular the rear lower leg. Each measurement consists of six subsequent and independent estimations of this distance, with a technical error of 79 microns (study I), respectively 83 microns (study II). The angle of the relaxed sitting animal's knee is approximately 45 infinity, and remains individually almost constant during subsequent measurements. The precision of the device was compared with X-ray stereophotogrammetry (technical error 30 microns). Five female New Zealand White rabbits were measured for 13 consecutive days at 24-hour-intervals both by kyniklometry and X-ray stereophotogrammetry (study I). The mean increment of 5 kyniklometric series of ten (3rd to 13th day) 24-hour-increments was 0.988 mm, the mean 24-hour-variance was 0.244 mm2. Sixty point five percent of this variance could be explained by parallel right/left leg soft tissue variation. Only 5% of the variance was explicable by the technical error. The 24-hour-correlation between kyniklometry and X-ray stereophotogrammetry was significant with r = 0.889 and p less than 0.001. Kyniklometric measurements were also performed in 5 female rabbits for 56 days at 24-hour-intervals (study II). We found spontaneous periodicity once every 8 to 14 days. There was a diurnal variation of rear lower leg increment with maxima in the early morning hours.


Expression of transforming growth factor-beta (TGF-beta 1) and insulin-like growth factor II (IGF-II) messenger RNA in the developing subcutaneous tissue (SQ) of the fetal pig. Studies (in situ hybridization) were performed on the developing subcutaneous tissue (SQ) of the pig fetus to determine sites of synthesis of TGF-beta 1 and IGF-II. Tissues from 50, 70, 90, 110-day-old pig fetuses and 7-day-old postnatal pigs were Bouin's fixed, paraffin embedded and hybridized with biotin labelled cDNA probes. The expression of TGF-beta 1 messenger RNA was detectable primarily in the dermis, hair follicle fat lobule, outer and inner SQ areas at all ages. Cells adjacent to adipocyte clusters and some small adipocytes were positive for TGF-beta 1. There was no positive hybridization of TGF-beta 1 probes in the developing muscle below the SQ. The expression of IGF-II was evident in the developing muscle below the SQ at 50 d and 70 d, and could be detected in the outer and inner SQ at 70 d. Much lower levels of IGF-II expression were observed in 90 and 110 d fetuses, but an increase in IGF-II expression was evident in the muscle of 7d postnatal pigs. Our results suggest that paracrine and autocrine regulatory systems may be operative for developing adipocytes (TGF-beta 1) and muscle (IGF-II), with specific areas and times of TGF-beta 1 and IGF-II expression being evident in developing pig SQ tissue.


Relation between brain and body growth in allied rats. Cranial volumes were measured from museum specimens of wild-caught and laboratory-born Allied rats from eastern Australia. The relation of these volumes to body weight and body length, and also to age at death in the laboratory-reared sample, was determined. Growth of both brain and body was rapid during the first three postnatal months and slowed markedly over the next month, but appeared to continue at a very slow rate throughout life. In particular, the major surge in brain growth occurred in the first three postnatal weeks. Modified Gompertzian growth functions describe the pattern of growth quite well, though the nature of the data precluded highly sensitive fits. Three features were clear: 1) the rate of slowing of growth was about the same for all variables, 2) growth appeared to continue throughout the life of the animal, and 3) the trajectory of brain growth led that of body growth by about four days. The pattern of growth in Allied rats is similar to that of laboratory rats and probably to those in other murids.


Effects of surgical decapitation and chicken growth hormone (cGH) replacement therapy on chick embryo growth. The effects of decapitation and chicken growth hormone (cGH) replacement therapy on chick embryo growth has been investigated. Removal of the prosencephalon at 33-38 hrs (1.38 to 1.58 Days) of incubation decreased body (torso) and liver weights as well as skeletal growth as indicated by tibial length. A single pituitary gland transplanted onto the chorioallantoic membrane (CAM) partially restored torso growth and completely reversed the increase in body water content which characterizes decapitated embryos. Replacement therapy with cGH did not influence body weight but did, on Day 16.5 of incubation, increase tibial length and liver DNA content and concentration. These latter findings suggest that there may be limited hypothalamoadenohypophyseal (GH) axis function in the chick embryo. The effects of decapitation on torso growth are also discussed in conjunction with decapitation effects on albumen swallowing (absorption) and yolk absorption.


Sexual cranial dimorphism in malnourished rats treated with growth hormone. One hundred and sixty two Holtzman rats of both sexes were malnourished during suckling and post-weaning periods. Some of them received periodic injections of growth hormone. After sampling, at 56 days of age, skulls were cleaned and measured. Differences within and between sexes were estimated by Mahalanobis D2 distances. Normal cranial differentiation between sexes (SCD) was decreased by malnutrition and restored by growth hormone treatment. The effect of the growth hormone on skull size was larger in malnourished males than females. This differential increment between sexes explains how growth hormone acted on the restoration of SCD.


Psychotic versus nonpsychotic misdemeanants in a large county jail: an analysis of pretrial treatment by the legal system. There are significant numbers of mentally ill men and women in jail and the level of their psychopathology is often serious. Once in jail, the psychotic individual is subjected to conditions conducive to further decompensation and higher suicide rates. If this is the case, the duration of confinement--that is, the duration of exposure to this toxic environment--is not trivial. Of further concern, from the standpoint of due process, would be the duration of confinement prior to any determination of guilt or innocence. Therefore, it makes sense to examine what happens to jailed psychotic individuals as they wait for trial. Our experience suggested that pretrial jail time, even for minor offenses, is lengthy. The central hypothesis of our study, then, was that psychotic men, charged with misdemeanor offenses, would be incarcerated for significantly longer periods of time, prior to trial, than their nonpsychotic fellows. Descriptive data was also collected.


Porokeratosis in immunosuppressed and nonimmunosuppressed patients. Porokeratosis is an uncommon, inherited, autosomally dominant disorder. In the last decade association of porokeratosis and immunosuppression has been observed. In this study we carried out a comparative study between immunosuppressed and nonimmunosuppressed porokeratosis cases. We found that 9 out of 20 cases of porokeratosis were associated with organ transplantation/immunosuppression. Clinicopathologic study revealed that the pattern of disease is alike both in immunosuppressed and nonimmunosuppressed patients. Our observations indicate that immune modulation could be a factor in the genesis of porokeratosis.


Candida albicans--saprophyte or pathogen? Skin scrapings taken from toe spaces of 200 healthy volunteers and from toe webs and groins of 150 pediatric patients were cultured for Candida albicans using the serum germ-tube test. The results showed that Candida albicans can be isolated in about 15% of normal toe spaces and 14% of children with normal groins. Although Candida albicans can be found in various grades of athlete's foot and also in some abnormal groins, we believe that it is not necessarily responsible for these conditions and is often present at these sites only as a saprophyte.


Hemostasis and platelet aggregation in purpuric pigmented angiodermatitis eruptions. Ten patients with chronic purpuric and pigmented angiodermatitis in the extremities and two patients with acute and disseminated eczematoid-like purpura angiodermatitis were studied with current hemostasis parameters: (1) platelet aggregation, (2) platelet circulating aggregates, (3) clotting factor measurements and high molecular weight kininogen (HMWK) in their coagulation fraction. The results showed: (1) reactional thrombocytosis with morphologic changes; (2) increased levels of platelet circulating aggregates; (3) increased response of platelet aggregation to different agonists, especially at very low doses, and also when we used washed platelets resuspended in normal plasma; (4) delayed activation of the contact system; (5) decrease of the activity of the fibrinolysis activators; and (6) diminished function activity of the HMWK coagulation fraction. As a physiopathogenic hypothesis in these patients, there is a cutaneous pathology that could be entailed to these hematologic alterations of the platelet-HMWK-endothelial cells-kinins-coagulation-fibrinolysis system.


Treatment of female androgenetic alopecia with minoxidil 2%. The safety and efficacy of minoxidil 2% for the treatment of female androgenetic alopecia was assessed in a 32-week double-blind placebo-controlled trial. Thirty-three women aged 22 to 44 years with hair loss classified as Ludwig's grade I or II were enrolled, and 28 completed the trial. Before the administration of treatment, mean nonvellus hair counts were taken within a 1-cm2 target area of the scalp. For the 15 patients in the minoxidil group, the mean count was 169 hairs compared with 161 hairs for the 13 patients in the placebo group. At the completion of the trial, the patients treated with minoxidil 2% had a mean nonvellus hair count of 195 hairs versus a mean hair count of 177 for patients in the placebo group; 60% (9) of the patients in the minoxidil group showed minimal to moderate hair growth compared with 46% (6) of the patients in the placebo group. No serious side effects were encountered during this study, nor any significant changes in safety parameters. There were no dropouts due to medical events related to minoxidil 2%.


Lepromatous leprosy treated with recombinant interferon gamma: cutaneous histologic changes. We report on the histologic changes occurring in single cutaneous lesions, from six active lepromatous patients, 1 week following the administration of three daily intradermal injections, 35 micrograms each, of recombinant interferon gamma (rIFN-gamma). Except for a strong induration at the injection site, rIFN-gamma produced no adverse systemic reactions and was able to promote a remarkable influx of T-lymphocytes, mononuclear phagocytes with large nuclei, nonvacuolated cytoplasm, and reduced lysozyme reactivity. Furthermore, despite no clear-cut reduction of mycobacterial dermal burden, bacilli showed a clear increase in the granular appearance. Present findings provide a basis for further elucidation of rIFN-gamma as an additional tool for leprosy treatment.


Pattern of skin diseases at the National Skin Centre (Singapore) from 1989-1990. At the National Skin Centre, 74,589 new attendances were seen from 1989 to 1990. The M:F ratio was 1:1. The majority of the patients belonged to the 20-39 year age groups (40%). Frequencies of psoriasis (20.4%) and alopecia (17.2%) were higher among Indians; exfoliative dermatitis was higher among Malays (19.72%); and insect bites were higher among Chinese (87%) [P less than 0.05] compared with ethnic distribution (9.9%, 7.6%, and 77.2% respectively) of NSC patient population. Dermatitis (34.2%) and acne (10.9%) were the most common skin disorders seen. The more common dermatoses seen in 1989/90 differ slightly from those reported in 1950s and 1980s; however, the frequencies of contact dermatitis, fungal infection, and insect bite reactions of 5.8%, 10.9%, and 7.6%, respectively, in 1980 have decreased to 4.7%, 5.4%, and 2.3%, respectively, in 1989/90. There was no seasonal variation in the frequency of various dermatoses except for psoriasis, which was more prevalent during the first quarters of 1989 and 1990. Our results showed that the pattern of skin diseases in Singapore is slowly approximating that of developed countries. The changes in the pattern of skin diseases are probably due to improved economic status, better education and hygiene, ready availability of dermatology services, as well as changes in occupational and environmental contactants over the last decade.


Incidence of skin disease in Cuzco, Peru. In the nations of the developing world, the incidence of skin disease is especially affected by geography. While most studies focus on the tropics, this report records the pattern of skin diseases encountered in a South American mountain city. Among 1277 patients examined, the noninfectious dermatoses predominated.


Chronic cutaneous leishmaniasis: Leishmania parasites in blood. Two patients with chronic cutaneous leishmaniasis had positive blood cultures. The diagnosis was established by the clinical picture, skin biopsy, and culture for Leishmania major and tropica.


Cutaneous leishmaniasis in Riyadh region: four-year study of the epidemiologic and clinical features. A retrospective study of 11,802 patient records with cutaneous leishmaniasis in Riyadh region was conducted during the period 1987 to 1990. The following findings resulted from the study. The incidence rate declined from 244.2 to 106.5 per 100,000 population. The infection was mainly among non-Saudi men in their working years. The Saudis represented 33% of the total number of patients. The Saudi patients were mainly young, below 15 years of age, with almost equal men/women distribution. The non-Saudis were found to have more multiple lesions; 65% of them had three or more lesions compared with 10% in Saudis. The lesions were mainly on the exposed parts of the body such as the face (20%), neck (3.3%), upper limbs (23.3%), and lower limbs (15%). Agricultural areas such as Riyadh vicinity, Al-Kharj, Shagraa, and Al-Koweeya showed consistently the highest foci of infections. The infections were highest in winter and lowest in summer.


Diffuse cutaneous leishmaniasis with atypical aspects. A 16-year-old man had long-standing diffuse cutaneous leishmaniasis with the following characteristics: diffuse infiltrated lesions rich in amastigotes, absence of mucosal involvement, and lack of parasite-specific cell-mediated immune response. In situ identification of Leishmania mexicana amazonensis was achieved by the use of monoclonal antibodies. Clinically, as an atypical finding there was deep and extensive ulceration in the lower limbs. Histologically, an atypical characteristic was the presence of a high number of eosinophils in the infiltrate predominantly in the ulcerated lesion. Ultrastructurally, parasitized and lysed eosinophils with dispersion of their granules were seen in the vicinity of parasitized or lysed macrophages.


Behçet's disease and surgical intervention. Behçet's Disease (BD) is a systemic disorder with an unknown etiopathogenesis. The need for clinical criteria in the establishment of diagnosis is of great importance. We present the case of a 27-year-old man with BD, who had a surgical operation during the active period of his disease and experienced subsequent complications. Cutaneous hyper-reactivity response to minor cutaneous trauma--the pathergy phenomenon--is found in most patients with BD. Theoretically, major traumas may lead to major reactions in the skin or any of the organs. In practice, we observed that while there was a severe inflammatory reaction--histopathologically a superficial perivascular dermatitis--which developed at the incision site, the systemic symptoms of the disease increased in spite of intensive treatment of the condition.


Pyoderma gangrenosum: associations revisited. Fourteen cases of pyoderma gangrenosum were seen over a period of 24 years at the Hull Royal Infirmary Dermatology Department. Several associated conditions were found. Seven cases were associated with rheumatoid arthritis of which five were sero-positive, including one with Felty's syndrome. One case was associated with both ulcerative colitis and psoriasis; one with polycythemia rubra vera; two patients had diverticular disease including one who also had rheumatoid arthritis; one had positive syphilis serology. In three cases there was no significant associated disease identified. Ten out of the fourteen cases were women, indicating a female preponderance by a ratio of about 2F:1M; a figure similar to that stated by Seitzinger. The age of presentation ranged from 30 to 80 years.


Hair follicle nevus.

Hair follicle nevus. Four cases of hair follicle nevi are described. Hair follicle nevus is an extremely rare hamartoma occurring on the face, which has had no clear histopathologic definition until now. A short review of the clinicopathologic features of this disease is presented.


Acute adult T-cell leukemia/lymphoma presenting with florid cutaneous disease. Adult T-cell leukemia/lymphoma (ATLL) is characterized by cutaneous disease, hypercalcemia, associated HTLV-I infection, and a fulminant course refractory to therapy. A patient with acute ATLL is described, and the natural history of ATLL is reviewed.


Treatment of pyoderma gangrenosum with clofazimine. We report a case of pyoderma gangrenosum in a 80-year-old woman suffering from ulcerative colitis and treated with clofazimine. Significant improvement was evident within 5 days following commencement of therapy, complete healing occurred after only 4 weeks of treatment.


Pyoderma gangrenosum treated with hyperbaric oxygen therapy. The management of pyoderma gangrenosum often requires systemic drug therapy, such as corticosteroids, sulfones, or immunosuppressants, either alone or in combination. Inconsistent response to therapy is a source of frustration to both patient and physician. Several reports in the literature document the successful treatment of pyoderma gangrenosum with hyperbaric oxygen therapy. In our patient, a woman with severe rheumatoid arthritis and diabetes mellitus, hyperbaric oxygen therapy not only promoted healing of pyoderma gangrenosum but permitted reduction of systemic corticosteroids.


New approaches to assess topical corticosteroid bioequivalence: pharmacokinetic evaluation. An ideal method for measuring the bioavailability of topical corticosteroids should be simple, accurate, and adaptable to a variety of settings and should not require extensive special training to perform. Drug uptake into the stratum corneum, measured by tapestripping, is correlated with the pharmacodynamic response of skin blanching, observed in the vasoconstrictor assay. Differences in stratum corneum drug uptake can be objectively quantitated as a function of time, occlusion, dose applied, and vehicle. Tapestripping measurements are reproducible within individual subjects, but large interindividual variabilities may exist. The chromameter, a new technology, objectively quantitates color numerically and can be used to measure skin blanching as part of the pharmacodynamic response to topical corticosteroids. The chromameter offers an easy, objective method with which to quantitate the pharmacodynamic response of topical corticosteroids. Both methods allow a more mechanistic approach than currently used methods to investigate topical drug pharmacokinetics and pharmacodynamics.


Bioequivalence of topical corticosteroids: a regulatory perspective. After reviewing the history of generic drug substitution policy in the United States, this paper discusses issues of equivalence as they apply to topical drug products. Documentation of bioequivalence of topical products has been problematic, and current methods are being re-evaluated by the Food and Drug Administration. The FDA is currently evaluating various extensions of the basic methodology of the Stoughton-McKenzie vasoconstrictor assay, in order to develop a more comprehensive pharmacodynamic methodology for documenting topical drug bioequivalence. A modern pharmacodynamic model is described, based on nonlinear dose-response relationship, a baseline effect, and a maximum or plateau effect. The Agency's goal is a bioequivalent methodology that will be simple, readily performed, and based on more objective methods of measuring the vasoconstrictor response.


Issues in measuring percutaneous absorption of topical corticosteroids. Studies that examine the pharmacokinetics of topical drugs at their site of action in the skin have been difficult to perform and, therefore, limited in number. In the early years of topical drug pharmacokinetic research, investigators had to rely on the measurement of less direct indicators of drug throughput such as blood levels and urinary excretion. Today, advances in theory are impelling pharmacokinetic research in new directions, including the measurement of drug availability in tissue compartments within the skin. This research will lead to greater precision in pharmacokinetic measurement and greater relevance of these measurements to the therapeutic efficacy of topical corticosteroids in cutaneous disease states.


The vasoconstrictor assay in bioequivalence testing: practical concerns and recent developments. The vasoconstrictor assay, when properly performed, is a highly reliable method to determine bioequivalence of generic formulations. Recent research has resolved some of the remaining questions concerning the practical application of the assay. Significant vehicle-related differences have been observed between the potency of different, supposedly equivalent formulations now on the market. Large differences in concentrations of the active agent in similar vehicles usually have not resulted in corresponding differences in vasoconstrictor assay results. Finally, the time course of drug effects may differ among highly potent and less potent corticosteroids. In general, the higher the potency of the topical corticosteroid, the earlier the maximal effect is observed. This finding suggests that short application of highly potent agents might minimize systemic absorption without sacrificing efficacy.


Bioequivalence studies of topical preparations: statistical considerations. To be approved for marketing, a potential generic pharmaceutical product must demonstrate bioequivalence, that is, a rate and extent of absorption similar to those of the currently marketed ("innovator") product. For oral products, design and statistical analysis for studies conducted to determine whether two products are bioequivalent have become reasonably standardized; the design is crossover, and analysis is based on the two one-sided tests principle. The purpose of this overview is to consider whether the practices for oral products apply to topical products, and where different procedures may be required. The principles behind the practices for oral products are seen, largely, to carry over to topical products.


Topical corticosteroids: quality control considerations. A simple procedure is developed, which can be used as a quality control test. The method utilizes commercially available diffusion cell assembly, synthetic membrane, and an appropriate receptor phase. The amount of drug released over time is determined using an HPLC method. From this, the drug release rate, flux, microgram/cm2/min0.5 is calculated. This drug release rate can serve as a good quality control test to assure batch-to-batch uniformity.


Clinical trials of topical corticosteroids in psoriasis: correlations with the vasoconstrictor assay. It would be desirable to develop an alternative system to clinical studies to evaluate the potency of generic topical corticosteroids and of new formulations of existing innovator corticosteroids. The vasoconstrictor assay is a reliable method for testing potency; however, its results do not always agree with clinical studies. Psoriasis offers an ideal clinical model to evaluate corticoid potency because the ability to perform within-patient comparisons of the treatment of bilateral lesions permits meaningful comparisons with a relatively small sample size. The results of bilateral comparisons in psoriasis agreed with those of the vasoconstrictor assay in 20 of 23 comparisons of active agents and in numerous comparisons of active corticosteroids with a placebo. Eczematous dermatoses do not lend themselves well to bilateral paired comparison studies and therefore require parallel treatment studies with relatively large sample sizes to produce statistically significant comparisons.


Animal models for testing topical corticosteroid potency: a review and some suggested new approaches. Animal models allow for testing the potency of topical corticosteroids by measuring their effects on induced conditions that are analogous to human skin disease. Animal models can examine the anti-inflammatory, anti-allergic, antiproliferative, and atrophogenic effects of topical corticosteroids. These test models as they are currently applied are relatively imprecise; however, innovations using newly available histologic, autoradiographic, and biochemical techniques have great potential for precisely quantitating the effects of corticosteroids in animal model systems.


Human test models for bioequivalence of topical corticosteroids: a review. It would be useful to have a safe, reliable, reproducible, and inexpensive human test model to determine the potency of topical corticosteroids and the bioequivalence of generic agents. Existing human test systems include erythema or inflammation induced by irritants or other stimuli, experimentally induced cutaneous disease-like states, and bioassays in patients with psoriasis. None of these systems is currently reliable enough to warrant general use. Among the shortcomings of existing test systems are the difficulty of producing a uniform, steroid-responsive test condition, the requirement to use occlusion in several of the systems, and the lack of agreement among the results of different tests. Despite these shortcomings, some of the tests may prove useful in comparing innovator and generic topical corticosteroids and in screening the potency of new agents.


Smoking and lung cancer in China: combined analysis of eight case-control studies. Smoking is well established as a principal risk factor for lung cancer. The risk of lung cancer is about ten times higher in smokers in Western countries. In China, a number of epidemiological studies have investigated the association between lung cancer and smoking and in the present paper, a combined analysis of eight such case-control studies is described. The summary odds ratio (OR), calculated by the Mantel-Haenszel method, and attributable risk (AR) of lung cancer associated with smoking were calculated from the combined data which were obtained from a literature review. The eight case-control studies were conducted in Beijing, Shanghai, Shenyang, Nanjing, Harbin, Zhengzhou, Taiyuan, and Nanchang, yielding a total of 4081 lung cancer cases and 4338 controls. The summary OR of lung cancer associated with smoking was 2.17 (95% CI (confidence interval): 1.98-2.39). The OR were 3.09 (95% CI: 2.61-3.66) for males and 2.30 (95% CI: 1.96-2.69) for females. The AR were 38.2% for both sexes, 56.7% for males and 25.5% for females. Risks of 1.00, 1.03, 2.04, and 3.33 showed a dose-response relationship between lung cancer and number of cigarettes smoked per day. There were also significant dose-response relationships of lung cancer with duration of smoking (OR = 1.00, 1.02, 2.66), and age at start of smoking (OR = 1.00, 3.30, 2.36, 1.18). The OR and AR of lung cancer associated with smoking in China were much lower than those reported in Western countries and the possible reasons for this are discussed.


Occupational and environmental hazards associated with lung cancer. In a hospital-based case-control study 194 lung cancer cases, 194 hospital controls, and 194 population controls were interviewed for their smoking, occupational, and residential history by trained interviewers, using a standardized questionnaire. In order to include many different environmental exposures, case ascertainment took place in seven different hospitals with catchment areas ranging from rural to highly industrialized. Lung cancer risk strongly increases with cumulative cigarette dose, reaching an odds ratio (OR) of 16.19 (95% confidence limits (CL): 5.10, 51.33) for male smokers of more than 40 pack-years and an OR of 19.99 (95% CL: 4.98, 80.24) for female smokers of more than 20 pack-years. For the quantification of occupational exposure to known carcinogens of the lung a novel approach was developed which accumulates exposure information obtained by supplemental questionnaires through an automatic procedure. The OR for the highest exposure group in males was 2.7 (95% CL: 1.23, 5.78). Significantly increased risks were observed in the metal industry, particularly in smelter and foundry workers (OR 4.8, 95% CL: 1.15, 20.16) and in turners (OR 2.2, 95% CL: 1.05, 4.75). In the construction industry the risks were particularly high in road construction workers (OR 3.7, 95% CL: 1.06, 13.20) and in unskilled construction workers (OR 2.7, 95% CL: 1.24, 5.76). The risks in these occupational groups increased with duration and with latency. Quantification of air pollution was done on a county basis by time period. An index based on emission data for sulphur dioxide was compared to a semiquantitative index, which included additional information on ambient air pollution. After adjustment for smoking and occupational exposures an OR of 1.01 (95% CL: 0.53, 1.91) for an emission index and of 1.16 (95% CL: 0.64, 2.13) for a semiquantitative index was obtained.


Relationship of blood prolactin levels and the risk of subsequent breast cancer. Between 1968 and 1976 a total of 5162 women volunteers were enrolled into a prospective study conducted on the Island of Guernsey. Up to February 1990 145 women subsequently developed breast cancer. Blood samples were taken at the time of enrollment and prolactin levels were known for 85% of the volunteers. In calculating the relationship between blood prolactin levels and subsequent breast cancer risk, women were excluded if they had a hysterectomy or an oophorectomy or had cancer at any site before enrollment. The final analysis was based on 2596 premenopausal and 1180 naturally postmenopausal women and, of these respectively, there were 71 and 40 volunteers who subsequently developed breast cancer. The total follow-up for these two groups was 49,941 and 22,360 woman-years, respectively. In assessing the relationship between blood prolactin levels and risk of subsequent breast cancer the cohort was divided into quintiles according to prolactin concentration and relative risks (RR) were estimated. In calculating these values possible confounding by age at entry, age at menarche, parity, age at first birth, years since menopause, body build, history of benign breast disease and family history of breast cancer were taken into consideration. There was no significant relation between risk of breast cancer and prolactin in either pre- or postmenopausal women. Hence prolactin appears not to be an important determinant of breast cancer risk.


Misclassification bias related to definition of menopausal status in case-control studies of breast cancer. It is often assumed, but has not been consistently observed, that some characteristics of reproductive history are specifically related to breast cancer of pre- or postmenopausal onset. To determine whether inconsistent reports may be due to differences in definition of menopause, we computed the relative odds (RO) of breast cancer for nulliparity, age at first live birth, family history of breast cancer and prior history of benign breast disease, separately in pre- and postmenopausal women, using seven different definitions of menopause. Results show that (i) relative odds of breast cancer and their confidence intervals may vary according to definitions of menopause; (ii) age-based definitions of menopause are associated with moderate differential misclassification bias between cases and controls; (iii) nulliparity, late age at first birth and family history of breast cancer seem to be specific risk factors for pre- but not postmenopausal breast cancer when cutoff for menopausal status is 10 years or more after last menses; and (iv) when information on menstrual history is not available, 50 years of age may be the best proxy for all menses-based definitions of menopause. We conclude that inconsistent findings on the effect of menopausal status in the association of breast cancer with some reproductive factors are partly due to statistical imprecision and differential misclassification bias associated with different age-based or menses-based definitions of menopause. Researchers should either test whether their conclusions hold using several definitions of menopause or give a biological rationale for the choice of a given definition of menopause.


Skinfold thickness and cardiovascular risk factors in American and Japanese telephone company executives. Data from a cross-sectional study of cardiovascular disease risk factors in 962 US and 827 Japanese male telephone company executives were used to determine the associations of skinfold thickness measurements (abdominal, subscapular, triceps, ulnar) with blood pressure, blood glucose, serum cholesterol, and serum triglycerides. These associations were assessed within each group of executives and were compared between the groups. Most skinfolds showed association with risk factors in univariate regression. After adjusting for age and body mass index, the abdominal skinfold continued to be significantly associated with blood pressure and triglycerides in both groups, while the subscapular skinfold showed associations only with triglycerides. After adjustment, the peripheral skinfolds showed no association with risk factors in the US men, however, in the Japanese men the ulnar skinfold continued to be associated with blood pressure. These findings suggest that abdominal and ulnar skinfold measurement may be useful in adjusting for the effect of obesity on coronary heart disease risk in epidemiological studies.


Are race differences in the prevalence of hypertension explained by body mass and fat distribution? A survey in a biracial population. Body mass and body fat distribution are important considerations in the study of hypertension. However, few studies have investigated the relationships with regards to race differences in elevated arterial pressure. A population-based sample of black and white adults was assessed by interview and physical measurement. The prevalence of hypertension (defined as 140/90 mmHg and/or medically treated) was disproportionately higher among blacks than whites. In addition, blacks had a higher prevalence of the more severe hypertension (160/95 mmHg) and hypertension with higher prevalence at earlier ages than whites. Black females had a significantly higher distribution of body mass index (BMI) than white females, while no difference was found in the distributions of males. White males had a higher distribution of waist to hip ratio (WHR) than black males, while black females had the higher values compared to white females. The prevalence of hypertension increased with BMI and WHR. Blacks maintained higher rates of hypertension after controlling for BMI and WHR, however, the margin of difference diminished when BMI and WHR was considered together. The black-white difference in hypertension was not completely explained by BMI and WHR. In addition, the strength of the association of hypertension and body size was different for blacks and whites which suggests possible differences in the mechanisms regulating blood pressure.


Blood pressure levels of Zambian rural adolescents and their relationship to age, sex, weight, height and three weight-for-height indices. A study of blood pressure levels of 372 rural Zambian schoolchildren age 7-16 years showed that blood pressure increases with age. The association between age and blood pressure is decreased when growth is controlled for in the analysis. Girls tended to have either the same or slightly higher mean blood pressure levels at all ages than boys. The main determinants of blood pressure in the children were age, height and weight. Mean systolic blood pressure (SBP) values of the children were lower than those for Nigerian, American and worldwide adolescents of comparable age, whereas mean diastolic blood pressure values were similar to those of American and worldwide adolescents of comparable age. The associations between blood pressure and the three indices commonly used to measure relative obesity, i.e. weight-for-length, weight/height2 and weight/height,3 were only significant for weight-for-length after adjusting for height, suggesting that the other two indices may not be appropriate in studies focussed on children and should be applied with caution. The nonsignificant associations observed between blood pressure and the other two weight-for-height indices may be attributed to the almost nonexistence of obesity in this sample of children.


Serum sialic acid concentration predicts both coronary heart disease and stroke mortality: multivariate analysis including 54,385 men and women during 20.5 years follow-up. To investigate the nature of the relationship between serum sialic acid concentration and cardiovascular mortality, the risks for coronary heart disease (CHD) and stroke were assessed separately in 26,693 men and 27,692 women followed during 20.5 years. Diastolic blood pressure, total cholesterol and body mass index were used as covariates in a person-year-based Poisson model. Relative risks for CHD mortality associated with the highest sialic acid quartile was 1.76 (95% confidence interval (CI): 1.58-1.96) in men and 1.94 (95% CI: 1.61-2.34) in women. Corresponding figures for stroke were 1.62 (95% CI: 1.26-2.09) and 1.68 (95% CI: 1.28-2.21) respectively. No significant patterns related to the age at entry was observed. For both genders, and both endpoints, diastolic blood pressure was associated with higher relative risk than sialic acid, and body mass index and serum total cholesterol were less predictive. Serum sialic acid concentration predicts both death from CHD and stroke in men and women independent of age. The biological foundation of this finding remains unclear.


Monitoring the incidence of myocardial infarctions: applications of capture-mark-recapture technology. It is critical to monitor the incidence of myocardial infarction. Typically, death certificates have been used as a proxy for incidence, however, these have been found to be crude as they lag behind changes in incidence. In the last decade several myocardial infarction registries have been established, however, these registries are still too limited in geographical spread to assess either national or global trends of heart attack. Here we suggest that employing an alternate approach, that of capture-mark-recapture, would be helpful to provide accurate monitoring both within and between countries. This method would complement existing registries by providing a simple and inexpensive means to provide accurate heart attack data across broad geographical areas and time.


Risk factors for preterm and term low birthweight in Ahmedabad, India. To identify and quantify risk factors for preterm and term low birthweight (LBW) we conducted a hospital-based case-control study, linked with a population survey in Ahmedabad, India. The case-control study of 673 term LBW, 644 preterm LBW cases and 1465 controls showed that low maternal weight, poor obstetric history, lack of antenatal care, clinical anaemia and hypertension were significant independent risk factors for both term and preterm LBW. Short interpregnancy interval was associated with an increased risk of preterm LBW birth while primiparous women had increased risk of term LBW. Muslim women were at a reduced risk of term LBW, but other socioeconomic factors did not remain significant after adjusting for these more proximate factors. Estimates of the prevalence of risk factors from the population survey was used to calculate attributable risk. This analysis suggested that a substantial proportion of term and preterm LBW births may be averted by improving maternal nutritional status, anaemia and antenatal care.


A case-control study of paternal smoking and birth defects. Although the influence of paternal smoking on birth defects is of great public interest, epidemiological evidence concerning this potential relationship is extremely limited. A stratified random sample of 29 hospitals in the Shanghai Municipality, China, was used to select 1012 birth defects cases and controls. Mothers of the cases and controls were interviewed in the hospitals from October 1986 to September 1987. A modest relationship between paternal smoking and overall birth defects in offspring was identified [odds ratio (OR) = 1.21, 95% confidence interval (CI): 1.01-1.45]. More markedly elevated risks were identified for anencephalus (OR = 2.1), spina bifida (OR = 1.9), pigmentary anomalies of the skin (OR = 3.3) and varus/valgus deformities of the feet (OR = 1.8). Our analysis also shows that paternal smoking is more likely to be associated with multiple rather than isolated malformations. A paternally-mediated effect of smoking on birth defects is suggested and further studies are encouraged.


Cigarette smoking in pregnancy and fetal growth. Does the type of tobacco play a role? The effect of nicotine content of cigarettes on fetal growth was studied. From April 1985 to April 1987, 86% of all pregnant women in two well-defined geographical areas responded to a questionnaire on social conditions and lifestyle factors in pregnancy. After excluding multiple births and women who gave birth after elective caesarean section, 10,485 pregnant women were available for the study. Results showed that not only smoking, but also nicotine content in cigarettes was related to reduced fetal growth as measured by birthweight, birth length, and head circumference. The timing of smoking during pregnancy played a role. Smoking before pregnancy or smoking early in pregnancy was not related to fetal growth, nor were the partners' smoking habits. The study corroborates the hypothesis that smoking reduces fetal growth and points to nicotine as one of the potential causal factors.


Perinatal 'TORCH' infections identified by serology: correlation with abnormalities in the children through 7 years of age. A matched case-control methodology was used to assess the risk for a wide range of abnormalities in children associated with serological evidence for 'TORCH' infections in the mothers. Specimens were selected from the large bank of sera from the approximately 54,000 pregnant women who participated in the Collaborative Perinatal Project. There was no clear association between any of the antigens studied and any specific damage to the child. These 'negative' findings are consistent with the absence of frequent significant effects due to these agents in the second and third trimesters of pregnancy.


Cigarette smoking and sick leave in an industrial population in Shanghai, China. A study of cigarette smoking and sick leave was conducted at a large petrochemical complex in Shanghai, China in 1988. Among a random sample of 1856 men the smoking prevalence was 80% with the highest rate (84%) occurring in the age group 25-34 years. Only 53% of smokers and 76% of nonsmokers said they believed smoking was harmful to health and knowledge of which diseases were associated with smoking was poor. Retrospective data were also collected on sick leave in 1986 and 1987. In 1986 13% of men took sick leave and in 1987 12%; the mean duration of sick leave was 3 days per year. In 1986 the odds ratios (OR) for taking sick leave were 2.37 for heavy smokers and 1.45 for light smokers compared to unity for nonsmokers; the corresponding OR for 1987 were 1.70 and 1.28 for heavy and light smokers compared with nonsmokers. Smoking was positively associated with sick leave even after adjustment for age, consumption of alcohol and exposure to chemicals; OR = 1.56 (95% confidence interval (Cl): 1.06-2.31) in 1986 and OR = 1.32 (95% Cl: 0.90-1.95) in 1987. Demonstration of this association even in a young population with low sick leave rates illustrates yet again the adverse effects of smoking on health and the urgent need to reduce the very high prevalence of smoking in China.


Smoking habits and attitudes of medical students towards smoking and antismoking campaigns in nine Asian countries. The Tobacco and Health Committee of the International Union Against Tuberculosis and Lung Diseases. As part of a world survey of the habits, knowledge and attitudes of medical students regarding tobacco we report a study in 15 medical schools from nine Asian countries. Some 1646 first year and 1587 final year students were included, of whom 59% were male. The prevalence of daily smoking in males was 4% in first year and 11% in final year; of occasional smoking 18% and 24% respectively, both with considerable variations between countries. The rates were very low in women. Male exsmokers varied from 3% to 24% in different centres. Overall, 33% of smokers had made a serious attempt to quit; 44% expected to have succeeded within 5 years. Over 80% of non- or exsmokers, but only 60% of smokers, thought smoking was harmful to health. There was gross underestimation of tobacco's causal role in a number of important diseases, e.g. coronary artery disease, peripheral vascular disease, emphysema, bladder cancer and neonatal mortality. There were notable defects both in training and in motivation to counsel smoking patients. There was only partial knowledge of legislative and other measures to discourage smoking, e.g. only 44% of final year students (26% of smokers) thought increased taxation an important measure. In knowledge and attitudes there was little difference between the sexes, but in most aspects smokers had notably lower scores.


The descriptive epidemiology of a sedentary lifestyle in adult Australians. Regular exercise is important for the maintenance of good health, but many people do very little exercise. There are public health concerns about activating the sedentary and, from an epidemiological measurement perspective, there are advantages in assessing physical inactivity. Using pooled data from 17,053 participants in Australian population surveys, we identified 5078 people (29.7%) who could be classified as sedentary in their recreational exercise habits. Logistic regression analyses found the inactive to be more likely to be older, less well educated, and to have lower incomes. The main reasons given for not exercising were no time (33%), being physically unable (23%), and not wanting to exercise (13%): these were more likely to be reported by those who were older, and who had lower incomes; the only exception was that being 55 years or older was not associated with having less time. Women were more likely to report being physically unable to exercise. Lower income was associated with being physically unable, and with not wanting to exercise. Those with children, while wanting to exercise, were more likely to report having no time. The greatest health benefits will result from the sedentary becoming more active, and inexpensive and convenient activities such as walking need to be emphasized.


Low sex ratios of births in areas at risk from air pollution from incinerators, as shown by geographical analysis and 3-dimensional mapping. Previous research in environmental and occupational health has suggested that fluctuations in the sex ratios of births might provide a useful early warning to the possible health effects of toxins or other stresses in the environment. To examine further this hypothesis, we investigated the sex ratios of births in an area in central Scotland which contained two incineration plants. Analyses of the sex ratios, at various levels of geographical detail and using 3-dimensional mapping techniques, in the residential areas at risk from airborne pollution from these incinerators showed locations with statistically significant excesses of female births.


Life table analysis of infant mortality and feto-infant mortality distributed on causes of death in Denmark 1983-1987. The survival function of 263,322 singletons of the 1983-1987 Danish birth cohorts (262,159 liveborn and 1163 stillborn babies) with mortality distributed on functional groups of underlying causes of death is presented in two graphic forms on the basis of Kaplan-Meier estimates. About half of all first-day deaths in liveborn babies occurred during the first 4 hours. More than half of all first-week deaths happened during the first day. More than half of all deaths from 31 weeks to 76 weeks after the first day of the last menstrual period (LMP) were either fetal deaths prior to the onset of labour unexplained by fetal factors or unexplained sudden infant death syndrome (SIDS) deaths. Graphic presentation of feto-infant mortality distributed on functional cause-of-death groups improved the expression of the relative contribution and timing of the different causes of deaths. Despite a high autopsy rate and a uniform coding practice the distribution on causes of deaths from register data should be interpreted with caution. Full use of the feto-infant approach is only achieved with data which include late abortions. Thus the feto-infant approach is of special interest in countries which have registers of live births and fetal deaths from week 22 of gestation or earlier. The integration of the life table approach and analysis of underlying causes of deaths should be further explored as a way of utilizing vital statistic databases for the evaluation of perinatal care.


Region of birth and mortality of blacks in the United States. Analysis of black American death rates by region of birth and region of residence showed that southern-born blacks had the highest mortality rates and western-born blacks the lowest mortality rates. Blacks born in the northeast, midwest, and outside the US had rates intermediate between southern and western-born black rates. Blacks born in one region and who died in another had age-specific and age-adjusted mortality rates similar to their region of birth rather than their region of residence.


The contribution of unemployment to socioeconomic health differences. Unemployment and socioeconomic status (SES) are both related to mortality and health inequality or differences. The main purpose of this study is to assess the contribution of these factors to health status. Data have been analysed from over 500 employed and 500 unemployed men, 30-50 years old, in two highly industrialized areas of the Netherlands. Three scales of self-reported health were used: somatic complaints, depressive complaints and chronic diseases. Experimentally, four SES measures were tested separately: education, occupation and household income as single measures, and a composite score constructed from the weighted sum of these measures. Results show a clear independent influence of SES as well as unemployment on health differences, when indicated by occupation or education. Household income appears to influence the results, the implications of which are discussed. Including the longitudinal follow-up there are three measurements over time. These data were used to test a homogenizing hypothesis, questioning processes that might indicate the existence of one unemployed (under) class. This hypothesis was rejected. Finally the data indicated a small contribution of health selection processes on the labour market.


Pets, allergy and respiratory symptoms in children. The relationship between pet ownership and respiratory allergy and symptoms was investigated in a population of 3344 Dutch children of 6-12 years old. Pet ownership was defined by the presence of cats, dogs, birds and/or rodents in the home. The reported prevalence of respiratory allergy and symptoms was lower among children of current pet owners than among children of parents who owned no pets. When past pet ownership was taken into account, however, a different picture emerged. The lowest prevalence of respiratory allergy and symptoms was found in children of current pet owners who had no pets in the past. The next lowest prevalence was found in children of current pet owners who had had pets in the past also. The next highest prevalence was found in children who never had pets in their life. The highest prevalence of reported pet allergy, chronic cough, wheeze, attacks of shortness of breath with wheezing, and doctor-diagnosed asthma was found in children who had pets in the past but not anymore. Past cat ownership especially was associated with a high prevalence of pet allergy and doctor-diagnosed asthma. Almost 2% of the population reported to never have owned pets for health reasons, and more than 12% reported removing pets from the home for health reasons in the past. These results show that selective avoidance and removal of pets leads to distortions of cross-sectional associations between pet ownership and respiratory allergy and disease among children.


Death certificate coding practices related to diabetes in European countries--the 'EURODIAB Subarea C' Study. The objective of this study was to compare and analyse coding practices for diabetes mortality data in nine European countries (Belgium, Republic of Ireland, France, Germany, Malta, The Netherlands, Northern Ireland, Scotland and Switzerland). In each country, a sample of 200 coded death certificates, which mentioned diabetes, was randomly sampled. All death certificates were recoded at the WHO Collaborating Centre for the Classification of Diseases in the French language. The results show wide differences between national coding and central coding. Discrepancies in the underlying cause of death existed at the 3-digit coding level for 26% of all death certificates and for 44% at the 4-digit level. Coding in Northern Ireland and Malta was characterized by a marked tendency to choose diabetes less frequently. In contrast, in The Netherlands and, to a lesser extent, in the Republic of Ireland and France, diabetes was more frequently selected as the underlying cause of death. Most of the differences concerned the coding of an association involving diabetes and circulatory system diseases. In some countries, these coding differences influence the reported level of diabetes mortality. For Northern Ireland and Malta, the number of certificates with diabetes as the underlying cause of death was more than doubled after central recoding and for The Netherlands, in contrast, it was almost halved. To explain the differences a number of factors are considered: a lack of information from the International Classification of Diseases (ICD), on the application of the coding rules, between-country differences in cause of death certification practices, a divergence of opinion about the causal role of diabetes when it is associated with other conditions, a lack of homogeneity between countries in data collection procedures.(ABSTRACT TRUNCATED AT 250 WORDS)


Risk of developing insulin-dependent diabetes mellitus (IDDM) before 35 years of age: indications of climatological determinants for age at onset. This study analyses data from two nationwide prospective diabetes registries now covering about 3400 cases from 19 million person-years of follow-up in the age group 0-34 years. The risk of developing insulin-dependent diabetes mellitus (IDDM) per 100,000 individuals before 15 years was 386 (95% confidence intervals (CI): 362-410) for boys and 391 (95% CI: 367-415) for girls and by 35 years 701 (95% CI: 671-731) for men and 562 (95% CI: 534-690) for women. The incidence rate showed a maximum for both boys and girls in early puberty. After pubertal years a sharp increase in the male to female incidence ratio of IDDM was notable. At 10-14 years it was 0.94, at 15-19 years 1.59 and at 20-24 years 2.08. A Cox regression model was used to analyse the effects on age at onset of sex, population density and climatological factors as measured by north-south area of residence and season at onset. The effect of sex was confirmed (P less than 0.001). A significant effect (P = 0.004) of season was shown when the four seasons were classified according to a four stage scale related to mean temperature. When dividing Sweden into 11 regions according to north-south gradient (Latitude 55 degrees, 56 degrees, 57 degrees, ..., 65 degrees) a significant effect (P = 0.038) was also found. However, no effects of population density or living near the coast versus in the interior were found. It is concluded that a large proportion of the young are at risk of developing this chronic disease.(ABSTRACT TRUNCATED AT 250 WORDS)


Motor disability in children in three birth cohorts. A systematic registration was carried out in 1985-1986 and 1989 in 14 French 'departments' in order to assess whether the prevalence rates of different components of motor disability (MD) in three different birth cohorts (1972, 1976 and 1981) had changed at a time when the preterm birth rate and neonatal mortality were decreasing and there was evidence of changing perinatal practice. A total of 1355 MD were registered amongst resident children born in 1972, 1976 and 1981 with a prevalence of 3.34 per 1000. The prevalence of the MD types due to different causes did not differ significantly amongst the three birth cohorts with the exception of an excess of hereditary and degenerative disease of the central nervous system (CNS) among children born in 1981. The prevalence of cerebral palsy (CP) remained stable in the three birth cohorts: it was 1.30, 1.06 and 1.08 per 1000 respectively, for children born in 1972, 1976 and 1981. The prevalence of pre- or perinatal-origin of other motor disabilities (OMD) and of CNS malformations did not differ amongst the three birth cohorts. The method of registration is discussed and the results are related to those of the French perinatal surveys performed in 1972, 1976 and 1981, which showed a decrease in preterm birthrate, an increase in perinatal care and a decrease in the mortality rate of high-risk infants.


Prevalence of childhood disability in a southern Indian city: independent effect of small differences in social status. A random sample of mothers living in two neighbourhoods of a southern Indian city were interviewed in order to determine the prevalence of serious disability in children 2-9 years old. These areas were selected because residents constitute either the lowest class or the next higher socioeconomic class (next-to-lowest class), with monthly incomes of US$ 10-15 and 32-42 respectively. A previously validated screening instrument was used with documented sensitivity of 100% and specificity of 95% when applied under similar conditions. Disability was found to be more common among children of the lowest class families (17.2%) when compared with the next-to-lowest class families (8.4%); with an odds ratio (OR) of 2.36 (95% confidence interval (CI): 1.08-3.64). Specific types of disability were examined and found to be consistently more prevalent in the lowest class. These results suggest that comparatively small differences in social status can be associated with important differences in health status.


Conjunctival impression cytology with transfer as a field-applicable indicator of vitamin A status for mass screening. The increasing importance of vitamin A deficiency in even its mild subclinical form underlines the need for a mass screening test. Clinical, biochemical and cytological methods of assessing vitamin A deficiency in a public health setting have been described and widely used. The cytological method shows promise because it enables early detection of vitamin A deficiency. However interpretation is problematic since histopathological changes are gradual with the progressive disappearance of goblet cells and appearance of enlarged epithelial cells. The reliability and validity of the impression cytology with transfer (ICT) test were assessed in order to produce a meaningful standard for this cytological method. The ICT test was performed in Senegal on 1451 children, in the course of two surveys conducted in 1989 and 1990 in rural areas. Reliability, estimated by Cohen's kappa test for evaluating intra-reader variability, and sensitivity were highest for the abnormal-normal classification (kappa = 0.91; 95% confidence interval (CI): 0.89-0.93; and sensitivity = 74%; 95% CI 66-82%). The ICT method is a cheap, noninvasive and easy test to perform in the field. This method is also reproducible and fairly sensitive according to the abnormal-normal classification. As illustrated by our proposed 50% cutoff of abnormal cytology calculated in relation to 5% of serum retinol values below 0.35 mumol/L criterion, ICT only requires a small sample for the assessment of the overall health of a community in contrast to xerophthalmia and blood vitamin A deficiency tests.


The male predominance in the incidence of infectious diseases in children: a postulated explanation for disparities in the literature. In children, a male predominance in the incidence of symptomatic disease has been reported for some infectious agents and not for others. Not only are the factors underlying these sex differences poorly understood, but it is also not clear why the differences are described only for selected infectious diseases. In this study of sex- and age-specific incidence of infectious diseases in children, a possible explanation for the inconsistencies in the literature was explored. The sex ratio in reported disease incidence in Israel during a period of about 20 years was examined for various viral and bacterial infections. In addition, an hypothetical mathematical model was developed which assumes increased susceptibility to infectious disease (such as in relative immune deficiency) in a proportion of males. In children aged under 4 years, a higher incidence among males was consistently observed for all diseases, and the sex ratio varied between 1.16 (95% confidence interval (CI): 1.13-1.18) for shigellosis to 1.98 (95% CI: 1.79-2.17) for viral meningitis. The highest ratios were associated with the diseases which tend to present asymptomatically most often, which is consistent with the predictions of the model. The male excess in symptomatic disease appears to be present for most infectious diseases and this should be taken into account in studies comparing observed disease incidence between groups with different sex ratios. The inconsistencies in reports on the excess male morbidity for infectious diseases may be due to variations in symptomatic to asymptomatic infection ratios.


Asymptomatic subjects at HIV diagnosis have prolonged survival as AIDS patients. The median AIDS survival for all AIDS patients was estimated as 11 months (95% confidence interval (Cl): 8-13 months). For the group of AIDS patients who were asymptomatic when HIV seropositivity was established, the median AIDS survival was 20 months (95% Cl: 13-23 months). For the group with symptomatic HIV infection or those who already had AIDS when HIV seropositivity was established, survival was estimated to 5 months (95% Cl: 1-15 months) and 4.5 months (95% Cl: 2-8 months), respectively. By using a Cox proportional hazard model it was found that being asymptomatic when HIV seropositivity was established or having Pneumocystis carinii pneumonia as the initial AIDS-related disease were associated with long AIDS survival. Being HIV infected by transfusion was associated with short survival. Long AIDS survival in the asymptomatic group may be explained by a positive selection of slow disease progressors. Differences in diagnostic routines may also cause systematic differences in the estimated AIDS survival.


The prevalence and regional distribution of antibodies against Chlamydia pneumoniae (strain TWAR) in Finland in 1958. The occurrence of nonavian 'ornithosis' was reported in Scandinavia at the end of the 1950s. In order to find out whether Chlamydia pneumoniae had been present in Finland, we examined the IgG antibody prevalence to C pneumoniae in samples representing the whole rural population of Finland in 1958. The total number of sera studied using micro-immunofluorescence was 2000. Trend-surface analysis was used to examine the regional patterns of antibody prevalence. C pneumoniae antibodies were present throughout the country. The mean antibody prevalence was 56% among adults and 27% among children. Thus the possible role of C pneumoniae in nonavian 'ornithosis' in Finland between 1958 and 1960 cannot be excluded.


Risk factor dynamics, mortality and life expectancy differences between eastern and western Finland: the Finnish Cohorts of the Seven Countries Study. Prior studies have not accounted for male mortality being higher in east than west Finland. Efforts to identify the mechanisms producing higher mortality in the east, due primarily to cardiovascular diseases (CVD), initially focused on a search for new risk factors. An alternate approach is to examine the assumptions of the analysis. This was investigated using a model which described (a) changes in risk factors over time, (b) dependency of risk factor effects on age, and (c) interactions and nonlinear effects of risk factors on mortality. The model was applied to 25-year follow-up data from cohorts of eastern (N = 823) and western (N = 888) Finnish men using pulse pressure, diastolic blood pressure, body mass index, total cholesterol, vital capacity index, cigarette smoking, and heart rate as risk factors. At age 40, men in the west had a life expectancy 2.4 years higher. Of the difference 29% (0.7 years) was associated with area differences in risk factor means, variances, and their change with age. The remainder, 1.7 years, was associated with age differences in the relation of risk factor interactions to CVD mortality. Possible reasons for these differences, such as joint elevation of several risk factors inducing rapid progression of atherogenesis, are discussed. No significant area differences were observed for mortality from either cancer or other causes.


Stimuli for acquired resistance to Heligmosomoides polygyrus from intestinal tissue resident L3 and L4 larvae. L3 and L4 stages of H.polygyrus were prevented from developing further and were probably killed within 24 h of treatment with ivermectin although total parasite burdens, particularly when treatment was given 4-6 days after infection, declined over a longer period lasting several days. Strong resistance to challenge infection was expressed by infected mice dosed with ivermectin during the tissue phase of larval development. Even immunizing infections as brief as 12-36 h (when only L3 larvae would have been present in the mucosa) elicited strong acquired immunity. When infections were terminated 4-6 days after infection, acquired resistance was 95-100%. The stronger resistance of mice exposed to both L3 and L4 stages was associated with the recognition of low molecular weight polypeptides in adult worm homogenate and there was a highly significant correlation between percentage protection and anti-L4/anti-adult worm serum IgG1 antibodies.


Hydrolysis of L-leucine methyl ester by Leishmania mexicana mexicana amastigote cysteine proteinases. The main cysteine proteinases of the amastigote form of Leishmania mexicana mexicana were partially purified by gel filtration and ion exchange chromatography. The latter procedure resulted in the separation of some individual cysteine proteinases, as demonstrated by gelatin-sodium dodecyl sulphatepolyacrylamide gel electrophoresis. Fractions containing the partially purified proteinases rapidly hydrolysed L-leucine methyl ester to leucine. The activity towards this compound co-eluted with and resembled the parasite's cysteine proteinase activity. The results suggest that amastigotes of L.m.mexicana are susceptible to L-leucine methyl ester because this compound is rapidly hydrolysed by cysteine proteinases that occur in abundance in the megasomes of this stage.


The influence of weather and egg contamination on the development of third-stage larvae of Cooperia oncophora on pasture. The influence of weather and egg contamination on the dynamics of herbage contamination with infective larave of Cooperia oncophora was investigated on artificially contaminated grass plots and in a grazing experiment with 24 first-year grazing calves from May to October 1987 in Lower Saxony, Germany. On the experimental plots the larval translation was highest at the beginning of July and in the second part of September, following high mean weekly temperatures. Between July and September peak recovery of larvae from herbage occurred 4 weeks after contamination. A seasonal pattern of larval translation similar to that on the experimental plots could be demonstrated on the grazed pastures when the number of larvae per m2 of pasture had been adjusted to the previous egg output by means of a contamination index. The resulting 'relative larval density' is regarded as a good indicator for larval development on pasture. From July to September the larval population on pasture resulted mainly from the egg contamination 2-3 weeks earlier. The short persistence of the infective larvae on herbage was probably due to the frequent and heavy rainfall throughout the season, causing a passive washout of larvae into the soil. On single pastures the larval density started to increase within 1 week after the calves had first contact with these fields. The impact of the calves on the distribution of larvae is discussed.


Analysis of the composition of samples of Babesia bovis and the influence of different environmental conditions on genetically distinct subpopulations. A recombinant DNA probe specific for a tandemly repeated sequence located within the BoVA1 gene of Babesia bovis was used to analyse 10 independent samples of B. bovis. Twelve different alleles of the BoVA1 gene and flanking regions were identified in the 18 different subpopulations analysed. Most samples of B. bovis originally derived from single animals contained more than one genetically distinct subpopulation. However, only one population of parasites was identified in samples of the Ka line used in Australia from 1979 until 1990 as the live attenuated vaccine strain. In contrast, the replacement attenuated vaccine line, Ta, contained two genetically distinct subpopulations of parasites. Changes in the ratios of subpopulations of parasites were identified during attenuation and under different culture conditions. Batch-to-batch variation in the composition of doses of the live attenuated vaccine may lead to differences in efficacy and in severity of the infection associated with vaccination.


The influence of Mesocestoides corti on subsequent Angiostrongylus cantonensis infections in mice. The influence of Mesocestoides corti on subsequent Angiostrongylus cantonensis infection in mice (C57BL/6 and BALB/c) was assessed. Both strains of mice infected with M. corti demonstrated a peak blood eosinophilia at around 3 weeks post-infection (p.i.). C57BL/6 and BALB/c mice primarily infected with M. corti were given A. cantonensis infection 18 days later, but pre-existing M. corti infection did not affect the recovery of intracranial worms of A. cantonensis at day 21 p.i. BALB/c mice with mixed parasite infections showed low morbidity and mortality as compared with mice singly infected with A. cantonensis and some mice demonstrated a pulmonary migration of intracranial worms. In C57BL/6 mice, intracranial worms were killed and thus all mice survived. C57BL/6 mice with mixed parasite infections failed to resist A. cantonensis reinfection. The blastogenic responses of spleen cells against A. cantonensis antigen were lower in BALB/c than in C57BL/6 mice and mixed parasite infections also resulted in less blastogenic responses against both concanavalin A and A. cantonensis antigen than monoinfection. The recovery of M. corti biomass was significantly higher in mice with mixed parasite infections than mice with monoinfection with M. corti. These data suggest a distinct difference in response to A. cantonensis infection between C57BL/6 and BALB/c mice, and the induction of immunosuppression in both mouse strains following M. corti infection. Blood eosinophilia provoked by M. corti infection is not directly associated with the killing of worms in subsequent A. cantonensis infection.


A preliminary study of the effect of microclimate on third-stage larvae of Haemonchus contortus and Haemonchus placei on irrigated pasture. Assessments were made on the influence of several microclimatic variables on the availability of third-stage larvae of Haemonchus contortus and Haemonchus placei on four strata of irrigated Kikuyu pasture. Three replicates of these pasture samples were collected on 18 sample days over 12 months and the log10 mean counts of the larvae recovered were analysed by a step-wise regression model. Predictors for the log counts of the four strata for the two nematode species included relative humidity, illumination, air temperature and windspeed. The effect of air temperature on larvae of both Haemonchus species was similar; as air temperature increased, the number of larvae on pasture increased. The inverse was true for windspeed; as windspeed increased larval counts decreased. For H. contortus, relative humidity increased as the number of larvae increased on all strata except upper herbage. The R2 values ranged from 0.11 to 0.21 for H. contortus and from 0.04 to 0.12 for H. placei. Under the conditions of this study, only 21% of the effect on H. contortus and 12% on H. placei third-stage larvae on pasture can be explained by microclimatic conditions.


Determinants of host-specificity in parasites of freshwater fishes. Factors responsible for interspecific variability in host-specificity were investigated within 15 genera (including 176 species) of metazoan parasites found in Canadian freshwater fish. For each species in a genus, the parasite's number of known hosts was determined from published host-parasite records. The effects of the total number and mean size of potential hosts (i.e. all fish species belonging to the family or families that include a parasite's known hosts) on number of hosts of congeneric species were evaluated using multiple regressions. Since parasite species that have been recorded often tend to have greater numbers of known hosts than do seldom-recorded parasites, it was necessary to control for the confounding effect of study intensity. In all parasite genera, whether from highly specific taxa such as monogeneans or from less host-specific ones, there was a positive relationship between the number of potential hosts and the number of known hosts. However, no consistent relationships were observed between the mean size of potential hosts and number of known hosts. These results suggest that the availability of suitable host species may have been a key factor limiting the colonization of new hosts by fish parasites.


Nymphal Ixodes dammini: models of the temporal abundance patterns. A difference equation model was developed to explore the sensitivity of the temporal pattern of relative abundance of active, host-seeking nymphal Ixodes dammini. Inputs to the model were the temporal patterns of recruitment of nymphs into the active class, mortality and successful acquisition of hosts by the ticks. Input parameters were varied both in the temporal pattern (shape) and in the cumulative level (summed over the period of activity). The output of the models, the temporal abundance pattern, was examined for (1) overall shape and (2) the timing of the peak abundance of host-seeking nymphs. The shape of the temporal pattern of nymphal abundance was not sensitive to changes in the shape of the functions used as input for host-finding. The time of peak abundance of nymphs is slightly sensitive to changes in the overall level of host-finding and mortality. When more ticks are removed from the active class (host-finding or mortality increasing), the time of the peak abundance of the nymphs shifts earlier. However, this shift is small compared to variation in field data. The general shape of the activity pattern was sensitive to changes in the temporal pattern of recruitment. A left-skewed distribution produced output which most resembles field data. The temporal pattern of nymphs entering the active class is important, and is an area which needs further empirical work.


Immunization against geographical isolates of Trichinella spiralis in mice. Partially purified antigen preparations from six isolates of Trichinella spiralis were used to immunize mice. Immunogenicity of the antigens was assessed in terms of antibody and lymphocyte responses and ability to stimulate protective immunity against challenge. Isolate antigens showed considerable cross-reactivity, and all elicited protective responses. Two major patterns of immunizing ability could be distinguished: (a) isolates that immunized well against heterologous challenge and elicited good immunity in London isolate-immunized mice (C-76 and Laso), and (b) isolates that immunized poorly against heterologous challenge and were least effective in London isolate-immunized mice (GM-1 and Mad-83). The immunogenicity of one isolate (C-76) was markedly greater than the others, inducing rapid loss in unvaccinated mice, almost complete protection in London isolate-immunized mice, and immunity in London isolate-challenged mice equivalent to the homologous antigen. These variations in immunogenicity, cross-reactivity and immunizing ability are discussed in terms of constraints that may operate against the development and use of vaccines against parasites that are widely distributed geographically.


A model for nematodiasis in New Zealand lambs. A strategic model is described for the epidemiology of mixed nematode infections in New Zealand lambs. The model successfully reproduces known patterns of parasite epidemiology and production loss in lambs under currently implemented control strategies. The variation in model output during sensitivity analysis was within acceptable limits defined by field data. Model output was most sensitive to variation in parameters affecting survival and migration of the free-living stages and host resistance to infection, suggesting that these factors are most influential in regulating parasite populations. It is intended to use the model to focus research on key aspects of nematode epidemiology and control and, following the incorporation of appropriate genetic mechanisms, anthelmintic resistance.


Predisposition to reinfection by intestinal helminths after chemotherapy in south Thailand. Rates of reinfection by the intestinal helminths hookworm, Ascaris lumbricoides and Trichuris trichiura after chemotherapy were studied in two villages in Phang-Nga Province, southern Thailand. It was found that intensity of infection levels attained after reinfection correlated positively with pretreatment intensities of infection for all parasites. This implies that certain persons in the community are predisposed to receiving high numbers of worms, due either to environmental or personal risk factors. Therefore, it would be advantageous to identify such persons and treat them preferentially. Targeted chemotherapy, however, should be combined with efforts to identify the risk factors that vary within the community and direct educational efforts or environmental intervention towards the section of the community most affected by the parasites.


Coccidia of the domestic goat (Capra hircus) in Saudi Arabia. Faeces of 228 domestic goats (Capra hircus) from the central region of Saudi Arabia were examined for the presence of coccidian oocysts. Ten species of coccidia were identified and described. A total of 90.3% of the specimens were positive, most of them contained 100-1000 oocysts per g of faecal sample. Kids less than 1 year old had higher oocyst counts than goatlings or adult goats. Mixed infections with three to five species were found in 69.7% of the specimens and six to eight species were found in 10.1%. Eimeria arloingi and E. hirci were most prevalent. E. alijevi, E. ninakohlyakimovae, E. caprina, E. christenseni and E. apsheronica were less common. E. jolchijevi, E. caprovina and E. punctata were relatively rare.


Intestinal contractions and migration behaviour in Hymenolepis diminuta. The aim of this study was to determine if intestinal contractions were important in the migration behaviour of the rat tapeworm Hymenolepis diminuta. The objectives were to investigate the intestinal motility responses of the host to a meal which initiates worm migration, and the worms' responses to an artificial peristaltic contraction. A 1 g glucose meal elicited a significant orad migration by H. diminuta in the small intestine of the rat host when compared to water-fed controls (P less than 0.05). The glucose meal also significantly increased the transit rate, and thus, frequency of intestinal contractions in the small intestine of the rat, when compared to water-fed controls (P less than 0.05). Application of a circumintestinal ligature (6.3 g) (simulating an intestinal peristaltic contraction) resulted in significant worm migration when the ligature was applied in regions containing the worm's strobila as compared to controls where loose ligatures were tied in regions containing the strobila, or to controls where tight ligatures were tied ahead of the worm's strobila. These results suggest that H. diminuta migrates in an orad direction in response to the mechanical pressure produced by intestinal contractions induced by host feeding. It is concluded that contractions of the small intestine are an important cue in the migration behaviour of this cestode.