Eradication of minimal disease in severe combined immunodeficient mice with disseminated Daudi lymphoma using chemotherapy and an immunotoxin cocktail

Severe combined immunodeficient (SCID) mice injected intravenously with a human Burkitt's lymphoma cell line (Daudi) develop disseminated lymphoma (SCID/Daudi), which is fatal in 100% of the mice. Early treatment of these mice with either an immunotoxin (IT) cocktail (consisting of anti-CD19-ricin A chain plus anti-CD22-ricin A chain) or chemotherapy significantly prolonged survival but was not curative. Combination therapy with the IT cocktail and any one of three chemotherapeutic drugs (doxorubicin, cytoxan, or camptothecin) cured the mice. Cure was demonstrated by both histopathologic examination of treated mice and, more importantly, by adoptive transfer of cells from organs of the cured mice to naive SCID mice where 100 tumor cells would have caused disease in the recipients. These results provide a strong rationale for combining IT therapy with conventional chemotherapy in the treatment of B-cell neoplasia.

Anti-CD19 inhibits the growth of human B-cell tumor lines in vitro and of Daudi cells in SCID mice by inducing cell cycle arrest

In this report, we extend our previous findings that IgG or F(ab')2 fragments of HD37 anti-CD19 antibody (Ab) in combination with the immunotoxin (IT), RFB4-anti-CD22-deglycosylated ricin A chain (dgA) (but neither reagent alone), prolonged the survival of SCID mice with disseminated human Daudi lymphoma (SCID/Daudi mice) to 1 year at which time they still remained tumor-free. We explored the mechanisms by which the HD37 Ab exerts antitumor activity in vivo by studying its activity in vitro. We found that it has antiproliferative activity (IC50 = 5.2 - 9.8 x 10(-7) mol/L) on three CD19+ Burkitt's lymphoma cell lines (Daudi, Raji, and Namalwa) but not on a weakly CD19-positive (CD19lo) pre-B cell tumor (Nalm-6). The inhibitory effect was manifested by cell cycle arrest, but not apoptosis. Results using three additional anti-CD19 Abs, suggest that the affinity of the antibody and possibly the epitope which it recognizes may effect its capacity to transmit a signal that induces cell cycle arrest. Hence, therapeutically useful Abs may exert anti-tumor activity by a variety of mechanisms, each of which should be evaluated before undertaking clinical trials in humans.

Food shortages and an epidemic of optic and peripheral neuropathy in Cuba

From late 1991 to mid-1993, cases of optic neuropathy of unknown etiology, which first appeared in unusual numbers in a western province of Cuba, spread and multiplied throughout the island. The dominant symptoms changed, becoming increasingly those of peripheral neuropathy. Incidence rates peaked in April 1993. An estimated 50,000 cases were reported. The majority were adult men and women (aged about 25-65), with comparatively few children or elderly people being affected. The cause has yet to be delineated. However, food shortages and radical changes in diet resulting from the longstanding US trade embargo and the recent loss of Eastern Europe as Cuba's trading partner have compromised nutritional status, especially B-vitamin sufficiency, and appear to be related to the neuropathic illnesses. In April 1993, the Cuban government began distributing vitamin supplements to every citizen. Causal hypotheses include tobacco-alcohol or "nutritional" amblyopia; cyanide toxicity from cassava; toxic legumes introduced as supplements to scarce flour; other toxins, for example pesticides, or a "blue mold" on tobacco; enterovirus; and a hereditary enzyme deficiency in affected persons. None of these factors appears to be present in all cases, but it is generally believed that an interaction of some toxin or toxins, in combination with nutritional deficiency, is likely to be the major cause.

Transesophageal echocardiography during cardiopulmonary resuscitation

Transesophageal echocardiography is ideally suited for imaging during CPR because high-quality images can be obtained immediately and continuously without interruption of cardiac compression and ventilation. Use of TEE during CPR is increasing to help monitor resuscitative efforts, for diagnosis, to assist in understanding the physiology of blood flow, and for evaluation of new methods of CPR.

Intragastric glucose but not fructose conditions robust flavor preferences in rats

Prior work indicates that glucose and fructose differ in their postingestive reinforcing effects. The present study investigated this phenomenon by training rats to associate the intake of flavored water with intragastric (IG) infusions of 16% sugar solutions. In experiment 1, rats had one flavor [conditional stimulus (CS)] paired with IG sugar infusions (CS+; e.g., cherry) and another flavor paired with IG water (CS-; e.g., grape) 23 h/day; Chow was available ad libitum. In subsequent choice tests, rats infused with glucose displayed a strong preference (89%) for the CS+ flavor, whereas rats infused with fructose showed only a small and nonreliable CS+ flavor preference (62%). When next trained to associate one flavor (e.g., orange) with IG glucose and another flavor (e.g., strawberry) with IG fructose, rats in both groups developed a significant preference (81%) for the glucose-paired flavor. In experiment 2, food-deprived rats were trained 2 h/day to associate a CS+ flavor with IG sugar and a CS- flavor with IG water infusions. The glucose-reinforced rats displayed a near-total preference (95%) for the CS+ flavor, whereas fructose-reinforced rats showed a much smaller CS+ preference (67%). The preference findings indicate that the postingestive consequences of glucose are much more reinforcing than those of fructose. It appears that food conditioning is mediated by chemospecific actions of nutrients rather than their general satiating or energy repleting effects.

The antitumor activity of an anti-CD22 immunotoxin in SCID mice with disseminated Daudi lymphoma is enhanced by either an anti-CD19 antibody or an anti-CD19 immunotoxin

The antitumor activities of immunotoxins (ITs) constructed with deglycosylated ricin A chain (dgA) and either anti-CD19 (HD37) or anti-CD22 (RFB4) monoclonal antibodies were compared in SCID mice with disseminated human Daudi lymphoma (SCID/Daudi). As reported previously, after intravenous injection with Daudi cells, SCID mice develop disseminated lymphoma, which infiltrates the vertebral column and causes paralysis of the hind legs before death. The mean paralysis time (MPT) has been taken as an end point in this tumor model. We have previously reported that early treatment of SCID/Daudi mice with RFB4 coupled to dgA prolongs the MPT in a manner consistent with the killing of 4 logs of tumor cells. In the present study, we show that HD37-dgA kills 2 logs of tumor cells. The lower potency of the HD37-dgA is consistent with its lower IC50 on Daudi cells in vitro. We further show that the antitumor activity of a mixture of HD37-dgA and RFB4-dgA is significantly enhanced in SCID/Daudi mice and is consistent with the killing in excess of 5 logs of tumor cells. However, identical enhancement was observed when a mixture of the RFB4-dgA and the HD37 antibody was administered. In contrast, enhancement was not observed when mice were injected with a mixture of the RFB4 antibody and the HD37-dgA. The results indicate that a "cocktail" of HD37 antibody and RFB4-dgA immunotoxin can have significant antitumor activity in this mouse model of lymphoma and suggest that combinations of particular antibodies and ITs may have cooperative antitumor activity.

Intestinal helminthiases in relation to the socioeconomic environment of Panamanian children

A cross-sectional investigation was made into ascariasis and nutritional status in Panamanian preschool children from October 1983 to July 1984. Within this framework, an analysis was undertaken of possible relationships between a range of intestinal helminthiases and the socioeconomic status of the participants. Attention was paid to caregiver's education, parental occupation, family earnings, quality of housing and sanitation in the assessment of socioeconomic status. On this basis, strong associations were established between the socioeconomic status of the children and infection with Ascaris lumbricoides, Trichuris trichiura and hookworm. In general, the prevalence of single and multiple helminth infections was significantly higher in children living in housing made of wood or bamboo than in those living in housing made of concrete blocks. The same pattern applied to levels of sanitation. Ascaris lumbricoides occurred more frequently in children of mothers with the least formal education and in children living in relatively crowded conditions. Evidence was also obtained to indicate that the intensity of the intestinal helminth infections was greater in the children from the poorer environment. Since children from poorer socioeconomic conditions might be more exposed to infective stages than those from a better environment, the possible role of socioeconomic factors in contributing to the predisposition of some individuals to harbour large worm burdens of intestinal helminths was briefly discussed.

Maternal employment and child nutrition in Panama

The major question addressed in this research is: 'Does maternal employment affect child dietary intake and nutritional status and if so, what mediating factors are important?' Maternal employment has been seen to have two conflicting effects on child nutrition--via increased income and decreased time available in the household. Efficiency and preferences of the household will vary and are likely to be of major importance in these relationships. A comprehensive measure of these inputs was devised using the concept of 'differentiation', defined as the capacity to process a diversity of information types. Various indicators of this concept were identified at both the household and the maternal levels and entered into a principal component analysis which generated composite variables. The data, including weighed dietary intakes and observed time use for mothers and substitutes, were collected during a 1 year stay in Panama. The results of a series of stepwise and multiple regression analyses lead to the conclusion that maternal employment, in this population, has a positive effect on child nutrition. In most cases, employment status enters into interactions with a variety of effect modifiers, suggesting the highly situational aspect of the relationships. Maternal time in home production decreases with her employment but total household time in these activities does not, due to the inputs of other household members. Maternal income seems to be of key importance to dietary intake. The maternal differentiation variable is consistently and positively related to dietary and anthropometric outcomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Contributions of ascariasis to poor nutritional status in children from Chiriqui Province, Republic of Panama

Relationships between ascariasis and lactose digestion and between ascariasis and food transit time from mouth to caecum were investigated in young children from Chiriqui Province, Republic of Panama. The breath hydrogen method was used in both studies. Ascaris-infected children showed a significantly poorer degree of lactose digestion following a test oral load than uninfected children. Recovery of the capacity of the children to digest lactose was still not fully complete for at least 3 weeks following anthelmintic treatment. On average, the mouth-to-caecum transit time was similar in infected and uninfected children, but among the Ascaris-infected children the transit time tended to be shorter in relation to the intensity of infection. Evidence from a cross-sectional survey indicated that ascariasis was significantly associated with reduced plasma vitamin A and carotenoid concentrations. This relationship remained after controlling for a range of socio-economic variables. Ascaris-infected children were frequently found to have lower haematocrits and blood haemoglobin concentrations than uninfected children, but these relationships could not be attributed to ascariasis alone.

Ascaris lumbricoides infection in pre-school children from Chiriqui Province, Panama

An epidemiological survey of intestinal parasitic infections was conducted in a sample of 203 children aged 3-5 years from a semi-urban and a rural community in Chiriqui, Panama, in 1983-4. On the basis of stool examinations, the prevalences of Ascaris lumbricoides, Trichuris trichiura, hookworm, Giardia intestinalis, Entamoeba spp. and Strongyloides stercoralis were found to be 27, 34, 14, 15, 5 and 4% respectively. The results from children from the two communities were compared. Polyparasitism occurred significantly more often in rural than semi-urban children. Following anthelmintic treatment with levamisole, the numbers of A. lumbricoides passed/child were recorded and the frequency distribution of the parasite was observed to be highly aggregated with a variance to mean ratio of 10.2. For A. lumbricoides, relationships between worm burden, worm biomass and egg production were investigated. In the data analysis, an attempt was made to explore the influence of numbers of male worms on egg production. The results are compared with those obtained during other recent studies on the epidemiology of A. lumbricoides infection in other countries.

Successful rat pancreatic islet allotransplantation without recipient immunosuppression

Pancreatic islets from Wistar Furth (RT1u) rats are rejected by 5 days after transplantation into the liver of the diabetic Lewis (RT11) rat. Pretreatment of Wistar Furth islets by culture for 7-10 days in 95% O2 5% CO2 reduces immunogenicity permitting successful allotransplantation as defined by normal blood and 24-hr urinary glucose values.

Some aspects of post-traumatic elbow stiffness

In this article the anatomy of the soft tissues around the elbow joint is described in relation to the causation of post-traumatic elbow stiffness. Examples of the ways in which significant damage to these tissues may occur after injury are discussed. It is suggested how arthrography may help in the diagnosis of the condition.

The Tower of London bomb explosion

After the detonation of a bomb in the Tower of London 37 people were brought to St. Bartholomew's Hospital. The explosion caused numerous severe injuries of a type rarely seen in peacetime.